Doostzadeh Julie, Clark Lee N, Bezenek Susan, Pierson Wesley, Sood Poornima R, Sudhir Krishnankutty
Clinical Science Department, Abbott Vascular Inc., Santa Clara, California 95054, USA.
Coron Artery Dis. 2010 Jan;21(1):46-56. doi: 10.1097/MCA.0b013e328333f550.
Although originally the practice of using balloon catheters proved successful in the short term, the long-term prognosis was less promising because of restenosis, which occurred in >or=30% of patients. This prompted the development of new techniques and mechanical adjuncts, or stents, to maintain lumen patency after balloon angioplasty. Bare metal stents (BMS), the first type of stent used in percutaneous coronary intervention, were designed to address the issues met by balloon angioplasty. BMS reduced the angiographic and clinical restenosis rates in de novo lesions compared to percutaneous transluminal coronary angioplasty alone and decreased the need for emergency coronary artery bypass graft surgery. BMS substantially reduced the incidence of abrupt artery closure, but restenosis still occurred after 6 months in about 20% of cases, necessitating repeat procedures. Drug-eluting stents (DES) improved on the principle of BMS by also delivering drugs locally to inhibit neointimal hyperplasia. DES greatly reduced the incidence of restenosis and resulted in a better safety profile as compared to radiation or systemic drug administration. These advantages and a lower cost compared to surgical interventions make DES an attractive option to treat coronary artery disease. Currently, five DES are available in the USA: the CYPHER sirolimus-eluting stent from Cordis (approved by FDA on 24 April 2003), the TAXUS Express(2) and Liberté paclitaxel-eluting stents from Boston Scientific (approved by FDA on 4 March 2004 and 10 October 2008, respectively) (hereafter TAXUS Express is referred to as TAXUS), the ENDEAVOR zotarolimus-eluting stent from Medtronic (approved by FDA on 1 February 2008), and the XIENCE V everolimus-eluting stent from Abbott Vascular (approved by FDA on 2 July 2008). Following the approval of CYPHER and TAXUS, the clinical data suggested a potential small increase in the rate of stent thrombosis (ST) in DES compared with BMS after implantation. To determine the differences in ST and other rare events between different stents, some modifications have been made to DES clinical trial design, and postmarket surveillance programs have been included to further evaluate the safety and efficacy of each DES. In this review, we will discuss the key clinical outcomes of DES clinical trials, design and key features of the current coronary stents, and major clinical development programs. Postmarket trials, designed to establish long-term safety around ST and other rare clinical events, are also discussed. The future of DES design technologies will also be outlined.
尽管最初使用球囊导管的做法在短期内被证明是成功的，但由于再狭窄的发生，长期预后并不乐观，超过或等于30%的患者会出现再狭窄。这促使了新技术和机械辅助装置（即支架）的发展，以在球囊血管成形术后维持管腔通畅。裸金属支架（BMS）是经皮冠状动脉介入治疗中使用的第一种支架，旨在解决球囊血管成形术遇到的问题。与单纯经皮腔内冠状动脉血管成形术相比，BMS降低了初发病变的血管造影和临床再狭窄率，并减少了急诊冠状动脉搭桥手术的需求。BMS大幅降低了急性动脉闭塞的发生率，但仍有大约20%的病例在6个月后发生再狭窄，需要再次进行手术。药物洗脱支架（DES）在BMS的原理基础上进行了改进，还能局部释放药物以抑制内膜增生。与放射治疗或全身给药相比，DES大大降低了再狭窄的发生率，并具有更好的安全性。与手术干预相比，这些优势以及较低的成本使DES成为治疗冠状动脉疾病的一个有吸引力的选择。目前，美国有五种DES可供使用：科迪斯公司的西罗莫司洗脱支架CYPHER（2003年4月24日获得美国食品药品监督管理局批准）、波士顿科学公司的TAXUS Express(2)和利伯泰紫杉醇洗脱支架（分别于2004年3月4日和2008年10月10日获得美国食品药品监督管理局批准）（以下TAXUS Express简称为TAXUS）、美敦力公司的依维莫司洗脱支架ENDEAVOR（2008年2月1日获得美国食品药品监督管理局批准）以及雅培血管公司的XIENCE V依维莫司洗脱支架（2008年7月2日获得美国食品药品监督管理局批准）。在CYPHER和TAXUS获得批准后，临床数据表明，与植入BMS相比，DES植入后支架血栓形成（ST）率可能会有小幅上升。为了确定不同支架之间ST和其他罕见事件的差异，对DES临床试验设计进行了一些修改，并纳入了上市后监测计划，以进一步评估每种DES的安全性和有效性。在这篇综述中，我们将讨论DES临床试验的关键临床结果、当前冠状动脉支架的设计和关键特征以及主要的临床研发计划。还将讨论旨在确定围绕ST和其他罕见临床事件的长期安全性的上市后试验。DES设计技术的未来也将进行概述。
