Validity and Reliability of Point-of-Care Ultrasound for Detecting Moderate- or High-Grade Carotid Atherosclerosis in an Outpatient Department

The prevalence of carotid stenosis is considerably higher in asymptomatic individuals with multiple risk factors than in the general population. We investigated the validity and reliability of carotid point-of-care ultrasound (POCUS) for rapid carotid atherosclerosis screening. We prospectively enrolled asymptomatic individuals with carotid risk scores of ≥7 who underwent outpatient carotid POCUS and laboratory carotid sonography. Their simplified carotid plaque scores (sCPSs) and Handa's carotid plaque scores (hCPSs) were compared. Of 60 patients (median age, 81.9 years), 50% were diagnosed as having moderate- or high-grade carotid atherosclerosis. The overestimation and underestimation of outpatient sCPSs were more likely in patients with low and high laboratory-derived sCPSs, respectively. Bland-Altman plots indicated that the mean differences between the participants' outpatients and laboratory sCPSs were within two standard deviations of their laboratory sCPSs. A Spearman's rank correlation coefficient revealed a strong positive linear correlation between outpatient and laboratory sCPSs (r = 0.956, p < 0.001). An intraclass correlation coefficient analysis indicated excellent reliability between the two methods (0.954). Both carotid risk score and sCPS were positively and linearly correlated with laboratory hCPS. Our findings indicate that POCUS has satisfactory agreement, strong correlation, and excellent reliability with laboratory carotid sonography, making it suitable for rapid screening of carotid atherosclerosis in high-risk patients.

Factors associated with the elasticity of asymptomatic carotid plaques in hypertension Tibetan population

AIMS

Hypertension is a major risk factor for coronary, cerebrovascular, and the greatest cause of stroke. Half of stroke events are the result of cerebrovascular atherosclerosis, including carotid plaques. It is of major importance to detect which plaques are vulnerable, even though not yet ruptured. Due to the particularity of the Tibetan population, this study evaluated the elasticity of asymptomatic carotid plaques in Tibetan hypertension patients using shear wave elastography (SWE) and explored associated risk factors.

METHODS

A total of 91 Tibetan patients were divided into normotension, grade 1-2, and grade 3 hypertension groups based on the level of blood pressure. All subjects underwent common duplex ultrasonic examination and SWE evaluation for carotid plaques. Elasticity of carotid plaque was assessed by Young's modulus.

RESULTS

The final analysis included 126 plaques as representative plaques according to Total Plaque Risk Score. The mean and maximum Young's modulus in the grade 3 hypertension group were smaller, and more plaques with irregularity surface compared with the other two groups (p < 0.05). Multivariate regression analysis showed drinking butter tea (β = -0.220, p = 0.009; β = -0.240, p = 0.004, respectively) was the independent factor associated with mean and maximum Young's modulus.

CONCLUSIONS

SWE is feasible for measurement of Young's modulus of carotid plaques. Plaques in the grade 3 hypertension group were more likely to become vulnerable ones. In hypertension Tibetan patients, drinking butter tea was an independent factor associated with mean and maximum Young's modulus of asymptomatic carotid plaque.

Analysis of atherosclerotic plaque distribution in the carotid artery

BACKGROUND

The present study was designed to investigate the hypothesis that the outer wall at the carotid bifurcation is the most common area of atherosclerotic plaque deposition due to the low shear stress.

HYPOTHESIS

We hypothesized that the most common site of arteriosclerosis in carotid arteries is different in the early and late stages.

METHODS

This is an observational study of patients with <50% stenosis of the common and internal carotid arteries (ICAs) identified by Duplex ultrasound in our health promotion center. Plaque location was categorized as a quarter of the cross-section in the distal common carotid artery (CCA) and proximal ICA. Carotid plaque score (CPS) was calculated by the addition of one point for each detected section. The sum of CPSs was calculated for each section.

RESULTS

Among 3996 Duplex scans of carotid arteries in 999 patients between June 2020 and October 2020, a total of 569 patients (73.6% male; mean age, 68.4± 9.1 years; 652 CCAs and 567 ICAs) were included. Total CPS was high in the anterior and posterior sections. The distribution in the ICA was: 308 (31.0%) anterior, 90 (9.0%) medial, 373 (37.5%) posterior, and 224 (22.5%) lateral section. The distribution in the CCA was 385 (32.6%) anterior, 103 (8.7%) medial, 528 (44.7%) posterior, and 165 (14.0%) lateral section. The axial distribution of posterior and lateral sections was significantly different according to the directional flow (p < .001).

CONCLUSIONS

Anterior and posterior sections of the CCA and ICA were atherosclerotic plaque-prone sites. This result is different from the tendency of atherogenesis to affect the lateral section having low shear stress at the carotid bifurcation.

Nomogram and Carotid Risk Score for Predicting Moderate or High Carotid Atherosclerosis among Asymptomatic Elderly Recycling Volunteers

Carotid atherosclerosis is associated with cardiovascular and cerebrovascular events. We explored an appropriate method for selecting participants without ischemic cerebrovascular disease but with various comorbidities eligible for a carotid ultrasound. This was a retrospective subgroup analysis of the carotid plaque burden from a previous study involving a vascular and cognitive survey of 956 elderly recycling volunteers (778 women and 178 men; mean age: 70.8 years). We used carotid ultrasound to detect the carotid plaque and computed the carotid plaque score (CPS). A moderate or high degree of carotid atherosclerosis (MHCA) was defined as CPS > 5 and was observed in 22% of the participants. The CPS had positive linear correlations with age, systolic blood pressure, and fasting glucose. We stratified the participants into four age groups: 60−69, 70−74, 75−79, and ≥80 years. Multivariable analysis revealed that significant predictors for MHCA were age, male sex, hypertension, diabetes mellitus, hyperlipidemia, coronary artery disease, and a nonvegetarian diet. Coronary artery disease and advanced age were the two strongest predictors. We chose the aforementioned seven significant predictors to establish a nomogram for MHCA prediction. The area under the receiver operating characteristic curve in internal validation with 10-fold cross-validation and the classification accuracy of the nomogram were 0.785 and 0.797, respectively. We presumed people who have a ≥50% probability of MHCA warranted a carotid ultrasound. A flowchart table derived from the nomogram addressing the probabilities of all models of combinations of comorbidities was established to identify participants who had a probability of MHCA ≥ 50% (corresponding to a total nomogram score of ≥15 points). We further established a carotid risk score range from 0 to 17 comprising the seven predictors. A carotid risk score ≥ 7 was the most optimal cutoff value associated with a probability of MHCA ≥ 50%. Both total nomogram score ≥ 15 points and carotid risk score ≥ 7 can help in the rapid identification of individuals without stroke but who have a ≥50% probability of MHCA—these individuals should schedule a carotid ultrasound.

