Preventive surgery also has its risks.

• Position: Stroke

It is a medical Catch-22: carotid artery surgery can cause stroke, but so can asymptomatic carotid disease if left untreated. Researchers at the University of Texas Southwestern Medical Center, Dallas, have developed a clinical risk prediction rule using factors such as sex, race, and health history to assess the danger surgery poses.

"It may take a thief to catch a thief, but physicians certainly do not want to cause stroke while trying to prevent stroke, so being able to carefully weigh an individual's benefits against the risk of carotid surgery is critically important," emphasizes Ethan Halm, chief of the Division of General Internal Medicine.

Researchers drew on factors that increase the risk for postsurgical death or stroke for people with silent, or asymptomatic, carotid disease to predict which patients were at highest risk for complications. Those most at risk were female, nonwhite, and had certain neurologic and heart diseases.

The carotid arteries, which run on the sides of the neck, are main blood vessels that supply oxygen to the brain. They can become narrowed by fatty cholesterol deposits called plaque. If pieces of plaque break free, they can lodge in the brain, causing stroke. In carotid endarterectomy (CEA), one of the most common types of...