Current understanding of coronary in-stent restenosis. Pathophysiology, clinical presentation, diagnostic work-up, and management

Risk factors for in-stent restenosis in maintenance hemodialysis patients with central venous occlusive disease and biomechanical assessment of stents

OBJECTIVES

To investigate the risk factors and biomechanical mechanisms of in-stent restenosis (ISR) in central venous occlusive disease (CVOD).

PATIENTS AND METHODS

This retrospective study consecutively included 77 maintenance hemodialysis (MHD) patients with CVOD who received the first percutaneous transluminal angioplasty with stenting (PTS) due to symptomatic CVOD in a tertiary hospital. The mean age was 59.7 ± 14.0 years, and 51.9% of patients were male. The clinical characteristics, occurrence of ISR and patency rates were recorded. Finite element method was applied to assess the biomechanical properties of stents.

RESULTS

Among 77 patients with a mean CVS score of 8.0 ± 2.8, 20.8%, 62.3%, and 16.9% of patients had the main vein of CVOD in the subclavian vein, brachiocephalic vein, and superior vena cava, respectively. A total of 72 (93.5%) patients received successful PTS treatment, for which the stents implanted were mainly Fluency covered stent (48.6%) and SMART bare stent (31.9%). During 15 (10-24)-months of follow-up, ISR occurred in 36.1% of the 72 patients. The primary and assisted primary patency rates at 6, 12, and 18 months were 78%, 56%, 42% and 95%, 90%, 87%, respectively. A prolonged dialysis vintage was an independent risk factor for ISR, yet the stent type or the main vein location was not correlated with ISR. Among three laser-engraving stents, the SMART stent was the best in terms of flexibility, stress, and strain on stents but worst in stress or strain on vessels. The Luminexx stent was the best in radial force and worst in stress or strain on stents. The Vici stent was the best in stress and strain on vessels and worst in radial force and flexibility.

CONCLUSIONS

An unsatisfactory comprehensive biomechanical performance from configurations rooted in existing stents may account for the high incidence of ISR in CVOD.

Biomarkers Associated with Immune Checkpoint, N6-Methyladenosine, and Ferroptosis in Patients with Restenosis

Purpose

This study aimed to identify potential diagnostic markers of restenosis after stent implantation and to determine their association with immune checkpoint, ferroptosis, and N6-methyladenosine (m6A).

Patients and methods

Microarray data were downloaded from the National Center for Biotechnology Information (NCBI: GSE46560 and GSE48060 datasets) to identify differentially expressed genes (DEGs) between in-stent restenosis and no-restenosis samples. We then conducted systematic functional enrichment analyses of the DEGs based on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), and further predicted the interactions of different proteins using the Search Tool for the Retrieval of Interacting Genes (STRING). We used the MCC and MCODE algorithms in the cytoHubba plug-in to screen three key genes in the network, and employed receiver operating characteristic (ROC) curves to determine their diagnostic significance using a multiscale curvature classification algorithm. Next, we investigated the relationships between these target genes, immune checkpoint, ferroptosis, and m6A. Finally, quantitative real-time polymerase chain reaction (qRT-PCR) was used to verify the above results.

Results

We identified 62 upregulated genes and 243 downregulated genes. Based on GO, KEGG, and screening results, EEF1D, RPL36, and RPSA are promising genes for predicting restenosis. In addition, the methylation of YTHDF2, the ferroptosis-related gene GLS2, and the immune checkpoint-related gene CTLA4 were observed to be associated with restenosis. The qRT-PCR test confirmed that RPSA and RPL36 are useful diagnostic markers of the restenosis that can provide new insights for future studies on its occurrence and molecular mechanisms.

Conclusion

We found that RPSA and RPL36, as useful diagnostic markers of restenosis, can provide new insights for future studies on its occurrence and molecular mechanisms.

