Pathogenesis of atherosclerosis and its influence on local hemodynamics: A comparative FSI study in healthy and mildly stenosed carotid arteries

Atherosclerosis is one of the most dangerous forms of Cardiovascular disease (CVD) due to its asymptomatic nature during its early stages of development. The carotid sinus is a favorable location for plaque progression because of the temporal disturbances experienced in its environment. By performing a transient Fluid-Structure Interaction (FSI) on a healthy idealized carotid artery, zones of low Wall Shear Stress (WSS) were isolated as these regions are prone to plaque formation. A plaque was then constructed in the vicinity of these zones leading to lumen stenosis. The influence and variation of critical hemodynamic parameters such as WSS, Oscillatory Shear Index (OSI), and helicity were then analyzed in the stenosed artery, and compared to that of the healthy one. Significant variation in vessel deformation, an FSI exclusive parameter, was seen due to atherosclerotic obstruction near the bifurcation apex. Elevated WSS, OSI, and velocity levels were observed, especially around the sinus. Regions with low helical intensity corresponded to high particle residence times which originated at the sinus and developed well into the Internal Carotid Artery (ICA). All signs point to further progression of atherosclerosis, with high OSI and RRT indicating a further increase in the degrees of stenosis, or potential thrombus formation at the carotid sinus in case of plaque rupture due to increased velocity and WSS levels.