3D transthoracic and transesophageal echocardiographic data
All examinations were performed with the GE Vivid E95 echo machine (GE Vingmed Ultrasound, Horten, Norway), using the 4Vc TTE and the 6VT-D TOE probes. All data were stored and retrospectively analyzed with the EchoPAC v.203 workstation.
For 3D TTE measurements, MV was demonstrated in four-chamber view and 4D “en face” views were acquired by using “4D zoom prepare” method, with a frame rate of more than 12 volumes per second (vps). For TOE measurements, the MV was visualized in the commissural view (approx. 60-70o) and 4D “en face” MV views were captured by using “4D zoom prepare” method, also with a frame rate of more than 12vps. In patients with sinus rhythm, multi-beat acquisitions were used in order to achieve high temporal and spatial resolution, whereas single-beat acquisition was used in patients with atrial fibrillation (AF) or other rhythm abnormalities, and in patients that were unable to perform a satisfying breath hold.
All data were stored in an EchoPAC workstation and 3D datasets were analyzed using the 4D AutoMVQ software. This is a semi-automated software dedicated for mitral annulus and leaflets analysis. The operator performs the following three steps for MV assessment: 1) alignment of the commissural and long axis views so that the vertical axis crosses through the center of the MV and the horizontal axis is parallel to the MV, 2) setting the six landmark points of MV annulus, aortic valve and leaflet coaptation point and 3) review of the MV model that is generated automatically by the software. In the final screen, different layouts of the mitral valve can be demonstrated (2D views, volume rendering en face view and MV model) along with all the measurements for the annulus and the leaflets. (Figure 1)
The variables that were analyzed and compared in our protocol are: 1) 2D & 3D annulus area, 2) annulus perimeter, 3) anterior-posterior diameter, 4) medial-lateral diameter, 5) commissural diameter, 6) inter-trigonal diameter, 7) aorto-mitral angle, 8) anterior leaflet area, 9) posterior leaflet area, 10) anterior leaflet length, 11) posterior leaflet length, 12) tenting height, 13) tenting area and 14) tenting volume.