Vulnerable and dangerous coronary plaques

Impact of Intravascular Imaging-Guided Stent Optimization According to Clinical Presentation in Patients Undergoing Complex PCI

BACKGROUND

It is unclear whether the beneficial effects of intravascular imaging-guided stent optimization vary by clinical presentation during complex percutaneous coronary intervention (PCI).

OBJECTIVES

In this prespecified, stratified subgroup analysis from RENOVATE-COMPLEX-PCI (Randomized Controlled Trial of Intravascular Imaging Guidance versus Angiography-Guidance on Clinical Outcomes After Complex PCI), we sought to compare the outcomes between intravascular imaging vs angiography guidance according to clinical presentation.

METHODS

Patients with complex coronary artery lesions were randomly assigned to undergo either intravascular imaging-guided PCI or angiography-guided PCI in a 2:1 ratio. The primary endpoint was target vessel failure (TVF), which is a composite of cardiac death, target vessel-related myocardial infarction, or clinically driven target vessel revascularization.

RESULTS

Of 1,639 patients, 832 (50.8%) presented with acute coronary syndrome (ACS) and 807 (49.2%) with chronic coronary syndrome. During a median follow-up of 2.1 years (Q1-Q3: 1.4-3.0 years), there was no significant interaction between the treatment effect of intravascular imaging and clinical presentation (P for interaction = 0.19). Among patients with ACS, the incidences of TVF were 10.4% in the intravascular imaging group and 14.6% in the angiography group (HR: 0.74; 95% CI: 0.48-1.15; P = 0.18). Among patients with CCS, the incidences of TVF were 5.0% in the intravascular imaging group and 10.4% in the angiography group (HR: 0.46; 95% CI: 0.27-0.80; P = 0.006). Achieving stent optimization by intravascular imaging resulted in a reduced risk of TVF among patients with ACS who were randomly assigned to intravascular imaging-guided PCI for complex coronary lesions (optimized vs unoptimized, 6.5% vs 14.1%; HR: 0.49; 95% CI: 0.27-0.87; P = 0.02) but not those with CCS (5.4% vs 4.7%, HR: 1.18; 95% CI: 0.53-2.59; P = 0.69).

CONCLUSIONS

No significant interaction was observed between the benefits of intravascular imaging and clinical presentation in the risk of TVF. Stent optimization by intravascular imaging was particularly important for ACS patients. (Intravascular Imaging- Versus Angiography-Guided Percutaneous Coronary Intervention For Complex Coronary Artery Disease [RENOVATE]; NCT03381872).

ANMCO POSITION PAPER: Prognostic and therapeutic relevance of non-obstructive coronary atherosclerosis

Atherosclerosis often affects the coronary arterial tree. Frequently the disease does not translate in significant narrowing of the vessels, thus determining only a non-obstructive disease. This condition that is described as non-obstructive coronary artery disease (NobsCAD) should be distinguished from the absence of disease (i.e. smooth coronary arteries) as it carries a specific prognostic value. The detection and reporting of NobsCAD should prompt preventive measures that can be individualized upon the degree of the underlying burden of disease. The accompanying clinical condition, the other cardiovascular risk factors present, and the description of the severity and extent of NobsCAD should provide the framework for an individualized treatment that should also consider the best available scientific evidence and guidelines. The description of NobsCAD represents important information to be collected whenever a coronary angiogram (both invasive and non-invasive) is performed. Treating the patient according to the presence and extent of NobsCAD offers prognostic benefits well beyond those offered by considering only the traditional cardiovascular risk factors. In order to reach this goal, NobsCAD should not be confused with the absence of coronary atherosclerosis or even ignored when detected as if it was a trivial information to provide.

Gd(DOTA)-grafted submicronic polysaccharide-based particles functionalized with fucoidan as potential MR contrast agent able to target human activated platelets

Early detection of thrombotic events remains a big medical challenge. Dextran-based submicronic particles bearing Gd(DOTA) groups and functionalized with fucoidan have been produced via a simple and green water-in-oil emulsification/co-crosslinking process. Their capacity to bind to human activated platelets was evidenced in vitro as well as their cytocompatibility with human endothelial cells. The presence of Gd(DOTA) moieties was confirmed by elemental analysis and total reflection X-ray fluorescence (TRXF) spectrometry. Detailed characterization of particles was performed in terms of size distribution, morphology, and relaxation rates. In particular, longitudinal and transversal proton relaxivities were respectively 1.7 and 5.0 times higher than those of DOTAREM. This study highlights their potential as an MRI diagnostic platform for atherothrombosis.

Combination of tanshinone IIA and astragaloside IV attenuate atherosclerotic plaque vulnerability in ApoE(-/-) mice by activating PI3K/AKT signaling and suppressing TRL4/NF-κB signaling

Tanshinone IIA (TS IIA) and Astragaloside IV (AS IV) are natural herbal products which exert anti-inflammatory and anti-oxidant effects in order to eliminate unstable plaque in atherosclerosis. However, the combined effect of these two drugs on atherosclerotic plaque vulnerability and its molecular mechanism remains unclear. In the current study, we evaluate the effects of TS IIA and AS IV on atherosclerotic unstable plaque stability, and then further explore the mechanism of TS IIA and AS IV intervention on unstable plaque in vivo and in vitro. Histological characterization of atherosclerotic plaques was measured by Hematoxylin-Eosin (HE), Masson's Trichrome and Oil Red O staining. Cellular lipid droplet was measured by Oil Red O staining. The size of atherosclerotic lesion areas and content of lipids and collagen in the right common carotid arteries of apoE-/- mice were examined by Hematoxylin-Eosin (HE), Oil-red O, and Masson staining, respectively. The protein expression levels of interleukin (IL)-6, tumor necrosis factor (TNF)-α and C-reactive protein (CRP) in ApoE^-/- mice and RAW264.7 cells were determined by enzyme-linked immunosorbent assay. The protein expression levels of matrix metalloproteinase-9 (MMP-9) and endothelial nitric oxide synthase (eNOS) in ApoE^-/- mice and RAW264.7 cells were determined by western blotting. In addition, the PI3K/AKT and TRL4/NF-κB signaling were determined by western blotting. Our results revealed that the combination of TS IIA and AS IV significantly decreased lipid areas, increased collagen content and thickened fibrous cap in the right common carotid arteries compared with ApoE (-/-) mice model group. TS IIA and AS IV visibly reduced the cytoplasmic lipid droplet accumulation induced by oxLDL in RAW 264.7 macrophages. The ApoE^-/- mice model group and oxLDL -stimulated RAW 264.7 macrophages treated with TS IIA and AS IV showed a downregulation in IL-6, MMP-9, TNF-α and CRP protein expression and upregulation in eNOS protein expression. Furthermore, TSIIA and AS IV may activate PI3K/AKT signaling and suppress TLR4/NF-κB signaling in vivo and in vitro. Additionally, blocking the PI3K/Akt signaling enhanced the translocation of NF-κB to the nucleus, TLR4, IL-6, MMP-9, TNF-α and CRP expression and inhibited eNOS expression in TS IIA and AS IV-treated RAW 264.7 macrophages. Therefore, the present study implicates that TS IIA and AS IV reinforces plaque stability via PI3K/AKT and TLR4/NF-κB signaling. TS IIA and AS IV administration may provide the basis for a potential therapeutic approach for the inhibition of vulnerable atherosclerotic plaques.

