Pharmacological inhibition of coronary restenosis: systemic and local approaches

Revolutionizing Cardiovascular Frontiers: A Dive Into Cutting-Edge Innovations in Coronary Stent Technology

Plain balloon angioplasty was the initial method used to enlarge the intracoronary lumen size. However, it was linked to acute coronary closure due to early vessel recoil. This led to the invention of coronary stents, which offer mechanical support to open and maintain the vascular lumen. Nevertheless, the metallic scaffold introduced other issues, such as thrombosis and restenosis caused by neointimal proliferation. To address these concerns, polymers were employed to cover the scaffold, acting as drug reservoirs and regulators for controlled drug release. The use of polymers prevents direct contact between blood and metallic scaffolds. Drugs within the stent were incorporated to inhibit proliferation and expedite endothelialization in the healing process. Despite these advancements, adverse effects still arise due to the inflammatory reaction caused by the polymer material. Consequently, resorbable polymers and scaffolds were later discovered, but they have limitations and are not universally applicable. Various scaffold designs, thicknesses, materials, polymer components, and drugs have their own advantages and complications. Each stent generation has been designed to address the shortcomings of the preceding generation, yet new challenges continue to emerge. Conflicting data regarding the long-term safety and efficacy of coronary stents, especially in the extended follow-up, further complicates the assessment.

Evolutionary perspective of drug eluting stents: from thick polymer to polymer free approach

BACKGROUND

Introduction of Bare Metal Stents (BMS) was itself a revolutionary step in the history of the medical industry; however, Drug Eluting Stents (DES) maintained its superiority over BMS in every aspect from restenosis rate to late lumen loss. The reason behind the magnanimous position of the DES in the stent market is the degree of improvement with which it evolves. New and better stents come into the market every year, surpassing their predecessors by many folds.

LITERATURE REVIEW

This review paper discusses the journey of DES with supporting clinical trials in detail. In the first generation, there were stainless-steel stents with thicker coatings. Although they had superior results compared to BMS, there was still room for improvement. Afterward came the second-generation stents, which had superior metal platforms with thinner struts and thin coatings. The drugs were also changed from Paclitaxel and Sirolimus to Zotrolimus and Everolimus. These stents performed best; however, there was an issue of permanent coating, which remained intact over the stent surface after complete drug elution and started to cause issues in longer-term studies. Hence, an improved version of DES was introduced to these permanent coatings called the third generation of drug eluting stents, which initially utilized biodegradable polymer and ultimately moved towards polymer free drug coatings. This generation has introduced a unique amalgam of technologies to achieve its polymer free coatings; however, researchers have numerous prospects of growth in this field. This review paper highlights the major coups of stent technology evolution from BMS to DES, from thick polymeric coatings to thin coatings and from durable polymers to polymer free DES.

CONCLUSION

In conclusion, though the medical industry promptly accepted BMS as the best treatment option for cardiovascular diseases; however, DES has provided even better results than BMS. In DES, the first and second generation has ruled the technology for many years and are still on the shelves. Still, the issues aroused due to durable polymer shifted the attention towards biodegradable drug eluting stents, the third generation growing rapidly. But the scientific community has not restricted themselves and is investigating bioresorbable stents that completely eliminate the polymer intervention in drug eluting stent technology.

Long Non-Coding RNAs Might Regulate Phenotypic Switch of Vascular Smooth Muscle Cells Acting as ceRNA: Implications for In-Stent Restenosis

Coronary in-stent restenosis is a late complication of angioplasty. It is a multifactorial process that involves vascular smooth muscle cells (VSMCs), endothelial cells, and inflammatory and genetic factors. In this study, the transcriptomic landscape of VSMCs’ phenotypic switch process was assessed under stimuli resembling stent injury. Co-cultured contractile VSMCs and endothelial cells were exposed to a bare metal stent and platelet-derived growth factor (PDGF-BB) 20 ng/mL. Migratory capacity (wound healing assay), proliferative capacity, and cell cycle analysis of the VSMCs were performed. RNAseq analysis of contractile vs. proliferative VSMCs was performed. Gene differential expression (DE), identification of new long non-coding RNA candidates (lncRNAs), gene ontology (GO), and pathway enrichment (KEGG) were analyzed. A competing endogenous RNA network was constructed, and significant lncRNA–miRNA–mRNA axes were selected. VSMCs exposed to “stent injury” conditions showed morphologic changes, with proliferative and migratory capacities progressing from G0-G1 cell cycle phase to S and G2-M. RNAseq analysis showed DE of 1099, 509 and 64 differentially expressed mRNAs, lncRNAs, and miRNAs, respectively. GO analysis of DE genes showed significant enrichment in collagen and extracellular matrix organization, regulation of smooth muscle cell proliferation, and collagen biosynthetic process. The main upregulated nodes in the lncRNA-mediated ceRNA network were PVT1 and HIF1-AS2, with downregulation of ACTA2-AS1 and MIR663AHG. The PVT1 ceRNA axis appears to be an attractive target for in-stent restenosis diagnosis and treatment.

