Stent thrombosis late after implantation of first-generation drug-eluting stents: a cause for concern

Clinical outcomes with bioabsorbable polymer- versus durable polymer-based drug-eluting and bare-metal stents: evidence from a comprehensive network meta-analysis

OBJECTIVES

This study sought to investigate the relative safety and efficacy of bioabsorbable polymer (BP)-based biolimus-eluting stents (BES) versus durable-polymer (DP)-drug-eluting stents (DES) and bare-metal stents (BMS) by means of a network meta-analysis.

BACKGROUND

Studies have suggested that BP-BES might reduce the risk of stent thrombosis (ST) and late adverse outcomes compared with first-generation DES. However, the relative safety and efficacy of BP-BES versus newer-generation DES coated with more biocompatible DP have not been investigated in depth.

METHODS

Randomized controlled trials comparing BP-BES versus currently U.S.-approved DES or BMS were searched through MEDLINE, EMBASE, and Cochrane databases. Information on study design, inclusion and exclusion criteria, sample characteristics, and clinical outcomes was extracted.

RESULTS

Data from 89 trials including 85,490 patients were analyzed. At 1-year follow-up, BP-BES were associated with lower rates of cardiac death/myocardial infarction (MI), MI, and target vessel revascularization (TVR) than BMS and lower rates of TVR than fast-release zotarolimus-eluting stents. The BP-BES had similar rates of cardiac death/MI, MI, and TVR compared with other second-generation DP-DES but higher rates of 1-year ST than cobalt-chromium everolimus-eluting stents (CoCr-EES). The BP-BES were associated with improved late outcomes compared with BMS and paclitaxel-eluting stents, considering the latest follow-up data available, with nonsignificantly different outcomes compared with other DP-DES although higher rates of definite ST compared with CoCr-EES.

CONCLUSIONS

In this large-scale network meta-analysis, BP-BES were associated with superior clinical outcomes compared with BMS and first-generation DES and similar rates of cardiac death/MI, MI, and TVR compared with second-generation DP-DES but higher rates of definite ST than CoCr-EES.

Safety and efficacy outcomes of first and second generation durable polymer drug eluting stents and biodegradable polymer biolimus eluting stents in clinical practice: comprehensive network meta-analysis

OBJECTIVES

To investigate the safety and efficacy of durable polymer drug eluting stents (DES) and biodegradable polymer biolimus eluting stents (biolimus-ES).

DESIGN

Network meta-analysis of randomised controlled trials.

DATA SOURCES AND STUDY SELECTION

Medline, Google Scholar, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) database search for randomised controlled trials comparing at least two of durable polymer sirolimus eluting stents (sirolimus-ES) and paclitaxel eluting stents (paclitaxel-ES), newer durable polymer everolimus eluting stents (everolimus-ES), Endeavor and Resolute zotarolimus eluting stents (zotarolimus-ES), and biodegradable polymer biolimus-ES.

PRIMARY OUTCOMES

Safety (death, myocardial infarction, definite or probable stent thrombosis) and efficacy (target lesion and target vessel revascularisation) assessed at up to one year and beyond.

RESULTS

60 randomised controlled trials were compared involving 63,242 patients with stable coronary artery disease or acute coronary syndrome treated with a DES. At one year, there were no differences in mortality among devices. Resolute and Endeavor zotarolimus-ES, everolimus-ES, and sirolimus-ES, but not biodegradable polymer biolimus-ES, were associated with significantly reduced odds of myocardial infarction (by 29-34%) compared with paclitaxel-ES. Compared with everolimus-ES, biodegradable polymer biolimus-ES were associated with significantly increased odds of myocardial infarction (by 29%), while Endeavor zotarolimus-ES and paclitaxel-ES were associated with significantly increased odds of stent thrombosis. All investigated DES were similar with regards to efficacy endpoints, except for Endeavor zotarolimus-ES and paclitaxel-ES, which were associated with significantly increased the odds of target lesion and target vessel revascularisations compared with other devices. Direction of results beyond one year did not diverge from the findings for up to one year follow-up. Bayesian probability curves showed a gradient in the magnitude of effect, with everolimus-ES and Resolute zotarolimus-ES offering the highest safety profiles.

