A cheap and painless set of tests developed in leading medical centers around the country promises to predict heart disease and stroke, and pinpoint the patients who really need aggressive therapy, far more accurately than do the traditional risk factors.
The new method includes a simple measurement of the difference in blood pressure between arms and ankles, and a noninvasive acoustic test that measures narrowing of the carotid arteries that carry blood to the brain.
Many patients with high cholesterol levels do not in fact develop heart disease. Conversely, there are also many patients who develop silent heart disease without having any of the known risk factors like high cholesterol, smoking and diabetes.
Dr. Lewis Kuller, an epidemiologist at the University of Pittsburgh who helped develop the new method, predicted that the technique would prove most useful for people over 60, especially those with high cholesterol, and for people of any age whose doctors think they may need drugs to help lower blood cholesterol or triglycerides, another fatty component of the blood. He also said the screening technique could be useful for people with moderately elevated systolic blood pressure (measured by the larger of the two blood pressure numbers) and for children and young adults with a strong family history of cardiovascular disease who might not otherwise be treated aggressively enough.
Without so much as a needle prick, the method indirectly measures the extent of hidden atherosclerosis, or clogging of the arteries, in people who have no outward symptoms of cardiovascular disease, such as chest pains. In a soon-to-be-published study of 5,200 older adults from four communities across the country, the researchers showed that people with significant clogging of their arteries, as determined by the new method, were two to three times as likely to die within a few years as were those without evidence of hidden, or so-called subclinical, arterial disease.
The risk of developing fatal and nonfatal coronary heart disease within the next three years was doubled for men and two and a half times greater for women who had evidence of subclinical disease. Consideration of traditional risk factors did little to change these results, the researchers concluded.
Dr. Michael Criqui, a specialist in preventive cardiology at the University of California at San Diego, described the work as "an area of major importance." He said the tests "provide a measure of an individual's propensity for developing atherosclerosis, and that outweighs all other risk factors" in predicting who will suffer a heart attack or stroke.
The tests involve no dyes or injections and no pain or risk of injury. They can be performed by trained technicians with instruments that cost a few hundred dollars and a computer to calculate the results. Two of the tests involve the use of high-frequency sound waves to assess potential blockages in the arteries that feed the brain. One of the most revealing tests, which measures the difference in blood pressure in the arms and the legs, could be put into widespread use almost immediately, Dr. Kuller said.
The study involved 2,239 men and 2,962 women aged 65 and older in Forsyth, N.C.; Sacramento County, Calif.; Washington County, Md., and Pittsburgh. Participants were followed for an average of two and a half years, some as long as three years. The findings, which will soon be published in the journal Circulation, showed that men with subclinical disease face a higher risk of developing or dying of cardiovascular disease than do women with hidden atherosclerosis.