Postmarket Surveillance for Drug-Eluting Coronary Stents

Initial trials comparing stenting with balloon angioplasty demonstrated improved angiographic and clinical outcomes with the former.1–3 The main clinical problem with bare metal stents (BMS) became the development of in-stent restenosis.4–6 Early data suggested that drug-eluting stents (DES) could mitigate, if not abolish, this problem.7–9 Since the approval of DES, these devices have become the predominant stents used in percutaneous coronary interventions, regardless of indication. As of September 2007, the Cypher sirolimus-eluting stent (SES) (Cordis Johnson & Johnson, Miami Lakes, Fla) had been deployed in >3 million patients worldwide,10 and the millionth Taxus paclitaxel-eluting stent (PES) (Boston Scientific, Natick, Mass) was implanted as of January 2005.11 Over the past 2 years, numerous reports of very late stent thrombosis (ST) with first-generation DES have surfaced. This highly morbid complication and data suggesting that death and myocardial infarction (MI) may be more common with DES12,13 have altered the focus of trials and registries working to determine optimal DES use. There is a hope that second-generation DES will be less prone to ST as a result of differences in drug, stent design, and polymer. Medtronic, Inc (Minneapolis, Minn) presented safety and efficacy data to a public meeting of the US Food and Drug Administration (FDA) Circulatory System Devices Panel (CSDP) in October 2007 on its Endeavor zotarolimus-eluting stent (ZES), seeking approval for the indication of treating de novo native coronary lesions ≤27 mm with reference vessel diameters of 2.5 to 3.5 mm. The FDA asked the CSDP to determine whether the data presented demonstrated a reasonable level of safety and effectiveness, with clinical benefits clearly outweighing short- and long-term risks of ZES use. Important efficacy end points included ischemia-driven target lesion revascularization (TLR) or target vessel revascularization (TVR); safety end points included death, MI, and ST. The …

Primary percutaneous coronary intervention (P-PCI) is the preferred reperfusion strategy for patients with ST-segment elevation myocardial infarction if it can be performed rapidly by an experienced team.1 Compared with balloon angioplasty, routine bare-metal stent (BMS) implantation decreases risk for target vessel revascularization (TVR) and possibly reduces myocardial reinfarction rates but does not reduce mortality rates.2,3 Therefore, BMS has become the dominant P-PCI strategy, despite initial concern about increased stent thrombosis rates from delayed healing or inadequate late stent apposition due to initial thrombus trapping. Less established is the role of drug-eluting stents (DES) in P-PCI. DES have the potential to further decrease TVR rates but may increase risk for stent thrombosis. In fact, the risk of stent thrombosis might even be higher in P-PCI than in electively treated patients because of the combination of increased platelet activation, delayed healing, lack of endothelialization, and the proinflammatory and prothrombotic environment in the infarct artery.4 Article see p 103 Several relatively small randomized clinical trials have shown inconsistent efficacy for DES over BMS for P-PCI. Three meta-analyses of these trials have concluded that there is no difference in death or myocardial infarction rates, but TVR rates are decreased.5–7 Variably included were 12 studies that differed in trial design, inclusion criteria, end-point definitions, stent types, duration of clopidogrel treatment, and type of follow-up (angiographic versus clinical). They were limited by sample size and duration of follow-up and usually required angiographic documentation of stent thrombosis, which may have underestimated its true incidence. In this issue of Circulation: Cardiovascular Interventions , Kukreja et al8 report a single-center registry study that is an expanded version of a previous publication.9 Again including the 185 ST-segment elevation myocardial infarction patients treated with Sirolimus-eluting stents (SES) from April 2002 to February 2003, they compare …

