Efficacy of drug-eluting stents for treating in-stent restenosis of drug-eluting stents (from the Korean DES ISR multicenter registry study [KISS])

Risk prediction of in-stent restenosis among patients with coronary drug-eluting stents: current clinical approaches and challenges

Introduction: In-stent restenosis (ISR) has been one of the biggest limitations to the success of percutaneous coronary intervention for the treatment of coronary artery disease (CAD). The introduction of drug-eluting stent (DES) was a revolution in the treatment of CAD because these devices drastically reduced ISR to very low levels (<5%). Subsequently, newer generation DES treatments have overcome the drawbacks of first-generation DES, i.e. delayed endothelialization, and late stent thrombosis. However, the issue of late ISR, including neoatherosclerosis after DES implantation especially in high-risk patients and complex lesions, still exists as a challenge to be overcome.Areas covered: We discuss the mechanisms of ISR development including neoatherosclerosis, past and current clinical status of ISR, and methods to predict and overcome this issue from pathological and clinical points of view.Expert opinion: The initial drawbacks of first-generation DES, such as delayed endothelial healing and subsequent risk of late stent thrombosis, have been improved upon by the current generation DES. To achieve better long-term clinical outcomes, further titration of drug-release and polymer degradation profile, strut thickness as well as material innovation are needed.

MiR-378a-5p Regulates Proliferation and Migration in Vascular Smooth Muscle Cell by Targeting CDK1

Objective: Abnormal proliferation or migration of vascular smooth muscle cells (VSMCs) can lead to vessel lesions, resulting in atherosclerosis and in stent-restenosis (IRS). The purpose of our study was to establish the role of miR-378a-5p and its targets in regulating VSMCs function and IRS.

Methods: EdU assays and Cell Counting Kit-8 (CCK-8) assays were applied to evaluate VSMCs proliferation, wound healing assays and transwell assays were applied to assess cells migration. Furthermore, quantitative reverse transcription–polymerase chain reaction (qRT-PCR) was performed to investigate the expression level of miR-378a-5p IRS patients and healthy individuals. Target genes were predicted using Target Scan and miRanda software, and biological functions of candidate genes were explored through bioinformatics analysis. Moreover, RNA-binding protein immunoprecipitation (RIP) was carried out to analyze the miRNAs interactions with proteins. We also used Immunofluorescence (IF) and fluorescence microscopy to determine the binding properties, localization and expression of miR-378a-5p with downstream target CDK1.

Results: The expression of miR-378a-5p was increased in the group with stent restenosis compared with healthy people, as well as in the group which VSMCs stimulated by platelet-derived growth factor-BB (PDGF-BB) compared with NCs. MiR-378a-5p over-expression had significantly promoted proliferative and migratory effects, while miR-378a-5p inhibitor suppressed VSMC proliferation and migration. CDK1 was proved to be the functional target of miR-378a-5p in VSMCs. Encouragingly, the expression of miR-378a-5p was increased in patients with stent restenosis compared with healthy people, as well as in PDGF-BB-stimulated VSMCs compared with control cells. Furthermore, co-transfection experiments demonstrated that miR-378a-5p over-expression promoted proliferation and migration of VSMCs specifically by reducing CDK1 gene expression levels.

Conclusion: In this investigatory, we concluded that miR-378a-5p is a critical mediator in regulating VSMC proliferation and migration by targeting CDK1/p21 signaling pathway. Thereby, interventions aimed at miR-378a-5p may be of therapeutic application in the prevention and treatment of stent restenosis.

Propensity Score-Based Methods in Comparative Effectiveness Research on Coronary Artery Disease

This review examines the conduct and reporting of observational studies using propensity score-based methods to compare coronary artery bypass grafting (CABG), percutaneous coronary intervention (PCI), or medical therapy for patients with coronary artery disease. A systematic selection process identified 48 studies: 20 addressing CABG versus PCI; 21 addressing bare-metal stents versus drug-eluting stents; 5 addressing CABG versus medical therapy; 1 addressing PCI versus medical therapy; and 1 addressing drug-eluting stents versus balloon angioplasty. Of 32 studies reporting information on variable selection, 7 relied exclusively on statistical criteria for the association of covariates with treatment, and 5 used such criteria to determine whether product or nonlinear terms should be included in the propensity score model. Twenty-five (52%) studies reported assessing covariate balance using the estimated propensity score, but only 1 described modifications to the propensity score model based on this assessment. The over 400 variables used in the 48 propensity score models were classified into 12 categories and 60 subcategories; only 17 subcategories were represented in at least half of the propensity score models. Overall, reporting of propensity score-based methods in observational studies comparing CABG, PCI, and medical therapy was incomplete; when adequately described, the methods used were often inconsistent with current methodological standards.

