Relation of a Coronary Artery Calcium Score Higher Than 400 to Coronary Stenoses Detected Using Multidetector Computed Tomography and to Traditional Cardiovascular Risk Factors

Abstract

Coronary artery calcium (CAC) is an excellent surrogate for atherosclerosis. However, this calcium is nonspecific for obstructive heart disease. This study sought to determine (1) the frequency of significant computed tomographic (CT) angiographic stenoses as a function of CAC scores, and (2) whether high CAC scores were associated with these stenoses independent of traditional risk factors. Subjects (n = 664) underwent Agatston CAC scoring and multidetector CT angiography using current 64-slice technology. Significant stenoses were defined as >60% diameter compromise. Self-reported risk factors and frequency of stenoses were analyzed as a function of CAC scores. The prevalence of risk factors increased significantly as CAC scores increased. Significant univariate associations included age (p <0.001), male gender (p <0.001), hypertension (p <0.001), and hyperlipidemia (p <0.001). There was also a significant association between CAC scores and the frequency of significant CT angiographic stenoses (p <0.001 for trend). The frequency of CT angiographic stenoses increased as CAC scores increased, with 7.9%, 8.3%, 14.5%, and 27.2% prevalences of significant stenoses in those with CAC scores of 1 to 100, 101 to 400, 401 to 1,000, and >1,000, respectively. Conversely, no significant lesions were found in those with no CAC. Multivariable logistic regression analysis controlling for traditional risk factors showed odds ratios for CAC score of 401 to 1,000 and >1,000 for having significant stenoses of 3.1 (95% confidence interval 1.6 to 6.0) and 6.9 (95% confidence interval 3.5 to 13.5), respectively. In conclusion, a CAC score >400 was significantly associated with multidetector CT angiographic stenoses independently of traditional risk factors.