title: Minimally invasive off-pump valve-in-a-ring implantation: the atrial transcatheter approach for re-operative mitral valve replacement after failed repair.
abstract: OBJECTIVE
  Based upon recent developments in transcatheter technology, this study was designed to evaluate the feasibility and haemodynamic performance of transcatheter valve-in-a-ring (VinR) implantation for potentially failed mitral repair using a minimally invasive, transatrial, off-pump approach.
  
  
  METHODS
  Adult sheep (54.3+/-3.0 kg) underwent mitral valve repair with a 26 mm complete annuloplasty ring (Physio) using standard conventional techniques. To simulate the redo operation, a transcatheter 23 mm pericardial prosthesis (Edwards Sapien) mounted on a balloon-inflatable steel stent was deployed within the annuloplasty ring. VinR implantation was performed off-pump under rapid pacing in four and on-pump in three animals using an antegrade transatrial approach under fluoroscopic guidance.
  
  
  RESULTS
  Transcatheter VinR implantation was successful in all seven sheep. Mean transvalvular gradient was 4.9+/-0.3 mmHg. VinR function was excellent with no leak in one, good with mild leak in five (trans-stent: four, paravalvular: one) and sufficient with moderate central leak in one animal, respectively. Valve deployment required 10.0+/-0.7 min and all transcatheter prostheses were confirmed in good position on postmortem analysis, without any signs of valve dislocation or embolisation. In an in-vitro model, the minimum force required to dislodge the valve was 32.9+/-5.2N, which was well above the normal estimated forces generated by the left ventricle. One animal was kept alive to assess mid-term outcome and is still well 12 months after the VinR implantation.
  
  
  CONCLUSIONS
  Transatrial, transcatheter mitral VinR implantation is feasible using a minimally invasive off-pump approach. VinR implantation is a promising concept for re-operative surgery for selected patients after failed mitral valve repair.
authors.affiliation: Department of Cardiac Surgery, Heartcenter, University of Leipzig, Leipzig, Germany. kempfert@web.de
authors.forename: Joerg
authors.initials: J
authors.lastname: Kempfert
authors.forename: Johannes
authors.initials: J
authors.lastname: Blumenstein
authors.forename: Michael W A
authors.initials: MW
authors.lastname: Chu
authors.forename: Patrick
authors.initials: P
authors.lastname: Pritzwald-Stegmann
authors.forename: Tobias
authors.initials: T
authors.lastname: Kobilke
authors.forename: Volkmar
authors.initials: V
authors.lastname: Falk
authors.forename: Friedrich W
authors.initials: FW
authors.lastname: Mohr
authors.forename: Thomas
authors.initials: T
authors.lastname: Walther