Effects of Functional Warm Ischemia Time on Posttransplant Outcomes in Donation After Circulatory Death Heart Transplantation Using Direct Procurement and Perfusion

BACKGROUND: This study evaluates the impact of functional warm ischemia time (FWIT) on outcomes following isolated donation after circulatory death (DCD) heart transplantation using direct procurement and perfusion (DPP). METHODS: The United Network for Organ Sharing registry was queried for adult recipients of isolated DCD heart transplants performed using DPP from January 1, 2019, to December 31, 2023. Recipients were stratified by donor FWIT: <30 versus ≥30 min. The primary outcome was 1-y posttransplant survival. Risk adjustment was performed using propensity score-matching and multivariable Cox regression. Subgroup analyses examined the effects of recipient age and total graft preservation time. RESULTS: A total of 681 recipients were included, with 155 (22.8%) receiving hearts from DCD donors with FWIT ≥30 min. The recipients with FWIT ≥30 min had significantly lower 1-y posttransplant survival than those with FWIT <30 min (86.4% versus 92.7%; P = 0.011). This survival difference remained significant after propensity score-matching and multivariable adjustment. When treating FWIT as a continuous variable, longer FWIT was associated with increased odds of 1-y mortality. Subanalyses demonstrated that recipient age ≤50 y and graft preservation time ≤6 h improved 1-y survival among the recipients with FWIT ≥30 min, comparable to those with FWIT <30 min. CONCLUSIONS: Longer FWIT in DCD heart transplantation using DPP is associated with reduced 1-y posttransplant survival. However, transplanting these hearts in younger recipients or with shorter preservation times may mitigate these adverse effects, achieving outcomes comparable to those with shorter FWIT. Therefore, careful recipient selection and risk stratification are essential to optimize outcomes when using donor hearts with extended FWIT.