Objective: To observe the efficacy and safety of low-molecular-weight heparin (LMWH) in the treatment of children after transcatheter closure of atrial septal defects (ASD).
Methods: 48 patients were randomized into unfractionated heparin (UFH) group or LMWH group. 20mg LMWH (enoxaparin sodium) was administered twice through subcutaneous injection in abdominal wall after occlusion. But in the control group UFH (10 IU /Kg/h) was intravenously given for 24 hours after occlusion. Aspirin therapy, which began right after the occlusion of ASD, lasted for 6 months in all the patients. Activated partial thromboplastin time (APTT) were determined before the occlusion of ASD, at 6h, 24h and 48h after device implantation. Transthoracic echocardiograph(TTE) were performed 1, 3, and 6 months after the occlusion of ASD.
Results: The follow-up has been performed on 43 patients (LMWH 22, UFH 21). Neither thrombus on ASD occluders nor severe hemorrhage complications were found during the follow-up period. Before occlusion no significant difference in APTT was noted in the two groups. But after occlusion APTT of the UFH group was significantly prolonged at 6h and 24h but returned to normal range at 48h. However, such significant changes were not found in the LMWH group. Inter-group comparison revealed that APTT was more significantly prolonged in UFH group at 6h and 24h but no significant inter-group differences were found at 48h.
Conclusions Enoxaparin sodium is safe, effective and convenient in the treatment of children after transcatheter closure of ASD.

Key words: Low-molecular-weight Heparin Children Atrial septal defect Occlusion