Abstract 14026: Absence of Coronary Calcification in Patients at Low Risk for Future Cardiovascular Events Robustly Predicts Absence of Obstructive Coronary Artery Disease by Coronary CT Angiography
Objectives: There are conflicting results regarding the prevalence of presence of obstructive CAD as evaluated by coronary CT angiography (CCTA) in the absence of any coronary artery calcium (CAC). Most of the studies were limited by small sample size for patients with CAC=0. We evaluated whether the absence of coronary calcium could rule out ≥50% diameter coronary stenosis.
Methods: We identified 503 consecutive subjects without known CAD referred for CCTA at Cedars-Sinai Medical Center who had CAC of 0 (determined just prior to CCTA). Percent 10-year risk for cardiovascular events was determined by Framingham Risk Score (FRS). Two experienced readers interpreted CCTA to identify presence of plaque, plaque location, and segmental luminal diameter stenosis using a modified 17-segment coronary tree model.
Results: Of the 503 patients (mean age 53±12 years), 241 (48%) were men, and 153 (30%) were asymptomatic. Mean FRS for the overall, asymptomatic, and symptomatic populations were 6.6%, 7.5% and 6.1%, respectively. CCTA found no plaque in 476 patients (94.6%) and absence of ≥50% stenosis in 498 patients (99%). The overall predictive value of CAC of 0 for absence of ≥50% stenosis was 99%. Similarly high predictive values were found when the population was stratified by sex (99.2% for men and 98.9% for women), age (99.2% for <65 years-olds and 98.1% for ≥65 years-old), and presence of symptoms (99.3% for symptomatic and 98.9% for asymptomatic individuals).
Conclusions: In a population at low risk for future cardiovascular events, a CAC of zero robustly predicted absence of significant coronary artery stenosis.
- © 2011 by American Heart Association, Inc.