Introduction of Machine Perfusion in Donor Hearts

Abstract

Purpose Heart Transplantation (HTX) is an established therapy for endstage Heart Failure with excellent long term results. However, shortage of donor organs leads to increased use of extended criteria organs and rising numbers of high risk recipients on the high-urgency list and on mechanical circulatory support (MCS). Donor organ machine perfusion (MP) allows continuous warm perfusion of the beating heart, thus reducing time of ischemia as well as allowing for standardized evaluation. AIM: analyze outcome of HTX using donor heart MP. Methods In a retrospective single-center study, data from a prospectively collected database were analyzed. From July 2018 to September 2020, eleven hearts were retrieved and perfused using the Organ Care System (OCS), 9 hearts were transplanted. Criteria to use the OCS were 1) estimated ischemic time > 4 hours for any reason, 2) inotropes > 0.25 µg/kg/min, 3) LV-EF Results All patients survived the procedure and the 30-day interval [time since HTX 8-799 d]. No MP related complications were noted. One patient died after 233 days due to sepsis. 4 patients were on temporary ECLS support in the early postoperative period (6-12d) due to initial right ventricular dysfunction. Graft ejection fraction beyond 14 days was ≥ 50% in all cases. Endomyocardial biopsies showed no rejection or mild rejection 1R in two cases (21d and 3 months surveillance biopsy). Two donor hearts were rejected after OCS perfusion 1) because of previously unknown coronary artery disease (angiography on OCS) and 2) due to underestimated aortic valve insufficiency and severe septum hypertrophy. 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 may increase the number of acceptable donor hearts and improve results. Future clinical trials will bring further evidence, clear guidelines regarding application of MP have to be developed.