Drug-eluting Stents at a Crossroads: the good, the Bad and the Ugly

The randomized clinical trials leading to initial approval of drug-eluting stents (DES) by the United States Food and Drug Administration were conducted by design in a homogeneous group of lower risk patients with mostly noncomplex coronary lesions.1,2 These studies demonstrated a clear benefit in the reduction of restenosis without any evidence of a safety concern during 1 year follow-up. Shortly after approval of the sirolimus and paclitaxel-eluting stents, safety and effectiveness was reported from small nonrandomized studies in a variety of more complex patient and lesion subgroups and resulted in a large proportion of so-called off-label usage.3,4 Article see p 176 Increased concern over the safety of acute DES implantation during primary percutaneous coronary intervention for ST elevation myocardial infarction (MI) left this indication as one of the last to gain widespread usage in favor of bare-metal stents (BMS). A study from Rotterdam comparing 186 consecutive patients receiving a DES from April 2002 to January 2003 with 183 patients receiving a BMS during an immediately preceding time interval demonstrated no increase in subacute stent thrombosis (0% versus 1.6%, P =0.10) and a significantly lower risk for major adverse cardiac events at 300 days (9.4% versus 17.0%, P =0.02) due to a markedly lower risk for target lesion revascularization (TLR) (1.1% versus 8.2%, P 80% penetration of DES among all percutaneous coronary intervention procedures by early 2006.6 Two small randomized trials of DES versus BMS conducted in Europe and published in September 2006, also showed no increase in stent thrombosis for DES within 1 year.7,8 In the summer of 2006, there were new concerns regarding late safety of DES with …

Percutaneous revascularization of left main coronary artery (LMCA) disease has remained controversial for more than 25 years, since LMCA balloon angioplasty was first performed by Andreas Gruentzig in 1978. Summarizing his experience, Gruentzig concluded, “We have not been too successful with dilating left main stems…although the procedure is relatively simple, the potential complications are both sudden and serious.”1 Following the evolution of percutaneous catheter-based therapies to include both bare metal stent and, more recently, drug-eluting stent (DES) platforms in conjunction with advances in periprocedural and postprocedural adjunctive pharmacotherapies, interest in percutaneous LMCA revascularization, particularly unprotected left main, has been renewed. Although studies performed with bare metal stents demonstrated a low rate of in-hospital mortality, the incidence of late coronary restenosis remained high.2–6 In the Unprotected Left Main Trunk Intervention Multi-Center Assessment (ULTIMA) registry, which enrolled 279 patients with unprotected LMCA disease who had percutaneous coronary revascularization (69% bare metal stent), mortality at a 1-year follow-up was proportional to clinical risk stratification (40% in high-risk versus 3.5% in low-risk patient cohorts), and repeated revascularization was required in 34% of cases.6 The experience gleaned from these studies continued to support the American College of Cardiology/American Heart Association (ACC/AHA) guideline recommendations that in reasonable surgical candidates with LMCA disease, coronary bypass surgery is the preferred therapeutic option.7 After the introduction of DES, several small clinical series demonstrated the feasibility and short-term safety of LMCA stenting, while late clinical/angiographic outcomes appeared favorable as compared with historical (nonrandomized) patient cohorts treated with bare metal stents.3,8–11 The cumulative experience with DES treatment for LMCA demonstrated an apparent marked reduction in major adverse cardiovascular events, including target vessel revascularization, during 6 to 12 months of follow-up as compared with the precedent experience after bare metal stent deployment. Article p 2542 The clinical …

In 1977, a major breakthrough in cardiovascular medicine was introduced by Dr. Andreas Gruentzig. In September of that year, Gruentzig performed the very first percutaneous transluminal coronary angioplasty (PTCA) procedure in a human. Twenty-three years later, the coronary artery was still patent. [1] Despite the initial enthusiasm, some complications were clearly associated with the procedure, being restenosis and thrombosis the major problems to deal with. In the early nineties, bare metal stents (BMS) were introduced to avoid the so called "elastic recoil of the artery" leading to restenosis. Despite some improvements in the rates of restenosis and thrombosis, they were still very significant. The introduction of dual antiplatelet therapy (thyenopiridine on top of aspirin) substantially decreased the rate of stent thrombosis, being currently a rare complication occurring in less than 1% of the procedures.

