Carotid Plaque Rupture Research Articles

Pathological Intraplaque Hemorrhage as the Gold Standard to Assess the Efficacy of Ultrasound in Predicting Vulnerable Carotid Plaque Rupture.

To assess the clinical utility of ultrasound in predicting the risk of carotid vulnerable plaque rupture using pathological intraplaque hemorrhage as the gold standard. A total of 118 patients who underwent endarterectomy due to symptomatic carotid artery stenosis were enrolled. Conventional ultrasound assessed the plaque thickness, area stenosis rate, echo, and surface morphology. Neovascularization were assessed by contrast-enhanced ultrasound (CEUS) and tracing intraplaque nonenhanced areas. According to neovascularization grade (0-4), plaques were classified as low-, intermediate-, and high risk. Fresh intraplaque hemorrhage within the pathology was adopted as the gold standard for diagnosing plaque rupture risk. Thus, we divided patients into ruptured risk and nonruptured risk groups to assess the value of crucial factors for plaque rupture risk using ultrasound. Of the 118 patients, hypertension accounted for 71.2%, hyperlipidemia 68.6%, diabetes 52.5%, and statin history 64.4%. In the rupture risk group, diabetes, smoking, and stenosis rate were significantly higher than the nonrupture risk group (P < .001); plaque thickness ≥4 mm (P > .05); and mainly hypoechoic with irregular surface morphology (P < .001), nonenhanced areas in the plaques (P < .001), and neovascularization >grade 2 (P < .001). Compared with the low-risk group, plaque rupture risk was 7.219 times higher in the medium-risk group and 18.333 times higher in the high-risk group. The kappa value of the interobserver consistency of crucial ultrasound parameters was >0.75, and the intraclass correlation coefficient was 0.919 (P < .01). Both conventional ultrasound and CEUS have significant clinical importance in the prediction of rupture risk in vulnerable carotid plaques, thereby enabling stroke risk stratification and the assessment of plaque rupture risk.

Association of Lipoprotein-associated phospholipase A2 With Carotid Intima-Media Thickness in Acute Cerebral Infarction Patients.

Lipoprotein-associated phospholipase A2 (Lp-PLA2) is an inflammatory marker associated with atherosclerotic and cardiovascular diseases. This study aimed to explore the association of Lp-PLA2 with carotid intima-media thickness (cIMT) in patients with acute ischemic stroke (AIS) and explore a threshold level to predict the risk of vulnerable plaques. This retrospective observational study included patients with AIS in the Neurology Department of our Hospital between January 2018 and December 2019. The study included 293 patients aged 65.29 ± 12.11years, including 212 males, of whom 124 had carotid intima-media thickening (42.32%). Multivariable logistic regression showed that Lp-PLA2 level was an independent risk factor for cIMT (odds ratio [OR] = 1.004, 95% confidence interval [95% CI] 1.001-1.008, P = .008). Threshold effect analysis showed that the risk of vulnerable carotid plaque occurrence increased by 2% for every 1ng/mL increase in Lp-PLA2 level with serum Lp-PLA2 levels between 157 and 279ng/mL; this increase was statistically significant (OR = 1.02, 95% CI 1.01-1.03, P < .001). Serum Lp-PLA2 is an independent risk factor for increased cIMT in patients with AIS, and a threshold Lp-PLA2 level between 157 and 279ng/mL showed a higher risk of carotid plaque rupture.

Automatic segmentation of ultrasound images of carotid atherosclerotic plaque based on Dense-UNet.

Carotid atherosclerosis plaque rupture is an important cause of myocardial infarction and stroke. The effective segmentation of ultrasound images of carotid atherosclerotic plaques aids clinicians to accurately assess plaque stability. At present, this procedure relies mainly on the experience of the medical practitioner to manually segment the ultrasound image of the carotid atherosclerotic plaque. This method is also time-consuming. This study intends to establish an automatic intelligent segmentation method of ultrasound images of carotid plaque. The present study combined the U-Net and DenseNet networks, to automatically segment the ultrasound images of carotid atherosclerotic plaques. The same test set was selected and segmented using the traditional U-Net network and the ResUNet network. The prediction results of the three network models were compared using Dice (Dice similarity coefficient), and VOE (volumetric overlap error) coefficients. Compared with the existing U-Net network and ResUNet network, the Dense-UNet network exhibited an optimal effect on the automated segmentation of the ultrasound images. The Dense-UNet network could realize the automatic segmentation of atherosclerotic plaque ultrasound images, and it could assist medical practitioners in plaque evaluation.

