Multicentric inflammation in epicardial coronary arteries of patients dying of acute myocardial infarction

The Hippo-YAP pathway in various cardiovascular diseases: Focusing on the inflammatory response

The Hippo pathway was initially discovered in Drosophila melanogaster and mammals as a key regulator of tissue growth both in physiological and pathological states. Numerous studies depict the vital role of the Hippo pathway in cardiovascular development, heart regeneration, organ size and vascular remodeling through the regulation of YAP (yes-associated protein) translocation. Recently, an increasing number of studies have focused on the Hippo-YAP pathway in inflammation and immunology. Although the Hippo-YAP pathway has been revealed to play controversial roles in different contexts and cell types in the cardiovascular system, the mechanisms regulating tissue inflammation and the immune response remain to be clarified. In this review, we summarize findings from the past decade on the function and mechanism of the Hippo-YAP pathway in CVDs (cardiovascular diseases) such as myocardial infarction, cardiomyopathy and atherosclerosis. In particular, we emphasize the role of the Hippo-YAP pathway in regulating inflammatory cell infiltration and inflammatory cytokine activation.

Integrated RNA gene expression analysis identified potential immune-related biomarkers and RNA regulatory pathways of acute myocardial infarction

Background

Acute lesions are among the most important causes of death due to vascular lesions worldwide. However, there are no accurate genetic markers for Acute myocardial infarction (AMI). This project will use microarray integration analysis in bioinformatics analysis to find and validate relevant AMI gene markers.

Methods

Five microarray gene expression datasets were downloaded through the GEO database. We identified 50 significant DEGs by comparing and analyzing gene expression between 92 AMI and 57 standard samples. The BioGPS database screened differentially expressed genes specific to the immune system. DEGs were mainly involved in immune-related biological processes based on Enrichment analysis. Eight hub genes and three-gene cluster modules were subsequently screened using Cytoscape and validated using Box plot’s grouping comparison and ROC curves. Combined group comparison results and ROC curves analysis concluded that AQP9, IL1B, and IL1RN might be potential gene markers for the AMI process. We used the StarBase database to predict target miRNAs for eight essential genes. The expected results were used to screen and obtain target lncRNAs. Then Cytoscape was used to create CeRNA networks. By searching the literature in PubMed, we concluded that AQP9, IL1B, and IL1RN could be used as gene markers for AMI, while FSTL3-miR3303p-IL1B/IL1RN and ACSL4-miR5905p-IL1B could be used as RNA regulatory pathways affecting AMI disease progression.

Conclusions

Our study identified three genes that may be potential genetic markers for AMI’s early diagnosis and treatment. In addition, we suggest that FSTL3-miR-330-3p-IL1B/IL1RN and ACSL4-miR-590-5p-IL1B may be possible RNA regulatory pathways to control AMI disease progression.

Argyrophilic Nucleolar Organizer Regions as New Biomarkers in ST-Elevation Myocardial Infarction

(1) Background: ST-elevation myocardial infarction (STEMI) is an inflammatory disease in which neutrophils, macrophages, and lymphocytes accumulate in the ischemic myocardium and have important functions. Nucleolar-organizing regions (NORs) are the site of the ribosomal genes composed of ribosomal DNA and proteins. We aimed to evaluate AgNOR proteins, which have never been studied in patients with STEMI in the literature. (2) Methods: A total of 140 participants (75 with STEMI and 65 volunteers without any diagnosis of acute coronary syndrome) were included in this study. Echocardiography was carried out, and mean AgNOR number and total AgNOR area/total nuclear area (TAA/TNA) were evaluated for all individuals. (3) Results: The mean AgNOR number and TAA/TNA ratio were significantly higher in the STEMI group than the control (p < 0.001). Statistically significant relations between both TAA/TNA ratio and mean AgNOR number and interventricular septal thickness, fasting blood sugar, creatinine, HDL, hemoglobin (g/dL), WBC (µL/mL), monocytes, neutrophils, and neutrophil/lymphocyte ratio were detected (p < 0.05). Moreover, a statistically significant relation between LDL (mg/dL) and mean AgNOR number (p = 0.005) was detected. (4) Conclusion: Both AgNOR protein amounts increase depending on the hypoxia that occurs in STEMI. The AgNOR proteins may thus be promising markers in STEMI.

Ischemia-reperfusion injury to coronary arteries: Comprehensive microscopic study after reperfused myocardial infarction

BACKGROUND

Coronary arteries supply oxygen and nutrients to the heart. We evaluated the dynamics of microscopic damage throughout the ischemia-reperfusion process in the wall of coronary arteries following myocardial infarction (MI).

METHODS

In a swine model of reperfused MI, animals were divided into one control and four MI groups: 90-min ischemia without reperfusion, or followed by one minute, one week or one month reperfusion. Left anterior descending (LAD; infarct-related artery) and control right coronary arteries (RCA) were isolated. Taking the balloon inflation region as a reference, we isolated the proximal and distal LAD areas, performing histological staining and immunohistochemistry.

RESULTS

Although mild changes in tunica intima were observed during ischemia, an almost complete absence of endothelium, and abnormal breaks in the internal elastic layer were found post-revascularization. In tunica media, increased thickness was observed soon after reperfusion, whereas larger thickness, disorganized muscle cell distribution and edema were found one week after reperfusion. This damage was more pronounced in distal rather than proximal LAD, whereas no changes were detected in RCA. In the tunica adventitia, vasa vasorum density decayed during ischemia in both LAD regions, but was restored after one month. Leukocyte adhesion to the artery was observed post-revascularization, developing into a massive presence in the three layers one week post-reperfusion.

CONCLUSIONS

Ischemia-reperfusion can itself induce damage in the wall of the epicardial coronary artery, becoming more pronounced in the region distal to balloon inflation. Exploring these abnormalities will provide insight into the pathophysiology of coronary circulation and MI.

Efficacy and Safety of Colchicine in Post-acute Myocardial Infarction Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background: Inflammation plays a key role in atherosclerotic plaque destabilization and adverse cardiac remodeling. Recent evidence has shown a promising role of colchicine in patients with coronary artery disease. We evaluated the efficacy and safety of colchicine in post–acute myocardial infarction (MI) patients.

Methods: We searched five electronic databases from inception to January 18, 2021, for randomized controlled trials (RCTs) evaluating colchicine in post–acute MI patients. Primary outcomes were cardiovascular mortality and recurrent MI. Secondary outcomes were all-cause mortality, stroke, urgent coronary revascularization, levels of follow-up high-sensitivity C-reactive protein (hs-CRP), and drug-related adverse events. All meta-analyses used inverse-variance random-effects models.

