Coronary stenting and inflammation

Hypercholesterolemia exacerbates in-stent restenosis in rabbits: Studies of the mitigating effect of stent surface modification with a CD47-derived peptide

BACKGROUND AND AIMS

Hypercholesterolemia (HC) has previously been shown to augment the restenotic response in animal models and humans. However, the mechanistic aspects of in-stent restenosis (ISR) on a hypercholesterolemic background, including potential augmentation of systemic and local inflammation precipitated by HC, are not completely understood. CD47 is a transmembrane protein known to abort crucial inflammatory pathways. Our studies have examined the interrelation between HC, inflammation, and ISR and investigated the therapeutic potential of stents coated with a CD47-derived peptide (pepCD47) in the hypercholesterolemic rabbit model.

METHODS

PepCD47 was immobilized on metal foils and stents using polybisphosphonate coordination chemistry and pyridyldithio/thiol conjugation. Cytokine expression in buffy coat-derived cells cultured over bare metal (BM) and pepCD47-derivatized foils demonstrated an M2/M1 macrophage shift with pepCD47 coating. HC and normocholesterolemic (NC) rabbit cohorts underwent bilateral implantation of BM and pepCD47 stents (HC) or BM stents only (NC) in the iliac location.

RESULTS

A 40 % inhibition of cell attachment to pepCD47-modified compared to BM surfaces was observed. HC increased neointimal growth at 4 weeks post BM stenting. These untoward outcomes were mitigated in hypercholesterolemic rabbits treated with pepCD47-derivatized stents. Compared to NC animals, inflammatory cytokine immunopositivity and macrophage infiltration of peri-strut areas increased in HC animals and were attenuated in HC rabbits treated with pepCD47 stents.

CONCLUSIONS

Augmented inflammatory responses underlie severe ISR morphology in hypercholesterolemic rabbits. Blockage of initial platelet and leukocyte attachment to stent struts through CD47 functionalization of stents mitigates the pro-restenotic effects of hypercholesterolemia.

Gallic Acid Inhibits Proliferation and Migration of Smooth Muscle Cells in a Pig In-Stent Restenosis Model

In-stent restenosis (ISR) develops primarily due to neointimal hyperplasia. Gallic acid (GA) has anti-inflammatory, antioxidant, and cardioprotective effects. This study sought to investigate the effects of GA on neointimal hyperplasia and proliferation and migration of vascular smooth muscle cells (VSMCs) in a pig ISR model. In vitro proliferation and migration experiments were confirmed, after VSMCs were treated with platelet-derived growth factor (PDGF-BB) and GA (100 µM) using a 3-(4,5-dimethylthiazol)-2,5-diphenyltetrazolium bromide (MTT) assay and a scratch wound assay for 24 hours and 48 hours. A bare metal stent (BMS) was implanted in the pig coronary artery to induce ISR with overdilation (1.1-1.2:1), and GA (10 mg/kg/day) was administered for 4 weeks. At the 4-week follow-up, optical coherence tomography (OCT) and histopathological analyses were performed. GA decreased the proliferation of VSMCs by PDGF-BB for 24 hours (89.24±24.56% vs. 170.04±19.98%, p<0.001) and 48 hours (124.87±7.35% vs. 187.64±4.83%, p<0.001). GA inhibited the migration of VSMCs induced by PDGF-BB for 24 hours (26.73±2.38% vs. 65.38±9.73%, p<0.001) and 48 hours (32.96±3.04% vs. 77.04±10.07%, p<0.001). Using OCT, % neointimal hyperplasia was shown to have significantly decreased in the GA group compared with control vehicle group (28.25±10.07% vs. 37.60±10.84%, p<0.001). GA effectively reduced neointimal hyperplasia by inhibiting the proliferation and migration of VSMCs in a pig ISR model. GA could be a potential treatment strategy for reducing ISR after stent implantation.

Hif-1α/Slit2 Mediates Vascular Smooth Muscle Cell Phenotypic Changes in Restenosis of Bypass Grafts

Vascular smooth muscle cells (VSMCs) are involved in restenosis of bypass grafts and cause artery graft occlusion. This study aimed to explore the role of Slit2 in phenotypic switching of VSMCs and its effect on restenosis of vascular conduits. An animal model of vascular graft restenosis (VGR) was produced in SD rats and assessed by echocardiography. The expression of Slit2 and Hif-1α was measured in vivo and in vitro. After Slit2 overexpression, the migration and proliferation of VSMCs were detected in vitro, and the restenosis rates and phenotype of VSMCs were tested in vivo. The arteries of the VGR model presented significant stenosis, and Slit2 was decreased in VSMCs of the VGR model. In vitro, Slit2 overexpression inhibited the migration and proliferation of VSMCs, but Slit2 knockdown promoted migration and proliferation. Hypoxia induced Hif-1α but reduced Slit2, and Hif-1α negatively regulated Slit2 expression. Moreover, Slit2 overexpression weakened the rate of VGR and maintained the patency of artery bypass grafts, which suppressed the phenotypic switching of VSMCs. Slit2 inhibited the synthetic phenotype transformation to inhibit the migration and proliferation of VSMCs and delayed the VGR via Hif-1α.

Prognostic Value of High-Sensitivity C-Reactive Protein in In-Stent Restenosis: A Meta-Analysis of Clinical Trials

Background: A risk assessment of in-stent restenosis (ISR) patients is critical for providing adequate treatment. Nevertheless, the prognostic value of high-sensitivity CRP (hs-CRP) levels on ISR has not been consistently demonstrated in clinical studies. In the current meta-analysis, we aim to assess the predictive role of hs-CRP in patients treated with stenting. Methods: We searched PubMed, Web of Science, Embase, and the Cochrane Registry through May 2022. We selected random control trials that compared the effects of different interventions, and that revealed the effects of hs-CRP. Two reviewers independently screened the articles, extracted the data, and assessed the quality of the studies according to the PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). The data were pooled using a random-effects meta-analysis. Results: Nine articles were included in the meta-analysis. A total of 1.049 patients received stent implantation, and 185 ISR events were recorded during the 1–12-month follow-up period. Baseline hs-CRP levels were not associated with the prediction of ISR among patients receiving stent implantation. The OR of hs-CRP for ISR was 1.81 (0.92–2.69). In the subgroup analysis, 6–12-month hs-CRP levels, diabetes mellitus (DM), and age ≥60(years)were associated with a higher risk of ISR. Conclusions: This meta-analysis shows that higher levels of baseline hs-CRP are not associated with an increased risk of ISR in stented patients. However, an increased risk of ISR was associated with hs-CRP levels at 6 to 12 months of follow-up, which is higher in studies with diabetes mellitus patients and the elderly.

