title: Forces at single point attached commissures (SPAC) in pericardial aortic valve prosthesis.
abstract: OBJECTIVE
  New pericardial aortic bioprostheses (3F Therapeutics and temporarily stented autologous pericardial valve prosthesis) were developed recently. These valves are designed with commissures connected to the aortic wall at only three single points (single point attached commissures (SPAC)). The aim of this study was to investigate the forces acting on SPAC during varying pressure load.
  
  
  METHODS
  Aortic roots with diameters 19, 25, and 29 mm were made using silicone polymer. A bovine pericardial SPAC aortic valve prosthesis was constructed using a 3D-mold and was implanted in the silicone aortic root. The base of the valve was sutured onto the aortic annulus with 4-0 polypropylene running suture and each commissure was sutured to a miniaturized force transducer with only one 3-0 polypropylene U-stitch. Three silicon aortic roots of each size were pressurized up to 200 mmHg and forces on SPAC were measured.
  
  
  RESULTS
  All valves remained competent at a pressure of 200 mmHg. Recordings showed a linear correlation between applied pressure and forces measured at SPAC. At a pressure of 80 mmHg (equivalent to diastolic pressure), the forces were 0.44+/-0.22N, 1.15+/-0.18N, and 2.00+/-0.35N in annular diameters 19 mm, 25 mm, and 29 mm, respectively. It was observed, that the main forces were acting along the axial direction and not along the radial direction.
  
  
  CONCLUSIONS
  Forces on "single point attached commissures" in pericardial aortic valves were measured. These forces were acting mainly in axial direction and not in radial direction. This knowledge is important for the implantation technique of SPAC pericardial aortic valves.
authors.affiliation: Nanyang Technological University, 50 Nanyang Avenue, School of Mechanical and Aerospace Engineering, Division of Thermal and Fluids Engineering, Singapore 639798, Singapore. wogoe@web.de
authors.forename: Wolfgang A
authors.initials: WA
authors.lastname: Goetz
authors.forename: Khee Hiang
authors.initials: KH
authors.lastname: Lim
authors.forename: Romain
authors.initials: R
authors.lastname: Ibled
authors.forename: Nil
authors.initials: N
authors.lastname: Grousson
authors.forename: Sidney Le Hung
authors.initials: Sle H
authors.lastname: Salgues
authors.forename: Joon Hock
authors.initials: JH
authors.lastname: Yeo
mesh_terms: D000818:Animals; D001021:Aortic Valve; D001705:Bioprosthesis; D002417:Cattle; D003198:Computer Simulation; D020342:Finite Element Analysis; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000379:methods; D006801:Humans; D008953:Models, Anatomic; D010496:Pericardium; D011474:Prosthesis Design; D012828:Silicones; D013314:Stress, Mechanical; D013536:Suture Techniques; D014159:Transducers
chemical_list: D012828:Silicones