Outcomes of teenage donor hearts transplanted into adult heart transplant recipients: A United Network for Organ Sharing analysis.

Abstract

The safety of using teenage donor hearts for adult recipients is unclear. Moreover, the appropriateness of predicted heart mass ratio as a size metric for teenage donors is unknown. We used the United Network for Organ Sharing database to perform a retrospective analysis of heart-only adult transplant recipients (>18 years). Donors were stratified as teenage (age 12-17 years, N = 5772) or adult donors (age ≥18 years, N = 57,922). Predicted heart mass ratio was computed using age, sex, height, and weight. Predicted heart mass ratio was categorized into septiles, after excluding outliers 2 Z-scores above or below the mean. The mean ages of teenage and adult donors were 16 ± 1.4 years and 34 ± 11 years, respectively (P < .001). Average predicted heart mass ratio was higher for recipients of teenage (1.29 ± 0.15) compared with adult (1.12 ± 0.14) donors (P < .001). Cox proportional hazards model adjusting for confounders showed increased survival among recipients of teenage donor hearts compared with those with adult donors at 1 year (hazard ratio, 0.96, 95% CI, 0.75-0.99) and 5 years (hazard ratio, 0.84, 95% CI, 0.76-0.93). Adjusted analysis within the teenage cohort found that predicted heart mass ratio septiles were not associated with 1- and 5-year survivals. Teenage donor hearts appear to be safe for transplantation in adult recipients. However, teenage donor hearts used for transplantation tend to be oversized with limited data available on undersized teenage donor hearts. Further assessment of the best sizing metrics is needed.