CONCLUSIONS

The newer durable polymer everolimus-ES and Resolute zotarolimus-ES and the biodegradable polymer biolimus-ES maintain the efficacy of sirolimus-ES; however, for safety endpoints, differences become apparent, with everolimus-ES and Resolute zotarolimus-ES emerging as the safest stents to date.

Accelerated endothelialization with a polymer-free sirolimus-eluting antibody-coated stent

Drug-eluting stents have shown an impressive reduction of in-stent restenosis for many years. However, stent thrombosis due to incomplete/late endothelialization has raised major safety concerns. To overcome these problems, we developed for the first time a polymer-free sirolimus-eluting antibody-coated stent (PFSEACS) by combining polymer free and endothelial progenitor cell-capture pro-healing approaches. In the first phase, the stents were prepared by loading sirolimus on the porous outer stent surface and directly fixing the anti-CD34 antibodies without any medium carriers on the blood contacting surface. The dose and elution of sirolimus, the amount and stability of anti-CD34 antibody immobilization, and the rate of CD34+ cell capture were evaluated. In the second phase, the stents were validated in an animal model of coronary arteries in pigs. The stent was observed to start collecting endothelial progenitor cells ~2 h after stent implantation and exhibited greatly enhanced endothelialization while maintaining an excellent anti-restenosis activity comparable to the polymer-free sirolimus-eluting stents. Overall, both in vitro and in vivo evaluations indicated that novel PFSEACSs exhibited facilitated endothelialization with excellent anti-restenosis activity and thus should merit further clinical studies.

A propensity score matched analysis to determine if second-generation drug-eluting stents outperform first-generation drug-eluting stents in a complex patient population

BACKGROUND

Drug-eluting stents (DES) are routinely used in complex patients, but the impact of 1st- versus 2nd-generation DES on clinical outcomes has not been well described. This study aimed to assess the efficacy and safety of 2nd-generation (everolimus-eluting) DES compared to 1st-generation (sirolimus- and paclitaxel-eluting) DES in a selected, higher-risk population with complex clinical and angiographic features.

METHODS

The study included 5693 consecutive patients with the presence of ≥ 1 predefined complex clinical and angiographic characteristic treated with either generation DES. Using propensity score matching, the clinical outcomes of 1076 patients treated with 2nd-generation DES were compared with the outcomes of a matched population treated with 1st-generation DES over 1-year follow-up.

RESULTS

After matching, baseline clinical and angiographic characteristics were similar between groups. At 1-year follow-up, the rate of major adverse cardiac events was 9.4% with 2nd-generation DES and 11.3% with 1st-generation DES (p=0.16). There were no significant differences in the rates of death (3.2 vs. 4.0%, p=0.30), myocardial infarction (1.6 vs. 1.3%, p=0.57), target vessel revascularization (5.9 vs. 7.3%, p=0.17) or target lesion revascularization (4.4 vs. 5.0%, p=0.50). Definite stent thrombosis was less frequent with 2nd-generation DES (0.1 vs. 0.8%, p=0.011), as was definite or probable stent thrombosis (0.7 vs. 1.6%, p=0.040).

CONCLUSION

In this propensity score matched patient population with complex features undergoing percutaneous coronary intervention, the use of 2nd-generation DES was associated with lower rates of stent thrombosis, and similar 1-year major adverse cardiac events compared to 1st-generation DES.

Miniaturized self-expanding drug-eluting stent in small coronary arteries: late effectiveness

Background

Small vessels represent a risk factor for restenosis in percutaneous coronary angioplasty (PCA). The Sparrow^® self-expanding drug-eluting stent, which has a lower profile than the current systems, has never been tested in this scenario.

Objectives

To evaluate the late effectiveness of the Sparrow^® drug-eluting stent, regarding in-stent late lumen loss (LLL).

