Jan. 11, 1999 WINSTON-SALEM, N.C. -- An ultrasound test of the arteries in the neck may help doctors pick out which patients need aggressive treatment to prevent heart attacks or strokes, according to new findings published in the Jan. 7 issue of the New England Journal of Medicine.
Researchers found that the increasing thickness of the walls of the common carotid and internal carotid arteries of the neck -- a direct measure of atherosclerosis (hardening of the arteries) -- was associated with increased rate of heart attack and stroke.
Gregory L. Burke, M.D., principal investigator at the Wake Forest University Baptist Medical Center for the Cardiovascular Health Study (CHS), said that the finding held true even when the researchers adjusted for all of the traditional risk factors for heart attack and stroke, such as smoking, high cholesterol and high blood pressure.
"Elevation of heart disease risk factors is more common in the elderly," Burke explained. "It may be difficult for clinicians to identify older patients with cardiovascular disease who don't have symptoms solely on the basis of classic risk factors."
The ultrasound measurements of the carotids, which is non-invasive, appears to provide additional information needed to "help identify asymptomatic persons who would benefit from aggressive prevention measures," he said.
Such aggressive measures might include lowering high blood pressure or high cholesterol levels further than in other patients, more strict control of diabetes, and perhaps medical or surgical intervention.
Beginning in 1989, the Cardiovascular Health Study enrolled 5,201 men and women over the age of 65 in Forsyth County (Winston-Salem), N.C., Washington County (Hagerstown), Md., Allegheny County (Pittsburgh) Pa., and Sacramento County, Calif. All those who have survived are now at least 72, with some as old as 100.
The new study included 4,476 of the CHS participants. The researchers divided the participants into fifths, based on the ultrasound measurement of the thickness of the walls of both the internal carotid and the common carotid arteries. The participants with the thinnest walls had 40 strokes or heart attacks over the course of the study, compared to 184 in those with the thickest walls, more than four times as much.
The measurement of the carotids is a direct indicator of the risk of strokes, since the blood supply for the brain courses primarily through those arteries. But since atherosclerotic buildup in the carotid arteries generally occurs in other arteries as well, the measurement of the carotids is an indirect indication of clogging of the coronary arteries supplying the heart.
The results suggest that "artery wall thickness is by itself as powerful a predictor of cardiovascular events as the traditional risk factors," said Burke
CHS is an observational study. The health of the participants is monitored regularly, and physical condition, lifestyle, diet and other parameters are recorded, but diagnosis and treatment is left in the hands of personal physicians. It is the largest National Heart, Lung and Blood Institute project to study cardiovascular disease in an elderly population.
Besides ultrasound of the carotid arteries of the neck, CHS uses other non-invasive, objective measures of both subclinical and clinical chronic diseases -- such as echocardiograms, electrocardiograms, spirometry to measure lung function, fasting glucose levels to look for diabetes, and objective measures of loss of memory and brain function.
The goal of the study is to learn as much as possible about the lifestyles and the physical condition of the participants at the outset to see how these factors affect the evolution of heart attacks and strokes.
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