CFD STUDY OF BLOOD FLOW AROUND PLAQUES OF DIFFERENT SHAPES IN HUMAN CAROTID ARTERY

Abstract

Stroke is the second major cause of death worldwide after coronary heart disease. Due to fatty deposits plaques develop in arteries. These plaques offer resistance to the blood flow thus changing the flow characteristics in the blood vessels. Plaques in carotid artery cause reduced blood supply to brain which may lead to stroke. Despite dramatic advances made both in diagnostic measures (like Computed Tomography (CT) scan and Magnetic Resonance Imaging (MRI)) and in therapeutic practices for vascular diseases in recent years, on average, one person suffers a stroke every 40 seconds and one dies of a stroke every 3 to 4 minutes. The aim of this research is to investigate the effect of plaque shape on blood flow through the carotid artery leading to plaque growth and rupture. For this purpose three plaque shapes were considered; trapezoidal, elliptical and triangular with same base and height measurements, thus imposing same area reduction of 30% in artery. A carotid artery model based on statistical analysis called tuning fork model was constructed. Various Computational Fluid Dynamics (CFD) simulations were performed to analyze the effect of different plaque shapes on blood flow. Comparison of simulation results for the three plaque shapes showed that trapezoidal shape has more effect on blood flow producing highest flow velocities and wall shear stresses. This fact indicates that plaques similar to trapezoidal shape may be more prone to rupture. It was also found that trapezoidal plaques created lowest wall shear stress region downstream of the plaque which may increase the fatty deposits in that area. The study suggests that patients with such plaques should be considered for surgery at an early stage of atherosclerosis to avoid cardiovascular complications. Recognising the features that contribute to this increased vulnerability may help clinicians make early interventions in patients with plaques that are prone to rupture, thus mitigating the stroke chances and remarkably increasing the survival rate and quality of life of such patients.