title: Accuracy of Doppler-echocardiographic parameters for the detection of aortic bileaflet mechanical prosthetic valve dysfunction.
abstract: OBJECTIVE
  In vitro and in vivo studies were performed to evaluate the diagnostic accuracy of the different Doppler-echocardiographic parameters proposed in the American Society of Echocardiography guidelines to identify dysfunction of bileaflet mechanical valves (BMV) in the aortic position.
  
  
  RESULTS
  Two models of BMV (St Jude HP, MCRI On-X) of different sizes (21;23;25;27 mm) were tested in vitro under a wide range of cardiac outputs (3-7 L/min). The motion of one or both leaflets was restricted to induce a mild (25% restriction in total valve orifice area) and moderate-to-severe (50% restriction in total valve area). Doppler-echocardiographic parameters of valve function were also measured in 17 patients with BMV of whom 4 had valve dysfunction confirmed by cinefluoroscopy. The specificity of all the parameters was high (in vitro: 83-100%; in vivo: 69-100%), but the sensitivity was low (range: 0-83% and 25-100%, respectively). A higher cut-off value for the ratio of peak left ventricular outflow tract velocity to peak aortic velocity or Doppler velocity index (DVI) (<0.35 instead of 0.3 or 0.25) improved the sensitivity (>90%) for the detection of moderate-to-severe dysfunction but remained low for mild dysfunction (50%). Furthermore, a difference of normal reference effective orifice area (EOA) minus measured EOA (EOA-D) >1 standard deviation identified mild and moderate-to-severe dysfunction with sensitivity of 61 and 100%, respectively.
  
  
  CONCLUSIONS
  The Doppler-echocardiographic parameters and criteria proposed in the guidelines lack sensitivity for the detection of BMV dysfunction. The utilization of a DVI < 0.35 or an EOA-D > 1 SD improved the sensitivity (>90%) for the detection of moderate-to-severe dysfunction, but the sensitivity remained suboptimal (<65%) for detection of mild dysfunction.
authors.affiliation: Laboratory of Cardiovascular Fluid Dynamics, Department of Mechanical and Industrial Engineering, Concordia University, 1455 de Maisonneuve Blvd W, Montréal, QC, Canada H3G 1M8.
authors.forename: Othman
authors.initials: O
authors.lastname: Smadi
authors.forename: Julio
authors.initials: J
authors.lastname: Garcia
authors.forename: Philippe
authors.initials: P
authors.lastname: Pibarot
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Gaillard
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Hassan
authors.forename: Lyes
authors.initials: L
authors.lastname: Kadem
mesh_terms: D001021:Aortic Valve / Q000000981:diagnostic imaging*; D002302:Cardiac Output; D015150:Echocardiography, Doppler; D004867:Equipment Design; D005260:Female; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D006801:Humans; D008297:Male; D017410:Practice Guidelines as Topic; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012680:Sensitivity and Specificity
keywords: Aortic stenosis; Doppler echocardiography; Prosthetic heart valve