Abstract 12344: Effect of Valved versus Non-Valved Conduits in Norwood Procedure on Ventricular Size and Function in Stage I Palliation for Hypoplastic Left Heart Syndrome

Abstract

Background: Mortality in the interstage period remains high in hypoplastic left heart syndrome (HLHS) after introduction of the right ventricle (RV) to pulmonary artery conduit to the Norwood procedure. Prior studies have not shown long term survival benefit with conduits, possibly due to regurgitation and volume load, which may cause decreased RV function. Valved conduits (VC) were introduced more recently to address these limitations. Hypothesis: The goal of the study was to assess differences in RV size and function during the interstage period between patients undergoing Norwood procedure with valved versus non-valved conduits (NVC). We hypothesized that patients with VC would have smaller increases in RV size and improved function compared to those with NVC. Methods: Twenty-five consecutive neonates with HLHS who underwent Norwood procedure with VC were compared to 25 consecutive neonates who underwent Norwood with NVC from 2013 and 2022. Primary outcomes were RV size measured by end diastolic area (EDA) on 4-chamber images and function measured by RV fractional area change and global longitudinal strain. Results: Most patients with VC (96%) did not develop more than mild conduit regurgitation. There was no difference in EDA increase one month post op between groups, but there was a significantly smaller increase in EDA pre-Glenn compared to baseline in the VC group (Table 1). Functional measures were not significantly different during follow up. There was no difference in interstage cardiac events or mortality. Conclusions: Patients with VC at time of Norwood had smaller increases in ventricular size compared to those with NVC, but there were no differences in functional parameters during follow up. It is possible decreased volume load will have a beneficial long term effect on the immature myocardium of infants with HLHS. Larger studies are needed to further examine the hemodynamic benefits of VC in the interstage period and throughout the stages of palliation.