title: Analysis of variability and reproducibility of echocardiography measurements in valvular aortic valve stenosis.
abstract: BACKGROUND
  Doppler echocardiography is the most frequent method for detecting and evaluating the severity of valvular aortic stenosis. The aim of this study was to assess the variability and reproducibility of echocardiographic parameters including aortic valve area (AVA), peak aortic jet velocity (V(max)), velocity ratio (V(LVOT)/V(max)), peak gradient (G(max)) and mean gradient (G(mean)) in aortic stenosis (AS) patients.
  
  
  METHODS
  Doppler echocardiograms were obtained from 150 randomly selected patients (56.7% male; mean age 73 +/- 9 years) with asymptomatic moderate aortic valve stenosis. The echocardiographic measurements were performed by two independent level III (expert) blinded observers. To assess intra-observer variability, we evaluated parameters of AS progression at two different times (mean of two weeks after the first examination).
  
  
  RESULTS
  For intra-observer variability (observer 1), the variation and reproducibility coefficients were, respectively, 1.88% and 0.16 m/s for V(max), 2.08% and 0.14 for V(LVOT)/V(max) 2.05% and 0.18 cm2 for AVA, 3.89% and 5.18 mmHg for G(max) and 7.87% and 6.30 mmHg for G(mean). For inter-observer variability, the variation and reproducibility coefficients were, respectively, 2.00% and 0.14 m/s for V(max), 2.91% and 0.14 for V(LVOT)/V(max), 7.67% and 0.16 cm2 for AVA, 8.53% and 7.06 mmHg for G(mean) and 3.90% and 5.58 mmHg for G(max). Both intra- and inter-observer studies showed excellent intraclass correlation coefficients (ICC) for all echocardiographic parameters (ICC ranged from 0.943 to 0.990 for intra-observer variability and from 0.955 to 0.992 for interobserver variability).
  
  
  CONCLUSIONS
  Doppler echocardiographic measurements of AVA, V(max), G(max) and G(mean) are highly reproducible when performed by expert observers. Of all echocardiographic parameters, V(max) and V(LVOT)/V(max) showed the best variability and reproducibility, and thus constitute reliable tools for clinical and research purposes in aortic stenosis diagnosis and follow-up.
authors.affiliation: Oporto University School of Medicine, Oporto, Portugal. luismoura@med.up.pt
authors.forename: Luís M
authors.initials: LM
authors.lastname: Moura
authors.forename: Sandra F
authors.initials: SF
authors.lastname: Ramos
authors.forename: Fausto J
authors.initials: FJ
authors.lastname: Pinto
authors.forename: Isabel M
authors.initials: IM
authors.lastname: Barros
authors.forename: F
authors.initials: F
authors.lastname: Rocha-Gonçalves
mesh_terms: D000368:Aged; D001021:Aortic Valve / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001783:Blood Flow Velocity; D004452:Echocardiography / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D015203:Reproducibility of Results; D013997:Time Factors