Outcomes following stereotactic radiosurgery for high-grade brain arteriovenous malformations: a systematic review and meta-analysis

OBJECTIVE Arteriovenous malformations (AVMs) of the brain are a leading cause of stroke in the young and carry a lifetime risk of intracerebral hemorrhage. The management options for high-grade AVMs are limited. Resection is often associated with high rates of postoperative morbidity, and the results of stereotactic radiosurgery (SRS) for these lesions thus far have been mixed. The aim of this study was to summate the published data on the outcomes of SRS for high-grade AVMs in order to better inform the management of these otherwise untreatable lesions. METHODS A search of four online databases for literature pertaining to the use of SRS to treat high-grade (Spetzler-Martin grades IV–VI) AVMs was performed. Data pertaining to AVM obliteration, incidence of adverse radiation effects (AREs), and posttreatment hemorrhage were extracted, and a meta-analysis of proportions was performed. The study protocol was prospectively registered with PROSPERO. RESULTS Fifteen studies describing the results of SRS treatment of 562 high-grade AVMs were analyzed. The overall rate of AVM obliteration during a median follow-up period of 50 months was 34.2% (95% CI 27.0%–42.1%, I 2 = 65.1%). The pooled rate of hemorrhage following SRS treatment was 12.2% (95% CI 7.8%–18.7%, I 2 = 25%). For previously ruptured AVMs, the rate of hemorrhage was 12.7% (95% CI 8.5%–18.7%, I 2 = 0%) compared with 5.2% (95% CI 1.0%–23.1%, I 2 = 0%) for unruptured AVMs. The overall incidence of AREs was 9.3% (95% CI 5.2%–15.9%, I 2 = 0%). CONCLUSIONS SRS for high-grade AVMs is associated with a modest rate of obliteration and is complicated by AREs in 9% of cases. Patients harboring previously ruptured AVMs or lesions with high-risk angioarchitectural features may be more likely to benefit from this treatment.