Results: Six RCTs involving 6,005 patients were included. Colchicine did not significantly reduce cardiovascular mortality [risk ratio (RR), 0.91; 95% confidence interval (95% CI), 0.52–1.61; p = 0.64], recurrent MI (RR, 0.87; 95% CI, 0.62–1.22; p = 0.28), all-cause mortality (RR, 1.06; 95% CI, 0.61–1.85; p = 0.78), stroke (RR, 0.28; 95% CI, 0.07–1.09; p = 0.05), urgent coronary revascularization (RR, 0.46; 95% CI, 0.02–8.89; p = 0.19), or decreased levels of follow-up hs-CRP (mean difference, −1.95 mg/L; 95% CI, −12.88 to 8.98; p = 0.61) compared to the control group. There was no increase in any adverse events (RR, 0.97; 95% CI, 0.89–1.07; p = 0.34) or gastrointestinal adverse events (RR, 2.49; 95% CI, 0.48–12.99; p = 0.20). Subgroup analyses by colchicine dose (0.5 vs. 1 mg/day), time of follow-up (<1 vs. ≥1 year), and treatment duration (≤30 vs. >30 days) showed no changes in the overall findings.

Conclusion: In post–acute MI patients, colchicine does not reduce cardiovascular or all-cause mortality, recurrent MI, or other cardiovascular outcomes. Also, colchicine did not increase drug-related adverse events.

Tumour necrosis factor receptor-associated factors: interacting protein with forkhead-associated domain inhibition decreases inflammatory cell infiltration and cardiac remodelling after acute myocardial infarction

OBJECTIVES

Acute myocardial infarction (AMI) is a leading cause of morbidity and mortality worldwide. Post-AMI cardiac remodelling is closely related to the prognosis of AMI. The excess inflammatory responses could promote cardiac remodelling. Tumour necrosis factor receptor-associated factor-interacting protein with forkhead-associated domain (TIFA) has been identified as a nuclear factor (NF)-κB activator, which plays a key role in the activation of the NF-κB signalling pathway. The goal of this research was to investigate the expression and the underlying mechanism of TIFA in an AMI mouse model.

METHODS

The AMI mouse model was induced by ligation of the left coronary artery. TIFA and NF-κB knockdown were established by lentivirus transduction. The expression levels of associated proteins were analysed by a western blot or an enzyme-linked immunosorbent assay. Histological characteristics were evaluated by haematoxylin-eosin staining.

RESULTS

The TIFA level was elevated in our AMI mouse model. The production of interleukin-1β and tumour necrosis factor-α increased markedly in the mice with AMI. TIFA knockdown inhibited the infiltration of inflammatory cells, production of pro-inflammatory mediators (interleukin-1β and tumour necrosis factor-α), NF-κB activation and cardiac remodelling (matrix metallopeptidase 9) post-AMI. In addition, NF-κB knockdown could also alleviate cardiac remodelling after AMI.

CONCLUSIONS

The preceding results indicated that TIFA inhibition could ameliorate cardiac remodelling after AMI partly through inactivation of NF-κB. This study provides insights into further research of cardiac remodelling and AMI from bench to clinic.

Sustained Focal Vascular Inflammation Accelerates Atherosclerosis in Remote Arteries

OBJECTIVE

Evidence from preclinical and clinical studies has demonstrated that myocardial infarction promotes atherosclerosis progression. The impact of focal vascular inflammation on the progression and phenotype of remote atherosclerosis remains unknown. Approach and Results: We used a novel ApoE^-/- knockout mouse model of sustained arterial inflammation, initiated by mechanical injury in the abdominal aorta. Using serial in vivo molecular MRI and ex vivo histology and flow cytometry, we demonstrate that focal arterial inflammation triggered by aortic injury, accelerates atherosclerosis in the remote brachiocephalic artery. The brachiocephalic artery atheroma had distinct histological features including increased plaque size, plaque permeability, necrotic core to collagen ratio, infiltration of more inflammatory monocyte subsets, and reduced collagen content. We also found that arterial inflammation following focal vascular injury evoked a prolonged systemic inflammatory response manifested as a persistent increase in serum IL-6 (interleukin 6). Finally, we demonstrate that 2 therapeutic interventions-pravastatin and minocycline-had distinct anti-inflammatory effects at the plaque and systemic level.

CONCLUSIONS

We show for the first time that focal arterial inflammation in response to vascular injury enhances systemic vascular inflammation, accelerates remote atheroma progression and induces plaques more inflamed, lipid-rich, and collagen-poor in the absence of ischemic myocardial injury. This inflammatory cascade is modulated by pravastatin and minocycline treatments, which have anti-inflammatory effects at both plaque and systemic levels that mitigate atheroma progression.

Characteristics of T cell receptor repertoires of patients with acute myocardial infarction through high-throughput sequencing

Background

T cells are key regulators of immunity and one of the cells recruited in atherosclerosis and participated in various stages of the development of atherosclerosis. Characterizing T-cell receptor (TCR) repertoires is a priority of great scientific interest and potential clinical utility for the early diagnosis, risk stratification and prognostic evaluation of acute myocardial infarction (AMI).

Methods

The TCR repertoires in 21 subjects including 7 patients with non-ST-segment elevation myocardial infarction (NSTEMI), 6 patients with ST-segment elevation myocardial infarction (STEMI) and 8 subjects with normal coronary artery (NCA) as control were characterized by using high-throughput sequencing. Bioinformatics analysis were performed.

Results

Patients with NSTEMI displayed more diverse TCR sequences than NCA controls, but they had lower percentage of top 200 TCR sequences. However, no significant differences were observed between the patients with STEMI and NCA controls, but STEMI group had lower percentage of top 200 TCR sequences. T cells from patients with AMI and NCA controls showed a differential V and J gene usage, especially, significant difference was observed in frequencies of V gene (TRBV2, TRBV29-1, TRBV30 and TRBV12-3) and J gene (TRBJ2-1) usage. Furthermore, significantly differences in average overlap was observed in groups of AMI and NCA control. The results showed that patients with AMI had distinct TCR repertoires which revealed the association between cardiovascular condition and T-cell clonotypes.

Conclusions

Our findings revealed the differences of TCR repertoires between patients with AMI and NCA controls, which might be potential biomarkers for evaluating risk stratification or diagnosis of acute coronary syndrome.

Electronic supplementary material

The online version of this article (10.1186/s12967-019-1768-8) contains supplementary material, which is available to authorized users.

Update on the Protective Role of Regulatory T Cells in Myocardial Infarction: A Promising Therapy to Repair the Heart

Myocardial infarction (MI) remains one of the leading causes of heart failure development and death worldwide. To date, interventional and pharmacological therapies are effective in reducing the onset of heart failure and promoting survival. However, progressive maladaptive remodeling post-MI persists in a large fraction of patients resulting in poor prognosis. Immune cell responses and an inflammatory environment largely contribute to adverse cardiac remodeling post-MI. CD4FOXP3 regulatory T cells (Tregs) are known for their immunosuppressive capacity and have been successfully implemented in multiple preclinical studies of permanent and ischemia-reperfusion MI. In this review, we highlight the important cardioprotective role of Tregs at the cardiac tissue, cellular, and molecular level, as well as the most prominent pharmacological venues that could be used to exploit Tregs as a novel therapeutic intervention to lessen myocardial injury post-MI.

Lymphocytic myocarditis occurs with myocardial infarction and coincides with increased inflammation, hemorrhage and instability in coronary artery atherosclerotic plaques

OBJECTIVE

Although lymphocytic myocarditis (LM) clinically can mimic myocardial infarction (MI), they are regarded as distinct clinical entities. However, we observed a high prevalence (32%) of recent MI in patients diagnosed post-mortem with LM. To investigate if LM changes coronary atherosclerotic plaque, we analyzed in autopsied hearts the inflammatory infiltrate and stability in coronary atherosclerotic lesions in patients with LM and/or MI.

