Shah Mohammed Abdul Khader

Cardiovascular disease (CVD) is one major cause of morbidity caused by the progress of atherosclerosis without any symptoms and has a high risk of Transient Ischemic Stroke (TIS). The carotid bifurcation and bulb are the region where the blood flow is irregular, which may lead to the progression of the plague. The flow disruption due to stenosis in idealised carotid artery has been extensively investigated using Fluid Structure interaction (FSI). However, the haemodynamic of patient specific carotid artery has been intensively studied. In this study, a comparison of blood flow in healthy and stenosed (80% blockage in the carotid bulb region) was carried out using Two- way FSI analysis considering non-Newtonian blood viscosity and isotropic property for vessel wall. Haemodynamic parameters such as velocity streamline, pressure, vorticity, helicity, Time-Averaged Wall shear stress (TAWSS) and Oscillatory Shear Index (OSI) were analysed along with structural parameters such as wall displacement and von Mises stress. The comparison between healthy and stenosed arteries reveals that stenosis significantly increases the velocity magnitude due to the reduced flow area caused by plaque buildup. This narrowing also results in elevated pressure upstream of the stenosis. In both healthy and stenosed arteries, maximum deformation occurs near the bifurcation at the left and right lateral sections, with the highest von Mises Stress located near the internal wall of the flow divider. In stenosed arteries, the stress magnitude is six times higher than in healthy arteries, illustrating the profound effect stenosis has on haemodynamic. Overall, the analysis emphasizes how stenosis disrupts normal blood flow and alters bio-fluid dynamics in the carotid artery

The carotid artery is a clinically important site in the human circulatory system as the consequences of its disease results in adverse outcomes like ischemic strokes, or death for too prolonged ischemia. Understanding the hemodynamics of this artery and its bifurcation are important. A method of treating the stenosis of this artery is Carotid Angioplasty and Stenting (CAS). This procedure results in a heavily modified hemodynamics or state of flow. To understand and predict this flow field modification Computational Fluid Dynamics (CFD) is an important computational tool. Further, the presence of a stent would affect hemodynamics. The aim of this work is to study these effects in patient-specific cases. The reconstructed patient-specific models will form the basis of the construction of the post-stenting carotid bifurcation models. A transient analysis was carried out to estimate the time-varying parameters in the fluid domains over a cardiac cycle as well as to gauge time average values over a cardiac cycle. Results are obtained for hemodynamic parameters, like wall shear stress, velocity, pressure, vorticity, and helicity, in both the prepared stenosed and stented geometries. It is seen that the stenting procedure leads to the renewal of the CCA to ICA flow path. But simultaneously the region in which the stent is present becomes a region of low TAWSS and contains areas of high OSI. These areas of low TAWSS and high OSI within the stented portions of the carotid bifurcations are indications for regions of possible restenosis. Therefore, the investigation demonstrates the likely region for future plaque growth. Further, the effects of widening of the lumen are also noted in comparison to the pre-stent cases

Atherosclerosis is a condition of plaque/fatty deposit on the walls of the artery resulting in obstruction to blood flow. Several researchers have studied the hemodynamic behavior under resting condition on patient-specific models. The aim of present

Gravity associated with postural changes has a strong bearing on haemodynamics of blood flow in arteries. Its effect on stenosed cases has not been widely investigated. In the present study, variation observed in blood flow during postural changes is investigated for different conditions like standing, sleeping and head-down position. A fluid structure interaction study is carried out for idealized normal and 75 % eccentric and concentric stenosed common carotid normal artery. The results clearly indicate the effects of altered gravity on flow conditions. It was found to be very significant during head-down position and demonstrated very high arterial blood pressure in stenosed common carotid when compared with normal carotid.