title: Global oxygen extraction fraction by blood sampling to anticipate cerebral hyperperfusion phenomenon after carotid artery stenting.
abstract: BACKGROUND
  Cerebral hyperperfusion syndrome sometimes occurs after carotid revascularization in patients with severe hemodynamic failure. To prevent cerebral hyperperfusion syndrome, cerebral hyperperfusion phenomenon (CHP) must be detected early. Single-photon emission computed tomography (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 a blood sampling method is useful for indicating CHP after 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 the cerebral arteriovenous oxygen difference. Cerebral blood flow was measured in the affected middle cerebral artery (MCA) territory and in the ipsilateral cerebellum by SPECT. The ratio of MCA to cerebellar activity was defined as cerebral blood flow in the affected MCA territory divided by cerebral blood flow in the ipsilateral cerebellar hemisphere. Probable CHP was defined as ≥10% increase in the ratio of MCA to cerebellar activity after CAS. The relationship between peri-CAS OEF and probable CHP was evaluated.
  
  
  RESULTS
  Of the 96 patients enrolled, 92 patients were analyzed. Probable CHP occurred in 17 patients. Post-CAS OEF was related to probable CHP (P < .01), but pre-CAS OEF was not. The receiver-operating characteristic curve showed that the cutoff value was 45% for probable CHP (P < .001).
  
  
  CONCLUSIONS
  An increase in blood sampling OEF immediately after CAS was related to probable CHP; then the oxygen demand should be reduced.
authors.affiliation: Department of Stroke Treatment, Shonan Kamakura General Hospital Stroke Center, Kamakura City, Kanagawa, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Iwata
authors.forename: Takahisa
authors.initials: T
authors.lastname: Mori
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Miyazaki
authors.forename: Yuhei
authors.initials: Y
authors.lastname: Tanno
authors.forename: Shigen
authors.initials: S
authors.lastname: Kasakura
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Aoyagi
mesh_terms: D000328:Adult; D000368:Aged; D019540:Area Under Curve; D001921:Brain / Q000098:blood supply*; D017536:Carotid Artery, Common / Q000601:surgery; D002343:Carotid Artery, Internal / Q000601:surgery; D016893:Carotid Stenosis / Q000601:surgery; D002548:Cerebral Revascularization / Q000009:adverse effects*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000032:analysis*; D012372:ROC Curve; D015607:Stents; D013577:Syndrome; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods
chemical_list: D010100:Oxygen