Biomechanical stress profiling in coronary arteries via two-phase blood FSI.

This study focuses on the biomechanical stress determination of the left circumflex (LCx) coronary artery reconstructed based on in vivo angiography images via the development of a comprehensive biomechanical model incorporating a two-phase two-way coupled three-dimensional fluid-structure interaction (FSI). The blood flow is modelled as a two-phase pulsatile fluid, with 45% red blood cells and 55% plasma, and the artery wall is modelled as a soft viscohyperelastic material that is able to dynamically react to the blood-induced pressure. The flow characteristics, such as pressure, velocity, phase distribution, near-wall haemodynamic parameters, and flow-induced indices, are determined. The von Mises stress (VMS) and the deformation field of the arterial wall are also obtained. Comparing results based on the two-phase FSI model and those of a single-phase FSI show that taking into account the red blood cells alters the stresses, providing a better understanding of potential cardiovascular events. In all the cases investigated in this study, the wall shear stress (WSS) levels predicted by the two-phase FSI model are consistently lower than those obtained from the single-phase simulations. For example, at the location of maximum WSS during peak systole, the single-phase simulation employing the Quemada viscosity model predicts 143.43 Pa, whereas the single-phase simulation based on the power-law model predicts 39.85 Pa. In contrast, the two-phase model yields a substantially lower value of 24.79 Pa.