Drug eluting stent for restenosis diseases

Drug-eluting stents (DESs) have been prevailing for the treatment of CAD in the interventional cardiology world owing to their efficacy in significantly reducing restenosis. Current successful DES requires a polymer coating for drug delivery. Clinical trials examining several pharmaceutical agents, particularly sirolimus and paclitaxel have demonstrated marked reduction in restenosis following stenting. The development of DES is one of the major revolutions in the field of ‘interventional cardiology’. Restenosis rate has been significantly reduced in comparison to bare metal stents. The ideal drug to prevent restenosis must have an anti-proliferative and anti-migratory effect on smooth muscle cells but on the other hand must also enhance re-endothelialization in order to prevent late thrombosis. Additionally, it should effectively inhibit the anti-inflammatory response after balloon induced arterial injury. Currently, sirolimus, paclitaxel and more recently ABT-578-eluting stents are commercially available, but ongoing research and clinical trials will result in new stents coming to market with novel designs loaded with a variety of compounds. Future research is mandatory to further clarify, whether these patients should be treated with the same DES with a different DES or with increased doses. Although, DES have significantly reduced angiographic restenosis rate and have improved the clinical outcome, late thrombosis and restenosis remain an important subject of ongoing research. Synthetic or biological polymers can be used as matrixes for drug incorporation, but concerns have been raised regarding biocompatibility, sterility or potential induction of inflammation. Currently, alterations on stent-backbone design (biodegradable, bioabsorbable, nanoporous etc.) are being explored