Blood Test Could Save More From Heart Attacks
June 27, 2001 -- Popular drugs that can hammer down cholesterol levels may very well be a panacea for preventing heart attacks, too. But who should receive these drugs? Experts already know that the drugs, called statins, can prevent a second heart attack. Now more research shows that a simple test can help identify who else can benefit from them.
Statins were first shown to reduce the risk of a second heart attack in people with high cholesterol, and then they were shown to prevent a first heart attack in people with high cholesterol. A report in the June 28 issue of The New England Journal of Medicine nowshows that statins can prevent a first heart attack in people with normal cholesterol levels. They work by reducing levels of a protein called CRP.
An increase in CRP indicates inflammation. Inflammation in the arteries probably makes plaque -- the fatty substance that builds up on artery walls -- unstable and more likely to break apart, explains study author Paul Ridker, MD, PhD. When plaque breaks or fractures, a blood clot can form. That clot can then block blood flow to the heart and cause a heart attack.
Therefore, if CRP is higher than normal, "the risk for heart attack is higher than normal," Ridker tells WebMD. This is true "even if a person has normal cholesterol levels." High cholesterol also is a risk factor for heart attacks.
And statins are just as effective at lowering CRP -- and reducing the CRP-associated risk for heart attack -- as they are for lowering cholesterol, Ridker adds. That says a lot since statins are the primary treatment for high cholesterol.
What's more, doctors can use a simple blood test to measure CRP and determine who will benefit from statin therapy.
The test used by heart specialists is called a high-sensitivity CRP test and is now available in most major heart centers, says Kenny Jailal, MD, a professor of medicine at the University of Texas Southwestern Medical Center at Dallas. He cautions, however, that because CRP goes up in the presence of inflammation, a one-time finding of elevated CRP does not necessarily confirm an increased risk for heart attacks. So Jailal recommends at least two CRP measurements to confirm the true level.
Ridker evaluated more than 5,700 healthy volunteers with no history of heart disease and average cholesterol levels. He found that people with elevated CRP levels who took a statin called Mevacor lowered their CRP levels nearly 15%. As expected, Mevacor also reduced cholesterol in those who had elevated cholesterol, he says. "Lowering cholesterol reduced the risk for heart attack," Ridker says. And among people with elevated CRP and relatively low levels of cholesterol, "the drug also reduced the risk."