Long-term treatment outcome of venous-predominant arteriovenous malformation

OBJECTIVE Treatment strategies for venous-predominant arteriovenous malformation (vp-AVM) remain unclear due to the limited number of cases and a lack of long-term outcomes. The purpose of this study was to report the authors' experience with treatment outcomes with a review of the pertinent literature in patients with vp-AVM. METHODS Medical and radiological data from 1998 to 2011 were retrospectively evaluated. The degree of the arteriovenous (AV) shunt was categorized into 2 groups, a high- and low-flow AV shunt based on the angiographic findings. RESULTS Sixteen patients with a mean age of 45.3 years (range 16-78 years) and a mean follow-up of 79.9 months (range 25-264 months) were examined. Symptomatic lesions were noted in 13 patients: intracranial hemorrhage (ICH) in 9, seizure in 1, and headache in 3. A high-flow shunt was observed on angiography in 13 patients. Among these 13 patients, 12 patients were symptomatic. Nine patients presenting with ICH underwent hematoma removal with additional Gamma Knife surgery (GKS; n = 4), GKS only (n = 2), or conservative treatment (n = 3). The 3 asymptomatic patients received conservative treatment, and 1 rebleeding episode was observed. Seven of 8 patients who underwent GKS as an initial or secondary treatment modality experienced a marked reduction in the AV shunt on follow-up angiography, but complete obliteration was not observed. CONCLUSIONS Poor lesion localization makes a vp-AVM challenging to treat. Symptomatic patients with a high-flow shunt are supposedly best treated with GKS, despite the fact that only 87.5% of the vp-AVMs treated this way showed a reduction in the malformation volume, and none were cured.