Prospective randomized trial of corticosteroids for the prevention of restenosis after intracoronary stent implantation

The safety of pulse corticosteroid therapy- Systematic review and meta-analysis

OBJECTIVE

To amass all available evidence from randomized controlled trials regarding the safety of pulse corticosteroids therapy, in order to establish its safety.

PATIENTS AND METHODS

All electronic databases from 1/1966 up to 02/2019 were reviewed to find all randomized controlled trials comparing pulse corticosteroids to oral corticosteroids or to placebo/no treatment. Two reviewers independently extracted and recorded data regarding type of corticosteroid treatment, dosages, length of treatment and follow-up. Risk ratios (RR) with 95% (CI) for differences between pulse corticosteroids and comparator were pooled using a fixed effect meta-analysis. The primary outcome was occurrence of severe adverse events (SAEs). Secondary outcomes included any adverse events (AEs), AEs requiring discontinuation, AEs per system involved and all-cause mortality.

RESULTS

A total of 64 trials were included: 18 trials which compared pulse corticosteroids to oral corticosteroids and 46 trials which compared pulse corticosteroids to placebo/no intervention. Pulse corticosteroids was not associated with increased risk for SAEs for both comparators: RR 0.77 (95% CI 0.52-1.14), and RR 0.99 (95% CI 0.93-1.06), respectively. Sensitivity analysis based on adequate allocation concealment and use of a valid AE grading did not alter the results. Subgroup analysis revealed no increased risk of specific SAEs or AEs with pulse corticosteroids compared to oral corticosteroids.

CONCLUSION

Pulse corticosteroids was not associated with an increase risk of SAEs and should be regarded as safe.

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.

Immunosuppressive therapy with oral prednisone to prevent restenosis after PCI. A multicenter randomized trial

BACKGROUND

Prednisone at immunosuppressive doses after stenting has shown remarkable efficacy in reducing ischemic recurrences in nondiabetic patients with high post-procedural levels of C-reactive protein; the study aim was to compare the clinical outcome obtained in a control group of patients treated with bare metal stents versus 2 other study groups--bare metal stent plus oral prednisone or drug eluting stents--assuming similar optimal adjunctive medical treatment.

METHODS

Five tertiary Italian hospitals enrolled 375 nondiabetic patients with coronary artery disease and no contraindications to dual antiplatelet treatment or corticosteroid therapy in a randomized, controlled study performed between 2007 and 2009. Patients were allocated into 3 study groups: bare metal stents (controls), bare metal stents followed by a 40-day prednisone treatment, or drug-eluting stents. The primary endpoint was the event-free survival of cardiovascular death, myocardial infarction, and recurrence of ischemia needing repeated target vessel revascularization at 1 year as adjudicated by an independent clinical events committee.

RESULTS

One-year follow-up was obtained in all patients. Patients receiving bare metal stents alone as compared to those treated with prednisone or drug-eluting stents had lower event-free survival; the primary endpoint was 80.8% in controls compared to 88.0% in the prednisone and 88.8% in the drug-eluting stent groups, respectively (P=.04 and .006).

CONCLUSION

Compared with bare metal stents alone, prednisone treatment after bare metal stents or drug-eluting stent implantation result in a better event-free survival at 1 year.

Therapeutic potential for protein kinase C inhibitor in vascular restenosis

Vascular restenosis, an overreaction of biological response to injury, is initialized by thrombosis and inflammation. This response is characterized by increased smooth muscle cell migration and proliferation. Available pharmacological treatments include anticoagulants, antiplatelet agents, immunosuppressants, and antiproliferation agents. Protein kinase C (PKC), a large family of serine/threonine kinases, has been shown to participate in various pathological stages of restenosis. Consequently, PKC inhibitors are expected to exert a wide range of pharmacological activities therapeutically beneficial for restenosis. In this review, the roles of PKC isozymes in platelets, leukocytes, endothelial cells, and smooth muscle cells are discussed, with emphasis given to smooth muscle cells. We will describe cellular and animal studies assessing prevention of restenosis with PKC inhibitors, particularly targeting -α, -β, -δ, and -ζ isozymes. The delivery strategy, efficacy, and safety of such PKC regulators will also be 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.

