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Effect of cold ischemic time and HLA matching in kidneys coming from "young" and "old" donors: do not leave for tomorrow what you can do tonight.

BACKGROUND
Kidneys from older donors are likely to have a lower nephron mass. Nevertheless they constitute a valuable source of kidney allografts. Long cold ischemic time (CIT), with or without delayed graft function (DGF), has been associated with reduced graft survival. The aim of this study was to review the experience of a single UK center to assess the interaction of cold storage time, donor age, organ exchange, and HLA-DR mismatching on short- and long-term survival.


METHODS
We analyzed 788 first cadaver kidney transplants that were performed in our center from 1990 to 1997 and had complete data available. A donor age of 55 years was the cutoff age for "old" and "young" donor kidneys. The primary outcome measured was graft failure from any cause.


RESULTS
There were 132 grafts from donors 55 years or older (16.7%), with 76.8% of the kidneys implanted after >20 hr of CIT. Kidney grafts from donors older than 55 years had worse graft survival than grafts from donors younger than 55 (87% vs. 78% at 1 year and 80% vs. 58% at 5 years after transplant, P=0.0001). A CIT of >20 hr significantly reduced graft survival (91% vs.74.3% at 5 years after transplant, P=0.0002) in the young donor group and was associated with an overall graft survival in the old donor group of 57.5% at 5 years. In the same group, ignoring the HLA-DR mismatching to achieve shorter CIT, the predicted initial cost on graft survival at 1 year would have been 3.7% but would have increased to 9% 5 years after transplant. For young donors a CIT of >20 hr had a cost of approximately 18% at 5-year graft survival, far higher than a single DR mismatch. Occurrence of DGF decreased survival in both short (P=0.001) and long (P=0.00001) CIT groups.


CONCLUSION
Forming local alliances (common recipient lists) and minimizing delays within the hospital might reduce CIT and DGF while achieving excellent HLA matching. This should improve significantly the outcome of both old and young donor kidney grafts.