The effect of drug-eluting stents on intermediate angiographic and clinical outcomes in diabetic patients: insights from randomized clinical trials

Diabetes Mellitus and Clinical Outcomes in Carotid Artery Revascularization Using Second-Generation, MicroNet-Covered Stents: Analysis from the PARADIGM Study

INTRODUCTION

Carotid artery stenting (CAS) using conventional (single-layer) stents is associated with worse clinical outcomes in diabetes mellitus (DM) vs. non-DM patients: an effect driven largely by lesion-related adverse events. CAS outcomes with MicroNet-covered stents (MCS) in diabetic patients have not been evaluated.

AIM

To compare short- and long-term clinical outcomes and restenosis rate in DM vs. non-DM patients with carotid stenosis treated using MCS.

MATERIALS AND METHODS

In a prospective study in all-comer symptomatic and increased-stroke-risk asymptomatic carotid stenosis, 101 consecutive patients (age 51-86 years, 41% diabetics) underwent 106 MCS-CAS. Clinical outcomes and duplex ultrasound velocities were assessed periprocedurally and at 30 days/12 months.

RESULTS

Baseline characteristics of DM vs. non-DM patients were similar except for a higher prevalence of recent cerebral symptoms in DM. Type 1 and type 1+2 plaques were more prevalent in DM patients (26.7% vs. 9.8%, p = 0.02; 62.2% vs. 37.7%, p = 0.01). Proximal embolic protection was more prevalent in DM (60% vs. 36%; p = 0.015). 30-day clinical complications were limited to a single periprocedural minor stroke in DM (2.4% vs. 0%, p = 0.22). 12-month in-stent velocities and clinical outcomes were not different (death rate 4.8% vs. 3.3%; p = 0.69; no new strokes). Restenosis rate was not different (0% vs. 1.7%, p = 0.22).

CONCLUSIONS

MCS may offset the adverse impact of DM on periprocedural, 30-day, and 12-month clinical complications of CAS and minimize the risk of in-stent restenosis. In this increased-stroke-risk cohort, adverse event rate was low both in DM and non-DM. Further larger-scale clinical datasets including extended follow-ups are warranted.

Bleeding risk following percutaneous coronary intervention in patients with diabetes prescribed dual anti-platelet therapy

BACKGROUND

Patients with diabetes mellitus (DM) experience higher rates of in-stent restenosis and greater benefit from drug-eluting stents implant at the time of percutaneous coronary intervention (PCI), necessitating prolonged dual anti-platelet therapy (DAPT). While DAPT reduces risk of ischemic events post-PCI, it also increases risk of bleeding. Whether bleeding rates differ among patients with and without DM, receiving long-term DAPT is unknown.

METHODS

Among patients who underwent PCI and were maintained on DAPT for 1 year in a multicenter US registry, we assessed patient-reported bleeding over one year following PCI in patients with and without DM. Multivariable, hierarchical Poisson regression was used to evaluate the association of DM with bleeding during follow-up.

RESULTS

Among 2334 PCI patients from 10 US hospitals (mean age 64, 54% ACS), 32.6% had DM. In unadjusted analyses, patients with DM had fewer bleeding events over the year following PCI (DM vs no DM: BARC = 1: 78.0% vs 87.7%, P < .001; BARC ≥2: 4.3% vs 5.3%, P = .33). Following adjustment, patients with (vs without DM) had a lower risk of BARC ≥1 bleeding during follow-up (relative risk [RR] 0.89, 95% CI 0.83-0.96). This decreased bleeding risk persisted after removing bruising from the endpoint definition.

CONCLUSIONS

In a real-world PCI registry, patients with DM experienced lower risk of bleeding risk on DAPT. As patients with DM also derive greater ischemic benefit from drug-eluting stents, which requires prolonged DAPT, our findings suggest that the balance between benefit and risk of this therapeutic approach may be even more favorable in patients with DM than previously considered.

