RESUMO
Objective To evaluate medium-term valvular functionality after transcatheter pulmonary valve replacement in sheep using a novel polymeric prosthetic pulmonary valve(PPHV). Methods In this study, we designed a novel polymeric trileaflet transcatheter pulmonary valve with a balloon-expandable stent, and the valve leaflet was made of 0. 1mm expanded polytetrafluoroethylene( ePTFE) . We chose bovine pericardium valve as control. Pulmonary valve stents were implanted in situ by right ventricular apical approach in 12 healthy sheep(10 for polymeric valve and 2 for bovine pericardium valve) weighing anaverageof(22.1±2.3)kg. Echocardiography,angiography,64-rowcomputedtomography(CT),andautopsywereusedto assess valvular function 12 weeks after implantation. Results Two PPHVs failed to be implanted in situ of pulmonary valve po-sition. Implantation was successful in the other 10 sheep. One sheep died of pneumonia, and the other 9 sheep survived at the end of follow-up. Echocardiography 12 weeks after implantation showed all the PPHVs exhibited good functionality and no sig-nificant insufficiency. The peak-peak transvalvular pressure gradient of the PPHVs was(28.2 ±8.0)mmHg(16-38 mmHg) (1 mmHg=0. 133 kPa), while that of two bovine pericardium valves were 16 and 21 mmHg. Angiography and CT 12 weeks after implantation demonstrated orthotopic position and normal operation of the valves,and no deformation of the valved stents. Pathological examination of the explanted PPHVs 12 weeks after implantation showed no degradation or damage of the ePTFE leaflets and most of the leaflets were thin and pliable, without significant thrombus or calcification, while visible pannus over-growth was found at the bottom of the valve leaflets, in the commissural areas and on the sealing cuff. Conclusion The medi-um-term effects of the novel ePTFE pulmonary valve after transcatheter pulmonary valve implantation in sheep is good. The no-vel PPHV exhibits good anti-adhesion, anti-degradation, anti-thrombus, anti-calcification performance and good biomechanical property. The hemodynamic parameter of PPHV is comparable to bovine pericardium valve. Optimizing the valve design might eliminate the problem about pannus overgrowth.