Transcatheter closure of ostium secundum atrial septal defect (osASD) has been the first-line treatment since the 2000s, with the Amplatzer Septal Occluder (ASO) being the most commonly used device. Device embolization is the most frequent major complication. This study aims to identify key echocardiographic predictors of device embolization in a large patient cohort.

This prospective, single-center cohort study included patients who underwent transcatheter osASD closure with ASO between 1998 and 2021 at Marie Lannelongue Hospital. Echocardiographic assessments included osASD size and rim evaluation. Rim deficiency was defined as <5mm. The osASD size-to-body surface area (BSA) ratio was calculated. Logistic regression models identified factors associated with embolization.

Among 1901 patients with complete echocardiographic data, 19 (1%) experienced device embolization within 48hours. Eleven occurred in adults and eight in patients under 18years old. Ten devices embolized within the right heart cavities or pulmonary trunk while nine migrated into the left cavities or aorta. Thirteen devices were successfully retrieved by catheterisation and in four cases osASD closure was successfully performed during a second attempt using a larger prosthesis. Embolization was significantly associated with larger osASD size (22±9mm vs. 18±7mm, p=0.031) and an osASD size/BSA ratio≥20mm/m² (OR 5.27 [1.95–14.22], p=0.001). IVC, antero-inferior, and postero-inferior rim deficiencies were also significant predictors (p<0.001, p<0.001, and p=0.023, respectively). The absence of balloon sizing increased embolization risk (p=0.002). In multivariate analysis, IVC rim deficiency (OR 15.38 [3.58–66.08], p<0.001) and an osASD size/BSA ratio≥20mm/m² (OR 4.27 [1.46–12.53], p=0.008) remained independent predictors.

Transcatheter osASD closure is highly successful with low major complication rates. However, device embolization is associated with IVC rim deficiency and an osASD size/BSA ratio≥20mm/m².