Inflammatory markers and plaque morphology: an optical coherence tomography study

Cigarette Smoking and Atherosclerotic Cardiovascular Disease

The detrimental effects of cigarette smoking on cardiovascular health, particularly atherosclerosis and thrombosis, are well established, and more detailed mechanisms continue to emerge. As the fundamental pathophysiology of the adverse effects of smoking, endothelial dysfunction, inflammation, and thrombosis are considered to be particularly important. Cigarette smoke induces endothelial dysfunction, leading to impaired vascular dilation and hemostasis regulation. Factors contributing to endothelial dysfunction include reduced bioavailability of nitric oxide, increased levels of superoxide anion, and endothelin release. Chronic inflammation of the vascular wall is a central pathogenesis of smoking-induced atherosclerosis. Smoking systemically elevates inflammatory markers and induces the expression of adhesion molecules and cytokines in various tissues. Pattern recognition receptors and damage-associated molecular patterns play crucial roles in the mechanism underlying smoking-induced inflammation. Smoking-induced DNA damage and activation of innate immunity, such as the NLRP3 inflammasome, cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway, and Toll-like receptor 9, are shown to amplify inflammatory cytokine expression. Cigarette smoke-induced oxidative stress and inflammation influence platelet adhesion, aggregation, and coagulation via adhesion molecule upregulation. Furthermore, it affects the coagulation cascade and fibrinolysis balance, causing thrombus formation. Matrix metalloproteinases contribute to plaque vulnerability and atherothrombotic events. The impact of smoking on inflammatory cells and adhesion molecules further intensifies the risk of atherothrombosis. Collectively, exposure to cigarette smoke exerts profound effects on endothelial function, inflammation, and thrombosis, contributing to the development and progression of atherosclerosis and atherothrombotic cardiovascular diseases. Understanding these intricate mechanisms highlights the urgent need for smoking cessation to protect cardiovascular health. This comprehensive review investigates the multifaceted mechanisms through which smoking contributes to these life-threatening conditions.

Pathophysiology of Acute Coronary Syndromes-Diagnostic and Treatment Considerations

Coronary artery disease and acute coronary syndromes are accountable for significant morbidity and mortality, despite the preventive measures and technological advancements in their management. Thus, it is mandatory to further explore the pathophysiology in order to provide tailored and more effective therapies, since acute coronary syndrome pathogenesis is more varied than previously assumed. It consists of plaque rupture, plaque erosion, and calcified nodules. The advancement of vascular imaging tools has been critical in this regard, redefining the epidemiology of each mechanism. When it comes to acute coronary syndrome management, the presence of ruptured plaques almost always necessitates emergent reperfusion, whereas the presence of plaque erosions may indicate the possibility of conservative management with potent antiplatelet and anti-atherosclerotic medications. Calcified nodules, on the other hand, are an uncommon phenomenon that has largely gone unexplored in terms of the best management plan. Future studies should further establish the importance of detecting the underlying mechanism and the role of various treatment plans in each of these distinct entities.

The Impact of Cytokines in Coronary Atherosclerotic Plaque: Current Therapeutic Approaches

Coronary atherosclerosis is a chronic pathological process that involves inflammation together with endothelial dysfunction and lipoprotein dysregulation. Experimental studies during the past decades have established the role of inflammatory cytokines in coronary artery disease, namely interleukins (ILs), tumor necrosis factor (TNF)-α, interferon-γ, and chemokines. Moreover, their value as biomarkers in disease development and progression further enhance the validity of this interaction. Recently, cytokine-targeted treatment approaches have emerged as potential tools in the management of atherosclerotic disease. IL-1β, based on the results of the CANTOS trial, remains the most validated option in reducing the residual cardiovascular risk. Along the same line, colchicine was also proven efficacious in preventing major adverse cardiovascular events in large clinical trials of patients with acute and chronic coronary syndrome. Other commercially available agents targeting IL-6 (tocilizumab), TNF-α (etanercept, adalimumab, infliximab), or IL-1 receptor antagonist (anakinra) have mostly been assessed in the setting of other inflammatory diseases and further testing in atherosclerosis is required. In the future, potential targeting of the NLRP3 inflammasome, anti-inflammatory IL-10, or atherogenic chemokines could represent appealing options, provided that patient safety is proven to be of no concern.

Joint High Level of Oxidized Low-Density Lipoprotein and High-Sensitivity C-Reactive Protein are Associated With Recurrent Stroke and Poor Functional Outcome in Minor Stroke or Transient Ischemic Attack

Background

Oxidized low‐density lipoprotein (oxLDL) and hs‐CRP (high‐sensitivity C‐reactive protein) plays an important role in cardiovascular diseases though inflammation and oxidative stress, etc. However, evidence on their combined effects on stroke prognosis is still limited. We aimed to explore the joint association of oxLDL and hs‐CRP with outcomes of minor stroke or transient ischemic attack.

