Vascular Wall Shear Stress in Clinical Practice

Pantos, John; Efstathopoulos, Efstathios; Katritsis, Demosthenes G.

doi:10.2174/157016107780368253

Cited by 17 publications

(15 citation statements)

References 72 publications

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“…This reinforces questions that have been raised about the reliability of clinical measurements of flow and wall shear rates, which tend to rely on simplistic assumptions about the velocity profile shape (Pantos et al ., 2007). For example, in Doppler ultrasound it is straightforward to measure, along the beam direction, the maximum blood velocity within a given artery cross-section.…”

Section: Discussionsupporting

confidence: 69%

“…Ultimately, such knowledge may help explain the common finding of eccentric wall thickening at the CCA (e.g. (Boussel et al ., 2007)), and also overcome errors in Doppler ultrasound estimations of flow and wall shear rates (e.g., Balbis et al ., 2005; Krams et al ., 2005) which typically rely on the assumption of fully-developed flow (Pantos et al ., 2007). Towards this ultimate end, the aim of the present study was to conduct the first thorough survey of the geometry of the human CCA from its thoracic origins to the level of the carotid bifurcation.…”

Section: Introductionmentioning

confidence: 99%

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On the shape of the common carotid artery with implications for blood velocity profiles

et al. 2011

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Clinical and engineering studies typically assume that the common carotid artery (CCA) is straight enough to assume fully developed flow, yet recent studies have demonstrated the presence of skewed velocity profiles. Towards elucidating the influence of mild vascular curvatures on blood flow patterns and atherosclerosis, the present study aimed to characterize the three-dimensional shape of the human CCA. The left and right carotid arteries of 28 participants (62±13 years) in the VALIDATE (Vascular Aging – The Link that Bridges Age to Atherosclerosis) study were digitally segmented from 3D contrast-enhanced magnetic resonance angiograms, from the aortic arch to the carotid bifurcation. Each CCA was divided into nominal cervical and thoracic segments, for which curvatures were estimated by least squares fitting of the respective centerlines to planar arcs. The cervical CCA had mean radius of curvature of 127 mm, corresponding to a mean lumen:curvature radius ratio of 1:50. The thoracic CCA was significantly more curved at 1:16, with the plane of curvature tilted by a mean angle of 25 degrees and rotated close to 90 degrees with respect to that of the cervical CCA. The left CCA was significantly longer and slightly more curved than the right CCA, and there was a weak but significant increase in CCA curvature with age. Computational fluid dynamic (CFD) simulations carried out for idealized CCA geometries derived from these and other measured geometric parameters demonstrated that mild cervical curvature is sufficient to prevent flow from fully developing, independent of the degree of thoracic curvature. These findings reinforce the idea that fully-developed flow may be the exception rather than the rule for the CCA, and perhaps other nominally long and straight vessels.

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Section: Discussionsupporting

confidence: 69%

Section: Introductionmentioning

confidence: 99%

On the shape of the common carotid artery with implications for blood velocity profiles

et al. 2011

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“…[23][24][25][26] In these geometrically predisposed locations, vessel wall shear stress is significantly lower in magnitude, and exhibits directional changes and flow separation, features absent from regions of the arterial tree that are generally spared from atherosclerosis. [25][26][27][28][29][30] Indeed, in the straight parts of the vascular system, the blood flow velocity profile exhibits a parabolic shape, with the velocity being maximum at the center of the vessel and zero at the vessel walls. Since wall shear stress is defined as the product of the dynamic blood viscosity and the rate of blood flow velocity change near the vessel wall (namely, the wall shear rate), 17 in the straight parts of the vascular system, wall shear stress is equal in all segments of the vessel wall.…”

Section: Discussionmentioning

confidence: 99%

Anatomic Characteristics of Culprit Sites in Acute Coronary Syndromes

Katritsis¹,

Efstathopoulos²,

Pantos³

et al. 2008

J Interven Cardiology

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“…during clinical measurements based on Doppler ultrasound, when estimating flow rate and WSS, therefore affecting the reliability of the clinical derivation of those variables. 3,35,36,39 The quantitative hemodynamic/geometric characterization highlights the complexity of the interactions between realistic vessel geometries and the flow patterns within. In idealized vascular geometries, the mechanisms by which vessel curvature and torsion affect blood flow patterns can be effectively represented by dimensionless quantities, i.e., the widely known Dean and Germano numbers.…”

Section: Cca3-cca11mentioning

confidence: 99%

An Insight into the Mechanistic Role of the Common Carotid Artery on the Hemodynamics at the Carotid Bifurcation

2014

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The rationale for this study lies in the well-known predilection for vascular disease of the carotid bifurcation, attributed to an altered shear stress distribution at the luminal surface and mitigated by helical fluid structures establishing inside the bifurcation. Here we investigate the mechanistic role played by the common carotid artery (CCA) in promoting complex intravascular flow and in influencing the hemodynamics at the distal carotid bifurcation. Fifty-five image-based computational hemodynamic models of eleven right carotid geometries were reconstructed from its brachiocephalic origin to above the bifurcation to assess how five different CCA reconstruction length affects intravascular fluid structures entering the bifurcation. A quantitative description of helical flow is adopted, in parallel to the description of disturbed shear at the bifurcation luminal surface. Our findings support the hypothesis that helical flow in CCA might reduce the likelihood of flow disturbances at the bifurcation. This confirms the physiological role of CCA in transporting and enforcing helical flow structures into the bifurcation, giving further contribution to the helicity-driven suppression of disturbed shear. A quantitative analysis of CCA geometry highlights the beneficial effect of proximal CCA curvature on helical flow and shows the complex interlacement among CCA geometry, helical flow, and disturbed shear at the bifurcation. Since helicity-based descriptors and geometric descriptors relative to the bifurcation have been shown to be significant predictors of disturbed shear, in principle they may be augmented by factors related to CCA geometry and hemodynamics.

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Vascular Wall Shear Stress in Clinical Practice

Cited by 17 publications

References 72 publications

On the shape of the common carotid artery with implications for blood velocity profiles

On the shape of the common carotid artery with implications for blood velocity profiles

Anatomic Characteristics of Culprit Sites in Acute Coronary Syndromes

An Insight into the Mechanistic Role of the Common Carotid Artery on the Hemodynamics at the Carotid Bifurcation

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