In-stent restenosis

Drug-coated balloon angioplasty versus drug-eluting stent implantation in ACS patients with different angiographic patterns of in-stent restenosis

BACKGROUND

Drug-coated balloon (DCB) angioplasty and drug-eluting stents (DES) are two widely used treatments for in-stent restenosis (ISR). Focal and non-focal types of ISR affect the clinical outcomes. The present study aims to compare DES reimplantation versus DCB angioplasty in acute coronary syndrome (ACS) patients with focal ISR and non-focal ISR lesions.

METHODS

Patients with ISR lesions underwent percutaneous coronary intervention (PCI) were retrospectively evaluated and divided into DES group and DCB group. The primary endpoint was the incidence of target lesion failure (TLF) at 24 months follow up. Propensity score matching (PSM) was conducted to balance the baseline characteristics.

RESULTS

For focal ISR, TLF was comparable in the DES and DCB groups at 24 months of follow-up (Before PSM, hazard ratio [HR]: 0.70; 95% confidence interval [CI]: 0.39-1.27; p = 0.244; After PSM, HR: 0.83; 95% CI: 0.40-1.73; p = 0.625). For non-focal ISR, TLF was significantly decreased in DES compared with DCB group (Before PSM, HR: 0.43; 95% CI: 0.29-0.63; p < 0.001; After PSM, HR: 0.33; 95% CI: 0.19-0.59; p < 0.001), which was mainly attributed to the lower incidence of clinically indicated target lesion revascularization (CD-TLR) (Before PSM, HR: 0.39; 95% CI: 0.26-0.59; p < 0.001; After PSM, HR: 0.28; 95% CI: 0.15-0.54; p < 0.001).

CONCLUSIONS

The clinical outcomes for DES and DCB treatment are similar in focal type of ISR lesions. For non-focal ISR, the treatment of DES showed a significant decrease in TLF which was mainly attributed to a lower incidence of CD-TLR.

Deforming Patient-Specific Models of Vascular Anatomies to Represent Stent Implantation via Extended Position Based Dynamics

PURPOSE

Angioplasty with stent placement is a widely used treatment strategy for patients with stenotic blood vessels. However, it is often challenging to predict the outcomes of this procedure for individual patients. Image-based computational fluid dynamics (CFD) is a powerful technique for making these predictions. To perform CFD analysis of a stented vessel, a virtual model of the vessel must first be created. This model is typically made by manipulating two-dimensional contours of the vessel in its pre-stent state to reflect its post-stent shape. However, improper contour-editing can cause invalid geometric artifacts in the resulting mesh that then distort the subsequent CFD predictions. To address this limitation, we have developed a novel shape-editing method that deforms surface meshes of stenosed vessels to create stented models.

METHODS

Our method uses physics-based simulations via Extended Position Based Dynamics to guide these deformations. We embed an inflating stent inside a vessel and apply collision-generated forces to deform the vessel and expand its cross-section.

RESULTS

We demonstrate that this technique is feasible and applicable for a wide range of vascular anatomies, while yielding clinically compatible results. We also illustrate the ability to parametrically vary the stented shape and create models allowing CFD analyses.

CONCLUSION

Our stenting method will help clinicians predict the hemodynamic results of stenting interventions and adapt treatments to achieve target outcomes for patients. It will also enable generation of synthetic data for data-intensive applications, such as machine learning, to support cardiovascular research endeavors.

A review of computational methodologies to predict the fractional flow reserve in coronary arteries with stenosis

Computational methodologies for predicting the fractional flow reserve (FFR) in coronary arteries with stenosis have gained significant attention due to their potential impact on healthcare outcomes. Coronary artery disease is a leading cause of mortality worldwide, prompting the need for accurate diagnostic and treatment approaches. The use of medical image-based anatomical vascular geometries in computational fluid dynamics (CFD) simulations to evaluate the hemodynamics has emerged as a promising tool in the medical field. This comprehensive review aims to explore the state-of-the-art computational methodologies focusing on the possible considerations. Key aspects include the rheology of blood, boundary conditions, fluid-structure interaction (FSI) between blood and the arterial wall, and multiscale modelling (MM) of stenosis. Through an in-depth analysis of the literature, the goal is to obtain an overview of the major achievements regarding non-invasive methods to compute FFR and to identify existing gaps and challenges that inform further advances in the field. This research has the major objective of improving the current diagnostic capabilities and enhancing patient care in the context of cardiovascular diseases.

Increased Serum CRP-Albumin Ratio is Independently Associated With In-Stent Restenosis After Carotid Artery Stenting

Atherosclerotic stenosis of the carotid artery contributes significantly to ischemic strokes. This study investigates the correlation between the C-reactive protein (CRP) to albumin ratio (CAR) and in-stent restenosis (ISR) in patients (n = 529) undergoing carotid artery stenting. Patients were categorized based on ISR occurrence. Cox regression analyses were performed to identify independent predictors of ISR. The ISR rate was 10.3%. Laboratory analysis revealed higher levels of uric acid, CRP, and CAR in the ISR group. Cox regression identified CAR as an independent predictor of ISR (Hazard ratio (HR): 1.13, 95% CI: 1.03-1.24, P = .01), along with diabetes and smoking. A CAR cut-off of 0.28 predicted ISR with 93% sensitivity and 89% specificity (Area under the curve (AUC): 0.945, 95% CI: 0.923-0.963, P < .001). This study establishes a significant association between CAR and ISR in carotid artery stenting patients. The inflammatory response, indicated by CAR, emerges as a crucial factor in ISR development. The study contributes valuable insights into predicting and preventing ISR, emphasizing the potential of CAR as a prognostic biomarker. This easily accessible and cost-effective biomarker could enhance ISR prediction and guide preventive strategies for high-risk patients.

A Review of Recent Advancements in Sensor-Integrated Medical Tools

A medical tool is a general instrument intended for use in the prevention, diagnosis, and treatment of diseases in humans or other animals. Nowadays, sensors are widely employed in medical tools to analyze or quantify disease-related parameters for the diagnosis and monitoring of patients' diseases. Recent explosive advancements in sensor technologies have extended the integration and application of sensors in medical tools by providing more versatile in vivo sensing capabilities. These unique sensing capabilities, especially for medical tools for surgery or medical treatment, are getting more attention owing to the rapid growth of minimally invasive surgery. In this review, recent advancements in sensor-integrated medical tools are presented, and their necessity, use, and examples are comprehensively introduced. Specifically, medical tools often utilized for medical surgery or treatment, for example, medical needles, catheters, robotic surgery, sutures, endoscopes, and tubes, are covered, and in-depth discussions about the working mechanism used for each sensor-integrated medical tool are provided.

A physics-informed deep learning framework for modeling of coronary in-stent restenosis

Machine learning (ML) techniques have shown great potential in cardiovascular surgery, including real-time stenosis recognition, detection of stented coronary anomalies, and prediction of in-stent restenosis (ISR). However, estimating neointima evolution poses challenges for ML models due to limitations in manual measurements, variations in image quality, low data availability, and the difficulty of acquiring biological quantities. An effective in silico model is necessary to accurately capture the mechanisms leading to neointimal hyperplasia. Physics-informed neural networks (PINNs), a novel deep learning (DL) method, have emerged as a promising approach that integrates physical laws and measurements into modeling. PINNs have demonstrated success in solving partial differential equations (PDEs) and have been applied in various biological systems. This paper aims to develop a robust multiphysics surrogate model for ISR estimation using the physics-informed DL approach, incorporating biological constraints and drug elution effects. The model seeks to enhance prediction accuracy, provide insights into disease progression factors, and promote ISR diagnosis and treatment planning. A set of coupled advection-reaction-diffusion type PDEs is constructed to track the evolution of the influential factors associated with ISR, such as platelet-derived growth factor (PDGF), the transforming growth factor- β (TGF- β ), the extracellular matrix (ECM), the density of smooth muscle cells (SMC), and the drug concentration. The nature of PINNs allows for the integration of patient-specific data (procedure-related, clinical and genetic, etc.) into the model, improving prediction accuracy and assisting in the optimization of stent implantation parameters to mitigate risks. This research addresses the existing gap in predictive models for ISR using DL and holds the potential to enhance patient outcomes through predictive risk assessment.

An Evaluation of the Duration of Oral Anticoagulant Use Among Patients Undergoing Endovascular Treatment of Nonthrombotic Iliac Vein Lesions

BACKGROUND

This study aimed to compare clinical outcomes associated with the duration of postoperative direct oral anticoagulant (DOACs) therapy in patients with nonthrombotic iliac vein lesions.

METHODS

We retrospectively analyzed 176 consecutive patients who underwent stenting for nonthrombotic iliac vein lesions between March 2018 and December 2021. In total, 99 and 77 patients were discharged on a 3-month and >3-month regimen of DOAC therapy, respectively. The primary cumulative endpoint was a composite of thrombotic complications, bleeding complications, primary patency, primary-assisted patency, and secondary patency within 1 year.

