Value of carotid intima-media thickness and significant carotid stenosis as markers of stroke recurrence

An interpretable machine learning model for stroke recurrence in patients with symptomatic intracranial atherosclerotic arterial stenosis

Background and objective

Symptomatic intracranial atherosclerotic stenosis (SICAS) is the most common etiology of ischemic stroke and one of the main causes of high stroke recurrence. The recurrence of stroke is closely related to the prognosis of ischemic stroke. This study aims to develop a machine learning model based on high-resolution vessel wall imaging (HR-VWI) to predict the risk of stroke recurrence in SICAS.

Methods

This study retrospectively collected data from 180 SICAS stroke patients treated at the hospital between 2020.01 and 2022.01. Relevant imaging and clinical data were collected, and follow-up was conducted. The dataset was divided into a training set and a validation set in a ratio of 7:3. We employed the least absolute shrinkage and selection operator (LASSO) regression to perform a selection on the baseline data, laboratory tests, and neuroimaging data generated by HR-VWI scans collected from the training set. Finally, five machine learning techniques, including logistic regression model (LR), support vector machine (SVM), Gaussian naive Bayes (GNB), Complement naive Bayes (CNB), and k-nearest neighbors algorithm (kNN), were employed to develop a predictive model for stroke recurrence. Shapley Additive Explanation (SHAP) was used to provide visualization and interpretation for each patient. The model's effectiveness was evaluated using average accuracy, sensitivity, specificity, precision, f1 score, PR curve, calibration curve, and decision curve analysis.

Results

LASSO analysis revealed that "history of hypertension," "homocysteine level," "NWI value," "stenosis rate," "intracranial hemorrhage," "positive remodeling," and "enhancement grade" were independent risk factors for stroke recurrence in SICAS patients. In 10-fold cross-validation, the area under the curve (AUC) ranged from 0.813 to 0.912 in ROC curve analysis. The area under the precision-recall curve (AUPRC) ranged from 0.655 to 0.833, with the Gaussian Naive Bayes (GNB) model exhibiting the best ability to predict stroke recurrence in SICAS. SHAP analysis provided interpretability for the machine learning model and revealed essential factors related to the risk of stroke recurrence in SICAS.

Conclusion

A precise machine learning-based prediction model for stroke recurrence in SICAS has been established to assist clinical practitioners in making clinical decisions and implementing personalized treatment measures.

Radiomics Nomogram for Predicting Stroke Recurrence in Symptomatic Intracranial Atherosclerotic Stenosis

Objective

To develop and validate a radiomics nomogram for predicting stroke recurrence in symptomatic intracranial atherosclerotic stenosis (SICAS).

Methods

The data of 156 patients with SICAS were obtained from the hospital database. Those with and without stroke recurrence were identified. The 156 patients were separated into a training cohort (n = 110) and a validation cohort (n = 46). Baseline clinical data were collected from our medical records, and plaque radiological features were extracted from vascular wall high-resolution imaging (VW-HRMRI). The imaging sequences included 3D-T1WI-VISTA, T2WI, and 3D-T1WI-VISTA-enhanced imaging. Least absolute shrinkage and selection operator (LASSO) analysis were used to select the radiomics features associated with stroke recurrence. Then, multiple logistic regression analysis of clinical risk factors, radiological features, and radiomics signatures were performed, and a predictive nomogram was constructed to predict the probability of stroke recurrence in SICAS. The performance of the nomogram was evaluated.

