The present work is about the application of wall shear stress descriptors – time averaged wall shear stress (TAWSS), oscillating shear index (OSI) and relative residence time (RRT) – to the study of blood flow in the left coronary artery (LCA). These descriptors aid the prediction of disturbed flow conditions in the vessels and play a significant role in the detection of potential zones of atherosclerosis development. Hemodynamic descriptors data were obtained, numerically, through ANSYS® software, for the LCA of a patient-specific geometry and for a 3D idealized model. Comparing both cases, the results are coherent, in terms of location and magnitude. Low TAWSS, high OSI and high RRT values are observed in the bifurcation – potential zone of atherosclerosis appearance. The dissimilarities observed in the TAWSS values, considering blood as a Newtonian or non-Newtonian fluid, releases the importance of the correct blood rheologic caracterization. Moreover, for a higher Reynolds number, the TAWSS values decrease in the bifurcation and along the LAD branch, increasing the probability of plaques deposition. Furthermore, for a stenotic LCA model, very low TAWSS and high RRT values in front and behind the stenosis are observed, indicating the probable extension, in the flow direction, of the lesion.

The achievement of clinically viable methodologies to simulate the hemodynamics in patient-specific coronary arteries is still a major challenge. Therefore, the novelty of this work is attained by the introduction of the viscoelastic property of blood in the numerical simulations, to study the role of the left coronary artery (LCA) geometry configuration in the atherosusceptibility. Apparently healthy patients were used and four different methodologies were tested. The methodology giving the most accurate results at the same time of having the lowest computational time is the one considering the viscoelastic property of blood and computational fluid dynamics. A Pearson correlation analysis was used to highlight relationships between geometric configuration and hemodynamic descriptors based on the simulated wall shear stress (WSS). The left main stem (LMS) has the greatest atherosusceptibility followed by the left anterior descending artery (LAD) since the relative residence time (RRT) average values are 3.81 and 3.70 Pa⁻¹, respectively. The geometric parameters with relevant contribution to directional flow change are the cross-sectional areas, especially the one of LMS segment (A_LMS), and the curvature of LMS segment. For LMS and LAD segments, when A_LMS increases, blood flow disturbance (r = 0.81 in LMS and r = 0.74 in LAD) and atherosusceptibility (r = 0.84 in LMS and r = 0.85 in LAD) increases. When the LMS curvature decreases, the WSS magnitude (r = 0.80 in LMS and r = 0.83 in LAD) decreases, and disturbance (r=-0.80 in LMS and r=-0.91 in LAD) and atherosusceptibility (r=-0.74 in LMS and r=-0.74 in LAD) increases.