Myeloid PHD2 deficiency accelerates neointima formation via Hif-1α

The key players of the hypoxic response are the hypoxia-inducible factors (Hif), whose α-subunits are tightly regulated by Prolyl-4-hydroxylases (PHD), predominantly by PHD2. Monocytes/Macrophages are involved in atherosclerosis but also restenosis and were found at hypoxic and sites of the lesion. Little is known about the role of the myeloid PHD2 in atherosclerosis and neointima formation. The study aimed to investigate the consequences of a myeloid deficiency of PHD2 in the process of neointima formation using an arterial denudation model. LysM-cre mice were crossed with PHD2^fl/fl, PHD2^fl/fl/Hif1α^fl/fl and PHD2^fl/fl/Hif2α^fl/fl to get myeloid specific knockout of PHD2 and the Hif-α subunits. Denudation of the femoral artery was performed and animals were fed a western type diet afterwards with analysis of neointima formation 5 and 35 days after denudation. Increased neointima formation in myeloid PHD2 knockouts was observed, which was blunted by double-knockout of PHD2 and Hif1α whereas double knockout of PHD2 and Hif-2α showed comparable lesions to the PHD2 knockouts. Macrophage infiltration was comparable to the neointima formation, suggesting a more inflammatory reaction, and was accompanied by increased intimal VEGF-A expression. Collagen-content inversely correlated to the extent of neointima formation suggesting a destabilization of the plaque. This effect might be triggered by macrophage polarization. Therefore, in vitro results showed a distinct expression pattern in differentially polarized macrophages with high expression of Hif-1α, VEGF and MMP-1 in proinflammatory M1 macrophages. In conclusion, the results show that myeloid Hif-1α is involved in neointima hyperplasia. Our in vivo and in vitro data reveal a central role for this transcription factor in driving plaque-vascularization accompanied by matrix-degradation leading to plaque destabilization.

The Development of Design and Manufacture Techniques for Bioresorbable Coronary Artery Stents

Coronary artery disease (CAD) is the leading killer of humans worldwide. Bioresorbable polymeric stents have attracted a great deal of interest because they can treat CAD without producing long-term complications. Bioresorbable polymeric stents (BMSs) have undergone a sustainable revolution in terms of material processing, mechanical performance, biodegradability and manufacture techniques. Biodegradable polymers and copolymers have been widely studied as potential material candidates for bioresorbable stents. It is a great challenge to find a reasonable balance between the mechanical properties and degradation behavior of bioresorbable polymeric stents. Surface modification and drug-coating methods are generally used to improve biocompatibility and drug loading performance, which are decisive factors for the safety and efficacy of bioresorbable stents. Traditional stent manufacture techniques include etching, micro-electro discharge machining, electroforming, die-casting and laser cutting. The rapid development of 3D printing has brought continuous innovation and the wide application of biodegradable materials, which provides a novel technique for the additive manufacture of bioresorbable stents. This review aims to describe the problems regarding and the achievements of biodegradable stents from their birth to the present and discuss potential difficulties and challenges in the future.

Non-Invasive Treatment for Coronary In-Stent Restenosis via Wireless Revascularization With Nitinol Active Stent

This paper reports a novel shape memory alloy (SMA) nitinol type active stent for non-invasive restenosis treatment, which operates using a radiofrequency (RF) electro-thermo-mechanical actuation technique for wireless revascularization. The developed stent is equipped with a capacitive pressure sensor for in-artery blood pressure measurement and can provide multiple expansion to restore the blood pressure flow. The device design, working principle, fabrication, and characterization of the nitinol active stent are reported in this work. The wireless monitoring feature is achieved via peak shifting in the reflection coefficient of the S₁₁ parameter. The active stent with initial diameter and resonant frequency of 2 mm and 315 MHz, respectively, is expanded uniformly in stages up to 4.2 mm in diameter when excited with an RF power of ∼30 W for 320 s. The active stent is delivered and deployed ex vivo inside the left coronary artery of a cervine heart. The stented cervine heart before and after wireless actuation is inspected via penetration of X-rays. Endoscopic images reveal the expansion of the stent strut profile within the lumen of the stented artery. The active stent expands in stages up to 3.7 mm in diameter to scaffold the cervine coronary artery after excited with an RF power of 46.7 W. The achievable wireless revascularization capability eradicates the necessity of reintervention and repeat stenting procedure, whereas real-time wireless monitoring provides rapid indication of in-artery re-narrowing occurrence.

Immobilisation of an anti-platelet adhesion and anti-thrombotic drug (EP224283) on polydopamine coated vascular stent promoting anti-thrombogenic properties

Current vascular drug-eluting stents based on immuno-proliferative drugs would reduce the rate of in-stent restenosis (ISR) but may be associated with a higher risk of acute stent thrombosis due to non-selective activity. In this paper, we aimed to develop a polydopamine (PDA) coated chromium‑cobalt (CoCr) stent functionalised with EP224283 (Endotis Pharma SA), which combines both a GPIIbIIIa antagonist (tirofiban moiety) and a factor Xa inhibitor (idraparinux moiety) to reduce acute stent thrombosis. PDA-coated chromium‑cobalt (CoCr) samples were first immersed in a polyethylenimine (PEI, pH 8.5) solution to increase amine function density (36.0 ± 0.1 nmol/cm²) on the CoCr surface. In a second step, avidin was grafted onto CoCr-PDA-PEI through the biotin linkage (strategy 1) or directly by coupling reactions (strategy 2). The HABA titration proved the fixation of biotin onto CoCr-PDA-PEI surface with a density of 0.74 nmol/cm². The fixation of avidin was demonstrated by water contact angle (WCA) and surface plasmon resonance (SPR). SEM micrograph shows the flexibility of the thin layer coated onto the stent after balloon inflation. Independently of the strategy, a qualitative SEM analysis showed a reduction in platelet activation when the molecule EP224283 was immobilised on avidin. In parallel, the measurement of anticoagulant activity (anti-Xa) revealed a higher anti-factor Xa activity (2.24 IU/mL vs. 0.09 IU/mL in control) when EP224283 was immobilised on avidin. Interestingly, after seven days of degradation, the anticoagulant activity was persistent in both strategies and looked more important with the strategy 2 than in strategy 1. Throughout this work, we developed an innovative vascular stent through the immobilisation of EP224283 onto CoCr-PDA-PEI-(avidin) system, which provides a promising solution to reduce ISR and thrombosis after stent implantation.

