Sex Differences in Plaque Composition and Morphology Among Symptomatic Patients With Mild-to-Moderate Carotid Artery Stenosis

Background and Purpose: Incidence of ischemic stroke differs between men and women, with substantially higher rates in men. The underlying mechanism of this difference remains poorly understood but may be because of differences in carotid atherosclerosis. Using an in-depth imaging-based approach, we investigated differences between carotid plaque composition and morphology in male and female patients with stroke, taking into account differences in total plaque burden. Additionally, we investigated all possible within-artery combinations of plaque characteristics to explore differences between various plaque phenotypes. Methods: We included 156 men and 68 women from the PARISK (Plaque At Risk) study, a prospective cohort study of patients with recent ischemic cerebrovascular symptoms and <70% ipsilateral carotid stenosis. Plaque characteristics (intraplaque hemorrhage [IPH], lipid-rich necrotic core [LRNC], calcifications, thin-or-ruptured fibrous cap, ulcerations, total plaque volume) were assessed with magnetic resonance imaging and multidetector-row computed tomography angiography. We used multivariable logistic and linear regression analyses to assess sex differences in plaque characteristics. Results: We found significant difference in total plaque volume between men and women (β=22.9 mm 3 [95% CI, 15.4–30.5]; mean volume in men 1399±425 mm 3 , in women 1011±242 mm 3 ). Additionally, men were more likely to have IPH (odds ratio [OR]=2.8 [95% CI, 1.3–6.3]; IPH proportion in men 49%, in women 16%) and LRNC (OR=2.4 [95% CI, 1.2–4.7]; LRNC proportion in men 73%, in women 41%) even after adjustment for total plaque volume. We found no sex-specific differences in plaque volume-corrected volumes of IPH, LRNC, and calcifications. In terms of coexistence of plaque characteristics, we found that men had more often a plaque with coexistence of calcifications, LRNC, and IPH (OR=2.7 [95% CI, 1.2–7.0]), with coexistence of thin-or-ruptured fibrous cap/ulcerations, LRNC, and IPH (OR=2.4 [95% CI, 1.1–5.9]), and with coexistence of all plaque characteristics (OR=3.0 [95% CI, 1.2–8.6]). Conclusions: In symptomatic patients with mild-to-moderate carotid stenosis, men are more likely to have a high-risk carotid plaque with IPH and LRNC than women, regardless of total plaque burden. Men also have more often a plaque with multiple vulnerable plaque components, which could comprise an even higher stroke risk. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT01208025.

363 Old but fashioned: IVUS and chromaflo guidance for definition of thrombosis mechanism

Aims Plaque rupture and plaque erosion are the main causes of coronary thrombosis. While the first one involves fibrous cap disruption, the second one is caused by loss of endothelial continuity. In selected cases with evidence of plaque erosion, antithrombotic therapy without stenting has been suggested as a possible option. OCT is considered the gold standard for definition of thrombosis mechanism and has recently been included in algorithms for evaluation and management of patients with ACS. Also, high definition IVUS was compared with OCT in defining plaque erosion showing promising results. However, the cost and the large amount of contrast medium needed for OCT performance make these diagnostic tools of scarce applicability in daily practice. Methods and results We herein describe the case of a young man acceding to the Cath Lab with the diagnosis of NSTEMI. After baseline angiography and IVUS confirmed presence of Thrombus (Figure 1A and B), thromboaspiration was successfully performed (Figure 1D). The definition of thrombosis mechanism, revealing plaque rupture, was then performed with IVUS and ChromaFlo devices (Figure 1C and E). Also, IVUS was used to optimize stent implantation. Conclusions Although requiring further confirmations, we believe that in selected cases IVUS and ChromaFlo could provide a more applicable first-line diagnostic tool to define thrombosis mechanism. 363 Figure 1Baseline angiographic and IVUS evaluation confirming presence of coronary thrombus (A, B). After successful performance of thromboaspiration (D), plaque rupture was revealed by IVUS and ChromaFlo (C).