Carotid plaque surface echogenicity predicts cerebrovascular events: An Echographic Multicentric Swiss Study

BACKGROUND AND PURPOSE

To determine the prognostic value for ischemic stroke or transitory ischemic attack (TIA) of plaque surface echogenicity alone or combined to degree of stenosis in a Swiss multicenter cohort METHODS: Patients with ≥60% asymptomatic or ≥50% symptomatic carotid stenosis were included. Grey-scale based colour mapping was obtained of the whole plaque and of its surface defined as the regions between the lumen and respectively 0-0.5, 0-1, 0-1.5, and 0-2 mm of the outer border of the plaque. Red, yellow and green colour represented low, intermediate or high echogenicity. Proportion of red color on surface (PRCS) reflecting low echogenictiy was considered alone or combined to degree of stenosis (Risk index, RI).

RESULTS

We included 205 asymptomatic and 54 symptomatic patients. During follow-up (median/mean 24/27.7 months) 27 patients experienced stroke or TIA. In the asymptomatic group, RI ≥0.25 and PRCS ≥79% predicted stroke or TIA with a hazard ratio (HR) of respectively 8.7 p = 0.0001 and 10.2 p &lt; 0.0001. In the symptomatic group RI ≥0.25 and PRCS ≥81% predicted stroke or TIA occurrence with a HR of respectively 6.1 p = 0.006 and 8.9 p = 0.001. The best surface parameter was located at 0-0.5mm. Among variables including age, sex, degree of stenosis, stenosis progression, RI, PRCS, grey median scale values and clinical baseline status, only PRCS independently prognosticated stroke (p = 0.005).

CONCLUSION

In this pilot study including patients with at least moderate degree of carotid stenosis, PRCS (0-0.5mm) alone or combined to degree of stenosis strongly predicted occurrence of subsequent cerebrovascular events.

Clinical Significance of Carotid Intima-Media Complex and Carotid Plaque Assessment by Ultrasound for the Prediction of Adverse Cardiovascular Events in Primary and Secondary Care Patients

Recently published recommendations from the American Society of Echocardiography on 'Carotid Arterial Plaque Assessment by Ultrasound for the Characterization of Atherosclerosis and Evaluation of Cardiovascular Risk' provoked discussion once more on the potential clinical applications of carotid intima-media complex thickness (CIMT) and carotid plaque assessment in the context of cardiovascular risk in both primary and secondary care patients. This review paper addresses key issues and milestones regarding indications, assessment, technical aspects, recommendations, and interpretations of CIMT and carotid plaque findings. We discuss lacks of evidence, limitations, and possible future directions.

The Course of Carotid Plaque Vulnerability Assessed by Advanced Neurosonology

Background: Carotid artery atherosclerosis is a major risk factor for ischemic stroke. This risk is related to plaque vulnerability and is characterized by plaque morphology, intraplaque neovascularization, and cerebral microembolization. Advanced neurosonology can identify vulnerable plaques and aid in preventing subsequent stroke. We aimed to assess the time course of cerebral microembolization and intraplaque neovascularization during 6 months of follow-up and to explore the utility of advanced neurosonology in patients with acute cerebral ischemia.

Methods: Fifteen patients with acute cerebral ischemia and carotid artery plaques underwent comprehensive extra- and intracranial ultrasound examinations, including microemboli detection and contrast-enhanced ultrasound. The examinations were repeated after 3 and 6 months.

Results: We examined 28 plaques in 15 patients. The ultrasonographic features of plaque vulnerability were frequent in symptomatic and asymptomatic plaques. There were no significant differences in stenosis degree, plaque composition, plaque surface, neovascularization, or cerebral microembolization between symptomatic and asymptomatic plaques, but symptomatic plaques had a higher number of vulnerable features. None of the patients had recurrent clinical stroke or transient ischemic attack during the follow-up period. We observed a decrease in cerebral microembolization at 6 months, but no significant change in intraplaque neovascularization.

Conclusions: In patients with acute cerebral ischemia and carotid artery plaques, cerebral microembolization decreased during 6 months of follow-up, indicating plaque stabilization.

Clinical Trial Registration:ClinicalTrial.gov, identifier NCT02759653.

The Predictive Value of Carotid Ultrasonography With Cardiovascular Risk Factors-A "SPIDER" Promoting Atherosclerosis

Insufficient recommendations do not support the clinical use of carotid ultrasonography for further risk stratification in moderate-to-high risk patients with cardiovascular disease (CVD). A literature review was performed to assess six aspects of the research progress and limitations of carotid ultrasonography and carotid atherosclerosis-related risk factors: (1) structures of the carotid intima and media; (2) plaques; (3) inflammation; (4) dynamics of carotid blood flow; (5) early detection and intervention; and (6) risk factors for CVD. Although carotid intima-media thickness and carotid plaques are well-acknowledged independent predictors of CVD risk, normative and cut-off values are difficult to define due to the heterogeneous measurements reported in previous studies. Plaque properties, including location, number, density, and size, become more important risk predictors for cardiovascular disease, but a better approach for clinical use needs to be further established. Three-dimensional ultrasound and contrast-enhanced ultrasound are promising for promoting risk stratification with more details on plaque morphology. Moreover, inflammatory diseases and biomarkers should be evaluated for a full assessment of the inflammatory burden for atherosclerosis. Carotid flow velocity is not only an indicator for stenosis but also a potential risk predictor. Carotid atherosclerosis should be detected and treated early, and additional clinical trials are needed to determine the efficacy of these measures in reducing CVD risk. Cardiovascular risk factors tend to affect carotid plaques, and early treat-to-target therapy might yield clinical benefits. Based on the aforementioned six aspects, we consider that these six important factors act like a “SPIDER” spinning the web of atherosclerosis; a timely comprehensive assessment and intervention may halt the progression to CVD. Carotid ultrasound results should be combined with other atherosclerotic factors, and a comprehensive risk assessment may help to guide cardiovascular prevention decisions.

