Small Bowel Transplantation—A Clinical Review Yaron Niv, M.D., Eythan Mor, M.D., and Andreas G. Tzakis, M.D. Departments of Gastroenterology and Transplantation, Rabin Medical Center, Beilinson Campus, Tel-Aviv University, Petach-Tikva, Israel; and Division of Transplantation, Jackson Memorial Medical Center, University of Miami, Miami, Florida ABSTRACT The results of small bowel transplantation improved in the last 5 yr because of the development of new immunomodu- lating drugs and surgical techniques, as well as better can- didate selection. We still need much experience until this procedure will be in routine use for terminal intestinal insufficiency. (Am J Gastroenterol 1999;94:3126 –3130. © 1999 by Am. Coll. of Gastroenterology) INTRODUCTION Experimental animal models for small bowel transplantation (SBTx) were developed already 20 yr ago (1, 2), but the initial clinical experience yielded high morbidity and mor- tality rates (3, 4). Its rich lymphatic tissue makes the small bowel highly vulnerable to rejection and serves as a source for aggressive graft versus host reaction. In the last 5 yr, the development of new immunomodulating drugs and surgical techniques in solid organ transplantation (Tx), as well as better candidate selection, have improved the results of SBTx, though they are still far from ideal (5). Intestinal transplantation remains the only available treatment for pa- tients with intestinal failure and complications of underlying disease and/or total parenteral nutrition (TPN). However, the factors affecting long term survival are not well known because the number of successful transplantations per- formed worldwide is still relatively small and the follow-up is limited. According to the International Intestinal Trans- plant Registry (6), as of February 1997, the 33 transplanta- tion centers performed 273 SBTxs in 260 patients: 113 solitary small bowel, 130 combined small bowel and liver, and 30 organ clusters (stomach, duodenum, pancreas, and liver). INDICATIONS FOR SMALL BOWEL TRANSPLANTATION SBTx is performed in patients with terminal intestinal in- sufficiency, i.e., irreversible failure of the intestine to cover the nutritional needs of the patient. Intestinal failure is most commonly due to short gut syndrome (after extensive re- section of the intestine) or, less frequently, to motility or absorption disorders. Patients have been considered as can- didates for the SBTx when they can no longer be supported by TPN because of complications of their disease or TPN. The latter include depletion of central venous access and cholestatic liver disease. Patients with these complications are often terminally ill and have contributed to the histori- cally poor survival rate after these procedures. As the ex- perience increases and results improve, patients are consid- ered earlier in the course of the disease. In adults, common causes of intestinal failure and trans- plantation have been Crohn’s disease, Gardner’s syndrome, abdominal trauma, and hypercoagulable states resulting in diffuse splachnic thrombosis. Transplantation of a pheno- typically healthy liver will usually also correct the under- lying abnormality (protein C and S, and antithrombin III deficiency). Thrombosis of the central veins (as in hyper- coagulability syndrome) and recurrent catheter sepsis are the main indications for SBTx. In children, the indications are usually congenital disorders (atresia, gastroschisis, vol- vulus) and necrotizing enterocolitis. The specific indications for 185 procedures reported in the medical literature are shown in Table 1 (5). Although hyperalimentation prolongs survival, the long term survival rate is low. This is especially true in the pediatric group, which comprises almost 50% of small bowel transplant recipients for short bowel syndrome. A major cause of death in this group is hepatic failure due to cholestasis and recurrent sepsis (7). PREPARATION FOR TRANSPLANTATION AND SURGICAL APPROACH The main requirement for SBTx is ABO-blood type match- ing. Blood type mismatch may cause severe hemolysis, explained by graft versus host disease (GVHD), or severe acute rejection (8). Better results have been reported when the cytomegalovirus (CMV) serology status was also matched, namely, by giving a negative CMV graft to a negative CMV recipient (9). The “ideal” donor is 50 yr, without infection, and hemodynamically stable. The opera- tion in the donor is aimed at multiple organ harvesting. According to the particular need, one can use only the small bowel, the liver and the small bowel, or an abdominal organ cluster. Like other abdominal organs, the small bowel is preserved in University of Wisconsin solution for up to 16 h (10). The surgical approach in the recipient depends on the THE AMERICAN JOURNAL OF GASTROENTEROLOGY Vol. 94, No. 11, 1999 © 1999 by Am. Coll. of Gastroenterology ISSN 0002-9270/99/$20.00 Published by Elsevier Science Inc. PII S0002-9270(99)00562-6