Next-generation drug-eluting stents in coronary artery disease: focus on everolimus-eluting stent (Xience V)

Clinical outcomes after zotarolimus and everolimus drug eluting stent implantation in coronary artery bifurcation lesions: insights from the RESOLUTE All Comers Trial

OBJECTIVE

We investigated clinical outcomes after treatment of coronary bifurcation lesions with second generation drug eluting stents (DES).

DESIGN

Post hoc analysis of a randomised, multicentre, non-inferiority trial.

SETTING

Multicentre study.

PATIENTS

All comers study with minimal exclusion criteria.

INTERVENTIONS

Patients were treated with either zotarolimus or everolimus eluting stents. The patient population was divided according to treatment of bifurcation or non-bifurcation lesions and clinical outcomes were compared between groups.

MAIN OUTCOMES MEASURES

Clinical outcomes within 2-year follow-up.

RESULTS

A total of 2265 patients were included in the present analysis. Two-year follow-up data were available in 2223 patients: 1838 patients in the non-bifurcation group and 385 patients in the bifurcation group. At 2-year follow-up the bifurcation and the non-bifurcation lesion groups showed no significant differences in terms of cardiac death (2.3 vs 2.1, p=0.273), target lesion failure (9.7% vs 13.8%, p=0.255), major adverse cardiac events (11.5% vs 15.1%, p=0.305), target lesion revascularisation (4.7% vs 6.0%, p=0.569), and definite or probable stent thrombosis (1.6% vs 1.8%, p=0.419).

CONCLUSIONS

The use of second generation DES for the treatment of coronary bifurcation lesions was associated with similar long term mortality and clinical outcomes compared with non-bifurcation lesions.

Longitudinal stent deformation: quantitative coronary angiographic analysis from the PERSEUS and PLATINUM randomised controlled clinical trials

AIMS

Recent reports have suggested susceptibility of novel thin-strut coronary stents to incur longitudinal stent deformation during or following deployment. This analysis assesses the incidence of longitudinal stent deformation in three stent platforms.

METHODS AND RESULTS

Quantitative angiographic analysis (QCA) of 2,403 stents from the PERSEUS Workhorse (WH) and PLATINUM-WH trials was performed by an independent core laboratory. The distribution of QCA measured: nominal stent length ratios was compared between platforms to evaluate longitudinal stent deformation. Stent length ratio averaged 0.95 ± 0.07 in the TAXUS Express arm and 0.94 ± 0.06 in the ION (TAXUS Element) arm of the PERSEUS-WH trial (p=0.16). In the PLATINUM-WH trial, the mean ratio in the PROMUS cohort was slightly smaller (0.92 ± 0.09) than PROMUS Element (0.94 ± 0.08; p=0.004). Manual, blinded re-examination by the core laboratory of the angiograms corresponding to the 20 lowest and highest ratios in each trial did not identify any cases of stent deformation.

CONCLUSIONS

Systematic analysis by an independent angiographic core laboratory of 2,403 stents implanted in patients enrolled in two large multicentre randomised trials demonstrated no stent deformation or meaningful differences in stent length ratios between ION and TAXUS Express or between PROMUS Element and PROMUS in the patient populations studied using the methodology employed.

Everolimus-eluting stent versus bare-metal stent in ST-segment elevation myocardial infarction (EXAMINATION): 1 year results of a randomised controlled trial

BACKGROUND

Everolimus-eluting stent (EES) reduces the risk of restenosis in elective percutaneous coronary intervention. However, the use of drug-eluting stent in patients with ST-segment elevation myocardial infarction (STEMI) is still controversial. Data regarding the performance of second-generation EES in this setting are scarce. We report the 1-year result of the EXAMINATION (clinical Evaluation of the Xience-V stent in Acute Myocardial INfArcTION) trial, comparing EES with bare-metal stents (BMS) in patients with STEMI.

