title: Diastolic properties of the Sorin Solo, ATS 3F, Edwards Prima Plus and Medtronic Freestyle stentless valves: an independent in-vitro comparison.
abstract: OBJECTIVE
  Currently, little is known of the diastolic properties of stentless valves that affect stress and strain on leaflets and, hence, their durability. In a pressurized aortic root model, a series of in-vitro tests was conducted to determine how stentless valves behave in diastole, and how they adapt to different annulus-to-sinotubular junction (STJ) ratios.
  
  
  METHODS
  Sixteen 25 mm stentless aortic valves (four each of the Sorin Solo, ATS 3F, Edwards Prima Plus and Medtronic FreeStyle) were sutured into a 32 mm Valsalva graft, suspending the commissures into the expandable region (42 mm). The neoaortic root was pressurized and the size of the STJ progressively reduced by wrapping the neocommissural ridge with Dacron rings. Endoscopic views and ultrasound imaging were used to observe the geometry of the leaflets, regurgitation, and the height and level of leaflet coaptation at different annulus-to-STJ ratios.
  
  
  RESULTS
  Pericardial prostheses built to mimic a cylinder (ATS 3F and Sorin Solo) showed the greatest tolerance to STJ dilatation and a larger coaptation surface, but also a tendency to roll in on themselves in an italic S-shape if oversized. Valves built to mimic native aortic leaflets (porcine Prima Plus and Medtronic Freestyle) showed a reduced tolerance to STJ dilatation, resulting in regurgitation and a smaller coaptation surface, but also a reduced tendency to roll if oversized.
  
  
  CONCLUSIONS
  Despite similar systolic performances, stentless prostheses behave differently during diastole. The 3F and Solo valves benefit from a better tolerance to STJ dilatation, while the Prima Plus and Freestyle benefit from a more stable shape of closure under conditions of oversizing.
authors.affiliation: Cardiac Surgery Department, European Hospital, Rome, Italy. lweltert@gmail.com
authors.forename: Luca
authors.initials: L
authors.lastname: Weltert
authors.forename: Saverio
authors.initials: S
authors.lastname: Nardella
authors.forename: Fabiana
authors.initials: F
authors.lastname: Girola
authors.forename: Raffaele
authors.initials: R
authors.lastname: Scaffa
authors.forename: Alessandro
authors.initials: A
authors.lastname: Bellisario
authors.forename: Daniele
authors.initials: D
authors.lastname: Maselli
authors.forename: Ruggero
authors.initials: R
authors.lastname: De Paulis
mesh_terms: D001021:Aortic Valve / Q000503:physiopathology; D001705:Bioprosthesis / Q000639:trends*; D003198:Computer Simulation; D003971:Diastole; D018618:Echocardiography, Doppler, Color / Q000379:methods; D004548:Elasticity; D006350:Heart Valve Prosthesis / Q000639:trends*; D006801:Humans; D057446:Hydrodynamics; D008422:Materials Testing / Q000295:instrumentation / Q000379:methods; D008955:Models, Cardiovascular; D011474:Prosthesis Design / Q000379:methods; D011475:Prosthesis Failure