Abstract 13294: Valve Mediated Hemodynamics and Their Association With Ascending Aortic Diameter in Bicuspid Aortic Valve

Abstract

Introduction: Bicuspid aortic valve (BAV) is the most common congenital heart defect, affecting 1-2% of the US population. Valve-mediated hemodynamics have been postulated to contribute to the cause and progression of ascending aorta (AAo) disease. Hypothesis: Aortic valve morphology and hemodynamics affect distal AAo diameter in subjects with BAV disease. Methods: Four-dimensional flow MRI was used to evaluate the hemodynamics in the proximal AAo of 52 subjects: size-matched controls with tricuspid aortic valves (n = 24) and BAV patients with aortic dilatation (n = 14 right and left coronary cusp fusion (RL-BAV); n = 14 right and non-coronary cusp fusion (RN-BAV)). A semi-automated technique was used to systematically quantify hemodynamic metrics (flow angle, flow displacement, and jet quadrant) and valve morphology (orifice circularity) for all subjects, as illustrated in the figure. A regression analysis was conducted to develop a relationship between upstream hemodynamics and distal AAo diameter. Results: RN-BAV subjects displayed a stronger correlation between hemodynamic metrics in the proximal AAo with diameter in the distal AAo when compared to size-matched TAV controls and RL-BAV subjects. The distal AAo diameter was found to be strongly correlated to the flow displacement (R 2 adjusted = 0.75) and flow angle (R 2 adjusted = 0.66) measured at the sino-tubular junction (STJ) in RN-BAV subjects. Orifice circularity was also strongly correlated (R 2 adjusted = 0.53) to the proximal AAo diameter in RN-BAV subjects. Conclusions: The findings in this work demonstrate that the hemodynamics in the STJ are significantly correlated to the distal AAo diameter in RN-BAV subjects. The hemodynamic metrics demonstrated more statistical significance than valve morphology when considering correlations to distal aortic size. These results could be used to design efficient imaging protocols for better prognosis of BAV-related aortopathy.