Methods and Results

A subgroup of 3019 patients from the CHANCE trial (Clopidogrel in High‐Risk Patients With Acute Nondisabling Cerebrovascular Events) were analyzed. Baseline oxLDL and hs‐CRP levels were measured. The primary outcome was any stroke within 90 days. The secondary outcomes included any stroke within 1 year, and ischemic stroke, combined vascular events, and poor functional outcomes (modified Rankin Scale 2–6 or 3–6) at 90 days and 1 year. Vascular events outcomes were analyzed with Cox proportional hazards and poor functional outcomes with logistic models. Elevated oxLDL (>28.81 μg/dL) and hs‐CRP (>4.20 mg/L) was observed in 624 (20.67%) of the 3019 patients. Patients with oxLDL >28.81 μg/dL and hs‐CRP >4.20 mg/L had a higher risk of recurrent stroke within 90 days (adjusted hazard ratio, 1.52; 95% CI, 1.17–1.97), compared with those with oxLDL ≤28.81 μg/dL and hs‐CRP ≤4.20 mg/L, after adjusting relevant confounding factors (P=0.002). Similar results were observed for secondary outcomes (P<0.05 for all).

Conclusions

In patients with minor stroke or transient ischemic attack, joint high levels of oxLDL and hs‐CRP was associated with increased risk of recurrent stroke, combined vascular events, and poor functional outcome.

Non-Invasive Modalities in the Assessment of Vulnerable Coronary Atherosclerotic Plaques

Coronary atherosclerosis is a complex, multistep process that may lead to critical complications upon progression, revolving around plaque disruption through either rupture or erosion. Several high-risk features are associated with plaque vulnerability and may add incremental prognostic information. Although invasive imaging modalities such as optical coherence tomography or intravascular ultrasound are considered to be the gold standard in the assessment of vulnerable coronary atherosclerotic plaques (VCAPs), contemporary evidence suggests a potential role for non-invasive methods in this context. Biomarkers associated with deleterious pathophysiologic pathways, including inflammation and extracellular matrix degradation, have been correlated with VCAP characteristics and adverse prognosis. However, coronary computed tomography (CT) angiography has been the most extensively investigated technique, significantly correlating with invasive method-derived VCAP features. The estimation of perivascular fat attenuation as well as radiomic-based approaches represent additional concepts that may add incremental information. Cardiac magnetic resonance imaging (MRI) has also been evaluated in clinical studies, with promising results through the various image sequences that have been tested. As far as nuclear cardiology is concerned, the implementation of positron emission tomography in the VCAP assessment currently faces several limitations with the myocardial uptake of the radiotracer in cases of fluorodeoxyglucose use, as well as with motion correction. Moreover, the search for the ideal radiotracer and the most adequate combination (CT or MRI) is still ongoing. With a look to the future, the possible combination of imaging and circulating inflammatory and extracellular matrix degradation biomarkers in diagnostic and prognostic algorithms may represent the essential next step for the assessment of high-risk individuals.

Trans-Myocardial Blood Interleukin-6 Levels Relate to Intracoronary Imaging-Defined Features of Plaque Vulnerability and Predict Procedure-Induced Myocardial Infarction

BACKGROUND

Intravascular imaging has defined various vulnerable plaque (VP) phenotypes that predict future clinical events. Atherosclerosis is an inflammatory process and inflammation, measured by systemic biomarkers can also predict events and anti-inflammatory therapy is beneficial. We were interested to assess the relationship between plaque phenotypes and key inflammatory biomarkers, measured close to the coronary.

METHODS

Ninety-two patients scheduled for elective percutaneous coronary intervention (PCI) underwent virtual histology intravascular ultrasound, optical coherence tomography, pressure wire and blood sampling from the guide catheter (GC), coronary sinus (CS) to determine trans-myocardial gradient (TMG = CS-GC) and from peripheral blood. Procedure related troponin release was assessed at 6-hours post-PCI from peripheral venous blood. Biomarker data were analysed and compared with coronary data.

RESULTS

Interleukin (IL)-6 was associated with increased levels of tumour necrosis factor (TNF)-α and C-reactive protein (CRP) and the pre-PCI IL-6 TMG correlated with plaque features of vulnerability: plaque burden - PB (r = 0.253, p = 0.04) and minimal lumen area - MLA (r = -0.438, p = 0.007), although no relationship existed for thin-capped fibroatheroma defined by either imaging modality. Peripheral IL-6 levels had no correlation with post PCI troponin, although the pre-PCI IL-6 TMG was related (r = 0.334, p = 0.006), as was PB (r = 0.27, p = 0.029).

CONCLUSION

IL-6 TMG pre-PCI correlates with plaque burden and MLA that have been shown to predict future clinical events and is correlated with post-PCI troponin release. These associations were not apparent from peripheral blood and suggest that local coronary biomarker signatures may help further define vulnerability and risk.

