The International Thoracic Organ Transplant Registry of the International Society for Heart and Lung Transplantation: 2026 Adult Heart Transplantation: A contemporary analysis of trends and outcomes by recipient sex.

BACKGROUND

Sex-based differences may affect recipient profiles, donor selection, support, and outcomes after heart transplantation. Using the International Society for Heart and Lung Transplantation Registry, we evaluated trends by recipient sex.

METHODS

Adults undergoing primary heart-alone transplantation from 2005 through 2023 were analyzed. Recipient and donor characteristics, support strategies, donor utilization, 1-year survival, and 5-year conditional survival among 1-year survivors were compared by recipient sex. Multivariable Cox models were adjusted for clinical covariates and predicted heart mass difference.

RESULTS

Among 50,614 recipients, 13,248 (26.2%) were female. Compared with male recipients, female recipients were younger and more often had nonischemic cardiomyopathy, hypertrophic cardiomyopathy, or congenital heart disease. They also had higher rates of allosensitization, were less often bridged with durable left ventricular assist devices, and were more often transplanted without mechanical circulatory support. Expanded donor use increased in both sexes, while durable left ventricular assist device use declined and temporary support increased. One-year survival improved over time and was similar by recipient sex within eras. After adjustment, most donor-recipient sex-pairing associations were attenuated. Female donor-female recipient transplantation remained associated with higher 1-year mortality versus male donor-male recipient transplantation (hazard ratio, 1.12; 95% confidence interval, 1.02-1.22), and male donor-female recipient transplantation was associated with higher 5-year conditional mortality (hazard ratio, 1.17; 95% confidence interval, 1.04-1.31).

CONCLUSIONS

Recipient sex is associated with distinct case mix, support strategies, donor utilization, and outcome patterns. These findings support matching strategies that incorporate size, immunologic, and clinical risk.