METHODS

This multicentre, prospective, randomised, all-comer controlled trial was done in 12 medical centres in three countries. Between Dec 31, 2008, and May 15, 2010, we recruited patients with STEMI up to 48 h after the onset of symptoms requiring emergent percutaneous coronary intervention. Patients were randomly assigned (ratio 1:1) to receive EES or BMS. Randomisation was in blocks of four or six patients, stratified by centre and centralised by telephone. Patients were masked to treatment. The primary endpoint was the patient-oriented combined endpoint of all-cause death, any recurrent myocardial infarction, and any revascularisation at 1 year and was analysed by intention to treat. The secondary endpoints of the study included the device-oriented combined endpoint of cardiac death, target vessel myocardial infarction or target lesion revascularisation, and rates of all cause or cardiac death, recurrent myocardial infarction, target lesion or target vessel revascularisation, stent thrombosis, device and procedure success, and major and minor bleeding. This trial is registered with ClinicalTrials.gov, number NCT00828087.

FINDINGS

Of the 1504 patients randomised, 1498 patients were randomly assigned to receive EES (n=751) or BMS (n=747). The primary endpoint was similar in both groups (89 [11·9%] of 751 patients in the EES group vs 106 [14·2%] of 747 patients in the BMS group; difference -2·34 [95% CI -5·75 to 1·07]; p=0·19). Device-oriented endpoint (44 [5·9%] in the EES group vs 63 [8·4%] in the BMS group; difference -2·57 [95% CI -5·18 to 0·03]; p=0·05) did not differ between groups, although rates of target lesion and vessel revascularisation were significantly lower in the EES group (16 [2·1%] vs 37 [5·0%], p=0·003, and 28 [3·7%] vs 51 [6·8%], p=0·0077, respectively). Rates of all cause (26 [3·5%] for EES vs 26 [3·5%] for BMS, p=1·00) or cardiac death (24 [3·2%] for EES vs 21 [2·8%] for BMS, p=0·76) or myocardial infarction (10 [1·3%] vs 15 [2·0%], p=0·32) did not differ between groups. Stent thrombosis rates were significantly lower in the EES group (4 [0·5%] patients with definite stent thrombosis in the EES group vs 14 [1·9%] in the BMS group and seven [0·9%] patients with definite or probable stent thrombosis in the EES group vs 19 [2·5%] in the BMS group, both p=0·019). Although device success rate was similar between groups, procedure success rate was significantly higher in the EES group (731 [97·5%] vs 705 [94·6%]; p=0·0050). Finally, Bleeding rates at 1 year were comparable between groups (29 [3·9%] patients in the EES group vs 39 [5·2%] in the BMS group; p=0·19).

INTERPRETATION

The use of EES compared with BMS in the setting of STEMI did not lower the patient-oriented endpoint. However, at the stent level both rates of target lesion revascularisation and stent thrombosis were reduced in recipients of EES.

FUNDING

Spanish Heart Foundation.

Comparison of everolimus-eluting and sirolimus-eluting coronary stents: 1-year outcomes from the Randomized Evaluation of Sirolimus-eluting Versus Everolimus-eluting stent Trial (RESET)

BACKGROUND

Several recent randomized trials comparing everolimus-eluting stent (EES) and sirolimus-eluting stent (SES) reported similar outcomes. However, only 1 trial was powered for a clinical end point, and no trial was powered for evaluating target-lesion revascularization.

METHODS AND RESULTS

Randomized Evaluation of Sirolimus-eluting versus Everolimus-eluting stent Trial is a prospective multicenter randomized open-label trial comparing EES with SES in Japan. The trial was powered for evaluating noninferiority of EES relative to SES in terms of target-lesion revascularization. From February and July 2010, 3197 patients were randomly assigned to receive either EES (1597 patients) or SES (1600 patients). At 1 year, the primary efficacy end point of target-lesion revascularization occurred in 65 patients (4.3%) in the EES group and in 76 patients (5.0%) in the SES group, demonstrating noninferiority of EES to SES (P(noninferiority)<0.0001, and P(superiority)=0.34). Cumulative incidence of definite stent thrombosis was low and similar between the 2 groups (0.32% versus 0.38%, P=0.77). An angiographic substudy enrolling 571 patients (EES, 285 patients and SES, 286 patients) demonstrated noninferiority of EES relative to SES regarding the primary angiographic end point of in-segment late loss (0.06±0.37 mm versus 0.02±0.46 mm, P(noninferiority)<0.0001, and P(superiority)=0.24) at 278±63 days after index stent implantation.