Glucocorticoids and cardiovascular disease

Chronic excessive activation of glucocorticoid receptors induces obesity, insulin resistance, glucose intolerance, dyslipidaemia and hypertension. Subtle abnormalities of the hypothalamic-pituitary-adrenal axis and/or of tissue sensitivity to glucocorticoids are also associated with these cardiovascular risk factors in patients with the metabolic syndrome. Furthermore, glucocorticoids have direct effects on the heart and blood vessels, mediated by both glucocorticoid and mineralocorticoid receptors and modified by local metabolism of glucocorticoids by the 11beta-hydroxysteroid dehydrogenase enzymes. These effects influence vascular function, atherogenesis and vascular remodelling following intra-vascular injury or ischaemia. This article reviews the systemic and cardiovascular effects of glucocorticoids, and the evidence that glucocorticoids not only promote the incidence and progression of atherogenesis but also modify the recovery from occlusive vascular events and intravascular injury. The conclusion is that manipulation of glucocorticoid action within metabolic and cardiovascular tissues may provide novel therapeutic avenues to combat cardiovascular disease.

The cell cycle: a critical therapeutic target to prevent vascular proliferative disease

Percutaneous coronary intervention is the preferred revascularization approach for most patients with coronary artery disease. However, this strategy is limited by renarrowing of the vessel by neointimal hyperplasia within the stent lumen (in-stent restenosis). Vascular smooth muscle cell proliferation is a major component in this healing process. This process is mediated by multiple cytokines and growth factors, which share a common pathway in inducing cell proliferation: the cell cycle. The cell cycle is highly regulated by numerous mechanisms ensuring orderly and coordinated cell division. The present review discusses current concepts related to regulation of the cell cycle and new therapeutic options that target aspects of the cell cycle.

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.

Percutaneous treatment of coronary bifurcations: lesion preparation before provisional bare metal stenting and subsequent immunosuppression with oral prednisone. The IMPRESS-Y study

Aim of the study was to assess the clinical and angiographic efficacy of oral treatment with prednisone at immunosuppressive dosage after percutaneous coronary interventions (PCI) in patients with bifurcation lesions treated with elective bare metal stent (BMS) implantation in the main-branch (MB) and provisional stenting in the side-branch (SB). Twenty-five patients were treated on 29 bifurcation lesions (58 vessel segments). Lesion preparation before stenting was performed with atherectomy in 7 cases, and balloon PCI over double wires in all other cases; none was treated directly with stents. The mean length of stents implanted in the MB was 19.6 +/- 4.9 mm (10-30 mm). Balloon PCI was successful in 23 of 29 SB and provisional stenting was needed in 6 SB (21%). All patients received oral prednisone according to the immunosuppressive protocol previously reported (1 mg/kg/day/10 days, 0.5 mg/kg/day/20 days, 0.25 mg/kg/day/15 days). At 12 months, one patient had recurrence of angina (4%) and two patients underwent repeated target lesion revascularization (8%). No patient died or had stent thrombosis. Quantitative coronary analysis was performed in all patients at 8 months. Global restenosis rate per vessel was 8.6% (5/58), and 17.2% (5/29) per lesion. The restenosis rate and late lumen loss were 3.4% and 0.36 +/- 0.6 mm, and 13.8% and 0.47 +/- 0.46 mm in the MB and the SB, respectively. Single stent implantation in the MB and provisional stenting of the SB is feasible in most cases after adequate lesion preparation. The systemic treatment with oral prednisone after BMS implantation offers good clinical and angiographic results even in the difficult setting of bifurcation lesions.