The effect of fatty acids in red blood cell membranes on the dynamics of inflammatory markers following the coronary stent implantation

The effect of 20 fatty acids in erythrocyte cell membranes on the extent of inflammatory response and cell oxidative stress was evaluated using multidimensional statistical data analysis in 54 patients suffering from ischemic heart disease undergoing percutaneous coronary intervention with coronary stent implantation using multidimensional statistical data analysis. A systemic inflammatory response was indicated by an increase of C-reactive protein (CRP), serum amyloid A (SAA) and ceruloplasmin 48 h after stent implantation and by an increase of interleukin-6 (IL-6) 24 h after intervention. The increase of malondialdehyde (MDA) after 48 h was used as a marker of cell damage by oxidative stress. Multiple linear regression revealed statistically significant relationships between concentration of some fatty acids and the magnitude of inflammatory response, or oxidative stress, after stent implantation. The most significant relationship with an increase of plasma CRP was found for myristic acid and, to a lesser extent, for oleic acid. Trans octadecenoic acid, and to a lesser extent palmitooleic and nervonic fatty acids were found in inverse correlation with the CRP increase. The increase of IL-6 showed a statistically significant correlation with myristic acid, to a lesser extent with cis-9-eicosenoic acid and to the least extent with docosahexaenoic acid, inversely with pentadecanoic, γ-linolenic and stearic acids. An increase of oxidative stress (MDA) significantly correlated only with γ-linolenic acid. Other studied markers of inflammatory response to coronary stenting were SAA and ceruloplasmin (Cp). Statistical evaluation revealed that SAA and Cp are not suitable markers for assessment relationships between inflammation and erythrocyte membrane fatty acids.

Epicardial fat thickness correlates with coronary in-stent restenosis in patients with acute myocardial infarction

OBJECTIVE

To determine the relation between epicardial fat thickness and coronary in-stent restenosis in patients with acute myocardial infarction and percutaneous coronary intervention.

METHODS

A prospective study was conducted, which included 129 patients (67.3% male, mean age 62.9±10 years) with ST segment elevation acute myocardial infarction undergoing primary percutaneous coronary intervention with bare metal stent. Patients were divided in two groups according to the presence (n=21) or not (n=108) of in-stent restenosis during one year follow-up.

RESULTS

Epicardial fat was significantly thicker in patients with coronary in-stent restenosis (5.51±1.6 vs 4.14±2.0mm, p=0.006). A proportionally and significantly thicker epicardial fat was found according to the increase in coronary disease severity (3.3±0.9mm vs 4.3±1.8mm vs 4.7±2.3mm vs 6.7±2.2mm, for type A, B1, B2 and C lesions, respectively, p=0.001) and number of vessels (3.07±1.2mm vs 4.92±1.8mm vs 5.43±2.2mm, for one, two and three vessels disease, respectively, p<0.0001). Epicardial fat thickness ≥4.7mm had 75.0% sensibility and 69.0% specificity for predicting restenosis (AUC=0.737).

CONCLUSIONS

Echocardiographic evaluation of epicardial fat thickness could identify those patients with acute myocardial infarction with greater probabilities of in-stent restenosis after percutaneous coronary intervention.

Incorporation of a Ligand Peptide for Immune Inhibitory Receptor LAIR-1 on Biomaterial Surfaces Inhibits Macrophage Inflammatory Responses

Leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1) is an inhibitory receptor broadly expressed on immune cells, with its ligands residing within the extracellular matrix protein collagen. In this study, surfaces are modified with a LAIR-1 ligand peptide (LP), and it is observed that macrophages cultured on LAIR-1 LP-conjugated surfaces exhibit significantly reduced secretion of inflammatory cytokines in response to proinflammatory stimuli that reflect an injured environment. These downregulated mediators include TNF-α, MIP-1α, MIP-1β, MIP-2, RANTES, and MIG. Knockdown of LAIR-1 using siRNA abrogates this inhibition of cytokine secretion, supporting the specificity of the inhibitory effect to this receptor. These results are the first to demonstrate that integration of LAIR-1 ligands with biomaterials could suppress inflammatory responses.

Plasma activated coating immobilizes apolipoprotein A-I to stainless steel surfaces in its bioactive form and enhances biocompatibility

We utilized a plasma activated coating (PAC) to covalently bind the active component of high density lipoproteins (HDL), apolipoprotein (apo) A-I, to stainless steel (SS) surfaces. ApoA-I suppresses restenosis and thrombosis and may therefore improve SS stent biocompatibility. PAC-coated SS significantly increased the covalent attachment of apoA-I, compared to SS alone. In static and dynamic flow thrombosis assays, PAC+apoA-I inhibited thrombosis and reduced platelet activation marker p-selectin. PAC+apoA-I reduced smooth muscle cell attachment and proliferation, and augmented EC attachment to PAC. We then coated PAC onto murine SS stents and found it did not peel or delaminate following crimping/expansion. ApoA-I was immobilized onto PAC-SS stents and was retained as a monolayer when exposed to pulsatile flow in vivo in a murine stent model. In conclusion, ApoA-I immobilized on PAC withstands pulsatile flow in vivo and retains its bioactivity, exhibiting anti-thrombotic and anti-restenotic properties, demonstrating the potential to improve stent biocompatibility.

Th1, Th17, CXCL16 and homocysteine elevated after intracranial and cervical stent implantation

The presence of Th1 and Th17 cells has been observed as major inducers in inflammation and immune responses associated stenting. However, there is rare data on the impact of Th1, Th17, CXCL16 and homocysteine after cerebral stent implantation. Here, we performed the statistical analysis to first evaluate the variation of the Th17and Th1 cells and their related cytokines, CXCL16 and homocysteine in the peripheral blood of patients with cerebral stenting. The flow cytometry was used to detect the proportion of Th1 and Th17 cells in peripheral blood mononuclear cells (PBMCs). The enzyme-linked immunosorbent assay was used to measure the serum concentrations of IFN-γ, IL-17 and CXCL16. Plasma homocysteine was examined by immunoturbidimetry. The level of Th1, CXCL16 and homocysteine showed an increase at 3 d, followed by the continuous decrease at 7 d and 3 months. The frequency of Th17 cells increased to a peak at three days, and subsequently decreased with a higher level than baseline. Our data revealed that the variation in Th1, Th17, CXCL16 and homocysteine in peripheral blood of patients with stenting may be implicated in inflammation after intracranial and cervical stent implantation. A better understanding of these factors will provide help for further drug design and clinical therapy.

Plasma microRNAs as potential noninvasive biomarkers for in-stent restenosis

OBJECTIVE

To investigate whether microRNAs (miRs) can serve as novel biomarkers for in-stent restenosis (ISR).

