Small Intestine Transplantation

 Usually for liver failure due to chronic TPN



• Donor bowel has copious lymphoid tissue and bacteria
image Higher prevalence of rejection and infectious complications than solid visceral transplants




IMAGING




• Vascular complications: Thrombosis, stricture, pseudoaneurysm (arteries or veins)
image Less common than for other transplant procedures

• Mesenteritis: Present to some degree in all SB transplantation recipients

• Opportunistic infections: May affect any organ including allograft

• Pneumatosis: Usually not due to ischemia

• Ascites: Usually loculated, nonspecific finding
image Chylous ascites: Presence of fat-fluid levels

• Posttransplantation lymphoproliferative disorder (PTLD)
image More common in SB (up to 30%) and multivisceral Tx than most other solid organ transplant recipients

image More common within SB allografts than in host organs

• Rejection and graft-vs.-host disease
image Both common, cannot be distinguished on imaging

• Dilation of SB lumen
image May result from dysmotility, adhesion, ischemia, or rejection

• Imaging protocols: Multiplanar CT, ± CT angiography, displays most important anatomical and pathophysiological information pertinent to small bowel Tx

• Upper GI series to evaluate motility and status of proximal bowel anastomosis


CLINICAL ISSUES




• SB Tx: 1-year patient survival (90%); graft survival (∼ 75%)
image Multivisceral Tx: 1-year patient survival (80%)

image 5-year patient survival: 60%

• Worse than for solid organ transplant recipients

image
Graphic demonstrates some of the altered anatomy in a small bowel transplantation (SB Tx) procedure. The small bowel allograft is usually anastomosed proximally to the distal duodenum or proximal jejunum of the recipient, and distally to the sigmoid image, with a temporary “chimney” ileostomy in the right lower quadrant. This ostomy allows convenient access to the allograft in the perioperative period for endoscopic visualization and biopsy procedures, and may be permanent. The donor superior mesenteric vein (SMV) is anastomosed to the host SMV or portal vein image. The donor SMA is anastomosed to the host aorta image.



TERMINOLOGY


Abbreviations




• Small bowel transplantation (SB Tx)


Indications for Small Bowel Transplantation




• Primarily for “short gut syndrome,” but also other causes of intestinal failure
image Small bowel length or function insufficient to provide adequate nutrition
– Result of various etiologies
image Superior mesenteric arterial (SMA) or venous (SMV) thrombosis with bowel ischemia, Crohn disease, midgut volvulus, familial polyposis/Gardner (especially with mesenteric desmoids)

– Much less commonly due to intestinal pseudoobstruction or other functional deficiency of small bowel

image Patients can be maintained on total parenteral nutrition (TPN) indefinitely, except for complications
– Lack of central venous access to administer TPN, TPN catheter-related sepsis, and TPN-induced cholestatic liver disease

• Indications for multivisceral transplantation (liver, ± pancreas, ± part of stomach)
image Advanced liver disease due to TPN or unrelated cause (e.g., chronic hepatitis)

image Advanced pancreatic disease

image Extensive mesenteric thrombosis (with multivisceral ischemia)

image Severe mesenteric neuropathy

• Special considerations for small bowel transplantation
image Donor intestine contains large number of immunocompetent lymphocytes in bowel wall (e.g., Peyer patches) and mesenteric nodes
– ↑ prevalence of graft-vs.-host and graft rejection

image Donor intestine contains large number of bacteria and other potential pathogens
– ↑ prevalence of postoperative infections

image Early diagnosis by imaging of graft-related complications helps to ↓ morbidity and mortality


IMAGING


General Features




• Anatomy of SB and multivisceral transplantation
image Stomach (if included, usually in multivisceral transplants)
– Donor greater curvature is preserved with gastroepiploic arteries, and donor stomach is anastomosed to proximal recipient stomach

– Usually includes donor duodenum and pancreas

image Intestine
– Most common proximal anastomosis (if not multivisceral Tx): Side-to-side donor jejunum to host duodenum or proximal jejunum

– Leftward displacement of gastric antrum and duodenum can result from surgical mobilization

– Most common distal anastomosis: Donor ileum to host sigmoid colon
image “Chimney” ileostomy at end of donor ileum (temporary or permanent)

– Percutaneous gastrostomy and jejunostomy tubes are placed initially

image Liver (if included, as part of multivisceral Tx)

image Pancreas (if included)
– With intact duodenum and SB and liver as part of multivisceral Tx (usually)

image Vasculature
– Arterial
image Isolated small bowel Tx: Donor SMA anastomosed to host aorta

image Multivisceral Tx: 10 cm portion of donor aorta is taken, with celiac trunk and SMA intact, then grafted end-to-side to host aorta

– Venous
image Isolated small bowel Tx: Donor SMV is anastomosed to host SMV or portal vein

image Multivisceral Tx: Donor and recipient IVCs may be anastomosed end-to-end

image Portal venous system from donor remains intact; transplanted en bloc

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Nov 16, 2016 | Posted by in GASTROINTESTINAL IMAGING | Comments Off on Small Intestine Transplantation

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