Nonlinear biomechanics of bifurcated atherosclerotic coronary arteries

One of the most high-risk locations of plaque growth and rupture initiation (and hence occurrence of heart attack) is the first main bifurcation of the left main coronary artery; the aim of this investigation is to analyse the nonlinear three-dimensional biomechanics of bifurcated atherosclerotic left coronary artery. In order to examine the influence of different system parameters, a biomechanical model of a bifurcated coronary artery is developed. Three plaques of varying geometry and material properties inside the three branches of the left main (LM), the left anterior descending (LAD), and the left circumflex (LCx) are modelled incorporating three-dimensionality, nonlinear geometric and material properties, asymmetry, viscosity, and hyperelasticity, and fluid-solid interaction. A finite element method (FEM) is employed to incorporate all of the above-mentioned important features in addition to physiological blood pulsation, heart motion, active media layer contraction, lipid plaque, calcium deposition, three different artery layers, micro-calcification, and non-Newtonian model for blood. Moreover, the effects of different system features such as stenosis, curved shape of the artery, plaque location, and fibrous cap thickness on the stress field (shear and structural) are examined. The developed biomechanical model could be utilised to estimate the risk of the initiation of plaque rupture inside the human coronary artery and the occurrence of heart attack.