Comparison of the plaque rupture risk in different double-stenosis arrangements of coronary arteries by modeling fluid-structure interaction

Recent observations have shown that artery stenosis occurs as multiple-stenosis in 70% of patients with atherosclerosis plaques. Accordingly, the frequent occurrence of double-stenosis in blood arteries has inspired this paper to investigate and compare the plaque rupture risk in different arrangements of common plaque shapes in a double-stenosis. The plaque von-Mises stress in plaque fibrous cap is calculated by finite element modeling of the fluid-structure interaction (FSI) between the blood flow, artery and plaque components. Arbitrary Lagrangian-Eulerian approach is employed for FSI simulations and a benchmark problem dealing with wave propagation in a fluid-filled elastic tube is used for model verification. Transient velocity and pressure conditions of actual pulsatile blood flow through coronary artery are prescribed. The blood is assumed to be a Newtonian fluid and hyper-elastic material model is employed for describing nonlinear behavior of the human tissue composed of the arterial wall, lipid core and fibrous cap. It was observed that the arrangement composed of two diffused plaques is subjected to the maximum von-Mises stress, while the arrangement of ascending-descending plaques experiences the minimum von-Mises stress. The effect of different parameters such as the stenosis degree, the space length between the plaques, and the plaque length is studied and discussed.