Prolongation of long-term kidney graft survival by a simultaneous liver transplant:: The liver does it, and the heart does it too

Background. Whereas some authors reported that kidney transplants were protected from rejection by simultaneous liver grafts, other authors failed to obtain evidence for a kidney graft-protective role for the liver. Methods. The survival rate of 383 kidney grafts in recipients of combined kidney-liver transplants performed between 1985 and 2000 and reported to the international Collaborative Transplant Study (CTS) was analyzed and compared retrospectively with that of a matched group of control patients who were transplanted with kidneys only. In addition, 105 combined kidney-heart transplants performed during the same time period were analyzed. Results. At I year, the survival rate of kidney grafts in recipients. of kidney-liver transplants was significantly lower than that in kidney. only recipients (P < 0.0001). Subsequently, however, kidneys in kidney-liver recipients fared much better so that the success rates were virtually identical after 8 years of follow-up (62.1 +/- 3.5% vs. 61.9 +/- 2.3%, P = ns). Half-life times after the first posttransplant year were 27.6 and 14.5 years for combined or single kidney grafts, respectively, and the projected 20-year graft survival rates were 46% and 35%, respectively. The 8-year survival rate of kidney grafts in recipients of combined kidney-heart recipients was 63.5 +/- 6.2%, the associated half-life time 31.6 years, and the projected 20-year graft survival rate 49%. Conclusions. The long-term kidney graft survival rate is higher in recipients of combined kidney-liver transplants than in recipients of kidney grafts only. Because the success rate is equally high in recipients of combined kidney-heart transplants, it is necessary to reexamine the hypothesis that the liver possesses a unique capacity of protecting a simultaneous kidney graft from rejection.