Hemodynamic assessment of severely stenotic carotid arteries

Internal carotid artery (CA) stenosis is a primary etiological factor for stroke and transient ischemic attack. The severity of arterial stenosis significantly impacts patient health and treatment decisions. Therefore, we conducted computational fluid dynamics analyses on five carotid arteries (CAs) of severe stenosis and compared them with five CAs in the control group. We improved the three-element Windkessel model method by pre-calculating the constant-pressure outlet simulation of the first cardiac cycle, which accelerated the stability of the model. The research results show that vortices were observed at the bifurcation of the CAs in the control group, whereas in the severe stenosis group, vortices predominantly occurred within the carotid sinus downstream of the stenotic segment. Notably, the vortex flow in the carotid aneurysm downstream of the stenotic segment arises due to the cross-sectional constriction induced by stenosis, which always flows in a clockwise direction and may contribute to the formation of aneurysms distal to the stenotic region. A high time-averaged wall shear stress value can effectively identify the stenosis site of CAs, while a high relative residence time value marks the protrusion near the stenosis segment. This study delved into the hemodynamic parameters between the CAs of the severe stenosis group and the control group and provided robust clinical evidence for carotid atherosclerotic disease.