Design criteria for the ideal drug-eluting Stent

The deployment of drug-eluting stents (DESs) is an integral treatment option for patients with coronary artery disease. Although the development and testing of the first-generation DESs focused to a considerable degree on efficacy parameters, including restenosis, recent concerns over late clinical events have prompted a refinement of the design criteria for succeeding generations of these devices. This review assesses design criteria for the ideal DES from 3 complementary perspectives: deliverability, efficacy, and safety. Most new investigational balloon-expandable DES systems have lowered crossing profiles by thinning stent struts using a cobalt chromium alloy, while investigational self-expanding DESs often use nitinol as the platform material. Stents designed to be fully biodegradable are also being developed, with deliverability and performance to be determined in future clinical trials. Refinements in bifurcation-dedicated stents will secure branch accessibility to offer better deliverability in complex lesion morphologies. Experimentation in stent design is already realizing multiple-lesion stenting and the in situ customization of stent length. Rather than simply targeting further reductions in restenosis rates, efforts to improve efficacy are shifting toward a lesion-specific approach, including the design of stents dedicated to bifurcation lesions. Another future direction U a disease-specific approach, or an approach using DESs as local drug-delivery devices. The identification of long-term safety issues with the first-generation DESs has reignited clinical interest in the development of stents that are more biologically based, including fully biodegradable stents and stents using biomimetic and biodegradable polymers. Important performance criteria for future DES agents include more cell-type specificity, broader safety margins, and greater facility at promoting endothelialization and healing. (C) 2007 Elsevier Inc. All rights reserved.