This study investigated the impact of paravalvular leakage (PVL) in relation to the different valve openings of the transcatheter aortic valve implantation (TAVI) valve using the fluid structure interaction (FSI) approach. Limited studies were found on the subject of FSI with regards to TAVI-PVL condition, which involves both fluid and structural responses in coupling interaction. Hence, further FSI simulation with the two-way coupling method is implemented to investigate the effects of hemodynamics blood flow along the patient-specific aorta model subjected to the interrelationship between PVL and the different valve openings using the established FSI software ANSYS 16.1. A 3D patient-specific aorta model is constructed using MIMICS software. The TAVI valve identical to Edward SAPIEN XT 26 (Edwards Lifesciences, Irvine, California), at different Geometrical Orifice Areas (GOAs), is implanted into the patient’s aortic annulus. The leaflet opening of the TAVI valve is drawn according to severity of GOA opening represented in terms of 100%, 80%, 60%, and 40% opening, respectively. The result proved that the smallest percentage of GOA opening produced the highest possibility of PVL, increased the recirculatory flow proximally to the inner wall of the ascending aorta, and produced lower backflow velocity streamlines through the side area of PVL region. Overall, 40% GOA produced 89.17% increment of maximum velocity magnitude, 19.97% of pressure drop, 65.70% of maximum WSS magnitude, and a decrement of 33.62% total displacement magnitude with respect to the 100% GOA.

The application of numerical methods like CFD to understand hemodynamics in arteries has excellent potential to solve complex flow problems. In recent years, CFD has been primarily used in the hemodynamics of the carotid artery due to advances in computational resources. This technique is widely used to obtain knowledge on hemodynamics, predict the risk factors for the development and progression of the atherosclerotic lesion, and analyze local flow profiles due to changes in the carotid artery geometry. This fundamental study will be supportive in observing the blood flow behavior through arteries and studying arterial diseases. The present study investigates three different subject-specific carotid bifurcation models under altered blood pressure conditions. Subject-specific 3D carotid bifurcation modeling is carried out using Materialize software. Unsteady flow simulation is conducted in ANSYS Fluent under the rigid wall and Newtonian conditions. The haemodynamic parameters such as vorticity, helicity, and time-averaged wall shear stress (TAWSS) were evaluated to understand better the beginning and progression of atherosclerotic plaques in the bifurcation. Also, the influence of geometric variation in the bifurcation region was investigated, and it was observed that this region causes significant vortex formation zones. A noticeable reduction in velocity and backflow formation was observed, which reduced the shear stress. It is established that the regions of low TAWSS along the bifurcation region are likely to develop atherosclerosis.