title: Transcatheter pulmonary valve replacement by hybrid approach using a novel polymeric prosthetic heart valve: proof of concept in sheep.
abstract: BACKGROUND
  Since 2000, transcatheter pulmonary valve replacement has steadily advanced. However, the available prosthetic valves are restricted to bioprosthesis which have defects like poor durability. Polymeric heart valve is thought as a promising alternative to bioprosthesis. In this study, we introduced a novel polymeric transcatheter pulmonary valve and evaluated its feasibility and safety in sheep by a hybrid approach.
  
  
  METHODS
  We designed a novel polymeric trileaflet transcatheter pulmonary valve with a balloon-expandable stent, and the valve leaflets were made of 0.1-mm expanded polytetrafluoroethylene (ePTFE) coated with phosphorylcholine. We chose glutaraldehyde-treated bovine pericardium valves as control. Pulmonary valve stents were implanted in situ by a hybrid transapical approach in 10 healthy sheep (8 for polymeric valve and 2 for bovine pericardium valve), weighing an average of 22.5±2.0 kg. Angiography and cardiac catheter examination were performed after implantation to assess immediate valvular functionality. After 4-week follow-up, angiography, echocardiography, computed tomography, and cardiac catheter examination were used to assess early valvular function. One randomly selected sheep with polymeric valve was euthanized and the explanted valved stent was analyzed macroscopically and microscopically.
  
  
  RESULTS
  Implantation was successful in 9 sheep. Angiography at implantation showed all 9 prosthetic valves demonstrated orthotopic position and normal functionality. All 9 sheep survived at 4-week follow-up. Four-week follow-up revealed no evidence of valve stent dislocation or deformation and normal valvular and cardiac functionality. The cardiac catheter examination showed the peak-peak transvalvular pressure gradient of the polymeric valves was 11.9±5.0 mmHg, while that of two bovine pericardium valves were 11 and 17 mmHg. Gross morphology demonstrated good opening and closure characteristics. No thrombus or calcification was seen macroscopically.
  
  
  CONCLUSIONS
  This design of the novel ePTFE transcatheter pulmonary valve is safe and effective to deploy in sheep by hybrid approach, and the early valvular functionality is good.
authors.affiliation: Department of Cardiothoracic Surgery, Changhai Hospital, Second Military Medical University, Shanghai, China; Centre of Cardiovascular Surgery, Guangzhou General Hospital of Guangzhou Military Region, Guangzhou, China.
authors.forename: Ben
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Department of Cardiology, Changhai Hospital, Second Military Medical University, Shanghai, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Cardiothoracic Surgery, Changhai Hospital, Second Military Medical University, Shanghai, China.
authors.forename: Tong-yi
authors.initials: TY
authors.lastname: Xu
authors.affiliation: Department of Cardiology, Changhai Hospital, Second Military Medical University, Shanghai, China.
authors.forename: Zhi-gang
authors.initials: ZG
authors.lastname: Zhang
authors.affiliation: Department of Cardiothoracic Surgery, Changhai Hospital, Second Military Medical University, Shanghai, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Cardiothoracic Surgery, Changhai Hospital, Second Military Medical University, Shanghai, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Han
authors.affiliation: Department of Cardiothoracic Surgery, Changhai Hospital, Second Military Medical University, Shanghai, China.
authors.forename: Zhi-yun
authors.initials: ZY
authors.lastname: Xu
mesh_terms: D000818:Animals; D020099:Coated Materials, Biocompatible / Q000737:chemistry / Q000627:therapeutic use; D005240:Feasibility Studies; D006350:Heart Valve Prosthesis; D008297:Male; D008567:Membranes, Artificial; D023421:Models, Animal; D010767:Phosphorylcholine / Q000737:chemistry / Q000627:therapeutic use; D011108:Polymers / Q000737:chemistry; D011138:Polytetrafluoroethylene / Q000737:chemistry / Q000627:therapeutic use; D011474:Prosthesis Design; D011664:Pulmonary Valve / Q000601:surgery; D012756:Sheep; D065467:Transcatheter Aortic Valve Replacement / Q000295:instrumentation* / Q000379:methods*
chemical_list: D020099:Coated Materials, Biocompatible; D008567:Membranes, Artificial; D011108:Polymers; D010767:Phosphorylcholine; D011138:Polytetrafluoroethylene