title: [Chronic sheep modal for pulmonary valve implantation with domestic bileaflet mechanical prosthesis].
abstract: OBJECTIVE
  The aim of this study was to identify the long-term character of the domestic bileaflet mechanical valve in the chronic implanted sheep model and to evaluate the potential value of the modal.
  
  
  METHODS
  Six adult sheep underwent implanted mechanical bileaflet valve in pulmonary position under the cardio-pulmonary bypass with beating heart. The chronic implanted sheep model was built up and observed in the respects of a long-term survival, function of prosthesis and pathological specimen.
  
  
  RESULTS
  Six adult sheep survived with good condition after operation. The average survival period of six sheep was (221 +/- 208) days. Two sheep were postoperatively sacrificed in 41 and 71 days, respectively. The necropsy revealed normal valve function without thrombosis, periprosthetic leakage and overgrowth of fibrous tissue. One sheep died from dysfunction of prosthetic valve at the postoperative 196 days. The reason was the prosthetic thrombosis with slight overgrowth of fibrous tissue in periprosthesis. The other two sheep died from severe anemia at the postoperative 196 days and 234 days, and the autopsy revealed no abnormal finding else. And one remained to survive with good condition up to now (over 617 days) and was checked by Doppler echocardiogram twice at the postoperative 438 days and 479 days, respectively. The results showed normal function of the bileaflet valve in pulmonary position.
  
  
  CONCLUSIONS
  The long-term good effects would be achieved by using the implanted new domestic bileaflet valve in pulmonary position of sheep.
authors.affiliation: Department of Surgery, Fu Wai Hospital, Peking Unine Medical College, Chinese Academy of Medical Sciences, Beijing 100037, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Tang
authors.forename: Sheng-shou
authors.initials: SS
authors.lastname: Hu
authors.forename: Liang
authors.initials: L
authors.lastname: Meng
authors.forename: Jing
authors.initials: J
authors.lastname: Zhong
authors.forename: Yi-qian
authors.initials: YQ
authors.lastname: Dong
authors.forename: Yan-wen
authors.initials: YW
authors.lastname: Zhou
authors.forename: Wei-min
authors.initials: WM
authors.lastname: Yuan
mesh_terms: D000818:Animals; D019918:Heart Valve Prosthesis Implantation / Q000379:methods*; D008297:Male; D023421:Models, Animal; D011664:Pulmonary Valve / Q000601:surgery*; D012756:Sheep