ObjectiveCranial dural arteriovenous fistulas (dAVFs) with cortical venous drainage (CVD) (Borden type 2 and 3) are reported to carry a 15% annual risk of intracranial hemorrhage (ICH) or non-hemorrhagic neurological deficit (NHND). The purpose of this study is to compare the clinical course of type 2 and 3 dAVFs that present with ICH or NHND versus those that do not.Methods28 patients with type 2 or 3 dAVFs were retrospectively evaluated. CVD was classified as asymptomatic (aCVD) if patients presented incidentally or with pulsatile tinnitus or orbital phenomena. CVD was classified as symptomatic (sCVD) if patients presented with ICH or NHND. Occurrence of new ICH or new or worsening NHND between diagnosis and disconnection of CVD or last follow-up (if not disconnected) was noted. Overall frequency of events was compared using Fisher's exact test. Cumulative event free survival was compared using Kaplan–Meier analysis with log rank testing.ResultsOf 17 patients with aCVD, one (5.9%) developed ICH and none experienced NHND or death during the mean 4.1 years of follow-up. Of 11 patients with sCVD, two (18.2%) developed ICH and three (27.3%) suffered new or worsened NHND over the mean 2.4 years of follow-up. One of these patients subsequently died. Overall frequency of ICH or NHND was significantly lower in patients with aCVD versus sCVD (p=0.022). Respective annual event rates were 1.4% versus 19.0%. aCVD patients had significantly higher cumulative event free survival (p=0.0016).ConclusionCranial dAVFs with aCVD may have a less aggressive clinical course than those with sCVD.

Object The goal of this study was to determine the clinical course of Borden-Shucart Type I cranial dural arteriovenous fistulas (DAVFs) and to calculate the annual rate of conversion of these lesions to more aggressive fistulas that have cortical venous drainage (CVD). Methods A retrospective chart review was conducted of all patients harboring DAVFs who were seen at the authors' institution between 1997 and 2009. Twenty-three patients with Type I DAVFs who had available clinical follow-up were identified. Angiographic and clinical data from these patients were reviewed. Neurological outcome and status of presenting symptoms were assessed during long-term follow-up. Results Of the 23 patients, 13 underwent endovascular treatment for intolerable tinnitus or ophthalmological symptoms, and 10 did not undergo treatment. Three untreated patients died of unrelated causes. In those who were treated, complete DAVF obliteration was achieved in 4 patients, and palliative reduction in DAVF flow was achieved in 9 patients. Of the 19 patients without radiographic cure, no patient developed intracranial hemorrhage or nonhemorrhagic neurological deficits (NHNDs), and no patient died of DAVF-related causes over a mean follow-up of 5.6 years. One patient experienced a spontaneous, asymptomatic obliteration of a partially treated DAVF in late follow-up, and 2 patients experienced a symptomatic conversion of their DAVF to a higher-grade fistula with CVD in late follow-up. The annual rate of conversion to a higher-grade DAVF based on Kaplan-Meier cumulative event-free survival analysis was 1.0%. The annual rate of intracranial hemorrhage, NHND, and DAVF-related death was 0.0%. Conclusions 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.

Spontaneous isolated convexity SAH is rarely caused by aneurysm rupture, has a distinct mode of presentation, and generally carries a more favorable prognosis than that of aneurysmal SAH.

Cranial dAVFs with aCVD may have a less aggressive clinical course than those with sCVD.