4 Clinical Pictures



10.1055/b-0039-173876

4 Clinical Pictures



4.1 Shunt Defects



4.1.1 Atrial Septal Defect

Philipp Beerbaum, Joachim Lotz, Michael Steinmetz

Definition

The term “atrial septal defect” refers to various morphological and embryological defects of the atrial septum that in isolation, comprise a total of 5–10% of all congenital heart defects. 1 ASD often occurs in conjunction with other cardiovascular defects. Atrial septal defects should be distinguished from open PFO. Fetal atrial communication persists in approximately one-third of all children. Its clinical significance results primarily from the likelihood of paradoxical embolism of thrombi occurring from the venous area into the left systemic arterial area, and then into the aortic branches. Thrombi of this type can lead to strokes or peripheral embolisms.



Classification

The following three, most common types, will be described in detail (▶Fig. 4.1):

Fig. 4.1 Various forms of ASD. Schematic depiction. ASD I = primum atrial septal defect (incl. atrioventricular septal defect) ASD II = secundum atrial septal defect (aka fossa ovalis defect) CS = coronary sinus (entrance) CT = crista terminalis IVC = inferior vena cava RAU = right auricle SVC = superior vena cava SVD1 = type 1 sinus venosus defect (superior sinus venosus defect) SVD2 = type 2 sinus venosus defect (inferior sinus venosus defect) V = ventricle



  • Secundum ASD: ASD II also known as fossa ovalis defect (approximately 70% of all ASDs), occurs in the central portion of the atrial septum with no connection to the atrioventricular valves (▶Fig. 4.1, ▶Fig. 4.2)



  • Primum ASD: ASD I also known as partial AVSD, comprises approximately 15–20% of all ASDs. This type of defect is situated caudally and is connected to the atrioventricular valves (▶Fig. 4.1, ▶Fig. 4.3)



  • Sinus venosus ASD: SVD comprising approximately 10–15% of all ASDs




    • superior: most common form (▶Fig. 4.1); near the connection to the superior vena cava



    • inferior: less common; also known as “coronary sinus ASD” (▶Fig. 4.1); 2 near the connection to the inferior vena cava

Fig. 4.2 Large ASD II. Two patients (a, b: patient 1; c–e: patient 2). Each asterisk indicates an ASD. AAo = ascending aorta LA = left atrium LV = left ventricle RA = right atrium RV = right ventricle SVC = superior vena cava a 2-D echo, 4-chamber view, without color Doppler. b 2-D echo of the same patient, 4-chamber view, with color Doppler. The left–right shunt is clearly visible. c 2-D echo of a different patient with ASD II (see d and e), 4-chamber view. d SSFP cine MRI, 4-chamber view, of the patient from c with clearly visible ASD II. Minor pericardial effusion is also visible near the atrioventricular valve in the left ventricle. e Tangential SSFP cine MRI, parallel to the septum, for the patient from c and d. The size of the defect (approximately 10 mm) can be measured based on this slice.
Fig. 4.3 Large, valve-adjacent ASD I. 3-D TEE; view from left atrium. The asterisk indicates the site of the ASD.

Coronary sinus defect (also known as unroofed coronary sinus) is an uncommon defect type (3–5% of all ASDs).



Note

SVD often occurs in conjunction with PAPVR (see Partial Pulmonary Venous Anomalies) (▶Fig. 4.4 and ▶Fig. 4.5). Thus, once SVD has been established, it is crucial to always search for concurrent PAPVR.

Fig. 4.4 SVD with concurrent PAPVR of a right superior pulmonary vein to the superior vena cava and right atrium. The single asterisk marks the right superior pulmonary vein. The PAPVR is especially easy to visualize using a 3-D whole heart MRI sequence (a). Both in MRI and MDCT (▶Fig. 4.5), a 3-D data set offers the opportunity to depict the surface via volume rendering (b), as well as to create precise reconstructions using multiplanar reformats in various orientations (c, d). LV = left ventricle RA = right atrium RV = right ventricle a 3-D whole-heart MRI sequence with transverse reconstruction at four different levels to visualize the PAPVR (asterisk) and SVD (double asterisk). b MRI, volume rendering. c MRI, coronal multiplanar reformat. d MRI, transverse multiplanar reformat.
Fig. 4.5 Superior SVD accompanied by PAPVR. Sixty-five-year-old man. The thoracic X-ray (a) in p.-a. projection clearly depicts the enlargement of the right atrium and the significantly enlarged pulmonary arteries and veins (primarily on the right side, in this instance). The thoracic X-ray in lateral projection (b), in particular, shows the clear enlargement of the right ventricle and RVOT, as well as the pulmonary artery (“narrowing” of the retrosternal space) and pulmonary veins (▶Table 4.1). Enlargement of the right ventricle with volume overload can also be identified easily using CT short-axis reconstruction (c) of the pulmonary artery. The volume overload of the right ventricle is clearly depicted by the flat curvature of the interventricular septum. The 3-D MDCT data set depicts the ASD (double asterisk), and the anomalous pulmonary venous connection to the superior vena cava (asterisk), using various angled multiplanar reconstructions (d–g). RV = right ventricle Ao = aorta LA = left atrium LV = left ventricle PA = pulmonary artery RA = right atrium RAU = right auricle RPA = right pulmonary artery RV = right ventricle SVC = superior vena cava a P.-a. thoracic X-ray. b Lateral thoracic X-ray. c Short-axis reconstruction (75% of the RR interval) of the retrospectively gated MDCT data set (64 rows). d Multiplanar reconstruction of the 3-D MDCT data set (coronal cross-sectional orientation) through the anomalously connected pulmonary veins (asterisk). The colored lines represent the sectional planes for reconstructing e, f, and g. e Multiplanar reconstruction of the 3-D MDCT data set in transverse cross-sectional orientation (planning cross-section, see yellow line in d). The orange line corresponds to the planning cross-section for the coronal reconstruction (f) to depict the superior SVD. f Multiplanar reconstruction of the 3-D MDCT data set for the coronal reconstruction of the superior SVD (double asterisk). This sectional plane corresponds to the orange line in d and e. g Angled transverse multiplanar reconstruction, running through the SVD, of the 3-D MDCT data set. The sectional planes used for reconstruction are marked as blue lines in d and f.


Hemodynamics

An ASD allows passage of blood between the left and right atrium, also known as a “shunt.” The direction and shunt volume result from the varying compliance (elasticity) of the left and right ventricles. The right ventricle is less muscular and thus more elastic during diastole (meaning it demonstrates higher compliance) than the left ventricle. The reason for this is the low right ventricular afterload, since pulmonary arteriolar resistance comprises only approximately 10–15% of systemic arteriolar resistance, which is significant to the afterload of the left ventricle.


The left–right shunt that generally results from this phenomenon occurs primarily during late ventricular diastole and early ventricular systole. Depending on the size of the shunt, this increases or decreases volume load in the right atrium and right ventricle (▶Fig. 4.6), in addition to the pulmonary vessels (arteries and veins), which dilate accordingly (▶Fig. 4.7).

Fig. 4.6 Right ventricular volume overload caused by an ASD. Right ventricular volume overload caused by an ASD is already visible adjacent to the transducer using a 2-D TTE along the parasternal long axis, even in a B-mode image (a). Precise quantification is possible during M-mode, based on the end diastolic and end systolic diameters of the right ventricle. The left ventricular parameters can also be communicated in this fashion. Due to the complex right ventricular geometry, MRI (b) using the slice summation method (Simpson’s method) still offers significant advantages compared to echocardiography. The end diastolic short-axis slices via the complete right and left ventricle using cine MRI and SSFP sequences for the same patient depict the significantly dilated right ventricle due to pronounced volume overload through the resulting left–right shunt. LV = left ventricle RV = right ventricle. a 2-D-TTE, parasternal long axis (B image, M-mode). b 2-D SSFP cine MRI.
Fig. 4.7 ASD accompanied by dilation of the pulmonary vessels. Thoracic X-rays (a, b) of an adult male patient with significant dilation of the main pulmonary artery (MPA) and branches, right atrium, right ventricle, and RVOT, as well as a volume overload in the lungs. The MIP reconstruction of a contrast-enhanced MRA (c) and right ventricular long axis of an SSFP cine MRI sequence during systole (d) depicts the dilated right ventricle of the same patient, and the significantly dilated right and left pulmonary arteries. MPA = main pulmonary artery (truncus pulmonalis) RA = right atrium RV = right ventricle RVOT = right ventricular outflow tract a P.-a. thoracic X-ray. b Lateral thoracic X-ray. c MIP reconstruction of a contrast-enhanced MRA, ventral view. d SSFP cine MRI sequence during systole, right ventricular long axis, with approximate lateral projection corresponding to b.

On the other hand, the left atrium retains this additional shunt volume after it passes through the lungs again. The left atrium is able to “decompress” due to the defect and is thus, in effect, not subject to volume overload (▶Table 4.1). Throughout the course of the patient’s life, the relative difference between ventricular compliance continues to increase, meaning that the left ventricle becomes increasingly inelastic as the patient ages. If an ASD is already present, this decreasing elasticity further exacerbates the left–right shunt. 3 Correspondingly, thoracic X-ray in p.-a. view depict both increased pulmonary vascular markings and a dilated pulmonary segment. The right atrium’s dilation is also expressed in the form of pronounced right atrial contour (▶Fig. 4.7a). In contrast, this dilation of the right ventricle and the RVOT are visible when taking images from lateral positions, primarily in the retrosternal area (▶Fig. 4.7 b and d).



































Table 4.1 Volume load of the various cardiovascular compartments in a case of ASD.

Cardiovascular compartment


Volume load


Right atrium


++


Right ventricle


++


Pulmonary arteries


++


Pulmonary veins


++


Left atrium



Left ventricle



Aorta and conduit arteries



Systemic veins




Clinical Issues

With the exception of bicuspid aortic valve and mitral valve prolapse syndrome, ASD is the most common heart defect diagnosed in adults (▶Fig. 4.5 and ▶Fig. 4.7). In part, this is due to the fact that the right ventricle initially handles the excess volume load well and under these conditions can also increase cardiac output.



Natural Progression and Indication for Treatment

Without treatment, clinical symptoms such as right ventricular heart failure, cardiac rhythm disorders, or progressive pulmonary arterial hypertonia 4 will begin to manifest. The indication for ASD closure is a result of studies on the natural progression of defects diagnosed later in life. 4 , 5 This data reveals that heart failure with exertional dyspnea and predominantly atrial, often difficult-to-treat tachycardic rhythm disorders occur with increasing frequency after age 30. After closure of a defect, these disorders are often irreversible. The indication for treatment is more frequently determined based on the extent of right ventricular volume load than on shunt ratio (Q p:Q s ratio) alone. 6



Treatment Options and Preinterventional Diagnostics

Catheter-based interventional closure has become possible for the majority of type II ASDs, and is widely regarded as the treatment of choice (▶Fig. 3.16 and ▶Fig. 3.17). All other types are treated surgically, which yield exceptional results. Categorizing the efficacy of various imaging procedures is based primarily on their ability to classify the ASD type precisely, and to determine the defect’s size and the dimensions of its margins compared to the surrounding cardiovascular structures. Additional diagnostic tasks include quantifying shunt volume, determining the volume’s effects on right and left ventricular function, and the morphological depiction of concurrent defects, such as anomalous pulmonary venous connections (▶Table 4.2). Precise, noninvasive quantification of shunt volume by determining the Q p:Q s ratio—meaning the cardiac output measured in the pulmonary artery (index “P”) and aorta (index “S” = systemic artery)—is one application of MRI flow measurement (▶Fig. 4.8). 7 , 8

Fig. 4.8 Determining shunt volume using MRI. Ao = aorta PA = pulmonary artery a Through-plane MRI flow measurement (perpendicular to the course of the vessel) in the aorta, anatomical modulus image. b Phase image of the aorta, indicating flow velocity and direction. Cranial flow is coded in a pale color in the phase image. The red circle indicates the point of flow measurement in the aorta for the red flow curve in e. c Through-plane MRI flow measurement (perpendicular to the course of the vessel) in the pulmonary artery; anatomical modulus image. d Phase image of the pulmonary artery, indicating flow velocity and direction. Cranial flow is coded in a pale color in the phase image. The blue circle indicates the location of flow measurement in the pulmonary artery for the blue flow curve in e. e Corresponding flow volume curves in the aorta (red) and pulmonary artery (blue) for a male patient with pronounced left–right shunt (Qp/Qs ratio greater than 2).



































Table 4.2 Preinterventional imaging diagnostics for an ASD.

Imaging methods


Focus


Value


2-D, 3-D TTE




  • Defect size and margins



  • Left–right shunt, qualitative



  • Right heart dilatation



  • Ruling out pulmonary and systemic venous anomalies


+++


2-D, 3-D TEE


see TTE


+++


Cardiac MRI




  • Quantifying the left–right shunt



  • Quantifying ventricular dilation and function



  • Measuring the defect (phase contrast method)



  • Anatomy of pulmonary and systemic veins


+++


(Backup method)


MDCT


Backup method in cases of unclear echocardiographical findings and contraindication against cardiac MRI; may be helpful in cases of pulmonary parenchymatic comorbidity or to prove the existence of concurrent vascular defects, such as anomalous pulmonary venous connections.


++


(Backup method)


Invasive (diagnostic) cardiac catheter examination




  • Measuring pressure and resistance (if indicated), pharmacological testing



  • In rare cases: invasive measurement of diastolic left ventricular functional parameters (e.g., left ventricular end diastolic diameter) in the event of suspected elevated risk of pulmonary edema after closure of an ASD



  • Ruling out pulmonary and systemic venous anomalies


+++


(in cases of pulmonary hypertonia and suspected left ventricular restriction)


ASD, atrial septal defect; MDCT, multidetector computed tomography; MRI, magnetic resonance imaging; TEE, transesophageal echocardiography; TTE, transthoracic echocardiography



Postoperative and Postinterventional Issues

Rhythm disorders and, in extremely rare cases, cyanosis concurrent with inferior ASD (occasionally with the option to shunt the lower caval vein into the left atrium) are among the issues that may occur after surgical or interventional ASD corrections. 9



Goals and Relative Value of Diagnostic Imaging

TTE is generally sufficient for preoperative diagnostics in children. 7 For adults, a thoracic X-ray may also be ordered due to morphological signs suggesting an ASD that are typically visible via imaging (▶Fig. 4.7). TEE plays a central role for older children and adults. Clinical practice has shown that especially for these older patients with ASDs cardiac MRI is selected more and more frequently as the first-choice method. 10 , 11 For younger children, however, tomographic procedures are used only rarely, and generally only as a backup method for echocardiography or for postinterventional follow-up exams (▶Table 4.2 and ▶Table 4.3). MRI has a special role, and CT has a backup role for visualizing a PAPVR within the scope of an SVD (▶Fig. 4.4). In particular, preparing multiplanar reformats of a 3-D MRA or of an MDCT data set (▶Fig. 4.5) facilitates preoperative planning. One particular strength of MRI is its ability to measure shunt volume noninvasively (▶Fig. 4.8) via flow measurement (using the phase contrast technique) in the aorta and pulmonary artery to calculate Q p:Q s ratios.





























Table 4.3 Postinterventional imaging diagnostics in cases of ASD.

Imaging methods


Value


TTE


+


TEE


+++


Cardiac MRI


++


MDCT


+


Invasive cardiac catheter diagnostics


+


ASD, atrial septal defect; MDCT, multidetector computed tomography; MRI, magnetic resonance imaging; TEE, transesophageal echocardiography; TTE, transthoracic echocardiography.



4.1.2 Ventricular Septal Defect

Philipp Beerbaum, Joachim Lotz, Michael Steinmetz

Definition

The term “ventricular septal defect” encompasses various morphological and embryological defects of the interventricular septum. Comprising a total of 15–20% of all congenital heart defects, VSDs are the most common. This does not include VSD that is very commonly concurrent with complex heart defects (especially cyanotic ones). Thus, VSD occurs in isolation in 90% of cases. 12 Classification is based on morphological criteria and takes into account the division of the ventricular septum into a pars membranacea and a pars muscularis. Also note that the tricuspid valve and its septal leaflet attach to the septum somewhat closer to the cardiac apex (provided no atrioventricular canal resulting from an endocardial cushion defect is present), which results in the ability to create a connection between the left ventricle and right atrium near this “atrioventricular septum.”



Classification

In principle, all membranous and muscular parts of the ventricular septum could be affected by a VSD. From a morphological or topographical perspective, the ventricular septum possesses an inlet segment near the cardiac base, a right ventricular trabeculated section that includes the apex cordis, and an outlet segment near the outflow tract toward the outlets of the great arteries (▶Fig. 4.9).

Fig. 4.9 Various types of VSDs. Schematic depiction. View from the right ventricle. In addition to subclassification as muscular or primarily membranous VSDs, it is also useful, from a clinical perspective, to describe VSDs based on their location in the inlet, trabecular, or outlet septum. AAo = ascending aorta ILS = inlet septum OLS = outlet septum PA = pulmonary artery RA = right atrium TS = trabeculated septum (trabeculated area) VSD-A = type A ventricular septal defect (perimembranous or subaortic ventricular septal defect) VSD-B = type B ventricular septal defect (subpulmonary or infundibular VSD) VSD-C = type C ventricular septal defect (muscular ventricular septal defect).

The trabeculated segment of the muscular ventricular septum can be further subdivided into the central, marginal, and apical portions (▶Fig. 4.14). This is significant to the extent that ventricular septal defects are generally described based on their anatomical position and their topographic and anatomical spatial relations (e.g., their position with respect to the atrioventricular valves or great arteries), since this type of classification results in various strategies for interventional treatment.


Classification of a VSD (▶Fig. 4.9):




  • Type A: Perimembranous (or subaortic) VSDs occurs (▶Fig. 4.10 and ▶Fig. 4.11) immediately inferior to the aortic valve in 70% of cases. Larger perimembranous or paramembranous VSDs are not limited to just the membranous portion, but also extend to the inlet septum, trabeculated septum (▶Fig. 4.12), or outlet septum.



  • Type B: A subpulmonary VSDs (▶Fig. 4.13) are located in the supracristal portion of the membranous ventricular septum and thus in the outlet septum. This defect is not infrequently complicated by the right coronary aortic cusp prolapsing into the VSD (▶Fig. 4.13), which can lead to progressive aortic valve insufficiency.



  • Type C: A muscular VSDs (approx. 10% of all VSDs) are fully surrounded by muscle and can occur anywhere in the muscular portion of the interventricular septum (▶Fig. 4.14). Hybrid forms can also occur.

