ATLANTA -- A blood-thinning drug from The Medicines Company ( MDCO) is showing promise for treating serious heart problems, according to the latest data. The drug, Angiomax, is already on the market for more general use. But approval for the specific treatment of acute coronary syndromes like heart attacks and angina would prove a boon for its maker. Angiomax, known generically as bivalirudin, proved safer and just as effective at treating patients with acute coronary syndromes as heparin, a commonly used blood thinner that¿s been on the market for more than 40 years, according to trial data presented here Sunday at the American College of Cardiology. The trial, dubbed Acuity and funded by The Medicines Company, concluded that Angiomax could potentially replace heparin and its close relatives. Heparin is effective at preventing blood clotting, but determining the right dose can be tricky and when doctors use too much, dangerous bleeding can result. In the Acuity trial, which tested 13,800 patients, major bleeding occurred in only 3% of those taking Angiomax, vs. 5.7% for heparin. "The Acuity results reinforce the message that replacing heparin with Angiomax improves outcomes, even in high-risk patients with acute coronary syndromes," said Clive Meanwell, chairman and CEO of The Medicines Company. "The Acuity outcome is simple and definitive -- Angiomax can become a major element in the platform of contemporary ACS treatment." Shares of The Medicines Company finished Friday up 68 cents, or 3.6%, at $19.46.