CONCLUSIONS

One-year clinical and angiographic outcome after EES implantation was noninferior to and not different from that after SES implantation in a stable coronary artery disease population with relatively less complex coronary anatomy. One-year clinical outcome after both EES and SES use was excellent with a low rate of target-lesion revascularization and a very low rate of stent thrombosis.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01035450.

Everolimus-eluting stents in interventional cardiology

Bare metal stents have a proven safety record, but limited long-term efficacy due to in-stent restenosis. First-generation drug-eluting stents successfully countered the restenosis rate, but were hampered by concerns about their long-term safety. Second generation drug-eluting stents have combined the low restenosis rate of the first generation with improved long-term safety. We review the evolution of drug-eluting stents with a focus on the safety, efficacy, and unique characteristics of everolimus-eluting stents.

Nanoparticle-based drug delivery: case studies for cancer and cardiovascular applications

Nanoparticles (NPs) comprised of nanoengineered complexes are providing new opportunities for enabling targeted delivery of a range of therapeutics and combinations. A range of functionalities can be included within a nanoparticle complex, including surface chemistry that allows attachment of cell-specific ligands for targeted delivery, surface coatings to increase circulation times for enhanced bioavailability, specific materials on the surface or in the nanoparticle core that enable storage of a therapeutic cargo until the target site is reached, and materials sensitive to local or remote actuation cues that allow controlled delivery of therapeutics to the target cells. However, despite the potential benefits of NPs as smart drug delivery and diagnostic systems, much research is still required to evaluate potential toxicity issues related to the chemical properties of NP materials, as well as their size and shape. The need to validate each NP for safety and efficacy with each therapeutic compound or combination of therapeutics is an enormous challenge, which forces industry to focus mainly on those nanoparticle materials where data on safety and efficacy already exists, i.e., predominantly polymer NPs. However, the enhanced functionality affordable by inclusion of metallic materials as part of nanoengineered particles provides a wealth of new opportunity for innovation and new, more effective, and safer therapeutics for applications such as cancer and cardiovascular diseases, which require selective targeting of the therapeutic to maximize effectiveness while avoiding adverse effects on non-target tissues.

The twelve-month outcome of biolimus eluting stent with biodegradable polymer compared with an everolimus eluting stent with durable polymer

INTRODUCTION

Drug-eluting stents (DES) have significantly decreased the need for repeat coronary revascularization but concerns remain regarding the safety of first and second generation DES. We compared the safety and efficacy of a biolimus-eluting stent (with biodegradable polymer) with an everolimus-eluting stent (with durable polymer) one.

METHODS

We performed a randomized trial to compare the two types of stents. Two hundred patients undergoing PCI for de novo lesions were randomly assigned 1:1 to treatment with either biolimus-eluting (BioMatrix) or everolimus -eluting (Xience V) stent. The primary endpoint was a composite of cardiac death, myocardial infarction, and clinically driven target vessel revascularization within 12 months.

RESULTS

Demographics, clinical, and lesion characteristic were comparable between two groups. The 30-day major adverse car-diac event (MACE) rate was 2% in BioMatrix group versus 0% in Xience group (p > 0.05). After 12 months, the rates of cardiac death (0% in both groups), MI (2% versus 0%, p=0.49) and clinically -driven target vessel revascularization (0% in both groups) were similar for BioMatrix and Xience. No stent thrombosis was reported at 1, 6, 9 or 12 months after intervention in either group.

CONCLUSION

BES (Biolimus-eluting stent) with biodegradable polymer and EES (Everolimus-eluting stent) with durable polymer appear similar with respect to MACE and stent thrombosis in this patient population. Many studies with longer follow up are needed to define better the role of BES with biodegradable polymer in treatment of coronary artery lesions.

