Impact of coronary hypoperfusion during agonal phase on outcomes following donation after circulatory death heart transplantation

BACKGROUND: This study evaluates the impact of low diastolic blood pressure and resultant coronary hypoperfusion during the agonal phase on outcomes following donation after circulatory death (DCD) heart transplantation. METHODS: The United Network for Organ Sharing (UNOS) registry was queried to analyze adult recipients of isolated DCD heart transplants between 1/1/2019-9/30/2023. Recipients were stratified based on the proportion of the agonal phase with coronary hypoperfusion, defined as diastolic blood pressure <40 mmHg. Using threshold regression, coronary hypoperfusion was classified as extensive (>20% of the agonal phase) or limited (≤20% of the agonal phase). The primary outcome was 1-year post-transplant survival. Risk adjustment was performed using multivariable Cox regression and 1:1 propensity score-matching. RESULTS: Among 696 recipients of DCD hearts, 105 (15.1%) received hearts with limited coronary hypoperfusion during the agonal phase. The extensive coronary hypoperfusion group had a nominally shorter median agonal phase duration than the limited coronary hypoperfusion group (19 vs 21 min, p = 0.17). The recipients with extensive coronary hypoperfusion had significantly reduced 1-year post-transplant survival than those with limited coronary hypoperfusion (91.1% vs 97.1%, p = 0.039). These findings persisted in both multivariable Cox regression and propensity score-matched analyses. CONCLUSION: Extensive coronary hypoperfusion during the agonal phase in DCD donor hearts is associated with reduced post-transplant survival, even when the total agonal period is short. These findings suggest that the impact of the agonal phase is determined not only by its duration but also by the extent of allograft malperfusion, highlighting the need to reconsider rigid time-based criteria for DCD heart acceptance and utilization.