title: Finite element analysis of the mechanical performances of 8 marketed aortic stent-grafts.
abstract: OBJECTIVE
  To assess numerically the flexibility and mechanical stresses undergone by stents and fabric of currently manufactured stent-grafts.
  
  
  METHODS
  Eight marketed stent-graft limbs (Aorfix, Anaconda, Endurant, Excluder, Talent, Zenith Flex, Zenith LP, and Zenith Spiral-Z) were modeled using finite element analysis. A numerical benchmark combining bending up to 180° and pressurization at 150 mmHg of the stent-grafts was performed. Stent-graft flexibility, assessed by the calculation of the luminal reduction rate, maximal stresses in stents, and maximal strains in fabric were assessed.
  
  
  RESULTS
  The luminal reduction rate at 90° was <20% except for the Talent stent-graft. The rate at 180° was higher for Z-stented models (Talent, Endurant, Zenith, and Zenith LP; range 39%-78%) than spiral (Aorfix, Excluder, and Zenith Spiral-Z) or circular-stented (Anaconda) devices (range 14%-26%). At 180°, maximal stress was higher for Z-stented stent-grafts (range 370-622 MPa) than spiral or circular-stented endografts (range 177-368 MPa). At 90° and 180°, strains in fabric were low and did not differ significantly among the polyester stent-grafts (range 0.5%-7%), while the expanded polytetrafluoroethylene fabric of the Excluder stent-graft underwent higher strains (range 11%-18%).
  
  
  CONCLUSIONS
  Stent design strongly influences mechanical performances of aortic stent-grafts. Spiral and circular stents provide greater flexibility, as well as lower stress values than Z-stents, and thus better durability.
authors.affiliation: Ecole Nationale Supérieure des Mines, Saint-Etienne, France. nicolas.demanget@gmail.com
authors.forename: Nicolas
authors.initials: N
authors.lastname: Demanget
authors.forename: Ambroise
authors.initials: A
authors.lastname: Duprey
authors.forename: Pierre
authors.initials: P
authors.lastname: Badel
authors.forename: Laurent
authors.initials: L
authors.lastname: Orgéas
authors.forename: Stéphane
authors.initials: S
authors.lastname: Avril
authors.forename: Christian
authors.initials: C
authors.lastname: Geindreau
authors.forename: Jean-Noël
authors.initials: JN
authors.lastname: Albertini
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Favre
mesh_terms: D017544:Aortic Aneurysm, Abdominal / Q000601:surgery; D001807:Blood Vessel Prosthesis; D020342:Finite Element Analysis; D055595:Mechanical Phenomena; D011474:Prosthesis Design; D015607:Stents