The Congenital Bicuspid Aortic Valve can Experience High Frequency Unsteady Shear Stresses on its Leaflet Surface

Abstract Bicuspid aortic valve (BAV) is a common congenital malformation affecting 1-2% of the population and is highly correlated to early calcification of the valve leaflets. Two widely held hypothesis for this correlation are (1) altered shape of the BAV results in altered fluid mechanical environment, leading to pro-calcification biology responses, and (2) inherent genetic defects results in pre-disposition of the tissues to calcify. In the current study, we tested the first hypothesis with porcine valve models in an in vitro flow loop. One BAV model and one tricuspid aortic valve (TAV) model were constructed using healthy porcine AV leaflets and tested in a physiological pulsatile flow loop. Fluid velocities near the center of the aortic surface of the valve leaflets were measured with Laser Doppler Velocimetry at a spatial resolution of 89 microns, and ensemble average shear stresses were calculated at various time points in the cardiac cycle. Unsteadiness of flow near the valve leaflets was quantif...