Carotid Atherosclerotic Plaque Features in Patients with Acute Ischemic Stroke

Development and validation of a web-based dynamic nomogram to predict individualized risk of severe carotid artery stenosis based on digital subtract angiography

Objectives

Delays in diagnosing severe carotid artery stenosis (CAS) are prevalent, particularly in low-income regions with limited access to imaging examinations. CAS is a major contributor to the recurrence and poor prognosis of ischemic stroke (IS). This retrospective cohort study proposed a non-invasive dynamic prediction model to identify potential high-risk severe carotid artery stenosis in patients with ischemic stroke.

Methods

From July 2017 to March 2021, 739 patients with ischemic stroke were retrospectively recruited from the Department of Neurology at Liuzhou Traditional Chinese Medical Hospital. Risk factors for severe CAS were identified using the least absolute shrinkage and selection operator (LASSO) and multivariate logistic regression (MLR) methods. The model was constructed after evaluating multicollinearity. The model's discrimination was assessed using the C-statistic and area under the curve (AUC). Its clinical utility was evaluated through the decision curve analysis (DCA) and the clinical impact curve (CIC). Calibration was examined using a calibration plot. To provide individualized predictions, a web-based tool was developed to estimate the risk of severe CAS.

Results

Among the patients, 488 of 739 (66.0%) were diagnosed with severe CAS. Six variables were incorporated into the final model: history of stroke, serum sodium, hypersensitive C-reactive protein (hsCRP), C-reactive protein (CRP), basophil percentage, and mean corpuscular hemoglobin concentration (MCHC). Multicollinearity was ruled out through correlation plots, variance inflation factor (VIF) values, and tolerance values. The model demonstrated good discrimination, with a C-statistic/AUC of 0.70 in the test set. The DCA and CIC indicated that clinical decisions based on the model could benefit IS patients. The calibration plot showed strong concordance between predicted and observed probabilities. The web-based prediction model exhibited robust performance in estimating the risk of severe CAS.

Conclusion

This study identified six key risk factors for severe CAS in IS patients. In addition, we developed a web-based dynamic nomogram to predict the individual risk of severe CAS. This tool can potentially support tailored, risk-based, and time-sensitive treatment strategies.

A deep learning algorithm to identify carotid plaques and assess their stability

Background

Carotid plaques are major risk factors for stroke. Carotid ultrasound can help to assess the risk and incidence rate of stroke. However, large-scale carotid artery screening is time-consuming and laborious, the diagnostic results inevitably involve the subjectivity of the diagnostician to a certain extent. Deep learning demonstrates the ability to solve the aforementioned challenges. Thus, we attempted to develop an automated algorithm to provide a more consistent and objective diagnostic method and to identify the presence and stability of carotid plaques using deep learning.

Methods

A total of 3,860 ultrasound images from 1,339 participants who underwent carotid plaque assessment between January 2021 and March 2023 at the Shanghai Eighth People's Hospital were divided into a 4:1 ratio for training and internal testing. The external test included 1,564 ultrasound images from 674 participants who underwent carotid plaque assessment between January 2022 and May 2023 at Xinhua Hospital affiliated with Dalian University. Deep learning algorithms, based on the fusion of a bilinear convolutional neural network with a residual neural network (BCNN-ResNet), were used for modeling to detect carotid plaques and assess plaque stability. We chose AUC as the main evaluation index, along with accuracy, sensitivity, and specificity as auxiliary evaluation indices.

Results

Modeling for detecting carotid plaques involved training and internal testing on 1,291 ultrasound images, with 617 images showing plaques and 674 without plaques. The external test comprised 470 ultrasound images, including 321 images with plaques and 149 without. Modeling for assessing plaque stability involved training and internal testing on 764 ultrasound images, consisting of 494 images with unstable plaques and 270 with stable plaques. The external test was composed of 279 ultrasound images, including 197 images with unstable plaques and 82 with stable plaques. For the task of identifying the presence of carotid plaques, our model achieved an AUC of 0.989 (95% CI: 0.840, 0.998) with a sensitivity of 93.2% and a specificity of 99.21% on the internal test. On the external test, the AUC was 0.951 (95% CI: 0.962, 0.939) with a sensitivity of 95.3% and a specificity of 82.24%. For the task of identifying the stability of carotid plaques, our model achieved an AUC of 0.896 (95% CI: 0.865, 0.922) on the internal test with a sensitivity of 81.63% and a specificity of 87.27%. On the external test, the AUC was 0.854 (95% CI: 0.889, 0.830) with a sensitivity of 68.52% and a specificity of 89.49%.

