Effects of longitudinal asymmetric distribution of a lipid core on plaque wall stress

The rupture of the atherosclerotic plaque is related to the mechanical stress and structural integrity of plaque wall tissues. In order to investigate the longitudinal asymmetry across the stenosis of the arterial plaque wall, asymmetric plaque wall models were constructed by skewing the lipid core distribution in the upstream direction. Wall stress and blood flow in the coronary artery models were computationally analyzed considering fluid and structure interaction. The values of maximum cap stress increased, and its location moved toward the proximal cap as asymmetry increased. Hemodynamic wall shear stress (WSS) did not change much owing to negligible changes in luminal geometry, but the maximum WSS and the spatial gradient of WSS were higher in the asymmetry models than in the symmetry model. The pressure drop and pressure gradient across the stenosis were also higher in the asymmetry models. Because higher peak wall stress, wall strain, increased WSS, WSS gradient, pressure drop, and pressure gradient are correlated with weakening and rupture of the plaque wall, we suspect that longitudinal asymmetric distribution of the lipid core in the plaque could affect plaque wall stability and vulnerability.