1099. Functional Outcome in Untreated and Radiosurgically Treated Patients with High-Grade AVMs

Authors: Jason Anthony Liew; Wuyang Yang, MD, MS; Risheng Xu, MD, PhD; Yuxi Chen; James Feghali, MD; Justin Caplan, MD; Rafael Tamargo, MD; Judy Huang, MD (Baltimore, MD)

Introduction : Though optimal treatment paradigms for low-grade arteriovenous malformations(AVMs) have been suggested, the same level of evidence does not exist for high-grade AVMs. Based on recent literature, stereotactic radiosurgery may be a viable option in the intervention of high-grade AVMs. We aim to clarify the functional outcome following radiosurgical treatment in this population by comparing them with untreated patients. Methods: All Spetzler-Martin grade IV and V AVM patients seen at our institution from 1990-2017 were retrospectively reviewed. Patients were divided into two groups based on whether they received stereotactic radiosurgery or were conservatively managed. Improvement in mRS was the primary outcome. Secondary outcomes included mRS and clinical features at last follow-up as well as obliteration and hemorrhage rates. Results: A total of 113 patients with Grade IV and V AVMs were included, 68(60.2%) of these patients were treated. The average age of untreated patients was 37.6 years versus 29.5 years in treated patients(p=0.021). 30.9%(n=21) of patients in the treated group presented with a ruptured AVM compared with 24.4%(n=11) of untreated with patients. 25.0%(n=17) of treated patients achieved obliteration while none of the untreated patients experienced obliteration(p<0.001). There was no difference in mRS improvement between the groups(26.5%(n=18) of treated vs. 17.8%(n=8) of untreated,p=0.282). Risk of hemorrhage during the follow-up period also did not differ significantly(16.2%(n=11) of treated vs. 15.6%(n=7) of untreated,p=0.930). Follow-up duration was similar in treated and untreated patients (7.94 years vs. 8.95 years respectively). In a multivariable analysis, risk of hemorrhage at follow-up were significantly associated with ruptured AVM at presentation but not treatment or AVM size. Conclusion: High-grade brain AVMs are complex lesions which present extensive management challenges. In our study radiosurgery confers a 25% chance of obliteration without increased risk of hemorrhage or worsened functional outcome at follow-up when compared to untreated patients.