Methods

Patients with ischemia, symptomatic or documented, were submitted to PCA in vessels with reference diameter < 2.75 mm, divided into two groups regarding Sparrow^® stent type: group 1: Sparrow^® drug-eluting stent (DES), group 2: Sparrow^® bare metal stent (BMS). Clinical follow-up duration was 12 months. Evaluation using quantitative coronary angiography (QCA) was performed immediately and at 8 months. A decrease of over 65% of in-stent LLL with DES was estimated to calculate sample size. IBM^® SPSS software, release 19 (Chicago, Illinois, USA) was used for the statistical analysis.

Results

A total of 24 patients were randomized, 12 in each group. The DES and BMS groups were similar in age (63.25 ± 10.01 vs. 64.58 ± 11.54, p = 0.765), male gender (58.3% vs. 33.3%, p = 0.412), risk factors and all angiographs aspects. Immediate results were satisfactory in both groups. At 8 months in-stent late lumen loss was significantly lower in DES than in BMS group (DES vs. BMS 0.25 ± 0.16 0.97 ± 0.76, p = 0.008).

Conclusion

In small-vessel PCA, the Sparrow^® DES determined significant reduction in in-stent LLL, when compared to Sparrow^® BMS.

A case report of very late stent thrombosis observed simultaneously in all three vessels 5 years after sirolimus-eluting stent implantation

A 67-year-old man with recent myocardial infarction underwent a total of five sirolimus-eluting stents (SES) implantation for three vessels stage by stage. A follow-up angiography showed no significant restenosis except one in the side branch. Thereafter, he had remained asymptomatic. Sixty-six months later, he had an acute myocardial infarction with cardiogenic shock due to simultaneous 3-vessel very late stent thrombosis (VLST). After successful percutaneous coronary intervention, final angiography revealed serious peri-stent contrast staining along with positive remodeling and grade V stent fracture. This rare case illustrates simultaneous 3-vessel VLST, associating with multiple SES-related problems, under continuation of aspirin and cilostazol.

Immobilization of R. erythropolis in alginate-based artificial cells for simulated plaque degradation in aqueous media

Cholesterol degradation rates of free and immobilized Rhodococcus erythropolis (ATCC # 25544) were studied utilizing the bacterium's cholesterol oxidase enzyme pathway to degrade cholesterol in an aqueous simulated non-calcified plaque solution. An L16 (4(5)) Taguchi design was used to minimize the glycolipid bio-surfactant by-product in the growth medium, to improve bacterial viability in the immobilized state. As an expected outcome of miniaturization, there is a significant difference between the atomized (d = 850 ± 50 μm) and inkjet-bioprinted (d = 32 ± 5 μm) lumped kinetic degradation rates after 48 h (p = 0.029, α = 0.05) per ml of jetted alginate. Based on a biphasic cholesterol degradation model, at an initial bacterial cell density of Nlow = 4.53 × 10(8)/ml, for an initial cholesterol concentration of 3 mg/ml, the percentage mass of metabolite degraded is 37.0% ± 0.42%, 57.8% ± 0.04% and 65.1% ± 0.01% for the free, atomized and inkjet immobilized bacteria, respectively.

Impact of the introduction of drug eluting stents on clinical outcomes in patients undergoing percutaneous and surgical coronary artery revascularisation procedures in Western Australia

Background

Increasing rates of percutaneous coronary intervention (PCI) and decreasing rates of coronary artery bypass graft (CABG) surgery followed the introduction of drug eluting stents in Western Australia in 2002. We assessed the impact of these changes on one-year outcomes for the total population of patients undergoing coronary artery revascularisation procedures (CARP) in Western Australia between 2000-2004.

Methods

Clinical and linked administrative data (inpatient admissions and death) were merged for all patients who had their first CARP with stent or CABG in Western Australia between 2000-2004. The clinical data were collected from all hospitals in Western Australia where CARP procedures are performed. We calculated the unadjusted (Kaplan-Meier) and adjusted (Cox) risks for one-year death (all-cause), death (all-cause) or admission for myocardial infarction (MI), target vessel revascularisation (TVR) and the composite outcome of death/MI/TVR (major adverse cardiac events, MACE).

