Size compatibility in pediatric heart transplantation: impact on outcomes

Donor-recipient size mismatch in pediatric heart transplantation remains a clinically important and frequently debated issue, with significant implications for donor utilization and outcomes. In this context, the authors Ganduboina et al. provide a thoughtful analysis of the impact of size mismatch, stratified into graded categories and further delineated into undersizing and oversizing. Oversizing, which is considerably more common in contemporary practice, was not associated with adverse outcomes across short-, mid-, or long-term survival, reinforcing the growing acceptance of liberal size-matching strategies. In contrast, undersizing was associated with reduced mid-term survival; however, this relationship did not persist after adjustment for confounding variables, suggesting that recipient and perioperative factors may play a more dominant role than size mismatch alone. These observations align with evolving clinical practice, where oversized grafts are often preferentially used in higher-risk recipients to provide physiological reserve. At the same time, the study underscores the need to interpret size mismatch within a broader clinical context, rather than as an isolated determinant of outcome. Collectively, these findings support a more flexible, individualized approach to donor selection while highlighting areas for future refinement.