40 percent of Americans at moderate risk for heart disease

"About 40 percent of the American public is considered to be at moderate risk for heart disease," says Iftikhar Kullo, M.D., of Mayo Clinic, the lead author of the study.

"Nearly half the heart attacks come without warning, which means we need to do a better job of screening people. This test has that potential."

The test, aortic pulse wave velocity (aPWV), measures how fast the pulse wave travels down the aorta, the major artery arising from the heart. It is a potential screening tool because it is quick (takes 10-15 minutes), painless, noninvasive and likely to be less expensive compared with other cardiac screening tests, Dr. Kullo says. For the test, the patient lies on a bed and a pencil-like device (tonometer) is placed on the skin over the carotid artery (in the neck) and then the femoral artery (in the upper thigh). The tonometer measures the pressure wave inside the artery, and the information is fed into a computer for calculation of aPWV. A slower pulse wave means the artery is more elastic and healthier; a faster wave means the artery is stiffer and less healthy, he says.

The research found that study participants with stiffer arteries also had a greater presence and amount of calcium in the coronary arteries, an indicator of coronary atherosclerosis (plaque buildup). Previous research showed aPWV predicts cardiovascular disease in older adults, but the association of aPWV and the amount of coronary artery calcium (CAC) in the general population has been unknown, Dr. Kullo says.

The association between artery stiffness and CAC strengthens the case for using aPWV as a screening tool, such as in adults with moderate risk, those with a family history of heart disease, patients with high blood pressure, and those with kidney disease, Dr. Kullo says.

Researchers tested 401 participants (213 men and 188 women) between the ages of 32 and 84 -- none with a history of heart attack or stroke -- for the community-based research between 2002 and 2004. The median age was 60. This research also discovered a significant interaction between aPWV and smoking history; the association between aPWV and the presence and quantity of CAC was stronger in smokers than in nonsmokers, he says.