title: Direct-access valve replacement a novel approach for off-pump valve implantation using valved stents.
abstract: OBJECTIVE
  This study validates the off-pump antegrade transventricular route for ultrasound-guided direct-access aortic valved stent implantation.
  
  
  BACKGROUND
  Direct-access aortic valved stent implantation offers numerous advantages over the remote-access percutaneous approach and may one day provide an alternative to surgical aortic valve replacement.
  
  
  METHODS
  Valved stents were implanted off-pump in 12 pigs (68.5.0 +/- 7.3 kg) via direct-access transapical approach using a left-sided mini-thoracotomy and continuous ultrasonic and fluoroscopic guidance. Acute valved stent function was studied with intravascular and intracardiac ultrasound. All valved stents were tested in vitro before insertion. Macroscopic analysis was performed at necropsy.
  
  
  RESULTS
  In 8 of 12 pigs, valved stents were delivered to the target site over the native aortic valve leaflets without interference of coronary blood flow and with good acute valve function. Two valved stents were deployed and supra-annularly occluded the coronary orifice, leading to fatal outcome. Two valved stents dislodged into the left ventricle, one because of size mismatch and one that failed to unfold correctly.
  
  
  CONCLUSIONS
  Twelve pigs underwent deployment of a valved stent in the aortic position. Six valves observed for an average 4.5-h period showed satisfactory postimplantation valve function.
authors: Division of Cardiac Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors: Christoph H
authors: CH
authors: Huber
authors: Lawrence H
authors: LH
authors: Cohn
authors: Ludwig K
authors: LK
authors: von Segesser
mesh_terms: D000818:Animals; D001021:Aortic Valve; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000295:instrumentation / Q000379:methods; D015607:Stents; D013552:Swine; D013908:Thoracotomy / Q000379:methods