Results

Over the study period, there were 14,118 index CARPs. The use of drug eluting stents increased from 0% to 95.8% of PCI procedures, and PCI procedures increased from 61.1% to 74.4% of all CARPS. There were no temporal changes in adjusted one-year mortality or death/MI. Overall, adjusted one-year MACE fell from 11.3% in 2000 to 8.5% in 2004 (p<0.0001) due to a significant reduction in TVR in the PCI group.

Conclusion

The introduction of drug eluting stents and resulting changes in coronary revascularisation strategies were not associated with changes in the one-year risk of major clinical endpoints (death or death/MI), but were associated with a significant reduction in the risk of MACE, driven entirely by a reduction in TVR after PCI. This real world study supports the effectiveness of drug eluting stents in reducing repeat procedures in the total CARP population without increasing the risk of death or MI.

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.

Progress in treatment by percutaneous coronary intervention: the stent of the future

First generation drug-eluting stents have considerably reduced in-stent restenosis and broadened the applications of percutaneous coronary interventions for the treatment of coronary artery disease. The polymer is an integral part of drug-eluting stents in that, it controls the release of an antiproliferative drug. The main safety concern of first generation drug-eluting stents with permanent polymers--stent thrombosis--has been caused by local hypersensitivity, delayed vessel healing, and endothelial dysfunction. This has prompted the development of newer generation drug-eluting stents with biodegradable polymers or even polymer-free drug-eluting stents. Recent clinical trials have shown the safety and efficacy of drug-eluting stents with biodegradable polymer, with proven reductions in very late stent thrombosis as compared to first generation drug-eluting stents. However, the concept of using a permanent metallic prosthesis implies major drawbacks, such as the presence of a foreign material within the native coronary artery that causes vascular inflammation and neoatherosclerosis, and also impedes the restoration of the vasomotor function of the stented segment. Bioresorbable scaffolds have been introduced to overcome these limitations, since they provide temporary scaffolding and then disappear, liberating the treated vessel from its cage. This update article presents the current status of these new technologies and highlights their future perspectives in interventional cardiology.

Benefits and risks of long-term duration of dual antiplatelet therapy after drug-eluting stenting: a meta-analysis of randomized trials

BACKGROUND

The potential benefits and risks of at least 1-year dual antiplatelet therapy (DAPT) duration after drug-eluting stent (DES) implantation remain uncertain.

METHODS AND RESULTS

PubMed, the Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov databases were searched from database inception to December 2011 for randomized controlled trials that compared longer DAPT versus shorter DAPT duration after DES. Unpublished data were obtained from investigators. Trial-specific odds ratios (ORs) with 95% confidence interval (CI) were calculated and pooled using fixed-effects or random-effects model as appropriate. Data were independently extracted by 2 reviewers. Three randomized controlled trials comprising 5622 participants were included. Compared with patients receiving short-term therapy, participants receiving longer DAPT duration had a pooled OR of 1.26 (95% CI, 0.88 to 1.80; P=0.21, random-effects) for the primary outcome of cardiac death, myocardial infarction or stroke, OR of 1.29 (95% CI, 0.85 to 1.93; fixed-effects) for all-cause death, 1.23 (95% CI, 0.78 to 1.93; fixed-effects) for cardiac death, 0.91 (95% CI, 0.58 to 1.42; random-effects) for myocardial infarction, 1.93 (95% CI, 1.01 to 3.69; fixed-effects) for stroke and 2.51 (95% CI, 1.10 to 5.71, fixed-effects) for TIMI major bleeding. The number needed to treat for an additional harmful outcome was 217.6 for stroke and 243 for TIMI major bleeding.

CONCLUSIONS

This meta-analysis provides no evidence of benefits with longer DAPT duration as compared with a shorter course of therapy. It also reports significant harms with respect to major bleeding and stroke associated with prolonged DAPT use.

Paclitaxel drug-coated balloons: a review of current status and emerging applications in native coronary artery de novo lesions

The paclitaxel drug-coated balloon (DCB) is an emerging device in percutaneous coronary intervention, which has shown promising results by means of a high-concentration, rapid local release of an antirestenotic drug without the use of a durable polymer or metal scaffold. DCB have already proven effective in clinical trials for the treatment of in-stent restenosis. Its coronary applications may potentially be widened to a host of complex coronary de novo lesion subsets, such as small-caliber vessels, diabetes, and diffuse lesions, where the use of stents may be hampered by suboptimal results. Recently, this technology has rapidly evolved with newer studies added to assess the value of DCB in coronary applications other than in-stent restenosis. We present a review of the role of DCB in de novo coronary lesions based on this latest clinical evidence.

