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Background and aims In one-third of patients with acute coronary syndrome (ACS), thrombosis occurs despite an intact fibrous cap (IFC) (IFC–ACS, 'plaque erosion'). Recent studies emphasize neutrophils as the immediate inflammatory response in this pathology, but their exact molecular activation patterns are still poorly understood and may represent future therapeutic targets. Methods and results Thirty-two patients with IFC–ACS and matched patients with ACS with ruptured fibrous cap (RFC) (RFC–ACS) from the OPTICO–ACS study were included, and blood samples were collected from the local site of the culprit lesion and the systemic circulation. Neutrophil surface marker expression was quantified by flow cytometry. Neutrophil cytotoxicity towards endothelial cells was examined in an ex vivo co-culture assay. Secretion of active matrix metalloproteinase 9 (MMP9) by neutrophils was evaluated using zymography in supernatants and in plasma samples. Optical coherence tomography (OCT)–embedded thrombi were used for immunofluorescence analysis. Toll-like receptor 2 (TLR2) expression was higher on neutrophils from IFC–ACS than RFC–ACS patients. TLR2 stimulation increased the release of active MMP9 from local IFC–ACS–derived neutrophils, which also aggravated endothelial cell death independently of TLR2. Thrombi of IFC–ACS patients exhibited more hyaluronidase 2 with concomitant increase in local plasma levels of the TLR2 ligand: hyaluronic acid. Conclusion The current study provides first in-human evidence for distinct TLR2-mediated neutrophil activation in IFC–ACS, presumably triggered by elevated soluble hyaluronic acid. Together with disturbed flow conditions, neutrophil-released MMP9 might be promoting endothelial cell loss–triggered thrombosis and therefore providing a potential future target for a phenotype-specific secondary therapeutic approach in IFC–ACS. [ABSTRACT FROM AUTHOR]

Objective: Occult atrial fibrillation (AF) is a significant risk factor for occult stroke but is difficult to detect. Myocardial strain, based on speckle tracking echocardiography (STE), can detect subclinical changes in left atrial (LA) function. This study aimed to investigate the diagnostic value of LA strain in identifying asymptomatic AF patients with normal electrocardiograms and healthy volunteers. Methods: A total of 354 subjects were retrospectively enrolled. Patients were divided into two groups based on whether they had AF during echocardiography. Patients with sinus rhythm during echocardiography were further divided into healthy control group and occult AF group. Patients with AF during echocardiography were further divided into paroxysmal AF group and persistent AF group. LA mechanical function measured by STE was compared between patients with asymptomatic AF and volunteers. Conventional echocardiographic indicators were measured. The diagnostic value of LA strain for identifying asymptomatic AF was assessed by univariate and multivariate regression analysis and receiver operating characteristic (ROC) curves. Results: Occult AF patients had higher NT‐proBNP levels, larger RA area, larger LAVmax and decreased LAEF than control group. However, occult AF patients had lower NT‐proBNP levels, RA area and LAVmax and higher LAEF than paroxysmal and persistent AF. The measured LA reservoir strain (LASr), LA conduit strain (LAScd), LA contraction strain (LASct) of occult AF group was significantly lower than that of control group. However, occult AF patients had preserved LAScd and LASct than paroxysmal and persistent AF. RA area, LAEF and LASr were remarkable correlation with occult AF after adjustment for NT‐proBNP, LAVmax, and LAScd. The area under curve of ROC for LASr was the greatest among RA area, LAEF and LASr, with a cut‐off value of 34.1% (sensitivity: 75.4%, specificity: 87.6%). Conclusion: LASr can identify occult AF in the asymptomatic population. Patients with LASr values ≤34.1% have a higher incidence of occult cardiac dysfunction. These findings help identify patients with occult AF and further risk stratification for the AF population. [ABSTRACT FROM AUTHOR]

Improving the flame retardancy and lightweight of fluorosilicone rubber (FSR) foam is important for its application in aerospace, rail transportation, petrochemical equipment, etc. In this work, ammonium polyphosphate (APP) and expandable graphite (EG) were used as synergistic flame retardants, and the lightweight FSR composite foam with flame retardancy was prepared by supercritical N2 foaming. When there were 12.5 phr APP and 7.5 phr EG, the composite foam with density of 0.254 g/cm3 showed superiority in foaming performance and flame retardancy, and the limit oxygen index was 36.4%, the UL‐94 grade reached V‐0, the ignition time was 12 s and the fire performance index was 0.071 s·m2/kW. In addition, the aging, oil and solvent resistance of FSR foam was not affected. This work provided data support for the production and application of the flame retardant FSR foam. [ABSTRACT FROM AUTHOR]

Background: The purpose of the study was to determine the association between vena contracta area (VCA) and secondary leaflet tethering among mitral valve prolapse (MVP) patients, and thus to further identify and characterize an MVP with pathological leaflet tethering (MVPt+) phenotype. Methods: We prospectively evaluated 94 consecutive MVP patients with significant mitral regurgitation (MR) and 21 healthy controls. MVPt+ group was defined as tenting volume index (TVi) >.7 mL/m2. The three‐dimensional (3D) geometry of mitral valve apparatus and VCA was measured with dedicated quantification software. Results: Of the 94 patients with MVP and significant MR, 31 patients showed a TVi >.7 mL/m2 and entered the MVP with leaflet tethering (MVPt+) group. In stepwise multivariate analysis, only prolapse volume index and TVi were independently associated with 3D VCA. 3D VCA, annular area index, and plasma levels of NT‐proBNP were independently correlated with the severity of leaflet tethering. ROC curve revealed that a 3D VCA ≥.55 cm2 is the optimal cutoff point to predict MVPt+ phenotype. Conclusions: Secondary leaflet tethering is a significant mechanism behind severe degenerative MR, resulting in an MVPt+ phenotype featuring more advanced morphological and hemodynamical characteristics. [ABSTRACT FROM AUTHOR]