Evaluation of a high-dose dexamethasone-eluting stent

Pharmacological prevention of intimal hyperplasia: A state-of-the-art review

Intimal hyperplasia (IH) occurs in a considerable number of cases of blood vessel reconstruction by stenting or balloon angioplasty, venous bypass grafting, and arteriovenous dialysis accesses. It is triggered by endothelial injury during the vascular intervention and leads to vessel restenosis with life-threatening consequences for patients. To date, the drugs used for IH prevention in clinics-paclitaxel and rapalog drugs-have been focusing primarily on the vascular smooth muscle cell (VSMC) proliferation pathway of IH development. Limitations, such as endothelial toxicity and inappropriate drug administration timing, have spurred the search for new and efficient pharmacological approaches to control IH. In this state-of-the-art review, we present the pathways of IH development, focusing on the key events and actors involved in IH. Subsequently, we discuss different drugs and drug combinations interfering with these pathways based on their effect on peripheral circulation IH models in animal studies, or on clinical reports. The reports were obtained through an extensive search of peer-reviewed publications in Pubmed, Embase, and Google Scholar, with search equations composed based on five concepts around IH and their various combinations. To improve vascular intervention outcomes, rethinking of conventional therapeutic approaches to IH prevention is needed. Exploring local application of drugs and drug combinations acting on different pathophysiological pathways of IH development has the potential to provide effective and safe restenosis prevention.

Core-shell PVA/gelatin electrospun nanofibers promote human umbilical vein endothelial cell and smooth muscle cell proliferation and migration

Cardiovascular disease is the leading cause of death in the world. In this study, coaxial electrospinning is employed to fabricate fibers in a core-shell structure with polyvinyl alcohol (PVA) in the core and gelatin in the shell for evaluation as a potential vascular tissue engineering construct. PVA, a synthetic polymer, provides mechanical strength to the biocompatible and weak gelatin sheath. The HUVEC (human umbilical vein endothelial cells) and rSMC (rat smooth muscle cells) demonstrated a flattened morphology with multiple attachment sites on the gelatin and coaxial scaffolds, with an increase in cell spreading seen as mechanical stiffness of the scaffold increased. Additionally, HUVEC had an increase in migration on the coaxial scaffolds, which was attributed to the increase in stiffness; however, this increase in migration was not seen with the rSMC, which had the highest outward migration on the flat surfaces (tissue culture polystyrene and gelatin film). Overall, these scaffolds are appealing substrates for vascular tissue engineering applications.

STATEMENT OF SIGNIFICANCE

The worldwide burden of cardiovascular disease presents an ongoing need and opportunity for creating a variety of vascular prostheses. Fabrication of novel scaffolds and constructs for these are needed, providing strength and biological properties facilitating endothelial (EC) and smooth muscle (SMC) cell attachment, migration, and integration. Using electrospinning we formed 3D core:shell nanofibers and examined their effectiveness as substrates for EC and SMC attachment and growth, compared to a 2D (flat) substrate. We found that ECs attached and grew best on 3D core:shell fibers, whereas SMCs favored 2D gelatin surfaces. Interestingly, we found that EC attachment, migration and growth correlated and improved with increasing fiber stiffness. These materials and insights may foster novel vascular prostheses development.

Hemocompatibility of Poly(vinyl alcohol)-Gelatin Core-Shell Electrospun Nanofibers: A Scaffold for Modulating Platelet Deposition and Activation

In this study, we evaluate coaxial electrospun nanofibers with gelatin in the shell and poly(vinyl alcohol) (PVA) in the core as a potential vascular material by determining fiber surface roughness, as well as human platelet deposition and activation under varying conditions. PVA scaffolds had the highest surface roughness (Ra=65.5±6.8 nm) but the lowest platelet deposition (34.2±5.8 platelets) in comparison to gelatin nanofibers (Ra=36.8±3.0 nm and 168.9±29.8 platelets) and coaxial nanofibers (1 Gel:1 PVA coaxial, Ra=24.0±1.5 nm and 150.2±17.4 platelets. 3 Gel:1 PVA coaxial, Ra=37.1±2.8 nm and 167.8±15.4 platelets). Therefore, the chemical structure of the gelatin nanofibers dominated surface roughness in platelet deposition. Due to their increased stiffness, the coaxial nanofibers had the highest platelet activation rate, rate of thrombin formation, in comparison to gelatin and PVA fibers. Our studies indicate that mechanical stiffness is a dominating factor for platelet deposition and activation, followed by biochemical signals, and lastly surface roughness. Overall, these coaxial nanofibers are an appealing material for vascular applications by supporting cellular growth while minimizing platelet deposition and activation.