METHODS

The three main coronary arteries were isolated at autopsy of patients with LM, with MI of 3-6h old, with LM and MI of 3-6h old (LM+MI) and controls. In tissue sections of atherosclerotic plaque-containing coronary segments inflammatory infiltration, plaque stability, intraplaque hemorrhage and thrombi were determined via (immuno)histological criteria.

RESULTS

In tissue sections of those coronary segments the inflammatory infiltrate was found to be significantly increased in patients with LM, LM+MI and MI compared with controls. This inflammatory infiltrate consisted predominantly of macrophages and neutrophils in patients with only LM or MI, of lymphocytes in LM+MI and MI patients and of mast cells in LM+MI patients. Moreover, in LM+MI and MI patients this coincided with an increase of unstable plaques and thrombi. Finally, LM and especially MI and LM+MI patients showed significantly increased intraplaque hemorrhage.

CONCLUSIONS

This study demonstrates prevalent co-occurrence of LM with a very recent MI at autopsy. Moreover, LM was associated with remodeling and inflammation of atherosclerotic plaques indicative of plaque destabilization pointing to coronary spasm, suggesting that preexistent LM, or its causes, may facilitate the development of MI.

The Systematic Evaluation of Identifying the Infarct Related Artery Utilizing Cardiac Magnetic Resonance in Patients Presenting with ST-Elevation Myocardial Infarction

Background

Identification of the infarct-related artery (IRA) in patients with STEMI using coronary angiography (CA) is often based on the ECG and can be challenging in patients with severe multi-vessel disease. The current study aimed to determine how often percutaneous intervention (PCI) is performed in a coronary artery different from the artery supplying the territory of acute infarction on cardiac magnetic resonance imaging (CMR).

Methods

We evaluated 113 patients from the Reduction of infarct Expansion and Ventricular remodeling with Erythropoetin After Large myocardial infarction (REVEAL) trial, who underwent CMR within 4±2 days of revascularization. Blinded reviewers interpreted CA to determine the IRA and CMR to determine the location of infarction on a 17-segment model. In patients with multiple infarcts on CMR, acuity was determined with T2-weighted imaging and/or evidence of microvascular obstruction.

Results

A total of 5 (4%) patients were found to have a mismatch between the IRA identified on CMR and CA. In 4/5 cases, there were multiple infarcts noted on CMR. Thirteen patients (11.5%) had multiple infarcts in separate territories on CMR with 4 patients (3.5%) having multiple acute infarcts and 9 patients (8%) having both acute and chronic infarcts.

Conclusions

In this select population of patients, the identification of the IRA by CA was incorrect in 4% of patients presenting with STEMI. Four patients with a mismatch had an acute infarction in more than one coronary artery territory on CMR. The role of CMR in patients presenting with STEMI with multi-vessel disease on CA deserves further investigation.

Rare case of proximal coronary plaque regression after distal arterial grafting

The metabolically active endothelium of arterial grafts is reported to slow the atherosclerotic process in the distal coronary territories to which they are grafted with improved patency. The literature on arterial grafting causing proximal plaque regression is scant. We report here a case of proximal left anterior descending artery (LAD) plaque regression following distal arterial grafting with a left internal mammary arterial (LIMA) graft to LAD. This rarely documented regression resulted in “stringing” of the arterial graft, while there was a significant progression of atherosclerotic disease in the right coronary with patent venous graft and de novo lesion in circumflex territory necessitating percutaneous coronary intervention, in spite of aggressive medical therapy. The dichotomous progression of disease in two out of three coronary arterial systems and regression of the proximal plaque in LAD grafted with LIMA 12 years ago suggests the protective effect of arterial grafting in reversing the atherosclerotic process.

Systemic Versus Coronary Levels of Inflammation in Acute Coronary Syndromes

To address a possible link between systemic and coronary inflammation in the setting of acute coronary syndromes, the authors examined both levels of 3 inflammatory mediators such as high sensitive C-reactive protein (hs-CRP), interleukin (IL)-6, and matrix metalloproteinase (MMP)-9 in patients with the early phase of acute myocardial infarction (AMI). In total, 20 patients with AMI showing minimal elevation of cardiac enzymes were studied. Before angioplasty, peripheral blood and culprit coronary thrombus were sampled to compare systemic and coronary levels of hs-CRP, IL-6, and MMP-9. Relation of systemic levels of hs-CRP and IL-6 to culprit coronary morphology was also evaluated by the use of intravascular ultrasound. Systemic and coronary levels of hs-CRP were nearly equivalent (4.3 ±5.0 vs 4.7 ±5.4 mg/L, p=0.279), whereas IL-6 and MMP-9 showed higher in coronary levels than in systemic levels (169 ±154 vs 93 ±107 pg/mL, p=0.002 and 164 ±116 vs 103 ±94 ng/mL, p=0.018, respectively). Systemic levels of hs-CRP were correlated with coronary levels of IL-6 (r =0.566, p=0.009). Culprit coronary plaque area demonstrated a positive relation with systemic levels of hs-CRP (r =0.466, p=0.038) and also IL-6 (r =0.707, p<0.001). The present study may provide an important insight into the link between systemic and coronary levels of inflammation, which is also associated with vulnerable coronary morphology in the setting of acute coronary syndromes.

A phase 2 randomized, double-blind, placebo-controlled study of the effect of VIA-2291, a 5-lipoxygenase inhibitor, on vascular inflammation in patients after an acute coronary syndrome

OBJECTIVE

Arachidonate 5-lipoxygenase (5-LO) is a key enzyme in the synthesis of leukotrienes. VIA-2291 is a potent 5-LO inhibitor, which has been shown to reduce hsCRP and noncalcified coronary plaque volume following an acute coronary syndrome (ACS). We aim to evaluate the effect of VIA-2291 on vascular inflammation compared to placebo using FDG-PET.

METHODS

A Phase II, randomized, double-blind, parallel-group study was conducted in 52 patients with recent ACS assigned 1:1 to either 100 mg VIA-2291 or placebo for 24 weeks. The primary outcome was the effect of VIA-2291 relative to placebo on arterial inflammation detected by (18)fluorodeoxyglucose positron emission tomography (FDG-PET) within the index vessel after 24 weeks of daily treatment, compared to baseline.

RESULTS

VIA-2291 was relatively well tolerated and was associated with a significant inhibition of the potent chemo-attractant LTB4, with a mean inhibition of activity of 92.8% (p<0.0001) at 6 weeks in the VIA-2291 group, without further significant change in inhibition at 24 weeks. However, for VIA-2291 was not associated with significant difference in inflammation (target-to-background ratio) compared to placebo at 24 weeks or 6 weeks of treatment. Further, VIA-2291 was not associated with a significant reduction in hsCRP from baseline after either 6 or 24 weeks of treatment.