Predictors of Coronary Plaque Erosion in Current and Non-Current Smokers With ST-Segment Elevation Myocardial Infarction - An Optical Coherence Tomography Study

BACKGROUND

Smoking is an important risk factor of plaque erosion. This study aimed to investigate the predictors of plaque erosion in current and non-current smokers presenting with ST-segment elevation myocardial infarction (STEMI).Methods and Results:A total of 1,320 STEMI patients with culprit plaque rupture or plaque erosion detected by pre-intervention optical coherence tomography were divided into a current smoking group (n=715) and non-current smoking group (n=605). Plaque erosion accounted for 30.8% (220/715) of culprit lesions in the current smokers and 21.2% (128/605) in the non-current smokers. Multivariable analysis showed age <50 years, single-vessel disease and the absence of dyslipidemia were independently associated with plaque erosion rather than plaque rupture, regardless of smoking status. In current smokers, diabetes mellitus (odds ratio [OR]: 0.29; 95% confidence interval [CI]: 0.10-0.83; P=0.021) was negatively associated with plaque erosion as compared with plaque rupture. In non-current smokers, minimal lumen area (MLA, OR: 1.37; 95% CI: 1.16-1.62; P<0.001) and nearby bifurcation (OR: 3.20; 95% CI: 1.98-5.16; P<0.001) were positively related to plaque erosion, but not plaque rupture.

CONCLUSIONS

In patients with STEMI, the presence of diabetes mellitus significantly increased the risk of rupture-based STEMI but may not have reduced the risk of plaque erosion-based STEMI in current smokers. Nearby bifurcation and larger MLA were associated with plaque erosion in non-current smokers.

Non-alcoholic fatty liver disease with reduced myocardial FDG uptake is associated with coronary atherosclerosis

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) has a significant role in the development of coronary atherosclerosis, independent of traditional cardiovascular and metabolic risk factors. However, the role of myocardial glucose uptake in NAFLD patients who develop coronary atherosclerosis was unclear. The aim of the present study thus was to investigate the association between NAFLD with characteristic of coronary atherosclerotic plaque and myocardial glucose uptake measured by using 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET).

METHODS AND RESULTS

A total of 418 consecutive subjects who had undergone FDG PET/computed tomography (CT) and coronary computed tomography angiography (CCTA) were retrospectively investigated. Fatty liver was assessed by unenhanced CT. Coronary atherosclerotic plaques and stenosis on CCTA were evaluated. The metabolic parameters were measured on PET images. The ratio of the maximum myocardium FDG value to the mean standardized uptake value of liver (SUVratio) was calculated to estimate myocardial glucose uptake. The association of myocardial glucose uptake with NAFLD and coronary atherosclerosis was determined by multivariate logistic regression analysis. The proportion of low SUVratio in patients with NAFLD was significantly higher compared to those without NAFLD (45.00% vs 19.82%, P < .001). There was a significantly negative correlation between myocardial FDG uptake and hepatic steatosis in association trend analysis (P < .001). When the proportion of individuals with non-calcified plaque on CCTA is stratified by quartiles of SUVratio, patients with low quartiles of SUVratio were more likely to have higher proportion of non-calcified plaque than those with high quartiles of SUVratio (Q1 and Q2 vs Q3 and Q4, P = .003). The trend analysis presented correlated inversely relationship between non-calcified plaque and myocardial SUVratio (P = .001). Moreover, multivariate regression analysis showed that the low SUVratio was independently associated with NAFLD, non-calcified plaque, and significant stenosis after adjusting for clinically important factors.

CONCLUSION

We demonstrated that the presence of reduced myocardial glucose uptake in patients with NAFLD was independently associated with non-calcified plaque and significant stenosis, suggesting an increased risk of coronary atherosclerosis and future cardiovascular events.

Association of systemic inflammatory biomarkers with morphological characteristics of coronary atherosclerotic plaque by intravascular optical coherence tomography

Despite significant advances in preventive, medical, and interventional management, coronary artery disease remains the leading cause of death worldwide. We now know that in the majority of acute coronary syndromes, a thrombotic event is triggered either by the rupture or erosion of the so-called high-risk or 'vulnerable' plaque. However, accurately identifying the individual who is at significant risk of acute event remains the holy grail of preventive cardiology. To better stratify an individual's risk of developing and suffering a cardiovascular event, biomarkers are needed that can accurately predict coronary events and, if possible, monitor disease activity in response to medical or interventional therapies. In order to be able to understand the association of these biomarkers with the morphological substrate of high-risk plaques, intravascular imaging modalities can provide invaluable assistance. Novel imaging tools such as optical coherence tomography (OCT) have not only helped in identifying atherosclerotic plaque characteristics that are unstable but also in estimating global plaque burden. In this study, we provide an overview of our current knowledge of association of various inflammatory markers with atherosclerotic plaque characteristics seen on OCT.

