Abstract TMP2: Longitudinal Risk of Seizures in Patients With Brain Arteriovenous Malformations

Abstract

Objective: To examine longitudinal risk of seizures following diagnosis of brain arteriovenous malformations (bAVM). Methodology: A total of 1178 patients diagnosed with bAVM and enrolled into a prospective cohort study at our institution from 2000-2023 were included. We calculated the incidence rate (IR) of seizures pre- and post-bAVM treatment, censoring at either treatment, death, or last follow-up. Cox regression models tested whether treatment was associated with seizures during follow-up using treatment as a time-varying covariate (no treatment, radiosurgery only, and surgical resection),adjusting for age at diagnosis, prior seizure, prior hemorrhage, bAVM size, and lobar location. Results: The bAVM cohort was 51% female, 29% children (median age 9.5y, range 0-19y), and 71% adults (median age 44.5y, range 20-89y). 290 (25%) presented with seizures that led to bAVM diagnosis; of these, 52 had both acute seizures and hemorrhage at presentation. A total of 72 patients had seizure after diagnosis but before treatment over 2296 patient-years (PY) of follow-up (IR 3.1 per 100 PY, 95% CI: 2.5-4.0). Post-treatment, there were 167 seizures during 4712 PY of follow-up (4.8 per 100 PY, 95% CI: 4.2-5.5). Compared to untreated patients, treated patients were at 2-fold higher risk of seizures during follow-up (Figure) with either radiosurgery (HR=2.3, 95% CI: 1.6-3.2, P<0.001) or surgical resection (HR=1.9, 95% CI: 1.4-2.7, P<0.001). Prior seizures (HR=2.2, 95% CI: 1.6-3.0), lobar location (HR=1.9, 95% CI: 1.2-3.0), and AVM size (HR=1.11, 95% CI: 1.0-1.2) were independent predictors of seizures while prior hemorrhage (P=0.451) and age at diagnosis (P=0.481) were not. Conclusion: Risk of seizure persisted for decades after bAVM diagnosis, but highest in the years following bAVM treatment, independent of prior seizures, age at diagnosis, lobar location, AVM size or prior hemorrhage. This suggests greater attention is needed for seizure management after bAVM treatment.