OBJECTIVETo study the clinical technology of transcatheter closure of secundum atrial septal defects (ASD) with Amplatzer device in younger and lower body weight children.

METHODSThe transcatheter closure of ASD using Amplatzer septal occluder (ASO) was performed in 165 children under 5 years of age (75 boys and 90 girls) with secundum ASD from Aug 1998 to May 2004. The age of the cases ranged from 2 to 5 (mean 3.7 +/- 1.1) years. The body weight ranged from 9 to 18 (mean 12.6 +/- 2.3) kg. The ratio of pulmonary circulation quantity to the systemic circulation quantity (Qp/Qs) was 3.2 +/- 1.9. All the patients underwent clinical examination, X-ray, electrocardiography (ECG) and echocardiography (Echo) for diagnosis of secundum ASD. The transthoracic echocardiography (TTE) was used to detect and measure the defect of the patients and even trans-esophageal echocardiography (TEE) had to be used when it was necessary. With Echo and X-ray guidance, the measuring balloon was used in the body and outside the body to determine the balloon-stretch diameters of ASD, and proper occluders were selected accordingly for the patients for interventional treatment of ASD.

RESULTSThe devices were implanted successfully in 163 (98.8%) cases. One failure occurred in a case in whom the device moved into the left atrium after release, and the other failure was that the position of the device was uncertain because of temporary unavailability of a special transducer for TEE. Surgical operations were performed for these two cases. The stretch diameter of ASD was from (8 - 30) mm, (mean 18.3 +/- 5.1) mm. The size of device was selected according to the stretch diameter of ASD. The diameter of the occluders selected was from (8 - 30), (mean 18.6 +/- 5) mm in this series. The occlusion procedure was monitored by fluoroscopy and TTE and in 5 cases (3%) by TEE. The diameter of right ventricle was improved within 2 days after occlusion from (mean 16.4 +/- 4.9) mm to (mean 12.6 +/- 3.8) mm, (p < 0.01). One hundred and forty seven cases belonged to the simple secundum ASD(89%). Thirteen cases who were complicated with other cardiac deformity were treated successfully with different interventional procedure. Six cases had multiple openings and three of these cases had tumour-like changes of the atrial septum which were closed completely just by one occluder. In only one case small quantity of residual shunt remains. No other severe complication was found in this group. About 100 cases (60%) had large ASD, so the procedure was more difficult in those cases.

CONCLUSIONThe clinical effectiveness of treatment of ASD in children under 5 years of age with Amplatzer occluders was satisfactory and therefore this therapeutic procedure is feasible for this age group of patients. Nevertheless, we do not recommend to use the technique for infants and children under 2 years of age. Strict selection of indications and proper size of occluder and good cardiologic and surgical settings are among the basic factors for successful interventional occlusion of ASD in young children.