Early identification of carotid vulnerable plaque in asymptomatic patients

Metabolic score and its components are associated with carotid plaque prevalence in young adults

PURPOSE

No study has comprehensively assessed the relationship of metabolic factors including insulin resistance, hypertension, hyperuricemia, and hypercholesterolemia with the development of carotid plaque. Therefore, we constructed metabolic scores based on the above metabolic factors and examined its association with carotid plaque in young and older Chinese adults.

METHODS

This study included 17,396 participants who underwent carotid ultrasound examinations, including 14,173 young adults (<65 years) and 3,223 older adults (≥65 years). Individual metabolic score was calculated using triglyceride-glucose (TyG) index, mean arterial pressure (MAP), uric acid, and total cholesterol (TC). Logistic regression models were conducted to examine the role of metabolic score and its components in the prevalence of carotid plaque. The nonlinear relationship was examined using restricted cubic spline regression. Meanwhile, subgroup, interaction, and sensitivity analyses were conducted.

RESULTS

The multivariate logistic regression analysis showed that TyG (OR: 1.088; 95%CI: 1.046-1.132), MAP (OR: 1.121; 95%CI: 1.077-1.168), TC (OR: 1.137; 95%CI: 1.094-1.182) and metabolic score (OR: 1.064; 95%CI: 1.046-1.082) were associated with carotid plaque prevalence in young adults rather than older adults. The nonlinear association was not observed for metabolic scores and carotid plaque. Subgroup analyses showed significant associations between metabolic scores and carotid plaque prevalence in men, women, normal-weight, and overweight young adults. No interaction of metabolic score with sex and BMI were observed.

CONCLUSIONS

The results support that control of TyG, MAP, TC, and metabolic scores is a key point in preventing the prevalence of carotid plaque in the young adults.

Molecular Pathways of Vulnerable Carotid Plaques at Risk of Ischemic Stroke: A Narrative Review

The concept of vulnerable carotid plaques is pivotal in understanding the pathophysiology of ischemic stroke secondary to large-artery atherosclerosis. In macroscopic evaluation, vulnerable plaques are characterized by one or more of the following features: microcalcification; neovascularization; lipid-rich necrotic cores (LRNCs); intraplaque hemorrhage (IPH); thin fibrous caps; plaque surface ulceration; huge dimensions, suggesting stenosis; and plaque rupture. Recognizing these macroscopic characteristics is crucial for estimating the risk of cerebrovascular events, also in the case of non-significant (less than 50%) stenosis. Inflammatory biomarkers, such as cytokines and adhesion molecules, lipid-related markers like oxidized low-density lipoprotein (LDL), and proteolytic enzymes capable of degrading extracellular matrix components are among the key molecules that are scrutinized for their associative roles in plaque instability. Through their quantification and evaluation, these biomarkers reveal intricate molecular cross-talk governing plaque inflammation, rupture potential, and thrombogenicity. The current evidence demonstrates that plaque vulnerability phenotypes are multiple and heterogeneous and are associated with many highly complex molecular pathways that determine the activation of an immune-mediated cascade that culminates in thromboinflammation. This narrative review provides a comprehensive analysis of the current knowledge on molecular biomarkers expressed by symptomatic carotid plaques. It explores the association of these biomarkers with the structural and compositional attributes that characterize vulnerable plaques.

Significance of chitinase-3-like protein 1 in the pathogenesis of inflammatory diseases and cancer

Chitinase-3-like protein 1 (CHI3L1) is a secreted glycoprotein that mediates inflammation, macrophage polarization, apoptosis, and carcinogenesis. The expression of CHI3L1 is strongly upregulated by various inflammatory and immunological diseases, including several cancers, Alzheimer's disease, and atherosclerosis. Several studies have shown that CHI3L1 can be considered as a marker of disease diagnosis, prognosis, disease activity, and severity. In addition, the proinflammatory action of CHI3L1 may be mediated via responses to various proinflammatory cytokines, including tumor necrosis factor-α, interleukin-1β, interleukin-6, and interferon-γ. Therefore, CHI3L1 may contribute to a vast array of inflammatory diseases. However, its pathophysiological and pharmacological roles in the development of inflammatory diseases remain unclear. In this article, we review recent findings regarding the roles of CHI3L1 in the development of inflammatory diseases and suggest therapeutic approaches that target CHI3L1.