CONCLUSIONS

VIA-2291 is well-tolerated and effectively reduces leukotriene production. However, inhibition of 5-LO with VIA-2291 is not associated with significant reductions in vascular inflammation (by FDG-PET) or in blood inflammatory markers. Accordingly, this study does not provide evidence to support a significant anti-inflammatory effect of VIA-2291 in patients with recent ACS.

Multiple coronary plaque ruptures in a patient with a recent ST-elevation acute myocardial infarction causing recurrent coronary instability

Multiple plaque instability has been reported in about one-third of patients with ST elevation acute myocardial infarction (STEMI) and could be responsible for early recurrent instability after STEMI. Optical coherence tomography (OCT) is a high-resolution imaging technique that may help in detection and characterization of unstable coronary plaques. We present a case of multiple coronary instability in a patient with anterior STEMI where OCT has tailored an optimal diagnosis and treatment.

Positron emission tomography in acute coronary syndromes

Several imaging techniques have been used to assess cardiac structure and function, to understand pathophysiology, and to guide clinical decision making in the setting of acute coronary syndromes (ACS). Over the last years, cardiac positron emission tomography (PET) has affirmed its role in this setting. Indeed, the combined quantitative assessment of myocardial metabolism and perfusion has allowed to better understand the functional status of infarcted and non-infarcted myocardium, thus improving our knowledge of myocardial response to necrosis. More recently, several studies, taking advantage of previous observations in patients with cancer, have shown that PET could also provide important information on the mechanisms of vascular instability through the early identification of activated inflammatory cells in the atherosclerotic plaque. These findings are opening the way to more effective forms of prevention of acute vascular syndromes in high-risk patients; furthermore, new more sensitive and specific tracers for the identification of vascular inflammation are under development. In this review, we describe the potential and limitations of PET in the assessment of ACS.

Fibroblast activation protein is induced by inflammation and degrades type I collagen in thin-cap fibroatheromata

Aims

Collagen degradation in atherosclerotic plaques with thin fibrous caps renders them more prone to rupture. Fibroblast activation protein (FAP) plays a role in arthritis and tumour formation through its collagenase activity. However, the significance of FAP in thin-cap human fibroatheromata remains unknown.

Methods and results

We detected enhanced FAP expression in type IV–V human aortic atheromata (n = 12), compared with type II–III lesions (n = 9; P < 0.01) and healthy aortae (n = 8; P < 0.01) by immunostaining and western blot analyses. Fibroblast activation protein was also increased in thin-cap (<65 µm) vs. thick-cap (≥65 µm) human coronary fibroatheromata (n = 12; P < 0.01). Fibroblast activation protein was expressed by human aortic smooth muscle cells (HASMC) as shown by colocalization on immunofluorescent aortic plaque stainings (n = 10; P < 0.01) and by flow cytometry in cell culture. Although macrophages did not express FAP, macrophage burden in human aortic plaques correlated with FAP expression (n = 12; R²= 0.763; P < 0.05). Enzyme-linked immunosorbent assays showed a time- and dose-dependent up-regulation of FAP in response to human tumour necrosis factor α (TNFα) in HASMC (n = 6; P < 0.01). Moreover, supernatants from peripheral blood-derived macrophages induced FAP expression in cultured HASMC (n = 6; P < 0.01), an effect abolished by blocking TNFα (n = 6; P < 0.01). Fibroblast activation protein associated with collagen-poor regions in human coronary fibrous caps and digested type I collagen and gelatin in vitro (n = 6; P < 0.01). Zymography revealed that FAP-mediated collagenase activity was neutralized by an antibody directed against the FAP catalytic domain both in HASMC (n = 6; P < 0.01) and in fibrous caps of atherosclerotic plaques (n = 10; P < 0.01).

Conclusion

Fibroblast activation protein expression in HASMC is induced by macrophage-derived TNFα. Fibroblast activation protein associates with thin-cap human coronary fibroatheromata and contributes to type I collagen breakdown in fibrous caps.

Rosuvastatin, inflammation, C-reactive protein, JUPITER, and primary prevention of cardiovascular disease--a perspective

The major public health concern worldwide is coronary heart disease, with dyslipidemia as a major risk factor. Statin drugs are recommended by several guidelines for both primary and secondary prevention. Rosuvastatin has been widely accepted because of its efficacy, potency, and superior safety profile. Inflammation is involved in all phases of atherosclerosis, with the process beginning in early youth and advancing relentlessly for decades throughout life. C-reactive protein (CRP) is a well-studied, nonspecific marker of inflammation which may reflect general health risk. Considerable evidence suggests CRP is an independent predictor of future cardiovascular events, but direct involvement in atherosclerosis remains controversial. Rosuvastatin is a synthetic, hydrophilic statin with unique stereochemistry. A large proportion of patients achieve evidence-based lipid targets while using the drug, and it slows progression and induces regression of atherosclerotic coronary lesions. Rosuvastatin lowers CRP levels significantly. The Justification for Use of statins in Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER) trial was designed after the observation that when both low density lipoprotein and CRP were reduced, patients fared better than when only LDL was lowered. Advocates and critics alike acknowledge that the benefits of rosuvastatin in JUPITER were real. After a review, the US Food and Drug Administration extended the indications for rosuvastatin to include asymptomatic JUPITER-eligible individuals with one additional risk factor. The American Heart Association and Centers of Disease Control and Prevention had previously recognized the use of CRP in persons with "intermediate risk" as defined by global risk scores. The Canadian Cardiovascular Society guidelines went further and recommended use of statins in persons with low LDL and high CRP levels at intermediate risk. The JUPITER study focused attention on ostensibly healthy individuals with "normal" lipid profiles and high CRP values who benefited from statin therapy. The backdrop to JUPITER during this period was an increasing awareness of a rising cardiovascular risk burden and imperfect methods of risk evaluation, so that a significant number of individuals were being denied beneficial therapies. Other concerns have been a high level of residual risk in those who are treated, poor patient adherence, a need to follow guidelines more closely, a dual global epidemic of obesity and diabetes, and a progressively deteriorating level of physical activity in the population. Calls for new and more effective means of reducing risk for coronary heart disease are intensifying. In view of compelling evidence supporting earlier and aggressive therapy in people with high risk burdens, JUPITER simply offers another choice for stratification and earlier risk reduction in primary prevention patients. When indicated, and in individuals unwilling or unable to change their diet and lifestyles sufficiently, the benefits of statins greatly exceed the risks. Two side effects of interest are myotoxicity and an increase in the incidence of diabetes.

The aorta wall of patients presenting to the emergency department with acute myocardial infarction by cardiac magnetic resonance

BACKGROUND

Inflammation has been shown to be a major component in the pathophysiology of acute coronary syndrome (ACS). In patients presenting with acute myocardial infarction (AMI), a critical component of the ACS spectrum, multiple coronary arteries are involved during this inflammatory process. In addition to the coronary vasculature, the inflammatory cascade has also been shown to affect the carotid arteries and possibly the aorta.

PURPOSE

To assess the involvement of the aorta during AMI by cardiac magnetic resonance (CMR).

