Plaque Surface Research Articles

Three-Dimensional Visualization of Atherosclerotic Vessels by Tissue Clearing and Light-Sheet Fluorescence Microscopy.

Although arteries and atherosclerotic plaques are three-dimensional structures, the evaluation of plaque size and morphology in preclinical models of atherosclerosis is typically performed in two dimensions by histological analysis. Here, we describe a method to visualize arteries and atherosclerotic plaques in three dimensions. This method combines AdipoClear, a procedure that achieves whole tissue immunolabeling and clearing, and light-sheet fluorescence microscopy, which generates a three-dimensional reconstruction of vessel architecture including atherosclerotic lesions if present. This approach reveals the volume, geometry, acellular component and surface of atherosclerotic plaques as well as the spatial position of the lesion in relation to the affected artery.

Vulnerable Carotid Artery Plaques in Asymptomatic Patients—A Narrative Review

AbstractOver the last two decades, medical management of carotid artery patients has improved significantly. Most patients remain stable on best medical therapy (BMT), making interventions unnecessary in all patients. “Selective” intervention is advocated for only those few patients who are having vulnerable or unstable carotid artery plaques. Literature search was done to explore current concept and role of available investigations to identify vulnerable carotid plaques. Vulnerable plaque is defined as those plaques having active inflammation, high large necrotic lipid content, neovascularity, thin capsule, surface irregularity, or intraplaque hemorrhage. Ultrasound (US) is the simple, noninvasive, cost-effective investigation to differentiate soft (echolucent) from fibrocalcified (echogenic) plaques. It can also comment on other high-risk plaque features such as plaque volume and area. Contrast-enhanced US can visualize neovascularization and plaque surface irregularities better than conventional US. Computed tomography is limited in identifying most high-risk plaque features and is not useful. High-resolution magnetic resonance imaging is the most accurate and externally validated investigation to characterize most high-risk plaque components. Positron emission tomography has emerged as the most promising dynamic investigation to identify and quantify inflammatory plaques and will be clinically very useful in decision making.

Platelets and other cells interactions in the atherosclerosis development

Atherosclerosis of the blood vessels is one of the main causes of severe chronic vascular pathologies, which quite often lead to the fatal end. It is well known that the development of atherosclerosis is an inflammatory process going through several stages until the formation of an atherosclerotic plaque. The latter, due to increased instability, would come off and cause thromboembolism. Low density lipoproteins, endothelium, platelets, neutrophils, monocytes / macrophages and smooth muscle cells of the vessel wall are all active participants in the development of atherosclerosis. Thus, they trigger and carry out the process by forming a platelet thrombus on the surface of the ulcerated calcified atherosclerotic plaque. In the recent time interest in the role of platelets in inflammatory processes has grown immensely, first of all due to their ability to interact with cells participating in different stages of atherosclerosis development through adhesion, formation of aggregations, the exchange of exovesicles and microparticles, as well as through the mutually increasing secretion of cytokines, chemokines, growth factors and other chemical mediators. This review is devoted to the role of platelets in the formation and regulation of the multicellular ensemble and also local cell modules specific for each stage of atherosclerosis development.

Assessment of Carotid Plaque Stability Using Contrast-Enhanced Ultrasound and Its Correlation With the Expression of CD147 and MMP-9 in the Plaque.

