The test detects low levels of a protein that indicates systemic inflammation in the body. Scientists have found a link between such inflammation and the buildup of harmful plaque in blood vessels. A study of 28,000 women, published in the New England Journal of Medicine in 2002, showed it to be a predictor of heart attacks.
The CRP should be considered along with other markers for heart disease. Last year the American Heart Assn. and the Centers for Disease Control & Prevention recommended limited use of the test, saying it could be beneficial for people thought to have a midrange 10% to 20% chance of heart attack or cardiac death within the next 10 years, based on factors such as age, cholesterol levels, blood pressure, smoking, and the presence or absence of diabetes. In such cases, the CRP could help a physician who is undecided about the course of treatment. But according to Dr. Thomas Pearson, a preventive cardiologist and co-chairman of the group that came up with the AHA/CDC recommendation, the CRP is unnecessary for patients at highest risk (since they should be treated aggressively in any case) or at low risk (since CRP results would be unlikely to push such patients into a category requiring treatment). In such cases, says Dr. Pearson, a CRP would be just an added expense that could lead to overtreatment.LOW-COST PEACE OF MIND
On the other hand, Dr. Richard Stein, a cardiologist and associate chairman of the department of medicine at Beth Israel Medical Center in New York, says the test can be done at no charge if bundled with other common heart screens and can be performed using the same blood. Most cardiologists now routinely include the CRP in the battery of tests ordered for their patients, though internists and family doctors are less likely to do so, he says. "I think it would be helpful for any man over 40 or any woman over 45 who goes in for a risk assessment to have this test," says Dr. Stein.
Given the latitude in the new guidelines for when to use drugs to lower LDL, Dr. Stein says the CRP would help him decide what to recommend. A 55-year-old with an LDL level in the 100-to-130 range but a low CRP and no other heart disease risks might get by with diet and lifestyle changes, he says, while someone with the same LDL but a high CRP and other risk factors should probably take a statin drug. Even Dr. Pearson says the test's usefulness has increased because of the new cholesterol guidelines. By Carol Marie Cropper