Ex-situ oxygenated hypothermic machine perfusion in donation after circulatory death heart transplantation following either direct procurement or in-situ normothermic regional perfusion

Background: Heart transplantation in donation after circulatory death (DCD) relies on warm perfusion using either in situ normothermic regional perfusion (NRP) or ex situ normothermic machine perfusion. In this study, we explore an alternative: oxygenated hypothermic machine perfusion (HMP) using a novel clinically applicable perfusion system, which is compared to NRP with static cold storage (SCS). Methods: In a porcine model, a DCD setting was simulated, followed by either (1) NRP and SCS (2) NRP and HMP with the XVIVO Heart preservation system or (3) direct procurement (DPP) and HMP. After preservation, heart transplantation (HTX) was performed. After weaning from cardiopulmonary bypass (CPB), biventricular function was assessed by admittance and Swan-Ganz catheters. Results: Only transplanted hearts in the HMP groups showed significantly increased biventricular contractility (end-systole elastance) 2 hour post-CPB (left ventricle absolute change: NRP HMP: +1.8 ± 0.56, p = 0.047, DPP HMP: +1.5 ± 0.43, p = 0.045 and NRP SCS: +0.97 ± 0.47 mmHg/ml, p = 0.21; right ventricle absolute change: NRP HMP: +0.50 ± 0.12, p = 0.025, DPP HMP: +0.82 ± 0.23, p = 0.039 and NRP SCS: +0.28 ± 0.26, p = 0.52) while receiving significantly less dobutamine to maintain a cardiac output >4l/min compared to SCS. Diastolic function was preserved in all groups. Post-HTX, both HMP groups showed significantly less increments in plasma troponin T compared to SCS. Conclusion: In DCD HTX, increased biventricular contractility post-HTX was only observed in hearts preserved with HMP. In addition, the need for inotropic support and signs of myocardial damage were lower in the HMP groups. DCD HTX can be successfully performed using DPP followed by preservation with HMP in a preclinical setting.