This study aims to investigate the correlation between the enhancement degree of contrast-enhanced ultrasound (CEUS) and the expression of CD147 and MMP-9 in carotid atherosclerotic plaques in patients with carotid endarterectomy and evaluate the diagnostic efficacy of CEUS using pathological results as the gold standard. Thirty-eight patients who underwent carotid endarterectomy (CEA) for carotid stenosis in the Department of Neurovascular Surgery of the Second People’s Hospital of Shenzhen from July 2019 to June 2020 were selected. Preoperatively, two-dimensional (2D) ultrasound scan was performed on all patients to assess the characteristics of the plaque and degree of stenosis, and CEUS was used to evaluate the surface morphology of the plaque and the distribution of neovascularization. Postoperatively, pathological sections and immunohistochemical analysis of CD147 and MMP-9 levels in the plaque were performed on the stripped plaque tissue, and the results were analyzed against the CEUS grading and pathological results. Among the 38 patients, pathological results showed that 10 and 28 were in the stable and vulnerable plaque groups, respectively. There were more smokers in the vulnerable plaque group than in the stable plaque group, with higher intraplaques CD147 and MMP-9. The difference in ultrasound plaque surface morphology grading and CEUS grading between the two groups was statistically significant. There was no significant difference in age, sex, incidence of complications such as hypertension, diabetes, and coronary heart disease between the two groups. CD147 was higher in the CEUS grade IV group than in the grades I (P = 0.040) and II (P = 0.010) groups. MMP-9 was higher in the CEUS grade IV group than in the grade II group (P = 0.017); MMP-9 was higher in the grade III group than in the grade II group (P = 0.015). Intraplaque contrast enhancement intensity was positively correlated with CD147 (r = 0.462, P = 0.003) and MMP-9 (r = 0.382, P = 0.018) levels. There was moderate consistency between the assessment of plaque vulnerability by 2D-ultrasound and by histopathological hematoxylin-eosin (HE) (kappa = 0.457, P > 0.05). 2D diagnosis of vulnerable plaque had a sensitivity of 85.7%, a specificity of 60.0%, a positive predictive value of 85.7%, a negative predictive value of 60.0%, and an accuracy of 78.0%. There was a strong consistency between the assessment of plaque vulnerability by CEUS and histopathological HE (kappa = 0.671, P < 0.01). CEUS had a sensitivity of 89.2%, a specificity of 80.0%, a positive predictive value of 92.6%, a negative predictive value of 72.7%, and an accuracy of 86.8% for the diagnosis of vulnerable plaques; CEUS is a reliable, non-invasive test that can show the distribution of neovascularization within vulnerable plaques, evaluate the vulnerability and risk of intraplaque hemorrhage, with a high consistency with pathological findings. The degree of intraplaque enhancement and the levels of CD147 and MMP-9 in the tissue were positively correlated.

Diverse ultrastructural landscape of atherosclerotic endothelium

Background and aimsThe endothelium plays a major role in atherosclerosis, yet the endothelial plaque surface is a largely uncharted territory. Here we hypothesize that atherosclerosis-driven remodeling of the endothelium is a dynamic process, involving both damaging and regenerative mechanisms. MethodsUsing scanning electron microscopy (SEM) and immuno-SEM, we studied endothelial junction ultrastructure, endothelial openings and immune cell-endothelium interactions in eight apoe−/− mice and two human carotid plaques. ResultsThe surface of early mouse plaques (n = 11) displayed a broad range of morphological alterations, including junctional disruptions and large transcellular endothelial pores with the average diameter between 0.6 and 3 μm. The shoulder region of advanced atherosclerotic lesions (n = 7) had a more aggravated morphology with 8 μm-size paracellular openings at two-fold higher density. In contrast, the central apical surface of advanced plaques, i.e., the plaque body (n = 7), displayed endothelial normalization, as shown by a significantly higher frequency of intact endothelial junctions and a lower incidence of paracellular pores. This normalized endothelial phenotype correlated with low immune cell density (only 5 cells/mm2).The human carotid plaque surface (n = 2) displayed both well-organized and disrupted endothelium with similar features as described above. In addition, they were accompanied by extensive thrombotic areas. ConclusionsOur study unveils the spectrum of endothelial abnormalities associated with the development of atherosclerosis. These were highly abundant in early lesions and in the shoulder region of advanced plaques, while normalized at the advanced plaque's body. Similar endothelial features were observed in human atherosclerotic plaques, underlining the versatility of endothelial transformations in atherosclerosis.