Comparison of Effectiveness of Bare Metal Stents Versus Drug-Eluting Stents in Large (≥3.5 mm) Coronary Arteries

Randomized trials have largely demonstrated that percutaneous coronary intervention (PCI) with sirolimus-eluting (SES) and paclitaxel-eluting stents (PES) results in a significant reduction in the occurrence of angiographic restenosis and revascularization compared with bare metal stents (BMS).1–4 The benefit of drug-eluting stents (DES) also has been confirmed in “real-world” scenarios. In this setting, when the analysis was focused on high-risk patient and lesion subgroups, a benefit still existed despite the presence of restenosis.5–7 These expanded indications do not yet cover many other types of complex lesions for which only registries or randomized trials, not yet published, are available so far (Tables 1 through 7⇓⇓⇓⇓⇓⇓). This topic is discussed in detail in this review. An important clarification is that the lack of proof is most probably due to the difficulty in performing randomized trials in high-risk groups using BMS as controls. It will be no surprise to find that the field in which DES perform best compared with BMS is likely to be complex lesions and patients8 (Figure 1). View this table: TABLE 1. DES in Unprotected Left Main Stenosis View this table: TABLE 2. DES in Bifurcation Lesions View this table: TABLE 3. DES in Chronic Total Occlusions View this table: TABLE 4. DES in Small-Vessel Disease and Long Lesions View this table: TABLE 5. DES in SVGs View this table: TABLE 6. DES in Acute MI View this table: TABLE 7. DES in Multivessel Disease Figure 1. Lesion complexity and stent performance in the BMS and DES eras. Adapted from Edelman et al.8 Current American Heart Association/American College of Cardiology (AHA/ACC) and European Society of Cardiology (ESC) guidelines consider the presence of a stenosis in the unprotected left main coronary artery (LMCA) a class IIa or IIb indication, respectively, for PCI if coronary artery bypass grafting (CABG) is not a viable option.9,10 Moreover, according to the AHA/ACC 2005 guidelines, in …

Drug-Eluting Stents and the Future of Coronary Artery Bypass Surgery: Facts and Fiction

<i>Circulation</i> Editors’ Picks

Four legs good, two legs better. — —George Orwell, Animal Farm, 1945 Since the earliest use of coronary stents for treating symptomatic coronary stenosis, maintaining patent arteries after treatment has remained an elusive goal. Although the first bare metal stents opened stenotic arteries, they injured the arterial wall. The buildup of intimal scar tissue caused restenosis, a frustrating problem for prevention or treatment. After a dozen years of research, however, drug-eluting stents were developed; armed with polymer coating and paclitaxel or sirolimus, they prevented restenosis and were hailed as a major therapeutic breakthrough. Article see p 141 Not long afterward, however, questions about the safety and efficacy of drug-eluting stents surfaced as reports of late stent thrombosis began to appear.1,2 Cardiologists wondered if prevention of restenosis was always a good thing. If no protective cellular layer formed over the struts of the drug-eluting stent—even months or years after implantation—would thrombus develop on the exposed metal scaffolding or other damaged or inflamed areas on the blood vessel wall? Over months or years, would progressive inflammation or late “catchup” tissue growth cause drug-eluting stents to lose their early advantage over bare metal stents? The pendulum in this debate has swung back and forth as clinical trials first raised concern about increased thrombosis and then later quelled our fears as our understanding of how drug-eluting stents work in real life has matured. An important issue has been the increased use of stents in patients with more complex coronary and other disorders, raising the question of whether the established standards of safety and efficacy still apply. Answers for these challenging questions have come from 2 worlds: clinical studies of patients with stents …

Introduced >20 years ago,1 coronary artery stents have improved the safety and particularly the efficacy of percutaneous coronary interventions (PCIs).2 Abrupt vessel closure, complicating 6% to 8% of balloon angioplasty procedures, was associated with a 5% mortality, 40% rate of myocardial infarction (MI), and 40% rate of emergency coronary artery bypass grafting.3 Stents significantly reduced these adverse events (Figure 1).4,5 The reduction of restenosis afforded by bare metal stents (BMS) was modest (30% to 40%). Repeat revascularization still occurred in 15% to 20% of cases.6 Drug-eluting stents (DES) with antiproliferative drugs attached via polymers on the stent surface to minimize smooth muscle proliferation have reduced restenosis and rates of target lesion revascularization by 50% to 70% compared with BMS across nearly all lesion and patient subsets.7 Initially8 and again more recently,9–16 safety concerns were raised about DES, particularly about late stent thrombosis (ST). Figure 1. Outcome of 112 patients with abrupt vessel closure in the prestent balloon angioplasty experience of a registry (1985 to 1986; total, 1801 patients)3 and 339 patients with abrupt vessel closure during balloon angioplasty treated with BMS (Palmaz-Schatz) (total, 4596 patients).5 CABG indicates coronary artery bypass grafting. ST was a bane of stent implantation from the beginning. The initial experience with Wallstents in the late 1980s was overshadowed by ST rates approaching 24%.17 Subsequent series with Palmaz-Schatz and Gianturco-Roubin stents (still predominantly bailout stenting) observed ST in 6% to 12% of cases.4,18 The postprocedural antithrombotic regimen at the time consisted of aspirin, often in conjunction with oral anticoagulation. Dual antiplatelet therapy of aspirin and the thienopyridine ticlopidine in conjunction with a shift from bailout to elective stenting resulted in a significant reduction of ST to <2%.5,19 Earlier oral antiplatelet drug loading and …

