| CONTRIBUTION OF ARTERIAL WINDKESSEL IN LOW FREQUENCY CEREBRAL HEMODYNAMICS DURING TRANSIENT CHANGES IN BLOOD PRESSURE. | |
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MedLine Citation:
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PMID: 21292835 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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The Windkessel properties of the vasculature are known to play a significant role in buffering arterial pulsations, but their potential importance in dampening low frequency fluctuations in cerebral blood flow has not been clearly examined. In this study we assessed quantitatively the contribution of arterial Windkessel (peripheral compliance and resistance) in the dynamic cerebral blood flow response to relatively large and acute changes in blood pressure. Middle cerebral artery flow velocity (MCAv; transcranial Doppler) and arterial blood pressure were recorded from 14 healthy subjects. Lowpass filtered pressure-flow responses (< 0.15 Hz) during transient hypertension (intravenous phenylephrine) and hypotension (intravenous sodium nitroprusside) were fitted to a two-element Windkessel model. The Windkessel model was found to provide a superior goodness of fit to the MCAv responses during both hypertension and hypotension (R(2) = 0.89 ± 0.03 and 0.85 ± 0.05, respectively), with significant improvement in adjusted coefficients of determination (P < 0.005) compared with the single resistance model (R(2) = 0.62 ± 0.06 and 0.61 ± 0.08, respectively). No difference was found between the two interventions in the Windkessel capacitive and resistive gains, suggesting similar vascular properties during the pressure rise and fall episodes. The results highlight that low frequency cerebral hemodynamic responses to transient hypertension and hypotension may include significant contribution from the mechanical properties of vasculature, thus cannot be solely attributed to active control of vascular tone by cerebral autoregulation. The arterial Windkessel should be regarded as an important element of dynamic cerebral blood flow modulation during large and acute blood pressure perturbation. |
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Authors:
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Gregory S H Chan; Philip N Ainslie; Chris K Willie; Chloe E Taylor; Greg Atkinson; Helen Jones; Nigel H Lovell; Yu-Chieh Tzeng |
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Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-2-3 |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: - ISSN: 1522-1601 ISO Abbreviation: - Publication Date: 2011 Feb |
Date Detail:
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Created Date: 2011-2-4 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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1University of New South Wales. |
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