Histologic atherosclerotic plaque characteristics are associated with restenosis rates after endarterectomy of the common and superficial femoral arteries

Identification of necroptosis-related gene TRAF5 as potential target of diagnosing atherosclerosis and assessing its stability

BACKGROUND

Atherosclerosis (AS) is a leading cause of morbidity and mortality in older patients and features progressive formation of plaques in vascular tissues. With the progression of atherosclerosis, plaque rupture may occur and cause stroke, myocardial infarction, etc. Different forms of cell death promote the formation of a necrotic core of the plaque, leading to rupture. Necroptosis is a type of programmed cell death that contributes to the development of cardiovascular disease. However, the role of necroptosis in AS has not yet been investigated.

METHODS

The Gene Expression Omnibus (GEO) database was used to obtain gene expression profiles. Differentially expressed genes (DEGs) and necroptosis gene sets were used to identify necroptosis-related differentially expressed genes (NRDEGs). The NRDEGs were used to construct a diagnostic model and were further screened using least absolute shrinkage selection operator (LASSO) regression and random forest (RF) analysis. The discriminatory capacity of the NRDEGs was evaluated using receiver operating characteristic (ROC) curves. Immune infiltration levels were estimated based on CIBERSORTx analysis. The GSE21545 dataset, containing survival information, was used to determine prognosis-associated genes. Univariate and multivariate Cox regression analyses combined with survival analysis determined gene prognostic values. RNA and protein levels were detected by RT-qPCR and western blotting in arteriosclerosis obliterans(ASO) and normal vascular tissues. Vascular smooth muscle cells (VSMCs) were treated with oxidized low-density lipoprotein (ox-LDL) to develop cell models of advanced AS. The effects of protein knockdown on necroptosis were assessed by western blotting and flow cytometry. EdU and Cell Counting Kit-8 assays were used to examine cell proliferation.

RESULTS

TNF Receptor Associated Factor 5 (TRAF5) was identified as a diagnostic marker for AS based on the AUC value in both the GSE20129 and GSE43292 datasets. According to differential expression analysis, LASSO regression analysis, RF analysis, univariate analysis, multivariate analysis, and gene-level survival analysis, TRAF5 was markedly associated with necroptosis in AS. Silencing TRAF5 promotes necroptosis and attenuates the proliferation of ox-LDL-induced cell models of advanced AS.

CONCLUSIONS

This study identified a diagnostic marker of necroptosis-related atherosclerosis, TRAF5, which can also be used to diagnose and assess atherosclerotic plaque stability. This novel finding has important implications in the diagnosis and assessment of plaque stability in atherosclerosis.

Correlation between Coronary Artery Disease with Other Arterial Systems: Similar, Albeit Separate, Underlying Pathophysiologic Mechanisms

Atherosclerosis is a multifactorial systemic disease that affects the entire arterial tree, although some areas are more prone to lipid deposits than others. Moreover, the histopathological composition of the plaques differs, and the clinical manifestations are also different, depending on the location and structure of the atherosclerotic plaque. Some arterial systems are correlated with each other more than in that they simply share a common atherosclerotic risk. The aim of this perspective review is to discuss this heterogeneity of atherosclerotic impairment in different arterial districts and to investigate the current evidence that resulted from studies of the topographical interrelations of atherosclerosis.

The Role of the Coagulation System in Peripheral Arterial Disease: Interactions with the Arterial Wall and Its Vascular Microenvironment and Implications for Rational Therapies

Peripheral artery disease (PAD) is a clinical manifestation of atherosclerotic disease with a large-scale impact on the economy and global health. Despite the role played by platelets in the process of atherogenesis being well recognized, evidence has been increasing on the contribution of the coagulation system to the atherosclerosis formation and PAD development, with important repercussions for the therapeutic approach. Histopathological analysis and some clinical studies conducted on atherosclerotic plaques testify to the existence of different types of plaques. Likely, the role of coagulation in each specific type of plaque can be an important determinant in the histopathological composition of atherosclerosis and in its future stability. In this review, we analyze the molecular contribution of inflammation and the coagulation system on PAD pathogenesis, focusing on molecular similarities and differences between atherogenesis in PAD and coronary artery disease (CAD) and discussing the possible implications for current therapeutic strategies and future perspectives accounting for molecular inflammatory and coagulation targets. Understanding the role of cross-talking between coagulation and inflammation in atherosclerosis genesis and progression could help in choosing the right patients for future dual pathway inhibition strategies, where an antiplatelet agent is combined with an anticoagulant, whose role, despite pathophysiological premises and trials' results, is still under debate.

