Widely used drug prevents strokes.

A common anticlotting drug could be the key to preventing 40,000 strokes a year. Results from a government-sponsored study of patient records show that the anticoagulant warfarin--sold under the brand name Coumadin--successfully prevents strokes in people with rapid, irregular heartbeats.

While physicians have known that anticoagulant therapy helps to prevent some types of strokes, the finding, announced on Sept. 7 by the Agency for Health Care Policy and Research, an arm of the U.S. Public Health Service in Rockville, Md., emphasizes the drug's beneficial role for people suffering from a condition known as atrial fibrillation (AF).

"Warfarin can reduce a person's risk for stroke by 50 percent, yet fewer than half of the people who are eligible for anticoagulation therapy [receive it]," says study leader David B. Matchar of Duke University in Durham, N.C.

More than half a million Americans suffer strokes each year. A stroke occurs when narrowed blood vessels, blood clots, or bleeding in the brain deprives the brain of oxygen and nutrients. Strokes constitute the third leading cause of death in the United States, and survivors often suffer loss of vision, speech problems, and difficulties in walking.

Many strokes could be prevented, physicians agree, if people stopped smoking and took steps to control high blood pressure. However, nearly 5 percent of Americans over age 65 suffer from AF--a fast, erratic beat in the upper left chamber of the heart that causes blood to pool in the chamber and clot. People with AF run an increased risk of stroke from these clots.

Physicians have refrained from widespread use of warfarin to prevent stroke, Matchar says, because the drug can cause severe bleeding. Since there's no way to tell which patients will suffer strokes, many doctors questioned whether warfarin's ability to prevent stroke outweighed the risks of taking it. Moreover, each person requires an individual dosage schedule and monthly monitoring.

Matchar and his colleagues on the federal stroke prevention study examined records from eight centers across the country and found that "for every one person who suffers a serious bleeding complication, warfarin prevents 20 strokes and deaths," says Matchar.

The finding was so dramatic that the federal agency took the unusual step of announcing its results early. The warfarin work represents only one aspect of the overall study, which is designed to test a variety of methods for preventing strokes of all kinds.

Clifton R. Gaus, an administrator at the agency, says that caring for stroke victims costs an estimated $30 billion a year. Giving AF patients anticoagulants would reduce health care costs by some $600 million a year, he notes.

Roger L. Weir of Howard University College of Medicine in Washington, D.C., who represents the American Heart Association, points out that warfarin requires careful monitoring to prevent serious bleeding complications. Matchar agrees but notes that nurse practitioners, physician assistants, and nurses could provide appropriate monitoring under a physician's supervision.