Results

Diabetes mellitus, plaque burden, and enhancement ratio were independent risk factors for stroke recurrence [odds ratio (OR) = 1.24, 95% confidence interval (CI): 1.04–3.79, p = 0.018; OR = 1.76, per 10% increase, 95% CI, 1.28–2.41, p < 0.001; and OR = 1.94, 95% CI: 1.27–3.09, p < 0.001]. Five features of 3D-T1WI-VISTA, six features of T2WI, and nine features of 3D-T1WI-VISTA-enhanced images were associated with stroke recurrence. The radiomics signature in 3D-T1WI-VISTA-enhanced images was superior to the radiomics signature of the other two sequences for predicting stroke recurrence in both the training cohort [area under the curve (AUC), 0.790, 95% CI: 0.669–0.894] and the validation cohort (AUC, 0.779, 95% CI: 0.620–0.853). The combination of clinical risk factors, radiological features, and radiomics signature had the best predictive value (AUC, 0.899, 95% CI: 0.844–0.936 in the training cohort; AUC, 0.803, 95% CI: 0.761–0.897 in the validation cohort). The C-index of the nomogram was 0.880 (95% CI: 0.805–0.934) and 0.817 (95% CI: 0.795–0.948), respectively, in the training and validation cohorts. The decision curve analysis further confirmed that the radiomics nomogram had good clinical applicability with a net benefit of 0.458.

Conclusion

The radiomics features were helpful to predict stroke recurrence in patients with SICAS. The nomogram constructed by combining clinical high-risk factors, plaque radiological features, and radiomics features is a reliable tool for the individualized risk assessment of predicting the recurrence of SICAS stroke.

Ultrasound Assessment of Extracranial Carotids and Vertebral Arteries in Acute Cerebral Ischemia

Assessing ischemic etiology and mechanism during the acute phase of an ischemic stroke is crucial in order to tailor and monitor appropriate treatment and determine prognosis. Cervical Duplex Ultrasound (CDU) has evolved since many years as an excellent screening tool for the evaluation of extracranial vasculature. CDU has the advantages of a low cost, easily applicable, bed side examination with high temporal and spatial resolution and without exposing the patients to any significant complications. It represents an easily repeatable test that can be performed in the emergency room as a first-line examination of cervical artery pathology. CDU provides well validated estimates of the type of the atherosclerotic plaque, the degree of stenosis, as well as structural and hemodynamic information directly about extracranial vessels (e.g., subclavian steal syndrome) and indirectly about intracranial circulation. CDU may also aid the diagnosis of non-atherosclerotic lesions of vessel walls including dissections, arteritis, carotid-jugular fistulas and fibromuscular dysplasias. The present narrative review outlines all potential applications of CDU in acute stroke management and also highlights its potential therapeutic implications.

Carotid Atherosclerosis Evolution When Targeting a Low-Density Lipoprotein Cholesterol Concentration <70 mg/dL After an Ischemic Stroke of Atherosclerotic Origin

BACKGROUND

The TST trial (Treat Stroke to Target) showed the benefit of targeting a low-density lipoprotein cholesterol (LDL-C) concentration of <70 mg/dL in terms of reducing the risk of major cardiovascular events in 2860 patients with ischemic stroke with atherosclerotic stenosis of cerebral vasculature. The impact on carotid atherosclerosis evolution is not known.

METHODS

TST-PLUS (Treat Stroke to Target-Plaque Ultrasound Study) included 201 patients assigned to an LDL-C concentration of <70 mg/dL and 212 patients assigned to a target of 100±10 mg/dL. To achieve these goals, investigators used the statin and dosage of their choice and added ezetimibe as needed. Ultrasonographers were certified and carotid ultrasound examinations were performed using M'Ath software at baseline and at 2, 3, and 5 years. All images were uploaded to the Intelligence in Medical Technologies database directly from the carotid ultrasound device. The central core laboratory performed all offline measurements of the intima-media thickness of both common carotid arteries blinded from the randomization arm. The main outcomes were newly diagnosed atherosclerotic plaque on carotid bifurcation or internal carotid artery using the Mannheim consensus definition and between-group comparison of common carotid arteries intima-media thickness change.

