The purpose of this study was to evaluate the safety and efficacy of the ASDOS-tech-nique (Sulzer-Osypka GmbH, Germany) for transcatheter closure of atrial septal defects within the oval fossa.

Although several attempts have been made to occlude defects within the oval fossa by transcatheter techniques, none of these has gained general acceptance.

Patients with a defect in the oval fossa measuring equal to or less than 20 mm diameter, with a residual septal rim of 5mm or greater, body weight greater than 10 kg, with clinical indications for surgical closure were considered for transcatheter closure. Follow-up investigations were performed at discharge, after 1, 3, 6 and 9 months, as well as after 1 and 2 years.

Of 78 patients considered for closure, a device was inserted in 41 patients (53%), with success being achieved in 40 patients (98%). The ages ranged from 1.1 to 15 years (7.8 ± 1.92 years), the ’stretched’ diameter of the defect from 10 to 20 mm (14.7 ± 2.60 mm), and the diameters of the inserted devices from 25 to 45 mm (33.2 ± 5.43 mm). Transient impairment of atrioventricular conduction occured in 4 patients. During the follow-up of 23.0 ± 5.6 months elective surgical closure of a residual shunt was performed 26 months after insertion of the devcie in one patient. None of the other patients required surgery, hospitalisation or medical treatment, and none is requiring further treatment of the defect within the oval fossa. Fracture of one arm of the device occurred in 4 patients, but the fractured arms are in an unchanged and stable position after a period of at least 19 months.

Our medium-term data show that transcatheter closure in children of defects within the oval fossa can be performed with a high efficacy and safety using the ASDOS-device.