Abstract and Introduction
Despite the impressive benefits obtained following the introduction of the drug-eluting stent, safety concerns have been raised over their long-term safety with particular regard to stent thrombosis. Various mechanisms such as delayed endothelialization, local hypersensitivity and endothelial dysfunction owing to the durable polymer coating and/or the drug itself have been suggested as possible causes of this phenomenon. Therefore, to address these concerns, a newer-generation of drug-eluting stents has been developed and they are currently undergoing preclinical and clinical evaluation in order to increase both the safety and biocompatibility by optimizing the three major components of drug-eluting stents: the stent platform, the polymer and the drug. This article critically reviews the key clinical trials and the current status of these new coronary devices as well as preventing future perspectives for their continued development.
The advent of drug-eluting stents (DESs) has considerably changed and revolutionized our ability to percutaneously approach more complex subsets of lesions in patients. In fact, DESs have resulted in lower rates of repeat revascularization as compared with bare-metal stents (BMSs)[1,2] at immediate and long-term follow-up. Even though first-generation DESs (Cypher®, sirolimus-eluting stent, Cordis, a Johnson and Johnson Company, NJ, USA and Taxus®, Boston Scientific, MA, USA) have performed well in terms of efficacy, enthusiasm for this technology has been dampened in the last few years. In fact, some studies have raised concerns in relation to their long-term safety and the risk of late stent thrombosis (ST) that is often associated with fatal consequences. Various mechanisms such as delayed endothelialization, local hypersensitivity and endothelial dysfunction owing to the durable polymer coating and/or the drug itself have been suggested as possible causes of this phenomenon and the need to prolong dual antiplatelet therapy (DAT).[4,5]
Therefore, the next generations of DESs were developed to increase both safety and biocompatibility by optimizing the three major components of DES: the stent platform, the polymer and the drug. Stents with thinner struts are endothelialized quicker, causing less vessel wall injury. Nondurable polymers applied thinly cause less inflammation and may result in better long-term safety. Furthermore, the use of biodegradable polymers, which fully degrade and leave a BMS, should result in less inflammation. Modern drugs with different release kinetics are also the object of study. In addition to the improvement in DES components, new approaches such as polymer-free drug delivery, a prohealing approach and fully biodegradable stents are also emerging.
Considering this background, we have reviewed the most important recent studies regarding new DES technology that are either under clinical evaluation or have recently been approved for use in everyday interventional practice.
Expert Rev Cardiovasc Ther. 2011;9(4):485-503. © 2011 Expert Reviews Ltd.
Cite this: Current and Future Drug-eluting Coronary Stent Technology - Medscape - Apr 01, 2011.