[Usefulness of Bilateral RSO 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 rSO 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 rSO 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:rSO difference(rSO at the endpoint of the procedure-baseline rSO), ΔrSO difference(affected side rSO difference-unaffected side rSO difference), rSO ratio(rSO at the endpoint of the procedure/baseline rSO), and ΔrSO ratio(affected side rSO ratio/unaffected side rSO ratio).

Results: There were 2 CHS cases(2.2%)and 3 CHP cases(3.3%). In the CHS/CHP group, the ΔrSO difference and ΔrSO 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 rSO difference(p value=0.063)and affected side rSO ratio(p value=0.054)between the groups.

Conclusion: We could promptly detect CHS and CHP in all cases by using continuous bilateral rSO monitoring and analysis of the ΔrSO difference and ΔrSO ratio.