Long-term Outcomes After Different Management Strategies for High-level Cerebral Arteriovenous Malformation

Arteriovenous malformations (AVMs) are complex and rare cerebral vascular dysplasia. The main purpose of treatment is to avoid the neurological impairment caused by hemorrhagic stroke. The Spetzler-Martin (SM) grading system is widely used to estimate the risk of postoperative complication based on maximum AVM nidus diameter, pattern of venous drainage, and eloquence of location. Generally, grade I and II are amenable to surgical resection alone. Grade III is typically treated via a multimodal approach, including microsurgical resection, embolization, and radiosurgery (SRS). Grade IV and V are generally observed unless ruptured. However, some previous studies indicated that despite the high rate of poor outcomes for high-level unruptured AVMs, the mortality for high-level unruptured AVMs are likely lower than untreated patients. With the development of new embolic materials and new intervention strategies, patients with high-level AVMs may have more opportunities to underwent more aggressive interventions. The OHAVM study aims to clarify the clinical outcomes for patients with SM grade IV and V AVMs after different management strategies.