Fluid Dynamics Characterization of Transcatheter Aortic Valves
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Aortic stenosis due to degenerative calcific aortic valvular disease is the most reason for aortic valve replacement in developed countries. Aortic stenosis affects up to 7% of the world population, and current clinical data indicate that the number of the affected people could be triple by 2050, due to population ageing and health lifestyle. Transcatheter aortic valve replacement (TAVR) was introduced as a minimal invasive treatment of severe aortic stenosis. Even though surgical aortic valve replacement (SAVR) is considered the golden standard treatment for severe aortic stenosis patients, TAVR showed equivalent or even superior outcome compare to SAVR. Currently, transcatheter aortic valves (TAVs) have limited clinical data in term of fluid dynamics performance of TAVs, in contrast to surgical aortic valves (SAVs). Due to limitations associated with devices that are used to evaluate the performance of TAVs in patients such as echocardiography, magnetic response imaging (MRI) and an accurate method to detect and evaluate any leakage. Thus, an experimental testing and computational modeling were performed to compare the performance of TAVs to SAVs in term of hemodynamic performance and addressing some clinical complications that are associated with TAV devices. Therefore, the objectives of this dissertation were to used particle image velocimetry (PIV) to obtain velocity and shear stress contours to indicate any damage to blood elements that could lead to stroke. Additionally, investigate the cause of reduced TAV leaflets motion post-TAVR procedure using blood residence time (BRT) approach. Furthermore, validating the current guideline uses to evaluate paravalvular leakage (PVL) severity and develop a new methodology to assess and evaluate the severity of PVL post-TAVR based on fluid dynamics. Moreover, developing and validating non-invasive procedure to estimate energy loss post-TAVR during the cardiac cycle iii and determine the workload imposes on the left ventricular. Thus, the main goal of this dissertation was to develop experimental testing to measure hemodynamics performance of TAVs and validating computational modeling output in term of flow field.