Objective:

To characterize EEG responses to intra-arterial verapamil administration during angiographic treatment of cerebral vasospasm in aneurysmal subarachnoid hemorrhage patients.

Background:

Intra-arterial vasodilators like verapamil are commonly used to treat symptomatic cerebral vasospasm in aneurysmal subarachnoid hemorrhage (aSAH). However, their neurophysiologic effects remain poorly understood. Continuous EEG has the potential to study these effects and evaluate individual treatment responses following drug administration. While case studies have reported postprocedural improvements in EEG parameters associated with delayed cerebral ischemia (e.g. Claassen et al., 2004), studies on larger cohorts are lacking. 

Design/Methods:

We retrospectively identified aSAH patients admitted to our Neurointensive Care Unit between 2015 and 2023 who underwent angiographic treatment for cerebral vasospasm with administration of intra-arterial verapamil. Following EEG artifact reduction and feature extraction, we computed mean band powers, alpha-delta ratio (ADR), and relative alpha variability (RAV) across four time intervals: a 6-hour baseline following admission and 3 periprocedural intervals (12 to 6 hours before procedure start, 6 to 0 hours before procedure start, and 0 to 6 hours after procedure finish). Means were compared via repeated measures ANOVAs and pairwise comparisons with Bonferroni correction. 

Results:

24 patients (mean age 55.2 ± 12.0, 79.2% women, Hunt Hess 3.5 ± 0.9, modified Fisher 3.8 ± 0.4) underwent 48 angiograms with verapamil administration (mean dose 26.0 ± 11.3 mg, 8.9 ± 2.6 days after bleed, 16.7% with angioplasty). Patients showed significant decreases in beta power and ADR (p < 0.01) from baseline to the periprocedural time intervals. However, no mean differences were seen across power bands, ADR, or RAV values between the three periprocedural time intervals.

Conclusions:

Early analysis does not show clear group-level differences in qEEG parameters when comparing six-hour intervals pre vs post intra-arterial verapamil administration. Further analyses will explore whether modeling trajectories or accounting for individual variability provides greater insight.