Calcified versus noncalcified atherosclerosis: Implications for evaluating cardiovascular risk

Although the quantification of coronary arterial calcification (CAC) correlates well with disease burden, calcified plaques only represent a portion of the total plaque burden. Contrast-enhanced multidetector CT angiography has emerged as a promising noninvasive tool to directly examine the coronary artery wall and accurately determine atherosclerotic plaque burden and composition. Published literature on plaque subtypes (noncalcified, mixed, and calcified) suggests that mixed plaque burden is more likely to be associated with high-risk groups, such as those with diabetes mellitus, inflammatory biomarkers, increasing stenotic coronary artery disease, myocardial perfusion defects, higher CAC scores and, more importantly, features of plaque instability such as thin-cap fibroatheroma. One small study suggested that mixed plaque burden can predict cardiovascular outcomes. Based on emerging data, determination of mixed plaque burden appears more promising, but the value of exclusively calcified and noncalcified plaque is less convincing.