Balloon Occlusive Diameter of Non-Circular Atrial Septal Defects in Transcatheter Closure with Amplatzer Septal Occluder

Background and Objectives: The aim of this study was to investigate the balloon occlusive diameter (BOD) of non-circular defects in the transcatheter closure of atrial septal defect (ASD). Subjects and Methods: A total of 67 patients who had undergone transcatheter closure of an ASD were reviewed retrospectively. A noncircular defect was defined as the ratio of the short diameter to the long diameter of the defect on the en-face image less than 0.75. The BOD was compared with the long diameter of the defect and then compared between the two groups. Results: There were 22 patients with circular defects and 45 patients with non-circular defects. The difference in BOD measuring from the long diameter of the defect was quite different between the two groups and significantly smaller in non-circular morphology ($0.1{\pm}4.0$ vs. $2.3{\pm}2.1$, p=0.006). The difference in BOD measurement from the long diameter of ASD showed a positive correlation with the ratio of the short diameter to the long diameter of ASD (b/a) ($r^2$=0.102, p=0.008). In the non-circular morphology of ASD, the difference in BOD measured from the long diameter had a significant negative correlation with the long diameter of ASD ($r^2$=0.230, p=0.001), whereas in circular ASD, no significant correlation was found between the difference in BOD and the long diameter of ASD (p=0.201). Conclusion: The BOD compared with the long diameter measured from three-dimensional transesophageal echocardiography was smaller in non-circular ASD than in circular ASD. This difference was much smaller in non-circular ASD with a large long diameter.