The natural history of arteriovenous malformations is currently being studied in a prospective trial. Radiosurgery is an important therapeutic option for patients.

     The ARUBA trial is designed to determine whether medical management improves long-term outcomes in patients with unruptured brain arteriovenous malformations (AVM) compared to interventional therapy.

     The median patient age was 42.8 years. This was a retrospective review of 164 ARUBA-eligible patients having stereotactic radiosurgery (SRS) from 1990-2005 with more than two years of follow-up.

       Sixty-five AVMs (40%) were Spetzler-Martin grade I-II; the median radiosurgery-based AVM score (RBAS) was 1.48. The median follow-up was 67.5 months; 44 patients (27%) had 10 or more years of follow-up.

     Fifteen patients (9%) bled at a median of 21 months (range, 7-70) after SRS. Six patients (4%) had new deficits and 4 patients died (2%). The risk of stroke was 10% at 5-years and 11% at 10-years. Twelve additional patients (7%) had a Modified Rankin Scale (MRS) decline from either radiation-related complications (n=7) or subsequent resection (n=5). The risk of MRS decline was 13% at 5-years and 16% at 10-years. Factors associated with MRS decline were increasing AVM volume (P=0.002), higher AVM grade (P=0.01), and higher RBAS (P=0.002). The 5-year and 10-year risk of MRS decline for patients with Spetzler-Martin grade I-II AVMs or a RBAS less than 1.5 was 5%.

     This is a retrospective study.

     The observed risk of stroke and MRS decline after SRS was similar to the expected risk in the medical management group of ARUBA at the planned follow-up interval of that trial (5-year risk, 5%-20%).

     Younger patients with small, unruptured AVMs may benefit from SRS compared to medical management at longer follow-up periods.