Transcatheter closure of ostium secundum atrial septal defect (osASD) has been the first-line treatment in most children and adults since the 2000s. Some major adverse events (MAE), such as aortic erosion, have been infrequently reported.

To report early outcomes in different subgroups by age and investigate risk factors associated with MAE.

This prospective, single-centre, cohort study included 2253 consecutive patients referred for transcatheter osASD with Amplatzer Septal Occluder (ASO) (Abbott®) between May 1998 and December 2021. Peri-procedural data associated with MAE at 1 month were investigated.

Of 2253 patients, 1388 (61.6%) were adults and 865 (38.4%) were children, including 38 (1.7%) who weighed < 15 kg. Mean ± standard deviation osASD diameter was 18 ± 7 mm, 22.7% of patients had a deficient aortic rim and 0.9% had a deficient inferior vena cava rim. Procedural success was achieved in 98.1% (95% confidence interval [CI] 97.4–98.6%). A total of 32 peri-procedural MAE occurred in 31 patients (1.4%, 95% CI 0.9–−1.9%) including 19 device embolizations (0.8%) and two cardiac erosions (0.1%). No peri-procedural deaths were reported. There were no significant differences in the incidence of MAE between age and weight subgroups. In univariate analysis, MAE were significantly associated with atrial arrhythmia history before the intervention ( P = 0.013), inferior vena cava rim deficiency ( P < 0.001), antero-inferior rim deficiency ( P = 0.004), absence of balloon sizing ( P = 0.026), larger prosthesis size ( P = 0.017), maximal atrial septal defect size/body surface area ≥ 20 mm/m ² ( P = 0.008).

Transcatheter osASD closure using ASO has a high procedural success rate across a broad population of children and adults, reinforcing that transcatheter osASD closure is the intervention of choice for a wide range of patients and osASD morphologies.