Association of agonal phase duration with heart utilization and post-transplant outcomes in donation after circulatory death heart transplantation

Background: This study evaluates the impact of the agonal phase and related hemodynamic measures on post-transplant outcomes and heart utilization in donation after circulatory death (DCD) heart transplantation.

Methods: United Network for Organ Sharing registry was queried to analyze adult recipients who underwent isolated DCD heart transplantation between January 1, 2019 and September 30, 2023. The recipients were stratified into 2 groups based on donor agonal period: <30 and ≥30 minutes. The primary outcome was 90-day post-transplant survival. Propensity score-matching was performed. Sub-analysis was performed to evaluate the association of agonal period with donor heart utilization. Additionally, the associations between different hemodynamic thresholds used to indicate onset of warm ischemia during the agonal phase with 90-day mortality were compared.

Results: Eight hundred and eighty nine recipients were included, with 179 (20.1%) receiving hearts from donors with an agonal period of ≥30 minutes. Ninety-day survival (88.1% vs. 95.6%, p < 0.001) was significantly lower among the recipients of donors with an agonal period of ≥30 minutes. The lower 90-day survival persisted in a propensity score-matched comparison. Furthermore, longer agonal periods were associated with reduced donor heart utilization. Lastly, a time interval from a systolic blood pressure of 80 ± 5mmHg to death exhibited significantly higher association with 90-day mortality than a time interval from a systemic oxygen saturation 80 ± 5% to death.

Conclusions: Utilizing DCD donor hearts with agonal periods ≥30 minutes is associated with reduced post-transplant survival and decreased donor heart utilization. When assessing the onset of warm ischemia during the agonal phase, hypotension may serve as a more accurate indicator of myocardial ischemia and provide improved post-transplant prognostic insight than hypoxia.