Association between high sensitivity C-reactive protein (hs-CRP) levels and the risk of major adverse cardiovascular events (MACE) and/or microembolic signals after carotid angioplasty and stenting

Background

To evaluate the association between pre/post-procedural high sensitive C-reactive protein (hs-CRP) level and hs-CRP difference, and the risk of major adverse cardiovascular events (MACE) or new diffusion-weighted MRI lesions after carotid angioplasty and stenting (CAS).

Methods

In this study, conducted in 2016 in Shiraz (Iran), patients who underwent diagnostic angiography and CAS were recruited. CAS was performed with distal embolic protection device on patients with both standard and high risk of endarterectomy. Pre/post-procedural hs-CRP, and hs-CRP difference were determined by immunoenzymometric assay method.

Results

A total of 50 patients with diagnostic angiography and 60 patients with CAS were enrolled. No death, myocardial infarction, ischemic or hemorrhagic stroke, and need to revascularization occurred during the 30-days of the post-procedural period. Accordingly, the statistical evaluation in associating MACE and hs-CRP levels was impossible. Angioplasty was associated with higher frequency of elevated post-procedural hs-CRP in comparison to angiography (P=0.003). The higher age, symptomatic lesions, negative history of hypertension, and hs-CRP difference had significant association with the presence of new DWI lesions in univariate analysis (all P<0.05). Angioplasty of left carotid bulb and post-procedural hs-CRP levels was very close to the level of significance (P=0.06). But only left sided lesions had positive association (P=0.037) and hypertension had negative association (P=0.037) in multivariate regression analysis. There were significant association between post-procedural hs-CRP level (P=0.02) and hs-CRP difference (P=0.003), and the number of new lesions; and the hs-CRP difference and the accumulated lesion surface area (P=0.009).

Conclusion

Post-procedural hs-CRP and hs-CRP difference may predict embolic complications of CAS.

Inflammation and coronary artery calcification in South Asians: The Mediators of Atherosclerosis in South Asians Living in America (MASALA) study

BACKGROUND AND AIMS

Inflammatory biomarkers and adipocytokines (IBA) may contribute to atherosclerosis by promoting vascular inflammation. The association between IBA and coronary artery calcium (CAC), a marker of subclinical atherosclerosis, is not well defined in South Asians (SA). We hypothesized that IBA (high sensitivity C-reactive protein [hsCRP], tumor necrosis factor alpha [TNF-α], adiponectin, and leptin) were independently associated with and improved discrimination of CAC among SA.

METHODS

We analyzed IBA and CAC among participants in the prospective Mediators of Atherosclerosis in South Asians Living in America (MASALA) study. We used logistic regression models to examine cross-sectional associations of IBA with CAC presence (CAC >0) and severity (CAC >100), and C-statistics to assess the incremental contribution of each IBA to traditional risk factors (TRF) from the AHA/ACC Pooled Cohort Equations (PCE) for discrimination of CAC.

RESULTS

Among 906 participants in the MASALA study, women (n = 420) had significantly higher levels of hsCRP, adiponectin, and leptin but lower levels of TNF-α than men (p < .01 for all). There was no significant association between any of the four IBA and either CAC category in multivariable-adjusted models, respectively. Lastly, none of the four IBA improved discrimination of CAC presence or severity when added to elements of the PCE.

CONCLUSIONS

IBA were not associated with CAC presence or severity in the MASALA population. IBA did not help identify SA at risk of subclinical atherosclerosis, although associations with ASCVD events remain unclear. In SA, CAC may have a distinct pathophysiology independent of inflammation as measured by IBA.

Detection of Atherosclerotic Plaques in the Rabbit Aorta Using Ultrasound Microbubbles Conjugated to Interleukin-18 Antibodies

BACKGROUND The purpose of the study was to investigate the ability of microbubbles (MBs) targeting interleukin-18 (IL-18) to detect plaques in a rabbit atherosclerotic plaque model. MATERIAL AND METHODS A rabbit atherosclerotic plaque model was established. The locations of the atherosclerotic plaques were verified by two-dimensional scanning and color Doppler flow imaging. An IL-18 antibody was conjugated to naked MBs (MBc) using the biotin-streptavidin conjugation method, resulting in the formation of MBIL-18. MBc and MBIL-18 were then used for contrast-enhanced ultrasound (CEUS) studies. The locations of CD34 and IL-18 within the plaques were determined by immunohistochemistry, and IL-18 expression levels in the plaques were determined by Western blot analysis. The relationships between IL-18 expression and the contrast intensity of the 2 MBs were analyzed. RESULTS MBc and MBIL-18 were both uniformly dispersed. Fluorescence microscopy and flow cytometry revealed that IL-18 was successfully conjugated to MBs. CEUS images showed that the intensity of the MBIL-18 signal was substantially enhanced and prolonged compared with that of the MBc signal. Immunohistochemistry showed that CD34 expression was significantly increased in the plaques and that IL-18 was mainly located in the inner parts and base of the atherosclerotic plaques. Western blot analysis revealed that IL-18 expression was higher in the plaque regions. Correlation analysis showed that IL-18 expression was correlated with the contrast intensity of MBIL-18 (r=0.903, P<0.05) but not with MBc (r=0.540, P>0.05). CONCLUSIONS MBs targeting IL-18 may be a novel, noninvasive method of diagnosing atherosclerotic plaques.