A systematic review of the status and methodological considerations for estimating risk of first ever stroke in the general population

AIMS

The methodological quality of development, validation, and modification of those models have not been evaluated via a thoroughly literature review. This study aims to describe the overall status and evaluate the methodological quality of risk prediction models for stroke incidence in the general population.

METHODS

We searched the database of EMBASE and MEDLINE by the combination of subject words and key words to collect the research on stroke risk prediction model in the general population. The retrieval time was from the establishment of the database to September 2019. It should be mentioned that risk of bias for each model was assessed, and data on population characteristics and model performance was also extracted.

RESULTS

The search screened 11,386 peer-reviewed publications and 57 citation searching, of which 48 were included in the review, describing the development of 51 prediction models, 47 external validation models, and 12 modification models. Among 51 development models, the predicted outcome concentrated on fatal or non-fatal stroke (n = 37, 73%). Thirty-nine development models (76%) were without internal validation. C-statistic or AUC was adopted for discrimination in 80% models, and Hosmer-Lemeshow test (n = 25, 49%) was also performed for calibration. Twenty-six development models (53%) were externally validated, among which only 2 (8%) were validated by independent researchers. Risk prediction performance was improved when models were modified by adding novel risk factors, such as the internal carotid artery plaque and intima-media thickness.

CONCLUSION

Models for predicting stroke occurrence need further external validation, recalibration, or modification in different populations, to help interpret those models in the practice of stroke prevention.

Relative Estimate of Revised Cardiovascular Risk Combining Traditional and Non-traditional Image-based CV Markers: A Kerala Based Study

BACKGROUND

Non-traditional image markers can improve the traditional cardiovascular risk estimation, is untested in Kerala based participants.

OBJECTIVE

To identify the relationship between the 'Modified CV risk' categories with traditional and non-traditional image-based risk markers. The correlation and improvement in reclassification, achieved by pooling atherosclerotic non-traditional markers with Intermediate (≥7.5% and <20%) and High (≥20%) 10-year participants is evaluated.

METHODS

The cross-sectional study with 594 participants has the ultrasound measurements recorded from the medical archives of clinical locations at Ernakulum district, Kerala. With carotid Intima-Media Thickness (cIMT) measurement, the Plaque (cP) complexity was computed using selected plaque characteristics to compute the carotid Total Plaque Risk Score (cTPRS) for superior risk tagging. Statistical analysis was done using RStudio, the classification accuracy was verified using the decision tree algorithm.

RESULTS

The mean age of the participants was (58.14±10.05) years. The mean cIMT was (0.956±0.302) mm, with 65.6% plaque incidence. With 94.90% variability around its mean, the Multinomial Logistic Regression model identifies cIMT and cTPRS, age, diabetics, Familial Hypercholesterolemia (FH), Hypertension treatment, the presence of Rheumatoid Arthritis (RA), Chronic Kidney Disease (CKD) as significant (p<0.05). cIMT and cP were found significant for 'Intermediate High', 'High' and 'Very High' 'Modified CV risk' categories. However, age, diabetes, gender and use of hypertension treatment are significant for the 'Intermediate' 'Modified CV risk' category. The overall performance of the MLR model was 80.5%. The classification accuracy verified using the decision tree algorithm has 78.7% accuracy.

CONCLUSION

The use of atherosclerotic markers shows a significant correlation suitable for a nextlevel reclassification of the traditional CV risk.

Antithrombotic treatment of asymptomatic carotid atherosclerosis: a medical dilemma

Carotid artery atherosclerosis (CAAS) is a common finding in asymptomatic subjects evaluated for cardiovascular (CV)-risk stratification. Besides the careful control of CV-risk factors, antithrombotic agents, and in particular aspirin, may be considered for primary prevention in patients at CV-risk. However, there is strong controversy on the use of aspirin in primary prevention. Even if several studies confirmed the association between CAAS and CV-events, CAAS is not universally recognized as an independent risk factor and the choice to use aspirin as primary prevention in these patients remains a medical dilemma. Here we review the available evidence on the prognostic value of asymptomatic CAAS for major CV-events and on the utility of antithrombotic agents in this population. We conclude that the detection of asymptomatic CAAS can not be considered as a direct indication to carry out primary prophylaxis with antithrombotic drugs, and the choice to use aspirin should be made only after the careful estimate of the individual's CV-and hemorrhagic risk.

Micro-structural white matter abnormalities and cognitive impairment in asymptomatic carotid plaque patients: A DTI study using TBSS analysis

BACKGROUND

It has been shown that symptomatic or severe carotid atherosclerosis is closely related to cognitive impairment and brain white matter damage. However, there is still a lack of effective and non-invasive imaging biomarkers to identify early high-risk cerebrovascular diseases. Therefore, the purpose of this study is to explore the integrity of brain white matter and cognitive impairment in patients with asymptomatic carotid plaques by using imaging technology.

METHODS

All subjects were from a project of Stroke Risk Screening and Prevention and were defined as stroke high-risk patients (with three or more stroke risk factors). Tract-based spatial statistics (TBSS) based on diffusion tensor imaging (DTI) was used to analyze the whole brain white matter abnormalities in 61 patients with carotid artery plaque and in 40 healthy controls. At the same time, the general clinical data between the two groups were compared, such as age, gender, smoking, hypertension and cognitive function scores etc. Furthermore, the plaque group was divided into the have-hyperintensities group and the no-hyperintensities group to compare their microstructure of white matter injuries.

RESULTS

The cognitive scores of plaque group were significantly lower than that of control group. We found that when plaque group and control group were compared, no white matter fiber tracts with difference was found in FA, MD, AD and RD. However, the decrease of FA and the increase of RD were found in some white matter regions (P < 0.05) when comparing the have-hyperintensities group and the no-hyperintensities group. These white matter regions included anterior thalamic radiation, corticospinal tract, cingulum (cingulate gyrus), forceps minor, inferior fronto-occipital fasciculus, superior longitudinal fasciculus, uncinate fasciculus. What's more, there were significant differences in blood pressure between the two groups.

