Influence of Intermittent Pneumatic Compression on Wall Shear Stress and Nitric Oxide Levels

Wall shear stress (WSS) in blood vessels has been shown to play an important role in the development of atherosclerosis. In particular, regions of low and oscillating WSS have been shown to correlate with the localization of atherosclerosis. Thus, we hypothesize that increasing the WSS for patients with peripheral vascular diseases (PVD) will either reduce PVD severity or slow its progression. We analyzed WSS changes from a study by Delis et al. on 32 limbs of PVD patients [1]. Results show that intermittent pneumatic compression (IPC) increases mean WSS by 170% and 240% in PVD patients and healthy subjects, respectively. Peak WSS was found to increase by 93% and 40% in PVD patients and healthy subjects, respectively. In addition, we examined changes in NOX level with use of IPC on five limbs from PVD patients. Our study demonstrated increased NOx levels in subjects after IPC. Further research is needed to determine the benefits of IPC for PVD patients.

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Numerical Investigation and Prediction of Atherogenic Sites in Branching Arteries

Journal of Biomechanical Engineering ◽

10.1115/1.2794191 ◽

1995 ◽

Vol 117 (3) ◽

pp. 350-357 ◽

Cited By ~ 84

Author(s):

M. Lei ◽

C. Kleinstreuer ◽

G. A. Truskey

Keyword(s):

Shear Stress ◽

Wall Shear Stress ◽

Blood Vessels ◽

Vector Fields ◽

Stress Gradient ◽

Western World ◽

Medium Size ◽

Wall Shear Stress Gradient ◽

Shear Stress Gradient ◽

Wall Shear

Atherosclerosis, a disease of large- and medium-size arteries, is the chief cause of death in the US and most of the western world. It is widely accepted that the focal nature of the disease in arterial bends, junctions, and bifurcations is directly related to locally abnormal hemodynamics, often labeled “disturbed flows.” Employing the aorto-celiac junction of rabbits as a representative atherosclerotic model and considering other branching blood vessels with their distinctive input wave forms, it is suggested that the local wall shear stress gradient (WSSG) is the single best indicator of nonuniform flow fields leading to atherogenesis. Alternative predictors of susceptible sites are briefly evaluated. The results discussed include transient velocity vector fields, wall shear stress gradient distributions, and a new dimensionless parameter for the prediction of the probable sites of stenotic developments in branching blood vessels. Some of the possible underlying biological aspects of atherogenesis due to locally significant |WSSG|-magnitudes are briefly discussed.

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Effects of stenoses on non-Newtonian flow of blood in blood vessels

International Journal of Biomathematics ◽

10.1142/s1793524515500102 ◽

2015 ◽

Vol 08 (01) ◽

pp. 1550010 ◽

Cited By ~ 12

Author(s):

Om Prakash ◽

O. D. Makinde ◽

S. P. Singh ◽

Nidhi Jain ◽

Devendra Kumar

Keyword(s):

Shear Stress ◽

Wall Shear Stress ◽

Blood Vessels ◽

Flow Rate ◽

Homogeneous Fluid ◽

Human Artery ◽

Bingham Plastic ◽

Uniform Cross Section ◽

Flow Through ◽

Wall Shear

In this paper, a mathematical model for steady blood flow through blood vessels with uniform cross-section in stenoses arteries has been proposed. Blood is assumed to be non-Newtonian, incompressible and homogeneous fluid. Blood in human artery is represented as Bingham plastic fluid. Expressions for flow rate, wall shear stress, and resistance to flow against stenoses size have been obtained. Obtained results indicate that stenoses size decreases the flow rate and increases the wall shear stress as well as resistance to flow.

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Analysis of complex flow and the relationship between blood pressure, wall shear stress, and intima-media thickness in the human carotid artery

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00989.2006 ◽

2007 ◽

Vol 293 (2) ◽

pp. H1031-H1037 ◽

Cited By ~ 61

Author(s):

A. D. Augst ◽

B. Ariff ◽

S. A. G. McG. Thom ◽

X. Y. Xu ◽

A. D. Hughes

Keyword(s):

