Biomechanical bases of forecasting occurrence of carotid atherosclerosis

Abstract

This paper is dedicated to numerical investigation of the bifurcation of the carotid artery in normal and atherosclerotic lesion behavior. The simulation results are analyzed in order to investigate the influence of mechanical characteristics of plaque on the carotid bifurcation behavior. The final system of equations was solved by finite element method using ANSYS software. To calculate the blood flow, ANSYS CFX module has been selected, and the calculation of stress-strain state of the wall was carried out in Structural module (Mechanical). The stress-strain state of atherosclerotic plaques was analyzed: soft plaque is substantially differs from hard plaque, which creates conditions for the plaque rupture under the influence of blood pressure and shear stress. The stress difference between hard plaque and healthy vessel in case of carotid stenosis creates additional streams and vortexes, leading to plaque progression and the development of mural thrombosis. Swirling of the flow and area of stagnation formation in the ampulla of the internal carotid artery creates conditions for the further plaques progression. An increased effective stress level at the junction of sections of the healthy vessel and atherosclerotic area in the case of soft plaque creates conditions for the separation of plaques and further thrombus formation. Analysis of the distribution of hemodynamic forces indicates weaknesses in the ampulla and the site of bifurcation of the carotid arteries, which should be considered when applying anastomosis during reconstructive surgical interventions.