WASHINGTON (AP) — The government has halted a study testing treatments for a brain condition that can cause strokes after early results suggested invasive therapies were riskier than previously thought.

The condition involves a kind of tangle in the brain called an arteriovenous malformation, or AVM. Arteries and veins grow knotted together until eventually some of them burst, causing a bleeding stroke. AVM accounts for a small fraction of hemorrhagic strokes.