Combinatorial Use of Machine Learning and Logistic Regression for Predicting Carotid Plaque Risk Among 5.4 Million Adults With Fatty Liver Disease Receiving Health Check-Ups: Population-Based Cross-Sectional Study

BACKGROUND

Carotid plaque can progress into stroke, myocardial infarction, etc, which are major global causes of death. Evidence shows a significant increase in carotid plaque incidence among patients with fatty liver disease. However, unlike the high detection rate of fatty liver disease, screening for carotid plaque in the asymptomatic population is not yet prevalent due to cost-effectiveness reasons, resulting in a large number of patients with undetected carotid plaques, especially among those with fatty liver disease.

OBJECTIVE

This study aimed to combine the advantages of machine learning (ML) and logistic regression to develop a straightforward prediction model among the population with fatty liver disease to identify individuals at risk of carotid plaque.

METHODS

Our study included 5,420,640 participants with fatty liver from Meinian Health Care Center. We used random forest, elastic net (EN), and extreme gradient boosting ML algorithms to select important features from potential predictors. Features acknowledged by all 3 models were enrolled in logistic regression analysis to develop a carotid plaque prediction model. Model performance was evaluated based on the area under the receiver operating characteristic curve, calibration curve, Brier score, and decision curve analysis both in a randomly split internal validation data set, and an external validation data set comprising 32,682 participants from MJ Health Check-up Center. Risk cutoff points for carotid plaque were determined based on the Youden index, predicted probability distribution, and prevalence rate of the internal validation data set to classify participants into high-, intermediate-, and low-risk groups. This risk classification was further validated in the external validation data set.

RESULTS

Among the participants, 26.23% (1,421,970/5,420,640) were diagnosed with carotid plaque in the development data set, and 21.64% (7074/32,682) were diagnosed in the external validation data set. A total of 6 features, including age, systolic blood pressure, low-density lipoprotein cholesterol (LDL-C), total cholesterol, fasting blood glucose, and hepatic steatosis index (HSI) were collectively selected by all 3 ML models out of 27 predictors. After eliminating the issue of collinearity between features, the logistic regression model established with the 5 independent predictors reached an area under the curve of 0.831 in the internal validation data set and 0.801 in the external validation data set, and showed good calibration capability graphically. Its predictive performance was comprehensively competitive compared with the single use of either logistic regression or ML algorithms. Optimal predicted probability cutoff points of 25% and 65% were determined for classifying individuals into low-, intermediate-, and high-risk categories for carotid plaque.

CONCLUSIONS

The combination of ML and logistic regression yielded a practical carotid plaque prediction model, and was of great public health implications in the early identification and risk assessment of carotid plaque among individuals with fatty liver.

Oxidized LDL receptors: a recent update

PURPOSE OF REVIEW

LDL in its oxidized form, or 'oxLDL', is now generally acknowledged to be highly proatherogenic and to play a significant role in atherosclerotic plaque formation. Therefore, there has been increasing interest in understanding the significance of oxLDL and its receptors in different phases of atherosclerosis, leading to the accumulation of additional data at the cellular, structural, and physiological levels. This review focuses on the most recent discoveries about these receptors and how they influence lipid absorption, metabolism, and inflammation in various cell types.

RECENT FINDINGS

Two crystal structures of lectin-like oxLDL receptor-1 (LOX-1), one with a small molecule inhibitor and the other with a monoclonal antibody have been published. We recently demonstrated that the 'surface site' of LOX1, adjacent to the positively charged 'basic spine region' that facilitates oxLDL binding, is a targetable site for drug development. Further, recent human studies showed that soluble LOX-1 holds potential as a biomarker for cardiovascular disease diagnosis, prognosis, and assessing the efficacy of therapy.

SUMMARY

Receptor-mediated oxLDL uptake results in cellular dysfunction of various cell types involved in atherogenesis and plaque development. The current advancements clearly demonstrate that targeting oxLDL-LOX-1 axis may lead to development of future therapeutics for the treatment of atherosclerotic cardiovascular and cerebrovascular diseases.

