Surgical Considerations for Congenital Heart Disease

Asvin M. Ganapathi and Andrew J. Lodge

Congenital cardiac defects may be categorized in a variety of ways. One approach is to separate them based on the presence or absence of cyanosis in the patient presenting to the pediatric cardiologist or cardiac surgeon. Cyanotic lesions are associated with shunting of deoxygenated blood into the systemic arterial circulation or with severely reduced pulmonary blood flow. These lesions include transposition of the great arteries, tetralogy of Fallot (TOF), truncus arteriosus, total anomalous pulmonary venous connection, and hypoplastic left heart syndrome (HLHS). Acyanotic lesions include (1) obstructions to left ventricular outflow, such as aortic stenosis or coarctation of the aorta, and (2) defects with shunting of blood from the systemic circulation to the pulmonary circulation, including atrial, ventricular, and atrioventricular septal defects and patent ductus arteriosus (PDA). Often a combination of lesions exists, and associated anomalies must be thoroughly identified by preoperative imaging studies. This chapter will review the pathophysiology and clinical and imaging evaluation of patients with congenital heart disease as they relate to surgical planning. Discussion will reference treatments, particularly with regard to choice of surgical approach, along with intraoperative and postoperative considerations pertinent for radiologists.

General Considerations

Many congenital heart defects are fatal if they are not corrected surgically. Other defects can lead to long-term complications or a shortened life expectancy if timely surgical treatment is not undertaken. Surgery for congenital heart disease has advanced quite rapidly in the past several decades, with progress in surgical techniques and instrumentation and substantial improvements in anesthesia, critical care, and diagnostic imaging. As a result, many congenital heart defects can be treated effectively, with consistently improving results.

Surgical Approaches

Surgery for congenital heart disease is most commonly performed via a median sternotomy incision. Such an incision involves an anterior midline thoracic incision with dissection through the subcutaneous tissues down to the sternum. Once the sternum has been exposed, a sternal saw is used to split the sternum and a retractor is placed to define the operative field within which the pericardial sac is contained (Fig. 70-1). Because this incision offers excellent access to all of the structures contained within the mediastinum, including all chambers of the heart, ventricular outflow tracts, and venous returns, it is useful when multiple lesions are present or if a complicated repair must be performed.

Figure 70-1 Median sternotomy.
A, A sternal retractor is in place in a patient with transposition of the great arteries. The pericardium has been opened and sutured to the margins of the incision to expose the heart. The aorta (Ao) arises from the right ventricle (RV) and the pulmonary artery (PA) from the left ventricle. The left coronary artery and some of its branches also are seen. Note that the left ventricle, which is a posterior structure, is not well exposed. B, Similar exposure in a patient with hypoplastic left heart syndrome. The main PA is large and the ascending aorta (AA) is diminutive. The right pulmonary artery (RPA) is visible emerging from behind the aorta. The right atrial appendage is being grasped with a forceps. The right ventricle (RV) is also exposed. The cut pericardial edge, which is sutured to the skin edge, is more easily seen in this picture.

Less invasive options for repair of congenital heart lesions also exist, such as a partial median sternotomy or a thoracotomy. In the case of a partial median sternotomy, the skin incision is kept small and only the upper or lower sternum is divided (e-Fig. 70-2). Depending on the necessary exposure, thoracotomy incisions can be anterior, lateral, or posterior (e-Fig. 70-3). Historically, thoracotomy incisions involved the sectioning of a rib; in general these incisions now are made simply by dividing the intercostal muscles and leaving the ribs intact.

e-Figure 70-2 Partial lower median sternotomy.
A, With the patient supine and the head to the left of the picture, the skin is marked preoperatively to show the length of the entire sternum, the second and third intercostal spaces (2 and 3), and the planned incision between the horizontal lines. In small children, a skin incision approximately 4 cm long can be used. B, The exposure created with this incision is shown. Compared with Figure 70-1, less of the pericardial contents are immediately obvious. C, The closed incision following repair of an atrial septal defect. A chest tube and pacing wires are seen exiting the skin caudal to the incision.

e-Figure 70-3 Anterior right thoracotomy incisions for minimally invasive heart surgery.
The incisions are generally made in the inframammary crease. These incisions sometimes are preferred, particularly for female patients.

The type of lesion being repaired determines the choice of surgical incision. Straightforward repair of extracardiac lesions such as aortic coarctation, vascular rings, or PDA generally can be performed through a left thoracotomy (e-Fig. 70-4). In addition, in the case of simple intracardiac repairs such as an atrial septal defect (ASD), a minimally invasive approach can be used even though the operation requires the use of cardiopulmonary bypass (CPB). As techniques have been refined in recent years, interest has increased in operating on simple defects, as well as the mitral, tricuspid, and aortic valves, through minimally invasive incisions. In addition, interest has developed in performing relatively straightforward operations, including some heart valve surgery, using thoracoscopic or robotic techniques. In these cases, several very small incisions are made through which specially designed instruments can be placed and used to perform the procedure (e-Fig. 70-5). Advantages touted include an improved cosmetic result and potentially shorter recovery times inside and outside the hospital.

e-Figure 70-4 Aortic coarctation.
A, Aortic arch, ductus arteriosus (vessel with two sutures encircling it), and aortic coarctation (vessel with single stay suture). Narrowing of the aortic isthmus occurs just proximal to the insertion of the ductus. B, The coarctation repair is complete. The ductus arteriosus has been ligated and divided, the coarctation has been excised, and the proximal and distal segments of the aorta have been connected with an extended end to end anastomosis. (Copyright 2010 CTSNet, Inc. All rights reserved. Image (http://www.ctsnet.org/sections/clinicalresources/congenital/expert_tech-.htm) is reproduced by permission of CTSNet, Inc.)

e-Figure 70-5 Incision sites for robotic ports used in atrial septal defect repair.

For most complex congenital heart defects, such as repair of an atrioventricular (AV) septal defect lesion, a median sternotomy is used. In this case the repair includes a right atriotomy, closure of a ventricular septal defect (VSD), repair of the ASD, and partitioning of the common AV valve into right and left components, with closure of the “cleft” in the left-sided AV valve (e-Fig. 70-6). Additionally, repair of cyanotic lesions typically requires the use of a median sternotomy incision. The reasoning is that these lesions often require greater exposure of both intracardiac and extracardiac structures that need to be repaired. One example of the need for a median sternotomy incision is a repair in a patient with TOF where an approach through the right atrium and the pulmonary artery is needed to close the VSD and relieve the right ventricular outflow obstruction. In some cases in which a very small pulmonary annulus or significant infundibular stenosis is present, the incision might even need to be extended to the right ventricular cavity (e-Fig. 70-7).