New drug may cut risk of stroke by one-third

People at risk of stroke may, for the first time, be offered a potentially superior alternative to the blood-thinning drug warfarin, following the publication of a major drugs trial yesterday.

The RE-LY study compared the effectiveness of warfarin with a new drug, dabigatran, in over 18,000 people at risk of having a stroke due to a common heart rhythm condition called atrial fibrillation.

The Canadian-led researchers found dabigatran reduced the risk of stroke by 34 per cent compared to patients taking warfarin, without increasing the risk of major bleeding.

The results, published online by the New England Journal of Medicine and presented to the European Society of Cardiology Congress in Barcelona yesterday, suggest doctors will be able to offer patients an alternative to warfarin, which is highly effective within a narrow dose range, but requires regular monitoring to check its effectiveness and to prevent the risk of unwanted bleeding.

According to Professor Stuart Connolly, director of the Division of Cardiology at McMaster University in Canada, a lead investigator of the study, “several new drugs have been recently studied to see if they could replace warfarin. None, however, has been satisfactory.”

“Either they were not effective enough, they had too many side- effects or they caused too much bleeding.

“This is the first time in more than 50 years that a new oral blood thinner has been developed which has been found to be both safer and more effective than existing therapy,” said Dr Connolly.

Atrial fibrillation is the most common heart rhythm condition, affecting about 1 per cent of the total population, rising to 10 per cent in people over the age of 80.

People with the condition have an increased risk of blood clots, which in turn raises the risk of developing a stroke. About one in six strokes are caused by atrial fibrillation.

The RE-LY study was carried out in more than 951 centres in 44 countries. Patients were enrolled over a two-year period and followed up for one further year.

The results found a higher dose of dabigatran (marketed under the trade name Pradaxa), at 150 mg twice daily, significantly reduced the risk of stroke by 34 per cent compared to warfarin.

The lower dose, 110 mg twice daily, had a similar effect to warfarin in the prevention of stroke, but with significantly less major bleeding.

Source : www.irishtimes.com

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Window for Stroke Treatment Opens Wider

A new analysis showing that a potent clot-dissolving drug can safely be used to treat strokes four-and-a-half hours after symptoms begin has prompted a change in a current recommendation, which set a three-hour deadline for the medication's use.

The review of 1,622 cases of people treated with tissue plasminogen activator (tPA) in four separate studies finds that the benefit in keeping brain cells alive outweighs the risk of brain-damaging bleeding when the drug is given up to 4.5 hours after first symptoms, according to a report in the May 28 online issue of Stroke. The most convincing results came from the latest study, in which 821 people were treated later than is currently recommended.

"By pooling data from four prior clinical trials in which patients were treated with tPA between three and four-and-a-half hours, we were able to demonstrate that treatment with tPA is beneficial even if it is started between three and four-and-a-half hours of symptom onset," said study author Dr. Maarten Lansberg, an assistant professor of neurology and neurological sciences at Stanford University.

An advisory committee of the American Stroke Association/American Heart Association (ASA/AHA) promptly issued a recommendation that the window for tPA therapy be opened that much wider; that advisory appears in the same issue of Stroke.

"The advisory updates the current guidelines to recommend treatment in select patients in the three- to four-and-a-half hour window, but urges confirmation of the trial's results with further analyses," according to a statement issued by the ASA/AHA.

"In practical terms, wide adoption of the recommendation would mean that 2 percent to 3 percent more people who suffer strokes caused by blockage of a brain artery would receive tPA therapy," said Dr. Jeffrey L. Saver, professor of neurology at the University of California, Los Angeles, and a member of the advisory committee.

That might not seem a great leap forward, but Saver noted that "right now, at well-performing hospitals, 5 to 10 percent of stroke patients are treated in under three hours."

"That disappointing number is due primarily to the widespread failure of people to know the symptoms of a stroke and take immediate action when they are seen," he said.

"This re-emphasizes that what we need to highlight for the public is the importance of getting aid as soon as symptoms begin," Saver said. "Therapy with tPA is most effective when given in the first hour. One hour is better than two, two is better than three, three is better than four. Should there be weakness on one side of the body, trouble speaking, trouble with vision, if any of those signs occur, call 911 at once."

The chief concern with tPA is that it might cause excess bleeding that damages the brain, Saver said. But data cited in the new study show that "for every 100 patients treated with tPA between three and four-and-a-half hours after symptoms, 16 will have a better outcome, and two or three will have a worse outcome," he said. "The treatment has risks, but we help six patients for every one we harm."

The benefit is seen in the 80 percent to 85 percent of strokes caused by an artery blockage. Treatment with tPA is not recommended for the 10 percent to 15 percent of strokes that are caused by a burst brain vessel.

The U.S. Food and Drug Administration set a three-hour limit on use of tPA in strokes when it was approved 13 years ago, Saver noted. "Now we have the first expansion of guidelines for giving a clot-dissolving drug, so it is an important advance in stroke care," he said.

But tPA should not be used beyond the three-hour limit in a number of cases, the advisory committee said -- people aged 80 and older, those having a severe stroke, those with a history of stroke and diabetes and those taking clot-preventing drugs such as Coumadin.

For anyone who has a stroke, "time lost is brain lost," Saver said. "Every minute, 2 million neurons die. What we want to see is door to needle time of 60 minutes."

Source : www.bio-medicine.org

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