Impact of Predicted Heart Mass-Based Donor-Recipient Size Matching on Transplant Outcomes

Abstract

Background: Currently, guidelines for appropriate donor sizing in recipients mostly focuses on donor-recipient body weight matching. The purpose is to retrospectively determine the impact of predicted heart mass (pHM)-based size matching on heart transplant (HT) outcomes.

Methods: According to our institutional registry, 512 consecutive adult patients underwent HT between January 2000 and August 2020. For each patient, pHM and donor-recipient pHM ratio were calculated. Patients were partitioned into quintiles in terms of pHM ratio: undersizing 2, undersizing 1, reference, oversizing 1, and oversizing 2, with mean pHM donor-recipient ratio of 0.81, 0.96, 1.04, 1.12, and 1.28, respectively. Severe early graft failure and 30-day, 90-day, 1-year, and 10-year mortality were analyzed as outcomes.

Results: Recipients of the most oversized group were mostly female (P < .001), had higher preoperative pulmonary vascular resistance (P = .009), had higher rate of mechanical circulatory support (P < .05), and showed a lower United Network for Organ Sharing score (P = .041); the respective donors were younger and more frequently male (P = .001). Ischemic time was similar in all groups (P = .358). Pulmonary vascular resistance (P = .023; odds ratio [OR], 2.38), preoperative mechanical circulatory support (P = .05; OR, 3.06), and United Network for Organ Sharing score (P = .033; OR, 1.76) were identified as risk factors for early mortality. Donor-recipient pHM ratio did not impact early graft failure (P = .871) and early mortality (P = .526). Survival analysis after adjustment for pHM ratio subgroups did not show any difference in outcomes.

Conclusions: A wide range of pHM ratios seems to be safe. A careful allocation of organs, by considering a pHM ratio mismatch, may balance rescue preoperative clinical profiles and preserve HT outcomes.