Retrospective cohort study at two large hospitals, including all symptomatic patients without prior CAD who underwent both CCTA and CAC. Accuracy of CAC for the identification of 鈮?0% and 鈮?0% stenosis by CCTA was evaluated. Prognostic value of CAC and CCTA were compared for prediction of major adverse cardiovascular events (MACE, defined as non-fatal myocardial infarction, cardiovascular death, late coronary revascularization (>90 days), and unstable angina requiring hospitalization).
Among 1145 included patients, the mean age was 55聽卤聽12 years and median follow up 2.4 (IQR: 1.5-3.5) years. Overall, 406 (35%) CCTA were normal, 454 (40%) had <50% stenosis, and 285 (25%) had 鈮?0% stenosis. The prevalence of 鈮?0% stenosis was 16%. Among 483 (42%) patients with CAC zero, 395 (82%) had normal CCTA, 81 (17%) <50% stenosis, and 7 (1.5%)聽鈮ヂ?0% stenosis. 2 (0.4%) patients had 鈮?0% stenosis. For diagnosis of 鈮?0% stenosis, CAC had a sensitivity of 98% and specificity of 55%. The negative predictive value (NPV) for CAC was 99% for 鈮?0% stenosis and 99.6% for 鈮?0% stenosis by CCTA. There were no adverse events among the 7 patients with zero calcium and 鈮?0% CAD. For prediction of MACE, the c-statistic for clinical risk factors of 0.62 increased to 0.73 (p聽<聽0.001) with CAC versus 0.77 (p聽=聽0.02) with CCTA.
Among symptomatic patients with CAC zero, a 1-2% prevalence of potentially obstructive CAD occurs, although this finding was not associated with future coronary revascularization or adverse prognosis within 2 years.