Comparison of efficacy and safety of lower-dose to higher-dose oral prednisone after percutaneous coronary interventions (the IMPRESS-LD study)

This study assessed clinical and angiographic efficacies of oral treatment with prednisone at low-dose (LD) versus the previous high-dose (HD) immunosuppressive dosage used after percutaneous coronary interventions (PCIs) with bare metal stents in patients with multivessel coronary artery disease. Forty-three patients with multivessel disease successfully treated with multiple PCIs were matched to the previous HD IMPRESS-2/MVD study population. The 43 patients were treated for 103 coronary stenoses and received 30-day oral prednisone treatment (LD group 1 mg/kg for 5 days, 0.5 mg/kg for 10 days, 0.25 mg/kg for 15 days) and were compared retrospectively with the 43 patients in the HD IMPRESS-2/MVD study with 116 treated coronary lesions (HD group 1 mg/kg for 10 days, 0.5 mg/kg for 20 days, 0.25 mg/kg for 15 days). The primary clinical end point was 12-month event-free survival rate (defined as freedom from death, myocardial infarction, and need for target vessel revascularization). The secondary end point was angiographic restenosis at 8 months assessed by quantitative coronary angiography. Event-free survival rates were 74% and 93% in the LD and HD groups, respectively (relative risk 4.6, 95% confidence interval 1.18 to 17.8, p = 0.019). Restenosis was observed in 4 lesions (4%) in the HD group and in 20 lesions (22%) in the LD group (p <0.001). Mean late lumen loss was 0.61 +/- 0.35 mm, and the loss index was 31.3 +/- 21.6% in the HD group compared with 0.87 +/- 0.61 mm and 52.03 +/- 25.1% in the LD group (p = 0.03 and 0.02, respectively). In conclusion, antirestenotic efficacy of oral treatment with prednisone after conventional PCI is dose sensitive. A 50% dose decrease in oral prednisone, as tested in this study, is less effective than the previously tested HD IMPRESS therapeutic scheme.

Systemic immunosuppressive therapy inhibits in-stent restenosis in patients with renal allograft

BACKGROUND

Cyclosporine is used routinely for prophylaxis for renal allograft rejection. In experimental animal studies, cyclosporine had been shown to inhibit smooth muscle cell proliferation during the arterial response to injury. We investigated whether systemic immunosuppression may inhibit in-stent restenosis in renal transplant patients undergoing coronary stenting.

METHODS

From 1993 to 2003, 33 renal transplant patients with 45 coronary lesions and 37 dialysis patients with 52 lesions underwent coronary stenting using bare metal stents at our center. We followed all patients clinically for a mean period of 37 +/- 31 months and 40 patients angiographically at 14 +/- 15 months after coronary intervention. Cyclosporine was combined with corticosteroids in 32 patients and one patient received tacrolimus instead of cyclosporine.

RESULTS

The baseline clinical and angiographical characteristics were similar and the success rate of the procedure was 100% in both groups. In renal transplant group, the mean dose of cyclosporine was 192.5 +/- 68 mg/day and the blood cyclosporine level at the time of procedure was 152.9 +/- 51.5 ng/mL. The rate of in-stent restenosis was 7.1% in renal transplant group and 57.1% in dialysis group (P < 0.0001). The mean late loss was 0.47 +/- 0.57 mm in renal transplant group when compared with 1.51 +/- 1.09 mm in dialysis group (P = 0.004). The overall rate of major adverse cardiac events (MACEs) was 6.1% in renal transplant group and 35.1% in dialysis group (P < 0.0001).

CONCLUSIONS

Renal transplant patients receiving combined immunosuppressive agents showed markedly low rates of in-stent restenosis and MACE after coronary revascularization with stent. We consider that this result may be related to the ability of combined immunosuppressive therapy to inhibit inflammatory reaction and vascular smooth muscle cell proliferation induced by coronary stenting.

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.

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 Coronary Stents

The introduction and widespread use of coronary stents have been the most important advancement in the percutaneous treatment of coronary artery disease since the introduction of balloon angioplasty. Coronary artery stents reduce the rate of angiographic and clinical restenosis compared to balloon angioplasty. This angiographic restenosis was further reduced with the introduction of drug-eluting stents and hence further reduction in the frequency of major adverse cardiac events. Herein we present a comprehensive and up-to-date review about the use of drug-eluting stents in the treatment of coronary artery disease.