Apelin-13 treatment enhances the stability of atherosclerotic plaques

BACKGROUND

Apelin is an endogenous peptidergic system which modulates cardiovascular function. Recent studies pointed out a fundamental contribution of apelin on atherosclerosis development; however, such reports revealed contradictory data, and to date, it is difficult to accurately define a beneficial or deleterious role. To better understand apelin function on atherosclerosis, we aimed to investigate apelin-13 treatment effects on atherosclerotic plaques composition.

DESIGN

Apolipoprotein E gene-deleted mice were fed on Western-type diet for 11 weeks. Atherosclerotic plaque formation was induced in the carotid artery by a shear stress modifier device, which exposes the same vessel to distinct patterns of shear stress enabling the formation of plaques with different composition. Mice were treated with apelin-13 (2 mg kg^-1 day^-1 ) or vehicle for the last 3 weeks.

RESULTS

Apelin-13 treatment did not alter the lipid content of low shear stress- and oscillatory shear stress-induced plaques in the carotid. However, apelin-13 greatly ameliorated plaque stability by increasing intraplaque collagen content and reducing MMP-9 expression. Furthermore, apelin-13 decreased the infiltration of inflammatory cells (neutrophil and macrophage) and intraplaque reactive oxygen species content. Interestingly, apelin-13 treatment reduced total cholesterol, LDL levels and free fatty acid serum levels, while HDL, triglycerides serum levels were not significantly changed.

CONCLUSIONS

Apelin-13 treatment for 3 weeks did not alter the lesion size, but it significantly enhanced the stable phenotype of atherosclerotic plaques and improved serum lipid profile. These results indicate that activation of apelin system decreases plaque vulnerability.

Carotid Artery Wall Imaging: Perspective and Guidelines from the ASNR Vessel Wall Imaging Study Group and Expert Consensus Recommendations of the American Society of Neuroradiology

Identification of carotid artery atherosclerosis is conventionally based on measurements of luminal stenosis and surface irregularities using in vivo imaging techniques including sonography, CT and MR angiography, and digital subtraction angiography. However, histopathologic studies demonstrate considerable differences between plaques with identical degrees of stenosis and indicate that certain plaque features are associated with increased risk for ischemic events. The ability to look beyond the lumen using highly developed vessel wall imaging methods to identify plaque vulnerable to disruption has prompted an active debate as to whether a paradigm shift is needed to move away from relying on measurements of luminal stenosis for gauging the risk of ischemic injury. Further evaluation in randomized clinical trials will help to better define the exact role of plaque imaging in clinical decision-making. However, current carotid vessel wall imaging techniques can be informative. The goal of this article is to present the perspective of the ASNR Vessel Wall Imaging Study Group as it relates to the current status of arterial wall imaging in carotid artery disease.

Serum lipoprotein-associated phospholipase A2 predicts the formation of carotid artery plaque and its vulnerability in anterior circulation cerebral infarction

OBJECTIVE

Circulation inflammation markers such as high-sensitive C-reactive protein (hsCRP) and lipoprotein-associated phospholipase A2 (Lp-PLA2) are considered as predictors of cerebral and cardiac vascular diseases. However, the role of hsCRP and Lp-PLA2 in the anterior circulation cerebral infarction (ACI) is to be elaborated.

PATIENTS AND METHODS

We included 100 patients with acute anterior circulation cerebral infarction (AaCI group) and 50 non-infarction subjects (control group). Carotid artery was detected by color Doppler ultrasound. Subjects were grouped based on carotid intima-media thickness (IMT) and degree of stability of carotid atherosclerotic plaque. The levels of hsCRP and Lp-PLA2 were measured in corresponding groups and the association was analyzed.

RESULTS

hsCRP and Lp-PLA2 levels were the risk factors for AaCI. With the increment of carotid IMT and degree of plaque instability, the level of hsCRP and Lp-PLA2 showed an elevating tendency. hsCRP and Lp-PLA2 levels were significantly higher in plaque formation group than in IMT normal group (P=0.002 and P=0.001, respectively). hsCRP and Lp-PLA2 levels were significantly higher in vulnerable plaque group than in mixed plaque group and stable plaque group (P=0.003, P<0.001 for hsCRP and P<0.001, P<0.001 for Lp-PLA2). Lp-PLA2 was finally included in the atherosclerotic plaque model (OR=1.019, 95% confidence interval (CI): 1.003-1.035, P=0.020) and vulnerable plaque model (OR=1.041, 95%CI: 1.017-1.065, P=0.001) by performing multivariate logistic regression analysis. The area under the ROC curve (AUC) of Lp-PLA2 levels for atherosclerotic plaque was 0.746 (95% CI: 0.628-0.865, P<0.001). The optimal cut-off value for Lp-PLA2 level was 267.5ng/ml, and its sensitivity and specificity for diagnosis of atherosclerotic plaque were 70.8% and 67.1%, respectively.

CONCLUSIONS

The current study demonstrates that hsCRP and Lp-PLA2 are among the risk factors for AaCI. Elevated hsCRP and Lp-PLA2 are associated with carotid plaque formation. Univariate and multivariate logistic regression analysis suggests that elevated Lp-PLA2 is the independent risk factor for carotid plaque and its vulnerability.

Ligustrazine for the Treatment of Unstable Angina: A Meta-Analysis of 16 Randomized Controlled Trials

Ligustrazine is a principal ingredient of chuanxiong. Concerns regarding the evaluation of the effectiveness of ligustrazine in the treatment of UA have resulted in a meta-analysis combined with recent clinical evidence. Seven computer databases that included the China hospital knowledge database (CHKD), Wanfang Med Online, the Chinese medical journal database (CMJD), PubMed, Cochrane, Embase (Ovid), and Medline (Ovid) were systematically searched. We included randomized controlled trials and quasi-randomized controlled trials. Our systematic review identified 16 RCTs that met our eligibility criteria. Ligustrazine combined with conventional medicine was associated with an increased rate of marked improvement in symptoms and an increased rate of marked improvement of ECG compared with conventional Western medicine alone. Additionally, the use of ligustrazine was associated with significant trends in the reduction of the consumption of nitroglycerin and the level of fibrinogen when compared with conventional Western medicine alone. No firm results were found between the intervention and the control method groups in the reduction of the time of onset or the frequency of acute attack angina due to the high level of heterogeneity. In conclusion, our meta-analysis found that ligustrazine was associated with some benefits for people with unstable angina.

Diminazene enhances stability of atherosclerotic plaques in ApoE-deficient mice

Angiotensin (Ang) II contributes to the development of atherosclerosis, while Ang-(1-7) has atheroprotective actions. Accordingly, angiotensin-converting enzyme 2 (ACE2), which breaks-down Ang II and forms Ang-(1-7), has been suggested as a target against atherosclerosis. Here we investigated the actions of diminazene, a recently developed ACE2 activator compound, in a model of vulnerable atherosclerotic plaque. Atherosclerotic plaque formation was induced in the carotid artery of ApoE-deficient mice by a shear stress (SS) modifier device. The animals were treated with diminazene (15mg/kg/day) or vehicle. ACE2 was strongly expressed in the aortic root and low SS-induced carotid plaques, but poorly expressed in the oscillatory SS-induced carotid plaques. Diminazene treatment did not change the lesion size, but ameliorated the composition of aortic root and low SS-induced carotid plaques by increasing collagen content and decreasing both MMP-9 expression and macrophage infiltration. Interestingly, these beneficial effects were not observed in the oscillatory SS-induced plaque. Additionally, diminazene treatment decreased intraplaque ICAM-1 and VCAM-1 expression, circulating cytokine and chemokine levels and serum triglycerides. In summary, ACE2 was distinctively expressed in atherosclerotic plaques, which depends on the local pattern of shear stress. Moreover, diminazene treatment enhances the stability of atherosclerotic plaques.

