A Logical Approach to Screening for Coronary Artery Disease

Although changes in lifestyle may increase the life expectancy of persons at high risk for coronary disease, there is no cost-effective screening test that can select these persons from the general population. Exercise testing has been considered, but epidemiologic studies have not proved that it effectively identifies persons at risk for myocardial infarction or cardiac death. Theoretically, exercise testing should have limited sensitivity in predicting events because abnormal responses occur only when sufficient atherosclerotic plaque has accumulated to impede coronary flow. Abnormal test responses cannot occur before plaque has reached such dimensions. A test that indicates the presence of any atherosclerotic plaque in the coronary lumen would be more useful than one that indicates compromise of blood flow. Data show that sensitive detection of coronary calcific deposits accurately predicts the presence of atherosclerotic plaque. Sensitive radiographic techniques such as digital subtraction fluoroscopy need to be developed as screening tests. Screening studies should be blinded and include only hard endpoints, and follow-up periods should be no less than 10 years so that the detected disease can develop to its symptomatic endpoint.