Prevalence and severity of coronary artery disease and adverse events among symptomatic patients with coronary artery calcification scores of zero undergoing coronary computed tomography angiography: results from the CONFIRM (Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter) registry

OBJECTIVES The purpose of this study was to describe the prevalence and severity of coronary artery disease (CAD) in relation to prognosis in symptomatic patients without coronary artery calcification (CAC) undergoing coronary computed tomography angiography (CCTA). BACKGROUND The frequency and clinical relevance of CAD in patients without CAC are unclear. METHODS We identified 10037 symptomatic patients without CAD who underwent concomitant CCTA and CAC scoring. CAD was assessed as 0 had a sensitivity specificity and negative and positive predictive values for stenosis =50 of 89 59 96 and 29 respectively. During a median of 2.1 years there was no difference in mortality among patients with a CAC score of 0 irrespective of obstructive CAD. Among 8907 patients with follow up for the composite endpoint 3.9 with a CAC score of 0 and =50 stenosis experienced an event (hazard ratio: 5.7; 95 confidence interval: 2.5 to 13.1; p < 0.001) compared with 0.8 of patients with a CAC score of 0 and no obstructive CAD. Receiver operator characteristic curve analysis demonstrated that the CAC score did not add incremental prognostic information compared with CAD extent on CCTA for the composite endpoint (CCTA area under the curve = 0.825; CAC + CCTA area under the curve = 0.826; p = 0.84). CONCLUSIONS In symptomatic patients with a CAC score of 0 obstructive CAD is possible and is associated with increased cardiovascular events. CAC scoring did not add incremental prognostic information to CCTA.