Fig. 4.10 Malalignment VSD as a special form of a subaortic or perimembranous VSD (type A). Ao = aorta LA = left atrium LV = left ventricle RA = right atrium RV = right ventricle a 2-D TTE depiction, parasternal long axis. Isolated malalignment VSD in the anterior outlet septum (a–c, asterisk) resulting from a conotruncal defect. b Four-chamber view, without color Doppler. c Four-chamber view, with color Doppler. d Coronal slices through the defect (d, e, asterisk) and LVOT using an SSFP cine MRI sequence during systole. e 3-D echo depiction.
Fig. 4.11 Small, restrictive perimembranous or subaortic VSD (type A). The asterisk indicates the VSD (a, e–g). Ao = Aorta LA = left atrium LV = left ventricle; PA = pulmonary artery; RA = right atrium RV = right ventricle VSD = ventricular septal defect TV = tricuspid valve a 2-D TTE with Doppler (right) and without Doppler (left). b 2-D TTE, 4-chamber view. c Spectral Doppler with flow acceleration to a maximum of 5 m/s near the restrictive perimembranous VSD. d Enlarged left ventricular diameter and normal right ventricular diameters in echo M-mode. The right ventricle is thus not subject to the volume overload that typically occurs in cases of restrictive VSD (▶Table 4.5). e SSFP cine MRI, coronal slice orientation. f 3-D TEE: reconstructions of the small, restrictive VSD with a TEE viewing angle of 115°. g 3-D TEE: reconstructions of the small, restrictive VSD with a TEE viewing angle of 35°.
Fig. 4.12 Perimembranous VSD (type A) encompassing the membranous and trabecular portions of the septum. LA = left atrium LV = left ventricle RA = right atrium RV = right ventricle a Transverse T1w, turbo SE image triggered during diastole with the planning slice (dotted line) for b and c. b SSFP cine MRI during systole, section parallel to the VSD. c SSFP cine MRI during diastole, section parallel to the VSD.
Fig. 4.13 Subpulmonary or infundibular VSD (type B) with prolapsed right coronary cusp. The SSFP cine MRI sequence and LVOT slice clearly show the right coronary cusp prolapsed into the RVOT (a, b, asterisks). The short-axis slice depicts the subpulmonary VSD (c, asterisk). Ao = Aorta LA = left atrium LV = left ventricle PA = pulmonary artery RA = right atrium RV = right ventricle a SSFP cine MRI sequence, transverse section parallel to the valve. b LVOT slice. c Short-axis slice.
Fig. 4.14 Apical muscular VSD (type C). LA = left atrium RA = right atrium RV = right ventricle TV = tricuspid valve a 3-D echo with view from the right ventricle. b SSFP cine MRI, 4-chamber view (asterisk = VSD).


Note



  • An inlet VSD (▶Fig. 4.12) affects the same section of the septum as the VSD portion in cases of complete AVSD.



  • Membranous VSDs (types A and B) constitute 90% of all VSDs.


Special forms:




  • Atrioventricular canal VSD (approximately 6% of all VSDs) is handled separately in Chapter 4.1.3, Atrioventricular Septal Defect.



  • Malalignment VSD is categorized as a conotruncal defect (▶Fig. 4.10).



  • Gerbode VSD is a defect of the atrioventricular portion of the membranous septum. This results in a shunt between the left ventricle and right atrium. This may be due to the fact that the tricuspid valve and its septal leaflet attach a few millimeters further apically toward the membranous portion of the septum than the mitral valve on the other side of the ventricular septum. This disparity causes a hemodynamic change compared to other types of VSDs (see below and ▶Table 4.4).






































Table 4.4 Volume load of the various cardiovascular compartments in a case of VSD.

Cardiovascular compartment


Volume load


Right atrium



(+) in exceptional cases: VSD of the atrioventricular septum (Gerbode defect with a shunt from the left ventricle to the right atrium)


Right ventricle



(+) in exceptional cases: Gerbode defect (see above)


Pulmonary arteries


++


Pulmonary veins


++


Left atrium


++


Left ventricle


++


Aorta and conduit arteries



Systemic veins



VSD, ventricular septal defect.



Hemodynamics

For patients with isolated VSDs, clinical symptoms depend both on the defect’s size and the ratio of downstream pulmonary and systemic vessel resistance. The anatomical position of the VSD is, in contrast, less crucial. 12 , 13


In normal situations with low pulmonary arteriolar resistance, a left–right shunt occurs primarily during systole. During the contraction phase, the pulmonary artery supplies it directly, thus causing no volume overload in the right ventricle (▶Fig. 4.11 and ▶Fig. 4.13). Rather, this load is borne by the pulmonary vessels and left side of the heart. These cardiovascular structures can also dilate accordingly as a result of the volume overload (▶Table 4.4).


A very small defect is restrictive, and the shunt is, consequently, rather minor. A larger VSD can still release pressure, but the shunt remains largely relevant, provided that pulmonary arteriolar resistance is normal. A large VSD can cause pressure between the ventricles to equalize. In cases of normal pulmonary arteriolar resistance, this leads to heart failure due to massive left–right shunt with critical reduction of systemic cardiac output. If anatomical stenoses of the RVOT, pulmonary valve, or pulmonary vessel bed are also present, the left–right shunt will malfunction less critically, and heart failure generally will not occur.


Long-term exposure of the pulmonary vessel bed to pressure and volume overload can develop into a progressive and ultimately irreversible increase in pulmonary arteriolar resistance. In the most extreme cases, this is known as “Eisenmenger syndrome.” This can even cause shunt reversal with the development of cyanosis. This risk increases significantly after the first year of life. Thus, for cases of pressure-equalized VSDs, the defect should be closed beforehand.



Note

Cases of Gerbode defect result in a special hemodynamic situation, since this syndrome causes volume overload in the right atrium and ventricle. In contrast, restrictive defects of the other portions of the septum (as already mentioned) do not cause volume overload of the right atrium and ventricle, even if a large shunt volume is present.



Clinical Issues

Small VSDs are often first diagnosed in adulthood. Due to dyspnea and limited exercise capacity, larger defects are often noted during infancy as signs of cardiac failure, often within the scope of bronchopulmonary infections. 12 Cyanosis does not occur until after shunt reversal (Eisenmenger syndrome).



Natural Progression and Indication for Treatment

Most patients with isolated, small- to medium-sized VSDs have a good prognosis, especially since spontaneous decreases in size up to full regression can occur in up to 50% of patients, 13 primarily in cases of muscular VSD. The indication for treatment is determined primarily by a shunt ratio (Q p:Q s ratio) of 1.5:1 to 2:1, and/or if pulmonary arterial pressure increases to half that of systemic values. 12 Symptomatic children with large VSDs receive surgical treatment within the first 6 months of life, while asymptomatic children with pressure-separating VSDs but relevant left–right shunt volume, are treated already as toddlers. Additional indications for surgery include pressure-separating defects without relevant shunts if the right coronary aortic cusp prolapses into the VSD, particularly in cases of subpulmonary VSD position (▶Fig. 4.13), causing asymmetry of the aortic valve and aortic valve insufficiency.



Treatment Options and Preinterventional Diagnostics

Catheter interventional closure is primarily possible for muscular VSD, though it is fundamentally possible for cases of membranous VSD, as well. Especially in cases of Swiss cheese ventricular septum with multiple muscular VSDs, graduated treatment is often necessary. This entails a palliative surgical treatment by means of pulmonary artery banding, followed by a combined interventional surgical procedure, to be completed in tandem. For cases of large, isolated VSDs, surgical closure is the first-choice procedure and is generally performed from the right atrium from a trans-tricuspid view using a Dacron patch. Nowadays, trans-infundibular access is generally avoided.


Classifying the efficacy of the various imaging procedures prior to an intervention is based on the procedures’ ability to precisely determine size, visualize the localization, and quantify shunt volume and its effects on left and right ventricular function. Fundamentally, the VSD can already be visualized well using echocardiography (▶Fig. 4.10, ▶Fig. 4.11, ▶Fig. 4.13 and ▶Fig. 4.14). 3-D echocardiography, in particular, is especially helpful for peri-interventional and perioperative planning. Not infrequently, TEE is the final, decisive diagnostic method for particular constellations, such as Gerbode defect or aortic valve prolapse in cases of subpulmonary VSD (▶Fig. 4.13). Precise, noninvasive quantification of shunt volume by determining the Q p:Q s ratio remains within the domain of MRI flow measurement (▶Fig. 4.8) 7 , 8 in cases of both ASD and VSD, provided no other valve defects are present. Shunt volume can also be estimated by comparing right and left ventricular SV as determined using volumetric analysis. This is, however, generally less precise than MR flow measurement. Estimating shunt volume by comparing right and left ventricular SV is also possible using retrospective ECG-triggered MDCT, but is only reasonable if the examination is necessary because of another indication (e.g., to assess the coronary arteries noninvasively) due to the high radiation exposure. 7



Postoperative and Postinterventional Issues

Repeated imaging is only reasonable within the scope of concurrent defects or if a residual shunt is suspected (e.g., for quantification via MRI flow measurement). Residual defects can often be characterized in older children and adults using TEE, excellent results.



Goals and Relative Value of Diagnostic Imaging

Like in ASD patients, TTE is generally sufficient for assessing VSDs in preoperative diagnostics during childhood, 7 and can be supplemented by TEE. In cases of an inadequate acoustic window—particularly in adults—MRI visualization, MRI shunt quantification, and MRI ventricular volumetry are valuable diagnostic alternatives for cases of VSD, both for primary diagnosis and for follow-up exams.



4.1.3 Atrioventricular Septal Defect

Florentine Gräfe, Ingo Dähnert, Philipp Lurz

Definition

The term “atrioventricular septal defect” (formerly known as “endocardial cushion defect”) encompasses congenital cardiac defects of the structures derived from the embryonic endocardial cushion, meaning from the atrioventricular septum and parts of the mitral and tricuspid valves. They constitute approximately 2–4% of all congenital heart defects. 12 Characteristics of these defects include a joint atrioventricular valve annulus (▶Fig. 4.15) with either a single joint opening or two separate openings, a VSD of variable size, and an ASD I. 13

Fig. 4.15 Various forms of AVSD. Schematic depiction. LA = left atrium LV = left ventricle RA = right atrium RV = right ventricle a The dotted line in the schematic 4-chamber view shows the absent atrioventricular septal and valve portions in a case of complete AVSD. b Top view of a complete AVSD with joint 4-leaflet atrioventricular valve (ostium commune) without distinction between the superior and anterior bridging leaflet (A); B depicts the corresponding posterior and inferior bridging leaflet. c Divided atrioventricular valve in a case of incomplete or partial AVSD. Two functionally separate atrioventricular valves are present, each communicating with one ventricle.

In the most severe anomalies within this group, the primum septum and inlet ventricular septum are completely absent. This means that all chambers of the heart are connected, which was previously known as “total atrioventricular canal” (▶Fig. 4.15).



Note

Trisomy 21 is present in 50% of patients with complete AVSD.



Classification

Signs of all AVSDs:




  • Lack of membranous atrioventricular septum



  • Joint atrioventricular valve annulus with joint or two separate openings



  • Reduced distance between the atrioventricular valve and cardiac apex



  • Superior displacement and lengthening of the LVOT This is also known as a “goose-neck deformity” of the LVOT. In these cases, there is no fibrous aorto-mitral continuity. This stenosis or deformation of the LVOT is most pronounced during diastole, caused by the lack of atrioventricular border normally provided by the membranous septum. 14


The following, most common types will be discussed in detail:




  • Complete AVSD (most common type): A 4-leaflet or 5-leaflet atrioventricular valve (ostium commune) is present (with superior and inferior bridging leaflet), which extends to both ventricles via the septal defect (▶Fig. 4.15). The division of the joined atrioventricular valve via both ventricles can be either balanced (▶Fig. 4.16a, b and, c) or unbalanced (▶Fig. 4.16a, b). This generally leads to hypoplasia in the contralateral ventricle. 15 The superior bridging leaflet may divide near the septum, resulting in a 5-leaflet joint atrioventricular valve. According to Rastelli, balanced, complete AVSD is further subclassified based on the degree of bridging of the anterior or superior bridging leaflet:




    • Type A (70% of cases) with further subdivision of the anterior leaflet into a superior bridging leaflet and a well-developed (right) anterior–superior leaflet; the left tendinous cords insert into the superior margin of the ventricular septum;



    • Type B (15% of cases) with further subdivision of the anterior leaflet into a superior bridging leaflet extending far to the right, and a small anterior–superior leaflet; the left tendinous cords insert into the right papillary muscle;



    • Type C (15% of cases) with no subdivision of the anterior leaflet; the bridging leaflet is large and extends to the right mural leaflet, while the anterior–superior leaflet is absent, resulting in complete bridging (▶Fig. 4.15b).



  • Partial AVSD (second most-common type): ASD I with “cleft formation” in the anterior “mitral leaflet” is present near the atrioventricular valve (known as mitral cleft; ▶Fig. 4.17).



  • Intermediate AVSD (also known as transitional AVSD): The complete atrioventricular canal demonstrates restrictive or functionally closed VSD components caused by portions of the joined atrioventricular valve. 15



  • AVSD: This is a rare, special form of a muscular inlet VSD situated directly inferior to the atrioventricular valves.



  • Isolated mitral valve cleft: This rare form can be considered the least severe form of AVSD with an intact septum.

Fig. 4.16 DORV with concurrent AVSD. Various patients. Ao = Aorta LHL = left hepatic lobe LV = left ventricle PA = pulmonary artery RV = right ventricle a End diastolic cine MRI of an SSFP sequence near the joint atrioventricular valve, short axis. Top view of the opened valve. The joint anterior bridging leaflet (asterisk) can be easily distinguished. b 3-D volume rendering reconstruction of an MRA in a DORV patient. c Complete AVSD: Subcostal, short-axis slice of a TTE for a different patient, with depiction of the opened, butterfly-shaped joint atrioventricular valve (asterisk) in a case of complete atrioventricular canal. d Unbalanced distribution of the joint atrioventricular valve in a case of complete AVSD and HLHS during ventricular filling in diastole, 2-D echo, and color Doppler TTE, apical 4-chamber view. e Color Doppler TTE corresponding to d.
Fig. 4.17 Complete AVSD. LA = left atrium LV = left ventricle RA = right atrium RV = right ventricle a Apical 4-chamber view in TTE. The large arrow indicates the joint atrioventricular valve, while the small circle indicates the VSD components (inlet area), the hatch mark is the ASD-I component (lack of septum primum), and the small arrow is the cleft in the anterior mitral leaflet. b Apical 4-chamber view with color Doppler. Relevant insufficiency of the right (asterisk) and left segment (small circle) of the joint atrioventricular valve visible in color Doppler.


Hemodynamics

The hemodynamics of complete AVSD are characterized by a generally large left–right shunt with pulmonary “recirculation.” The shunt volume at the level of the ventricle thus depends primarily on pulmonary vascular resistance. The VSD is generally large and non-restrictive. Thus, few symptoms are usually present in newborns. With the drop in pulmonary vascular resistance at the age of 6–8 weeks, the left–right shunt increases at the level of the ventricle, which generally leads to early development of global congestive heart failure with pulmonary overflow and left ventricular volume overload (▶Fig. 4.18). If untreated, AVSD can develop into a correspondingly early fixed pulmonary hypertension and triggering of Eisenmenger reaction.

Fig. 4.18 Complete AVSD. LA = left atrium LV = left ventricle RA = right atrium RV = right ventricle a Preoperative a.-p. thoracic X-ray of a newborn with complete AVSD, right aortic arch, persistent left superior vena cava, significantly increased pulmonary perfusion, and global cardiac enlargement. b Suspended a.-p. thoracic X-ray of the same newborn, 3 months after surgery. c Preoperative cine MRI during systole with closed atrioventricular valve (asterisk) in the same newborn. d Preoperative cine MRI during diastole with opened atrioventricular valve. e 3-D reconstruction of the contrast-enhanced MRA of the aorta and pulmonary artery. f 2-D reconstruction of the contrast-enhanced MRA of the aorta and pulmonary artery.

The hemodynamic situation of a partial AVSD is similar to that of an ASD with volume overload occurring in the right ventricle and pulmonary arteries. Furthermore the extent of mitral valve regurgitation determines the hemodynamics. (▶Fig. 4.19 and ▶Table 4.5).

Fig. 4.19 Partial atrioventricular septal defect (ASD I) with absent septum primum and cleft in the anterior mitral leaflet. The asterisk indicates the absent septum primum, and the arrow indicates the cleft in the anterior mitral leaflet. LA = left atrium LV = left ventricle RA = right atrium RV = right ventricle a TTE, apical 4-chamber view. b Apical 4-chamber view with color Doppler: Mitral valve insufficiency is caused by the cleft in the anterior mitral leaflet. c Real-time 3-D echocardiography of a partial atrioventricular septal defect (ASD I). The lack of septum primum is clearly visible (asterisk).


































Table 4.5 Volume load of individual cardiac compartments in a case of complete AVSD.

Cardiovascular compartment


Volume load


Right atrium


++


Right ventricle


++


Pulmonary arteries


++


Pulmonary veins


++


Left atrium


++


Left ventricle


++


Aorta and conduit arteries



Systemic veins




Clinical Issues

In cases of complete AVSD and large left–right shunt, global heart failure generally occurs within a few weeks (▶Fig. 4.18). Within the first year of life, irreversible remodeling of the pulmonary vasculature due to the pulmonary overflow develops. Symptoms are generally less pronounced in cases of partial AVSD, and manifest heart failure rarely develops within the first year of life.



Natural Progression and Indication for Treatment

All AVSDs constitute an indication for surgery, regardless of the type of AVSD. 13



Note

For balanced forms, one should always attempt to enable complete biventricular correction by means of valve reconstruction.


For premature babies, very small children, or patients with concurrent illnesses, pulmonary banding can be performed as a palliative method before surgical correction. The development of a left atrioventricular valve insufficiency with enlargement of the cleft is unfavorable for reconstruction. Thus, the presence of left valve insufficiency (▶Fig. 4.20) constitutes an indication for surgery, regardless of symptoms. In cases of unbalanced AVSDs, univentricular palliation must be performed.

Fig. 4.20 Partial atrioventricular septal defect (ASD I) with absent septum primum and mitral valve insufficiency caused by a cleft in the anterior mitral leaflet. The asterisk indicates the location of the absent septum primum, and the arrow indicates the cleft in the anterior mitral leaflet. AML = anterior mitral leaflet LA = left atrium LV = left ventricle PML = posterior mitral leaflet RA = right atrium RV = right ventricle a 2-D TTE, apical 4-chamber view, without color Doppler. b 2-D TTE, apical 4-chamber view, with color Doppler. c Real-time 3-D echocardiography of the mitral valve with a cleft in the anterior mitral leaflet.


Preoperative Diagnostics

Particularly in cases of complete AVSD, thoracic X-ray (▶Fig. 4.18) indicate significant cardiac enlargement with a prominent pulmonary segment and increased pulmonary vascular markings. These changes are, however, nonspecific. TTE is the initial method of choice, since it allows the atrioventricular valves and bridging leaflet to be depicted via the septal defect. The goose-neck deformity can be visualized in an LVOT cross-section. TEE is the predominant method used for larger children and adults. Cardiac MRI can be used in cases of a limited acoustic window (▶Fig. 4.16 and ▶Fig. 4.18), which also allows shunt volume to be calculated by determining the Q p:Q s ratio. CT plays no role in preinterventional diagnostics. Invasive levocardiography and dextrocardiography also allow pulmonary pressure to be measured, in addition to providing anatomical depictions. They have, however, been largely replaced by echocardiography and MRI in routine preoperative diagnostics, and are performed primarily for late-diagnosed AVSD in order to evaluate pulmonary vascular responsiveness (or after pulmonary banding was performed at a later date, on a case-by-case basis).



Postoperative Issues

The main perioperative and postoperative issues are generally transitory pulmonary vessel reactivity or hypertension, incomplete closure of the defect, atrioventricular blocking, and residual atrioventricular valve insufficiency. If the valves cannot be adequately reconstructed, the atrioventricular valve must be replaced.



Goals and Relative Value of Diagnostic Imaging

As mentioned previously, TTE is sufficient for preoperative diagnostics during childhood (▶Table 4.6). 7 TEE is ideal after surgery and for adults. MRI can be useful in cases of limited acoustic window, either for visualizing concurrent defects or for quantifying shunt volume (▶Table 4.7).
































Table 4.6 Preoperative imaging diagnostics for AVSD.

