Randomized comparison of cost-saving and effectiveness of oral rapamycin plus bare-metal stents with drug-eluting stents: three-year outcome from the randomized oral rapamycin in Argentina (ORAR) III trial

Macrophages in cardiovascular diseases: molecular mechanisms and therapeutic targets

The immune response holds a pivotal role in cardiovascular disease development. As multifunctional cells of the innate immune system, macrophages play an essential role in initial inflammatory response that occurs following cardiovascular injury, thereby inducing subsequent damage while also facilitating recovery. Meanwhile, the diverse phenotypes and phenotypic alterations of macrophages strongly associate with distinct types and severity of cardiovascular diseases, including coronary heart disease, valvular disease, myocarditis, cardiomyopathy, heart failure, atherosclerosis and aneurysm, which underscores the importance of investigating macrophage regulatory mechanisms within the context of specific diseases. Besides, recent strides in single-cell sequencing technologies have revealed macrophage heterogeneity, cell-cell interactions, and downstream mechanisms of therapeutic targets at a higher resolution, which brings new perspectives into macrophage-mediated mechanisms and potential therapeutic targets in cardiovascular diseases. Remarkably, myocardial fibrosis, a prevalent characteristic in most cardiac diseases, remains a formidable clinical challenge, necessitating a profound investigation into the impact of macrophages on myocardial fibrosis within the context of cardiac diseases. In this review, we systematically summarize the diverse phenotypic and functional plasticity of macrophages in regulatory mechanisms of cardiovascular diseases and unprecedented insights introduced by single-cell sequencing technologies, with a focus on different causes and characteristics of diseases, especially the relationship between inflammation and fibrosis in cardiac diseases (myocardial infarction, pressure overload, myocarditis, dilated cardiomyopathy, diabetic cardiomyopathy and cardiac aging) and the relationship between inflammation and vascular injury in vascular diseases (atherosclerosis and aneurysm). Finally, we also highlight the preclinical/clinical macrophage targeting strategies and translational implications.

Potential therapeutic effects of mTOR inhibition in atherosclerosis

Despite significant improvement in the management of atherosclerosis, this slowly progressing disease continues to affect countless patients around the world. Recently, the mechanistic target of rapamycin (mTOR) has been identified as a pre-eminent factor in the development of atherosclerosis. mTOR is a constitutively active kinase found in two different multiprotein complexes, mTORC1 and mTORC2. Pharmacological interventions with a class of macrolide immunosuppressive drugs, called rapalogs, have shown undeniable evidence of the value of mTORC1 inhibition to prevent the development of atherosclerotic plaques in several animal models. Rapalog-eluting stents have also shown extraordinary results in humans, even though the exact mechanism for this anti-atherosclerotic effect remains elusive. Unfortunately, rapalogs are known to trigger diverse undesirable effects owing to mTORC1 resistance or mTORC2 inhibition. These adverse effects include dyslipidaemia and insulin resistance, both known triggers of atherosclerosis. Several strategies, such as combination therapy with statins and metformin, have been suggested to oppose rapalog-mediated adverse effects. Statins and metformin are known to inhibit mTORC1 indirectly via 5' adenosine monophosphate-activated protein kinase (AMPK) activation and may hold the key to exploit the full potential of mTORC1 inhibition in the treatment of atherosclerosis. Intermittent regimens and dose reduction have also been proposed to improve rapalog's mTORC1 selectivity, thereby reducing mTORC2-related side effects.

WITHDRAWN: Drug-eluting stents versus bare metal stents for angina or acute coronary syndromes

This review 'topic' has been included in work being carried out as part of a Health Technology Assessment commissioned by the National Institute for Clinical Excellence in England and Wales. Details of this research is available via www.nice.org.uk.

The views and opinions expressed herein are those of the authors and do not necessarily reflect those of the HTA programme, NICE, NIHR, NHS or the Department of Health.

The review has been split into 2 reviews that will be published as "Drug‐eluting stents versus bare‐metal stents for stable ischaemic heart disease" and "Drug‐eluting stents versus bare‐metal stents for acute coronary syndrome".

The editorial group responsible for this previously published document have withdrawn it from publication.

Comparison of cost-effectiveness of oral rapamycin plus bare-metal stents versus first generation of drug-eluting stents (from the Randomized Oral Rapamycin in Argentina [ORAR] 3 trial)

The aim of this study was to compare 5-year cost-effectiveness and clinical outcomes of patients with oral rapamycin (OR) plus bare-metal stent versus the drug-eluting stent (DES) strategy. During 2006 to 2007, a total of 200 patients were randomized to OR (n = 100) and DES (n = 100). Primary end point was to compare costs of initial procedure and cost-effectiveness of both revascularization strategies. Safety was evaluated by the composite of death, myocardial infarction, and cerebrovascular accident. Efficacy was assessed by target vessel and target lesion revascularizations. The 2 groups had similar baseline demographic, clinical, and angiographic characteristics. In the DES group, paclitaxel-, zotarolimus-, and sirolimus-eluting stents were used. Five-year clinical follow-up was accomplished in 99% patients. The DES group had significantly higher procedural (p <0.001), discharge to first-year (p = 0.02), and 1- to 5-year costs (p <0.001) compared with the OR group. At 5 years, the composite end point of death, myocardial infarction, and cerebrovascular accident (12% in the OR group vs 25% in the DES group, p = 0.01) was significantly less in the OR group. Target vessel revascularization (14.5% in the OR group vs 21% in the DES group, p = 0.16) and target lesion revascularization (10% in the OR group vs 17.6% in the DES group, p = 0.05) were not significantly different. In conclusion, a strategy of OR plus bare-metal stent was cost saving than a first-generation DES.

