Cardiac allograft vasculopathy and survival in pediatric heart transplant recipients transitioned to adult care

BACKGROUND: Cardiac allograft vasculopathy (CAV) is an important cause of mortality after pediatric heart transplantation (HT) but there is a paucity of data regarding its incidence and impact on survival in pediatric recipients transitioned to adult care. METHODS: We conducted a retrospective review of consecutive pediatric HT patients from 1989 to 2017 at the Hospital for Sick Children who transitioned to adult care at ≥18 years at Toronto General Hospital. We evaluated the incidence of International Society of Heart and Lung Transplantation CAV grade ≥1 using competing risk models. We assessed the association between all-cause mortality and CAV using Cox proportional hazards and used Kaplan Meier methods to evaluate all-cause mortality stratified by CAV and transplant era (1989-2001, 2002-2017). RESULTS: Ninety-six patients were transitioned to adult care by January 2022, of which 53 underwent repeat coronary angiography as adults. CAV was newly diagnosed in 49% patients after transition to adult care. The overall incidence of CAV was 3.9 cases per 100 person-years. There was no difference in the adjusted incidence of CAV according to transplant era (subdistribution hazard ratios = 1.17, 95% confidence interval (CI) 0.54-2.66). CAV was associated with a higher risk of death in the early era (hazard ratio (HR) 10.29, 95% CI 2.16-49.96), but not in the recent era (HR 1.61, 95% 0.35-7.47). CONCLUSIONS: There is a role for continued CAV surveillance after the transition to adult care. The implications of diagnosing CAV after the transition to adult care require further study, particularly because the risk of death in pediatric HT recipients diagnosed with CAV in the more recent era may be attenuated compared to the earlier HT era.