Association between the triglyceride-glucose index and carotid plaque incidence: a longitudinal study

BACKGROUND

Carotid plaque and triglyceride-glucose (TyG) index are associated with insulin resistance. However, a highly debated question is whether there is an association between the TyG index and carotid plaque incidence. Thus we performed an in-depth longitudinal study to investigate the relationship between carotid plaque occurrence and the TyG index among Chinese individuals.

METHODS

Two thousand and three hundred seventy subjects (1381 males and 989 females) were enrolled and followed up for three years. The subjects were stratified into four groups based on the quartile of the TyG index at baseline. Univariate and multivariate Cox proportional hazard models were conducted to examine the role of TyG played in the carotid plaque. The strength of association was expressed as hazard ratio (HR) and 95% confidence interval (CI).

RESULTS

After three years of follow-up, 444 subjects were detected with newly formed carotid plaque. The overall 3-year cumulative carotid plaque incidence was 18.7%, and the risk of carotid plaque increased with elevated TyG index (p < 0.001). The Cox regression analysis showed that males (HR: 1.33, 95% CI: 1.10-1.61), and people with higher systolic blood pressure (HR:1.01, 95% CI: 1.01-1.02), lower high-density lipoprotein cholesterol (HR: 0.68, 95% CI: 0.50-0.93), diabetes (HR: 2.21, 95% CI: 1.64-2.97), and hypertension (HR:1.49, 95% CI: 1.23-1.81) had a significantly increased risk for the carotid plaque formation. Similar results remained in the sensitivity analysis.

CONCLUSIONS

The TyG index can be used as a dose-responsive indicator of carotid plaque in the Chinese population. Elderly males with dyslipidemia, diabetes, or hypertension should be more vigilant about their TyG index since they are susceptible to developing carotid plaque. Physicians are encouraged to monitor the TyG index to help identify and treat patients with carotid plaque at an early stage.

Abdominal Aortic Calcification Volume Is Associated with Wall Enhancement of Unruptured Intracranial Aneurysm

OBJECTIVE

Inflammatory atherosclerotic remodeling of unruptured intracranial aneurysms (UIAs) wall, which could be detected as aneurysm wall enhancement (AWE) in MR vessel wall imaging (VWI), plays a pivotal role in pathophysiology of progression to rupture. On the other hand, abdominal aortic calcification reflects the extent of systemic atherosclerosis, which in turn predicts the risk of atherosclerotic cardiovascular as well as cerebrovascular diseases. This study sought to investigate whether the abdominal aortic calcification was associated with increased wall enhancement of UIAs in VWI.

METHODS

This retrospective study reviewed subjects who underwent evaluation using 3T MR-VWI of UIAs and abdominal CT before endovascular treatments for UIAs between 2018 to 2020. Abdominal aortic calcification volume (ACV) was quantitatively measured from abdominal CT scans between renal arteries and bifurcation. The presence of AWE was correlated with patient profile, aneurysm morphology, and the ACV.

RESULTS

A total of 42 patients with 50 UIAs were included. AWE was detected in 19 (38.0%) UIAs. Maximum diameter (9.2 ± 5.0 mm vs 5.3 ± 1.5 mm, P < 0.01) and the ACV (8.2 ± 6.0 mL vs 4.7 ± 4.6 mL, P = 0.038) were significantly higher in UIAs with AWE than those without AWE.

CONCLUSIONS

The ACV was significantly associated with increased wall enhancement of UIAs. Systemic atherosclerosis might be a risk factor for the instability of UIAs. Future studies examining the effect of medications for systemic atherosclerosis on the extent of AWE in UIAs is warranted.

