Time to Death and Donation After Circulatory Death Kidney Transplant Outcomes: Opportunities for Improved Utilization...

Concerns persist that prolonged time to death (TTD) following withdrawal of life-sustaining treatment may impair organ quality. Although previous European studies have demonstrated that prolonged TTD does not impact post-transplant kidney graft survival, it remains unclear whether these findings apply to the US donor pool.

We used OPTN data on adult DCD single-kidney transplants (2010-2023). Multiple imputation was used for missing data. Multivariable regression models, with restricted cubic splines for non-linear modelling, were used to evaluate the impact of donor TTD on kidney transplant outcomes.

Median donor TTD was 14 min (IQR, 10-21 min). Donor TTD was not associated with recipient graft survival (p = 0.469), mortality (p = 0.528) or 1-year eGFR (p = 0.393). These findings were consistent regardless of normothermic regional perfusion use (NRP cohort: n = 1227; non-NRP cohort: n = 35 328), and within the large ex-situ hypothermic machine perfusion cohort (HMP- cohort: n = 22 218). Only 4.1% of transplanted DCD kidneys were from donors with TTD of over 60 min, and just 0.1% exceeded 120 min.

Increasing donor TTD was not associated with worse post-kidney-transplant outcomes within this cohort predominantly comprising donors with TTD 0-60 min. In contrast to this US setting, a previous UK study reported that a higher proportion of transplanted DCD kidneys were from prolonged TTD donors (12.3% from donors TTD >60 min; 4.2% from >120 min). This highlights an opportunity to safely expand the US DCD donor pool, especially in the era of machine perfusion where viability assessment may provide an additional safeguard.