Objective: The purpose of this study was to compare transthoracic echocardiography (TTE), cardiac CT, and transesophageal echocardiography (TEE) in the evaluation of secundum atrial septal defect (ASD) for closure with an Amplatzer septal occluder in pediatric patients.
Subjects and methods: The cases of 28 children with ASD initially diagnosed with TTE who were scheduled for cardiac CT for evaluation for insertion of an Amplatzer septal occluder under TEE guidance were reviewed. The patients were divided into a group with small ASD (long axis < 1.5 cm) and a group with large ASD (long axis > or = 1.5 cm). Measurements of the ASD obtained at TTE, cardiac CT, and TEE were compared. Kappa statistics were used to correlate the diagnostic value of cardiac CT assessed by two independent reviewers.
Results: After cardiac CT, six patients were excluded from occluder implantation; therefore, 22 patients (seven boys, 15 girls; mean age, 4.95 years; range, 2-11 years) were included in the study. There were no significant differences in the ages and sexes of the patients in the two groups, but pulmonary-to-systemic blood flow ratio in the large-ASD group was significantly greater than that in the small-ASD group (3.54 +/- 1.43 vs 1.89 +/- 0.36; p = 0.001). With respect to long- and short-axis lengths of the ASD, interatrial septum, and four rims and to detection of rim deficiency, neither group had a significant difference between cardiac CT findings at ventricular end-systole and TEE findings. The long axis of the ASD in the large-ASD group measured at cardiac CT at end-systole and TEE was significantly longer than the long axis measured at TTE (p = 0.012). A high diagnostic score with good interobserver correlation (kappa = 0.674-0.750) validated the feasibility of cardiac CT in the assessment of ASD for closure with an Amplatzer septal occluder.
Conclusion: The long axis of a large ASD can be underestimated at TTE. Cardiac CT seems comparable with TEE in the assessment of ASD and is helpful in noninvasive evaluation for Amplatzer septal occluder implantation, especially for large ASD.