Drug eluting stents (DESs) have revolutionized the interventional cardiology over the past decade since the first DES became commercially available in Europe in 2002. Compared to bare metal stents that are deployed to keep the vessel open by mechanical force, DESs have an additional function of reducing restenosis by the action of the drug on the target site. Coatings on the stent surface which ensure the maximum delivery of therapeutic agents to the target site with minimal systematic toxicity, also play an important role in adjusting the drug release profile. Coating material and technology not only affect the surface biocompatibility and the integrity maintenance during the implanting process, but also decide the way of drug delivering and transmitting from the coating. This paper reviews the basic principles of DES coating design, the categories of DES coatings, the commonly used clinical DES coatings and their efficiency in reducing restenosis, and finally provides the future perspectives for DES coatings.

Objective:To establish the biology reference interval (RI) of peripheral blood procalcitonin (PCT) for children between 3 days and 6 years old in China.Methods:Totally 3 353 reference individuals with apparent health or no specific diseases were recruited in 18 hospitals throughout the country during October 2020 to May 2021. Reference individuals were divided into four groups: 3-28 days, 29 days - 1 year, 1-3 years and 4-6 years. Vein blood or capillary blood were collected by percutaneous puncture from every reference individual. The PCT level in serum and the capillary whole blood were assayed by Roche Cobas e601 and Norman NRM411-S7 immunoanalyzer. Outliers were deleted and 95th percentiles of every group were provided as RIs. Man-Whitney U test or Kruskal-Wallis test were used performed to assess the difference among different gender, age or method groups. Results:The difference of PCT distribution between male and female is not statistically significant, but the difference between serum and capillary whole blood is statistically significant. The differences between age groups are significant too. For Roche e601, serum PCT RI of 3-28 days group is <0.23 μg/L, 29 days - 6 years are <0.11 μg/L. For NRM411, Serum PCT RI of 3-28 days group is <0.21 μg/L, 29 days - 1 year: <0.09 μg/L, 1 - 6 years: <0.10 μg/L. For whole blood PCT, RI of 3-28 days group is <0.26 μg/L, 29 days - 6 years is <0.15 μg/L.Conclusions:Serum and capillary whole blood PCT have different RIs, however, capillary whole blood PCT testing is valuable in pediatric application. Children in 3-28 days show higher PCT levels than other age group. To establish the RIs and understand the differences among different groups are essential for the interpretation and clinical application of peripheral blood PCT testing results.