Non-alcoholic fatty liver disease is associated with late but not early atherosclerotic lesions in Chinese inpatients with type 2 diabetes

AIMS

To investigate the association between non-alcoholic fatty liver disease (NAFLD) and carotid and lower limb atherosclerotic lesions in a large group of hospitalized-based type 2 diabetic population and to assess the prevalence and characteristics of NAFLD in Chinese subjects with type 2 diabetes (T2DM).

METHODS

A total of 8571 patients (4804 men) with T2DM were included in this cross-sectional study. The main outcome measures were detection of NAFLD, carotid intima-media thickness (C-IMT), carotid and lower limb atherosclerotic plaque formation, and classical risk factors.

RESULTS

The prevalence of carotid (56.5% vs. 44.5%; p<0.001) and lower limb plaque (56.2% vs. 48.7%; p<0.001), and carotid (11.2% vs. 6.8%; p<0.001) and lower limb stenosis (15.1% vs. 10.3%; p<0.001) was markedly higher in the diabetic patients with NAFLD than in those without, after controlling for age. However, there was no significant difference in C-IMT between diabetic patients with and without NAFLD (0.82±0.30mm vs. 0.85±0.39mm) after controlling for age. Fully adjusted multiple linear regression and logistic regression analyses revealed that NAFLD was significantly associated with increased prevalence of carotid and lower limb atherosclerotic plaque but not with C-IMT. NAFLD, age, sex, longer duration of diabetes and the presence of hypertension were independently associated with carotid and lower limb atherosclerotic plaque (p<0.05).

CONCLUSION

NAFLD was not associated with elevated C-IMT but was associated with carotid and lower limb atherosclerotic plaque independent of conventional cardiovascular disease risk factors and metabolic syndrome in Chinese inpatients with T2DM.

Interleukin-18 gene promoter 607A polymorphism, but not 137C polymorphism, is a protective factor for ischemic stroke in the Chinese population: A meta-analysis

Some epidemiological studies have evaluated the association between interleukin (IL)-18 promoter polymorphisms and the risk of ischemic stroke (IS), but the results were inconsistent. The present meta-analysis was therefore performed to investigate the relationship between IL-18 promoter 137G/C and 607C/A polymorphisms and the risk of IS in the Chinese population. Related studies from PubMed, Embase, Web of Science, CBMdisc and CNKI databases up to November 1, 2014 were systematically searched, also the reference lists of identified articles were manually searched. Information was extracted to calculate for the allelic, genotypic, dominant and recessive models using the pooled odds ratios (ORs) along with 95% confidence intervals (CIs). Evidence of significant association between 607C/A polymorphism and risk of IS was found in four genetic models based on the overall population. However, no significant association between 137G/C polymorphism and risk of IS was found in four genetic models. In summary, the present study suggests that IL-18 gene promoter 607A polymorphism is a protective factor for IS in the Chinese population, while 137C polymorphism has weaker or no protective properties. Still, a larger number of studies with large scale and sufficient original information are required to further confirm our findings.

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We performed a meta-analysis to investigate the relationship between IL-18 gene promoter polymorphisms and ischemic stroke.

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IL-18 gene promoter 607C/A polymorphism is a protective factor for ischemic stroke in the Chinese population.

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This is the first meta-analysis studying such association in Chinese ischemic stroke patients.

Matrix Metalloproteinase-9 as a Marker for Plaque Rupture and a Predictor of Adverse Clinical Outcome in Patients with Acute Coronary Syndrome: An Optical Coherence Tomography Study

OBJECTIVES

The present study sought to clarify the relationship between matrix metalloproteinase-9 (MMP-9) levels and plaque morphology demonstrated by optical coherence tomography (OCT), and to examine their prognostic impacts in patients with acute coronary syndrome (ACS).

METHODS

MMP-9 levels were measured for patients with ACS (n = 249). Among 249 patients, 120 with evaluable OCT images were categorized into patients with ruptured plaques (n = 65) and those with nonruptured plaques (n = 55) on the basis of culprit lesion plaque morphology demonstrated by OCT.

RESULTS

MMP-9 levels on admission were significantly higher in the rupture group than in the nonrupture group (p = 0.029). Although creatine kinase-MB (CK-MB) on admission was comparable between the groups, peak CK-MB was higher in the rupture group than in the nonrupture group (p < 0.001). By receiver operating characteristic curve analysis, the optimal cut-off value of MMP-9 to detect ruptured plaques was 65.5 ng/ml (p = 0.029). There was a nonstatistically significant trend toward increased cardiac death at 2 years (5.9 vs. 1.0%, p = 0.059) in patients with high MMP-9 (≥65.5 ng/ml) compared to those with low MMP-9 (<65.5 ng/ml).