Outcomes associated with drug-eluting and bare-metal stents: a collaborative network meta-analysis

“Does it make economic sense to completely abandon a therapy that works well for 85% to 90% of the population for a new therapy costing four times as much to treat a transient health condition with no impact on either death or myocardial infarction?” J.M. Brophy and L.J. Erickson1 Since Andreas Gruntzig performed the first percutaneous coronary intervention (PCI) in 1977,2 the cost-effectiveness of this procedure has engendered major controversy. Debates have erupted over the clinical value and cost-effectiveness of each new device or therapy that has become available. Controversies have arisen regarding the cost of atherectomy, bare metal stents (BMS), brachytherapy, distal protection devices, glycoprotein IIb/IIIa inhibitors, and intravascular ultrasound.3–6 Drug-eluting stents (DES) are the most recent devices to have their cost scrutinized.7–12 Response by Ryan and Cohen p 1754 Balloon angioplasty is associated with restenosis rates of 30% to 40%, whereas PCI with BMS is associated with rates of 20% to 30%,13,14 and PCI with DES is associated with rates in the single digits.15,16 My colleagues and I pooled the results of 11 DES trials involving >5000 patients using a hierarchical Bayesian random-effects model.17 We found that, compared with BMS, DES reduce angiographic restenosis from 29.3% to 8.9% (Table 1 and Figure 1). There was no difference between DES and BMS in terms of mortality (0.9% versus 0.9%, respectively) or myocardial infarction (2.7% versus 2.9%, respectively). There was a suggestion that restenosis was less with sirolimus-eluting stents (SES) compared with polymeric paclitaxel-eluting stents (PES) (6.2% for SES versus 36.9% for BMS; 7.1% for PES versus 23.5% for BMS), a finding that was subsequently identified in another meta-analysis.18 View this table: TABLE 1. Clinical Events and Restenosis Rates in Randomized Clinical Trials Investigating DESs Figure 1. Forest plot comparing rates of angiographic restenosis for …

Since their commercial introduction in 2003, drug-eluting stents (DES) have rapidly altered the management of coronary artery disease. Before their development, the percutaneous management of coronary artery disease was performed predominantly by implantation of bare metal stents (BMS) made of either surgical stainless steel or metal alloys. Although such stents represented a considerable advance over balloon angioplasty alone, they remained limited by restenosis resulting from neointimal proliferation. As a result, ≈15% to 20% of patients treated with BMS required ≥1 repeat revascularization procedure within the 6 to 12 months after stent implantation.1 Despite numerous attempts at systemic pharmacotherapy, device modification, and even use of ionizing radiation, the rate of restenosis after BMS implantation remained largely unaffected. Response by Eisenberg p 1744 Over the past 5 years, effective DES have become the first device to substantially reduce the incidence of restenosis after stent implantation. By delivering high concentrations of either antiproliferative or immunomodulatory compounds directly to the site of arterial injury and by controlling this delivery through polymer-based drug release, both sirolimus- and paclitaxel-eluting stents have safely and effectively inhibited the proliferative process that results in in-stent restenosis. In pivotal clinical trials, both sirolimus- and paclitaxel-eluting stents have reduced rates of angiographic restenosis by 70% to 90% compared with conventional BMS designs, with parallel reductions in the need for clinically driven target vessel revascularization (TVR).2–4 As a result, in April 2003, DES were approved for use in clinical practice in the United States. Within 9 months of their introduction, DES made up 35% of all stent implantations in the United States,5 and their use has increased rapidly since that time. At our own institution, DES comprised >85% of all stents implanted during the past year, and national estimates are that >90% of all percutaneous coronary intervention (PCI) procedures …