Reflectance Transformation Imaging (RTI) Investigation of Engraved Chalk Plaques from the Stonehenge Region

Newly discovered and previously documented Late Neolithic chalk plaques from the Stonehenge locality have been subjected to new, non-invasive techniques which allow access to previously unseen elements of archaeological evidence. The application of these methods – involving Reflectance Transformation Imaging (RTI) and Polynomial Texture Mapping (PTM) – has revealed detail of the surface preparation and allowed methods and sequence of the compositions to be unpicked, clarifying their complexities. The results reveal a range of approaches to the compositions, some of which demonstrate planning, order, and intention while others include less systematic, rapidly executed sketches. Investigations of lines and surfaces have been made, supplemented by preliminary studies of replicated test pieces, to examine potential implements used in their creation and remark on plaque biographies and surface attrition following manufacture. Furthermore, detail revealed by RTI provides indications of the orientations in which some of the plaques should be viewed and – in one instance – suggests a ‘reflected’ element that may not be entirely abstract. Results from improved radiocarbon determinations place the plaques in the early part of the 3rd millennium bc which, together with identification of individual motifs, allows the plaques and the designs to be reconsidered within the corpus of Neolithic art in the British Isles.

Combined Assessment of Elevated Plasma Lipoprotein-Associated Phospholipase A2 and Plaque Enhancement Improved Accuracy in the Risk of Acute Ischemic Stroke in Patients with Intracranial Artery Stenosis

PurposeWe evaluated the relationship between plasma lipoprotein-associated phospholipase A2 (Lp-PLA2) concentration and plaque characteristics in patients with intracranial artery stenosis and their clinical relevance in acute ischemic stroke. MethodsEighty-seven patients with intracranial atherosclerotic stenosis (66 males, 21 females) were retrospectively enrolled. Plasma Lp-PLA2 concentration was measured, and vessel wall magnetic resonance imaging (VW-MRI) was used to determine intracranial vascular stenosis and plaque characteristics, including plaque enhancement, surface morphology, and T1 hyperintensity. Binary logistic regression was used to evaluate the relationship between Lp-PLA2 concentration and plaque characteristics of intracranial artery after adjusting for demographic and confounding factors and to assess their diagnostic efficacy for the risk of acute ischemic stroke. ResultsAfter adjustment for demographic, medication and related lipid factors, Lp-PLA2 elevation was associated with plaque enhancement (odds ratio [OR]=12.7, 95% confidence interval [CI] 2.51–64.82, P=0.002) and surface irregularity (OR=2.9, 95% CI 1.06–7.98, P=0.038). Both Lp-PLA2 elevation (OR=8.8, 95% CI 1.64–47.72, P=0.011) and plaque enhancement (OR=34.3, 95% CI 5.88–200.4, P=0.001) were associated with acute ischemic stroke. Receiver operating characteristic curve analysis showed that the area under the curve for Lp-PLA2 concentration and plaque enhancement combined in the diagnosis of acute ischemic stroke was 0.884, significantly higher than that for Lp-PLA2 concentration (0.724) and plaque enhancement (0.794) alone. ConclusionElevated Lp-PLA2 is associated with plaque enhancement and plaque surface irregularity. Combined assessment of Lp-PLA2 concentration and plaque enhancement is of greater diagnostic value for the risk of acute ischemic stroke in patients with intracranial artery stenosis.

Pro-oxidant activity of biocompatible catechin stabilizer during photooxidation of polyolefins

Polymer plaques made of high-density polyethylene (HDPE) or cycloolefin copolymer (COC) were stabilized with natural phenolic stabilizer (+)-catechin (CAT) and aged using accelerated weathering technique (WOM; accelerated photooxidation). The efficiency of the phenolic stabilizer was compared with a well-established hindered amine stabilizer (HAS) Tinuvin®770 (Tin770). In pursuit of the stabilization and identification of short-living radicals generated in the process of photooxidation of the polymers, a spin trapping agent 2,4,6-tri-tert-butylnitrosobenzene (TTBNB) was added to selected samples. Profiles of oxidation products and crystallinity inside the HDPE plaques were determined by IR microspectroscopy, oxidation products in COC copolymers were identified using ATR spectroscopy, concentration profiles of radicals generated inside polymer plaques during WOM exposure were determined by ESRI, the changes of local mechanical properties at the surface of polymer plaques were characterized using microindentation hardness testing (MHI), and the surface morphology changes were studied by light and/or scanning electron microscopy. All methods are in accordance with the conclusion that the natural phenolic stabilizer CAT exhibited pro-oxidant activity during accelerated photooxidation of both polymers, i.e. higher concentration of oxidation products, bigger changes of local mechanical properties and/or more microcracks on the exposed surfaces in comparison with non-stabilized systems and systems stabilized with Tin770.

