New Test Predicts Sudden Death Risk
April 15, 2002 -- A simple blood test may be able to predict who is a risk of sudden death due to heart disease. A new study shows the test can reveal deadly, artery-clogging plaques in people at risk for sudden death -- even when they have no other symptoms of heart disease.
The study is published in today's issue of Circulation: Journal of the American Heart Association.
Researchers examined the hearts and blood samples of 302 people who'd died suddenly and found those who suffered sudden cardiac death had higher levels of a substance called C-reactive protein (CRP).
"There are people walking around with high CRP levels who have no idea they are at risk because all the other signs [that they may have severe heart disease] appear normal," says study author Renu Virmani, MD, a researcher with the U.S. Armed Forces Institute of Pathology in Washington, in a news release.
CRP is released when blood vessels are inflamed, as they are in people who have started to develop hardening of the arteries, or atherosclerosis. Previous studies have already shown that elevated blood levels of CRP indicate damage to the walls of the arteries and can predict heart attacks.
But the findings of this study show that the levels of CRP in the blood are even more telling than once thought. They can indicate which atherosclerotic plaques in the blood vessel are likely to rupture -- triggering the chain of events that cause sudden death. Determining which blood vessel plaques are most likely to rupture has been the focus of intense research, as doctors hope to identify people with these plaques and offer treatment before they have a heart attack or sudden death.
"If circulating CRP levels are elevated, there are more vulnerable plaques. It's that simple," says Virmani. "In the future, all patients should have their CRP levels checked. That way we can intervene with lifestyle counseling and drugs like statins and aspirin."
CRP is released into the bloodstream when blood vessels leading to the heart become damaged. The level of CRP in the blood can increase by 1,000 times when the body responds to a serious infection, trauma, burns, or other condition that causes inflammation.
In the study, nearly 53% of patients who had higher-than-average CRP levels had ruptured plaque, compared with only 20% of those who had died from other causes.
The study authors say the only other predictor of sudden cardiac death was smoking. About 70-80% of people with eroded plaques were smokers compared with 40% of people with stable plaques.-->