MicroRNAs Associated with Carotid Plaque Development and Vulnerability: The Clinician’s Perspective

Ischemic stroke (IS) related to atherosclerosis of large arteries is one of the leading causes of mortality and disability in developed countries. Atherosclerotic internal carotid artery stenosis (ICAS) contributes to 20% of all cerebral ischemia cases. Nowadays, atherosclerosis prevention and treatment measures aim at controlling the atherosclerosis risk factors, or at the interventional (surgical or endovascular) management of mature occlusive lesions. There is a definite lack of the established circulating biomarkers which, once modulated, could prevent development of atherosclerosis, and consequently prevent the carotid-artery-related IS. Recent studies emphasize that microRNA (miRNA) are the emerging particles that could potentially play a pivotal role in this approach. There are some research studies on the association between the expression of small non-coding microRNAs with a carotid plaque development and vulnerability. However, the data remain inconsistent. In addition, all major studies on carotid atherosclerotic plaque were conducted on cell culture or animal models; very few were conducted on humans, whereas the accumulating evidence demonstrates that it cannot be automatically extrapolated to processes in humans. Therefore, this paper aims to review the current knowledge on how miRNA participate in the process of carotid plaque formation and rupture, as well as stroke occurrence. We discuss potential target miRNA that could be used as a prognostic or therapeutic tool.

A pro-inflammatory and fibrous cap thinning transcriptome profile accompanies carotid plaque rupture leading to stroke

Atherosclerotic plaque rupture is the etiology of ischemic stroke and myocardial infarction. The molecular mechanisms responsible for rupture remain unclear, in part, due to the lack of data from plaques at the time of rupture. Ribosome-depleted total RNA was sequenced from carotid plaques obtained from patients undergoing carotid endarterectomy with high-grade stenosis and either (1) a carotid-related ischemic cerebrovascular event within the previous 5 days ('recently ruptured,' n = 6) or (2) an absence of a cerebrovascular event ('asymptomatic,' n = 5). Principal component analysis confirmed plaque rupture was responsible for the greatest percentage of the variability between samples (23.2%), and recently ruptured plaques were enriched for transcripts associated with inflammation and extracellular matrix degradation. Hierarchical clustering achieved differentiation of the asymptomatic from the recently ruptured plaques. This analysis also found co-expression of transcripts for immunoglobulins and B lymphocyte function, matrix metalloproteinases, and interferon response genes. Examination of the differentially expressed genes supported the importance of inflammation and inhibition of proliferation and migration coupled with an increase in apoptosis. Thus, the transcriptome of recently ruptured plaques is enriched with transcripts associated with inflammation and fibrous cap thinning and support further examination of the role of B lymphocytes and interferons in atherosclerotic plaque rupture.

Carotid Plaque Characterization Using Dual‐Energy Computed Tomography: Predicting Imminent Ipsilateral Ischemic Stroke in 30 Days

Background Despite progress in noninvasive means for visualizing and characterizing carotid plaque morphology, current clinical practice and AHA/ASA guidelines do not employ any plaque characteristics in deciding whether a patient should undergo carotid endarterectomy. Our objective is to evaluate the utility of dual‐energy computed tomography imaging characteristics of the carotid plaques to differentiate between the stable and unstable plaques and to predict subsequent ipsilateral ischemic stroke within 30 days. Methods In this retrospective case‐controlled study, 1185 consecutive neck computed tomography angiograms from November 2017 to October 2019 were included. In this cohort, 14 patients who experienced acute ischemic strokes caused by carotid plaque rupture within 30 days were identified and analyzed. Forty‐two patients who did not suffer an ischemic stroke but had matched risk factors were selected as control. Univariable and multivariate logistic regressions were used to develop a predictive model. Through a similar retrospective review of 483 stroke patients from November 2019 to October 2020, an independent test data set of 60 patients (15:45) was identified and used to assess the predictive performance of the model. Results In the univariable models, the plaque thickness (odds ratio [OR],1.59; 95% CI, 1.12–2.24; P =0.009), degree of stenosis (OR, 1.05; 95% CI, 1.02–1.09; P =0.002), plaque ulceration (OR, 20.00; 95% CI, 3.42–116.80; P =0.001), and intraplaque hemorrhage (OR, 7.22; 95% CI, 1.45–35.93; P =0.016) showed significant association with a subsequent stroke. Patent luminal diameter (OR, 0.62; 95% CI, 0.45–0.85; P =0.003) and maximal external diameter (OR, 0.70; 95% CI, 0.50–0.99; P =0.046) were inversely associated with a subsequent stroke. The final predictive model derived from multiple logistic regression included patent luminal diameter, maximal external diameter, degree of stenosis, plaque ulceration, and intraplaque hemorrhage. On the independent test data set, the model showed high specificity (84%) and negative predictive value (90%) with moderate sensitivity (73%) and positive predictive value (61%). The overall accuracy was 82%. Conclusions Dual‐energy computed tomography imaging features of carotid plaque may aid in prediction of a subsequent ipsilateral ischemic stroke within 30 days following the imaging study. Such information may guide the clinical management of vulnerable plaque.

Preliminary study on the differentiation of vulnerable carotid plaques via analysis of calcium content and spectral curve slope by using gemstone spectral imaging.

