title: Impact of stent surface on thrombogenicity and vascular healing: a comparative analysis of metallic and polymeric surfaces.
abstract: BACKGROUND
  Emerging drug-eluting stent technologies are evolving toward the elimination of polymeric component used as the method for modulating drug delivery. Although this technological approach seems to be biologically appealing, the impact of durable polymers and metallic stent surfaces on vascular healing remains unclear. In the present study, we aimed to compare the independent effect of a durable polymer and a metallic stent surface on thrombogenicity and endothelial cell coverage using different in vitro and in vivo experimental models.
  
  
  RESULTS
  Platinum chromium (PtCr) and polyvinylidene fluoride-co-hexafluoropropene (PVDF-HFP)-coated surfaces were evaluated in this study. Thrombogenicity was assessed by exposing all surfaces to human blood under shear flow conditions. The inflammatory potential of the material was evaluated by measuring cytokine release from THP-1 cells exposed to all surfaces for 24 hours. Endothelial cell coverage was evaluated by detection of CD31 after the stents were exposed to human coronary artery endothelial cells for ≤ 14 days. Platelet adhesion (P<0.01) and activation (P=0.03) on PVDF-HFP were greater than on PtCr. In vivo, PVDF-HFP revealed more neointimal area (P<0.01) and residual parastrut fibrin (P=0.01) at 30 days compared with PtCr. PtCr displayed higher endothelialization rates and higher vascular endothelial-cadherin expression at 7 and 14 days (P=0.02) compared with PVDF-HFP.
  
  
  CONCLUSIONS
  Thrombogenicity and vascular healing differ among metallic and polymeric stent surfaces. PVDF-HFP exhibits higher degrees of platelet activation-adhesion and thrombus accumulation in vivo compared with PtCr. PtCr displayed higher degrees of endothelial surface coverage compared with PVDF-HFP surfaces.
authors.affiliation: Preclinical, Boston Scientific Corporation, Natick, MA, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Eppihimer
authors.forename: Natalia
authors.initials: N
authors.lastname: Sushkova
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Grimsby
authors.forename: Natalia
authors.initials: N
authors.lastname: Efimova
authors.forename: Wang
authors.initials: W
authors.lastname: Kai
authors.forename: Steve
authors.initials: S
authors.lastname: Larson
authors.forename: Bruce
authors.initials: B
authors.lastname: Forsyth
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Huibregtse
authors.forename: Keith D
authors.initials: KD
authors.lastname: Dawkins
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Wilson
authors.forename: Juan F
authors.initials: JF
authors.lastname: Granada
mesh_terms: D016207:Cytokines / Q000096:biosynthesis; D054855:Drug-Eluting Stents / Q000009:adverse effects*; D042783:Endothelial Cells / Q000502:physiology; D006801:Humans; D008670:Metals; D058426:Neointima; D015539:Platelet Activation; D010973:Platelet Adhesiveness; D011108:Polymers; D013499:Surface Properties; D013927:Thrombosis / Q000209:etiology*; D014945:Wound Healing
chemical_list: D016207:Cytokines; D008670:Metals; D011108:Polymers
keywords: drug-eluting stents; endothelial cells; polymers; thrombosis; vascular diseases