High Wall Shear Stress and Positive Wall Shear Stress Gradient Trigger the Initiation of Intracranial Aneurysms

2009 ◽  
Author(s):  
Eleni Metaxa ◽  
Markus Tremmel ◽  
Jianping Xiang ◽  
John Kolega ◽  
Max Mandelbaum ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Intracranial Aneurysms ◽  
Potential Role ◽  
Stress Gradient ◽  
Local Flow ◽  
High Wall Shear Stress ◽  
Wall Shear Stress Gradient ◽  
Wall Shear

While the pathogenesis of an intracranial aneurysm (IA) is poorly understood, it has been generally postulated to be related to hemodynamic insult. IAs are predominantly located at apices of arterial bifurcations or outer curves on or near the Circle of Willis, suggesting a potential role of the specific hemodynamics at such locations characterized by high wall shear stress (WSS). Clinically, new IA formation has been observed following local flow increase.

scholarly journals Hemodynamics of Cerebral Aneurysm Initiation: The Role of Wall Shear Stress and Spatial Wall Shear Stress Gradient

2011 ◽  
Vol 32 (3) ◽  
pp. 587-594 ◽  
Author(s):  
Z. Kulcsár ◽  
Á. Ugron ◽  
M. Marosfői ◽  
Z. Berentei ◽  
G. Paál ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Cerebral Aneurysm ◽  
Stress Gradient ◽  
Wall Shear Stress Gradient ◽  
Shear Stress Gradient ◽  
Wall Shear

Numerical Investigation and Prediction of Atherogenic Sites in Branching Arteries

1995 ◽  
Vol 117 (3) ◽  
pp. 350-357 ◽  
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.

scholarly journals Modulating wall shear stress gradient via equilateral triangular channel for in situ cellular adhesion assay

2016 ◽  
Vol 10 (5) ◽  
pp. 054119 ◽  
Author(s):  
Hyung Woo Kim ◽  
Seonjin Han ◽  
Wonkyoung Kim ◽  
Jiwon Lim ◽  
Dong Sung Kim
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Stress Gradient ◽  
Cellular Adhesion ◽  
Adhesion Assay ◽  
Triangular Channel ◽  
Wall Shear Stress Gradient ◽  
Shear Stress Gradient ◽  
Wall Shear

Early Cellular and Molecular Changes During Hemodynamic Initiation of Intracranial Aneurysms in a Rabbit Model

2010 ◽  
Author(s):  
Ling Gao ◽  
Max Mandelbaum ◽  
Nicholas Liaw ◽  
Sabareesh K. Natarajan ◽  
J. Mocco ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Intracranial Aneurysms ◽  
Molecular Mechanisms ◽  
Morphological Changes ◽  
Stress Gradient ◽  
Rabbit Model ◽  
Apical Region ◽  
Apical Side ◽  
Wall Shear

Hemodynamics constitutes a critical factor in the formation of intracranial aneurysms. However, little is known about how an intracranial arterial wall responds to a hemodynamic insult, and how that response contributes to aneurysm formation. Unlike straight arterial segments (which respond to increased flow by expansive remodeling) and sinuses opposing bifurcation apices (which harbor recirculation flows and are prone to atherosclerotic development), aneurysmal degeneration occurs on the apical side of the bifurcation in the immediate peri-apical region, where flow creates very high wall shear stress (WSS) and wall shear stress gradient (WSSG)1. This results in destructive aneurysmal remodeling, characterized by loss of the internal elastic lamina (IEL) and thinning of the media. It is unknown how the unique hemodynamic conditions of combined high WSS and positive WSSG elicit these morphological changes, how the vascular wall responds to such insult at the molecular level, and what molecular mechanisms are involved.

scholarly journals Pulsatile Wall Shear Stress Gradient and Aortoseptal Angle: Implications for Subaortic Stenosis † 147

1997 ◽  
Vol 41 ◽  
pp. 27-27
Author(s):  
Michael D. VanAuker ◽  
Theresa A. Tacy ◽  
Gunnlaugur Sigfusson ◽  
Pedro J. Del Nido ◽  
Edward G. Cape
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Stress Gradient ◽  
Subaortic Stenosis ◽  
Wall Shear Stress Gradient ◽  
Shear Stress Gradient ◽  
Wall Shear

Intracranial Aneurysms Occur More Frequently at Bifurcation Sites That Typically Experience Higher Hemodynamic Stresses

Neurosurgery ◽  
2013 ◽  
Vol 73 (3) ◽  
pp. 497-505 ◽  
Author(s):  
Jaclyn M. Alfano ◽  
John Kolega ◽  
Sabareesh K. Natarajan ◽  
Jianping Xiang ◽  
Rocco A. Paluch ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Intracranial Aneurysms ◽  
Stress Gradient ◽  
Spatial Gradient ◽  
Impact Zone ◽  
Wall Shear ◽  
A Site ◽  
The Impact ◽  
Hemodynamic Stresses

Abstract BACKGROUND: Intracranial aneurysms (IAs) occur more frequently at certain bifurcations than at others. Hemodynamic stress, which promotes aneurysm formation in animal models, also differs among bifurcations, depending on flow and vessel geometry. OBJECTIVE: To determine whether locations that are more likely to develop IAs experience different hemodynamic stresses that might contribute to higher IA susceptibility. METHODS: We characterized the hemodynamic microenvironment at 10 sites in or around the circle of Willis where IAs commonly occur and examined statistical relationships between hemodynamic factors and the tendency for a site to form IAs. The tendency for each site to develop IAs was quantified on the basis of the site distribution from systematic literature analysis of 19 reports including 26 418 aneurysms. Hemodynamic parameters for these sites were derived from image-based computational fluid dynamics of 114 cerebral bifurcations from 31 individuals. Wall shear stress and its spatial gradient were calculated in the impact zone surrounding the bifurcation apex. Linear and exponential regression analyses evaluated correlations between the tendency for IA formation and the typical hemodynamics of a site. RESULTS: IA susceptibility significantly correlated with the magnitudes of wall shear stress and positive wall shear stress gradient within the hemodynamic impact zone calculated for each site. CONCLUSION: IAs occur more frequently at cerebral bifurcations that typically experience higher hemodynamic shear stress and stronger flow acceleration, conditions previously shown to promote aneurysm initiation in animals.

Wall shear stress gradient topography in the normal left coronary arterial tree: possible implications for atherogenesis

2004 ◽  
Vol 20 (5) ◽  
pp. 587-596 ◽  
Author(s):  
Thomas M. Farmakis ◽  
Johannes V. Soulis ◽  
George D. Giannoglou ◽  
George J. Zioupos ◽  
George E. Louridas
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Stress Gradient ◽  
Arterial Tree ◽  
Wall Shear Stress Gradient ◽  
Shear Stress Gradient ◽  
Wall Shear
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