Investigating the Parameters of Blood Flow Resulting from the Unilateral Occlusion of the Renal Artery and Branches Area

Renal artery stenosis is a major cause of death and permanent harm to the body. The rigidness of the wall of the arteries is the main cause of atherosclerosis and renal artery stenosis. Therefore, the purpose of this study was to evaluate the effect of vessel wall thickening and renal artery stenosis on the entrance of blood flow through the arterioles of the kidney by using physical modeling, second goal of this study was to evaluate the effect of renal artery stenosis on the characteristics of the flow in the downstream and also to identify areas prone to congestion in the presence of renal artery stenosis. Actual geometry and boundary conditions was used for modeling. In this study, Newtonian and non-Newtonian models was assumed for the viscosity of blood and the results were compared to each other. The effect of mild (30%), moderate (50%) and severe (70%) occlusions was studied on the flow parameters. The areas which were prone to congestion were identified in occluded and non-occluded geometries and the results were compared. The results show that not much difference between Newtonian and non-Newtonian models for blood viscosity is noticed in the present geometry and blood can be considered as a Newtonian fluid. Investigation showed that the congestion-prone areas are located before and also in the first branch of bifurcation because in these areas the shear stress is maximum. The congestions haven’t influenced areas which were prone to occlusion, but the more percentage of stenosis the more there is possibility for occlusion.