Targeting Cholesterol Crystal-Induced Inflammation for the Secondary Prevention of Cardiovascular Disease

Cholesterol crystals are present in nascent and advanced atherosclerotic plaque. Under some conditions, they may enlarge and cause direct plaque trauma or trigger an inflammatory cascade that promotes the growth and instability of atherosclerotic plaque. Therapies that reduce the risk of cholesterol crystal formation or prevent the associated inflammatory response have the potential to improve the clinical outcome of patients with cardiovascular disease. Statins have pleiotropic effects that can reduce the size of the free cholesterol pool contained within atherosclerotic plaques and prevent the formation of cholesterol crystals. Colchicine prevents crystal-induced inflammation by virtue of its ability to inhibit macrophage and neutrophil function. Both statins and colchicine have been demonstrated to reduce the risk of cardiovascular events in patients with stable coronary disease. The efficacy of statins and colchicine for cardiovascular prevention supports the hypothesis that crystal-induced inflammation plays an integral role in the progression and instability of coronary disease. Inhibition of cholesterol crystal-induced inflammation offers a promising new target for the secondary prevention of cardiovascular disease.

The clinical implications of increased cyclophilin A levels in patients with acute coronary syndromes

BACKGROUND

Cyclophilin A is a secreted molecule that has a physiological and pathological role in cardiovascular diseases. However, limited information is available on the relationship between cyclophilin A concentration and acute coronary syndromes (ACS). We investigated whether cyclophilin A concentration is related to the stability of coronary atherosclerotic plaque in patients with ACS.

METHODS

This study included normal controls (n=50), patients with stable angina (SA) (n=60) and patients with ACS, including unstable angina (UA) (n=60) and acute myocardial infarction (AMI) (n=90). Serum soluble cyclophilin A, matrix metalloproteinase 9 (MMP-9), MMP-3 and C-reactive protein concentrations (CRP) were measured. All coronary stenosis were assessed by angiographic coronary stenosis morphology.

RESULTS

Serum cyclophilin A concentration in ACS (UA and AMI ) subjects were significantly higher than those in patients with SA and controls (p<0.05). Serum cyclophilin A correlated positively with serum MMP-3 and MMP-9 and CRP in ACS patients(r(1)=0.69, r(2)=0.52, r(3)=0.49 p<0.0001), but not in control. Furthermore, the increased cyclophilin A concentrations was associated with the number of complex coronary stenoses (r(1)=0.63, p<0.0001), but not smooth lesions or stenosis severity, in coronary artery disease patients. Logistic regression analysis also demonstrated that serum cyclophilin A concentration was an independent predictor factor for ACS( OR, 2.721, 95% CI 1.563-4.042, p=0.001).

CONCLUSION

Patients with ACS showed that increased concentrations of cyclophilin A may be a valuable marker for predicting the severity of ACS.

Intravascular optical imaging technology for investigating the coronary artery

There is an ever-increasing demand for new imaging methods that can provide additional information about the coronary wall to better characterize and stratify high-risk plaques, and to guide interventional and pharmacologic management of patients with coronary artery disease. While there are a number of imaging modalities that facilitate the assessment of coronary artery pathology, this review paper focuses on intravascular optical imaging modalities that provide information on the microstructural, compositional, biochemical, biomechanical, and molecular features of coronary lesions and stents. The optical imaging modalities discussed include angioscopy, optical coherence tomography, polarization sensitive-optical coherence tomography, laser speckle imaging, near-infrared spectroscopy, time-resolved laser induced fluorescence spectroscopy, Raman spectroscopy, and near-infrared fluorescence molecular imaging. Given the wealth of information that these techniques can provide, optical imaging modalities are poised to play an increasingly significant role in the evaluation of the coronary artery in the future.

Computation of hemodynamics in the left coronary artery with variable angulations

The purpose of this study was to investigate the hemodynamic effect of variations in the angulations of the left coronary artery, based on simulated and realistic coronary artery models. Twelve models consisting of four realistic and eight simulated coronary artery geometries were generated with the inclusion of left main stem, left anterior descending and left circumflex branches. The simulated models included various coronary artery angulations, namely, 15°, 30°, 45°, 60°, 75°, 90°, 105° and 120°. The realistic coronary angulations were based on selected patient's data with angles ranging from narrow angles of 58° and 73° to wide angles of 110° and 120°. Computational fluid dynamics analysis was performed to simulate realistic physiological conditions that reflect the in vivo cardiac hemodynamics. The wall shear stress, wall shear stress gradient, velocity flow patterns and wall pressure were measured in simulated and realistic models during the cardiac cycle. Our results showed that a disturbed flow pattern was observed in models with wider angulations, and wall pressure was found to reduce when the flow changed from the left main stem to the bifurcated regions, based on simulated and realistic models. A low wall shear stress gradient was demonstrated at left bifurcations with wide angles. There is a direct correlation between coronary angulations and subsequent hemodynamic changes, based on realistic and simulated models. Further studies based on patients with different severities of coronary artery disease are required to verify our results.

Atherosclerosis in ApoE-deficient mice progresses independently of the NLRP3 inflammasome

The interleukin-1 (IL-1) family of cytokines has been implicated in the pathogenesis of atherosclerosis in previous studies. The NLRP3 inflammasome has recently emerged as a pivotal regulator of IL-1β maturation and secretion by macrophages. Little is currently known about a possible role for the NLRP3 inflammasome in atherosclerosis progression in vivo. We generated ApoE−/− Nlrp3−/−, ApoE−/− Asc−/− and ApoE−/− caspase-1−/− double-deficient mice, fed them a high-fat diet for 11 weeks and subsequently assessed atherosclerosis progression and plaque phenotype. No differences in atherosclerosis progression, infiltration of plaques by macrophages, nor plaque stability and phenotype across the genotypes studied were found. Our results demonstrate that the NLRP3 inflammasome is not critically implicated in atherosclerosis progression in the ApoE mouse model.

Positive correlation between CD137 expression and complex stenosis morphology in patients with acute coronary syndromes

BACKGROUND

CD137, a member of the tumor necrosis factor receptor superfamily, has been reported to be expressed highly in patients with acute coronary syndromes. However, limited information is available on the relationship between CD137 expression and complex stenosis morphology in patients with acute coronary syndromes.

METHODS

Our study included normal controls (n=50), patients with stable angina (SA) (n=80) and patients with acute coronary syndromes (ACS), including unstable angina (UA) (n=70) and acute myocardial infarction (AMI) (n=100). The expression of CD137 in peripheral monocytes was analyzed by flow cytometry. Serum soluble CD137 (sCD137), MMP-9 and MMP-3 levels were measured by enzyme-linked immunosorbent assay kit. All coronary stenoses with ≥50% diameter reduction were assessed by angiographic coronary stenosis morphology.

