Stroke prevention device misses key goal in study

SAN FRANCISCO (AP) - The future is unclear for a promising heart device aimed at preventing strokes in people at high risk of them because of an irregular heartbeat.

Early results from a key study of Boston Scientific Corp.'s Watchman device suggested it is safer than previous testing found, but may not be better than a drug that is used now for preventing strokes, heart-related deaths and blood clots in people with atrial fibrillation over the long term.

More than 2.7 million Americans and 15 million people worldwide have atrial fibrillation. The upper chambers of the heart quiver instead of beating properly. That lets blood pool in a small pouch. Clots can form and travel to the brain, causing a stroke.

The usual treatment is blood thinners such as warfarin, sold as Coumadin and other brands. But they have problems of their own and some are very expensive. The Watchman is intended to be a permanent solution that would not require people to take medications for the rest of their lives. It's a tiny expandable umbrella that plugs the pouch, and is inserted without surgery, through a tube pushed into a vein.