Growing evidence indicates that vulnerable carotid plaque rupture is an important cause of stroke. However, the role of novel gemstone spectral imaging (GSI) in the assessment of vulnerable carotid plaques has remained to be sufficiently explored. Therefore, the aim of the present study was to provide a comprehensive evaluation of carotid atherosclerotic plaques using both GSI imaging biomarkers and serological biomarkers, and further explore their possible roles in the atherogenic process. The present study analyzed GSI data, including calcium content of carotid atherosclerotic plaques and spectral curve slope, as well as serum high-sensitivity C-reactive protein (Hs-CRP) and monocyte chemotactic protein-1 (MCP-1) levels in patients with a carotid atherosclerotic plaque using GSI-computed tomographic angiography and immunoturbidimetry. Patients with unstable plaque exhibited a significantly lower calcium content and higher spectral curve slope than those of the stable plaque group. In addition, patients with unstable plaque exhibited an increase in Hs-CRP and MCP-1 levels compared with those of the stable plaque and normal control groups. The alteration in GSI calcium content and spectral curve slope reflects a close link between calcification and plaque instability, while aberrant Hs-CRP and MCP-1 expression are involved in the formation or development of vulnerable plaques. Taken together, the present results strongly support the feasibility of using these serological and newly identified imaging parameters as multiple potential biomarkers relevant to plaque vulnerability or stroke progression.

Interferon regulatory factor-5-dependent CD11c+ macrophages contribute to the formation of rupture-prone atherosclerotic plaques.

AimsInflammation is a key factor in atherosclerosis. The transcription factor interferon regulatory factor-5 (IRF5) drives macrophages towards a pro-inflammatory state. We investigated the role of IRF5 in human atherosclerosis and plaque stability.Methods and resultsBulk RNA sequencing from the Carotid Plaque Imaging Project biobank were used to mine associations between major macrophage associated genes and transcription factors and human symptomatic carotid disease. Immunohistochemistry, proximity extension assays, and Helios cytometry by time of flight (CyTOF) were used for validation. The effect of IRF5 deficiency on carotid plaque phenotype and rupture in ApoE−/− mice was studied in an inducible model of plaque rupture. Interferon regulatory factor-5 and ITGAX/CD11c were identified as the macrophage associated genes with the strongest associations with symptomatic carotid disease. Expression of IRF5 and ITGAX/CD11c correlated with the vulnerability index, pro-inflammatory plaque cytokine levels, necrotic core area, and with each other. Macrophages were the predominant CD11c-expressing immune cells in the plaque by CyTOF and immunohistochemistry. Interferon regulatory factor-5 immunopositive areas were predominantly found within CD11c+ areas with a predilection for the shoulder region, the area of the human plaque most prone to rupture. Accordingly, an inducible plaque rupture model of ApoE−/−Irf5−/− mice had significantly lower frequencies of carotid plaque ruptures, smaller necrotic cores, and less CD11c+ macrophages than their IRF5-competent counterparts.ConclusionUsing complementary evidence from data from human carotid endarterectomies and a murine model of inducible rupture of carotid artery plaque in IRF5-deficient mice, we demonstrate a mechanistic link between the pro-inflammatory transcription factor IRF5, macrophage phenotype, plaque inflammation, and its vulnerability to rupture.

CircRNA‑0006896‑miR1264‑DNMT1 axis plays an important role in carotid plaque destabilization by regulating thebehavior of endothelial cells in atherosclerosis.

Atherosclerosis (AS) is a chronic inflammatory disease of the vascular wall with multiple causes. AS is the primary pathological basis of cardiovascular disease and stroke. Moreover, carotid plaque rupture and thrombus formation are the main causes of ischemic stroke. Therefore, understanding the formation of carotid plaques may help improve the prediction and prevention of cardiovascular and cerebrovascular events. Endothelial cell dysfunction results in re-endothelialization and angiogenesis in atherosclerotic plaques, thus promoting plaque destabilization. The aim of the present study was to evaluate the effect of circular RNA (circRNA) molecules in serum exosomes (serum-Exos) from patients with stable plaque atherosclerosis (SA) and unstable/vulnerable plaque atherosclerosis (UA). Specifically, the effect of circRNA on human umbilical vein endothelial cell (HUVEC) behavior and the mechanisms underlying plaque destabilization in AS were evaluated. Serum-Exos were isolated, then identified using transmission electron microscopy, nanoparticle tracking analysis and western blotting. The serum-Exo-circRNA expression profile of patients with SA or UA was investigated using a circRNA array. The relationship between circRNA-006896 in serum-Exos and biochemical parameters of patients with SA and UA were analyzed using Spearman's correlation. In addition, HUVECs were incubated with serum-Exos for in vitro functional assays. The present study demonstrated that circRNAs expression profiles in SA and UA serum-Exos were significantly different, indicating a potential role for circRNAs in carotid plaque destabilization. The expression of circRNA-0006896 was positively correlated with triglyceride, low-density lipoprotein cholesterol (LDL-C) and C-reactive protein levels, and negatively correlated with albumin levels in patients with UA. However, circRNA-0006896 expression was positively correlated with LDL-C in patients with SA. Using bioinformatic analysis, a competing endogenous RNA (ceRNA) network was selected to study the regulatory roles of circRNA-0006896 in serum-Exos. Additionally, in HUVECs treated with serum-Exos derived from patients with UA, the expression of circRNA-0006896 in HUVECs was upregulated. This was accompanied by decreased expression of microRNA-1264 and SOCS3, increased levels of DNMT1 and phosphorylated STAT3. HUVEC proliferation and migration were significantly increased in the UA group, compared with the mock and SA groups. This finding indicates that the circRNA-0006896-miR-1264-DNMT1 axis plays an important role in carotid plaque destabilization by regulating the behavior of endothelial cells. Moreover, it suggests that circRNA-0006896 may represent a therapeutic target for controlling JNK/STAT3 signaling in HUVECs. Thus, this study may provide insight on potential interventions against vulnerable plaque formation in patients with AS.