734 Have I lost my large rupture cavity? The fingerprint of atherosclerotic plaque healing detected by serial optical coherence tomography imaging

A 64-year-old man, prior smoker, with a history of paroxysmal atrial fibrillation was referred to our hospital due to worsening dyspnoea, progressively worsening angina, and a positive stress EKG testing. Coronary angiography (CAG) showed an angiographically intermediate stenosis of the mid left anterior descending (LAD) artery and a focal, complex lesion of the distal right coronary artery (RCA) (Figure 1A and B, red arrow). Treatment of the LAD stenosis was deferred based on a negative fractional flow reserve value (i.e. 0.85). Optical coherence tomography (OCT) imaging (ILUMIEN OPTIS, Abbott Vascular, Santa Clara, CA) was performed to better characterize the RCA lesion, which disclosed a ruptured thin-cap fibroatheroma (TCFA) with a large ‘empty’ cavity (Figure 1C–G, red arrows) and overlying ‘layered’ tissue (Figure 1H, white arrowheads). Based on these OCT findings, suggestive of initial plaque healing, and on a large residual lumen dimension (i.e. minimum lumen area, MLA, at the rupture site: 7.7 mm2), this lesion was not treated with percutaneous coronary intervention. The patient was discharged on aspirin, edoxaban, metoprolol, rosuvastatin, and ezetimibe, and remained clinically stable for more than 1 year. Due to angina recurrence, a new CAG was performed 18 months after the first admission, revealing a progression of the mid LAD stenosis that was treated with a 2.5/28 mm drug-eluting stent, and an improvement of the RCA lesion angiographic appearance (smooth contour) (Figure 1A′–B′). RCA OCT imaging was repeated demonstrating a complete healing of the large rupture cavity with all the hallmarks of the reparative process (Figure 1C′–H′): (1) re-established fibrous cap integrity and smooth vessel lumen profile; (2) thickening of the fibrous cap and reduction of lipid burden (i.e., transformation of TCFA into thick-cap fibroatheroma, ThCFA); (3) replacement of the ‘empty’ cavity with new ‘granulation tissue’; (4) initial calcification of the plaque; (5) heterogeneous signal-rich layers with distinct optical-signal intensity (layered, ‘onion-like’ pattern); and (6) mild lumen narrowing (MLA at the rupture site: 6.9 mm2).

Anti-Galectin-2 antibody treatment reduces atherosclerotic plaque size and alters macrophage polarity

Galectins have numerous cellular functions in immunity and inflammation. Short-term galectin-2 blockade in ischaemia-induced arteriogenesis shifts macrophages to an anti-inflammatory phenotype and improves perfusion. Galectin-2 may also affect other macrophage related cardiovascular diseases. This study aims to elucidate the effects of Galectin-2 inhibition in atherosclerosis. ApoE -/- mice were given a high cholesterol diet (HCD) for 12 weeks. After six weeks of HCD, intermediate atherosclerotic plaques were present. To study the effects of anti-Gal2 nanobody treatment on the progression of existing atherosclerosis, treatment with two llama derived anti-Gal2 nanobodies (clones- 2H8 and 2C10), or vehicle was given for the remaining 6 weeks. Galectin-2 inhibition reduced the progression of existing atherosclerosis. Atherosclerotic plaque area in the aortic root was decreased, especially so in mice treated with 2C10 nanobodies. This clone reduced atherosclerosis severity as reflected by a decrease in fibrous cap atheromas in addition to decreases in plaque size. The number of plaque resident macrophages was unchanged, however, there was a significant increase in the fraction of CD206+ macrophages. 2C10 treatment also increased plaque α-smooth muscle content, and Gal-2 may have a role in modulating the inflammatory status of smooth muscle cells. Remarkably, both treatments reduced serum cholesterol concentrations including reductions in VLDL, LDL, and HDL whilst triglyceride concentrations were unchanged. Prolonged treatment with anti-Gal-2 nanobodies reduced plaque size, slowed plaque progression, and modified the phenotype of plaque macrophages toward an anti-inflammatory profile. These results hold promise for future macrophage modulating therapeutic interventions that promote arteriogenesis and reduce atherosclerosis.

713 Culprit plaque morphology and healing capacity in patients with and without preinfarction angina: an optical coherence tomography imaging study

