A review of dural arteriovenous fistulas with hemorrhagic onset

Abstract The majority of dural arteriovenous fistulas are considered to have a benign clinical course, but some behave more aggressively, causing progressive neurological symptoms and/or intracranial hemorrhage. Several classifications of angiographic findings have been reported to predict what findings might result in catastrophic presentation. Cortical venous drainage has been described as one of the major risk factors of hemorrhage. We reviewed the records of 50 patients with dural arteriovenous fistulas admitted to our institution from 1991 to 2001 and analyzed their venous drainage patterns with reference to Cognard's classification. Six patients had hemorrhagic episodes caused by dural arteriovenous fistula and all of them had retrograde drainage through cerebral veins. The frequency of hemorrhage in Type I and IIa was 0%, in Type IIb it was 33.3%, in Type IIa + b it was 9.1%, in Type III and Type IV it was 50%, and in Type V it was 100%. These results agreed with those of Cognard reported in 1994, and we reconfirmed the usefulness of Cognard's classification. In order to adapt a firm strategy and treat them promptly and aggressively, it is important to be able to recognize what type of dural arteriovenous fistulas are perilous.