title: Valve-in-valve implantation using a novel supravalvular transcatheter aortic valve: proof of concept.
abstract: BACKGROUND
  Transcatheter valve implantation within degenerated bioprostheses is a potentially promising treatment for high-risk surgical patients. Clinical experience is limited; however, we have shown in vitro that currently available transcatheter aortic valve sizes did not provide acceptable hemodynamics in small bioprostheses. The objective of this study was to develop a new transcatheter valve that would provide good hemodynamics within degenerated bioprostheses.
  
  
  METHODS
  Supravalvular transcatheter valves were created using a Dacron covered stainless steel stent at the base and trileaflet pericardial leaflets in an open stent above the bioprosthesis. The transcatheter valves were implanted within 19-, 21-, and 23-mm Carpentier-Edwards Perimount bioprostheses with simulated degeneration using BioGlue to achieve a mean pressure gradient of 50 mm Hg. Hemodynamics of valve-in-valve implantation were studied in a pulse duplicator.
  
  
  RESULTS
  Supravalvular transcatheter valves successfully relieved bioprosthetic stenosis. Acceptable hemodynamics were achieved with a significant reduction in mean pressure gradient of 54.0 +/- 3.5 to 9.2 +/- 6.3 mm Hg in 23-mm bioprostheses (p < 0.001), from 49.3 +/- 3.1 to 14.4 +/- 4.7 mmHg (p < 0.001) in 21 mm, and from 53.9 +/- 3.8 to 28.3 +/- 9.8 mm Hg (p = 0.013) in 19-mm bioprostheses. Effective orifice area after valve-in-valve implantation increased significantly and was comparable to rereplacement with the same size bioprosthesis.
  
  
  CONCLUSIONS
  Valve-in-valve implantation was performed using a novel supravalvular transcatheter valve, which successfully relieved bioprosthetic stenosis. The hemodynamics were comparable with standard surgical valve replacement. Further studies are required to assess device safety and efficacy in patients.
authors.affiliation: Department of Surgery, University of California at San Francisco Medical Center, San Francisco, California 94143, USA.
authors.forename: Ali N
authors.initials: AN
authors.lastname: Azadani
authors.forename: Nicolas
authors.initials: N
authors.lastname: Jaussaud
authors.forename: Peter B
authors.initials: PB
authors.lastname: Matthews
authors.forename: Liang
authors.initials: L
authors.lastname: Ge
authors.forename: T Sloane
authors.initials: TS
authors.lastname: Guy
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; D001705:Bioprosthesis; D006328:Cardiac Catheterization / Q000379:methods*; D006349:Heart Valve Diseases / Q000503:physiopathology / Q000601:surgery*; D019918:Heart Valve Prosthesis Implantation / Q000379:methods*; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008954:Models, Biological; D011474:Prosthesis Design; D016896:Treatment Outcome