Successful Heart Transplantation After 24 h of Ex‐Situ Normothermic Perfusion Using ECMO Technology in an Animal Model: A Proof‐of‐Concept Study

Background Ex situ heart perfusion (ESHP) allows longer preservation times and provides the opportunity to assess cardiac function. The goal of our study was to evaluate the impact of the treatment of beating heart in normothermic ESHP based on ECMO technology on post‐transplant graft function in an animal model. Methods Ten healthy male adult domestic pigs weighting 90–95 kg were selected to donate hearts n = 5 donors for prolonged (24 h) normothermic ESHP based on ECMO technology and n = 5 recipients. Perfusion system consisted of ECMO oxygenator, centrifugal pump, tubing and integrated ultrafiltration device. Baseline echocardiographic and hemodynamic parameters, along with coronary angiography, were evaluated before each heart explantation, during ex situ perfusion, and prior to transplantation. Following 24 h of ESHP, orthotopic heart transplants were performed utilizing the bicaval technique during 4 posttransplant hours. Outcomes of interest were the change in lactate, ischemic time, perfusion time, hemodynamic evaluation of the heart, and morphologic changes after heart transplantation. Results Heart harvesting, continuous ESHP for 24 h followed by orthotopic transplantation was performed. The mean duration was 1440 ± 80 min. Echocardiographic evaluation of the heart during ex vivo perfusion revealed a normal trend of Tissue Doppler Imaging (TDI) parameters. The mean left ventricular ejection fraction after heart transplantation was 48% (±0.7), cardiac output and cardiac index after transplantation was 6.0 L/min (±0.7) and 3.1 (±0.2) l/min/m 2 , respectively. For over 4 h post‐transplant, there was no evidence of graft dysfunction. Conclusions This study demonstrates that hearts without prior DBD/DCD exposure or cold ischemic injury are able to recover and maintain functional viability following 24 h of ex‐situ heart perfusion.