Evaluation of stereotactic radiosurgery for cerebral dural arteriovenous fistulas in a multicenter international consortium

Abstract

Objective: In this multicenter study, the authors reviewed the results obtained in patients who underwent Gamma Knife radiosurgery (GKRS) for dural arteriovenous fistulas (dAVFs) and determined predictors of outcome.

Methods: Data from a cohort of 114 patients who underwent GKRS for cerebral dAVFs were compiled from the International Gamma Knife Research Foundation. Favorable outcome was defined as dAVF obliteration and no posttreatment hemorrhage or permanent symptomatic radiation-induced complications. Patient and dAVF characteristics were assessed to determine predictors of outcome in a multivariate logistic regression analysis; dAVF-free obliteration was calculated in a competing-risk survival analysis; and Youden indices were used to determine optimal radiosurgical dose.

Results: A mean margin dose of 21.8 Gy was delivered. The mean follow-up duration was 4 years (range 0.5-18 years). The overall obliteration rate was 68.4%. The postradiosurgery actuarial rates of obliteration at 3, 5, 7, and 10 years were 41.3%, 61.1%, 70.1%, and 82.0%, respectively. Post-GRKS hemorrhage occurred in 4 patients (annual risk of 0.9%). Radiation-induced imaging changes occurred in 10.4% of patients; 5.2% were symptomatic, and 3.5% had permanent deficits. Favorable outcome was achieved in 63.2% of patients. Patients with middle fossa and tentorial dAVFs (OR 2.4, p = 0.048) and those receiving a margin dose greater than 23 Gy (OR 2.6, p = 0.030) were less likely to achieve a favorable outcome. Commonly used grading scales (e.g., Borden and Cognard) were not predictive of outcome. Female sex (OR 1.7, p = 0.03), absent venous ectasia (OR 3.4, p < 0.001), and cavernous carotid location (OR 2.1, p = 0.019) were predictors of GKRS-induced dAVF obliteration.

Conclusions: GKRS for cerebral dAVFs achieved obliteration and avoided permanent complications in the majority of patients. Those with cavernous carotid location and no venous ectasia were more likely to have fistula obliteration following radiosurgery. Commonly used grading scales were not reliable predictors of outcome following radiosurgery.

Keywords: C-dAVF = cavernous dAVF; CVD = cortical venous drainage; GKRS = Gamma Knife radiosurgery; Gamma Knife; ICH = intracerebral hemorrhage; RIC = radiation-induced complication; SAH = subarachnoid hemorrhage; arteriovenous; dAVF = dural arteriovenous fistula; dural; fistula; outcome; stereotactic radiosurgery; vascular disorders.

FIG. 1.

Kaplan-Meier plot of overall dAVF obliteration over time. The postradiosurgery actuarial rates of obliteration at 3, 5, 7, and 10 years were 41.3%, 61.1%, 70.1%, and 82.0%, respectively. Values at the bottom of the figure correspond to the number of patients available for each follow-up interval (114 for 2 years, 81 for 4 years, and so on).

FIG. 2.

Kaplan-Meier plot of dAVF obliterations over time stratified by predictive factor. The postradiosurgery Kaplan-Meier plots of obliteration stratified by sex (A), cavernous carotid fistula location (CCF) and noncavernous location (No-CCF) (B), and the presence of venous ectasia (VE) and the absence of venous ectasia (No-VE) (C). Values at the bottom of each panel correspond to the number of male and female patients (A), the number of patients with noncavernous dAVFs (NC-dAVFs) and C-dAVFs (B), and the number of patients without venous ectasia and with venous ectasia (C) available for each follow-up interval (66 males and 48 females at 2 months [A], 95 NC-dAVFs and 19 C-dAVFs at 2 months [B], and 91 patients without venous ectasia and 23 patients with venous ectasia at 2 months [C], and so on).