scholarly journals In vivo three-dimensional MR wall shear stress estimation in ascending aortic dilatation

2011 ◽  
Vol 33 (3) ◽  
pp. 589-597 ◽  
Author(s):  
Erik T. Bieging ◽  
Alex Frydrychowicz ◽  
Andrew Wentland ◽  
Benjamin R. Landgraf ◽  
Kevin M. Johnson ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Three Dimensional ◽  
Aortic Dilatation ◽  
Stress Estimation ◽  
Wall Shear

Inflammatory Response of Endothelial Cells to Wall Shear Stress in Three Dimensional Stenotic Models

2009 ◽  
Author(s):  
Leonie Rouleau ◽  
Joanna Rossi ◽  
Jean-Claude Tardif ◽  
Rosaire Mongrain ◽  
Richard L. Leask
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Three Dimensional ◽  
Realistic Model ◽  
In Vitro Models ◽  
Steady Flows ◽  
Wall Shear

Endothelial cells (ECs) are believed to respond differentially to hemodynamic forces in the vascular tree. Once atherosclerotic plaque has formed in a vessel, the obstruction creates complex spatial gradients in wall shear stress (WSS). In vitro models have used mostly unrealistic and simplified geometries, which cannot reproduce accurately physiological conditions. The objective of this study was to expose ECs to the complex WSS pattern created by an asymmetric stenosis. Endothelial cells were grown and exposed for different times to physiological steady flows in straight dynamic controls and in idealized asymmetric stenosis models. Cell morphology was noticeably different in the regions with spatial WSS gradients, being more randomly oriented and of cobblestone shape. Inflammatory molecule expression was also altered by exposure to shear and endothelial nitric oxide synthase (eNOS) was upregulated by its presence. A regional response in terms of inflammation was observed through confocal microscopy. This work provides a more realistic model to study endothelial cell response to spatial and temporal WSS gradients that are present in vivo and is an important advancement towards a better understanding of the mechanisms involved in coronary artery disease.

scholarly journals Measurements of the wall shear stress distribution in the outflow tract of an embryonic chicken heart

2009 ◽  
Vol 7 (42) ◽  
pp. 91-103 ◽  
Author(s):  
C. Poelma ◽  
K. Van der Heiden ◽  
B. P. Hierck ◽  
R. E. Poelmann ◽  
J. Westerweel
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Three Dimensional ◽  
Outflow Tract ◽  
Chicken Heart ◽  
Embryonic Chicken ◽  
Dimensional Reconstruction ◽  
Wall Shear ◽  
Embryo Heart

In order to study the role of blood–tissue interaction in the developing chicken embryo heart, detailed information about the haemodynamic forces is needed. In this study, we present the first in vivo measurements of the three-dimensional distribution of wall shear stress (WSS) in the outflow tract (OFT) of an embryonic chicken heart. The data are obtained in a two-step process: first, the three-dimensional flow fields are measured during the cardiac cycle using scanning microscopic particle image velocimetry; second, the location of the wall and the WSS are determined by post-processing flow velocity data (finding velocity gradients at locations where the flow approaches zero). The results are a three-dimensional reconstruction of the geometry, with a spatial resolution of 15–20 µm, and provides detailed information about the WSS in the OFT. The most significant error is the location of the wall, which results in an estimate of the uncertainty in the WSS values of 20 per cent.

Alterations in wall shear stress predict sites of neointimal hyperplasia after stent implantation in rabbit iliac arteries

2005 ◽  
Vol 288 (5) ◽  
pp. H2465-H2475 ◽  
Author(s):  
John F. LaDisa ◽  
Lars. E. Olson ◽  
Robert C. Molthen ◽  
Douglas A. Hettrick ◽  
Phillip F. Pratt ◽  
...  
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Iliac Artery ◽  
Stent Implantation ◽  
Neointimal Hyperplasia ◽  
Three Dimensional ◽  
Iliac Arteries ◽  
Wall Shear

Restenosis resulting from neointimal hyperplasia (NH) limits the effectiveness of intravascular stents. Rates of restenosis vary with stent geometry, but whether stents affect spatial and temporal distributions of wall shear stress (WSS) in vivo is unknown. We tested the hypothesis that alterations in spatial WSS after stent implantation predict sites of NH in rabbit iliac arteries. Antegrade iliac artery stent implantation was performed under angiography, and blood flow was measured before casting 14 or 21 days after implantation. Iliac artery blood flow domains were obtained from three-dimensional microfocal X-ray computed tomography imaging and reconstruction of the arterial casts. Indexes of WSS were determined using three-dimensional computational fluid dynamics. Vascular histology was unchanged proximal and distal to the stent. Time-dependent NH was localized within the stented region and was greatest in regions exposed to low WSS and acute elevations in spatial WSS gradients. The lowest values of WSS spatially localized to the stented area of a theoretical artery progressively increased after 14 and 21 days as NH occurred within these regions. This NH abolished spatial disparity in distributions of WSS. The results suggest that stents may introduce spatial alterations in WSS that modulate NH in vivo.

scholarly journals Bicuspid Aortic Cusp Fusion Morphology Alters Aortic Three-Dimensional Outflow Patterns, Wall Shear Stress, and Expression of Aortopathy

Circulation ◽  
2014 ◽  
Vol 129 (6) ◽  
pp. 673-682 ◽  
Author(s):  
Riti Mahadevia ◽  
Alex J. Barker ◽  
Susanne Schnell ◽  
Pegah Entezari ◽  
Preeti Kansal ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Three Dimensional ◽  
Aortic Cusp ◽  
Wall Shear

scholarly journals An In Vivo Murine Model of Low-Magnitude Oscillatory Wall Shear Stress to Address the Molecular Mechanisms of Mechanotransduction—Brief Report

2010 ◽  
Vol 30 (11) ◽  
pp. 2099-2102 ◽  
Author(s):  
Nick J. Willett ◽  
Robert C. Long ◽  
Kathryn Maiellaro-Rafferty ◽  
Roy L. Sutliff ◽  
Richard Shafer ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Murine Model ◽  
Molecular Mechanisms ◽  
Wall Shear ◽  
Low Magnitude
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