title: Computational estimation of the influence of the main body-to-iliac limb length ratio on the displacement forces acting on an aortic endograft. Theoretical application to Bolton Treovance® Abdominal Stent-Graft.
abstract: OBJECTIVE
  The influence of the relative iliac limb length of an endograft (EG) on the displacements forces (DF) predisposing to adverse effects are under-appreciated in the literature. Therefore, we conducted a computational study to estimate the magnitude of the DF acting over an entire reconstructed EG and its counterparts for a range of main body-to-iliac limb length (L1/L2) ratios.
  
  
  METHODS
  A customary bifurcated 3D model was computationally created and meshed using the commercially available ANSYS ICEM (Ansys Inc., Canonsburg, PA, USA) software. Accordingly, Fluid Structure Interaction was used to estimate the DF. The total length of the EG was kept constant, while the L1/L2 ratio ranged from 0.3 to 1.5.
  
  
  RESULTS
  The increase in L1/L2 slightly affected the DF on the EG (ranging from 3.8 to 4.1 N) and its bifurcation (4.0 to 4.6 N). However, the forces exerted at the iliac sites were strongly affected by the L1/L2 values (ranging from 0.9 to 2.2 N), showing a parabolic pattern with a minimum for 0.6 ratio.
  
  
  CONCLUSIONS
  It is suggested that the hemodynamic effect of the relative limb lengths should not be considered negligible. A high main body-to-iliac limb length ratio seems to favor hemodynamically a low bifurcation but it attenuates the main body-iliac limbs modular stability. Further clinical studies should investigate the relevant value of these findings. The Bolton Treovance(®) device is presented as a representative, improved stent-graft design that takes into account these hemodynamic parameters in order to achieve a promising, improved clinical performance.
authors.affiliation: Department of Vascular Surgery, "Democritus" Medical School, University Hospital of Alexandroupolis, Alexandroupolis, Greece - efstratiosgeorg@gmail.com.
authors.forename: E
authors.initials: E
authors.lastname: Georgakarakos
authors.forename: A
authors.initials: A
authors.lastname: Xenakis
authors.forename: G S
authors.initials: GS
authors.lastname: Georgiadis
authors.forename: C
authors.initials: C
authors.lastname: Argyriou
authors.forename: C
authors.initials: C
authors.lastname: Manopoulos
authors.forename: S
authors.initials: S
authors.lastname: Tsangaris
authors.forename: M K
authors.initials: MK
authors.lastname: Lazarides
mesh_terms: D001012:Aorta, Abdominal / Q000503:physiopathology / Q000601:surgery*; D017544:Aortic Aneurysm, Abdominal / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000295:instrumentation*; D003198:Computer Simulation; D017076:Computer-Aided Design; D057510:Endovascular Procedures / Q000295:instrumentation*; D006439:Hemodynamics; D006801:Humans; D007083:Iliac Artery / Q000503:physiopathology / Q000601:surgery*; D008955:Models, Cardiovascular; D011474:Prosthesis Design; D012039:Regional Blood Flow; D015607:Stents; D013314:Stress, Mechanical