Conclusion

Deep learning using BCNN-ResNet algorithms based on routine ultrasound images could be useful for detecting carotid plaques and assessing plaque instability.

The MMP-9 promoter genetic variant rs3918242, mRNA and protein expression in advanced carotid plaque tissue

BACKGROUND

The MMP-9 is a known player in atherosclerosis, yet associations of the MMP-9 -1562 C/T variant (rs3918242) with various atherosclerotic phenotypes and tissue mRNA expression are still contradictory. This study aimed to investigate the MMP-9 -1562 C/T variant, its mRNA and protein expression in carotid plaque (CP) tissue, as a risk factor for CP presence and as a marker of different plaque phenotypes (hyperechoic and hypoechoic) in patients undergoing carotid endarterectomy. The MnSOD as an MMP-9 negative regulator was also studied in relation to CP phenotypes.

METHODS AND RESULTS

Genotyping of 770 participants (285 controls/485 patients) was done by tetra-primer ARMS PCR. The MMP-9 mRNA expression in 88 human CP tissues was detected by TaqMan® technology. The protein levels of MMP-9 and MnSOD were assessed by Western blot analysis. The MMP-9 -1562 C/T variant was not recognized as a risk factor for plaque presence or in predisposing MMP-9 mRNA and protein levels in plaque tissue. Patients with hypoechoic plaques had significantly lower MMP-9 mRNA and protein levels than those with hyperechoic plaque (p = 0.008, p = 0.003, respectively). MnSOD protein level was significantly higher in hypoechoic plaque compared to hyperechoic (p = 0.039). MMP-9 protein expression in CP tissue was significantly affected by sex and plaque type interaction (p = 0.009).

CONCLUSIONS

Considering the differences of MMP-9 mRNA and protein expression in CP tissue regarding different plaque phenotypes and the observed sex-specific effect, the role of MMP-9 in human atherosclerotic plaques should be further elucidated.

CircSKA3 is Associated With the Risk of Extracranial Artery Stenosis and Plaque Instability Among Ischemic Stroke Patients

Circular RNA circSKA3 (spindle and kinetochore-related complex subunit 3) has been identified as a prognostic factor in ischemic stroke. The objective of this study was to investigate the association of circSKA3 with the risk of extracranial artery stenosis (ECAS) and plaque instability in patients with ischemic stroke. We constructed a competing endogenous RNA (ceRNA) network regulated by circSKA3 based on differentially expressed circRNAs and mRNAs between five patients and five controls. Gene Ontology (GO) analysis was performed on the 65 mRNAs within the network, revealing their primary involvement in inflammatory biological processes. A total of 284 ischemic stroke patients who underwent various imaging examinations were included for further analyses. Each 1 standard deviation increase in the log-transformed blood circSKA3 level was associated with a 56.3% increased risk of ECAS (P = 0.005) and a 142.1% increased risk of plaque instability (P = 0.005). Patients in the top tertile of circSKA3 had a 2.418-fold (P < 0.05) risk of ECAS compared to the reference group (P for trend = 0.02). CircSKA3 demonstrated a significant but limited ability to discriminate the presence of ECAS (AUC = 0.594, P = 0.015) and unstable carotid plaques (AUC = 0.647, P = 0.034). CircSKA3 improved the reclassification power for ECAS (NRI: 9.86%, P = 0.012; IDI: 2.97%, P = 0.007) and plaque instability (NRI: 36.73%, P = 0.008; IDI: 7.05%, P = 0.04) beyond conventional risk factors. CircSKA3 played an important role in the pathogenesis of ischemic stroke by influencing inflammatory biological processes. Increased circSKA3 was positively associated with the risk of ECAS and plaque instability among ischemic stroke patients.

