Compensatory mechanisms for chronic cerebral hypoperfusion in patients with carotid occlusion.
BACKGROUND AND PURPOSE: The purpose of this experiment was to assess long-term cerebral hemodynamic and metabolic changes in patients with increased oxygen extraction fraction (OEF) in the hemisphere distal to an occluded carotid artery who remain free of stroke. Methods--Ten patients with increased OEF and no interval stroke underwent repeated positron emission tomography examinations 12 to 59 months after the initial examination. Quantitative regional measurements of cerebral blood flow, cerebral blood volume, cerebral rate of oxygen metabolism (CMRO2), and OEF were obtained. Regional measurements of the cerebral rate of glucose metabolism (CMRGlc) were made on follow-up in 5 patients. Statistical significance (P<0.05) was measured with t tests and linear regression analysis. RESULTS: The ipsilateral/contralateral OEF ratio declined from a mean of 1.16 to 1.08 (P=0.022). Greater reductions were seen with longer duration of follow-up (P=0.023, r=0.707). The cerebral blood flow ratio improved from 0.81 to 0.85 (P=0.021). No change in cerebral blood volume or CMRO2 was observed. CMRGlc was reduced in the ipsilateral hemisphere (P=0.001 compared with normal), but the CMRO2/CMRGlc ratio was normal. CONCLUSIONS: Increased OEF improves in patients with carotid occlusion and no interval stroke. This improvement in OEF is due to an improvement in collateral blood flow.
Duke Scholars
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Related Subject Headings
- Tomography, Emission-Computed
- Oxygen Consumption
- Neurology & Neurosurgery
- Middle Aged
- Male
- Humans
- Glucose
- Follow-Up Studies
- Female
- Chronic Disease
Citation
Published In
DOI
ISSN
Publication Date
Volume
Issue
Start / End Page
Location
Related Subject Headings
- Tomography, Emission-Computed
- Oxygen Consumption
- Neurology & Neurosurgery
- Middle Aged
- Male
- Humans
- Glucose
- Follow-Up Studies
- Female
- Chronic Disease