Plaque Removal Efficacy of Three Cleaning Methods for Removable Orthodontic Appliances: A Crossover Randomized Clinical Trial.

The mechanical plaque removal methods of removable orthodontic appliances (ROAs) may damage the appliance surface and may not effectively eliminate the entire microbial plaque. This study aimed to compare the efficacy of brushing + denture cleanser tablets, brushing + propolis mouthwash and brushing only for plaque removal from each orthodontic appliance surface. This crossover randomized clinical trial evaluated 32 patients between 7-15 years with ROAs. The patients were randomly assigned to three groups of brushing (control), brushing + denture cleanser tablets (intervention group 1), and brushing + propolis mouthwash (intervention group 2). The plaque removal methods were switched among the groups during three 1-month periods. One month after practicing a certain protocol, the plaque disclosing agent was applied on the surface of the appliance. The photographs of appliances were analyzed by Image J software to calculate the surface area occupied by the residual microbial plaque. The ratio difference of residual plaque surface area to the surface area of the entire appliance was significant between the intervention group1 and control group (p<0.001), while it was not significant in intervention group 2 and control group (p=0.105). Also, this difference between the intervention group1 and 2 was statistically significant (p<0.001). Simultaneous use of toothbrush with denture cleanser tablets decreased the microbial biofilm on the surface of ROAs, compared with brushing alone. Thus, it seems that the use of denture cleaning tablets may be suitable for effective cleaning of ROAs.

The Course of Carotid Plaque Vulnerability Assessed by Advanced Neurosonology.

Background: Carotid artery atherosclerosis is a major risk factor for ischemic stroke. This risk is related to plaque vulnerability and is characterized by plaque morphology, intraplaque neovascularization, and cerebral microembolization. Advanced neurosonology can identify vulnerable plaques and aid in preventing subsequent stroke. We aimed to assess the time course of cerebral microembolization and intraplaque neovascularization during 6 months of follow-up and to explore the utility of advanced neurosonology in patients with acute cerebral ischemia.Methods: Fifteen patients with acute cerebral ischemia and carotid artery plaques underwent comprehensive extra- and intracranial ultrasound examinations, including microemboli detection and contrast-enhanced ultrasound. The examinations were repeated after 3 and 6 months.Results: We examined 28 plaques in 15 patients. The ultrasonographic features of plaque vulnerability were frequent in symptomatic and asymptomatic plaques. There were no significant differences in stenosis degree, plaque composition, plaque surface, neovascularization, or cerebral microembolization between symptomatic and asymptomatic plaques, but symptomatic plaques had a higher number of vulnerable features. None of the patients had recurrent clinical stroke or transient ischemic attack during the follow-up period. We observed a decrease in cerebral microembolization at 6 months, but no significant change in intraplaque neovascularization.Conclusions: In patients with acute cerebral ischemia and carotid artery plaques, cerebral microembolization decreased during 6 months of follow-up, indicating plaque stabilization.Clinical Trial Registration:ClinicalTrial.gov, identifier NCT02759653.