Trends in hospital discharges, management and in-hospital mortality from acute myocardial infarction in Switzerland between 1998 and 2008

Background

Since the late nineties, no study has assessed the trends in management and in-hospital outcome of acute myocardial infarction (AMI) in Switzerland. Our objective was to fill this gap.

Methods

Swiss hospital discharge database for years 1998 to 2008. AMI was defined as a primary discharge diagnosis code I21 according to the ICD10 classification. Invasive treatments and overall in-hospital mortality were assessed.

Results

Overall, 102,729 hospital discharges with a diagnosis of AMI were analyzed. The percentage of hospitalizations with a stay in an Intensive Care Unit decreased from 38.0% in 1998 to 36.2% in 2008 (p for trend < 0.001). Percutaneous revascularizations increased from 6.0% to 39.9% (p for trend < 0.001). Bare stents rose from 1.3% to 16.6% (p for trend < 0.001). Drug eluting stents appeared in 2004 and increased to 23.5% in 2008 (p for trend < 0.001). Coronary artery bypass graft increased from 1.0% to 3.0% (p for trend < 0.001). Circulatory assistance increased from 0.2% to 1.7% (p for trend < 0.001). Among patients managed in a single hospital (not transferred), seven-day and total in-hospital mortality decreased from 8.0% to 7.0% (p for trend < 0.01) and from 11.2% to 10.1%, respectively. These changes were no longer significant after multivariate adjustment for age, gender, region, revascularization procedures and transfer type. After multivariate adjustment, differing trends in revascularization procedures and in in-hospital mortality were found according to the geographical region considered.

Conclusion

In Switzerland, a steep rise in hospital discharges and in revascularization procedures for AMI occurred between 1998 and 2008. The increase in revascularization procedures could explain the decrease in in-hospital mortality rates.

An update on drug-eluting stents

OPINION STATEMENT

Coronary artery disease remains one of the major causes of morbidity and mortality worldwide. Percutaneous coronary intervention has been shown to be an effective treatment for angina pectoris, although it does not provide any prognostic benefit in stable patients. Drug-eluting stents (DES) have revolutionised the practice of interventional cardiology by permitting the percutaneous treatment of increasingly complex coronary artery lesions, which historically would have only been treated with surgery. There have been concerns with their long-term safety; however, the most recent large meta-analysis appears to suggest that these concerns are no longer a pertinent issue with the newest generation of stents. Consequently, DES are being used in complex patients and lesion types, and clinical data and guideline recommendations support this. New stent designs are also continually being developed, with the aim to further improve the safety profile of these devices. It must, however, be kept in mind that complacency following the impressive result from initial DES studies lead to, amongst others things, sub-optimal and careless stent deployment, and inappropriate patient selection, which may have ultimately contributed to the prior safety concerns. It is vital, therefore, that this is not repeated in light of the reassuring data, or with newer devices. Finally, as stent design improves, it is becoming increasingly difficult to identify meaningful and clinically relevant differences in stent performance without the requirement of a very large, expensive, randomised trial.

Coronary stents: historical development, current status and future directions

INTRODUCTION

Coronary angioplasty with stenting has revolutionized the treatment of coronary artery disease. This article describes the history of coronary angioplasty and stenting, reviews the contemporary stents and recommendations and highlights the on-going work and potential future directions.

SOURCES OF DATA

This review examined the data on coronary stents available in PubMed.

AREAS OF AGREEMENT

Coronary artery stenting is the treatment of choice for patients requiring coronary angioplasty. Stents, and particularly drug-eluting stents, reduce the risk of restenosis, but may be associated with the hazard of late stent thrombosis. Dual anti-platelet treatment is recommended for patients receiving coronary stents.

AREAS OF CONTROVERSY

The selection of stents for various lesions and patients and the duration of anti-platelet therapy remain debated areas.