Imaging methods


Focus


Value


2-D, 3-D TTE




  • Defect size and margins



  • Anatomy and function of the atrioventricular valve



  • Ventricular balance



  • Ventricular function



  • Evaluating LVOT



  • Left–right shunt, qualitative



  • Right heart dilatation



  • Ruling out additional shunts (ASD II, additional VSD, PDA)



  • Ruling out pulmonary and systemic venous anomalies



  • Ruling out associated defects (e.g., aortic coarctation, tetralogy of Fallot, etc.)


+++


2-D, 3-D TEE


see TTE (can only be used in limited circumstances, since most patients are younger than 1 year)


+


Cardiac MRI




  • Quantifying the left–right shunt



  • Quantifying ventricular dilation and function



  • Measuring the defect (phase contrast method)



  • Anatomy of pulmonary and systemic veins


++


(Backup method)


MDCT


Backup method in cases of unclear echocardiographical findings and contraindication against cardiac MRI; may be helpful in cases of pulmonary parenchymatic comorbidity or to prove the existence of concurrent vascular defects, such as anomalous pulmonary venous connections


++


ASD, atrial septal defect; AVSD, atrioventricular septal defect; LVOT, left ventricular outflow tract; MDCT, multidetector computed tomography; MRI, magnetic resonance imaging; PDA, patent ductus arteriosus; TEE, transesophageal echocardiography; TTE, transthoracic echocardiography; VSD, ventricular septal defect.





























Table 4.7 Postoperative imaging diagnostics in a case of AVSD.

Imaging methods


Value


TTE


+++


TEE


++


Cardiac MRI


+++


MDCT


+


Invasive cardiac catheter diagnostics


+


MDCT, multidetector computed tomography; MRI, magnetic resonance imaging; TEE, transesophageal echocardiography; TTE, transthoracic echocardiography.



4.1.4 Patent Ductus Arteriosus

Philipp Beerbaum, Joachim Lotz, Michael Steinmetz

Definition

PDA (also known as patent ductus arteriosus) is the persistence of the fetal connection between the intrapericardial portion of the main pulmonary artery or proximal left pulmonary artery and the extrapericardial descending aorta immediately after the outlet of the left subclavian artery. 12 PDA is a common congenital heart defect, generally concurrent with other congenital defects in 5–10% of patients, though is more frequent in girls than in boys. From an embryological perspective, it develops from the distal portion of the left sixth aortic arch (▶Fig. 4.21c; right aortic arch: ▶Fig. 4.21a). 13 Approximately 60% of cardiac output flows through this arch. This duct normally closes within 72 hours after birth.

Fig. 4.21 Various forms of PDA. Schematic depiction. The asterisks indicate the PDA, and the arrows indicate the direction of blood flow. The course of the PDA is generally conical in the direction of the pulmonary artery. AAo = ascending aorta PA = pulmonary artery a Left aortic arch. b Left aortic arch, bilateral PDA (rare form). c Right aortic arch. d Right aortic arch, bilateral PDA (rare form).


Classification

A clinical distinction is made between the following four forms of PDA 13 :




  • Incidental finding in cases of complex defects (common)



  • Isolated form in premature babies (common; ▶Fig. 4.22)



  • “Compensating” PDA in cases of ductal-dependent heart defects, such as HLHS (ductal-dependent systemic perfusion) or hypoplastic right heart syndrome (ductal-dependent pulmonary perfusion, e.g., in cases of pulmonary atresia)



  • Isolated form in otherwise healthy children (rarer)

Fig. 4.22 PDA. PA = pulmonary artery a 2-D TTE depiction of a PDA (asterisk), short parasternal axis, near the pulmonary artery. b The left–right shunt with flow acceleration can be depicted clearly using color doppler echocardiography.

In very rare cases, a duct aneurysm can occur in a duct with isolated pulmonary (but not aortic) closure (▶Fig. 4.23).

Fig. 4.23 Duct aneurysm. Two-month-old infant with acute respiratory decompensation within the scope of a pulmonary infection. Echocardiography findings raised suspicions of a duct aneurysm. A multi-row CT provided a complete anatomical depiction. The 3-D reconstructions showed a deviation of the trachea to the right and an obstruction in the left main bronchus (blue: air-filled space, reddish: blood-filled or contrast agent-filled vessels; the asterisk indicates the aneurysm). The left pulmonary artery, like the left main bronchus, is also compressed. a Coronal 3-D reconstruction. d Coronal multiplanar 2-D reformat of the data set. b Sagittal 3-D reconstruction. e Sagittal multiplanar 2-D reformat of the data set. c Transverse 3-D reconstruction. f Transverse multiplanar 2-D reformat of the data set.

From pathological and anatomical perspectives, different variants are possible, including those dependent on the presence of a left or right aortic arch. 14 Bilateral PDA can also occur (▶Fig. 4.21b and d), though only in extremely rare cases.



Hemodynamics

An isolated PDA causes a left–right shunt. In these cases, the shunt’s size depends on the diameter of the PDA and the difference between systemic and pulmonary arteriolar resistance. If the PDA diameter is large enough, the left–right shunt generally increases in size during the first months of life. 13 In cases of a particularly large PDA with pressure equalization, if no closure between the aorta and pulmonary artery occurs within the first 6–12 months of life, there is a risk of progressive, often irreversible disorders of the pulmonary resistance vessels accompanied by increased pulmonary vessel resistance. This can lead to shunt reversal (also known as Eisenmenger syndrome). ▶Table 4.8 depicts volume load.



































Table 4.8 Volume load of individual cardiac compartments in a case of PDA.

Cardiovascular compartment


Volume load


Right atrium



Right ventricle



Pulmonary arteries


++


Pulmonary veins


++


Left atrium


++


Left ventricle


++


Aorta (proximal to the PDA)


++


Systemic veins




Clinical Issues

Clinical signs of cardiac failure include a tendency toward infections, sweating, difficulty drinking, and growth disorders, and occur in early infancy solely in cases of extremely large PDA. Generally speaking, the concurrent illnesses remain predominant.



Natural Progression and Indication for Treatment

If untreated, isolated PDA is associated with a 30% mortality rate.



Note

Spontaneous closure after the first weeks of life is extremely rare in mature newborns. Consequently, it is crucial to strive for interventional closure within the first months of life, even in asymptomatic patients.


Treatment must occur as soon as possible for symptomatic newborns. Since indomethacin is no longer effective for mature newborns, it cannot be used in treatment. Rather, a surgery or intervention is needed. Interventional closure using coils, spirals, or a shield system has become the treatment method of choice (▶Fig. 4.24 and ▶Fig. 4.25). Only very large PDAs or duct aneurysms generally require surgical closure (▶Fig. 4.23).

Fig. 4.24 PDA before and after closure with an Amplatzer TM duct occluder. 3.5-year-old girl. AAo = ascending aorta DAo = descending aorta PA = pulmonary artery a Angiogram of a large PDA running conically toward the pulmonary artery (arrow) before intervention. b Angiogram after PDA closure using an AmplatzerTM duct occluder (arrow). c P.-a. X-ray after closure of the PDA, occlusion device enlarged (insert). d Lateral X-ray after closure of the PDA, occlusion device enlarged (insert).
Fig. 4.25 PDA before and after closure with coils. Seven-year-old girl. AAo = ascending aorta DAo = descending aorta a Angiogram of the small PDA (arrow) before intervention. b Angiogram after closure with coils (arrow). c P.-a. X-ray after PDA closure, coils enlarged (arrow and inset). d Lateral X-ray after PDA closure, coils enlarged (arrow and inset).


Preinterventional Diagnostics

Generally speaking, PDA can be visualized clearly using Doppler echocardiography along a high (second-left intercostal area) parasternal short axis. This generally depicts three vessels in proximity to the main pulmonary artery branch: the PDA, and the left and right pulmonary arteries (▶Fig. 4.22). Contrast-enhanced MRA also yields clear images (▶Fig. 4.26a). In cases of a small PDA, a cine MRI through the pulmonary artery and aorta (▶Fig. 4.26b), which allows the PDA to be detected due to MR dephasing caused by flow acceleration of the PDA via the left–right shunt, can also be helpful. MR flow measurement can be used for noninvasive shunt quantification in the ascending aorta, pulmonary artery, or distal to the PDA in the right and left pulmonary arteries. MDCT, likewise, can be used as a backup method (▶Fig. 4.23).

Fig. 4.26 Secondary PDA. Contrast-enhanced MRA with ancillary finding of a small PDA (a, asterisk) in a 12-year-old boy who had received an MRI to depict the aortic arch based on suspicion of an aortic coarctation. Two shunts were identified: a small, silent PDA which was also detected during the cine MRI due to dephasing caused by flow acceleration (b, arrows), and a small, perimembranous VSD (▶Fig. 4.11). a Contrast-enhanced MRA. b Cine MRI using SSFP sequences, angled parasagittal section.


Postoperative and Postinterventional Issues

A residual shunt can occur after surgical or interventional closure. Generally speaking, this can be evaluated via echocardiography. MRI using phase contrast technology is an alternative for quantifying any potential residual shunt.



Goals and Relative Value of Diagnostic Imaging

TTE is generally sufficient during childhood (▶Table 4.9 and ▶Table 4.10). 7




































Table 4.9 Preinterventional imaging diagnostics in a case of PDA.

Imaging methods


Focus


Value


2-D TTE




  • Size and shape



  • Left–right shunt, qualitative



  • Dilatation of the aorta and pulmonary arteries



  • Ruling out concurrent defects


+++


2-D TEE


see TTE


++


Cardiac MRI




  • Quantifying the left–right shunt



  • Quantifying ventricular dilatation and function



  • Measuring the defect (phase contrast method)



  • Anatomy of the aorta and pulmonary arteries


++


(Backup method)


MDCT


Backup method in cases of unclear echocardiographical findings, where cardiac MRI is contraindicated


+


Invasive (diagnostic) cardiac catheter tests




  • Measuring pressure and resistance (if indicated), pharmacological testing



  • In rare cases: invasive measurement of diastolic left ventricular functional parameters (e.g., left ventricular end diastolic pressure) in cases of suspected elevated risk of pulmonary edema after ASD closure



  • Ruling out pulmonary and systemic venous anomalies


+++


(in cases of pulmonary hypertonia and suspected left ventricular restriction)


ASD, atrial septal defect; MDCT, multidetector computed tomography; MRI, magnetic resonance imaging; TEE, transesophageal echocardiography; TTE, transthoracic echocardiography.





























Table 4.10 Postinterventional imaging diagnostics in a case of PDA.

Imaging methods


Value


TTE


+++


TEE


++


Cardiac MRI


++


MDCT


(+)


Invasive cardiac catheter diagnostics


+++


MDCT, multidetector computed tomography; MRI, magnetic resonance imaging; TEE, transesophageal echocardiography; TTE, transthoracic echocardiography.



4.1.5 Aortopulmonary Window (Aortopulmonary Septal Defect)

Florentine Gräfe, Ingo Dähnert, Philipp Lurz

Definition

APSD—also known as “aortopulmonary window,” “aortopulmonary septal defect,” and “aortopulmonary fistula”—is a very rare defect caused by an embryonic defect in the aortopulmonary septum. It can occur in isolation or concurrent with other congenital heart defects, such as coronary anomalies (in 50–66% of cases). This defect causes a connection of varying size between the ascending aorta and pulmonary artery (▶Fig. 4.27). In these cases, two separate valve rings for the aortic and pulmonary valve are always present.

Fig. 4.27 Main types of APSD. Schematic depiction. a Proximal (more common). b Distal (less common) between the ascending aorta and right pulmonary artery.


Classification

A rough distinction can be made between the proximal and distal types 13 :




  • Proximal defect (62% of APSDs; ▶Fig. 4.28, ▶Fig. 4.29, and ▶Fig. 4.30; also ▶Fig. 4.27a): The APSD is located on the dorsal-lateral or posterior wall of the ascending aorta or the anterior-lateral wall of the pulmonary artery, meaning that the defect is directly cranial to the aortic and pulmonary valves.



  • Distal defect (38% of APSDs; ▶Fig. 4.31; also ▶Fig. 4.27b): The APSD is located near the anterior wall of the right pulmonary artery. Very large defects may appear to be right pulmonary arterial outlets from the ascending aorta (hemitruncus). Unlike hemitruncus, however, a connection remains between the right pulmonary artery and the pulmonary arterial bifurcation.

Fig. 4.28 Proximal APSD (asterisk). Twenty-three-year-old man. Ao = aorta PA = pulmonary artery a MIP reconstruction of a contrast-enhanced MRA. b Cine MRI with SSFP sequences, coronal orientation. c Cine MRI with SSFP sequences, transverse orientation. d ECG-triggered transverse black blood SE sequence.
Fig. 4.29 Proximal APSD. Patient with large APSD (asterisk), pulmonary hypertonia, and bidirectional shunt. Ao = aorta; PA = pulmonary artery a MRI with 3-D reconstruction of a contrast-enhanced MRA. b SSFP sequences, coronal slice near the APSD, depicting the very large defect. c Corresponding axial slice.
Fig. 4.30 Proximal APSD. Each asterisk indicates an APSD. Ao = aorta LV = left ventricle PA = pulmonary artery RA = right atrium RV = right ventricle a Subcostal 2-D echo slice depicting the great arteries. b The left–right shunt is visible via the APSD as the red area (asterisk) on the color Doppler image.
Fig. 4.31 Distal APSD. Each arrow indicates the position of an APSD. Doppler echocardiography exams, various patients. Ao = aorta LPA = left pulmonary artery PA = pulmonary artery RPA = right pulmonary artery a 2-D TTE image of the great vessels, short-axis parasternal view. b Great vessels, short-axis parasternal view, without color Doppler. c Great vessels, short-axis parasternal view, with color Doppler (the same patient as in b). The left–right shunt via the APSD is depicted in red on the image. d 2-D TTE image, parasternal short axis, without color Doppler. e 2-D TTE image, parasternal short axis, with color Doppler (the same patient as in d). The left–right shunt via the APSD is depicted in red on the image.


Hemodynamics

Generally speaking, the APSD is large, meaning that it does not lead to pressure separation (restriction). In this respect, the APSD bears a pathophysiological resemblance to a large, window-like PDA. Nevertheless, it generally leads to earlier occurrence of heart failure (▶Fig. 4.32), similar to cases of small children with large VSDs. If untreated, large APSDs can lead to fixed pulmonary hypertension and the Eisenmenger reaction. Volume load in cases of APSD is listed in ▶Table 4.11.

Fig. 4.32 APSD. Thoracic X-ray of a 4-week-old infant. Significantly enlarged heart, more pronounced on the left side. Considerable pulmonary hyperperfusion.


































Table 4.11 Volume load for individual cardiac compartments in a case of complete APSD.

Cardiovascular compartment


Volume load


Right atrium



Right ventricle



Pulmonary arteries


++


Pulmonary veins


++


Left atrium


++


Left ventricle


++


Aorta and conduit arteries



Systemic veins




Clinical Issues

Within the scope of pronounced left–right shunt with pulmonary overflowing, children generally exhibit a failure to thrive, recurrent pulmonary infections, and the clinical picture of heart failure (▶Fig. 4.32).



Natural Progression and Indication for Treatment

Due to the poor prognosis for untreated defects (with the exception of small shunts), diagnosis is generally a sufficient indication for surgery. 13 A contraindication for surgical treatment only exists in cases where the Eisenmenger reaction has already occurred. For smaller defects, surgeons can also strive for interventional closure.



Preinterventional and Preoperative Diagnostics

In general, TTE is adequate (▶Fig. 4.30 and ▶Fig. 4.31) for diagnostic purposes in children, especially in cases of proximal defects (▶Fig. 4.30). In cases of distal defects, visualization can present difficulties. A cross-sectional imaging procedure, ideally an MRI, can be useful in such situations (▶Fig. 4.28 and ▶Fig. 4.29). In addition to visualization, MRI also allows absolute shunt quantification. MDCT is also, fundamentally, appropriate for visualizing defects, particularly if additional coronary and/or aortic anomalies are present or suspected.



Postoperative and Postinterventional Issues

Post-surgical prognosis is generally determined by concurrent defects and the degree of pulmonary hypertension. Similar to the closure of small defects, if the APSD is surgically treated within the first year of life—namely, before the onset of irreversible pulmonary changes—life expectancy is fully unaffected. 12



Goals and Relative Value of Diagnostic Imaging

TTE is generally sufficient during childhood (▶Table 4.12 and ▶Table 4.13). 7 Fluoroscopy can also be used to monitor peri-interventional catheter placement (▶Fig. 4.33).

Fig. 4.33 APSD. A.–p. fluoroscopy of an adult male with APSD originating in the right coronary sinus (arrow). The pigtail catheter is positioned within the left coronary sinus of the aortic root (asterisk). The pulmonary root superior to the APSD is colorless (dotted line).



































Table 4.12 Preinterventional or preoperative imaging diagnostics in cases of APSD.

Preinterventional/preoperative imaging methods for APSD


Focus


Value


2-D, 3-D TTE




  • Defect size and position



  • Shunt, qualitative



  • Left heart dilation



  • Assessing right ventricular and pulmonary arterial pressure



  • Ruling out additional shunts



  • Assessing coronary anatomy



  • Ruling out pulmonary and systemic venous anomalies


+++


2-D, 3-D TEE


Refer to TTE (primarily helpful for proximal defects; can only be used in limited cases, since most patients are less than 1 year)


+


Cardiac MRI




  • Quantifying the left–right shunt



  • Quantifying ventricular dilatation and function



  • Measuring the defect (phase contrast method)



  • Anatomy of pulmonary and systemic veins


+++


(Backup method)


MDCT


Backup method in cases of unclear echocardiographical findings and contraindication against cardiac MRI; may be helpful in cases of pulmonary parenchymatic comorbidity or to prove the existence of concurrent vascular defects, such as anomalous pulmonary venous connections


(+)


Invasive (diagnostic) cardiac catheter tests




  • Measuring pressure and resistance (if indicated) and pharmacological testing of pulmonary vascular reactivity



  • Defect position and size in cases of distal defects



  • Ruling out pulmonary and systemic venous anomalies


++


(in cases of pulmonary hypertonia)


MDCT, multidetector computed tomography; MRI, magnetic resonance imaging; TEE, transesophageal echocardiography; TTE, transthoracic echocardiography.





























Table 4.13 Postinterventional or postoperative imaging diagnostics in cases of APSD.

Imaging methods


Value


TTE


+++


TEE


+


Cardiac MRI


+++


MDCT


+


Invasive cardiac catheter diagnostics


++


MDCT, multidetector computed tomography; MRI, magnetic resonance imaging; TEE, transesophageal echocardiography; TTE, transthoracic echocardiography.



4.2 Right-Side Defects



4.2.1 Pulmonary Valve Stenosis

Samir Sarikouch, Matthias Grothoff, Erich Sorantin

Definition

Isolated pulmonary valve stenosis is the most common form of narrowed RVOT in cases of normal aortic origins (occurring in 80% of cases). It constitutes 6–8% of all congenital heart defects. 16 There are various clinical progressions based on the degree of stenosis, which are generally caused by adhesion of the tricuspid or bicuspid semilunar valves’ commissures (▶Fig. 4.34).

Fig. 4.34 Isolated valvular or infundibular pulmonary stenosis. Schematic depiction. Note the thickened portions of the pulmonary valve forming a dome-like shape, and the narrowed RVOT. LA = left atrium PA = pulmonary artery RA = right atrium RV = right ventricle RVOT = right ventricular outflow tract


Natural Progression and Clinical Issues

If a moderate-to-severe pulmonary valve stenosis (▶Table 4.15) is present, blood flow into the lungs is reduced, resulting in the development of cyanosis and ductal-dependent pulmonary blood flow. This clinical picture is then described as “critical pulmonary stenosis.” In these cases, hypoplasia of the corresponding hypertrophied right ventricle is often also present.