CONCLUSIONS

MMP-9 can differentiate ACS with ruptured plaques from nonruptured plaques, and MMP-9 may be a valuable predictor of long-term cardiac mortality in patients with ACS reflecting plaque rupture.

Association between inflammatory biomarkers and thin-cap fibroatheroma detected by optical coherence tomography in patients with coronary heart disease

INTRODUCTION

The relationship between plaque morphology detected by optical coherence tomography (OCT) and inflammatory biomarkers is not well known.

MATERIAL AND METHODS

This study included 47 patients with ischemic heart disease (22 patients with acute coronary syndrome and 25 patients with effort angina pectoris) who underwent percutaneous coronary intervention (PCI). Before PCI, peripheral blood levels of the inflammatory biomarkers high-sensitivity C-reactive protein (hs-CRP) and interleukin-6 (IL-6) were measured. The OCT can detect thin-cap fibroatheroma (TCFA), a lesion with high potential for adverse cardiac events. We investigated the relationships between TCFAs in culprit lesions detected by OCT and the peripheral blood levels of these biomarkers.

RESULTS

We observed 12 lesions detected as TCFAs. The natural logs of hs-CRP and IL-6 levels in the TCFA group were higher than those in the non-TCFA group (hs-CRP 0.87 (-0.96 to 0.87) vs. -0.47 (-0.92 to 0.30) mg/l, p = 0.027; and IL-6 1.63 (0.63-3.23) vs. 0.53 (-0.21 to 1.05) pg/dl, p = 0.005, respectively). In multivariate logistic regression analysis, log IL-6 was an independent predictor for TCFA detected by OCT (log IL-6, 0.970 pg/dl, p = 0.023). Receiver operating characteristic curve analysis confirmed that IL-6, compared to hs-CRP, has a higher area under the curve for predicting TCFA (0.783 vs. 0.715, respectively).

CONCLUSIONS

Peripheral blood levels of both hs-CRP and IL-6 were associated with TCFAs, as detected by OCT. Moreover, IL-6 has a higher potential than hs-CRP for predicting TCFA.

Low eicosapentaenoic acid to arachidonic acid ratio is associated with thin-cap fibroatheroma determined by optical coherence tomography

BACKGROUND

A low eicosapentaenoic acid (EPA)/arachidonic acid (AA) ratio is known to be associated with cardiovascular events. However, the relationship between the EPA/AA ratio and coronary plaque vulnerability assessed by optical coherence tomography (OCT) has not been examined thoroughly. This study examined the relationship between the EPA/AA ratio and coronary plaque vulnerability assessed by OCT in patients with acute coronary syndrome (ACS).

METHODS

We evaluated 59 ACS patients who had undergone percutaneous coronary intervention using OCT. We divided them into 2 groups according to OCT findings-those with and without thin-cap fibroatheroma (TCFA)-and compared the EPA/AA ratio between the groups.

RESULTS

We identified 32 and 27 patients with and without TCFA, respectively. The EPA/AA ratio was significantly lower in patients with TCFA than in those without TCFA [0.35, interquartile range (0.21-0.44) vs. 0.54, interquartile range (0.42-0.70); p<0.001]. In multivariate logistic regression analysis, the EPA/AA ratio was an independent predictor of TCFA (odds ratio, 0.09; 95% confidence interval, 0.007-0.99; p=0.049). The EPA/AA ratio and fibrous cap thickness showed a significant positive correlation (Spearman ρ=0.46; p<0.001). Furthermore, receiver operating characteristic curve analysis showed that an EPA/AA ratio<0.46 could predict TCFA (81.3%, sensitivity; 74.1%, specificity).

CONCLUSIONS

A low serum EPA/AA ratio is significantly associated with coronary plaque vulnerability assessed by OCT in ACS patients.

High-risk coronary plaque at coronary CT angiography is associated with nonalcoholic fatty liver disease, independent of coronary plaque and stenosis burden: results from the ROMICAT II trial

PURPOSE

To determine the association between nonalcoholic fatty liver disease (NAFLD) and the presence of high-risk coronary atherosclerotic plaque as assessed with coronary computed tomographic (CT) angiography.

MATERIALS AND METHODS

This study was approved by the local ethics committees; informed consent was obtained. Patients randomized to the coronary CT angiography arm of the Rule Out Myocardial Infarction using Computer Assisted Tomography, or ROMICAT, II trial who underwent both nonenhanced CT to assess calcium score and contrast material-enhanced coronary CT angiography were included. Readers assessed coronary CT angiography images for the presence of coronary plaque, significant stenosis (≥50%), and high-risk plaque features (positive remodeling, CT attenuation < 30 HU, napkin-ring sign, spotty calcium). NAFLD was defined as hepatic steatosis at nonenhanced CT (liver minus spleen CT attenuation < 1 HU) without evidence of clinical liver disease, liver cirrhosis, or alcohol abuse. To determine the association between high-risk plaque and NAFLD, univariable and multivariable logistic regression analyses were performed, with high-risk plaque as a dependent variable and NAFLD, traditional risk factors, and extent of coronary atherosclerosis as independent variables.

