Inflammation of the Arteries and Heart Disease:
New Study Supports Link

A new study from Brigham and Women's Hospital supports the theory that heart disease may be related to inflammation of the arteries, according to a new study published in the New England Journal of Medicine.

The study used data from the Physicians' Health Study, an ongoing research project. The researchers, led by Dr. Paul Ridker, reviewed the case files of 543 male physicians who, over an eight year period, had suffered a heart attack, stroke or venous thrombosis, vs. 543 male physicians who had no evidence of vascular disease. Dr. Ridker and his colleagues found that those individuals who had initially exhibited a high level of C-reactive protein, an inflammation marker, were three times as likely to suffer a heart attack, and twice as likely to suffer a stroke as those patients with lower levels of the protein. Since no link was found between levels of C-reactive protein in the blood and the risk of developing blood clots in the veins, researchers maintain that the study's findings may be limited to the process of circulation in the arteries.

The level of C-reactive protein in the body can be measured by a simple blood test. The average initial level of C-reactive protein among those who later suffered a heart attack was 1.51 mg per liter; among stroke victims it was 1.39 mg per liter. The patients who had no vascular disease during the eight-year period had an average initial level of 1.13 mg of C-reactive protein/liter of blood. These risks were found to be independent of such "traditional" heart risk factors as high blood pressure, cholesterol, smoking and obesity.

The study also showed the important role that aspirin plays in potentially decreasing one's risk of heart attack and stroke. Among those individuals who initially tested in the highest quartile of C-reactive protein, but who took aspirin over the eight-year period, there was a reduction in heart attack risk of 55.7 %. The individuals who measured in the lowest quartile of C-reactive protein had only a small, non-significant reduction in risk (13.9%) from taking aspirin.

Traditionally, it was thought that aspirin played a role in reducing heart disease risk because of its anti-clotting properties. The Brigham and Women's researchers hypothesize that aspirin may be effective in reducing heart attack risk partly due to its anti-inflammatory properties, as well.

If inflammation is indeed a significant factor in the development of heart disease, then it may become central to the study of reducing heart attack risk. The senior study's author and Harvard professor of medicine, Dr. Charles H. Hennekens, emphasized that the effect of C-reactive protein in women needs to be examined, since no such data exist on women.

Blood levels of C-reactive protein were associated with the risk of future heart attacks and stroke among those patients in Dr. Ridker's study. If the research team's results can be replicated, it could strengthen the argument that inflammation plays a major role in heart disease, and that anti-inflammatory agents (such as aspirin) may have an even more important clinical benefit in preventing cardiovascular disease than previously known.

SOURCES: The New England Journal of Medicine (1997;336:973-979,1014-1015); Reuters, April 2, 1997