ANRIL overexpression globally induces expression and alternative splicing of genes involved in inflammation in HUVECs

Long non‑coding (lnc)RNAs serve important cellular functions and certain lncRNAs have roles in different mechanisms of gene regulation. lncRNA‑antisense non‑coding RNA in the INK4 locus (ANRIL) affects cell inflammation; however, the potential genes underlying the inflammatory response regulated by ANRIL remain unclear. In the present study, the potential function of ANRIL in regulating gene expression and alternative splicing was assessed. ANRIL‑regulated human umbilical vein endothelial cell (HUVEC) transcriptome was obtained using high‑throughput RNA sequencing (RNA‑seq) to evaluate the potential role of ANRIL. Following plasmid transfection, gene expression profile and alternative splicing pattern of HUVECs overexpressing ANRIL were analyzed using RNA‑seq. ANRIL overexpression affected the transcription levels of genes associated with the inflammatory response, NF‑κB signaling pathway, type I interferon‑mediated signal transduction pathway and innate immune response. ANRIL regulated the alternative splicing of hundreds of genes with functions such as gene expression, translation, DNA repair, RNA processing and participation in the NF‑κB signaling pathway. Many of these genes serve a key role in the inflammatory response. ANRIL‑regulated inflammatory response may be achieved by regulating alternate splicing and transcription. The present study broadened the understanding of ANRIL‑mediated gene regulation mechanisms and clarified the role of ANRIL in mediating inflammatory response mechanisms.

Diagnostic Predictive Value of Tryptase, Serum Amyloid A and Lipoprotein-Associated Phospholipase A2 Biomarker Groups for Large Atherosclerotic Cerebral Infarction

Background

There has been a gradual trend towards younger ageing of acute cerebral infarction in recent years. Atherosclerotic plaque rupture followed by dislodgement of emboli and resulting arterial embolism is an important mechanism for the development of acute cerebral infarction. Traditional independent risk factors for cerebral infarction have received attention from clinicians, but the risk factors for large artery atherosclerotic cerebral infarction are still unclear. Various blood biomarkers have an important role in the early diagnosis of large artery atherosclerotic cerebral infarction.

Objective

To assess the diagnostic predictive value of a group of biomarkers for large artery atherosclerotic cerebral infarction.

Methods

Lipoprotein-associated phospholipase A2 (LP-PLA2), trypsin-like protein (TPS), serum amyloid A (SAA), and supersensitive C-reactive protein (hs-CRP) levels were measured in the case group (30 cases) and control group (54 cases), respectively.

Results

The differences in the general data between the two groups were not statistically significant (P > 0.05). Logistic regression and ROC curve analysis showed that Lp-PLA2, TPS, and SAA were positively associated with the diagnosis of large atherosclerotic cerebral infarction (P < 0.05). The area under the ROC curve of the multivariate model for the biomarker group reached 0.995.

Conclusion

Biomarkers are closely associated with the occurrence of large atherosclerotic cerebral infarction and can be used as clinical adjuncts for diagnosis and assessment of prognosis.

Echocardiographic epicardial fat thickness and immature granulocyte are novel inflammatory predictors of acute ischemic stroke: a prospective study

BACKGROUND

Acute ischemic stroke (AIS) is the most common type of stroke. Inflammation is the primary factor in the pathogenesis of atherosclerosis. Use of immature granulocytes (IGs) has been recommended as a new indicator of systemic inflammation. However, data on the association between echocardiographic epicardial fat tissue thickness (EFT) and IGs in patients with AIS are limited.

OBJECTIVE

To evaluate the association between the presences of IGs, epicardial fat tissue and AIS.

DESIGN AND SETTING

Prospective study in a tertiary-care university hospital in Antalya, Turkey.

METHODS

Our study included 53 AIS patients and 41 healthy controls with age and gender compatibility. Blood samples and transthoracic echocardiography of all participants were compared.

