Study Compares Use of Anti-Clotting Drugs for Heart Patients

Researchers found little difference between two forms of heparin

TUESDAY, Nov. 22, 2005 (HealthDay News) -- Acute coronary syndromes include potentially fatal conditions involving a stoppage or reduction of blood to the heart, such as angina or heart attack.

Doctors have long debated how to treat these syndromes, and a new study finds that patients treated with two forms of anticoagulant -- low-molecular-weight heparin or unfractionated heparin -- have similar outcomes at one year, researchers report.

Both drugs have been used in the hospital to reduce the risk of blood clots during the first 24 hours after a heart attack, but which is best has not been known.

In this latest trial involving nearly 10,000 participants, high-risk patients were randomly assigned to receive low-molecular-weight heparin (enoxaparin) or unfractionated heparin. The study appears in the Nov. 23/30 issue of the Journal of the American Medical Association.

At 30 days post-treatment, enoxaparin was shown to be as effective as unfractionated heparin in reducing death or heart attack. Now, a team led by Dr. Kenneth W. Mahaffey, from Duke Clinical Research Institute in Durham, N.C., is reporting six-month and one-year data from the trial.

Among the 9,978 patients, 541 died at six months and 739 died by the one-year mark. Mahaffey's team found that 872 patients who received enoxaparin had a heart attack at six months compared with 884 who received unfractionated heparin. In addition, the number of patients who were rehospitalized at six months was similar in both groups.

"Despite aggressive revascularization strategies and high use of evidence-based therapies, patients with high-risk acute coronary syndrome features remain at risk for continued adverse cardiac morbidity and mortality," the researchers conclude.

The study was funded by Aventis Pharmaceuticals, a member of the Sanofi-Aventis Group, which markets enoxaparin (Lovenox).

One expert found the study results discouraging.

"Unfortunately, despite aggressive therapy of patients with acute coronary artery disease with stents, blood thinners, cholesterol medication and ACE inhibitors, there was a high rate of recurrent heart disease," said Dr. Nieca Goldberg, chief of Cardiac Rehabilitation and Prevention Center at Lenox Hill Hospital and an assistant clinical professor of medicine at New York University School of Medicine in New York City.

"Clearly the study showed that it didn't matter which type of heparin the patients received in the hospital," she added.

"Preventing the first heart attack is key -- all of us should have our heart disease risk factors checked so we can work on those to prevent going to the ER or hospital," Goldberg said. "Patients with heart disease should be regularly monitored and referred to exercise programs, and their medications should be reviewed at each doctor's visit."

Another expert doesn't think the study adds much to what was known before.

"These anticoagulant treatments are only given in the hospital for about 24 hours," notes Dr. Ethan J. Weiss, an assistant professor of medicine at the University of California, San Francisco. "So it would be unusual to find any difference after one year," he added.

"This study isn't going to change the way anyone practices," Weiss said. "I don't think we've learned anything about which drug to use in acute coronary syndrome from these data."

More information

The American Heart Association has more on acute coronary syndrome.

SOURCES: Ethan J. Weiss, M.D., assistant professor, medicine, University of California, San Francisco; Nieca Goldberg, M.D., chief, Cardiac Rehabilitation and Prevention Center, Lenox Hill Hospital, and assistant clinical professor, medicine, New York University School of Medicine, New York City; Nov. 23/30, 2005, Journal of the American Medical Association
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