Analysis of MicroRNAs Associated With Carotid Atherosclerotic Plaque Rupture With Thrombosis.

Atherosclerosis is a progressive vascular wall inflammatory disease, and the rupture of atherosclerotic vulnerable plaques is the leading cause of morbidity and mortality worldwide. This study intended to explore the potential mechanisms behind plaque rupture and thrombosis in ApoE knockout mice. The spontaneous plaque rupture models were established, and left carotid artery tissues at different time points (1-, 2-, 4-, 6-, 8-, 12-, and 16-week post-surgery) were collected. By the extent of plaque rupture, plaque was defined as (1) control groups, (2) atherosclerotic plaque group, and (3) plaque rupture group. Macrophage (CD68), MMP-8, and MMP-13 activities were measured by immunofluorescence. Cytokines and inflammatory markers were measured by ELISA. The left carotid artery sample tissue was collected to evaluate the miRNAs expression level by miRNA-microarray. Bioinformatic analyses were conducted at three levels: (2) vs. (1), (3) vs. (2), and again in seven time series analysis. The plaque rupture with thrombus and intraplaque hemorrhage results peaked at 8 weeks and decreased thereafter. Similar trends were seen in the number of plaque macrophages and lipids, the expression of matrix metalloproteinase, and the atherosclerotic and plasma cytokine levels. MiRNA-microarray showed that miR-322-5p and miR-206-3p were specifically upregulated in the atherosclerotic plaque group compared with those in the control group. Meanwhile, miR-466h-5p was specifically upregulated in the plaque rupture group compared with the atherosclerotic plaque group. The highest incidence of plaque rupture and thrombosis occurred at 8 weeks post-surgery. miR-322-5p and miR-206-3p may be associated with the formation of atherosclerotic plaques. miR-466h-5p may promote atherosclerotic plaque rupture via apoptosis-related pathways.

Superficial Calcification With Rotund Shape Is Associated With Carotid Plaque Rupture: An Optical Coherence Tomography Study.

Background: Plaque rupture is an important etiology for symptomatic carotid stenosis. The role of calcification in the plaque vulnerability has been controversial. We aimed to detect the geometric features of calcifications in carotid plaque and to examine its association with plaque rupture.Methods: Optical coherence tomography assessment of carotid plaque was performed in 88 patients. Calcification shape was evaluated through quantitative measurements of the long and short axis, area size, circumference, calcification arc, and longitudinal length. Calcification location was analyzed through the distance to the lumen. Furthermore, we developed idealized fluid-structure interaction models to investigate the association of calcification shape and plaque stress.Results: A total of 33 ruptured plaques and 30 non-ruptured plaques were recognized. Ruptured plaques had more multiple calcifications and protruded calcifications. The calcifications in the ruptured plaques displayed a remarkably lower long-axis/short-axis (L/S) ratio than in the non-ruptured plaques (p = 0.001). We classified calcification shape into crescentic calcification (L/S > 2.5) and rotund calcification (L/S ≤ 2.5). Rotund-shaped calcifications were more common in ruptured plaques than in non-ruptured plaques (p = 0.02). Superficial calcifications with minimal distance to the lumen ≤ 50 μm accounted for 79.4% of all calcifications in the ruptured plaques, and only 7.7% in the non-ruptured plaques (p < 0.001). Biomechanical analysis showed that the plaque with rotund-shaped calcification developed 7.91-fold higher von Mises stress than the plaque with crescentic calcification.Conclusions: Superficial calcifications and rotund-shaped calcifications are associated with carotid plaque rupture, suggesting that calcification location and shape may play a key role in plaque vulnerability.