Blood Pressure ◽

Shear Stress ◽

Carotid Artery ◽

Wall Shear Stress ◽

Healthy Subjects ◽

Systolic Pressure ◽

Intima Media Thickness ◽

Complex Flow ◽

Media Thickness ◽

Wall Shear

Background: Previous clinical studies have observed relationships between increased intima-media thickness (IMT) in the carotid artery, elevated blood pressure, and low wall shear stress (WSS) calculated from the Poiseuille equation. This study used numerical methods to more accurately determine WSS in the carotid artery and to investigate possible determinants of increased IMT. Methods: IMT [common carotid artery (CCA) and bulb], CCA flow velocity, brachial systolic (SBP) and diastolic blood pressure (DBP), and carotid systolic pressure (cSBP) were measured in 14 healthy subjects (aged 44 ± 16 yr). Flow patterns in the carotid bifurcation were determined by computational fluid dynamics (CFD) based on three-dimensional ultrasound geometry. Instantaneous and time-averaged wall shear stress (WSSav), oscillatory shear index (OSI), and wall shear stress angle gradients (WSSAG) were calculated. Results: IMT was positively related to SBP, DBP, cSBP, and WSSAG and inversely related to WSSav in the CCA. In the bulb, IMT was positively related to SBP and cSBP but was not significantly related to WSSav or WSSAG. IMT was unrelated to OSI in both the CCA and the bulb. Conclusion: Increased carotid artery IMT in healthy subjects with no evidence of focal plaques is primarily a response to elevated pressure.

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Effect of Wall Shear Stress on Abdominal Aortic Aneurysm Expansion: Study With Longitudinal Patient Images

ASME 2012 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2012-80350 ◽

2012 ◽

Author(s):

B. Zambrano ◽

A. Dupay ◽

F. Jaberi ◽

W. Lee ◽

S. Baek

Keyword(s):

Shear Stress ◽

Wall Shear Stress ◽

Open Surgery ◽

Vascular Diseases ◽

Aortic Aneurysms ◽

Maximum Diameter ◽

Abdominal Aortic ◽

Reduce Risk ◽

Wall Shear

Abdominal Aortic Aneurysms (AAA), a focal enlargement of abdominal aorta, is a form of vascular diseases that affects large part of the population. It can cause the mortality up to 90% of the cases when it ruptures. Currently, the best known treatment to reduce risk is open surgery or endovascular repair. Since the risk of such surgery repair is high, in most patients with AAAs< 55mm in its maximum diameter the surgical treatment is postponed. An effort to enhance the accuracy of the risk assessment and to prevent AAA’s growth and rupture is being made, but the mechanisms promoting AAAs growth are still largely unknown. AAAs can be affected by different factors, among those, hemodynamics is known to play important roles in AAA initiation and progression. Particularly, the wall shear stress is believed to contribute to AAA expansion and rupture. For the present study, we use geometries constructed from longitudinal CT images obtained during AAA follow-up studies and investigate relations between multiple hemodynamics factors with local expansion of AAAs.

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Fluid-structure interaction simulation of tissue degradation and its effects on intra-aneurysm hemodynamics

Biomechanics and Modeling in Mechanobiology ◽

10.1007/s10237-022-01556-7 ◽

2022 ◽

Author(s):

Haifeng Wang ◽

Klemens Uhlmann ◽

Vijay Vedula ◽

Daniel Balzani ◽

Fathollah Varnik

Keyword(s):

Shear Stress ◽

Wall Shear Stress ◽

Vascular Diseases ◽

Von Mises Stress ◽

Arterial Walls ◽

Tissue Degradation ◽

Blood Pressures ◽

Arterial Wall Mechanics ◽

Wall Shear ◽

Von Mises

AbstractTissue degradation plays a crucial role in vascular diseases such as atherosclerosis and aneurysms. Computational modeling of vascular hemodynamics incorporating both arterial wall mechanics and tissue degradation has been a challenging task. In this study, we propose a novel finite element method-based approach to model the microscopic degradation of arterial walls and its interaction with blood flow. The model is applied to study the combined effects of pulsatile flow and tissue degradation on the deformation and intra-aneurysm hemodynamics. Our computational analysis reveals that tissue degradation leads to a weakening of the aneurysmal wall, which manifests itself in a larger deformation and a smaller von Mises stress. Moreover, simulation results for different heart rates, blood pressures and aneurysm geometries indicate consistently that, upon tissue degradation, wall shear stress increases near the flow-impingement region and decreases away from it. These findings are discussed in the context of recent reports regarding the role of both high and low wall shear stress for the progression and rupture of aneurysms.

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Coronary Artery Stenting Affects Wall Shear Stress Topological Skeleton

Journal of Biomechanical Engineering ◽

10.1115/1.4053503 ◽

2022 ◽

Author(s):

Claudio Chiastra ◽

Valentina Mazzi ◽

Maurizio Lodi Rizzini ◽

Karol Calò ◽

Anna Corti ◽

...

