Abstract 4138483: Outcomes of Hypoplastic Left Heart Syndrome by Subtype and Presence of Ventriculocoronary Connections: A Fetal Heart Society Multi-Center Retrospective study

Background: Hypoplastic left heart syndrome (HLHS) is classified by subtype: mitral atresia and aortic atresia (MA-AA), mitral stenosis and aortic atresia (MS-AA), and mitral stenosis and aortic stenosis (MS-AS). It is controversial whether specific HLHS subtypes and presence of ventriculocoronary connections (VCC) are associated with transplant-free survival. We aimed to determine whether there is an increased risk of mortality associated with specific HLHS subtypes, whether this risk is stratified by the presence of VCC, and if a specific type of stage I palliation in patients with VCC improves survival. We also aimed to determine practice variation in the evaluation of HLHS patients with VCC. Methods: We performed a multicenter retrospective cohort study of fetuses and infants < 2 months of age with HLHS admitted between 1/2012-12/2016 to participating Fetal Heart Society institutions. Patients with HLHS variants were excluded. We collected patient specific data and surveyed participating centers for practice variation. Kaplan-Meier curves with log-rank test were used to assess transplant-free survival and cox proportional hazard analysis was performed with adjustment for center as a random intercept. Results: 341 patients from nine centers were included. MA-AA was the most common subtype (177, 52%), followed by MS-AA (102, 30%), and MS-AS (62, 18%). VCC were diagnosed or suspected in 65 patients (19%). A total of 287 patients were live born with intention to treat. HLHS subtype was not associated with transplant-free survival (Figure 1A). Presence of VCC was associated with a lower transplant-free survival (p=0.026, Figure 1B). In the subset of patients diagnosed with VCC, there was not a significant difference in survival based on type of stage I palliation (Figure 1C). Cox proportional hazard modeling adjusted for center demonstrates that presence of VCC has a hazard ratio of 1.74 (CI 1.02-2.98), p =0.04. Survey data regarding practice variation for patients with VCC (Figure 2) demonstrates 33% of centers modify the type of stage I palliation based on presence of VCC. Conclusions: In a multicenter cohort of HLHS patients, patients with VCC had lower transplant-free survival compared to those without VCC, while subtype and type of stage I palliation did not have a statistical difference. There is considerable practice variation in the management of HLHS patients with VCC that may warrant further investigation.