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Global Oxygen Extraction Fraction by Blood Sampling to Anticipate Cerebral Hyperperfusion Phenomenon After Carotid Artery Stenting

Iwata, Tomonori MD; Mori, Takahisa MD, PhD; Miyazaki, Yuichi MD; Tanno, Yuhei MD; Kasakura, Shigen MD; Aoyagi, Yoshinori MD

doi: 10.1227/NEU.0000000000000485
Research-Human-Clinical Studies

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).

CONCLUSION: An increase in blood sampling OEF immediately after CAS was related to probable CHP; then the oxygen demand should be reduced.

ABBREVIATIONS: AVDO2, arteriovenous oxygen difference

AI, asymmetry index

CAS, carotid artery stenting

CEA, carotid endarterectomy

CBF, cerebral blood flow

CHP, cerebral hyperperfusion phenomenon

CHS, cerebral hyperperfusion syndrome

CMRO2, cerebral metabolic rate of oxygen

123I-IMP, I123-labeled N-isopropyl-p-iodoamphetamine

IQR, interquartile range

MCA, middle cerebral artery

MCA/CE, ratio of middle cerebral artery to cerebellar activity

OEF, oxygen extraction fraction

rCBF, regional cerebral blood flow

SPECT, single-photon emission computed tomography

Department of Stroke Treatment, Shonan Kamakura General Hospital Stroke Center, Kamakura City, Kanagawa, Japan

Correspondence: Takahisa Mori, MD, PhD, Department of Stroke Treatment, Shonan Kamakura General Hospital Stroke Center, Okamoto 1370-1, Kamakura City, Kanagawa 247-8533, Japan. E-mail:

Received March 17, 2014

Accepted June 18, 2014

Copyright © by the Congress of Neurological Surgeons