SAN DIEGO, March 2 - A noninvasive, high-speed X-ray scan is more accurate than relying on traditional risk factors for determining an individual's risk for heart disease, according to a study presented today at the American Heart Association's 40th Annual Conference on Cardiovascular Disease Epidemiology and Prevention.
Conventional risk factors for heart disease include high cholesterol levels, high blood pressure, obesity, physical inactivity, diabetes and smoking. Researchers found that electron beam computed tomography (EBCT) was significantly better than standard risk factors for categorizing heart disease risk. However, when they combined EBCT with risk factors, such as elevated cholesterol, their ability to assess an individual's heart disease risk was better than EBCT alone, says lead author Ming Wei, M.D., a clinical epidemiologist at the Cooper Institute, a not-for-profit research center in Dallas, Texas.
"EBCT may add significant information to conventional risk factors for determining a patient's level of or risk for heart disease," says Wei. "This could help physicians provide early treatment to patients at risk for a heart attack and possibly even prevent heart disease from progressing in those patients."
Co-author Larry W. Gibbons, M.D., of the Cooper Clinic, a medical facility associated with the Cooper Institute, adds that the "evaluation is very quick and very easy. However, the big question is how well does it help us to identify those people at high risk for developing heart disease?"
The researchers were trying to determine whether EBCT scans, which typically cost $400 to $500, improved the assessment of heart disease risk beyond what a physician could learn from a patient's risk factors. They studied 1,133 men and women, with an average age of 54, who received both a risk factor assessment and an EBCT scan at the Cooper Clinic.
The researchers identified heart disease in 110 of the patients in the study. They based their final diagnosis on the results of an angiogram, as well as heart attacks.
Unlike conventional CT scans, EBCT scans can measure calcium deposits in heart arteries. Because EBCT obtains high-resolution images so quickly, the pictures are not blurred like they are with conventional CT. Because of this, EBCT can locate deposits in heart arteries that have calcified, showing how extensive that calcification is.
Research has shown that the more calcium an individual has in his or her heart arteries, the more likely they are to have heart disease. With EBCT, a physician can make some judgements about how much the calcium increases a person's risk of a heart attack, Gibbons says.
He adds that EBCT is not designed to take the place of angiography for providing a definite diagnosis of heart disease because it cannot evaluate blood flow in the arteries, or show the percentage of narrowing in a heart artery. However, the technique has attracted considerable attention as a way to assess a person's risk for heart disease. It has also stirred controversy surrounding its usefulness, researchers say.
"EBCT is a useful tool for increasing our ability to identify people at risk for heart disease," Gibbons says. "If someone has risk factors such as a family history or diabetes, for example, this tool might well determine the presence or extent of heart disease." Gibbons adds that EBCT can also help physicians and patients make treatment decisions.
"If people have a history of moderately elevated cholesterol, an EBCT scan is a great way to help them decide, along with their physician, whether to begin taking cholesterol-lowering medication," Gibbons says. "If they have no calcium in their arteries, then chances are they don't need to be on medication. But if they are accumulating calcium in their heart arteries, then the physician would probably decide on aggressive medication for that patient." Co-authors are Tedd Mitchell, M.D. and Steven N. Blair, P.E.D.
Media advisory: Dr. Wei can be reached at (972) 341-3296. Dr. Gibbons can be reached at (972) 239-7223. (Please do not publish telephone numbers.)