In contrast, if only a minor degree of stenosis is present, diagnosis often first occurs based on systolic heart murmur or when signs of right ventricular heart failure arise. Fully unremarkable clinical progressions can also occur, meaning corresponding diagnostics only occur based on pathological ECG findings.



Treatment Options and Preinterventional Diagnostics

Nowadays, interventional catheter therapy using balloon valvuloplasty (▶Fig. 4.36) is performed in the vast majority of cases of symptomatic, isolated pulmonary valve stenosis, which can generally be quantified clearly via Doppler echocardiography (▶Fig. 4.35; ▶Table 4.15)—meaning starting at a gradient of more than 3–40 mmHg in clinical practice. This can be performed even in newborns at very low risk. Surgical treatment is only used in very rare cases, often after unsuccessful balloon dilatation or in cases of pronounced dysplasia of the valve apparatus and/or associated subvalvular or supravalvular narrowing. This operation is often combined with narrow transannular patch plasty. 17

Fig. 4.35 Determining pressure gradient via the pulmonary valve. PV = pulmonary valve LA = left atrium LCC = left coronary aortic leaflet NCC = non-coronary aortic leaflet PA = pulmonary artery RA = right atrium RCC = right coronary aortic leaflet RVOT = right ventricular outflow tract TV = tricuspid valve a Schematic depiction of an echocardiographical doppler view (red line through the pulmonary valve). The position of the valvular stenosis and the pressure gradient can be determined via the pulmonary valve using PW Doppler. b Echocardiographical doppler view in a male patient with high-grade stenosis of the pulmonary valve and a maximum measured flow velocity of 4.5 m/s. According to the Bernoulli equation, this results in a maximum estimated instantaneous pressure gradient of 79 mmHg via the pulmonary valve.


Postoperative and Postinterventional Issues

Patients with pulmonary valve stenosis who were initially treated successfully using balloon valvuloplasty may develop new gradients or possess a residual gradient that must be monitored to assess the need for additional treatment. A residual peak gradient of less than 20–30 mmHg is generally well tolerated. 18 The prominent pulmonary segment, often first identifiable in the p.-a. thoracic X-ray, frequently remains present even after successful treatment (▶Fig. 4.37).


Pulmonary valve insufficiency and the corresponding right ventricular volume overload occasionally occur after balloon dilatation. Much more commonly, they occur after surgical treatment. Consecutive right ventricular dilatation, which patients may tolerate well for years (▶Fig. 4.37b and ▶Fig. 4.45), can later lead to progressive tricuspid valve insufficiency and electrical instability, resulting in ventricular arrhythmia and right ventricular heart failure.



Note

The main objective of imaging is determining the timing of the interventional or surgical pulmonary valve replacement, which should occur based on objective progression data.



Goals and Relative Value of Diagnostic Imaging

Both initial diagnosis of a congenital pulmonary valve stenosis and the indication for interventional or surgical treatment can generally be depicted very well using doppler echocardiography (▶Fig. 4.35). MRI and MDCT play a large role, above all during postsurgical and postinterventional follow-up care. MRI is the method of choice for assessing right ventricular function, volume, and mass (▶Table 4.14). It is also suitable for absolute quantification of pulmonary valve insufficiency (▶Fig. 4.37) by means of calculating the regurgitation fraction:




























































































Table 4.14 Focus of imaging diagnostics with the value of individual procedures for cases of pulmonary valve stenosis.

Clinical situation


Common diagnostic tasks


Imaging method of choice in light of practical clinical perspectives


Value of imaging method


Presurgical/preinterventional


Ductal-dependent pulmonary blood flow


Duct size, right ventricular size, pulmonary valve diameter


Echocardiography


+++


MRI


++


MDCT


+


Angiography/intervention


++


Antegrade pulmonary blood flow


Gradient through the pulmonary valve, right ventricular size, pulmonary valve diameter, ASD


Echocardiography


+++


MRI


++


MDCT


+


Angiography/intervention


++


Postsurgical/postinterventional


Minor residual stenosis, minor insufficiency


Right ventricular function


Echocardiography


++


MRI


+++


MDCT


+


Angiography/intervention



Relevant residual stenosis


Right ventricular hypertrophy, assessing the degree of stenosis (primarily in cases of concurrent supravalvular stenosis)


Echocardiography


+++


MRI


++


MDCT


+


Angiography/intervention


++


Relevant insufficiency


Quantifying pulmonary insufficiency, right ventricular size and function


Echocardiography


++


MRI


+++


MDCT


+


Angiography/intervention



ASD, atrial septal defect; MDCT, multidetector computed tomography; MRI, magnetic resonance imaging.


where




  • RF = regurgitation fraction in %



  • Antegrade and retrograde flow are indicated in ml.


MDCT allows concurrent changes to pulmonary structure and vascular changes caused by CTA (such as MAPCA and peripheral pulmonary stenosis) to be depicted (▶Fig. 4.46). Vascular changes can also be depicted clearly using contrast-enhanced MRA (▶Fig. 4.38). Dynamic visualization of the valve can also be performed via MDCT when using retrospective gating. Due to high radiation exposure, however, this method only comes into play in cases of inadequate acoustic windows and contraindications for MRI diagnostics. 7 MRI, in contrast, can be used as an alternative to echocardiography, while CT can only be used in certain cases, e.g., to assess a lung parenchyma. Likewise, a valve stenosis can be quantified noninvasively via Doppler echocardiography, MRI flow measurement, or valve planimetry (▶Table 4.15; also ▶Fig. 4.37).








































Table 4.15 Graduation of the pulmonary valve stenosis via invasive cardiac catheter pressure measurement, Doppler echocardiography, MR flow measurement, or determination of valve opening area. 7 , 13

Parameter


Degree of severity of pulmonary valve stenosis


Minor (I)


Moderate (II)


Significant (III)


Severe (IV)


v max (m/s)


< 2.0


2.0–3.5


3.5–4.5


> 4.5


p max (mmHg)


< 25


25–49


50–79


> 80


Valve opening area (cm2/m2 body surface area)


1.00–2.00


< 1.00


< 0.50


< 0.25


Δpmax, maximum pressure gradient; vmax, maximum flow velocity.



4.2.2 Tetralogy of Fallot

Samir Sarikouch, Matthias Grothoff, Erich Sorantin

Definition

In 1888, Etienne-Louis Arthur Fallot described a combination of pulmonary stenosis, large VSD, and right displacement of the aorta with concentric right ventricular hypertrophy (▶Fig. 4.39). 19 Nowadays, anterior cephalic malrotation of the outlet septum is considered the main cause of this most common cyanotic defect, comprising up to 9% of all heart defects in international literature, and 2.5% of all cardiac defects in Germany in the 2006-07 year. 16



Natural Progression and Clinical Issues

Similar to isolated pulmonary valve stenosis, the degree of stenosis of the RVOT determines the clinical symptoms, which can range from severe cyanosis with ductal-dependent pulmonary perfusion to the clinical picture of “pink Fallot.” The commonly present infundibular (i.e., muscular) portion of an outflow tract stenosis (▶Fig. 4.40) can lead to intermittent bouts of cyanosis, even in cases of minor or moderate pulmonary stenosis. The pulmonary arteries also demonstrate variable pathology. Stenoses, particularly those of the left pulmonary artery, are common and can lead to side differences in pulmonary perfusion (▶Fig. 4.41). Hyperperfusion can also occur in certain pulmonary segments due to aortopulmonary collaterals (▶Fig. 4.42). 20



Treatment Options and Preinterventional Diagnostics

In cases of ductal-dependent pulmonary blood flow, catheter interventional procedures using balloon dilatation of valvular stenosis portions can be used (▶Fig. 4.36). If cyanotic newborns cannot be treated using catheter procedures, either an aortopulmonary shunt is placed or early correction is performed. In cases of elective correction, generally during the first 6 months of life, the VSD is closed and the outflow tract stenosis is addressed by resecting the obstructing bundle of muscle in conjunction with a valvuloplasty. This procedure is commonly supplemented by a transannular patch due to the often-narrow valve rings. Like in cases of isolated pulmonary valve stenosis, preinterventional diagnostics fall within the domain of Doppler echocardiography (▶Fig. 4.35 and ▶Fig. 4.39d).

Fig. 4.36 Cardiac catheterization in a case of valvular or infundibular pulmonary stenosis. a Direct cardiac catheterization in an underweight newborn with valvular or infundibular pulmonary stenosis within the scope of tetralogy of Fallot and recurrent hypoxic episodes, depicting a high-grade infundibular pulmonary stenosis (arrow). b The balloon valvuloplasty with stent placement in the RVOT prevented further cyanosis until the final corrective surgery was performed. This figure shows stent dilatation in a.-p projection. c The lateral projection after stent placement shows good preliminary results in the follow-up angiogram. Insert: enlarged view of stent.
Fig. 4.37 Condition after a commissurotomy of a pulmonary valve stenosis. Various depictions of a 14-year-old girl’s condition after a commissurotomy of a pulmonary valve stenosis during her first year of life. Now, only residual pulmonary valve insufficiency remains. Using MRI flow measurement in the “in-plane” (along the course of the vessel; d, e) and “through-plane” (perpendicular to the course of the vessel or cranial and parallel to the valve level; d, e, red line, cross-sectional plane for g–i) phase contrast techniques, pulmonary valve insufficiency can be quantified precisely as a regurgitation fraction in ml or in % (f; 34% in this case). Ao = aorta LV = left ventricle PA = pulmonary artery RA = right atrium RV = right ventricle SVC = superior vena cava a P.-a. X-ray. The prominent pulmonary segment is still visible after surgery (arrow). b The transverse SSFP cine MRI shows an enlarged right ventricle and a flattened interventricular septum resulting from volume overload (115 ml/m2) c The dilated pulmonary arteries can be recognized clearly in the lateral MIP reconstruction of a contrast-enhanced pulmonary MRA. d Determining the sectional planes for g–i (systole) in the magnitude image of an in-plane image of the flow-sensitive GE sequence, in an angulated sagittal plane, through the pulmonary artery. e Determining the sectional planes for g–i (diastole) in the magnitude image of an in-plane image of the flow-sensitive GE sequence, in an angulated sagittal plane, through the pulmonary artery. The arrow indicates early diastolic dephasing through the pulmonary valve due to pulmonary valve insufficiency. f Flow curve through the pulmonary valve. Red indicates antegrade flow during systole, while blue indicates retrograde flow during diastole. The depicted interval corresponds to an RR interval of 882 ms, recorded based on heart rate. g Phase image of the flow-sensitive GE sequence during systole. Cranial flow is light in color, while caudal flow is dark. h Phase image of the flow-sensitive GE sequence during diastole. Retrograde flow in the pulmonary artery (caused by pulmonary valve insufficiency) is depicted in a dark color. i Anatomical magnitude image of the flow-sensitive GE sequence during systole. Note the tricuspid pulmonary valve’s opening during systole.


Postoperative and Postinterventional Issues

During surgical correction of RVOT stenosis, a dilemma arises between moderate widening of the outflow tract with the risk of a relevant residual gradient, and considerable expansion using a patch (▶Fig. 4.43 and ▶Fig. 4.44), which carries the risk of significant pulmonary valve insufficiency. Higher perioperative mortality in cases of significant residual gradients leads to increased use of transannular patches. Similar to isolated pulmonary valve stenosis, right ventricular volume overload is generally well tolerated, sometimes for decades. The timing for a secondary pulmonary valve replacement has changed in recent years due to multiple studies for adult patients, where no regression of a right ventricular dilatation beyond 170–180 ml/m2 could be proven. 21 In cases of right ventricular dilatation, a pronounced tricuspid valve insufficiency may develop, which will then require further treatment (▶Fig. 4.45).

Fig. 4.38 MAPCA. DAo = descending aorta a 3-D depiction of multiple MAPCAs from a contrast-enhanced MRA, dorsal view, in a 32-year-old male patient. A particularly large aortopulmonary collateral from the descending aorta to the right lung is marked with an arrow. b Axial multiplanar reformat of the large MAPCA to the right lung, in the same patient (arrow).

Pulmonary arterial stenoses are common after surgery (▶Fig. 4.40, ▶Fig. 4.41, and ▶Fig. 4.43), and the use of foreign materials during primary correction renders them more common. Today, they remain within the domain of catheter interventional treatment. They are generally well managed via balloon dilatation and stent implantation. 20 , 22

Fig. 4.39 Tetralogy of Fallot. Ao = aorta AoV = aortic valve LA = left atrium LV = left ventricle MV = mitral valve PA = pulmonary artery PV = pulmonary valve RA = right atrium RV = right ventricle TV = tricuspid valve VSD = ventricular septal defect a The schematic depiction of tetralogy of Fallot shows the aorta “overriding” the VSD, the pulmonary infundibular or pulmonary valve stenosis, and right ventricular hypertrophy. The trabecular segment of the right ventricle extends to the VSD. b Schematic depiction of tetralogy of Fallot, view from the right ventricle, with color-coded blood flow (blue = deoxygenated, red = oxygenated, purple = mixed venous blood). c Schematic depiction of tetralogy of Fallot in the indicated 4-chamber view. d In the 2-D TTE, the aorta “overriding” the VSD (asterisk) is clearly visible seen along the parasternal long axis before surgical correction in a patient with tetralogy of Fallot.
Fig. 4.40 Surgically corrected tetralogy of Fallot. 3-D MIP reconstruction from a contrast-enhanced MRA of a patient after surgical correction of tetralogy of Fallot using a valve-equipped conduit in the form of a prosthesis from the RVOT to the pulmonary bifurcation. The original subvalvular or infundibular pulmonary stenosis (a, thick arrow) is still visible in RAO projection. Multiple peripheral pulmonary stenoses (a–c, thin arrows) can also be seen in a.-p (b) and in LAO projection (c). RV = right ventricle a RAO projection. b A.-p. projection. c LAO projection.


Goals and Relative Value of Diagnostic Imaging

Like in cases of isolated pulmonary valve stenosis, Doppler echocardiography is the initial method of choice for diagnostic purposes and for determining indication for surgery (▶Table 4.16). In cases where the peripheral pulmonary arterial branches can only be assessed on a limited basis through the pulmonary parenchyma or where MAPCAs are present, MRI and MDCT imaging procedures using contrast-enhanced angiography (▶Fig. 4.46; also ▶Fig. 4.38 and ▶Fig. 4.42) can be helpful before electing to use an invasive cardiac catheter. The main focus of tomographic procedures, especially MRI, is postoperative use. Monitoring progression requires consistent assessment of right ventricular function, volume, and muscle mass with respect to residual stenosis and pulmonary valve insufficiency (▶Fig. 4.37) in order to be able to determine indications for additional surgery. In the meantime, specific reference values for the expected ventricular sizes and dimensions of the great vessels (in both cases, based on the patient’s age and sex) are available for these heart defects. 23 25

Fig. 4.41 Surgically corrected tetralogy of Fallot. a 3-D MIP reconstruction from a contrast-enhanced MRA in a 9-year-old female patient after surgical correction of tetralogy of Fallot, with left pulmonary artery occlusion. b The axial MR pulmonary perfusion image of the bolus track at the start of the contrast-enhanced MRA shows a lack of left-side pulmonary perfusion.
Fig. 4.42 Uncorrected tetralogy of Fallot. 3-D volume rendering reconstruction from a contrast-enhanced MRA in a 54-year-old woman with uncorrected tetralogy of Fallot, pulmonary atresia, and pulmonary perfusion exclusively via pronounced MAPCAs. a A.-p. projection. b Dorsal projection. c A.-p. projection after “virtual” removal of the ventricle and the ascending aorta in post-processing.
Fig. 4.43 Condition after corrective surgery for a case of tetralogy of Fallot in adulthood, and implantation of an ICD. Fifty-six-year-old male patient. The asterisk indicates the position of the ICD that was implanted due to ventricular tachycardia. Originally, a Blalock–Taussig shunt was placed. Ao = aorta PA = pulmonary artery RV = right ventricle RVOT = right ventricular outflow tract a Angulated coronal reconstruction (RAO equivalent) through the dilated RVOT from an ECG-triggered MDCT data set (320 rows). b The transverse images depict significant stenosis of the right pulmonary artery. c 3-D volume rendering of the same data set, cranial view. Significant RVOT expansion after patch placement and high-grade stenosis of the left pulmonary artery (arrow). The reconstructions (c, d) each occurred during diastole in the 75% RR interval. d Corresponding images for c, ventral view.
Fig. 4.44 High-grade restenosis of a xenograft in the pulmonary position after correcting tetralogy of Fallot. Nineteen-year-old female patient with high-grade residual stenosis of a xenograft in the pulmonary position, after surgical correction of tetralogy of Fallot, before a planned transcatheter pulmonary valve replacement (Melody valve). Magnitude and phase images of a flow-sensitive MRI GE sequence (c–f) show flow acceleration via the stenosed pulmonary valve to a maximum of 4 m/s, in terms of a maximum estimated instantaneous pressure gradient of 64 mmHg and a holodiastolic regurgitation fraction of 39%. RVOT = right ventricular outflow tract a Right ventriculography (RAO: right ventricular ejection fraction = 42%, right ventricular EDV = 126 ml/m2). b 3-D MIP of a contrast-enhanced MRA. Pronounced RVOT enlargement after patch plasty. c Magnitude image of a flow-sensitive MRI GE sequence through the RVOT and the pulmonary artery of the same patient during systole. d Phase image of a flow-sensitive MRI GE sequence through the RVOT and pulmonary artery of the same patient during systole. e Magnitude image of a flow-sensitive MRI GE sequence through the RVOT and pulmonary artery of the same patient during diastole. f The phase image of a flow-sensitive MRI GE sequence through the RVOT and pulmonary artery of the same patient during diastole clearly depicts diastolic regurgitation. g P.-a. thoracic X-ray before pulmonary valve implantation. h Lateral thoracic X-ray before pulmonary valve implantation. i P.-a. thoracic X-ray after transcatheter pulmonary valve implantation. j Lateral thoracic X-ray after transcatheter pulmonary valve implantation.



























































































Table 4.16 Focus of imaging diagnostics with the value of individual procedures for tetralogy of Fallot.

Clinical situation


Common diagnostic tasks


Imaging method of choice


Value of imaging method


Preoperative (generally infants)


Ductal-dependent pulmonary blood flow


Gradient and morphology of pulmonary stenosis (infundibular, valvular, supravalvular), aortopulmonary collaterals


Echocardiography


+++


MRI


++


MDCT


++


Angiography/intervention


++


Antegrade pulmonary blood flow


Pulmonary stenosis gradient and morphology (infundibular, valvular, supravalvular), dimensions of the left and right pulmonary arteries, aortopulmonary collaterals


Echocardiography


+++


MRI


+++


MDCT


++


Angiography/intervention


+


Postoperative


Minor residual stenosis, minor insufficiency, residual shunt via the VSD


Morphological assessment of supravalvular stenoses, right ventricular function, shunt quantification


Echocardiography


++


MRI


+++


MDCT


+


Angiography/intervention


+


Relevant residual stenosis


Right ventricular hypertrophy


Echocardiography


+++


MRI


++


CT


+


Angiography/intervention


++


Relevant insufficiency


Right ventricular size and function, pulmonary insufficiency, tricuspid valve insufficiency


Echocardiography


++


MRI


+++


CT


+


Angiography/intervention


+


CT, computed tomography; MDCT, multidetector computed tomography; MRI, magnetic resonance imaging; VSD, ventricular septal defect.


