Low- and Intermediate-Grade Lateral Sinus Dural Arteriovenous Fistulas: Factors Affecting the Outcome of Endovascular Treatment over 18-Year Experience in a High-Volume Neurovascular Center.

Background and purpose: Lateral sinus dural arteriovenous fistulas (LS-DAVFs) carry a higher rate of recurrence after endovascular treatment (EVT). Our objective was to investigate the independent predictors of recurrence and unfavorable functional outcomes of low-and intermediate-grade LS-DAVFs after EVT.

Materials and methods: We retrospectively reviewed our database of prospectively collected information for all patients with low- and intermediate-grade LS-DAVFs who underwent EVT from May 2004 to December 2021. Patient demographics, angiographics, treatment, and outcomes were analyzed to identify independent predictors of recurrence and unfavorable outcomes.

Results: One hundred and seventeen patients with 117 low- and intermediate-grade LS-DAVFs who underwent EVT were included in this study. The mean age of the patients was 53.0 ± 17.5 years. Immediately complete obliteration was achieved in 103/117 (88%) patients after EVT. Clinical follow-up was available for all 117 patients, with an unfavorable outcome rate of 5.1%. Angiographic follow-up was available in 91 patients (78%). Recurrence occurred in 16 (18%) patients and 8 (6.8%) received retreatment. Contralateral sinus severe stenosis or occlusion was an independent high-risk factor for the unfavorable outcome (OR = 11.7; 95% CI: 1.9-70.9, P < .01) and recurrence (OR = 63.8; 95% CI: 10.3-396.5, P < .01) for low- and intermediate-grade LS-DAVFs at follow-up.

Conclusions: Contralateral sinus severe stenosis or occlusion represents a stronger independent risk factor associated with recurrence and unfavorable outcomes in patients with low- and intermediate-grade LS-DAVFs when the involved ipsilateral sinus was occluded after EVT. For patients with LS-DAVFs, the patency of the contralateral sinus should be considered when making therapeutic decisions.