RESULTS

Patients undergoing 3-month and >3-month DOAC therapy were similar in age, sex, lesion site, symptoms, and average stent diameter and length. Upon multivariate analysis, the primary cumulative endpoint did not differ between the 2 groups (hazard ratio [HR]: 1.18; 95% confidence interval [CI]: 0.42-3.30; P = 0.76). Moreover, the primary patency at 1 year did not differ between the groups (HR: 1.50; 95% CI: 0.14-16.54; P = 0.74). Furthermore, there were no discernible differences in the secondary endpoints of bleeding complications (HR: 0.66; 95% CI: 0.22-1.96; P = 0.45) or thrombotic complications (HR: 1.79; 95% CI: 0.55-5.80; P = 0.34) between the groups.

CONCLUSIONS

The 3-month regimen of DOAC therapy showed a similar risk of postoperative thrombosis and bleeding when compared to longer DOAC therapy durations over the course of 1 year following endovascular intervention. This could be a preferred option for patients with a higher estimated bleeding risk after venous stenting.

Diagnostic Performance of Machine Learning-Derived Radiomics Signature of Pericoronary Adipose Tissue in Coronary Computed Tomography Angiography for Coronary Artery In-Stent Restenosis

RATIONALE AND OBJECTIVES

Coronary inflammation can alter the perivascular fat phenotype. Hence, we aimed to assess the diagnostic performance of radiomics features of pericoronary adipose tissue (PCAT) in coronary computed tomography angiography (CCTA) for in-stent restenosis (ISR) after percutaneous coronary intervention.

MATERIALS AND METHODS

In this study, 165 patients with 214 eligible vessels were included, and ISR was found in 79 vessels. After evaluating clinical and stent characteristics, peri-stent fat attenuation index, and PCAT volume, 1688 radiomics features were extracted from each peri-stent PCAT segmentation. The eligible vessels were randomly categorized into training and validation groups in a ratio of 7:3. After performing feature selection using Pearson's correlation, F test, and least absolute shrinkage and selection operator analysis, radiomics models and integrated models that combined selected clinical features and Radscore were established using five different machine learning algorithms (logistic regression, support vector machine, random forest, stochastic gradient descent, and XGBoost). Subgroup analysis was performed using the same method for patients with stent diameters of ≤ 3 mm.

RESULTS

Nine significant radiomics features were selected, and the areas under the curves (AUCs) for the radiomics model and the integrated model were 0.69 and 0.79, respectively, for the validation group. The AUCs of the subgroup radiomics model based on 15 selected radiomics features and the subgroup integrated model were 0.82 and 0.85, respectively, for the validation group, which showed better diagnostic performance.

CONCLUSION

CCTA-based radiomics signature of PCAT has the potential to identify coronary artery ISR without additional costs or radiation exposure.

Gas station in blood vessels: An endothelium mimicking, self-sustainable nitric oxide fueling stent coating for prevention of thrombosis and restenosis

Stenting is the primary treatment for vascular obstruction-related cardiovascular diseases, but it inevitably causes endothelial injury which may lead to severe thrombosis and restenosis. Maintaining nitric oxide (NO, a vasoactive mediator) production and grafting endothelial glycocalyx such as heparin (Hep) onto the surface of cardiovascular stents could effectively reconstruct the damaged endothelium. However, insufficient endogenous NO donors may impede NO catalytic generation and fail to sustain cardiovascular homeostasis. Here, a dopamine-copper (DA-Cu) network-based coating armed with NO precursor L-arginine (Arg) and Hep (DA-Cu-Arg-Hep) is prepared using an organic solvent-free dipping technique to form a nanometer-thin coating onto the cardiovascular stents. The DA-Cu network adheres tightly to the surface of stents and confers excellent NO catalytic activity in the presence of endogenous NO donors. The immobilized Arg functions as a NO fuel to generate NO via endothelial nitric oxide synthase (eNOS), while Hep works as eNOS booster to increase the level of eNOS to decompose Arg into NO, ensuring a sufficient supply of NO even when endogenous donors are insufficient. The synergistic interaction between Cu and Arg is analogous to a gas station to fuel NO production to compensate for the insufficient endogenous NO donor in vivo. Consequently, it promotes the reconstruction of natural endothelium, inhibits smooth muscle cell (SMC) migration, and suppresses cascading platelet adhesion, preventing stent thrombosis and restenosis. We anticipate that our DA-Cu-Arg-Hep coating will improve the quality of life of cardiovascular patients through improved surgical follow-up, increased safety, and decreased medication, as well as revitalize the stenting industry through durable designs.

Cardiovascular Applications of Photon-Counting CT Technology: A Revolutionary New Diagnostic Step

Photon-counting computed tomography (PCCT) is an emerging technology that can potentially transform clinical CT imaging. After a brief description of the PCCT technology, this review summarizes its main advantages over conventional CT: improved spatial resolution, improved signal and contrast behavior, reduced electronic noise and artifacts, decreased radiation dose, and multi-energy capability with improved material discrimination. Moreover, by providing an overview of the existing literature, this review highlights how the PCCT benefits have been harnessed to enhance and broaden the diagnostic capabilities of CT for cardiovascular applications, including the detection of coronary artery calcifications, evaluation of coronary plaque extent and composition, evaluation of coronary stents, and assessment of myocardial tissue characteristics and perfusion.

Genetic Variants in PHACTR1 & LPL Mediate Restenosis Risk in Coronary Artery Patients

Background and Objective

Coronary artery disease (CAD) is a major cause of death worldwide. Revascularization via stent placement or coronary artery bypass grafting (CABG) are standard treatments for CAD. Despite a high success rate, these approaches are associated with long-term failure due to restenosis. Risk factors associated with restenosis were investigated using a case-control association study design.

Methods

Five thousand two hundred and forty-two patients were enrolled in this study and were assigned as follows: Stenosis Group: 3570 patients with CAD >50% without a prior stent or CABG (1394 genotyped), and Restenosis Group: 1672 patients with CAD >50% and prior stent deployment or CABG (705 genotyped). Binomial regression models were applied to investigate the association of restenosis with diabetes, hypertension, and dyslipidemia. The genetic association with restenosis was conducted using PLINK 1.9.

Results

Dyslipidemia is a major risk factor (Odds Ratio (OR) = 2.14, P-value <0.0001) for restenosis particularly among men (OR = 2.32, P < 0.0001), while type 2 diabetes (T2D) was associated with an increased risk of restenosis in women (OR = 1.36, P = 0.01). The rs9349379 (PHACTR1) and rs264 (LPL) were associated with an increased risk of restenosis in our patients. PHACTR1 variant was associated with increased risk of restenosis mainly in women and in diabetic patients, while the LPL variant was associated with increased risk of restenosis in men.

Conclusion

The rs9349379 in PHACTR1 gene is significantly associated with restenosis, this association is more pronounced in women and in diabetic patients. The rs264 in LPL gene was associated with increased risk of restenosis in male patients.

Cardiotonic Pills® protects from myocardial fibrosis caused by in stent restenosis in miniature pigs

BACKGROUND

Stent implantation has been increasingly applied for the treatment of obstructive coronary artery disease, which, albeit effective, often harasses patients by in-stent restenosis (ISR).

PURPOSE

The present study was to explore the role of compound Chinese medicine Cardiotonic Pills® (CP) in attenuating ISR-evoked myocardial injury and fibrosis.

STUDY DESIGN

Chinese miniature pigs were used to establish ISR model by implanting obsolete degradable stents into coronary arteries. Quantitative coronary angiography (QCA) was performed to confirm the success of the model.

METHODS

CP was given at 0.2 g/kg daily for 30 days after ISR. On day 30 and 60 after stent implantation, the myocardial infarct and myocardial blood flow (MBF) were assessed. Myocardial histology was evaluated by hematoxylin-eosin and Masson's trichrome staining. The content of ATP, MPO, and the activity of mitochondrial respiratory chain complex Ⅳ were determined by ELISA. Western blot was performed to assess the expression of ATP5D and related signaling proteins, and the mediators of myocardial fibrosis.

RESULTS

Treatment with CP diminished myocardial infarct size, retained myocardium structure, attenuated myocardial fibrosis, and restored MBF. CP ameliorated energy metabolism disorder, attenuated TGFβ1 up-regulation and reversed its downstream gene expression, such as Smad6 and Smad7, and inhibited the increased expression of MCP-1, PR S19, MMP-2 and MMP-9.

CONCLUSION

CP effectively protects myocardial structure and function from ISR challenge, possibly by regulating energy metabolism via inactivation of RhoA/ROCK signaling pathway and inhibition of monocyte chemotaxis and TGF β1/Smads signaling pathway.