RESULTS

IG levels were significantly higher in patients with AIS than in controls (0.62 ± 0.36 versus 0.28 ± 0.02, P < 0.001). The mean EFT was 3.74 ± 0.61 mm in the control group and 6.33 ± 1.47 mm in the AIS patient group. EFT was significantly greater in AIS patients than in controls (P < 0.001). For the optimum cut-off value for IG (0.95), the area under the curve (AUC) was determined to be 0.840; sensitivity was determined to be 81.1% and specificity, 92.5%. For the optimum cut-off value for EFT (4.95 mm), the AUC was determined to be 0.953; sensitivity was determined to be 90.6% and specificity, 90%.

CONCLUSIONS

IG and echocardiographic EFT are clinical markers that can be used to predict AIS risk.

An investigation into the critical role of fibre orientation in the ultimate tensile strength and stiffness of human carotid plaque caps

The development and subsequent rupture of atherosclerotic plaques in human carotid arteries is a major cause of ischaemic stroke. Mechanical characterization of atherosclerotic plaques can aid our understanding of this rupture risk. Despite this however, experimental studies on human atherosclerotic carotid plaques, and fibrous plaque caps in particular, are very limited. This study aims to provide further insights into atherosclerotic plaque rupture by mechanically testing human fibrous plaque caps, the region of the atherosclerotic lesion most often attributed the highest risk of rupture. The results obtained highlight the variability in the ultimate tensile stress, strain and stiffness experienced in atherosclerotic plaque caps. By pre-screening all samples using small angle light scattering (SALS) to determine the dominant fibre direction in the tissue, along with supporting histological analysis, this work suggests that the collagen fibre alignment in the circumferential direction plays the most dominant role for determining plaque structural stability. The work presented in this study could provide the basis for new diagnostic approaches to be developed, which non-invasively identify carotid plaques at greatest risk of rupture. STATEMENT OF SIGNIFICANCE: Mechanical characterisation of the atherosclerotic plaque cap is of utmost importance for understanding the mechanisms that govern the rupture strength of this tissue in-vivo. Studies has shown that plaque tissue is heterogenous and comprises of many structural components, each of which exhibits a varying mechanical response. However, rupture generally is located to the plaque cap, whereby the stress exerted on this location exceeds its mechanical strength causing failure. This work shows, for the first time, that the underlying collagen fibre architecture of carotid plaque caps governs their strength and stiffness. This study shows that plaque caps with collagen fibres aligned in the predominately circumferential direction experience higher stresses and lower strains before failure while those with predominately axial fibres display the opposite trend. Furthermore, total collagen content was found not to play a dominant role in determining the mechanical response of the tissue. The present study provides critical insights into human atherosclerotic plaque tissue mechanics and offers clinically relevant insights for mechanically sensitive imaging techniques, such as strain-based ultrasound or MRI.

Clinical Utility of the Serum Level of Lipoprotein-Related Phospholipase A2 in Acute Ischemic Stroke With Cerebral Artery Stenosis

