Abstract
Rupture of atherosclerotic plaque causes serious results. Since heterogeneity of the mechanical properties causes stress concentration which results in material failure, a local plaque volume was compared with local strain in circumferential direction. Rabbit thoracic aortas with atherosclerosis were excised and four needles were stuck into them at equal intervals on their circumference. From the movement of the needles during pressurization of the specimen, local circumferential lengths were calculated. Local circumferential strains were calculated by referring to the circumferential lengths at the stress-free state. Pressure strain elastic modulus Ep, stiffness parameter β, and incremental elastic modulus Einc were calculated. Total thickness Ttotal, plaque thickness Tplaque, medial wall thickness Twall, and area fraction of plaque Aplaque were also measured in histological sections. Einc and β obtained in the present study were comparable to those of the previous studies. Local strain at 80 mmHg ε80 correlated significantly with Twall (r = 0.37,p< 0.05) and Ttotal (r = 0.36,p< 0.05) while ε80 had insignificant correlation with Tplaque and Aplaque. These results indicate that atherosclerotic plaque has insignificant effects to their mechanical properties, and Twall becomes more uniform at physiological state than at the stress-free state.
