Background: Cerebral hyperperfusion syndrome (CHS) sometimes occurs after carotid revascularization in patients with severe hemodynamic failure. To prevent CHS, cerebral hyperperfusion phenomenon (CHP) must be detected early. SPECT is useful for detecting CHP, but it is impractical on a daily basis. A tool with high availability to find CHP is desired.
Objective: To investigate whether global oxygen extraction fraction (OEF) by blood sampling method is useful for indicating CHP following carotid artery stenting (CAS).
Methods: When patients underwent elective CAS from September 2010 to August 2012, we performed blood sampling for OEF calculation and SPECT before and immediately after elective CAS. Data were collected prospectively. OEF was calculated from cerebral arteriovenous oxygen difference. Cerebral blood flow (CBF) was measured in the affected middle cerebral artery (MCA) territory and in the ipsilateral cerebellum by SPECT. MCA-to-cerebellar activity (MCA/CE) ratio was defined as CBF in the affected MCA territory divided by CBF in the ipsilateral cerebellar hemisphere. Probable CHP was defined as 10% or more increase in MCA/CE ratio following CAS. Evaluated were the relationship between peri-CAS OEF and probable CHP.
Results: Ninety-six patients were enrolled and 92 patients analyzed. Probable CHP occurred in 17 patients. Post-CAS OEF was related to probable CHP (p<0.01), but pre-CAS OEF wasn't. The ROC curve showed that the cut-off value was 45% for probable CHP (p<0.0001).
Conclusion: Increase of blood sampling OEF immediately after CAS was related to probable CHP, and then oxygen demand should be reduced.
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