Abstract: AIM:To investigate the effectiveness of intravenous recombinant human brain natriuretic peptide(rhBNP) on pulmonary hypertension(PH) in patients undergoing transcatheter closure of atrial septal defect(ASD).METHODS:Fifty-six cases of ASD with PH were treated with transcatheter closure and patients were randomly divided into treatment group(30 patients) and control group(26 patients).Patients in the treatment group were given rhBNP i.v.after closure of patent ductus arteriosus,and changes of pulmonary artery pressure,endothelin(ET) and 6-min walking distance(6MWD) were tested and compared between groups 48 h and 6 months after treatment.RESULTS: Results were similar in the two groups 48 h and 6 months after treatment.Postoperative levels of pulmonary artery pressure and postoperative ET were significantly lower than preoperative levels(P<0.05) and 6MWD increased significantly(P<0.05).However,levels of pulmonary artery pressure and ET of the treatment group were significantly lower than those of the control groups after i.v.administration of recombinant brain natriuretic peptide(P<0.01).6MWD significantly increased compared with that of the control group(P<0.01).CONCLUSION:rhBNP further reduces pulmonary artery pressure and improves cardiac function in patients with PH after transcatheter closure of ASD.