Is artery screening cost-effective?

The carotid artery runs through the neck, branching to the face and brain. In people with antherosclerosis, fatty deposits may build up at the branch point -- the place where you feel your pulse. With time, the deposits may block the artery completely or a piece of plaque may break off and lodge in the brain. The result is a stroke, which kills brain cells by depriving them of oxygen and nutrients. The dying cells then wreak havoc on surrounding parts of the brain.

In 1995, a national trial revealed that surgery can reduce the risk of stroke in symptom-free men whose carotid arteries are narrowed by fatty deposits. This has led many physicians to examine apparently healthy patients who have risk factors for carotid artery disease. If a partial blockage is found, the artery is cleaned out.

The problem, explains Colin P. Derdeyn, assistant professor of radiology, Washington University School of Medicine in St. Louis, is that many of these men soon die from other causes such as heart disease. Moreover, the diagnostic and surgical procedures themselves carry a small risk of stroke. So, should doctors go looking for carotid artery stenosis, or should they act only if symptoms appear?

Derdeyn and William J. Powers, associate professor of neurology and radiology, have addressed this dilemma with a computer model to test whether ultrasound screening of asymptomatic men either once at age 60 or every year for the next 20 years would be beneficial. The men would have risk factors such as heart disease, evidence of peripheral vascular disease, or a bruit (a murmur heard through a stethoscope placed over the carotid artery). "Our model shows that, for men at high risk for carotid artery disease, a one-time screening...