TUESDAY, Jan. 25, 2005 (HealthDayNews) -- Giving a special version of the blood thinner heparin in the hours after a heart attack can reduce the death rate and the incidence of a later heart attack, new Canadian research shows.
The study of more than 15,500 patients treated at hospitals in India and China found the 30-day death rate for heart attack patients given the drug reviparin was 13 percent lower than for patients who did not get the drug.
The incidence of second heart attacks was 23 percent lower in the patients who got reviparin, the study found. Equally significant was the finding that the incidence of stroke was not increased by use of the drug.
The research, carried out by scientists at McMaster University in Hamilton, is published in the Jan. 26 issue of the Journal of the American Medical Association.
Heparin is a clot-preventing drug made up of long chains of saccharides, or sugars. Reviparin is formally described as a low-molecular-weight heparin because it is made by chopping those chains into tiny units.
Smaller studies have shown that other low-molecular weight heparins appear to reduce the death rate for heart attack patients, but those trials were too small to be considered definitive.
"They [the Canadian researchers] succeeded in showing that it is effective," said Dr. Nieca Goldberg, chief of women's cardiac care at Lenox Hill Hospital in New York City, and a spokeswoman for the American Heart Association.
Reviparin is one of several low-molecular-weight heparins that have become available in the past few years. "We have seen several studies that show the benefit of low-molecular-weight heparin over the unfractionated form," Goldberg said. "This study shows it in the setting of an acute heart attack."
One advantage of the low-molecular-weight heparin is that it's less likely to induce uncontrolled bleeding that can lead to a stroke. Another is that it can be given by injection, rather than requiring infusion into a vein, a process that requires continuous monitoring, Goldberg said.
The benefits of low-molecular-weight heparin already are reflected in guidelines for treatment of some cardiovascular disorders, Goldberg noted. Still, the new study was needed to provide definite proof of the drug's value in treatment of a heart attack.
The need for such proof was demonstrated by another report in the same issue of the journal that evaluated the effect of another treatment, infusion of a high-glucose-insulin-potassium solution that has been regarded as a possible benefit for heart attack patients. The study found the solution did not reduce the death rate or incidence of cardiac arrest.
"On a theoretical basis, the infusion was supposed to be of benefit," Goldberg said. "In practice, it was not. This shows the importance of trials in actual clinical practice."
A primer on heparin and its medical uses is provided by the National Library of Medicine.