CONCLUSION

The cognitive function of patients with early high-risk cerebrovascular diseases (asymptomatic carotid plaques) has a downward trend. TBSS based on DTI can help to find out the actual damage of brain white matter in patients with early carotid plaque, and reflect the early pathological changes from the micro level.

Three-dimensional ultrasonographic evaluation of carotid artery plaque surface irregularity

INTRODUCTION

The aim of this study was to evaluate 3-dimensional (3D) ultrasonography (US) in determining the surface irregularity of carotid artery plaques.

MATERIAL AND METHODS

This study included 50 patients (20 females and 30 males) aged between 56 and 82 years with plaques in the carotid artery which were detected during routine neck ultrasound. Simultaneously these cases were evaluated in terms of plaque echogenicities and surface characteristics with 2D and 3D US.

RESULTS

3D imaging was successfully performed in 45 of the 50 cases and the technical success rate was 90%. A single plaque was detected in 64.4% of the patients, with the remaining 35.6% having more than one plaque. The lengths of the plaques ranged from 2 to 12 mm (mean: 3.98 ±1.70 mm); the widths ranged from 1.8 to 3.2 mm (mean: 2.11 ±0.37 mm). No significant difference was found between 2D and 3D plaque echo-structures (observer 1, p = 0.317; observer 2, p = 0.276), but there were significant differences between 2D and 3D plaque surface irregularities (observer 1, p = 0.002; observer 2, p = 0.004). The inter-observer agreement on 2D and 3D plaque echo-structure and surface irregularity was very good (k coefficients were 0.89 and 0.83, respectively, for echo-structure, and 0.91 and 0.95, respectively, for surface irregularity).

CONCLUSIONS

The present study shows that 3D US examination is a valuable non-invasive method for investigation of surface irregularity of carotid artery plaques.

An Ultrasonographic Multiparametric Carotid Plaque Risk Index Associated with Cerebrovascular Symptomatology: A Study Comparing Color Doppler Imaging and Contrast-Enhanced Ultrasonography

BACKGROUND AND PURPOSE

Various ultrasonographic features of carortid plaques have been associated with the occurence of stroke, highlighting the need for multi-parametric assessment of plaque's vulnerability. Our aim was to compare ultrasonographic multiparametric indices using color Doppler imaging and contrast-enhanced sonography between symptomatic and asymptomatic carotid plaques.

MATERIALS AND METHODS

This was a cross-sectional observational study recruiting 54 patients (72.2% male; median age, 61 years) undergoing sonography and contrast-enhanced sonography. Patients were included if a moderately or severely stenotic internal carotid artery plaque was detected, with the plaque being considered symptomatic if it was ipsilateral to a stroke occuring within the last 6 months. A vulnerability index, previously described by Kanber et al, combined the degree of stenosis, gray-scale median, and a quantitative measure of surface irregularities (surface irregularity index) derived from color Doppler imaging and contrast-enhanced ultrasonography, resulting in 2 vulnerability indices, depending on the surface irregularity index used. Mann-Whitney U and t tests were used to compare variables between groups, and receiver operating characteristic curves were used to compare diagnostic accuracy.

RESULTS

Sixty-two plaques were analyzed (50% symptomatic), with a mean degree of stenosis of 68.9%. Symptomatic plaques had a significantly higher degree of stenosis (mean, 74.7% versus 63.1%; P < .001), a lower gray-scale median (13 versus 38; P = .001), and a higher Kanber vulnerability index based both on color Doppler imaging (median, 61.4 versus 16.5; P < .001) and contrast-enhanced ultrasonography (median, 88.6 versus 25.2; P < .001). The area under the curve for the detection of symptomatic plaques was 0.772 for the degree of stenosis alone, 0.783 for the vulnerability index-color Doppler imaging, and 0.802 for the vulnerability index-contrast-enhanced ultrasonography, though no statistical significance was achieved.

CONCLUSIONS

Symptomatic plaques had a higher degree of stenosis, lower gray-scale median values, and higher values of the Kanber vulnerability index using both color Doppler imaging and contrast-enhanced ultrasonography for plaque surface delineation.

Interoperator Reproducibility of Carotid Elastography for Identification of Vulnerable Atherosclerotic Plaques

Ultrasound-based carotid elastography has been developed to evaluate the vulnerability of carotid atherosclerotic plaques. The aim of this study was to investigate the in vivo interoperator reproducibility of carotid elastography for the identification of vulnerable plaques, with high-resolution magnetic resonance imaging (MRI) as reference. Ultrasound radio-frequency data of 45 carotid arteries (including 53 plaques) from 32 volunteers were acquired separately by two experienced operators in the longitudinal view and then were used to estimate the interframe axial strain rate (ASR) with a two-step optical flow method. The maximum 99th percentile of absolute ASR of all plaques in a carotid artery was used as the elastographic index. MRI scanning was also performed on each volunteer to identify the vulnerable plaque. The results showed no systematic bias in the Bland-Altman plot and an intraclass correlation coefficient of 0.66 between the two operators. In addition, no statistical significance was found between the receiver operating characteristic (ROC) curves from the two operators ( ), and their areas under the ROC curves were 0.83 and 0.77, respectively. Using the mean measurements of the two operators as the classification criterion, a sensitivity of 71.4%, a specificity of 87.1%, and an accuracy of 82.2% were obtained with a cutoff value of 1.37 [Formula: see text]. This study validates the interoperator reproducibility of ultrasound-based carotid elastography for identifying vulnerable carotid plaques.

