Reduction in Cold Ischemia Time of Renal Allografts in the United States Over the Last Decade

A reduction in cold ischemia time (CIT) can be associated with better renal allograft outcomes. However, few published surveys of CIT of deceased donor kidneys transplanted in the United States are available. We therefore surveyed the CIT using the United Network for Organ Sharing data of the last decade. A reduction in CIT was observed during the 10-year period with an overall reduction of 4.8 hour (n = 75,072; mean ± SD, 24.4 ± 10.9 hour in 1990 vs 19.6 ± 8.4 hour in 2000, P < .001) with fewer kidneys being cold-stored over 30 hour in the second half (13% in 1996 to 2000 vs 25% in 1990 to 1995, P < .001). Although the overall rates of delayed graft function were not different between the two periods (24% in 1990 to 1995 vs 25% in 1996 to 2000), possibly due to increased use of kidneys from extended criteria donors and donors after cardiac death and the persistence of CIT over 20 hours in the second half, the 6-month posttransplant graft function (serum creatinine: 1.63 ± 0.01 mg/dL in 1996 to 2000 vs 1.75 ± 0.01 mg/dL in 1990 to 1995; P < .001) and the 3-year graft survival (80% in 1996 to 2000 vs 72% in 1990 to 1995; P < .001) were better. Thus, our analysis demonstrates an overall reduction in mean CIT over the last decade, with fewer kidneys being cold-stored over 30 hours in the latter half. This raises the possibility that besides the influence of improved immunosuppression, reduction in CIT might have also contributed to the recently observed improvements in graft outcomes.