Correlation of Aggressive Intracranial Lesions and Venous Reflux Patterns in Dural Arteriovenous Fistulas.

BACKGROUND: The association between venous reflux patterns with aggressive intracranial lesions (AILs), including intracranial edema (IE), intraparenphymal hemorrhage (IPH), and subarachnoid hemorrhage (SAH), has not been well established in cranial dural arteriovenous fistulas (DAVFs). We propose an updated classification system based on venous drainage. METHODS: We retrospectively assessed the catheter angiography findings of venous drainage patterns. Cranial DAVFs with no reflux flow and those with reflux flow drainage into the sinus only, the bridge vein only, the bridge vein and pial vein, and the sinus, bridge vein, and pial vein were designated as types 1, 2, 3, 4, and 5, respectively. We analyzed the associations between venous reflux patterns with AILs in 73 patients with DAVFs. RESULTS: AILs were found in 43 patients (58.9%), including 8 (11%) with SAH, 8 (11%) with IPH, and 27 (36.9%) with IE. Our proposed classification scheme was significantly associated with AILs (P < 0.001). SAH was found in patients with type 3 (62.5%) and type 4 (37.5%), whereas IPH was seen mostly in those with type 4 (87.5%). The proportion of IE gradually increased from type 3 to type 5 (11.1% to 29.6% to 59.2%). Significant difference was found among each type between complete resolution and uncompleted resolution after endovascular treatment (P = 0.034), which also demonstrated a gradually increasing proportion of uncompleted resolution from type 1 to type 5 (4.5%, 4.5%, 9.1%, 31.8%, and 50%). CONCLUSIONS: Our proposed classification system effectively demonstrates a correlation between venous reflux patterns and AILs and outcomes of endovascular treatment in patients with DAVFs.