Measuring Risk - Simple, noninvasive test may help show heart disease risk in adults with no symptoms

A Mayo Clinic research team used a simple, noninvasive tool (called an arterial tonometer) to discover an association between stiffness in arteries and the presence and amount of calcium they contain. This finding may lead to more accurate and more widely available assessment of heart disease risk in adults with no symptoms.

Calcium buildup is one of the causes of coronary artery disease, the most common type of heart disease, affecting about 13 million Americans. Each year, more than 500,000 Americans die of complications of coronary artery disease. The problem is that many people who have this form of heart disease aren't aware they have it. Coronary artery disease develops slowly and silently over decades. It can go virtually unnoticed until it produces a heart attack.

"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 researcher in 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, called aortic pulse wave velocity (aPWV), measures how fast a pulse wave travels down the aorta, the major artery arising from the heart. It has potential as a screening tool because it is quick (it takes only 10 to 15 minutes), painless and noninvasive. It's also likely to be less expensive compared with other cardiac screening tests, says Dr. Kullo.

During the test, the patient lies on a bed and a pencil-like device called a tonometer is placed on the skin over the carotid artery (in the neck) and on the skin over the femoral artery (in the upper thigh). The tonometer measures the pressure wave inside the artery. The information it gathers is fed into a computer for calculation of aortic pulse wave velocity. A slower pulse wave means the artery is more elastic and healthier. A faster wave means the artery is stiffer and less healthy.

The researchers found that study participants with stiffer arteries had a greater amount of calcium in the coronary arteries, an indicator of coronary atherosclerosis (plaque buildup). Previous research had shown that aortic pulse wave velocity tests predicted cardiovascular disease in older adults. But the ability of the test to determine the amount of coronary artery calcium in the general population has been unknown, says Dr. Kullo.

The research findings strengthen the case for using aortic pulse wave velocity as a screening tool, says Dr. Kullo. The screening would be useful for adults with moderate risk, those with a family history of heart disease, patients with high blood pressure, and those with kidney disease.

Mayo Clinic and the University of Michigan collaborated on this research. Co-investigators were Patrick Sheedy, M.D., and Stephen Turner, M.D., of Mayo Clinic; and Lawrence Bielak, D.D.S., and Patricia Peyser, Ph.D., of the University of Michigan, Ann Arbor.