Reversal of Root Caries with Casein Phosphopeptide-Amorphous Calcium Phosphate and Fluoride Varnish in Xerostomia

Different formulas of topical fluoride have been used to manage root carious lesions. This clinical trial aimed to investigate the efficacy of a dental varnish containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and fluoride compared with fluoride alone in reversing/arresting root caries in xerostomic patients over 1 year. A total of 80 patients (age range 45–92 years) with primary root caries (n = 184 root carious lesions) and unstimulated salivary flow rate of <0.2 mL/min were randomly allocated to receive either dental varnish containing CPP-ACP and 5% fluoride (group 1: MI varnish; GC, Japan) (n = 41, 83 lesions), or dental varnish with 5% fluoride alone (group 2: NUPRO White; Dentsply, USA) (n = 39, 101 lesions). Clinical assessments with Severity Index (SI) for root caries, DIAGNOdent measurements, and varnish application were carried out at baseline, 3, 6, and 12 months. Standard oral hygiene instructions with 1,450 ppm fluoride toothpastes were provided for both groups. After 3 months, 63.9% (n = 46) of root caries in group 1 became hard (SI: 0) compared with 39.3% (n = 35) in group 2 (p < 0.01). After 6 and 12 months, the differences in SI were insignificant (group 1, n = 60, 83.3%) (group 2, n = 66, 74.2%) (p = 0.36), and (group 1, n = 60, 89.6%) (group 2, n = 67, 81.7%, n = 1 soft, 1.2%) (p = 0.29), respectively. In both groups, noncavitated leathery lesions were more likely to become hard when compared to the cavitated root caries. A significant decrease in plaque index, surface roughness, lesion dimension, and DIAGNOdent readings with a significant increase in lesion distance from the gingival margin was reported in both groups (p < 0.05). This study has provided evidence that fluoride dental varnish either with or without calcium and phosphate has the potential to arrest/reverse root caries, especially noncavitated lesions for patients with xerostomia.

A narrative review of plaque and brain imaging biomarkers for stroke risk stratification in patients with atherosclerotic carotid artery disease.

ObjectiveIn this narrative review, we aim to review imaging biomarkers that carry the potential to non-invasively guide stroke risk stratification for treatment optimization.BackgroundCarotid atherosclerosis plays a fundamental part in the occurrence of ischemic stroke. International guidelines select the optimal treatment strategy still mainly based on the presence of clinical symptoms and the degree of stenosis for stroke prevention in patients with atherosclerotic carotid plaques. These guidelines, based on randomized controlled trials that were conducted three decades ago, recommend carotid revascularization in symptomatic patients with high degree of stenosis versus a conservative approach for most asymptomatic patients. Due to optimization of best medical therapy and risk factor control, it is suggested that a subgroup of symptomatic patients is at lower risk of stroke and may not benefit from revascularization, whereas a selective subgroup of high-risk asymptomatic patients would benefit from this procedure.MethodsA literature search was performed for articles published up to December 2020 using PubMed, EMBASE and Scopus. Based on the literature found, change in stenosis degree and volume, plaque echolucency, plaque surface, intraplaque haemorrhage, lipid-rich necrotic core, thin fibrous cap, inflammation, neovascularization, microembolic signals, cerebrovascular reserve, intracranial collaterals, silent brain infarcts, diffusion weighted imaging lesions and white matters lesions have the potential to predict stroke risk.ConclusionsThe applicability of imaging biomarkers needs to be further improved before the potential synergistic prognostic ability of imaging biomarkers can be verified on top of the clinical biomarkers. In the future, the routine and combined assessment of both plaque and brain imaging biomarkers might help to improve optimization of treatment strategies in individual patients with atherosclerotic carotid artery disease.

Dose characteristics of Au-198 eye brachytherapy applicator: A Monte Carlo study

PurposeThe use of ocular plaques is a promising treatment option for eye melanoma brachytherapy. Although several studies have been done on various ocular plaques, little is known about the dose characterization of 198Au plaque. Materials and methodThe full mathematical model of the eye phantom, tumor, 106Ru/106Rh CCA, and 198Au plaque were simulated using the Monte Carlo MCNPX code. The dose distribution was measured in the plaque's central axis direction, and a dose profile was also measured at a distance of 2.5 mm from the plaque surface. ResultsThe findings showed that 198Au plaque has superior dosimetric characteristics than CCA plaque for tumors with a thickness of greater than 3.5 mm, while CCA plaque is better for tumors with a thickness of less than 3.5 mm. The dose to the sclera and choroid is higher in the case of CCA plaque, while the dose to the organs at risk (lens and optic nerve) is greater in the case of 198Au applicator. In the case of 198Au plaque, however, the dose to sensitive organs was within their permissible dose range. ConclusionIn the treatment of medium and large tumors, 198Au plaque is more successful than CCA plaque. It can produce a much more homogeneous lateral dose profile in the target. In the treatment of dome-shaped tumors, 198Au plaque may be more successful than CCA plaque. As a result, the tumor's shape influences the plaque type selection.