METHODS

We prospectively evaluated the aortic wall by CMR in 123 patients. 78 patients were enrolled from the emergency department (ED), who presented with chest pain and were classified as either: (1) AMI: elevated troponin levels and typical chest pain or (2) non-cardiac chest pain (CP): negative troponins and a normal stress test or normal cardiac catheterization. We compared these 2 groups to a group of 45 asymptomatic diabetic patients. The descending thoracic aortic wall area (AWA) and maximal aortic wall thickness (AWT) were measured using a double inversion recovery T-2 weighted, ECG-gated, spin echo sequence by CMR.

RESULTS

Patients with AMI were older, more likely to smoke, had a higher incidence of claudication, and had higher CRP levels. The AWA and maximal AWT were greater in patients who presented to the ED with ACS (2.11+/-0.17 mm(2), and 3.17+/-0.19 mm, respectively) than both patients presenting with non-cardiac CP (1.52+/-0.58 mm(2), p<0.001; and 2.57+/-0.10 mm, p<0.001) and the diabetic patients (1.38+/-0.58 mm(2), p<0.001; and 2.30+/-0.131 mm, p<0.001). The difference in the aortic wall characteristics remained significant after correcting for body mass index, hyperlipidemia, statins and C-reactive protein. There was no difference in maximal AWT or AWA between patients with non-cardiac CP and patients with diabetes.

CONCLUSION

Patients with AMI have a significantly greater maximal aortic wall thickness and area compared to patients with non-cardiac CP. Longitudinal studies are needed to assess whether this increase is due to inflammation or a higher atherosclerotic burden.

Detection of the vulnerable coronary atheromatous plaque. Where are we now?

Atherosclerosis is a progressive process with potentially devastating consequences and has been identified as the leading cause of morbidity and mortality, especially in the industrial countries. The underlying mechanisms include endothelial dysfunction, lipid accumulation and enhanced inflammatory involvement resulting in plaque disruption or plaque erosion and subsequent thrombosis. However, it has been made evident, that the majority of rupture prone plaques that produce acute coronary syndromes are not severely stenotic. Conversely, lipid-rich plaques with thin fibrous cap, heavily infiltrated by inflammatory cells have been shown to predispose to rupture and thrombosis, independently of the degree of stenosis. Therefore, given the importance of plaque composition, a continuously growing interest in the development and improvement of diagnostic modalities will promptly and most importantly, accurately detect and characterize the high-risk atheromatous plaque. Use of these techniques may help risk stratification and allow the selection of the most appropriate therapeutic approach.

Elevation of the glycoxidation product N(epsilon)-(carboxymethyl)lysine in patients presenting with acute myocardial infarction

BACKGROUND

An important role in the acceleration of vascular disease has been previously suggested for advanced glycation end products. N(epsilon)-(carboxymethyl)lysine (CML) is an advanced glycation end product formed on protein by combined non-enzymatic glycation and glycoxidation reactions. CML reacts with the receptor of advanced glycation end products inducing impairment of endothelium dependent relaxation and is a marker of oxidative stress.

METHODS

A total of 40 patients with acute myocardial infarction (17 patients with ST-elevation myocardial infarction, 23 patients with non-ST-elevation myocardial infarction) and 40 patients with stable coronary artery disease were included consecutively in this study. During coronary angiography, peripheral venous blood sample was taken for measuring CML.

RESULTS

Serum levels of CML were significantly increased in patients with acute myocardial infarction [17.9+/-10.7 vs. 6.6+/-3.1 arbitrary units (AU)/mg protein, p<0.001]. A cut-off value of CML>9.5 AU/mg protein was associated with an odds ratio of acute myocardial infarction of 39.7 [95% confidence interval (CI): 11.1-142, p<0.001], a sensitivity of 0.85 (95% CI: 0.70-0.94) and a specificity of 0.88 (95% CI: 0.73-0.96).

CONCLUSIONS

CML levels are significantly elevated in patients presenting with acute myocardial infarction. These results suggest the involvement of endothelial dysfunction (through receptor interaction) and oxidative stress in acute myocardial infarction.

CagA antigen of Helicobacter pylori and coronary instability: insight from a clinico-pathological study and a meta-analysis of 4241 cases

BACKGROUND

Cytotoxin-associated gene-A (CagA) antigen is expressed by some virulent strains of Helicobacter pylori (H. pylori). The role of CagA antigen in coronary instability is unknown. We performed a clinico-pathological study and a meta-analysis in the attempt to shed new light on this complex issue.

METHODS

In the clinico-pathological study, 38 patients with unstable angina (UA), 25 patients with stable angina (SA), 21 patients with normal coronary arteries (NCA) and 50 age and sex matched healthy volunteers were enrolled. Serology for CagA was assessed in all patients. Specimens of atherosclerotic plaques were obtained from all patients by directional coronary atherectomy, and prepared for immunohistochemistry using anti-CagA monoclonal antibodies. The meta-analysis includes 9 studies assessing the association between seropositivity to CagA strains and acute coronary events.

RESULTS

The titre of anti-CagA antibodies was significantly higher in patients with unstable angina (161+/-90 RU/ml) compared to those with stable angina (83+/-59 RU/ml p<0.02), NCA (47.3+/-29 RU/ml p<0.01) and healthy controls (73+/-69 p<0.02). Anti-CagA antibodies recognized antigens localized inside coronary atherosclerotic plaques in all specimens from both stable and unstable patients. In the meta-analysis, seropositivity to CagA was significantly associated with the occurrence of acute coronary events with an odds ratio (OR) of 1.34 (95% CI, 1.15-1.58, p=0.0003).

CONCLUSIONS

Taken together these findings suggest that in a subset of patients with unstable angina, an intense immune response against CagA-positive H. pylori strains might be critical to precipitate coronary instability mediated by antigen mimicry between CagA antigen and a protein contained in coronary atherosclerotic plaques.

Prevalence of hypoechoic carotid plaques in coronary artery disease: relationship with coexistent peripheral arterial disease and leukocyte number

Abstract

In coronary artery disease (CAD), a concomitant peripheral arterial disease (PAD) entails a more severe coronary atherosclerosis. We hypothesized that the severity of carotid artery disease is greater in CAD+PAD than in CAD alone. In 90 CAD and 79 CAD+PAD patients, carotid plaque echolucency was measured by gray-scale median (GSM), and the degree of carotid stenosis by routine Doppler criteria. Plaques were absent in 20 (22.2%) CAD and 8 (10.1%) CAD+PAD patients ( p = 0.035), while the prevalence of carotid stenosis ≥ 50% was 16.7% and 25.3%, respectively ( p = 0.166). The GSM score was 45.1 [21.7–67.7] in CAD+PAD vs 60.1 [44.9–83.1] in CAD alone ( p < 0.001). Consistently, hypoechoic plaques (GSM < 25th percentile) were more common in CAD+PAD than in CAD patients (38.0% vs 11.4%, p < 0.001). On multivariate analysis, CAD+PAD was the only variable significantly associated with hypoechoic plaques (OR = 4.16, 95% CI 1.68–10.28). However, when the leukocyte count was added to the model, it showed the strongest association with hypoechoic plaques (OR = 6.70, 95% CI 2.13–21.10). In conclusion, compared with CAD alone patients, those with concomitant PAD showed a greater prevalence of plaques with characteristics of instability. Thus, our data suggest that in CAD+PAD, evaluation of carotid plaque echogenicity could contribute to improve clinical decision-making and differentiate treatments for individual patients.

