A comparison of Newtonian and non-Newtonian pulsatile blood rheology in carotid bifurcation through fluid–solid interaction hemodynamic assessment based on experimental data

Abstract

Endothelial cells play a crucial role in the arterial homeostasis. In addition to physiological risk factors, abnormal levels of hemodynamic parameters induced by the pulsatile flow contribute to atherosclerotic plaque formation and development. In this study, we used an experimental setup to study the hemodynamics of Newtonian and non-Newtonian blood flow on a deformable model of human carotid bifurcation. The flow/pressure pulses of the experimental model were fed into a fluid–structure interaction numerical model, and respective hemodynamic parameters were obtained and compared between the two flow regimes. Results revealed noticeable differences among the two flow regimes when the pulsatile nature of blood flow and pressure were considered, with more distinct differences near junction sites. Velocity profiles of the non-Newtonian model were more flattened with higher back flow during the diastole. The shear stress waves as well as shear-dependent parameters, such as oscillatory shear index, relative residence time, and vorticity, as well as wall stress and strain, also indicated significant differences among the two models. Regardless of flow regime, results showed a good agreement with clinical outcomes in human carotid bifurcation, especially the carotid sinus. Near the bifurcation, marked fluctuations of shear stress are evident. Around the junction site, wall pulsation experienced variations up to five times of the normal pulse span. The quantified hemodynamic parameters obtained from proposed accurate model of carotid bifurcation may help to achieve technological solutions to adjust the out of biological ranges of these parameters, and avoid atheroma formation or treat the diseased artery.