Comparative analysis of stable and unstable plaques in the hemodynamic environment

Atherosclerotic plaques are the main cause of arterial stenosis. In this study, we construct stenosis models for both stable and unstable plaques, compare and analyze the hemodynamic impacts of these two plaques and explore their fatigue lifetimes at a 60% degree of stenosis. The assumptions of the idealized models and the fluid-structure interaction technique are used. The novelty of this work is to perform the stratified and refined simulation of atherosclerotic plaques. The results demonstrate that unstable plaque has a more pronounced pressure drop at the stenosis in contrast to stable plaque. It also exhibits a higher oscillatory shear index (OSI), a longer particle relative residence time (RRT), and a shorter fatigue life. The findings are that a thicker fibrous cap and a certain degree of calcification in the stable plaque can effectively carry the flow pressure and wall shear stress (WSS), thereby reducing the risk of plaque rupture. However, turbulence and flow separation phenomena are more likely to form in the unstable plaque model, with significant increases in instantaneous WSS, OSI and RRT. Thus, the integrity of the fiber cap structure is disrupted and the plaque structure is more fragile.