Dexamethasone could improve myocardial infarction outcomes and provide new therapeutic options for non-interventional patients

BACKGROUND

Statins reduce death and morbidity of acute myocardial infarction in part through immunosuppressive mechanisms, suggesting glucocorticoids could produce similar benefits. Glucocorticoids inhibit proliferation of smooth muscle cells and activation of macrophages within atherosclerotic plaques and protect ischemic myocardium through inhibition of a heat shock protein. Dexamethasone-eluting coronary stents have a decreased rate of restenosis, and oral prednisone reduces restenosis of conventional stents. Some studies from the 1970's and 1980's showed that steroids improve survival in myocardial infarction, but no conclusive large-scale randomized well-powered trials have been conducted.

PRESENTATION OF THE HYPOTHESIS

Dexamethasone administered alongside statins in the setting of acute myocardial infarction could attenuate myocardial damage in patients with diffuse disease.

TESTING THE HYPOTHESIS

Patients with acute myocardial infarction who cannot undergo angioplasty or coronary artery bypass grafting could be given a statin and intravenous and oral dexamethasone. Dexamethasone minimizes fluid retention and avoids mineralocorticoid-induced cell proliferation in plaques. Blood glucose monitoring should be ordered for all patients, but diabetic patients need not be excluded. There should be measures to prevent steroid-induced homocystinuria or more common complications such as ulcers, osteoporosis, infections and psychosis.

IMPLICATIONS OF THE HYPOTHESIS

Showing that acute coronary syndrome is a steroid-responsive disorder would have immediate relevance for patients limited to medical management because of anatomy and comorbidities, and results would similarly have application for acute ischemic stroke.

Coronary stenting and inflammation

Restenosis after stent implantation is mainly caused by neointimal proliferation through the stent struts. Experimental studies performed in the last decade indicate that inflammatory mechanisms play a key role in the process of neointimal proliferation and restenosis. Coronary stenting is a strong inflammatory stimulus, and the acute local and systemic inflammatory responses to local inflammation produced by coronary stenting are highly individual and predictive of restenosis and event-free survival. The benefit of anti-inflammatory periprocedural therapy, such as with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) and steroids, and long-term follow-up is dependent on the individual's inflammatory status. Measurement of acute-phase reactants, such as C-reactive protein plasma concentration, appears to be important for the identification of subjects at high risk and the development of specific treatment tailored to individual patients.

Pharmacological treatment for prevention of restenosis

Coronary artery disease (CAD) is the leading cause of mortality and morbidity among adults in the Western world. Coronary artery bypass grafting and percutaneous coronary interventions (PCI) have gained widespread acceptance for the treatment of symptomatic CAD. There has been an explosive growth worldwide in the utilisation of PCI, such as balloon angioplasty and stenting, which now accounts for over 50% of coronary revascularisation. Despite the popularity of PCI, the problem of recurrent narrowing of the dilated artery (restenosis) continues to vex investigators. In recent years, significant advances have occurred in the understanding of restenosis. Two processes seem to contribute to restenosis: remodelling (vessel size changes) and intimal hyperplasia (vascular smooth muscle cell [VSMC] proliferation and extracellular matrix [ECM] deposition). Despite considerable efforts, pharmacological approaches to decrease restenosis have been largely unsuccessful and the only currently applied modality to reduce the restenosis rate is stenting. However, stenting only prevents remodelling and does not inhibit intimal hyperplasia. Several potential targets for inhibiting restenosis are currently under investigation including platelet activation, the coagulation cascade, VSMC proliferation and migration, and ECM synthesis. In addition, new approaches for local drug therapy, such as drug eluting stents, are currently being evaluated in preclinical and clinical studies. In this article, we critically review the current status of drugs that are being evaluated for restenosis at various stages of development (in vitro, preclinical animal models and human trials).

