Objective To observe the availability and safety of ventricular septal defect (VSD) occluder in infants and young children with large patent ductus arteriosus (PDA) associated with severe pulmonary hypertension.Methods Five patients (1 male and 4 fomale) of large PDA aged 5 months to 3 years,weighted from 5.1 to 15 kg,body surface area (BSA) 0.37-0.58 m2 underwent transcathter intervention with concentric VSD occluders from June 2008 to May 2009.Arterial ducta were tube-like and their diameters were 5.7 to 8.5 mm,with ulmonary vascular resistance from 4.8 to 5.7 Wood Unit,Qp/Qs 3.4-4.6.Three patients were given Bosentan after intervention.Results The large PDAs were successfully closed with VSD occluders,including 1 concentric perimembranous VSD occluder and 4 muscular VSD occluders.They all discharged 4 to 5 days with hidrosis and weight improved.Echocardiogram indicated VSD occluder was stable,no residue shunt and no stricture of left pulmonary artery and descending aorta were found.According to tricuspid and pulmonary regurgitation,pulmonary arterial pressure decreased differently and returned to normal after 6 months follow-up.Conclusion VSD occluder is available and effective to close large PDA associated with severe pulmonary hypertension in inrants and young children,but more cases and long-term follow-up are necessary.