A computational framework for atherosclerotic plaque growth simulations

Temple University, Philadelphia PA

Investigators

Abstract

The investigators develop a computational framework for the growth of atherosclerotic plaques in large arteries. Specific emphasis is placed on the nonlinear constitutive models for the arterial wall, including residual stresses, and on the bridging of the highly separated time scales that govern this process. This study focuses on the incompressible Navier-Stokes equations that describe the blood flow, coupled with nonlinear elasticity equations that govern the response of the diseased arterial walls. The actual plaque growth process exhibits a large separation of time scales between the growth of the plaque, which takes place over a course of years, and the heart rate, which is in the order of seconds. The investigators develop a methodology to couple a growth model with the fluid-structure interaction problem in a way that the fundamental challenges incurred by the separation of time scales are resolved. In addition, the computational framework allows for the incorporation of variable behavioral factors, such as physical activity and cholesterol concentration in the blood. While it is known that the rupturing of an atherosclerotic plaque can cause a heart attack, the actual growth process of plaques in arteries is far from well understood. In this project, a computational framework is developed that bridges the highly separated time scales between the plaque growth and the heart rate, and that allows for the incorporation of accurate models for the elastic arterial walls. This new framework can yield fundamental insights into the long-term causes of atherosclerosis, and the dependence of the disease on behavioral factors such as physical activity, cholesterol intake, and tobacco use. In addition, the methodologies developed in this project can find applications in the modeling of damage in elastic materials, other diseases that develop over a large time span such as abdominal aortic aneurysms and intimal hyperplasia, and biological phenomena such as the growth and transport of algae in channel flows and the growth of biofilms. This project involves a collaboration with engineers who measure residual stresses in arteries experimentally.