In-Stent Restenosis? The Raiders of the Magic Remedy

Comparison of Drug-Coated Balloons With Drug-Eluting Stents in Patients With In-Stent Restenosis: A Systematic Review and Meta-Analysis

In-stent restenosis (ISR) is the gradual narrowing of the stented coronary segment, presenting as angina or leading to an acute myocardial infarction. Although its incidence has decreased with the use of newer drug-eluting stents (DES), it still carries significant mortality and morbidity risks. We compared the 2 most common interventions for managing DES-related ISR: drug-coated balloons (DCBs) and DES. Electronic databases were searched to identify all randomized controlled trials comparing DCB with DES in patients with DES-ISR. The Mantel-Haenszel method with a random-effects model was used to calculate pooled risk ratios. Five trials comprising 1,100 patients (577 in DCB and 523 in DES group) were included in the final study. The mean follow-up was 42 months. DCB was found to have a higher risk for target lesion revascularization (risk ratio 1.41, p = 0.02) compared with DES. No difference was observed in all-cause mortality, target vessel revascularization, myocardial infarction, or stroke between the 2 intervention arms. In conclusion, management of DES-ISR with DCB has a higher risk of target lesion revascularization compared with re-stenting with DES. The 2 therapeutic interventions are comparable in terms of efficacy and safety profile.

A novel glycyrrhizin acid-coated stent reduces neointimal formation in a rabbit iliac artery model

Introduction: Most drug-eluting stents (DESs) inhibit intimal hyperplasia but impair re-endothelialization. This study aimed to evaluate in vivo strut coverage and neointimal growth in a new glycyrrhizin acid (GA)-eluting stent. Methods: New Zealand White rabbits (n = 20) with atherosclerotic plaques were randomly divided into three groups based on implanted iliac artery stents: bare-metal stents (BMSs), rapamycin-eluting stents, and GA-eluting stents. After the in vivo intravascular ultrasound (IVUS) assessment at 28 days, the vessels were harvested for scanning electron microscopy (SEM) and histology. After 4 weeks of follow-up, the stent and external elastic lamina (EEL) areas were compared among the groups. Results: The rapamycin- or GA-eluting stents significantly reduced the neointimal area compared with BMSs, though GA-eluting stents had the lowest reduction. There were more uncovered struts for rapamycin-eluting stents than those for GA-eluting stents and bare-metal stents. The endothelial nitric oxide synthase (eNOS) expression in GA-eluting stents was much higher than that in BMSs and rapamycin-eluting stents, even though the endothelial coverage between struts was equivalent between BMSs and GA-eluting stents. Moreover, GA-eluting stents markedly promoted re-endothelialization and improved arterial healing compared to rapamycin-eluting stents in a rabbit atherosclerotic model. Conclusion: In conclusion, the novel GA-coated stent used in this study inhibited intimal hyperplasia and promoted re-endothelialization.

Analysis of the incidence and influencing factors associated with binary restenosis of target lesions after drug-coated balloon angioplasty for patients with in-stent restenosis

BACKGROUND

Drug-coated balloon (DCB) is a novel and effective device for coronary artery disease patients with in-stent restenosis (ISR). However, the incidence and possible influencing factors associated with binary restenosis have not yet been adequately assessed.

METHODS

The data are extracted from a prospective, multicenter, randomized controlled trial. A total of 211 patients with ISR were enrolled at 13 centers from August 2017 to October 2018 and treated with DCB. At the 9-month coronary angiographic follow-up, patients were divided into restenosis and non-restenosis groups, and demographic data, lesion features, and laboratory tests were retrospectively reviewed. Furthermore, logistic regression analysis was used to identify possible influencing factors.

RESULTS

All patients successfully underwent treatment, and 166 patients with 190 lesions took part in angiography follow-ups at 9 months. Of these, 41 patients with 44 target lesions developed restenosis following treatment, and the incidence of ISR was 24.7%. There were significant differences in the average length of target lesions and the number of multivessel lesions and fasting plasma glucose (FBG) between the two groups (p < 0.05). Demographic data, cardiac risk factors, left ventricular ejection fractions (LVEF), blood routine tests, biochemical tests, and other features of devices and lesions showed no difference. Logistic regression analyses showed that FBG > 6.1 mmol/L (OR: 7.185 95% CI: 2.939-17.567 P < 0.001) and length of lesion (OR:1.046 95% CI: 1.001-1.093 P = 0.046) were associated risk factors.