Evaluation of Carotid Plaque Rupture and Neovascularization by Contrast-Enhanced Ultrasound Imaging: an Exploratory Study Based on Histopathology.

A significant portion of ischemic stroke is on account of emboli caused by fibrous cap rupture of vulnerable plaque with intraplaque neovascularization as a significant triggering factor to plaque vulnerability. Contrast-enhanced ultrasound (CEUS) could offer detailed information on plaque surface and intraplaque microvascular. This study aims to comprehensively assess the value of CEUS for the detection of plaque rupture and neovascularization in histologically verified plaques that had been removed from the patients who had undergone carotid endarterectomy (CEA). Fifty-one consecutive subjects (mean age, 67.0 ± 6.5years; 43 [84.3%] men) scheduled for CEA were recruited. Standard ultrasound and CEUS were performed prior to surgery. Based on the direction of the contrast agents that diffuse within the plaques, plaques were divided as "inside-out" direction (contrast agents diffuse from the artery lumen towards the inside of the plaque) and non-inside-out direction. Plaque enhancement was assessed by using a semi-quantitative grading scale (grade 1: no enhancement; grade 2: moderate enhancement; grade 3: extensive enhancement). Plaques were evaluated for histopathologic characteristics according to Oxford Plaque Study (OPS) standard postoperative. Intraplaque neovascularization as manifested by the appearance of CD34-positive microvessels was characterized in terms of microvessel density (MVD), microvessel area (MVA), and microvessel shape (MVS). In 51 plaques, the sensitivity, specificity, positive, and negative predictive values of contrast agent inside-out direction diffusion for the detection of plaque fibrous cap rupture were 87.5%, 92.6%, 91.3%, and 89.3%, respectively. The incidence of cap rupture was significantly higher in contrast agent inside-out direction diffusion than non-inside-out direction diffusion (73.9% vs 25.0%, p< 0.001), and inside-out direction diffusion did exhibit higher frequency of vulnerable plaques (OPS grades 3-4) (95.7% vs 53.6%, p= 0.001). Multivariate logistic regression analysis revealed the contrast agent inside-out direction diffusion as an independent correlate to plaque rupture (OR 8.5, 95% CI 2.4-30.1, p= 0.001). With increasing plaque enhancement, plaque MVD (p< 0.001), plaque MVA (p= 0.012), and percentage of highly irregular-shaped microvessels increased (p< 0.001). Contrast agent inside-out direction diffusion could indicate plaque rupture. The increase in plaque enhancement paralleled increased, larger, and more irregular-shaped microvessels, which may suggest an increased risk of plaque vulnerability.

Assessment of mechanical indicators of carotid plaque vulnerability: Geometrical curvature metric, plaque stresses and damage in tissue fibres

Stroke is a major cause of death worldwide. The rupture of atherosclerotic carotid plaques is the leading single cause of stroke. Currently there is no accepted clinical measure to quantitatively assess the risk of carotid plaque rupture. Structural analyses of vulnerable plaques, using finite element (FE) analysis, have retrospectively found that regions of high stress tend to be the site of plaque rupture. The current study proposes a new clinical measure, based on plaque geometry, to assess the risk of carotid plaque rupture. This measure, named the weighted curvature difference, is based on the curvature of both the lumen and intima-media boundary, and the local plaque thickness. A series of idealized and realistic, 2-D and 3-D geometries are used to systematically assess this novel geometrical metric. The areas predicted to be at high risk of rupture using this geometrical metric are compared with areas of high stress, obtained from both isotropic and anisotropic material models. These results are also compared with areas in diseased carotid arteries that are predicted to have high damage accumulation in collagen fibres using a continuum damage model. Results show the new geometrical metric consistently predicts the locations of high stress in all of the vessel geometries examined. The drawbacks of using lumen curvature only as a risk measure are highlighted; particularly in the case of outward remodelled vessels. Weighted curvature difference shows great potential to be used as a metric to efficiently distinguish the rupture prone areas in a diseased vessels in a way that is independent of material properties.

In vivo carotid strain imaging using principal strains in longitudinal view

Carotid plaque rupture can result in stroke or transient ischemic attack that can be devastating for patients. Ultrasound strain imaging provides a noninvasive method to identify unstable plaque likely to rupture. Axial, lateral and shear strains in carotid plaque have been shown to be linked to carotid plaque instability. Recently, there has been interest in using principal strains, which do not depend on angle of insonification of the carotid artery for quantifying instability in plaque along the longitudinal view. In this work relationships between angle dependent axial, lateral and shear strain along with axis independent principal strains are compared. Three strain indices were defined, (1) Average Mean Strain (AMS), (2) Maximum Mean Strain (MMS) and (3) Mean Standard Deviation (MSD) to identify relationships between these five strain image types in a group of 76 in vivo patients. The maximum principal strain demonstrated the highest strain values when compared to axial strain for all patients with a linear regression slope of 1.6 and a y intercept of 2.4 percent strain for AMS. The maximum shear strain when compared to shear strain had a slope of 1.15 and a y intercept of 0.21 percent for AMS. Next, the effect of insonification angle, which is the angle subtended by the artery at the location of plaque was studied. Patients were divided into three sub groups, i.e. less than 5 degrees (n = 31), between 5 and 10 degrees (n = 24) and above 10 degrees (n = 21). The angle of insonification did not make a significant difference between the three angle groups when comparing the relationship between the angle dependent and independent strain values.

