Meta-analysis comparing the effect of drug-eluting versus bare metal stents on risk of acute myocardial infarction during follow-up

In-stent restenosis of drug-eluting stents

Drug-eluting stents (DES) have emerged as an improved alternative to bare-metal stents by demonstrating reduced rates of restenosis and target lesion revascularization. This emergence has led to the unrestricted use of DES for various indications and lesions, and subsequently revealed DES in-stent restenosis as a novel interventional therapeutic dilemma. Recent insights regarding the patho-physiological processes and therapeutic alternatives have added to the accumulated knowledge regarding the appropriate approach to this phenomenon. This review aims to detail the mechanism and clinical presentation of, and therapeutic strategies for, the treatment of DES in in-stent restenosis.

Periprocedural (30-day) risk of myocardial infarction after drug-eluting coronary stent implantation: a meta-analysis comparing cobalt-chromium and stainless steel drug-eluting coronary stents

AIMS

Because of the reduction in the rate events related with in-stent restenosis, most events after drug-eluting stent implantation occur shortly after coronary stenting. Cobalt-chromium alloys allow to reduce strut thickness and improve flexibility and deliverability of coronary stent platforms, and thus could be associated with lower short-term events after stenting. The aim of this study was to test the hypothesis that drug-eluting coronary stents with a cobalt-chromium platform reduce the incidence of periprocedural (30-day) myocardial infarction in comparison with stainless steel drug-eluting coronary stents.

METHODS AND RESULTS

A meta-analysis from nine randomised trials comparing cobalt-chromium and stainless steel drug-eluting coronary stents that overall included 11,313 patients was performed. The incidence of myocardial infarction, stent thrombosis, and cardiac death at 30 days was compared between both types of stents. At 30 days, the incidence of acute myocardial infarction was significantly lower in patients allocated to cobalt-chromium drug-eluting stents (2.3% vs. 3.9%, respectively; p=0.006; odds ratio 0.72, 95% confidence interval 0.58-0.91), due to a significant reduction in the rate of non-Q-wave myocardial infarction (odds ratio 0.67, 95% confidence interval 0.51-0.88). The incidence of stent thrombosis was similar between both groups of patients, (0.5% vs. 0.5%, p=0.76; odds ratio 1.09, 95% confidence interval 0.63-1.89).

CONCLUSIONS

Drug-eluting coronary stents that use cobalt-chromium stent platforms have a better safety profile at 30 days in comparison with stainless steel drug-eluting stents, due to a significant reduction in the rate of myocardial infarction.

Drug-eluting stents versus bare-metal stents in acute myocardial infarction: A systematic review and meta-analysis

Objectives: Recent concerns have been raised for the safety after drug-eluting stents (DES) implantation compared with the use of bare-metal stents (BMS) in patients with ST-elevation acute myocardial infarction (STEMI). The objective of this study was to estimate the relative impact of DES versus BMS on mortality, myocardial infarction (MI), target vessel revascularization (TVR), and stent thrombosis (ST) in STEMI patients by performing comprehensive meta-analyses of randomized controlled trials (RCTs) and observational studies.

Methods: We performed an electronic search and manual search of studies presented through September 2009, without language restrictions. An approach of “using systematic reviews” was used. Two independent reviewers extracted prespecified data from each study. A random-effects model was used to combine trials and to perform stratified analyses based on study designs and the duration of follow-up.

Results: Fourteen RCTs were identified (N = 7,654). Compared with BMS, DES significantly reduced TVR (risk ratio [RR], 0.48; 95 percent confidence interval [CI], 0.41–0.56) and MI (RR, 0.77; 95 percent CI, 0.61–0.97), without increasing mortality (RR, 0.88; 95 percent CI, 0.70–1.10) and ST (RR, 0.93; 95 percent CI, 0.72–1.21). Among 35 observational studies (N = 44,849), the use of DES was associated with a significant reduction in mortality (RR, 0.85; 95 percent CI, 0.79–0.91) and TVR (RR, 0.61; 95 percent CI, 0.48–0.77). MI and ST were significantly lower in the DES group within 1-year follow-up, but there were no differences within 2 years of follow-up. There was no evidence of statistical heterogeneity and publication bias.

Conclusions: These data in aggregate suggest that using DES in STEMI patients is safe and efficacious, but there are differences between RCT and observational data comparing DES and BMS.

Determining clinical benefits of drug-eluting coronary stents according to the population risk profile: a meta-regression from 31 randomized trials

BACKGROUND

The use of drug-eluting stents (DES) in unfavourable patients has been associated with higher rates of clinical complications and stent thrombosis, and because of that concerns about the use of DES in high-risk settings have been raised.

OBJECTIVE

This study sought to demonstrate that the clinical benefit of DES increases as the risk profile of the patients increases.

METHODS

A meta-regression analysis from 31 randomized trials that compared DES and bare-metal stents, including overall 12,035 patients, was performed. The relationship between the clinical benefit of using DES (number of patients to treat [NNT] to prevent one episode of target lesion revascularization [TLR]), and the risk profile of the population (rate of TLR in patients allocated to bare-metal stents) in each trial was evaluated.

RESULTS

The clinical benefit of DES increased as the risk profile of each study population increased: NNT for TLR=31.1-1.2 (TLR for bare-metal stents); p<0.001. The use of DES was safe regardless of the risk profile of each study population, since the effect of DES in mortality, myocardial infarction, and stent thrombosis, was not adversely affected by the risk profile of each study population (95% confidence interval for β value 0.09 to 0.11, -0.12 to 0.19, and -0.03 to-0.15 for mortality, myocardial infarction, and stent thrombosis, respectively).

