The role of 'halo sign' for the accurate quantification of atrial septal defect size with 3D TEE.

In patients undergoing percutaneous closure of secundum atrial septal defect, the device selection is decided based on three-dimensional transesophageal echocardiography (3D TEE) measurements and two-dimensional balloon stretched diameter measurements; more importantly balloon sizing. The purpose of the study was to assess whether in patients with "halo-sign", defined as increased tissue thickness at the edge of the ASD rims, there is an agreement between 3D TEE and 2D balloon stretched diameter aiming to avoidance of balloon sizing. Forty consecutive patients who underwent closure of a single, without complex anatomy ASD were included. 3D and 2D TEE datasets were acquired and analyzed offline. Planimetry was used to calculate circumference derived diameter of ASD from 3D datasets. Patients were classified according to the presence of the "halo sign" and the agreement between circumference derived diameter and balloon stretched diameter was examined. Forty consecutive patients who underwent closure of a single, without complex anatomy ASD were included. 3D and 2D TEE datasets were acquired and analyzed offline. Planimetry was used to calculate circumference derived diameter of ASD from 3D datasets. Patients were classified according to the presence of the "halo sign" and the agreement between circumference derived diameter and balloon stretched diameter was examined. Higher correlation and lower median absolute difference between 3D TEE measurements and 2D stretched balloon diameter was found in patients with "halo sign". In patients with the "halo sign" mean diameter difference was non-significant. On the contrary statistically significant difference was found in patients without the "halo sign". Significant difference was also found when comparing mean difference in the two patient groups. ASD sizing by 3D echocardiography, is accurate in patients with halo sign and it correlates well with the balloon sizing method. This study justifies further investigation concerning the reliability of 3D imaging for the selection of the ASD device size with a view to avoid balloon sizing, decrease procedural time and thus simplify the procedure.