title: Small intestinal submucosa aneurysm sac embolization for endoleak prevention after abdominal aortic aneurysm endografting: a pilot study in sheep.
abstract: OBJECTIVE
  To percutaneously create an improved abdominal aortic aneurysm model of endoleak after endograft placement and to explore efficacy of small intestinal submucosal embolization of the residual aneurysmal sac for prevention of endoleaks.
  
  
  METHODS
  Abdominal aortic aneurysm was created transluminally by over-dilation of a Palmaz stent in 12 sheep. Approximately 20% undersized endografts suspended between two stent-graft adapters were used to bridge the aneurysm in a manner that two lumbar pairs remained patent within the residual aneurysm sac. Size of the residual aneurysm sac was increased by placement of an undersized stent-graft consisting of damaged lyophilized small intestinal submucosal sheets sandwiched between two Zilver stents. In six sheep, residual aneurysm sacs were embolized by combining small intestinal submucosal sponge and small intestinal submucosal sheet pieces. The other six sheep served as the control group. Angiography performed immediately after the procedure was compared with follow-up angiography before the animals were killed at 1, 3, and 7 months. Gross and histologic examinations were also obtained.
  
  
  RESULTS
  Aortic ruptures (n = 3) and dissections (n = 2) during aneurysm creation responded well to endograft placement. Eleven endografts were placed successfully, one was misplaced. The mean diameter of aneurysmal sac was 16 mm in the study and 15.2 mm in the control group. In the study group, in four sheep, the sac and seven pairs of lumbar arteries were occluded by embolization and remained obstructed by organized thrombus during the entire study. There were no type II endoleaks. Four type III new endoleaks developed without antegrade filling of lumbar arteries. In the control group, five animals had type I and II endoleaks at the initial studies. Only one sheep exhibited completely organized thrombosis of the aneurysmal sac and without endoleaks. In the other four sheep with partially organized sac thrombosis, endoleaks were unchanged. One type III endoleak occurred in this group.
  
  
  CONCLUSIONS
  The combination of small intestinal submucosal sponge and small intestinal submucosal sheet pieces is a promising embolic material for occlusion of the residual sac after endovascular abdominal aortic aneurysm repair and for prevention of type II endoleaks.
authors.affiliation: Dotter Interventional Institute, Oregon Health & Science University, Portland, 97201, USA.
authors.forename: Maria
authors.initials: M
authors.lastname: Schoder
authors.forename: Dusan
authors.initials: D
authors.lastname: Pavcnik
authors.forename: Barry T
authors.initials: BT
authors.lastname: Uchida
authors.forename: Christopher
authors.initials: C
authors.lastname: Corless
authors.forename: Hans A
authors.initials: HA
authors.lastname: Timmermans
authors.forename: Qiang
authors.initials: Q
authors.lastname: Yin
authors.forename: Elias
authors.initials: E
authors.lastname: Brountzos
authors.forename: Manabu
authors.initials: M
authors.lastname: Nakata
authors.forename: Takao
authors.initials: T
authors.lastname: Hiraki
authors.forename: Mahtab
authors.initials: M
authors.lastname: Niyyati
authors.forename: John A
authors.initials: JA
authors.lastname: Kaufman
authors.forename: Frederick S
authors.initials: FS
authors.lastname: Keller
authors.forename: Josef
authors.initials: J
authors.lastname: Rösch
mesh_terms: D000818:Animals; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery* / Q000628:therapy; D001027:Aortography; D019917:Blood Vessel Prosthesis Implantation; D004195:Disease Models, Animal; D004621:Embolization, Therapeutic / Q000295:instrumentation; D007421:Intestine, Small; D010865:Pilot Projects; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000517:prevention & control*; D012756:Sheep; D015607:Stents