The Long Non-coding RNA AC148477.2 Is a Novel Therapeutic Target Associated With Vascular Smooth Muscle Cells Proliferation of Femoral Atherosclerosis

Arteriosclerosis obliterans (ASO) is a limb manifestation of large vessel atherosclerosis. Phenotype switching of vascular smooth muscle cells (VSMCs) occurs in the course of the pathological process. The underlying mechanism of SMCs proliferation remains unclear. Several studies have demonstrated that the dysregulation of long non-coding RNA (lncRNAs) plays a pivotal part in the progression of ASO by exacerbating the proliferation of VSMCs. Based on the endogenous competitive RNA (ceRNA) hypothesis, the mechanism of lncRNAs involved in the pathology of VSMCs was exposed, while the entire map of the regulatory network remains to be elucidated. In the current study, genes and the lncRNAs modules that are relevant to the clinical trait were confirmed through weighted gene co-expression network analysis (WGCNA). In this study, we comprehensively constructed a specific lncRNAs-mediated ceRNA and RBP network. The three lncRNAs, HMGA1P4, C5orf66, and AC148477.2, influenced the proliferation of VSMCs and were found to be associated with the immune landscape, thus they were ultimately screened out. Further verification revealed that AC147488.2 was significantly down-regulated in both ASO arteries and all stages of proliferative VSMCs, which implied that AC147488.2 might have a significant impact on ASO. This finding would improve our understanding of the epigenetic regulation of ASO and unravel novel diagnostic and therapeutic targets.

Role of Extracellular Vesicles as Potential Diagnostic and/or Therapeutic Biomarkers in Chronic Cardiovascular Diseases

Cardiovascular diseases (CVDs) are the first cause of death worldwide. In recent years, there has been great interest in the analysis of extracellular vesicles (EVs), including exosomes and microparticles, as potential mediators of biological communication between circulating cells/plasma and cells of the vasculature. Besides their activity as biological effectors, EVs have been also investigated as circulating/systemic biomarkers in different acute and chronic CVDs. In this review, the role of EVs as potential diagnostic and prognostic biomarkers in chronic cardiovascular diseases, including atherosclerosis (mainly, peripheral arterial disease, PAD), aortic stenosis (AS) and aortic aneurysms (AAs), will be described. Mechanistically, we will analyze the implication of EVs in pathological processes associated to cardiovascular remodeling, with special emphasis in their role in vascular and valvular calcification. Specifically, we will focus on the participation of EVs in calcium accumulation in the pathological vascular wall and aortic valves, involving the phenotypic change of vascular smooth muscle cells (SMCs) or valvular interstitial cells (IC) to osteoblast-like cells. The knowledge of the implication of EVs in the pathogenic mechanisms of cardiovascular remodeling is still to be completely deciphered but there are promising results supporting their potential translational application to the diagnosis and therapy of different CVDs.

Characteristics of atherosclerosis in femoropopliteal artery and its clinical relevance

Atherosclerosis is a systemic disease with different faces. Despite identical or similar pathogenetic mechanisms, atherosclerotic lesions and their clinical manifestations vary in different parts of the vascular system. Peripheral arterial disease (PAD) represents one of the most frequent clinical manifestations of atherosclerosis with predominant location in the superficial femoral artery (SFA). Morphological characteristics of atherosclerotic plaques in peripheral arteries differ from lesions in the coronary and carotid arteries. Plaques in SFA have more fibrotic components, less lipids and inflammatory cells, which makes them more stable and less prone to rupture. Factors that determine the different structure of plaques in SFA compared to coronary arteries include hemodynamic forces, vasa vasorum and calcification. Low shear stress in SFA in the adductor canal is one of the factors which determines frequent atherosclerotic lesions in this region. Lower lipid content and fewer inflammatory cells explain higher stability of SFA plaques. The specific structure of SFA plaques may require preventive and therapeutic measures, which to some extent differ from prevention of coronary atherosclerosis and may include inhibition of fibrotic proliferation in SFA plaques and calcification. Revascularization of PAD differs from procedures used in coronary arteries and requires specific technical expertise and devices.