Dexamethasone-eluting stent: an anti-inflammatory approach to inhibit coronary restenosis

The long-term efficacy of percutaneous coronary interventions is still hampered by restenosis. Restenosis is the result of a complex pathophysiological process, which is thought to be caused by an exaggerated healing response induced by the vascular injury caused by the percutaneous coronary interventions and the implantation of a foreign body (the stent). There is increasing evidence that inflammation plays an important role in the initiation and development of neointimal hyperplasia and subsequent restenosis. Dexamethasone (Decadron, Merck Sharpe and Dohme Ltd) is a glucocorticoid with well-known potent anti-inflammatory and antiproliferative properties. Early studies using either systemic or local delivery of dexamethasone have shown limited beneficial effects on restenosis. The dexamethasone-eluting stent (Dexamet, Abbott Vascular Devices Ltd) is one of the first generation of drug-eluting stents for local drug delivery to prevent restenosis. Preclinical studies demonstrated that implantation of dexamethasone-loaded coronary stents was safe and had a beneficial effect on stent implantation-related inflammation. A pilot trial suggested a beneficial effect on restenosis. Large randomized trials are underway to confirm these findings. This article reviews the potential role of inflammation in the pathogenesis of restenosis and the efficacy of dexamethasone in the prevention of restenosis.

Evaluation of a high-dose dexamethasone-eluting stent

This study evaluated the safety and efficacy of a dexamethasone-eluting stent with a special high dexamethasone-loading dose for treatment of de novo coronary lesions in 30 patients. Eight patients had in-stent restenosis (restenosis rate 31%) at 6-month follow-up, and the in-stent late lumen loss was 0.96 +/- 0.63 mm due to an average intimal hyperplasia area obstruction of 32 +/- 21%, indicating that high-dose dexamethasone-loaded stents do not significantly reduce neointimal proliferation.

Non–Polymer-Based Paclitaxel-Coated Coronary Stents for the Treatment of Patients With De Novo Coronary Lesions

BACKGROUND

Paclitaxel, a microtubule-stabilizing compound with potent antitumor activity, has been shown to inhibit smooth muscle cell proliferation and migration. The DELIVER trial was a prospective, randomized, blinded, multicenter clinical evaluation of the non-polymer-based paclitaxel-coated ACHIEVE stent compared with the stainless steel Multi-Link (ML) PENTA stent.

METHODS AND RESULTS

A total of 1043 patients with focal de novo coronary lesions, <25 mm in length, in 2.5- to 4.0-mm vessels were randomized (ACHIEVE n=524; ML PENTA n=519). Angiographic follow-up was performed in a subset of 442 patients (ACHIEVE n=228; ML PENTA n=214). Prespecified end points were a 40% reduction in target-vessel failure at 9 months (primary clinical end point) and a 50% reduction in binary restenosis at 8 months (major secondary end point). Baseline clinical characteristics were comparable between the groups. Patients in ACHIEVE had more type C lesions and a larger reference diameter. At follow-up, stent late loss was 0.81 versus 0.98 mm (P=0.003), stent binary restenosis was 14.9% versus 20.6% (P=0.076), and target-vessel failure was 11.9% versus 14.5% (P=0.12) for ACHIEVE and ML PENTA, respectively.

CONCLUSIONS

The ACHIEVE paclitaxel-coated stent decreased neointimal proliferation compared with the bare-metal PENTA stent; however, this reduction was insufficient to meet the prespecified primary end point of target-vessel failure and the secondary end point of binary restenosis.

Intracoronary brachytherapy for the prevention of restenosis after percutaneous coronary revascularization

PURPOSE

The purpose of this article is to review the current literature pertaining to intracoronary brachytherapy for the prevention of restenosis after percutaneous coronary revascularization (PCR).

METHODS

English-language articles were identified through a MEDLINE search (January 1984 to January 2003) using the keywords brachytherapy, radioactive stents, and coronary arteries. In addition, pertinent reference citations from relevant articles were reviewed.