Highly Selective PPARα (Peroxisome Proliferator-Activated Receptor α) Agonist Pemafibrate Inhibits Stent Inflammation and Restenosis Assessed by Multimodality Molecular-Microstructural Imaging

BACKGROUND

New pharmacological approaches are needed to prevent stent restenosis. This study tested the hypothesis that pemafibrate, a novel clinical selective PPARα (peroxisome proliferator‐activated receptor α) agonist, suppresses coronary stent‐induced arterial inflammation and neointimal hyperplasia.

METHODS AND RESULTS

Yorkshire pigs randomly received either oral pemafibrate (30 mg/day; n=6) or control vehicle (n=7) for 7 days, followed by coronary arterial implantation of 3.5 × 12 mm bare metal stents (2–4 per animal; 44 stents total). On day 7, intracoronary molecular‐structural near‐infrared fluorescence and optical coherence tomography imaging was performed to assess the arterial inflammatory response, demonstrating that pemafibrate reduced stent‐induced inflammatory protease activity (near‐infrared fluorescence target‐to‐background ratio: pemafibrate, median [25th‐75th percentile]: 2.8 [2.5–3.3] versus control, 4.1 [3.3–4.3], P=0.02). At day 28, animals underwent repeat near‐infrared fluorescence–optical coherence tomography imaging and were euthanized, and coronary stent tissue molecular and histological analyses. Day 28 optical coherence tomography imaging showed that pemafibrate significantly reduced stent neointima volume (pemafibrate, 43.1 [33.7–54.1] mm³ versus control, 54.2 [41.2–81.1] mm³; P=0.03). In addition, pemafibrate suppressed day 28 stent‐induced cellular inflammation and neointima expression of the inflammatory mediators TNF‐α (tumor necrosis factor‐α) and MMP‐9 (matrix metalloproteinase 9) and enhanced the smooth muscle differentiation markers calponin and smoothelin. In vitro assays indicated that the STAT3 (signal transducer and activator of transcription 3)–myocardin axes mediated the inhibitory effects of pemafibrate on smooth muscle cell proliferation.

CONCLUSIONS

Pemafibrate reduces preclinical coronary stent inflammation and neointimal hyperplasia following bare metal stent deployment. These results motivate further trials evaluating pemafibrate as a new strategy to prevent clinical stent restenosis.

Patient and Institutional Costs of Failure of Angioplasty of the Superficial Femoral Artery

BACKGROUND

Debate surrounds the optimal management of superficial femoral artery (SFA) disease. Randomized trial data rarely reflect real world findings, specifically the consequences to the patient of angioplasty failure. We observed the effect of a failed SFA angioplasty on the need for repeated clinic visits, hospital readmissions, imaging requirements, and reinterventions.

METHODS

We reviewed a consecutive series of 148 patients (94 men, median age 72 years) undergoing solely SFA angioplasty over a 2-year period. Patient preangioplasty demographics and 2-year post-PTA follow-up data were collated, including hospital attendances (inpatient/outpatient), further imaging (including radiation exposure) and revascularization attempts. We defined "failed angioplasty" as presence of clinical symptoms with radiological evidence of significant restenosis after an initial successful primary SFA angioplasty.

RESULTS

Fifty-four patients represented with a failed angioplasty (median time of 4 months after index PTA). In this group, failure of index angioplasty resulted in a further 185 restenosis-related clinic visits and a total of 537 bed days of inpatient stay. This group underwent a further 149 imaging events and required a further 34 endovascular revascularization procedures and 12 infrainguinal bypass procedures. These interventions and investigations corresponded to overall effective radiation dose across all patients of 190.69 mSv. Of the cohort of 99 patients who did not have a "failed angioplasty," they required 100 clinic visits, 21 further scans (total radiation dose 6.42 mSv), and 36 bed days of inpatient admission.