The age- and sex-specific composition of atherosclerotic plaques in vascular surgery patients

BACKGROUND AND AIMS

The sex- and age-related differences in the composition of iliofemoral atherosclerotic plaques are largely unknown. Therefore, the aim of the current study is to gain insight into plaque composition across strata of age and sex in a large cohort of vascular surgery patients.

METHODS

Peripheral atherosclerotic plaques of patients who underwent iliofemoral endarterectomy (n = 790) were harvested between 2002 and 2014. The plaques were semi-quantitatively analyzed for the presence of lipid cores, calcifications, plaque hemorrhages (PH), collagen, macrophage and smooth muscle cell (SMC) content, and quantitatively for microvessel density. Patients were stratified by age tertiles and sex.

RESULTS

Ageing was independently associated with rupture-prone iliofemoral plaque characteristics, such as higher prevalence of plaque calcifications (OR 1.52 (95%CI:1.03-2.24) p = 0.035) and PH (OR 1.46 (95%CI:1.01-2.09) p = 0.042), and lower prevalence of collagen (OR 0.52 (95%CI:0.31-0.86) p = 0.012) and SMCs (OR 0.59 (95%CI:0.39-0.90) p = 0.015). Sex-stratified data showed that men had a higher prevalence of lipid cores (OR 1.62 (95%CI:1.06-2.45) p = 0.025) and PH (OR 1.62 (95%CI:1.16-2.54) p = 0.004) compared to women. These sex-differences attenuated with increasing age, with women showing an age-related increase in calcifications (p = 0.002), PH (p = 0.015) and decrease in macrophages (p = 0.005). In contrast, men only showed a decrease in collagen (p = 0.043).

CONCLUSIONS

Atherosclerotic iliofemoral plaques derived from men display more rupture-prone characteristics compared to women. Yet, this difference is attenuated with an increase in age, with older women having more rupture-prone characteristics compared to younger women.

Efficacy of the Decalcification of Heavily Calcified Femoral Bifurcation Lesions Using a Cavitron Ultrasonic Surgical Aspirator

BACKGROUND

In the current diabetes era, severe calcified femoral bifurcation lesions extending to the external elastic lamina are sometimes experienced and are technically challenging during conventional endarterectomy. We previously reported an alternative method, a decalcification technique with a Cavitron Ultrasonic Surgical Aspirator (CUSA), for calcified lesions. This study aimed to clarify the efficacy of CUSA decalcification technique.

METHODS

A total of 26 limbs treated with CUSA decalcification from 2014 to 2017 were enrolled and evaluated hemodynamically with ankle-brachial index (ABI) and morphologically with computed tomography angiography (CTA). ABI was measured every 6 months, and CTA was performed early after surgery and then annually thereafter. Curved planar reformation images and cross-sectional multiplanar reconstruction images obtained by CTA were used to measure the cross-sectional area of the common femoral artery (CFA). Then, the time courses of the ABI and CFA areas were analyzed.

RESULTS

The operative indication was claudication in 80.8%, rest pain in 7.7%, and tissue loss in 11.5% of the cases. A concomitant profundaplasty was performed in 34.6% of the cases. One case of an intraoperative arterial wall perforation was experienced as a procedure-related complication. Hemodynamic success rate was 96.2% (preoperative ABI: 0.37 ± 0.28, postoperative ABI: 0.75 ± 0.15, P < 0.0001) and technical success rate was 100.0% (preoperative CFA area: 4.1 ± 5.9 mm², postoperative CFA area: 46.1 ± 17.0 mm², P < 0.0001), with clinical improvement achieved in 95.8% of cases. Primary and secondary patency rates of the CFA were 100.0% at 2 years postoperatively, and the reintervention-free rate for the ipsilateral limb was 88.5% at 2 years postoperatively. Over a median follow-up period of 28.0 months (range, 12.3-67.0 months), the restenosis rate of CFA was 7.6%, when restenosis was defined as a >50% decrease in cross-sectional area.

CONCLUSIONS

CUSA decalcification is a safe and effective alternative method to treat heavily calcified femoral lesions with a good patency rate and a low restenosis rate.

Coronary and peripheral artery plaques: do differences in plaque characteristics translate to differences in lipid management?

