Partial Heart Transplant for Congenital Heart Disease.

Importance: Partial heart transplant, or living valve replacement, has the potential to advance surgical management of irreparable valvular disease by providing a viable option with capacity for growth. Objectives: To describe the early experience and assess the feasibility, safety, and efficacy of partial heart transplant in patients with congenital heart valve disease. Design, Setting, and Participants: Case series of the first 19 patients to undergo partial heart transplant at a single high-volume pediatric cardiac surgery and transplant center in the US between April 2022 and December 2024. No patients were excluded or lost to follow-up. Exposures: Partial heart transplant using semilunar valves from donor hearts. Maintenance immunosuppression consisted of tacrolimus monotherapy with a trough level goal of 4 to 8 ng/mL. Main Outcomes and Measures: Efficacy was defined as growth of the transplanted valve annulus and leaflets over time. Secondary outcomes included valve dysfunction and complications related to immunosuppression. Results: Among the 19 participants with irreparable congenital heart valve dysfunction, 53% were male and 47% female. The median age at the time of transplant was 97 days. The median follow-up was 26 weeks. Three patients received partial heart transplant of both semilunar valves, 7 underwent living pulmonary valve replacement in the pulmonary position, 2 had a living aortic valve allograft in the aortic position, and 7 had a living aortic valve allograft in the pulmonary position. Nine patients constituting the initial cohort of partial heart transplant recipients had their annular diameter and valve leaflet length longitudinally analyzed for growth. All valves functioned well and demonstrated growth along appropriate z scores. Annular diameter increased from medians of 7 mm (aortic valve) and 9 mm (pulmonary valve) to 14 mm (aortic valve) and 17 mm (pulmonary valve), respectively. Leaflet length similarly increased from medians of 0.5 mm (aortic valve) and 0.49 mm (pulmonary valve) to 1 mm (aortic valve) and 0.675 mm (pulmonary valve), respectively. One patient required reoperation unrelated to the implanted valve. No significant complications related to immunosuppression were observed. Conclusions and Relevance: Partial heart transplant appears feasible, safe, and efficacious. All transplanted valves demonstrated growth based on annular and leaflet length measurements. Careful follow-up and monitoring are crucial to support the continued expansion of this novel technique.