Optimal Donor Allograft Function: The Search for the Lowest Acceptable Donor Left Ventricular Ejection Fraction in Pediatric Heart Transplantation

Abstract

Background. The availability of heart donors is limited by organ shortage. Due to concerns of reduced survival, donors with depressed left ventricular ejection fraction (LVEF <50%) have been cautiously used in pediatric heart transplantation. One strategy to expand the donor pool is to re-evaluate whether lower donor LVEF may be acceptable for transplantation. Methods. We performed a multicenter retrospective cohort study of patients <18 y receiving heart transplants from April 2007 to September 2021 using the United Network of Organ Sharing dataset. We excluded retransplants and multiorgan transplants. Cut-point analyses of LVEF was performed and Kaplan–Meier method was used to compare 1-y survival for new cut-points and the standard (LVEF >50%). Results. The analytic sample consisted of 5255 patients. Recipients receiving hearts with lower LVEFs were more likely to be on ventilator and extracorporeal membrane oxygenation support. Recipients did not differ in waitlist times or transplant status. Cut-point analysis identified LVEF 45% as a potentially new cutoff. One-year survival of recipients of donors with LVEF ≥45% (92.1%; 95% confidence interval [CI], 91.3%-92.8%) was similar to that of LVEF >50% (92.1%; CI, 91.4%-92.9%). Survival for the LVEF 45%–49% (88.8%; CI, 72.9%-95.7%) cohort was slightly lower than the ≥50% cohort, albeit nonsignificant. Conclusions. One-year survival among pediatric heart transplants using a donor heart LVEF threshold of 45% or 40% was similar to a threshold of 50%. However, the finding is based on a small number of patients with LVEF <50%, and future larger prospective studies are warranted to confirm the findings of this study before a lower LVEF threshold is considered.