Stability and removal of dexamethasone sodium phosphate from wastewater using modified clays

Stability and removal of dexamethasone sodium phosphate (DSP) from wastewater produced at Al-Quds University Campus were investigated. Kinetic studies in both pure water and wastewater coming from secondary treatment (activated sludge) demonstrated that the anti-inflammatory DSP underwent degradation to its hydrolytic derivative, dexamethasone, in both media. The first-order hydrolysis rate of DSP in activated sludge at 25 degrees C (3.80 x 10(-6) s-1) was about 12-fold larger than in pure water (3.25 x 10(-7) s-1). The overall performance of the wastewater treatment plant (WWTP) installed in the University Campus was also assessed showing that 90% of spiked DSP was removed together with its newly identified metabolites by the ultra-filtration (UF) system, which consists of a UF hollow fibre (HF) with a 100-kDa cutoff membrane as the pre-polishing stage for the UF spiral wound with a 20-kDa cutoffmembrane. In testing other technologies, the effectiveness of adsorption and filtration by micelle-clay (MC) preparation for removing DSP was ascertained in comparison with activated charcoal. Batch adsorption in aqueous suspensions of the MC composite and activated carbon was well described by Langmuir isotherms showing the best results for MC material. Filtration of DSP water solutions demonstrated a significant advantage of columns filled in with a mixture of sand and MC complex in comparison with activated carbon/sand filters.

Stent hypersensitivity and infection in sinus cavities

Persistent mucosal inflammation, granulation tissue formation, hypersensitivity, and multifactorial infection are newly described complications of retained drug-eluting stents from endoscopic sinus surgery for refractory rhinosinusitis. In an important report published in Allergy and Rhinology, a 45-year-old male patient suffering from recalcitrant chronic rhinosinusitis underwent functional endoscopic sinus surgery and was found, for the first time, to have steroid-eluting catheters that were inadvertently left in the ethmoid and frontal sinuses. The retained catheters had caused persistent mucosal inflammation and formation of granulation tissue denoting hypersensitivity reaction. These consequences had induced perpetuation of symptoms of chronic rhinosinusitis. Meticulous removal of the retained stents with the nitinol wings from inflamed tissues of the frontal, ethmoidal, and sphenoethmoidal recesses in which they were completely imbedded was successfully performed without polypoid regrowth. Cultures of specimens taken from both left and right stents showed heavy growth of Stenotrophomonas maltophilia and moderate growth of Klebsiella oxytoca, coagulase negative Staphylococcus, and beta-hemolytic Streptococcus anginosus. Fungal infection was not detected. The current knowledge and experience regarding stent hypersensitivity and infection in relation with the use of stents in sinus cavities is reviewed.

Modulation of 11β-hydroxysteroid dehydrogenase as a strategy to reduce vascular inflammation

Atherosclerosis is a chronic inflammatory disease in which initial vascular damage leads to extensive macrophage and lymphocyte infiltration. Although acutely glucocorticoids suppress inflammation, chronic glucocorticoid excess worsens atherosclerosis, possibly by exacerbating systemic cardiovascular risk factors. However, glucocorticoid action within the lesion may reduce neointimal proliferation and inflammation. Glucocorticoid levels within cells do not necessarily reflect circulating levels due to pre-receptor metabolism by 11β-hydroxysteroid dehydrogenases (11β-HSDs). 11β-HSD2 converts active glucocorticoids into inert 11-keto forms. 11β-HSD1 catalyses the reverse reaction, regenerating active glucocorticoids. 11β-HSD2-deficiency/inhibition causes hypertension, whereas deficiency/inhibition of 11β-HSD1 generates a cardioprotective lipid profile and improves glycemic control. Importantly, 11β-HSD1-deficiency/inhibition is atheroprotective, whereas 11β-HSD2-deficiency accelerates atherosclerosis. These effects are largely independent of systemic risk factors, reflecting modulation of glucocorticoid action and inflammation within the vasculature. Here, we consider whether evidence linking the 11β-HSDs to vascular inflammation suggests these isozymes are potential therapeutic targets in vascular injury and atherosclerosis.

