Biocompatibility aspects of new stent technology.

Stent implantation represents a major step forward since the introduction of coronary angioplasty. As indications continue to expand, better understanding of the early and late biocompatibility issues appears critical. Persisting challenges to the use of intracoronary stents include the prevention of early thrombus formation and late neointima development. Different metals and designs have been evaluated in animal models and subsequently in patients. Polymer coatings have been proposed to improve the biocompatibility of metallic stents or to serve as matrix for drug delivery and they are currently undergoing clinical studies. The promises of a biodegradable stent have not yet been fulfilled although encouraging results have recently been reported. Continuous low dose-rate brachytherapy combining the scaffolding effect of the stent with localized radiation therapy has witnessed the development and early clinical testing of radioactive stents. The combined efforts of basic scientists and clinicians will undoubtedly contribute to the improvement of stent biocompatibility in the future.