Abstract Background Coronary artery calcium (CAC) scanning can be performed using non-contrast computed tomography to predict cardiovascular events, but has less value for risk stratification in symptomatic patients. Objective To identify and validate predictors of significant coronary obstruction (SCO) in symptomatic patients without coronary artery calcification. Methods A total of 4,258 participants were screened from the CORE64 and CORE320 studies that enrolled patients referred for invasive angiography, and from the Quanta Registry that included patients referred for coronary computed tomography […]