Aspirin Fights Heart Disease the Old Way
Reduces artery inflammation as well as clots, study shows
MONDAY, May 13, 2002 (HealthDayNews) -- Most people know aspirin reduces the risk of cardiovascular disease by preventing the formation of clots that can block arteries, but new research illuminates another dimension of its protective qualities: It reduces the inflammation that can damage those arteries.
"This is a reflection of the initial anti-inflammatory property of aspirin, the basis of its use in diseases like arthritis for over 100 years," says study author Dr. Patrick J.T. Vallance, a professor of clinical pharmacology at University College London, England. His group reports its findings in tomorrow's issue of Circulation.
"What is new is the idea that this known property of aspirin aligns closely with the understanding of its role in cardiovascular disease, because cardiovascular disease has an inflammatory component," Vallance says.
To prove that point, Vallance and his colleagues did a study with 17 volunteers who agreed to be injected with a typhoid vaccine that causes inflammation. Some of the volunteers got aspirin before the injection, some got it afterward, and others were given a placebo. The degree of inflammation was determined by measuring blood levels of interleukin-1 (IL-1), an inflammation-related molecule.
Blood levels of IL-1 in the people who got the placebo rose 30-fold in the three hours after the injection, and remained at those elevated levels for eight hours. There was no such rise in the people who got aspirin before the typhoid shot, although IL-1 levels did go up in those who took aspirin after the injection. Another test showed reduced blood flow in those who got the placebo, but increased blood flow in those who got aspirin.
"This might broaden our concept of how to use aspirin as a preventive measure," Vallance says. Specifically, he thinks it might be helpful for people who have major surgery.
"There is a big surge of inflammation-related deaths in the month following abdominal surgery," Vallance says. "The hypothesis is that if you take aspirin before surgery, it might have a protective effect."
A controlled study of surgery patients would be needed to test that hypothesis, Vallance says, and that is not his department: "We're hoping somebody else might pick up on that."
Benefit and risk would have to be balanced in such a study, Vallance says, because aspirin's blood-thinning effect might cause excess bleeding.
The new study "raises the intriguing possibility that the benefits of aspirin are not confined to its anti-clotting effects," says Dr. Charles H. Hennekens, a professor of medicine, epidemiology and public health at the University of Miami School of Public Health who has done similar research and is a spokesman for the Aspirin Foundation of America.
"In 1997, we published a paper in the New England Journal of Medicine about C-reactive protein," says Hennekens, who was then at Harvard. C-reactive protein is another inflammation-related molecule.
"What we showed in that study was that this inflammatory marker is a predictor of cardiovascular disease. We found that the protective effects of aspirin were greatest in patients with a higher level of C-reactive protein," he says.
A new study to tell whether aspirin before surgery can reduce problems might not be necessary, Hennekens says.
Data is available from trials in which people took either aspirin or a placebo to prevent heart disease. Some of those people later underwent surgery, and a review showed that "people who got aspirin had a lower risk of developing pulmonary embolisms or deep-vein thrombosis," both life-threatening conditions, Hennekens says.
A further review of the data could show whether pre-surgical aspirin does save lives, he says.