ABSTRACT
Objective The purpose of this study was to investigate the preparation of a pulmonary self-expanding valved stent and the percutaneous implantation of a valved stent in the pulmonary valve position without cardiopulmonary bypass.Methods A bovine jugular valve conduit was trimmed to remove the extraneous materials to reduce profile,and then was sutured onto nitinol stents to form a pulmonary self-expanding valved stent.In vitro,it was tested by a pulsatile mock loop system.Through a 24F delivery system,the valved stents were deployed in the pulmonary valve position of 8 pigs,and then in vivo assessment with echocardiography and a postmortem examination were carried out.Results The pulmonary self-expanding valved stent has an inner diameter of (21.9 ± 1.6) mm,an outer diameter of (24.6 ± 1.5 ) mm,a length of (27.9 ± 4.3 )mm,and an effective orifice area of ( 1.8 ±0.2) cm2.7 of the 8 valved stents were exactly deployed in the native pulmonary valve position,1 valved stent failed.The transvalvular pressure gradient was (7.9 ± 3.3 ) mm Hg by catheter measurement,(9.3 ±4.1 ) mm Hg by Doppler echocardiography.The angiography showed no migration,no regurgitation and no paravalvular leak.The echocartiography showed all the new valves opened and closed well with 2 cases of mild regurgitation.Postmortem examination confirmed the valved stent straddled the pulmonary annuli without migration,the native valve was locked between the stent and arterial wall.Conclusion The acute study demonstrates that the self-expanding valved stent can be successfully implanted in the pulmonary position by a catheter delivery system and function well.Percutaneous pulmonary valve implantation without cardiopulmonary bypass is feasible and has a wide clinical perspective.