RESULTS

Patients with ACS(n=170) showed a significant increase of CD137 [23.6±5.7 mean fluorescence intensity (MFI)] expression in peripheral monocytes compared with control (8.4±2.6 MFI) and SA group (7.9±2.1 MFI) (p<0.001). sCD137 also showed higher level in patients with ACS(30.2±8.7 ng/ml) than in control (6.2±1.8 ng/ml) and SA group (7.1±2.1 ng/ml) (p<0.001). Serum MMP-3 and MMP-9 in patients with ACS were 2-times greater than those in control and SA group. A positive correlation was found between MMP-9, MMP-3 and CD137 expression in peripheral monocytes as well as sCD137 levels. An obvious correlation was also observed between soluble or membrane-bound CD137 expression and complex coronary stenoses (r1=0.5548, r2=0.4652, and p<0.001). In the logistic regression model, the independent predictors of ACS were sCD137 (odds ratio 2.671, 95% CI 1.718-4.153, P=0.000), MMP-9 (1.431, 1.043-1.964, P=0.026) and MMP-3 (1.368, 1.038-1.817, P=0.018).

CONCLUSION

Patients with ACS showed significantly positive correlation between CD137 expression and complex coronary stenosis morphology. We speculate that the increased CD137 expression might represent or reflect an instability of atherosclerotic plaques in patients with ACS.

Intravascular laser speckle imaging catheter for the mechanical evaluation of the arterial wall

Laser speckle imaging (LSI) is a novel technique for measuring the mechanical properties of atherosclerotic plaques. In LSI, the decorrelation time constant of speckle intensity fluctuations provides an index of viscoelasticity that is closely related to plaque microstructure and composition. Here, we demonstrate for the first time, the feasibility of conducting LSI in vivo using a prototype 1.5 mm (4.5 Fr) diameter intravascular catheter. Investigation of the catheter performance using human arterial samples ex vivo shows that plaque time constants measured by the LSI catheter correlate well with those measured using a free-space bulk optics system. To demonstrate LSI in vivo, the catheter is interfaced with a portable console for intravascular evaluation in the aorta of a living rabbit. Distinct differences in arterial time constants are identified at normal aortic and stented sites in vivo with intravascular LSI.

Positive correlation between pregnancy-associated plasma protein-A level and OX40 ligand expression in patients with acute coronary syndromes

OBJECTIVE

Increasing evidence show that serum pregnancy-associated plasma protein-A (PAPP-A) and OX40 ligand (OX40L) expression have been implicated in acute coronary syndromes (ACS). We investigated the relationship between PAPP-A level and OX40L in serum and membrane-bound OX40L in patients with ACS.

METHODS

The present study included normal controls (n=30), patients with stable angina (SA) (n=60) and patients with ACS, including unstable angina (UA) (n=50) and acute myocardial infarction (AMI) (n=30). Serum concentrations of PAPP-A and soluble OX40L (sOX40L) were determined with Elisa, whereas the expression of OX40L on monocytes were analyzed with flow cytometry.

RESULTS

The expression of OX40L in peripheral monocytes in patients with UA [25.6±5.5 mean fluorescence intensity (MFI)] and AMI (29.4±6.3MFI) were significantly higher than those in patients with SA (10.6±2.8MFI) and controls (11.1±3.5MFI). Both sOX40L and PAPP-A in patients with UA (15.7±4.9ng/mL, 25.4±6.8μg/mL, respectively) and AMI (17.1±5.3ng/mL, 26.3±5.6μg/mL, respectively) were significantly higher than those in patients with SA (3.4±1.4ng/mL, 9.6±2.1μg/mL, respectively) and controls (3.9±1.3ng/mL, 8.5±2.8μg/mL, respectively) (P<0.001). Interestingly, a positive correlation was found between sOX40L, membrane-bound OX40L and serum PAPP-A levels (r(1)=0.54, r(2)=0.51; P<0.0001). Both serum and membrane-bound OX40L and PAPP-A levels significantly correlated with complex coronary stenosis (r(1)=0.56, r(2)=0.55, r(3)=0.40; P<0.001).

CONCLUSION

PAPP-A level was significantly related to soluble and membrane-bound OX40L in patients with ACS. Enhanced level of serum PAPP-A and sOX40L might represent a prognostic marker for coronary disease activity.

Elevated level of ADAMTS4 in plasma and peripheral monocytes from patients with acute coronary syndrome

OBJECTIVES

A recent study shows that ADAMTS4 is expressed in macrophage-rich areas of human atherosclerotic carotid plaques and coronary unstable plaques, suggesting a pathogenic role of ADAMTS4 in the development of acute coronary syndrome (ACS). We investigated (a) whether the expression level of ADAMTS4 in plasma and peripheral blood mononuclear cells was affected; and (b) whether there was a relationship with hs-CRP level and the stability of coronary atherosclerotic plaque in patients with ACS.

METHODS

Our study included 30 normal controls and 120 patients including 40 with stable angina (SA), 50 with unstable angina (UA), and 30 with acute myocardial infarction (AMI). The expression of ADAMTS4 in monocytes was analyzed by RT-PCR and plasma ADAMTS4 level was determined by ELISA. All coronary stenosis with >30% diameter reduction was assessed by angiographic coronary stenosis morphology.

RESULTS

Patients with ACS showed a significant increase of ADAMTS4 (2.7 ± 0.4) expression in monocytes compared with controls (1.1 ± 0.2) and the SA group (1.3 ± 0.2) (P < 0.001). Plasma ADAMTS4 also showed a higher level in ACS patients (100.2 ± 31.6 ng/ml) than in control (47.5 ± 9.0 ng/ml, P < 0.001) and the SA group (54.3 ± 13.2 ng/ml, P < 0.001). Moreover, we found a positive correlation between hs-CRP and ADAMTS4 expression in monocytes as well as in plasma. There was also a positive correlation of ADAMTS4 expression in monocytes and plasma with complex coronary stenosis (r (1) = 0.61, r (2) = 0.57, P < 0.001).

CONCLUSIONS

Patients with ACS showed increased ADAMTS4 expression, which may aggravate the development of atherosclerosis and instability of atherosclerotic plaques. Therefore, the ADAMTS4 expression may be a valuable marker for predicting the severity of ACS.

The relationship between CD40 gene polymorphism and unstable coronary atherosclerotic plaques

BACKGROUND

Recently, CD40 polymorphism was found to be associated with acute coronary syndromes. However, few study was involved in the relationship between CD40 polymorphism and the risk of the vulnerable plaque to rupture so far.

MATERIALS AND METHODS

A total of 699 patients who have received coronary angiography were divided into 3 groups according to the morphological division of the plaques: complex lesions (343 cases), smooth lesions (131 cases), and control group (225 cases).The gene polymorphism was measured by the polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) and identified by sequencing.

RESULTS

The CC genotype and C allele frequency of the CD40 gene in the complex lesions group is significantly higher than in the smooth lesions group and the control group (P < .001), while the TT genotype frequency in the complex lesions group is significantly lower than that of the smooth lesions group and the control group (P < .001). The C allele increased disruption risk of the plaques in the complex lesions group as compared with the smooth lesions group (odds ratio [OR]: 1.697, 95% confidence interval [CI]: 1.273-2.261). No significant differences in genotypes or allele frequencies were found between the smooth lesions group and the control group.