Electrical Conductance Device for Stent Sizing

The minimum stent area (MSA) has been clinically established as a significant predictor of restenosis, thrombosis, and ischemia using intra-vascular ultrasound (IVUS). Unfortunately, IVUS measurements are far from routine because of significant cost of IVUS, the training required, the subjectivity of image interpretation and the time added to the procedure. The objective of this study is to verify the accuracy of a conductance catheter for stent sizing. Here, we introduce an easy and entirely objective device and method for real time determination of MSA. A 10 kHz, 35 μA rms current is passed through the external electrodes of an intravascular catheter while the conductance is measured across a separate set of electrodes. Both phantom and ex vivo validations of metal stent sizing in five porcine carotid arteries were confirmed. The accuracy of the measurements were found to be excellent in phantoms (root mean square, rms, of 3.4% of actual value) and in ex-vivo vessels (rms = 3.2% of measured value). An offset of conductance occurs when a conductive metal stent (e.g., bare metal stent) is deployed in the vessel, while the slope remains the same. This offset is absent in the case of drug eluting stent where the metal is coated (i.e., insulated) or non-metal bioresorbable stent. The present device makes easy, accurate and reproducible measurements of the size of stented blood vessels within 3.2% rms error. This device provides an alternative method to sizing of stent (i.e., MSA) in real-time without subjective interpretation and with less cost than IVUS.

Endovascular stent-induced alterations in host artery mechanical environments and their roles in stent restenosis and late thrombosis

Cardiovascular stent restenosis remains a major challenge in interventional treatment of cardiovascular occlusive disease. Although the changes in arterial mechanical environment due to stent implantation are the main causes of the initiation of restenosis and thrombosis, the mechanisms that cause this initiation are still not fully understood. In this article, we reviewed the studies on the issue of stent-induced alterations in arterial mechanical environment and discussed their roles in stent restenosis and late thrombosis from three aspects: (i) the interaction of the stent with host blood vessel, involve the response of vascular wall, the mechanism of mechanical signal transmission, the process of re-endothelialization and late thrombosis; (ii) the changes of hemodynamics in the lumen of the vascular segment and (iii) the changes of mechanical microenvironment within the vascular segment wall due to stent implantation. This review has summarized and analyzed current work in order to better solve the two main problems after stent implantation, namely in stent restenosis and late thrombosis, meanwhile propose the deficiencies of current work for future reference.

Monocyte to HDL ratio in prediction of BMS restenosis in subjects with stable and unstable angina pectoris

AIM

This study aims to assess the predictive role of the preprocedural circulating monocyte to high-density lipoprotein (HDL) cholesterol ratio (MHR) on the occurrence of stent restenosis (SR) in patients with stable and unstable angina pectoris undergoing successful bare-metal stenting (BMS).

PATIENTS & METHODS

Between February 2008 and June 2014, a total of 831 patients with stable and unstable angina pectoris who underwent successful BMS were retrospectively analyzed. Demographic and clinical characteristics of the patients were recorded. Left ventricular ejection fraction and laboratory data were also noted.

RESULTS

In the receiver operating characteristics curve analysis, MHR >14 had 71% sensitivity and 69% specificity in predicting SR.

CONCLUSION

Our study results show that preprocedural MHR is an independent predictor of SR in this patient population.

The Relationship Between Lymphocyte-to-Monocyte Ratio and Bare-Metal Stent In-Stent Restenosis in Patients With Stable Coronary Artery Disease

In-stent restenosis (ISR) is a common clinical problem in patients with coronary artery disease treated with percutaneous coronary intervention. Inflammatory process plays a pivotal role in the development of ISR. Both lymphocytes and monocytes are associated with inflammatory status. Recently, it has been shown that the lymphocyte-to-monocyte ratio (LMR) is a novel inflammatory marker. We aimed to investigate the association of serum LMR levels and ISR in patients undergoing bare-metal stent (BMS) implantation. The study included 273 patients (aged 61 ± 11 years, 66.5% men) with a history of BMS implantation and a further control coronary angiography due to stable angina pectoris. Patients were divided into 2 groups: patients with and without ISR. The LMR levels were significantly lower in patients with ISR than in those without ISR (2.50 ± 0.95 vs 3.87 ± 1.51, respectively, P < .001). On multivariate logistic regression analysis, the LMR was independently associated with ISR (odds ratio [OR]: 0.310, 95% confidence interval: 0.166-0.579, P < .001) together with high-sensitivity C-reactive protein (OR: 1.244, P = .008), reason for stent implantation (OR: 6.566, P = .003), stent diameter (OR: 0.015, P < .001), and stent length (OR: 1.137, P = .007). In conclusion, LMR levels are inversely related to ISR in patients treated with BMS implantation.

