Differences in Flow-Gradient Patterns Between Severe Bicuspid Aortic Stenosis and Severe Tricuspid Aortic Stenosis　― Mechanistic Insight From Multimodal Imaging

Background:We investigated the flow-gradient pattern characteristics and associated factors in severe bicuspid aortic stenosis (AS) compared with severe tricuspid AS.Methods and Results:A total of 252 patients with severe AS (115 bicuspid vs. 137 tricuspid) who underwent aortic valve (AV) replacement were retrospectively analyzed. Patients were classified into 4 groups according to stroke volume index and mean pressure gradient across the AV [normal-flow–high-gradient (NF-HG), low-flow–high-gradient, normal-flow–low-gradient, low-flow–low-gradient (LF-LG)]. In 89 patients who underwent cardiac computed tomography (CT), influential structural parameters of the left ventricular outflow tract (LVOT), AV and ascending aorta were assessed. Bicuspid AS was more likely to present a NF-HG pattern (83.5% vs. 64.2%, P