METHODS

This retrospective, observational single-centre study was conducted at the cardiovascular department of a tertiary hospital centre in the north of China. Follow-up coronary angiography at 6 to 12 months was performed in 181 consecutive patients implanted with drug-eluting stents. Fifty-two healthy volunteers served as the control group. The plasma miRs levels were analyzed by quantitative real-time PCR. Receiver-operating characteristic curve (ROC) analysis was performed to investigate the characters of these miRs as potential biomarkers of ISR.

RESULTS

MiR-21 levels in ISR patients were significantly higher than those in non-ISR patients and healthy controls (P<0.05), while miR-100 (P<0.05), miR-143 (P<0.001) and miR-145 (P<0.0001) levels were significantly decreased in ISR patients. Further analysis showed that miR-21 levels were remarkably increased (P = 0.045), while miR-100 (P = 0.041), miR-143 (P = 0.029) and miR-145 (P<0.01) levels were dramatically decreased in patients with diffuse ISR compared to those with focal ISR. ROC analysis demonstrated that the area under curve of miR-145, miR-143, miR-100 and miR-21 were 0.880 (95% confidence interval; CI = 0.791-0.987, P<0.001), 0.818 (95% confidence interval; CI = 0.755-0.963, P<0.001), 0.608 (95% confidence interval; CI = 0.372-0.757, P<0.05) and 0.568 (95% confidence interval; CI = 0.372-0.757, P<0.05), with specificity of 83.1%, 80.1%, 68.9% and 68.6%, and sensitivity of 88.7%, 82.1%, 60.2% and 50.1%, respectively.

CONCLUSIONS

Circulating miR-143 and miR-145 levels are associated with the occurrence of ISR and can serve as novel noninvasive biomarkers for ISR.

Local inhibition of hypoxia-inducible factor reduces neointima formation after arterial injury in ApoE-/- mice

OBJECTIVE

Hypoxia plays a pivotal role in development and progression of restenosis after vascular injury. Under hypoxic conditions the hypoxia-inducible factors (HIFs) are the most important transcription factors for the adaption to reduced oxygen supply. Therefore the aim of the study was to investigate the effect of a local HIF-inhibition and overexpression on atherosclerotic plaque development in a murine vascular injury model.

METHODS AND RESULTS

After wire-induced vascular injury in ApoE-/- mice a transient, local inhibition of HIF as well as an overexpression approach of the different HIF-subunits (HIF-1α, HIF-2α) by adenoviral infection was performed. The local inhibition of the HIF-pathway using a dominant-negative mutant dramatically reduced the extent of neointima formation. The diminished plaque size was associated with decreased expression of the well-known HIF-target genes vascular endothelial growth factor-A (VEGF-A) and its receptors Flt-1 and Flk-1. In contrast, the local overexpression of HIF-1α and HIF-2α further increased the plaque size after wire-induced vascular injury.

CONCLUSIONS

Local HIF-inhibition decreases and HIF-α overexpression increases the injury induced neointima formation. These findings provide new insight into the pathogenesis of atherosclerosis and may lead to new therapeutic options for the treatment of in stent restenosis.

BioMatrix®Biolimus A9®-eluting coronary stent: a next-generation drug-eluting stent for coronary artery disease

Drug-eluting stent technology consisting of a bare metal stent, carrier coating, bioactive drug and delivery system, offers an almost infinite range of possible device configurations. A growing understanding of the mechanisms of restenosis allows for the design of synergistic functions within these components, thus providing a basis for new and improved products. The BioMatrix stent (Biosensors Interventional Technologies Pte Ltd., Singapore) elutes the new sirolimus derivative Biolimus A9 from a biodegradable polylactic acid polymer. Biolimus A9 possesses enhanced anti-inflammatory and antiproliferative activity with an improved pharmacokinetic profile. Permanent polymer-carrier-based platforms may be associated with inflammation, late thrombosis and restenosis. The BioMatrix, with its asymmetric and abluminal coating, releases Biolimus A9 into the vessel wall while the polylactic acid polymer is resorbed by surrounding tissues. Clinical studies have demonstrated the BioMatrix to be well tolerated and effective, and it has now become the subject of an aggressive clinical program.

The role of monocyte phenotype switching in peri-procedural myocardial injury and its involvement in statin therapy

Peri-procedural myocardial injury, which is associated with worse long-term clinical outcome, is a common complication related to inflammatory pathogenetic mechanisms. Monocytes and macrophages play key roles in the initiation and progression of atherosclerosis. Recent studies have demonstrated that monocytes in human peripheral blood are heterogeneous, including CD14⁺CD16⁻ monocytes and CD14⁺CD16⁺ monocytes. Several lines of evidence suggested that CD14⁺CD16⁺ monocytes might contribute to the accelerated atherosclerosis. In view of the heightened appreciation of the heterogeneity of circulating monocytes, we hypothesized that an up-shifting subset of CD14⁺CD16⁺ monocytes might be induced by percutaneous coronary intervention (PCI), which subsequently leads to peri-procedural myocardial injury. Moreover, statins loading before PCI could exert anti-inflammatory effects partly by modulating monocyte phenotype and thus prevent peri-procedural myocardial injury.

Anti-inflammatory effects of arsenic trioxide eluting stents in a porcine coronary model

Previous research from our group has demonstrated arsenic trioxide eluting stents significantly reduced neointimal area and thickness compared with bare metal stents. In the present study, the anti-inflammatory effects of arsenic trioxide in vitro and arsenic trioxide eluting stents in a porcine coronary model have been explored. Sixty-five pigs underwent placement of 139 oversized stents in the coronary arteries with histologic analysis, endothelial function analysis, and immunohistochemical and western blot analyses. Arsenic trioxide eluting stents effectively inhibited local inflammatory reactions, while no significant difference in endothelialization and endothelial function between arsenic trioxide eluting stents and bare metal stents was observed. Arsenic trioxide eluting stents favorably modulate neointimal formation due to less augmentation of early inflammatory reactions, and quick endothelialization of the stent surface, which might contribute to long-term safety and efficacy of drug eluting stents.