We aimed to study the clinical utility of serum lipoprotein-associated phospholipase A2 (Lp-PLA2) in acute ischemic stroke (AIS) with cerebral artery stenosis (CAS). We included 200 AIS patients and 90 healthy controls in this study. AIS patients were classified into three subgroups depending on the severity of CAS. They were also classified based on the stability of the carotid plaques. Spearman correlation analysis was performed to determine the correlation relationship between the level of Lp-PLA2 and neurologic injury. Binary logistic regression analysis was performed to determine the independent risk factors for AIS. Receiver operating characteristic (ROC) analysis was performed to assess the diagnostic value of Lp-PLA2 for AIS and for the degree of CAS. We found that the serum level of Lp-PLA2 in AIS patients was significantly higher than that in the control group. Lp-PLA2 was further identified as an independent risk factor for AIS (p = 0.001, OR = 1.057). In addition, serum Lp-PLA2 level was the highest in AIS patients with severe CAS or occlusion. Lp-PLA2 level was higher in AIS patients with unstable plaques and in AIS patients with moderate to severe neurological injury. Lp-PLA2 level was positively correlated with National Institutes of Health Stroke Scale (NIHSS) score (r = 0.335, p = 0.001). We found that the optimal cut-off value for Lp-PLA2 level was 123.365 ng/ml, at which the sensitivity and specificity for the diagnosis of ACI were 74.5 and 86.7%, respectively, and the area under ROC curve (AUC) was 0.892. Similarly, the optimal value for Lp-PLA2 level was 136.46 ng/ml, at which the sensitivity and specificity for the diagnosis of the presence of moderate to severe artery stenosis or occlusion were 79.6 and 95.2%, respectively, and the AUC was 0.938. The ROC curve indicated that serum Lp-PLA2 level has an excellent diagnostic value for AIS and severe stenosis. Based on these results we conclude that Lp-PLA2 could be a potential biomarker to complement the current imaging methods in the prediction and diagnosis of AIS. An elevated Lp-PLA2 level is also correlated with carotid plaque instability, severe neurological injury and cerebrovascular stenosis. Future longitudinal studies are needed to determine whether there is a causative relationship between Lp-PLA2 and AIS.

Evaluation of lipoprotein-associated phospholipase A2, serum amyloid A, and fibrinogen as diagnostic biomarkers for patients with acute cerebral infarction

Objective

The aim of this study was to explore the clinical values of combined detection of lipoprotein‐associated phospholipase A2 (Lp‐PLA2), serum amyloid A (SAA), and plasma fibrinogen (FIB) in the diagnosis of acute cerebral infarction (ACI).

Methods

A case‐control study including 100 hospitalized patients with ACI and 47 healthy controls was carried out. The level of Lp‐PLA2, SAA, and FIB was detected, respectively, and their clinical values were analyzed. Carotid lesions and neurological impairment were also analyzed in each patient.

Results

The level of Lp‐PLA2, SAA, and FIB in the ACI group was significantly higher than that of the controls, and the three biomarkers showed a significant positive correlation and were considered as risk factors for ACI. The area under the curve (AUC) for Lp‐PLA2, SAA, and FIB was 0.858, 0.743, and 0.672, respectively. When three biomarkers were used in combination, the AUC was 0.879. Compared with the other groups, the levels of three biomarkers in bilateral carotid plaque ACI group were all significantly higher. In addition, the level of Lp‐PLA2 and SAA in ACI patients with severe neurological impairment was also significantly higher than that of the mild‐to‐moderate group.

Conclusion

Lp‐PLA2 combined with SAA and FIB had a high clinical value for rapid diagnosis and prediction of ACI. These biomarkers were also significantly associated with the formation of bilateral carotid atherosclerotic plaques and the severe neurological impairment in ACI patients.

Association between ADAMTS7 polymorphism and carotid artery plaque vulnerability

Recent genome-wide association studies (GWAS) indicated that polymorphisms in ADAMTS7 were associated with artery disease caused by atherosclerosis. However, the correlation between the ADAMTS7 polymorphism and plaque stability remains unclear. The objective of this study was to evaluate the association between 2 ADAMTS7 variants rs3825807 and rs7173743 and ischemic stroke or atherosclerotic plaque vulnerability.This research is an observational study. Patients with ischemic stroke and normal control individuals admitted to Beijing Tiantan Hospital from May 2014 to October 2017 were enrolled. High-resolution magnetic resonance imaging was used to distinguish vulnerable and stable carotid plaques. The ADAMTS7 SNPs were genotyped using TaqMan assays on real-time PCR system. The multivariate logistic regression analyses were used to adjust for multiple risk factors between groups.Three hundred twenty-six patients with ischemic stroke (189 patients with vulnerable plaque and 81 patients with stable plaque) and 432 normal controls were included. ADAMTS7 polymorphisms of both rs7173743 and rs3825807 were associated with carotid plaque vulnerability but not the prevalence of ischemic stroke. The T/T genotype of rs7173743 [odds ratio (OR) = 1.885, 95% confidence interval (CI) = 1.067-3.328, P = .028] and A/A genotype of rs3825807 (OR = 2.146, 95% CI = 1.163-3.961, P = .013) were considered as risk genotypes for vulnerable plaque susceptibility.In conclusion, ADAMTS7 variants rs3825807 and rs7173743 are associated with the risk for carotid plaque vulnerability.