Newer interventional procedures, such as transcatheter valve replacement (▶Fig. 4.44), require precise preinterventional assessment of the ventricle that underwent previous surgical treatment, RVOT, valve annulus, and the pulmonary valve, itself. This can occur via MRI or MDCT (▶Fig. 4.43), especially if there is a contraindication against MRI (e.g., if an implantable cardioverter defibrillator [ICD] is present).

Fig. 4.45 Condition after tricuspid valve replacement, 30 years after surgical correction of tetralogy of Fallot. Fifty-one-year-old male patient after mechanical tricuspid valve replacement. Significantly enlarged right atrium and right ventricle. LA = left atrium LV = left ventricle RA = right atrium RV = right ventricle a P.-a. thoracic X-ray. b Lateral thoracic X-ray. c Transverse reconstructions from an ECG-triggered MDCT data set (diastolic reconstruction in the 75% RR interval). d Corresponding angulated sagittal reconstruction near the tricuspid valve replacement. The valve segments opened during diastole are clearly visible.


4.2.3 Pulmonary Atresia with Ventricular Septal Defect and Intact Ventricular Septum

Samir Sarikouch, Matthias Grothoff, Erich Sorantin

Definition

Pulmonary atresia with VSD (approx. 1% of all heart defects 16 ) can be described as an extreme variant of tetralogy of Fallot, in which complete closure of the RVOT to the lungs occurs (▶Fig. 4.42 and ▶Fig. 4.46). The aorta is displaced similarly to cases of tetralogy of Fallot, and the VSD is generally large. Pulmonary perfusion occurs via the ductus arteriosus or multiple aortopulmonary collaterals, the MAPCAs. 26


In cases of pulmonary atresia with intact ventricular septum (approx. 0.5–1.0% of all heart defects 16 ), complete closure of the RVOT to the lungs also occurs. The blood in the right ventricle cannot drain through a ventricular septal defect. Thus, significant hypoplasia of the right ventricle’s greatly thickened walls often occurs in this situation (▶Fig. 4.47). Associated anomalies of the tricuspid valve are common. Connections may also arise between the right ventricle (which is subjected to significant pressure overload) and the coronary arteries, which further complicates surgical treatment. 27 In both situations, additional atrial septal defects are often present.

Fig. 4.46 Tetralogy of Fallot and pulmonary atresia. 3-D volume rendering from a non ECG-triggered MDCT data set (acquired using 64 rows) in a newborn with heterotaxia and tetralogy of Fallot accompanied by pulmonary atresia. PDA = patent ductus arteriosus a The a.-p depiction shows the left aortic arch and a lack of RVOT. b Left-lateral projection with a PDA. c Native peripheral pulmonary vascular system, posterior view (after removing the spinal column and ribs).


Natural Progression and Clinical Issues

The lack of antegrade pulmonary perfusion is common in both types of heart defects. Clinical status after birth is determined primarily based on the type of pulmonary perfusion and the location of the central pulmonary arteries. If a fairly normal pulmonary arterial system is present and pulmonary perfusion occurs mostly via the ductus arteriosus, the duct is held open using prostaglandin. If, as is generally the case, multifocal pulmonary circulation occurs via individual MAPCAs (▶Fig. 4.42), attempts to hold open the ductus arteriosus are generally unsuccessful. This causes differing pulmonary circulation in the different pulmonary lobes, resulting in the development of heart failure and increased resistance in these pathological vessels.



Note

In cases of pulmonary atresia with intact ventricular septum (▶Fig. 4.47a), an adequate atrial shunt is of great importance, since this is the only way to reintroduce systemic blood into circulation.



Treatment Options and Preinterventional Diagnostics

For both types of heart defects, if a membranous pulmonary atresia is present, there is a possibility of antegrade, catheter interventional or surgical opening, provided that the central pulmonary arteries are normal. The presence of a right ventricle that is adequately large or capable of development is a prerequisite for these procedures. Particularly for cases of pulmonary atresia with intact ventricular septum, pronounced hypoplasia in the right ventricle renders biventricular correction impossible. As a result, treatment must take the form of definitive palliation in the sense of Fontan circulation. The sections on HLHS and univentricular heart address this topic in greater detail. If an adequately large ventricle is present, biventricular correction is desirable. If multiple MAPCAs are present, they must be combined surgically (i.e., unifocalized) in order to ensure antegrade pulmonary perfusion after implanting a conduit (valve-equipped [▶Fig. 4.48] or valve-less) and in order to be able to close the VSD.

Fig. 4.47 Pulmonary atresia without VSD. Schematic depiction. Ao = aorta LV = left ventricle RV = right ventricle a Hypoplastic right ventricle with regurgitation via the tricuspid valve and a large ASD (asterisk). b Pulmonary atresia and filling by mixed venous blood through a PDA.


Postoperative and Postinterventional Issues

Stenosis of the consolidated pulmonary arteries often occurs after unifocalization and biventricular correction. In some cases, certain pulmonary areas receive both antegrade perfusion and perfusion from the residual MAPCAs (i.e., double perfusion). Individual pulmonary segments can only be supplied with blood by aortopulmonary collaterals, which elevates the risk of developing pulmonary arterial hypertonia in these areas. 28


After biventricular correction, cardiac function for the right chamber is determined by frequent pressure elevation due to the newly created central pulmonary vascular system, the sometimes abnormally formed peripheral pulmonary vascular system, and the function of the implanted conduit. The persistence of significant MAPCAs can cause volume overload in the left ventricle.



Goals and Relative Value of Diagnostic Imaging

Doppler TTE is the primary method of choice in preoperative diagnostics, including in cases of pulmonary atresia with and without VSD (▶Table 4.17). In order to assess aortopulmonary collaterals, additional imaging is often necessary. Imaging procedures can be performed in vasively if interventional measures or additional parameters that can only be acquired via invasive procedures are scheduled, or by means of contrast-enhanced MRA and CTA. If appropriate protocols are used, radiation exposure from CTA can be lower than that from an invasive cardiac catheter examination. The significance of noninvasive cross-sectional imaging becomes most apparent in postoperative follow-up examinations. In this regard, MRI is at the forefront of assessing biventricular volumes, function, muscle mass, and of quantifying residual insufficiency.










































































































Table 4.17 Focus of imaging diagnostics with the value of individual procedures in cases of pulmonary atresia.

Clinical situation


Common diagnostic tasks


Imaging method of choice


Value of imaging method


Preoperative


Ductal-dependent unifocal pulmonary perfusion


Pulmonary atresia morphology (infundibular, membranous), central pulmonary arteries, ventricular size


Echocardiography


+++


MRI


++


CT


++


Angiography/intervention


++


Multifocal pulmonary perfusion


Aortopulmonary collateral topography, ventricular size


Echocardiography


+++


MRI


++


CT


++


Angiography/intervention


++


Pulmonary atresia in cases of intact ventricular septum


Ventricular size, coronary fistula


Echocardiography


+++


MRI


++


CT


++


Angiography/intervention


++


Postoperative


Increased right ventricular pressure


Pulmonary arterial stenoses, residual MAPCA


Echocardiography


++


MRI


+++


CT


++


Angiography/intervention


++


Relevant conduit stenosis


Right ventricular hypertrophy


Echocardiography


++


MRI


+++


CT


++


Angiography/intervention


++


Relevant insufficiency


Right ventricular size and function, pulmonary valve insufficiency, tricuspid valve insufficiency


Echocardiography


++


MRI


+++


CT


+


Angiography/intervention


++


CT, computed tomography; MAPCA, major aortopulmonary collateral arteries; MRI, magnetic resonance imaging.



4.2.4 Absent Pulmonary Valve

Samir Sarikouch, Matthias Grothoff, Erich Sorantin

Definition

Absent pulmonary valve, a rare congenital disorder, nearly always occurs exclusively in conjunction with tetralogy of Fallot. Only the rudiments of a pulmonary valve have formed, resulting in pronounced pulmonary valve insufficiency (which is even detectable in utero) leading to sometimes massively oversized central pulmonary arteries (▶Fig. 4.49). Chromosomal anomalies, such as microdeletion 22q11 or DiGeorge syndrome, can be detected in some patients. 29

Fig. 4.48 Secondary pulmonary valve replacement using a decellularized homograft (arrow) in a case of pulmonary atresia. The anastomosis on the ventricular side is not yet complete. With the gracious permission of Dr. Thomas Breymann, Medical School of Hannover.)


Natural Progression and Clinical Issues

An impression of the trachea or bronchus, generally combined with malacia of the bronchial tree, often occurs as a result of this massive enlargement of the central pulmonary arterial segments. Severe obstructive crises can result, requiring continued artificial ventilation. 30 If no serious impairment of the airways is present, heart failure due to pulmonary flooding generally occurs within the first 6 months of life.



Treatment Options and Preinterventional Diagnostics

Impressions of the airways with a persistent need for artificial respiration necessitate surgical treatment in newborns. These treatments not only reduce volume load in the pulmonary arteries by closing the VSD, but also allow the pulmonary valve to be replaced. Surgical reduction of the expanded pulmonary arteries often occurs in conjunction with suspensionplasty in order to decompress the airways.


In cases of mild respiratory involvement, surgical correction is performed within the first 6 months of life, similar to tetralogy of Fallot. Doppler echocardiography, alone, is generally sufficient for determining the diagnosis. In order to assess the impression of the airways, another, more in-depth cross-sectional imaging diagnostic method is used—primarily MDCT with the option for multiplanar reformatting.



Postoperative and Postinterventional Issues

Malacia of the trachea and central bronchi generally persists after surgery and improves at varying rates. Despite surgical reduction of the pulmonary arteries, intraluminal treatment may be required. The airways often remain the focus of postoperative imaging diagnostics. Over time, volume overload in the right chamber after surgical correction without replacement of the pulmonary valve can necessitate a secondary replacement. In cases of primary pulmonary valve replacement, the degeneration of largely biological implants leads to RVOT stenosis, which will later require valve replacement surgical or interventional procedures (▶Fig. 4.44).

Fig. 4.49 Absent pulmonary valve. 3-D MIP reconstruction of a contrast-enhanced MRA of the pulmonary arteries in an 18-year-old female patient with an absent pulmonary valve. Continual dilatation of the peripheral pulmonary arterial branches, to a maximum of 48.3 mm near the right pulmonary artery, after a corrective surgery in childhood and a secondary pulmonary valve replacement using a decellularized homograft.


Goals and Relative Value of Diagnostic Imaging

In addition to primary diagnosis, which can generally be performed via echocardiography, assessing pulmonary arterial size (▶Fig. 4.49) and their relationship to the trachea and bronchus are the focus of preoperative diagnostics. In addition to MRI, MDCT with the option for multiplanar reformatting can also be used (▶Table 4.18). In addition to the graduation of residual pulmonary valve insufficiency, right ventricular function, and muscle mass and restenosis near the valve-carrying conduit, assessing the respiratory tract and its anatomical relationship to the pulmonary arteries remains an important component of postoperative follow-up care. MRI can be used to this end, with excellent results.




























































































Table 4.18 Focus of imaging diagnostics with the value of individual procedures in cases of absent pulmonary valve.

Clinical situation


Common diagnostic tasks


Imaging method of choice


Value of imaging method


Preoperative


Need for artificial respiration


Extent and topography of airway compression in relation to the pulmonary arteries


Echocardiography


++


MRI


++


CT


+++


Angiography


+


Heart failure


Right and left ventricular size and function


Echocardiography


++


MRI


+++


CT


+


Angiography



Postoperative


Bronchomalacia


Persistent impression through the pulmonary arteries


Echocardiography


+


MRI


++


CT


+++


Angiography/intervention


+


Neopulmonary valve stenosis


Right ventricular hypertrophy


Echocardiography


+++


MRI


++


CT


+


Angiography/intervention


+


Relevant pulmonary valve insufficiency


Right ventricular size and function, tricuspid valve insufficiency


Echocardiography


++


MRI


+++


CT


+


Angiography/intervention


+


CT, computed tomography; MRI, magnetic resonance imaging.



4.2.5 Ebstein’s Anomaly

Nicole Nagdyman, Matthias Gutberlet

Definition

Ebstein’s anomaly, named after Dr. Wilhelm Ebstein, is an extremely rare congenital heart defect (comprising approximately 0.5% of all congenital heart defects) 31 , 32 in which the septal and possibly also posterior tricuspid leaflets are displaced apically into the right ventricle (▶Fig. 4.50). This leads to division of the right ventricle in- to a basal “atrialized” (non-functional) right ventricle that enlarges the right atrium, and a smaller apical (but functional) right ventricle.

Fig. 4.50 Ebsteins anomaly in varying degrees of severity. Schematic depiction. aRV = atrialized right ventricle (atrialized, non-functional right ventricle) ATL = anterior tricuspid leaflet fRV = functional right ventricle (functional, smaller right ventricle) LA = left atrium; PA = pulmonary artery PTL = posterior tricuspid leaflet RA = right atrium a Mild form. Minor displacement of the posterior tricuspid leaflet and lengthening of the anterior tricuspid leaflet with the correspondingly atrialized right ventricle (cross-hatched surface, indicated with an asterisk). b Severe form with concurrent ASD (arrow). Pronounced adhesion of the posterior tricuspid leaflet and subsequent severe diminishment of the functional segment of the right ventricle.

Individual tricuspid leaflets are dysplastic and may possess narrow attachments, with varying degrees of distinctiveness, to the ventricular septum or right ventricular wall. The anterior leaflet is usually elongated (▶Fig. 4.51; also ▶Fig. 4.50b), but generally originates near the atrioventricular sulcus. Both genetic predisposition and the concurrent myocardial fibrosis have been described in detail. 33

Fig. 4.51 Ebsteins anomaly. The arrows indicate the anterior and septal tricuspid leaflet, respectively. aRV = atrialized right ventricle (atrialized, non-functional right ventricle) ATL = anterior tricuspid leaflet fRV = functional right ventricle (functional, smaller right ventricle) LA = left atrium LV = left ventricle RA = right atrium STL = septal tricuspid leaflet a MRI of an adult male patient with no surgical treatment, SSFP cine sequence, 4-chamber view. Significant apical displacement of the septal tricuspid leaflet (distance indicated in square brackets) with pronounced diastolic bulging (double asterisk) in the left ventricle. Though the anterior tricuspid leaflet attaches to the anatomical annulus fibrosus, it is significantly extended and possesses endocardial adhesions near the free wall of the massively enlarged right ventricle. b Severe case of Ebstein’s anomaly, planimetric image. The atrialized portions are light blue and only the very small, functional portion of the right ventricle is depicted in purple.


Natural Progression and Clinical Issues

Ebstein’s anomaly spans a broad clinical spectrum and ranges from cases diagnosed prenatally (with death in utero) 34 to initial manifestations occurring in 80-year-old patients. 35 Ebstein’s anomaly occurs predominantly in cases of situs solitus, but also with ccTGA in rare cases. In these instances, the anterior leaflet is often smaller and possesses an additional cleft in 30% of cases.


The hemodynamic effects of Ebstein’s anomaly are determined by the size and pumping capacity of the right ventricle, as well as the concurrent valve malfunction, namely tricuspid valve insufficiency. It can, however, also lead to functional stenosis or even atresia. An ASD (▶Fig. 4.50b) or PFO (▶Fig. 4.50a) occurs in about 80% of patients. 36 In cases of pronounced tricuspid valve insufficiency or limited right ventricular function, a right–left shunt with cyanosis can occur via the defect (▶Fig. 4.50b).


Accessory conduction tracts are generally localized around the opening of the malformed valve 37 (e.g., within the scope of Wolff–Parkinson–White syndrome) and are visible in about 20% of patients with Ebstein’s anomaly.


Right ventricular dilatation can lead to impairment of the interventricular septum and, subsequently, diastolic disruption of left ventricular filling with a subsequent reduction in left-side pumping capacity. This is depicted in dynamic images as diastolic bulging (▶Fig. 4.51, ▶Fig. 4.52, ▶Fig. 4.53, ▶Fig. 4.54e, and ▶Fig. 4.51d).

Fig. 4.52 Severe case of Ebsteins anomaly. The triple asterisk indicates the position of a pacemaker lead in the right ventricle. aRV = atrialized right ventricle (atrialized, non-functional right ventricle) fRV = functional right ventricle LA = left atrium LV = left ventricle RA = right atrium a 2-D TTE during diastole, apical 4-chamber view, in a 59-year-old male patient with Ebstein’s anomaly and an implanted pacemaker, with no previous surgical correction. Significant apical displacement of the septal tricuspid leaflet (square brackets) with diastolic bulging (a, b, double asterisk) of the interventricular septum into the left ventricle. Large atrialized right ventricle and relatively small, functional right ventricle. b Using color Doppler during systole, the 2-D TTE of the same patient shows a pronounced tricuspid valve insufficiency jet (blue) in the atrialized segment of the right ventricle and into the right atrium. c No septal bulging is visible during systole.
Fig. 4.53 Severe case of Ebsteins anomaly. Forty-two-year-old female with Ebstein’s anomaly and no prior surgical treatment. Left ventricle, displaced left dorsally by the atrialized right ventricle during diastole (a, arrows). Evidence of diastolic bulging (b, d, double asterisk) and sectional plane (d, dotted line) for the short-axis slice in c. The atrialized right ventricular segment and its relation to the functional right ventricle and RVOT is marked schematically (light blue area) in the mid-ventricular short-axis slice (c). The square brackets in b and d indicate the apical displacement of the septal tricuspid leaflet. AAo = ascending aorta aRV = atrialized right ventricle (atrialized, non-functional right ventricle) fRV = functional right ventricle (functional, smaller right ventricle) LA = left atrium LV = left ventricle RA = right atrium RVOT = right ventricular outflow tract a Levocardiogram of an invasive cardiac catheter examination during diastole, RAO projection. b Transverse MRI SE image. c SSFP cine MRI sequence, mid-ventricular short axis. d SSFP cine MRI sequence during diastole, 4-chamber view.
Fig. 4.54 Ebsteins anomaly with concurrent ASD. Fifty-nine-year-old female patient with no previous surgical treatment, with Ebstein’s anomaly and an ASD that was closed using an atrial occlusion device (a, b, blue circle). Multiplanar reformats of a MDCT data set are visible in c–f. The triple asterisk (e, f) indicates the occlusion device. In addition, artifacts of the pacemaker lead in the right ventricle are visible in each reformat (c–f, asterisk). The atrialized portion (light blue area) and functional segment of the right ventricle (pale red area) are marked schematically in all orientations (c–e). aRV = atrialized right ventricle (atrialized, non-functional right ventricle) fRV = functional right ventricle (functional, smaller right ventricle) LA = left atrium LV = left ventricle RA = right atrium a P.-a. X-ray. Typical “Bocksbeutel” (Franconian wine bottle) shape of the heart caused by enlargement of the right atrium and ventricle. b Lateral X-ray. Enlarged depiction of the atrial septal occlusion device. c Coronal reformat from an MDCT data set. d Sagittal reformat from an MDCT data set. e Transverse reformat from an MDCT data set marking the atrialized, non-functional right ventricle and the functional, smaller right ventricle. f Transverse reformat from an MDCT data set during diastole, without marking. Significant bulging of the interventricular septum into the left ventricle is visible.

Under certain circumstances, severe forms of Ebstein’s anomaly can be associated with mortality in newborns. 38 Due to the postnatal increase in pulmonary vascular resistance, not much blood flows through the circulatory system, tricuspid valve insufficiency is exacerbated, and patients present with pronounced cyanosis, right heart failure, and limited systemic cardiac output. Tricuspid valve insufficiency causes progressive heart failure that can be associated with hepatomegaly, edema formation, and metabolic acidosis.


