Oversized donor heart transplantation-clinical experience with an underestimated problem

Heart transplantation is the definitive treatment for end-stage heart failure. With respect to donor-recipient size matching, the problems with undersized heart transplantation have been widely discussed, but there is a paucity of information on oversized transplants due to the presumed advantage of large hearts. We intend to share our center's experience with oversized heart transplantation and its associated problems which would help to expand the knowledge on oversized cardiac allografts.

Patients who underwent isolated heart transplantation at our hospital between March 1, 2008, and March 1, 2020, were included. For adults, a donor-recipient predicted heart mass percentage difference exceeding 30% and for children, a donor-recipient weight ratio < 0.8 and > 2.0 was considered a mismatch. We collected data from the in-patient medical records and analyzed the in-hospital outcomes and survival post-transplant among various other parameters.

Out of the 43 patients included in this study, 32 (74.4%) patients received a matched heart and 11 (25.6%) patients received oversized hearts. None of the patients received an undersized heart. The in-hospital mortality rate of oversized transplants was 18.2% whereas that of matched transplants was 9.4% (p = 0.432). The post-operative characteristics and 1-year survival were comparable between the groups. We encountered problems specific to oversizing in 5 of the 11 patients (45.4%) which are discussed.

With the liberalization of donor criteria to overcome organ shortage, oversized heart transplantation poses certain unique challenges, which when efficiently managed offers acceptable outcomes.