OBJECTIVEThis study was undertaken to investigate the indication, methodology and complication of transcatheter closure of secundum atrial septal defect (ASD). ASD transcatheter occlusion techniques have become alternative to surgical procedures. A number of different devices are available for transcatheter ASD closure. The type and incidence of complications depend partially upon different devices.

METHODSA retrospective analysis was performed on the patients treated from October 1998 to January 2003. Transcatheter closure of ASD with Amplatzer septal occluder (ASO) was performed in 119 patients, of whom 3 patients were multiple ASD, 3 associated with pulmonary stenosis (PS) and 3 patent ductus arteriosus (PDA). The age of the cases ranged from 0.8 to 17 years (mean 7.5 +/- 2.8 years) and the body weight ranged from 6.7 to 88 kg (mean 23.7 +/- 7.8 kg). They all met with criteria for transcatheter closure. The balloon-stretched diameter of ASD was determined with fluoroscopy, ultrasound and measuring plate. A choice of device size was identical to or 1 approximately 2 mm larger than the stretched diameter (SD). A simultaneous PDA closure with device or balloon dilation was done in six cases associated with PDA or PS, respectively. Follow-up was performed based on the echocardiographic and clinical findings.

RESULTSIn 119 cases examined with transesophageal echocardiography (TEE) or trans-thoracic echocardiography (TTE), ASD mean diameter was (12.9 +/- 5.6) mm (6.5 - 34.5 mm), pulmonary mean pressure was (29.0 +/- 5.0) mmHg (25.0 - 62.0 mmHg), and SD was (15.7 +/- 4.8) mm (8.0 - 38.0 mm). The diameters of these devices were (15.0 +/- 5.0) mm (8 - 38 mm). The devices were successfully implanted in 112 cases. Of them, 3 patients had multiple ASD with one device occlusion. 6 cases associated with PDA or PS were treated successfully with PDA occlusion or balloon dilatation, respectively. The immediate, one month and one year complete occlusion rates were 93.8% (105/112), 97.3% (109/112) and 98.2% (110/112), respectively. Residual shunt remained in 2 cases. No complication occurred except transient atrial premature beats and grade II type 1 A-V block in 5 cases (4.5%) and 1 cases (0.9%), respectively. The whole time period of the procedure ranged from 25 to 68 minutes. The total follow up period was from one month to 4.3 years. No unsatisfactory device position or embolization or clinical evidence of bacterial arteritis was found during the follow-up period.

CONCLUSIONTranscatheter closure of secundum ASD using the ASO is a safe and effective alternative to surgical repair. Transcatheter closure of secundum ASD associated with small anterior, inferior or posterior rim is feasible using ASO. ASO can be performed in infants and young children only if the diameter of disk is smaller than the diameter of atrial septum. Multiple ASD is not the contraindication for intervention. If the diameter of ASD is over 36 mm, the device choice should depend on the maximum diameter of ASD determined with echocardiography. TTE is suitable for the smaller ASD and TEE for the bigger ASD. It is very important to avoid air embolism and atrial perforation during the procedure.