A numerical study of the effects of blood rheology and vessel deformability on the hemodynamics of carotid bifurcation

Hemodynamic factors, such as Wall Shear Stress (WSS), play a substantial role in arterial diseases. In the larger arteries, such as the carotid artery, interaction between the vessel wall and blood flow affects the distribution of hemodynamic factors. In the present study, both rigid-wall and deformable-wall models are developed in a 3D numerical simulation to assess the effectiveness of arterial rigidity on worsening hemodynamics, especially WSS. Two different rheological models (Newtonian and CarreauYasuda) have been employed to evaluate the influence of blood, non-Newtonian properties, as well. The importance of vessel wall deformability was compared with the rheological model of blood. Although the deformability changes hemodynamic factors under the steady state boundary condition, or at the last two phases of the cardiac cycle (when the blood flow in carotid looks like a steady condition), WSS distribution is mostly affected by the blood rheological model. In other words, the influence of shear- thinning behavior at the end-diastolic phase of the cardiac cycle is undeniable unlike the deferability. However, the effects of deformability, like the rheology of blood on WSS could not be neglected at the first two phases of the cardiac cycle when pressure reaches its highest values.