Safety and Efficacy of Staged Embolization for Management of High-risk Dural Arteriovenous Fistulas

Introduction: High-risk dural arteriovenous fistulas (dAVFs) carry significant risk of hemorrhage or neurological deficits, with features like cortical venous reflux complicating treatment. First-line management, depending on location, typically involves endovascular embolization. The decision to obliterate the dAVF in a single session or multiple embolizations is multifactorial and often subject to proceduralist preference. This study aims to compare outcomes of high-grade dAVF management between single and staged embolization methods to guide clinical decision making.

Methods: Retrospective review of a prospectively maintained database at a single urban health system identified all patients from January 2015 to February 2024 who presented with high-risk dAVFs. High-risk was defined as Cognard IIb, IIa+b, III, and IV. Clinical data, structural and hemodynamic characteristics of the dAVF, rate of favorable clinical outcomes defined as a modified Rankin Scale (mRS) of 0-2, and technical parameters including anatomic approach, embolic agent used, complications, and success were reviewed and were compared based on embolization strategy.

Results: Of 76 patients, 53 (69.7%) underwent single-stage embolization and 23 (30.3%) underwent staged embolization. Selection of patients for single or multi-stage embolization did not differ significantly by age, initial mRS, presenting symptoms, or location of dAVF. Multi-stage embolization was more frequently performed in patients with recurrent dAVFs (30.4% vs 5.7%, p=0.01). Patients who received multi-stage embolizations were more likely to receive embolizations through a combination of transarterial and transvenous approaches (p < 0.001). Choice of embolic material, rates of postoperative complications like hemorrhage or permanent neurological injury, and need for adjunctive surgery did not differ between strategies. Both cohorts experienced similar rates of symptom resolution (79.2% vs 73.9%, p=0.831) and angiographic obliteration (66.0% vs. 60.9%, p=0.864) on follow-up.

Conclusion : Staging embolization of high-grade dAVFs does not affect overall clinical or angiographic outcomes. The decision to stage should be made according to relevant procedural characteristics including favorable access.