The aim. To assess the effectiveness and safety of transcatheter closure of a secondary atrial septal defect (ASD) using an occluder in symptomatic children weighing ≤10 kg. Materials and methods. In the period from November 2014 to June 2021, on the basis of the National Amosov Institute of Cardiovascular Surgery of the National Academy of Medical Sciences of Ukraine, closure of secondary ASD using an occluder was performed in 18 patients, among them 13 women (72.2%) and 5 men (27.8%). Th e mean age of the patients was 18.94±9.44 months (the youngest patient was 12 months, the oldest was 4 years). The mean weight was 9.294±1.170 kg (6.4 kg to 10 kg), the mean Z-score was -1.7±1.5 (-4.6 to 0.46), the mean height was 80 cm (71 cm to 88 cm). According to the measurements by transesophageal echocardiography (TEE), the average size of the defects was 13.7 mm±3.6mm (the largest 18.0 mm, the smallest 6.0 mm). Results and discussion. In our publication, the effectiveness of the method was 100% (18/18), while the world statistics show 94-95%. Th e frequency of complications was 5.6% (n=1). We suggest that this is associated with the use of a sizing balloon and careful selection of the device. When choosing treatment tactics for symptomatic children weighing ≤10 kg, the decisive factor was the determination of the presence of edges and the size of the defect. Defects were considered suitable for closure, according to TEE data, when all margins of the defect were ≥4 mm, except for the aortic margin. Although the total length of the interatrial membrane was taken into account, it was not of decisive importance, since for most occluders with the presence of all edges, the fields of the implant could not interfere with the work of the anatomical structures of the heart. To determine the real size of the defect, we recommend a measuring balloon under TEE control. The following devices were used to close the defect: MemoPart ASD occluder, Amplatzer Septal Occluder, LifeTech HeartR Occluder, LifeTech HeartR Multi-Fenestrated Atrial Septal Defect (MF-ASD) Occluder.   Conclusion. After the study, we are convinced that the endovascular method of closing a hemodynamically significant secondary ASD for the treatment of children with a body weight of ≤10 kg has proven to be an effective method, with successful implantation of the occluder in 100% of cases.

According to European guidelines, endovascular closure is the method of choice for defects with favorable anatomy. However, there are no clear criteria for determining favorable anatomy and this issue requires additional investigation. According to literature data, only 24.2% of secundum atrial septal defects (ASDII) have a central location, others have complicated anatomy. The aim. To analyze the experience of endovascular closure of ASDII with complex anatomy. Materials. In the period from 2003 to 2021, 1732 transesophageal echocardiographies and intracardiac echocardiographieswereperformedinpatientswithASDIIinitiallydiagnosedaccordingtotransthoracicechocardiography, and only 1408 (91.8%) were selected for endovascular closure. Mean age was 19.9±18 years, mean weight was 45±26.68 kg. Methods. The standard closure technique was primarily used in 100% of cases, and only when it was ineffective, we used modified techniques. Results. Modified techniques were used in 478 (33.9%) of 1408 patients and were effective in 460 (96.2%) patients with the complex anatomy. Based on previous statement, 460 (32.6%) of 1408 patients (one third of all) had modified techniques utilized and avoided open surgery. In 18 (1.3%) cases, it was impossible to close the defect. The overall technical success of transcatheter closure was 98.7% (1390 patients). Nineteen (1.3%) patients with poor visualization of inferior rim on transesophageal echocardiography had intracardiac echocardiography; in two of them inferior rim was present, others had open surgery. The rate of complications in immediate periprocedural period was 1.9% (27 patients). One death was recorded in the period of introduction of percutaneous interventions in our institution. Mean follow-up period was 5.41±3.28 years. In the follow-up period two complications were observed: 1 case of erosion, 17 (1.9%) cases of new-onset atrial fibrillation. Conclusion. The majority (90.6%) of ASDII can be closed percutaneously. Modified techniques improve the efficacy of the procedure enabling to close 32.6% of the defects. Safe procedure for the defects with complex anatomy is possible only with surgical and arrhythmological services back-up.