Simulation of atherosclerotic plaque impact on the red blood cells dynamics in arteries

Atherosclerosis, a coronary disease, is one of the main cause of mortality in the many countries. Atherosclerosis emerges as a results of  hardening and narrowing of the blood vessels , caused by the gradual accumulation of deposits on the inside of arteries walls. This finally leads to  atherosclerotic plaque. This plaque  consists of  fats, cholesterol, calcium deposits and other substances in the blood. If the formation of the plaque develops in such a way that interfere with the blood flow, the risk of heart attack and stroke increases. The fact is that the presence of deposits within the blood vessels affect the blood flow condition seriously and as a consequence the dynamics of RBCs which are suspended in the blood is influenced. In this work, The impact of atherosclerotic plaque on red blood cells (RBC) dynamics in the blood vessels is studied. To do so, a fluid-solid interaction (FSI) analysis is developed. For the fluid phase, a mesh-less Lagrangian method is adopted which is called smoothed particle hydrodynamics (SPH). RBCs are considered to be the solid phase and are assumed to behave like deformable solid floated in the blood. A network of springs and dampers are used in order to model the a deformable RBC.  A strong two way coupling is developed in the context of immersed boundary method (IBM) to capture the accurate fluid-solid interaction. The formation of atherosclerotic plaque manifest its effect  in the geometry of blood vessels as the  flow boundary conditions. Using purely Lagrangian methods for both fluid and solid is a beneficial strategy in terms of handling the complex boundary conditions as well as fluid-solid interface modeling.  It was found that the blood flow regime is significantly affected in the vicinity of the plaque  and hence the RBCs experience considerable deformation to accommodate to this  disturbance.  In case of large deformation,  the  chemical and biological function of RBCs is strongly influenced and finally it may contribute to further diseases.