Mild forms are often discovered by accident. Moderate forms show the start of limited exercise capacity during adolescence or adulthood, or in cases of concurrent ASD, cyanosis while at rest or when subjected to stress.


Various classification systems, such as Carpentier’s surgical classification 39 or newborn echocardiographical classification, 38 were developed in order to adapt treatment strategies based on the illness’s severity.



Treatment Options and Preinterventional Diagnostics

Patients with mild forms of Ebstein’s anomaly often need no treatment for years or even decades, while patients with moderate forms benefit from medication treatment for heart failure once they begin to display signs of limited exercise capacity.


Critically ill newborns with severe forms of Ebstein’s anomaly may, under certain circumstances, require prostaglandin E in order to improve pulmonary circulation via the ductus arteriosus and, if needed, supplementary mechanical respiration or catecholamine therapy. It may be necessary to perform a palliative surgery with a final option to separate circulation by a FONTAN operation. 40


Generally accepted indications for surgery:




  • Limited exercise capacity corresponding to NYHA class III



  • Pronounced cyanosis



  • Development of paradoxic embolisms



  • Cardiothoracic ratio of more than 0.65 in X-rays


Various tricuspid valve reconstruction procedures that include reduction (plication) of the atrialized right ventricle have also been described. 39 , 41 , 42 Sebening et al. developed a technique that encompassed forming a monocuspid valve while retaining the atrialized ventricular segment 43 —similar to the surgical method developed by Hetzer et al. 44 —in which the atrialized ventricular segment also remains untouched. It is intended to reduce the anatomical tricuspid valve opening, so that the most mobile leaflet (usually the elongated anterior leaflet) finds a contralateral structure for systolic valve closure. In severe cases, a bidirectional shunt or Fontan tunnel can be placed in order to reduce right ventricular overload. 40 The cone technique established by Da Silva et al. is growing more popular. 45 This technique involves removing the anterior leaflet and then mobilizing the septal and posterior portions and plicating the right ventricle in order to construct a new valve apparatus composed entirely of the body’s own leaflet tissue.


Patients with symptomatic Wolff–Parkinson–White syndrome should receive an electrophysiological examination with ablation of the accessory tracts. In these cases, however, the success rate is lower, and the risk of recurrence in patients with Ebstein’s anomaly is higher than in patients with structurally unremarkable hearts.


Patients with intermittent or chronic atrial flutter may also benefit from a maze procedure within the scope of valvular surgery. The goal of this surgery, just like interventional ablation, is to interrupt repeated events; switch off spontaneously active, rapidly “firing,” stimulation-causing centers; and to reinstate normal pathways and coordinated activation of the atrial muscle tissue.



Note

Since progressive heart failure is a significant risk factor for postoperative fatality, nowadays it seems more beneficial to document and operate on patients during NYHA stage II, before a significant drop in cardiac performance.



Postoperative Issues

In the phase immediately after surgery, right ventricular function may initially be so severely limited that catecholamine treatment is unavoidable.


One Mayo Clinic study with a large patient population described right ventricular functional disorders, primarily cardiac rhythm disorders, which resulted in a large rehospitalization rate over the long term. 46 Reoperations for the tricuspid valve are relatively common, both after reconstruction and after successful valve replacement. It remains to be seen whether the cone technique will improve this application.



Goals and Relative Value of Diagnostic Imaging

Echocardiography is the simplest and most widely used procedure (▶Table 4.19) for diagnosing Ebstein’s anomaly (▶Fig. 4.52). Diagnosis often occurs prenatally via fetal echocardiography. The 4-chamber view in 2-D echocardiography makes it possible to assess the apical displacement of the tricuspid leaflet, its adherence to the wall, and the size of the right ventricle. Special indices allow examiners to assess the extent of the anomaly. 47 Furthermore, an ASD or PFO can be visualized. Color Doppler sonography allows the insufficiency to be depicted, while simple Doppler sonography allows the tricuspid valve stenosis to be visualized (▶Fig. 4.52b). Shunts (and their orientation) in the atrial region can also be depicted clearly.






























































































































Table 4.19 Value of individual diagnostic procedures in assessing various aspects of Ebstein’s anomaly.

Findings


Echocardiography


P.-a. + thoracic X-ray, lateral


MRI with flow measurement


MDCT, ECG-triggered


Cardiac catheter


TTE


TEE


3-D


Morphology of the tricuspid valve apparatus


Dysplasia and dislocation


high


high


high



high


moderate


moderate


Wall adherences


high


high


high



high


high


moderate


Tricuspid valve function


Insufficiency


high


high


moderate



high


moderate


moderate


Stenosis


high


high




high


moderate


high


Size of cardiac compartments


Right atrium


high


high


high


moderate


high


high


moderate


Right ventricle (including atrialized ventricle)


moderate


high


moderate to high


moderate


high


high


moderate


Left ventricle (including paradoxical septal motion)


high


high


high


moderate


high


high


high


Left atrium


high


high


high


moderate


high


high


moderate


Function of cardiac compartments


Right ventricle


moderate


high


high



high


moderate


high


Left ventricle


high


high


high



high


moderate


high


CT, computed tomography; MRI, magnetic resonance imaging; TEE, transesophageal echocardiography; TTE, transthoracic echocardiography.


3-D ECG can be used to visualize the precise morphology of the tricuspid leaflet or to conduct functional analyses. 48 , 49


TEE is used primarily before and after heart surgery. This method emphasizes visualizing the surgically usable leaflet, namely its size, mobility, attachments, and fenestrations. Cardiac and tricuspid valve function (residual insufficiency, ruling out stenosis) are assessed using TEE both during and after surgery.


An invasive cardiac catheter examination (▶Fig. 4.53a) should not be performed until there is suspicion of additional anomalies that cannot be explained via echocardiography or MRI, and is helpful as an electrophysiological examination in the presence of symptomatic accessory pathways.



Note

In cases of cyanosis while at rest or under stress in mild cases of tricuspid valve insufficiency, interventional closure of the ASD (▶Fig. 4.54) should be discussed. During the intervention, however, it must be ensured that the closure will not in any way impair ventricular function.


The X-ray examination depicts the characteristic, Franconian wine bottle shape of the heart’s silhouette (▶Fig. 4.54a and b), which develops primarily as a result of right atrial dilatation. A cardiothoracic ratio of more than 0.65 is associated with worse prognoses. 50


In recent years, MRI has gained a great deal of traction as a noninvasive procedure in preoperative diagnostics (▶Table 4.19). 51 , 52 In cases of very complex 3-D anatomy, MRI yields accurate information regarding the size and function of the atrialized and functional segments of the right ventricle, as well as extremely helpful information on the morphology of the displaced tricuspid leaflets (▶Fig. 4.51 and ▶Fig. 4.53). As a result, MRI has become a crucial information source for surgical planning. In addition, it is possible to perform absolute quantification of tricuspid valve insufficiency and shunt volume in cases of concurrent ASD or PFO, using a combination of volumetric analysis of the right atrium and ventricle, and MRI flow measurement using the phase contrast technique. 53 55 Planning the cine MRI sequence in transverse slices is especially helpful for precise planimetric analysis of the atrialized and functional segments of the right ventricle (▶Fig. 4.51).


CT is used only rarely in patients with Ebstein’s anomaly, both due to radiation exposure and to the generally good image quality yielded by echocardiography and MRI examinations. 56 In patients that are difficult to image and for whom MRI examinations are contraindicated (such as those with cardiac pacemakers), CT remains a viable alternative (▶Fig. 4.54). Volumetric and functional analysis of the right ventricle can also be performed in conjunction with MDCT, though this results in worse temporal resolution.



4.3 Left-Side Defects



4.3.1 Subaortic Stenosis, Valvular Aortic Stenosis, and Supravalvular Aortic Stenosis

Joachim Lotz, Joachim G. Eichhorn, Michael Steinmetz

Definition

Stenoses near the LVOT can take the form of subvalvular, valvular, or supravalvular aortic stenoses (▶Fig. 4.55). Aortic coarctation is a special form of aortic stenosis. These stenoses are similar, in that they lead to increased afterload in the left ventricle. They can occur in isolation or in conjunction with other defects.

Fig. 4.55 Various forms of aortic stenoses. Schematic depiction. AAo = ascending aorta AoV = aortic valve LA = left atrium LV = left ventricle. a Subvalvular stenosis with subvalvular membrane (asterisk) and subvalvular muscular bulge (double asterisk) in the LVOT. b Valvular aortic stenosis (asterisk) with thickened semilunar valve. c Supravalvular aortic stenosis with supravalvular membrane (asterisk).


Classification


Subvalvular Aortic Stenosis

In cases of isolated subvalvular aortic stenosis, a fibrous membrane or fibromuscular ring is generally located below the aortic valve (▶Fig. 4.56; also ▶Fig. 4.55a). In rare cases, muscular bulging occurs in isolation near the septum, accessory mitral valve tissue, or a malformed mitral valve apparatus as a result of subaortic stenosis. In cases of HOCM, muscular subaortic stenoses can also occur due to asymmetrical septal hypertrophy with potential obstruction near the LVOT.

Fig. 4.56 Subvalvular aortic stenosis. Two different patients. AAo = ascending aorta AoV = aortic valve LA = left atrium LV = left ventricle MV = mitral valve PA = pulmonary artery RA = right atrium RV = right ventricle TV = tricuspid valve a 2-D TTE image, parasternal long axis, of a patient with subvalvular aortic stenosis (asterisk), clearly depicting the bilateral subvalvular membrane in the LVOT, inferior to the opening aortic valve. b SSFP cine MRI, coronary section, of another patient with subvalvular aortic stenosis (asterisk), depicting both the subvalvular membrane and dephasing jet during systole, rendered visible by flow acceleration in the LVOT.

Shone’s complex, defined as a combination of subaortic stenosis with an abnormal mitral valve and an aortic coarctation, should be regarded as a special form of subaortic stenosis.


Subvalvular aortic stenoses are often components of complex cardiac abnormalities (DORV, malalignment VSD, etc.). Thirty-seven percent of patients with an isolated subvalvular aortic stenosis also possess a perimembranous VSD. Corrective surgeries (e.g., in cases of VSD, AVSD, complex defects) can also cause a secondary subaortic stenosis to form.



Aortic Valve Stenosis

In aortic valve stenosis (▶Fig. 4.55b) the aortic valve generally opens incompletely due to congenital or acquired thickening or merging of individual cusps. An undersized valve ring is another potential cause. Congenital or functional bicuspid valves that do not open fully due to merging of the commissures (raphe formation) remain the most common cause (▶Fig. 4.57 and ▶Fig. 4.58).

Fig. 4.57 Isolated, congenitalbicuspidalizedtype 1 N/R aortic valve and moderate stenosis. (▶Fig. 4.58). Twenty-five-year-old male patient. A maximum instantaneous pressure gradient of 30 mmHg was estimated using doppler echocardiography. The patient exhibited no clinical symptoms. LA = left atrium LV = left ventricle LVOT = left ventricular outflow tract PA = pulmonary artery RA = right atrium a Coronal SSFP cine MRI during systole, with a fully opened aortic valve and signal loss caused by dephasing (double asterisk) in a case of turbulent flow due to flow acceleration. The blue line indicates the sectional plane for c–e for depiction and planimetric analysis of the aortic valve. b LVOT image corresponding to a. Here, the blue line also indicates the sectional plane for c–e for the depiction and planimetric analysis of the aortic valve. c Magnitude image of through-plane flow measurement (section in accordance with the blue lines in a and b) of the fully opened bicuspid aortic valve with a maximum valve opening area of 1.4 cm2(d). The three sinuses and the raphe (asterisk) between the right coronary and non-coronary cusp are visible in c and d. d The maximum valve opening area in systole is depicted as the red area in planimetric measurements. This can, in principle, also be performed in the phase image (e). e Phase image corresponding to c. Cranial flow is depicted in black. The maximum measured flow velocity in MRI was 3.1 m/s in the sense of an estimated maximum instantaneous pressure gradient of 38 mmHg.
Fig. 4.58 Classification of bicuspid andbicuspidalizedaortic valves. Schematic depiction of classification (top) 57 with the corresponding intraoperative examples and pathologies (bottom). Note: In cases of true bicuspid aortic valve, both valves are usually the same size and only two sinuses exist. In cases of “bicuspidalized” aortic valve, the semilunar valves are merged via one or two raphes (black) and possess three sinuses. (Intraoperative images with the gracious permission of Dr. E. Girdauskas, Cardiac Surgery Clinic, Bad Berka Central Hospital.) L = left coronary cusp LCA = left coronary artery N = non-coronary cusp R = right coronary cusp RCA = right coronary artery

A distinction is made between the following forms (▶Fig. 4.58):




  • true bicuspid valve with only two sinuses, and generally two semilunar valves of the same size, and



  • the much more common “bicuspidalized” aortic valve which, from an anatomical perspective, possesses three sinuses and three semilunar valves, two of which are merged via a thickening (known as a raphe), meaning that these valves are generally of two different sizes.


Pathological and anatomical specimens also show a rudimentary third cusp, even when imaging apparently bicuspid valves.


Bicuspid aortic valve often occurs in conjunction with an aortic coarctation. Monocuspid valves can also occur. The cusps may also thicken in cases of congenital or acquired valve dysplasia (e.g., after rheumatic fever). This can also lead to valves being unable to open fully. In extreme cases, the valve cannot be defined, and appears perforated. The degree of severity of aortic stenosis is classified in accordance with ▶Table 4.20.


















































Table 4.20 Classification of the degree of severity of aortic valve stenosis. Classification based on pressure gradients can also be applied to subvalvular and supravalvular aortic stenoses. 61

Degree of severity


Cardiac catheter peak gradient


(mmHg)


CW Doppler v max


(m/s)


Bernoulli maximum instantaneous gradient


(mmHg)


Bernoulli mean instantaneous gradient


(mmHg)


Echo aortic valve orifice area


(cm2)


Trivial

         

Minor


< 30


< 3


< 36


< 25


> 1.5


(> 1 cm2/m2)


Moderate


30–50


3–4


36–64


25–40


1.0–1.5


(0.6–1.0 cm2/m2)


Severe


> 50


> 4


> 64


> 40


< 1.0


(< 0.6 cm2/m2)


CW, continuous wave.



Note

Aortic coarctation is often concurrent with a bicuspid aortic valve.


Critical aortic stenosis in newborns is its own independent entity. In these cases, systemic circulation perfusion remains dependent on the arterial duct, even postnatally. If untreated, critical aortic stenosis can lead to acute heart failure and left ventricular decompensation postnatally. Prenatally, it can lead to the development of endocardial fibroelastosis or hypoplastic left heart syndrome (HLHS).



Supravalvular Aortic Stenosis

Supravalvular aortic stenosis (▶Fig. 4.59 and ▶Fig. 4.60; also ▶Fig. 4.55c) can occur in isolation or in conjunction with other defects. Most commonly, hourglass-shaped stenoses are found near the sinotubular junction, while more extensive stenoses, hypoplasia of the aorta as a whole, or membranous forms occur in rarer cases.

Fig. 4.59 Supravalvular aortic stenosis. Two patients. Two-month-old infant with hypoplastic aortic arches, condition after surgical reconstruction of the aortic arch (a, b). Residual stenosis near the ascending aorta (a, arrow). A 2-D TTE image, parasternal long axis, of another patient with supravalvular aortic stenosis (c, d) clearly shows the supravalvular membrane (arrows) and flow acceleration in color Doppler. AAo = ascending aorta AoV = aortic valve a 3-D reconstruction of a contrast-enhanced MRA for a supravalvular aortic stenosis, angulated sagittal orientation, along the aortic arch. b Through-plane acquisition of a phase contrast image, depicting slightly increased cranial flow in white. The maximum measured flow velocity was 2.5 m/s, corresponding to an estimated maximum instantaneous pressure gradient of 25 mmHg. Flow velocity was 1.1 m/s proximal to the stenosis in the ascending aorta. c 2-D TTE depiction of a supravalvular aortic stenosis (arrow), parasternal long axis, without a color Doppler signal. d 2-D TTE of a supravalvular aortic stenosis (arrow), parasternal long axis, with color Doppler signal and corresponding flow acceleration.
Fig. 4.60 Combined valvular and supravalvular aortic stenosis and left and right coronary artery origin stenoses. Seventeen-year-old female patient with a mutation in the elastin gene and dysplastic aortic valve syndrome. The arrows in a and b indicate the supravalvular aortic stenosis, and the asterisk in a indicates the origin stenoses in the left coronary artery. LV = left ventricle a Cardiac catheter examination with angiography of the ascending aorta, LAO projection. The peak pressure gradient, measured invasively, corresponded to 100 mmHg. b Cardiac catheter examination with angiography of the ascending aorta, RAO projection. c Corresponding 2-D TTE image, 5-chamber view, depicting a small aortic valve with a diameter of 15 mm (arrow), corresponding to less than two standard deviations from the standard based on body surface area. d Significant flow acceleration to a maximum of 5.8 m/s in CW-Doppler, with an estimated mean pressure gradient of 80 mmHg and a maximum of 134 mmHg. e Color Doppler depiction (arrow) of the concurrent aortic valve insufficiency.

A histological examination nearly always reveals a change in media formation or collagen or elastic fibers, meaning that the aortic wall is less elastic and Windkessel function is limited. The distal segments of the commissures are affected, which may result in limited mobility. This can lead to coronary displacement or stenoses caused by atypical cusps. In certain cases, stenoses may also occur in the vessels originating from the aorta. A combination of subvalvular and supravalvular aortic stenoses is common. Various syndromes are associated with supravalvular aortic valve stenosis: Perhaps the best known is Williams–Beuren syndrome. Supravalvular aortic stenoses can, however, also occur in cases of genetic aortic disease (elastic gene mutation), in cases of genetic hypercholesterinemia, and other genetic disorders. 58



Hemodynamics

An obstruction of the LVOT, aortic valve, or ascending aorta increases afterload in the left ventricle, leading to consecutive hypertrophy and, as it progresses, to limited contractility. This is directly dependent on the degree of stenosis and the pressure gradients that must be overcome in the left ventricle. In addition, flow acceleration and turbulence of the blood near and distal to the stenosis (▶Fig. 4.61) can occur. These phenomena can be visualized clearly, particularly when using 4-D flow measurement.

Fig. 4.61 Tricuspid and bicuspidalized aortic valve. 4-D MR flow measurement in an animal model. a Normal tricuspid aortic valve. b Bicuspidalized aortic valve. In addition to flow acceleration, turbulence is occurring near the ascending aorta.


Clinical Issues

Cases of isolated subvalvular or supravalvular aortic stenosis often do not present clinical symptoms for a long time. More severe stenoses can be associated with limited exercise capacity up to manifest heart failure with pulmonary edema. In rare cases, syncope or the symptoms of angina pectoris may occur. From an auscultory viewpoint, a harsh crescendo systolic murmur can be heard with a maximum point above the second-left intercostal space and radiating into the carotid arteries.



Natural Progression and Indication for Treatment

Pronounced subvalvular and supravalvular aortic stenoses are generally progressive. Less pronounced forms can, however, remain unchanged for many years. 59 They usually are not present at birth, but rather develop during the first few years of life. In rare cases, fetal or neonatal subaortic stenoses occur in conjunction with endocardial fibroelastosis and a hypoplastic left ventricle. Aortic valve insufficiency can also occur in conjunction with the initial stenoses, primarily in cases of progressive ectasia of the ascending aorta.


