Measurements of the wall shear stress distribution in the outflow tract of an embryonic chicken 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.

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In-vivo coronary flow profiling based on biplane angiograms: influence of geometric simplifications on the three-dimensional reconstruction and wall shear stress calculation

BioMedical Engineering OnLine ◽

10.1186/1475-925x-5-39 ◽

2006 ◽

Vol 5 (1) ◽

Cited By ~ 17

Author(s):

Ernst Wellnhofer ◽

Leonid Goubergrits ◽

Ulrich Kertzscher ◽

Klaus Affeld

Keyword(s):

Shear Stress ◽

Wall Shear Stress ◽

Coronary Flow ◽

Three Dimensional ◽

Three Dimensional Reconstruction ◽

Stress Calculation ◽

Dimensional Reconstruction ◽

Wall Shear

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

ASME 2009 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2009-206669 ◽

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.

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

Journal of Magnetic Resonance Imaging ◽

10.1002/jmri.22485 ◽

2011 ◽

Vol 33 (3) ◽

pp. 589-597 ◽

Cited By ~ 70

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

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

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.01107.2004 ◽

2005 ◽

Vol 288 (5) ◽

pp. H2465-H2475 ◽

Cited By ~ 107

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.

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