Response to Letter Regarding Article, “Intracranial Dural Arteriovenous Fistulae: Clinical Presentation and Management Strategies”

Abstract

We thank Gross and Du 1 for their comments on our recent review of dural arteriovenous fistula (DAVF). 2 We disagree with their suggestion that meningeal vessels exclusively supply DAVFs. Although pial supply is rare, we have observed it on several occasions, and it has been described in the literature. 3 We recognize the contributions made by Houser et al and Djindjian in the identification of cortical venous drainage (CVD) as a risk factor for hemorrhage associated with DAVF. However, the aim of our article was not to provide an historical overview of the development of our modern understanding of these lesions. We highlighted the report by Malik et al 4 because they had also performed a fairly extensive meta-analysis of 27 previously published cases of DAVF associated with hemorrhage (out of a total of 213 lesions), putting into perspective the risk posed by CVD in a larger patient population.As we emphasized in our article, reported annualized rates of hemorrhage, nonhemorrhagic deficits, and mortality from DAVF with CVD have varied considerably in the literature. We agree with Gross and Du 1 that this variability probably reflects heterogeneity in the population of DAVF's included in individual reports. Consequently, we felt that reporting single, averaged, annualized rates for these sequelae may be misleading, and instead opted to describe the findings of 3 representative studies. We would like to point out that the 6% annual hemorrhage rate of DAVF with CVD cited by Gross and Du 1 is well within the range that we present in our review (4%-19%).We agree with Gross and Du 1 that aggressive clinical presentation and venous ectasia are risk factors for DAVF-associated hemorrhage. In our article, we emphasized that lesions with CVD often have more aggressive clinical presentations, and we provided Cognard classification system of DAVF, which highlights venous ectasia. However, the key factor determining management of DAVF remains the presence or the absence of CVD. On the basis of our review of the literature and current understanding of the natural history of aggressive DAVF, patients with fistula demonstrating CVD, even if they are asymptomatic, or do not have associated venous ectasia, should be offered treatment.In our review, we clearly state the limitations of the article by Narvid et al, 5 which evaluated the ability of computed tomography angiography to detect arterial feeders of DAVF. It is important to note that cross-sectional imaging techniques have made tremendous strides over the last several years, and they can be a reasonable screening study in low-risk patients (eg, those presenting with pulsatile tinnitus). However, catheter angiography maintains its place as the imaging gold standard and should be performed if the clinical suspicion for DAVF is high.We stand by the statement that a majority of intracranial DAVF may be cured by modern endovascular methods, with few lesions lacking a safe route of transarterial or transvenous access. To the best of our knowledge, multidisciplinary groups often...

Unique percutaneous direct puncture technique for occlusion of a hypoglossal canal dural arteriovenous fistula

“…As was true in our case, Miller1 points out that ‘in contradistinction to cerebral arteriovenous malformations, obliteration of DAVFs may be accomplished by occlusion of the fistula’s draining vein(s)'. In patients with DAVFs with multiple arterial feeders and multiple draining veins, CBCT provides an excellent tool for identifying the exact site of the fistula as well as an access route to a dominant outflow vein for embolization.…”

“…DAVFs account for 10–15% of intracranial vascular malformations and 35% of those occur in the posterior fossa 1. They are seen most commonly in men in their 50s.…”

“…The standard approach for management of DAVFs is transvenous and/or transarterial embolization. Surgery is usually reserved for residual fistulous communications 1. The posterior fossa DAVF in our case falls into the subset of DAVFs with involvement of the anterior condylar/hypoglossal vein (ACV) 2–13.…”

Accelerated Time-Resolved Contrast-Enhanced Magnetic Resonance Angiography of Dural Arteriovenous Fistulas Using Highly Constrained Reconstruction of Sparse Cerebrovascular Data Sets

“…Vascular imaging plays a key role in establishing the diagnosis and excluding other etiologies for the patient’s symptoms. (1, 2) Imaging of the DAVF venous drainage is particularly important because DAVFs with cortical venous drainage (CVD) can behave aggressively with annual rates of neurologic deficit of 7 - 30%, intracranial hemorrhage of 4.5 - 35%, and mortality of 11 - 45%. (2-7) Thus, vascular imaging aids in DAVF risk stratification by identifying the arterial supply and delineating the venous drainage.…”

The application of susceptibility-weighted MRI in pre-interventional evaluation of intracranial dural arteriovenous fistulas

“…Intracranial dural arteriovenous fistulas (DAVFs) are uncommon neurovascular diseases which account for approximately 10–15% of all intracranial arteriovenous lesions 1. Studies on the natural history of these lesions have noted the relationship of the clinical symptoms with patterns of venous drainage 2–4.…”