RESULTS

After a median follow-up of 3.1 years, the achieved LDL-C concentrations were 64 mg/dL (1.64 mmol/L) in the lower-target group and 106 mg/dL (2.72 mmol/L) in the higher-target group. Compared with the higher-target group, patients in the lower-target group had a similar incidence of newly diagnosed carotid plaque: 46/201 (5-year rate, 26.1%) versus 45/212 (5-year rate, 29.7%). The change in common carotid arteries intima-media thickness was -2.69 µm (95% CI, -6.55 to 1.18) in the higher-target group and -10.53 µm (95% CI, -14.21 to -6.85) in the lower-target group, resulting in an absolute between-group difference of -7.84 µm (95% CI, -13.18 to -2.51; P=0.004).

CONCLUSIONS

In patients with ischemic stroke and atherosclerosis, an LDL-C target of <70 mg/dL (1.8 mmol/L) did not reduce the incidence of new carotid plaques but produced significantly greater regression of carotid atherosclerosis than an LDL-C target of 90 to 110 mg/dL. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01252875.

Relationship Between Asymptomatic Intracranial Stenosis and Extracranial Arteriosclerotic Findings in Workplace Health Checkups: A Pilot Study

BACKGROUND

Intracranial arteriosclerotic disease (ICAD) is common in Asians and has been presumed to be largely associated with metabolic syndrome (MetS), but the risks for asymptomatic ICAD detectable in examinations of the brain, among other tests, are not well known. The present study is aimed at identifying the risks for asymptomatic ICAD using data on risk factors obtained in health checkups, including data from magnetic resonance imaging (MRI), chest computed tomography (CT), and neck echography.

METHODS

Subjects comprised 103 examinees more than equal to 40 years old (56.9 ± 4.7 years, 93 men) who underwent head MRI, chest CT, and carotid echography in the same period in a workplace health checkup between April and September 2014. Subjects were evaluated for ICAD based on stenosis of bilateral middle cerebral arteries and the basilar artery on previously reported scores from magnetic resonance angiography. Evaluations for extracranial arteriosclerotic disease (ECAD) were based on findings from carotid echography, and total calcium scores were calculated based on the number, areas, and peak Hounsfield computed tomographic numbers of the aortic arch calcified lesion detected.

RESULTS

ICAD, including mild cases with stenosis less than 50%, was seen in 21 subjects (20.3%); and MetS was evident in 12 subjects (11.7%). Logistic regression analysis with multivariate adjustment for major vascular risk factor demonstrated that echogenic of plaque was significantly associated with the ICAD (OR 3.69, 95%CI 1.02-13.3), however age was significant predictor of the risk profile in patients with ECAD.

CONCLUSIONS

Carotid atherosclerosis could predict intracranial atherosclerosis in middle-aged people. However, further study with large sample size is warranted.

Impact of Intima-Media Thickness Progression in the Common Carotid Arteries on the Risk of Incident Cardiovascular Disease in the Suita Study

Background

No prospective study of the relationship between intima–media thickness (IMT) progression and incident cardiovascular disease (CVD) has been performed.

Methods and Results

We studied 4724 participants (mean age: 59.7±11.9 years; without CVD at the baseline) who had carotid ultrasonographic measurement of IMT on both sides of the entire carotid artery area (ie, the entire scanned common carotid artery [CCA], carotid artery bulb, internal carotid artery, and external carotid artery areas for both sides) between April 1994 and August 2001. Carotid ultrasonographic follow‐up was performed every 2 years between April 1994 and March 2005 in 2722 of these participants, newly revealing 193 CCA plaques (maximum IMT in the CCA >1.1 mm). We followed up for incident CVD until December 2013. Statistical analyses were performed using a Cox proportional hazards regression model, evaluated using C statistics, and net reclassification improvement. During the 59 909 person‐years of follow‐up, we observed 221 strokes and 154 coronary heart disease events. CCA plaque and maximum IMT in the whole carotid artery area >1.7 mm were risk factors for CVD. CCA plaque presented an increased risk of CVD based on C statistics and the reclassification improvement of the current risk prediction model. After adding the new incident CCA plaques, during the 23 702 person‐years of follow‐up, 69 strokes and 43 coronary heart disease events occurred. The adjusted hazard ratios for incident CCA plaque were 1.95 (95% confidence interval, 1.14–3.30) in CVD and 2.01 (95% confidence interval, 1.01–3.99) in stroke.

