title: Effect of stent-graft compliance on endotension after EVAR.
abstract: OBJECTIVE
  To investigate whether, and to which extent, the type of graft has influence on the pressure in the aneurysm sac.
  
  
  METHODS
  The study consisted of a dynamic and a static experiment. In the dynamic experiment, a latex aneurysm was inserted into an in-vitro circulation model, with variable (80-180 mmHg) systemic systolic pressure and a pulse pressure of 40 mmHg. Seven types of devices were used to exclude the aneurysm: a latex reference graft, 3 stentless grafts made of different fabrics, and 3 different types of commercially produced stented grafts used for endovascular aneurysm repair (EVAR). The systolic and diastolic intra-aneurysm pressures (IAP) were measured, along with the pulse pressure. The mean IAP and pulse pressures were compared for each category of graft (stented/stentless) and for each graft. In the static experiments, the compliance of each graft and the latex aneurysm were determined by measuring the change in volume necessary to obtain a change in pressure. Furthermore, the IAP with each graft was measured in a nonpulsatile situation under systolic pressures varying between 60 and 140 mmHg.
  
  
  RESULTS
  The experiments showed that, with increasing systemic pressures, there was a small pressure (<5 mmHg) increase in the aneurysm, but there was no significant difference among grafts in the dynamic or the static experiments (p = 0.12 and p = 0.17, respectively). With the 3 stented EVAR grafts, there was less pressure transmission than with the 3 stentless grafts, but this difference was not significant (p>0.05).
  
  
  CONCLUSIONS
  This in-vitro study demonstrated that there is a clinically irrelevant pressure transmission through the graft wall and no significant difference in the pressure transmission between stented and stentless grafts.
authors.affiliation: Department of Surgery, Leiden University Medical Center, Leiden, The Netherlands. W.M.P.F.Bosman@lumc.nl
authors.forename: Willem-Maarten P F
authors.initials: WM
authors.lastname: Bosman
authors.forename: Jan-Willem
authors.initials: JW
authors.lastname: Hinnen
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Rixen
authors.forename: Jaap F
authors.initials: JF
authors.lastname: Hamming
mesh_terms: D000783:Aneurysm / Q000503:physiopathology / Q000601:surgery*; D001794:Blood Pressure; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000295:instrumentation*; D003187:Compliance; D019544:Equipment Failure Analysis; D007840:Latex / Q000737:chemistry; D008953:Models, Anatomic; D008955:Models, Cardiovascular; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011673:Pulsatile Flow; D015607:Stents; D013314:Stress, Mechanical
chemical_list: D007840:Latex