Nov. 4 (Bloomberg) -- Sanofi-Aventis SA and Bristol-Myers Squibb Co.'s blood thinner Plavix may save thousands of lives each year if doctors add it to aspirin for the emergency treatment of heart attacks, according to a new study published in tomorrow's issue of The Lancet.

Adding Plavix, or clopidogrel, to aspirin cut the relative risk of deaths, repeated heart attacks and stroke by 9 percent compared with placebo, and led to a 7 percent reduction in deaths alone, said Zheng-Ming Chen from the University of Oxford, England, who recruited more than 45,800 patients from 1,250 hospitals in China.

Plavix, first introduced in 1997 to prevent blood cells known as platelets from sticking together and clotting, had sales of 1.7 billion euros ($2 billion) last year. Giving the drug to about 1 million of the 10 million patients who have a heart attack every year would prevent about 5,000 deaths and 5,000 non-fatal reoccurrence of heart attacks and strokes, Chen said.

``Moreover, continued treatment with clopidogrel after hospital discharge could lead to further net gains, although the benefits and hazards of more long-term therapy are still under investigation,'' Chen said in the study.

Novartis AG's beta-blocker Lopressor can cut the risk of repeat heart attacks and ventricular fibrillation by as much as 20 percent in heart attack patients, Chen also found. Still, Lopressor raised the risk of cardiac shock by 30 percent, so doctors should wait until a patient's condition has stabilized before starting with beta-blockers, drugs designed to help ease the workload of the heart, Chen said.

To contact the reporter on this story: Chantal Britt in Stockholm at cbritt@bloomberg.net.

Last Updated: November 3, 2005 19:05 EST