Everolimus: a proliferation signal inhibitor with clinical applications in organ transplantation, oncology, and cardiology

Everolimus, a proliferation signal inhibitor in the mammalian target of rapamycin (mTOR) drug class, has many clinical applications, including in organ transplantation, oncology, and cardiology. It currently has United States Food and Drug Administration (FDA) approval for prophylaxis against rejection in de novo renal transplant recipients, treatment of renal cell carcinoma, and use as a drug-eluting stent. To review the pharmacology, pharmacokinetics, efficacy, and safety of everolimus, we performed a search of the MEDLINE database (January 1997-April 2010) for all English-language articles of in vitro and in vivo studies that evaluated everolimus, as well as abstracts from recent scientific meetings and the manufacturer. In transplantation, everolimus demonstrates immunosuppressive properties and has been used to prevent acute rejection in cardiac, liver, lung, and renal transplant recipients. It appears that this agent may be potent enough to allow for the minimization or removal of calcineurin inhibitors in the long-term management of renal transplant recipients. In oncology, everolimus has been proven effective for the management of treatment-resistant renal cell carcinoma. In cardiology, everolimus is available as a drug-coated stent and is used in percutaneous coronary interventions for prevention of restenosis. In transplant recipients and patients with renal cell carcinoma, everolimus appears to have an extensive adverse-event profile. The pharmacologic properties of everolimus differentiate this agent from other drugs used in these clinical areas, and its pharmacokinetic properties differentiate it from sirolimus.

Novel drug-eluting stents in the treatment of de novo coronary lesions

Due to safety concerns in recent years, much effort has been devoted to improving the outcomes associated with drug-eluting stents (DESs). This review summarizes the current status of methodological and technical achievements reported in second-generation DES. Novel stents are described based on the component (the platform, the polymer, and the drug) that has undergone the most significant changes compared to earlier generation DES. An overview of the currently available evidence on the use of novel coronary devices in patients undergoing coronary revascularization is also reviewed.

Evaluation of the effects of everolimus-eluting and paclitaxel-eluting stents on target lesions with jailed side branches: 2-year results from the SPIRIT III randomized trial

OBJECTIVE

To evaluate whether an everolimus-eluting stent (EES) with thinner stent struts and polymer results in less periprocedural myonecrosis and adverse outcomes.

BACKGROUND

Higher periprocedural myocardial infarction (MI) rates have been reported with the TAXUS® EXPRESS(2) paclitaxel-eluting stent (PES) compared to the bare metal EXPRESS(2)® stent due to more frequent side branch compromise, presumably attributable to the thickness of the stent/polymer on the PES.

METHODS

In the SPIRIT III trial, we identified 113 patients in the XIENCE V® EES group and 63 patients in the TAXUS EXPRESS(2) PES group who met the criteria of having a lesion with a jailed side branch (<2 mm diameter, and <50% stenosis). Two-year clinical outcomes were evaluated.

RESULTS

A periprocedural increase in Creatine Kinase-MB >1× upper normal level occurred in 9.0% of EES compared to 29.7% of PES patients with jailed side branches, P = 0.01. Through 2 years, major adverse cardiac events (MACE; cardiac death, MI, or target lesion revascularization [TLR]) occurred in 6.8% of EES and 19.0% of PES jailed side branch patients (P = 0.03), with numerically lower rates of MI (2.9% vs. 10.3%, P = 0.07) and TLR (3.9% vs. 10.3%, P = 0.17) in the EES group, with comparable rates of cardiac death (1.9% vs. 1.7%, P = 1.00).

CONCLUSIONS

In this post-hoc analysis of the SPIRIT III RCT, patients undergoing stenting of target lesions with jailed side branches with the thin strut and polymer XIENCE V EES compared to the thicker strut TAXUS PES had lower rates of MACE through 2 years due to fewer MIs and TLRs. © 2010 Wiley-Liss, Inc.