CONCLUSION

Our results suggested that CD40 (-1C/T) polymorphism was associated with unstable coronary atherosclerotic plaques. The C allele frequency increased the risk of disruption of the coronary atherosclerotic plaques.

High-affinity alphavbeta3 integrin targeted optical probe as a new imaging biomarker for early atherosclerosis: initial studies in Watanabe rabbits

PURPOSE

A newly developed synthetic alpha v beta 3 integrin targeted optical probe (ITOP) has been demonstrated to target cancer cells, in vivo. Compared to the commercially available cyclic peptide c[RGDfv], this optical probe has at least 20 times better binding affinity for the alpha v beta 3 receptor. The present in vitro study was designed to investigate the possibility of detecting early atherosclerotic plaque by using this ITOP.

PROCEDURES

Experiments were performed on five Watanabe heritable hyperlipidemic rabbits and two New Zealand White rabbits for control. Our ITOP was used for detecting the presence of alpha v beta 3 receptors in vitro.

RESULTS

Segments of plaque accumulation from two distinct regions of ascending and descending aortas were labeled in Watanabe rabbits. The signal was found principally in the adventitia and proximal intima of the aortic vessel, corresponding directly to the expression of integrin alpha v beta 3 as determined by antibody assay. Moreover, there was a close association between the level of labeling with the alpha v beta 3 targeted probe and the thickness of the adventitia.

CONCLUSIONS

This high-affinity ITOP identifies the site and extent of alpha v beta 3 expression and correlates with adventitial thickness. Recent evidence associates alpha v beta 3 expression with the inflammatory process in early vulnerable plaque, making this compound a promising potential biomarker for early atherosclerotic disease.

MR plaque imaging of the carotid artery

Atherosclerotic carotid plaque represents a major cause of cerebral ischemia. The detection of vulnerable plaque is important for preventing future cardiovascular events. The key factors in advanced plaque that are most likely to lead to patient complications are the condition of the fibrous cap, the size of the necrotic core and hemorrhage, and the extent of inflammatory activity within the plaque. Magnetic resonance (MR) imaging has excellent soft tissue contrast and can allow for a more accurate and objective estimation of carotid wall morphology and plaque composition. Recent advances in MR imaging techniques have permitted serial monitoring of atherosclerotic disease evolution and the identification of intraplaque risk factors for accelerated progression. The purpose of this review article is to review the current state of techniques of carotid wall MR imaging and the characterization of plaque components and surface morphology with MR imaging, and to describe the clinical practice of carotid wall MR imaging for the determination of treatment plan.

Epigenetics in atherosclerosis and inflammation

Atherosclerosis is a multifactorial disease with a severe burden on western society. Recent insights into the pathogenesis of atherosclerosis underscore the importance of chronic inflammation in both the initiation and progression of vascular remodelling. Expression of immunoregulatory molecules by vascular wall components within the atherosclerotic lesions is accordingly thought to contribute to the ongoing inflammatory process. Besides gene regulatory proteins (transcription factors), epigenetic mechanisms also play an essential and fundamental role in the transcriptional control of gene expression. These epigenetic mechanisms change the accessibility of chromatin by DNA methylation and histone modifications. Epigenetic modulators are thus critically involved in the regulation of vascular, immune and tissue-specific gene expression within the atherosclerotic lesion. Importantly, epigenetic processes are reversible and may provide an excellent therapeutic target. The concept of epigenetic regulation is gradually being recognized as an important factor in the pathogenesis of atherosclerosis. Recent research provides an essential link between inflammation and reprogramming of the epigenome. In this review we therefore discuss the basis of epigenetic regulation – and the contribution thereof in the regulation of inflammatory processes in general and during atherosclerosis in particular. Moreover we highlight potential therapeutic interventions based on epigenetic mechanisms.

Laser speckle imaging of atherosclerotic plaques through optical fiber bundles

Laser speckle imaging (LSI), a new technique that measures an index of plaque viscoelasticity, has been investigated recently to characterize atherosclerotic plaques. These prior studies demonstrated the diagnostic potential of LSI for detecting high-risk plaques and were conducted ex vivo. To conduct intracoronary LSI in vivo, the laser speckle pattern must be transmitted from the coronary wall to the image detector in the presence of cardiac motion. Small-diameter, flexible optical fiber bundles, similar to those used in coronary angioscopy, may be incorporated into an intravascular catheter for this purpose. A key challenge is that laser speckle is influenced by inter-fiber leakage of light, which may be exacerbated during bundle motion. In this study, we tested the capability of optical fiber bundles to transmit laser speckle patterns obtained from atherosclerotic plaques and evaluated the influence of motion on the diagnostic accuracy of fiber bundle-based LSI. Time-varying helium-neon laser speckle images of aortic plaques were obtained while cyclically moving the flexible length of the bundle to mimic coronary motion. Our results show that leached fiber bundles may reliably transmit laser speckle images in the presence of cardiac motion, providing a viable option to conduct intracoronary LSI.

The clinical implications of increased OX40 ligand expression in patients with acute coronary syndrome

BACKGROUND

Increasing evidence show that OX40 ligand (OX40L), also known as tumor necrosis factor superfamily member 4 (TNFSF4), plays an important role in the pathogenesis of atherosclerosis. We investigated whether expression levels of soluble OX40L in serum and of membrane OX40L on platelets were related to serum concentrations of matrix metalloproteinases (MMPs) and stability of coronary atherosclerotic plaque in patients with acute coronary syndrome (ACS).

METHODS

We included healthy controls (n=30), patients with stable angina (SA) (n=40) and patients with ACS, including unstable angina (UA) (n=70) and acute myocardial infarction (AMI) (n=40). The expression of OX40L on platelets (pOX40L) was analyzed with flow cytometry whereas serum concentrations of soluble OX40L (sOX40L), MMP-9 and MMP-3 were determined with ELISA. All coronary stenoses with >or=30% diameter reduction were assessed by angiographic coronary stenosis morphology.

RESULTS

The expression of OX40L on platelets were significantly higher in patients with ACS (61.5+/-11.5) compared with healthy controls (28.9+/-7.4) or with the group of patients with SA (31.2+/-8.1) (mean fluorescence intensity+/-SD) (p<0.001). Similarly, we observed higher sOX40L concentrations in patients with ACS (34.6+/-9.3) compared with controls (10.2+/-4.7) or patients with SA (11.4+/-5.8) (ng/ml+/-SD) (p<0.001). Serum MMP-3 and MMP-9 levels in patients were two times greater than those in the control group. A positive correlation was observed between OX40L expression on platelets and MMP-9 and MMP-3 serum concentrations. OX40L expression on platelets were furthermore correlated with soluble OX40L in serum and with complex coronary stenoses (r1=0.61, r2=0.57, p<0.001).

CONCLUSION

Patients with ACS show increased OX40L system (pOX40L and sOX40L) expression which may create a proinflammatory milieu for aggravating the development of atherosclerosis, and may be a valuable marker for predicting the severity of ACS.

