Simulation of blood flow through atherosclerotic intracranial arteries, veins, and aneurysms

Abstract

Atherosclerosis is the formation of plaque in arterial walls, thickening the blood vessel wall, thereby hardening and obstructing blood flow through the arteries. An aneurysm is an atypical enlargement or bulge in the wall of a blood vessel inside an artery caused by a weakening of the arterial wall. Arise in fatalities due to atherosclerosis and aneurysms has been considered a hazard to health worldwide. This is mostly attributed to irregular blood flow in stenotic arteries. Thus, blood flow analysis through stenosed arteries and aneurysms is vital in the treatment process. Hence, various researchers have worked on finding the appropriate rheological model for blood flow simulations through arteries and aneurysms. This research study investigates various non-Newtonian rheological models to find the most appropriate model for blood flow simulations. A steady, incompressible, non-viscous, laminar blood flow through different geometrical domains on stenosis and an aneurysm is considered using five different non-Newtonian rheological models; Power law, Carreau law, Carreau-Yasuda law, HerschelBulkley law, and Casson law. COMSOL Multiphysics has been used to examine the velocity and pressure variations of blood flow for a range of simulated domains. The simulation through the ballonlike protrusion in a bulged arterial wall reveals that almost all models give very similar results for velocity and pressure distribution concluding that all five non-Newtonian models are suitable for the analysis. A striking change in pressure was observed in the area where the bulge is located. When considering an aneurysm type domain of a protrusion at the juncture between two arteries the velocity and pressure variations through the swelling area delineates a drastic change for the Herschel-Bulkley model with regard to other models. However, the remaining rheological models have approximately the same values outlining the minuscule deviations from one another. Hence, Herschel-Bulkley model is not appropriate in blood flow simulation of bulge near arterial junction aneurysms as for our work. The flow parameter variations in a stenosed arterial wall are also simulated and it was observed that all the rheological models are perfect for the modelling of velocity variation. As for the pressure variation determination it can be presumed that the values of the Power law, Herschel-Bulkley law, and Casson law models are exactly the same, while approximately similar values are observed in the remaining models. Further, a mathematical model describing plaque formulation has been analysed and simulated. The results of the simulations conclude that when the plaque growth obstructs the blood flow through an artery, the sporadic microscopic increase in pressure and a decrease in velocity near the lesion swelling area.