Effect of increased severity in patient specific stenosis of common carotid artery using CFD-a case study

The prevailing vascular fluid dynamics plays an important role in the development of atherosclerosis which is one of the most wide spread disease in humans. The recent advances in computational fluid dynamics (CFD) can be useful in observing the flow behavior downstream of the stenosis. The present study investigates a simple case of 66% eccentric stenosis of an approximate model generated from Doppler scan. The blood is assumed to be incompressible, homogenous and Newtonian, while artery is assumed to be a rigid wall. The transient analysis is performed using ANSYS-10.0, commercially available Finite Element Software. The flow pattern, Wall Shear Stress (WSS) and pressure contours are observed at pre-stenotic, throat and post-stenotic regions. In an attempt to predict the flow changes with varying the severity of stenosis, the percentage of stenosis is varied from 66% to 75%, 80%, 85%, 90%, 95% and analyzed. Comparison of results concludes that, with the increase in severity of stenosis, the flow changes abruptly causing an increase in velocity and WSS at throat region. The flow is highly turbulent in downstream leading to formation of eddies. The effect of back pressure is observed during late diastole which alters the flow behavior considerably in the downstream region.