Conclusions

Maximum IMT in the CCA contributed significantly but modestly to the predictive power of incident CVD used in calculating traditional risk factors. This study provides the first demonstration that new progression of incident CCA plaque is a CVD risk.

Association of body flexibility and carotid atherosclerosis in Japanese middle-aged men: a cross-sectional study

OBJECTIVE

This study examined the associations of body flexibility with carotid arterial remodelling, including intima-media thickness (IMT) and plaque formation in middle-aged men.

METHODS

The subjects of this cross-sectional study included 1354 Japanese men aged 35-59 years without histories of stroke or cardiac diseases. The arm extensibility test, which can estimate flexibility of the upper extremity (composed of shoulder external rotation and forearm supination), and the sit-and-reach test were performed. Common carotid IMT and plaque formation (≥1.1 mm) were estimated by ultrasound.

RESULTS

The proportion of subjects who fully completed the arm extensibility test was 55.0%, and who had plaques in the common carotid artery was 37.8%. IMT was associated with poor arm extensibility (β=-0.073, 95% CI -0.02224 to -0.00041, P=0.004), while plaque formation was associated with poor sit-and-reach (OR 0.98579, 95% CI 0.97257 to 0.99919, P=0.038) after adjustment by all covariates.

CONCLUSIONS

This study demonstrated that poor upper extremity and trunk flexibility were associated with characteristics of early onset of atherosclerosis. Furthermore, these associations were independent of covariates such as age, blood pressure, blood lipids glucose levels and abdominal fat accumulation, handgrip strength and lifestyle, including sleeping, drinking, exercise and smoking habits. Poor flexibility may reflect subclinical atherosclerosis in middle-aged men.

Carotid Intima-Media Thickness Is Associated With White Matter Hyperintensities: The Northern Manhattan Study

BACKGROUND AND PURPOSE

Brain white matter hyperintensities (WMH) have been associated with increased risk of stroke, cognitive decline, and dementia. WMH can be a manifestation of small vessel disease, although the total microvascular contribution to multifactorial WMH pathophysiology remains unknown. We hypothesized a possible relationship between carotid intima-media thickness (cIMT), an ultrasound imaging marker of subclinical vascular disease, and brain WMH in a multiethnic, elderly stroke-free community-based cohort.

METHODS

We evaluated the relationship between cIMT and WMH in the population-based Northern Manhattan Study, among individuals free of stroke. We used linear regression to examine the association of continuous measures of cIMT with quantitatively derived WMH volume, as a proportion of cranial volume, measured from fluid-attenuaded inversion recovery magnetic resonance imaging while adjusting for sociodemographics, lifestyle, and vascular risk factors.

RESULTS

In a cohort of 1229 participants (mean age, 71±9 years; 60% women, 15% White; 18% Black; 65% Hispanics), the mean cIMT was 0.71±0.08 mm and the median log-transformed WMH volume was 0.36 (interquartile range, 0.21-0.76). In a multivariable model, larger cIMT was significantly associated with greater WMH volume (β=0.046 per SD cIMT; P=0.04). Age and race/ethnicity were significant modifiers (P for age, 0.02; and P for race/ethnicity, 0.04). cIMT was associated with WMH volume in participants 70 years or older (β=0.088 per SD cIMT; P=0.01) and among Hispanics (β=0.084 per SD cIMT; P=0.003).

CONCLUSIONS

Larger cIMT was associated with greater burden of cerebral WM lesions independently of demographics and traditional vascular risk factors, particularly among elderly and Hispanic participants, who are at high risk for stroke and cognitive decline.

