title: Occlusion of canine aneurysms using microporous self-expanding stent grafts: long-term follow-up.
abstract: OBJECTIVE
  The treatment of large or giant cerebral aneurysms by surgical and/or endovascular techniques is difficult and poses relatively high risks. Therefore, a microporous self-expanding (hybrid) stent graft composed of a thin, expandable, segmented polyurethane (SPU) membrane with micropores and a drug-delivery system was developed.
  
  
  METHODS
  A commercially available, self-expanding carotid stent was covered with a thin microporous SPU membrane fabricated by the dip-coating method and the excimer laser ablation technique, with an intraluminal coating of argatroban. Experimentally fabricated lateral-wall aneurysms in canine carotid arteries using venous pouches were occluded with the hybrid stent graft (bale-shaped pore density of 23.6%) on one side and a bare-metal stent on the other side without systemic antiplatelet therapy.
  
  
  RESULTS
  Angiography at 1, 6, and 12 months of stenting revealed that all arteries were patent without marked stenosis without systemic antiplatelet therapy. All aneurysms treated with hybrid stent grafts remained occluded throughout the 12-month period, while among those treated by bare-metal stents, 2 of 3 aneurysms were occluded at 6 months (67%) and only 1 of 3 aneurysms were occluded at 12 months (33%). Histology revealed that the novel hybrid stent graft had less intimal hyperplasia than the bare-metal stent. The hybrid stent graft was useful for the successful occlusion of these canine carotid aneurysms, even at 12 months.
  
  
  CONCLUSIONS
  The novel hybrid stent grafts are expected to overcome the disadvantages of fully covered stent grafts and simple bare-metal stents, while combining both their merits, and appear to be useful in the treatment of large or giant cerebral aneurysms.
authors.affiliation: Department of Neurosurgery, Interventional Neurosurgery, Spinal Surgery, Sapporo-Higashi Tokushukai Hospital, Sapporo, Hokkaido, Japan. Electronic address: nishi@higashi-tokushukai.or.jp.
authors.forename: Shogo
authors.initials: S
authors.lastname: Nishi
authors.affiliation: Department of Bioengineering, Advanced Biomedical Engineering Center, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan.
authors.forename: Yasuhide
authors.initials: Y
authors.lastname: Nakayama
authors.affiliation: Department of Pathology, National Cerebral and Cardiovascular Center Hospital, Suita, Osaka, Japan.
authors.forename: Hatsue
authors.initials: H
authors.lastname: Ishibashi-Ueda
authors.affiliation: Department of Neurosurgery, Nozaki Tokushukai Hospital, Osaka, Japan.
authors.forename: Yoshida
authors.initials: Y
authors.lastname: Masato
mesh_terms: D000818:Animals; D002340:Carotid Artery Diseases / Q000628:therapy*; D004195:Disease Models, Animal; D004285:Dogs; D004867:Equipment Design / Q000592:standards; D005260:Female; D005500:Follow-Up Studies; D002532:Intracranial Aneurysm / Q000628:therapy*; D015607:Stents / Q000592:standards*; D019737:Transplants / Q000592:standards
keywords: Canine experimental aneurysms; Covered stents; Hybrid stent grafts; Long-term follow-up; Microporous self-expanding stent graft