Fluid–Structure Interaction (FSI) Modelling in Stenotic Carotid Artery Bifurcation

Carotid artery stenosis occurs when the carotid artery becomes narrowed or blocked caused by a build-up of fatty deposits. Computational fluid dynamics (CFD) can be used to study the hemodynamics parameters in the stenosed carotid, i.e., velocity profiles, blood pressure, and wall shear stress. However, the CFD simulation is limited to a rigid arterial wall condition and ignore the influence of the wall compliance. This study investigated the interaction of blood flow and the stenosed carotid wall using fluid–structure interaction (FSI) model. Two generally used arterial wall models, i.e., elastic and hyperelastic models, were used for comparison purpose. In the fluid domain, Reynolds-averaged Navier–Stokes (RANS) method with a transitional version of the shear stress transport (SST-Tran) model was used to simulate the blood flow in a severe stenotic carotid geometry. The stresses produced by the blood flow in CFD was transferred and mapped onto the inner carotid wall for the finite element simulation. The low wall shear stress (WSS) contours showed a potential expansion of plaque deposition at downstream area of the existence stenosis. The totals wall deformation and von Mises stress equivalent varied significantly between the two models, with the hyperelastic model showing higher deformation and lower stress. The thickness of the wall model also affected the deformation and stresses, with a thicker wall showing lower deformation and stress, hyperelastic Mooney–Rivlin model is more suitable for modelling soft biological tissues like the carotid artery due to their ability to account for large deformations and nonlinear stress–strain behavior. Elastic models, on the other hand, assume linear stress–strain behavior and are better suited for modelling rigid materials. The Mooney–Rivlin model has been found to provide a good fit for many types of biological tissues, making it a popular choice for modelling soft biological structures like the carotid artery.