Intraoperative EEG Changes During TCAR are more Frequent than Previously Reported.

Up to 14% of patients undergoing carotid endarterectomy (CEA) with continuous electroencephalographic (EEG) neuromonitoring require shunt placement due to EEG changes. 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.
We conducted a retrospective review of patients from May 2017 to January 2020 who received TCAR at two urban hospitals within an integrated healthcare network. Data included demographic information, patient comorbidities, symptom status, prior carotid interventions, anatomic details, contralateral disease, intra-operative vital signs and EEG changes, and post-operative major adverse events (transient ischemic attack (TIA), stroke, myocardial infarction (MI), and death) both initially and 30 days post-operatively. Fisher’s Exact test was used for categorical data, while continuous data was analyzed with Wilcoxon Rank Sum.
A total of 89 patients underwent TCAR during the study period, of which 71 (79.8%) had intraoperative EEG neuromonitoring. 70.8% of patients were male. Median age was 75 years (IQR 68-82.5). Symptomatic patients accounted for 41.6% of the cohort. Of the 71 patients who had continuous neuromonitoring, nine had EEG changes during TCAR (12.7%). Changes resolved in 7 patients with pressure augmentation (3) and switching to low flow toggle (3). One patient who had sustained EEG changes had a new post-operative neurologic deficit. Median carotid stenosis percentage on pre-operative CT angiography was lower for patients with EEG changes than those without (67% vs 80%, p=.09). There was no correlation between symptom status or 30-day stroke in patients with and without EEG changes (P=0.49 and 0.24, respectively). Overall there were three post-operative strokes, two post-operative deaths, and one myocardial infarction, for a 30-day stroke/death/MI rate of 6.7%.
Changes in continuous EEG were more frequent in our study than previously reported. Less severe carotid stenosis may be associated with a higher incidence of EEG changes. There is limited data on the prognostic ability of EEG to detect clinically relevant changes during TCAR, and further study is warranted.

Copyright © 2021. Published by Elsevier Inc.