Carotid arteries are the major blood vessels that carry oxygenated blood to the brain and face. Carotid artery disease is characterized by the narrowing of the carotid arteries due to plaque buildup at the arterial walls, leading to major consequences such as brain stroke and death. Hemodynamics such as wall shear stress (WSS) and velocity distribution can be employed to investigate the severity and location of stenosis in the carotid arteries. Furthermore, the potential of stenosis in other regions along the carotid arteries is affected by local variations in hemodynamics. To investigate other potential high-risk regions, a comprehensive blood flow model was utilized through a reconstructed three-dimensional patient-specific geometry with realistic boundary conditions. The developed model was numerically simulated and validated. The results indicated that hemodynamics can be successfully used to investigate the degree of stenosis severity and location. Two different locations along the carotid artery were examined. At location 1 (near the artery bifurcation) of the common carotid artery, the WSS increased from 11 Pa in the case of 42% stenosis to 27 Pa in the case of 61% stenosis and 263 Pa for 84% stenosis. Such values significantly decreased at location 2 (far from the artery bifurcation) because of the increasing distance from the artery bifurcation. In addition, the maximum value of the oscillatory shear index (OSI) downstream of the stenosis throat reached 0.5, and the outlet mass flow rate changed significantly with varying stenosis location. Carotid artery stenosis affects the artery bifurcation, which appears to be at high risk because of thrombus and arterial wall rupture, which are clearly indicated by the WSS and OSI values in this region. The current findings support the efficient use of a computational fluid dynamics approach for the diagnosis and prediction of carotid artery stenosis.

Cardiovascular system abnormalities can result in serious health complications. By using the fluid–structure interaction (FSI) procedure, a comprehensive realistic approach can be employed to accurately investigate blood flow coupled with arterial wall response. The hemodynamics was investigated in both the coronary and carotid arteries based on the arterial wall response. The hemodynamics was estimated based on the numerical simulation of a comprehensive three-dimensional non-Newtonian blood flow model in elastic and rigid arteries. For stenotic right coronary artery (RCA), it was found that the maximum value of wall shear stress (WSS) for the FSI case is higher than the rigid wall. On the other hand, for the stenotic carotid artery (CA), it was found that the maximum value of WSS for the FSI case is lower than the rigid wall. Moreover, at the peak systole of the cardiac cycle (0.38 s), the maximum percentage of arterial wall deformation was found to be 1.9%. On the other hand, for the stenotic carotid artery, the maximum percentage of arterial wall deformation was found to be 0.46%. A comparison between FSI results and those obtained by rigid wall arteries is carried out. Findings indicate slight differences in results for large-diameter arteries such as the carotid artery. Accordingly, the rigid wall assumption is plausible in flow modeling for relatively large diameters such as the carotid artery. Additionally, the FSI approach is essential in flow modeling in small diameters.

The hemodynamics of elastic cerebral aneurysms are complicated by phenomena that affect the initiation and the progress of each aneurysm. The blood vessel deforms with pulsatile flow. In a phantom, however, it remains unclear whether the wall compliance can be neglected. In our previous study, the flow structure at another plane oriented perpendicular to the median plane was not clarified. In the approach presented here, an identical phantom is used for both the rigid and elastic wall models by adjusting the surrounding fluid when immersed in a bath. For this purpose, the full-scale phantom of an aneurysm was fabricated using a silicone elastomer. The hemodynamic factors at the orthogonal planes in the non-deformable and deformable models of the bifurcation in the middle cerebral artery were examined. Using two-dimensional particle image velocimetry, the flow velocity, the wall shear stress (WSS), the WSS gradient (WSSG), and the turbulent kinetic energy (TKE) were measured during pulsatile flow. Overall, the WSSG at the median plane is smaller than that at corresponding perpendicular plane. Additionally, the TKE in the deformable model is smaller than that in the non-deformable model. Our results have clarified the complex effects of aneurysm wall compliance on these hemodynamic factors.

Atherosclerosis is a major arterial disease characterized by the thickening and hardening of the arteries walls due to the deposition of cholesterol and other lipids beneath the internal layer of the artery and plaque development. Carotid artery stenosis is one of the leading causes of morbidity and mortality in all countries. Blood flow is affected by the smoothness of the

Stenosis is the abnormal narrowing of a blood vessel structure. One of the main causes of stenotic lesions is atherosclerosis, a progressive disease in which the lumen of an artery narrows due to the build-up of fatty plaque. It is usually asymptomatic in early stages, but as the disease progresses, it can lead to serious complications such as coronary artery disease (CAD), stroke,