(See also Overview of Transplantation.)
Small-bowel transplantation is done infrequently (eg, about 106 transplants in the US in 2012). It is being done less frequently because there are new treatments for secondary cholestatic liver disease (eg, Omegaven®, a nutritional supplement rich in omega fatty acids) and safer TPN line placement techniques.
Small-bowel transplantation is indicated for patients who
Are at risk of death because of intestinal failure secondary to intestinal disorders (eg, gastroschisis, Hirschsprung disease, autoimmune enteritis, congenital enteropathies such as microvillus inclusion disease) or intestinal resection (eg, for mesenteric thromboembolism or extensive Crohn disease)
Develop complications of TPN used to treat intestinal failure (eg, liver failure secondary to cholestatic liver disease, recurrent sepsis, total loss of venous access)
Have locally invasive tumors that cause obstruction, abscesses, fistulas, ischemia, or hemorrhage (usually desmoid tumors associated with familial polyposis)
Procurement from a brain-dead, beating-heart donor is complex, partly because the small bowel can be transplanted alone, with a liver, or with a stomach, liver, duodenum, and pancreas. The role of living-related donation for small-bowel allografts has yet to be defined.
Procedures vary by medical center; immunosuppressive regimens also vary, but a typical regimen includes antilymphocyte globulin for induction, followed by high-dose tacrolimus and mycophenolate mofetil for maintenance.
Weekly endoscopy is indicated to check for rejection. About 30 to 50% of recipients have one or more bouts of rejection within the first year after transplantation.
Symptoms and signs of rejection include diarrhea, fever, and abdominal cramping. Endoscopic findings include mucosal erythema, friability, ulceration, and exfoliation; changes are distributed unevenly, may be difficult to detect, and can be differentiated from cytomegalovirus enteritis by viral inclusion bodies. Biopsy findings include blunted villi and inflammatory infiltrates in the lamina propria (see Table: Manifestations of Small-Bowel Transplant Rejection by Category).
Treatment of acute rejection is high-dose corticosteroids, antithymocyte globulin, or both.
At 3 yr, survival rates after small-bowel transplantation alone are
Infections commonly contribute to death.
With liver and small-bowel transplantation, survival rates are lower because the procedure is more extensive and the recipient’s condition is more serious. However, after the perioperative phase, graft and patient survival rates are higher than those after small-bowel transplantation alone, presumably because the transplanted liver has a protective effect, preventing rejection by absorbing and neutralizing antibodies.