Journal of comparative effectiveness research
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Review Comparative Study
Drug-eluting versus bare-metal coronary stents: where are we now?
Drug-eluting stents have dramatically reduced the risk of restenosis, but concerns of an increased risk of stent thrombosis have provided uncertainty about their use. Recent studies have continued to show improved procedural and clinical outcomes with drug-eluting stents both in the setting of acute coronary syndromes and stable coronary artery disease. Newer generation drug-eluting stents (especially everolimus-eluting stents) have been shown to be not only efficacious but also safe with reduced risk of stent thrombosis when compared with bare-metal stents, potentially changing the benchmark for stent safety from bare-metal stents to everolimus-eluting stents. While much progress is being made in the development of bioabsorbable polymer stents, nonpolymer stents and bioabsorbable stent technology, it remains to be seen whether these stents will have superior safety and efficacy outcomes compared with the already much improved rates of revascularization and stent thrombosis seen with newer generation stents (everolimus-eluting stents and resolute zotarolimus-eluting stents).
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Clinical trials have largely focused on whether an intervention can work. To ensure valid and powerful testing of this hypothesis, trials attempt to maximize the effect of the intervention of interest, controlling other factors that can confound comparisons. ⋯ Minimizing biases in this pragmatic context remains a very difficult task, however. This paper reviews some of these challenges and highlights specific aspects of design that must be approached with a pragmatic attitude.
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Intravenous thrombolysis with alteplase is one of the few evidence-based acute ischemic stroke treatments. Efficacy is time dependent and not all patients treated within the 4.5 h license derive benefit. ⋯ In the Phase II study by Parsons and colleagues, tenecteplase was superior to alteplase across imaging and safety outcomes for patients selected using specific imaging criteria. We review the evidence for thrombolysis, experience with tenecteplase and compare this study with others that have used similar designs for the investigation of novel stroke lytic agents.