Costs and clinical outcomes for non-invasive versus invasive diagnostic approaches to patients with suspected in-stent restenosis

This study compared costs and clinical outcomes of invasive versus non-invasive diagnostic evaluations for patients with suspected in-stent restenosis (ISR) after percutaneous coronary intervention. We developed a decision model to compare 2 year diagnosis-related costs for patients who presented with suspected ISR and were evaluated by: (1) invasive coronary angiography (ICA); (2) non-invasive stress testing strategy of myocardial perfusion imaging (MPI) with referral to ICA based on MPI; (3) coronary CT angiography-based testing strategy with referral to ICA based on CCTA. Costs were modeled from the payer's perspective using 2014 Medicare rates. 56 % of patients underwent follow-up diagnostic testing over 2 years. Compared to ICA, MPI (98.6 %) and CCTA (98.1 %) exhibited lower rates of correct diagnoses. Non-invasive strategies were associated with reduced referrals to ICA and costs compared to an ICA-based strategy, with diagnostic costs lower for CCTA than MPI. Overall 2-year costs were highest for ICA for both metallic as well as BVS stents ($1656 and $1656, respectively) when compared to MPI ($1444 and $1411) and CCTA. CCTA costs differed based upon stent size and type, and were highest for metallic stents >3.0 mm followed by metallic stents <3.0 mm, BVS < 3.0 mm and BVS > 3.0 mm ($1466 vs. $1242 vs. $855 vs. $490, respectively). MPI for suspected ISR results in lower costs and rates of complications than invasive strategies using ICA while maintaining high diagnostic performance. Depending upon stent size and type, CCTA results in lower costs than MPI.

Preprocedural Albumin Levels and Risk of In-Stent Restenosis After Coronary Stenting With Bare-Metal Stent

In-stent restenosis (ISR) remains a significant clinical problem in patients with coronary artery disease treated with percutaneous coronary intervention. Decreased serum albumin (SA) level is related to an increased risk of cardiovascular events. The aim of the present study was to assess whether SA levels at admission are an independent predictor of ISR in patients undergoing bare-metal stent (BMS) implantation. A total of 341 patients (aged 61 ± 11, 65.4% men) with a history of BMS implantation and a further control coronary angiography due to stable angina pectoris (SAP) were included. The study population was classified into 2 groups: patients with and without ISR. The ISR was observed in 140 (41.1%) patients. We found significantly lower SA levels in patients who developed ISR than in those who did not (3.69 ± 0.41 vs 4.07 ± 0.35 mg/dL,P< .001). Multivariate analysis revealed that SA level (odds ratio 0.109, 95% confidence interval 0.017-0.700,P= .020), stent diameter, reason for stent implantation, and body mass index were independent risk factors for the development of ISR. The SA level at admission is inversely associated with ISR in patients with SAP.

In vitro photodynamic therapy with chlorin e6 leads to apoptosis of human vascular smooth muscle cells

Percutaneous coronary intervention has become the most common and widely implemented method of heart revascularization. However, the development of restenosis remains the major limitation of this method. Photodynamic therapy (PDT) recently emerged as a new and promising method for the prevention of arterial restenosis. Here the efficacy of chlorin e6 in PDT was investigated in vitro using human vascular smooth muscle cells (TG/HA-VSMCs) as one of the cell types crucial in the development of restenosis. PDT-induced cell death was studied on many levels,including annexin V staining, measurement of the generation reactive oxygen species (ROS) and caspase-3 activity,and assessment of changes in mitochondrial membrane potential and fragmentation of DNA. Photosensitization of TG/HA-VSMCs with a 170 lM of chlorin e6 and subsequent illumination with the light of a 672-nm diode laser(2 J/cm2) resulted in the generation of ROS, a decrease in cell membrane polarization, caspase-3 activation, as well as DNA fragmentation. Interestingly, the latter two apoptotic events could not be observed in photosensitized and illuminated NIH3T3 fibroblasts, suggesting different outcomes of the model of PDT in various types of cells. The results obtained with human VSMCs show that chlorin e6 may be useful in the PDT of aerial restenosis, but its efficacy still needs to be established in an animal model.

Leukemia inhibitory factor is upregulated in coronary arteries of Ossabaw miniature swine after stent placement

