A Fluid-Structure Interaction Model of Atherosclerosis at Abdominal Aorta

Abstract

Atherosclerosis is a form of cardiovascular disease that is a major contributing factor to death and disability worldwide. This study uses computational fluid dynamics (CFD) models as a cost effective and non-invasive method to determine the location and condition of atherosclerosis segments on the arterial wall. It also investigates changes in the abdominal aorta geometry including the inner and outer diameters, the length of the disease segments and the thickness of the arterial wall on the development of disease. Three groups of unhealthy conditions are assumed with each group having eight cases, which are compared to the control case of healthy condition. An invasive catheter pulsatile blood flow is imposed at the ascending aorta and pressure waveforms data is imposed at the four outlets of the aorta and also used to validate the present models. The results show that the stress phase angle at the brachial artery could be correlated to the early stages of atherosclerosis development at the abdominal aorta. This can be detected by measured values of the systolic wall shear stress and elastic strain intensity which increases due to the forward pulse wave resulting from atherosclerosis, while the diastolic values of stresses decreases due to the delay of the backward waves which reach the brachial artery. The three scenarios of atherosclerosis show that the forward and backward waves, which can be attributed to changes in the diameter, length and thickness of the abdominal aorta, can be non-invasively used to diagnose cardiovascular diseases.