Altered brain volume and its relationship to characteristics of carotid plaques in asymptomatic patients

Carotid plaque is an aggregate marker of exposure to vascular risk factors, which are linked to structural brain changes. We investigated prestroke global and regional changes in brain volume in a carotid plaque population of cognitively healthy individuals and the association between carotid plaque characteristics and these changes.A total of 76 participants were divided into healthy control (HC, n = 28), vulnerable plaque (n = 27) and stable plaque groups (n = 21). All subjects underwent carotid ultrasound and brain magnetic resonance imaging (MRI). Voxel-based morphometry (VBM) was used to examine differences in regional gray matter volumes (rGMVs) among the different groups.The plaque group had a significantly lower mean total cerebral brain volume (TCBV) than the HC group (P = .03). Carotid intima-media thickness (CIMT) was negatively correlated with TCBV (r = -0.311, P = .006) and rGMV in the right thalamus (r = -0.589, P = .001). The rGMVs of the right middle occipital gyrus and bilateral lingual gyrus were significantly different between the unstable and stable groups. The gray-scale median (GSM) of the plaque and the total plaque risk score (TPRS) were correlated with the volume of the right middle occipital gyrus (r=-0.478, P = .001; r = 0.541, P = .001) and bilateral lingual gyrus (r = -0.419, P = .003; r = 0.288, P = .04).Carotid plaque is related to the volume of the brain parenchyma and right thalamus. The rGMVs of the right middle occipital gyrus and bilateral lingual gyrus differed between the vulnerable plaque and stable plaque groups, and the characteristics of carotid plaques may serve as indexes that reflect these changes.

Fractal analysis of plaque border, a novel method for the quantification of atherosclerotic plaque contour irregularity, is associated with pro-atherogenic plasma lipid profile in subjects with non-obstructive carotid stenoses

BACKGROUND AND AIMS

Plaque border irregularity is a known imaging characteristic of vulnerable plaques, but its evaluation heavily relies on subjective evaluation and operator expertise. Aim of the present work is to propose a novel fractal-analysis based method for the quantification of atherosclerotic plaque border irregularity and assess its relation with cardiovascular risk factors.

METHODS AND RESULTS

Forty-two asymptomatic subjects with carotid stenosis underwent ultrasound evaluation and assessment of cardiovascular risk factors. Total, low-density lipoprotein (LDL), high-density lipoprotein (HDL) plasma cholesterol and triglycerides concentrations were measured for each subject. Fractal analysis was performed in all the carotid segments affected by atherosclerosis, i.e. 147 segments. The resulting fractal dimension (FD) is a measure of irregularity of plaque profile on long axis view of the plaque. FD in the severest stenosis (main plaque FD,mFD) was 1.136±0.039. Average FD per patient (global FD,gFD) was 1.145±0.039. FD was independent of other plaque characteristics. mFD significantly correlated with plasma HDL (r = -0.367,p = 0.02) and triglycerides-to-HDL ratio (r = 0.480,p = 0.002).

CONCLUSIONS

Fractal analysis is a novel, readily available, reproducible and inexpensive technique for the quantitative measurement of plaque irregularity. The correlation between low HDL levels and plaque FD suggests a role for HDL in the acquisition of morphologic features of plaque instability. Further studies are needed to validate the prognostic value of fractal analysis in carotid plaques evaluation.

Clinical significance of the coexistence of carotid artery plaque and white matter disease in patients with symptomatic cerebral infarction

OBJECTIVES

Symptomatic cerebral infarction (CI) can occur in patients without main cerebral artery stenosis or occlusion. This study investigated the unique features of carotid artery plaque and white matter disease (WMD) in patients with symptomatic CI and transient ischemic attack (TIA) but without stenosis or occlusion of a main cerebral artery.

PATIENTS AND METHODS

We studied 647 patients who underwent both carotid ultrasound examination and brain magnetic resonance images. Plaque score (PS), plaque number, maximal plaque intima-media thickness and grades of WMD were examined. Subjects were divided into four groups, the CI group, TIA group, myocardial infarction (MI) group and risk factor (RF) group. Plaque and WMD were analyzed in cerebral ischemia group (CI and TIA), compared to non-cerebral ischemia groups and to a high PS group and a high WMD grade group from the RF group.

RESULTS

Both of each value of plaque and grades of WMD in the cerebral ischemia group were significantly higher than those in other groups. Grades of WMD in the cerebral ischemia group were significantly higher than those in the high PS group, although there was no significant difference of the each value of plaque between the two groups. The each value of plaque in the cerebral ischemia group was also significantly higher than those in the high WMD grade group, although there was no significant difference of grade of WMD between the two groups.

CONCLUSION

Simultaneous increases in carotid artery plaque and WMD are associated with symptomatic CI, which is not caused by stenosis or occlusion of a main cerebral artery.

Shear Wave Elastography Imaging for the Features of Symptomatic Carotid Plaques: A Feasibility Study

OBJECTIVES

Shear wave elastography (SWE) was performed to evaluate the Young's modulus of carotid plaques in patients presenting with cerebrovascular incidents, to estimate the clinical value and feasibility of this approach.

METHODS

Sixty-one patients (mean age, 65 years; 45 men) underwent common duplex ultrasonic examination and SWE evaluation. The patients were divided into the symptomatic and asymptomatic groups based on the presence of unilateral focal neurological symptoms. Elasticity and echogenicity of the carotid plaque was assessed by Young's modulus and Gray-Weale classification, respectively.

RESULTS

A total of 271 carotid plaques were assessed through duplex ultrasonic examination and SWE imaging. The Bland-Altman test revealed a perfect reproducibility of Young's modulus measurement using SWE. The interframe coefficient of variation was 16% within the 271 plaques. In the 61 representative plaques, significant correlations were found between Gray-Weale classification and mean Young's modulus (r = 0.728, P < .01) when the confounding factors were controlled. The mean Young's modulus of representative plaques in symptomatic group was lower than those in asymptomatic groups (mean Young's modulus: 81 kPa versus 115 kPa; P < .01). Logistic regression combined with receiver operating characteristic analysis suggested increased sensitivity and specificity for the identification of symptomatic carotid plaques when the mean Young's modulus was combined with stenosis rate.

CONCLUSIONS

Shear wave elastography can evaluate the Young's modulus of carotid plaque stably, and could serve as an additional method for the detection of symptomatic carotid plaques, which, in combination with common ultrasound, can promote the efficiency of differentiating symptomatic carotid plaques.

The role of exercise training and the endocannabinoid system in atherosclerotic plaque burden and composition in Apo-E-deficient mice

INTRODUCTION

We investigated the effect of combining exercise training and treatment with an endocannabinoid receptor 1 inhibitor (Rimonabant) on atherosclerosis burden and composition.

