EFFECT OF THE CAROTID GEOMETRY ON THE ONSET OF ATHEROSCLEROTIC PLAQUES

Atherosclerosis is an inflammatory cardiovascular disease characterized by the formation of plaques inside arteries. These plaques result from the accumulation of lipidic substances over the years and can obstruct blood flow to downstream vessels and organs. Our objective is to predict the possible onset of carotid plaques using Computational Fluid Dynamics (CFD) simulations and to analyze the influence of hemodynamic and geometric parameters on the early stages of the disease through stochastic sensitivity analysis. The ultimate goal is to determine whether geometric parameters can be considered risk factors. We combine CFD simulations with a model for predicting plaque onset and growth in the carotid arteries. In this model, plaque growth depends on CFD-predicted wall shear stresses and the concentration and accumulation of Low-Density Lipoprotein (LDL) in the vessel. Low values of wall shear stress and higher LDL concentrations promote plaque formation. Starting with a clinical dataset that includes 3D segmented geometries of the right and left carotids, as well as flow rate waveforms in the common, external, and internal carotid arteries (CCA, ECA, and ICA), we construct a parametric geometry to identify which geometric parameters describing the carotid bifurcation are primarily responsible for the possible onset and growth of arteriosclerotic plaques. Continuous response surfaces of plaque growth in the geometrical parameter space are obtained using a probabilistic framework based on stochastic collocation methods and sparsification. Results indicate that the position of the ICA inflection point significantly impacts the location and extent of the plaque. The Reynolds number also plays a role in plaque development, as it directly affects the magnitude of wall shear stresses.