Management of drug eluting stent in-stent restenosis: A systematic review and meta-analysis

BACKGROUND

The optimal management for coronary drug eluting stent in-stent restenosis (DES ISR) is unclear. We performed a meta-analysis of observational and randomized studies to compare the outcomes of management of DES ISR using DES, drug eluting balloon (DEB), or balloon angioplasty (BA).

METHODS

Eligible studies (25 single arm and 13 comparative, including 4 randomized studies with a total of 7,474 patients with DES ISR) were identified using MEDLINE search and proceedings of international meetings. Outcomes studied include major adverse cardiac events (MACE), target lesion revascularization (TLR), target vessel revascularization (TVR), myocardial infarction (MI), stent thrombosis (ST), and mortality. Follow-up ranged from 0.5 to 3.5 years (mean 1.4 years).

RESULTS

The rate of TLR was significantly lower in the DES (odds ratio [OR] 0.50, 95% confidence interval [CI] 0.36-0.69) and DEB (OR 0.31, 95% CI 0.18-0.55) groups compared to BA. Similarly, TVR rate was significantly lower in the DES (OR 0.55, 95% CI 0.39-0.77) and DEB (OR 0.32, 95% CI 0.18-0.58) groups compared to BA. All other outcomes were similar between the DES/BA and DEB/BA comparisons. TLR was significantly lower in the DES group compared to BA for vessels < or > 2.75 mm.

CONCLUSION

Treatment of coronary DES ISR with DES or DEB is associated with a reduction in the risk of TLR and TVR compared to BA alone. The relative risk reduction for TLR with DES is similar to DEB. DEBs have a potential role in the treatment of DES ISR by avoiding placement of another layer of stent. © 2015 Wiley Periodicals, Inc.

Different responses of cell cycle between rat vascular smooth muscle cells and vascular endothelial cells to paclitaxel

Although previous reports showed drug-eluting stent (DES) could effectively inhibit neointima formation, in-stent restenosis (ISR) remains an important obstacle. The purpose of this study was to investigate different effects of paclitaxel on proliferation and cell cycle regulators between vascular smooth muscle cells (VSMCs) and vascular endothelial cells (VECs) of rats in vitro. The cultured VSMCs and VECs of rats from the same tissues were examined by using immunohistochemistry, flow cytometry and Western blotting in control and paclitaxel-treated groups. The results showed paclitaxel could effectively inhibit proliferation of VSMCs and VECs. However, as compared with VECs, proliferation of VSMCs in paclitaxel-treated group decreased less rapidly. The percentage of cells in G0-G1 and G2-M phases was reduced, and that in S phase increased after treatment for 72 h. The expression of cyclin D1 and B1, p27 and PCNA in VSMCs of paclitaxel-treated group was up-regulated, but that of p21 down-regulated as compared with VECs. It is concluded that there are significant differences in the expression of cell cycle regulators and proliferation rate between paclitaxel-treated VSMCs and paclitaxel-treated VECs, suggesting that the G1-S checkpoint regulated by paclitaxel may play a critical role in the development of complications of DES, which provides new strategies for treatments of ISR.

In-stent restenosis of drug-eluting stents

Drug-eluting stents (DES) have emerged as an improved alternative to bare-metal stents by demonstrating reduced rates of restenosis and target lesion revascularization. This emergence has led to the unrestricted use of DES for various indications and lesions, and subsequently revealed DES in-stent restenosis as a novel interventional therapeutic dilemma. Recent insights regarding the patho-physiological processes and therapeutic alternatives have added to the accumulated knowledge regarding the appropriate approach to this phenomenon. This review aims to detail the mechanism and clinical presentation of, and therapeutic strategies for, the treatment of DES in in-stent restenosis.

Meta-analysis of same versus different stent for drug-eluting stent restenosis

Drug-eluting stent (DES) in-stent restenosis (ISR) can be treated by restenting using the same DES as previously placed (same stent strategy), versus switching to a stent that elutes a different drug (different stent strategy). To compare the efficacy of these strategies, a meta-analysis of controlled trials and observational studies evaluating patients with DES ISR was performed. The primary outcome was target lesion revascularization or target vessel revascularization, and secondary outcomes were major adverse cardiovascular events, death, and myocardial infarction. Pooled odds ratios (ORs) were calculated with the generic inverse variance method using a random-effects model. The chi-square test was used to evaluate heterogeneity. Ten studies (1,680 patients) were included. There was no significant heterogeneity among the studies for any end point. The different stent strategy was found to reduce the odds of target lesion revascularization or target vessel revascularization (OR 0.73, 95% confidence interval [CI] 0.55 to 0.96) and major adverse cardiovascular events (OR 0.72, 95% CI 0.54 to 0.96). There was no difference between the 2 strategies in rates of death (OR 1.03, 95% CI 0.49 to 2.16) or myocardial infarction (OR 0.59, 95% CI 0.24 to 1.41). In conclusion, this study demonstrates that treatment of DES ISR by restenting with a different DES than previously placed may lead to improved outcomes compared with the use of the same DES. Further large-scale trials are needed to confirm this effect.