Advanced Computational Models for Disturbed and Turbulent Flow in Stenosed Human Carotid Artery Bifurcation

Tan, F. P. P.; Soloperto, Giulia; Wood, Nigel B.; Thom, Simon; Hughes, Alun D.; Xu, Xiao Yun

doi:10.1007/978-3-540-69139-6_99

Cited by 8 publications

(8 citation statements)

References 20 publications

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“…The carotid artery geometry was obtained from an MRI scan of a single patient with a mild stenosis at the location of the carotid sinus. 28 An unstructured tetrahedral mesh was generated with 53,000 nodes and 263,000 cells, which is shown in Fig. 11 a.…”

Section: Resultsmentioning

confidence: 99%

Computational Simulations of Magnetic Particle Capture in Arterial Flows

2009

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The aim of Magnetic Drug Targeting (MDT) is to concentrate drugs, attached to magnetic particles, in a specific part of the human body by applying a magnetic field. Computational simulations are performed of blood flow and magnetic particle motion in a left coronary artery and a carotid artery, using the properties of presently available magnetic carriers and strong superconducting magnets (up to B ≈ 2 T). For simple tube geometries it is deduced theoretically that the particle capture efficiency scales as \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\eta \sim \sqrt{{Mn}_{\rm p}}$$\end{document}, with Mnp the characteristic ratio of the particle magnetization force and the drag force. This relation is found to hold quite well for the carotid artery. For the coronary artery, the presence of side branches and domain curvature causes deviations from this scaling rule, viz. η ∼ Mnpβ, with β > 1/2. The simulations demonstrate that approximately a quarter of the inserted 4 μm particles can be captured from the bloodstream of the left coronary artery, when the magnet is placed at a distance of 4.25 cm. When the same magnet is placed at a distance of 1 cm from a carotid artery, almost all of the inserted 4 μm particles are captured. The performed simulations, therefore, reveal significant potential for the application of MDT to the treatment of atherosclerosis.

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Section: Resultsmentioning

confidence: 99%

Computational Simulations of Magnetic Particle Capture in Arterial Flows

2009

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“…The Womersley method was used to define the pulsatile velocity waveform [ 39 , 40 ] at the inlet of the computational domain. The transient and patient-specific inflow velocity waveform following [ 1 ] is illustrated in Figure 6 .…”

Section: Methodsmentioning

confidence: 99%

“…Narrowing of an arterial lumen tends to occur in regions of disturbed flow and oscillating wall shear stress (WSS). Tan et al [ 1 ] linked the growth, progression, and structure of plaque in a 70% carotid symmetric stenosis at rupture to the oscillating wall shear stresses using pulsatile transitional simulations. Considering axially asymmetric stenosis and Newtonian fluid model Gao et al [ 2 ] found that the Womersley number has a great influence on the vortex generation and the WSS distribution and to a lesser extent on the Reynolds number.…”

Section: Introductionmentioning

confidence: 99%

Simulations of Magnetohemodynamics in Stenosed Arteries in Diabetic or Anemic Models

Alshare

Tashtoush

2016

Computational and Mathematical Methods in Medicine

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Pulsatile flow simulations of non-Newtonian blood flow in an axisymmetric multistenosed artery, subjected to a static magnetic field, are performed using FLUENT. The influence of artery size and magnetic field intensity on transient wall shear stress, mean shear stress, and pressure drop is investigated. Three different types of blood, namely, healthy, diabetic, and anemic are considered. It is found that using Newtonian viscosity model of blood in contrast to Carreau model underestimates the pressure drop and wall shear stress by nearly 34% and 40%, respectively. In addition, it is found that using a magnetic field increases the pressure drop by 15%. Generally, doubling the artery diameter reduces the wall shear stress approximately by 1.6 times. Also increasing the stenosis level from moderate to severe results in reduction of the shear stress by 1.6 times. Furthermore, doubling the diameter of moderately stenosed artery results in nearly 3-fold decrease in pressure drop. It is also found that diabetic blood results in higher shear stress and greater pressure drop in comparison to healthy blood, whereas anemic blood has a decreasing effect on both wall shear stress and pressure drop in comparison to healthy blood.

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“…High shear stresses can cause damage to the endothelial layer of the wall, activation and aggregation of platelets, formation of thrombosis [8,9] and plaque rupture [10].…”

Section: Introductionmentioning

confidence: 99%

“…In present time most researchers considered low wall shear stress is directly associated with AD [3,4,[10][11][12][13]. Younis [14], notes that the wall shear stresses below 1.5 Pa stimulating atherogenic phenotype and is usually seen in areas prone to atherosclerotic deposits.…”

Section: Introductionmentioning

confidence: 99%

Biomechanical Bases of Forecasting Occurrence of Carotid Atherosclerosis

Kuzyk¹,

Ivanov²,

Dol³

2016

Ann Circ

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The purpose of this study was to investigate changes of the effective and shear stresses level on the surface of atherosclerotic plaques in comparison with the healthy vessel wall, as well as distribution of the hemodynamic forces. Two software modules were used: ANSYS CFX for simulating blood flow, and Structural (Mechanical) for simulating the stress-strain state of the walls. Geometric models of vessels were built on basis of healthy and diseased vessels casts in the CAD system SolidWorks. We discovered the phenomenon of stress-strain state of atherosclerotic plaques: soft plaque is different from the rigid, which creates conditions for plaque rupture under the influence of blood pressure and shear stress. The stress difference between rigid and unchanged vessel with carotid stenosis creates additional flows and vortexes, growing in proportion to the increase of the plaque size. In addition, such state can be directly related to the development of mural thrombosis. Analysis of the blood flow velocities vector field and pattern of streamlines in the external carotid artery demonstrates a complete blockage of the vessel. Vortex and congestion area formation in the ampoule of internal carotid artery creates conditions for further plaque progression.on the vessel, causing the weakening of the wall and subsequent development of atherosclerotic deposits. Therefore, this area of the carotid bifurcation has the tendency to AD and different proliferative processes development. On the contrary, the inner wall of the carotid bifurcation has a higher wall shear stress and the blood flow is unidirectional, and so at this location there is less intimal thickening and atherosclerotic plaques (AP) appearing. Thus, proliferating intimal thickening developing focally in those areas where the geometric features change the blood flow to reduce wall shear stress. Tang [9], concluded that both low and high shear stresses lead to the formation of thrombosis. There is an opinion [16], that AD arises because of fatigue in the areas of stress concentration. It is assumed that the AD localization explained by changes in the wall shear stresses and equivalent stress in the vessel wall [17,18].One can assume that the changes in the level of effective and shear stresses in conjunction with the level of oscillating stress may be used as a criterion for predicting the behaviour of different AP types. PurposeThe purpose of this study was to investigate changes of the effective and shear stresses level on the surface of atherosclerotic plaques in comparison with the healthy vessel wall, as well as distribution of the hemodynamic forces.

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Advanced Computational Models for Disturbed and Turbulent Flow in Stenosed Human Carotid Artery Bifurcation

Cited by 8 publications

References 20 publications

Computational Simulations of Magnetic Particle Capture in Arterial Flows

Computational Simulations of Magnetic Particle Capture in Arterial Flows

Simulations of Magnetohemodynamics in Stenosed Arteries in Diabetic or Anemic Models

Biomechanical Bases of Forecasting Occurrence of Carotid Atherosclerosis

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