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The high stresses on plaque wall experienced by stent implantation into a stenotic artery can go beyond the material strength of plaque tissue, potentially leading to plaque rupture. Two non-commercial stents with different link structures called S-type and N-type were taken into account, respectively. A non-linear finite element model was developed to investigate the influence of the stenosis level (i.e., 24%, 40%, and 50%) and arterial curvature radius (i.e., 6, 10, and 20mm) on the stress induced within the plaque tissue during stent expansion. The numerical results indicated that the severer stenosis level and more tortuous artery caused the higher stress on plaque wall. The maximal stresses on the plaque wall were in the fracture level of 1.79MPa for N-type stent, and 1.82MPa for S-type stent under the 50% stenosis rate and 6mm curvature radius. Due to smaller compliance mismatch to the curved vessel, the N-type stent was founded to induce less stress gradient on the plaque wall than that by the S-type stent. This suggests a lower risk of the plaque rupture for the N-type stent. This study showed how the arterial curvature radius and stenosis level were correlated with the plaque vulnerability. Therefore, it is possible to choose a suitable stent in terms of arterial stenosis geometry and thereby optimize the outcome of stenting procedure.

Atherosclerosis is a disease in which plaque builds up inside arteries. It is also considered as one of the most serious and common forms of cardiovascular disease which can lead to heart attack and stroke. In the current research, finite element method is used to anticipate plaque vulnerability based on peak plaque stress using human samples. A total of 23 healthy and atherosclerotic human coronary arteries, including 14 healthy and 9 atherosclerotic are removed within 5 h postmortem. The samples are mounted on a uniaxial tensile test machine and the obtained mechanical properties are used in finite element models. The results, including the Mooney–Rivlin hyperelastic constants of the samples as well as peak plaque stresses, are computed. It is demonstrated that the atherosclerotic human coronary arteries have significantly (p < 0.05) higher stiffness compared to healthy ones. The hypocellular plaque, in addition, has the highest stress values compared to the cellular and calcified ones and, consequently, is so prone to rupture. The calcified plaque type, nevertheless, has the lowest stress values and, remains stable. The results of this study can be used in the plaque vulnerability prediction and could have clinical implications for interventions and surgeries, such as balloon angioplasty, bypass and stenting.