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.

The FREEDOM Study: A Pilot Study Examining the Feasibility and Safety of Early Walking following Femoral Manual Compression after Endovascular Interventions Using 5F Sheath-Compatible Devices.

BACKGROUND: Increasing prevalence of peripheral arterial disease (PAD) burning and pressure to reduce costs and promote patient empowerment make outpatient endovascular procedures an attractive alternative to conventional hospitalization. For outpatient peripheral endovascular procedures, femoral manual compression could replace the use of arterial closure devices for small-bore punctures. Presently, safety and feasibility evidence for femoral manual compression is still lacking. FREEDOM is a pilot study designed to demonstrate the feasibility and safety of early walking after femoral manual puncture point compression following a therapeutic endovascular procedure for PAD. METHODS: From May to August 2015, all patients requiring endovascular treatment for PAD were prospectively screened. Those patients that received therapeutic endovascular procedures involving retrograde femoral punctures with a 5F sheath were included. Manual compression and pressure dressing of the femoral puncture points was applied. The primary end point was defined as the walking ability 5 hr after index procedure (H5), which was assessed by a walk test. RESULTS: In total, 129 consecutive patients were screened, and 30 patients met the study criteria. The mean age was 66 ± 11 years. The mean duration of the procedure and of the manual compression was 63 ± 24 min and 12.8 ± 4 min, respectively. At 5 hr following the procedure, 97% of the patients were able to walk 100 m. Two patients failed to walk due to cardiac arrhythmia and to a false aneurysm at the femoral puncture site. No further complications were observed at 1 month, and quality of life assessed by EQ-5D test was significantly increased compare to baseline (72.3 vs. 60.4; P = 0.001). CONCLUSIONS: This pilot study demonstrated the benefits of manual compression to close arterial punctures over procedures using 5F shealth-compatible endovascular devices. A sufficiently powered randomized controlled trial is needed to further characterize the potential benefits of manual compression following use of low-profile devices.

Impact of Vascular Calcifications on Long Femoropopliteal Stenting Outcomes.

BACKGROUND: Vascular calcifications (VCs) may be a prognostic factor for outcome after endovascular treatment of peripheral arterial disease (PAD). Semiquantitative analysis with X-ray imaging is the main limiting factor for assessing VCs. The aim of the present study was to find a correlation between the amount of VC with computed tomography (CT) scan quantification and midterm results of endovascular treatment of Trans-Atlantic Inter-Society Consensus C/D femoropopliteal (FP) lesions. METHODS: Patients belonging to 2 previously published registries (STELLA and STELLA PTX) and who underwent a preoperative CT scan were retrospectively included in the study. VC quantification was performed with a dedicated workstation (EndoSize, Therenva) on the basis of Hounsfield units (HU). The VC percentage was calculated as the ratio between VC volume and the volume of the region of interest. For the analysis, patients were divided into 3 groups according to VC percentage, from lowest to highest: group 1 (G1) included the first quartile of VCs, group 2 (G2) included the second and third quartiles, and group 3 (G3) included the fourth quartile. Risk of in-stent thrombosis was analysed using a multivariate model. RESULTS: Thirty-nine patients were included (10 in G1, 19 in G2, and 10 in G3), and mean follow-up duration was 24 ± 14.6 months. Patients in G1 and G3 had, respectively, a VC rate of <1% (no VC) and >20% (severe VC). In G2, VC was considered to be intermediate. There was no statistical difference in the cardiovascular risk factors and preoperative medication. A significant difference was found for the healthy FP diameter between G1 (4.6 ± 0.8 mm) and G3 (6.8 ± 0.8 mm, P < 0.0001) and between G2 (5.2 ± 1 mm) and G3 (P < 0.0001). The rate of drug-eluting stents was similar in all groups. There was no difference between groups concerning the rate of in-stent restenosis, target lesion revascularization, and target extremity revascularization. There was a higher rate of in-stent thrombosis for G1 versus G2 (P = 0.037), and no difference was noted between G1 versus G3 (P = 0.86) or G2 versus G3 (P = 0.12). G3 was associated with early stent thrombosis (<1 month), while G1 was associated with late stent thrombosis (6-24 months). On multivariate analysis, only one predictive factor for stent thrombosis was found: patients with intermediate VC seemed to be protected against in-stent thrombosis (odds ratio = 0.27, 95% confidence interval: 0.1-0.77; P = 0.014). CONCLUSIONS: The study showed that VC quantification with CT imaging is feasible and useful for comparing outcomes following PAD endovascular revascularization. Below a certain threshold, the presence of VC might be necessary for plaque stability and may protect against in-stent thrombosis.

Mechanisms of erosion of atherosclerotic plaques.