CONCLUSIONS

Failed angioplasty results in significant additional consequences for patients and health-care systems. Further work should focus on refining decision-making, providing the right procedure to the right patient at the right time.

Vascular Wall Reactions to Coronary Stents-Clinical Implications for Stent Failure

Coronary stents belong to the most commonly implanted devices worldwide. A number of different types of stent exist, with very different mechanical and biochemical characteristics that influence their interactions with vascular tissues. Inappropriate inflammatory reactions are the major cause of the two major complications that follow implantation of stents in a percentage as high as 5-20%. It is therefore important to understand these reactions and how different they are among different generations of stents.

Cilostazol-based triple versus potent P2Y12 inhibitor-based dual antiplatelet therapy in patients with acute myocardial infarction undergoing percutaneous coronary intervention

Although potent P2Y12 inhibitor-based dual antiplatelet therapy (DAPT) has replaced clopidogrel-based therapy as the standard treatment in patients with acute myocardial infarction (AMI), there is a concern about the risk of bleeding in East Asian patients. We compared the efficacy and safety of cilostazol-based triple antiplatelet therapy (TAT) with potent P2Y12 inhibitor-based DAPT in Korean patients. A total of 4152 AMI patients who underwent percutaneous coronary intervention (PCI) in the Korea Acute Myocardial Infarction Registry were analyzed retrospectively. Patients were divided into two groups: the TAT group (aspirin + clopidogrel + cilostazol, n = 3161) and the potent DAPT group (aspirin + potent P2Y12 inhibitors [ticagrelor or prasugrel], n = 991). Major clinical outcomes at 30 days and 2 years were compared between the two groups using propensity score matching (PSM) analysis. After PSM (869 pairs), there were no significant differences between the two groups in the incidence of total death, cardiac death, myocardial infarction (MI), target vessel revascularization, stent thrombosis, and stroke at 30 days and 2 years. However, the Thrombolysis in Myocardial Infarction (TIMI) major or minor bleeding rates were significantly lower in the TAT group compared with the potent DAPT group at 2 years (6.4% vs. 3.6%, p = 0.006). In Korean AMI patients undergoing PCI, TAT with cilostazol was associated with lower bleeding than the potent P2Y12 inhibitor-based DAPT without increased ischemic risk. These results could provide a rationale for the use of TAT in East Asian AMI patients.

Association study of matrix metalloproteinase 3 5A/6A polymorphism with in-stent restenosis after percutaneous coronary interventions in a Han Chinese population

Objective

We aimed to investigate the association between the 5A/6A promoter polymorphism in the matrix metalloproteinase 3 (MMP3) gene and in-stent restenosis (ISR) in a regional Chinese population.

Methods

A total of 818 patients who underwent primary implantation of drug-eluting stents were enrolled and received a 6-month follow-up angiography and DNA genotyping of the 5A/6A polymorphism.

Results

ISR was found in 36.9% of all patients (302 ISR vs. 516 no ISR). The genotype proportion of 6A6A was significantly increased in ISRs (74.2% ISR vs. 66.8% no ISR), whereas the allele frequency of 5A was significantly decreased in ISR patients (25.8%) compared with controls who did not undergo ISR (33.1%).

Conclusions

Our data indicate that the MMP3 6A6A genotype is a genetic susceptibility factor for ISR after coronary stent placement, but the 5A allele can lower the risk for patients within 6 months after stenting. Therefore, genotyping 5A/6A in the MMP3 promoter is suggested for patients who undergo coronary stent implantation.

The efficacy and safety of cilostazol as an alternative to aspirin in Chinese patients with aspirin intolerance after coronary stent implantation: a combined clinical study and computational system pharmacology analysis

