The Geometric Effects on the Stress of Arterial Atherosclerotic Plaques: A Computational Study

Background: The rupture of atherosclerotic plaques could cause serious clinical events. The wall shear stress (WSS) and axial plaque stress (APS) could reflect the risk of plaque rupture. This study aimed to quantitatively investigate the geometric effects on WSS and APS using computational fluid dynamics (CFD).Methods: 63 plaque models were developed from three severities (75%, 82%, and 89% in area), three eccentricities (the deviation of plaque throat from the arterial centerline: 0, 0.375 and 0.75mm), and 7 different length combinations of the proximal and distal stenotic segments (2mm-5mm, 3mm-5mm, 4mm-5mm, 5mm-5mm, 5mm-4mm, 5mm-3mm, 5mm-2mm). For each model, CFD simulation was performed to calculate the maximum and area-averaged WSS and APS on the proximal and distal stenotic segments. The multivariate analysis of variance and linear regression analysis were performed to quantitatively investigate the geometry-stress relationship.The results showed that, the severity and eccentricity of a plaque were linearly related to its WSS and APS. APS value on a segment (proximal or distal) of the plaque depended on the segmental length It was also shown that the difference of APS between proximal and distal segments depended exclusively on the difference of length between segments (all p<0.05).Conclusion: The geometry of a plaque influences its WSS and APS. APS and its proximal/distal difference depend on the segmental lengths.