Detection of silent coronary artery disease by computed tomographic scan: coronary artery calcium versus noninvasive coronary angiography

OBJECTIVESMultislice computerized tomographic scan can identify coronary artery disease (CAD) with quantification of coronary artery calcium (CAC) and computed tomographic coronary angiography (CTA). The utility of CAC in comparison with CTA in asymptomatic patients has not been assessed. METHODSPatients with risk factors for CAD, who were referred for screening, were studied using CAC and CTA, using a Phillips Mx8000 IDT 16 multislice computed tomographic scanner. RESULTSThree hundred and forty-seven patients with a mean age of 55 years, 89.9% male, were included. CAC showed calcium deposits in 171 patients (49.3%) whereas CTA found lesions in 157 patients (45%). CAC correctly identified 309 patients with respect to CTA (presence of any disease) implying a test accuracy of 89%, sensitivity of 85%, specificity of 86%, and negative predictive value of 93%. Obstructive lesions were shown by 7.7% of the patients (stenosis >50%), 22% of the patients with CAC greater than 400, and 2.8% of the patients with CAC of 0. To undergo a CTA scan after CAC permits to re-classify 11% of the patients on the basis of CTA. CONCLUSIONCAC, in detecting silent CAD, seems to be a good alternative to CTA, in these asymptomatic patients, but CAC is inappropriate to predict the presence or absence of a coronary artery obstruction.