Dual antiplatelet therapy (DAT) with aspirin and clopidogrel is the standard regimen to achieve rapid platelet inhibition and prevent thrombotic events. Currently, little information is available regarding alternative antiplatelet therapy in patients with an allergy or intolerance to aspirin. Although cilostazol is already a common alternative to aspirin in clinical practice in China, its efficacy and safety remain to be determined. We retrospectively analyzed 613 Chinese patients who had undergone primary percutaneous coronary intervention (PCI). Among them, 405 patients received standard DAT (aspirin plus clopidogrel) and 205 patients were identified with intolerance to aspirin and received alternative DAT (cilostazol plus clopidogrel). There were no significant differences between the two groups in their baseline clinical characteristics. The main outcomes of the study included major adverse cardiac events (MACEs) and bleeding events during 12 months of follow-up. The MACEs endpoint was reached in 10 of 205 patients treated with cilostazol (4.9%) and in 34 of 408 patients treated with aspirin (8.3%). No statistically significant difference was observed in MACEs between the two groups. However, patients in the cilostazol group had less restenosis than did patients in the aspirin group (1.5% vs 4.9%, P=0.035). The occurrence of bleeding events tended to be lower in the cilostazol group (0.49% vs 2.7%, P=0.063). These clinical observations were further analyzed using network system pharmacology analysis, and the outcomes were consistent with clinical observations and preclinical data reports. We conclude that in Chinese patients with aspirin intolerance undergoing coronary stent implantation, the combination of clopidogrel with cilostazol may be an efficacious and safe alternative to the standard DAT regimen.

Intermedin reduces neointima formation by regulating vascular smooth muscle cell phenotype via cAMP/PKA pathway

BACKGROUND AND AIMS

Vascular smooth muscle cell (VSMC) dedifferentiation contributes to neointima formation, which results in various vascular disorders. Intermedin (IMD), a cardiovascular paracrine/autocrine polypeptide, is involved in maintaining circulatory homeostasis. However, whether IMD protects against neointima formation remains largely unknown. The purpose of this study is to investigate the role of IMD in neointima formation and the possible mechanism.

METHODS

IMD_1-53 (100ng/kg/h) or saline water was used on rat carotid-artery balloon-injury model. The mouse left common carotid-artery ligation-injury model was established using IMD-transgenic and C57BL/6J mice. Immunohistochemistry and immunofluorescence staining was used to detect the protein expression in rat carotid arteries. Radioimmunoassay was used to determine the serum IMD level. The hematoxylin andeosin staining was used for carotid arteries morphological testing. In vitro, for rat primary cultured VSMC phenotype transition, proliferation and migration assays, platelet-derived growth factor-BB (PDGF-BB) reagent and IMD_1-53 peptide were added to the culture media at the final concentration of 20 ng/mL and 10^-7mol/L respectively. Quantification of VSMC proliferation involved MTT and BrdU assay and migration was detected by wound-healing assay. Western blot and realtime PCR were used to detect the protein and mRNA levels of tissues or cells.

RESULTS

With the rat carotid-artery balloon-injury model, IMD was significantly downregulated in injured arteries and plasma. Exogenous IMD_1-53 greatly inhibited neointima formation and prevented VSMC from switching to a synthetic phenotype. With the left common carotid-artery ligation-injury model, IMD-transgenic mice showed less neointima formation than C57BL/6J mice. PDGF-BB reduced IMD mRNA expression in rat primary cultured VSMCs but increased that of its receptors, calcitonin receptor-like receptor or receptor activity-modifying proteins. Furthermore, PDGF-BB promoted VSMC proliferation and migration and transformed VSMCs to the synthetic phenotype, which was reversed with IMD_1-53 treatment. Mechanistically, IMD_1-53 maintained the contractile VSMC phenotype via the cyclic adenosine monophosphate/protein kinase A (cAMP/PKA) pathway.

CONCLUSIONS

IMD attenuated neointima formation both in the rat model of carotid-artery balloon injury and mouse model of common carotid-artery ligation injury. IMD protection may be mediated by maintaining a VSMC contractile phenotype via the cAMP/PKA pathway.

Restenosis after Coronary and Peripheral Intervention: Efficacy and Clinical Impact of Cilostazol

Restenosis is one of the main complications in patients undergoing coronary or peripheral revascularization procedures and is the leading cause for their long-term failures. Cilostazol is the only pharmacotherapy that showed an adequate efficacy for preventing restenosis in randomized, controlled studies after coronary or peripheral revascularization procedures. The present review sums up the main clinical evidence supporting the use of cilostazol after revascularization interventions, focusing on all its benefits, warnings, and administration schedules.

Association of increased serum CTRP5 levels with in-stent restenosis after coronary drug-eluting stent implantation: CTRP5 promoting inflammation, migration and proliferation in vascular smooth muscle cells

BACKGROUND

We investigated whether serum level of C1q/TNF-related protein (CTRP) 5 is associated with in-stent restenosis (ISR) after percutaneous coronary intervention (PCI) with drug-eluting stent (DES) implantation, and assessed the biological effects of CTRP5 in human aortic smooth muscle cells (hASMCs).