Cost effectiveness of drug-eluting stents as compared with bare metal stents in patients with coronary artery disease

The aim of this study was to estimate the incremental cost effectiveness of replacing bare metal stents (BMS) by drug-eluting stents (DES) when using trial data and registry data. We developed a Markov model (model of cost effectiveness of coronary artery disease) in which 60-year-old patients started by undergoing percutaneous coronary intervention for acute or subacute coronary artery disease. The patients are followed until death or 100 years of age. Data on the occurrence of events (revascularization, acute myocardial infarction, and death) were based on Scandinavian registry data. Separate analyses were conducted with data on effectiveness based on randomized controlled trials and patient registries. On using trial data, it was found that sirolimus-eluting stents (SES) yield 0.003 greater life expectancy and $3300 lower costs than do BMS (dominant strategy). Paclitaxel-eluting stents (PES) yield 0.148 more life years than do SES at additional lifetime costs of $2800 ($21,400 per life year gained). On using registry data, the cost per life year gained was found to be $4900 when replacing BMS with DES. Probabilistic sensitivity analyses, on the other hand, indicate that PES only has a 50%-75% probability of being cost effective, regardless of the type of effectiveness data. DESs are cost effective with current willingness to pay for life year gains. Whether PES or SES is the most effective DES remains uncertain.

Comparison of drug-eluting and bare-metal stents in patients with diabetes undergoing primary percutaneous coronary intervention: what is the evidence?

A best evidence topic was written according to a structured protocol. The question addressed was, should the practising interventional cardiologist use drug-eluting stents (DESs) or bare-metal stents (BMSs) when undertaking primary percutaneous coronary intervention (PCI) in diabetic patients. The relevant outcomes that were used to determine the answer to this question included: in-stent restenosis, target vessel revascularization (TVR), mortality, myocardial infarction and in-stent thrombosis. The OVID Medline database was used to carry out the reported search for abstracts of relevant journal articles. Altogether 102 papers were found, of which 7 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. From the evidence available, we conclude that in-stent restenosis is less likely to occur over a follow-up of at least 6 months if a DES is used instead of a BMS. Furthermore, TVR is less likely to be required in diabetic patients who receive a DES in comparison with a BMS. Nevertheless, no significant difference in mortality between stents was detected by the studies reviewed. This included no difference in the incidence of cardiac and non-cardiac causes of death. There was evidence showing that DESs are associated with a decrease in the risk of myocardial infarction and, in particular, a decrease in non-Q-wave myocardial infarction. However, there was also conflicting evidence demonstrating no significant difference in the incidence of myocardial infarction between diabetic patients who had received a BMS or a DES. Moreover, the available evidence showed no significant difference in the risk of in-stent thrombosis for all DESs with the exception of Sirolimus eluting stents in which the evidence was not consistent. In summary, the available evidence supports the use of DESs over BMSs in diabetic patients undergoing primary PCI.

The favorable price evolution between bare metal stents and drug eluting stents increases the cost effectiveness of drug eluting stents

AIMS

We aimed to assess the cost effectiveness of the sirolimus-eluting stent (SES) in diabetic and non-diabetic patients vs. bare metal stents (BMS).

METHODS

EVASTENT was a matched cohort registry of patients undergoing revascularization exclusively with SES; for each diabetic patient (db+) included, stratified according to single (SVD) or multiple (MVD) vessel disease, a non-diabetic patient (db-) was subsequently included. Efficacy, safety and cost data were obtained from the SES database, and then data from the BMS group were derived by using an original method of transition probabilities of events (Markov model and Monte Carlo simulations) if BMS had been implanted in the same patient, over a 3-year time period. Sensitivity analysis was performed by varying the price difference between BMS and SES from 2008 to 2012.

RESULTS

In this study, 1731 patients were included with 97% complete follow-up at 3-years. In 2008, compared to BMS the SES was cost effective only in MVD db+ (7494€ per avoided revascularization (PAR) vs. >10,000€ in other groups). In 2012, after a reduction in the price difference between SES and BMS, SES were cost effective in MVD db+ (-891), SVD db+ (3519), MVD db- (3050), and SVD db- (6329) patients. Otherwise, the cardiovascular mortality rate was higher (p<0.0001) in MVD db+ than in SVD db+, MVD db- and SVD db-.

CONCLUSION

The SES is now cost effective in diabetic and non-diabetic patients, after a favorable price evolution between drug eluting and bare metal stents.

Differences in drug-eluting stents used in coronary artery disease

The introduction of drug-eluting stents (DES) has improved the efficacy of percutaneous coronary intervention by addressing the issue of neointimal proliferation, a pathology contributing to restenosis. First-generation stents eluting sirolimus or paclitaxel were joined by second-generation stents, such as the everolimus- and the zotarolimus-eluting stents, promising increased safety and efficacy. As a result, there is a plethora of drug-eluting stents available, with differences in the stent platform, the polymer coating and the eluted drug, which translate into differences in biological markers of efficacy, such as late loss. However, it remains controversial whether these discrepancies have an impact on clinical markers of safety and efficacy, or if the improved efficacy of DES is a class effect. This article reviews the differences between DES by looking into the biological differences and into trials and registries of DES.

