Coronary Artery Calcium Progression: An Important Clinical Measurement?

Baseline coronary artery calcification (CAC) accurately identifies coronary atherosclerosis and might improve prediction of future cardiac events. Serial assessment of CAC scores has been proposed for monitoring atherosclerosis progression and for assessing the effectiveness of medical therapies aimed at reducing cardiac risk. However, whether knowledge of progression of CAC scores over time further improves risk prediction is unclear. Several trials relating medical therapies to CAC progression have been performed without any formal guidelines on the definition of CAC progression and how it is best quantified. We conducted a comprehensive review of published reports on CAC progression. Increased CAC progression is associated with many known cardiac risk factors. We found that CAC progression correlates with worsening atherosclerosis and may facilitate prediction of future cardiac events. These findings support the notion that slowing CAC progression with therapeutic interventions might provide prognostic benefit. However, despite promising early data, such interventions (most notably with statin therapy) have not been shown to slow the progression of CAC in any randomized controlled trial to date, outside of post hoc subgroup analyses. Thus, routine quantification of CAC progression cannot currently be recommended in clinical practice. First, standards of how CAC progression should be defined and assessed need to be developed. In addition, there remains a need for further studies analyzing the effect of other cardiac therapies on CAC progression and cardiac outcomes.