High-Resolution Vessel Wall MRI in Assessing Postoperative Restenosis of Intracranial Atherosclerotic Disease Before Drug-Coated Balloon Treatment: An Outcome Prediction Study

BACKGROUND

Postoperative restenosis frequently occurs in intracranial atherosclerotic disease (ICAD) patients after drug-coated balloon (DCB) treatment. However, high-risk plaques associated with postoperative restenosis remain to be explored.

PURPOSE

To assess whether high-resolution vessel wall MRI (HR-VWI) contributes to the identification of high-risk plaques associated with postoperative restenosis before DCB treatment.

STUDY TYPE

Retrospective.

SUBJECTS

A total of 70 patients with ICAD who underwent DCB treatment.

FIELD STRENGTH/SEQUENCE

3.0 T; magnetic resonance angiography, HR-VWI.

ASSESSMENT

All patients underwent HR-VWI examination prior to DCB treatment. Digital subtraction angiography (DSA) measurement was assessed 6 months (±1 month) after operation to determine the vessel restenosis, classifying patients into three groups of no stenosis, mild stenosis (<50%), and restenosis (>50%). Clinical factors and HR-VWI characteristics, including vessel and lumen area at maximal lumen narrowing (MLN), plaque area and length, degree of stenosis, plaque burden, remodeling index, and enhancement amplitude, were compared among three groups. Clinical factors and HR-VWI characteristics were separately evaluated for the association with postoperative restenosis.

STATISTICAL TESTS

Kolmogorov-Smirnov test, intra-class correlation coefficient, Kruskal Wallis H test, Mann-Whitney U test, receiver operating characteristic (ROC) curve, multivariable linear regression analysis. P-values <0.05 was considered statistically significant.

RESULTS

During the follow-up DSA measurement, 13 lesions (18.5%) showed restenosis. With HR-VWI, significant differences among three groups were observed in plaque length, lumen area of MLN, degree of stenosis, enhancement amplitude, and plaque burden. In ROC analysis, plaque length (area under the curve [AUC] = 0.809), and enhancement amplitude (AUC = 0.880) provided higher efficacy in identification of high-risk plaques associated with postoperative restenosis than degree of stenosis (AUC = 0.746) and plaque burden (AUC = 0.759). Multivariable linear regression analysis showed that plaque length and enhancement amplitude were independent prognostic factors of postoperative restenosis.

DATA CONCLUSION

HR-VWI has the potential to identify high-risk plaques in ICAD patients before DCB treatment.

LEVEL OF EVIDENCE

4 TECHNICAL EFFICACY: Stage 2.

Caffeic Acid-Grafted PLGA as a Novel Material for the Design of Fluvastatin-Eluting Nanoparticles for the Prevention of Neointimal Hyperplasia

Drug-eluting nanoparticles (NPs) administered by an eluting balloon represent a novel tool to prevent restenosis after angioplasty, even if the selection of the suitable drug and biodegradable material is still a matter of debate. Herein, we provide the proof of concept of the use of a novel material obtained by combining the grafting of caffeic acid or resveratrol on a poly(lactide-co-glycolide) backbone (g-CA-PLGA or g-RV-PLGA) and the pleiotropic effects of fluvastatin chosen because of its low lipophilic profile which is challenging for the encapsulation in NPs and delivery to the artery wall cells. NPs made of such materials are biocompatible with macrophages, human smooth muscle cells (SMCs), and endothelial cells (ECs). Their cellular uptake is demonstrated and quantified by confocal microscopy using fluorescent NPs, while their distribution in the cytoplasm is verified by TEM images using NPs stained with an Ag-PVP probe appositely synthetized. g-CA-PLGA assures the best control of the FLV release from NP sizing around 180 nm and the faster SMC uptake, as demonstrated by confocal analyses. Interestingly and surprisingly, g-CA-PLGA improves the FLV efficacy to inhibit the SMC migration, without altering its effects on EC proliferation and migration. The improved trophism of NPs toward SMCs, combined with the excellent biocompatibility and low modification of the microenvironment pH upon polymer degradation, makes g-CA-PLGA a suitable material for the design of drug-eluting balloons.

In-Stent Restenosis

In-stent restenosis (ISR) remains a potential complication after percutaneous coronary intervention, even in the era of drug-eluting stents, and its treatment remains suboptimal. Neoatherosclerosis is an important component of the pathology of ISR and is accelerated in drug-eluting stents compared with bare-metal stents. Coronary angiography is the gold standard for evaluating the morphology of ISR, although computed tomography angiography is emerging as an alternative noninvasive modality to evaluate the presence of ISR. Drug-coated balloons and stent reimplantation are the current mainstays of treatment for ISR, and the choice of treatment should be based on clinical background and lesion morphology.

Association of serum apoA-I with in-stent restenosis in coronary heart disease

Background

Despite use of drug-eluting stents (DES), in-stent restenosis (ISR) continues adversely affecting clinical outcomes of patients undergoing percutaneous coronary intervention (PCI). Apolipoprotein A-I (apoA-I) has athero-protective effects. However, there is a paucity of clinical data regarding the association between apoA-I and ISR. We sought to investigate whether serum apoA-I is related to ISR after DES-based PCI.

Methods

In this retrospective case control study, 604 consecutive patients who underwent DES implantation before were enrolled. Patients who underwent repeat angiography within 12 months were included in the early ISR study (n = 205), while those beyond 12 months were included in the late ISR study (n = 399). ISR was defined as the presence of > 50% diameter stenosis at the stent site or at its edges. Clinical characteristics were compared between ISR and non-ISR patients in the early and late ISR study, respectively, after adjusting for confounding factors by multivariate logistic regression, stratified analysis, and propensity score matching. The predictive value was assessed by univariate and multivariate logistic regression analysis, receiver operating characteristic (ROC) curve analysis, and quartile analysis.

Results

In the early ISR study, 8.8% (18 of 205) patients developed ISR. Serum apoA-I in the ISR group was lower than that in the non-ISR group (1.1 ± 0.26 vs. 1.24 ± 0.23, P < 0.05). On multivariate logistic regression analysis, apoA-I was an independent risk factor for early ISR. Incidence of early ISR showed negative correlation with apoA-I and could be predicted by the combined use of apoA-I and glycosylated hemoglobin (HbA1c) level. In the late ISR study, 21.8% (87 of 399) patients developed ISR. On subgroup analysis, late ISR showed negative correlation with apoA-I irrespective of intensive lipid lowering; on multivariate logistic regression analysis, apoA-I was also an independent risk factor for late ISR. In patients with intensive lipid lowering, combined use of apoA-I, stenting time, and diabetes predicted the incidence of late ISR.

Conclusions

ApoA-I was an independent risk factor for ISR, and showed a negative correlation with ISR after DES-based PCI. Combined use of apoA-I and clinical indicators may better predict the incidence of ISR under certain circumstances.

Predictors of Stent Restenosis in Han and Uygur Patients with Coronary Heart Disease after PCI in the Xinjiang Region

Background

Stent restenosis after PCI seriously affects the efficacy and prognosis; therefore, the study of ISR risk factors has become an urgent topic to be solved.

Objective

To investigate the risk factors for in-stent restenosis (ISR) after percutaneous coronary intervention (PCI) in Han and Uygur patients with coronary heart disease.

Methods

The clinical data of 345 Han and 127 Uygur patients who underwent intracoronary stent implantation were divided into an ISR group and a non-ISR group. The general clinical data, laboratory indicators, and coronary artery lesions were compared.

Results

Age (OR = 1.040, 95% CI: 1.006∼1.075), triglycerides (OR = 1.440, 95% CI: 1.050∼1.973), total cholesterol (OR = 5.256, 95% CI: 2.826∼9.773), and ApoB (OR = 137.540, 95% CI: 11.364∼899.455) were independent risk factors for ISR after PCI in the Han patients, while ApoAI (OR = 0.002, 95% CI: 0.001∼0.011), MCV (OR = 0.824, 95% CI: 0.744∼0.911), MCH (OR = 0.421, 95% CI: 0.324∼0.548), and MCHC (OR = 0.934, 95% CI: 0.903∼0.965) were protective factors of ISR after PCI in Han patients, and the logistic regression equation composed of various factors predicted that the area under the ROC curve of ISR was 0.905. ApoB (OR = 11.571, 95% CI: 1.667∼80.340), Gensini score (OR = 1.017, 95% CI: 1.003∼1.031), and diabetes history (OR = 3.474, 95% CI: 1.189∼10.151) were independent risk factors for ISR after PCI in Uygur patients, and the area under ROC curve of ISR predicted by logistic regression equation is 0.807. The predictive efficiency of the Gensini score and ApoB level for ISR in Uygur patients was higher than that in Han, while the predictive efficiency of levels of ApoAI and MCH for ISR in Han patients was higher than that in Uygur (P < 0.05).

Conclusion

The independent risk factors for ISR after PCI in Han and Uygur patients in Xinjiang are different.

