| Heart failure (HF) occurs when the heart pumping fail to convey enough oxygenated, nutrients-rich blood to the organs. Over 5 million Americans suffers from HF and about four thousands of patients on the waiting list for heart transplantation. However, considering the shortage of healthy donor hearts and transplantation compatibility, Left Ventricle Assist Device (LVAD) was widely transplanted to the patient with end-stage HF while lacking donor heart.;The LVAD is a pump that surgeons connect to the heart and aorta of heart failure patients, and boosts the blood flow to the tissues of the body. The wide applications of LVAD save numerous patients and enhance their life quality. However, implantation causes the alterations of hemodynamic and biomechanics. When the LVAD is pumping, the pressure in the heart is lowered, which affects the biomechanics of the aortic valve (AV), producing a decrease in opening area and duration as well as a reduction in flow through the aortic valve. These alterations may result in changes in the shear across the AV leaflets, which is an important signal for maintaining valve function. It is not known how the changes in biomechanics produced by the LVAD affect shear stress on the ventricular side of the AV leaflets.;Our goal is to assess the shear alteration trend on the aortic valve leaflets during different LVAD support conditions. Our initial hypothesis is that ventricular wall shear stress remains constant as LVAD speed increases. The experiment was operated in the SDSU cardiac simulator by the previous study, and the hemodynamic data was recorded in the LabView system. Then theoretical calculation based on Wormaley equation was performed according to the data analyzed from the Labview system by Matlab and LabChart.;To validate the theoretical assumption, Computer Assis Engineering (CAE) was adopted. The approach was to develop a computational model of the AV that could be solved for different levels of LVAD support. Eight 3¬D models of the AV and root were developed via SolidWorks to match the experimental measurements. ANSYS CFD and ICEM CFD are applied to simulate the AV subjected to the loading conditions reported by the experiments. |
