Borden type I intracranial dural arteriovenous fistula
Type I dural arteriovenous fistulas are supplied by a meningeal artery or arteries and drain into a meningeal vein or dural venous sinus. The flow within the draining vein or venous sinus is anterograde.
Type Ia – simple dural arteriovenous fistulas have a single meningeal arterial supply
Type Ib – more complex arteriovenous fistulas are supplied by multiple meningeal arteries The distinction between Types Ia and Ib is somewhat specious as there is a rich system of meningeal arterial collaterals. Type I dural fistulas are often asymptomatic, do not have a high risk of bleeding and do not necessarily need to be treated
A small number of Type I DAVFs will convert to more aggressive DAVFs with CVD over time. This conversion to a higher-grade DAVF is typically heralded by a change in patient symptoms. Follow-up vascular imaging is important, particularly in the setting of recurrent or new symptoms. 3).
A comparative meta-analysis was completed to evaluate the outcomes of intervention versus observation of Borden type I intracranial dural arteriovenous fistula. Outcome measures included: grade progression, worsening symptoms, death due to dural arteriovenous fistula, permanent complications other than death, functional independence (mRS 0-2), and rate of death combined with permanent complication, were evaluated. Risk differences (RD) were determined using a random effects model.
Three comparative studies combined with the authors’ institutional experience resulted in a total of 469 patients, with 279 patients who underwent intervention and 190 who were observed. There was no significant difference in dAVF grade progression between the intervention and observation arms, 1.8% vs. 0.7%, respectively (RD: 0.01, 95% CI: -0.02 to 0.04, P = 0.49), or in symptom progression occurring in 31/279 (11.1%) intervention patients and 11/190 (5.8%) observation patients (RD: 0.03, CI: -0.02 to 0.09, P = 0.28). There was also no significant difference in functional independence on follow-up. However, there was a significantly higher risk of dAVF-related death, permanent complications from either intervention or dAVF-related ICH or stroke in the intervention group (11/279, 3.9%) compared to the observation group (0/190, 0%) (RD: 0.04, CI: 0.1 to 0.06, P = 0.007).
CoIntervention of Borden Type I dAVF results in a higher risk of death or permanent complication, which should be strongly considered when deciding on the management of these lesions 4).
From April 2013 to March 2016, consecutive patients with DAVF were screened at 13 study institutions. We collected data on baseline characteristics, clinical symptoms, angiography, and neuroimaging. Patients with Borden type I DAVF received conservative care while palliative intervention was considered when the neurological symptoms were intolerable, and were followed at 6, 12, 24, and 36 months after inclusion.
Results: During the study period, 110 patients with intracranial DAVF were screened and 28 patients with Borden type I DAVF were prospectively followed. None of the patients had conversion to higher type of Borden classification or intracranial hemorrhage during follow-up. Five patients showed spontaneous improvement or disappearance of neurological symptoms (5/28, 17.9%), and 5 patients showed a spontaneous decrease or disappearance of shunt flow on imaging during follow-up (5/28, 17.9%). Stenosis or occlusion of the draining sinuses on initial angiography was significantly associated with shunt flow reduction during follow-up (80.0% vs 21.7%, p = 0.02).
Conclusion: In this 3-year prospective study, patients with Borden type I DAVF showed benign clinical course; none of these patients experienced conversion to higher type of Borden classification or intracranial hemorrhage. The restrictive changes of the draining sinuses at initial diagnosis might be an imaging biomarker for future shunt flow reduction 5)