The risk of stroke or clinical impairment after stereotactic radiosurgery for ARUBA-eligible patients.

BACKGROUND AND PURPOSE: The best management of patients with unruptured brain arteriovenous malformations (BAVM) is controversial. In this study, we analyzed the stroke rate and functional outcomes of patients having stereotactic radiosurgery (SRS) for unruptured BAVM using the same eligibility criteria and primary end points as the ARUBA trial.

METHODS: Retrospective observational study of 174 ARUBA-eligible patients having SRS from 1990 to 2005.

RESULTS: The median follow-up after SRS was 64 months. Fifteen patients (8.7%) had a hemorrhagic stroke at a median of 21 months after SRS. Six patients (3.5%) had a focal neurological deficit and 4 patients died (2.3%). The risk of stroke or death was 10.3% at 5 years and 11.5% at 10 years. Twelve additional patients (6.9%) had a focal neurological deficit from either radiation-related complications (n=7) or subsequent resection (n=5). The risk of patients' having clinical impairment (modified Rankin Score ≥ 2) was 8.4% at 5 years and 12.0% at 10 years. Increasing BAVM volume was associated with both stroke or death (hazard ratio=1.06; 95% confidence interval, 1.0-1.11; P=0.04) and clinical impairment (hazard ratio=1.06; 95% confidence interval, 1.01-1.09; P=0.01). The 10-year risk of stroke or death and clinical impairment for patients with BAVM ≤ 5.6 cm(3) was 5% and 4%, respectively.

CONCLUSIONS: The observed risk of stroke or death after SRS was approximately 2% per year for the first 5 years after SRS, declining to 0.2% annually for years 6 to 10. Patients with small volume BAVM may benefit from SRS compared with the natural history of unruptured BAVM over the planned follow-up interval of the ARUBA trial (5-10 years).