A meta-analysis of specifically designed randomized trials of sirolimus-eluting versus paclitaxel-eluting stents in diabetic patients with coronary artery disease

BACKGROUND

There is an ongoing debate on the optimal drug-eluting stent (DES) in diabetic patients with coronary artery disease. We addressed this issue by making a synthesis of the available evidence on the relative long-term efficacy and safety of sirolimus-eluting stent (SES) and paclitaxel-eluting stent (PES) in these patients.

METHODS

Individual patient data were analyzed from 6 randomized trials specifically designed to compare SES with PES in diabetic patients. In total, 1183 patients were followed up for a median of 3.9 years (25th, 75th percentiles 3.4-4.5 years). The primary efficacy end point was target lesion revascularization (TLR). The composite of death and myocardial infarction (MI) was the primary safety end point. Stent thrombosis was a secondary end point. Overall hazard ratios (HRs) with 95% CIs were calculated as summary estimates.

RESULTS

No significant heterogeneity was seen across the 6 randomized trials for all analyzed events. Sirolimus-eluting stent was associated with a significant reduction in the risk of TLR (HR 0.65 [0.47-0.91], P = .01). No significant differences were observed regarding the risk of death or MI (HR 1.04 [0.74-1.45], P = .83) and stent thrombosis (HR 1.00 [0.31-3.30], P = .67). Mortality was also not affected by the type of DES (HR 0.95 [0.65-1.39], P = .79).

CONCLUSIONS

In diabetic patients with coronary artery disease, SES leads to a sustained reduction in the risk of TLR compared with PES. Both these DES types are, however, comparable with respect to the risk of stent thrombosis, MI, or death over long-term follow-up.

A dual-inhibition study on vascular smooth muscle cells with meclofenamic acid and β-irradiation for the prevention of restenosis

PURPOSE

Restenosis is still one of the major limitations after angioplasty. A therapeutic treatment combining β-irradiation and pharmacologic cyclooxygenase-2 inhibition was employed to study the impact on vascular smooth muscle cells (SMCs).

MATERIALS AND METHODS

The effects of meclofenamic acid in combination with yttrium-90 ((90)Y) on cell growth, clonogenic activity, cell migration, and cell cycle distribution of human aortic SMCs were investigated. Treatment was sustained over a period of 4 days and recovery of cells was determined until day 20 after initiation. The hypothesis was that there is no difference between control and treated groups.

RESULTS

A dose-dependent growth inhibition was observed in single and combined treatment groups for meclofenamic acid and β-irradiation. Cumulative radiation dosage of 8 Gy completely inhibited colony formation. This was also observed for 200 μM meclofenamic acid alone or in combination with minor β-irradiation dosages. Results of the migration tests showed also a dose dependency with additive effects of combined therapy. Meclofenamic acid 200 μM alone and with cumulative β-irradiation dosages resulted in an increased G2/M-phase share.

CONCLUSIONS

Incubating human SMCs with meclofenamic acid and (90)Y for a period of 4 d (ie, 1.5 half-life times) resulted in an effective inhibition of smooth muscle cell proliferation, colony formation, and migration.

Impact of insulin-treated diabetes and hemodialysis on long-term clinical outcomes following sirolimus-eluting stent deployment. Insights from a sub-study of the Cypher Stent Japan Post-Marketing Surveillance(Cypher J-PMS) Registry

BACKGROUND

Long-term clinical outcomes of diabetes mellitus (DM) patients who underwent drug-eluting stent deployment has not well investigated.

METHODS AND RESULTS

A total of 2,050 cases were enrolled consecutively from 50 sites in Japan into the Cypher stent Japan Post-Marketing Surveillance (Cypher J-PMS) registry, and the 3-year outcomes of DM patients were analyzed. Subjects were divided into 2 groups based on the treatment of DM (insulin-treated diabetes (IT) group, n=207; and non insulin-treated diabetes (NIT) group, n=682). Major adverse cardiac event (MACE) rates in the IT group and the NIT group were 26.0% and 14.5% at 3 years, respectively (P<0.001). There were no significant differences in stent thrombosis rates (definite and probable by Academic Research Consortium (ARC) definition) (0% and 1.08%, respectively). Multivariate analysis suggested that hemodialysis and insulin-treated DM were independent predictors for MACE, and insulin-treated DM, hemodialysis and long lesions were strong independent predictors for target-lesion revascularization (TLR).