Paclitaxel/sirolimus combination coated drug-eluting stent: in vitro and in vivo drug release studies

Paclitaxel and sirolimus are the two major drugs for the treatment of coronary arterial disease in current drug-eluting stents. The two drugs can effectively inhibit the in-stent restenosis through their independent pathways and show synergistic effect in preventing tumor tissue growth. We hypothesize that the combination of the two drugs in a drug-eluting stent (DES) can also effectively suppress the neointima growth in the stented artery. The present work was focused on the investigation of paclitaxel/sirolimus combination release profiles from a novel biodegradable polymer (poly (D, L-lactide-co-glycolide)/amorphous calcium phosphate, PLGA/ACP) coated stent both in vitro and in vivo. For the in vitro, the drug releasing profiles were characterized by measuring the drug concentration in a drug release medium (Dulbecco's phosphate buffered saline, DPBS, pH 7.4) at predetermined time points. For the in vivo, a rat aorta stenting model was employed. The results showed that both paclitaxel and sirolimus had a two-phase release profile both in vitro and in vivo, which is similar to the drug release profile of their individual coated DESs, and there is no evident of interference between two drugs. The data suggest that paclitaxel and sirolimus can be combined pharmacokinetically in a DES for the treatment of coronary arterial diseases.

Intravascular ultrasound assessment of cobalt chromium versus stainless steel drug-eluting stent expansion

It is not clear whether the thin struts and different alloy of a cobalt chromium stent will cause greater acute stent recoil compared to conventional stainless steel stents. We used postintervention intravascular ultrasound (IVUS) examinations to study 99 patients with 116 stented lesions: 61 Xience/Promus stents (cobalt chromium stent group) and 27 Taxus Liberté and 28 Cypher stents (stainless steel stent group). The IVUS images were obtained before and immediately after stent implantation with only the stent-delivery balloon. The ratio of the IVUS-measured to manufacturer-predicted stent diameter and area was the measure of acute stent recoil and expansion. The baseline patient characteristics, lesion morphology, and procedural details were comparable between the 2 groups. The ratio of the IVUS-measured to manufacturer-predicted stent diameter and area was 0.74 versus 0.73 (p = 0.57) and 0.63 versus 0.63 (p = 0.69), respectively, for the cobalt chromium and stainless steel stents. In conclusion, the acute performance of Xience/Promus was similar to that of previous stainless steel stents, and the thinner cobalt chromium metallic platform did not compromise the radial strength of the stent.

SPIRIT IV trial design: a large-scale randomized comparison of everolimus-eluting stents and paclitaxel-eluting stents in patients with coronary artery disease

BACKGROUND

In the 300-patient SPIRIT II and 1002-patient SPIRIT III randomized trials, the everolimus-eluting stent (EES) compared to the paclitaxel-eluting stent (PES) resulted in reduced angiographic late loss (a primary end point in both trials), noninferior rates of 9-month target vessel failure (a primary end point in SPIRIT III), and reduced rates of target lesion revascularization and major adverse cardiac events (secondary end points). However, neither trial was powered for superiority for clinical end points, and the routine performance of angiographic follow-up may have artificially exaggerated the absolute benefits of EES. The relative efficacy of these 2 stents in patients with diabetes mellitus also remains controversial. We therefore designed a large-scale randomized trial without angiographic follow-up to further assess the differences between these 2 stent platforms.

STUDY DESIGN

SPIRIT IV is an ongoing prospective, active-controlled, single-blinded, multicenter clinical trial in which 3690 patients with native coronary artery disease have been randomized 2:1 to EES versus PES. Patients with up to 3 de novo native coronary artery lesions (maximum 2 lesions per epicardial vessel) with length <or=28 mm and reference vessel diameter >or=2.5 to <or=4.25 mm were enrolled at 66 US clinical sites. Clinical follow-up at 30, 180, and 270 days; 1 year; and then yearly for up to 5 years is underway. The primary end point is the rate of ischemia-driven target lesion failure at 1 year, a composite measure of safety and efficacy consisting of cardiac death, target vessel myocardial infarction, or ischemia-driven target lesion revascularization, with the trial powered for sequential noninferiority and superiority testing.

