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

Study on the Long-term Outcomes of 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.

Follow-up: In our neurosurgical center, follow-up was conducted for all patients at the first 3-6 months and annually after discharge by clinical visit and telephone interview.

Study overview: The population in the OHAVM study will be divided into two parts. Clinical and imaging data of high-level AVM patients from 2012/04 to 2019/09 were retrospectively collected. And the high-level AVM patients from 2019/09 to 2019/12 were prospectively collected. The intervention strategies in our institution for high-level AVMs are of four categories: microsurgical resection, embolization, embolization+radiosurgery, and single-stage hybrid surgery (embolization-resection). Each participants will be followed at least for 5 year since enrollment. Finally, we will clarify the clinical outcomes and prognostic predictors for patients with SM grade IV and V AVMs after different management strategies.

Sample size: About 1000 patients will be enrolled in this study, and half of them were unruptured. The population distribution of different management strategies is expected as follows: conservative:100 cases, microsurgical resection: 300 cases, embolization:250 cases, embolization+radiosurgery: 250 cases, single-stage hybrid surgery: 100 cases.

Study endpoints: The neurological function prognosis, occlusion rate and complications were evaluated at 2 weeks, 1 year, 3 years, 5 years after the treatment and the last follow-up, respectively.

Inclusion Criteria:

1. The diagnosis of AVM was confirmed with digital subtraction angiography (DSA) and/or magnetic resonance imaging(MRI).
2. The SM grade was IV and V.

Exclusion Criteria:

1. Patients with multiple AVMs.
2. Patients with hereditary hemorrhagic telangiectasia (HHT).
3. Patients with missing clinical and imaging data.