Patients with heart failure who have had a heart attack but not had artery-clearing angioplasty treatment are less likely to die early if they take the anti-clotting drug Plavix, study data showed on Monday.

The study by Danish scientists published in the Journal of the American College of Cardiology was the first to look at the effect of Plavix, known generically as clopidogrel, on death rates in specific high-risk patients with heart failure and heart attack.

Heart failure is a type of heart disease in which the heart is unable to pump enough blood around the body. Angioplasty is a non-surgical procedure to clear blocked arteries.

Because the value of using clopidogrel for heart failure patients had been long debated, the positive impact seen in the study was “of unquestionable practical importance,” researcher Victor Serebruany with the HeartDrug Research Laboratories at John Hopkins University in the United States said in a commentary on the findings.

The findings should bolster Plavix - the world’s second biggest-selling drug - which got a knock back on March 12 when U.S. regulators said it should carry a new warning on its label about patients who have a poor response to it.

Comparing groups of specific high-risk patients, researchers found that after 18 months, 32.2 percent died in the group that was not treated with Plavix versus 28.1 percent in the group that did receive it.

The results suggest that better awareness of Plavix’s benefits in such high-risk patients could have “considerable clinical impact,” the researchers wrote.

The drug is recommended to be given with aspirin to all patients who suffer heart attack, except those with an increased risk of bleeding, the researchers said.

“Despite these guidelines, however, no analyses have been done specifically on acute heart attack patients with heart failure,” they wrote, leaving doctors uncertain about how to best treat such patients.

The researchers used data from the Danish National Patient Register to create four patient groups from 31,251 patients hospitalized between 2000 and 2005.

They looked at two groups with heart failure - one receiving Plavix and one not, and two without heart failure - one receiving Plavix and one not.

They assessed the heart failure groups after 1.5 years and the non-heart failure groups after 2.05 years.

In patients without heart failure, Plavix had no effect on death rates, which were just over 9 percent in both groups, but its effect in the high-risk groups was significant.

SOURCE: Journal of the American College of Cardiology, March 30, 2010.