SUMMARY

SPIRIT IV is the largest randomized comparison of 2 DES with completed enrollment. The absence of routine angiographic follow-up will allow an accurate assessment of the absolute differences in the clinical safety and efficacy profile between these devices. The magnitude of the study will also permit significant insights to be gained into the relative performance of the 2 stents in important subgroups, including patients with diabetes mellitus.

Rapamycin promotes arterial thrombosis in vivo: implications for everolimus and zotarolimus eluting stents

AIMS

Drug-eluting stents (DES) may be associated with an increased risk for stent thrombosis when compared with bare-metal stents. In endothelial cells, rapamycin induces tissue factor (TF) by inhibiting the mammalian target of rapamycin (mTOR). However, the effect of mTOR inhibition on TF activity and thrombus formation in vivo has not yet been studied. Moreover, it is unclear whether second-generation DES substances everolimus and zotarolimus have an effect on endothelial TF expression.

METHODS AND RESULTS

In a mouse carotid artery photochemical injury model, rapamycin (182 +/- 27.5 microg/L) decreased time to thrombotic occlusion by 40%, increased TF activity, and abrogated p70S6K phosphorylation when compared with controls. In vitro, rapamycin, everolimus, and zotarolimus (each 10(-7) mol/l) enhanced TNF-alpha-induced TF expression by 2.2-, 1.7-, and 2.4-fold, respectively, which was paralleled by an increase in TF surface activity. Similar to rapamycin, everolimus and zotarolimus abrogated TNF-alpha-induced p70S6K phosphorylation under these conditions.

CONCLUSION

Rapamycin increases TF activity and promotes arterial thrombosis in vivo at concentrations relevant in patients undergoing DES implantation; this effect may increase the thrombogenicity of DES. Since everolimus and zotarolimus augment endothelial TF expression and activity in vitro in a similar manner as rapamycin, these findings may also be relevant for second generation DES.

Efficacy of Xience/promus versus Cypher in rEducing Late Loss after stENTing (EXCELLENT) trial: study design and rationale of a Korean multicenter prospective randomized trial

BACKGROUND

The everolimus-eluting stent (EES) is a newly developed drug-eluting stent using the MULTILINK VISION stent platform combined with the drug everolimus contained in a polymer coating. Recently reported randomized trials have shown the noninferiority and subsequent superiority of the EES compared with the paclitaxel-eluting stent regarding in-stent late loss (LL) at 180 days. However, there have been no studies comparing head to head the EES with the sirolimus-eluting stent (SES), which has shown the least amount of LL among the previously released drug-eluting stent (DES). In addition, adjunctive antiplatelet therapy is a critical factor in optimizing long-term DES safety. Despite the recommendation of the American Heart Association/American College of Cardiology to maintain 12 months of dual antiplatelet therapy, there have been no prospective randomized trials comparing the efficacy and safety of different durations.

STUDY DESIGN

In the Efficacy of Xience/promus versus Cypher in rEducing Late Loss after stENTing (EXCELLENT) trial, approximately 1,400 patients are being prospectively and randomly assigned in a 2 x 2 factorial design according to the type of stent (EES vs SES) and the duration of dual antiplatelet therapy (6 vs 12 months). The primary end point is in-segment LL at 9 months for comparison of type of stent, and the coprimary end point is target vessel failure at 12 months for comparison of dual antiplatelet therapy duration.

SUMMARY

The EXCELLENT trial is the largest study yet performed to directly compare the efficacy and safety of the EES versus the SES. In addition, this study will also address the issue of a 6- versus 12-month duration of dual antiplatelet therapy for post-percutaneous coronary intervention management.

The evolution of cardiovascular stent materials and surfaces in response to clinical drivers: a review

This review examines cardiovascular stent materials from the perspective of a range of clinical drivers and the materials that have been developed in response to these drivers. The review is generally chronological and outlines how stent materials have evolved from initial basic stainless steel devices all the way through to the novel biodegradable devices currently being explored. Where appropriate, pre-clinical or clinical data that influenced decisions and selections along the way is referenced. Opinions are given as to the merit and direction of various ongoing and future developments.