title: Transesophageal echocardiographic evaluation of native aortic valve area: utility of the double-envelope technique.
abstract: OBJECTIVE
  To assess the accuracy of aortic valve area (AVA) calculations using the continuity equation with data obtained from the double envelope (DE) (simultaneously obtained left ventricular outflow tract [V1]) and aortic valve [V2] velocities) during intraoperative transesophageal echocardiography (TEE).
  
  
  METHODS
  Prospective study; measurements were performed on-line.
  
  
  METHODS
  University hospital.
  
  
  METHODS
  Cardiac and noncardiac surgical patients (n = 75) with recent aortic valve assessment (<3 months) undergoing general anesthesia or endotracheal intubation.
  
  
  METHODS
  Intraoperative AVA was measured by the continuity equation using the DE technique (DE/TEE) and by planimetry (PL/TEE). Left ventricular outflow tract diameter was obtained from midesophageal views, whereas subvalvular (V1) and valvular (V2) velocities were obtained simultaneously using continuous-wave Doppler from transgastric views. V1 was also obtained using pulsed-wave Doppler. Measurements were compared with AVA obtained preoperatively by the Gorlin equation during cardiac catheterization (G/CATH) or by transthoracic echocardiography using the traditional continuity equation (C/TTE) (nonsimultaneously obtained V1 and V2).
  
  
  RESULTS
  A DE was obtained in 73 of 75 patients (97%). Four patients had atrial fibrillation at the time of the examination, whereas the rest were in sinus rhythm. PL/TEE was performed in 54 of 71 patients with sinus rhythm (76%). Agreement was good between DE/TEE and G/CATH (mean bias, 0.02 cm(2) [SD, 0.24 cm(2)]), and C/TTE (mean bias, -0.05 cm(2) [SD, 0.16 cm(2)]). Agreement was not as good between PL/TEE and G/CATH (mean bias, -0.07 cm(2) [SD, 0.28 cm(2)]) and C/TTE (mean bias, -0.13 cm(2) [SD, 0.30 cm(2)]). V1 obtained by pulsed-wave Doppler and with DE closely agreed (mean bias, 0.01 m/sec [SD, 0.05 m/sec]).
  
  
  CONCLUSIONS
  TEE evaluation of native AVA using the DE technique is feasible and in good agreement with that obtained by C/TTE and G/CATH. Compared with DE/TEE, PL/TEE did not agree as well. Use of DE/TEE should simplify the continuity equation and may minimize errors resulting from beat-to-beat variability in stroke volume.
authors: Departments of Anesthesia and Cardiology, Beth Israel-Deaconess Medical Center, Boston, MA, USA.
authors: A D
authors: AD
authors: Maslow
authors: J
authors: J
authors: Mashikian
authors: J M
authors: JM
authors: Haering
authors: S
authors: S
authors: Heindel
authors: P
authors: P
authors: Douglas
authors: R
authors: R
authors: Levine
mesh_terms: D000368:Aged; D001021:Aortic Valve / Q000000981:diagnostic imaging*; D003326:Coronary Circulation / Q000502:physiology; D017548:Echocardiography, Transesophageal / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D011446:Prospective Studies; D016277:Ventricular Function, Left