title: Drug-eluting biodegradable poly-D/L-lactic acid vascular stents: an experimental pilot study.
abstract: OBJECTIVE
  To evaluate in vivo a new drug-eluting biodegradable vascular stent with respect to biocompatibility, neointimal hyperplasia formation, and reliability.
  
  
  METHODS
  Self-expanding biodegradable poly-96L/4D-lactic acid (PLA) stents with 2 drugs (PLA + dexamethasone [DEX] and PLA + simvastatin [SIM]) and 2 different coatings (PLA + P(D,L)LA and PLA + polycaprolactone [PCL]) were compared with a self-expanding stainless steel Wallstent. The stents were implanted in both common iliac arteries of 8 pigs. Prior to sacrifice at 1 month, angiography was performed to determine patency. Specimens were harvested for quantitative histomorphometry; vascular injury and inflammation scores were assigned to the stented iliac segments.
  
  
  RESULTS
  All stented arteries were angiographically patent. The mean luminal diameter (3.05 mm) and area (30.36 mm2) of DEX-eluting PLA stents were decreased compared to other stents (PLA + P(D,L)LA: 3.66 mm and 43.92 mm2; PLA + SIM: 4.21 mm and 56.48 mm2; PLA + PCL: 4.19 mm and 54.64 mm2; Wallstent: 5.01 mm and 81.19 mm2). Wallstents and DEX-eluting PLA stents induced minimal intimal hyperplasia: PLA + DEX: 0.16 mm, PLA + P(D,L)LA: 0.35 mm, PLA + SIM: 0.33 mm, PLA + PCL: 0.29 mm, and Wallstent: 0.18 mm. The vascular injury scores demonstrated only mild vascular trauma for all stents. Only mild to moderate inflammatory reaction was noted around stent struts with a vascular inflammation score.
  
  
  CONCLUSIONS
  Biodegradable polymer stents appear to be biocompatible and reliable, causing minimal neointimal hyperplasia. Furthermore, the new biodegradable poly-D/L-lactic acid stent can be used as a local drug delivery vehicle. The DEX-eluting PLA stent reduces neointimal hyperplasia. The findings show a need for further investigation to prove the efficacy and safety of this new biodegradable drug-eluting stent.
authors.affiliation: Department of Surgery, Satakunta Central Hospital, Pori, Finland. ilkka.uurto@uta.fi
authors.forename: Ilkka
authors.initials: I
authors.lastname: Uurto
authors.forename: Joonas
authors.initials: J
authors.lastname: Mikkonen
authors.forename: Jyrki
authors.initials: J
authors.lastname: Parkkinen
authors.forename: Leo
authors.initials: L
authors.lastname: Keski-Nisula
authors.forename: Timo
authors.initials: T
authors.lastname: Nevalainen
authors.forename: Minna
authors.initials: M
authors.lastname: Kellomäki
authors.forename: Pertti
authors.initials: P
authors.lastname: Törmälä
authors.forename: Juha-Pekka
authors.initials: JP
authors.lastname: Salenius
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D001157:Arterial Occlusive Diseases / Q000188:drug therapy / Q000473:pathology / Q000601:surgery; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000295:instrumentation*; D020099:Coated Materials, Biocompatible; D003907:Dexamethasone / Q000494:pharmacology; D004195:Disease Models, Animal; D005500:Follow-Up Studies; D005938:Glucocorticoids / Q000494:pharmacology; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology; D007083:Iliac Artery / Q000187:drug effects / Q000473:pathology / Q000601:surgery; D008297:Male; D010865:Pilot Projects; D011091:Polyesters; D011474:Prosthesis Design; D019821:Simvastatin / Q000494:pharmacology*; D015607:Stents; D013552:Swine
chemical_list: D020099:Coated Materials, Biocompatible; D005938:Glucocorticoids; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D011091:Polyesters; C016240:polycaprolactone; C033616:poly(lactide); D003907:Dexamethasone; D019821:Simvastatin