METHODS AND RESULTS

Serum CTRP5 levels were assayed in 306 patients with and 306 patients without angiographic ISR at approximately one year after DES-based PCI. Multivariate logistic regression analysis was performed to determine risk factors for ISR. Notably, serum CTRP5 levels were higher in ISR patients than in non-ISR counterparts (197±84ng/mL vs. 150±74ng/mL, P<0.001). Compared with the lowest tertile (<125ng/mL) of CTRP5, patients with the mid (125-200ng/mL) and the highest tertile (>200ng/mL) of CTRP5 had a more than 1.6-fold (adjusted OR=1.670-2.127, P≤0.039) and 7.4-fold (adjusted OR=7.478-11.264, all P<0.001) increased risk of ISR (all P for trend <0.001), respectively, after adjustment for potential clinical, biochemical and angiographic characteristics. To assess the biological effects of CTRP5, we stimulated hASMCs with this protein. CTRP5 concentration-dependently induced the expression of MMP-2, cyclin D1 and TNF-α in hASMCs, with activation of Notch1, TGF-β and hedgehog signaling pathways. Consistently, this protein promoted migration and proliferation of hASMCs in wound-healing, Boyden chamber and Brdu incorporation assay.

CONCLUSION

Increased serum CTRP5 level is associated with ISR after PCI with DES implantation. CTRP5 promotes proliferation, inflammation and migration in vascular smooth muscle cells through activation of multiple pathways.

Five-year clinical outcomes in patients with diabetes mellitus treated with polymer-free sirolimus- and probucol-eluting stents versus second-generation zotarolimus-eluting stents: a subgroup analysis of a randomized controlled trial

Background

Improved outcomes in patients with diabetes mellitus undergoing percutaneous coronary intervention remain an unmet clinical need. We assessed the long-term efficacy and safety of novel polymer-free sirolimus- and probucol-eluting stent in diabetic patients enrolled in intracoronary stenting and angiographic results: test efficacy of sirolimus- and probucol-eluting versus zotarolimus-eluting stents 5 trial.

Methods

In a pre-specified subgroup analysis, outcomes of diabetic patients treated with a sirolimus- and probucol-eluting stent or a second-generation zotarolimus-eluting stent were compared. The primary endpoint was a device-oriented composite outcome comprising cardiac death, target vessel-related myocardial infarction (MI), or target lesion revascularization (TLR) at 5-year follow-up. Event-free survival was assessed using the Kaplan–Meier method. Hazard ratios (HR) and 95 % confidence intervals (CI) were estimated from univariate Cox proportional hazards models.

Results

A total of 870 patients with diabetes mellitus were treated with either a sirolimus- and probucol-eluting stent (n = 575) or a second-generation zotarolimus-eluting stent (n = 295). At 5 years, the rate of device-oriented composite endpoint was comparable between the sirolimus- and probucol-eluting stent and the second-generation zotarolimus-eluting stent (32.9 versus 33.4 %, HR 0.88, 95 % CI 0.76–1.26). No significant differences were observed between the sirolimus- and probucol-eluting stent and the second-generation zotarolimus-eluting stent groups in the incidence of cardiac death (15.6 versus 16.7 % HR 0.92, 95 % CI 0.63–1.32), target-vessel MI (4.6 versus 6.6 %, HR 0.73, 95 % CI 0.40–1.34), and TLR (18.6 versus 18.8 %, HR 1.00, 95 % CI, 0.72–1.41). The rate of definite or probable stent thrombosis was low and similar in both groups (2.5 versus 2.6 %, HR 1.02, 95 % CI, 0.41–2.52).

Conclusions

In patients with diabetes the long-term efficacy and safety of a polymer-free sirolimus- and probucol-eluting stent were comparable to a second-generation durable polymer zotarolimus-eluting stent.

