Do Prolonged Donor Warm Ischemic Times Correlate With Kidney Transplant Outcomes? The Largest Study of Donation After Circulatory Death Donors in the United States.

BACKGROUND

Donation after circulatory death (DCD) kidneys are discarded because of long donor warm ischemic times (WIT), despite an unclear association between WIT and outcomes.

METHODS

Using Organ Procurement and Transplantation Network data of adult DCD kidney recipients from 2015 to 2022, we examined donor WIT, using total WIT and 6 definitions of functional WIT (agonal, asystolic, and time beyond derangements in blood pressure or oxygen saturation). We fit logistic and Cox regression models for primary nonfunction (PNF) and 1-y death-censored graft failure (DCGF), respectively, treating WIT linearly and with a spline at the 87.5th percentile.

RESULTS

Among 13 673 donors and 24 271 recipients, the median total WIT was 26 min and 1474 transplants were performed from donors with >60 min of total WIT. PNF incidence was 2.6%; 1-y DCGF was 3.8 events per 100 patient-years. In both models, asystolic time was associated with increased hazard of 1-y DCGF (adjusted hazard ratio per 5 min with time linear, 1.12; 95% confidence interval [CI], 1.03-1.22; adjusted hazard ratio per 1 min beyond 12 min, 1.07; 95% CI, 1.02-1.13) and increased odds of PNF (adjusted odds ratio per 5 min with time linear, 1.18; 95% CI, 1.07-1.30; adjusted odds ratio per 1 min beyond 12 min, 1.08; 95% CI, 1.02-1.13). Other measures of donor WIT were not associated with DCGF or PNF. Holding other covariates constant, the absolute risk of 1-y DCGF increased by 0.9% when asystolic time increased from 5 to 25 min in the linear model.

CONCLUSIONS

Donors with prolonged total and functional WITs, apart from asystolic time, show no association with 1-y DCGF and PNF. We advocate using these kidneys to expand the donor pool.