A novel peptide agonist of formyl-peptide receptor-like 1 (ALX) displays anti-inflammatory and cardioprotective effects

Activation of the formyl-peptide receptor-like (FPRL) 1 pathway has recently gained high recognition for its significance in therapy of inflammatory diseases. Agonism at FPRL1 affords a beneficial effect in animal models of acute inflammatory conditions, as well as in chronic inflammatory diseases. TIPMFVPESTSKLQKFTSWFM-amide (CGEN-855A) is a novel 21-amino acid peptide agonist for FPRL1 and also activates FPRL2. CGEN-855A was discovered using a computational platform designed to predict novel G protein-coupled receptor peptide agonists cleaved from secreted proteins by convertase proteolysis. In vivo, CGEN-855A displays anti-inflammatory activity manifested as 50% inhibition of polymorphonuclear neutrophil (PMN) recruitment to inflamed air pouch and provides protection against ischemia-reperfusion-mediated injury to the myocardium in both murine and rat models (36 and 25% reduction in infarct size, respectively). Both these activities are accompanied by inhibition of PMN recruitment to the injured organ. The secretion of inflammatory cytokines, including interleukin (IL)-6, IL-1beta, and tumor necrosis factor-alpha, was not affected upon incubation of human peripheral blood mononuclear cells with CGEN-855A, whereas IL-8 secretion was elevated up to 2-fold upon treatment with the highest CGEN-855A dose only. Collectively, these new data support a potential role for CGEN-855A in the treatment of reperfusion-mediated injury and in other acute and chronic inflammatory conditions.

Multifocal, persistent cardiac uptake of [18-F]-fluoro-deoxy-glucose detected by positron emission tomography in patients with acute myocardial infarction

BACKGROUND

Inflammation appears to be important in the pathogenesis of acute myocardial infarction (AMI).

METHODS AND RESULTS

Cardiac [18-F]-fluoro-deoxy-glucose (FDG) uptake by positron emission tomography/computed tomography (PET/CT)-scan was investigated in 12 fasting patients with first AMI (FAMI) single-vessel disease after successful primary percutaneous coronary intervention and at 9 weeks follow-up, and in 12 controls. The average FDG uptake (aFDGu) of the 28 left ventricular (LV) wall segments defined on the PET/CT images of the 12 FAMI patients was 1.28+/-0.57-fold higher than the activity present in the LV cavity. By contrast, the aFDGu of the 12 controls was 0.70+/-22 (p<0.001). The segmental aFDGu in the FAMI was multifocal in both the culprit and non-culprit segments; it was less than LV cavity activity in 38%, 1-2-fold greater in 51.8% and more than 2-fold greater in 10.2%. At follow-up, aFDGu was significantly increased in both culprit and non-culprit segments (1.69+/-1.15, p<0.001). Statistically significant differences between FAMI and controls patients were only found for interleukin-6 plasma levels on admission (11.3+/-7.7 pg/ml vs 2.2+/-1.3 pg/ml; p<0.004).

CONCLUSION

Multifocal, non-infarct related, cardiac-FDG-uptake occurred immediately after AMI and persisted at follow-up. The cause of these striking and consistent findings is still speculative.

Local and Systemic Mechanisms of Plaque Rupture

Mechanisms at the basis of coronary plaque instability are still elusive. On the one hand, accumulating data, from clinical and postmortem studies, suggest the role of systemic factors, in particular inflammation, in plaque rupture. On the other hand, local factors, in particular plaque composition, such as a large lipid-rich core and a thin fibrous cap, presence of activated inflammatory cells, presence of plaque neovascularization, and specific apoptotic processes, may contribute to plaque susceptibility to rupture. In addition, other cofactors, such as platelet activation and clotting factors, are involved in the transition from stable to unstable plaque. The authors discuss the possibility that all these factors have a role in the development of acute coronary syndrome: a systemic inflammatory condition with an enhanced coagulation state may activate local hemodynamic, mechanical, and immune reactions leading to intraplaque cells activation, fibrous cap lysis, and thrombus formation.

Mild inflammatory activation of mammary arteries in patients with acute coronary syndromes

Acute coronary syndromes (ACS) are characterized by multiple unstable coronary plaques and elevated circulating levels of inflammatory biomarkers. The endothelium of internal mammary arteries (IMA), which are atherosclerosis resistant, is exposed to proinflammatory stimuli as vessels that develop atherosclerosis. Our study investigated the IMA endothelial expression of inflammatory molecules in patients with ACS or chronic stable angina (CSA). IMA demonstrated normal morphology, intact endothelial lining, and strong immunoreactivity for glucose transporter 1. E-selectin expression was observed more frequently in IMA of ACS patiention than CSA patients (ACS 61% vs. CSA 14%, P = 0.01). High fluorescence for major histocompatibility complex (MHC) was significantly more frequent on the luminal endothelium (ACS 66.7% vs. CSA 17.6%, P = 0.001 for class I; and ACS 66.7% vs. CSA 6.2%, P = 0.0003 for class II-DR) and on the vasa vasorum (ACS 92.9% vs. CSA 33.3% and 7.7%, P = 0.0007 and P < 0.0001 for class I and class II-DR, respectively) of ACS patients than CSA patients. ICAM-1, VCAM-1, Toll-like receptor 4, tissue factor, IL-6, inducible nitric oxide synthase, and TNF-alpha expression were not significantly different in ACS and CSA. Circulating C-reactive protein [ACS 4.8 (2.6-7.3) mg/l vs. CSA 1.8 (0.6-3.5) mg/l, P = 0.01] and IL-6 [ACS 4.0 (2.6-5.5) pg/ml vs. CSA 1.7 (1.4-4.0) pg/ml, P = 0.02] were higher in ACS than CSA, without a correlation with IMA inflammation. The higher E-selectin, MHC class I and MHC class II-DR on the endothelium and vasa vasorum of IMA from ACS patients suggests a mild, endothelial inflammatory activation in ACS, which can be unrelated to the presence of atherosclerotic coronary lesions. These findings indicated IMA as active vessels in coronary syndromes.

Comparison of the inflammatory burden of truly asymptomatic carotid atheroma with atherosclerotic plaques in patients with asymptomatic carotid stenosis undergoing coronary artery bypass grafting: an ultrasmall superparamagnetic iron oxide enhanced magnetic resonance study

INTRODUCTION

Inflammation is a recognized risk factor for the vulnerable atherosclerotic plaque. The aim of this study was to explore whether there is a difference in the degree of Magnetic Resonance (MR) defined inflammation using Ultra Small Super-Paramagnetic Iron Oxide (USPIO) particles, within carotid atheroma in completely asymptomatic individuals and the asymptomatic carotid stenosis in a cohort of patients undergoing coronary artery bypass grafting (CABG).

METHODS

10 patients awaiting CABG with asymptomatic carotid disease and 10 completely asymptomatic individuals with no documented coronary artery disease underwent multi-sequence MR imaging before and 36 hours post USPIO infusion. Images were manually segmented into quadrants and signal change in each quadrant, normalised to adjacent muscle signal, was calculated following USPIO administration.

