Cortical Drainage Directly Into a Sinus Versus Drainage With Angiographic Parenchymal Venous Reflux: Improved Stratification of “High-Risk” Dural Arteriovenous Fistulas

BACKGROUND AND OBJECTIVES: While cortical venous drainage (CVD) is recognized as a high-risk angiographic feature for dural arteriovenous fistulas (dAVFs), the drainage pattern itself is not well scrutinized. In this study, we sought to delineate the prevalence, clinical presentation, and untreated course of dAVFs with parenchymal venous reflux (PVR) from CVD vs those draining into cortical veins that more simply drain directly into a venous sinus. METHODS: An institutional database was queried for demographical, angiographic data and the untreated course of dAVFs with direct CVD (Cognard type III or IV). Clinical presentation and annualized risk of new intracranial hemorrhage (ICH) or nonhemorrhagic neurological deficit (NHND) were stratified by the presence or lack of PVR. Multivariate logistic regression or Cox proportional hazards regression were used to delineate the impact of PVR on presentation modality or untreated course. RESULTS: Of 128 dAVFs with direct CVD, 61% had angiographic PVR and 55% presented with ICH/NHND. The presence of PVR was associated with a 7-fold increased risk (95% CI 3.11-18.32, P < .001) and an 80% sensitivity for aggressive presentation (ICH/NHND). Annualized ICH/NHND rates were 31.6% in the PVR group and 2.4% in the no-PVR group (log-rank P = .008) over the untreated follow-up period. CONCLUSION: Angiographic PVR is associated with a greater risk of ICH/NHND on presentation and over follow-up, suggesting it may serve as an indicator of clinically more significant venous hypertension.