Rheological Properties of Blood Flow in Arterial Stenosis

Abstract

One of the leading causes of death worldwide is heart disease. Heart disease is a collective term used to describe several conditions, many of which are related to the buildup of plaque in the walls of blood vessels. Blood is a bodily fluid that circulates to locations near all of the cells that make up the organs and tissues of the human body where oxygen and nutrients exchange with cellular waste products. Plaque is made up of mostly fat, cholesterol, and other substances found in the blood. An arterial stenosis occurs when the buildup of plaque narrows the lumen of the artery, making it more difficult for blood to flow.  In order to better understand the blood flow in an arterial stenosis, it is important to investigate the rheological properties of blood. Blood is often classified as a non-Newtonian fluid due to the behavior of red blood cells and the nonlinear relationship observed between blood viscosity and shear rate. The rheological characteristics of blood, such as shear thinning, yield stress, and viscoelasticity, are described using one of several mathematical expressions. These rheological equations are applied to the conservation of linear momentum for a cylindrical tube system, resembling an artery, with and without stenosis formation. Velocity profiles for blood flow are developed for the Newtonian, Power law, and Casson fluid models. These velocity profiles are compared numerically using blood viscosity parameters found in the literature to determine the impact of the stenosis formation on blood flow.