Urinary trypsin inhibitor reduced inflammatory response after stent injury in minipig

This study investigated whether urinary trypsin inhibitor (UTI) inhibits neointimal formation by reducing inflammatory response after stent injury. Twenty minipigs having undergone oversized bare material stent implantation in the left anterior descending artery were randomly subdivided into two groups: a UTI group (n=10) and a control group (n=10). Two systemic markers of inflammation (serum macrophage chemoattractant protein-1 and interleukin-6 levels measured by ELISA) were increased after stent implantation, and two days after stem implantation, their levels were positively correlated with the maximal percentage of area stenosis on day 28 (r(2)=0.889 and 0.743, respectively). This effect was abolished by UTI administration. Twenty-eight days after implantation, morphometric analysis of the stented arteries revealed significantly reduced luminal stenosis (38±6% vs. 64±12%, P<0.05), a neointimal area (3.22±0.57 mm(2) vs. 5.21±1.04 mm(2), P<0.05), neointimal thickness (0.31±0.13 mm vs. 0.46±0.16 mm, P<0.05), and an inflammatory score of 1.02±0.05 vs. 1.30±0.08 in UTI-treated animals as compared with controls. Twenty-eight days after stenting, arterial nuclear factor-κB expression was 36.93±7.16% in all of the cells in controls and 23.32±4.54% in UTI-treated minipigs. UTI could reduce neointimal formation after stenting by inhibiting the local and the systemic inflammatory response. Percutaneous coronary intervention could benefit from precocious anti-inflammatory treatment.

Eosinophilic responses to stent implantation and the risk of Kounis hypersensitivity associated coronary syndrome

The use of drug eluting stents constitutes a major breakthrough in current interventional cardiology because it is more than halves the need of repeat interventions. It is incontrovertible that coronary stents, in general, have been beneficial for the vast majority of patients. A small increase in thrombosis, following DES implantation, is offset by a diminished risk of complications associated with repeat vascularization. However, late and, especially, very late stent thrombosis is a much feared complication because it is associated with myocardial infarction with increased mortality. Despite that stent thrombosis is thought to be multifactorial, so far clinical reports and reported pathology findings in patients died from coronary stent thrombosis as well as animal studies and experiments, point toward a hypersensitivity inflammation. The stented and thrombotic areas are infiltrated by interacting, via bidirectional stimuli inflammatory cells including eosinophils, macrophages, T-cells and mast cells. Stented regions constitute an ideal surrounding for endothelial damage and dysfunction, together with hemorheologic changes and turbulence as well as platelet dysfunction, coagulation and fibrinolytic disturbances. Drug eluting stent components include the metal strut which contains nickel, chromium, manganese, titanium, molybdenum, the polymer coating and the impregnated drugs which for the first generation stents are: the antimicrotubule antineoplastic agent paclitaxel and the anti-inflammatory, immunosuppressive and antiproliferative agent sirolimus. The newer stents which are called cobalt-chromiun stents and elute the sirolimus analogs everolimus and zotarolimus both contain nickel and other metals. All these components constitute an antigenic complex inside the coronary arteries which apply chronic, continuous, repetitive and persistent inflammatory action capable to induced Kounis syndrome and stent thrombosis. Allergic inflammation goes through three phases, the early phase, the late phase and the chronic phase and these three phases correspond temporally with early (acute and sub acute), late and very late stent thrombosis. Bioabsorbable allergy free poly lactic acid self expanding stents, nickel free stainless steel materials, stent coverage with nitric oxide donors and antibodies with endothelial progenitor cell capturing abilities as well as stents eluting anti-inflammatory and anti-allergic agents might be the solution of this so feared and devastating stent complication.

In vivo evaluation of a novel dexamethasone-heparin-double-coated stent for inhibition of artery restenosis and thrombosis

To evaluate the efficacy and safety of dexamethasone-heparin-double-coated stent (DHDCS) on inhibition of artery lumen reduction and neointimal hyperplasia in porcine model we carried out this study. Bare mental stents (BMS, n = 12), protein-coated stents (PCS, n = 12), heparin microballoon-coated stents (HMCS, n = 12), and DHDCS (n = 12), prepared by the spray drying method, were implanted into the selected internal iliac artery, external iliac artery, sacrococcygeal artery, and femoral artery of each of the selected pigs (n = 12), which were randomly divided into four groups on average. Thirty days and ninety days after the implantation, aorta angiography was performed on all the 12 mini-pigs to evaluate the artery lumen reduction. Subsequently, in order to analyze their histological appearance, the pigs were killed, and their arteries with the stents inside were taken out, embedded in plastic for hard histological section and hematoxylin-eosin (H.E.) staining, and examined by light microscopy and scanning electron microscopy (SEM). The artery lumen reduction and average neointimal hyperplasia in the group of DHDCS were significantly lesser than those in the other three groups of BMS, PCS, and HMCS. This study shows that DHDCS is capable of inhibiting the proliferation of intima and lumen area reduction of the target artery within stents, and effectively and safely reducing the incidence of regional thrombosis and restenosis for a short term.

Stents and statins: history, clinical outcomes and mechanisms

The 1980s witnessed the inception of both stents and 3-hydroxy-3-methyl-glutaryl-CoA reductase inhibitors (statins). While they evolved separately, it was soon realized that they each offered a unique and powerful mechanism for targeting the major offender in cardiovascular disease, namely atherosclerosis. Coincidentally, the first statin was approved by the US FDA in 1987, the same year that the coronary stent was conceived. Since that time, stents and statins have revolutionized the field of cardiovascular medicine and their paths have been intertwined. Several pivotal randomized clinical trials have established statins as an effective therapy for improving clinical outcomes after percutaneous coronary intervention (PCI) among patients presenting with stable coronary artery disease and acute coronary syndromes. In addition, chronic statin therapy and acute loading of statins prior to PCI has consistently been shown to limit periprocedural myocardial necrosis. The mechanism for improved clinical outcomes with statins has clearly been associated with statin-induced reductions in LDL. In addition, statins may also exert 'pleiotropic' effects, independent of LDL lowering, that might counteract the inflammatory and prothrombotic mileu created with PCI. This article provides a brief historical perspective of the evolution of the use of statins and stents in patients with coronary artery disease, an evaluation of the available clinical data supporting the use of statins in patients undergoing PCI across a wide spectrum of clinical scenarios, and a discussion of the potential mechanisms of the benefit of statins in these patients.

Preclinical Models of Restenosis and Their Application in the Evaluation of Drug-Eluting Stent Systems

Coronary arterial disease (CAD) is the leading cause of death in the United States, the European Union, and Canada. Percutaneous coronary intervention (PCI) has revolutionized the treatment of CAD, and it is the advent of drug-eluting stent (DES) systems that has effectively allayed much of the challenge of restenosis that has plagued the success of PCI through its 30-year history. However, DES systems have not been a panacea: There yet remain the challenges associated with interventions involving bare metallic stents as well as newly arisen concerns related to the application of DES systems. To effectively address these novel and ongoing issues, animal models are relied on both to project the safety and efficacy of endovascular devices and to provide insight into the pathophysiology underlying the vascular response to injury and mechanisms of restenosis. In this review, preclinical models of restenosis are presented, and their application and limitation in the evaluation of device-based interventional technologies for the treatment of CAD are discussed.