RESULTS

The mean percentage of quadrants showing signal loss was 94% in the CABG group, compared to 24% in the completely asymptomatic individuals (p<0.001). The carotid plaques from the CABG patients showed a significant mean signal intensity decrease of 16.4% after USPIO infusion (95% CI 10.6% to 22.2%; p<0.001). The truly asymptomatic plaques showed a mean signal intensity increase (i.e. enhancement) after USPIO infusion of 8.4% (95% CI 2.6% to 14.2%; p=0.007). The mean signal difference between the two groups was 24.9% (95% CI 16.7% to 33.0%; p<0.001).

CONCLUSIONS

These findings are consistent with the hypothesis that inflammatory atheroma is a systemic disease. The carotid territory is more likely to take up USPIO if another vascular territory is symptomatic.

A sensitive assay for the quantification of integrin-mediated adhesiveness of human stem cells and leukocyte subpopulations in whole blood

Adhesion of leukocytes is an early step in the formation of adaptive or innate immunity. In chronic inflammatory pathologies like atherosclerosis, regulation of adhesiveness is pivotal for the accumulation of leukocytes within the vessel wall. Therefore, the quantification of adhesion is crucial for the understanding and monitoring of immune responses in patients. However, so far, functional analysis of leukocyte adhesion has been time consuming and required prior purification of cell populations from peripheral blood. This reduced the number of samples and cell populations that could be analysed from limited patient material. Here, we introduce a novel method involving rapid quantification of integrin-mediated leukocyte adhesion in human whole blood using flow cytometry. The quantification relies on soluble multivalent immunocomplexes and is thus called "ligand-complex-based adhesion assay" (LC-AA). LC-AA evaluates both integrin affinity and avidity in T-cells, NK-cells and monocytes from as little as 20 mul of whole blood. In marked contrast to T-cells and NK-cells, unstimulated monocytes show non-blockable background binding of the complexes. Therefore, for this subset only, the stimulation-induced integrin activation is measurable. With the LC-AA, for the first time, measurement of adhesiveness of extremely rare cell populations like CD34+ peripheral blood stem cells can be assessed in the absence of prior purification steps. Finally, the small blood volumes needed for adhesion analysis with the LC-AA allow the evaluation of multiple cell subpopulations in large sample collectives, e.g. required in clinical studies.

Pregnancy associated plasma protein-A and risk stratification of patients presenting with chest pain in the emergency department

BACKGROUND

The aim of this study was to evaluate the clinical utility of serum pregnancy associated plasma protein-A (PAPP-A) levels in assisting triage of an intermediate to high-risk patient presenting with chest pain in the Emergency Department and no definite evidence of an acute coronary syndrome.

METHODS

Serum levels of PAPP-A were measured in 59 patients presenting with chest pain to the Emergency Department. The patients were independently grouped according to the presence of acute coronary syndromes or the absence thereof.

RESULTS

In a multivariate model that corrected for age, sex, type of chest pain, number of risk factors, history of coronary artery disease, troponin levels, and non-specific ECG changes, PAPP-A levels were still predictive of a final diagnosis of acute coronary syndrome in patients presenting with chest pain to the Emergency Department (Odds Ratio, 2.093; 95th confidence intervals, 1.037-4.224; p=0.039).

CONCLUSIONS

Elevated serum PAPP-A levels were predictive of a diagnosis of acute coronary syndrome in intermediate- to high-risk patients presenting to the Emergency Department with chest pain and no definite evidence of an acute coronary syndrome. Thus, serum PAPP-A may be valuable as an adjunct, minimally invasive marker to improve risk stratification in chest pain patients.

Persistent Chlamydia pneumoniae infection of cardiomyocytes is correlated with fatal myocardial infarction

Acute myocardial infarction (AMI) associated with unfavorable prognosis is likely to be the consequence of a diffuse active chronic inflammatory process that destabilizes the whole coronary tree and myocardium, suggesting a possible common causal agent underlying both conditions. The main objective of this study was to investigate whether Chlamydia pneumoniae (CP) infection occurred beyond the coronary plaques, namely in the myocardium of individuals who died of AMI. The presence of CP cell wall antigen (OMP-2) and CP-HSP60 was investigated in the myocardium and coronary plaques of 10 AMI and 10 age-matched control patients by immunohistochemistry, electron microscopy, and molecular biology. OMP-2 antigens were found in the unaffected myocardium of 9 of 10 AMI patients. Conversely, only 1 of 10 control patients exhibited a positive staining for CP. Moreover, OMP-2 and CP-HSP60 were detected in the whole coronary tree. CP presence was strongly associated with a T-cell inflammatory infiltrate. Our results suggest that CP may underlie both coronary and myocardial vulnerabilities in patients who died of AMI and corroborate the notion that CP may act by reducing cardiac reserves, thus worsening the ischemic burden of myocardium.

Plaque vulnerability and related coronary event prediction by intravascular ultrasound with virtual histology: “It's a long way to tipperary”?

Identification of so-called "vulnerable plaque" or "high-risk" plaques have spawned manifold attempts to develop diagnostic tools capable to afford this task. This task is particularly challenging but the reward is high: local intervention on identified "vulnerable plaque" could preclude plaque thrombosis and possibly prevent acute coronary syndromes. Various imaging techniques are currently under investigation by extensive clinical testing to identify which could become the most sensible and specific modality for vulnerable plaque detection. Noninvasive techniques are fascinating for their easily applicability to a broad population but nowadays are not sufficiently powered for this task. The emerging technologies with the greatest resolution are indeed catheter-based and many intravascular modalities have been developed for identification of "vulnerable plaque". Among these, IVUS-Virtual Histology (IVUS-VH) is the most promising technique in the field. IVUS-VH offers an in vivo opportunity to assess plaque morphology and histology. IVUS-VH uses underlying frequency information along with echoes intensity, while grey-scale IVUS data are obtained from echoes of different intensity or amplitude. The major advantage of IVUS-VH is that it is based on a device that is practical for use in the clinical setting and that it generates a real-time assessment of plaque morphology. Unfortunately, numerous challenging issues still need to be overcome until the numerous "vulnerable plaques" could be identified and successfully treated. Future efforts may identify plaques that are on a trajectory of evolution toward a vulnerable state, and help us target interventions to those plaques most likely to develop plaque disruption and related complications.

Atherosclerosis: disease biology affecting the coronary vasculature

The concept of the vulnerable plaque has generated much interest and stimulated a quest to develop diagnostic modalities to identify potentially unstable atherosclerotic plaques. However, accumulating clinical data now suggest that multiple vulnerable plaques coexist in a single coronary tree and that inflammation is a critical determinant of the stability of plaques. Inflammatory mediators, such as cytokines, can influence several biologic processes that regulate stability of the plaque's fibrous cap and its resistance to rupture. Thus, the quest for strategies to identify and target treatment to a single culprit lesion seriously underestimates the complexity of the clinical biology of thrombosis in atherosclerotic arteries. For the optimum management of our patients, we must now also consider the vulnerable artery, the vulnerable arterial bed, and ultimately, the vulnerable patient. Treatment of vulnerable patients should include measures to stabilize plaques and to lessen the thrombotic consequences of plaque disruptions.

