Objective To evaluate the feasibility and the immediate and mid-term therapeutic effect of transcatheter closure of patent ductus arteriosus ( PDA ) associated with severe pulmonary arterial hypertension ( SPAH) in adults． Methods Twenty-four adult PDA patients associated with SPAH ( 4 male，20 female， aged 19 to 45 years old［27． 8 ± 8． 1］) underwent attempted transcatheter closure of PDA from January 2002 to February 2011 in our hospital． Based on haemodynamic and clinical data before and after trial occlusion，the final duct occlusion was determined and carried out． Electrocardiograms and echocardiograms were used for follow-up evaluation after successful closure． Ｒesults Of 24 patients，23 had successful occlusion，and 1 failed． For patients with successful occlusion after trial occlusion，both systolic pulmonary arterial pressure and mean pulmonary arterial pressures decreased markedly ［( 54． 87 ± 19． 24) mmHg vs ( 96． 09 ± 23． 08) mmHg ，P ＜ 0． 05，( 39． 17 ± 14． 81) mmHg vs ( 72． 87 ± 15． 77) mmHg，P ＜ 0． 05，respectively］， the dimensions of the left atrium，left ventricle，and pulmonary artery increased considerably during the follow up of 1 to 52 months ( averaging 11． 5 months) ． As for the patient with failed occlusion，pulmonary arterial pressures increased after trial occlusion，but aortic pressure decreased obviously，complicated with bradycardia and obnubilation; but after withdrawing the PDA occluder，the aortic pressure increased，meanwhile the heart rate and the consciousness recovered; occlusion was tried and failed for the second time before giving up． Conclusions Transcatheter closure is a safe and effective treatment for adults with PDA associated with reversible SPAH with excellent immediate and mid-term results，but further research is still needed for the evaluation of long-term results．

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