Background It is required to anticipate cerebral hyperperfusion syndrome (CHS) following elective carotid artery stenting (eCAS).

Purpose The purpose of our retrospective study was to investigate whether or not blood sampling oxygen extraction fraction (OEF) had relation to CHS following eCAS.

Methods Included in our analysis were patients (1) who underwent eCAS in our institution between October 2010 and May 2014, and (2) who underwent blood sampling for OEF calculation just before and immediately after eCAS, and (3) who underwent SPECT before and just after eCAS. OEF was calculated from cerebral arteriovenous oxygen difference. Arterial blood was sampled from the common carotid artery and venous blood from the dominant-sided superior jugular bulb. CHS was defined as restlessness or altered level of conscious in addition to classical triad of headache, seizure or neurological symptoms not due to cerebral ischemia within seven days following CAS. CBF was measured before and just after eCAS. CBF increase in the eCAS side was defined as follows; (post-CAS CBF ratio - pre-CAS CBF ratio) of more than 10%, where CBF ratio was defined as CBF in the CAS-sided MCA territory divided by ipsilateral cerebellar CBF (%). Evaluated were baseline features in patients, pre-CAS OEF, post-CAS OEF, CBF ratio, CBF increase and the incidence of CHS.

Results Median pre-CAS OEF and post-CAS OEF were 0.41 and 0.42, respectively. Nine patients presented CHS. Scattergrams of the two groups with CHS and without CHS showed that the cut-off values of the pre-CAS OEF, the post-CAS OEF, the pre-CAS CBF ratio and the increase of CBF ratio to anticipate CHS were more than 0.46 (p < 0.01), more than 0.49 (p < 0.001), less than 81% (p < 0.05), and more than 8.8%(p < 0.01), respectively. Multiple stepwise and logistic regression analysis demonstrated that pre-CAS OEF and post-CAS OEF were independent determinants of CHS (p < 0.05 and p < 0.001, respectively).

Conclusion Elevation of blood sampling pre-CAS or post-CAS OEF can anticipate CHS following eCAS.

Disclosures T. Mori: 2; C; Kaneka Medix. 6; C; Medikit. T. Iwata: None. Y. Tannoo: None. S. Kasakura: None. K. Yoshioka: None.