Rates of progression of coronary calcium by electron beam tomography

In this study, we sought to determine the rate of progression of atherosclerosis using coronary calcium scores derived from electron beam tomography (EBT). We studied a variety of disease states (hypertension, high cholesterol, tobacco use, diabetes mellitus) followed for 1 to 6.5 years. We evaluated 299 asymptomatic persons (227 men and 72 women) who underwent 2 consecutive EBT scans at least 12 months apart. The average change in the calcium score (Agatston method) for the entire group was 33.2 ± 9.2%/year. The treated group (receiving statins) demonstrated an average increase in calcium scores of 15 ± 8%/year compared with 39 ± 12%/year for untreated patients (p <0.001). Among the 60 patients on statin monotherapy, 37% had a decrease in the calcium score from baseline to follow-up scan. The relative increase in calcium scores did not vary significantly by gender or risk factors, with the exception of statin-treated hypercholesterolemic subjects. Scores of zero on the initial scan portend a low likelihood of significant calcific deposits on repeat scanning. Only 2 of 81 participants (2%) with scores of zero at baseline had scores >10 on repeat study. In this study, statin therapy induced a 61% reduction in the rate of coronary calcium progression. This study demonstrates that EBT may be a useful tool in assessing efficacy of different interventions to retard progression of atherosclerosis, noninvasively, over relatively short time periods.