Aims The relationship between culprit plaque morphology, healed culprit plaques prevalence and clinical presentation of acute myocardial infarction (AMI) remains largely unexplored. We hypothesized that angina preceding the occurrence of AMI (pre-infarction angina, PIA) may reflect a distinct morphologic phenotype of culprit plaques and potentially different healing capacity. Methods and results We conducted a retrospective observational study in patients with AMI who underwent intracoronary optical coherence tomography (OCT) imaging of the culprit lesion before PCI at the Fondazione Policlinico A. Gemelli–Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rome. Based on the clinical history, patients were classified into two groups: (i) PIA group, defined as either intermittent chest pain within 6 h preceding the final episode of chest pain, or unstable angina (or both) in the week preceding AMI or (ii) no-PIA group, defined as a single episode of chest pain without prodromal symptoms in the preceding week. Culprit plaques were classified as plaque rupture (PR) or intact fibrous cap (IFC), and presence of layered appearance (healed plaque, HP) was assessed. Thrombus burden (TB) was estimated, and prevalence of diffuse calcification, neovascularization, and OCT-defined macrophage accumulation were evaluated. A total of 102 patients with AMI were included (50 PIA, 52 no-PIA). Patients with PIA showed a higher prevalence of IFC than PR (58% vs. 42%, P = 0.030). PR in patients with PIA were more frequently associated with macrophage accumulation (71.4% vs. 28.6% P = 0.001), and TB tended to be lower [22.0 (15.8–30.3) vs. 38.5 (12.8–67.5), P = 0.145]. Diffuse calcifications were significantly less frequent in patients with PIA (22.0% vs. 40.4%, P = 0.045), while neovascularization tended to be more frequent (58.0% vs. 42.3%, P = 0.113). HPs prevalence was significantly higher in the PIA than in the no-PIA group (66.0% vs. 25.0%, P &lt; 0.001). Conclusions Patients with PIA have a distinct culprit plaque phenotype, more frequently characterized by IFC and a relatively lower TB, with a significantly higher prevalence of plaque healing.

Is the TCF21 gene protection or risk for coronary artery disease?

Introduction TCF21 is expressed in cells that migrate into the developing plaque facilitating the repair of the vessel wall. However, the rs12190287 risk allele (C) of TCF21 can lead to reduced TCF21 expression being a risk factor for CAD. Purpose Investigate whether the variant rs12190287 G&gt;C of TCF21 gene represents a risk factor for CAD in a Southern European population. Methods Case-control with 3139 individuals, 1723 CAD patients and 1416 controls, adjusted for age and gender. Genotyping of TCF21 rs12190287 G&gt;C was performed by TaqMan Real-Time PCR. CAD association of each genetic model was evaluated. Multivariate logistic regression analysis adjusted for confound variables: smoking status, dyslipidemia, diabetes, physical inactivity, and hypertension, was made. Results TCF21 rs12190287 G&gt;C has shown significant genotypic differences between cases and controls: GG 9.5% vs 11.9%; GC 43.2% vs 46.5% and CC 47.3% vs 41.6%. CAD risk was significant in all models: dominant (OR 1.28; 95% CI: 1.02–1.61; p=0.033); recessive (OR 1.26; 95% CI: 1.09–1.45; p=0.001); additive (OR 1.20; 95% CI: 1.08–1.34; p=0.001). After multivariate analysis, TCF21 variant was independently associated with CAD. Conclusion TCF21 variant rs12190287 G&gt;C may be a risk factor for CAD. It is plausible that TCF21 loci exert its protective effect by promoting infiltration of fibromyocytes in the coronary wall lesion and fibrous layer and loss of TCF21 expression can result in fewer fibromyocytes to fibrous cap increasing vulnerability of the plaque. FUNDunding Acknowledgement Type of funding sources: None. Variables associated with CAD risk

Inflammation during the life cycle of the atherosclerotic plaque

Inflammation orchestrates each stage of the life cycle of atherosclerotic plaques. Indeed, inflammatory mediators likely link many traditional and emerging risk factors with atherogenesis. Atheroma initiation involves endothelial activation with recruitment of leucocytes to the arterial intima, where they interact with lipoproteins or their derivatives that have accumulated in this layer. The prolonged and usually clinically silent progression of atherosclerosis involves periods of smouldering inflammation, punctuated by episodes of acute activation that may arise from inflammatory mediators released from sites of extravascular injury or infection or from subclinical disruptions of the plaque. Smooth muscle cells and infiltrating leucocytes can proliferate but also undergo various forms of cell death that typically lead to formation of a lipid-rich ‘necrotic’ core within the evolving intimal lesion. Extracellular matrix synthesized by smooth muscle cells can form a fibrous cap that overlies the lesion’s core. Thus, during progression of atheroma, cells not only procreate but perish. Inflammatory mediators participate in both processes. The ultimate clinical complication of atherosclerotic plaques involves disruption that provokes thrombosis, either by fracture of the plaque’s fibrous cap or superficial erosion. The consequent clots can cause acute ischaemic syndromes if they embarrass perfusion. Incorporation of the thrombi can promote plaque healing and progressive intimal thickening that can aggravate stenosis and further limit downstream blood flow. Inflammatory mediators regulate many aspects of both plaque disruption and healing process. Thus, inflammatory processes contribute to all phases of the life cycle of atherosclerotic plaques, and represent ripe targets for mitigating the disease.

Macrophages in Atherosclerosis, First or Second Row Players?