PURPOSE OF REVIEW: The present review explores the mechanisms of superficial intimal erosion, a common cause of thrombotic complications of atherosclerosis. RECENT FINDINGS: Human coronary artery atheroma that give rise to thrombosis because of erosion differ diametrically from those associated with fibrous cap rupture. Eroded lesions characteristically contain few inflammatory cells, abundant extracellular matrix, and neutrophil extracellular traps (NETs). Innate immune mechanisms such as engagement of Toll-like receptor 2 (TLR2) on cultured endothelial cells can impair their viability, attachment, and ability to recover a wound. Hyaluronan fragments may serve as endogenous TLR2 ligands. Mouse experiments demonstrate that flow disturbance in arteries with neointimas tailored to resemble features of human eroded plaques disturbs endothelial cell barrier function, impairs endothelial cell viability, recruits neutrophils, and provokes endothelial cells desquamation, NET formation, and thrombosis in a TLR2-dependent manner. SUMMARY: Mechanisms of erosion have received much less attention than those that provoke plaque rupture. Intensive statin treatment changes the characteristic of plaques that render them less susceptible to rupture. Thus, erosion may contribute importantly to the current residual burden of risk. Understanding the mechanisms of erosion may inform the development and deployment of novel therapies to combat the remaining atherothrombotic risk in the statin era.

Genesis and growth of extracellular-vesicle-derived microcalcification in atherosclerotic plaques.

Clinical evidence links arterial calcification and cardiovascular risk. Finite-element modelling of the stress distribution within atherosclerotic plaques has suggested that subcellular microcalcifications in the fibrous cap may promote material failure of the plaque, but that large calcifications can stabilize it. Yet the physicochemical mechanisms underlying such mineral formation and growth in atheromata remain unknown. Here, by using three-dimensional collagen hydrogels that mimic structural features of the atherosclerotic fibrous cap, and high-resolution microscopic and spectroscopic analyses of both the hydrogels and of calcified human plaques, we demonstrate that calcific mineral formation and maturation results from a series of events involving the aggregation of calcifying extracellular vesicles, and the formation of microcalcifications and ultimately large calcification areas. We also show that calcification morphology and the plaque's collagen content-two determinants of atherosclerotic plaque stability-are interlinked.

Bare Metal Versus Paclitaxel-Eluting Stents for Long Femoropopliteal Lesions: Prospective Cohorts Comparison Using a Propensity Score-Matched Analysis.

BACKGROUND: The study aims to compare outcomes of primary stenting of long femoropopliteal (FP) lesions with bare metal stent (BMS) versus paclitaxel eluting stent (PES). METHODS: In a single centre study, we established 2 consecutive and prospective cohorts with TASC C/D FP de novo lesions. The inclusion and exclusion criteria were similar. Bare metal stent (LifeStent®, Bard Peripheral) and PES (Zilver® PTX®, Cook Peripheral Vascular) were implanted. Prospective clinical and morphological follow-ups were carried out at 1, 3, 6, 12, and 18 months. Propensity score (inverse probability of treatment weighted method) stratification was used to minimize bias. RESULTS: In total, 110 limbs were treated (STELLA: n = 62; STELLA PTX: n = 48). We noted some difference between both cohorts regarding type 2 diabetes (P = 0.05), vitamin K antagonist use (P = 0.05), and angiotensin II receptor blocker use (P = 0.002). More stents were implanted in the STELLA PTX cohort (P < 0.0013). At 12 months, in univariate analysis, freedom from target lesion revascularization (TLR) was higher in the STELLA cohort (P = 0.005). No differences were found between both cohorts in terms of primary sustained clinical improvement (P = 0.25), primary patency (P = 0.07), and survival (P = 0.79). With the propensity score, no difference was observed in terms of primary sustained clinical improvement (P = 0.79), freedom from TLR (P = 0.59), and primary patency (P = 0.69). With Cox logistic regression, the number of implanted stents influenced the primary sustained clinical improvement, the freedom from TLR, and the primary patency. CONCLUSIONS: Paclitaxel-eluting stents do not seem to provide benefits in terms of clinical and morphological outcomes for TASC C/D lesions compared to BMS.

Moderate hypoxia potentiates interleukin-1ß production in activated human macrophages.

RATIONALE: Inflammation drives atherogenesis. Animal and human studies have implicated interleukin-1ß (IL-1ß) in this disease. Moderate hypoxia, a condition that prevails in the atherosclerotic plaque, may conspire with inflammation and contribute to the evolution and complications of atherosclerosis through mechanisms that remain incompletely understood. OBJECTIVE: This study investigated the links between hypoxia and inflammation by testing the hypothesis that moderate hypoxia modulates IL-1ß production in activated human macrophages. METHODS AND RESULTS: Our results demonstrated that hypoxia enhances pro-IL-1ß protein, but not mRNA, expression in lipopolysaccharide-stimulated human macrophages. We show that hypoxia limits the selective targeting of pro-IL-1ß to autophagic degradation, thus prolonging its half-life and promoting its intracellular accumulation. Furthermore, hypoxia increased the expression of NLRP3, a limiting factor in NLRP3 inflammasome function, and augmented caspase-1 activation in lipopolysaccharide-primed macrophages. Consequently, hypoxic human macrophages secreted higher amounts of mature IL-1ß than did normoxic macrophages after treatment with crystalline cholesterol, an endogenous danger signal that contributes to atherogenesis. In human atherosclerotic plaques, IL-1ß localizes predominantly to macrophage-rich regions that express activated caspase-1 and the hypoxia markers hypoxia-inducible factor 1α and hexokinase-2, as assessed by immunohistochemical staining of carotid endarterectomy specimens. CONCLUSIONS: These results indicate that hypoxia potentiates IL-1ß expression in cultured human macrophages and in the context of atheromata, therefore unveiling a novel proinflammatory mechanism that may participate in atherogenesis.

