Biocompatibility to reduce thrombogenicity of intracoronary stents

In interventional cardiology major technical advances have been accomplishe d in the last 20 years. Especially, the introduction of endovascular prosth eses (stents) was an important step forward. With the implantation of stent s in coronary arteries by Sigwart and colleagues over 10 years ago to manag e acute occlusion and restenosis after PTCA, the problems of thrombogenicit y and biocompatibility were evident. Strict anticoagulation had reduced the risk of in-stent thrombus formation. The problem of late neointimal prolif eration with development of restenosis is still not resolved. Many differen t designs, materials, and coatings were proposed to reduce thrombogenicity and optimize biocompatibility. Stent structure can influence flow condition s, surface charge can attract platelets or coagulation factors, and corrosi on with diffusing ions may induce proliferation of surrounding tissues. Ste nt surface treatment, several metal alloys, and drug-eluting or drug-stable coatings are under investigation to improve the short-term and long-term r esults. In the mid 1990s the introduction of an extended antiplatelet thera py and a new implantation technique with high-pressure stent deployment hav e improved the results. However, the optimal stent still does not exist. Th is article describes possible reasons and some new promising versions.