Polymer–Metal Composite Healthcare Materials: From Nano to Device Scale

Metals have been investigated as biomaterials for a wide range of medical applications. At nanoscale, some metals, such as gold nanoparticles, exhibit plasmonics, which have motivated researchers’ focus on biosensor development. At the device level, some metals, such as titanium, exhibit good physical properties, which could allow them to act as biomedical implants for physical support. Despite these attractive features, the non-specific delivery of metallic nanoparticles and poor tissue–device compatibility have greatly limited their performance. This review aims to illustrate the interplay between polymers and metals, and to highlight the pivotal role of polymer–metal composite/nanocomposite healthcare materials in different biomedical applications. Here, we revisit the recent plasmonic engineered platforms for biomolecules detection in cell-free samples and highlight updated nanocomposite design for (1) intracellular RNA detection, (2) photothermal therapy, and (3) nanomedicine for neurodegenerative diseases, as selected significant live cell–interactive biomedical applications. At the device scale, the rational design of polymer–metallic medical devices is of importance for dental and cardiovascular implantation to overcome the poor physical load transfer between tissues and devices, as well as implant compatibility under a dynamic fluidic environment, respectively. Finally, we conclude the treatment of these innovative polymer–metal biomedical composite designs and provide a future perspective on the aforementioned research areas.

Effect of expanded polytetrafluoroethylene thickness on paclitaxel release and edge stenosis in stent graft

Stent grafts have been widely used to treat lower extremity arterial stenosis or occlusion. However, there are major issues with edge stenosis and loss of patency over time. Paclitaxel-coated stent grafts have been proven to be effective in preventing edge stenosis, but the insufficient amounts of paclitaxel released may limit the effectiveness of drug-eluting stent grafts. In this study, we examined whether paclitaxel-coated expanded polytetrafluoroethylene (ePTFE) stent graft thickness influences paclitaxel release properties and inhibits edge stenosis. Low-, medium-, and high-thickness paclitaxel-coated stent grafts were prepared by varying the thickness of inner and outer ePTFE layers. Surface morphologies of the stent grafts were analyzed using a scanning electron microscope. The stent grafts were then implanted in the iliac arteries of 20 healthy swine. Twelve pigs were used to assess edge stenosis, and digital subtraction angiography was performed at day 30 (n = 4), 90 (n = 4), and 180 (n = 4). Histological evaluation of the treated arteries was also performed. Eight pigs were used for pharmacokinetic analysis, and the treated arteries were obtained at day 1 (n = 2), 30 (n = 2), 90 (n = 2) and 180 (n = 2). Scanning electron microscopy confirmed that the mean pore size of the stent grafts decreased with increasing thickness. The results of angiographic and histological evaluation demonstrated that low-thickness ePTFE-stent grafts resulted in edge stenosis and apparent intimal hyperplasia at 180 days, whereas for medium-thickness ePTFE-stent grafts, no obvious edge stenosis and intimal hyperplasia was noted in the similar time period. The results of pharmacokinetic evaluation showed that at 180 days, the paclitaxel concentration of treated arteries of the medium group was 36 ± 53 ng/g, while concentrations in the low group was not detectable. Stent grafts with increased ePTFE thickness appear to allow for more delayed release of paclitaxel compared to low-thickness ePTFEs.

Coronary intravascular brachytherapy for in-stent restenosis: A review of the contemporary literature

Intracoronary stent restenosis (ISR) is a clinically relevant challenge in the modern era. Heterogeneity in patient- and lesion-specific factors can further compound this clinical challenge. Coronary intravascular brachytherapy (IVBT) was the standard therapeutic approach for ISR prior to the advent of drug-eluting stents (DES). Despite prospective data describing the superiority of DES over IVBT for treating de novo ISR, IVBT remains a treatment option for patients with complex disease. The purpose of this review is to evaluate the historical and contemporary literature surrounding IVBT in order to elucidate its role in modern cardiac care and to describe opportunities for future investigations to improve patient selection. Herein, we provide a review of the contemporary literature describing IVBT as a safe and effective treatment option for patients with recurrent, refractory ISR after multilayer DES and no good surgical or mechanical option. Combination therapy with emerging technologies such as DCBs may further increase efficacy.

Bioimpedance Sensing of Implanted Stent Occlusions: Smart Stent

Coronary artery disease is one of the most common diseases in developed countries and affects a large part of the population of developing countries. Preventing restenosis in patients with implanted stents is an important current medical problem. The purpose of this work is to analyse the viability of bioimpedance sensing to detect the formation of atheromatous plaque in an implantable stent. Simulations in COMSOL Multiphysics were performed to analyse the performance of the proposed bioimpedance sensing system, based on the Sheffield technique. Both non-pathological and pathological models (with atheromatous plaque), including the flow of blood were considered. Simulations with the non-pathological model showed a homogeneous distribution of the measured current intensity in the different electrodes, for every configuration. On the other hand, simulations with the pathological model showed a significant decrease of the measured current intensity in the electrodes close to the simulated atheromatous plaque. The presence of the atheromatous plaque can, therefore, be detected by the system with a simple algorithm, avoiding the full reconstruction of the image and the subsequent computational processing requirements.

Intravascular Lithotripsy in Calcified Coronary Lesions: A Single-Center Experience in “Real-World” Patients

Objectives

This study aims to describe the outcome of intravascular lithotripsy (IVL) when used with different indications and to assess the short- and long-term outcomes of IVL-facilitated percutaneous coronary intervention (PCI).

Background

Intravascular lithotripsy can improve the results of PCI of calcified coronary lesions with a low rate of periprocedural complications.

Methods

A total of 105 consecutive patients with 110 calcified lesions underwent IVL. A total of 87 de novo lesions were treated by IVL with the following indications: 25 before attempting other balloon-based devices (primary IVL), 51 after the failure of non-compliant balloon dilatation (secondary IVL), and 11 after stent implantation because of stent under expansion (bailout IVL). In 23 lesions, IVL was used for the treatment of in-stent restenosis (ISR). Effectiveness (angiographic success) and safety [major adverse cardiovascular events (MACEs) and IVL-related procedural complications] endpoints were assessed.

Results

Angiographic success was achieved in 84.6% of lesions. Early MACEs were periprocedural MI only, ranging from 6.7 to 20% depending on MI definition. The flow-limiting dissections rate was 2.7%. A total of five (4.5%) IVL balloons ruptured during treatment with subsequent vessel perforation in 1 case. MACEs at 12 months were 13.3%, with TLR occurring in 8 lesions (12% primary IVL, 0% secondary IVL, 0% bailout IVL, and 21.7% IVL for ISR, p = 0.002).

Conclusion

Treatment of calcified coronary lesions with IVL in a “real-world” setting can be performed with high success, low rate of procedural complications, and an acceptable MACEs rate. Target lesion failure may be more frequent when IVL is performed for the treatment of ISR due to calcium-mediated stent under expansion.

Current and Future Applications of Artificial Intelligence in Coronary Artery Disease

Cardiovascular diseases (CVDs) carry significant morbidity and mortality and are associated with substantial economic burden on healthcare systems around the world. Coronary artery disease, as one disease entity under the CVDs umbrella, had a prevalence of 7.2% among adults in the United States and incurred a financial burden of 360 billion US dollars in the years 2016–2017. The introduction of artificial intelligence (AI) and machine learning over the last two decades has unlocked new dimensions in the field of cardiovascular medicine. From automatic interpretations of heart rhythm disorders via smartwatches, to assisting in complex decision-making, AI has quickly expanded its realms in medicine and has demonstrated itself as a promising tool in helping clinicians guide treatment decisions. Understanding complex genetic interactions and developing clinical risk prediction models, advanced cardiac imaging, and improving mortality outcomes are just a few areas where AI has been applied in the domain of coronary artery disease. Through this review, we sought to summarize the advances in AI relating to coronary artery disease, current limitations, and future perspectives.

Deletion of Smooth Muscle Lethal Giant Larvae 1 Promotes Neointimal Hyperplasia in Mice

Vascular smooth muscle cell (VSMC) proliferation and migration contribute to neointimal hyperplasia after injury, which causes vascular remodeling related to arteriosclerosis, hypertension, and restenosis. Lethal giant larvae 1 (LGL1) is a highly conserved protein and plays an important role in cell polarity and tumor suppression. However, whether LGL1 affects neointimal hyperplasia is still unknown. In this study, we used smooth muscle-specific LGL1 knockout (LGL1^SMKO) mice generated by cross-breeding LGL1^flox/flox mice with α-SMA-Cre mice. LGL1 expression was significantly decreased during both carotid artery ligation in vivo and PDGF-BB stimulation in vitro. LGL1 overexpression inhibited the proliferation and migration of VSMCs. Mechanistically, LGL1 could bind with signal transducer and activator of transcription 3 (STAT3) and promote its degradation via the proteasomal pathway. In the carotid artery ligation animal model, smooth muscle-specific deletion of LGL1 accelerated neointimal hyperplasia, which was attenuated by the STAT3 inhibitor SH-4-54. In conclusion, LGL1 may inhibit neointimal hyperplasia by repressing VSMC proliferation and migration via promoting STAT3 proteasomal degradation.