Leukemia inhibitory factor (LIF), an IL-6 class cytokine, is reported to be antiatherosclerotic. Thus, we hypothesized that LIF expression might be altered during in-stent neointimal hyperplasia. Ossabaw miniature swine, a unique large-animal model of metabolic syndrome and cardiovascular disease, were used for these studies. Bare-metal stents were deployed in the left anterior descending and left circumflex coronary arteries. Stents were expanded to either 1.0 x luminal diameter (in accordance with current clinical practice) or 1.3 x (overexpansion). The development of in-stent neointimal hyperplasia was assessed 28-day postimplantation using intravascular ultrasound. The atherosclerotic coverage of the vessel wall was approximately five-fold higher in 1.0 x stents and approximately nine-fold higher in 1.3 x stents 4 weeks after deployment, compared with the same segments before stenting. LIF mRNA was elevated approximately 11-fold in stented segments, relative to unstented epicardial coronary arteries. LIF expression and the intima : media ratio were strongly correlated in 1.0 x stented vessels. Further studies to investigate the nature of the association between LIF and neointimal hyperplasia revealed that vascular smooth muscle cell proliferation was inhibited by LIF treatment in an in-vitro model of atherosclerosis (coronary artery organ culture). These novel and clinically relevant studies show that elevated LIF gene expression is predictive for in-stent neointimal hyperplasia, and suggest that LIF upregulation may be a compensatory mechanism in this setting.

Late Restenosis Following Placement of a Sirolimus Eluting Stent for In-Stent Restenosis

Drug eluting stents (DES) are rapidly replacing intravascular brachytherapy for the treatment of bare metal in-stent restenosis (ISR). To date, there are no long-term follow up data supporting this practise. We report symptomatic repeat in-stent restenosis occurring 27 months after sirolimus eluting stent deployment for de novo in-stent restenosis. This case suggests that in a subgroup of patients with ISR, as with brachytherapy, the drug eluting stent may be simply delaying rather than inhibiting the restenotic process.

Opposite effects of vascular irradiation on inflammatory response and apoptosis induction in the vessel wall layers via the peroxynitrite-poly(ADP-ribose) polymerase pathway

PURPOSE

We investigated in a surgical rat model of vascular injury the potential role of the peroxynitrite - poly(ADPribose) polymerase (PARP) pathway in inflammatory response and apoptosis induction after vascular gamma irradiation.

METHODS

Male Sprague-Dawley rats underwent left carotid endarterectomy with removal of intima: control (n = 10) and were irradiated with 15 Gray (n = 13) or 20 Gray (n = 10) postoperatively and compared with sham-operated rats (n = 10). Additional animals were solely irradiated with 15 Gy (n = 10) and with 20 Gy (n = 10) to distinguish between primary effects of vascular injury and secondary effects due to irradiation.

RESULTS

After 21 days, neointima formation was significantly suppressed after irradiation (control: 0.07 mm(2) +/- 0.04 mm(2), 15 Gy: 0.003 mm(2) +/- 0.004 mm(2), 20 Gy: 0.001 mm(2) +/- 0.0006 mm(2), P< 0.0001). However, a significant inflammation of the vessel wall with focal wall necrosis was detected (control: 0.2 +/- 0.15, 15 Gy: 0.82 +/- 1.2, 20 Gy: 1.25 +/- 0.86, P= 0.003). Immunohistochemistry showed significant staining for nitrotyrosine, poly(ADP-ribose) and nuclear translocation of apoptosis-inducing factor in the neointima of the control group. In the irradiated groups these stainings were significantly higher in the media and adventitia compared to the non-irradiated groups.

CONCLUSION

Activation of the peroxynitrite-PARP pathway was demonstrated during neointima proliferation in a rat model of surgical vascular injury. Vascular irradiation suppressed neointima formation, but induced significant activation of the peroxynitrite - PARP pathway in the outer vessel wall layers concomitant to inflammation and focal wall necrosis. This may contribute to adverse effects of vascular irradiation such as fibrosis and constrictive remodeling.

Study of the effectiveness of musical stimulation during intracardiac catheterization

BACKGROUND

Intracardiac catheterization is a routine physical examination. Due to psychological strains, several psychosocial interventions, including music therapy, have been proposed. The aim of the present study was to examine whether the preventive or adjuvant use of music therapy results in a reduction in both subjective and objective anxiety and thus leads to a reduction in sedative medication. METHODS OF ASSESSMENT: N=83 patients (48 male, 35 female, 66+/-11 yrs) waiting for scheduled cardiac catheterization were randomly allocated to one of three groups: control group (standard care), exposure group (music stimulation during the procedure), or coaching group (additional music therapeutic coaching). Target variables were subjective anxiety and physiological parameters.

RESULTS

Music intervention did effectively reduce subjective anxiety (STAI-S reduction pre-post: exposure 11 pt, coaching: 4 pt, control: 6 pt; p=0.033). Physiological values and medication did not differ between groups.

CONCLUSION

The use of music stimulation during the catheterization has a relaxing and calming effect on patients. It seems to be especially beneficial in a subgroup of patients with higher-than-average psychological strains.