Dexamethasone-loaded block copolymer nanoparticles induce leukemia cell death and enhance therapeutic efficacy: a novel application in pediatric nanomedicine

Nanotechnology approaches have tremendous potential for enhancing treatment efficacy with lower doses of chemotherapeutics. Nanoparticle (NP)-based drug delivery approaches are poorly developed for childhood leukemia. Dexamethasone (Dex) is one of the most common chemotherapeutic drugs used in the treatment of childhood leukemia. In this study, we encapsulated Dex in polymeric NPs and validated their antileukemic potential in vitro and in vivo. NPs with an average diameter of 110 nm were assembled from an amphiphilic block copolymer of poly(ethylene glycol) (PEG) and poly(ε-caprolactone) (PCL) bearing pendant cyclic ketals (ECT2). The blank NPs were nontoxic to cultured cells in vitro and to mice in vivo. Encapsulation of Dex into the NPs (Dex-NP) did not compromise the bioactivity of the drug. Dex-NPs induced glucocorticoid phosphorylation and showed cytotoxicity similar to the free Dex in leukemic cells. Studies using NPs labeled with fluorescent dyes revealed leukemic cell surface binding and internalization. In vivo biodistribution studies showed NP accumulation in the liver and spleen with subsequent clearance of the particles with time. In a preclinical model of leukemia, Dex-NPs significantly improved the quality of life and survival of mice as compared to the free drug. To our knowledge, this is the first report showing the efficacy of polymeric NPs to deliver Dex to potentially treat childhood leukemia and reveals that low doses of Dex should be sufficient for inducing cell death and improving survival.

The evolving role of inflammatory biomarkers in risk assessment after stent implantation

The main adverse reactions to coronary stents are in-stent restenosis (ISR) and stent thrombosis. Along with procedural factors, individual susceptibility to these events plays an important role. In particular, inflammatory status, as assessed by C-reactive protein levels, predicts the risk of ISR after bare-metal stent implantation, although it does not predict the risk of stent thrombosis. Conversely, C-reactive protein levels fail to predict the risk of ISR after drug-eluting stent (DES) implantation, although they appear to predict the risk of stent thrombosis. Of note, DES have abated ISR rates occurring in the classical 1-year window, but new concern is emerging regarding late restenosis and thrombosis. The pathogenesis of these late events seems to be related to delayed healing and allergic reactions to polymers, a process in which eosinophils seem to play an important role by enhancing restenosis and thrombosis. The identification of high-risk individuals based on biomarker assessment may be important for the management of patients receiving stent implantation. In this report, we review the evolving role of inflammatory biomarkers in predicting the risk of ISR and stent thrombosis.

The inhibitory effect of dexamethasone on platelet-derived growth factor-induced vascular smooth muscle cell migration through up-regulating PGC-1α expression

Dexamethasone has been shown to inhibit vascular smooth muscle cell (VSMC) migration, which is required for preventing restenosis. However, the mechanism underlying effect of dexamethasone remains unknown. We have previously demonstrated that peroxisome proliferator-activated receptor gamma (PPARγ) coactivator-1 alpha (PGC-1α) can inhibit VSMC migration and proliferation. Here, we investigated the role of PGC-1α in dexamethasone-reduced VSMC migration and explored the possible mechanism. We first examined PGC-1α expression in cultured rat aortic VSMCs. The results revealed that incubation of VSMCs with dexamethasone could significantly elevate PGC-1α mRNA expression. In contrast, platelet-derived growth factor (PDGF) decreased PGC-1α expression while stimulating VSMC migration. Mechanistic study showed that suppression of PGC-1α by small interfering RNA strongly abrogated the inhibitory effect of dexamethasone on VSMC migration, whereas overexpression of PGC-1α had the opposite effect. Furthermore, an analysis of MAPK signal pathways showed that dexamethasone inhibited ERK and p38 MAPK phosphorylation in VSMCs. Overexpression of PGC-1α decreased both basal and PDGF-induced p38 MAPK phosphorylation, but it had no effect on ERK phosphorylation. Finally, inhibition of PPARγ activation by a PPARγ antagonist GW9662 abolished the suppressive effects of PGC-1α on p38 MAPK phosphorylation and VSMC migration. These effects of PGC-1α were enhanced by a PPARγ agonist troglitazone. Collectively, our data indicated for the first time that one of the anti-migrated mechanisms of dexamethasone is due to the induction of PGC-1α expression. PGC-1α suppresses PDGF-induced VSMC migration through PPARγ coactivation and, consequently, p38 MAPK inhibition.