Computational analysis of the effects of geometric irregularities on the interaction of an additively manufactured 316L stainless steel stent and a coronary artery

Customized additively manufactured (laser powder bed fused (L-PBF)) stents could improve the treatment of complex lesions by enhancing stent-artery conformity. However, geometric irregularities inherent for L-PBF stents are expected to influence not only their mechanical behavior but also their interaction with the artery. In this study, the influence of geometrical irregularities on stent-artery interaction is evaluated within a numerical framework. Thus, computed arterial stresses induced by a reconstructed L-PBF stent model are compared to those induced by the intended stent model (also representing a stent geometry obtained from conventional manufacturing processes) and a modified CAD stent model that accounts for the increased strut thickness inherent for L-PBF stents. It was found that, similar to conventionally manufactured stents, arterial stresses are initially related to the basic stent design/topology, with the highest stresses occurring at the indentations of the stent struts. Compared to the stent CAD model, the L-PBF stent induces distinctly higher and more maximum volume stresses within the plaque and the arterial wall. In return, the modified CAD model overestimates the arterial stresses induced by the L-PBF stent due to its homogeneously increased strut thickness and thus its homogeneously increased geometric stiffness compared with the L-PBF stent. Therefore, the L-PBF-induced geometric irregularities must be explicitly considered when evaluating the L-PBF stent-induced stresses because the intended stent CAD model underestimates the arterial stresses, whereas the modified CAD model overestimates them. The arterial stresses induced by the L-PBF stent were still within the range of values reported for conventional stents in literature, suggesting that the use of L-PBF stents is conceivable in principle. However, because geometric irregularities, such as protruding features from the stent surface, could potentially damage the artery or lead to premature stent failure, further improvement of L-PBF stents is essential.

Influences of Stent Design on In-Stent Restenosis and Major Cardiac Outcomes: A Scoping Review and Meta-Analysis

Thanks to the developments in implantable biomaterial technologies, invasive operating procedures, and widespread applications especially in vascular disease treatment, a milestone for interventional surgery was achieved with the introduction of vascular stents. Despite vascular stents providing a solution for embolisms, this technology includes various challenges, such as mechanical, electro-chemical complications, or in-stent restenosis (ISR) risks with long-term usage. Therefore, further development of biomaterial technologies is vital to overcome such risks and problems. For this purpose, recent research has focused mainly on the applications of surface modification techniques on biomaterials and vascular stents to increase their hemocompatibility. ISR risk has been reduced with the development and prevalent usage of the art technology stent designs of drug-eluting and biodegradable stents. Nevertheless, their problems have not been overcome completely. Furthermore, patients using drug-eluting stents are faced with further clinical challenges. Therefore, the bare metal stent, which is the first form of the vascular stent technology and includes the highest ISR risk, is still in common usage for vascular treatment applications. For this reason, further research is necessary to solve the remaining vital problems. In this scoping review, stent-based major cardiac events including ISR are analyzed depending on different designs and material selection in stent manufacturing. Recent and novel approaches to overcome such challenges are stated in detail.

Relationship between Lp-PLA2 and in-stent restenosis after coronary stenting: a 3-year follow-up study

BACKGROUND AND AIMS

Coronary in-stent restenosis (ISR) is an important complication of percutaneous coronary intervention (PCI). However, the relationship between lipoprotein associated phospholipase A2 (Lp-PLA2) level and ISR after PCI is rarely reported. This study aims to explore the relationship between Lp-PLA2 and the occurrence of ISR at post-PCI and its predictive value for ISR.

METHODS AND RESULTS

Plasma Lp-PLA2 mass were measured in 847 patients planting 1262 stents and evaluated along with known risk indicators. One-year angiographic follow-up showed that baseline elevated Lp-PLA2 mass was strongly associated with early restenosis (95% CI = 1.062-3.050, P < 0.05). Beyond the first year, the occurrence of late restenosis (95% CI = 1.043-3.214, P < 0.05) was significantly larger in the elevated Lp-PLA2 group. Kaplan-Meier analysis after three-year clinical follow up suggested that Lp-PLA2 mass did add the positive effect on the occurrence of major adverse cardiovascular events (MACEs).

CONCLUSION

In conclusion, increased baseline plasma Lp-PLA2 predicts increased risks of re-stenosis and MACEs, which may be a novel biomarker for predicting ISR and MACEs.

The 1-Year Safety and Efficacy Outcomes of Magmaris, Novel Magnesium Bioresorbable Vascular Scaffolds in Diabetes Mellitus Patients with Acute Coronary Syndrome

Background: Diabetes mellitus (DM) is one of the major risk factors contributing to Acute Coronary Syndromes (ACS) and is associated with an increased risk of adverse clinical outcomes following percutaneous coronary intervention (PCI), even when the second generation of drug-eluting stents (DES) is used. In order to overcome the disadvantages of permanent caging of a vessel with metallic DES, bioresorbable scaffold (BRS) technology has been recently developed. However, the prognosis of patients with DM and ACS treated with PCI via subsequent implantation of Magmaris (Biotronik, Berlin, Germany)—a novel magnesium-bioresorbable scaffold—is poorly investigated. Methods: A total of 193 consecutive subjects with non-ST elevation acute coronary syndrome (NSTE-ACS) who, from October 2016 to March 2020, received one or more Magmaris scaffolds were enrolled in this study. The diabetic group was compared with non-diabetic subjects. Results: There were no significant differences in the occurrence of primary endpoints (cardiovascular death, myocardial infarction, and in-stent thrombosis) and principal secondary endpoints (target-lesion failure, scaffold restenosis, death from any reason, and other cardiovascular events) between the two compared groups in a 1-year follow-up period. Conclusions: The early 1-year-outcome of magnesium bioresorbable scaffold (Magmaris) seems to be favorable and suggests that this novel BRS is safe and effective in subjects with NSTE-ACS and co-existing DM.

Predictive value of miRNA-126 on in-stent restenosis in patients with coronary heart disease: A protocol for meta-analysis and bioinformatics analysis

BACKGROUND

In-stent restenosis (ISR) is one of the most important complications and impacts the long-term effects after percutaneous coronary intervention (PCI) in patients with coronary heart disease (CHD). Related studies have revealed that microRNA (miRNA) can predict ISR in CHD patients. MiRNA-126 may be a potential biomarker for the diagnosis of ISR. However, the accuracy of miRNA-126 in the diagnosis of ISR is still controversial. Therefore, this study carried out meta-analysis to further evaluate the accuracy of miRNA-126 in the diagnosis of ISR. At the same time, bioinformatics is used to predict the target genes and miRNA-126 may be involved in regulation, so as to provide theoretical support for the precise treatment of CHD.

METHODS

The literatures on the miRNA-126 diagnosis of ISR in CHD patients were collected by searching on computer through China National Knowledge Infrastructure, Wanfang, China Biology Medicine disc, PubMed, EMBASE, Cochrane Library and Web of Science. The retrieval time is set to build the database until April 2021. The meta-analysis of the literatures that meet the quality standards was conducted by Stata 16.0 software. TargetScan database, PicTar database, miRanda database, and miRDB database were used to predict miRNA-126 intersection target genes. Gene Ontology (GO) functional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) signal pathway enrichment analysis of miRNA-126 target genes were performed by using DAVID database. STRING database was applied to analyze the protein-protein interaction (PPI) network of miRNA-126 target genes. The "Networkanalyzer" function of Cytoscape3.7.2 software is adopted to analyze the network topology attributes, so as to find out the core genes of PPI network.

RESULTS

The results of this meta-analysis will be submitted to a peer-reviewed journal for publication.

CONCLUSION

In this study, meta-analysis and bioinformatics analysis were adopted to further evaluate the accuracy of miRNA-126 in the diagnosis of ISR in CHD patients, and to explore the mechanism of the action of miRNA-126 and understand related pathways.

ETHICS AND DISSEMINATION

The private information from individuals will not be published. This systematic review also should not damage participants' rights. Ethical approval is not available. The results may be published in a peer-reviewed journal or disseminated in relevant conferences.

OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/9FMR5.

Clinical characteristics of early and late drug-eluting stent in-stent restenosis and mid-term prognosis after repeated percutaneous coronary intervention

Background:

The mechanism and characteristics of early and late drug-eluting stent in-stent restenosis (DES-ISR) have not been fully clarified. Whether there are different outcomes among those patients being irrespective of their repeated treatments remain a knowledge gap.

