Two studies presented Wednesday at the American College of Cardiology's annual scientific sessions in Orlando, Fla. have found that the clot-preventing drug Plavix when added to the treatment of people with severe heart attacks helps reopen their clogged arteries and saves lives.
Plavix reduces clotting by preventing the blood cells called platelets from clumping together and is now used to prevent artery blockage in people at high risk of heart attacks and those who undergo the artery-opening procedure called angioplasty.
A study by Dr. Marc S. Sabatine, an associate physician at Brigham and Women's Hospital in Boston, of almost 3,500 people treated in the first hours after a heart attack showed that those who got Plavix in addition to a clot-dissolving drug and aspirin - the current standard treatment - were 36 percent less likely to die or to have another heart attack.
"This treatment applies to patients coming in with the most severe form of heart attack, where the artery is completely blocked," Sabatine said. "There are about a million heart attacks in the US every year, and about a third of them are the severe kind, where the artery needs to be reopened immediately. "The study will be published in the March 24 issue of the New England Journal of Medicine.
The trial was not large enough to demonstrate that treatment improves long-term survival, a trial with tens of thousands of patients would be needed to do that, but the figures are good enough to justify its use, in preventing additional heart attacks, you can prevent deaths, said Dr. Richard A. Lange, chief of clinical cardiology at the Johns Hopkins School of Medicine and co-author of an accompanying editorial in the journal.
Sabatine said a second study done in China as a joint Chinese-British effort, fills that gap.It included nearly 46,000 heart attack patients treated at 1,250 hospitals. The usual practice in China is to give only aspirin to such patients, because clot-dissolving drugs are too expensive. Adding Plavix to aspirin reduced the death rate by 7 percent, said Dr. Zhengming Chen, of Oxford University in England, a study leader.
The large trial designed to answer the mortality question, shows a significant decline in mortality. This is the first new drug in a decade for the treatment of heart attacks.
The Chinese study is especially significant for less wealthy countries, Lange said. "Plavix is not so expensive," he said. "It's not as good as giving a clot-busting medication, but more effective than giving aspirin alone."
A European study, at Campus Biomedico University of Rome by Dr. Germano Di Sciascio, professor and chairman of cardiology has also shown the benefit of Plavix. Doubling the usual dose of the drug given before angioplasty reduced the incidence of heart attacks, the need for more artery-opening procedures, and deaths.
This trial included 255 people who underwent angioplasty. Only 4 percent of those given 600 milligrams of Plavix, double the standard dose, had a heart attack or other cardiac problem within 30 days, compared to 12 percent of those given the usual 300 milligrams, Di Sciascio said. Another report, found that St. John's wort, a medicinal herb with clot-preventing activity, appears to amplify the action of Plavix but could raise a patient's risk for bleeding.
A trial involving six people, selected because they had below-normal responses to Plavix, found that daily doses of St. John's wort given for three weeks doubled the clot-preventing activity of Plavix, researchers at the University of Michigan Cardiovascular Center reported.
They plan a larger study to confirm the finding, but advise patients to be honest with their doctors about any herbals they might be taking, since potentially harmful herbal-drug interactions can occur.