Document Detail

Pressure-autoregulation, CO2 reactivity and asymmetry of haemodynamic parameters in patients with carotid artery stenotic disease. A clinical appraisal.
MedLine Citation:
PMID:  12910394     Owner:  NLM     Status:  MEDLINE    
OBJECTIVES: Patients with carotid artery stenotic disease and poor cerebral haemodynamic reserve are in increased risk of stroke. Haemodynamic reserve can be estimated by measuring cerebrovascular reactivity induced by breathing CO2 and pressure-autoregulation by analyzing spontaneous slow fluctuation in arterial pressure and MCA blood flow velocity. We evaluated the relationship between clinical status, CO2 reactivity, pressure-autoregulation and other haemodynamic variables derived from Transcranial Doppler ultrasonography in patients with carotid artery disease. METHODS: 38 patients were investigated. Arterial pressure and blood flow velocity were monitored during CO2 reactivity tests. Arterial pressure-corrected and non-corrected indices of CO2 reactivity were calculated to compare an influence of rise in arterial pressure during the test. The pressure-autoregulation index was calculated as correlation coefficient between slow waves in blood flow velocity and arterial pressure. RESULTS: The increase in CO2 produced a consistent rise in arterial pressure and blood flow velocity and weakened the pressure autoregulation. The value of pressure-corrected CO2 reactivity was lower (p<0.0001) than the non-corrected one, indicating that the rise in arterial pressure during the test tends to over-estimate CO2 reactivity. The pressure-corrected reactivity was correlated with pressure autoregulation (r=-0.46; p<0.005). Both CO2 reactivity and pressure-autoregulation index correlated with a degree of carotid artery stenosis. Side-to-side difference of TCD pulsatility index demonstrated a close relationship with the asymmetry of stenosis (r=-0.61; p<0.0002) and symptoms (r=-0.49; p<0.003). CONCLUSIONS: When calculating CO2 reactivity in patients with carotid artery disease, changes in arterial pressure should be considered. Both CO2 reactivity and pressure-autoregulation describe the magnitude of haemodynamic deficit caused by stenosis, pulsatility index expresses the asymmetry of stenosis.
I Gooskens; E A Schmidt; M Czosnyka; St K Piechnik; P Smielewski; P J Kirkpatrick; J D Pickard
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Publication Detail:
Type:  Evaluation Studies; Journal Article    
Journal Detail:
Title:  Acta neurochirurgica     Volume:  145     ISSN:  0001-6268     ISO Abbreviation:  Acta Neurochir (Wien)     Publication Date:  2003 Jul 
Date Detail:
Created Date:  2003-08-11     Completed Date:  2003-12-17     Revised Date:  2009-11-11    
Medline Journal Info:
Nlm Unique ID:  0151000     Medline TA:  Acta Neurochir (Wien)     Country:  Austria    
Other Details:
Languages:  eng     Pagination:  527-32; discussion 532     Citation Subset:  IM    
Academic Neurosurgical Unit, Addenbrooke's Hospital, Cambridge, UK.
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MeSH Terms
Aged, 80 and over
Blood Flow Velocity / physiology
Blood Pressure / physiology*
Carbon Dioxide / administration & dosage,  diagnostic use*
Carotid Artery, Internal / physiopathology,  ultrasonography
Carotid Stenosis / physiopathology*,  ultrasonography
Cerebrovascular Circulation / physiology*
Hemodynamics / physiology*
Homeostasis / physiology*
Middle Aged
Reproducibility of Results
Ultrasonography, Doppler, Transcranial
Reg. No./Substance:
124-38-9/Carbon Dioxide

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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