Methods:

A total of 250 patients who underwent initial stent implantation in our hospital, and then were readmitted to receive treatment for the reason of recurrent significant DES-ISR in 2016 were involved. The patients were categorized as early ISR (<12 months; E-ISR; n = 32) and late ISR (≥12 months; L-ISR; n = 218). Associations between patient characteristics and clinical performance, as well as clinical outcomes after a repeated percutaneous coronary intervention (PCI) were evaluated. Primary composite endpoint of major adverse cardiac events (MACEs) included cardiac death, non-fatal myocardial infarction (MI), or target lesion revascularization (TLR).

Results:

Most baseline characteristics are similar in both groups, except for the period of ISR, initial pre-procedure thrombolysis in myocardial infarction, and some serum biochemical indicators. The incidence of MACE (37.5% vs. 5.5%; P < 0.001) and TLR (37.5% vs. 5.0%; P < 0.001) is higher in the E-ISR group. After multivariate analysis, E-ISR (odds ratio [OR], 13.267; [95% CI 4.984–35.311]; P < 0.001) and left ventricular systolic dysfunction (odds ratio [OR], 6.317; [95% CI 1.145–34.843]; P = 0.034) are the independent predictors for MACE among DES-ISR patients in the mid-term follow-up of 12 months.

Conclusions:

Early ISR and left ventricular systolic dysfunction are associated with MACE during the mid-term follow-up period for DES-ISR patients. The results may benefit the risk stratification and secondary prevention for DES-ISR patients in clinical practice.

Risk factors associated with major adverse cardiac and cerebrovascular events following percutaneous coronary intervention: a 10-year follow-up comparing random survival forest and Cox proportional-hazards model

Background

Due to the limited number of studies with long term follow-up of patients undergoing Percutaneous Coronary Intervention (PCI), we investigated the occurrence of Major Adverse Cardiac and Cerebrovascular Events (MACCE) during 10 years of follow-up after coronary angioplasty using Random Survival Forest (RSF) and Cox proportional hazards models.

Methods

The current retrospective cohort study was performed on 220 patients (69 women and 151 men) undergoing coronary angioplasty from March 2009 to March 2012 in Farchshian Medical Center in Hamadan city, Iran. Survival time (month) as the response variable was considered from the date of angioplasty to the main endpoint or the end of the follow-up period (September 2019). To identify the factors influencing the occurrence of MACCE, the performance of Cox and RSF models were investigated in terms of C index, Integrated Brier Score (IBS) and prediction error criteria.

Results

Ninety-six patients (43.7%) experienced MACCE by the end of the follow-up period, and the median survival time was estimated to be 98 months. Survival decreased from 99% during the first year to 39% at 10 years' follow-up. By applying the Cox model, the predictors were identified as follows: age (HR = 1.03, 95% CI 1.01–1.05), diabetes (HR = 2.17, 95% CI 1.29–3.66), smoking (HR = 2.41, 95% CI 1.46–3.98), and stent length (HR = 1.74, 95% CI 1.11–2.75). The predictive performance was slightly better by the RSF model (IBS of 0.124 vs. 0.135, C index of 0.648 vs. 0.626 and out-of-bag error rate of 0.352 vs. 0.374 for RSF). In addition to age, diabetes, smoking, and stent length, RSF also included coronary artery disease (acute or chronic) and hyperlipidemia as the most important variables.

Conclusion

Machine-learning prediction models such as RSF showed better performance than the Cox proportional hazards model for the prediction of MACCE during long-term follow-up after PCI.

Distribution and Dynamic Changes in Matrix Metalloproteinase (MMP)-2, MMP-9, and Collagen in an In Stent Restenosis Process

OBJECTIVE

The aim of this study was to observe the spatial distribution and dynamic changes of matrix metalloproteinase (MMP)-2, MMP-9, and collagen in in stent restenosis (ISR) and to explore their influence on ISR.

METHODS

Sixty Z type stents were implanted into the common iliac arteries of minipigs, which were divided into 10 groups (six in each group) according to euthanasia time (6 hours, and 1, 3, 7, 14, 28, 56, 84, 168, and 336 days). After the samples were harvested, haematoxylin and eosin staining, immunohistochemical staining, Western blotting, and Picrosirius red staining were performed for all groups.

RESULTS

ISR occurred in all six minipigs in the 56 day group (percentage diameter stenosis range 71.6%-79.2%, mean ± standard deviation 75.6% ± 2.5%). The percentage diameter stenosis decreased to 38.3% ± 2.7% at 336 days (p < .001). Immunohistochemical staining showed that MMP-2 and MMP-9 were strongly stained near the internal elastic lamina or in the damaged parts of the intima, around the struts and neointimal lumen surface in the ISR process. The expression of MMP-2 and MMP-9 at 56 days was significantly lower compared with their peaks (seven days and one day [p < .001; p = .002], respectively). At 56 days, the collagen content reached its maximum (mean integrated optical density range 0.73-0.92, mean ± standard deviation 0.82 ± 0.09). From the 14 day group to the 336 day group, mature collagen in neointima was correlated negatively with MMP-2 (γ(36) = -0.816; p < .001) and MMP-9 expression (γ(36) = -0.853; p < .001). During the neointimal regression period, new collagen in neointima was positively correlated with MMP-2 (γ(24) = 0.683; p < .001) and MMP-9 (γ(24) = 0.873; p < .001).

CONCLUSION

This study has demonstrated the spatial distribution of and dynamic changes in MMP-2, MMP-9, and collagen in ISR by simulating the process of neointima from generation to regression after stent implantation. When ISR occurred, MMP-2 and MMP-9 expression decreased and collagen content reached its maximum, which might contribute to ISR.

Chemokine-like factor 1 (CKLF1) aggravates neointimal hyperplasia through activating the NF-κB /VCAM-1 pathway

Neointimal hyperplasia (NIH) is a complicated inflammatory process contributing to vascular restenosis. The present study aimed to explore whether chemokine-like factor 1 (CKLF1) aggravates NIH via the nuclear factor-kappa B (NF-κB)/vascular cell adhesion molecule-1 (VCAM-1) pathway. We found the expression of CKLF1 and VCAM-1 significantly increased in human carotid plaques compared to the control. In vivo, CKLF1 overexpression induced a thicker neointimal formation and VCAM-1 expression was correspondingly upregulated. In vitro, CKLF1 activated NF-κB and induced VCAM-1 upregulation in human aortic smooth muscle cells (HASMCs). Functional experiments demonstrated that CKLF1 promoted monocyte adhesion and HASMC migration via VCAM-1. These results suggest CKLF1 accelerates NIH by promoting monocyte adhesion and HASMC migration via the NF-κB/VCAM-1 pathway. Our findings contribute to a better understanding of the mechanisms underlying the causality of CKLF1 on NIH and could prove beneficial in designing therapeutic modalities with a focus on CKLF1.

Impact of Elective, Uncomplicated Target Lesion Revascularization on Cardiac Mortality After Elective Percutaneous Coronary Intervention of Unprotected Left Main Coronary Artery Disease

This study sought to investigate the impact of elective, uncomplicated target lesion revascularization (TLR) on long-term cardiac mortality after percutaneous coronary intervention (PCI) of unprotected left main coronary artery (ULMCA) disease. Consecutive patients undergoing PCI for ULMCA disease between January 2003 and December 2015 in 1 interventional center in Northern Italy were included. Patients presenting with cardiogenic shock, ST-segment elevation myocardial infarction (MI), as well as those undergoing urgent or complicated TLR were excluded. The primary endpoint of the study was cardiac mortality. Among the 418 patients fulfilling the study criteria, 79 (18.46%) underwent elective, uncomplicated TLR. After a median follow-up of 5.5 years, there were 23 cardiac deaths among patients undergoing elective, uncomplicated TLR versus 50 in patients not undergoing TLR. After adjusting for possible confounders, TLR was an independent predictor of cardiac mortality (Hazard ratio [HZ] = 1.92, 95% confidence interval [CI]: 1.05 to 3.49; p = 0.03). Patients undergoing TLR had also significantly higher rates of the composite of cardiac death, MI and stroke compared with the no TLR group (adjusted HR = 1.76, 95% CI 1.14 to 2.72). In conclusion, elective, uncomplicated TLR after PCI of ULMCA disease is associated with increased risk of long-term cardiac mortality. Reducing the risk of TLR after PCI of ULMCA disease may potentially improve the survival of these patients.

Impact of Intravascular Brachytherapy on Patient-Reported Outcomes in Patients with Coronary Artery Disease

BACKGROUND

Intravascular brachytherapy (VBT) is an established treatment for the management of in-stent restenosis (ISR). However, whether VBT is associated with improved patient reported outcomes unknown.

METHODS

We evaluated 51 consecutive patients undergoing VBT in one or more coronary arteries from January 2018 to September 2019. Data on baseline characteristics, procedural outcomes and adverse events were obtained. All patients completed the Seattle Angina Questionnaire - 7 (SAQ-7) form before and after VBT at 1 month and 6 months.

