Three-Dimensional Echocardiography Compared With Computed Tomography to Determine Mitral Annulus Size Before Transcatheter Mitral Valve Implantation

Background-Previously, through the use of computed tomography (CT), it has been proposed that D-shaped versus saddleshaped mitral annulus (MA) segmentation is more biomechanically appropriate to determine transcatheter mitral valve implantation size and eligibility. Methods and Results-Forty-one patients with severe mitral regurgitation being considered for transcatheter mitral valve implantation who had undergone cardiac CT and 3-dimensional transesophageal echocardiography (3D-TEE) were retrospectively evaluated. A standardized segmentation protocol for the D-shaped MA was developed using Philips Q-Laboratory mitral valve quantification software. MA dimensions were compared using Spearman's rank correlation and Bland-Altman analysis. Inter-and intraobserver agreement was quantified by intraclass correlation coefficient and Bland-Altman analysis. Mean age was 77 +/- 14 years; 71% male (n = 29); mitral regurgitation pathogenesis was functional in 54% (n = 22) and myxomatous in 46% (n = 19). Mean MA area and circumference by 3D-TEE and CT were 11.3 +/- 2.7 versus 11.4 +/- 3.0 (P = 0.67) and 124.1 +/- 15.6 versus 123.9 +/- 15.5 (P = 0.79), respectively, with excellent correlation between modalities (r = 0.84 and r = 0.86; P< 0.0001) and no systematic bias (-0.20 +/- 1.8 cm(2) [-3.7 cm(2); 3.3 cm(2)], 0.37 +/- 9 mm [-18.0 mm; 17.27 mm]). Mean septal-to-lateral and inter-trigone distances by 3D-TEE and CT were 33.2 +/- 4.7 versus 32.5 +/- 4.4 (P = 0.24) and 31.7 +/- 3.5 versus 32.6 +/- 3.6 (P = 0.06), respectively, with good correlation (r = 0.69 and r = 0.71; P < 0.0001) and no systematic bias (0.77 +/- 3.8 mm [-6.7 mm; 8.2 mm], -1.5 +/- 3.1 mm [-4.6 mm; 7.6 mm]). There was excellent intra-and interobserver agreement according to intraclass correlation coefficients >0.90 for all parameters. Conclusions-Similar to cardiac CT, 3D-TEE allows for D-shaped MA segmentation with no systematic difference in MA dimensions between modalities. This study supports the utilization of 3D-TEE as a complementary tool to CT assessment of the D-shaped MA to determine transcatheter mitral valve implantation size.