Many stroke patients have a new treatment option-- if they seek help fast enough to get it. New guidelines endorse using a removable stent to open clogged arteries causing a stroke.

The guidelines, issued Monday by the American Heart Association, are the first time the group has recommended a device for treating strokes, and it's the first new stroke treatment in two decades to win the group's strongest backing. The federal government no longer issues guidelines like these, so the Heart Association's advice clears the way for more doctors to offer the treatment.

"It is pretty exciting," and many patients will benefit if they seek help when symptoms first appear, said the head of the guidelines panel, Dr. William J. Powers, neurology chief at the University of North Carolina at Chapel Hill.

Most of the 800,000 strokes in the U.S. each year are caused by a blood clot lodged in the brain. The usual treatment is a clot-dissolving medicine called tPA, and it remains the first choice.

But the drug must be given within 4 1/2 hours after symptoms start, and most people don't seek help in time. The drug also fails to work in one or two of every four cases, Powers said.

The device is called a stent retriever. It's a tiny mesh cage that is pushed through a tube into a blood vessel and guided to the clot, like the stents long used to treat blocked heart arteries. But unlike heart stents, which are left in place to prop the artery open, brain stents trap the clot and are removed with it.

Earlier this year, several major studies found these devices dramatically cut the risk of death or disability in people whose clots persisted after treatment with tPA.

The guidelines say these patients now can be treated with a stent retriever if it can be done within six hours of symptom onset, they have a severe stroke caused by a clot in a large artery, and have brain imaging showing that at least half of the brain on the side of the stroke is not permanently damaged.

The benefit of stent retrievers beyond six hours, or for people not treated first with tPA, is unknown.

"We think it probably works in some of them but we just don't have the hard evidence" to recommend it, Powers said.

Where patients seek help matters. Only major stroke centers can do the technically difficult procedure with stent retrievers.

Two brands are sold in the U.S. - Trevo, made by Stryker Corp. of Kalamazoo, Michigan, and Solitaire, made by Covidien, now part of Minneapolis-based Medtronic Inc.

Medtronic and Covidien help sponsor an American Heart Association/American Stroke Association program aimed at helping people recognize stroke symptoms - sudden onset of any of these: numbness or weakness on one side, severe headache with no known cause, confusion, and trouble walking, speaking or seeing.

But the companies had no role in shaping the guidelines. Two of the 19 experts involved in the guidelines have consulted for device makers.