TLR2 and neutrophils potentiate endothelial stress, apoptosis and detachment: implications for superficial erosion.

AIMS: Superficial erosion of atheromata causes many acute coronary syndromes, but arises from unknown mechanisms. This study tested the hypothesis that Toll-like receptor-2 (TLR2) activation contributes to endothelial apoptosis and denudation and thus contributes to the pathogenesis of superficial erosion. METHODS AND RESULTS: Toll-like receptor-2 and neutrophils localized at sites of superficially eroded human plaques. In vitro, TLR2 ligands (including hyaluronan, a matrix macromolecule abundant in eroded lesions) induced endothelial stress, characterized by reactive oxygen species production, endoplasmic reticulum (ER) stress, and apoptosis. Co-incubation of neutrophils with endothelial cells (ECs) potentiated these effects and induced EC apoptosis and detachment. We then categorized human atherosclerotic plaques (n = 56) based on morphologic features associated with superficial erosion, 'stable' fibrotic, or 'vulnerable' lesions. Morphometric analyses of the human atheromata localized neutrophils and neutrophil extracellular traps (NETs) near clusters of apoptotic ECs in smooth muscle cell (SMC)-rich plaques. The number of luminal apoptotic ECs correlated with neutrophil accumulation, amount of NETs, and TLR2 staining in SMC-rich plaques, but not in 'vulnerable' atheromata. CONCLUSION: These in vitro observations and analyses of human plaques indicate that TLR2 stimulation followed by neutrophil participation may render smooth muscle cell-rich plaques susceptible to superficial erosion and thrombotic complications by inducing ER stress, apoptosis, and favouring detachment of EC.

Matrix metalloproteinase-13 predominates over matrix metalloproteinase-8 as the functional interstitial collagenase in mouse atheromata.

OBJECTIVE: Substantial evidence implicates interstitial collagenases of the matrix metalloproteinase (MMP) family in plaque rupture and fatal thrombosis. Understanding the compensatory mechanisms that may influence the expression of these enzymes and their functions, therefore, has important clinical implications. This study assessed in mice the relative effect of the 2 principal mouse collagenases on collagen content and other plaque characteristics. APPROACH AND RESULTS: Apolipoprotein E-deficient (apoE(-/-)) mice, MMP-13(-/-) apoE(-/-), MMP-8(-/-) apoE(-/-) double knockout mice, and MMP-13(-/-) MMP-8(-/-) apoE(-/-) triple knockout mice consumed a high-cholesterol diet for 10 and 24 weeks. Both double knockout and triple knockout mice showed comparable atherosclerotic lesion formation compared with apoE(-/-) controls. Analysis of aortic root sections indicated that lesions of MMP-8/MMP-13-deficient and MMP-13-deficient mice accumulate more fibrillar collagen than apoE(-/-) controls and MMP-8(-/-) apoE(-/-) double knockout. We further tested the relative effect of MMPs on plaque collagenolysis using in situ zymography. MMP-13 deletion alone abrogated collagenolytic activity in lesions, indicating a predominant role for MMP-13 in this process. MMP-13 and MMP-13/MMP-8 deficiency did not alter macrophage content but associated with reduced accumulation of smooth muscle cells. CONCLUSIONS: These results show that among MMP interstitial collagenases in mice, MMP-13 prevails over MMP-8 in collagen degradation in atheromata. These findings provide a rationale for the identification and selective targeting a predominant collagenase for modulating key aspects of plaque structure considered critical in clinical complications, although they do not translate directly to human lesions, which also contain MMP-1.

Molecular imaging of atherosclerosis for improving diagnostic and therapeutic development.

Despite recent progress, cardiovascular and allied metabolic disorders remain a worldwide health challenge. We must identify new targets for therapy, develop new agents for clinical use, and deploy them in a clinically effective and cost-effective manner. Molecular imaging of atherosclerotic lesions has become a major experimental tool in the last decade, notably by providing a direct gateway to the processes involved in atherogenesis and its complications. This review summarizes the current status of molecular imaging approaches that target the key processes implicated in plaque formation, development, and disruption and highlights how the refinement and application of such tools might aid the development and evaluation of novel therapeutics.