All High-Risk Patients Should Not Be Screened With Computed Tomographic Angiography

Abstract

On the basis of the most recent American Heart Association/American College of Cardiology guidelines for assessment of cardiac risk,1 high-risk patients are defined as those with a 10-year coronary heart disease risk of >20% based on Framingham risk criteria or the presence of diabetes mellitus. The major independent risk factors for coronary heart disease comprising the Framingham Risk Score are cigarette smoking, hypertension, elevated total cholesterol and low-density lipoprotein cholesterol, low serum high-density lipoprotein cholesterol, diabetes mellitus, advanced age, and male gender.1 Derived from National Health and Nutrition Examination Survey statistics from 1999 to 2000,2 the prevalence of risk factors in patients aged 20 to 74 years is 17% for total cholesterol ≥240 mg/dL, 14.9% for hypertension, 26.4% for smoking, and 8% for diabetes (including undiagnosed). Data from the 2003 Behavioral Risk Factor Surveillance System survey of 103 191 adults aged >18 years3 show that >37% of the population surveyed had ≥2 risk factors for coronary heart disease and thus are considered to be at high risk. These figures together suggest that the number of high-risk patients who are potential candidates for screening programs is quite high. Response by Gottlieb p 1339 Multiple studies over the last 2 decades have confirmed the prognostic utility of coronary artery calcium (CAC) measurements primarily with electron-beam computed tomography (EBCT) and more recently with multidetector CT (MDCT) technology (Figures 1 and 2⇓). The 2 techniques are fairly equivalent as long as the latter is performed with at least a 4-detector scanner.4,5 The reproducibility of MDCT, however, may not be as good as EBCT at lower calcium scores.4 Figure 1. Noncontrast ECG-gated CT for CAC scoring in a single axial plane demonstrating dense calcification of the left anterior descending artery. Figure 2. Noncontrast ECG-gated CT for CAC scoring …