Morphometric measurements of extracranial and intracranial atherosclerotic disease: A population-based autopsy study

BACKGROUND AND AIMS

Intracranial (IAD) and extracranial atherosclerotic diseases (EAD) have been mostly investigated using imaging methods. Autopsy studies allow for a direct and complete evaluation of the atherosclerotic disease. We aimed to investigate the frequency of IAD and EAD, their association, and related risk profiles in a large cross-sectional autopsy study.

METHODS

We measured the intima-media thickness and stenosis of the common (CCA) and internal carotid arteries (ICA), using morphometric measurements. The main outcome was stenosis (≥50%) in the artery with the largest obstruction among the 12 cerebral arteries. We used multivariable logistic regression models to investigate the association between EAD and IAD.

RESULTS

In 661 participants (mean age = 71.3 ± 11.7 y, 51% male), stenosis was more common in IAD than in EAD (59% vs. 51%). EAD was associated with Caucasian race, hypertension, and smoking, while IAD was associated with older age, less years of education, hypertension, diabetes, and a previous history of stroke. Stenosis in CCA and ICA was associated with more than two times the odds of having stenosis in the intracranial arteries (CCA: OR = 2.32, 95% CI = 1.64; 3.28; ICA: OR = 2.51, 95% CI = 1.76; 3.57).

CONCLUSIONS

In this population-based autopsy study, IAD was common, even more common than EAD, but correlated with EAD.

Carotid plaque rather than intima-media thickness as a predictor of recurrent vascular events in patients with acute ischemic stroke

Background

To investigate the impacts of carotid plaque and intima-media thickness (IMT) on future vascular events (VEs) in the patients with acute ischemic stroke.

Methods

A total of 479 consecutive Korean patients with acute ischemic stroke were divided into 2 groups according to development of VEs; VE group (65.4 ± 10.9 years) vs no VE group (62.8 ± 13.2 years). VEs were defined as the development of recurrent stroke, coronary events, peripheral arterial disease, and death. Clinical, laboratory, and imaging findings were compared between the groups.

Results

During 105.5 ± 29.0 months of follow up, VEs were developed in 142 patients (29.6%). In univariate analysis, VEs were significantly associated with age, gender, diabetes, renal function, lipid levels, left ventricular function, carotid plaque or IMT. In multivariate analysis, the presence of carotid plaque, diabetes, renal function and male gender were independent predictors of future VEs in the patients with ischemic stroke, but carotid IMT was not a predictor of future VEs. Event free survival was significantly lower in patients with carotid plaque than without carotid plaque on Kaplan-Meier analysis (log rank p < 0.001).

Conclusion

The present study demonstrated that diabetes, impaired renal function, male gender, and the presence of carotid plaque rather than IMT were independent predictors of future VEs in Korean patients with acute ischemic stroke. Active medical management and careful monitoring for the development of recurrent VEs are strongly recommended in patients with acute ischemic stroke and carotid plaque.

The Japan Statin Treatment Against Recurrent Stroke (J-STARS) Echo Study: Rationale and Trial Protocol

OBJECTIVE

The preventive effect of 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins) on progression of carotid intima-media complex thickness (IMT) has been shown exclusively in nonstroke Western patients. The Japan Statin Treatment Against Recurrent Stroke (J-STARS) Echo Study aims to determine the effect of pravastatin on carotid IMT in Japanese patients with hyperlipidemia who developed noncardioembolic ischemic stroke.

DESIGN

This is a substudy of the J-STARS, a multicenter, randomized, open-label, blinded-end point, parallel-group trial to examine whether pravastatin reduces stroke recurrence in patients with noncardioembolic stroke. The patients are randomized to receive pravastatin (10 mg daily) or not to receive any statins. Carotid ultrasonography is performed by well-trained certified examiners in each participating institute, and the recorded data are measured centrally. The primary outcome is change in the IMT of the distal wall in a consecutive 2-cm section on the central side of the common carotid artery bifurcation over 5 years of observation.

