title: Measuring aortic valve coaptation surface area using three-dimensional transesophageal echocardiography.
abstract: BACKGROUND
  As aortic valve (AV) repairs become more sophisticated, surgeons need increasingly detailed information about the structure and function of this valve. Unlike two-dimensional transesophageal echocardiography (2D-TEE), using three-dimensional (3D)-TEE makes it possible to image the entire AV. We hypothesized that measuring coaptation surface area (CoapSA) would be feasible and reproducible, and CoapSA would decrease in patients with aortic insufficiency.
  
  
  METHODS
  We developed a new technique to calculate the AV-CoapSA using 3D-TEE. We measured the coaptation surfaces between the right coronary cusp/left coronary cusp, right coronary cusp/non-coronary cusp, and left coronary cusp/non-coronary cusp in ten normal AVs and ten AVs with moderate-severe aortic insufficiency (AI). Since computer models have previously shown that CoapSA is trapezoidal, we used the formula: trapezoid area = length × (medial coaptation height + lateral coaptation height)/2. The total CoapSA was calculated by adding all three areas. To adjust for valve size, we indexed the value to the diameter of the ventricular aortic junction (VAJ). Measurements were performed by two observers.
  
  
  RESULTS
  The intra-observer correlation was 0.84 for one observer (P < 0.0001) and 0.93 for the other (P < 0.0001). The inter-observer correlation was 0.87 (P < 0.0001). In normal valves, the CoapSA [mean total (standard deviation)] was significantly greater than in the insufficient valves [1.61 (0.31) cm(2) vs 1.03 (0.22) cm(2), respectively; P < 0.001]. After indexing for the VAJ diameter, the total CoapSA remained significantly greater in normal valves than in insufficient valves.
  
  
  CONCLUSIONS
  In this proof of concept study, we present a new and innovative technique to measure AV-CoapSA using 3D-TEE. It is reproducible and shows decreased CoapSA in patients with AI. Coaptation surface area may provide insight into mechanisms of AI and may have predictive value following AV repair.
authors.affiliation: Division of Cardiac Anesthesiology, University of Ottawa Heart Institute, ON, Canada. bsohmer@ottawaheart.ca
authors.forename: Benjamin
authors.initials: B
authors.lastname: Sohmer
authors.forename: Christopher
authors.initials: C
authors.lastname: Hudson
authors.forename: Juliet
authors.initials: J
authors.lastname: Atherstone
authors.forename: A Stephane
authors.initials: AS
authors.lastname: Lambert
authors.forename: Michel
authors.initials: M
authors.lastname: Labrosse
authors.forename: Munir
authors.initials: M
authors.lastname: Boodhwani
mesh_terms: D000368:Aged; D001021:Aortic Valve / Q000000981:diagnostic imaging*; D001022:Aortic Valve Insufficiency / Q000000981:diagnostic imaging* / Q000601:surgery*; D003331:Coronary Vessels / Q000000981:diagnostic imaging; D019560:Echocardiography, Three-Dimensional / Q000379:methods; D017548:Echocardiography, Transesophageal / Q000379:methods*; D005260:Female; D019918:Heart Valve Prosthesis Implantation / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011446:Prospective Studies; D012016:Reference Values; D015203:Reproducibility of Results