| Importance of flow division on transition to turbulence within an arteriovenous graft. | |
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MedLine Citation:
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PMID: 16904678 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Transitional blood flow in an arteriovenous graft under various conditions of flow division was examined through direct numerical simulation. This junction consists of an inlet vessel (prosthetic graft) connected to a host vessel (vein) at an acute angle (21.6 degrees ). Inlet Reynolds numbers, based on mean velocity and graft inlet diameter, ranged from 800 to 1400. Various flow divisions between the two ends of the host vessel (i.e., the proximal venous segment, PVS, and distal venous segment, DVS) were considered (PVS:DVS ratios of 100:0, 85:15, 70:30 and 115:(15)). The numerical technique employed the spectral element method which is a high-order discretization ideally suited to the simulation of transitional flows in complex domains. High velocity and pressure fluctuations were observed for the PVS:DVS=70:30 and 85:15 cases and absent from the 100:0 and 115:(15) cases; the results indicate the importance of flow division on the development of turbulence in this junction. Transition to turbulence was observed at Reynolds numbers as low as 1000 and 800 under flow divisions of 85:15 and 70:30, respectively, significantly lower than the critical value of 2100. The frequency spectra of velocity fluctuations indicated a significant intensity within the frequency range of approximately 300Hz downstream of the junction. An adverse pressure gradient developed in the PVS when graft inflow divided into opposite directions in the junction. This pressure gradient had a destabilizing effect on the flow and enhanced transition to turbulence in the PVS. These findings suggest that measurements of in vivo flow rates at the inlet and outlets are critical for the accurate prediction of arteriovenous hemodynamics. A potential clinical application of these results might be to close off the DVS during graft construction to ensure a 100:0 flow division. |
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Authors:
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Sang-Wook Lee; David S Smith; Francis Loth; Paul F Fischer; Hisham S Bassiouny |
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Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S. Date: 2006-08-10 |
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: 2007-03-12 Completed Date: 2007-05-31 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: 981-92 Citation Subset: IM |
Affiliation:
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Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, London, Ont., Canada N6A 5K8. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Arteriovenous Shunt, Surgical / methods* Blood Vessel Prosthesis* Dogs Hemorheology* Models, Biological Pulsatile Flow / physiology* |
| Grant Support | |
ID/Acronym/Agency:
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2R01HL55296-04A2/HL/NHLBI NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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