Due to the body's own heterotropy, the introduction of cardiac vascular stents will make the body regard the stent as a foreign body and the site where the stent and artery membrane contact as the trauma area. Once there is a wound, the body has to repair it. An inflammatory reaction occurs in the stent of the artery. Many patients, especially diabetics, develop severe scar tissue proliferation around the metal stent. This scar tissue growth, in severe cases can cause open arteries to re-narrow, even blocked. Through the efforts of the researchers, finally combined the drug and the stent, that is, "plated" a layer of drug film on the surface of the metal stent, but the chemical characteristics of the metal stent itself is not easy to combine with the drug film, the metal itself needs to be modified, although the chemical modification method can increase the hydrophilicity of the metal, but there is still a little risk. For example, the residue of chemical agents, low temperature plasma treatment technology is a neutral and pollution-free dry treatment, which can not only clean the surface of the substrate, but also modify the surface of the substrate materials to improve the surface energy, wettability, activation and other properties of the substrate. When a coated stent is implanted in the body, the drug is slowly released, preventing scar tissue from growing around the stent and keeping the coronary arteries open.

The catheter is generally made of natural rubber, silicone rubber or polyvinyl chloride (PVC) material. Due to the poor biocompatibility of the material itself, plasma modification is needed to improve the wettability of the substrate, and the PVC surface is coated with triclosan and brominol. The modified PVC material can kill bacteria and resist bacterial adhesion. Thus, the patient infection caused by the material in the process of use is reduced, and the biocompatibility of the material is improved.