title: Polymeric embolization coil of bilayered polyvinyl alcohol strand for therapeutic vascular occlusion: a feasibility study in canine experimental vascular models.
abstract: OBJECTIVE
  To investigate the feasibility of polyvinyl alcohol (PVA) polymer coil as a new endovascular embolic agent and to gauge the related histologic response in a canine vascular model.
  
  
  METHODS
  PVA polymer coil was fabricated by cross-linking PVA and tantalum particles. Basic properties were then studied in vitro via swelling ratio and bending diameter. Normal renal segmental arteries and wide-necked aneurysms of carotid sidewalls served as canine vascular models. Endovascular PVA coil embolization of normal renal segmental arteries (N = 20) and carotid aneurysms (N = 8) was performed under fluoroscopic guidance in 10 dogs. Degree of occlusion was assessed immediately and at 4 weeks after embolization by conventional and computed tomographic angiography. Histologic features were also graded at acute (day 1, six segmental arteries and four aneurysms) and chronic phases (week 4, 14 segmental arteries and four aneurysms) after embolization to assess inflammation, organization of thrombus, and neointimal proliferation.
  
  
  RESULTS
  Swelling ratio declined as concentrations of cross-linking agent increased. Mean bending diameters were 2.05 mm (range, 0.86-6.25 mm) in water at 37 °C and 2.29 mm (range, 0.94-6.38 mm) in canine blood samples at 37 °C. Occlusion of normal renal segmental arteries was sustained (complete occlusion at day 1, n = 20; at week 4, n = 14), whereas immediate outcomes in carotid aneurysms (day 1, complete occlusion, n = 5; residual neck only, n = 3) were not sustained (week 4, complete occlusion, n = 1; minor recanalization, n = 1; major recanalization, n = 2). At week 4, chronic inflammatory cells predominated, with progressive organization of thrombus and fibrocellular ingrowth. All aneurysms bore full neointimal linings on the coil mass in the chronic phase.
  
  
  CONCLUSIONS
  Vascular occlusion by PVA polymer coil proved superior in normal renal segmental arteries and feasible in surgically constructed carotid aneurysms (with packing densities ≥ 30%), constituting acceptable radiologic feasibility and histologic response.
authors.affiliation: Department of Radiology, Seoul National University College of Medicine, Seoul, Korea; Department of Radiology, Asan Medical Center, Seoul, Korea.
authors.forename: Seung Chai
authors.initials: SC
authors.lastname: Jung
authors.affiliation: Department of Radiology, Seoul National University College of Medicine, Seoul, Korea; School of Chemical and Biological Engineering and Center for Nanoparticle Research, Institute for Basic Science, Seoul, Korea; School of Chemical and Biological Engineering, Seoul National University, Seoul, Korea.
authors.forename: Seung Hong
authors.initials: SH
authors.lastname: Choi
authors.affiliation: Department of Radiology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Hye Rim
authors.initials: HR
authors.lastname: Cho
authors.affiliation: School of Chemical and Biological Engineering and Center for Nanoparticle Research, Institute for Basic Science, Seoul, Korea.
authors.forename: Tae Hoon
authors.initials: TH
authors.lastname: Lee
authors.affiliation: School of Chemical and Biological Engineering and Center for Nanoparticle Research, Institute for Basic Science, Seoul, Korea.
authors.forename: Tae Yang
authors.initials: TY
authors.lastname: Kim
authors.affiliation: Department of Mechanical Engineering, Myongji University, Seoul, Korea.
authors.forename: Woowon
authors.initials: W
authors.lastname: Jeong
authors.affiliation: Department of Mechanical Engineering, Myongji University, Seoul, Korea.
authors.forename: Kyehan
authors.initials: K
authors.lastname: Rhee
authors.affiliation: School of Chemical and Biological Engineering and Center for Nanoparticle Research, Institute for Basic Science, Seoul, Korea.
authors.forename: Jae Young
authors.initials: JY
authors.lastname: Jho
authors.affiliation: Department of Radiology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Jae Hyoung
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Radiology, Seoul National University College of Medicine, Seoul, Korea; Department of Neurosurgery, Seoul National University College of Medicine, Seoul, Korea. Electronic address: hanmh@snuh.org.
authors.forename: Moon Hee
authors.initials: MH
authors.lastname: Han
mesh_terms: D000818:Animals; D001157:Arterial Occlusive Diseases / Q000000981:diagnostic imaging / Q000628:therapy*; D002339:Carotid Arteries / Q000000981:diagnostic imaging; D016461:Chemoembolization, Therapeutic; D004195:Disease Models, Animal; D004285:Dogs; D005240:Feasibility Studies; D011142:Polyvinyl Alcohol / Q000008:administration & dosage*; D012077:Renal Artery / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed
chemical_list: D011142:Polyvinyl Alcohol