Incidence of moderate to severe cognitive dysfunction in patients treated with carotid artery stenting

OBJECTIVE

Approximately 25% of patients with carotid artery stenosis treated with carotid endarterectomy develop cognitive dysfunction (CD) between 1 day and 1 month after surgery compared with a control group. We hypothesized that patients with carotid artery stenosis treated with carotid artery stenting (CAS) performed under cerebral embolic protection also develop CD at similar time points compared with a control group.

METHODS

Twenty-four patients scheduled for elective CAS were enrolled in a prospective institutional review board-approved study to evaluate cognitive function with a battery of 6 neuropsychometric tests before, and 1 day and 1 month after, CAS. Test performance was compared with 23 patients undergoing coronary artery procedures (control group). The mean and standard deviation of the difference scores in the control group were used to generate Z scores. We used a previously described point system to transform negative Z scores into injury points for each neuropsychometric test. Global performance is presented as average deficit score (sum of injury points divided by the number of completed tests). All patients underwent the procedures with mild sedation. Results were analyzed in 2 ways: group-rate and event-rate analysis. Outcome was dichotomized by defining moderate to severe CD as average deficit score at least 1.5 standard deviations worse than the control group. Fisher tests and multivariate logistic regression models were used to analyze group performance.

RESULTS

Control patients tended to be younger and had a lower incidence of stroke or previous transient ischemic attack. One day after surgery, 41% of patients (10 of 24) treated with CAS developed moderate to severe CD (P = 0.0422). Average deficit score was also significantly higher in the CAS group at 1 day (P = 0.0265). These differences were independent of age and history of stroke/transient ischemic attack. Interestingly, we found that the absence of oral statin medication may increase the probability of CD. By 1 month, 9% of patients (1 of 11) treated with CAS presented with CD. Other patients were lost to follow-up.

CONCLUSION

CAS is associated with a decline in cognitive performance that is at least moderate 1 day after surgery.

Coronary stenting is associated with an acute increase in plasma myeloperoxidase in stable angina patients but not in patients with acute myocardial infarction

BACKGROUND

Myeloperoxidase (MPO) has emerged as a critical mediator in the physiopathology of atherosclerosis from plaque formation and growth until destabilization and rupture leading to acute coronary syndrome (ACS). Using coronary stenting as a model of plaque injury, we aimed to determine the evolution of systemic MPO levels following coronary stenting in stable angina patients and in patients with acute myocardial infarction (AMI).

METHODS

Plasma levels of MPO, lactoferrin, interleukin (IL)-6, C-reactive protein and PMN counts were assessed in 13 patients with Non-ST-elevation myocardial infarction (NSTEMI) (Group A) and in 29 patients with stable angina pectoris (Group B), undergoing coronary stenting. Serial blood samples were taken before angioplasty (baseline) and at 1, 6 and 24 h following initial balloon inflation.

RESULTS

Following angioplasty, the overall plasma MPO levels significantly increased at 1 h in group B (120.5+/-79.0 to 166+/-79.5, p=0.003) but not in group A (121+/-63.4 to 124.7+/-76.9, p=0.753). In Group B, the increase in MPO levels at 1 h were significantly higher in the presence of complex lesions compared to patients with simple lesions (p=0.023). Lactoferrin levels showed no change over time except for a significant decrease at 6 h in group B.

CONCLUSIONS

In stable angina patients, coronary stenting is associated with an acute and transient increase in plasma MPO levels, but not in lactoferrin levels, with an enhanced response in the presence of complex lesions. In contrast, we observed no changes in plasma MPO and lactoferrin levels following stenting in patients with AMI. Given its pro-inflammatory properties, the potential implication of MPO release on clinical outcome in stable patients undergoing stenting needs further investigation.

Drug releasing systems in cardiovascular tissue engineering

Heart disease and atherosclerosis are the leading causes of morbidity and mortality worldwide. The lack of suitable autologous grafts has produced a need for artificial grafts; however, current artificial grafts carry significant limitations, including thrombosis, infection, limited durability and the inability to grow. Tissue engineering of blood vessels, cardiovascular structures and whole organs is a promising approach for creating replacement tissues to repair congenital defects and/or diseased tissues. In an attempt to surmount the shortcomings of artificial grafts, tissue-engineered cardiovascular graft (TECVG), constructs obtained using cultured autologous vascular cells seeded onto a synthetic biodegradable polymer scaffold, have been developed. Autologous TECVGs have the potential advantages of growth, durability, resistance to infection, and freedom from problems of rejection, thrombogenicity and donor scarcity. Moreover polymers engrafted with growth factors, cytokines, drugs have been developed allowing drug-releasing systems capable of focused and localized delivery of molecules depending on the environmental requirements and the milieu in which the scaffold is placed. A broad range of applications for compound-releasing, tissue-engineered grafts have been suggested ranging from drug delivery to gene therapy. This review will describe advances in the development of drug-delivery systems for cardiovascular applications focusing on the manufacturing techniques and on the compounds delivered by these systems to date.

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.

Comparison of changes in early inflammatory markers between sirolimus- and paclitaxel-eluting stent implantation

BACKGROUND

Systemic inflammation after coronary intervention identifies patients at increased risk of subsequent cardiac events. Cardiac events, especially in-stent restenosis, are less frequent after use of sirolimus-eluting stent (SES) compared with paclitaxel-eluting stent (PES). However, the underlying mechanism for this disparity is not well investigated. We hypothesize that an attenuated inflammatory response after SES implantation may be a contributor.

PURPOSE

In the present study, we sought to determine the early inflammatory response after SES implantation in patients with single-vessel disease compared with PES implantation, and evaluate the relationship between inflammatory response and late clinical outcomes in a randomized design.

METHODS

Thirty-two patients with stable angina were randomly enrolled into the two groups, SES or PSE group (n = 16 respectively). Peripheral blood samples were taken before PCI, 24 and 72 h after stenting. The plasma concentrations of C-reactive protein (CRP) and interleukin-6 (IL-6) were determined by enzyme-linked immunosorbent assay (ELISA). The clinical and angiographic follow-up was performed at 8 months after stenting.

RESULTS

The data showed that there was no significant difference in clinical and angiographic baseline characteristics between the two groups. The plasma CRP and IL-6 levels at 24 h after stenting were significant higher in both groups compared with baseline (p < 0.01 respectively). Likewise, the CRP levels at 72 h after stenting were also significant higher compared with baseline in both groups (p < 0.01 respectively). However, the plasma levels of IL-6 at 24 h and CRP at 72 h after stenting were higher in PES group compared with SES group (p < 0.05). At 8 months follow-up, the rates of major adverse cardiac events, target lesion revascularization, in-stent and in-segment restenosis were similar in both groups. However, the late loss in both in-stent and in-segment was significantly higher in the PES group than in SES group (p < 0.001 respectively).

