title: Effect of transcatheter aortic valve size and position on valve-in-valve hemodynamics: An in vitro study.
abstract: Transcatheter heart valve implantation in failed aortic bioprostheses (valve-in-valve [ViV]) is an increasingly used therapeutic option for high-risk patients. However, high postprocedural gradients are a significant limitation of aortic ViV. Our objective was to evaluate Medtronic CoreValve Evolut R ViV hemodynamics in relation to the degree of device oversizing and depth of implantation.
  
  
  
  Evolut R devices of 23 and 26 mm were implanted within 21-, 23-, and 25-mm Hancock II bioprostheses. Small and gradual changes in implantation depth were attempted. Hemodynamic testing was performed in a pulse duplicator under ISO-5840 standard.
  
  
  
  A total of 47 bench-testing experiments were performed. The mean gradient of the 26-mm Evolut R in 23- and 25-mm Hancock II was lower than 23-mm Evolut R (P < .001). However, the mean gradient of 26-mm Evolut R in 21-mm Hancock II bioprostheses R (ranging from 21.30 ± 0.23 to 24.30 ± 0.22 mm Hg) was worse than 23-mm Evolut R (ranging from 15.94 ± 0.18 to 20.35 ± 0.16 mm Hg, P < .001). Furthermore, our results suggest that supra-annular implantation of 23-mm and 26-mm Evolut R devices within the bioprostheses can lead to lower gradient and improved leaflet coaptation. Regardless of implantation depth, superior transvalvular gradient is expected with 26-mm Evolut R than 23-mm Evolut R in a nonstenotic Hancock II with a true internal diameter > 17.5 mm.
  
  
  
  The current comprehensive bench-testing assessment demonstrates the importance of both transcatheter heart valve size and device position for the attainment of optimal hemodynamics during ViV procedures. Additional in vitro testing may be required to develop hemodynamics-based guidelines for device sizing in ViV procedures in degenerated surgical bioprostheses.
authors.affiliation: Department of Mechanical and Materials Engineering, University of Denver, Denver, Colo.
authors.forename: Ali N
authors.initials: AN
authors.lastname: Azadani
authors.affiliation: Houston Methodist DeBakey Heart and Vascular Center, The Houston Methodist Hospital, Houston, Tex.
authors.forename: Michael
authors.initials: M
authors.lastname: Reardon
authors.affiliation: Division of Cardiovascular Surgery, Escola Paulista de Medicina, Universidade Federal de Sao Paulo, Sao Paulo, Brazil.
authors.forename: Matheus
authors.initials: M
authors.lastname: Simonato
authors.affiliation: Division of Cardiothoracic Surgery, University of Washington, Seattle, Wash.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Aldea
authors.affiliation: Medizinische Klinik und Poliklinik II, Universitätsklinikum Bonn, Bonn, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Nickenig
authors.affiliation: Rabin Medical Center, Beilinson Campus, Petah Tikva, Israel.
authors.forename: Ran
authors.initials: R
authors.lastname: Kornowski
authors.affiliation: Division of Cardiology, University of Washington, Seattle, Wash. Electronic address: ddvir@uw.edu.
authors.forename: Danny
authors.initials: D
authors.lastname: Dvir
mesh_terms: D001021:Aortic Valve / Q000503:physiopathology / Q000601:surgery*; D001705:Bioprosthesis; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation*; D006439:Hemodynamics; D008422:Materials Testing; D011474:Prosthesis Design; D011475:Prosthesis Failure; D065467:Transcatheter Aortic Valve Replacement / Q000009:adverse effects / Q000295:instrumentation*
keywords: CoreValve Evolut R; in vitro testing; transcatheter heart valve replacement; valve-in-valve; valvular hemodynamics