title: Valve-in-valve hemodynamics of 20-mm transcatheter aortic valves in small bioprostheses.
abstract: BACKGROUND
  Transcatheter aortic valve (TAV) implantation is a treatment for selected patients with failing bioprostheses. We previously showed that currently available SAPIEN (Edwards Lifesciences, Irvine, CA) TAV sizes did not yield acceptable valve-in-valve (VIV) hemodynamics in small degenerated bioprostheses because optimal TAV function requires full stent expansion to its nominal size. The study objective was to determine (1) if 20-mm TAVs provide acceptable hemodynamics in small degenerated bioprostheses and (2) the effect of TAV spatial orientation on valvular hemodynamics and coronary flows.
  
  
  METHODS
  Twelve 20-mm TAVs were created for implantation within 19-mm and 21-mm degenerated Carpentier-Edwards Perimount (Edwards Lifesciences) and porcine bioprostheses. Degenerated valves were sutured into human homograft roots and mounted in a pulse duplicator. TAVs were implanted within bioprostheses as VIV in standard orientation, in which TAV and bioprosthetic commissures were aligned, and later with 60-degree rotation.
  
  
  RESULTS
  The 20-mm TAVs migrated retrograde into the left ventricle after VIV in the 21-mm Perimount bioprostheses. However, 20-mm TAVs in 19-mm Perimount (54.9±5.4 to 23.5±3.9 mm Hg, p=0.006) and 21-mm porcine bioprostheses (35.2±8.9 to 16.8±4.1 mm Hg, p=0.03) significantly reduced mean gradients. No significant reduction in pressure gradient occurred after VIV in 19-mm degenerated porcine bioprostheses. Mild regurgitation was observed after VIV. VIV with standard and 60-degree TAV orientation did not significantly alter hemodynamics or coronary flows.
  
  
  CONCLUSIONS
  Valve-in-valve hemodynamics with 20-mm TAV improved for 19-mm Perimount and 21-mm porcine but not 19-mm porcine bioprostheses. No significant differences in hemodynamics were noted by orientation with TAV and bioprosthesis commissural alignment or 60-degree rotation.
authors.affiliation: Department of Surgery, University of California at San Francisco Medical Center (UCSF) and San Francisco Veterans Affairs Medical Center (SFVAMC), San Francisco, California 94143-0118, USA.
authors.forename: Ali N
authors.initials: AN
authors.lastname: Azadani
authors.forename: Nicolas
authors.initials: N
authors.lastname: Jaussaud
authors.forename: Liang
authors.initials: L
authors.lastname: Ge
authors.forename: Sam
authors.initials: S
authors.lastname: Chitsaz
authors.forename: Timothy A M
authors.initials: TA
authors.lastname: Chuter
authors.forename: Elaine E
authors.initials: EE
authors.lastname: Tseng
mesh_terms: D001021:Aortic Valve / Q000601:surgery*; D001022:Aortic Valve Insufficiency / Q000503:physiopathology; D001024:Aortic Valve Stenosis / Q000601:surgery*; D001705:Bioprosthesis; D006328:Cardiac Catheterization / Q000379:methods*; D003326:Coronary Circulation / Q000502:physiology; D005548:Foreign-Body Migration / Q000503:physiopathology; D019918:Heart Valve Prosthesis Implantation / Q000379:methods*; D006352:Heart Ventricles; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008955:Models, Cardiovascular; D011183:Postoperative Complications / Q000503:physiopathology; D011474:Prosthesis Design; D011475:Prosthesis Failure; D017755:Prosthesis Fitting; D012086:Reoperation