title: External stenting with a new polyester mesh reduces neointimal hyperplasia of vein grafts in a sheep model.
abstract: OBJECTIVE
  External stents placed around vein grafts have demonstrated effectiveness in reducing neointimal hyperplasia by preventing distension of the thin-walled vein grafts when exposed to arterial pressure. However, the ideal stent material has yet to be defined. The following study investigates the short- and long-term effects of an innovative polyester mesh stent designed with optimized adaptation of circumferential compliance.
  
  
  METHODS
  Following in vitro definition of the ideal macro-porous polyester stent material, a total of 12 sheep underwent implantation of bilateral carotid artery vein graft bypasses. In six sheep, the short term outcome (four weeks of implantation) was investigated by comparing the newly-designed stent to native veins, micro-porous PTFE stent grafts and metallic Biocompound stents (BCGs). Flow volume and graft diameter were measured prior to explantation. Grafts were evaluated histologically with respect to morphometry and immunoassaying. In the long-term group (6-month implantation time), the polyester stent was compared to native veins.
  
  
  RESULTS
  All stents effectively prevented dilatation of the graft. Perfused vessel diameters of the polyester veins were 8.3+/-0.6 mm. BCG as well as PTFE veins showed diameter reduction to 7.4+/-0.7 mm (p<0.05) and 7.8+/-0.4 mm (p<0.05), respectively. Both in the short and long terms, the new polyester stent led to significantly higher reduction of neointimal hyperplasia and luminal encroachment compared to the native vessel. It proved superior to PTFE stenting, while the Biocompound material failed to prove efficacy.
  
  
  CONCLUSIONS
  It was demonstrated that the new macro-porous polyester mesh stent reduced neointimal hyperplasia more effectively than other commercially available stents.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, J.W. Goethe University, Frankfurt, Germany.
authors.forename: A A
authors.initials: AA
authors.lastname: Klesius
authors.forename: M A
authors.initials: MA
authors.lastname: Konerding
authors.forename: P
authors.initials: P
authors.lastname: Knez
authors.forename: O
authors.initials: O
authors.lastname: Dzemali
authors.forename: T
authors.initials: T
authors.lastname: Schmitz-Rixen
authors.forename: H
authors.initials: H
authors.lastname: Ackermann
authors.forename: A
authors.initials: A
authors.lastname: Moritz
authors.forename: P
authors.initials: P
authors.lastname: Kleine
mesh_terms: D000818:Animals; D019917:Blood Vessel Prosthesis Implantation / Q000379:methods; D002340:Carotid Artery Diseases / Q000601:surgery; D017536:Carotid Artery, Common / Q000601:surgery; D004108:Dilatation, Pathologic / Q000517:prevention & control; D004195:Disease Models, Animal; D006083:Graft Occlusion, Vascular / Q000517:prevention & control*; D006965:Hyperplasia / Q000517:prevention & control; D011091:Polyesters / Q000627:therapeutic use*; D012501:Saphenous Vein / Q000473:pathology / Q000637:transplantation*; D012756:Sheep; D015607:Stents; D013526:Surgical Mesh; D017539:Tunica Intima / Q000473:pathology
chemical_list: D011091:Polyesters