Impaction of Regurgitation Jet on Anterior Mitral Leaflet Causes Diastolic Dysfunction in Patients With Bicuspid Aortic Valve and Mild Insufficiency: A Cardiovascular Magnetic Resonance Study

To assess the impact of regurgitant jet direction on left ventricular function and intraventricular hemodynamics in asympto- matic patients with bicuspid aortic valve (BAV) and mild aortic valve regurgitation (AR), using cardiac magnetic resonance (CMR) feature tracking and 4D flow imaging. Fifty BAV individuals were retrospectively selected: 15 with mild AR and posterior regurgitation jet (Group-PJ), 15 with regurgitant jet in other directions (Group-nPJ) and 20 with no regurgitation (Controls). CMR protocol included cine steady state free precession (SSFP) sequences and 4D Flow imaging covering the entire left ventricle (LV) cavity and the aortic root. Cine-SSFP images were analyzed to assess LV volumes, longitudinal and circumferential myocardial strain. Circumferential and longitudinal peak diastolic strain rate (PDSR) and peak diastolic velocity (PDV) were reduced in group PJ if compared to group nPJ and control group (PDSR = 1.10 ± 0.2 1/s vs. 1.34 ± 0.5 1/s vs. 1.53±0.3 1/s, p:0.001 and 0.68±0.2 1/s vs. 1.17±0.2 1/s vs. 1.05±0.4 1/s ; p<0.001, PDV = − 101.6±28.1 deg/s vs. − 201.4±85.9 deg/s vs. −221.6±67.1 deg/s; p<0.001 and −28.1±8 mm/s vs. − 38.9±11.1 mm/s vs. − 43.6±14.3 mm/s, p < 0.001, respectively), whereas no differences have been found in systolic strain values. 4D Flow images (available only in 9 patients) showed deformation of diastolic transmitral streamlines direction in group PJ compared to other groups. In BAV patients with mild AR, the posterior direction of the regurgitant jet may hamper the complete mitral valve opening, disturbing transmitral flow and slowing the LV diastolic filling.