Some heart screenings may do more harm than good

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Updated: August 30, 2011 12:17AM

Screening people at low risk for heart disease with a test that detects blocked arteries appears to do more harm than good, new research suggests.

Patients found to have evidence of plaque buildup in their arteries after being screened with a test known as a coronary CT angiogram received more medication, follow-up tests and heart procedures than people who hadn’t been screened or those who had a normal test result.

Yet more treatment and tests didn’t significantly reduce the risk of cardiovascular incidents for these patients after 18 months, researchers reported online Monday in the journal Archives of Internal Medicine.

Low-risk patients are those who have risk factors for heart disease, but no symptoms. Early detection of heart disease in this population is a sought-after goal, since more than half of cardiovascular disease deaths occur in asymptomatic people.

Coronary CT angiogram, a special kind of X-ray that takes pictures of the heart, is a noninvasive way to identify atherosclerosis, or hardening of the coronary arteries caused by plaque buildup.

But the new study suggests that use of this test in patients without classic symptoms of heart disease can “trigger physician behavior which is not actually indicated based on guidelines or evidence,” said lead study author John W. McEvoy, of Johns Hopkins Ciccarone Center for Prevention of Heart Disease.

“In general, screening for atherosclerosis with coronary CT angiogram in a low- to intermediate-risk group does not appear to be useful and may be harmful,” because it can lead to even more testing and procedures with questionable benefit, McEvoy said.

Coronary CT angiogram also exposes patients to low-dose radiation, which has its own risks.

In the study, researchers compared outcomes for more than 1,000 South Koreans who received coronary CT angiograms as part of a health screening program to those of an equal number of participants in the same program who did not.

Patients who had a positive scan, meaning there was evidence of atherosclerosis, were more likely to be prescribed aspirin and cholesterol-lowering statins and be referred for additional heart tests than unscreened patients. They were also more likely to undergo procedures to restore normal blood flow to the heart.

Yet, after 18 months, there was no difference between the screened and unscreened groups in heart disease deaths, heart attacks or other cardiac events.