METHODS

Forty-eight apolipoprotein E-deficient (ApoE-/-) mice were kept on a 16-week high-fat diet. Mice were then placed on a normal diet and were randomized to the following groups with n=12 mice for 6 more weeks: 1) Control (Co) - no intervention; 2) Exercise (Ex) - exercise training on treadmill; 3) Rimonabant (Ri) - oral administration of rimonabant (10 mg/kg/day); or 4) Rimonabant+Exercise (RiEx) - combination of Ri and Ex groups treatment. At the end, all animals were sacrificed, and blood samples, as well as aortic root specimens, were obtained for histomorphometric analysis and quantification of the serum and plaque content of matrix metalloproteinases (MMPs).

RESULTS

The mean plaque area was significantly smaller (RiEx: 43.18±1.72%, Ri: 44.66±3.1%, Ex: 49±4.10%, Co: 70.43±2.83%) in all active treatment groups relative to the Co group (p<0.01). Conversely, the relative concentrations of collagen and elastin were increased significantly across all treatment groups compared to Co (p<0.05). Immunohistochemical analysis revealed significantly reduced macrophage content within plaques after all interventions, with the most pronounced effect observed after combined treatment (RiEx: 9.4±3.92%, Ri: 15±2.45%, Ex: 19.78±2.79%, Co: 34.25±4.99%; p<0.05). Within plaques, the TIMP-1 concentration was significantly upregulated in exercise-treated groups. MMP-3 and MMP-9 concentrations were equivalently decreased in all three active treatment groups compared to controls (p<0.001).

DISCUSSION

Both exercise and rimonabant treatments induced plaque regression and promoted plaque stability. The combined treatment failed to show additive or synergistic benefits relative to either intervention alone.

Age-associated changes in human carotid atherosclerotic plaques

Little is known about changes in carotid plaque morphology during aging and the possible impact on cardiovascular events. Only few studies addressed so far age-related modifications within atherosclerotic lesions. Therefore, in this work we endeavored to summarize the current knowledge about changing of plaque composition in elderly. The data from hitherto existing studies confirm that atherosclerotic plaques undergo distinct alternations with advanced age. However, the results are often ambiguous and the changes do not seem to be as disastrous as expected. Interestingly, none of the studies could definitely evidence increased plaque vulnerability with advanced age. Nevertheless, based on the previous work showing decrease in elastin fibers, fibroatheroma, SMCs, overall cellularity and increase in the area of lipid core, hemorrhage, and calcification, the plaque morphology appears to transform toward unstable plaques. Otherwise, even if inflammatory cells often accumulate in plaques of younger patients, their amount is reduced in the older age and so far no clear association has been observed between thin fibrous cap and aging. Thus, the accurate contribution of age-related changes in plaque morphology to cardiovascular events has yet to be elucidated. KEY MESSAGES Composition of carotid atherosclerotic lesions changes during aging. These alternations are however, just moderate and depend upon additional variables, such as life style, accompanying disease, genetics, and other factors that have yet to be determined. Based on the current data, the age-associated plaque morphology seems to transform toward vulnerable plaques. However, the changes do not seem to be as disastrous as expected.

Secondary Stroke Prevention: Improving Diagnosis and Management with Newer Technologies

Treatment of hypertension, diabetes, high cholesterol, smoking cessation, and healthy lifestyle have all contributed to the decline in the incidence of vascular disease over the last several decades. Patients who suffer an acute stroke are at a high risk for recurrence. Introduction of newer technologies and their wider use allows for better identification of patients in whom the risk of recurrence following an acute stroke may be very high. Traditionally, the major focus for diagnosis and management has focused on patient history, examination, imaging for carotid stenosis/occlusion, and detection of AF and paroxysmal AF (PAF) with 24-48 h cardiac monitoring. This review focuses on the usefulness of three newer investigative tools that are becoming widely available and lead to better prevention. Continuous ambulatory blood pressure measurements for 24 h or longer and 3D Doppler measures of the carotid arteries provide key useful information on the state of vascular health and enhance our ability to monitor the response to preventive therapies. Furthermore, the detection of PAF can be significantly improved with prolonged cardiac monitoring for 3 weeks or longer, enabling the initiation of appropriate prevention therapy. This review will focus on the potential impact and importance of these emerging technologies on the prevention of recurrent stroke in high-risk patients.

Serum vitamin D level is negatively associated with carotid atherosclerosis in Korean adults

The present study investigated the associations between serum vitamin D levels and carotid intima-media thickness (CIMT), carotid plaque and atherosclerosis in 71 Korean adults. CIMT and the presence of carotid plaque were assessed with a high-resolution B-mode ultrasound system, and carotid atherosclerosis was defined as a mean CIMT value >0.9 mm or the presence of carotid plaque. A vitamin D deficiency was associated with the presence of carotid plaque (adjusted odds ratio [aOR]: 9.25, 95% confidence interval [CI]: 1.52-56.3; p = 0.016). As serum vitamin D levels increased, the presence of high-risk carotid plaque decreased (aOR: 0.84, 95%CI: 0.72-0.99; p = 0.039). Serum vitamin D levels was negatively associated with carotid atherosclerosis (aOR: 0.86, 95%CI: 0.76-0.97; p = 0.018). Further studies are needed to investigate whether vitamin D supplementation would be effective for the prevention of atherosclerosis and cardiovascular diseases.

Evaluation of Carotid Plaque Using Ultrasound Imaging

Traditional risk factors for predicting of cardiovascular disease are not always effective predictors for development of cardiovascular events. This review summarizes several newly developed noninvasive imaging techniques for evaluating carotid plaques and their role in cardiovascular disease risk.

Cardiovascular Imaging for the Primary Prevention of Atherosclerotic Cardiovascular Disease Events

Traditional cardiovascular risk factors have well-known limitations for the accurate assessment of individual cardiovascular risk. Unlike risk factor-based scores which rely on probabilistic calculations derived from population-based studies, coronary artery calcium (CAC) scoring, and carotid ultrasound allow for the direct visualization and quantification of subclinical atherosclerosis with the potential for a more accurate, personalized risk assessment and treatment approach. Among strategies used to guide preventive management, CAC scoring has consistently and convincingly outperformed traditional risk factors for the prediction of adverse cardiovascular events. Moreover, several studies have demonstrated the potential of CAC testing to improve precision for the use of more intensive pharmacologic therapies, such as aspirin and statins, in patients most likely to derive benefit, as compared to atherosclerotic cardiovascular disease risk calculators. By comparison to CAC, the role of carotid ultrasound for the measurement of carotid intima-media thickness (CIMT) remains less well-elucidated but may be significantly improved with the inclusion of plaque screening and novel three-dimensional measurements of plaque volume and morphology. Despite significant evidence supporting the ability of non-invasive atherosclerosis imaging (particularly CAC) to guide preventive management, imaging remains an under-utilized strategy among current guidelines and clinical practice. Herein, we review evidence regarding CAC and carotid ultrasound for patient risk classification, with a comparison of these techniques to currently advocated traditional risk factor-based scores.

