Interventional treatments such as surgery provide good functional outcomes and a high cure rate for patients with lower-grade arteriovenous malformations (AVMs) of the brain, according to a new study. These findings contrast with a recent trial reporting better outcomes without surgery or other interventions for AVMs.

The researchers evaluated their hospital's experience in treating 105 patients with AVMs from 2005 to 2012. Arteriovenous malformations are congenital defects consisting of an abnormal tangle of blood vessels. When AVMs are located in the brain, there is a risk that they may rupture and bleed, causing potentially life-threatening hemorrhagic stroke. When AVMs are detected before rupture, options include medical (conservative) treatment, consisting of monitoring and follow-up; or various active treatments, including surgery, an interventional procedure called embolization, or a radiation procedure called radiosurgery. 

Yet in the 2014 ARUBA clinical trial, patients randomly assigned to medical treatment had a lower three-year risk of stroke or death, compared to those undergoing other surgery or other interventions.

The new analysis focused on 61 adult patients with brain AVMs who would have been eligible for the ARUBA study. Researchers categorized the results by AVM severity: low-grade, intermediate, or high-grade. About half of the ARUBA-eligible patients had low-grade (grade I or II) AVMs. Most were treated with a combination of embolization and surgery or with radiosurgery.

At an average follow-up of two years, all outcomes were better for patients with lower-grade AVMs. Based on the same scale used in ARUBA, the rate of functional impairment was three percent in patients with grade I/II AVMs, compared with 20 to 25 percent for those with intermediate or high-grade AVMs. Overall, 22 patients with low-grade AVMs were treated with surgery, usually after embolization. At their last follow-up, all 22 patients had normal functional status and "radiographic cure," with no remaining signs of AVM on brain imaging scans. The cure rate was higher with surgery than with radiosurgery.

The new findings "challenge the assertion that medical management is superior" to surgery or interventional treatments for unruptured brain AVMs, the authors write.

Citation: "Treatment Outcomes of Unruptured Arteriovenous Malformations With a Subgroup Analysis of ARUBA (A Randomized Trial of Unruptured Brain Arteriovenous Malformations)-Eligible Patients" doi: 10.1227/NEU.0000000000000663