Impact of blood rheology on wall shear stress in a model of the middle cerebral artery

TL;DR

This study investigates how different blood rheology models affect wall shear stress predictions in cerebral artery simulations, highlighting that shear-thinning effects are significant only near certain pathological thresholds.

Contribution

It compares Newtonian and Carreau-Yasuda blood models using TBD analysis in cerebral artery flow, revealing conditions where rheology impacts wall shear stress predictions.

Findings

Differences between models are significant near specific shear stress thresholds.

Shear-thinning effects are negligible outside pathological threshold ranges.

TBD analysis effectively assesses rheology impact on vascular stress predictions.

Abstract

Perturbations to the homeostatic distribution of mechanical forces exerted by blood on the endothelial layer have been correlated with vascular pathologies including intracranial aneurysms and atherosclerosis. Recent computational work suggests that in order to correctly characterise such forces, the shear-thinning properties of blood must be taken into account. To the best of our knowledge, these findings have never been compared against experimentally observed pathological thresholds. In the current work, we apply the three-band diagram (TBD) analysis due to Gizzi et al. to assess the impact of the choice of blood rheology model on a computational model of the right middle cerebral artery. Our results show that, in the model under study, the differences between the wall shear stress predicted by a Newtonian model and the well known Carreau-Yasuda generalized Newtonian model are only significant if the vascular pathology under study is associated with a pathological threshold in the range 0.94 Pa to 1.56 Pa, where the results of the TBD analysis of the rheology models considered differs. Otherwise, we observe no significant differences.