Predictive value of C-reactive protein after drug-eluting stent implantation

During the last few decades, with the evolution of techniques and materials and the increasing experience of operators, percutaneous coronary interventions (PCI) have become an equally efficient alternative to coronary artery bypass grafts for the treatment of most coronary stenoses. Bare-metal stent implantation represented a major step forward, compared with plain old balloon angioplasty (POBA), by improving the immediate angiographic success. However, the incidence of in-stent restenosis (ISR) remained unacceptably high. Development of the drug-eluting stent (DES) significantly improved the outcome of PCI by dramatically abating the rate of ISR and reducing the incidence of target lesion revascularization. However, ISR has not been eliminated and the persistence of metal vessel scaffolding also raises concern regarding the occurrence of late or very late stent thrombosis. POBA and stent implantation have been shown to induce a local and systemic inflammatory response, whose magnitude is associated with worse clinical outcome, and they increase the risk of ISR. C-reactive protein, a marker of systemic inflammation, has been demonstrated to predict clinical and angiographic outcome after POBA or bare-metal stent implantation. However, conflicting data regarding the prognostic value of C-reactive protein following DES implantation are available. In this paper, we review the literature regarding the clinical and pathophysiological association between inflammation and prognosis after DES implantation and suggest some possible therapeutic approaches to reduce inflammatory burden with the aim to improve clinical and angiographic outcome after PCI.

Preventing restenosis in early drug-eluting stent era: recent developments and future perspectives

Restenosis is the major limitation of the successful therapy of percutaneous coronary intervention (PCI) for patients with coronary artery disease. The problem was appreciated in the late 1970s to early 1980s. Only in recent years, anti-restenotic therapy has achieved a breakthrough with the development of drug-eluting stents. Here, we provide an overview about pathological mechanisms of restenosis after PCI. Present therapeutic approaches to overcome restenosis and recent clinical results are revisited, and some major concerns in the post-drug-eluting stent era are discussed.

Therapeutic manipulation of glucocorticoid metabolism in cardiovascular disease

The therapeutic potential for manipulation of glucocorticoid metabolism in cardiovascular disease was revolutionized by the recognition that access of glucocorticoids to their receptors is regulated in a tissue-specific manner by the isozymes of 11beta-hydroxysteroid dehydrogenase. Selective inhibitors of 11beta-hydroxysteroid dehydrogenase type 1 have been shown recently to ameliorate cardiovascular risk factors and inhibit the development of atherosclerosis. This article addresses the possibility that inhibition of 11beta-hydroxsteroid dehydrogenase type 1 activity in cells of the cardiovascular system contributes to this beneficial action. The link between glucocorticoids and cardiovascular disease is complex as glucocorticoid excess is linked with increased cardiovascular events but glucocorticoid administration can reduce atherogenesis and restenosis in animal models. There is considerable evidence that glucocorticoids can interact directly with cells of the cardiovascular system to alter their function and structure and the inflammatory response to injury. These actions may be regulated by glucocorticoid and/or mineralocorticoid receptors but are also dependent on the 11beta-hydroxysteroid dehydrogenases which may be expressed in cardiac, vascular (endothelial, smooth muscle) and inflammatory (macrophages, neutrophils) cells. The activity of 11beta-hydroxysteroid dehydrogenases in these cells is dependent upon differentiation state, the action of pro-inflammaotory cytokines and the influence of endogenous inhibitors (oxysterols, bile acids). Further investigations are required to clarify the link between glucocorticoid excess and cardiovascular events and to determine the mechanism through which glucocorticoid treatment inhibits atherosclerosis/restenosis. This will provide greater insights into the potential benefit of selective 11beta-hydroxysteroid dehydrogenase inhibitors in treatment of cardiovascular disease.

Avoiding restenosis: is there a role for glucocorticoids in the drug-eluting stent era?

Restenosis is an important limitation of percutaneous coronary interventions (PCI). In-stent restenosis is mainly due to neointimal hyperplasia, a proliferative process modulated by inflammatory mechanisms. Numerous technical and pharmacological means have been tested to reduce restenosis rates, with frequently disappointing clinical results. Drug-eluting stents (DES) have demonstrated a high efficacy in reducing restenosis, but there are some associated problems that limit its generalized utilization. Glucocorticoids (GC), as potent anti-inflammatory agents, may exert beneficial effects on neointimal proliferation. Clinical studies with oral and intracoronary GC therapy have demonstrated reduction in restenosis rates in selected patients. Although further investigations are warranted, GC might have a potential role for restenosis prevention in selected cases.

Critical role of macrophages in glucocorticoid driven vascular calcification in a mouse-model of atherosclerosis

OBJECTIVE

Macrophage-derived products are known to play a crucial role during atherogenesis and vascular calcification. Glucocorticoids (GC) are important modulators of immune cell functions, but their specific effects on macrophages behavior during plaque formation are not defined. The present study was therefore designed to investigate the effects of macrophage-specific deletion of the glucocorticoid receptor (GR(LysMCre)) on atherogenesis and vascular calcification in a hyperlipidemic mouse-model.