Prevalence and characteristics of atherosclerotic plaque: Left compared with right arteries and anterior compared with posterior circulation stroke

PurposeTo evaluate atherosclerotic plaque prevalence and characteristics between left and right cervicocephalic arteries and between anterior and posterior circulation stroke (ACS and PCS). MethodsThis retrospective study included 284 patients with acute ischemic stroke (199 ACS and 85 PCS) involving large-artery atherosclerosis or small-artery occlusion. We assessed atherosclerotic plaque prevalence and characteristics (plaque type, plaque surface morphology, plaque distribution, location of calcified nodules and plaque thickness) in each segment and their comparisons between left and right arteries and between ACS and PCS. ResultsThe left subclavian artery (L-SA), common carotid artery (L-CCA) and intracranial vertebral artery (L-IVA) had significantly higher prevalence of atherosclerotic plaque than the right (R) corresponding arteries (70.1% versus 59.5%, P = 0.008), (48.1% versus 28.9%, P < 0.001), (23.9% versus 16%, P = 0.018), respectively. L-SA had a higher prevalence of mixed plaque (non-calcified > calcified) (19.6% versus 16.4%) and noncalcified plaque (51.9% versus 31.7%), and a lower prevalence of calcified plaque (8.9% versus 23.3%) and mixed plaque (calcified > non-calcified) (19.6% versus 28.6%) than R-SA, P < 0.001. The distribution of plaque type in the SA and extracranial vertebral artery (EVA) were significantly different between ACS and PCS. The soft plaque thickness of SA in PCS was significantly greater than that in ACS (3.85 ± 1.27 versus 3.51 ± 1.04, P = 0.032). ConclusionsAtherosclerotic plaque prevalence and characteristics vary in different segments, sides and between ACS and PCS. These differences should be noted during plaque diagnosis.

Fibrin Clot Properties in Atherosclerotic Vascular Disease: From Pathophysiology to Clinical Outcomes.

Fibrin is a major component of thrombi formed on the surface of atherosclerotic plaques. Fibrin accumulation as a consequence of local blood coagulation activation takes place inside atherosclerotic lesions and contributes to their growth. The imbalance between thrombin-mediated fibrin formation and fibrin degradation might enhance atherosclerosis in relation to inflammatory states reflected by increased fibrinogen concentrations, the key determinant of fibrin characteristics. There are large interindividual differences in fibrin clot structure and function measured in plasma-based assays and in purified fibrinogen-based systems. Several observational studies have demonstrated that subjects who tend to generate denser fibrin networks displaying impaired clot lysis are at an increased risk of developing advanced atherosclerosis and arterial thromboembolic events. Moreover, the majority of cardiovascular risk factors are also associated with unfavorably altered fibrin clot properties, with their improvement following effective therapy, in particular with aspirin, statins, and anticoagulant agents. The prothrombotic fibrin clot phenotype has been reported to have a predictive value in terms of myocardial infarction, ischemic stroke, and acute limb ischemia. This review article summarizes available data on the association of fibrin clot characteristics with atherosclerotic vascular disease and its potential practical implications.

Preclinical carotid atherosclerosis as an indicator of polyvascular disease: a narrative review.

