Analysis of ASD parameters
The ASD parameters in this study including the maximum diameter, the minimum diameter, circular index (the ratio of the maximal to minimal diameters, ASD shape were distinguished by the circular index, round ASD defined as those patients with a circular index less than 1.4 and the oval shape defined as those with a circular index 1.4 or greater)13, and circumference. All the measurements taken on the 2D-TEE images and 3D-TEE images were in the same portion of the cardiac cycle when the size appeared largest, typically isovolumetric diastole, which is the same frame image for post-processing and 3D printing. As to the measurement of 2D-TEE images, the bi-atrial view, the aortic root short axis view and the apical four-chamber view were regarded as the standard echocardiographic measurement section,the defect was measured in each of these views and the maximum diameter and the minimum diameter was determined. For 3D-TEE measurements, the angle was carefully adjusted on the multiplanar reconstruction images to identify the largest plane, the longitudinal planes of the maximal and minimal ASD dimensions were identified using guidance on the en face image of the ASD, and the size parameters were measured on the longitudinal planes. When came to the 3D ASD models, the maximum diameter and the minimum diameter were measured by vernier caliper directly. A soft aluminum wire was used to shape the ASD, unfold the soft aluminum wire and the length measured by a vernier caliper was regarded as the circumference of ASD. All the measurements of ASD from the three methods were independently performed without knowing the results of others.