METHODS AND RESULTS

Bone marrow was isolated from GR(LysMCre) mice and wild-type controls (GR(flox)) and subsequently transplanted into lethally irradiated LDL-receptor-deficient mice. Animals were fed a Western-type diet for 15 or 24 weeks, and atherosclerotic lesions within the aortic sinus were evaluated. At both time points, no significant difference in serum lipid and corticosterone concentrations, atherosclerotic lesion size and macrophage-content within the lesions could be observed. However, GR(LysMCre) mice showed less calcification as well as a significant reduction of RANKL, BMP2, and Msx2 expression within the vasculature. In vitro studies using conditioned media from macrophages which had been stimulated with dexamethasone demonstrated a dose-dependent increase in calcium deposition by vascular smooth muscle cells.

CONCLUSIONS

This study demonstrates that macrophage-specific glucocorticoid receptor inactivation reduces vascular calcification without affecting atherosclerotic lesion size in LDL receptor-deficient mice.

Glucocorticoids in the prevention of restenosis after coronary angioplasty: therapeutic potential

Vessel luminal narrowing after percutaneous coronary intervention (PCI) is characterised by platelet aggregation, release of growth factors, inflammatory cell infiltration, medial smooth muscle cell (SMC) proliferation, proteoglycan deposition and extracellular matrix remodelling. It is broadly accepted that the central mechanism at the basis of the whole pathophysiological process of restenosis is inflammation, triggered by vascular injury and activated through autocrine or paracrine mediators. Glucocorticosteroids exert beneficial effects on platelet function, on SMC proliferation and on collagen synthesis as well as inflammatory cell migration and activation, thus interfering with several steps of the cascade leading to neointima formation and subsequent late lumen loss. Initial experiences with systemic administration of glucocorticoids after PCI failed to confirm the expected benefits of this treatment, probably as a result of inadequate dosage and pharmacokinetic calculations. Recently a short-term, high-dose immunosuppressive treatment scheme with oral prednisone has demonstrated remarkable clinical and angiographic results when prednisone was given orally at a dose of 1 mg/kg for 10 days, 0.5 mg/kg for 20 days and 0.25 mg/kg for 15 days. This treatment has dramatically reduced the incidence of clinical vascular events at 1 year compared with controls (relative risk 0.34; 95% CI 0.12, 0.96; p = 0.006) and reduced the incidence of angiographic restenosis below 10% in different clinical and angiographic subsets. Secondary effects of a short course of glucocorticoids are generally minor, predictable and reversible: gastric pain, water and salt retention and worsened hypertension manifest in nearly 10% of patients. The addition of diuretics and acid suppressants before discharge, and the upgrading of antihypertensive medication thereafter, if needed, are useful preventive measures to control these temporary disorders. A routine blood cell count 4 weeks after PCI is advised in patients receiving thienopyridines (clopidogrel or ticlopidine) in addition to prednisone to rule out infrequent haematological dyscrasias. Emerging evidence supports this strategy as a convenient and well tolerated alternative to more expensive and complex revascularisation procedures such as drug eluting stent (DES) implantation or cardiac surgery, provided that the treatment is reserved for carefully selected candidates, i.e. after the exclusion of those with diabetes mellitus, a recent transmural myocardial infarction, or contraindications to the administration of a short-course of high-dose glucocorticosteroids. The recent concerns regarding the long-term safety of first-generation DES and the as yet undetermined duration of dual anti-platelet treatment, further supports the need for a simple pharmacological treatment that can be applied in a large percentage of patients currently treated with PCI. Multicentre randomised studies aimed at defining the efficacy and safety of oral prednisone treatment compared with metallic stents and DES are ongoing, and will become available in upcoming years.

Randomized comparison of dexamethasone-eluting stents with bare metal stent implantation in patients with acute coronary syndrome: serial angiographic and sonographic analysis

AIMS

The aim of this study is to compare the anti-inflammatory effect of the dexamethasone preloaded stent (Dexamet, Abbott, Galway, Ireland) with the bare metal stent (BMS; BiodivYsio, Biocompatibles Cardiovascular LTD, Galway, Ireland) in patients with acute coronary syndrome (ACS) assessed by angiographic (QCA) and intracoronary ultrasound (ICUS).

METHODS AND RESULTS

One hundred twenty patients with ACS were randomly assigned to revascularization using the Dexamet stent (n = 60) or BMS (n = 60). Serial QCA analysis and ICUS analysis were performed during long-term follow-up (2.9 F; 20 MHz transducer; Volcano Corp, Brussels, Belgium). Power calculations were performed for QCA-derived differences of lumen loss. In addition, statistical analysis was performed (SPSS for Windows 12.0.1). The target lesion revascularization rate was lower in the Dexamet group (10 [16.67%] vs 20 [33.33%] patients; P = .031). The QCA revealed improved lumen restoration in the Dexamet stent group (lumen loss, 0.55 +/- 0.65 vs 1.07 +/- 0.92 mm [P = .001]; loss index, 0.20 +/- 0.23 vs 0.46 +/- 0.42 [P < .001]). The ICUS revealed greater neointimal proliferation in the BMS versus the Dexamet stent group (3.36 +/- 1.03 vs 3.05 +/- 1.38 mm2; P < .001). Death (n = 1) and the number of total occlusions of the stent segment (n = 1) were identical in both groups.