mTOR inhibition: a promising strategy for stabilization of atherosclerotic plaques

Statins are currently able to stabilize atherosclerotic plaques by lowering plasma cholesterol and pleiotropic effects, but a residual risk for atherosclerotic disease remains. Therefore, effective prevention of atherosclerosis and treatment of its complications is still a major clinical challenge. A large body of evidence indicates that mammalian target of rapamycin (mTOR) inhibitors such as rapamycin or everolimus have pleiotropic anti-atherosclerotic effects so that these drugs can be used as add-on therapy to prevent or delay the pathogenesis of atherosclerosis. Moreover, bioresorbable scaffolds eluting everolimus trigger a healing process in the vessel wall, both in pigs and humans, that results in late lumen enlargement and plaque regression. At present, this phenomenon of atheroregression is poorly understood. However, given that mTOR inhibitors suppress cell proliferation and trigger autophagy, a cellular survival pathway and a process linked to cholesterol efflux, we hypothesize that these compounds can inhibit (or reverse) the basic mechanisms that control plaque growth and destabilization. Unfortunately, adverse effects associated with mTOR inhibitors such as dyslipidemia and hyperglycemia have recently been identified. Dyslipidemia is manageable via statin treatment, while the anti-diabetic drug metformin would prevent hyperglycemia. Because metformin has beneficial macrovascular effects, this drug in combination with an mTOR inhibitor might have significant promise to treat patients with unstable plaques. Moreover, both statins and metformin are known to inhibit mTOR via AMPK activation so that they would fully exploit the beneficial effects of mTOR inhibition in atherosclerosis.

Systematic review of effectiveness of oral sirolimus after bare-metal stenting of coronary arteries for prevention of in-stent restenosis

Neointimal hyperplasia after percutaneous coronary intervention is a major determinant of in-stent restenosis (ISR). Drug-eluting stents (DES) mitigate neointimal hyperplasia and thereby lead to a lower rate of ISR compared with bare-metal stents (BMS). Recent studies have demonstrated that short-term use of oral sirolimus after BMS leads to a significant reduction in ISR. We therefore sought to do a systematic review of studies to determine the angiographic and clinical benefits of early short-term use of oral sirolimus after BMS of native coronary arteries. We conducted PubMed, Embase, Cochrane database review, and Web of Science search of studies comparing oral sirolimus after BMS to BMS alone or DES. Outcomes analyzed were ISR and target lesion revascularization (TLR) as well as major adverse cardiovascular events. A total of 488 patients from 4 studies were included in the review (2006 to 2010). Three studies, comparing BMS alone versus BMS plus oral sirolimus, demonstrated significant reduction in ISR in the oral sirolimus group. Two of these studies also demonstrated significant reduction in TLR at 6-12 month follow-up. The fourth study comparing BMS plus oral sirolimus versus DES showed a lower but nonsignificant reduction in TLR in addition to significant cost saving in the group treated with oral sirolimus. In conclusion, our systematic review demonstrates that early short-term systemic use of sirolimus after BMS resulted in a significant reduction in ISR and TLR. In addition, ISR rates were comparable to DES with the added benefit of cost saving.

Changes in the safety paradigm with percutaneous coronary interventions in the modern era: Lessons learned from the ASCERT registry

In the past, comparative effectiveness trials evaluating percutaneous coronary interventions (PCI), using either balloon angioplasty or bare metal stent (BMS) implantation, versus coronary artery bypass surgery (CABG) found similar survival rates at long-term follow-up with both revascularization strategies. Two major meta-analyses of these trials reported 5- and 6-year comparative effectiveness between PCI and CABG: one included only four trials that compared PCI with BMS implantation versus CABG whereas the largest one also included trials using balloon angioplasty. In these studies, the authors observed no survival differences between groups although a significant survival advantage was seen in diabetics treated with CABG and this benefit was also perceived in elderly patients. In both reports, number of involved vessels, presence of left anterior descending artery stenosis or poor left ventricular ejection fraction were no predictors of poor survival with PCI. Therefore, extent of the coronary artery disease (CAD) was not associated with poor outcome after PCI in the pre-drug eluting stent (DES) era. Recently, the ASCERT (Database Collaboration on the Comparative Effectiveness of Revascularization Strategies) registry found higher mortality rate with PCI in patients ≥ 65 years old in comparison with CABG, and advantages of surgery were seen in all subgroups including those at low risk. In this registry, PCI was accomplished by implantation of the first type of DES designs in 78% of cases. The intriguing observation of high mortality rate with PCI, including for non-diabetics and patients with two-vessel CAD, meaning a lack of clinical benefit with DES implantation, had not been seen previously. The study was not randomized, although its results are largely strengthened by its sample size. In this manuscript, the authors describe other registries and randomized trials reporting similar results supporting the findings of the aforementioned study and explore the reasons for these results, while also searching for potential solutions.