Heart implant may help stop strokes

WASHINGTON — At least 120,000 Americans a year suffer strokes because of a common irregular heartbeat — one that's on the rise, hard to treat and can shoot deadly blood clots straight to the brain.

Now doctors are experimenting with a new way to prevent those strokes: a tiny device that seals off a little section of the heart where the clots form.

If it works — and a major study is under way — the Watchman device might provide long-needed protection for thousands of people with atrial fibrillation, whose main hope now is a blood-thinning drug that too many can't tolerate.

"I don't think I'm biased, but it could potentially revolutionize a-fib, which is a ton of people," said Dr. Steven Almany, vice chief of cardiology at William Beaumont Hospital in Royal Oak, Mich. He has implanted the Watchman into more than a dozen patients so far.

About 2.8 million Americans have atrial fibrillation, the most common type of irregular heartbeat. It is most common among the elderly, and cases are increasing as the population ages.

Atrial fibrillation occurs when the heart's top chambers, called the atria, get out of sync with the bottom chambers' pumping. The atria speed up, and blood pools inside a pocket of the heart, allowing clots to form.

About 20 percent of the nation's strokes are blamed on this condition, and they tend to be particularly severe. About a third of the patients die, and another third are significantly disabled, Almany said.

The blood thinner warfarin, also called Coumadin, lowers the stroke risk dramatically. But it is difficult to use — it can't be taken together with dozens of other medicines, and it requires dietary restrictions and regular blood testing. In addition, side effects include serious, even life-threatening, bleeding.

By some estimates, almost half the people who should take the drug can't or won't, and "there are lots of people out there on Coumadin who want off," said Dr. William Gray, a cardiologist studying the Watchman at New York's Columbia University Medical Center. "This provides the opportunity, hopefully, to get them off the drug."

In atrial fibrillation, 90 percent of stroke-causing blood clots collect inside a jalapeño-pepper-shaped flap of tissue that hangs off the edge of the left atrium.

The Watchman physically seals off that flap, depriving clots of their staging area. The question is whether that really will stop strokes. To find out, doctors are recruiting hundreds of patients around the country to get either the experimental device or the usual Coumadin.

How does the Watchman work?

Doctors thread the mesh-covered metal brace through a leg vein up to the heart and wedge it into the opening of the troublesome flap. Tiny hooks hold it in place until heart tissue grows over it to form a permanent seal. Forty-five days after implantation, Watchman recipients have a tube put down their throats for a special heart scan to tell if the flap really is closed off. If so, they quit Coumadin.

Of the roughly 250 patients enrolled so far, 97 percent of Watchman recipients have quit the drug, Almany said. They still must be tracked for at least two years, to see how many have a stroke.

An American Stroke Association spokesman cautioned that it's far too early to know if an implant will prove a better gamble than Coumadin, a proven stroke fighter despite its risks. "I wouldn't want to raise hopes before the data is in," said Dr. Larry Goldstein, director of Duke University's stroke center.

Nor is the Watchman risk-free. The flap it blocks is very thin, posing a puncture risk as doctors hook the device in place.

"You put a hole in there, you've got a problem," said Almany.

If the Watchman ultimately works, Almany predicts the procedure could cost about $12,000, less than treating a stroke or a bad Coumadin side effect.