title: Incremental prognostic value of coronary artery calcium score versus CT angiography among symptomatic patients without known coronary artery disease.
abstract: OBJECTIVE
  To evaluate the prognostic value and test characteristics of coronary artery calcium (CAC) score for the identification of obstructive coronary artery disease (CAD) in comparison with coronary computed tomography angiography (CCTA) among symptomatic patients.
  
  
  METHODS
  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 ≥ 50% and ≥ 70% 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).
  
  
  RESULTS
  Among 1145 included patients, the mean age was 55 ± 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 ≥ 50% stenosis. The prevalence of ≥ 70% stenosis was 16%. Among 483 (42%) patients with CAC zero, 395 (82%) had normal CCTA, 81 (17%) <50% stenosis, and 7 (1.5%) ≥ 50% stenosis. 2 (0.4%) patients had ≥ 70% stenosis. For diagnosis of ≥ 50% stenosis, CAC had a sensitivity of 98% and specificity of 55%. The negative predictive value (NPV) for CAC was 99% for ≥ 50% stenosis and 99.6% for ≥ 70% stenosis by CCTA. There were no adverse events among the 7 patients with zero calcium and ≥ 50% CAD. For prediction of MACE, the c-statistic for clinical risk factors of 0.62 increased to 0.73 (p < 0.001) with CAC versus 0.77 (p = 0.02) with CCTA.
  
  
  CONCLUSIONS
  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.
authors: Non-Invasive Cardiovascular Imaging Program, Departments of Medicine and Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St, Boston, MA 02115, USA; Cardiology Service, Department of Medicine, Walter Reed National Military Medical Center, Bethesda, MD, USA.
authors: Edward
authors: E
authors: Hulten
authors: Non-Invasive Cardiovascular Imaging Program, Departments of Medicine and Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St, Boston, MA 02115, USA; Heart Institute (InCor), University of São Paulo, São Paulo, Brazil.
authors: Marcio Sommer
authors: MS
authors: Bittencourt
authors: Cardiac MR PET CT Program, Department of Radiology, Division of Cardiac Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
authors: Brian
authors: B
authors: Ghoshhajra
authors: Non-Invasive Cardiovascular Imaging Program, Departments of Medicine and Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St, Boston, MA 02115, USA.
authors: Daniel
authors: D
authors: O'Leary
authors: Non-Invasive Cardiovascular Imaging Program, Departments of Medicine and Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St, Boston, MA 02115, USA.
authors: Mitalee P
authors: MP
authors: Christman
authors: Johns Hopkins Ciccarone Center for the Prevention of Heart Disease, Baltimore, MD, USA.
authors: Michael J
authors: MJ
authors: Blaha
authors: Division of Cardiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
authors: Quynh
authors: Q
authors: Truong
authors: Non-Invasive Cardiovascular Imaging Program, Departments of Medicine and Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St, Boston, MA 02115, USA.
authors: Kyle
authors: K
authors: Nelson
authors: Non-Invasive Cardiovascular Imaging Program, Departments of Medicine and Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St, Boston, MA 02115, USA.
authors: Philip
authors: P
authors: Montana
authors: Non-Invasive Cardiovascular Imaging Program, Departments of Medicine and Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St, Boston, MA 02115, USA.
authors: Michael
authors: M
authors: Steigner
authors: Non-Invasive Cardiovascular Imaging Program, Departments of Medicine and Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St, Boston, MA 02115, USA.
authors: Frank
authors: F
authors: Rybicki
authors: Non-Invasive Cardiovascular Imaging Program, Departments of Medicine and Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St, Boston, MA 02115, USA.
authors: Jon
authors: J
authors: Hainer
authors: Cardiac MR PET CT Program, Department of Radiology, Division of Cardiac Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
authors: Thomas J
authors: TJ
authors: Brady
authors: Cardiac MR PET CT Program, Department of Radiology, Division of Cardiac Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
authors: Udo
authors: U
authors: Hoffmann
authors: Non-Invasive Cardiovascular Imaging Program, Departments of Medicine and Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St, Boston, MA 02115, USA.
authors: Marcelo F
authors: MF
authors: Di Carli
authors: Baptist Health South Florida, Miami, FL, USA.
authors: Khurram
authors: K
authors: Nasir
authors: Cardiac MR PET CT Program, Department of Radiology, Division of Cardiac Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
authors: Suhny
authors: S
authors: Abbara
authors: Non-Invasive Cardiovascular Imaging Program, Departments of Medicine and Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St, Boston, MA 02115, USA. Electronic address: rblankstein@partners.org.
authors: Ron
authors: R
authors: Blankstein
mesh_terms: D000328:Adult; D000368:Aged; D002114:Calcinosis / Q000000981:diagnostic imaging*; D002118:Calcium / Q000032:analysis*; D002318:Cardiovascular Diseases / Q000453:epidemiology; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D002118:Calcium
keywords: Atherosclerosis; Coronary artery calcium score; Coronary computed tomography angiography; Epidemiology