Influences of vascular geometry and blood property on carotid artery hemodynamics

Computational fluid dynamic (CFD) model is used to evaluate cardiovascular hemodynamics and the model is useful to predict the blood flow pattern and the wall shear stress (WSS) in various conditions. This study used the CFD model to assessment the influence of varied blood conditions and geometries on changing of velocity ratio at the internal carotid artery (ICA) and the external carotid artery (ECA). The realistic model of two-dimensional carotid artery was acquired from four normal male subjects with a magnetic resonance angiography. Then, the geometries were reconstructed and blood was assumed to be incompressible and Newtonian fluid. The artery was assumed to be a rigid wall. Four conditions simulated in this study were normal, 50% stenosis, hyperglycemia and hyperglycemia with 50% stenosis. The ICA velocity ratio was calculated from ICA velocity to inlet velocity and the ECA velocity ratio was calculated from ECA velocity to inlet velocity. The WSS was determined at inner and outer walls of ICA. The results showed that the trends of the velocity ratio increased in stenosis condition. The results also indicated that the velocity in ICA and ECA can be influenced by the geometries of carotid artery such as curvature and vascular stenosis. Moreover, the increase of velocity correlated with the WSS value.