Incidence of Early and In-hospital Late Seizures Following Aneurysmal Subarachnoid Hemorrhage in Patients Treated with Clazosentan: A Multicenter Retrospective Cohort Study.

Seizures following aneurysmal subarachnoid hemorrhage are clinically significant complications that may adversely affect neurological outcomes. Clazosentan sodium has been shown to reduce cerebral vasospasm and delayed cerebral ischemia; however, seizure occurrence during acute hospitalization in patients treated with clazosentan has not been well characterized. This multicenter retrospective cohort study included patients with aneurysmal subarachnoid hemorrhage who underwent surgical clipping or endovascular coiling and received clazosentan sodium for vasospasm prevention. Patients were followed from aneurysmal subarachnoid hemorrhage onset to hospital discharge. Early seizures were defined as acute symptomatic seizures occurring within 7 days of onset, and late seizures defined as seizures occurring on or after day 8; since follow-up was limited to hospitalization, late seizures were classified as in-hospital late seizures. Among 264 patients, early seizures occurred in eight patients (3.0%) and in-hospital late seizures in 4 (1.5%). The incidences of angiographic vasospasm and delayed cerebral ischemia were 17.0% and 16.0%, respectively. All patients received clazosentan therapy, and no non-clazosentan-treated control group was included. Although the incidences of seizures during hospitalization were relatively low compared with prior reports, differences in definitions, follow-up duration, and study design limit direct comparison. Given the single-arm design and limited observation period, causal relationships could not be inferred. These findings provide descriptive data on seizure occurrence during acute hospitalization in the contemporary era of vasospasm prevention, and should be interpreted as hypothesis-generating.