AREAS TIMELY FOR DEVELOPING RESEARCH

There are on-going preclinical and clinical studies to develop better stent platforms, more biocompatible polymers, novel anti-proliferative and anti-platelet drugs, pro-healing stents and bioresorbable scaffolds.

Real-world use of the second-generation cobalt-chromium sirolimus-eluting stents: 12-month results from the prospective multicentre FOCUS registry

AIMS

The FOCUS registry is a prospective, multicentre, web-based programme designed to collect clinical outcome data from real-world patients receiving the second-generation cobalt-chromium sirolimus-eluting stent (CoCr-SES).

METHODS AND RESULTS

From March 2009 to February 2010, a total of 5,084 patients from 83 centres who were eligible to receive CoCr-SES were enrolled in the FOCUS registry. The primary endpoint was 12-month major adverse cardiac events (MACE, defined as the composite of cardiac death, myocardial infarction [MI], and target vessel revascularisation [TVR]). One-year data were available for 5,013 (98.6%) of the 5,084 patients enrolled. The primary endpoint occurred in 174 (3.47%) of 5,013 patients, consisting of 43 (0.86%) cardiac deaths, 132 (2.63%) MI, and 46 (0.92%) TVR. According to the Academic Research Consortium definition, definite and probable stent thrombosis (ST) occurred in 0.52% (26/5,013) of patients, including 19 cases of early ST and 7 of late ST. The 12-month MACE rates were 3.73% and 2.60% for extended-use and standard-use patients, respectively (p=0.065).

CONCLUSIONS

The second-generation CoCr-SES was associated with low rates of 12-month MACE and ST in a broad spectrum of patients, thereby confirming the clinical safety and efficacy of this stent in a real-world setting.

Comparison of drug-eluting stents in acute myocardial infarction patients with chronic kidney disease

BACKGROUND/AIMS

To determine which drug-eluting stents are more effective in acute myocardial infarction (MI) patients with chronic kidney disease (CKD).

METHODS

This study included a total of 3,566 acute MI survivors with CKD from the Korea Acute Myocardial Infarction Registry who were treated with stenting and followed up for 12 months: 1,845 patients who received sirolimus-eluting stents (SES), 1,356 who received paclitaxel-eluting stents (PES), and 365 who received zotarolimus-eluting stents (ZES). CKD was defined as an estimated glomerular filtration rate < 60 mL/min/1.73 m(2) calculated by the modification of diet in renal disease method.

RESULTS

At the 12-month follow-up, patients receiving ZES demonstrated a higher incidence (14.8%) of major adverse cardiac events (MACEs) compared to those receiving SES (10.1%) and PES (12%, p = 0.019). The ZES patients also had a higher incidence (3.9%) of target lesion revascularization (TLR) compared to those receiving SES (1.5%) and PES (2.4%, p = 0.011). After adjusting for confounding factors, ZES was associated with a higher incidence of MACE and TLR than SES (adjusted hazard ratio [HR], 0.623; 95% confidence interval [CI], 0.442 to 0.879; p = 0.007; adjusted HR, 0.350; 95% CI, 0.165 to 0.743; p = 0.006, respectively), and with a higher rate of TLR than PES (adjusted HR, 0.471; 95% CI, 0.223 to 0.997; p = 0.049).

CONCLUSIONS

Our findings suggest that ZES is less effective than SES and PES in terms of 12-month TLR, and has a higher incidence of MACE due to a higher TLR rate compared with SES, in acute MI patients with CKD.

Tamibarotene-loaded citric acid-crosslinked alkali-treated collagen matrix as a coating material for a drug-eluting stent

Tamibarotene-loaded biodegradable matrices with antithrombogenic and drug-releasing properties were prepared in a crosslinking reaction between amino groups of alkali-treated collagen (AlCol) and active ester groups of trisuccinimidyl citrate. The resulting matrices were characterized by their residual amino group concentrations, swelling ratios and thermal, antithrombogenic and drug-releasing properties. It was clarified that the addition of tamibarotene does not inhibit matrix formation. After immersion in water, the swelling ratio of a matrix became lower than that prior to immersion. Thermal analysis indicated that AlCol interacted with tamibarotene. The addition of tamibarotene to the matrix did not influence the antithrombogenic property of the resulting matrix. A matrix with a high crosslinking density had a prolonged tamibarotene elution time. These results demonstrate that tamibarotene-loaded matrices have great potential as a coating material for drug-eluting stents.