Macrophages represent a cell type that has been widely described in the context of atherosclerosis since the earliest studies in the 17th century. Their role has long been considered to be preponderant in the onset and aggravation of atherosclerosis, in particular by participating in the establishment of a chronic inflammatory state by the release of pro-inflammatory cytokines and by uncontrolled engorgement of lipids resulting in the formation of foam cells and later of the necrotic core. However, recent evidence from mouse models using an elegant technique of tracing vascular smooth muscle cells (VSMCs) during plaque development revealed that resident VSMCs display impressive plastic properties in response to an arterial injury, allowing them to switch into different cell types within the plaque, including mesenchymal-like cells, macrophage-like cells and osteochondrogenic-like cells. In this review, we oppose the arguments in favor or against the influence of macrophages versus VSMCs in all stages of atherosclerosis including pre-atherosclerosis, formation of lipid-rich foam cells, development of the necrotic core and the fibrous cap as well as calcification and rupture of the plaque. We also analyze the relevance of animal models for the investigation of the pathophysiological mechanisms of atherosclerosis in humans, and discuss potential therapeutic strategies targeting either VSMCs or macrophage to prevent the development of cardiovascular events. Overall, although major findings have been made from animal models, efforts are still needed to better understand and therefore prevent the development of atherosclerotic plaques in humans.

Thrombus of the Aorta and SARS-CoV-2 Infection: Cause or Trigger?

Objective: Coronavirus disease 19 is a well-established cause of rare arterial thrombosis. Nevertheless, the exact mechanism of arterial thrombosis remains to be elucidated. We herein report the case of a large floating thrombus of the aortic arch, its surgical management and histological analysis.Case: A 65-year-old patient presented to the emergency department with a suspected stroke. He was non-smoker, but presented cardiovascular risk factors, namely hypertension, type 2 diabetes and hyperlipidaemia. A computed tomography of the aorta revealed a large floating thrombus of the aortic arch, at the base of the brachiocephalic trunk, suspected to be the etiology of stroke. Therapeutic anticoagulation was immediately started. The decision was made to perform an open aortic replacement surgery because of the symptomatic thromboembolic event with recent cerebral infarction and the potential harmfulness of the thrombus due to its size. A mobile thrombus was observed at the base of the brachiocephalic trunk by echocardiography. It was attached to a small area of the upper aortic wall and had an irregular surface. Histology revealed a platelet-rich thrombus lying on an aortic atherosclerotic plaque without pronounced inflammation. No plaque ulceration was present but endothelial cell desquamation was observed consistent with plaque erosion.Conclusion: In our case, there was a thrombus lying on an atherosclerotic plaque with intact thick fibrous cap, but associated with a plaque erosion mechanism. The thrombus formation appeared more likely to relate to a very localized endothelial injury.

Abstract P408: Mesenchymal Stem Cell-derived Angptl4 Improves Endothelial Permeability And Resolution Of Inflammation In Atherosclerosis

Objective: Given the fundamental contribution of inflammation to atherosclerosis, we studied the effect of ANGPTL4 in regulating vascular lesions during atherosclerosis. Methods and Results: We analyzed plasma levels of ANGPTL4 and found that acute myocardial infarction (AMI) patients with higher levels of ANGPTL4 had fewer vascular events than did patients with lower ANGPTL4 levels ( p <0.05). Moreover, in AMI patients with heart failure (HF) at admission, the recurrence of HF was lower in patients with a higher level of ANGPTL4. We then investigated the therapeutic application of ANGPTL4 in an atherosclerosis model. Apoe-/- mice fed a high-fat diet were injected with PBS or ANGPTL4 protein (2 μg per mouse, i.p. ) three times per week for 7 weeks. En face staining and mRNA analysis showed that plaque size, necrotic core area, lipid accumulation, and inflammatory molecules were greatly reduced in the ANGPTL4 group. Aortic permeability, measured by leakage of Evans blue dye, was significantly decreased in the ANGPTL4 group. The induction of pro-inflammatory mediators was significantly inhibited in endothelial cells, vascular smooth muscle cells, and macrophages by ANGPTL4 treatment. Endothelial Krüppel-like factor 2 (KLF2) and VE-cadherin were restored to contribute to maintenance of vascular integrity by ANGPTL4 treatment. Elevated levels of circulating leptin, interleukin-6, and interleukin-1β were profoundly reduced. Most importantly, the fibrous cap was significant thicker in the ANGPTL4 group than in the PBS group. Conclusions: ANGPTL4 treatment attenuated atherogenesis, which suggests that targeting vascular stability and inflammation may serve as a novel therapeutic strategy to prevent and treat atherosclerosis. More importantly, ANGPTL4 treatment inhibits necrotic core formation in lesions, leading to the formation of more stable plaques as evidenced by increased fibrous cap thickness.