Introduction of machine perfusion of donor hearts in a single center in Germany

Introduction: Organ shortage, subsequent use of extended donor criteria organs and high-risk recipients needing redo-surgery are increasing the complexity of heart transplantation. Donor organ machine perfusion (MP) is an emerging technology allowing reduction of ischemia time as well as standardized evaluation of the organ. The aim of this study was to review the introduction of MP and analyze the results of heart transplantation after MP in our center. Methods: In a retrospective single-center study, data from a prospectively collected database were analysed. From July 2018 to August 2021, fourteen hearts were retrieved and perfused using the Organ Care System (OCS), 12 hearts were transplanted. Criteria to use the OCS were based on donor/recipient characteristics. Primary objective was 30-day survival, secondary objectives were major cardiac adverse events, graft function, rejection episodes as well as overall survival in the follow-up and assessment of MP technical reliability. Results: All patients survived the procedure and the postoperative 30-day interval. No MP related complications were noted. Graft ejection fraction beyond 14 days was ≥ 50% in all cases. Endomyocardial biopsy showed excellent results with no or mild rejection. Two donor hearts were rejected after OCS perfusion and evaluation. Conclusion: Ex vivo normothermic MP during organ procurement is a safe and promising technique to expand the donor pool. Reduction of cold ischemic time while providing additional donor heart assessment and reconditioning options increased the number of acceptable donor hearts. Additional clinical trials are necessary to develop guidelines regarding the application of MP.