RESULTS

Restenosis after PCR is a complex process, thought to be due to a combination of vessel wall remodeling and neointimal proliferation. To date, catheter-based delivery of intracoronary brachytherapy has been found to prevent vessel wall remodeling and causes a reduction in the proliferation of the neointima. Neointimal proliferation, as measured by mean neointimal area, was reduced in all animal studies (range 26%-91%). In contrast, animal studies examining radioactive stents demonstrated an increase in neointimal proliferation, suggesting that they may not be helpful at preventing post-PCR restenosis. All human studies using catheter-based intracoronary brachytherapy for in-stent restenosis have employed either beta (beta) or gamma (gamma) radiation sources with variable doses of radiation (range 7-56 Grays [Gy]). Restenosis occurred in 12% to 40% of patients in nonrandomized studies, and clinical events occurred in 13% to 50% of patients. To date, there have been 7 published randomized trials in humans comparing catheter-based intracoronary brachytherapy to placebo, with a total of 1047 patients. The dose of radiation in the trials ranged from 14 Gy to 30 Gy. During follow-up, 8% to 33% of patients who received brachytherapy had restenosis versus 39% to 64% of patients receiving placebo. Clinical events occurred in 19% to 50% among patients who received brachytherapy versus 29% to 79% among patients receiving placebo. The majority of human studies examining radioactive stents do not demonstrate a reduction in restenosis in patients post-PCR. There are no randomized trials examining radioactive stents in humans.

CONCLUSION

Nonrandomized studies of radioactive stents suggest they are not effective at preventing in-stent restenosis. In contrast, data from animal and human studies suggest that catheter-based intracoronary brachytherapy can prevent in-stent restenosis and reduce clinical events post-PCR.

Lipaemia, Inflammation and Atherosclerosis

Atherosclerosis is the major cause of death in the world. Fasting and postprandial hyperlipidaemia are important risk factors for coronary heart disease (CHD). Recent developments have undoubtedly indicated that inflammation is pathophysiologically closely linked to atherogenesis and its clinical consequences. Inflammatory markers such as C-reactive protein (CRP), leucocyte count and complement component 3 (C3) have been linked to CHD and to hyperlipidaemia and several other CHD risk factors. Increases in these markers may result from activation of endothelial cells (CRP, leucocytes, C3), disturbances in adipose tissue fatty acid metabolism (CRP, C3), or from direct effects of CHD risk factors (leucocytes). It has been shown that lipoproteins, triglycerides, fatty acids and glucose can activate endothelial cells, most probably as a result of the production of reactive oxygen species. Similar mechanisms may also lead to leucocyte activation. Increases in triglycerides, fatty acids and glucose are common disturbances in the metabolic syndrome and are most prominent in the postprandial phase. People are in a postprandial state most of the day, and this phase is proatherogenic. Inhibition of the activation of leucocytes, endothelial cells, or both, is an interesting target for intervention, as activation is obligatory for adherence of leucocytes to the endothelium, thereby initiating atherogenesis. Potential interventions include the use of unsaturated long-chain fatty acids, polyphenols, antioxidants, angiotensin converting enzyme inhibitors and high-dose aspirin, which have direct anti-inflammatory and antiatherogenic effects. Furthermore, peroxisome proliferator activating receptor gamma (PPARgamma) agonists and statins have similar properties, which are in part independent of their lipid-lowering effects.

Therapeutic Potential of Oral Antiproliferative Agents in the Prevention of Coronary Restenosis

