National sharing of cadaveric isolated intestinal allografts for human transplantation: A feasibility study

Most isolated intestinal graft losses are immunological, We conducted a pil ot, study to evaluate the feasibility of national sharing of HLA no-mismatc h allografts for cadaveric isolated intestinal transplantation. Methods. UNOS data were analyzed in a theoretical model. Part I: All solid organ donors between 1/95-8/97 who would have met criteria for bowel donati on were considered potential donors for all recipients who actually receive d isolated intestinal transplants during this period. We then determined ho w many donor intestines could have been directed to no-mismatch candidates had national sharing been in place. Donor exclusion criteria were (CMV+ don ors to CMV- recipients, hemodynamic instability, age >50, size mismatch (do nor weight greater than recipient), and obesity. Mean and median waits for transplants, as well as theoretical mean and median waits for transplants t hat would have occurred given national sharing, were calculated. Part II: W e estimated, based on registry graft survival dar;a, the number of intestin al transplants necessary to demonstrate a no-mismatch graft survival advant age! at 2 years. Results, Part I: Although no actual cadaveric no-mismatch transplant was pe rformed, 12-17% of patients could have received no-mismatch allografts had sharing been in place, using various donor acceptance criteria. The impact on waiting time was variable. Part II: Accepting a 15% rate of no mismatch cases and a survival advantage of 10% at 2 years, 793 transplants would be required to prove an advantage to HLA matching at P<0.05, If the graft surv ival advantage were 20% at 2 years, the time to show significance would be approximately 5 years. Using early acute rejection as an endpoint could req uire fewer transplants (93), and only a few years to complete the study. Conclusions. National sharing of cadaveric isolated intestinal allografts i s feasible. Median waits would not be significantly increased. The time nec essary to prove graft survival advantage would be considerable, but a diffe rence in the rate of acute rejection could be seen within 2 years. Addition ally, a national sharing arrangement might improve the overall outcome of i solated intestinal transplantation.