CONCLUSIONS

The longer length of lesions, more target lesions and FBG > 6.1 mmol/L per individual may be characteristics of patients showing ISR following treatment. Studies with larger sample size, and more complete follow-up data are needed in the future to expend on these findings.

TRIAL REGISTRATION

No.: NCT04213378, first posted date (30/12/2019).

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.

Platelet-Derived Extracellular Vesicles Increase Col8a1 Secretion and Vascular Stiffness in Intimal Injury

The arterial mechanical microenvironment, including stiffness, is a crucial pathophysiological feature of vascular remodeling, such as neointimal hyperplasia after carotid endarterectomy and balloon dilatation surgeries. In this study, we examined changes in neointimal stiffness in a Sprague-Dawley rat carotid artery intimal injury model and revealed that extracellular matrix (ECM) secretion and vascular stiffness were increased. Once the endothelial layer is damaged in vivo, activated platelets adhere to the intima and may secrete platelet-derived extracellular vesicles (pEVs) and communicate with vascular smooth muscle cells (VSMCs). In vitro, pEVs stimulated VSMCs to promote collagen secretion and cell adhesion. MRNA sequencing analysis of a carotid artery intimal injury model showed that ECM factors, including col8a1, col8a2, col12a1, and elastin, were upregulated. Subsequently, ingenuity pathway analysis (IPA) was used to examine the possible signaling pathways involved in the formation of ECM, of which the Akt pathway played a central role. In vitro, pEVs activated Akt signaling through the PIP₃ pathway and induced the production of Col8a1. MicroRNA (miR) sequencing of pEVs released from activated platelets revealed that 14 of the top 30 miRs in pEVs targeted PTEN, which could promote the activation of the Akt pathway. Further research showed that the most abundant miR targeting PTEN was miR-92a-3p, which promoted Col8a1 expression. Interestingly, knockdown of Col8a1 expression in vivo abrogated the increase in carotid artery stiffness and simultaneously increased the degree of neointimal hyperplasia. Our results revealed that pEVs may deliver miR-92a-3p to VSMCs to induce the production and secretion of Col8a1 via the PTEN/PIP3/Akt pathway, subsequently increasing vascular stiffness. Therefore, pEVs and key molecules may be potential therapeutic targets for treating neointimal hyperplasia.

In-stent restenosis and longitudinal stent deformation: a case report

Background

Longitudinal stent deformation (LSD) is an infrequent complication of percutaneous coronary intervention (PCI), and it may lead to catastrophic clinical outcomes. However, reports of cardiac adverse events associated with LSD are rare.

Case presentation

A 55-year-old man with chest pain was treated for a severe left anterior descending branch (LAD)-diagonal 1 (D1) bifurcation lesion by PCI with two stents in the proximal LAD. LSD occurred during the withdrawal of the trapped D1 wire. High-pressure balloon dilatation was performed in the deformed stent, and the end-angiographic appearance was acceptable, but no additional corrective measures were implemented. Ten months later, the patient represented with acute coronary syndrome. Severe in-stent restenosis (ISR) had suboccluded the proximal LAD, and optical coherence tomography (OCT) visualized multilayered stent struts protruding into the lumen at the compressed segment of the stent. Following complete apposition with balloon dilation, a drug-coated balloon (DCB) was used to avoid an additional permanent metallic layer. He remained angina free, and the angiographic result demonstrated no residual stenosis at the six-month follow-up. To our knowledge, this case demonstrates the first report of ISR triggered by LSD in patients treated with DCBs under the guidance of OCT.

Conclusions

The current report underscores the importance of awareness of LSD, and OCT seems to be the preferred modality to confirm complete apposition. If left without performing additional corrective measures, LSD may be associated with a risk of ISR. Complete apposition with balloon dilation followed by a DCB is a feasible treatment option.

Diagnosis and management challenges of in-stent restenosis in coronary arteries

Over the course of the 3 decades, percutaneous coronary intervention (PCI) with stent implantation transformed the practice of cardiology. PCI with stenting is currently the most widely performed procedure for the treatment of symptomatic coronary disease. In large trials, drug-eluting stents (DES) have led to a significant reduction in in-stent restenosis (ISR) rates, one of the major limitations of bare-metal stents. Due to these favorable findings, DES was rapidly and widely adopted enabling more complex coronary interventions. Nevertheless, ISR remains a serious concern as late stent complications. ISR mainly results from aggressive neointimal proliferation and neoatherosclerosis. DES-ISR treatment continues to be challenging complications for interventional cardiologists.