title: Tricuspid leaflet resection in an open beating heart for the creation of a canine tricuspid regurgitation model.
abstract: OBJECTIVE
  Outcomes of tricuspid valve replacement are poor, partly due to right heart remodelling. The research on its underlying mechanisms is hampered by a lack of animal models of tricuspid regurgitation (TR). Our objective was to create a reproducible and clinically compatible TR animal model to study right heart remodelling caused by TR.
  
  
  METHODS
  Fourteen juvenile male Beagle dogs were divided randomly into an intervention group (n = 11) and a sham-operated control group (n = 3). The intervention group underwent thoracotomy and right atrial incision following superior and inferior vena caval occlusion. The anterior leaflet, together with the chordae, of the tricuspid valve was resected in eight dogs ('one leaflet' group), whereas both anterior and posterior leaflets, together with the chordae, were resected in three dogs ('two leaflets' group). The right atrium and chest were then closed. The control group underwent the same procedure, except leaflet resection. One dog from the 'two leaflets' group and one control dog were sacrificed and autopsy was performed at 12 months post-surgery.
  
  
  RESULTS
  All dogs survived over the 1-year observation period postoperatively. TR grade IV occurred immediately postoperatively in the 'one leaflet' group, and TR grade IV plus in the 'two leaflets' group. The overall procedure lasted 30-40 min, and the mean time of vena caval occlusion was 87 ± 10 s. Central venous pressure increased from 6 ± 1.2 at baseline to 13 ± 1.7 mmHg (P < 0.01). By 12 months after TR creation, both in the 'one leaflet' group and in the 'two leaflets' group, the right atrial area, tricuspid annular diameter and right ventricular index of myocardial performance increased significantly, right ventricular fractional area change and tricuspid annular plane systolic excursion decreased significantly. Autopsy of the intervention dog revealed oedema, ascites and cirrhosis.
  
  
  CONCLUSIONS
  Our surgical technique to create a TR animal model was reproducible with high success and survival rates. This animal model would prove suitable to investigate the mechanisms of right heart remodelling.
authors.affiliation: Department of Cardiology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
authors.forename: Xu-jing
authors.initials: XJ
authors.lastname: Xie
authors.affiliation: Department of Cardiothoracic Surgery, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
authors.forename: Sheng-jie
authors.initials: SJ
authors.lastname: Liao
authors.affiliation: Department of Cardiac Surgery, Guangdong Provincial Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
authors.forename: Yue-heng
authors.initials: YH
authors.lastname: Wu
authors.affiliation: Department of Cardiac Surgery, Guangdong Provincial Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
authors.forename: Cong
authors.initials: C
authors.lastname: Lu
authors.affiliation: Department of Cardiac Surgery, Guangdong Provincial Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Zhu
authors.affiliation: Department of Ultrasound, Guangdong Provincial Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
authors.forename: Hong-wen
authors.initials: HW
authors.lastname: Fei
authors.affiliation: Department of Cardiac Surgery, Guangdong Provincial Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
authors.forename: Xue-jun
authors.initials: XJ
authors.lastname: Xiao
authors.affiliation: Department of Cardiac Surgery, Guangdong Provincial Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China 13829730611@163.com.
authors.forename: Huan-lei
authors.initials: HL
authors.lastname: Huang
mesh_terms: D000818:Animals; D006348:Cardiac Surgical Procedures / Q000379:methods*; D004195:Disease Models, Animal; D004285:Dogs; D008297:Male; D014261:Tricuspid Valve / Q000601:surgery*; D014262:Tricuspid Valve Insufficiency / Q000601:surgery*
keywords: Animal model; Right heart remodelling; Tricuspid regurgitation