title: Measurement of aortic valve calcification using multislice computed tomography: correlation with haemodynamic severity of aortic stenosis and clinical implication for patients with low ejection fraction.
abstract: BACKGROUND
  Measurement of the degree of aortic valve calcification (AVC) using electron beam computed tomography (EBCT) is an accurate and complementary method to transthoracic echocardiography (TTE) for assessment of the severity of aortic stenosis (AS). Whether threshold values of AVC obtained with EBCT could be extrapolated to multislice computed tomography (MSCT) was unclear and AVC diagnostic value in patients with low ejection fraction (EF) has never been specifically evaluated.
  
  
  METHODS
  Patients with mild to severe AS underwent prospectively within 1 week MSCT and TTE. Severe AS was defined as an aortic valve area (AVA) of less than 1 cm(2). In 179 patients with EF greater than 40% (validation set), the relationship between AVC and AVA was evaluated. The best threshold of AVC for the diagnosis of severe AS was then evaluated in a second subset (testing set) of 49 patients with low EF (≤40%). In this subgroup, AS severity was defined based on mean gradient, natural history or dobutamine stress echocardiography.
  
  
  RESULTS
  Correlation between AVC and AVA was good (r=-0.63, p<0.0001). A threshold of 1651 arbitrary units (AU) provided 82% sensitivity, 80% specificity, 88% negative-predictive value and 70% positive-predictive value. In the testing set (patients with low EF), this threshold correctly differentiated patients with severe AS from non-severe AS in all but three cases. These three patients had an AVC score close to the threshold (1206, 1436 and 1797 AU).
  
  
  CONCLUSIONS
  In this large series of patients with a wide range of AS, AVC was shown to be well correlated to AVA and may be a useful adjunct for the evaluation of AS severity especially in difficult cases such as patients with low EF.
authors: Cardiology Department, AP-HP, Bichat Hospital, Paris, France.
authors: Caroline
authors: C
authors: Cueff
authors: Jean-Michel
authors: JM
authors: Serfaty
authors: Claire
authors: C
authors: Cimadevilla
authors: Jean-Pierre
authors: JP
authors: Laissy
authors: Dominique
authors: D
authors: Himbert
authors: Florence
authors: F
authors: Tubach
authors: Xavier
authors: X
authors: Duval
authors: Bernard
authors: B
authors: Iung
authors: Maurice
authors: M
authors: Enriquez-Sarano
authors: Alec
authors: A
authors: Vahanian
authors: David
authors: D
authors: Messika-Zeitoun
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001783:Blood Flow Velocity / Q000502:physiology; D002114:Calcinosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D012680:Sensitivity and Specificity; D013318:Stroke Volume / Q000502:physiology; D014057:Tomography, X-Ray Computed / Q000379:methods*