Trial registration ClinicalTrials.gov NCT00598533. Registered 10 January 2008

Pimecrolimus increases the expression of interferon-inducible genes that modulate human coronary artery cells proliferation

The pharmacodynamics of the loaded compounds defines clinical failure or success of a drug-eluting device. Various limus derivatives have entered clinics due to the observed positive outcome after stent implantation, which is explained by their antiproliferative activity resulting from inhibition of the cytosolic immunophilin FK506-binding protein 12. Although pimecrolimus also binds to this protein, pimecrolimus-eluting stents failed in clinics. However, despite its impact on T lymphocytes little is known about the pharmacodynamics of pimecrolimus in cultured human coronary artery cells. We were able to show that pimecrolimus exerts antiproliferative activity in human smooth muscle and endothelial cells. Furthermore in those cells pimecrolimus induced transcription of interferon-inducible genes which in part are known to modulate cell proliferation. Modulation of gene expression may be part of an interaction between calcineurin, the downstream target of the pimecrolimus/FK506-binding protein 12-complex, and the toll-like receptor 4. In accordance are our findings showing that silencing of toll-like receptor 4 by siRNA in A549 a lung carcinoma cell line reduced the activation of interferon-inducible genes upon pimecrolimus treatment in those cells. Based on our findings we hypothesize that calcineurin inhibition may induce the toll-like receptor 4 mediated activation of type I interferon signaling finally inducing the observed effect in endothelial and smooth muscle cells. The crosstalk of interferon and toll-like receptor signaling may be a molecular mechanism that contributed to the failure of pimecrolimus-eluting stents in humans.

Safety and efficacy of a novel iopromide-based paclitaxel-eluting balloon following bare metal stent implantation in rabbit aorta abdominalis

BACKGROUND

Drug-eluting balloons (DEB) may be promising technology for treating atherosclerotic arterial disease. In fact, several DEBs have been clinically available for the treatment of coronary in-stent restenosis (ISR), de novo coronary lesions, and peripheral artery disease.

OBJECTIVE

We sought to elucidate the mechanism of action and in vivo safety and efficacy of a novel iopromide-based paclitaxel-eluting balloon.

METHODS

In vitro cytotoxicity of a novel DEB on human umbilical vein endothelial cells (HUVECs) and in vivo pharmacokinetics of DEB in a rabbit aorta abdominalis were assessed. Then, bare metal stents (BMS) were implanted at both the proximal and distal sites of the rabbit aorta abdominalis. Stented vascular segments were immediately dilated with a bare balloon (control group) or the DEB (DEB group) randomly. Histological evaluation was performed in all treated segments at 28 days. Because paclitaxel is a tubulin-disrupting agent that binds preferentially to β-tubulin, we measured β-tubulin expression in aortal stent specimens via immunohistochemistry.

RESULTS

We observed that DEB was compatible and could reduce neointimal hyperplasia compared with the bare balloon. Meanwhile, immunohistochemistry revealed that β-tubulin expression in the DEB group increased compared with the control group, indirectly suggesting successful uptake of paclitaxel by vessel walls after DEB dilation.

CONCLUSIONS

The novel DEB is safe and has a favorable vascular healing response on neointimal hyperplasia.

Antiproliferative Drugs for Restenosis Prevention

Cardiovascular disease is a leading cause of death and disability worldwide. Current treatment strategies aimed at treating the symptoms and consequences of obstructive vascular disease have embraced both optimal medical therapy and catheter-based percutaneous coronary intervention with drug-eluting stents. Drug-eluting stents elute antiproliferative drugs inhibiting vascular smooth muscle cell proliferation, which occurs in response to injury and thus prevents restenosis. However, all drugs currently approved for use in drug-eluting stents do not discriminate between proliferating vascular smooth muscle cells and endothelial cells, thus delaying re-endothelialization and subsequent vascular healing.

Effect of Pioglitazone in Preventing In-Stent Restenosis after Percutaneous Coronary Intervention in Patients with Type 2 Diabetes: A Meta-Analysis

BACKGROUND

The benefits of pioglitazone in patients with type 2 diabetes mellitus (T2DM) after percutaneous coronary intervention (PCI) is unclear.

OBJECTIVES

To evaluate the effect of pioglitazone on prevention of in-stent restenosis (ISR) in patients with T2DM after PCI.

METHODS

All full-text published relevant studies compared the effect of pioglitazone with control group (placebo or no pioglitazone treatment) on ISR in patients with T2DM after PCI were identified by searching the databases including PubMed, EMBASE, Cochrane Library and ISI Web of Science through October 2015. The endpoints were defined as the rate of ISR, late lumen loss, in-stent neointimal volume, target lesion revascularization (TLR) and major adverse cardiac events (MACE).

