Introduction
Orthotopic heart transplantation (OHT) remains the gold standard treatment for advanced stage heart failure1. When selecting an appropriate donor for each intended recipient, it is paramount that donor-to-recipient sizing is within acceptable standards in order to meet the cardiac output demands of its recipient2,3. As a donor heart under consideration typically cannot be directly inspected prior to the deployment of a harvesting team, a number of different metrics have been utilized in clinical practice as a quick tool for sizing. These metrics include height, weight, and/or body mass index (BMI) ratios, and even predicted heart mass (pHM) calculations2–6. For weight sizing, some experts have advocated to finding a donor-recipient match pair with ≤ 30% weight discrepancy7, but others advocate for a more conservative ≤ 20% discrepancy8,9. However, the correlations with some of these measurements to actual heart size have come into question.
In addition to choosing a donor heart of optimal size, considerations must also be taken into donor and recipient gender. Prior study has suggested that female to male (FtoM) donation may be associated with increased risk of posttransplant mortality10–13. A possible explanation is that a donor female graft may be more likely to be under-sized when paired with a male recipient, resulting in a cardiac supply-demand mismatch in the posttransplant period. As there is no definitive consensus with regards to how donor-recipient heart sizing should be conducted, we sought to analyze the distributions of sizing in the FtoM OHT population using available sizing metrics. We aimed to investigate the impacts of these metrics on posttransplant survival in this potentially higher-risk transplant cohort.