CONCLUSION

The trial may help determine if the usual dose of pravastatin for daily clinical practice in Japan can affect carotid IMT in Japanese patients with noncardioembolic stroke.

Carotid Intima-Media Thickness is Not Associated with Markers of Atherosclerosis in Stroke Patients

BACKGROUND

It has been argued that carotid intima-media thickness (IMT) could better reflect an adaptive response of the vessel wall rather than being a marker of atherosclerosis. We explore this hypothesis by analyzing the ARTICO data.

METHODS

The ARTICO study was designed to evaluate the prognostic value of the pathological ankle-brachial index (ABI) for the emergence of new vascular events in patients who have suffered a noncardioembolic stroke. Collected variables were as follows: vascular risk factors, mean waist perimeter, quantification of carotid IMT, characteristics of carotid plaques, ABI, and presence of microalbuminuria.

RESULTS

A total of 591 patients with a complete carotid evaluation were available. There was no correlation between ABI and IMT (Spearman's, p NS). Logistic regression revealed that pathological ABI correlated significantly only with internal carotid artery stenosis greater than or equal to 50% (OR [odds ratio] 2.80, 1.66-4.71, P < .01) and peripheral artery disease (OR 3.33, 1.63-6.78, P < .01). However, multivariate regression analysis demonstrated that carotid IMT was independently associated with age (OR 1.05, 95% confidence interval [CI] 1.02-1.09, P < .01), hypertension (OR 1.83, 95% CI 1.02-3.26, P = .04), waist circumference (OR 1.03, 95% CI 1.01-1.05, P < .01), and microalbuminuria (OR 2.02, 95% CI 1.22-3.35, P < .01).

CONCLUSION

In our patients, carotid IMT does not seem to be associated with unequivocal markers of atheromatosis such as the existence of relevant carotid plaques or pathological ABI. These results as well as the association of IMT with age, hypertension, microalbuminuria, and mean waist perimeter support the hypothesis that IMT must be considered a risk factor for general vascular disease rather than a marker of atherosclerotic burden.

Prognostic implications of the Ankle Brachial Index in patients with acute ischemic stroke: A meta-analysis

BACKGROUND

The ankle brachial index (ABI) is recognized as a marker of atherosclerotic disease. The detection of ABI may improve the risk stratification.

METHODS

We systematically searched Pubmed and Embase (from the earliest date to October 2015) for studies evaluating the prognostic value of ABI in patients with acute ischemic stroke. Stroke or cardiovascular events, mortality and functional outcomes were analyzed.

RESULTS

Seventeen studies, containing 9404 patients, were included. The mean age of participants in each study ranged from 64 to 79 years. The prevalence of low ABI varied from 7.4% to 40.5%. In this quantitative analysis, we found that low ABI increased the risk of composite outcomes (myocardial infarction or stroke or mortality), disability and mortality.

CONCLUSION

The detection of ABI may help to identify high-risk patients for secondary stroke prevention.

Correlation between Carotid Intima-Media Thickness and Early-Stage Chronic Kidney Disease: Results from Asymptomatic Polyvascular Abnormalities in Community Study

OBJECTIVE

Chronic kidney disease (CKD) might be a potential independent risk factor for increased carotid intima-media thickness (IMT). Our aim is to determine whether mild to moderate kidney dysfunction is associated with increased carotid IMT.

METHODS

We employed 3629 subjects free from clinical cardiovascular diseases at the baseline visit of the Asymptomatic Polyvascular Abnormalities in Community Study. Kidney function was evaluated in terms of estimated glomerular filtration rate (eGFR) calculated by the Chronic Kidney Disease Epidemiology Collaboration China equation. The mean of the maximal internal and common carotid IMT was measured by means of high-resolution B-mode ultrasound. Univariable linear regressions and multivariate logistic regressions were used to evaluate the independent association between kidney function and carotid IMT.