What are the most useful and trustworthy noninvasive anatomic markers of existing vascular disease?

Cardiovascular disease is the leading cause of mortality and morbidity in developed countries. Evidence challenges the notion that the severity of lesions on angiography is a predictor of future cardiac events. With the recognition that subclinical coronary artery stenoses are responsible for myocardial infarcts and sudden death, it may be important to identify patients with plaque characteristics that may place them at increased risk. Intravascular ultrasound, though invasive, remains the current imaging gold standard. Computed tomography, cardiac magnetic resonance, and single-photon emission CT positron emission tomography are evolving and promising modalities. Functional studies reflecting plaque temperature and molecular imaging reflecting plaque constituents are being developed. We review the pathology of the vulnerable atherosclerotic plaque and recent innovations in imaging modalities to assess plaque complication risk.

Review article: The role of statins in reducing perioperative cardiac risk: physiologic and clinical perspectives

PURPOSE

To review the pathobiology and clinical implications of coronary vulnerable atherosclerotic plaques (VAPs), to discuss the role of statin therapy in VAP stabilization, and the potential benefits of perioperative statin therapy (PST) in reducing perioperative risk of acute coronary syndromes (ACSs).

SOURCE

MEDLINE search using "perioperative", "cardiac morbidity", "atherosclerosis", "vulnerable plaque", "statins" and combinations of these terms as keywords. The reference lists of relevant articles were further reviewed to identify additional citations.

PRINCIPAL FINDINGS

The nonstenotic, yet rupture-prone VAP causes most myocardial infarctions (MIs) and other ACSs, both in the nonsurgical and surgical patients. Large clinical trials in both primary and secondary prevention and in patients with ACSs have demonstrated that statin therapy will reduce cardiovascular morbidity and mortality across a broad spectrum of patient subgroups. These trials also suggest, and laboratory investigations establish, that statins possess favourable vascular effects independent of cholesterol reduction. Statins appear to interfere specifically with the pathophysiologic mechanisms implicated in atherothrombotic disease. Statins reduce vascular inflammation, improve endothelial function, stabilize VAPs, and reduce platelet aggregability and thrombus formation. Recent studies have shown that PST is associated with a reduced incidence of perioperative and long-term cardiovascular complications in high-risk patients. Combined therapy with statins and ss-blockers is a conceptually valid strategy targeting critical steps in the pathogenesis of an ACS.

CONCLUSION

Emerging evidence for the efficacy and safety of PST is promising, especially when combined with ss-blocker therapy in patients at highest risk. Confirmation of this early evidence awaits the results of ongoing and future prospective randomized controlled trials.

Radionuclide imaging for the detection of inflammation in vulnerable plaques

Imaging of atheromatous plaques has traditionally centered on assessing the degree of luminal stenosis. More recently it has become clear that the vulnerable atherosclerotic plaques responsible for the majority of life-threatening syndromes are characterized by high numbers of inflammatory cells and proteins. This has highlighted the urgent need for suitable imaging techniques that can identify and quantify levels of inflammation within atheromatous lesions. Positron emission tomography and single-photon emission computed tomography imaging hold promise in this regard. Tracer compounds capable of assessing macrophage recruitment, foam cell generation, matrix metalloproteinase production, macrophage apoptosis, and macrophage metabolism have been developed and tested in the carotid and peripheral circulation. The identification of inflamed lesions within the coronary circulation, however, remains elusive owing to small plaque size, cardiac and respiratory motion, and lack of a suitable specific nuclear tracer.

Increased coronary sinus blood temperature: correlation with systemic inflammation

BACKGROUND

Recent studies have shown that patients with single vessel coronary artery disease (CAD) suffering from acute coronary syndromes (ACS) have increased coronary sinus (CS) blood temperature compared with the right atrium (RA). The aim of this study was to investigate whether there is a correlation between systemic inflammatory indexes and CS temperature and whether there is a difference in CS temperature between patients with single vs. multivessel disease. MATERIALS AND METHODS We included consecutive patients scheduled for coronary angiography for recent-onset chest pain evaluation. We measured C-reactive protein (CRP) levels in the study population. Coronary sinus and RA blood temperature measurements were performed by a 7F thermography catheter. DeltaTau was calculated by subtracting the RA from the CS blood temperature.

RESULTS

The study population comprised 53 patients with ACS, 25 patients with stable angina (SA) and 22 subjects without CAD (control group). DeltaTau was greater in patients with ACS and with SA compared with the control group (0.22 +/- 0.10 degrees C, 0.18 +/- 0.04 degrees C vs. 0.14 +/- 0.07 degrees C, P < 0.01 for both comparisons). The ACS group had greater DeltaTau compared with the SA group, although the difference did not reach statistical significance (P = 0.09). Eighteen (39.1%) out of 46 patients with multivessel disease had three-vessel disease and 28 (60.8%) had two-vessel disease. DeltaTau between patients with multivessel and single vessel disease was similar (0.22 +/- 0.01 degrees C, 0.19 +/- 0.01 degrees C, P = 0.17). The levels of CRP were well correlated with DeltaTau (R = 0.35b, P < 0.01).

CONCLUSIONS

Systemic inflammation is well correlated with CS temperature; thus, an inflammatory process could be the underlying mechanism for increased heat production from the myocardium.

Intracoronary thermography: does it help us in clinical decision making?

The concept of the "vulnerable" plaque has recently emerged to explain how quiescent atherosclerotic lesions evolve to cause clinical events. The morphologic and immunologic determinants specific for the vulnerable plaque have been reported: a large lipid core (>or=40% plaque volume) composed of free cholesterol crystals, cholesterol esters, and oxidized lipids impregnated with tissue factor; a thin fibrous cap depleted of smooth muscle cells and collagen; an outward (positive) remodeling; inflammatory cell infiltration of fibrous cap and adventitia (mostly monocyte-macrophages, some activated T cells, and mast cells); and increased neovascularity. Despite the large amount of information regarding the morphological characteristics of remote lesions, we lack studies with functional assessment of non-culprit lesions. Coronary thermography is a technique for functional assessment of coronary atherosclerotic plaques. Several catheter designs have been proposed. There are catheters with thermistor(s) and wires with thermal sensors at the distal tip. All designs have several advantages and disadvantages. Despite the current limitations of coronary thermography, we gained important pathophysiological and clinical information regarding the vulnerability of atheromatic plaques. It has been documented both experimentally and clinically that increased heat generation is associated with increased macrophage concentration within the plaque. The correlation between local inflammatory involvement and local heat generation has also been observed with the peripheral inflammatory markers such as C-reactive protein. Whether systemic treatment, with agents such as statins or interventional techniques, such as drug-eluting stents, will have an impact on stabilizing vulnerable plaques need to be determined in future studies. In conclusion, although there are several techniques for evaluating morphologically atheromatic plaques, thermography is a promising method for the functional assessment of vulnerable plaque and has been introduced into clinical practice, with a good predictive value for clinical events in patients with increased temperature in the atherosclerotic plaque.