Intra-Plaque Vessels on Contrast-Enhanced Ultrasound Sonography Predict Carotid Plaque Histology

Background and Purpose: Although the echogenicity of carotid plaques on carotid enhanced ultrasound (CEUS) was reported to correlate with the historological density of intra-plaque neovessels, it is unclear whether the intra-plaque vessel size is associated with carotid plaque vulnerability. We evaluated the relationship of size of intra-plaque vessels on CEUS with carotid plaque histology. Methods: We prospectively registered patients with carotid stenosis who were hospitalized to receive carotid endarterectomy between 2012 and 2016. CEUS was performed by ultrasound specialists using a 7-MHz linear transducer (GE LOGIQ7; GE Healthcare, Milwaukee, WN, USA). Sonazoid® was used for conducting CEUS. The sizes of microbubbles inside the plaques were scored at 0, 1, 3, and 5 min after the injection of contrast agent, and were categorized according to our defined vascular score (Vas-S; 0: the effect of contrast was not recognized; 1: the microbubbles were visible, but so blurred and vague that their shape could not be recognized; 2: dot or string-like microbubbles with movement, localized in part or the whole site of the plaque). At histological examination, we simplified the modified American Heart Association classification and defined as an atherosclerotic category (Ath-cat; 1: unruptured plaque; 2: ruptured plaque; 3: healed plaque). We then assessed the correlation of Vas-S with Ath-cat, which describes the process of rupture and restoration of carotid plaques. Results: A total of 97 patients were included in this study. A higher Ath-cat was significantly associated with higher Vas-S at any time. Spearman signed-rank test indicated that Vas-S at 1 min was most strongly correlated with Ath-cat (ρ = 0.43, p = 0.001). Receiver operating curve analysis indicated that a Vas-S of 0 at 1 min was significantly associated with an unruptured plaque (area under curve [AUC] 0.72, p = 0.006), while a Vas-S of 2 at 1 min was significantly associated with a healed plaque (AUC 0.72, p = 0.001). Conclusion: Vas-S values of 0 and 2 at 1 min indicated unruptured and healed plaques respectively. Thus, a Vas-S of 1 at 1 min is an indicator of a ruptured plaque. The intra-plaque vessel size on CEUS was significantly associated with carotid plaque histology, and may predict the process of plaque rupture and restoration.

