Recent progress in percutaneous coronary intervention: evolution of the drug-eluting stents, focus on the XIENCE V drug-eluting stent

Abstract

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.

Prospective, multi-center evaluation of a silicon carbide coated cobalt chromium bare metal stent for percutaneous coronary interventions: Two-year results of the ENERGY Registry

“…Drug-eluting stents (DES) were introduced to overcome this problem [2,4,5], but late and very late stent thrombosis of DES warranted further research [4,6,7]. To address these limitations, several novel technologies have been developed, one of them being BMS with an improved stent design.…”

“…To address these limitations, several novel technologies have been developed, one of them being BMS with an improved stent design. Cobalt-chromium (CoCr) replaced stainless steel, allowing thinner stent struts with the associated advantages of better flexibility and reduced restenosis rates [5,8,9]. In addition, passive stent coating may further reduce restenosis rates [10,11].…”

Treatment with Nesiritide, A Recombinant B-Type Natriuretic Peptide, Reduces Vascular Remodeling Following Balloon-Induced Endothelial Injuries in Rabbits

“…The advent of drug-eluting stents has significantly reduced the restenosis rate, but in-stent stenosis post-PCI remains a major concern (Doostzadeh et al 2010). It is possible to prevent restenosis by suppressing vascular remodeling through inhibition of plaque formation (neointimal hyperplasia) or by promoting vascular compensatory outward expansion.…”

“…Vascular remodeling of coronary and peripheral arteries remains a major complication following balloon-angioplasty, such as percutaneous coronary intervention (PCI) or stenting (Doostzadeh et al 2010). In mice, nesiritide decreases hypertrophy of heart muscles by elevating cGMP concentrations (Dickey et al 2007).…”

One‐year head to head comparison of the neointimal response between sirolimus eluting stent with reservoir technology and everolimus eluting stent

“…The coating is composed of an acrylic base and a fluorinated polymer that contains and releases 100 lg/cm 2 of the antiproliferative drug everolimus. Approximately 80% of drug is released within 30 days after implantation, with nearly full releasing within 4 months [11].…”