CONCLUSION

Dexamet stents, in comparison with the BMS stents, reduced the target lesion revascularization rate in patients with ACS and lead to better lumen restoration during long-term follow-up.

Essential polyunsaturated fatty acids, inflammation, atherosclerosis and cardiovascular diseases

Atherosclerosis is the primary cause of coronary and cardiovascular diseases (CVD). Epidemiological studies have revealed several important environmental (especially nutritional) factors associated with atherosclerosis. However, progress in defining the cellular and molecular interactions involved has been hindered by the etiological complexity of the disease. Nevertheless, our understanding of CVD has improved significantly over the past decade owing to the availability of new randomized trial data. In particular, the failure of antioxidant and anti-inflammatory treatments to consistently reduce the rate of CVD complications suggests that theories of atherosclerosis may have considerably exaggerated the importance of oxidized lipoprotein and vascular inflammation. In that context, one new and basic question is whether the biology of essential dietary lipids may help us understand the role of the inflammatory process in CVD. Essential dietary lipids of the omega-6 and omega-3 families are the precursors of major mediators of inflammation such as eicosanoids that regulate the production of inflammatory cytokines and the expression of some major inflammation genes. On the other hand, non-essential lipids (omega-9 and saturated fatty acids) interfere with biological activities of essential lipids. Finally, essential omega-3 and omega-6 fatty acids have different, often antagonistic, effects on inflammation, and their effects can vary according to the type of cells and target organs involved, as well as their respective amounts in the diet. Because of the extreme complexity in the etiology of CVD, the best strategy may be to monitor the main features of dietary patterns, such as the Mediterranean diet, that are known to be associated with a low prevalence of both CVD and chronic inflammatory diseases.

The favorable clinical and angiographic outcomes of a high-dose dexamethasone-eluting stent: randomized controlled prospective study

BACKGROUND

Previous studies with dexamethasone-eluting stents could not elucidate the role of dexamethasone in the prevention of neointimal hyperplasia because they did not compare their results with a control group. We prospectively evaluated the clinical and angiographic outcomes of dexamethasone-eluting stents, comparing them with unloaded stents of an identical design.

METHODS

A total of 92 patients (98 lesions) were randomly assigned to the dexamethasone group (67 patients, 71 lesions) or control group (25 patients, 27 lesions). The inclusion criteria for a stent implantation were a de novo lesion with a diameter of 2.60 to 4.0 mm. BiodivYsio Drug Delivery phosphorylcholine-coated stents (Biocompatibles Ltd, Galway, Ireland) were immersed in a 20-mg/mL dexamethasone solution, yielding a total dexamethasone dose of 0.5 microg/mm2 per stent.

RESULTS

The total major adverse cardiac events rate at 12 months was significantly lower in the dexamethasone group, as compared with the control group (10.4% [7/67] vs 28.0% [7/25], P = .037). The binary restenosis rate at 6 months was 11.9% (7/59) in the dexamethasone group and 42.9% (9/21) in the control group (P = .002). The use of dexamethasone-eluting stents was the only independent predictor for the major adverse cardiac event at 12 months (relative risk 0.20, 95% CI 0.06-0.68, P = .009) and binary restenosis at 6 months (relative risk 0.17, 95% CI 0.05-0.60, P = .006) by multivariate analysis.

CONCLUSIONS

Dexamethasone-eluting stents exhibited an improvement in the clinical and angiographic outcomes, as compared with the control stents. These results suggest that dexamethasone may play an important role in the inhibition of the polymer-induced inflammation in the era of drug-eluting stents.

Steroid-eluting stents in patients with acute coronary syndrome: the dexamethasone eluting stent Italian registry

OBJECTIVE

To assess immediate and mid-term clinical and angiographic outcomes of the dexamethasone drug-eluting stent (D-DES) in patients with acute coronary syndrome (ACS).