RESULTS

In the unadjusted linear analysis, carotid IMT showed a significant negative correlation with eGFR in both male (r = -.346, P < .001) and female (r = -.253, P < .001) subjects. After adjustment for age, traditional vascular risk factors (smoking, diabetes, systolic blood pressure, diastolic blood pressure, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, total cholesterol, and antihypertensive drug use), and nontraditional risk factors (C-reactive protein and homocysteine), the association remained significant. The odds ratio for increased IMT was 1.299 (95% confidence interval [CI], 1.062-1.588) in the group with an eGFR of 60-89 mL/minute/1.73 m(2) and 1.789 (95% CI, 1.203-2.660) in the group with an eGFR of 30-59 mL/minute/1.73 m(2).

CONCLUSIONS

Increased IMT is associated with early-stage CKD. This association is independent of traditional and nontraditional cardiovascular risk factors. Early detection of kidney dysfunction is important to improve risk stratification of atherosclerotic disease.

Endothelial Progenitor Cells Predict Cardiovascular Events after Atherothrombotic Stroke and Acute Myocardial Infarction. A PROCELL Substudy

Introduction

The aim of this study was to determine prognostic factors for the risk of new vascular events during the first 6 months after acute myocardial infarction (AMI) or atherothrombotic stroke (AS). We were interested in the prognostic role of endothelial progenitor cells (EPC) and circulating endothelial cells (CEC)

Methods

Between February 2009 and July 2012, 100 AMI and 50 AS patients were consecutively studied in three Spanish centres. Patients with previously documented coronary artery disease or ischemic strokes were excluded. Samples were collected within 24h of onset of symptoms. EPC and CEC were studied using flow cytometry and categorized by quartiles. Patients were followed for up to 6 months. NVE was defined as new acute coronary syndrome, transient ischemic attack (TIA), stroke, or any hospitalization or death from cardiovascular causes. The variables included in the analysis included: vascular risk factors, carotid intima-media thickness (IMT), atherosclerotic burden and basal EPC and CEC count. Multivariate survival analysis was performed using Cox regression analysis.

Results

During follow-up, 19 patients (12.66%) had a new vascular event (5 strokes; 3 TIAs; 4 AMI; 6 hospitalizations; 1 death). Vascular events were associated with age (P = 0.039), carotid IMT≥0.9 (P = 0.044), and EPC count (P = 0.041) in the univariate analysis. Multivariate Cox regression analysis showed an independent association with EPC in the lowest quartile (HR: 10.33, 95%CI (1.22–87.34), P = 0.032] and IMT≥0.9 [HR: 4.12, 95%CI (1.21–13.95), P = 0.023].

Conclusions

Basal EPC and IMT≥0.9 can predict future vascular events in patients with AMI and AS, but CEC count does not affect cardiovascular risk.

Cognitive functions of carotid artery stenosis in the aged rat

Carotid artery stenosis appears to be an independent risk factor for cognitive impairment. But the mechanisms of cognitive impairments occurring in patients with asymptomatic carotid stenosis are poorly understood. One important reason is the absence of a good carotid stenosis model. In the present study, after establishing different degrees of carotid stenosis models in aged rats successfully, we investigated their cognitive function. Wistar rat models with carotid artery stenosis were established by ligating the common carotid artery along with various gauges of needle and then removing the needle. The cognitive performance was assessed using Morris water maze (MWM) task. Cholinergic markers like acetylcholine (ACh) were evaluated in hippocampus. Neuronal damage was also studied through morphological changes. Severe carotid stenosis led to impairment in learning ability and memory retrieval, accompanied with a decrease in ACh level and morphological damage in hippocampus. Moderate carotid stenosis rats had a partial cognitive impairment, but there were no changes in ACh level and morphological damage in hippocampus. Meanwhile, mild carotid stenosis rats had no cognitive impairment compared to sham-operated rats. The results of this study suggest that different degrees of carotid stenosis induce different cognitive changes in aged rats.