ABSTRACT
BACKGROUND: Donation after circulatory determination of death (DCDD) involves variable definitions of death among hospitals, and DCDD hearts are not generally considered for transplantation. The definition can affect ischemic times, and machine perfusion preservation appears promising for recovery of DCDD hearts. The purpose of the current study was to investigate the agonal phase of DCDD donors and evaluate retrograde perfusion preservation of DCDD donor hearts in a large animal model of cardiac transplantation. METHODS: Ten canines were anesthetized and then disconnected from mechanical ventilation. Time to loss of pulse (systolic blood pressure <50 mm Hg), loss of pressure, and asystole or fibrillation were recorded. Five minutes after asystole, hearts were exposed and arrested with 1 L of University of Wisconsin Machine Perfusion Solution. Eight hearts were cold preserved for 4 hours by retrograde machine perfusion or static storage (n = 4/group), then reimplanted and reperfused for 6 hours. The preload recruitable stroke work was used to measure myocardial function. RESULTS: The agonal phase was similar between groups. Loss of pulse and pressure were consistent between animals (7.9 ± 0.5 minutes [range, 5 to 11 minutes], 10.2 ± 0.4 minutes [range, 9 to 13 minutes], respectively). Electrical silence was variable at 26.9 ± 3.8 minutes (range, 11 to 43 minutes). All perfused hearts separated and remained off cardiopulmonary bypass. Three of four static hearts initially separated from cardiopulmonary bypass, but two returned by the end of the reperfusion period. The preload recruitable stroke work was significantly higher in perfused hearts. CONCLUSIONS: Protocols for DCDD have implications on ischemic times of donor hearts. Machine perfusion preservation can recover DCDD hearts more consistently than static storage.