PATIENTS AND METHODS

A prospective, nationwide, controlled, registry. Inflammation plays a key role in ACS, and the anti-inflammatory effects of local elution of dexamethasone in unstable plaques may represent a valid therapeutic approach. All patients had ACS on admission (n = 332). 81.5% of the patients had unstable angina and 18.5% had non-ST elevation myocardial infarction (MI). 47% had ST-T segment changes, 59% had troponin elevation, 77% had elevated C-reactive protein levels and 48% had intermediate-high Thrombolysis in Myocardial Infarction risk score. Patients were treated according to an early invasive approach with 420 D-DES in 387 coronary lesions. Primary end point was the cumulative incidence of death, MI and ischaemia-driven target vessel revascularisation (TVR) at 6 months.

RESULTS

At 30 days, 2 (0.6%) patients died, and sub-acute stent thrombosis occurred in 2 patients. At 6 months, 328 (98.8%) patients were controlled, 3 (0.9%) patients had died, 7 (2.1%) had MI and 28 (8.5%) underwent ischaemia-driven TVR. Therefore, the primary end point occurred in 11.5% of patients. At multivariate analysis, multi-vessel coronary artery disease (odds ratio (OR) = 2.16, 95% CI = 1.47 to 3.17, p = 0.0001) and vessel diameter < or =2.75 mm (OR = 1.64, 95% CI = 1.08 to 2.49, p = 0.02) were independent predictors of 6-month clinical events. Global angiographic restenosis rate was 33.3%.

CONCLUSION

This is the first large, multicentre analysis of the clinical and angiographic outcomes obtained with D-DES implanted in ACS. D-DES offers a low rate of clinical events at 6 months, but has no anti-restenosis effect.

Short-term dexamethasone treatment inhibits vein graft thickening in hypercholesterolemic ApoE3Leiden transgenic mice

OBJECTIVE

The aim of this study was to assess whether the anti-inflammatory agent dexamethasone can inhibit vein graft thickening without the occurrence of serious side effects.

METHODS

Venous interposition grafting was performed in the common carotid artery of hypercholesterolemic ApoE3Leiden transgenic mice. Mice were treated with dexamethasone (0.15 mg.kg(-1).d(-1) orally), and after 28 days, vein graft thickening was quantified.

RESULTS

Treatment with dexamethasone resulted in a significant 43% reduction in lesion area without changes in lesion composition when compared with nontreated controls. However, dexamethasone, when administered for a prolonged period of time, is known for its potentially serious side effects. To overcome these potential side effects of prolonged dexamethasone treatment, the effect of a short-term 7-day dexamethasone treatment was studied. This short dexamethasone treatment resulted in a 49% decrease of vein graft thickening at 28 days. Furthermore, it was demonstrated that dexamethasone treatment led to reduced local expression of several proinflammatory cytokines and factors in the vein grafts 24 hours after surgery. Finally, observations in mice were verified in human saphenous organ cultures. Exposure to dexamethasone for either 7 or 28 days significantly reduced intimal hyperplasia formation on cultured saphenous vein segments.

CONCLUSIONS

Short-term anti-inflammatory treatment with dexamethasone leads to a significant reduction in vein graft thickening over an extended period, possibly by the reduction of early expression of proinflammatory cytokines. This 7-day treatment minimizes the risk of unwanted side effects of long-term dexamethasone treatment and may be a new approach to prevent graft failure.

Drug-eluting stents studies in mice: Do we need atherosclerosis to study restenosis?

In 2001, the first human study with drug-eluting stents (DES) was published showing a nearly complete abolition of restenosis by using a sirolimus-eluting stent. This success was very encouraging to test new compounds in combination with the DES platform. Nevertheless, several other anti-restenotic compounds have been used in human clinical trials with disappointing outcomes. Little is known concerning potential adverse effects on vessel wall integrity and (re)healing, atherosclerotic lesion formation, progression, and plaque stability of these DES. Although efficacy and safety need to be determined clinically, preclinical testing of candidate drugs in well-defined animal models is extremely helpful to gain insight into the basic biological responses to candidate compounds. Here, we discuss and report an animal model which enables rapid screening of candidate drugs for DES on an atherosclerotic background. The results from drug testing using this novel model could help to quickly and cost-effectively establish the dose range of candidate drugs with reasonable potential for DES.

