[Is there a safe cold ischemia time interval for the renal graft?]

Abstract

Objective: It is aimed to characterize the true relationship of the cold ischemia time (CIT) with graft survival and with the principal post-transplantation events.

Material and methods: We analyzed 378 kidney transplants, studying the relationship of the CIT with graft survival using a univariate analysis according to the COX model and seeking the optimum cutoff according to the Kaplan-Meier method and log-rank test. The relationship between CIT and the principal events of the post-transplant was studied using the binary logistic regression.

Results: The mean follow-up of all the group was 77.8 months (± 51 SD) and the mean CIT was 14.8 hours (± 5.1 SD). The univariate analysis revealed that the CIT was not related with the graft survival as a continuous variable (OR=1.04; 95% CI: 0.9-1.08; p>0.05). On establishing the cutoff at 18 hours, we found differences in the actuarial survival. Survival at 5 years was 91% with CIT < 18 h versus 84% with CIT >18 h. Each hour of cold ischemia increased risk of delay in the graft function by 10% (OR=1.1; 95% CI: 1.05-1.15; p<0.001) and also conditioned a greater incidence of acute rejection (41.5% vs. 55.3%; p=0.02) and less time to the first rejection episode (72.6 days±137 vs. 272.2 days±614.8; p=0.023) after 18 hours. The CIT did not seem to be related (p<0.05) with the rest of the post-transplantation events, such as surgical complications or hospital admissions.

Conclusions: In our experience, cold ischemia under 18 hours does not seem to negatively affect graft survival.