Indication for treatment is determined based on the guidelines of the Germany Association for Pediatric Cardiology 60 , 61 for cases of isolated subvalvular, valvular, or supravalvular aortic stenoses with a median Doppler gradient > 40 mmHg, a valve opening area < 1 cm2, or a peak-to-peak pressure gradient (measured invasively) > 50 mmHg (▶Table 4.20). Independent of gradients, treatment is indicated under the following conditions:




  • development of complaints (i.e., heart failure, angina pectoris)



  • progressive left ventricular dilation or reduced left ventricular function



  • new or progressive aortic valve insufficiency



  • ECG repolarization disorders


In cases of combined subaortic stenosis associated with other cardiac abnormalities, the overall findings are decisive when making treatment decisions. 60 , 61



Treatment Options and Diagnostics

In addition to echocardiography, cardiac MRI, or cardiac CT, diagnostic procedures—especially in cases of complex defects—include invasive cardiac catheter examinations (▶Fig. 4.60). Morphology and valvular or ventricular function remain the focus 62 of these procedures. For noninvasive procedures, doppler echocardiography and MRI best address both topics. Both modalities can provide either planimetric estimates or indirect estimates of maximum instantaneous pressure gradients via the stenosis, with the help of flow measurement and the Bernoulli equation. If precise invasive pressure gradient measurement is needed, or if it is necessary to depict the coronaries or even to perform simultaneous treatment, then invasive cardiac catheter examinations are the method of choice (▶Fig. 4.60).


In cases of subvalvular aortic stenosis, treatment consists of surgically resecting the fibrous ring, with or without myectomy. In rare cases, patch reconstruction of the LVOT (also known as the Konno procedure) is necessary in cases in which tunnel-shaped stenoses are present. 63 The risk of recurrence in cases of simple resection is 20% within 10 years. 64 Purely interventional treatment using balloon valvuloplasty has achieved good results thus far in cases of subvalvular aortic stenosis. 65


Valvular and sometimes also supravalvular aortic stenoses, on the other hand, can often be treated using purely interventional procedures, such as balloon valvuloplasty. 66 In cases of valvular aortic stenoses, however, there is a risk of aortic valve insufficiency developing as a result of the intervention, itself. Traditional surgical treatment consists of aortic valve replacement. In these cases, both mechanical aortic valves (requiring lifelong anticoagulation treatment) and biological aortic valves (with limited durability) can be used. Biological valves present the choice between xenografts (e.g., valves from a pig), homografts (human aortic grafts), and autografts, in which the patient’s own pulmonary valve is implanted in the aorta’s place and the pulmonary valve is then replaced using a homograft or a conduit with a mechanical valve, also known as the Ross procedure. 67 In addition, the option for valve reconstruction may exist if certain prerequisites are met. 68



Postoperative and Postinterventional Issues

Possible complications after surgical treatment of an aortic stenosis include the following:




  • aortic valve insufficiency



  • damage to the mitral valve, particularly to the anterior mitral leaflet, requiring mitral valve reconstruction or even replacement



  • iatrogenic VSD



  • cardiac rhythm disorders



  • the development of left bundle branch block or atrioventricular block


During surgical treatment of the supravalvular aortic stenosis, coronary perfusion disorders may arise based on the need for coronary reimplantation. Stenosis of the valve-equipped conduit or of the homograft from the right ventricle to the pulmonary artery can result from a Ross procedure. This may be difficult to see with TTE, particularly in older patients, due to the retrosternal positioning. In these cases, MDCT and MRI offer the additional option of graduating the stenosis, e.g., via MR flow measurement as a good alternative to Doppler echocardiography. 7



Goals and Relative Value of Diagnostic Imaging

The general goal of preinterventional and postinterventional imaging is assessing the degree of severity of the stenosis and acquiring as precise a description as possible of its morphology in order to classify the stenosis more accurately. 57 In addition, imaging is intended to assist with the description of close anatomical relationships with the mitral valve apparatus and with any other potentially associated defects, as well as with the assessment of hemodynamic effects (e.g., regarding left ventricular function and muscle mass). 7 , 69 Particularly in cases of valvular stenoses, valve morphology must be visualized precisely in order to be able to evaluate the possibility of valve reconstruction compared to valve replacement.



Note

Before a Ross procedure or replacement of the ascending aorta, the diameter of the aortic annulus, LVOT, ascending aorta (and pulmonary valve annulus for Ross procedures), RVOT, and main pulmonary artery should be determined for surgical planning purposes.


Within the scope of standard diagnostics, the position, morphology, and degree of severity of the stenosis can be evaluated using TTE, or TEE under poor imaging conditions. The dimensions of the LVOT and the aortic valve, as well as the involvement of the mitral valve or mitral valve apparatus in the stenosis, can generally be assessed clearly. Both left ventricular size and hypertrophy, as well as concurrent aortic valve insufficiency can also be clearly assessed (▶Fig. 4.56a, ▶Fig. 4.59c, d and ▶Fig. 4.60c).


In addition, it is also possible to assess the pulmonary valve, RVOT, and pulmonary vascular bed in light of a Ross procedure. Doppler echocardiography allows us to estimate the maximum and mean gradients. Associated cardiac defects can also be described or ruled out, and the degree of aortic valve insufficiency can be assessed. The majority of patients, particularly young patients who can be imaged easily, can undergo surgery only after doppler TTE diagnostics have been performed. 59 62


Particularly in cases of associated defects in which additional information is necessary (e.g., regarding the course of the coronaries for planned myectomies or septostomy, aortic valve replacement, Ross procedures, or ascending aorta replacement), as well as for postoperative patients, 7 , 13 , 69 cross-sectional imaging procedures such as MRI or MDCT can be used.



Note

In general, MRI and multi-slice CT are only class I3 indications, 7 meaning that their use is technically possible and validated, but is only indicated on a case-by-case basis.


A cardiac catheter examination may be necessary in order to determine pressure gradients via the stenosis with precision, or in cases of complex defects. Post-stenotic dilatation of the ascending aorta can be visualized and quantified using a cardiac catheter, MRI, or multislice CT (▶Table 4.21).
































































































































Table 4.21 Relative value of individual imaging procedures for assessing various aspects of aortic stenoses. 7 , 61

Findings


Echocardiography


Thoracic X-ray, a.-p./lateral


MRI with flow measurement


MDCT, ECG-triggered


Cardiac catheter (angiography and hemodynamics)


TTE


TEE


3-D


Morphology of the valve apparatus and stenosis


Bicuspid/tricuspid


moderate


high


high



high


high


moderate


Wall adherences


high


high


high



high


moderate


moderate


Aortic valve function


Insufficiency


high


high




high


low


high


Stenosis


high


high




high


moderate


moderate


Graduation of stenosis


Morphological


high


high


high



high


high


moderate


Functional


high


high


high



high


low


high


Left ventricular function and myocardial morphology


Left ventricular function


high


high


high



high


moderate


high


Myocardial morphology


high


high




high


high


moderate


Left ventricular size


high


high


high


moderate


high


high


high


Morphology of the ascending aorta


Post-stenotic dilatation


moderate


low



moderate


high


high


high


a.-p., anterior–posterior; ECG, electrocardiography; MDCT, multidetector computed tomography; MRI, magnetic resonance imaging; TEE, transesophageal echocardiography; TTE, transthoracic echocardiography.



4.3.2 Aortic Coarctation

Joachim Lotz, Joachim G. Eichhorn, Michael Steinmetz

Definition

Aortic coarctation is defined as more than 25–30% narrowing of the diameter of the aorta at the transition between the origin of the left subclavian artery and the distal aortic arch in the descending aorta (generally originating from the posterior wall opposite the duct opening), which is exacerbated by membrane-like thickening of the intima media (▶Fig. 4.62 and ▶Fig. 4.63). It comprises approximately 5–8% of all congenital heart defects, and is twice as common in men as in women.

Fig. 4.62 Aortic coarctation. Moderate aortic isthmus stenosis near the transition between the origin of a typically dilatated left subclavian artery and the distal aortic arch in the descending aorta, through a membrane-like thickening of the intima media on the opposite (juxtaductal) posterior wall (arrow) superior to the ductus arteriosus. AAo = ascending aorta DAo = descending aorta LPA = left pulmonary artery PA = pulmonary artery RPA = right pulmonary artery a Schematic depiction. b Parasagittal MIP reconstruction of a contrast-enhanced MRA.
Fig. 4.63 Aortic coarctation. AAo = ascending aorta Ao = aorta DAo = descending aorta LA = left atrium PA = pulmonary artery. a Schematic depiction of the suprasternal view of an aortic coarctation in an infant, CW Doppler, for evaluating maximum instantaneous pressure gradients. b Typical 2-D echo image, suprasternal long axis, with an angular course of the descending aorta and minor “ridge” pulling medially into the lumen of the descending aorta. c Corresponding color Doppler image with minor flow acceleration near the isthmus.


Classification

The previous classification into preductal and postductal (or infantile and adult) aortic isthmus stenoses, which was once common, is generally no longer used. The stenosis is generally located opposite (or juxtaductal to) the ductus arteriosus (▶Fig. 4.62). One exception is critical aortic coarctation in newborns, which can lead to emergency situations in cases of acute duct closure (see below).


Aortic coarctation is often associated with additional heart defects, most commonly with bicuspid aortic valve (in up to 85% of cases), and generally with aortic valve stenosis, PDA, VSD, and even additional arterial vascular anomalies, such as atypical origins of the right subclavian artery (lusoria artery) or origin stenosis of the left subclavian artery. Aortic coarctation commonly (in approximately 30% of cases) also develops in female patients with Turner syndrome (X0 chromosome).



Hemodynamics

In cases of critical aortic coarctation in newborns, perfusion in the lower half of the body depends on the persistence of the ductus arteriosus, which, as a right–left shunt, directs oxygen-depleted blood from pulmonary circulation into the descending aorta. Correspondingly, cyanosis (arterial oxygen saturation generally corresponding to 75–85%) then develops in the lower half of the body, whereas the upper half of the body (as measured on the right arm) experiences normal arterial oxygen saturation. Closing the PDA can, in acute situations, lead to increased afterload and consecutive left ventricular decompensation accompanied by heart failure and cardiogenic shock.



Note

Even in cases of minor aortic coarctation, increased afterload and consecutive ventricular hypertrophy occurs in the left ventricle. Arterial hypertonia develops in the upper half of the body proximal to the stenosis, and—in cases of normal or decreased arterial blood pressure—in the lower half of the body distal to the stenosis. The resulting blood pressure gradient between the upper and lower extremities is an important diagnostic indication for the presence of an aortic coarctation.


In cases of persistent and hemodynamically relevant aortic coarctation, pronounced collateral circulation between the upper and lower halves of the body often develops. Typical collateral vessels, sometimes with reverse flow, are the internal mammary or internal thoracic arteries, the aortic intercostal arteries of the third–eighth intercostal area, and the left subclavian artery, which then dilate as a result of their increased internal flow (▶Fig. 4.64 and ▶Fig. 4.65). This phenomenon can be visualized clearly using different imaging modalities.

Fig. 4.64 Aortic coarctation with collateralization. Sixteen-year-old male patient with high-grade aortic coarctation (c, d, asterisks) and pronounced collateralization. The left subclavian artery dilated significantly by collateral flow is depicted in the MIP reconstruction (c, d, double asterisk). AAo = ascending aorta Ao = aorta DAo = descending aorta a Thoracic X-ray, p.-a. projection. The enhanced image depicts examples of typical rib notching (double asterisks) on the lower margin of the third–eighth dorsal ribs caused by intercostal collaterals. b Thoracic X-ray, lateral view. c Corresponding 3-D MIP reconstruction of a contrast-enhanced MRA, RAO projection. d Corresponding 3-D MIP reconstruction of a contrast-enhanced MRA, lateral projection.
Fig. 4.65 Possible collateral flows in a case of aortic coarctation. Schematic depiction.


Clinical Issues

After the PDA has been closed, critical aortic coarctation in newborns leads inevitably to acute left ventricular heart failure with the development of tachydyspnea, tachycardia, a blue-gray skin discoloration, renal failure, and intestinal hypoperfusion, with risks ranging from the development of necrotic enterocolitis all the way up to cardiogenic shock.


Patients with non-critical aortic coarctation have a difference in blood pressure between their upper and lower extremities, as well as arterial hypertonia proximal to the stenosis. Based on severity, this leads to symptoms such as weakened femoral pulse and cold feet, the development of an intermittent claudication, headaches, and epistaxis. Furthermore, the chronic increased afterload causes left ventricular hypertrophy, which, depending on its severity, can lead to chronic heart failure.



Natural Progression and Indication for Treatment

After the PDA is closed, critical aortic stenosis in a newborn is incompatible with life. Under these circumstances, there is always an indication for treatment, often on an emergent basis. If treatment cannot be performed immediately, the PDA must be held open using a prostaglandin E1 infusion, and catecholamine treatment should be initiated before the operation.


Depending on form, non-critical aortic coarctation may only cause arterial hypertonia, with the corresponding elevated risk of cardiovascular events. It may remain undiscovered until late into adulthood.


Indication for treatment exists in cases of a systolic blood pressure gradient of 20 mmHg between the upper and lower halves of the body. Treatment is also indicated if a systolic blood pressure gradient of less than 20 mmHg associated with arterial hypertonia (for children over the 97th blood pressure percentile by age) and a morphologically significant narrowing (stenosis or aortic diameter near the diaphragm of less than 0.8 mm) 70 , 71 are present.



Treatment Options and Preinterventional Diagnostics

For newborns and infants, surgical correction by means of a left lateral thoracotomy is the treatment method of choice. We strive to resect the stenosis and establish an end-to-end anastomosis, ideally without using foreign materials (▶Fig. 4.66). Alternatively, a subclavian flap aortoplasty (▶Fig. 4.67) or indirect dilatation using foreign materials (Goretex or Dacron) is performed. Nowadays, this surgical technique, known as a “Vossschulte patch aortoplasty,” has largely been abandoned due to the aneurysms that commonly occur near the patch (▶Fig. 4.68).

Fig. 4.66 Condition after surgical correction of an aortic coarctation by means of end-to-end anastomosis. Only minor residual or restenosis with minor post-stenotic dilatation of the ascending artery is visible. a Parasagittal subtractive reconstruction from a contrast-enhanced MRA. b 3-D reconstruction of the contrast-enhanced MRA using the volume rendering technique.
Fig. 4.67 Condition after performing a Waldhausen subclavian flap aortoplasty. The proximal left subclavian artery was used for the aortoplasty of an aortic coarctation. Thus, the proximal left subclavian artery is not depicted. No relevant residual stenosis is visible, but residual collaterals are visible in the MIP reconstruction (a). The descending aorta near the anastomosis demonstrates ectatic dilatation to a maximum of 2.5 cm. a 3-D MIP reconstruction, lateral projection, of a contrast-enhanced MRA. b 3-D volume rendering of a contrast-enhanced MRA.
Fig. 4.68 Formation of an aneurysm after a Vossschulte patch aortoplasty. Depiction of the thoracic aorta of three different patients after placing an indirect aortoplasty patch made of foreign materials (Vossschulte patch aortoplasty). The 3-D volume rendering of a contrast-enhanced MRA (a), like the 3-D volume rendering of a CTA (b), shows a typical complication of this surgical technique, namely the development of an aneurysm (a, b, arrows) near the patch aortoplasty. In addition to the patient’s condition after a Vossschulte patch aortoplasty, the 3-D MIP reconstruction of an MRA still depicts a hypoplastic aortic arch (c, double asterisk). For this reason, an extra-anatomical bypass of the ascending aorta was attached to the descending aorta, without any relevant residual restenoses or aneurysm formation. AAo = ascending aorta B = bypass DAo = descending aorta PA = pulmonary artery a 3-D volume rendering of a contrast-enhanced MRA. b 3-D volume rendering of a CTA. c MIP reconstruction of a contrast-enhanced MRA.

In very rare cases of elongated stenoses, tubular prosthetic conduits made of foreign materials are implanted. In cases of high-grade stenoses with a potentially poor prognosis for end-to-end anastomosis, extra-anatomical bypasses made of various materials may be placed (▶Fig. 4.69).

Fig. 4.69 Extra-anatomical bypass in a case of high-grade aortic coarctation. The images a, b, and d depict the non-resected, high-grade native aortic isthmus stenosis (a, b, d, asterisk) in a 29-year-old man. The aortic coarctation was treated using an extra-anatomical bypass (a-e, arrows) from the left subclavian artery to the descending aorta. Though normal maximum flow velocities (d) are visible in d and e, pronounced vortex formation (e) is also visible. The vortex formations in the bypass were calculated using 4-D MR flow measurement. a 3-D volume rendering of a contrast-enhanced MRA. b Sagittal MIP reconstruction of a contrast-enhanced MRA. c Curved reformat, with centerline, of a contrast-enhanced MRA. d Visualization of 4-D flow: here, the maximum flow velocities were depicted. e Visualization of 4-D flow: here, the vortices (vortex formations) were depicted.

During a subclavian flap aortoplasty, the aortic isthmus is dilatated via the left subclavian artery (▶Fig. 4.67). The artery is disconnected, its origin is folded downward, and it is used as an enlargement patch (▶Fig. 4.70). Then, the remaining distal subclavian artery is supplied via collateral circulation (▶Fig. 4.70d). As a result of this intervention, however, the patient’s left arm generally lags behind the right arm in terms of growth, and thus is somewhat shorter.

Fig. 4.70 Condition after subclavian flap aortoplasty. Forty-three-year-old male patient after an aortic coarctation operation with a Waldhausen subclavian flap aortoplasty and aneurysm formation, which was treated by placing a thoracic aortic stent. No stent fracture is detectable. a CT topographic image in a.-p. orientation. b Transverse reconstruction of a multi-slice CT data set. c Coronal reconstruction of a multi-slice CT data set. The thrombosed aneurysm segment left lateral to the stent, which was caused by the stent, is clearly visible. d 3-D volume rendering of a multi-slice CT data set. The surgically “disconnected” left subclavian artery, which is now supplied via the carotid-subclavian bypass (arrow), is clearly visible.

Aortic coarctation is often associated with hypoplasia of the aortic arch. It must be surgically enlarged via a median thoracotomy using a heart–lung machine and selective head perfusion, or supplied by means of a bypass from the ascending aorta to the descending aorta (▶Fig. 4.68c).


Balloon angioplasty has become the treatment of choice for older children, adolescents, and adults, particularly for short stenoses. For adolescents and adults, this is generally combined with stent placement (▶Fig. 4.71). The stenosis is often dilated gradually using balloons 2.5–3 times the diameter of the isthmus, though no larger than the diameter of the aorta near the diaphragm or of the pre-stenotic aortic arch. 72

Fig. 4.71 Stent placement in a case of high-grade aortic coarctation. Thirty-nine-year-old female patient with high-grade aortic coarctation (a, asterisk) and pronounced collateralization via the mammarian and intercostal arteries. a 3-D MIP reconstruction of a contrast-enhanced MRA before implantation. b 3-D volume rendering from a CTA after stent implantation.


Postoperative and Postinterventional Issues

This surgery carries the risk of damaging the phrenic and recurrent nerves, resulting in unilateral paralysis of the diaphragm or vocal cords. In rare cases, the thoracic duct can also be damaged, leading to subsequent chylothorax. In even rarer cases, paraplegia of the lower extremities (also known as post-coartectomy syndrome) can occur. The restenosis rate after surgery is high, namely 5–10% in older children (▶Fig. 4.66). For cases of critical aortic coarctation or aortic arch hypoplasia (▶Fig. 4.68c), however, this rate is substantially higher. 73 , 74


Catheter interventions carry the risk of damage near the arterial vascular access (bleeding, thrombosis, aneurysms). Dilatation can also cause the aorta to rupture or aneurysms or dissections to form, though only in rare cases. If a stent is placed, there is a risk of stent fracture, stent dislocation, or restenosis caused by neointima formation near the stent.


