Abstract 14618: Bicuspid Aortic Valve Morphology and Risk Factors of Abnormal Hemodynamics: An Experimental Investigation of Velocity, Vorticity and Eccentricity of Systolic Jet Stream, Using a Magnetic Resonance Imaging Compatible Pulsatile Flow Circulation System

Abstract

Introduction: Abnormal hemodynamics with bicuspid aortic valve (BAV) is influenced by the BAV morphology. However, due to the morphological variety, the relationship between BAV morphology and hemodynamics has not been well clarified. We experimentally investigated influences of BAV morphology on hemodynamics. Methods: An MRI compatible pulsatile flow circulation system incorporating an aortic valve model and morphologically relevant aortic arch model was developed. Two types of BAV models with cusp angles of 240-120 (asymmetric BAV) and 180-180 (symmetric BAV) were prepared using bovine aorta and pericardium. The vorticity and eccentricity of jet in the aortic arch model in systolic phase were assessed using 4D-flow MRI. Streamlines at peak systole were compared among 5 BAV morphologies defined based on the symmetry and the position of leaflets (Fig). Results: Eccentric supra-valvular jets directed to the aortic wall faced to the smaller leaflet were present in the 3 asymmetric BAVs. In the ABAV-1, a markedly eccentric jet impinging on the aortic outer curvature was present. In the ABAV-2, a left-posterior directed jet shifting to the outer curvature of proximal arch was present. The asymmetric BAVs induced larger flow vorticity in the ascending aorta than the symmetric BAVs (ABAV-1 vs -2 vs -3 vs SBAV-1 vs -2, 0.018 vs 0.019 vs 0.014 vs 0.010 vs 0.011 m 2 /s). The ABAV-2 had a larger vortex in the middle arch than the ABAV-1 (ABAV-2 vs -1, 0.010 vs 0.005 m 2 /s). Conclusion: Our study indicated that the angles and orientations of the BAV impacted on the locations of jets impinging on the aortic wall and magnitudes of vorticities in systole. In the asymmetric BAVs, the direction of jet was influenced by the position of smaller leaflet. Our data suggests that the ABAV-1 morphology may be a risk factor inducing asymmetric aneurysm bulged toward the aortic outer curvature, while the ABAV-2 morphology may be a risk factor of an aortic aneurysm involving the transvers arch.