Original articleIn Vitro Analyses of Diamond-like Carbon Coated Stents: Reduction of Metal Ion Release, Platelet Activation, and Thrombogenicity
Section snippets
Diamond-like Carbon Coated Stents
316 L stainless steel stents were coated on the inside and outside surfaces with diamond-like carbon (DLC) by a plasma-induced cold deposition technique (BioDiamond 9, Plasmachem, Mainz, FRG). Undeployed stents were 8.6 mm in length and were composed of four segments of DLC-coated 316L steel loops connected by a central bridging strut. The thickness of the stent wall (measured at both ends) was 60 μm±10%.
Sample Collection and Preparation of Platelet-rich Plasma and Plasma
The study was approved by the Institutional Review Board and the Local Ethical Committee.
Energy-Dispersive X-ray Microanalyses (EDX)
Semiquantitative energy-dispersive X-ray microanalyses showed the percentage elemental composition of the metal alloy to be 65.1% iron (Fe), 19.8% chromium (Cr), 12.0% nickel (Ni), and 0.003% sulfur (S). This elemental composition is characteristic of 316L stainless steel. The results of EDX were identical in coated and non-coated stent areas, because the process cannot detect carbon with atomic number six.
Atomic Adsorption Spectrophotometry (AAS) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS)
The interassay precision for nickel and chromium analyses was 12.9% and 4.7%,
Discussion
In spite of considerable progress in antithrombotic therapy and implantation techniques, interventional cardiological therapy and the use of stents in coronary arteries is still complicated by a substantial rate of thrombotic occlusions and restenoses 1, 6, 38, 39. Both conditions are associated with an increase in platelet activation, a non-physiological state that can be induced by metal ions 9, 10.
In this study, two intracoronay stent types (316L-stainless steel±DLC-coating) which only
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