title: Does coronary CT angiography improve risk stratification over coronary calcium scoring in symptomatic patients with suspected coronary artery disease? Results from the prospective multicenter international CONFIRM registry.
abstract: OBJECTIVE
  The prognostic value of coronary artery calcium (CAC) scoring is well established and has been suggested for use to exclude significant coronary artery disease (CAD) for symptomatic individuals with CAD. Contrast-enhanced coronary computed tomographic angiography (CCTA) is an alternative modality that enables direct visualization of coronary stenosis severity, extent, and distribution. Whether CCTA findings of CAD add an incremental prognostic value over CAC in symptomatic individuals has not been extensively studied.
  
  
  RESULTS
  We prospectively identified symptomatic patients with suspected but without known CAD who underwent both CAC and CCTA. Symptoms were defined by the presence of chest pain or dyspnoea, and pre-test likelihood of obstructive CAD was assessed by the method of Diamond and Forrester (D-F). CAC was measured by the method of Agatston. CCTAs were graded for obstructive CAD (>70% stenosis); and CAD plaque burden, distribution, and location. Plaque burden was determined by a segment stenosis score (SSS), which reflects the number of coronary segments with plaque, weighted for stenosis severity. Plaque distribution was established by a segment-involvement score (SIS), which reflects the number of segments with plaque irrespective of stenosis severity. Finally, a modified Duke prognostic index-accounting for stenosis severity, plaque distribution, and plaque location-was calculated. Nested Cox proportional hazard models for a composite endpoint of all-cause mortality and non-fatal myocardial infarction (D/MI) were employed to assess the incremental prognostic value of CCTA over CAC. A total of 8627 symptomatic patients (50% men, age 56 ± 12 years) followed for 25 months (interquartile range 17-40 months) comprised the study cohort. By CAC, 4860 (56%) and 713 (8.3%) patients had no evident calcium or a score of >400, respectively. By CCTA, 4294 (49.8%) and 749 (8.7%) had normal coronary arteries or obstructive CAD, respectively. At follow-up, 150 patients experienced D/MI. CAC improved discrimination beyond D-F and clinical variables (area under the receiver-operator characteristic curve 0.781 vs. 0.788, P = 0.004). When added sequentially to D-F, clinical variables, and CAC, all CCTA measures of CAD improved discrimination of patients at risk for D/MI: obstructive CAD (0.82, P < 0.001), SSS (0.81, P < 0.001), SIS (0.81, P = 0.003), and Duke CAD prognostic index (0.82, P < 0.0001).
  
  
  CONCLUSIONS
  In symptomatic patients with suspected CAD, CCTA adds incremental discriminatory power over CAC for discrimination of individuals at risk of death or MI.
authors: Department of Medicine, Wayne State University, Henry Ford Hospital, Detroit, MI, USA.
authors: Mouaz H
authors: MH
authors: Al-Mallah
authors: Waqas
authors: W
authors: Qureshi
authors: Fay Y
authors: FY
authors: Lin
authors: Stephan
authors: S
authors: Achenbach
authors: Daniel S
authors: DS
authors: Berman
authors: Matthew J
authors: MJ
authors: Budoff
authors: Tracy Q
authors: TQ
authors: Callister
authors: Hyuk-Jae
authors: HJ
authors: Chang
authors: Filippo
authors: F
authors: Cademartiri
authors: Kavitha
authors: K
authors: Chinnaiyan
authors: Benjamin J W
authors: BJ
authors: Chow
authors: Victor Y
authors: VY
authors: Cheng
authors: Augustin
authors: A
authors: Delago
authors: Millie
authors: M
authors: Gomez
authors: Martin
authors: M
authors: Hadamitzky
authors: Joerg
authors: J
authors: Hausleiter
authors: Philipp A
authors: PA
authors: Kaufmann
authors: Jonathon
authors: J
authors: Leipsic
authors: Erica
authors: E
authors: Maffei
authors: Gilbert
authors: G
authors: Raff
authors: Leslee J
authors: LJ
authors: Shaw
authors: Todd C
authors: TC
authors: Villines
authors: Ricardo C
authors: RC
authors: Cury
authors: Gudrun
authors: G
authors: Feuchtner
authors: Fabian
authors: F
authors: Plank
authors: Yong-Jin
authors: YJ
authors: Kim
authors: Allison M
authors: AM
authors: Dunning
authors: James K
authors: JK
authors: Min
mesh_terms: D000328:Adult; D000368:Aged; D002118:Calcium / Q000378:metabolism; D015331:Cohort Studies; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000401:mortality* / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000401:mortality* / Q000503:physiopathology; D058226:Plaque, Atherosclerotic / Q000000981:diagnostic imaging / Q000503:physiopathology; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012042:Registries; D018570:Risk Assessment; D015996:Survival Rate; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D003287:Contrast Media; D002118:Calcium
keywords: coronary CT angiography; coronary artery calcium; coronary artery disease; prognosis; symptomatic