Keyword(s):

Shear Stress ◽

Coronary Artery ◽

Wall Shear Stress ◽

Vascular Diseases ◽

Human Coronary Artery ◽

Term Outcome ◽

Clinical Images ◽

Long Term Outcome ◽

Wall Shear ◽

The Impact

Abstract Despite the important advancements in the stent technology for the treatment of diseased coronary arteries, major complications still affect the post-operative long-term outcome. The stent-induced flow disturbances, and especially the altered wall shear stress (WSS) profile at the strut level, play an important role in the pathophysiological mechanisms leading to stent thrombosis (ST) and in-stent restenosis (ISR). In this context, the analysis of the WSS topological skeleton is gaining more and more interest by extending the current understanding of the association between local hemodynamics and vascular diseases. The present study aims to analyze the impact that a deployed coronary stent has on the WSS topological skeleton. Computational fluid dynamics simulations were performed in three stented human coronary artery geometries reconstructed from clinical images. The selected cases presented stents with different designs (i.e., two contemporary drug eluting stents and one bioresorbable scaffold) and included regions with stent malapposition or overlapping. A recently proposed Eulerian-based approach was applied to analyze the WSS topological skeleton features. The results highlighted that the presence of single or multiple stents within a coronary artery markedly impacts the WSS topological skeleton. In particular, repetitive patterns of WSS divergence were observed at the luminal surface, highlighting a WSS contraction action proximal to the struts and a WSS expansion action distal to the struts. This WSS action pattern was independent from the stent design. In conclusions, these findings could contribute to a deeper understanding of the hemodynamic-driven processes underlying ST and ISR.

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Blood flow pattern and wall shear stress in the internal carotid arteries of healthy subjects

Acta Radiologica ◽

10.1080/02841850802068624 ◽

2008 ◽

Vol 49 (7) ◽

pp. 806-814 ◽

Cited By ~ 17

Author(s):

Binbin Sui ◽

Peiyi Gao ◽

Yan Lin ◽

Bing Gao ◽

Long Liu ◽

...

Keyword(s):

Blood Flow ◽

Shear Stress ◽

Wall Shear Stress ◽

Flow Pattern ◽

Healthy Subjects ◽

Carotid Arteries ◽

Internal Carotid ◽

Blood Flow Pattern ◽

Wall Shear ◽

Internal Carotid Arteries

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Wall shear stress computation for blood vessels and estimation by machine leaning

The Proceedings of The Computational Mechanics Conference ◽

10.1299/jsmecmd.2017.30.254 ◽

2017 ◽

Vol 2017.30 (0) ◽

pp. 254

Author(s):

Hiroshi SUITO ◽

Viet Q.H. HUYNH ◽

Kenji TAKIZAWA ◽

Takuya UEDA

Keyword(s):

Shear Stress ◽

Wall Shear Stress ◽

Blood Vessels ◽

Machine Leaning ◽

Stress Computation ◽

Wall Shear

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Regulation of flow and wall shear stress in arteriolar networks of the hamster cheek pouch

Journal of Applied Physiology ◽

10.1152/japplphysiol.00984.2001 ◽

2002 ◽

Vol 92 (5) ◽

pp. 2080-2088 ◽

Cited By ~ 7

Author(s):

Randall J. Fox ◽

Mary D. Frame

Keyword(s):

Nitric Oxide ◽

Shear Stress ◽

Wall Shear Stress ◽

Cheek Pouch ◽

Branch Points ◽

Hamster Cheek Pouch ◽

Pentobarbital Sodium ◽

Dilatory Response ◽

Wall Shear ◽

Diameter Change

Our purpose was to define arteriolar network hemodynamics during moderate increases in interstitial adenosine or nitric oxide in the hamster ( n = 34, pentobarbital sodium 70 mg/kg) cheek pouch tissue. The network consists of a feed arteriole (∼12-μm diameter, ∼800-μm length) with three to six branches. Observations of diameter, red blood cell flux, and velocity were obtained at the feed before the branch and within the branch. A comparison of baseline with suffused adenosine or sodium nitroprusside (SNP) 10−9 to 10−5 M showed the following. First, diameter change was heterogeneous by agonist, did not reflect the expected dilatory response, and was related to location within the network. With adenosine, upstream branch points constricted and those downstream dilated, even at 10−5 M. With SNP, upstream branch points dilated, whereas those downstream constricted. Second, with adenosine, changes in diameter, flux, and velocity together resulted in no change in wall shear stress until 10−5 M. Wall shear stress was not maintained at a constant level with N ω-nitro-l-arginine (10−5 M), suggesting a role for flow-dependent diameter changes with adenosine. With SNP, diameter change correlated with the baseline (before SNP) shear stress conditions.

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