Predictors of Successful Transcatheter Closure of Atrial Septal Defect by Cardiac Magnetic Resonance Imaging

The location, size, and rim of an atrial septal defect (ASD) are major determining factors for transcatheter closure. We compared the measurements of ASD size and the characteristics of atrial septal rim using cardiac magnetic resonance imaging (MRI) with those obtained using transesophageal echocardiography (TEE). Patients with an ASD that met established criteria were selected for evaluation by cardiac MRI and TEE. There were 66 patients who underwent both TEE and cardiac MRI. Bland-Altman comparative analysis was performed to demonstrate agreement between measurement of ASD by MRI and balloon sizing compared to measurement of ASD by TEE and balloon sizing. Twelve patients were excluded from transcatheter closure of ASD. TEE did not demonstrate an adequate measurement of the posterior inferior rim in 10 of 66 patients. Fifty-four patients underwent transcatheter closure using the Amplatzer septal occluder. Of these, 52 patients had successful closure (ASD measurements of 25.9 ± 5.6 mm using MRI and 21.9 ± 5.8 mm using TEE). The median device size was 28 mm (range, 11-38). Patients who had successful closure had a significantly smaller major axis of ASD and larger posterior inferior rim compared to those of patients who were excluded from the closure procedure. Cardiac MRI showed a better correlation of ASD diameter measurement to balloon sizing compared to TEE. We believe that the most important predictive factor for successful transcatheter closure of an ASD is an adequate posterior inferior rim, which is best visualized using cardiac MRI.