Abstract 20514: Adults With Hypoplastic Left Heart Syndrome: Outcomes in a New Cohort of Patients

Abstract

Background: Surgical palliation of hypoplastic left heart syndrome (HLHS) has only been possible for the past few decades. Prior to this, without heart transplantation, HLHS was universally fatal in infancy. The oldest survivors of palliated HLHS are only now entering adulthood and limited data are available regarding their welfare. Methods: For this multi-center, cross-sectional, observational study, 6 adult congenital heart disease (ACHD) centers contributed data regarding all HLHS patients aged >18 years followed at their institution. HLHS was defined as a dominant right ventricle (RV) and diminutive left ventricle with a combination of mitral valve disease (stenosis [MS] or atresia [MA]) and aortic valve disease (stenosis [AS] or atresia [AA]). Patients with single RV physiology without hypoplasia of left heart inlet and outlet structures were excluded. All available clinical data, including cardiac imaging, cardiac catheterization results and exercise tests were reviewed. Results: The study included 53 HLHS adults (65% male) with mean age 21.8±3.6 years. Underlying cardiac anatomy was AA&MA (n=21, 41%), AS&MS (n=19, 37%), AS&MA (n=10, 20%), and AA&MS (n=1, 2%). Stage 1 Norwood was completed at age 6.0±4.4 days, Glenn shunt at age 10.8±8.7 months and Fontan at age 3.3±2 years. Stage 1 cardiopulmonary bypass and circulatory arrest times were 94±46 and 59±2 minutes respectively. The mean duration of follow-up in an ACHD center was 3.4±2.5 years. After age 18 years, major adverse events had occurred in 15/53 patients (28%). These mutually exclusive events were: death (n=3, 6%), transplant (n=1, 2%), protein losing enteropathy (n=2, 4%), stroke (n=2, 4%), symptomatic ventricular tachycardia (n=1, 2%), heart failure requiring admission for intravenous therapy (n=3, 6%) and major cardiac surgery (n=3, 6% [aortic valve replacement n=1, tricuspid valve replacement n=2]). Conclusions: Young adults with a Fontan palliation for HLHS are at high risk of major adverse cardiac events. It is essential that close attention is paid to successful transition of this vulnerable population into adult care and that these patients remain under vigilant specialist follow-up through adult life.