A THRESHOLD BASED APPROACH TO ATHEROSCLEROTIC PLAQUE GROWTH
Zi Hui Foo, Yier Li, Satish Kumar Panda, Martin Buis
National University of Singapore, Singapore
Atherosclerosis is the leading cause of mortality in the world. It is a vascular disease caused by the inflammation of the arterial wall, which results in the accumulation of low-density lipoprotein (LDL) particles, monocytes, and foam cells at the site of inflammation. The development of the disease, and in particular the influence of LDL concentration on the growth of atherosclerotic plaques, is still a poorly understood phenomenon. Here we apply a threshold based approach to describe the growth of an atherosclerotic plaque. The immersed boundary-lattice Boltzmann method was used to simulate the physics of the fluid flow and fluid structure interactions on a simplified two-dimensional non-axisymmetrically stenosed arterial geometry. This model uses the Navier-Stokes equations and Darcy’s law as governing equations for the fluid dynamics, and convection-diffusion equations for modelling the mass balance in the lumen and intima. As the immersed boundary method permits the adjustment of boundary morphology during the solving process, the arterial wall is reshaped progressively according to local LDL concentration at the arterial wall. The simulation results indicated that the accumulation of LDL particles in the recirculation zone downstream of the plaque presents the conditions necessary for plaque growth initiation. The growth of the plaque causes the recirculation zone to shrink in size, resulting in a reduction in the rate of plaque growth as the local accumulation of LDL is reduced. The results show that the model is able to qualitatively capture the development of an atherosclerotic plaque with surface irregularities.