Abstract 5795: 2D vs 3D Transesophageal Echo in the Assessment of the Aortic Annulus for Transcatheter Aortic Valve Implantation
Transcatheter aortic valve implantation (TAVI) is a relatively new procedure, currently for those in whom conventional surgery is too high risk. Preliminary data has been encouraging and a number of clinical trials are ongoing. Accurate imaging is mandated for TAVI, not least in the assessment of aortic annular size. We are utilising 3D transesophageal echo (TEE) in our TAVI programme and wanted to see if there was a discrepancy between annular measurements made using 2D and 3D TEE. Measurements on 16 patients (6 male) who underwent successful TAVI were made. Annular diameters were taken on 2D and 3D images by 2 independent observers. The distance between the insertion points of the leaflets was taken in mid systole. 2D measurements were made using the mid-esophageal long axis view. 3D measurements were from a full volume or live 3D acquisition, using a 3D viewer to line the valve up in orthogonal planes (see figure⇓). Annular measurements were possible using both 2D and 3D in all patients. Interobserver agreement was good for both techniques with correlation coefficients of 0.81 for 2D and 0.89 for 3D. Intraobserver correlation was 0.86 for 2D and 0.90 for 3D. When the annular measurements of the 2 readers were combined the mean obtained by 3D was significantly larger than that obtained using 2D: 20.7 mm (SD 2.1) for 2D and 21.5 mm (SD 2.1) for 3D. The difference was 0.8mm (p=0.02). Aortic annular measurements using both 2D and 3D TEE show very good reliability and reproducibility. However, 2D TEE appears to underestimate aortic annular diameter when compared to 3D. As TAVI becomes more prevalent this discrepancy may become important in the sizing process.