Evaluation of collagen in atherosclerotic plaques: the use of two coherent laser-based imaging methods

Acute coronary events such as myocardial infarction are frequently caused by the rupture of unstable atherosclerotic plaque. Collagen plays a key role in determining plaque stability. Methods to measure plaque collagen content are invaluable in detecting unstable atherosclerotic plaques. Recently, novel coherent laser-based imaging techniques, such as polarization-sensitive optical coherence tomography (PSOCT) and laser speckle imaging (LSI) have been investigated, and they provide a wealth of information related to collagen content and plaque stability. Additionally, given their potential for intravascular use, these technologies will be invaluable for improving our understanding of the natural history of plaque development and rupture and, hence, enable the detection of unstable plaques. In this article we review recent developments in these techniques and potential challenges in translating these methods into intra-arterial use in patients.

Intracoronary ultrasound examinations reveal significantly more advanced coronary atherosclerosis in people with type 1 diabetes than in age- and sex-matched non-diabetic controls

AIMS/HYPOTHESIS

The extent of coronary atherosclerosis is significantly more advanced in symptomatic type 1 diabetes patients than in symptomatic non-diabetic patients. Whether this difference exists between asymptomatic individuals with diabetes and controls is not documented. In vivo imaging techniques allow quantification of the difference at a preclinical stage.

METHODS

The degree of coronary atherosclerosis in early onset type 1 diabetes patients without symptoms of cardiovascular disease was compared with that of age- and sex-matched controls. Intracoronary ultrasound (IVUS) examinations were performed to determine the degree of atherosclerosis. The mean age of the patients was 43 years (35-58), they had a mean duration of disease of 30 (23-39) years and the diagnosis of type 1 diabetes was made at a mean age of 12.5 years. The controls were people with transplanted hearts; donors were sex- and age-matched and had a mean age of 43 (35-58) years.

RESULTS

The degree of subclinical coronary atherosclerosis was significantly more severe in type 1 diabetes patients than in controls. This was the case for all parameters measured. The mean plaque area was >or= 40% in 71% (54/76) of diabetic arteries as opposed to 33% (25/76) of arteries from controls (p<0.0001). The mean plaque thickness was 0.59+/-0.38 mm vs. 0.44+/-0.30 mm in controls (p<0.0001). The mean lumen area was 8.6+/-3.8 mm2 in type 1 diabetes and 12.1+/-4.3 mm2 in controls (p<0.0001).

CONCLUSIONS/INTERPRETATION

Asymptomatic individuals with type 1 diabetes have significantly more advanced subclinical coronary atherosclerosis than controls. Coronary atherosclerosis in type 1 diabetes develops at an early age.

Non-ST Segment Elevation Acute Coronary Syndromes: A Comprehensive Review

As the non-ST segment elevation acute coronary syndromes (NSTEACS) include unstable angina pectoris (UAP) and the non-ST segment elevation myocardial infarction (NSTEMI), acute diagnosis and risk stratification can often prove challenging. This review will cover guidelines and strategies for risk assessment, contemporary approaches to acute patient management as well as recommendations for timing of specialist referral.

Impact of follow-up time and re-measurement of the electrocardiogram and conventional cardiovascular risk factors on their predictive value for myocardial infarction

OBJECTIVE

To explore if the predictive power of mid-life electrocardiogram (ECG) abnormalities and conventional cardiovascular risk factors for future myocardial infarction, change over a 30-year follow-up period and if repeated examination improves their predictive power.

DESIGN AND SETTING

Longitudinal population-based study.

PARTICIPANTS

A total of 2322 men aged 50 years, with a total follow-up period of 30 years and 1221 subjects were re-examined at age of 70 years.

MAIN OUTCOME MEASURE

Risk for fatal and nonfatal myocardial infarction (n = 470) analysed at age 50 and 70 years, and separately for 1-10, 11-20 and 21-30 years after first examination. Investigations included a 12-lead ECG, blood pressure, body mass index, smoking habits, and glucose and lipid variables.

RESULTS

Whilst high blood pressure and dyslipidaemia variables, such as apolipoprotein B/apolipoprotein A1 ratio, measured at age 50 showed an almost unchanged predictive power during the three decades of follow up, ECG abnormalities, insulin and BMI were only significant predictors during the two first decades of follow up. Despite increased prevalences of ECG abnormalities and obesity with age, they predicted for future myocardial infarction in midlife only whilst fasting insulin and smoking regained their predictive power when re-measured at age 70.

CONCLUSION

Whilst hypertension and dyslipidaemia were consistent as risk factors, length of follow-up period and age at baseline investigations affected the predictive power of ECG abnormalities, fasting insulin, BMI and smoking. In the elderly, ECG abnormalities did not contribute to the prediction of myocardial infarction but smoking and fasting insulin may be important in the pathophysiology leading to MI especially in this age group.

Characterization of atherosclerotic plaques by laser speckle imaging

BACKGROUND

A method capable of determining atherosclerotic plaque composition and measuring plaque viscoelasticity can provide valuable insight into intrinsic features associated with plaque rupture and can enable the identification of high-risk lesions. In this article, we describe a new optical technique, laser speckle imaging (LSI), that measures an index of plaque viscoelasticity. We evaluate the potential of LSI for characterizing atherosclerotic plaque.

METHODS AND RESULTS

Time-varying helium-neon laser speckle images were acquired from 118 aortic plaque specimens from 14 human cadavers under static and deforming conditions (0 to 200 microm/s). Temporal fluctuations in the speckle patterns were quantified by exponential fitting of the normalized cross-correlation of sequential frames in each image series of speckle patterns to obtain the exponential decay time constant, tau. The decorrelation time constants of thin-cap fibroatheromas (TCFA) (tau=47.5+/-19.2 ms) were significantly lower than those of other atherosclerotic lesions (P<0.001), and the sensitivity and specificity of the LSI technique for identifying TCFAs were >90%. Speckle decorrelation time constants demonstrated strong correlation with histological measurements of plaque collagen (R=0.73, P<0.0001), fibrous cap thickness (R=0.87, P<0.0001), and necrotic core area (R=-0.81, P<0.0001). Under deforming conditions (10 to 200 microm/s), tau correlated well with cap thickness in necrotic core fibroatheromas (P>0.05).

CONCLUSIONS

The measurement of speckle decorrelation time constant from laser speckle images provides an index of plaque viscoelasticity and facilitates the characterization of plaque type. Our results demonstrate that LSI is a highly sensitive technique for characterizing plaque and identifying thin-cap fibroatheromas.

Carotid Atherosclerotic Plaque Characteristics Are Associated With Microembolization During Carotid Endarterectomy and Procedural Outcome

Background and Purpose— During carotid endarterectomy (CEA), microemboli may occur, resulting in perioperative adverse cerebral events. The objective of the present study was to investigate the relation between atherosclerotic plaque characteristics and the occurrence of microemboli or adverse events during CEA.

Methods— Patients (n=200, 205 procedures) eligible for CEA were monitored by perioperative transcranial Doppler. The following phases were discriminated during CEA: dissection, shunting, release of the clamp, and wound closure. Each carotid plaque was stained for collagen, macrophages, smooth muscle cells, hematoxylin, and elastin. Semiquantitative analyses were performed on all stainings. Plaques were categorized into 3 groups based on overall appearance (fibrous, fibroatheromatous, or atheromatous).