Invited commentary

Management of the patient with asymptomatic carotid disease is approaching clinical equipoise. Our current guidelines are based on decades-old randomized level I trials, the Asymptomatic Carotid Atherosclerosis Study (ACAS) and Asymptomatic Carotid Surgery Trial (ACST-1), which enrolled patients between 1983 and 2003. Since then, medical therapy has intensified, particularly with the use of statins, dual antiplatelets, and more optimal antihypertensive medicines. At the same time, carotid interventions (carotid endarterectomy and carotid artery stenting) have become safer. The current Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis (CREST-2) trial aims to answer some of these timely clinical questions.1Lal B.K. Meschia J.F. Brott T.G. Clinical need, design, and goals for the carotid revascularization and medical management for asymptomatic carotid stenosis trial.Semin Vasc Surg. 2017; 30: 2-7Crossref PubMed Scopus (20) Google Scholar Increasing evidence suggests a more benign natural history for asymptomatic carotid disease than previously thought.2Marquardt L. Geraghty O.C. Mehta Z. Rothwell P.M. Low risk of ipsilateral stroke in patients with asymptomatic carotid stenosis on best medical treatment: a prospective, population-based study.Stroke. 2010; 41: e11-e17Crossref PubMed Scopus (391) Google Scholar An analysis of the asymptomatic carotid trials, ACAS and ACST-1, suggests that only 50 to 60 strokes are prevented at 5 years per 1000 carotid endarterectomies performed for asymptomatic disease.3Naylor A.R. Which patients with asymptomatic carotid stenosis benefit from revascularization?.Curr Opin Neurol. 2017; 30: 15-21Crossref PubMed Scopus (13) Google Scholar However, clinical experience shows us that a subset of patients with moderate or severe carotid disease still progress to plaque rupture and stroke in 2018. Are there certain ultrasound characteristics that can reliably identify the asymptomatic carotid plaque at high-risk of rupture? Noninvasive imaging of plaque vulnerability remains an area of active investigation. Spanos et al associate the presence on ultrasound examination of a large juxtaluminal black area with a thin fibrous cap, a decrease in vascular smooth muscle cells, and increased macrophages, all known histologic changes of plaque vulnerability. Thinning of the fibrous cap, leading to plaque vulnerability and rupture, are events that likely occur owing to a complex interaction between local plaque and systemic inflammatory mediators, hemodynamic strain, and biomechanical forces on the plaque leading to material fatigue. Vascular smooth muscle cells volume loss and thinning of the fibrous cap likely occur owing to an array of molecular changes, which may in part be explained by a particular microRNA signature occurring both locally in the plaque and in the systemic circulation.4Bazan H.A. Hatfield S.A. O'Malley C.B. Brooks A.J. Lightell Jr., D. Woods T.C. Acute loss of mir-221 and mir-222 in the atherosclerotic plaque shoulder accompanies plaque rupture.Stroke. 2015; 46: 3285-3287Crossref PubMed Scopus (49) Google Scholar, 5Bazan H.A. Hatfield S.A. Brug A. Brooks A.J. Lightell Jr., D.J. Woods T.C. Carotid plaque rupture is accompanied by an increase in the ratio of serum circr-284 to mir-221 levels.Circ Cardiovasc Genet. 2017; 10 (doi: 10.1161/CIRCGENETICS.117.001720)Crossref PubMed Scopus (76) Google Scholar All of these changes that seem to be associated with thinning of the fibrous cap will need to be further validated in future clinical studies. Lastly, it is possible that the significant protective effects of statin therapy against cardiovascular events6Ridker P.M. Danielson E. Fonseca F.A. Genest J. Gotto Jr., A.M. Kastelein J.J. et al.Rosuvastatin to prevent vascular events in men and women with elevated c-reactive protein.N Engl J Med. 2008; 359: 2195-2207Crossref PubMed Scopus (5284) Google Scholar may be due to thickening of the atherosclerotic fibrous caps. Earlier identification of an asymptomatic patient at risk of plaque rupture could then be used to treat that patient with more intense medical therapy or with a prophylactic carotid endarterectomy (or carotid artery stenting in select cases). Can ultrasound features of plaque vulnerability, such as a juxtaluminal black area and the absence of a fibrous cap, be used to decide whether or not to intervene in a patient with asymptomatic carotid artery stenosis? Because there are no randomized studies to validate these studies, these observations are unlikely to currently be widely adopted into practice. However, this article elegantly correlates known ultrasound features with well-described histologic characteristics of plaque vulnerability. Carotid plaque noninvasive imaging will continue to evolve and help to discern the vulnerable plaque that places the patient at risk. The opinions or views expressed in this commentary are those of the authors and do not necessarily reflect the opinions or recommendations of the Journal of Vascular Surgery or the Society for Vascular Surgery. Carotid artery plaque echomorphology and its association with histopathologic characteristicsJournal of Vascular SurgeryVol. 68Issue 6PreviewThe aim of the study was to determine the association of ultrasonic texture features (severity of stenosis, grey scale median, plaque area, juxtaluminal black area [JBA], and discrete white areas) previously shown to be independent predictors for stroke with established histologic features of plaque instability. Full-Text PDF Open Archive

Correlation between serum CD147 and carotid intraplaque hemorrhage

Objective: Intraplaque hemorrhage (IPH) is one of the most important causes of ischemic stroke. The purpose of this study was to explore the association between carotid IPH and CD147, which may be the serum marker related to IPH. Methods: Serum samples were collected from 68 patients with carotid artery stenosis from April to September 2004. 3.0T MRI with the 8 channel surface coil was used to scan carotid artery. Images was processed by MRI-PlaqueView. The integrity of lipid, IPH, calcified components and fibrous cap in the plaque was analysed qualitatively and quantitatively. The correlation and difference analysis among serum CD147 and plaque components were carried out. Results: Serum CD147 level in IPH positive was higher than that in IPH negative, 5 510.1 vs 4 648.0 (P=0.04). There was no significant correlation among serum CD147 and the quantitative parameters of lipid, IPH and calcification in carotid plaque and fibrous cap rupture. Serum CD147 in patients using statins was lower than that in patients not using statins, 4 914.0 vs 5 926.7 (P<0.01). Serum total cholesterol and LDL were positively correlated with serum CD147. In patients without statin, serum CD147 had a better diagnostic value for carotid IPH (AUC=0.81, P=0.04, 95% CI 0.62-0.99). Conclusion: Serum CD147 would probably be one biomarker of IPH and shows good diagnostic value of carotid IPH in the specific population.

Differences between the Molecular Mechanisms Underlying Ruptured and Non-Ruptured Carotid Plaques, and the Significance of ABCA1.