Biodegradable versus durable polymer drug eluting stents in coronary artery disease: insights from a meta-analysis of 5,834 patients

BACKGROUND

Biodegradable polymer drug eluting stents (BP-DES) have been developed to overcome the limitations of first generation durable polymer DES (DP-DES) but the clinical results of different BP-DES are not consistent. We performed a meta-analysis to compare the outcomes of BP-DES and DP-DES in the treatment of coronary artery disease (CAD).

METHODS AND RESULTS

Online databases including MEDLINE were searched for studies comparing BP-DES and DP-DES for obstructive CAD that reported rates for overall mortality, myocardial infarction (MI), late stent thrombosis (LST), target lesion revascularization (TLR) and late lumen loss (LLL) with a follow-up of ≥ 6 months. Ten studies (5834 patients) with a 1-year median follow-up were included in the meta-analysis. When comparing patients treated with DP-DES and BP-DES those treated with BP-DES had lower LLL (in-stent: weighted mean difference (WMD) -0.10 mm, 95% CI = -0.17 to -0.03 mm, p = 0.004; in-segment: WMD -0.06 mm, 95% CI = -0.10 to -0.01 mm, p = 0.01) with lower TLR rates (OR 0.67, 95% CI = 0.47 to 0.98, p = 0.04). However, BP-DES did not improve mortality (OR 0.97, 95% CI = 0.73 to 1.29, p = 0.83), MI (OR 1.13, 95% CI = 0.87 to 1.46, p = 0.36) or LST rates (OR 0.64, 95% CI = 0.36 to 1.16, p = 0.14). A pre-specified subgroup analysis of Biolimus BP-DES confirmed significant LLL reduction without differences in other clinical endpoints. Meta-regression analysis demonstrated a strong significant inverse correlation between LLL and reference coronary diameter (p < 0.001).

CONCLUSIONS

Our present meta-analysis showed that BP-DES when compared with DP-DES significantly reduced LLL and TVR but without clear benefits on mortality, MI and LST rates. (Clinicaltrials.gov identifier: NCT01466634).

Zotarolimus-eluting stent versus sirolimus-eluting and paclitaxel-eluting stents for percutaneous coronary intervention: a meta-analysis of randomized trials

BACKGROUND

The zotarolimus-eluting stent (ZES) is a new drug-eluting stent that delivers zotarolimus, a synthetic analogue of sirolimus, through a biocompatible phosphorylcholine polymer coating. ZES has shown promising results compared with bare-metal stents, but its safety and efficacy against sirolimus-eluting (SES) and paclitaxel-eluting (PES) stents is yet to be established.

AIMS

We aimed to summarize current evidence from randomized trials comparing ZES with SES and PES.

METHODS

We searched the Medline, Embase and CENTRAL databases for randomized studies comparing ZES with SES and PES for percutaneous coronary intervention. Relevant clinical and angiographic outcomes were extracted and combined using random and fixed-effect models for heterogeneous and homogenous outcomes, respectively.

RESULTS

Seven randomized trials met the inclusion criteria: ZES group, n=3787; SES group, n=2606; PES group, n=1966. Compared with SES, ZES was associated with significantly higher odds of clinically driven target vessel revascularization (odds ratio [OR] 2.36, 95% confidence interval [CI] 1.78-3.14) and target lesion revascularization (OR 2.46, 95% CI 1.36-4.46). Compared with SES, ZES had higher in-stent restenosis (OR 6.13, 95% CI 3.96-9.50), late lumen loss 'in-stent' (mean difference [MD] 0.39 mm, 95% CI 0.34-0.44) and late lumen loss 'in-segment' (MD 0.18 mm, 95% CI 0.15-0.21). ZES was associated with higher in-stent late lumen loss than PES (MD 0.18 mm, 95% CI 0.07-0.28). There were no differences in mortality, reinfarction or stent thrombosis with ZES compared with SES and PES.

