title: Chronic aortic root pressure-loading assessment model.
abstract: OBJECTIVE
  Percutaneous placement of transcatheter prosthetic aortic valves without cardiopulmonary bypass (CPB) continues to gain clinical acceptance. However, information on pressure-loading characteristics of the aortic root/annular areas is limited. For this reason, we designed a preclinical model, implanting an aortic root load transducer with a power source/telemetry system for chronic, conscious, loading data acquisition. This research study was conducted to determine whether an animal model could accurately measure in vivo loading.
  
  
  METHODS
  Preoperatively, echocardiography and magnetic resonance imaging were used to determine both aortic annular and sinotubular junction dimensions, as well as ascending aortic length. Six adult sheep were placed on CPB, aortic root and ascending aorta were skeletonized and the origins of both coronary ostia were identified. Cardiac arrest with myocardial protection with cold coronary blood cardioplegia was instituted. A properly sized aortic root load-sensing device, consisting of a transcatheter aortic valve with a ring load transducer was implanted via a left apical ventriculotomy. Verification of position was determined before closure of the ventriculotomy. Each animal was weaned from CPB, and closed in routine fashion with the power source of the device placed in a subcutaneous pocket.
  
  
  RESULTS
  There were no operative deaths or significant postoperative complications. Serial pressure-load sensing assessments in a conscious state produced reproducible proprietary data.
  
  
  CONCLUSIONS
  This animal model allowed successful serial pressure-load sensing assessment of the aortic root/annular areas, providing a better physiological understanding of these anatomical inter-relationships. This added information could aid in future device designs with potential improved clinical outcomes.
authors.affiliation: Physiological Research Laboratories, Medtronic, Inc., Minneapolis, MN, USA.
authors.forename: Nancy
authors.initials: N
authors.lastname: Rakow
authors.affiliation: Physiological Research Laboratories, Medtronic, Inc., Minneapolis, MN, USA.
authors.forename: Noah
authors.initials: N
authors.lastname: Barka
authors.affiliation: Physiological Research Laboratories, Medtronic, Inc., Minneapolis, MN, USA.
authors.forename: Renee
authors.initials: R
authors.lastname: Gerhart
authors.affiliation: Physiological Research Laboratories, Medtronic, Inc., Minneapolis, MN, USA.
authors.forename: Erin
authors.initials: E
authors.lastname: Grassl
authors.affiliation: Physiological Research Laboratories, Medtronic, Inc., Minneapolis, MN, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Green
authors.affiliation: Physiological Research Laboratories, Medtronic, Inc., Minneapolis, MN, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Rothstein
authors.affiliation: Physiological Research Laboratories, Medtronic, Inc., Minneapolis, MN, USA.
authors.forename: Carl
authors.initials: C
authors.lastname: Schu
authors.affiliation: Physiological Research Laboratories, Medtronic, Inc., Minneapolis, MN, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Kopcak
authors.affiliation: Physiological Research Laboratories, Medtronic, Inc., Minneapolis, MN, USA.
authors.forename: Linda M
authors.initials: LM
authors.lastname: Shecterle
authors.affiliation: Physiological Research Laboratories, Medtronic, Inc., 11520 Yellow Pine Street NW, Minneapolis, MN 55448, USA congenital@aol.com.
authors.forename: John A
authors.initials: JA
authors.lastname: St Cyr
mesh_terms: D000818:Animals; D001011:Aorta / Q000503:physiopathology*; D001021:Aortic Valve / Q000601:surgery; D062186:Arterial Pressure / Q000502:physiology*; D000082882:Bicuspid Aortic Valve Disease; D004452:Echocardiography; D005260:Female; D006330:Heart Defects, Congenital / Q000601:surgery; D006349:Heart Valve Diseases / Q000601:surgery; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000379:methods*; D008279:Magnetic Resonance Imaging; D008297:Male; D023421:Models, Animal; D012756:Sheep
keywords: animal model; aortic root; assessment; chronic; pressure-loading