Old donors for kidney transplantation: how old?

The widening gap between transplant demand and supply has prompted the expansion of selection criteria for kidney donation to increase the available donor pool. Using kidneys from older donors has increased transplant activity, but has also resulted in reduced graft survival, possibly as a consequence of the imbalance between the number of viable nephrons supplied and the metabolic demand of the recipient. To fill this imbalance and improve graft outcomes, the transplant of 2 older kidneys in the same recipient has been proposed. This procedure, however, does not always confer the same benefit of single transplants from young donors. To optimize allocation of these organs, a panel of pathologists defined a scoring system of pretransplant graft biopsies to help guide the decision between single versus dual kidney transplantation. The survival of kidneys obtained from donors older than 60 years and allocated to single or dual transplantation on the basis of this pretransplant biopsy score was similar to that of single grafts from younger donors and substantially better than that of single grafts from older donors not evaluated histologically before grafting. This strategy has provided excellent outcomes even when kidneys from donors older than 70 years have been used. Thus, biopsy-based allocation algorithm of older grafts may allow extending selection criteria of donors to increase the number of available transplants without increasing the risk of premature graft failure.