| Helical flow as fluid dynamic signature for atherogenesis risk in aortocoronary bypass. A numeric study. | |
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MedLine Citation:
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PMID: 16626721 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The main purpose of the study was to verify if helical flow, widely observed in several vessels, might be a signature of the blood dynamics of vein graft anastomosis. We investigated the existence of a relationship between helical flow structures and vascular wall indexes of atherogenesis in aortocoronary bypass models with different geometric features. In particular, we checked for the existence of a relationship between the degree of helical motion and the magnitude of oscillating shear stress in conventional hand-sewn proximal anastomosis. The study is based on the numerical evaluation of four bypass geometries that are attached to a simplified computer representation of the ascending aorta with different angulations relative to aortic outflow. The finite volume technique was used to simulate realistic graft fluid dynamics, including aortic compliance and proper aortic and graft flow rates. A quantitative method was applied to evaluate the level of helicity in the flow field associated with the four bypass models under investigation. A linear inverse relationship (R = -0.97) was found between the oscillating shear index and the helical flow index for the models under investigation. The results obtained support the hypothesis that an arrangement of the flow field in helical patterns may elicit damping in wall shear stress temporal gradients at the proximal graft. Accordingly, helical flow might play a significant role in preventing plaque deposition or in tuning the mechanotransduction pathways of cells. Therefore, results confirm that helical flow constitutes an important flow signature in vessels, and its strength as a fluid dynamic index (for instance in combination with magnetic resonance imaging flow visualization techniques) for risk stratification, in the activation of both mechanical and biological pathways leading to fibrointimal hyperplasia. |
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Authors:
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Umberto Morbiducci; Raffaele Ponzini; Mauro Grigioni; Alberto Redaelli |
Publication Detail:
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Type: Journal Article Date: 2006-04-19 |
Journal Detail:
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Title: Journal of biomechanics Volume: 40 ISSN: 0021-9290 ISO Abbreviation: J Biomech Publication Date: 2007 |
Date Detail:
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Created Date: 2007-01-22 Completed Date: 2007-03-20 Revised Date: 2009-11-11 |
Medline Journal Info:
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Nlm Unique ID: 0157375 Medline TA: J Biomech Country: United States |
Other Details:
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Languages: eng Pagination: 519-34 Citation Subset: IM |
Affiliation:
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Department of Mechanics, Università Politecnica delle Marche, Ancona, Italy. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Biomechanics Coronary Artery Bypass* Coronary Artery Disease / etiology*, physiopathology Coronary Vessels / physiology* Data Interpretation, Statistical Hemorheology* Models, Biological* Risk |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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