Heart transplant outcomes with use of pediatric donors for adult recipients: Insights from the International PGD Consortium.

PURPOSE: Donor age is a critical determinant of severe primary graft dysfunction (PGD) after heart transplant (HT), yet the safety and efficacy of using younger donor hearts for adult recipients remains incompletely characterized. Given ongoing organ shortages, an understanding of the relationship between pediatric donor age and post-transplant outcomes is essential to inform donor selection and optimize utilization.

METHODS

The International Consortium on PGD database retrospectively enrolled adult HT recipients and their donors from 14 centers across the United States, Canada, and Europe. In the present analysis, all adult recipients (≥18 years old) who underwent HT between 2010 and 2023 were included. The independent association of donor age with post-HT outcomes, including severe PGD and 1-year mortality, was evaluated using multivariable analysis accounting for predicted heart mass (PHM) ratio,recipient-donor age difference, geographical region, and recipient-donor sex match. Nonlinear associations of continuous covariates were assessed using restricted cubic splines.

RESULTS

Among 3787 HT recipients, pediatric donors <15 years accounted for 1.3%, while 5.0% were 15-18 years old. Recipients of pediatric donor hearts were slightly younger (donor age <15 years: 48±14; donor age 15-18: 51.3±14.1; donor age >18: 53.7±12.2 years), and were more likely to be of female sex (53.1% vs. 26.2% vs. 25.2%). While 7.64% of donors in North American centers were below the age of 18 years and 1.79% below the age of 15 years, these proportions were 3.6% and 0.25% in European centers. After multivariable analysis, donor age was independently associated with severe PGD (P = 0.006), with pediatric donor age conferring improved outcomes in spline analysis, but not 1-year mortality (P=0.156). Recipient-donor age difference showed a non-significant trend toward increased PGD risk at extreme age mismatches (P=0.056) and was not associated with mortality (P=0.88).

CONCLUSIONS

Donor age demonstrates an independent association with severe PGD following adult heart transplantation. Pediatric donor age confers progressively lower risk, with equivalent survival at 1 year. These findings suggest that carefully selected younger donor hearts can be used safely and support consideration of donor age as a continuous risk factor, rather than reliance on arbitrary thresholds in clinical decision-making.