Optimal medical management of patients with peripheral arterial disease (PAD) includes statin therapy, which has been shown to decrease the risk of major cardiovascular events. However, the relationship between low-density lipoprotein (LDL) lowering, PAD progression and limb outcomes remains controversial. Although prevention of coronary and cerebrovascular events is a priority, limb outcomes are still important determinants of quality of life and healthcare spending. This review will highlight differences between coronary artery disease (CAD) and PAD, and in particular, the more prevalent role of lipids and LDL cholesterol in CAD versus calcification in PAD. This difference may contribute to the differential impact of LDL cholesterol levels on coronary events and outcomes versus limb outcomes. Beyond LDL lowering, immune modulators have emerged as another agent to treat atherosclerosis in CAD, however similar data in PAD are lacking. Small studies have suggested that other lipids besides LDL cholesterol, such as triglycerides or small dense LDL, may have a greater impact on limb outcomes in patients with PAD. Although statin therapy is central in the management of patients with PAD, current understanding of the distinctions between PAD and CAD suggest that there may be other non-LDL targets for risk reduction that require further study.

Impact of Femoral Ossification on Local and Systemic Cardiovascular Patients' Condition

BACKGROUND

Vascular calcifications are associated with a high cardiovascular morbi-mortality in the coronary territory. In parallel, femoral arteries are more calcified and develop osteoid metaplasia (OM). This study was conducted to assess the predictive value of OM and local inflammation on the occurrence of mid- and long-term adverse cardiovascular events.

METHOD

Between 2008 and 2015, 86 atheromatous samples were harvested during femoral endarterectomy on 81 patients and processed for histomorphological analyses of calcifications and inflammation (monocytes and B cells). Histological findings were compared with the long-term follow-up of patients, including major adverse cardiac event (MACE), major adverse limb event (MALE), and mortality. Frequencies were presented as percentage, and continuous data, as mean and standard deviation. A P-value < 0.05 was considered statistically significant.

RESULTS

Median follow-up was 42.4 months (26.9-58.8). Twenty-eight percent of patients underwent a MACE; a MALE occurred in 18 (21%) limbs. Survival rate was 87.2% at 36 months. OM was found in 41 samples (51%), without any significant impact on the occurrence of MACE, MALE, or mortality. Preoperative white blood cell formulae revealed a higher rate of neutrophils associated with MACE (P = 0.04) and MALE (P = 0.0008), correlated with higher B cells counts in plaque samples.

CONCLUSIONS

OM is part of femoral calcifications in almost 50% of the cases but does not seem to be an independent predictive variable for MACE or MALE. However, a higher rate of B cell infiltration of the plaque and preoperative neutrophil blood count may be predictive of adverse events during follow-up.

Improved label-free diagnostics and pathological assessment of atherosclerotic plaques through nonlinear microscopy

Coronary heart disease is the most common type of heart disease caused by atherosclerosis. In fact, an arterial wall lesion centered on the accumulation of cholesterol-rich lipids and the accompanying inflammatory response generates a plaque, whose rupture may result in a thrombus with fatal consequences. Plaque characterization for assessing the severity of atherosclerosis is generally performed through standard histopathological examination based on hematoxylin/eosin staining, which is operator-dependent and requires relatively long procedures. In this framework, nonlinear optical microscopy is a valid, label-free alternative to standard diagnostic methods. We combined second-harmonic generation (SHG), two-photon excited fluorescence (TPEF) and fluorescence lifetime imaging microscopy in a multimodal scheme for obtaining morphological and molecular information on human carotid ex vivo specimens affected by atherosclerosis. In this study, discrimination between different tissues within the atherosclerotic plaque was achieved based on both lifetime, TPEF-to-SHG ratio, and image pattern analysis. The presented methodology aims to be a starting point for future fully automated and fast characterization of atherosclerotic biopsies; moreover, it could be extended to the study of other tissues and pathologies. Combined TPEF/SHG mapping of a carotid specimen affected by atherosclerosis.

Common femoral artery endarterectomy in the age of endovascular therapy

OBJECTIVES

Common femoral artery endarterectomy (CFE) is the standard treatment for common femoral artery occlusive disease. We aim to assess the medium term outcomes of CFE with or without further concomitant procedures.

DESIGN

A retrospective observational study.

METHODS

All patients who underwent either isolated CFE (ICFE), CFE with angioplasty for occlusive arterial disease (CFEA) or concomitant CFE with endovascular aortic aneurysm repair (CFEE) were included. Patient demographics follow up, clinical improvement, types of CFE closure, patency rates, and survival-free amputation were noted.