RESULTS

Overall, 182 (40.9%) of 445 patients had CT evidence of NAFLD. High-risk plaque was more frequent in patients with NAFLD than in patients without NAFLD (59.3% vs 19.0%, respectively; P < .001). The association between NAFLD and high-risk plaque (odds ratio, 2.13; 95% confidence interval: 1.18, 3.85) persisted after adjusting for the extent and severity of coronary atherosclerosis and traditional risk factors.

CONCLUSION

NAFLD is associated with advanced high-risk coronary plaque, independent of traditional cardiovascular risk factors and the extent and severity of coronary artery disease.

The role of the inflammasome in cardiovascular diseases

Inflammasome is a very important signaling platform sensing a variety of triggers of the innate immune system. Inflammasome promotes the production of important pro-inflammatory cytokines such as IL-1β and IL-18. Tight control of inflammasome activity is, therefore, essential and occurs at multiple levels. The activation of inflammasome pathways is linked to the pathogenesis of various prevalent disorders including cardiovascular disease such as atherosclerosis, ischemic injury, cardiomyopathy, and Kawasaki disease. The study of the inflammasome in the cardiovascular system has led to the identification of important triggers and endogenous modulators, and to the exploration of new treatment strategies based on the inhibition of inflammasome activation or its end products, i.e., IL-1β and IL-18. In summary, the discovery of the inflammasome has greatly advanced our understanding of how the innate immune system interferes with cardiovascular disease development and progression, and targeting inflammasome provides new avenues for the treatment and management of cardiovascular diseases.

Advances in mechanisms, imaging and management of the unstable plaque

Post-mortem observations demonstrated that plaque fissure was the final event leading to coronary thrombosis and occlusion in about two-thirds of cases of sudden coronary death. Plaques prone to fissure have, therefore, been defined "vulnerable plaques" and are identified by specific anatomic features including thin inflamed fibrous cap, large lipidic core and positive remodeling. Accordingly, elegant imaging modalities have been developed in order to identify this "holy grail". However, the results of prognostic studies based on the identification of vulnerable plaques have not been encouraging because of the low positive predictive value for major cardiovascular events. This observation is not surprising as the pathogenesis of acute coronary syndromes is complex and multifactorial. In this review we propose a pathogenetic classification of acute coronary syndromes in the attempt to identify homogeneous groups of patients with a common mechanism of coronary instability which can be identified by using specific biomarkers and imaging techniques, and become a specific therapeutic target.

Comparison of Coronary Plaque Components between Non-Culprit Lesions in Patients with Acute Coronary Syndrome and Target Lesions in Patients with Stable Angina: Virtual Histology-Intravascular Ultrasound Analysis

Background and Objectives

The differences in plaque characteristics between non-culprit lesions (NCL) in acute coronary syndrome (ACS) patients (ACS-NCL) and target lesions (TL) in stable angina (SA) patients (SA-TL) are not well understood. We used a virtual histology-intravascular ultrasound (VH-IVUS) to compare the plaque components between ACS-NCL and SA-TL.

Subjects and Methods

We compared VH-IVUS findings between 290 ACS-NCL and 276 SA-TL. VH-IVUS classified the color-coded tissue into four major components: green (fibrotic); yellow-green (fibro-fatty); white {dense calcium (DC)}; and red {necrotic core (NC)}. Thin-cap fibroatheroma (TCFA) was defined as a NC ≥10% of the plaque area in at least 3 consecutive frames without overlying fibrous tissue in the presence of ≥40% plaque burden.

Results

Although the plaque burden was significantly smaller (52±13% vs. 54±14%, p=0.044), ACS-NCL had a greater %NC area (17.9±11.6% vs. 14.3±8.7%, p<0.001) and %DC area (9.7±9.8% vs. 8.1±8.0%, p=0.032) compared with SA-TL at the minimum lumen site. By volumetric analysis, ACS-NCL had a greater %NC volume (15.8±9.2% vs. 13.9±7.4%, p=0.006) compared with SA-TL. TCFA was observed more frequently in ACS-NCL compared with SA-TL (27.6% vs. 18.1%, p=0.032). Independent predictors of TCFA by multivariate analysis were ACS {odds ratio (OR): 2.204, 95% CI: 1.321-3.434, p=0.021} and high-sensitivity C-reactive protein (OR: 1.101; 95% CI 1.058-1.204, p=0.035).

Conclusion

Although the plaque burden was significantly smaller, ACL-NCL had more vulnerable plaque components compared with SA-TL, and ACS and high-sensitivity C-reactive protein were the independent predictors of TCFA.