Metabolic syndrome showed significant relationship with carotid atherosclerosis

Metabolic syndrome (MetS) is associated with an increased risk of cardiovascular disease. We assessed the associations between MetS and the indicators of carotid atherosclerosis as assessed by ultrasonography taking into consideration of confounders in the general population. A total of 1281 subjects (856 males, 425 females) were included in the present study. The total plaque score and maximum intima-media thickness (IMT) of the carotid arteries were measured as indicators of atherosclerosis. Cardiovascular risk factors were several metabolic components, serum uric acid, serum C-reactive protein (CRP), and lifestyle factors. MetS was defined according to the criteria of the National Cholesterol Education Program. The prevalences of an elevated total plaque score (≥5) and elevated IMT (>1 mm) of the carotid arteries were significantly higher in subjects with MetS as compared to subjects without MetS. Furthermore, a trend was observed towards higher prevalences of these indicators of atherosclerosis as the number of components of MetS increased. Logistic regression analysis revealed a significant association between elevated plaque score and MetS even after adjustments for age, serum uric acid, serum CRP and lifestyle factors in the males. Among the indicators of atherosclerosis assessed by carotid ultrasonography, a significant independent association was observed between the total plaque score and MetS in males in the general population.

Ultrasound speckle tracking for radial, longitudinal and circumferential strain estimation of the carotid artery--an in vitro validation via sonomicrometry using clinical and high-frequency ultrasound

Ultrasound speckle tracking for carotid strain assessment has in the past decade gained interest in studies of arterial stiffness and cardiovascular diseases. The aim of this study was to validate and directly contrast carotid strain assessment by speckle tracking applied on clinical and high-frequency ultrasound images in vitro. Four polyvinyl alcohol phantoms mimicking the carotid artery were constructed with different mechanical properties and connected to a pump generating carotid flow profiles. Gray-scale ultrasound long- and short-axis images of the phantoms were obtained using a standard clinical ultrasound system, Vivid 7 (GE Healthcare, Horten, Norway) and a high-frequency ultrasound system, Vevo 2100 (FUJIFILM, VisualSonics, Toronto, Canada) with linear-array transducers (12L/MS250). Radial, longitudinal and circumferential strains were estimated using an in-house speckle tracking algorithm and compared with reference strain acquired by sonomicrometry. Overall, the estimated strain corresponded well with the reference strain. The correlation between estimated peak strain in clinical ultrasound images and reference strain was 0.91 (p<0.001) for radial strain, 0.73 (p<0.001) for longitudinal strain and 0.90 (p<0.001) for circumferential strain and for high-frequency ultrasound images 0.95 (p<0.001) for radial strain, 0.93 (p<0.001) for longitudinal strain and 0.90 (p<0.001) for circumferential strain. A significant larger bias and root mean square error was found for circumferential strain estimation on clinical ultrasound images compared to high frequency ultrasound images, but no significant difference in bias and root mean square error was found for radial and longitudinal strain when comparing estimation on clinical and high-frequency ultrasound images. The agreement between sonomicrometry and speckle tracking demonstrates that carotid strain assessment by ultrasound speckle tracking is feasible.

Carotid intima-media thickness and plaque in cardiovascular risk assessment

Carotid intima-media thickness (CIMT) has been shown to predict cardiovascular (CV) risk in multiple large studies. Careful evaluation of CIMT studies reveals discrepancies in the comprehensiveness with which CIMT is assessed-the number of carotid segments evaluated (common carotid artery [CCA], internal carotid artery [ICA], or the carotid bulb), the type of measurements made (mean or maximum of single measurements, mean of the mean, or mean of the maximum for multiple measurements), the number of imaging angles used, whether plaques were included in the intima-media thickness (IMT) measurement, the report of adjusted or unadjusted models, risk association versus risk prediction, and the arbitrary cutoff points for CIMT and for plaque to predict risk. Measuring the far wall of the CCA was shown to be the least variable method for assessing IMT. However, meta-analyses suggest that CCA-IMT alone only minimally improves predictive power beyond traditional risk factors, whereas inclusion of the carotid bulb and ICA-IMT improves prediction of both cardiac risk and stroke risk. Carotid plaque appears to be a more powerful predictor of CV risk compared with CIMT alone. Quantitative measures of plaques such as plaque number, plaque thickness, plaque area, and 3-dimensional assessment of plaque volume appear to be progressively more sensitive in predicting CV risk than mere assessment of plaque presence. Limited data show that plaque characteristics including plaque vascularity may improve CV disease risk stratification further. IMT measurement at the CCA, carotid bulb, and ICA that allows inclusion of plaque in the IMT measurement or CCA-IMT measurement along with plaque assessment in all carotid segments is emerging as the focus of carotid artery ultrasound imaging for CV risk prediction.

Thromboxane prostaglandin receptor antagonist and carotid atherosclerosis progression in patients with cerebrovascular disease of ischemic origin: a randomized controlled trial

BACKGROUND AND PURPOSE

Thromboxane prostaglandin receptors have been implicated to be involved in the atherosclerotic process. We assessed whether Terutroban, a thromboxane prostaglandin receptor antagonist, affects the progression of atherosclerosis, as measured by common carotid intima-media thickness and carotid plaques.

METHODS

A substudy was performed among 1141 participants of the aspirin-controlled Prevention of Cerebrovascular and Cardiovascular Events of Ischemic Origin with Terutroban in Patients with a History of Ischemic Stroke or Transient Ischemic Attack (PERFORM) trial. Common carotid intima-media thickness and carotid plaque occurrence was measured during a 3-year period.

