Transcatheter closure of secundum atrial septal defect with atrial septal defect occlusion system (ASDOS): initial experience and short-term follow-up.

Transcatheter closure of secundum atrial septal defect is a well known alternative to surgery. It was attempted in seven patients (age range 7-34 years, mean 20.1 +/- 6.5 years) with the double umbrella nitinol device (ASDOS, Dr. Ing Osypka, Germany). The interatrial septal anatomy and blood flow were examined by transthoracic and multiplane transoesophageal echocardiography. The size of atrial septal defect varied from 1.25-2.4 cm (mean 1.75 +/- 0.3 cm), minimal septal rim 0.5-1.0 cm (mean 0.75 +/- 0.20 cm), and Qp/Qs 1.6-3.2:1 (mean 2.4 +/- 0.6). One patient had an atrial septal defect following surgery for left atrial myxoma. The procedure which involved the use of monorail system for deployment of device under transoesophageal echocardiography guidance, was successful in six (86%) of the seven patients. The size of the implanted device ranged from 30-45 mm. In two patients, the right atrial umbrella had to be oversized in comparison to the left atrial umbrella for stability and adequate occlusion of the defect. The patient in whom the procedure failed had a defect size of 1.7 cm, with minimal septal rim (anterosuperior) of 5 mm; however, the device could be easily retrieved. Immediately after and at follow-up of one year, transoesophageal echocardiography-guided colour flow mapping revealed complete abolition of left-to-right shunt in five (83%) of the six patients. One patient had a small residual flow at the posterior rim of the defect; none had atrioventricular valve regurgitation. Although the procedure is complex, it is safe with the advantage of excellent control on the monorail system for proper positioning, repositioning and, if required, retrieval of the device.