title: Endotension as a result of pressure transmission through the graft following endovascular aneurysm repair--an in vitro study.
abstract: BACKGROUND
  endovascular aneurysm repair (EVAR) significantly reduces, but does not abolish aneurysm sac pressure, possibly because of trans-fabric transmission.
  
  
  OBJECTIVE
  to investigate how blood pressure is transmitted through different types of grafts into the aneurysm sac.
  
  
  METHODS
  experimental study, in vitro.
  
  
  METHODS
  a latex aneurysm was inserted into an in vitro circulation model. The systemic mean pressure (SPmean) was varied from 50 to 120 mmHg. The grafts used for aneurysm exclusion were: thin wall polyethylene (PE), thick wall polyethylene (PE) and thin wall ePTFE. Mean aneurysm sac pressure (ASPmean) was measured, as was pulse pressure (ASPpulse).
  
  
  RESULTS
  at an SPmean of 70 mmHg, the ASPmean was 34 +/- 0.8 mmHg (polyethylene knitted, thick wall), 30 +/- 1.0 mmHg (polyethylene woven, thin wall), and 17 +/- 0.6 mmHg (thin wall ePTFE). The ASPmean increased with SPmean, the relationship depending on the graft material. Stiffer grafts were associated with lower ASPmean and ASPpulse (p<0.001).
  
  
  CONCLUSIONS
  the relationship between aneurysm sac mean pressure and systemic pressure (SP) depends on the graft material. These data highlights the need for further studies regarding endotension.
authors.affiliation: Division of Vascular Surgery, Department of Surgery, Medical Center, University of Cologne, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Gawenda
authors.forename: G
authors.initials: G
authors.lastname: Jaschke
authors.forename: St
authors.initials: S
authors.lastname: Winter
authors.forename: G
authors.initials: G
authors.lastname: Wassmer
authors.forename: J
authors.initials: J
authors.lastname: Brunkwall
mesh_terms: D017544:Aortic Aneurysm, Abdominal / Q000503:physiopathology* / Q000601:surgery; D001696:Biomechanical Phenomena; D001794:Blood Pressure / Q000502:physiology*; D019917:Blood Vessel Prosthesis Implantation; D008955:Models, Cardiovascular; D008961:Models, Structural; D020959:Polyethylene; D011138:Polytetrafluoroethylene; D011474:Prosthesis Design; D011673:Pulsatile Flow
chemical_list: D011138:Polytetrafluoroethylene; D020959:Polyethylene