Identification Markers of Carotid Vulnerable Plaques: An Update

Vulnerable plaques have been a hot topic in the field of stroke and carotid atherosclerosis. Currently, risk stratification and intervention of carotid plaques are guided by the degree of luminal stenosis. Recently, it has been recognized that the vulnerability of plaques may contribute to the risk of stroke. Some classical interventions, such as carotid endarterectomy, significantly reduce the risk of stroke in symptomatic patients with severe carotid stenosis, while for asymptomatic patients, clinically silent plaques with rupture tendency may expose them to the risk of cerebrovascular events. Early identification of vulnerable plaques contributes to lowering the risk of cerebrovascular events. Previously, the identification of vulnerable plaques was commonly based on imaging technologies at the macroscopic level. Recently, some microscopic molecules pertaining to vulnerable plaques have emerged, and could be potential biomarkers or therapeutic targets. This review aimed to update the previous summarization of vulnerable plaques and identify vulnerable plaques at the microscopic and macroscopic levels.

The underlying mechanisms of cold exposure-induced ischemic stroke

Growing evidence suggests that cold exposure is to some extent a potential risk factor for ischemic stroke. At present, although the mechanism by which cold exposure induces ischemic stroke is not fully understood, some potential mechanisms have been mentioned. First, the seasonal and temperature variability of cerebrovascular risk factors (hypertension, hyperglycemia, hyperlipidemia, atrial fibrillation) may be involved. Moreover, the activation of sympathetic nervous system and renin-angiotensin system and their downstream signaling pathways (pro-inflammatory AngII, activated platelets, and dysfunctional immune cells) are also major contributors. Finally, the influenza epidemics induced by cold weather are also influencing factors that cannot be ignored. This article is the first to systematically and comprehensively describe the underlying mechanism of cold-induced ischemic stroke, aiming to provide more preventive measures and medication guidance for stroke-susceptible individuals in cold season, and also provide support for the formulation of public health policies.

Implications of the heterogeneity between guideline recommendations for the use of low dose aspirin in primary prevention of cardiovascular disease

The most recent primary cardiovascular disease (CVD) prevention clinical guidelines used in Europe, Italy, the USA, China, and South Korea differ in aspects of their approach to CVD risk assessment and reduction. Low dose aspirin use is recommended in certain high-risk patients by most but not all the countries. Assessment of traditional risk factors and which prediction models are commonly used differ between countries. The assessments and tools may not, however, identify all patients at high risk but without manifest CVD. The use of coronary artery calcium (CAC) score to guide decisions regarding primary prevention aspirin therapy is recommended only by the US primary prevention guidelines and the 2021 European Society of Cardiology guidelines. A more consistent and comprehensive global approach to CVD risk estimation in individual patients could help to personalize primary CVD prevention. Wider detection of subclinical atherosclerosis, together with structured assessment and effective mitigation of bleeding risk, may appropriately target patients likely to gain net benefit from low dose aspirin therapy.

Severity of stenosis in symptomatic patients undergoing carotid interventions may influence perioperative neurologic events

OBJECTIVE

Carotid artery plaque burden, indirectly measured by the degree of stenosis, quantifies future embolic risk. In natural history studies, patients with moderate degrees of stenosis have a lower stroke risk than those with severe stenosis. However, patients with symptomatic carotid stenosis who have experienced TIA or stroke are found to have both moderate and severe degrees of stenosis. We sought to examine the association carotid artery stenosis severity with outcomes in symptomatic patients undergoing carotid interventions including carotid endarterectomy (CEA), transfemoral carotid artery stenting (CAS) and transcervical carotid artery revascularization (TCAR).

METHODS

The Society for Vascular Surgery Quality Initiative database was queried for all patients undergoing CAS, CEA and TCAR between 2003 and 2020. Patients were stratified into two groups based on the severity of stenosis - non-severe (0 - 69%) and severe (≥ 70%). Primary endpoints were periprocedural neurologic events (strokes and transient ischemic attacks (TIAs)). Secondary endpoints were periprocedural death, myocardial infarction (MI) and composite outcomes of stroke/death and stroke/death/MI per reporting standards for carotid interventions.

