Real-time three-dimensional transesophageal echocardiography in patients with secundum atrial septal defects: outcomes following transcatheter closure.

BACKGROUND

Successful transcatheter closure of atrial septal defects (ASDs) requires the accurate assessment of defect size and morphology. Assessment of ASD anatomy may be difficult by two-dimensional (2D) echocardiography. The aim of this study was to test the hypothesis that real-time three-dimensional (3D) transesophageal echocardiography (TEE) may provide more accurate morphologic assessment of ASDs than multiplane 2D TEE.

METHODS

Twenty-four patients with ASDs were imaged using 2D and real-time 3D TEE. ASD shape and size were assessed using 3D TEE retrospectively. Maximal ASD dimensions obtained by 3D TEE were compared with unstretched and balloon-stretched dimensions on 2D TEE. Planimetered defect area by 3D TEE was compared with area calculated using the ellipse formula from 2D imaging. Twenty of the 24 patients underwent transcatheter ASD closure. Closure device size was based on findings on 2D TEE. Follow-up was conducted by 2D transthoracic echocardiography.

RESULTS

Of the 24 ASDs, 6 (25%) were circular, 10 (42%) were oval, and 8 (33%) were complex in shape. The mean maximal dimension was larger by 3D TEE compared with 2D TEE (1.8 ± 0.8 vs 1.5 ± 0.6 cm; P < .05). There was no difference in the mean area measured by either modality, but for complex-shaped defects, area measured by 3D TEE was larger than that by 2D TEE (2.8 ± 1.3 vs 1.7 ± 1.4 cm(2); P < .05). Follow-up transthoracic echocardiography was available for 19 of the 20 patients undergoing transcatheter closure. Nine patients had residual right-to-left shunting 1 to 6 months after ASD closure, and the majority of these were complex in shape. In patients with residual shunting, ASD area by 3D TEE was 27% larger than by 2D TEE, whereas in patients without residual shunting, there was significantly less discrepancy between 3D and 2D areas (19%; P = .0027).

CONCLUSIONS

Three-dimensional TEE can identify ASD shape. Maximal dimensions on 3D TEE were well correlated with balloon-stretched 2D dimensions. Two-dimensional TEE can underestimate the area of complex-shaped ASDs, which may result in residual right-to-left shunting.