The blood thinner Plavix, when combined with aspirin, appears to prevent strokes and heart attacks in people with a common heartbeat abnormality called atrial fibrillation, doctors report.
In patients with atrial fibrillation, disorganized electrical signals in the heart's two upper chambers, called the atria, cause the chambers to contract irregularly. As a result, blood isn't pumped completely into the heart's two lower chambers and tends to pools in the atria where it can begin to clot. These clots can then travel to the brain, causing a stroke.
The usual medication given to those with atrial fibrillation is the blood thinner warfarin. But finding the right dose is tricky; if a patient takes too much, it can lead to uncontrolled bleeding; too little and the risk of blood clots returns.
Patients on the drug must go to labs often for tests to monitor their dosage.
Aspirin is an option, but sometimes only modestly effective when taken alone.
Dr. Stuart Connolly of McMaster University in Hamilton, Ont. led a study testing whether adding clopidogrel, sold as Plavix, could help. Plavix's manufacturer, Sanofi-Aventis, funded the study.
The study involved 7,554 patients in the United States and 32 other countries who were not able, or chose not, to take warfarin. All were treated with aspirin; half also were given clopidogrel.
After nearly four years, the clopidogrel-aspirin dual drug treatment group had 11 per cent fewer cardiac events -- including heart attacks, strokes and blood clots -- compared with those taking aspirin alone.
"The real exciting news was stroke was reduced by 28 per cent," said Connolly, who presented the study Tuesday at the American College of Cardiology scientific meeting in Orlando.
However, the Plavix-aspirin combination raised the risk of serious bleeding -- 251 cases versus 162 for those on aspirin alone.
Nevertheless, the increase in bleeding risk was still less than what can be expected from the standard warfarin treatment, the researchers said.
Dr. Richard Page, cardiology chief at the University of Washington School of Medicine in Seattle and an American Heart Association spokesman said warfarin remains first-line therapy
"This does not change that," he said. But for those patients who can't tolerate warfarin, this combo gives a better option than aspirin alone, he said.
Dr. Aaron Kugelmass, the chair of this year's cardiology conference and chief of cardiology at Baystate Medical Center in Massachusetts, said the Plavix/aspirin combination will become an alternative for those patients with atrial fibrillation who are at high risk of stroke and are unsuitable for warfarin.
"I suspect people will start adopting this approach for patients who are ineligible for warfarin," said Kugelmass.
The results are published online by the New England Journal of Medicine.