RESULTS

Of 29,614 symptomatic patients included in the analysis, 5,296 (17.9%) patients underwent TCAR, 7,844 (26.5%) underwent CAS, and 16,474 (55.6%) underwent CEA for symptomatic carotid artery stenosis. In the CEA cohort, the neurologic event rate was similarly significantly lower in patients with severe stenosis when compared to those with non-severe stenosis (2.6% vs. 3.2%, P=.024). In the TCAR cohort, the periprocedural neurologic even rate was lower in patients with severe stenosis when compared to those with non-severe stenosis (3% vs. 4.3%, P=.033). There was no similar difference noted in the CAS cohort, with periprocedural neurologic event rates of 3.8% in the severe group versus 3.5% in the non-severe group (P=.518). On multivariable analysis, severe stenosis was associated with significantly decreased odds of post procedural neurologic events in patients undergoing CEA (odds ratio [OR] 0.75, 95% confidence interval [CI], 0.6 - 0.92; P=.007) and TCAR (OR .83; CI, .69 - 0.99; P=.039), but not CAS.

CONCLUSION

Severe carotid stenosis as opposed to more moderate degrees of stenosis was associated with decreased rates of periprocedural stroke and TIAs in symptomatic patients undergoing TCAR and CEA, but not CAS. The finding of increased rates of periprocedural neurologic events in symptomatic patients with lesser degrees of stenosis undergoing TCAR and CEA warrants further evaluation with a particular focus on plaque morphology and brain physiology, and their inherent risks with carotid revascularization procedures.

Relationship between subclasses low-density lipoprotein and carotid plaque

Backgound

Low-density lipoprotein (LDL) cholesterol can lead to the occurrence of atherosclerotic plaques, but patients with normal LDL still have atherosclerotic plaques in clinical practice. With the proposal of LDL subclass, this experiment investigated the relationship between the LDL content of different subclasses and the stability of carotid plaques.

Methods

Plaque stability was suggested by carotid ultrasound results. 37 patients with stable plaques were classified into one group and 41 patients with unstable plaques were classified into another group. The data of age, glycosylated hemoglobin (Ghb), and homocysteine (Hcy) were collected. The contents of LDL subclasses were measured by LIPOPRINT system. The data of total cholesterol (TC), LDL cholesterol, and triglyceride (TG) were collected. The plaque stability was assessed by carotid artery color Doppler ultrasound and the intima-media thickness (IMT) was measured.

Results

The levels of LDL-1 subclass 19.00 (13.00, 27.50) and LDL-2 subclass (21.62 ± 7.24) in the stable plaque group were higher than those in the unstable plaque group (p < 0.05). The levels of LDL-3 subclass (12.24 ± 4.58), LDL-4 subclass 5.00 (2.00, 9.00), and sd-LDL 0 (0.00, 3.00) in the unstable plaque group were higher than those in the stable plaque group (p < 0.05). LDL-1 subclass (adjusted OR = 0.923 and p < 0.05), and LDL-3 subclass (adjusted OR = 1.176 and p < 0.05) were independent risk factors for plaque stability.

Conclusion

Elevated LDL1 is associated with stable plaques whereas LDL3 was found associated with unstable plaques.

Non-stenotic Carotid Plaques in Embolic Stroke of Unknown Source

Embolic stroke of unknown source (ESUS) represents one in five ischemic strokes. Ipsilateral non-stenotic carotid plaques are identified in 40% of all ESUS. In this narrative review, we summarize the evidence supporting the potential causal relationship between ESUS and non-stenotic carotid plaques; discuss the remaining challenges in establishing the causal link between non-stenotic plaques and ESUS and describe biomarkers of potential interest for future research. In support of the causal relationship between ESUS and non-stenotic carotid plaques, studies have shown that plaques with high-risk features are five times more prevalent in the ipsilateral vs. the contralateral carotid and there is a lower incidence of atrial fibrillation during follow-up in patients with ipsilateral non-stenotic carotid plaques. However, non-stenotic carotid plaques with or without high-risk features often coexist with other potential etiologies of stroke, notably atrial fibrillation (8.5%), intracranial atherosclerosis (8.4%), patent foramen ovale (5-9%), and atrial cardiopathy (2.4%). Such puzzling clinical associations make it challenging to confirm the causal link between non-stenotic plaques and ESUS. There are several ongoing studies exploring whether select protein and RNA biomarkers of plaque progression or vulnerability could facilitate the reclassification of some ESUS as large vessel strokes or help to optimize secondary prevention strategies.