Impact of Operative Time on Pediatric Heart Transplant Outcomes: An Analysis of the United Network for Organ Sharing Registry

BACKGROUND: Heart transplantation is definitive therapy for children with end-stage heart failure. Because donor availability is unpredictable, transplantation occurs overnight or on weekends. Although studies report mixed findings on the association between operative timing and outcomes, pediatric data remain limited. We evaluated the impact of operative timing on pediatric heart transplant outcomes. METHODS: We studied pediatric heart transplant recipients (< 18 years) in the United Network for Organ Sharing registry from 2000 to 2018. Transplants were classified by time of day (day: 9 AM-8:59 PM; night: 9 PM-8:59 AM) and day of week (weekday vs. weekend). Primary outcome was survival. Secondary outcomes included graft survival, rejection, retransplantation, and postoperative complications. Survival was analyzed using Kaplan-Meier and log-rank testing. Multivariable Cox regression adjusted for recipient and donor characteristics and pre-transplant support. RESULTS: Among 6125 recipients, 2930 (47.8%) transplants occurred during the day and 3195 (52.2%) at night; 4408 (72.0%) occurred on weekdays and 1717 (28.0%) on weekends. Kaplan-Meier analysis demonstrated no significant survival difference between daytime and nighttime transplants (p = 0.266) or weekday and weekend transplants (p = 0.210). In multivariable Cox regression, operative timing was not associated with mortality (night vs. day: hazard ratio 0.97, 95% confidence interval 0.89-1.06, p = 0.554; weekend versus weekday: hazard ratio 1.04, 95% confidence interval 0.94-1.15, p = 0.445). Acute rejection prior to discharge and treatment for rejection within 1 year was more frequent in daytime transplants without affecting graft survival. CONCLUSIONS: Operative timing was not associated with patient survival, graft survival, or postoperative outcomes after pediatric heart transplantation.