Abstract 125: Observation versus Treatment for Low-Grade Intracranial Dural Arteriovenous Fistulas: A Multicenter Matched Cohort Study

Abstract

Background and Purpose: Given the benign natural history of intracranial low-grade dural arteriovenous fistulas (dAVFs), their routine treatment remains controversial. The aim of this study is to compare the outcomes of low-grade dAVF treatment to conservative management. Methods: We performed a retrospective review of dAVF patients derived from 12 institutions participating in the Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR). Patients with low-grade (Borden I) dAVFs were included and categorized into treatment and observation cohorts. Primary outcome was defined as modified Rankin Scale (mRS) score at final follow-up. Secondary outcomes were rates of excellent (mRS 0-1) and good (mRS 0-2) functional outcomes, symptomatic improvement, mortality, and obliteration at final follow-up. Results: The treatment and observation cohorts comprised 230 and 112 patients, respectively. At last follow up, no difference in primary or secondary outcomes was observed between the two cohorts, with the exception of obliteration, which was higher in the treatment cohort (79.3% vs. 28.2%, p<0.001; Table 1). The two cohorts were then matched in a 1:1 ratio, resulting in 64 patients in each matched cohort. No difference in primary or secondary outcomes was observed between the matched cohorts, with the exception of obliteration, which was higher in the matched treatment cohort (75.4% vs. 28.6%, p<0.001; Table 2). Subgroup analysis of symptomatic patients demonstrated higher obliteration rate in the treatment cohort, but no difference in primary or other secondary outcomes were found. Conclusions: Low-grade dAVF treatment was not associated with increased functional disability compared to conservative management. Although higher obliteration rates were achieved in the treatment cohort, rates of symptomatic improvement were similar between the two cohorts. This study did not provide evidence to support the routine treatment of low-grade dAVFs.