title: Hemodynamics in the Valsalva sinuses after transcatheter aortic valve implantation (TAVI).
abstract: OBJECTIVE
  The study aim was to assess, in vitro, the hemodynamic modifications produced by transcatheter valves in the Valsalva sinuses, by mean of phase-resolved particle image velocimetry (PIV) measurements.
  
  
  METHODS
  Flow measurements were performed on a glass mock aortic root that included three polymeric valve leaflets, before and after the implantation of a Medtronic CoreValve device and of an Edwards SAPIEN valve. All experiments were carried out in a hydro-mechanical cardiovascular pulse duplicator system (Vivitro Superpump System SP3891) that reproduced physiologically equivalent pressures and flow rates conforming to the requirements of the standard ISO 5840:2005. The flow dynamics, before and after implantation of the two prosthetic devices, was characterized on the basis of phase-resolved velocity field and viscous shear rate measurements.
  
  
  RESULTS
  Direct comparison indicated that both transcatheter valves determined a significant variation of flow during the early stages of valve opening and during valve closure. In general, the presence of the two valve implants significantly reduced the flow activity in the Valsalva sinuses, promoting regions of stagnation at their base.
  
  
  CONCLUSIONS
  The reduction in flow in the Valsalva sinuses could be associated with the higher incidence of ischemic events reported after transcatheter heart valve implantation.
authors.affiliation: Department of Mechanical Engineering, University College London, London, UK.
authors.forename: Andrea
authors.initials: A
authors.lastname: Ducci
authors.affiliation: Department of Mechanical Engineering, University College London, London, UK.
authors.forename: Spyridon
authors.initials: S
authors.lastname: Tzamtzis
authors.affiliation: Department of Mechanical Engineering, University College London, London, UK.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Mullen
authors.affiliation: Department of Mechanical Engineering, University College London, London, UK.
authors.forename: Gaetano
authors.initials: G
authors.lastname: Burriesci
mesh_terms: D001021:Aortic Valve / Q000601:surgery*; D001783:Blood Flow Velocity / Q000502:physiology*; D006328:Cardiac Catheterization; D006349:Heart Valve Diseases / Q000503:physiopathology / Q000601:surgery*; D006350:Heart Valve Prosthesis; D006801:Humans; D008955:Models, Cardiovascular; D011474:Prosthesis Design; D012850:Sinus of Valsalva / Q000503:physiopathology*