Results— Fibrous plaques were associated with the occurrence of more microemboli during clamp release and wound closure compared with atheromatous plaques ( P =0.04 and P =0.02, respectively). Transient ischemic attacks and minor stroke occurred in 5 of 205 (2.4%) and 6 of 205 (2.9%) patients, respectively. Adverse cerebral outcome was significantly related to the number of microembolic events during dissection ( P =0.003) but not during shunting, clamp release, or wound closure. More cerebrovascular adverse events occurred in patients with atheromatous plaques (7/69) compared with patients with fibrous or fibroatheromatous plaques (4/138) ( P =0.04).

Conclusions— Intraoperatively, a higher number of microemboli were associated with the presence of a fibrous but not an atheromatous plaque. However, atheromatous plaques were more prevalent in patients with subsequent immediate adverse events. In addition, specifically the number of microemboli detected during the dissection phase were related to immediate adverse events.

Predicting No-reflow Based on Angiographic Features of Lesions in Patients with Acute Myocardial Infarction

OBJECTIVES

We tried to elucidate angiographical predictors of no-reflow and to determine a preferable recanalization therapy based on the morphology of lesions.

METHODS

Seventy-six patients were randomly assigned into groups to receive primary angioplasty (n = 41) or intracoronary thrombolysis (n = 35). Based on angiography, occlusive infarct-related lesions were divided into thrombus-rich and hard plaque lesions. The outcome of the two therapies used for each lesion was compared.

RESULTS

The incidence of no-reflow was higher in the thrombus-rich than hard plaque lesions (38 percent vs. 0 percent, p = 0.006); the left ventricular ejection fraction in the chronic phase was lower (46 +/- 6 percent vs. 55 +/- 5 percent, p < 0.001) for primary angioplasty than thrombolysis. No-reflow was not observed in the hard plaque lesions. However, the incidence of additional reperfusion therapy (88 percent vs. 8 percent, p < 0.001) was higher in the patients who underwent thrombolysis rather than primary angioplasty.

CONCLUSIONS

We suggest that thrombus-rich lesions in primary angioplasty may predict no-reflow in acute myocardial infarction, and thrombolysis prior to angioplasty may be preferable for these lesions. We also suggest that primary angioplasty may be more effective than thrombolysis for hard plaque lesions.

Drug therapies to prevent coronary plaque rupture and erosion: present and future

Patients at high risk for coronary heart disease usually have a number of atherosclerotic plaques in their coronary arteries. Some plaques grow inward and, once they have caused a critical degree of luminal stenosis, lead to chronic anginal symptoms. Other plaques grow outward and remain silent unless they disrupt and trigger an acute coronary event. Either type of plaque may become vulnerable to rupture or erosion once they have reached an advanced stage. Typically, a highly stenotic fibrotic plaque is prone to erosion, whereas an advanced lipid-rich thin-cap fibroatheroma is prone to rupture. Because of the multitude and complex nature of the coronary lesions and our inability to detect silent rupture-prone plaques, the best practical approach to prevent acute coronary events is to treat the vulnerable patient, i.e., to eliminate the risk factors of coronary disease. Despite such preventive measures, a sizable number of patients still experience acute coronary events due to plaque erosion or rupture. Thus, there is room for new avenues to pharmacologically stabilize vulnerable plaques. The development of new noninvasive tools to detect the progression and regression of individual non-stenotic rupture-prone plaques will allow testing of such novel pharmacotherapies. Because no specific plaque-targeted therapies are available at present, we give an overview of the current pharmacotherapy to treat the vulnerable patient and also discuss potential novel therapies to prevent acute coronary events.

Atherothrombotic risk factor clustering in healthy male relatives of male patients with intermittent claudication

OBJECTIVE

Family history is an independent risk factor for premature acute myocardial infarction; in contrast, familial risk for peripheral arterial disease (PAD) has yet to be determined. Elevated levels of hemostatic proteins are consistently predictive for cardiovascular risk in "healthy" subjects, and may cluster with underlying insulin resistance. Atherothrombotic risk factor clustering occurs in first-degree relatives of subjects with coronary artery disease and type 2 diabetes. These may contribute to the enhanced cardiovascular risk in these subjects, and we hypothesised that familial clustering may occur in PAD. The objective of this study was to measure atherothrombotic risk factors in healthy male first-degree relatives of men with intermittent claudication, with emphasis on thrombotic risk.

METHODS

One hundred sixty-five healthy male first-degree relatives were compared with control subjects matched for age, sex, and race (n = 165), free from a personal or family history of premature cardiovascular disease. Primary outcome measures were fibrinogen, von Willebrand factor, factor VII clotting activity (FVII:C), and factor XIII levels. Atherosclerotic risk factors were measured, and subjects were genotyped for common functional polymorphisms (factor VII r353q and fibrinogen B beta-455).

RESULTS

Relatives had higher mean levels of fibrinogen (3.04 vs 2.89 g/L; P = .021), FVII:C (117% vs 104%; P = .000), factor XIII B subunit (1.11 vs 1.01 IU/mL; P = .000), and complex (A 2 B 2 ; 1.18 vs 1.11 IU/mL; P = .021). At multivariate analysis the association between relative status and fibrinogen, FVII:C, and factor XIII B subunit levels were independent of other variables.

CONCLUSIONS

The healthy male relatives of men with PAD have elevated levels of fibrinogen, factor VII, and factor XIII. Our results support the existence of thrombotic risk factor clustering in this population at "high risk."

Simvastatin promotes atherosclerotic plaque stability in apoE-deficient mice independently of lipid lowering

OBJECTIVE

This study sought to determine whether simvastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, has stabilizing effects on vulnerable atherosclerotic plaques that are independent of their lipid-lowering capabilities.

METHODS AND RESULTS

Simvastatin (50 mg/kg per day) was administered to 30-week-old apolipoprotein E-deficient mice exhibiting advanced unstable atherosclerotic lesions within the innominate/brachiocephalic artery. Simvastatin was administered in the chow to separate groups of mice for 6, 12, 18, or 24 weeks. Simvastatin significantly increased serum cholesterol after 12, 18, and 24 weeks of treatment. The average cross-sectional area of atherosclerotic lesion increased in the innominate artery after 12 and 24 weeks of treatment, concomitant with the increase in serum cholesterol. However, histological analysis of sections of the innominate artery stained with Movat and von Kossa stains demonstrated a 49% reduction in the frequency of intraplaque hemorrhage and a 56% reduction in the frequency of calcification, both markers of advanced and unstable atherosclerotic plaques.

CONCLUSIONS

These data suggest that despite an increase in serum cholesterol and lesion size, simvastatin has stabilizing effects on advanced atherosclerotic lesions.

Prevention of a first myocardial infarction

Coronary heart disease is the leading cause of morbidity and mortality in men and women in the Western world. We now have significant evidence that prevention of the first coronary event using lifestyle and pharmacologic therapies is paramount. Events are caused by inflamed arteries leading to rupture of atherosclerotic plaques that induce potentially occlusive thrombi. Analysis of event reduction trials has revealed that LDL-C lowering is only one part of the therapy needed to stabilize plaque. HMG-Co-A-reductase inhibitors, fibrates, and statins all have differing mechanisms of action that provide not only lipid but also inflammatory, rheologic, and coagulation benefits. Concentration and sizes of lipoprotein subfractions have emerged as important new tools with small dense LDL particles having more atherogenicity, which has led to an increasing use of aggressive combination therapy for prevention of first myocardial infarction. Proper use of lipid-lowering therapies requires knowledge of drug metabolism drug-drug interactions.