RESULTS

From 2002 to 2015, 1512 patients were referred with a diagnosis of critical limb ischemia. Of those, 1134 required revascularization. Sixty-one patients underwent 66 CFE. Ten limbs underwent an ICFE, 35 had CFEA, and 21 underwent CFEE. Demographics were comparable in all groups. Twenty-seven were closed primarily, while 39 required patch closure (12 venous, 8 Dacron, 19 biological). Technical success was 100% in ICFEs, 94% in CFEA, and 100% for CFEE ( p = 0.274). Immediate clinical success was 100% in both CFE and CFEE, but was 85.7% in CFEA ( p = 0.035). Immediate hemodynamic success was similar in all three groups ( p = 0.73). Sustained hemodynamic success was 30% in ICFE, 54.3% in CFEA, and 23.8% in CFEE ( p = 0.056). At two years, the primary patency was 90% in ICFE, 74.3% in CFEA, and 100% in CFEE ( p = 0.049). Primary-assisted patency was 90% in ICFE, 82.9% in CFEA, and 100% in CFEE ( p = 0.17). Secondary patency was 90% in ICFE, 94.3% in CFEA, and 100% in CFEE ( p = 0.409). Re-intervention was required in 26.9% of primary closures, versus 12.8% with patch closures ( p = 0.279). Amputation-free survival was 100% in ICFE, 80% in CFEA, and 100% in CFEE ( p = 0.056).

CONCLUSION

CFE is a reliable and dependable procedure, even in the absence of good distal runoff.

Time-dependent trends in cardiovascular adverse events during follow-up after carotid or iliofemoral endarterectomy

BACKGROUND

Recent observations have suggested a decline in vulnerable carotid artery and iliofemoral atherosclerotic plaque characteristics over the past decade. The aim of this study was to determine whether, in the presence of clinically manifest carotid or peripheral artery disease, secondary adverse cardiovascular events decreased over this period.

METHODS

Patients included in the Athero-Express biobank between 2003 and 2012 were analysed. During 3-year follow-up, composite cardiovascular endpoints were documented yearly, including: myocardial infarction, coronary interventions, stroke, peripheral interventions and cardiovascular death. The major cardiovascular endpoint consisted of myocardial infarction, stroke and cardiovascular death.

RESULTS

Some 1684 patients who underwent carotid endarterectomy (CEA) and another 530 who had iliofemoral endarterectomy (IFE) were analysed. In total, 405 (25·2 per cent) and 236 (45·9 per cent) patients had a composite cardiovascular endpoint within 3 years after CEA and IFE respectively. Corrected for possible confounders, the percentage of patients with a secondary cardiovascular event after CEA did not change over time (hazard ratio (HR) 0·91, 95 per cent c.i. 0·65 to 1·28; P = 0·590, for 2011-2012 versus 2003-2004). In patients who had IFE, the incidence of secondary cardiovascular events significantly decreased only in the last 2 years (HR 0·62, 0·41 to 0·94; P = 0·024), owing to a decrease in peripheral (re)interventions in 2011-2012 (HR 0·59, 0·37 to 0·94; P = 0·028). No decrease in major cardiovascular events was observed in either group.

CONCLUSION

In patients who had undergone either CEA or IFE there was no evidence of a decrease in all secondary cardiovascular events. There were no differences in major cardiovascular events.

Towards the development of an in vitro model of atherosclerotic peripheral vessels for evaluating drug-coated endovascular technologies

Here, we review the in vitro models used to evaluate drug-coated endovascular technologies. The models are assessed in the context of representing the drug transport/uptake and mechanical properties of atherosclerotic peripheral vessels. Studies to date have incorporated a vessel-simulating hydrogel compartment to examine drug elution from endovascular devices. However, comparisons between in vitro models and atherosclerotic tissue are difficult because ex vivo data are limited in their applicability to diseased peripheral vessels. Furthermore, appropriate ex vivo mechanical properties are not incorporated into these models. Therefore, there is a need to characterise the drug transport/uptake properties of appropriate atherosclerotic tissue and incorporate existing ex vivo mechanical data into current in vitro models to more accurately represent drug behaviour in atherosclerotic peripheral vessels.

