Intraoperative electroencephalographic changes during transcarotid artery revascularization are more frequent than previously reported

Abstract

Objective: Up to 14% of patients undergoing carotid endarterectomy with continuous electroencephalographic (EEG) neuromonitoring will require shunt placement because of EEG changes. However, the initial studies of transcarotid artery revascularization (TCAR) found only one patient with temporary EEG changes. We report our experience with intraoperative EEG monitoring during TCAR.

Methods: We conducted a retrospective review of patients who underwent TCAR at two urban hospitals within an integrated healthcare network from May 2017 to January 2020. The data included demographic information, patient comorbidities, symptom status, previous carotid interventions, anatomic details, contralateral disease, intraoperative vital signs and EEG changes, and postoperative major adverse events (transient ischemic attack, stroke, myocardial infarction [MI], and death) both initially and at 30 days postoperatively. The Fisher exact test was used for categorical data and the Wilcoxon rank sum test for continuous data.

Results: A total of 89 patients underwent TCAR during the study period, of whom 71 (79.8%) received intraoperative EEG neuromonitoring. Of the 89 patients, 70.8% were men and 29.2% were women. The median age was 75 years (IQR, 68-82.5 years). Symptomatic patients accounted for 41.6% of the cohort. Of the 71 patients who received continuous neuromonitoring, 9 experienced EEG changes during TCAR (12.7%). The changes resolved in seven patients with pressure augmentation in three and switching to a low flow toggle in three. One patient who had sustained EEG changes had a new postoperative neurologic deficit. The median carotid stenosis percentage on preoperative computed tomography angiography was lower for patients with EEG changes than for those without (67% vs 80%; P = .01). No correlation was found between symptom status or 30-day stroke in patients with and without EEG changes (P = .49 and P = .24, respectively). Overall, three postoperative strokes, two postoperative deaths, and one MI occurred, for a composite 30-day stroke, death, and MI rate of 6.7%.

Conclusions: Changes in continuous EEG monitoring were more frequent in our study than previously reported. Less severe carotid stenosis might be associated with a greater incidence of EEG changes. Limited data are available on the prognostic ability of EEG to detect clinically relevant changes during TCAR, and further studies are warranted.

Keywords: Carotid stent; EEG; Neuromonitoring; TCAR.