Mechanisms of Coronary Thrombosis in Cigarette Smoke Exposure

Acute rupture or erosion of a coronary atheromatous plaque and subsequent coronary artery thrombosis cause the majority of sudden cardiac deaths and myocardial infarctions. Cigarette smoking is a major risk factor for acute coronary thrombosis. Indeed, a majority of sudden cardiac deaths attributable to acute thrombosis are in cigarette smokers. Both active and passive cigarette smoke exposure seem to increase the risk of coronary thrombosis and myocardial infarctions. Cigarette smoke exposure seems to alter the hemostatic process via multiple mechanisms, which include alteration of the function of endothelial cells, platelets, fibrinogen, and coagulation factors. This creates an imbalance of antithrombotic/prothrombotic factors and profibrinolytic/antifibrinolytic factors that support the initiation and propagation of thrombosis.

Coronary plaque component in patients with vasospastic angina: a virtual histology intravascular ultrasound study

BACKGROUND

Coronary spasm plays an important role in the pathogenesis of ischemic heart disease. However, tissue components of coronary plaque in patients with vasospastic angina (VSA) have been unknown. This study used virtual histology (VH)-intravascular ultrasound (IVUS) to elucidate the tissue component of spastic coronary arteries and its gender differences in patients with VSA.

METHODS

According to acetylcholine provocation tests, the study subjects (42 patients [19 men, 23 women, 61 ± 13 years]) were divided into 2 groups: the VSA group of 26 patients and the non-VSA group of 16 patients. After nitrate injection, IVUS volumetric analysis was done, and the parameters were compared between the groups.

RESULTS

Although clinical demographics were almost identical between the groups, VSA group had lower plasma adiponectin level (5.9 ± 3.3 μg/ml vs. 11.2 ± 7.6 μg/ml, p=0.007) and tended to have higher high-sensitivity C-reactive protein (0.15 ± 0.24 mg/dl vs. 0.06 ± 0.04 mg/dl, p=0.1) than non-VSA group. VSA group had diffusely thickened intima (% plaque volume, 34 ± 11% vs. 27 ± 7%, p=0.01) compared with non-VSA group. However, plaque components of patients with VSA were similar with that of non-VSA patients (dense calcium, 4 ± 6% vs. 3 ± 4%; necrotic core, 10 ± 9% vs. 8 ± 6%; fibrofatty, 19 ± 16% vs. 22 ± 11%; and fibrous, 67 ± 16% vs. 67 ± 9%). Although male patients with VSA had atherogenic lipid and metabolic profiles than female VSA patients, there were no significant gender differences in the volumetric IVUS parameters and plaque components.

CONCLUSIONS

Compared with non-VSA patients, VSA patients had diffusely thickened fibrous-dominant coronary plaque without gender difference, and that might suggest the role of vasospasm in the development of atherosclerosis.

Molecular imaging to identify the vulnerable plaque--from basic research to clinical practice

Cardiovascular disease (CVD) is still the leading cause of death in the Western World. Adverse outcomes of CVD include stroke, myocardial infarction, and heart failure. Atherosclerosis is considered to be the major cause of CVD and is estimated to cause half of all deaths in developed countries. Atherosclerotic lesions of the vessel wall may obstruct blood flow mechanically through stenosis, but rupture of atherosclerotic plaques causing formation of occlusive thrombi is far more prevalent. Unfortunately, conventional diagnostic tools fail to assess whether a plaque is vulnerable to rupture. Research over the past decade identified the biological processes that are implicated in the course towards plaque rupture, like cell death and inflammation. Knowledge about plaque biology propelled the development of imaging techniques that target biologic processes in order to predict the vulnerable plaque. This paper discusses novel and existing molecular imaging targets and addresses advantages and disadvantages of these targets and respective imaging techniques in respect of clinical application and socio-economic impact.

The biology behind the atherothrombotic effects of cigarette smoke

Cigarette smoke is an aerosol that contains >4,000 chemicals, including nicotine, carbon monoxide, acrolein, and oxidant compounds. Exposure to cigarette smoke induces multiple pathological effects in the endothelium, several of which are the result of oxidative stress initiated by reactive oxygen species, reactive nitrogen species, and other oxidant constituents of cigarette smoke. Cigarette-smoke exposure interferes adversely with the control of all stages of plaque formation and development and pathological thrombus formation. The reactive oxygen species in cigarette smoke contribute to oxidative stress, upregulation of inflammatory cytokines, and endothelial dysfunction, by reducing the bioavailability of nitric oxide. Plaque formation and the development of vulnerable plaques also result from exposure to cigarette smoke via the enhancement of inflammatory processes and the activation of matrix metalloproteases. Moreover, exposure to cigarette smoke results in platelet activation, stimulation of the coagulation cascade, and impairment of anticoagulative fibrinolysis. Many cigarette-smoke-mediated prothrombotic changes are quickly reversible upon smoking cessation. Public health efforts should urgently promote our understanding of current cigarette-smoke-induced cardiovascular pathology to encourage individuals to reduce their exposure to cigarette smoke and, therefore, the detrimental consequences of associated atherothrombotic disease.