Impact of non-Newtonian blood rheology on hemodynamics in a realistic coronary artery: A computational fluid dynamics study

Myocardial infarction is among the leading causes of death worldwide. Additionally, coronary artery disease is the primary culprit behind most heart attacks. This condition arises and progresses due to stresses in the arterial wall. Unlike previous studies, this work employs a highly realistic left coronary artery (LCA) geometry and directly compares quantitative outcomes across three distinct blood rheology models: (1) Newtonian, (2) Power-law, and (3) Carreau models. At the inlet and outlet, we used the actual blood pressure values, and on the walls, the no-slip condition was applied. The effects of non-Newtonian rheology are systematically mapped to clinically relevant hemodynamic indices, providing insight for this specific coronary geometry into the interplay between blood viscosity, artery curvature, and wall shear stress. Quantitative comparisons were conducted in terms of velocity distribution, wall shear stress (WSS), apparent viscosity, and pressure drop along the artery. The results show that non-Newtonian rheology significantly alters local hemodynamic behavior, particularly in regions of curvature and diameter variation. The total pressure drop across the artery was predicted as 1216.21 Pa for the Newtonian model, 1223.05 Pa for the Carreau model, and 1184.36 Pa for the Power-law model. Non-Newtonian models exhibited shear thinning behavior, leading to reduced apparent viscosity at elevated shear rates and noticeable deviations in velocity and WSS distributions compared with the Newtonian assumption. Low wall shear stress is established as the primary pathogenic factor in early-stage atherosclerosis development.