CONCLUSIONS

The clinical benefit of DES increases as the risk profile of the patients increases, without affecting safety.

Meta-analysis comparison (nine trials) of outcomes with drug-eluting stents versus bare metal stents in patients with diabetes mellitus

In patients with diabetes mellitus, outcome after drug-eluting stent (DES) versus bare metal stent (BMS) implantation remains under investigation; although lower reintervention rates were reported, incidence of death and myocardial infarction (MI) during follow-up is not completely characterized. Thus, we performed a meta-analysis of available randomized studies evaluating follow-up events of DESs versus BMSs in patients with diabetes mellitus. Randomized trials reporting outcome of DES versus BMS in diabetic patients with a follow-up > or =6 months were included. Outcomes analyzed were (1) death, (2) MI, (3) in-stent restenosis (ISR) and target lesion revascularization (TLR), and (4) stent thrombosis. Data were extracted by 2 independent reviewers. A total of 9 trials, including 1,141 patients, were found. ISR occurred in 8% of patients with DESs versus 41% of those with BMSs (odds ratio [OR] 0.13, 95 confidence interval [CI] 0.09 to 0.20, p <0.00001) and TLR in 8% versus 27% (OR 0.23, 95% CI 0.16 to 0.33, p <0.00001). There was no difference in the incidence of stent thrombosis (1.1% vs 1.2%, p = 0.98) or death (2.4% vs 2.3%, p = 0.91). MI occurred in 3.5% of patients with DESs versus 7.2% of those with BMSs (52% risk decrease, p = 0.02). Decrease of ISR with DESs was observed in noninsulin-treated (OR 0.17, 95% CI 0.11 to 0.26, p <0.00001) and insulin-treated (OR 0.22, 95% CI 0.13 to 0.37, p <0.00001) patients. In conclusion, diabetic patients receiving DESs have lower risk of ISR and TLR versus those treated with BMSs; use of DESs in patients with diabetes mellitus significantly decreases the incidence of MI during follow-up, without affecting mortality or stent thrombosis.

Effect of thiazolidinediones on in-stent restenosis in patients after coronary stenting: a meta-analysis of randomized controlled trials

BACKGROUND

Recent experimental studies have demonstrated that thiazolidinediones (TZDs) therapy inhibits proliferation and migration of vascular smooth muscle cells, accelerates endothelium reparation and attenuates neointimal hyperplasia. It implies that TZDs therapy may have beneficial effects on in-stent restenosis (ISR). Several small-sample clinical trials have evaluated the effect of TZDs therapy on ISR, however, the results were inconsistent across trials.

METHODS AND RESULTS

We performed a meta-analysis of all relevant randomized controlled trials to evaluate the effect of TZDs therapy on in-stent restenosis in patients undergoing coronary stenting. Eight trials involving 366 patients were included in this study. TZDs therapy was associated with a significant reduction in the risk of ISR in both diabetic (RR 0.37, 95% CI 0.23-0.59; P<0.0001) and non-diabetic patients (RR 0.16, 95% CI 0.05-0.45; P=0.0006). TZDs therapy was associated with a significant reduction in late lumen loss (WMD -0.54 mm, 95% CI -0.87 mm, -0.22 mm; P=0.001), percent diameter stenosis (WMD -15.7%, 95% CI -19.4%, -12.0%; P<0.00001), neointimal area/volume (SMD -0.76, 95% CI -1.13, -0.39; P<0.0001) and target lesion revascularization (RR 0.32, 95% CI 0.18-0.57; P=0.0001).

CONCLUSIONS

Our study suggests that TZDs therapy is an effective strategy in preventing ISR in both diabetic and non-diabetic patients undergoing coronary stenting. More studies, especially large multi-centre RCTs, are still warranted to further clarify the anti-restenotic effect of TZDs therapy.

Late angiographic stent thrombosis: the LAST straw for drug-eluting stents?

The long-term patency advantage of drug-eluting stents represents a quantum leap in the percutaneous treatment of ischemic heart disease. Although initial landmark trials demonstrated equivalent safety to bare-metal stents, subsequent follow-up analyses have suggested a slight late thrombotic risk. This widely publicized issue poses major public health implications for the medical and lay communities. However, available data indicate that this late risk is counterbalanced by the dramatic drug-eluting stent reduction in target lesion revascularizations, resulting in equivalent overall major adverse cardiovascular event rates than that of the bare-metal stents The recent Food and Drug Administration's guidelines regarding these devices are delineated in detail. Specifically, compliance with dual antiplatelet therapy (minimum 1 year) is of paramount consideration in patient selection for drug-eluting stents. Moreover, when deployed for "on-label" indications, they provide significant restenosis advantage, with a slight late thrombotic risk but without overall increase in death or infarction.

Making sense of the recent meta-analytical confusion concerning the safety of drug-eluting stents

The safety of drug-eluting stents (DES) in patients undergoing percutaneous coronary intervention has been questioned in several independent meta-analyses (i.e., systematic reviews of primary research studies employing statistical methods to provide pooled estimates) published or presented at the end of 2006. Other reviews and meta-analyses have followed in the beginning of 2007, albeit with unclear or conflicting results. This article provides a succinct perspective and critical appraisal of recently published meta-analyses focusing on DES safety, summarising key features and findings of each work, and recommending avenues for further research and practice.