A patient-specific method for the evaluation of wall shear stress in human coronary arteries

Atherosclerotic plaques form at specific sites of the arterial tree, an observation that has led to the "geometric risk factor" hypothesis for atherogenesis. It is accepted that the location of atherosclerotic plaques is correlated with sites subjected to low abnormal values of wall shear stress (WSS), which is in turn determined by the specific geometry of the arterial segment. In particular, the left coronary artery (LCA) is one of the most important sites of plaque formation and its progression may lead to stroke. However, little is known about hemodynamics and WSS distributions in the LCA. The purpose of this work is to set up a method to evaluate flow patterns and WSS distributions in the human LCA based on real patient-specific geometries reconstructed from medical images. A three-dimensional model of the LCA of a healthy patient was reconstructed based on a computer tomography (CT) study. A finite element volume mesh was constructed and blood flow trough it was modeled with the finite element method. WSS distribution was computed with later postprocessing. Results showed that the particular details of the geometry such as curvatures and branching produced flow disturbances and determined in last the WSS distribution. Specific regions of low WSS values were determined. This work shows the feasibility of developing a patient-specific method for evaluating flow pattern and WSS distributions in order to study atherosclerotic plaque formation in the human LCA with real geometries obtained from CT images processing.