CONCLUSIONS

Our findings suggest that a drug-eluting stent implantation could trigger a systemic inflammatory response as previously demonstrated. However, SES implantation results in a lower inflammatory response compared with PES implantation, which seems to be associated with greater late of in-stent and in-segment loss at 8-month follow-up with PES.

A review of the biocompatibility of implantable devices: current challenges to overcome foreign body response

In recent years, a variety of devices (drug-eluting stents, artificial organs, biosensors, catheters, scaffolds for tissue engineering, heart valves, etc.) have been developed for implantation into patients. However, when such devices are implanted into the body, the body can react to these in a number of different ways. These reactions can result in an unexpected risk for patients. Therefore, it is important to assess and optimize the biocompatibility of implantable devices. To date, numerous strategies have been investigated to overcome body reactions induced by the implantation of devices. This review focuses on the foreign body response and the approaches that have been taken to overcome this. The biological response following device implantation and the methods for biocompatibility evaluation are summarized. Then the risks of implantable devices and the challenges to overcome these problems are introduced. Specifically, the challenges used to overcome the functional loss of glucose sensors, restenosis after stent implantation, and calcification induced by implantable devices are discussed.

Effects of coronary prestenting platelet inhibition on coronary poststenting inflammation

The aim of this study was to analyze the effect of 2 antiplatelet regimens on the inhibition of GP IIb/IIIa-dependent platelet activation and their association with the poststenting inflammatory response. Seventeen patients with acute myocardial infarction were divided into 2 groups: (A) clopidogrel plus tirofiban infusion administered together during inclusion (n = 10); (B) clopidogrel administered at inclusion and followed 2 hours after by tirofiban (n = 7). Blood samples were obtained at inclusion and at 24 and 48 hours after stenting. Before stenting, a greater reduction of GP IIb/IIIa-dependent platelet activation was found in both groups, although it was greater in group A than in group B. This statistical difference was not observed at 24 and 48 hours after the procedure. At 48 hours after stenting, interleukin-6, interleukin-10, soluble intracellular adhesion molecule-1, and soluble CD40 ligand plasma values were not different between experimental groups. By proteomics, different isoforms of the following proteins were identified: alpha 1-antitrypsin (ATT-1), fibrinogen gamma chain, apolipoprotein A-IV, apolipoprotein A-I, vitamin D binding protein, haptoglobin, and serotransferrin. At 48 hours after stenting, only the plasma expression of the ATT-1 isoform 5 was significantly increased in group A compared with group B. In conclusion, a greater inhibition of GP IIb/IIIa-dependent platelet activation before stenting was not correlated with a different inflammatory activity early after stenting.

Randomized comparison of early inflammatory response after sirolimus-eluting stent vs bare metal stent implantation in native coronary lesions

BACKGROUND

The clinical significance of early inflammatory response after coronary stent implantation has been controversial. Sirolimus-eluting stent (SES) has been shown to be better outcomes compared with bare metal stent (BMS). We prospectively investigated the early inflammatory response after SES or BMS implantation in patients with single-vessel lesion, and evaluated the relationship between inflammation and late clinical outcomes in a randomized design.

METHODS

Forty-eight patients with single-vessel disease were randomized into SES or BMS implantation group (n=24 respectively). Blood samples were taken before stenting, 1 h, 24 h and 8 months afterward. The plasma concentrations of C-reactive protein (CRP) and interleukin-6 (IL-6) were determined by ELISA. The clinical and angiographic follow-up were performed at 8 months after stenting.

RESULTS

There was no difference in baseline characteristics, plasma CRP and IL-6 concentrations between the 2 groups. However, plasma IL-6 concentrations at 1 h after stenting were higher in both groups than in baseline (p<0.01). In addition, the plasma CRP and IL-6 concentrations at 24 h after stenting were significantly higher in both groups compared with baseline (p<0.01 respectively). Likewise, plasma CRP and IL-6 concentrations were significantly higher in BMS group compared with SES group at 24 h after stenting (p<0.05 respectively). At the follow-up (mean 8 months after stenting), the rate of in-stent restenosis (ISR) and target lesion revascularization (TLR) were higher in BMS group than in SES group (p<0.05 respectively) although the plasma CRP and IL-6 concentrations are similar between the groups.

CONCLUSIONS

Single coronary stenting could trigger an early inflammatory response. However, patients undergoing SES implantation has less augmentation of early inflammatory markers after stenting compared to patients treated with BMS, which was positively related the incidence of ISR and TLR at follow-up. This may reflect the potential impact of SES implantation on the early inflammatory response and late clinical outcomes.

X-ray micro-tomography of a coronary stent deployed in a model artery

Coronary stents are small scaffolds routinely implanted during angioplasty procedures to re-open coronary arteries which have become narrowed by an atherosclerotic plaque. Despite the advent of drug-eluting stents to reduce restenosis (re-narrowing) after the procedure, complications still arise and mechanical factors may be partly the cause. Stents are being used in increasingly complex cases, so new forms of pre-clinical testing may be helpful in evaluating stent designs and deployment techniques. With this in mind, an in vitro experiment was conducted to evaluate the use of X-ray micro-tomography to image stents at various stages of deployment. A stent was deployed in an artificial artery while using a synchrotron X-ray source to obtain the tomography scans. A volume element (voxel) size of 5.3 microm was achieved, with a vertical field of view of 4.5mm. The imaging of the stent and artificial artery materials was better than expected, despite some attenuation artifacts and the high monochromatic beam energy used (25 keV). Experimental problems are discussed, together with recommendations for improving the technique. It is intended that this technique will be of interest to engineers and clinicians as a pre-clinical test.

Serum C-reactive protein response to percutaneous coronary intervention in patients with unstable or stable angina pectoris is associated with the risk of clinical restenosis

BACKGROUND

Inflammation plays a pivotal role in the pathogenesis of atherosclerosis. Previous reports have used vaccination as a model to stimulate inflammation. The aim of the present study was to investigate the role of C-reactive protein response to PCI in the risk of clinical restenosis or new coronary stenosis, considering PCI as a model to stimulate inflammation.

MATERIAL AND METHODS

Eight hundred and ninety-one patients with stable or unstable angina pectoris and with normal serum troponin T<or=0.03 microg/L before PCI were investigated. The survivors after a follow-up period of 2.6 years (850 patients) were included. Serum CRP and troponin T concentration were measured before and the day after PCI. Restenosis and new coronary stenosis, detected by coronary angiography due to symptomatic coronary heart disease, were determined.

