Endovascular treatment accounts for a change in brain arteriovenous malformation natural history risk.

This study estimated the risk and rates of intracranial hemorrhage (ICH) in patients harbor-ing brain arteriovenous malformation (BAVM) after endovascular embolization. One hundred and forty-four consecutive patients with BAVM treated with endovascular embolization between 1998 and 2003 were retrospectively reviewed. The risk of ICH subsequent to endovascular embolization was studied using Kaplan-Meier curves. We reviewed 144 patients with BAVM treated with endovascular embolization. Two hundred and sixty-nine procedures were performed, 69 were performed with silk sutures, 18 with coils, 137 with NBCA and 36 with Onyx18. Twenty-three (16.0%) patients were treated with additional gamma-knife radiosurgery and one (0.7%) with additional surgical AVM excision. Complete obliteration of BAVMs was achieved in 20 patients (13.9%). During a mean follow-up of 5.9 years for the ICH group and 6.9 years for the non-ICH group, hemorrhages occurred in 11 (17.7%) of the ICH patients and in nine (11%) of the non-ICH group (p>0.1). The annual risk of hemorrhage was 3.0% and 1.6%, respectively. In the multivariate regression model, the adjusted relative risk (RR) for hemorrhage at initial presentation was 1.6 (95% CI 1.2-3.2; p>0.1). Deep venous drainage, male sex, age or AVM size were not significantly associated with subsequent hemorrhage. ICH and non-ICH groups did not differ in progression to subsequent ICH after endovascular embolization (log-rank X (2) =1.339, p>0.1) in survival analyses. The overall annual hemorrhage risk for all patients after endovascular embolization was 2.1%. Endovascular embolization alone or combined with gamma-knife radiosurgery or surgical treatment are able to decrease ICH occurrence compared to abstention.