Abstract
Despite the success of drug-eluting stents (DES) in reducing restenosis and the need for target vessel revascularization, several deficiencies have been unraveled since their first clinical application including the risk of stent thrombosis, undesired effects due to the stent polymer as well as the stent itself, and incomplete inhibition of restenosis (especially in complex lesions). Several novel stent systems are being investigated in order to address these issues. In second-generation DES, the rapamycin analogues zotarolimus and everolimus (and more recently biolimus) have been most extensively studied. Furthermore, special stent-coatings to actively promote endothelial healing (in order to reduce the risk of stent thrombosis) and to further reduce restenosis have been employed. To avoid undesirable effects of currently applied (durable) polymers, biocompatible and bioabsorbable polymers as well as DES delivery systems without the need for a polymer have been developed. Bioabsorbable stents, both polymeric and metallic, were developed to decrease potential late complications after stent implantation. Although most of these innovative novel principles intuitively seem appealing and demonstrate good results in initial clinical evaluations, long-term large-scale studies are necessary in order to reliably assess whether these novel systems are truly superior to first-generation DES with respect to safety and efficacy.
Acknowledgements
Research by the authors was supported by the Swiss National Research Foundation (grant No. 3100-068118.02/1 to TFL and 3200B0-113328/1 to FCT) as well as by the European Union (grant no. G5RD-CT-2001-00532 to TFL), the Swiss Heart Foundation, the Wolfermann-Nägeli Foundation, the Bonizzi-Theler Foundation, the Velux Foundation, and the Center for Integrative Human Physiology of the University of Zurich. The authors received unrestricted research grants from Cordis, Biotronik, Boston Scientific, and Medtronic (TFL and FRE). Drs. Lüscher and Tanner are co-holders of a patent on the potential clinical applications of dimethyl sulfoxide.