Fluid structure interaction study of stenosed carotid artery considering the effects of blood pressure

Abstract

Atherosclerosis is the most common Cardiovascular Disease (CVD) causing increased morbidity. Although atherosclerosis is a general disease involving several factors, it preferentially affects the wall of the vessel bifurcations. The employment of advanced Computational Fluid Dynamics (CFD) has the potential in shedding more light in the further understanding of the causes of the diseases and perhaps aid in the early diagnosis. In this study, a three-dimensional Fluid Structure Interaction (FSI) study was carried out for a patient specific carotid. By considering physiological conditions, first normal and then with hypertension disease, hemodynamic parameters are evaluated to better understand the genesis and progress of atherosclerotic plaques in the carotid artery bifurcation. Two-way FSI was performed by applying a fully implicit second-order backward Euler differencing scheme using commercial code ANSYS and ANSYS CFX (version 19.0). Arbitrary Lagrangian-Eulerian (ALE) formulation is employed to calculate the arterial response by using the temporal blood response. Due to arterial bifurcation, obvious velocity reduction and backflow formation is observed which decrease shear stress and made it oscillatory at the starting point of the internal carotid artery near the carotid sinus, which resulted in low shear stress. Oscillatory shear index (OSI) signifies oscillatory behavior wall shear stress. By using the anatomically realistic 3D geometry and representative physiological conditions, the results obtained for shear stress are more acceptable. Comparing the results of this study with available literature shows that the regions with low wall shear stress and with OSI value more than 0.3 face potential risk to the plaque development. It is observed that hemodynamics of carotid artery is very much affected by the geometry and flow conditions and relatively low wall shear stress regions were observed post stenosis, which is a known reason for plaque development and progression.

Fluid Structure Interaction Study of Stenosed Carotid Artery Considering the Effects of Blood Pressure and Altered Gravity

“…In medium and smaller arteries, non-Newtonian assumption is valid as shear rate is lower than 100 s À1 and shear stresses depend non-linearly on the deformation rate [24]. A time varying velocity pulse is applied at inlet of both the carotid cases based on available literature [8]. A typical inlet velocity profile as shown in the Figure 4 is applied for both cases (a) and (b) without altered gravity behavior which contributes to sleeping posture.…”

“…It was observed that hemodynamics of the carotid artery was very much affected by the geometry and flow conditions. Furthermore, regions of relatively low wall shear stress were observed post stenosis, which is a known cause of plaque development and progression [8].…”

Effect of dome size on flow dynamics in saccular aneurysms – A numerical study

“…Grid independence test carried out for all aneurysm models adopted in the CFD study to optimise the element size for every aneurysm model and it is shown in Figure 3. A laminar flow model was used to simulate the steady flow in the carotid arteries with an RMS value of 10 -4 [27]. A maximum of 600 iterations was taken for convergence in the study.…”

Study on the Design and Optimization of a Portable Monitoring and Auxiliary Treatment Device for Upper Extremity Lymphedema–Focus on the Rehabilitation Function of the Device

“…The simulation of the upper arm low-ductility massage belt B and the forearm low-ductility massage belt B is carried out to improve the parameter design and optimization of the total rehabilitation module of the device. As an excellent finite element analysis software, ANSYS has been more and more used in biological simulation experiments ( Nowak et al, 2019 ; Aubert et al, 2020 ; Kumar et al, 2020 ). According to the biological structure of human upper limb, a 3D reconstruction of an upper limb model was carried out, and the simulation results were output by ANSYS software.…”