CONCLUSIONS

Hemodialysis and insulin-treated DM were strong independent predictors of mortality and TLR in DM patients. These results might suggest that special attention to patients with hemodialysis and insulin-treated DM is warranted in the setting of sirolimus-eluting stent deployment for DM patients.

Long-term vascular changes after drug-eluting stent implantation assessed by serial volumetric intravascular ultrasound analysis

Using serial volumetric intravascular ultrasonography, we evaluated the predictors of late intimal hyperplasia (IH) increases after drug-eluting stent implantation. All eligible patients who underwent 6-month angiography without visual restenosis were requested to undergo a 2-year follow-up examination. Complete serial (after stenting and early [6-month], and late [2-year] follow-up) angiographic and intravascular ultrasound data were available for 135 patients with 143 lesions: 99 sirolimus-eluting stents and 44 paclitaxel-eluting stents. The external elastic membrane, stent, lumen, and peri-stent plaque volumes (external elastic membrane minus stent) were normalized by stent length. The percentage of IH volume was calculated as IH volume/stent volume x 100. The early reduction in the minimum lumen area was greater than the late reduction in the minimum lumen area (-0.8 +/- 0.8 vs -0.2 +/- 0.5 mm(2), p <0.001). A progressive increase occurred in the percentage of IH volume: 8.1 +/- 7.1% from baseline to 6 months and 2.4 +/- 3.9% from 6 months to 2 years (p <0.001, between the early and late increases in the percentage of IH). The use of paclitaxel-eluting stents was the only independent predictor for the percentage of IH volume at 6 months (beta = 0.419, p <0.001). The use of paclitaxel-eluting stents (beta = 0.365, p <0.001, 95% confidence interval 3.7 to 9.7) and the post-stenting normalized plaque and media volume (beta = 0.195, p = 0.020, 95% confidence interval 0.1 to 1.6) were the only independent predictors for the percentage of IH volume at 2 years. However, when the percentage of IH at 6 months was forced into the model, the percentage of IH at 6 months and the post-stenting normalized plaque and media volume, not paclitaxel-eluting stent use, predicted the 2-year percentage of IH. In conclusion, although IH continued to increase beyond 6 months, the growth rate of intima and luminal loss attenuated with time.

Meta-analysis of five randomized clinical trials comparing sirolimus- versus paclitaxel-eluting stents in patients with diabetes mellitus

Recent data on drug-eluting stents have shown improved clinical outcomes in patients with diabetes mellitus. However, the relative efficacy and safety of sirolimus-eluting stents (SES) compared with paclitaxel-eluting stents (PES) remains controversial. Therefore, a meta-analysis of randomized trials was performed to compare SES with PES exclusively in patients with diabetes. The published research was scanned by formal searches of electronic databases (PubMed, EMBASE and the Cochrane Central Register of Controlled Trials) from January 2001 to April 2009. All randomized trials involving head-to-head comparison of SES versus PES in patients with diabetes were examined for analysis. A total of 5 randomized trials were included in the present meta-analysis, involving 1,173 patients (594 in the SES group, 579 in the PES group). SES were significantly more effective in the reduction of target lesion revascularization (5.1% vs 11.4%, odds ratio [OR] 0.41, 95% confidence interval [CI] 0.26 to 0.64, p <0.001) and angiographic binary (> or =50%) restenosis (5.6% vs 16.4%, OR 0.30, 95% CI 0.19 to 0.48, p <0.001) compared to PES. In contrast, the differences between SES and PES were not statistically significant with respect to cardiac death (2.2% vs 2.9%, OR 0.71, 95% CI 0.34 to 1.47, p = 0.35), myocardial infarction (1.5% vs 2.6%, OR 0.58, 95% CI 0.26 to 1.31, p = 0.19), and stent thrombosis (0.6% vs 1.2%, OR 0.57, 95% CI 0.18 to 0.84, p = 0.35). In conclusion, SES are superior to PES in reducing the incidences of restenosis and target lesion revascularization in patients with diabetes, with nonsignificant differences in terms of cardiac death, myocardial infarction, and stent thrombosis.

Comprehensive meta-analysis on drug-eluting stents versus bare-metal stents during extended follow-up

BACKGROUND

Several observational reports have documented both increased and decreased cardiac mortality or Q-wave myocardial infarction with drug-eluting stents compared with bare-metal stents.

