Coronary Artery Calcium Testing in Symptomatic Patients: An Issue of Diagnostic Efficiency.

The detection and quantification of coronary artery calcification (CAC) significantly improves cardiovascular risk prediction in asymptomatic patients. Many have advocated for expanded CAC testing in symptomatic patients based on data demonstrating that the absence of quantifiable CAC in patients with possible angina makes obstructive coronary artery disease (CAD) and subsequent adverse events highly unlikely. However, the widespread use of CAC testing in symptomatic patients may be limited by the high background prevalence of CAC and its low specificity for obstructive CAD, necessitating additional testing ('test layering') in a large percentage of eligible patients. Further, adequately powered prospective studies validating the comparative effectiveness of a 'CAC first' approach with regards to cost, safety, accuracy and clinical outcomes are lacking. Due to marked reductions in patient radiation exposure and higher comparative accuracy and prognostic value make coronary computed tomographic angiography the preferred CT-based test for appropriately selected symptomatic patients.