Background: The univentricular heart with a predominant right ventricle morphology (uRV) has been associated with a higher rate of adverse cardiovascular events. It remains to be determined whether the specific type of uRV influences outcomes.
Methods and results: A North American multicenter retrospective cohort study was conducted by the Alliance for Adult Research in Congenital Cardiology on individuals with a uRV and total cavopulmonary connection Fontan. The incidence of a composite outcome consisting of all-cause mortality, cardiac transplantation, atrial arrhythmias, or thromboembolic events was compared among patients with Fontan palliation who had hypoplastic left heart syndrome (HLHS) versus other forms of uRV (non-HLHS). All components of the composite outcome were classified by a blinded adjudicating committee. Competing risks were taken into account in time-to-event analyses. A total of 171 patients with uRV of whom 76 (44.4%) had HLHS were followed for 10.2±5.7 years. The composite outcome occurred in 7.1 versus 2.1 cases per 100 person-years in patients with HLHS versus non-HLHS (P<0.0001). In multivariable analyses, HLHS was associated with a significantly higher risk of the composite outcome (hazard ratio [HR], 6.13 [95% CI, 2.92-12.69], P<0.001). Moreover, HLHS was associated with significantly higher rates of all components of the primary outcome.
Conclusions: Among patients with a uRV and Fontan palliation, HLHS is associated with a significantly higher rate of adverse cardiovascular events.
Keywords: Fontan surgery; hypoplastic left heart syndrome; univentricular heart.