Carotid atherosclerotic lesions are correlated with atherosclerotic deterioration of the arterial wall in other vascular territories and with cardiovascular events. The detection of pre-symptomatic carotid lesions like intima-media thickness (IMT) and asymptomatic carotid plaques is possible by non-invasive ultrasound duplex scanning. Current measurement guidelines suggest an average measurement of IMT within 10 mm of the segment of the common carotid artery. The thickening of intima-media appears in a long subclinical period of atherosclerosis. Therefore, the determination of IMT has emerged as one of the methods for determining early structural deterioration of the arterial wall. A close interrelationship was shown between IMT and risk factors of atherosclerosis, their duration, and intensity. Different studies demonstrated that increased IMT is a powerful predictor of coronary, cerebrovascular, and peripheral arterial occlusive disease and their complication. A recent meta-analysis indicated a minimal improvement in the risk estimation of cardiovascular events after adding IMT to the Framingham Risk Score. These findings influenced the latest ACC/AHA guidelines which again recommend the use of carotid IMT measurement for individual risk assessment. The presence of atherosclerotic plaques indicates that the atherosclerotic process is already ongoing. The findings of different studies are equivocal that carotid plaques independently predict cardiovascular events and improve risk predictions for coronary artery disease when added to the Framingham Risk Score. However, besides the size of plaque and grade of stenosis, the structure of plaque calcification, vascularization, lipid core, and the surface of plaques are important indicators of related risks for cardiovascular events.

Current Smoking is a Risk Factor for the Irregular Surface and Calcification of Carotid Plaque in Men.

ObjectiveTo explore whether current smoking could influence plaque characteristics and determine its correlation to the irregular surface and calcification of carotid plaque.MethodsThree hundred and seventeen patients with severe carotid atherosclerosis stenosis (SCAS) detected by color duplex flow imaging (CDFI) and confirmed by CT angiography (CTA) were recruited. The results of laboratory parameters were collected by using electronic database of the hospital. Computerized tomography (CT) scanning and high-resolution ultrasonography were performed for assessment of plaque morphology, respectively.ResultsAll enrolled smokers and non-smokers had no significant difference among all characteristics not related to smoking. CT scanning could efficiently identify the difference among enrolled smokers and non-smokers not only for the characteristics related to smoking but also the onsets of carotid plaque. Surface morphology was also efficiently detected by ultrasonography. Further ridge trace analysis showed that ultrasonography is efficient for diagnosis of calcified plaque compared with gold standard for plaque diagnosis. Further correlation analysis showed that ultrasonography parameters could offer reliable evidence for plaque scores, which was associated with age index. Ultrasonography parameters could efficiently differentiate plaque morphologies among enrolled smokers and never-smokers.ConclusionCurrent smoking was positively associated with plaque calcification onsets, and smoking cessation could efficiently attenuate such injury. High-frequency ultrasound can clearly distinguish the details of calcification with promising clinical significance for current smoking patients.

Superb Microvascular Imaging Ultrasound for Cervical Carotid Artery Stenosis for Prediction of the Development of Microembolic Signals on Transcranial Doppler during Carotid Exposure in Endarterectomy

Introduction: During exposure of the carotid arteries, embolism from the surgical site is recognized as a primary cause of neurological deficits or new cerebral ischemic lesions following carotid endarterectomy (CEA), and associations have been reported between histological neovascularization in the carotid plaque and both plaque vulnerability and the development of artery-to-artery embolism. Superb microvascular imaging (SMI) enables accurate visualization of neovessels in the carotid plaque without the use of intravenous contrast. This study aimed to determine whether preoperative SMI ultrasound for cervical carotid artery stenosis predicts the development of microembolic signals (MES) on transcranial Doppler (TCD) during exposure of the carotid arteries in CEA. Methods: Preoperative cervical carotid artery SMI ultrasound followed by CEA under TCD monitoring of MES in the ipsilateral middle cerebral artery was conducted in 70 patients previously diagnosed with internal carotid artery stenosis (defined as ≥70%). First, observers visually identified intraplaque microvascular flow (IMVF) signals as moving enhancements located near the surface of the carotid plaque within the plaque on SMI ultrasonograms. Next, regions of interest (ROI) were manually placed at the identified IMVF signals (or at arbitrary places within the plaque when no IMVF signals were identified within the carotid plaque) and the carotid lumen, and time-intensity curves of the IMVF signal and lumen ROI were generated. Ten heartbeat cycles of both time-intensity curves were segmented into each heartbeat cycle based on gated electrocardiogram findings and averaged with respect to the IMVF signal and lumen ROI. The difference between the maximum and minimum intensities (ID) was calculated based on the averaged IMVF signal (ID_IMVF) and lumen (ID_l) curves. Finally, the ratio of ID_IMVF to ID_l was calculated. Results: MES during exposure of the carotid arteries were detected in 17 patients (24%). The incidence of identification of IMVF signals was significantly greater in patients with MES (94%) than in those without (57%; p = 0.0067). The ID_IMVF/ID_l ratio was significantly greater in patients with MES (0.108 ± 0.120) than in those without (0.017 ± 0.042; p < 0.0001). The specificity and positive predictive value for the ID_IMVF/ID_l ratio for prediction of the development of MES were significantly higher than those for the identification of IMVF signals. Logistic regression analysis revealed that only the ID_IMVF/ID_l ratio was significantly associated with the development of MES (95% CI 101.1–3,628.9; p = 0.0048). Conclusion: Preoperative cervical carotid artery SMI ultrasound predicts the development of MES on TCD during exposure of the carotid arteries in CEA.