C-Reactive protein, clinical outcome, and restenosis rates after implantation of different drug-eluting stents

Sirolimus-eluting stents (SESs), paclitaxel-eluting stents (PESs), and dexamethasone-eluting stents (DEXs) have anti-inflammatory properties; thus, the decreased in-segment restenosis rate observed with the use of these stents might be related to a weaker postprocedural inflammatory response. One hundred sixty consecutive patients with stable coronary artery disease who underwent successful single-vessel/lesion coronary artery stenting were prospectively studied. Thin-strut bare metal stents were deployed in 39 patients, SESs in 30, PESs in 61, and DEXs in 30. The 4 groups were similar with respect to demographic and angiographic variables and prevalence of risk factors. C-reactive protein (CRP) was measured at baseline and 24 and 48 hours after the procedure. Maximal increase in CRP was calculated as the increase in CRP at 48 hours/CRP compared with baseline. Angiographic follow-up was performed after 12.9 +/- 1.3 months or sooner, if needed, on the basis of clinical evidence. All patients presented a postprocedural increase in CRP that peaked at 48 hours (median 10.0 mg/L). Maximal CRP increase was similar across the 4 groups (medians 3.5 mg/L in the bare metal stent group, 3.6 mg/L in the SES group, 4.0 mg/L in the PES group, 3.5 mg/L in the DEX group, p = 0.45). Incidences of angiographic binary restenosis (>50% lumen diameter decrease) were 20.5% in the bare metal stent group, 3.3% in the SES group, 4.9% in the PES group, and 36.6% in the DEX group (p = 0.0004 for SES and PES groups vs bare metal stent and DEX groups). Postprocedural increase in CRP was significantly correlated with clinical and angiographic outcomes. In conclusion, the acute postprocedural systemic inflammatory response induced by drug-eluting stent implantation appears to be similar to that induced by bare metal stents. However, the restenosis rate is lower for SESs and PESs than for DEXs and bare metal stents. Thus, the decreased incidence of stent restenosis that was observed after SES and PES deployment is unlikely to be related to a decreased acute systemic inflammatory response, but rather to an increased local resistance to inflammatory mediators.

Guidelines for percutaneous coronary interventions. The Task Force for Percutaneous Coronary Interventions of the European Society of Cardiology

In patients with stable CAD, PCI can be considered a valuable initial mode of revascularization in all patients with objective large ischaemia in the presence of almost every lesion subset, with only one exception: chronic total occlusions that cannot be crossed. In early studies, there was a small survival advantage with CABG surgery compared with PCI without stenting. The addition of stents and newer adjunctive medications improved the outcome for PCI. The decision to recommend PCI or CABG surgery will be guided by technical improvements in cardiology or surgery, local expertise, and patients' preference. However, until proved otherwise, PCI should be used only with reservation in diabetics with multi-vessel disease and in patients with unprotected left main stenosis. The use of drug-eluting stents might change this situation. Patients presenting with NSTE-ACS (UA or NSTEMI) have to be stratified first for their risk of acute thrombotic complications. A clear benefit from early angiography (<48 h) and, when needed, PCI or CABG surgery has been reported only in the high-risk groups. Deferral of intervention does not improve outcome. Routine stenting is recommended on the basis of the predictability of the result and its immediate safety. In patients with STEMI, primary PCI should be the treatment of choice in patients presenting in a hospital with PCI facility and an experienced team. Patients with contra-indications to thrombolysis should be immediately transferred for primary PCI, because this might be their only chance for quickly opening the coronary artery. In cardiogenic shock, emergency PCI for complete revascularization may be life-saving and should be considered at an early stage. Compared with thrombolysis, randomized trials that transferred the patients for primary PCI to a 'heart attack centre' observed a better clinical outcome, despite transport times leading to a significantly longer delay between randomization and start of the treatment. The superiority of primary PCI over thrombolysis seems to be especially clinically relevant for the time interval between 3 and 12 h after onset of chest pain or other symptoms on the basis of its superior preservation of myocardium. Furthermore, with increasing time to presentation, major-adverse-cardiac-event rates increase after thrombolysis, but appear to remain relatively stable after primary PCI. Within the first 3 h after onset of chest pain or other symptoms, both reperfusion strategies seem equally effective in reducing infarct size and mortality. Therefore, thrombolysis is still a viable alternative to primary PCI, if it can be delivered within 3 h after onset of chest pain or other symptoms. Primary PCI compared with thrombolysis significantly reduced stroke. Overall, we prefer primary PCI over thrombolysis in the first 3 h of chest pain to prevent stroke, and in patients presenting 3-12 h after the onset of chest pain, to salvage myocardium and also to prevent stroke. At the moment, there is no evidence to recommend facilitated PCI. Rescue PCI is recommended, if thrombolysis failed within 45-60 min after starting the administration. After successful thrombolysis, the use of routine coronary angiography within 24 h and PCI, if applicable, is recommended even in asymptomatic patients without demonstrable ischaemia to improve patients' outcome. If a PCI centre is not available within 24 h, patients who have received successful thrombolysis with evidence of spontaneous or inducible ischaemia before discharge should be referred to coronary angiography and revascularized accordingly--independent of 'maximal' medical therapy.