Post-mortem study finds that sudden death is associated with higher C-reactive protein levels in blood and coronary plaques


In a post-mortem study, people who had sudden cardiac death had higher levels of C-reactive protein in blood and in coronary plaques than people who died from non-cardiac causes, according to an article in the April 16th rapid access issue of Circulation.

"Our research provides the first indication that C-reactive protein is a risk factor for atherosclerotic vascular disease and sudden death," says lead investigator Renu Virmani, M.D.

In the American study, researchers autopsied 302 men and women lacking any inflammatory conditions other than atherosclerosis. These included 73 bodies with arterial blockages caused by plaque rupture or erosion, 71 bodies with stable arterial plaque, and 158 controls - the last group made up of people who died from non-cardiac sudden death and without any condition associated with elevated C-reactive protein level.

During the autopsy, researchers determined C-reactive protein levels from post-mortem blood samples and used a special staining technique to look at C-reactive protein in the plaque itself. They found that people who had sudden cardiac death had higher levels of C-reactive protein in their blood and their coronary plaque than those who died from non-cardiac causes.

Scientists have known for some time that elevated blood levels of C-reactive protein indicate damage to arterial walls. However, until now it has not been known that blood levels also correlate to levels within atherosclerotic plaque and plaque vulnerability to rupture, says Virmani.

"This is the first time it has been linked to sudden death from cardiovascular disease," she says. "If circulating C-reactive protein levels are elevated, there are more vulnerable plaques. It is that simple. It is very important to identify vulnerable plaques in order to begin treatment."

C-reactive protein can increase 1,000-fold in the bloodstream in response to acute infection, trauma, burns, and other inflammatory conditions. It is also released into the bloodstream when coronary arteries are constricted or damaged.

Along with C-reactive protein levels in plaque and in blood serum, the overall plaque burden on the heart, total cholesterol, diabetes, smoking history, and body mass index were determined for each subject. The number of thin-cap plaques, also called atheroma, per heart was also determined. Plaques with thin caps are the least stable and most likely to rupture unexpectedly. C-reactive protein levels were compared and subjects were stratified into highest and lowest quintiles.

"It's exciting to think we may be able to detect the culprit lesion that might kill a patient," explains Virmani. "There are people walking around with high C-reactive protein levels who have no idea they are at risk because all the other signs appear normal. C-reactive protein is the only abnormality that gives rise to heightened risk of sudden death once factors such as pneumonia and other conditions that raise C-reactive protein levels are factored out."

The researchers found the median C-reactive protein level was 3.2 micrograms per milliliter (ug/mL) in cases with acute plaque rupture, 2.9 ug/mL in cases with plaque erosion, 2.5 ug/mL in cases with stable plaque, and 1.4 ug/mL in the control group.

In the study, 52.8 percent of people whose plaque had ruptured had serum levels above 3 ug/mL compared with only 20 percent of controls. About 39 percent of people with eroded plaques and 35 percent of people with stable plaque had levels above 3 ug/mL.

Previous studies have shown that baseline plasma levels of circulating C-reactive protein can predict risk of future stroke and myocardial infarction. In unstable angina, elevated levels are associated with poorer disease prognosis. This study shows C-reactive protein is also significantly elevated in patients with coronary artery disease, both with and without acute coronary thrombosis.

The only other predictor of sudden cardiac death determined in the study was cigarette smoking. About 70 to 80 percent of people with eroded plaques were smokers compared with 40 percent of people with stable plaque.

"In the future, all patients should have their C-reactive protein levels checked. That way we can intervene with lifestyle counseling and drugs like statins and aspirin," Virmani says.


DOLについて - 利用規約 -  会員規約 -  著作権 - サイトポリシー - 免責条項 - お問い合わせ
Copyright 2000-2025 by HESCO International, Ltd.