RESULTS

CRP response to PCI, unstable angina pectoris, the number of vessels dilated and lack of stent implantation were associated with restenosis or new coronary stenosis. In multivariate analysis, patients in the highest tertile of CRP, induced by PCI, had an increased risk (risk ratio 1.7 [95% CI 1.1-2.9]) for restenosis or new coronary stenosis. Furthermore, patients with restenosis had an increased CRP response to PCI compared with those with new coronary stenosis.

CONCLUSION

The CRP response to PCI, as a model to stimulate inflammation, is associated with an increased risk of clinical restenosis. The results emphasize the role of CRP in the pathogenesis of coronary artery disease progression and in particular restenosis.

Need for a paradigm shift in cancer prevention and clinical oncology

Every year approximately 3 million Europeans develop a cancer. Of these patients, 20-25% will suffer from cancer of the hepatogastrointestinal tract (the largest cancer group) and most of these individuals will die from the disease. Recent analysis from the American Cancer Society indicates that disease-related mortality from heart, cerebrovascular and infectious disease has decreased dramatically in the last 60 years, whereas the mortality of cancer remains unchanged. Despite recent improvements in the understanding of the biology, development and progression of human cancers, and the development of novel diagnostic and therapeutic approaches, most cancer patients are diagnosed in an advanced stage with a limited chance of cure. We hypothesize that there has been a dramatic shift in the treatment and, more importantly, prevention of heart, cerebrovascular and infectious diseases that has not yet reached oncology practice. We think that the shift from local to systemic therapy in combination with biomarker-guided detection of patients at risk leads to a reversion of current medical management: we do not treat the end-stage disease but rather follow the course of cancer development starting with risk assessment, followed by disease treatment and prevention of disease progression. Thus, we can prevent end-stage disease that cannot be treated curatively. Our two-step hypothesis should lead to a dramatic improvement of the prognosis of cancer patients.

Leukocyte activation after coronary stenting in patients during the subacute phase of a previous ST-elevation myocardial infarction

OBJECTIVE

To study leukocyte activation after percutaneous coronary intervention in patients with previous ST elevation myocardial infarction.

METHODS

Neutrophil and monocyte activation (by flow cytometric assessment of the surface expression of CD11b and CD62L adhesion molecules) was assessed in 39 patients during the subacute period of a previous ST elevation myocardial infarction initially treated with fibrinolytic agents, before and after diagnostic coronary angiography (coronary angiography control phase) as well as before and after stent implantation (percutaneous coronary intervention phase). Simultaneous evaluation of C-reactive protein (C-reactive protein immonoturbidimetry) and plasma cytokine levels (interleukins-1, -6, -10 and tumor necrosis alpha by immunoassay) was also performed. To track the earliest detectable change in the first few minutes after stent deployment, all measurements were performed before and 60 min after the procedures.

RESULTS

CD11b expression increased 1 h after stent deployment in neutrophils (P<0.0001) and monocytes (P<0.0001). A comparable increase, however, was also observed after coronary angiography (neutrophils, P=0.03; monocytes, P=0.01), although the increase of CD11b expression was greater after percutaneous coronary intervention on both neutrophils (90 vs. 40%, P=0.014) and monocytes (65 vs. 33%, P=0.04). CD62L expression decreased significantly after percutaneous coronary intervention (neutrophils, P=0.01; monocytes, P=0.006), but remained unchanged after coronary angiography. Plasma cytokine and C-reactive protein concentrations did not change after the procedures.

CONCLUSION

CD62L appears to be a specific and reliable early cellular biomarker of leukocyte activation after percutaneous coronary intervention, when this procedure is performed in patients with previous ST elevation myocardial infarction. Whether this marker represents also a potential predictor of future events and/or restenosis in this group of patients remains to be defined.

Clinical outcomes of dexamethasone-eluting stent implantation in ST-elevation acute myocardial infarction

OBJECTIVES

The aim of our study was to evaluate the safety and midterm clinical results of dexamethasone-eluting stent (DexES) implantation in ST-segment elevation acute myocardial infarction (STEMI).

BACKGROUND

Inflammation plays a pivotal role in both inestabilization of coronary atherosclerotic plaques and development of restenosis after stent placement. Antiinflammatory agents may attenuate those mechanisms and improve clinical outcomes. There is little information about clinical results of DexES and no data are available about their utilization during percutaneous coronary intervention (PCI) in STEMI.

METHODS

Consecutive patients with STEMI that underwent primary or rescue PCI in our institution were treated with DexES. Clinical follow-up with routine realization of noninvasive test for detection of myocardial ischemia and coronariography if necessary, were performed. The objective of the study was to evaluate the rate of MACE (death, reinfarction, or target lesion revascularization) during midterm follow-up.

RESULTS

The procedure was successful in 96.7% of cases. There were no in-hospital deaths or reinfarctions. One acute stent thrombosis occurred and no subacute thrombosis were observed. During a mean follow-up period of 384 days, cardiac-related death was 1.1%, there were no reinfarctions or late stent thrombosis and target lesion revascularization rate was 4.2%.

CONCLUSION

We conclude that utilization of DexES for PCI in STEMI is safe and provides good midterm clinical outcomes.

Coronary restenotic reduction of drug-eluting stenting may be due to its anti-inflammatory effects

The development of coronary stent has revolutionized the field of interventional cardiology by reducing the incidence of restenosis after balloon angioplasty. However, the stent has still associated with a serious complication, namely, in-stent restenosis. Although, restenosis following coronary stenting has long been attributed to neointimal proliferation, thrombosis, and negative remodeling, the inflammation may be a trigger for those vascular reactions following coronary stenting. Both experimental and clinical studies have demonstrated a marked activation of local and systemic inflammatory response following stent implantation, suggesting that inflammation may play an important role in determining in-stent restenosis via neointimal proliferation. The key role of inflammation in vascular healing and in-stent retsenosis has also been increasingly well understood. Recently, drug-eluting stents (DESs) have been shown to decrease in-stent restenosis in a large number of clinical studies. In addition to their anti-proliferative activity, DESs have been considered to possess an anti-inflammatory property, especially for sirolimus-eluting stent compared with bare metal stent. Moreover, the benefit of the anti-inflammatory therapy during the peri-procedural period and long-term follow-up by means of drug administration is also dependent on the inflammatory status during percutaneous coronary intervention. Measurement of cytokine and acute phase proteins, such as C-reactive protein, therefore, may be important to identify high-risk subjects and develop specific treatment tailored to the individual patients with stent restenosis. Thus, therapeutic approach should be further directed toward increasing local resistance to proliferative inflammatory stimuli by means of anti-proliferative, locally delivered drugs and reducing the magnitude and persistence of systemic inflammation.