title: Off-pump positioning of a conventional aortic valve prosthesis through the left ventricular apex with the universal cardiac introducer under sole ultrasound guidance, in the pig.
abstract: OBJECTIVE
  : To test an alternative to catheter and open-heart techniques, by documenting the feasibility of implanting an unmodified mechanical aortic valve (AoV) in the off pump, beating heart using the universal cardiac introducer (UCI) attached to the left ventricular (LV) apex.
  
  
  METHODS
  : In six pigs, the LV apex was exposed by a median sternotomy. The UCI was attached to the apex. A 12-mm punching tool (punch), introduced through the UCI, was used to create a cylindrical opening through the apex. Then, the AoV, secured to a holder, was introduced into the LV, using transesophageal echocardiographic, guided through the apical LV opening, navigated into the LV outflow tract, and positioned within the aortic annulus. Transesophageal echocardiographic guidance was useful for navigation and positioning by superimposing the aortic annulus and prosthetic ring while Doppler imaging verified preserved prosthetic function and absence of perivalvular leaks. The valve function and hemodynamics were observed before termination for macroscopic evaluation.
  
  
  RESULTS
  : The punch produced a clean opening without fragmentation or myocardial embolization. During advancement of the mechanical AoV, there were no arrhythmias, mitral valve dysfunctions, evidence of myocardial ischemia, or hemodynamic instability. The AoVs were well seated over the annulus, without obstructing the coronaries or contact with the conduction system. The ring of AoVs was well circumscribed by the aortic annulus.
  
  
  CONCLUSIONS
  : This study documented the feasibility of positioning a mechanical AoV on the closed, beating heart. These results should encourage the development of adjunct technologies to deliver current tissue or mechanical AoV with minimal side effects.
authors.affiliation: From the *Canadian Surgical Technologies and Advance Robotics, Lawson Health Research Institute, London, Ontario, Canada; †Imaging Group, Robarts Research Institute, London, Ontario, Canada; and Departments of ‡Physiology and Pharmacology, §Medicine, ¶Anaesthesia, and ∥Medical Biophysics, the University of Western Ontario, and the London Health Science Center, London, Ontario, Canada.
authors.forename: Gerard M
authors.initials: GM
authors.lastname: Guiraudon
authors.forename: Douglas L
authors.initials: DL
authors.lastname: Jones
authors.forename: Daniel
authors.initials: D
authors.lastname: Bainbridge
authors.forename: Terence M
authors.initials: TM
authors.lastname: Peters