Factors Predicting Spontaneous Thrombosis of Aggressive Cranial Dural Arteriovenous Fistulas.

Background: Dural arteriovenous fistula (DAVF) with cortical venous drainage is known to be aggressive in clinical course and is usually managed promptly. Spontaneous resolution of DAVF is a rare phenomenon and usually occurs in benign fistulas. Spontaneous thrombosis of aggressive DAVF is an extremely rare occurrence. The present study aimed to identify the incidence and factors determining spontaneous resolution of aggressive DAVF.

Methods: All patients presenting to our institution with suspected DAVF during the study period (July 2013 to December 2015) were prospectively enrolled into a database. Different clinical, demographic, and angiographic factors were compared between the control cohort who showed spontaneous resolution and the interventional cohort who underwent endovascular intervention for definite cure. The potential determinants reported in the literature were also included in this detailed analysis.

Results: Thirty-two patients were included in the final analysis. Five patients (15.7%) showed spontaneous resolution in the follow-up period while awaiting definitive treatment. Univariate analysis showed 3 variables (DAVF architecture, thrombosis of draining vein, and transit time) to be statistically significant (P < 0.05). However, multivariate logistic regression analysis showed that only sparse fistulous network was significantly associated with acceptable outcome of spontaneous disappearance of DAVF.

Conclusions: Spontaneous thrombosis of aggressive DAVF is a known phenomenon in the natural evolution of cerebral dural arteriovenous malformation. DAVF architecture could categorize this particular subset of DAVF, which had an overall good prognosis. Further observations in large multi-institutional cohorts are needed to validate this finding and to ascertain other factors precipitating this outcome.