Early Administration of Crystalloid Cardioplegia after Circulatory Death in a Porcine Model of Cardiac Resuscitation

Abstract

Transplantation of hearts donated after circulatory death (DCD) remains challenging due to the risk myocardial injuries. These hearts are exposed to hypoxia and prolonged warm ischemic time (WIT). We hypothesize that administration of cardioplegia (CPG) after extended WIT could make DCD hearts suitable for transplantation without severe myocardial injury. A hypoxic cardiac arrest was induced in twelve piglets (40 kg). Since peripheral cannulation could not be considered, a normothermic regional perfusion (NRP) was established between the right atrium and the aortic arch, 5 min. after mechanical asystole. In the CPG group (n=6), a crystalloid solution (40 mL/kg, Celsior, IGL, Lyon, France) was administered after 15 min. of WIT, while no preservation solution was administrated in the control group (n=6). The aortic clamp was released after 35 min. and NRP withdrawal was attempted 60 min. after cardiac reperfusion. Pressure-volume loops were performed before and after cardiac resuscitation. Early ischemic changes were detected on Masson's trichrome staining and incorporated to a composite score. Agonal phase was 14 min. in the CPG group (9.5-14) vs. 12 min. (11-13) (P=1.0). Three (50%) piglets could be weaned from NRP in the CPG group, vs. 1 (16.7%) in the CTL group (P=0.55). Troponin I was not different between groups (53 vs. 49 µg/L, P=0.73). All resuscitated hearts had biventricular function impairment with marked decline in left ventricular end-systolic elastance. Left ventricular ischemic changes were less severe in CPG group (P=0.034), while multifocal myocardial injury of the right ventricle was observed in both groups (Figure 1). Early administration of crystalloid cardioplegia was associated with a 50% rate of heart resuscitation in our porcine model. The viability of DCD hearts after prolonged WIT was limited by right ventricular severe injury.