Effect of amlodipine on the progression of atherosclerosis and the occurrence of clinical events. PREVENT Investigators

BACKGROUND

The results of angiographic studies have suggested that calcium channel-blocking agents may prevent new coronary lesion formation, the progression of minimal lesions, or both.

METHODS AND RESULTS

The Prospective Randomized Evaluation of the Vascular Effects of Norvasc Trial (PREVENT) was a multicenter, randomized, placebo-controlled, double-masked clinical trial designed to test whether amlodipine would slow the progression of early coronary atherosclerosis in 825 patients with angiographically documented coronary artery disease. The primary outcome was the average 36-month angiographic change in mean minimal diameters of segments with a baseline diameter stenosis of 30%. A secondary hypothesis was whether amlodipine would reduce the rate of atherosclerosis in the carotid arteries as assessed with B-mode ultrasonography, which measured intimal-medial thicknesses (IMT). The rates of clinical events were also monitored. The placebo and amlodipine groups had nearly identical average 36-month reductions in the minimal diameter: 0.084 versus 0.095 mm, respectively (P:=0.38). In contrast, amlodipine had a significant effect in slowing the 36-month progression of carotid artery atherosclerosis: the placebo group experienced a 0.033-mm increase in IMT, whereas there was a 0. 0126-mm decrease in the amlodipine group (P:=0.007). There was no treatment difference in the rates of all-cause mortality or major cardiovascular events, although amlodipine use was associated with fewer cases of unstable angina and coronary revascularization.

CONCLUSIONS

Amlodipine has no demonstrable effect on angiographic progression of coronary atherosclerosis or the risk of major cardiovascular events but is associated with fewer hospitalizations for unstable angina and revascularization.

The apolipoprotein epsilon4 allele determines prognosis and the effect on prognosis of simvastatin in survivors of myocardial infarction : a substudy of the Scandinavian simvastatin survival study

BACKGROUND

Carriers of the epsilon4 allele of the apolipoprotein E gene are at a higher risk of coronary heart disease than individuals with other genotypes. We examined whether the risk of death or a major coronary event in survivors of myocardial infarction depended on apolipoprotein E genotype and whether the benefits of treatment with simvastatin differed between genotypes.

METHODS AND RESULTS

Cox proportional hazards models were used to analyze 5.5 years of follow-up data from 966 Danish and Finnish myocardial infarction survivors enrolled in the Scandinavian Simvastatin Survival Study. A total of 16% of the 166 epsilon4 carriers in the placebo group died compared with 9% of the 312 patients without the allele, which corresponds to a mortality risk ratio of 1.8 (95% confidence interval, 1.1 to 3.1). The risk ratio was unaffected by considerations of sex, age, concurrent angina, diabetes, smoking, and serum lipids in multivariate analyses. Simvastatin treatment reduced the mortality risk to 0.33 (95% confidence interval, 0.16 to 0.69) in epsilon4 carriers and to 0.66 (95% confidence interval, 0. 35 to 1.24) in other patients (P=0.23 for treatment by genotype interaction). Apolipoprotein E genotype did not predict the risk of a major coronary event. Baseline serum levels of lipoprotein(a) also predicted mortality risk and could be combined with epsilon4-carrier status to define 3 groups of patients with different prognoses and benefits from treatment.

CONCLUSIONS

Myocardial infarction survivors with the epsilon4 allele have a nearly 2-fold increased risk of dying compared with other patients, and the excess mortality can be abolished by treatment with simvastatin.

Crystallization of free cholesterol in model macrophage foam cells

-The present study examined free cholesterol (FC) crystallization in macrophage foam cells. Model foam cells (J774 or mouse peritoneal macrophages [MPMs]) were incubated with acetylated low density lipoprotein and FC/phospholipid dispersions for 48 hours, resulting in the deposition of large stores of cytoplasmic cholesteryl esters (CEs). The model foam cells were then incubated for up to 5 days with an acyl-coenzyme A:cholesterol acyltransferase (ACAT) inhibitor (CP-113,818) in the absence of an extracellular FC acceptor to allow intracellular accumulation of FC. FC crystals of various shapes and sizes formed in the MPMs but not in the J774 macrophages. Examination of the MPM monolayers by microscopy indicated that the crystals were externalized rapidly after formation and thereafter continued to increase in size. Incubating J774 macrophages with 8-(4-chlorophenylthio)adenosine 3':5'-cyclic monophosphate (CPT-cAMP) in addition to CP-113,818 caused FC crystal formation as a consequence of CPT-cAMP stimulation of CE hydrolysis and inhibition of cell growth. In addition, 2 separate cholesterol phases (liquid-crystalline and cholesterol monohydrate) in the plane of the membrane bilayer were detected after 31 hours of ACAT inhibition by the use of small-angle x-ray diffraction of J774 macrophage foam cells treated with CPT-cAMP. Other compounds reported to inhibit ACAT, namely progesterone (20 microgram/mL) and N-acetyl-D-sphingosine (c(2)-ceramide, 10 microgram/mL), induced cellular toxicity in J774 macrophage foam cells and FC crystallization when coincubated with CPT-cAMP. Addition of the extracellular FC acceptors apolipoproteins (apo) E and A-I (50 microgram/mL) reduced FC crystal formation. In MPMs, lower cell density and frequent changes of medium were conducive to crystal formation. This may be due to "dilution" of apoE secreted by the MPMs and is consistent with our observation that the addition of exogenous apoE or apoA-I inhibits FC crystal formation in J774 macrophage foam cells cotreated with CP-113,818 plus CPT-cAMP. These data demonstrate that FC crystals can form from the hydrolysis of cytoplasmic stores of CEs in model foam cells. FC crystal formation can be modulated by the addition of extracellular FC acceptors or by affecting the cellular rate of CE hydrolysis. This process may contribute to the formation of FC crystals in atherosclerotic plaques.

Extent and composition of coronary lesions in relation to fat distribution in women younger than 50 years of age

To ascertain the relationship between the extent and composition of coronary arterial lesions and the regional distribution of fat in healthy women younger than 50 years of age, a series of 30 forensic autopsy cases were investigated. Body height and weight, waist and hip circumferences, and the thickness of the subscapular and abdominal subcutaneous fat were measured; the body mass index (BMI) and waist-to-hip ratio (WHR) were calculated, and omental and mesenteric fat deposits were weighed. The extent of coronary lesions was measured by planimetry, and the thickness of the intima-media was measured by computerized image analysis. Intimal macrophage foam cells and smooth muscle cells were detected by immunohistochemistry, and macrophages were quantified. The intima media thickness in the left anterior descending artery, circumflex artery, and right coronary artery varied significantly across the tertiles of WHR when age and BMI were adjusted, being highest when WHR exceeded 0.87. The thickest lesions also contained the largest numbers of macrophage foam cells. The intima-media thicknesses were highest with increased amounts of intraperitoneal fat. These results indicate that the severity of clinically silent coronary lesions in younger female individuals is associated with increased WHR and increased amounts of intraperitoneal fat. These results emphasize the importance of WHR as a coronary risk indicator in younger women.