The treatment of coronary artery disease has reached many milestones - from balloon angioplasty to drug-eluting stents. The last decade witnessed the revolution of bare metal stents with new designs, alloys and strut thicknesses. Yet restenosis, the aphorismic 'Achilles heel', remains to be conquered. The restenosis rates with balloon angioplasty alone are 30-40% and are reduced to 20-30% with stents. Although intravascular brachytherapy proved to be a durable and safely used technique to treat in-stent restenosis, clinical event rates were not reduced to single digits.Drug-eluting stents are showing positive results in this direction, but it is too early to predict their efficacy in various subsets of lesions. With the increased usage of these stents, there are reports of problems such as late stent malapposition, subacute and late thromboses, and aneurysm formations due to the vessel toxicity associated with this method of treatment. Furthermore, when multivessel stenting is considered, the cost of drug-eluting stents is a significant problem given the fact that these are no longer 'zero restenosis' devices. There is a definite need for a simple, safe and durable solution to restenosis. Oral agents are an alternative delivery strategy that can target multiple coronary lesions, which are targets for catheter-based revascularisation with any approved metal stent and with potentially lower cost. Although oral agents have been an interesting option to treat restenosis and several agents have been tested in trials since the 1980s, the results were disappointing. The development of devices such as intravascular ultrasound has led to a greater understanding of restenosis mechanisms, and the focus on pathophysiological mechanisms, which centred mainly on platelets, growth factors and lipids, has changed to inflammation, endothelium and smooth muscle cell proliferation.Accordingly, the targets of pharmaceutical agents have shifted from platelets to cell cycle inhibition, smooth muscle cell proliferation and migration, synthesis of extra cellular matrix, and inflammatory mediators. Initial encouraging results with oral drugs such as cilostazol, sirolimus (rapamycin) and thiazolidinediones indicate a definite place for this strategy to reduce restenosis. A desirable oral agent would be anti-inflammatory, inhibit smooth muscle cell migration and proliferation, promote endothelial growth, and be well tolerated and free from significant adverse effects. It may be useful to start with a high loading dose before stent implantation and then follow with a short-term lower maintenance dose. Future trials should be aimed at finding an ideal agent, effective loading dose, maintenance dose and optimum duration of therapy.

Immunosuppressive Therapy for the Prevention of Restenosis after Coronary Artery Stent Implantation (IMPRESS Study)

OBJECTIVES

This study tested the effect of oral prednisone on clinical and angiographic restenosis rate after successful stent implantation in patients with persistent elevation of systemic markers of inflammation after the procedure.

BACKGROUND

Experimental studies have shown that corticosteroids have the potential to reduce the inflammatory response associated with stent implantation.

METHODS

Eighty-three patients undergoing successful stenting with C-reactive protein (CRP) levels >0.5 mg/dl 72 h after the procedure were randomized to receive oral prednisone or placebo for 45 days. The primary clinical end point was 12-month event-free survival rate (defined as freedom from death, from myocardial infarction, and from recurrence of symptoms requiring additional revascularization). The angiographic end points were restenosis rate and late loss at six months.

RESULTS

Twelve-month event-free survival rates were 93% and 65% in patients treated with prednisone and placebo, respectively (relative risk [RR] 0.18, 95% confidence intervals [CI], 0.05 to 0.61, p = 0.0063). Six-month restenosis rate and late loss were lower in prednisone-treated than in placebo-treated patients (7% vs. 33%, p = 0.001, and 0.39 +/- 0.6 mm vs. 0.85 +/- 0.6 mm, p = 0.001, respectively).

CONCLUSIONS

In patients with persistently high CRP levels after successful coronary artery stent implantation, oral immunosuppressive therapy with prednisone results in a striking reduction of clinical events and angiographic restenosis rate.

Drug-eluting stents: from bench to bed

The introduction of stents to clinical practice in 1987 was the major breakthrough in the field of percutaneous coronary intervention (PCI). The use of stenting has drastically improved the outcomes of traditional PCI. First stents were approved for bailout and treatment of dissections, reducing dramatically the need for emergent coronary artery bypass grafting (CABG) as a result of vessel closure during PCI. Later stents were proven to reduce the restenosis rate of PCI from 30%-40% with balloon angioplasty to 15%-20% with stents, primarily by eliminating elastic recoil and vascular remodeling as shown by intravascular ultrasound (IVUS) studies. These outcomes have led to a wide acceptance of stenting as the strategy of choice for more than 80% of all PCI procedures performed. The current review focuses on the following topics: (1) strategies in drug selection to reduce neointimal proliferation, (2) stent designs and polymer selection as a platform for drug-eluting stents, (3) review of major preclinical and clinical experimental work performed in the field, and (4) a discussion of the potential and limitations of the technology.