An ultrasound-derived stroke risk score to identify patients at high risk of stroke.

BackgroundTo develop an ultrasound-derived stroke risk (USR) score combining plaque stiffness, surface morphology and lumen narrowing to evaluate the risk of stroke in patients with asymptotic carotid stenosis.MethodsWe developed the USR score in a prospective study of symptomatic and asymptomatic patients with ipsilateral carotid lumen narrowing. Multivariable analysis was performed to identify parameters associated with ischemic events, and a USR score was constructed based on the observed β coefficient. The discrimination performance of the USR score was assessed using receiver operating characteristic (ROC) curves. Twenty iterations of 5-fold cross-validation were used for internal validation.ResultsWe derived the USR score (range, 0–7) by incorporating plaque stiffness (≥80 kPa, 0 points; 60–79 kPa, 1 point; 40–59 kPa, 2 points; <40 kPa, 3 points), plaque surface (smooth, 0 points; irregular, 1 point; ulcer, 2 points) and carotid stenosis (<50%, 0 points; 50–69%, 1 point; ≥70%, 2 points). After adjusting for age and sex, the odds ratio (OR) for every 1-point increase in the USR score increase was 3.3 (P<0.001). The risk of ischemic events increased with increasing USR score (P for trend <0.001). The C statistic of the USR score was 0.84 in the derivation sample and 0.82 in the validation sample.ConclusionsThe USR score to assess the risk of ischemic events in patients with carotid stenosis showed preferable discrimination ability and robustness. While external validation is warranted to prove the predictive value, this risk score could help accelerate triage decisions in similar patient populations.

Evidences for charged hydrogen bonds on surfaces bearing weakly basic pendants: The case of PMMA–ran–PDMAEMA polymeric films

Positively charging a solid surface usually confers on it a bactericidal action that increases with the charge density. The latter may be modulated by chemically specific interactions between surface groups such as charged hydrogen bonds. As this possibility has not yet been extensively investigated, we studied the surface electrolytic properties of PEG–b–(PMMA–ran–PDMAEMA)n plaques by means of contact angle titrations, ATR–FTIR spectroscopy, DFT electronic structure calculations, and Monte Carlo titration simulations. Contact angle titrations highlighted the impact that polymer composition and film preparation have on plaques surface energy upon changing the pH. Following the relative increase in IR N–H bending absorption due to ammonium formation via FTIR experiments suggested, instead, an increase of surface groups pKb compared to free DMAEMA monomers. Interestingly, the N–H bending absorption for polymers with high DMAEMA contents appeared one pH unit below than for the low DMAEMA content cases. Basing on electronic structure harmonic frequencies analysis and Monte Carlo simulations, we rationalize the difference in apparent pKb as related to a shift in N–H bending frequency (+120 cm−1) due to a more likely ammonium–amine dimerization. We predict that a sufficient density of free N–H groups ought to appear at lower pH values the higher is the DMAEMA contents.