Hemodynamics of plaque eccentricity in a compliant left coronary bifurcation: Focus on the left anterior descending artery

Plaque eccentricity significantly influences the onset and progression of coronary artery disease. Studies indicate that the left coronary artery branches are more prone to atherosclerosis and related heart conditions than their right counterparts, particularly the left anterior descending (LAD) branch. Although arterial compliance influences the hemodynamics of eccentric plaques, few studies have examined it using flexible artery models. This study fills that gap through a two-way fluid–structure interaction analysis on a hyperelastic arterial-wall model. First, the most perilous eccentricity type—based on the direction of plaque shift—is identified in the LAD with moderate (50%) stenosis. Then, the effects of varying degrees of eccentricity (DOEs) are examined for this vulnerable type of eccentricity shift. Results reveal that eccentricity directed from the myocardial wall (MW) to the epicardial wall (EW) poses the highest risk. As DOE increases from 0% to 100%, atheroprone areas on post-stenotic regions expand on the MW and shrink on the pre-stenotic region on the MW, besides both pre- and post-stenotic regions on the EW, indicating that the MW is more vulnerable. Overall, atheroprone areas in terms of low time-averaged wall shear stress (≤0.4 Pa) grow from 2.20% to 3.90%, high oscillatory shear index (≥0.3) expands from 0.53% to 1.05%, and elevated relative residence time (≥10 Pa−1) increases from 0.58% to 1.28% with the rise in DOE. These trends suggest increased disturbed flow and atherosclerosis risk with rising eccentricity. Concurrently, fractional flow reserve declines from 0.951 to 0.902, reflecting reduced vessel efficiency in maintaining normal blood flow.