Cerebral hyperperfusion syndrome (CHS) is a rare but fatal perioperative complication after surgical correction of carotid stenosis. Despite numerous treatment options for preventing CHS, it does occur in some patients. We developed the outlet gate technique (OGT), in which the embolic balloon was deflated gradually in accordance with the ratio of oxygen saturation measured by a brain oximeter of the ipsilateral brain region to that in the contralateral region. Between June 2017 and May 2018, 39 patients with carotid stenosis underwent endovascular carotid revascularization procedures; of these, 20 underwent the procedure with the OGT. CBO was measured five times in those 20 patients: before the procedure, with the embolic protection device (EPD) on, with the EPD off, during the procedure, and after the procedure. Preventive treatment options were used more frequently in these patients, and although their surgical status seemed more complicated, perioperative complications were not increased. There were almost significant differences between CBO values except between those during and after the procedure with the OGT. This showed that the OGT allowed for stabilization of the CBO and thus has the potential to prevent CHS.
Keywords: Carotid artery stenting (CAS); Cerebral blood oxygenation (CBO); Cerebral hyperperfusion syndrome (CHS); Near-infrared spectroscopy (NIRS); Outlet gate technique (OGT).