CONCLUSION

ZES is not superior to PES and is inferior to SES in terms of angiographic outcomes and clinically driven revascularization.

Bioactive coatings for coronary stents: Modulation of cell proliferation by controlled release of anti-proliferative drugs

Drug eluting coronary stents coated with a bioactive and biostable polymer system (THBA70), based on acrylate copolymers bearing a salicylic acid derivative as side substituent, were evaluated. The microstructural architecture of the copolymer THBA70 comprises a random copolymer of a methacrylate derivative from triflusal (4-trifluoromethyl salicylic acid) with 45 mol% of THEMA (2-methacryloyloxyethyl [2-(acetyloxy)-4-(trifluoromethyl)] benzoate), which makes the system anti-thrombogenic with good adhesion to the surface of metallic stents. The bioactive coating prevented thrombosis, an adverse effect associated with the implantation of drug-eluting stents. The in vitro drug delivery of drug-eluting stents under dynamic conditions indicated excellent controlled drug release. The THBA70 films loaded with relatively low concentrations of taxol or simvastatin in contact with fibroblasts produced inhibition of cell proliferation with a dose-dependent bioactivity.

Stent thrombosis: an overview

Stent thrombosis is a challenging problem following percutaneous coronary intervention that can lead to serious clinical consequences, such as death and acute myocardial infarction. Its pathophysiology is not yet completely known, and there are several causes suggested, such as incomplete stent endothelization, presence of polymers and late incomplete stent apposition. One of the main predictors is the early discontinuation of dual antiplatelet therapy. Stent improvements related to their design, with more friendly metallic platforms, thinner biocompatible or biodegradable polymers, absence of polymers, and even stents manufactured with bioabsorbable materials, could make the percutaneous procedure much safer and effective, allowing its application in increasingly complex anatomic and clinical scenarios, with low thrombosis rates.

Stent thrombosis and major clinical events at 3 years after zotarolimus-eluting or sirolimus-eluting coronary stent implantation: a randomised, multicentre, open-label, controlled trial

BACKGROUND

We sought to compare the long-term safety of two devices with different antiproliferative properties: the Endeavor zotarolimus-eluting stent (E-ZES; Medtronic, Inc) and the Cypher sirolimus-eluting stent (C-SES; Cordis, Johnson & Johnson) in a broad group of patients and lesions.

METHODS

Between May 21, 2007 and Dec 22, 2008, we recruited 8791 patients from 36 recruiting countries to participate in this open-label, multicentre, randomised, superiority trial. Eligible patients were those aged 18 years or older undergoing elective, unplanned, or emergency procedures in native coronary arteries. Patients were randomly assigned to either receive E-ZES and C-SES (ratio 1:1). Randomisation was stratified per centre with varying block sizes of four, six, or eight patients, and concealed with a central telephone-based or web-based allocation service. The primary outcome was definite or probable stent thrombosis at 3 years and was analysed by intention to treat. Patients and investigators were aware of treatment assignment. This trial is registered with ClinicalTrials.gov, number NCT00476957.

FINDINGS

PROTECT randomised 8791 patients, of whom 8709 provided consent to participate and were eligible: 4357 were allocated to the E-ZES group and 4352 patients to the C-SES group. At 3 years, rates of definite or probable stent thrombosis did not differ between groups (1·4% for E-ZES [predicted: 1·5%] vs 1·8% [predicted: 2·5%] for C-SES; hazard ratio [HR] 0·81, 95% CI 0·58-1·14, p=0·22). Dual antiplatelet therapy was used in 8402 (96%) patients at discharge, 7456 (88%) at 1 year, 3041 (37%) at 2 years, and 2364 (30%) at 3 years.

INTERPRETATION

No evidence of superiority of E-ZES compared with C-SES in definite or probable stent thrombosis rates was noted at 3 years. Time analysis suggests a difference in definite or probable stent thrombosis between groups is emerging over time, and a longer follow-up is therefore needed given the clinical relevance of stent thrombosis.

FUNDING

Medtronic, Inc.