Tumor necrosis factor-alpha in cardiovascular biology and the potential role for anti-tumor necrosis factor-alpha therapy in heart disease

The functional role of tumor necrosis factor (TNF)-alpha in the heart has been extensively studied over the last 15 years. Collectively, these studies have demonstrated that TNF-alpha has both diverse and potentially conflicting roles in cardiac function and pathology. These include beneficial effects, such as cardioprotection against ischemia, myocarditis, and pressure overload, as well as potentially adverse effects, such as the development of atherosclerosis, reperfusion injury, hypertrophy, and heart failure. TNF-alpha antagonist therapy recently has been demonstrated to be clinically applicable in inflammatory conditions, and clinical trials are currently in progress in the use of these agents in cardiovascular diseases. The scope for clinical applications of anti-TNF-alpha therapy in cardiovascular diseases is potentially extensive. Hence, this review has been undertaken to evaluate the cardiovascular effects of this pleiotropic cytokine and to evaluate the potential of targeting this cytokine in cardiovascular therapeutics. An overview of the TNF-alpha peptide and its associated signaling are described. This is followed by a discussion of the known roles of TNF-alpha in cardiac physiology and in a diverse array of cardiac pathologies. Reference to experimental and clinical studies using anti-TNF-alpha therapies are described where applicable. The postulated role of TNF-alpha signaling concerning innate cardiac cellular processes that may have direct adaptive effects in the heart will be reviewed with respect to future research directions. Finally, the author postulates that attenuation of TNF-alpha biosynthesis in selected individuals will need to be tested if true benefits of this therapeutic approach are to be realized in the management of cardiovascular diseases.

Initial results of the Quanam drug eluting stent (QuaDS-QP-2) Registry (BARDDS) in human subjects

Thirty-two patients presenting with varied coronary syndromes and anatomy were treated with a new coronary multisleeve drug delivery coronary stent (QuaDS-QP-2) containing up to 4,000 microg of a taxol-derived lipophilic microtubule inhibitor (QP2). The device was successfully implanted in 32 patients who have been followed for up to 2 years. Twenty-five patients have undergone stress ECHO or SPECT Thallium and all are currently asymptomatic. Thirteen patients have already been restudied angiographically, by IVUS and/or by SPECT Thallium testing and are detailed in this report. Angiographic, IVUS, and SPECT Thallium have been controlled at a mean of 11.2 months (range, 6-15 months) in this 13-patient cohort. Although all 13 QuaDS-QP-2 (QDES) stents were angiographically and IVUS patent, two reinterventions have been required in the 32-patient study group thus far, both relate to either new disease or to distal, small-vessel disease beyond the stent. There was no evidence of significant proliferation in the QDES devices. On the basis of this preliminary data and a European pilot study, a controlled randomized trial (SCORE) is currently in progress in western Europe.

Risks and benefits of preoperative high dose methylprednisolone in surgical patients: a systematic review

BACKGROUND

A single preoperative high dose of methylprednisolone (15 to 30 mg/kg) has been advocated in surgery, because it may inhibit the surgical stress response and thereby improve postoperative outcome and convalescence. However, these potential clinical benefits must be weighed against possible adverse effects.

OBJECTIVE

To conduct a risk-benefit analysis using a meta-analysis, to compare complication rates and clinical advantages associated with the use of high dose methylprednisolone in surgical patients.

METHODS

Randomised controlled trials of high dose methylprednisolone in elective and trauma surgery were systematically searched for in various literature databases. Outcome data on adverse effects, postoperative pain and hospital stay were extracted and statistically pooled in fixed-effects meta-analyses.

RESULTS

We located 51 studies in elective cardiac and noncardiac surgery, as well as traumatology. Pooled data failed to show any significant increase in complication rates. In patients treated with corticosteroids, nonsignificantly more gastrointestinal bleeding and wound complications were observed; the 95% confidence interval boundaries of the numbers-needed-to-harm were 59 and 38, respectively. The only significant finding was a reduction of pulmonary complications (risk difference -3.5%; 95% confidence interval -1.0 to -6.1), mainly in trauma patients.

CONCLUSION

For patients undergoing surgical procedures, a perioperative single-shot administration of high dose methylprednisolone is not associated with a significant increase in the incidence of adverse effects. In patients with multiple fractures, limited evidence suggests promising benefits of glucocorticoids on pulmonary complications.