RESULTS

The mean age was 69 ± 9 years and 29 (57%) of patients were males. Procedural success was 94.1%. The mean summary SAQ-7 score improved significantly (53.2 ± 21 vs. 83 ± 19, p < .001) at 30-days. The median Quality of Life (QoL) component of SAQ-7 score was 31.3 (Interquartile Range [IQR]: 18.8, 62.5) and improved to 82.5 (IQR: 62.5, 100), p < .001 at 30 days and 87.5 [IQR: 75, 100), p < .001 at last follow up. Likewise, the median angina frequency component of the SQL-7 score pre-VBT was 55 (IQR: 45, 80) and improved significantly to 90 (IQR: 60, 100) at 30-days, p < .001 and 100 [IQR: 68.8, 100], p = .02 at last follow up. Lastly, the median activity component of the SAQ-7 score improved from 83.3 (IQR: 60-100) to 100 (IQR: 83, 100), p = .01 at 30-days. Thus, results were evident as early as 1 month and sustained at median follow up of 17 months.

CONCLUSION

VBT is associated with improvement in patient reported outcome measures at short term and long term follow up.

Long-Term Efficacy of Biodegradable Metal-Polymer Composite Stents After the First and the Second Implantations into Porcine Coronary Arteries

A biodegradable coronary stent is expected to eliminate the adverse events of an otherwise eternally implanting material after vessel remodeling. Both biocorrodible metals and biodegradable polymers have been tried as the matrix of the new-generation stent. Herein, we utilized a metal-polymer composite material to combine the advantages of the high mechanical strength of metals and the adjustable degradation rate of polymers to prepare the biodegradable stent. After coating polylactide (PLA) on the surface of iron, the degradation of iron was accelerated significantly owing to the decrease of local pH resulting from the hydrolysis of PLA, etc. We implanted the metal-polymer composite stent (MPS) into the porcine artery and examined its degradation in vivo, with the corresponding metal-based stent (MBS) as a control. Microcomputed tomography (micro-CT), coronary angiography (CA), and optical coherence tomography (OCT) were performed to observe the stents and vessels during the animal experiments. The MPS exhibited faster degradation than MBS, and the inflammatory response of MPS was acceptable 12 months after implantation. Additionally, we implanted another MPS after 1-year implantation of the first MPS to investigate the result of the MPS in the second implantation. The feasibility of the biodegradable MPS in second implantation in mammals was also confirmed.

Computational analysis of Nitinol stent-graft for endovascular aortic repair (EVAR) of abdominal aortic aneurysm (AAA): Crimping, sealing and fluid-structure interaction (FSI)

OBJECTIVES

We evaluate the crimping strain, sealing stress and contact forces on a Nitinol stent deployed in the aorta during endovascular aortic (or aneurysm) repair (EVAR) procedures. Nitinol shape memory effect (SME) is used. We also study the fluid-structure interaction (FSI) of the blood flow on the stented aorta.

METHODS

We employ Solidworks to generate a closed-cell honeycomb stent structure used to treat abdominal aortic aneurysm (AAA). We use the commercial Abaqus/Simulia finite element (FEM) simulation package to study the displacements and stresses experienced by the stent during the crimping phase and deployment into the aortic segment. The Nitinol stent is covered with Dacron, a popular graft material. We implement our own user-material (UMAT) subroutines to model the shape memory effect (SME) of Nitinol. The effect of the stent geometry is analyzed. We use the FSI analysis in Abaqus/Simulia to understand the effect of hemodynamic loading on the stent.

RESULTS

Results indicate that the crimping strain increases as the stent strut spacing increases. This is also the case for the radius of curvature. Maximum strains developed on the stent during crimping are in the order of 10%. Stresses exerted by the stent needed to completely seal the aorta are found to be below the yield stress values of Nitinol (700 MPa). Wall shear stresses (WSS) on the stented aorta are close to WSS obtained on the aorta alone.

CONCLUSION

Using Nitinol's thermo-reactivity property as opposed to its superelasticity causes the stent-graft to deploy more gently.

Novel Zinc / Tungsten Carbide Nanocomposite as Bioabsorbable Implant

There is a lack of bioabsorbable materials with adequate mechanical strength suitable for implant applications that provide temporary support while tissue integrity is restored, especially for pediatric applications. Bioabsorbable metals have emerged as an attractive choice due to their combination of strength, ductility, and biocompatibility in vivo. Zinc has shown great promise as a bioabsorbable metal, but the weak mechanical properties of pure zinc limit its application as an implant material. This study investigates zinc-tungsten carbide (Zn-WC) nanocomposite as a novel material for bioabsorbable metallic implants. Ultrasound-assisted powder compaction was used to fabricate Zn-WC nanocomposites. This study includes the material characterization of microstructure, microhardness, and degradability. Results showed that tungsten carbide nanoparticles enhanced the mechanical properties of Zn, and maintained the favorable corrosion rate of pure Zn. These results encourage further investigation of Zn-WC nanocomposites for biomedical applications with the ultimate goal of creating safe and efficacious bioabsorbable metallic implants for many clinical applications.

An application of RASER technique in the treatment of chronic total occlusion accompanied with stent fracture in right coronary artery: a case report

BACKGROUND

The interventional treatment of chronic total occlusion (CTO) with stent fracture as well as severe calcification was extremely difficult and no effective technique has been reported.

CASE PRESENTATION

A 50-year-old woman was hospitalized for angina, angiography revealed triple vessel disease, CTO accompanied with stent fracture in right coronary artery (RCA). Treatment using conventional coronary intervention was expected to be difficult. Therefore, we performed RASER technique, which was a combination of excimer laser coronary atherectomy (ELCA) with rotational atherectomy (RA), followed by the deployment of drug-eluting stents. Intravascular ultrasound (IVUS) revealed well attachment of the stents, the patient was discharged 3 days after the procedure and no recurrent chest discomfort was reported in a follow-up time of 10 months.

CONCLUSION

This case report provided a first report of RASER technique in the treatment of CTO with stent fracture and severe calcification.

Differential Phagocytosis-Based Photothermal Ablation of Inflammatory Macrophages in Atherosclerotic Disease

Inflammatory macrophage (Mφ)-mediated atherosclerosis is a leading cause of mortality and morbidity worldwide. Photothermal therapy (PTT) has been demonstrated as an efficient strategy in killing target cells, and its application in the treatment of inflammation in atherosclerosis is developing. However, the choice of nanomaterials, mechanisms, and side effects are seldom considered. In this study, semiconductor nanomaterials, that is, MoO₂ nanoclusters, were synthesized and used for the first time in PTT for inflammatory Mφ-mediated atherosclerosis. Based on cell differential phagocytosis, the optimum amount of MoO₂ and treatment time were selected to exert the maximum ablation effect on Mφ and minimal damage on endothelial cells without requiring additional target or selective groups. Moreover, MoO₂-based PTT shows an excellent therapeutic effect on atherosclerosis by eliminating Mφ in animal models, with no significant side effects observed. This study explores a new method of nanotechnology and pharmaceutical development by using and optimizing cost-effective metal oxide nanostructures in the treatment of atherosclerosis and motivates further research on minimizing the side effects of related materials.

Experimentally validated simulation of coronary stents considering different dogboning ratios and asymmetric stent positioning

In-stent restenosis remains a major problem of arteriosclerosis treatment by stenting. Expansion-optimized stents could reduce this problem. With numerical simulations, stent designs/ expansion behaviours can be effectively analyzed. For reasons of efficiency, simplified models of balloon-expandable stents are often used, but their accuracy must be challenged due to insufficient experimental validation. In this work, a realistic stent life-cycle simulation has been performed including balloon folding, stent crimping and free expansion of the balloon-stent-system. The successful simulation and validation of two stent designs with homogenous and heterogeneous stent stiffness and an asymmetrically positioned stent on the balloon catheter confirm the universal applicability of the simulation approach. Dogboning ratio, as well as the final dimensions of the folded balloon, the crimped and expanded stent, correspond well to the experimental dimensions with only slight deviations. In contrast to the detailed stent life-cycle simulation, a displacement-controlled simulation can not predict the transient stent expansion, but is suitable to reproduce the final expanded stent shape and the associated stress states. The detailed stent life-cycle simulation is thus essential for stent expansion analysis/optimization, whereas for reasons of computational efficiency, the displacement-controlled approach can be considered in the context of pure stress analysis.

Angiography and Optical Coherence Tomography Assessment of the Drug-Coated Balloon ESSENTIAL for the Treatment of In-Stent Restenosis

OBJECTIVES

This study sought to assess the efficacy of the drug-coated balloon (DCB) ESSENTIAL for the treatment of in-stent restenosis (ISR).

BACKGROUND

DCBs have proven a valid therapeutic option for the management of ISR in several clinical trials, yet no class effect can be claimed. Accordingly, every new DCB model has to be individually evaluated through clinical studies.