Arterial repair after bare-metal stent implantation in peripheral arteries is delayed compared to that in coronary arteries: A case report of pathological evaluation

Despite widespread use of endovascular therapy with bare-metal stent (BMS) implantation in patients with peripheral artery disease (PAD), arterial healing has not been well examined in this setting. An 84-year-old man with PAD received BMS implantation at the right external iliac artery (EIA, Epic 8.0 mm × 100 mm) and superficial femoral artery (SFA, SMART Control 8.0 mm × 150 mm). However, he died of lobar pneumonia 81 days later. Pathological evaluation was conducted at BMS implantation sites. At the distal part of Epic site in the EIA, neointimal formation was seldom observed. A small amount of fibrin deposition was seen around stent struts without apparent smooth muscle cell proliferation or surface endothelial cell coverage. In contrast, at the middle part of distal SMART site in the SFA, most of the stent struts were completely covered with moderate amount of neointima which was composed of a lot of smooth muscle cells and extracellular matrix on the plaque-free wall. However, on the contralateral calcified plaque site, a lot of fibrin components were still observed over the surface of thin neointima and only rough smooth muscle cells were scatteringly infiltrated. Furthermore, incomplete endothelial cell coverage was seen on the surface. Arterial repair after BMS implantation in peripheral arteries was extremely delayed. <Learning objective: An 84-year-old man with peripheral artery disease received bare-metal stent (BMS) implantation in peripheral arteries. Pathological evaluation 81 days later showed heterogeneous neointimal coverage formation with incomplete coverage, especially at the vessel portions with significant plaque burden. In these portions, endothelial cell coverage was also incomplete. Moreover, some malapposed struts were observed. Arterial repair after BMS implantation in peripheral arteries was extremely delayed.>.

The impact of female sex on long-term survival of patients with severe atherosclerosis undergoing endarterectomy

OBJECTIVES

Long-term age- and sex-specific mortality data in patients undergoing carotid endarterectomy (CEA) and iliac/femoral endarterectomy (FEA) are scarce. We examined long-term mortality in these patient groups, stratified by age and sex.

METHODS

Between 2002 and 2012, 1771 patients (1200 men, 571 women) treated by CEA, and 685 patients (495 men, 190 women) who underwent FEA, were included and linked to the national mortality registry of the Netherlands. Absolute mortality risks during follow-up were analyzed by life-table and Kaplan Meier survival analyses in two age groups and stratified by sex, and compared to a matched sample from the general population. In addition, multivariable Cox regression analyses were performed.

RESULTS

After CEA, with a median follow-up duration of 4.3 years (interquartile range 2.0-7.1), 298 all-cause deaths had occurred in men (25%) and 105 (18%) in women. As in the general population, cumulative survival after CEA was significantly better in women compared to men (P = 0.002) and absolute CEA-associated mortality risk in women was similar to that of the general population. For FEA patients, mortality risk was worse than for CEA patients and the general population in both sexes and surprisingly, female sex did not have a favorable effect on survival. Following FEA, 130 men (26%) and 51 women (27%) died after a median follow-up time of 3.0 years (interquartile range 1.5-5.9). Stratifying by age, and adjusting for cardiovascular risk factors did not change these trends.

CONCLUSIONS

Long-term mortality after CEA is higher in men than in women, and in women mortality risk is similar to the general population. After FEA, the benefit of women as seen after CEA is lost.

Macrophage subtypes in symptomatic carotid artery and femoral artery plaques

OBJECTIVE

To compare differences in macrophage heterogeneity and morphological composition between atherosclerotic plaques obtained from recently symptomatic patients with carotid artery disease and femoral plaques from patients with severe limb ischemia.

DESIGN

Experimental study.

METHODS

Plaques were obtained from 32 patients undergoing carotid endarterectomy and 25 patients undergoing common femoral endarterectomy or lower limb bypass. Macrophages and T cell numbers were detected in plaque sections by immunohistochemistry and anti CD68 and CD3 antibodies. Dual staining for CD68 and M1- and M2-macrophage markers and morphometric analysis of hematoxylin and eosin stained plaque sections was performed.

RESULTS

Carotid plaques had significantly increased percentage areas of confluent lipid and leukocytic infiltrates. In contrast, areas of fibroconnective tissue were significantly greater in femoral plaques and percentage areas of confluent calcification and collagen were elevated. Carotid artery plaques had greater numbers per plaque area of macrophages and T cells consistent with a more inflammatory phenotype. Proportions displaying M1-activation markers were significantly increased in the carotid compared to femoral plaques whereas femoral plaques displayed a greater proportion of M2-macrophages.

CONCLUSION

Plaques from patients with recently symptomatic carotid disease have a predominance of M1-macrophages and higher lipid content than femoral plaques, consistent with a more unstable plaque.