Over the long term, this can lead to restenosis, aneurysm formation, or persistent arterial hypertonia in a not inconsequential number of patients. Patients with associated bicuspid aortic valve have an elevated risk of restenosis or ectasia of the ascending aorta, and patients have an elevated risk of developing aneurysms near the surgical site after aortic arch or patch aortoplasty, particularly if foreign materials were used (▶Fig. 4.68). 75 , 76



Note

Arterial hypertonia is often still present immediately after aortic coarctation treatment and persists in up to 50% of patients without evidence of relevant residual stenosis or restenosis.


The lack of elasticity in the aortic arch and associated hemodynamic changes are believed to be the cause of this persistent arterial hypertonia. Thus, consistent antihypertensive treatment should be given. 77



Goals and Relative Value of Diagnostic Imaging

For infants and small children, echocardiography is the imaging method of choice due to the generally good acoustic window. In particular, this technique can be used to depict the degree of stenosis, a potentially open ductus arteriosus, left ventricular function, and associated defects. Ideally, the aortic arch is depicted via a suprasternal or jugular acoustic window (▶Fig. 4.63) when using cranial extension, or from a right parasternal view.


For older children, adolescents, adults, and especially for patients with previous surgeries, echocardiographic depiction can be significantly restricted by the limited acoustic window. In these cases, MRI and particularly contrast-enhanced MRA (including 3-D reconstruction) are the modalities of choice (▶Fig. 4.64c and d), followed by multi-slice CT (▶Fig. 4.72; also ▶Fig. 4.68b). Both of the former allow detailed depiction of the stenosis, collaterals, left ventricular function and mass, and associated defects, as well as aneurysms or restenosis in previously treated patients. Particularly after stent placement (▶Fig. 4.70 and ▶Fig. 4.71), multi-slice CT is superior to MRI if there is evidence of restenosis caused by neointima formation or stent fractures. Although performing an MRI after stent placement in the aorta is not contraindicated, and many stents (particularly nitinol ones) only generate minor artifacts, MRI quality near the stent is still limited. MRI can be used for precise quantification of an associated bicuspid aortic valve andO any stenoses it may have caused, as well as aortic valve insufficiency and ventricular function. MRI flow measurement is suited to determining the extent of collateralization of the aortic coarctation. In cases of very high-grade, subtotal stenoses, collateral flow can be significantly higher than that in the aorta immediately distal to the stenosis. This can be depicted well using 4-D flow measurement (▶Fig. 4.72). This method can also be used to estimate the relevance of a restenosis. 78 , 79 In the future, new 4-D MRI flow measurement technologies 80 could also be helpful for planning optimal surgical techniques in order to restore physiological flow, if possible (▶Fig. 4.69). Just like Doppler echocardiography, MRI also allows instantaneous pressure gradients to be estimated by determining maximum flow velocity in the stenosis by means of MRI flow measurement and the phase contrast technique, and by using the simplified Bernoulli equation. This correlates well to invasively measured pressure gradients, at least for minor-to-moderate stenoses. 78

Fig. 4.72 High-grade aortic coarctation with collateral formation. Patient with high-grade, sub-total aortic coarctation (a–c, asterisks) and pronounced collateral formation. 4-D MR flow measurement reveals that no relevant flow via the stenosis can be demonstrated either during systole or diastole, though pronounced, primarily diastolic collateral flow is present (a–c, arrows). a 4-D MR flow measurement with reconstruction of the maximum flow velocities during systole. b 4-D MR flow measurement with reconstruction of the maximum flow velocities during diastole. During diastole, the descending aorta is supplied primarily by collateral flow. c 3-D volume rendering reconstruction of a CTA, dorsal view.


Note

All tomographic procedures measure the diameter of the ascending aorta, the transverse and distal aortic arch, and the descending aorta distal to the stenosis. The length of the stenosis, as well as any potentially associated vascular anomalies (head and neck vessels, renal arteries) or collaterals are determined. This is decisive for treatment planning purposes. 62


Often, the thoracic X-ray in p.-a. projection depicts an aortic coarctation in adults due to the typical rib notches, shallow recesses on the inferior margins of the third–eighth dorsal ribs (▶Fig. 4.64a). Otherwise, heart size is generally normal and only enlarged in cases of critical aortic coarctation. X-rays depict signs of pulmonary obstruction. Due to this pre-stenotic enlargement of the left subclavian artery generally present near the aortic coarctation (▶Fig. 4.64, ▶Fig. 4.66, ▶Fig. 4.72) and the post-stenotic enlargement of the descending aorta, X-ray or angiographic images depict a typical left-side “notch,” the image of a double aortic knob. In principle, Doppler echocardiography and tomographic procedures are used for preoperative diagnostics. A postinterventional stent fracture, however, can also be recognized on a simple X-ray p.-a./lateral image (▶Fig. 4.70a).


An invasive cardiac catheter examination is indicated for precise quantification and invasive measurement of the pressure gradient (▶Table 4.22). Generally speaking, the decision to perform surgical or interventional treatment can occur noninvasively using Doppler echocardiography and/or MRI or multi-slice CT tomographic procedures. To that end, invasive diagnostics are usually only performed if an interventional treatment (namely, balloon angioplasty or stent placement) is also anticipated. 81 However, there are already initial case studies using MRI-guided aortic coarctation treatment with fluoroscopy as a backup. 82



























































































Table 4.22 Relative value of individual imaging procedures for assessing various aspects of aortic coarctation.

Findings


Echocardiography


Thoracic X-ray, p.-a./lateral


MRI with flow measurement


MDCT


ECG-triggered


Cardiac catheter (angiography and hemodynamics)


TTE


TEE


3-D


Aortic arch morphology


high



moderate



high


high


high


Associated cardiac defects


high


high


high



high


moderate


high


Isthmus stenosis graduation

             



  • Morphological


high



high



high


high


high




  • Functional


high





high


low


high


Left ventricular function


high


high


high



high


moderate


high


Myocardial morphology


high


high




high


high


moderate


ECG, electrocardiography; MDCT, multidetector computed tomography; MRI, magnetic resonance imaging; TEE, transesophageal echocardiography; TTE, transthoracic echocardiography.


Table 4.22 compares the relative value of imaging procedures.



Note

The MRI and multi-slice CT tomographic procedures are each class I2 indications for diagnosing a coarctation, meaning the diagnostic precision is comparable to that of other diagnostic methods. 7



4.3.3 Interrupted Aortic Arch

Joachim Lotz, Joachim G. Eichhorn, Michael Steinmetz

Definition

This rare congenital defect is characterized by a complete interruption between two segments of the aortic arch (interrupted aortic arch, IAA), which are, at most, still connected via residual connective tissue, but possess no vascular connection to one another (like in cases of aortic isthmus atresia). Unlike aortic coarctation, IAA is a rare congenital heart defect, comprising less than 0.1% of all heart defects. In theory, the aortic arch can be interrupted at any point (▶Fig. 4.73), regardless of whether a left or right arch is present. 83

Fig. 4.73 Three most common types of IAA. Schematic depiction. AAo = ascending aorta DAo = descending aorta LCCA = left common carotid artery LPA = left pulmonary artery LSA = left subclavian artery MPA = main pulmonary artery (truncus pulmonalis) PDA = patent ductus arteriosus RCCA = right common carotid artery RPA = right pulmonary artery RSA = right subclavian artery


Classification

The interruption is classified as one of three types based on its location from distal to proximal (▶Fig. 4.73). Frequency is indicated using the system developed by Schumacher et al.: 83




  • Type A: Interruption distal to the origin of all head and arm vessels (approximately 40% of cases)



  • Type B: Interruption between the left subclavian artery and the left carotid artery (approximately 55% of cases)



  • Type C: Interruption between the left carotid artery and the brachiocephalic trunk (this is mirrored for right-side aortic arch, namely, between the right carotid artery and right subclavian artery; approximately 5% of cases)


An isolated form occurs only in about 3–4% of cases, 83 , 84 most of which are type A. Otherwise, a number of primarily left-side defects with concurrent PDA and VSD, bicuspid aortic valve and more complex defects such as TGA, truncus arteriosus, or even HLHS have been described.



Hemodynamics and Clinical Issues

“Ductal-dependent” systemic circulation is common to all types. In these cases, antegrade perfusion occurs via the descending aorta and thus all circulation in the lower body occurs solely via a PDA. Depending on the location of the interruption, the distal head and arm vessels may be supplied via the PDA and retrograde perfusion via the distal arch segment. Due to the left–right shunt through the PDA, affected children begin to display clinical symptoms caused by a difference in transcutaneously measured oxygen saturation (with a lower value in the lower extremities and a normal value in the right hand), provided that these measurements are taken during screenings. Physiologic closure of the PDA is fatal to these patients, and correlates to additional clinical symptoms. Nevertheless, an IAA can also first manifest itself clinically in adulthood. 84 , 85



Treatment

Like in cases of HLHS, a prostaglandin E infusion can be used to enlarge the PDA or hold it open, though this is a temporary, emergency treatment. If possible, surgical treatment should occur as a single intervention in newborns (namely an end-to-end anastomosis, subclavian artery angioplasty, or prosthetic interposition), based on the concurrent defects and the length and localization of the interruption. As mentioned, the mortality rate remains high. 83



Diagnostics and the Role of Imaging Procedures

Though fetal echocardiography can be used to diagnose this condition prenatally, the condition is not apparent in many patients until after birth, not infrequently after the patient has entered cardiogenic shock. In less severe cases with only partial ductal closure, symptoms may closely resemble those of a preductal aortic coarctation. In theory, it is also possible to use MRI for prenatal diagnosis. 86


Thoracic X-rays often depict pronounced cardiomegaly caused by the pronounced right–left shunt. A diagnosis cannot, however, be determined using thoracic X-rays.


Final diagnosis is usually determined solely using TTE. The interruption can often be depicted clearly from a suprasternal view. In mild cases, a tomographic method is preferable to a cardiac catheter examination. Despite the radiation exposure, 84 , 85 , 87 CT is preferable to MRI in critically ill patients due to the speed of the former method (▶Fig. 4.74). For hemodynamically stable children, MRI should be used in order to reduce radiation exposure.

Fig. 4.74 Type A IAA. Two-week-old infant in overall poor clinical condition, with a systolic blood pressure difference > 35 mmHg between the upper and lower extremities. AAo = ascending aorta COLL = collaterals DAo = descending aorta LCCA = left common carotid artery LSA = left subclavian artery MPA = main pulmonary artery (truncus pulmonalis) RCCA = right common carotid artery a A.-p. 3-D reconstruction of a CTA. The ascending aorta is divided into the right and left common carotid arteries. The transverse and descending segments of the aortic arch are absent. The right subclavian artery (asterisk) originates dorsally to the right common carotid artery. The aorta continues as a descending aorta with collaterals supplied by cranial flow, which are supplied by the left vertebral and paravertebral arteries, left-dorsally to the ectatic pulmonary arterial stem. b P.-a. 3-D reconstruction of a CTA. From a dorsal view, the descending aorta (which is supplied by the left vertebral arteries and paravertebral collaterals and has no direct connection to the ascending aorta) is clearly visible left-lateral to the spinal column. The ductus arteriosus, which ensures perfusion of the lower half of the body both prenatally and immediately postnatally, is closed after 14 days. This explains the delayed onset of clinical symptoms. The left subclavian artery originates from the collateral stem as a tiny vessel.

In addition to diagnosing and classifying the IAA, it is beneficial to determine the course of the interruption or length of atresia, as well as its spatial relationship to airways (trachea and main bronchus) and to the esophagus prior to surgery. The often-variable origin of the left subclavian artery is important for preoperative planning. 83


Postoperative management must include not just an assessment of cardiac function, but must also rule out or quantify any restenoses and assess their hemodynamic significance. If a larger distance must be bridged surgically (and the distal arch pulled far to the front), this can lead to bronchial compression. Thus, if clinical symptoms include airway obstruction, bronchial compression must be ruled out definitively.


The preoperative and postoperative value of the various imaging procedures depends on the concurrent illnesses paramount to the aortic coarctation (▶Table 4.22). In the future, 4-D MRI will likely also provide additional insights into altered preoperative and postoperative hemodynamic situations in cases of IAA. 88



4.4 Complex Defects



4.4.1 Transposition of the Great Arteries

Matthias Gutberlet, Christian Kellenberger

Definition

In cases of TGA, a discordant ventriculoarterial connection is present, in which the outflow tracts of the right and left ventricles run parallel to one another (▶Fig. 4.75) rather than crossing (as occurs in normal anatomy). 83 , 89 91 Thus, the aorta originates partially or fully from the morphologic right ventricle, and the pulmonary artery, from the morphologic left ventricle, respectively.

Fig. 4.75 Schematic depiction of the forms of TGA. AAo = ascending aorta Ao = aorta AV = aortic valve DORV = double outlet right ventricle D-TGA = dextro-transposition of the great arteries LA = left atrium LPA = left pulmonary artery L-TGA = levo-transposition of the great arteries LV = left ventricle mLV = morphologic left ventricle mRV = morphologic right ventricle MV = mitral valve PA = pulmonary artery (truncus pulmonalis) PV = pulmonary valve RA = right atrium RPA = right pulmonary artery RV = right ventricle SVC = superior vena cava THY = thymus TV = tricuspid valve VSD = ventricular septal defect a Schematic depiction of the parallel arrangement of the ventricular outflow tracts. b Schematic depiction of the arrangement of the great vessels (aorta and pulmonary arteries) with respect to one another near the valve, showing various pathologies of the great vessels compared to normal clinical findings (normal). c Schematic TTE depiction of the appearance of a TGA, or complete transposition of the great arteries. Note the muscular conus (c, d, asterisk) around the RVOT and the position of the aortic valve compared to the pulmonary valve. The double asterisks in c and d indicate the moderator band, which is defined as one of the numerous characteristics of the morphologic right ventricle. d Schematic depiction of the appearance of a ccTGA, TTE image. e TTE image of a newborn with TGA IVS, or complete transposition of the great arteries with intact interventricular septum. The connection of the aorta to the right ventricle and of the main pulmonary artery to the left ventricle are visible along the parasternal long axis. The outflow tracts do not cross one another. f TTE image of the same newborn as in e. 2-D echocardiography image, suprasternal transthoracic view of the great vessels. Good acoustic window, thymus clearly visible. The right-anterior origin of the ascending aorta and the left-posterior origin of the main pulmonary artery branching into the right and left pulmonary arteries is visible in f and g. g TTE image of the same newborn as in e and f. Color Doppler echocardiography.

In the case of a normal atrioventricular connection between the right atrium and the morphologic right ventricle, a developmental disorder of the embryonic conotruncus is present. These cases are described as complete transposition of the great arteries with intact interventricular septum (TGA IVS—often simplified to D-TGA), because the RVOT and thus also the ascending aorta are displaced to the right (“D” stands for “dextro-,” ▶Fig. 4.75).


Ventricular inversion is present if an anomalous atrioventricular connection between the morphologic right ventricle and morphologic left atrium also occurs. The TGA is then considered “congenitally corrected” and is thus also known as “congenitally corrected transposition” (ccTGA, colloquially often also called L-TGA), 91 since, in these cases of ventricular inversion, the ascending aorta generally (in up to 85% of cases 83 ) originates left of the pulmonary artery from the left-displaced, morphologic right ventricle (“L” stands for “levo-,”; ▶Fig. 4.76 and ▶Fig. 4.77; also ▶Fig. 4.75b). However, the correct nomenclature for this congenital heart defect is ccTGA.

Fig. 4.76 L-TGA. MRI of a 40-year-old, previously asymptomatic male patient with ccTGA. AAo = ascending aorta mLV = morphologic left ventricle mRV = morphologic right ventricle PA = pulmonary artery a SSFP cine. Transverse plane. The levoposition of the aorta compared to the pulmonary artery is visible the origin of the great vessels. b Coronal plane of a black blood SE sequence. Typical parallel positioning of the ascending aorta and the main pulmonary artery, which originates from the right-displaced, morphologic left ventricle. The left-displaced, morphologic right ventricle is characterized by a muscular conus (white arrow). c Moderator band (asterisk) and significant right ventricular trabeculation.
Fig. 4.77 L-TGA. Various reconstructions of a 4-D MDCT data set (64 rows), acquired using retrospective gating in a 72-year-old male patient with ccTGA and pronounced tricuspid valve insufficiency, before a potential tricuspid valve reconstructive procedure. AAo = ascending aorta L = left coronary semilunar valve LA = left atrium LAD = left anterior descending artery LV = left ventricle mLV = morphologic left ventricle mRV = morphologic right ventricle P = posterior semilunar valve PA = pulmonary artery R = right coronary semilunar valve TV = tricuspid valve a Reconstruction, 4-chamber view, depicting the moderator band (double asterisk) of the significantly dilated, left-displaced, morphologic “right” systemic ventricle with pronounced trabeculation. b Long-axis reconstruction depicting the subaortic muscular conus (asterisk). c The transverse reconstruction depicts the typical L-TGA position of the aorta and pulmonary artery to one another. Minor insufficiency of the tricuspid aortic valve is visible. As most commonly described, 83 the right coronary artery originates near the posterior semilunar valve and supplies the morphologic right ventricle on the left side and the left anterior descending artery (LAD) and the circumflex (CX) from the area to the left coronary semilunar valve (▶Fig. 4.77e) and supply the morphologic left ventricle on the right side. d The short-axis reconstruction depicts the left-displaced tricuspid valve, opened during diastole, from a direct frontal view. e 3-D volume rendering depicting coronary supply of the left-displaced, morphologic right ventricle. f The strong trabeculation of the morphologic right ventricle is most prominent in the short-axis reconstruction of a midventricular slice. The green area indicates the segmented muscle mass measured automatically by the software. Since not all trabeculae were recognized automatically, additional manual correction is necessary to accurately determine muscle mass. g 2-D TTE, 4-chamber view, with the morphologic right ventricle meant to be identified using the moderator band (asterisk). h A holosystolic insufficiency jet in a case of high-grade tricuspid valve insufficiency (arrow) is visible in color Doppler. i Maximum flow velocity of 4.96 m/s through the tricuspid valve was determined using spectral Doppler.


Note

In cases of ccTGA, the morphologic right ventricle and its tricuspid valve (▶Fig. 4.77d) are located on the left side, except for in cases of situs inversus (▶Fig. 4.78). The left-displaced aorta then originates from the morphologic right ventricle (▶Fig. 4.76a,c and ▶Fig. 4.77c,e). The morphologic right ventricle is supplied by the normal left atrium (▶Fig. 4.77a). Morphological characteristics of the right ventricle include the following:

Fig. 4.78 ccTGA. Twenty-five-year-old female patient with situs inversus and ccTGA. AAo = ascending aorta DAo = descending aorta mLV = morphologic left ventricle mRV = morphologic right ventricle PA = pulmonary artery SVC = superior vena cava a Narrow vascular band (arrow) in a traditional p.-a. thoracic X-ray, caused by the directly retrosternal and almost parallel position of the great vessels. b Various axial slices from an SSFP cine MRI. Top left, the typical parallel position of the great vessels. Top right and bottom right, a prominent moderator band (triple asterisk). Bottom left, a muscular conus (asterisk) surrounding the aorta. Bottom right, a left-displaced liver (double asterisk, refer to the double asterisk in a).

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May 7, 2020 | Posted by in CARDIOVASCULAR IMAGING | Comments Off on 4 Clinical Pictures
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