title: Differences of platelet adhesion and thrombus activation on amorphous silicon carbide, magnesium alloy, stainless steel, and cobalt chromium stent surfaces.
abstract: BACKGROUND
  Coronary stenting is considered to be the gold standard of percutaneous coronary interventions, because stents are able to reduce early and late elastic recoil (negative remodeling) and restenosis in comparison with balloon angioplasty alone.
  
  
  OBJECTIVE
  It is known that stent thrombogenicity and neointimal formation are determined by the surface characteristics of the stent platform, electrochemical features of the stent surface, and the degree of degradation after implantation. Metallic stents coated with amorphous silicon carbide and biodegradable stents made of magnesium alloy have been introduced clinically, but there are no data available comparing the biocompatibility of these novel stent materials with conventional stents.
  
  
  METHODS
  We demonstrate simple and reproducible in vitro methods assessing the rate of platelet adhesion and thrombus activation for biocompatibility tests of different stent surfaces.
  
  
  RESULTS
  We show that amorphous silicon carbide and magnesium alloy stent surfaces markedly lower the rate of platelet adhesion and platelet/fibrin activation when compared with uncoated stainless steel or cobalt chromium alloy surfaces. Semiconductor materials on the stent surface reduce platelet and fibrin activation by increasing the critical electron gap to greater than 0.9 eV resulting in a lower electron transfer out of the stent material.
  
  
  CONCLUSIONS
  Passive stent coatings with specific semiconducting properties such as amorphous silicon carbide or magnesium alloy reduce thrombogenicity and may improve biocompatibility of a stent platform.
authors.affiliation: Department of Cardiology and Angiology, University of Freiburg, Freiburg, Germany. christoph.hehrlein@uniklinik-freiburg.de
authors.forename: Christopher
authors.initials: C
authors.lastname: Hansi
authors.forename: Amina
authors.initials: A
authors.lastname: Arab
authors.forename: Alexander
authors.initials: A
authors.lastname: Rzany
authors.forename: Ingo
authors.initials: I
authors.lastname: Ahrens
authors.forename: Christoph
authors.initials: C
authors.lastname: Bode
authors.forename: Christoph
authors.initials: C
authors.lastname: Hehrlein
mesh_terms: D015906:Angioplasty, Balloon, Coronary / Q000009:adverse effects / Q000295:instrumentation*; D017554:Carbon Compounds, Inorganic; D002858:Chromium Alloys; D005337:Fibrin / Q000378:metabolism; D005340:Fibrinogen / Q000378:metabolism; D006801:Humans; D008274:Magnesium; D008422:Materials Testing; D010973:Platelet Adhesiveness; D011474:Prosthesis Design; D015203:Reproducibility of Results; D017655:Silicon Compounds; D013193:Stainless Steel; D015607:Stents; D013499:Surface Properties; D013927:Thrombosis / Q000097:blood / Q000209:etiology / Q000517:prevention & control*
chemical_list: D017554:Carbon Compounds, Inorganic; D002858:Chromium Alloys; D017655:Silicon Compounds; D013193:Stainless Steel; D005337:Fibrin; D005340:Fibrinogen; D008274:Magnesium; C022088:silicon carbide