[Usefulness of Bilateral rSO₂ Monitoring for Predicting Cerebral Hyperperfusion Syndrome after Carotid Artery Stenting].

OBJECTIVE: Cerebral hyperperfusion syndrome(CHS)and cerebral hyperperfusion phenomenon(CHP)induce intracranial hemorrhage and can become critical complications after carotid artery stenting(CAS). The purpose of the present study was to predict and avoid CHS after CAS using bilateral rSO₂ intraoperative monitoring.

METHODS: We retrospectively analyzed 100 consecutive patients who underwent CAS between January 2012 and May 2014 in our institution. We performed continuous bilateral rSO₂ monitoring from anesthetic induction to the day following CAS. CHS was defined as the deterioration of neurological conditions post-CAS, no ischemic changes on post-CAS head CT or brain MRI, an increase in cerebral blood flow(CBF)and cerebral blood volume(CBV), and shortening of the mean transit time(MTT)or time to peak(TTP)on CT perfusion. To compare the CHS/CHP group and non-CHS/CHP group, we defined four parameters:rSO₂ difference(rSO₂ at the endpoint of the procedure-baseline rSO₂), ΔrSO₂ difference(affected side rSO₂ difference-unaffected side rSO₂ difference), rSO₂ ratio(rSO₂ at the endpoint of the procedure/baseline rSO₂), and ΔrSO₂ ratio(affected side rSO₂ ratio/unaffected side rSO₂ ratio).

RESULTS: There were 2 CHS cases(2.2%)and 3 CHP cases(3.3%). In the CHS/CHP group, the ΔrSO₂ difference and ΔrSO₂ ratio were significantly higher than those in the non-CHS/CHP group(p value<0.05);however, no significant differences were found in the affected side rSO₂ difference(p value=0.063)and affected side rSO₂ ratio(p value=0.054)between the groups.

CONCLUSION: We could promptly detect CHS and CHP in all cases by using continuous bilateral rSO₂ monitoring and analysis of the ΔrSO₂ difference and ΔrSO₂ ratio.