| Time delay as a parameter for cerebrovascular reactivity in patients with severe carotid stenosis. | |
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MedLine Citation:
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PMID: 12766356 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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BACKGROUND: Amplitude responsiveness of cerebral blood flow velocity (CBFV) to CO(2) is an established test of cerebrovascular reserve capacity. We aimed to analyze the time course of CBFV during CO(2 )reactivity testing in patients with severe carotid stenosis. METHODS: 87 patients were assigned to three different groups according to the degree of stenosis (A 75-89%, B 90-94%, C 95-100%) and CBFV dynamics was assessed by transcranial Doppler sonography during hypercapnia induced by inhalation of 7% CO(2. )Time constants for the duration of CBFV and the end-tidal CO(2 )partial pressure (Pet(CO2)) increase and decrease were calculated. In addition, time delays between subsequent changes of Pet(CO2) and CBFV during on- and offset of hypercapnia were determined. RESULTS: There was a significant reduction of conventional CO(2) reactivity on the side ipsilateral to the stenosis in all groups. Time constants of CBFV showed no major differences between ipsi- and contralateral sides or between different groups. The off delay between the decrease in Pet(CO2) and the consequent decrease in CBFV was the only out of 6 different dynamic parameters which significantly differentiated critical stenosis and occlusion from severe stenosis. Retest variability showed a highly significant correlation. CONCLUSIONS: Analysis of the dynamic CBFV response during the applied CO(2) inhalation protocol revealed a significant and reproducible delay parameter which has power to detect cerebral hemodynamic compromise in patients with carotid artery stenosis similar to the conventional CO(2 )reactivity parameter. |
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Authors:
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A Hetzel; B Guschlbauer; M Reinhard |
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Publication Detail:
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Type: Clinical Trial; Journal Article |
Journal Detail:
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Title: Cerebrovascular diseases (Basel, Switzerland) Volume: 16 ISSN: 1015-9770 ISO Abbreviation: Cerebrovasc. Dis. Publication Date: 2003 |
Date Detail:
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Created Date: 2003-05-26 Completed Date: 2003-07-17 Revised Date: 2004-11-17 |
Medline Journal Info:
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Nlm Unique ID: 9100851 Medline TA: Cerebrovasc Dis Country: Switzerland |
Other Details:
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Languages: eng Pagination: 14-20 Citation Subset: IM |
Copyright Information:
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Copyright 2003 S. Karger AG, Basel |
Affiliation:
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Department of Neurology and Clinical Neurophysiology, University Clinics of Freiburg, Germany. hetzel@nz11.ukl.uni-freiburg.de |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Aged Blood Pressure / physiology Carbon Dioxide / diagnostic use Carotid Stenosis / physiopathology*, ultrasonography Cerebrovascular Circulation / physiology* Female Humans Male Time Factors Ultrasonography, Doppler, Transcranial |
| Chemical | |
Reg. No./Substance:
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124-38-9/Carbon Dioxide |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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