Prospective Study About the Relationship Between CEUS of Carotid Intraplaque Neovascularization and Ischemic Stroke in TIA Patients

Objective: To evaluate the relationship between contrast-enhanced ultrasonography (CEUS) of carotid intraplaque neovascularization and ischemic stroke in transient ischemic attack (TIA) patients. Methods: A total of 112 TIA patients were selected for the study. Routine carotid ultrasonic examination was performed for all the patients. CEUS was carried out for consecutive patients with plaque thicker than 2.5 mm in carotid bifurcation and follow-up for at least 24 months. The number of patients with incurrence of ischemic stroke or recurrence of TIA was obtained during the follow-up period. To detect the risk factors for incurrence of ischemic stroke or recurrence of TIA in 24 months, multivariate logistic regression analyses were performed for all the risk factors in all the selected patients. Results: Ninety-one patients underwent CEUS and were followed up at least 24 months. There were statistical differences between recurrent and non-recurrent groups about hypertension, diabetes, hyperlipemia, smoking history, family history of stroke, medication compliance, two-dimensional ultrasound, and CEUS (P < 0.05). The higher CEUS intensity in the carotid plaque was, the higher was the possibility of ischemic stroke or recurrent TIA. Multivariate logistic regression analysis showed that the CEUS characteristics of carotid plaque such as linear enhancement or diffuse enhancement were independent risk factors for ischemic stroke or recurrent TIA in TIA patients (P < 0.05). Conclusion: For carotid plaques, CEUS could evaluate the infusion mode, which could reflect the neovascularization in plaques. CEUS could predict the incurrence of ischemic stroke or recurrence of TIA in TIA patients, which is useful information when making a clinical decision.

Circulating long noncoding RNA ANRIL downregulation correlates with increased risk, higher disease severity and elevated pro-inflammatory cytokines in patients with acute ischemic stroke

BACKGROUND

To investigate the correlation of plasma lncRNA ANRIL expression with stroke risk, severity and inflammatory cytokines levels in acute ischemic stroke (AIS) patients.

METHODS

A total of 126 AIS patients and 125 controls were consecutively recruited in this case-control study. Blood samples from all participants were collected, and plasma was separated. Plasma lncRNA ANRIL expression was quantified by quantitative real-time polymerase chain reaction (qRT-PCR). Plasma tumor necrosis factor-α (TNF-α) and interleukin (IL)-1β (IL-1β), IL-6, IL-8, IL-10, and IL-17 levels were measured by enzyme-linked immunosorbent assay (ELISA). National Institutes of Health Stroke Scale (NIHSS) scores were used to assess the stroke severity in AIS patients.

RESULTS

Plasma lncRNA ANRIL expression was lower in AIS patients than in controls (P < 0.001), and the receiver operating characteristic (ROC) curve showed a good prediction value of lncRNA ANRIL for AIS risk with area under curve (AUC) of 0.759 (95% CI: 0.741-0.849). In addition, lncRNA ANRIL expression was negatively correlated with NIHSS score (r = -0.351, P < 0.001). Furthermore, while lncRNA ANRIL expression was negatively associated with hs-CRP level (r = -0.247, P = 0.005), no correlation was found between lncRNA ANRIL expression and ESR level (P = 0.619). For inflammatory cytokines, lncRNA ANRIL expression was inversely associated with TNF-α (r = -0.216, P = 0.015) and IL-6 levels (r = -0.326, P < 0.001), while it positively correlated with IL-10 level (r = 0.210, P = 0.018).

CONCLUSION

Circulating lncRNA ANRIL downregulation correlates with increased stroke risk, higher disease severity and elevated inflammation in AIS patients.