title: Polytetrafluoroethylene-encapsulated stent-grafts: use in experimental abdominal aortic aneurysm.
abstract: OBJECTIVE
  To evaluate expanded polytetrafluoroethylene (ePTFE) encapsulated stents for the treatment of aortic aneurysms with emphasis on the blood and tissue-material interactions.
  
  
  METHODS
  Experimental aortic aneurysms were created in dogs by enlarging the aortic lumen with an abdominal fascial patch. Twenty animals underwent endoluminal repair after allowing the surgically created aneurysm to heal for 2 months prior to transluminal aneurysmal exclusion. The device used consisted of an 8-cm-long ePTFE encapsulated stent graft. The animals were killed in groups at 1 week and at 1, 2.25, 6, and 12 months. Specimens were processed for histologic and luminal surface studies.
  
  
  RESULTS
  Before the animals were killed, aortography demonstrated two thrombosed aortae in the 6-month group and two endoleaks in the 12-month group. Endothelialized neointima extended into the proximal and distal portions of the prosthetic lumen, with minimal cell coverage in the center of the graft. The overall percent surface area covered by endothelialized neointima was 22% +/- 6% at 6 months and 18% +/- 10% by 1 year (P = .75). Histologic examination demonstrated minimal tissue penetration into the ePTFE.
  
  
  CONCLUSIONS
  Transluminal exclusion of abdominal aortic aneurysms by encapsulated stent-graft is easily accomplished. With this device, tissue coverage and penetration of the stent graft is limited and does not tend to increase with time.
authors.affiliation: University of Texas Health Science Center at San Antonio, Department of Radiology, 78284-7800, USA.
authors.forename: A E
authors.initials: AE
authors.lastname: Benson
authors.forename: J C
authors.initials: JC
authors.lastname: Palmaz
authors.forename: F O
authors.initials: FO
authors.lastname: Tio
authors.forename: E A
authors.initials: EA
authors.lastname: Sprague
authors.forename: C E
authors.initials: CE
authors.lastname: Encarnacion
authors.forename: S C
authors.initials: SC
authors.lastname: Josephs
mesh_terms: D000818:Animals; D001012:Aorta, Abdominal / Q000473:pathology / Q000601:surgery; D017544:Aortic Aneurysm, Abdominal / Q000473:pathology / Q000601:surgery*; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation; D004285:Dogs; D004730:Endothelium, Vascular / Q000473:pathology; D004867:Equipment Design; D011138:Polytetrafluoroethylene; D015607:Stents; D017539:Tunica Intima / Q000473:pathology; D014945:Wound Healing
chemical_list: D011138:Polytetrafluoroethylene