RESULTS

Six studies (5 RCTs and 1 retrospective study), comprising 503 patients, were included into this meta-analysis. In the pioglitazone group, as compared with the control group, the risk ratio for ISR was 0.48 (I2 = 14.5%, P = 0.322; 95%CI 0.35 to 0.68, P<0.001), the risk ratio for TLR was 0.58 (I2 = 6.0%, P = 0.363; 95%CI 0.38 to 0.87, P = 0.009). The result showed there was no association between the use of pioglitazone and the events of MACE (I2 = 36.7%, P = 0.209; RR 0.56, 95%CI 0.30 to 1.05, P = 0.071). For the considerable heterogeneity, further analysis was not suitable for the endpoints of late lumen loss (I2 = 81.9%, P<0.001) and neointimal volume (I2 = 75.9%, P = 0.016).

CONCLUSIONS

The treatment of pioglitazone was associated with a reduction in ISR and TLR in T2DM patients suffering from PCI, except the incidence of MACE.

Thrombin-Induced Platelet-Fibrin Clot Strength Identified by Thrombelastography: A Novel Prothrombotic Marker of Coronary Artery Stent Restenosis

BACKGROUND AND OBJECTIVE

In-stent restenosis (ISR) is a limitation of percutaneous coronary intervention and has been linked to specific clinical and angiographic variables. We aimed to simultaneously assess thrombosis biomarkers and lipid levels in patients with and without ISR.

METHODS

Consecutive patients (n = 170) with a history of coronary stenting undergoing elective angiography were studied. Blood samples for thrombelastography, light transmittance aggregometry, and lipid levels were obtained prior to cardiac catheterization.

RESULTS

Sixty-nine patients (41%) had ISR (>50% luminal diameter stenosis). Among patients with ISR, 40 (58%) had ISR in more than one stent bed. Patients with ISR were more often female (37.7% vs. 21.8%, P = 0.04), had higher thrombin-induced platelet-fibrin clot strength (TIP-FCS) (69.9 mm vs. 65.6 mm, P < 0.001), and a higher ApoB/A1 ratio (0.65 vs. 0.59, P = 0.03). In patients on dual antiplatelet therapy (n = 86), there were no differences in ADP-, arachidonic acid-, and collagen-induced platelet aggregation between groups. The frequency of patients with ISR increased with TIP-FCS quartiles and by ROC analysis, TIP-FCS = 67.0 mm was the cutpoint for identification of ISR (AUC = 0.80 (95%CI 0.73-0.87, P < 0.0001). By multivariate analysis, TIP-FCS ≥67.0 mm strongly associated with ISR (OR = 7.3, P = 0.004).

CONCLUSION

Patients with ISR identified at the time of cardiac catheterization have a prothrombotic phenotype indicated by high TIP-FCS, a novel marker. Studies to confirm the prognostic utility of high TIP-FCS for the development of ISR are ongoing.

Stent thrombosis and restenosis: what have we learned and where are we going? The Andreas Grüntzig Lecture ESC 2014

Modern-day stenting procedures leverage advances in pharmacotherapy and device innovation. Patients treated with contemporary antiplatelet agents, peri-procedural antithrombin therapy and new-generation drug-eluting stents (DES) have excellent outcomes over the short to medium term. Indeed, coupled with the reducing costs of these devices in most countries there remain very few indications where patients should be denied treatment with standard-of-care DES therapy. The two major causes of stent failure are stent thrombosis (ST) and in-stent restenosis (ISR). The incidence of both has reduced considerably in recent years. Current clinical registries and randomized trials with broad inclusion criteria show rates of ST at or <1% after 1 year and ∼0.2-0.4% per year thereafter; rates of clinical ISR are 5% respectively. Angiographic surveillance studies in large cohorts show rates of angiographic ISR of ∼10% with new-generation DES. The advent of high-resolution intracoronary imaging has shown that in many cases of late stent failure neoatherosclerotic change within the stented segment represents a final common pathway for both thrombotic and restenotic events. In future, a better understanding of the pathogenesis of this process may translate into improved late outcomes. Moreover, the predominance of non-stent-related disease as a cause of subsequent myocardial infarction during follow-up highlights the importance of lifestyle and pharmacological interventions targeted at modification of the underlying disease process. Finally, although recent developments focus on strategies which circumvent the need for chronically indwelling stents--such as drug-coated balloons or fully bioresorbable stents-more data are needed before the wider use of these therapies can be advocated.