title: Transluminal stent graft repair with Wallgraft endoprosthesis in a porcine arteriovenous graft pseudoaneurysm model.
abstract: OBJECTIVE
  Pseudoaneurysm is a known complication of arteriovenous grafts in chronic hemodialysis and can result in graft disruption or thrombosis if left untreated. This study evaluated the safety and efficacy of endovascular repair with Wallgraft endoprosthesis (Boston Scientific, Inc, Watertown, Mass) in a porcine arteriovenous graft (AVG) pseudoaneurysm model.
  
  
  METHODS
  Bilateral groin AVG pseudoaneurysms (n = 18) were created with an oversized Dacron interposition graft within a polytetrafluoroethylene femoral AVG in nine domestic swine and allowed to mature 28 +/- 4 days (standard deviation). Transluminal placement of Wallgraft was performed to exclude the pseudoaneurysm from the AVG circulation. Hemodialysis was performed (400 mL/min x 1 hour, with intravenous heparin 30 units/kg) every 4 days for a total of 6 weeks via 15-gauge needles in the treated AVG pseudoaneurysm site. Arteriography and duplex ultrasound scan were performed to determine AVG patency and pseudoaneurysm flow. Histologic evaluation was performed to determine Wallgraft morphology. In vitro pulsatile flow chamber was used to determine maximal flow volume without peri-Wallgraft endoleak.
  
  
  RESULTS
  All AVG pseudoaneurysms were successfully excluded with the Wallgrafts. Twelve AVG (67%) remained patent at the completion of the study. No Wallgraft migration occurred from hemodialysis. Transient peri-Wallgraft endoleak (<2 hours after hemodialysis) was present in 13 of 18 (72%) and four of 12 (33%) AVG pseudoaneurysms by weeks 1 and 6, respectively. With maintenance of an intraluminal pressure of 80, 100, 120, 140, and 160 mm Hg in the pulsatile flow chamber, the maximal flow rates without peri-Wallgraft endoleak were 625 +/- 120, 650 +/- 145, 620 +/- 95, 425 +/- 110, and 262 +/- 86 mL/min. Scanning electron microscopy showed a neointimal layer covered with thrombus on the Wallgraft surface.
  
  
  CONCLUSIONS
  Endoluminal placement of Wallgraft endoprosthesis provides adequate structural support for continuous hemodialysis after AVG pseudoaneurysm exclusion. Transient blood flow in the pseudoaneurysm cavity may occur immediately after the hemodialysis, which may represent the effect of heparin used during hemodialysis. This study suggests Wallgraft is a safe and effective treatment for AVG pseudoaneurysm and permits continuous hemodialysis.
authors.affiliation: Division of Vascular Surgery & Endovascular Therapy, the Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston VAMC (112), 2002 Holcomb Blvd, Houston, TX 77030, USA. plin@bcm.tmc.edu
authors.forename: Peter H
authors.initials: PH
authors.lastname: Lin
authors.forename: Chris K
authors.initials: CK
authors.lastname: Johnson
authors.forename: Jennifer K
authors.initials: JK
authors.lastname: Pullium
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Koffron
authors.forename: Brian
authors.initials: B
authors.lastname: Conklin
authors.forename: Thomas T
authors.initials: TT
authors.lastname: Terramani
authors.forename: Ruth
authors.initials: R
authors.lastname: Bush
authors.forename: Changyi
authors.initials: C
authors.lastname: Chen
authors.forename: Alan B
authors.initials: AB
authors.lastname: Lumsden
mesh_terms: D017541:Aneurysm, False / Q000209:etiology / Q000628:therapy*; D000818:Animals; D001166:Arteriovenous Shunt, Surgical / Q000009:adverse effects*; D004195:Disease Models, Animal; D006435:Renal Dialysis; D015607:Stents; D013552:Swine