Background and Purpose Carotid plaques are a strong risk factor for ischemic stroke, and plaque rupture poses an even higher risk. Although many studies have investigated the pathogenic mechanisms of carotid plaque formation, few have studied the differences in molecular mechanisms underlying the rupture and non-rupture of carotid plaques. In addition, since early diagnosis and treatment of carotid plaque rupture are critical for the prevention of ischemic stroke, many studies have sought to identify the important target molecules involved in the rupture. However, a target molecule critical in symptomatic ruptured plaques is yet to be identified.Methods A total of 79 carotid plaques were consecutively collected, and microscopically divided into ruptured and non-ruptured groups. Quantitative polymerase chain reaction array, proteomics, and immunohistochemistry were performed to compare the differences in molecular mechanisms between ruptured and non-ruptured plaques. Enzyme-linked immunosorbent assay was used to measure the differences in ATP-binding cassette subfamily A member 1 (ABCA1) levels in the serum.Results The expression of several mRNAs and proteins, including ABCA1, was higher in ruptured plaques than non-ruptured plaques. In contrast, the expression of other proteins, including β-actin, was lower in ruptured plaques than non-ruptured plaques. The increased expression of ABCA1 was consistent across several experiments, ABCA1 was positive only in the serum of patients with symptomatic ruptured plaques.Conclusions This study introduces a plausible molecular mechanism underlying carotid plaque rupture, suggesting that ABCA1 plays a role in symptomatic rupture. Further study of ABCA1 is needed to confirm this hypothesis.

Kinin B1 receptor as a novel, prognostic progression biomarker for carotid atherosclerotic plaques.

Stroke caused by atherosclerosis remains a leading cause of morbidity and mortality worldwide, associated with carotid plaque rupture and inflammation progression. However, the inflammatory biomarkers which aid in predicting the future course of plaques are less detailed. The present study investigated the association between plaque vulnerable and inflammatory biomarkers using blood and plaque specimens. Carotid plaque specimens were obtained from 80 patients following stroke, 14 patients suffering from transient ischaemic attack and 17 asymptomatic patients that underwent carotid endarterectomy. To assess changes in plaque characteristics at histological levels, plaques were categorized by the time between the latest ischemic stroke and surgical intervention within 30, 30–90, 90–180 and over 180 days following stroke. Serum levels of inflammatory biomarkers interleukin (IL)-6, IL-10 and kinin B1 receptor (B1R) were measured by ELISA. Histological assessment of plaque was used to evaluate the plaque stability, progression and the inflammatory biomarker levels. Comparisons of histological characteristics demonstrated that plaques revealed an unstable phenotype following stroke within 30, 30–90 days and then remodeled into more stable plaques following stroke at 90–180 and over 180 days. By comparing the serum levels of inflammatory biomarkers, it was observed that IL-6 and B1R levels tended to decline whereas IL-10 levels increased in stroke patients from <30 days to over 180 days. Immunohistochemical analysis of IL-6, IL-10 and B1R demonstrated similar alterations in serum levels. Correlation analyses revealed that only B1R serum level was significantly correlated with histological level in patients with carotid atherosclerosis. The findings revealed that serum B1R levels may provide prognostic information and currently act as potential indicators for progression in atherosclerosis.

Circulating inflammation-resolving lipid mediators RvD1 and DHA are decreased in patients with acutely symptomatic carotid disease

BackgroundEfficient biomarkers for early prediction and diagnosis of an acutely symptomatic carotid plaque rupture event are currently lacking, impairing the ability to diagnose and treat patients with an acute plaque rupture events in a timely fashion. Resolvins are endogenous inflammation-resolving lipid mediators that are induced by inflammatory insults. We hypothesized that resolvin and other lipid profiles in sera likely mark the process towards plaque rupture. MethodsCirculating lipids associated with plaque rupture events were quantitatively profiled via targeted mediator-lipidomics using ultraperformance liquid chromatography tandem mass spectrometry in patients with acutely symptomatic and asymptomatic carotid disease. ResultsResolvin D1 (RvD1, 82 ± 11pM vs. 152 ± 17pM, p = 0.001) and docosahexaenoic acid (DHA) (0.052 ± 0.007µM versus 0.076 ± 0.008µM, p = 0.025) levels are decreased in the sera of patients presenting with an acutely symptomatic carotid plaque rupture event (n = 21) compared to patients with asymptomatic (n = 24) high-grade carotid stenosis. Circulating arachidonic acid (AA) levels, however, were higher (0.429 ± 0.046µM versus 0.257 ± 0.035µM, p < 0.01) in acutely symptomatic compared to asymptomatic carotid patients. ROC curve analysis demonstrates that the serum ratio AA:RvD1 (AUC 0.84, sensitivity 0.71, specificity 0.92) and AA:DHA (AUC 0.86, sensitivity 0.90, specificity 0.71) are biomarkers for the risk of atherosclerotic plaque rupture. ConclusionsA circulating pro-inflammatory lipid profile, characterized by high AA:RvD1 and AA:DHA, is associated with acutely symptomatic carotid disease and stroke.