title: Inhibition of neointima formation after experimental coronary artery stenting: a new biodegradable stent coating releasing hirudin and the prostacyclin analogue iloprost.
abstract: BACKGROUND
  To minimize acute stent thrombosis and development of restenosis, stents coated with biodegradable and nonbiodegradable polymers have been proposed to serve as sustained-release drug carriers.
  
  
  RESULTS
  In both a sheep and a pig model, we examined the vascular response to standard and high-pressure implantation of coronary Palmaz-Schatz stents coated with a 10-microm layer of polylactic acid (MW 30 kDa) releasing recombinant polyethylene glycol (r-PEG)-hirudin and the prostacyclin analogue iloprost, both drugs with antithrombotic and potentially antiproliferative effects. Study observation time was 28 days. Between the corresponding stent groups, no differences were observed with regard to preplacement and postplacement implantation parameters. The morphometric analysis demonstrated that the coating was associated with a greater lumen diameter through a reduction in the mean restenosis area by 22.9% (P<0.02) in the standard-pressure model (sheep) and by 24.8% (P<0.02) in the overstretch pig model compared with uncoated control stents without inducing a local inflammatory response.
  
  
  CONCLUSIONS
  The results from this study demonstrate beneficial effects of a polymeric stent coating with polylactic acid releasing r-PEG-hirudin and iloprost on the development of restenosis after coronary stent placement at 4 weeks, independent of the extent of vascular injury. Future studies are proposed to investigate the integration of other substances to further enhance the potential of the stent coating on reducing neointimal formation.
authors.affiliation: I. Medizinische Klinik and Deutsches Herzzentrum, and the Department of Experimental Surgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany. alt@med1.med.tu-muenchen.de
authors.forename: E
authors.initials: E
authors.lastname: Alt
authors.forename: I
authors.initials: I
authors.lastname: Haehnel
authors.forename: C
authors.initials: C
authors.lastname: Beilharz
authors.forename: K
authors.initials: K
authors.lastname: Prietzel
authors.forename: D
authors.initials: D
authors.lastname: Preter
authors.forename: A
authors.initials: A
authors.lastname: Stemberger
authors.forename: T
authors.initials: T
authors.lastname: Fliedner
authors.forename: W
authors.initials: W
authors.lastname: Erhardt
authors.forename: A
authors.initials: A
authors.lastname: Schömig
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D000991:Antithrombins / Q000008:administration & dosage*; D003327:Coronary Disease / Q000517:prevention & control; D003331:Coronary Vessels; D016503:Drug Delivery Systems; D006629:Hirudins / Q000008:administration & dosage*; D016285:Iloprost / Q000008:administration & dosage*; D019344:Lactic Acid / Q000008:administration & dosage*; D011091:Polyesters; D011108:Polymers / Q000008:administration & dosage*; D012008:Recurrence; D012756:Sheep; D015607:Stents; D013552:Swine; D017539:Tunica Intima / Q000166:cytology
chemical_list: D000991:Antithrombins; D006629:Hirudins; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide); D016285:Iloprost