Abstract 14116: Favorable Outcomes for Heart Transplantation in Barth Syndrome as Demonstrated by Multicenter/multiregistry Analysis

Abstract

Introduction: Barth Syndrome (BTHS) is a rare (~1/350,000), X-linked mitochondrial disease characterized by cardioskeletal myopathy and neutropenia. Reported outcomes after heart transplant (HT) are limited to case reports. We sought to identify a large cohort of BTHS HT recipients to describe clinical outcomes. Hypothesis: HT in BTHS is associated with non-inferior survival, acute rejection (AR), infection, and vasculopathy (CAV) relative to non-BTHS dilated cardiomyopathy (DCM). Methods: We analyzed data from the Barth Syndrome Registry and Repository (BRR), Pediatric Heart Transplant Society (PHTS), and Scientific Registry of Transplant Recipients (SRTR). To avoid recounting patients occurring in >1 source, we used years of birth, listing, and HT and listing/HT city to link records across registries. BTHS HT recipients were matched 1:4 on age, era, urgency status, and use of ECMO/VAD to male, non-BHTS, DCM HT recipients in PHTS. Survival was analyzed for all BTHS HT recipients. Because BRR and SRTR morbidity data are limited, AR, infection, malignancy, and CAV were analyzed only for those with PHTS data. Results: Forty-seven BTHS patients with 51 listings and 43 HTs (including 2 re-transplants) were identified; 29 BTHS HTs (1 re-transplant) had data in PHTS. Median age at HT was 1.9 yrs (IQR: 0.6-5.8) with 35% <1 years-old at HT. Median follow up was 4.2 yrs (2.1-9.1). Mechanical circulatory support at HT was common (VAD 29%, ECMO 5%). We found no difference in survival between BTHS and non-BTHS HT recipients (HR 0.93, 95% CI 0.40-2.14). Freedom from infection (HR 0.63, 0.33-1.20), bacterial infection (HR 0.76, 0.29-1.99), malignancy (HR 0.22, 0.02-2.02), and CAV (HR 0.55, 0.15-1.97) were also similar between the groups. BTHS HT recipients had greater freedom from AR (HR 0.39, 0.17-0.87). Use of induction therapy (62 vs 74%, p=0.21), steroids at 30 days (76 vs 62%, p=0.17), and dual or triple immunosuppression at 1 year (80 vs 84%, p=0.58) were similar for BTHS and non-BTHS recipients. Conclusions: In this largest cohort yet reported, BTHS HT recipients show equivalent survival and freedom from infection, malignancy, and CAV, with a lower risk of acute rejection. Thus, individuals with BTHS should not be excluded from HT solely based on the diagnosis of BTHS.