Missing link between inflammatory markers in the bloodstream and the increased risk of heart attack

The study of 386 Olmsted County, Minn., residents used transesophageal echocardiography (TEE) to obtain high-quality images of the lining of the aorta, the main artery through which the heart pumps blood to the body.

TEE images are clearer than traditional echocardiograms because they come from an ultrasound probe inserted down the throat. This enables imaging of the heart and major blood vessels without interference from the ribs and chest wall.

The researchers found partial blockages, called atherosclerotic plaques, in the aortas of 69 percent of the study subjects, whose median age was 66. The level of high-sensitivity C-reactive protein (hs-CRP), a marker in the bloodstream that indicates inflammation, was the single factor most closely associated with the presence of plaques and their severity.

"This study is important because for the first time it gives us data on cholesterol, hs-CRP and other risk factors from people randomly selected from the community, and lets us correlate those results with the presence or absence of plaques," says Bijoy Khandheria, M.D., the Mayo Clinic cardiologist who led the study. "We have known for some time that hs-CRP levels are elevated among patients with chest pain or other heart-related symptoms. This new study tells us high CRP is a sign that plaques likely are being formed in the arteries, even if the person feels healthy. Our findings provide a missing link between inflammatory markers in the bloodstream and the increased risk of a cardiovascular event such as a heart attack."

Dr. Khandheria says the findings should cause doctors to take a closer look at patients who have elevated hs-CRP readings, and that doctors and patients should work together to reduce other risk factors. "Among our study volunteers with no heart disease symptoms who were found through TEE to have aortic plaques, a doubling of the hs-CRP nearly doubled the chances that the plaque would be a thicker, more dangerous one," he explains. "For people who have an elevated hs-CRP, we believe it's just a matter of time before they have a plaque buildup unless they take action. They need to be treated aggressively with aspirin and a statin to reduce inflammation and lower their cholesterol, and work to bring their weight and blood pressure down to recommended levels."

Authors of the paper, "C-Reactive Protein and Atherosclerosis of the Aorta," include Dr. Khandheria; Yoram Agmon, M.D.; Irene Meissner, M.D.; Tanya Petterson; W. Michael O'Fallon, Ph.D.; David Wiebers, M.D.; Teresa Christianson; Joseph McConnell, Ph.D.; Jack Whisnant, M.D.; James Seward, M.D. and A. Jamil Tajik, M.D.