METHODS

We sought to evaluate the safety and efficacy of drug-eluting stents compared with bare-metal stents early after intervention (<1 year) and late (>1 year) among a broad population of patients, using a meta-analysis of randomized clinical trials.

RESULTS

We identified 28 trials with a total of 10,727 patients and a mean follow-up of 29.6 months. For early outcomes (<1 year), all-cause mortality for drug-eluting stents versus bare-metal stents was 2.1% versus 2.4% (risk ratio [RR] 0.91, [95% confidence interval (CI), 0.70-1.18]; P=.47), non-Q-wave myocardial infarction was 3.3% versus 4.4% (RR 0.78 [95% CI, 0.61-1.00]; P=.055), target lesion revascularization was 5.8% versus 18.4% (RR 0.28 [95% CI, 0.21-0.38]; P <.001), and stent thrombosis was 1.1% versus 1.3% (RR 0.87 [95% CI, 0.60-1.26]; P=.47). For late outcomes (>1 year), all-cause mortality for drug-eluting stents versus bare-metal stents was 5.9% versus 5.7% (RR 1.03 [95% CI, 0.83-1.28]; P=.79), target lesion revascularization was 4.0% versus 3.3% (RR 1.22 [95% CI, 0.92-1.60]; P=.16), non-Q-wave myocardial infarction was 1.6% versus 1.2% (RR 1.36 [95% CI, 0.74-2.53]; P=.32) and stent thrombosis was 0.7% versus 0.1% (RR 4.57 [95% CI, 1.54-13.57]; P=.006).

CONCLUSIONS

There was no excess mortality with drug-eluting stents. Within 1 year, drug-eluting stents appear to be safe and efficacious with possibly decreased non-Q-wave myocardial infarction compared with bare-metal stents. After 1 year, drug-eluting stents still have similar mortality, despite increased stent thrombosis. The reduction in target lesion revascularization with drug-eluting stents mainly happens within 1 year, but is sustained thereafter.

Diabetes mellitus: a prothrombotic state implications for outcomes after coronary revascularization

Coronary stent thrombosis is a serious problem in the drug-eluting stent era. Despite aggressive antiplatelet therapy during and after percutaneous coronary intervention (PCI), the incidence of sub-acute stent thrombosis remains approximately 0.5%–2%, which may represent a catastrophic clinical situation. Both procedural factors and discontinuation of antiplatelet therapy are normally associated with this event. We report on simultaneous stent thromboses of two drug-eluting stents implanted in two different vessels, which resulted in a life-threatening clinical condition. Possible contributing factors that led to synergistic thrombotic effects are discussed.

Drug-eluting stents: a comprehensive appraisal

Cardiovascular medicine has evolved over the last few decades, with the advent of percutaneous interventional treatments. In particular, balloon angioplasty and, subsequently, coronary stenting has revolutionized our current perspective of stable and unstable coronary artery disease management. However, the long-term results of stent usage have been blighted by the dual problems of in-stent restenosis and stent thrombosis. Whilst stent thrombosis became much less frequent with the introduction of dual-antiplatelet therapy, restenosis remained a significant problem. Intense work on stent development has successfully led to the introduction of drug-eluting stents (DES) in an effort to address this problem. Randomized trials have consistently proven the superior efficacy of DES over bare metal stents, in elective patients, acute coronary syndromes and patients with diabetes mellitus. Nevertheless, the routine use of DES in by-pass venous graft disease remains debatable. The initial DES used sirolimus and paclitaxel are now being joined by newer stents releasing drugs, such as everolimus, zotarolimus and tacrolimus. Ongoing developments with the stent platform and the polymer coating are also gradually improving the performance of these stents in clinical practice. More recently, the idea of antibody-coated stents that would encourage epithelialization of stent struts by endothelial progenitor cells recruitment has gained attraction among interventionists, with a possible beneficial impact on reducing the incidence of restenosis.

Hopes, disillusions and more hopes from vitamin C

In the current view of most biochemists and physiologists, the role of L-ascorbic acid (AA) in cell metabolism would be more or less confined to the scavenging of reactive oxygen species. Nevertheless, many data have been collected in our and other laboratories concerning the involvement of AA in many different aspects of cell metabolism. At the present time the molecular sites of action of AA have not been completely elucidated, but recent findings on the specific requirement of AA for the activity of several 2-oxoacid-dependent dioxygenases involved in cell signalling and the activation of transcription factors open new fascinating perspectives for further research.