Electron-beam tomography coronary calcium scores are superior to Framingham risk variables for predicting the measured proximal stenosis burden

Previous studies of electron-beam tomography (EBT) have correlated coronary calcium scores with simplistic visual estimates of disease severity. In a clinical trial designed to evaluate 2 treatment strategies in coronary arte ry disease (CAD) patients with low levels of high-density lipoprotein chole sterol, we used quantitative coronary angiography to measure composite prox imal stenosis burden from the baseline coronary angiogram and assessed the traditional Framingham risk variables in 146 patients. Stenosis burden is t he sum, per patient, of percent stenosis for the worst lesion found in each of 9 standard proximal coronary segments. EBT estimates of coronary calciu m (Agatston score, calcium volume score) were obtained for 115 of these pat ients. Stenosis burden was correlated with the calcium scares and risk vari ables. The best traditional correlates of stenosis burden were smoking stat us (r = 0.31, p = 0.001), prior myocardial infarction (r = 0.24, p = 0.005) , body mass index (r = 0.23, p = 0.005), pack-years smoking (r = 0.20, p = 0.05), and age (r = 0.17, p = 0.04). With adjustment for age, all these cor relations improved (eg, body mass index x age [r = 0.28, p = 0.001]). In ad dition, total cholesterol x age (r = 0.22, p = 0.008), fibrinogen x age (r = 0.19, p = 0.03), and systolic blood pressure x age (r = 0.18, p = 0.03) b ecame significant correlates. Spearman correlations of the calcium scores w ith stenosis burden were considerably greater (Agatston: r = 0.62, p <0.000 1; calcium volume: r = 0.63, p <0.0001). In multivariate regression analysi s, calcium score, body mass index, and history of myocardial infarction wer e independent correlates of stenosis burden (R-2 = 0.45). At a given point in time, the EBT coronary calcium scores are greatly superior to the Framin gham risk factors in predicting the measured proximal stenosis burden. Agat ston and calcium volume scores are comparably predictive of stenosis burden . (C) 2001 by Excerpts Medico, Inc.