title: Fractional flow reserve derived from coronary CT angiography: variation of repeated analyses.
abstract: BACKGROUND
  Fractional flow reserve (FFR) is the standard of reference for assessing the hemodynamic significance of coronary stenoses in patients with stable coronary artery disease. Noninvasive FFR derived from coronary CT angiography (FFRCT) is a promising new noninvasive method for assessing the physiologic significance of epicardial stenoses. The reproducibility of FFRCT has not yet been established.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the variation of repeated analyses of FFRCT per se and in the context of the reproducibility of repeated FFR measurements.
  
  
  METHODS
  Coronary CT angiography and invasive coronary angiography with repeated FFR measurements were performed in 28 patients (58 vessels) with suspected stable coronary artery disease. Based on the coronary CT angiography data set, FFRCT analyses were performed twice by 2 independent blinded analysts.
  
  
  RESULTS
  In 12 of 58 (21%) vessels FFR was ≤ 0.80. The standard deviation for the difference between first and second FFRCT analyses was 0.034 vs 0.033 for FFR repeated measurements (P = .722). Limits of agreement were -0.06 to 0.08 for FFRCT and -0.07 to 0.06 for FFR. The coefficient of variation of FFRCT (CVFFRct) was 3.4% (95% confidence interval [CI], 1.4%-4.6%) vs 2.7% (95% CI, 1.8%-3.3%) for FFR. In vessels with mean FFR ranging between 0.70 and 0.90 (n = 25), the difference between the first and second FFRCT analyses was 0.035 and FFR repeated measurements was 0.043 (P = .357), whereas CVFFRct was 3.3% (95% CI, 1.5%-4.3%) and coefficient of variation for FFR was 3.6% (95% CI, 2.3%-4.6%).
  
  
  CONCLUSIONS
  The reproducibility of both repeated FFRCT analyses and repeated FFR measurements is high.
authors.affiliation: Department of Cardiology, Aarhus University Hospital, Brendstrupgaardsvej 100, Skejby, 8200 Aarhus N, Denmark. Electronic address: sargau@rm.dk.
authors.forename: Sara
authors.initials: S
authors.lastname: Gaur
authors.affiliation: Harrington Heart and Vascular Institute, Case Medical Center, Cleveland, OH, USA.
authors.forename: Hiram G
authors.initials: HG
authors.lastname: Bezerra
authors.affiliation: Department of Cardiology, Aarhus University Hospital, Brendstrupgaardsvej 100, Skejby, 8200 Aarhus N, Denmark.
authors.forename: Jens F
authors.initials: JF
authors.lastname: Lassen
authors.affiliation: Department of Cardiology, Aarhus University Hospital, Brendstrupgaardsvej 100, Skejby, 8200 Aarhus N, Denmark.
authors.forename: Evald H
authors.initials: EH
authors.lastname: Christiansen
authors.affiliation: Harrington Heart and Vascular Institute, Case Medical Center, Cleveland, OH, USA.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Tanaka
authors.affiliation: Department of Cardiology, Aarhus University Hospital, Brendstrupgaardsvej 100, Skejby, 8200 Aarhus N, Denmark.
authors.forename: Jesper M
authors.initials: JM
authors.lastname: Jensen
authors.affiliation: Department of Cardiology, Golden Jubilee National Hospital, Glasgow, Scotland.
authors.forename: Keith G
authors.initials: KG
authors.lastname: Oldroyd
authors.affiliation: Department of Radiology, St. Paul's Hospital, Vancouver, BC, Canada.
authors.forename: Jonathon
authors.initials: J
authors.lastname: Leipsic
authors.affiliation: Department of Cardiology, University of Erlangen, Erlangen, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Achenbach
authors.affiliation: Department of Cardiology, Aarhus University Hospital, Brendstrupgaardsvej 100, Skejby, 8200 Aarhus N, Denmark.
authors.forename: Anne K
authors.initials: AK
authors.lastname: Kaltoft
authors.affiliation: Department of Cardiology, Aarhus University Hospital, Brendstrupgaardsvej 100, Skejby, 8200 Aarhus N, Denmark.
authors.forename: Hans Erik
authors.initials: HE
authors.lastname: Bøtker
authors.affiliation: Department of Cardiology, Aarhus University Hospital, Brendstrupgaardsvej 100, Skejby, 8200 Aarhus N, Denmark.
authors.forename: Bjarne L
authors.initials: BL
authors.lastname: Nørgaard
mesh_terms: D000368:Aged; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed
keywords: Computational fluid dynamics; Computed tomography angiography; Coronary angiography; Fractional flow reserve; Invasive coronary angiography; Reproducibility