METHODS

This is a prospective, multicenter study including consecutive patients undergoing percutaneous coronary intervention for ISR with the ESSENTIAL DCB. A 6-month quantitative coronary angiography (QCA)/optical coherence tomography (OCT) follow-up was scheduled. The primary endpoint was OCT-derived in-segment maximal area stenosis. Secondary endpoints included QCA-derived in-segment late lumen loss (LLL) and target lesion failure (TLF) rates at 6, 12, and 24 months. TLF was defined as the composite of cardiac death, target vessel myocardial infarction, and target lesion revascularization.

RESULTS

A total of 31 patients were successfully treated with DCB, with 67% of ISR corresponding to drug-eluting stents (DES). At 6 months, 26 patients underwent the scheduled angiographic follow-up. The mean value for in-segment maximal area stenosis was 51.4 ± 13% and the median value was 53% (IQR 46.4-59.5). In the DES-ISR subgroup, these parameters were 52.6 ± 10% and 55.2% (IQR 49.3-58.5), respectively. In-segment LLL was 0.25 ± 0.43 mm with only 2 (7.7%) patients showing binary restenosis (>50%). The incidence of TLF was 10% at 6 months, 13.3% at 12 months, and 13.3% at 24 months.

CONCLUSIONS

In this study, the ESSENTIAL DCB showed sustained efficacy in the prevention of recurrent restenosis after treatment of ISR.

SUMMARY

We sought to assess the efficacy of the drug-coated balloon ESSENTIAL for the treatment of in-stent restenosis through a prospective, multicenter study including QCA and OCT assessment at 6-month follow-up. The primary endpoint was in-segment maximal area stenosis. Among the 31 patients successfully treated with the ESSENTIAL DCB, an angiographic follow-up was conducted in 26. Mean in-segment maximal area stenosis was 51.4 ± 13% and the median value was 53% (IQR 46.4-59.5). In the DES-ISR subgroup, corresponding values were 52.6 ± 10% and 55.2% (IQR 49.3-58.5), respectively. The observed in-segment LLL was 0.25 ± 0.43 mm and binary restenosis rate was 7.7%. TLF was 10% at 6 months and 13.3% at 12 and 24 months.

Restenosis of Drug-Eluting Stents

Despite on-going evolution and iteration of drug-eluting stent (DES) technology, the prevalence of in-stent restenosis (ISR) remains relatively unchanged, encompassing ≈10% of percutaneous coronary interventions. The mechanism of ISR is multifactorial, including biological, mechanical, patient, and operator-related factors. The main mechanical contributors are stent underexpansion or fracture, while biological factors include local inflammation leading to aggressive neointimal proliferation and late neoatherosclerosis. Intracoronary imaging is critical to identify the mechanism of ISR and tailor therapy accordingly. The presentation of DES-ISR is not benign and is challenging for optimal treatment. Among the proposed treatment modalities are scoring and high-pressure balloons, percutaneous coronary intervention with additional DES, atheroablative therapies by laser or mechanical atherectomy, drug-coated balloons, vascular brachytherapy, and surgical revascularization. We propose a new classification for ISR that differentiates among mechanical, biological, and mixed etiologies. Stratifying ISR by mechanism guides individualized treatment of DES-ISR to improve clinical outcomes. An algorithmic approach, guided by intracoronary imaging, for the treatment of DES-ISR, is recommended based on the specific cause of restenosis.

The effect of the debulking by excimer laser coronary angioplasty on long-term outcome compared with drug-coating balloon: insights from optical frequency domain imaging analysis

This study evaluated the 1-year efficacy of excimer laser coronary angioplasty (ELCA) before drug-coated balloon (DCB) dilatation for the treatment of in-stent restenosis (ISR). Forty consecutive patients with ISR were treated by DCB with or without the use of ELCA (ELCA plus DCB, N = 20; DCB alone, N = 20). Debulking efficiency (DE) value was defined as the neointima area on optical frequency domain imaging (OFDI) debulked by ELCA. The patients in the ELCA plus DCB group were divided into two groups (greater DE (GDE), N = 10; smaller DE (SDE), N = 10) based on the median value of DE. Thereafter, the ISR segment was prepared with a scoring balloon, followed by DCB. At follow-up, binary restenosis and target lesion revascularization (TLR) were evaluated. There were no significant differences in baseline characteristics such as age, comorbidity, and ISR type. Overall, the incidence of neoatherosclerosis in the ISR segment was 17.5%. Post-PCI, acute gain of minimum lumen diameter on quantitative coronary angiography and of minimum lumen area on OFDI was numerically higher in the GDE than in the SDE and the DCB alone group. At follow-up, the occurrences of binary restenosis and TLR in the ELCA plus DCB group were 20.0% and 10.0%; these values in the DCB alone group were 20.0% and 20.0%, respectively. Two patients from the SDE and none from the GDE developed TLR. DCB alone treatment was inferior to ELCA plus DCB treatment. However, greater ELCA debulking might be required to obtain optimal outcomes.

Three-dimensional evaluation of the spatial morphology of stented coronary artery segments in relation to restenosis

To investigate the correlations between the three-dimensional (3D) parameters of target coronary artery segments and restenosis after stent implantation. Sixty-four patients after single, cobalt chromium platform stent (27 BM stents and 37 DES) implantation were investigated retrospectively 12 ± 6 months after the index procedure. 3D coronary artery reconstruction was performed before and after the stent implantation using appropriate projections by a dedicated reconstruction software. The curve of the target segment was characterized by the ratio of the vessel length measured at midline (arc: A) and the distance between the edge points of the stent (chord: C): A/C ratio (ACr). Age, diabetes and hyperlipidaemia were taken into account for the statistical evaluation. 22 patients were diagnosed with ISR, while 42 patients without any restenosis served as controls. The two groups did not differ regarding major cardiovascular risk factors, proportion of the treated vessels or the type of stents. Higher initial ACr values were associated with greater straightening of the vessel curvature in all groups (p < 0.001). Significant negative correlations were found in cases of proximal or distal edge bending angles (p < 0.001). Pre-stent edge bending angles < 7° often showed an increase after the stent implantation, while in case of higher initial values, the bending angles generally decreased. Using multivariate logistic regression modelling we found that the pre-stent ACr was an independent predictor of in-stent restenosis (odds ratio for 1% increase of the ACr: 1.08; p = 0.012). Changes of angles at the stent edges following stent implantation correlate with the initial local bending angles. The ACr predispose to chronic shear stress in the vessel wall, which may contribute to the pathological intimal proliferation.

Contemporary Management of Stent Failure: Part One

The occurrence of in-stent restenosis (ISR) still remains a daunting challenge in the current era, despite advancements in coronary intervention technology. The authors explore the underlying pathophysiology and mechanisms behind ISR, and describe how the use of different diagnostic tools helps to best elucidate these. They propose a simplistic algorithm to manage ISR, including a focus on how treatment strategies should be selected and a description of the contemporary technologies available. This article aims to provide a comprehensive outline of ISR that can be translated into evidence-based routine clinical practice, with the aim of providing the best outcomes for patients.

Diagnostic accuracy of dual-source and 320-row computed tomography angiography in detecting coronary in-stent restenosis: a systematic review and meta-analysis

BACKGROUND

Dual-source and 320-row computed tomography angiography (CTA) are increasingly used in diagnosing coronary in-stent restenosis (CISR).

PURPOSE

We sought to perform this meta-analysis to evaluate the diagnostic accuracy of dual-source computed tomography angiography (DSCTA) and 320-row CTA in detecting CISR when compared to invasive coronary angiography.

MATERIAL AND METHODS

Five scientific databases (PubMed, Embase, Scopus, The Cochrane Library, and Web of Science) were searched for research studies in which DSCTA and/or 320-row CTA were used as diagnostic tools for CISR, as recently as October 2017. Study inclusion, data extraction, systematic review, pooled meta-analysis, and subgroup analysis were conducted by two researchers independently.

RESULTS

Thirteen studies with 1384 assessable stents on DSCTA and five studies including 622 assessable stents on 320-row CTA were finally included. The sensitivity, specificity, and area under the curve (AUC) of DSCTA in diagnosing CISR were 0.92 (0.87-0.96), 0.91 (0.87-0.94), and 0.97 (0.95-0.98), respectively, and they were 0.91 (0.82-0.96), 0.95 (0.88-0.98), and 0.96 (0.94-0.97) for 320-row CTA. Subgroup analysis result suggested that DSTCA performed significantly better in CISR detection when the stent diameter was ≥ 3 mm compared to stent diameter < 3 mm: 0.98 (0.97-0.99) vs. 0.82 (0.79-0.86) with P < 0.05.

CONCLUSION

Our meta-analysis indicated both DSCTA and 320-row CTA had high diagnostic accuracy in detecting CISR and may serve as alternatives for further patient evaluation with CISR, especially for stent diameters ≥ 3 mm.