Transcatheter Closure of Complex Atrial Septal Defects in Children: A Single-Center Experience.

Objective: Although transcatheter atrial septal defect (ASD) closure has become the preferred treatment for ostium secundum ASD, closure of complex defects-characterized by large size, rim deficiencies, multiple fenestrations, aneurysmal or malaligned septum, or low body weight-remains technically challenging. This study evaluated the efficacy of transcatheter closure in children with complex ASDs. Materials and Methods: This retrospective single-center study included 15 patients aged 0-18 years who underwent transcatheter ASD closure between 2023 and 2025. All procedures were performed using the Occlutech Figulla Flex II ASD occluder and were guided by transthoracic and transesophageal echocardiography. Procedural data, complications, and follow-up outcomes were recorded. Results: The mean age was 7.0±4.4 years, and 60% of the patients weighed ≤15 kg. Complete occlusion was achieved in all children. Two patients (13.3%) experienced transient complications-one device embolization and one case of atrial premature beats-which resolved without permanent sequelae. No mortality or residual shunts were observed at 6-month follow-up. Conclusion: Transcatheter closure of complex ASDs is safe when performed by experienced operators who conduct careful anatomical assessments and select appropriate devices. Alternative implantation techniques may enhance procedural success in challenging anatomical conditions. Transcatheter closure is a reliable, minimally invasive alternative for complex ASD cases.