title: Reliability of new and old Doppler echocardiographic indexes of the severity of aortic stenosis in patients with a low cardiac output.
abstract: BACKGROUND
  In addition to the conventional "flow-corrected" parameters (continuity equation and aortic valve resistance), new and simpler Doppler echocardiographic indexes of the severity of aortic stenosis have recently been introduced. These measures can be classified as "function-corrected" indexes (fractional shortening-velocity ratio and ejection fraction-velocity ratio) and "pressure-corrected" indexes (percent stroke work loss). Little information however is available about the diagnostic accuracy of each of these parameters in identifying patients with severe aortic stenosis in low-flow states, in which the diagnosis and clinical decision-making are more difficult and challenging.
  
  
  METHODS
  We analyzed 161 patients with aortic stenosis (96 males, 65 females, mean age 68 +/- 9 years) and a low cardiac output (thermodilution cardiac index < or = 2.5 l/min/m2). All patients underwent both cardiac catheterization and echocardiography within 48 hours one of the other. The invasive Gorlin valve area was used as gold standard (severe aortic stenosis = Gorlin < or = 0.8 cm2). Echocardiographic indexes were assessed by an investigator who was unaware of the hemodynamic findings.
  
  
  RESULTS
  The mean Gorlin aortic valve area was 0.7 +/- 0.3 cm2; cardiac catheterization allowed the identification of 129 patients with severe aortic stenosis and of 32 with mild-to-moderate aortic stenosis. The diagnostic accuracy of the Doppler gradient alone was low (sensitivity 55%). The best linear correlation with the Gorlin value was found using the "function-corrected" ejection fraction-velocity ratio (r = 0.85). Similarly, the best combination of sensitivity and specificity in identifying patients with severe aortic stenosis, as assessed by cardiac catheterization, was observed using the ejection fraction-velocity ratio (sensitivity 87%, specificity 88%).
  
  
  CONCLUSIONS
  In patients with aortic stenosis and a low cardiac output, the "function-corrected" ejection fraction-velocity ratio offers the better diagnostic accuracy, as compared with the cardiac catheterization valve area calculation.
authors.affiliation: Division of Cardiology, A.R.C., S. Maria degli Angeli Hospital, Pordenone, Italy. antcant@adriacom.it
authors.forename: Francesco
authors.initials: F
authors.lastname: Antonini-Canterin
authors.forename: Guoqian
authors.initials: G
authors.lastname: Huang
authors.forename: Eugenio
authors.initials: E
authors.lastname: Cervesato
authors.forename: Pompilio
authors.initials: P
authors.lastname: Faggiano
authors.forename: Daniela
authors.initials: D
authors.lastname: Pavan
authors.forename: Rita
authors.initials: R
authors.lastname: Piazza
authors.forename: Claudio
authors.initials: C
authors.lastname: Burelli
authors.forename: Matteo
authors.initials: M
authors.lastname: Cassin
authors.forename: Franco
authors.initials: F
authors.lastname: Macor
authors.forename: Fabio
authors.initials: F
authors.lastname: Zardo
authors.forename: Gian Luigi
authors.initials: GL
authors.lastname: Nicolosi
mesh_terms: D000368:Aged; D001021:Aortic Valve / Q000000981:diagnostic imaging; D001024:Aortic Valve Stenosis / Q000150:complications / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001783:Blood Flow Velocity; D006328:Cardiac Catheterization; D002303:Cardiac Output, Low / Q000150:complications / Q000175:diagnosis / Q000000981:diagnostic imaging*; D015150:Echocardiography, Doppler; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D009200:Myocardial Contraction; D012372:ROC Curve; D012680:Sensitivity and Specificity