RESULTS

Baseline characteristics did not differ between Terutroban (n=592) and aspirin (n=549) treated patients and were similar as in the main study. Mean study and treatment duration were similar (28 and 25 months, respectively). In the Terutroban group, the annualized rate of change in common carotid intima-media thickness was 0.006 mm per year (95% confidence interval, -0.004 to 0.016) and -0.005 mm per year (95% confidence interval, -0.015 to 0.005) in the aspirin group. There was no statistically significant difference between the groups in the annualized rate of change of common carotid intima-media thickness (0.011 mm per year; 95% confidence interval, -0.003 to 0.025). At 12 months of follow-up, 66% of Terutroban patients had no emergent plaques, 31% had 1 to 2 emergent plaques, and 3% had ≥3 emergent plaques. In the aspirin group, the corresponding percentages were 64%, 32%, and 4%. Over time, there was no statistically significant difference in the number of emergent carotid plaques between treatment modalities (rate ratio, 0.91; 95% confidence interval, 0.77-1.07).

CONCLUSIONS

Compared with aspirin, Terutroban did not beneficially affect progression of carotid atherosclerosis among well-treated patients with a history of ischemic stroke or transient ischemic attacks with an internal carotid stenosis <70%.

CLINICAL TRIAL REGISTRATION URL

http://www.controlled-trials.com. Unique identifier: ISRCTN66157730.

Multiple risk factor intervention reduces carotid atherosclerosis in patients with type 2 diabetes

Background

Patients with rapid progression of carotid intima media thickness (CIMT) were shown to have a higher future risk for cardiovascular events.

The aim of this study was to investigate the impact of multiple risk factor intervention on CIMT progression and to establish whether new cardiovascular surrogate measurements would allow prediction of CIMT changes.

Materials and methods

In this prospective, open, 2-years study, we included 97 patients with type 2 diabetes and at least two insufficiently treated cardiovascular risk factors, i.e. HbA_1c > 7.5% (58 mmol/mol); LDL-cholesterol >3.1 mmol/l or blood pressure >140/90 mmHg. Treatment was intensified according to current guidelines over 3 months with the aim to maintain intensification over 2 years.

The primary outcome was the change in CIMT after 2 years. We also assessed markers of mechanical and biochemical endothelial function and endothelial progenitor cells before and after 3 months of treatment intensification. For testing differences between before and after multifactorial treatment measurements we used either the paired student’s t-test or the Wilcoxon signed-rank test, depending on the distribution of the data. Additional, explorative statistical data analysis was done on CIMT progression building a linear multivariate regression model.

Results

Blood glucose, lipids and blood pressure significantly improved during the first 3 months of intensified treatment, which was sustained over the 2-year study duration. Mean CIMT significantly decreased from baseline to 2 year (0.883 ± 0.120 mm vs. 0.860 ± 0.130 mm; p = 0.021). None of the investigated surrogate measures, however, was able to predict changes in IMT early after treatment intensification.

Conclusions

Intensification of risk factor intervention in type 2 diabetes results in CIMT regression over a period of 2 years. None of the biomarkers used including endothelial function parameters or endothelial progenitor cells turned out to be useful to predict CIMT changes.

Trial registration

Clinical Trial Registration – Unique identifier: NCT00660790

Plaque morphology detected with Duplex ultrasound before carotid angioplasty and stenting (CAS) is not a predictor of carotid artery in-stent restenosis, a case control study

Background

In-stent restenosis (ISR) is an important factor endangering the long-term safety and efficacy of carotid artery angioplasty and stenting (CAS). It is plausible that soft vulnerable plaques are more likely to be injured during CAS procedure and are therefore more likely to initiate the cascade finally leading to ISR. The aim of this study was to investigate if plaque morphology detected by a simple applicable Duplex ultrasound score before CAS can be used as a predictor for ISR.

Methods

Within a prospectively collected single-centre CAS database of 281 patients (comprising 300 arteries) with high-grade carotid artery stenosis, who underwent CAS between May 2003 and January 2013, we conducted a nested case–control study. Plaque morphology before CAS was analysed by a blinded investigator and each parameter of the Total Plaque Risk Score (TPRS) as well as the whole score was evaluated with regard to its diagnostic validity for ISR.

Results

We analysed the data of 10 patients with ISR and 50 patients without ISR. There were no significant differences with respect to baseline characteristics, vascular risk factors, and degree of stenosis between patients with and without ISR. The duration of follow-up was longer in patients with ISR (p = 0.024) and these patients were more likely to show increased PSV (p = 0.012) immediately after CAS than patients without ISR. Neither individual parameters of the TPRS score nor the score as a whole were suitable as a diagnostic test for ISR development.

Conclusions

In the present study we could demonstrate that the non-contrast enhanced DUS of the pre-interventional plaque formation cannot be used as a predictor for the development of ISR. Evaluating a more sophisticated, but not routinely available approach e.g. by ultrasound based plaque perfusion imaging or CT based plaque analysis could be helpful in the future in order to assess the role of plaque morphology in the context of ISR development.

Ultrasonography of carotid plaque for the prevention of stroke

A carotid ultrasonography is a non-invasive technique that provides an accurate and reliable characterization of the broad spectrum of carotid arteriosclerosis, from the intima-media thickness to the atherosclerotic plaque. Carotid ultrasonography has become a useful tool for identifying patients at high risk of stroke and selecting those who can benefit most from revascularization therapies such as carotid endarterectomy and stenting. In addition to the degree of stenosis, plaque echomorphology has emerged in recent years as an important contributory factor to stroke risk. Changes in plaque echogenicity, as measured by the quantitative computer-assisted ultrasonography index, could be a marker of plaque instability as well as an indicator of plaque remodeling, thereby providing the means for monitoring anti-atherosclerosis drugs such as statins.

Comparison between proximal versus distal protection devices in 287 cases of carotid revascularization using angioplasty and stenting: periprocedure complications, morbidity, and mortality

BACKGROUND

Embolic protection devices may decrease periprocedural thromboembolic complications during carotid angioplasty and stenting (CAS). When using proximal-protection devices (PPDs), protection starts before crossing the lesion. However, in the medical literature, its use is scarcely reported compared with that of distal-protection filters (DPDs). The objective of this study was to compare periprocedure complications, morbidity, and mortality among 287 consecutive cases of CAS performed with PPDs or DPDs.

PATIENTS AND METHODS

This was a retrospective analysis of 287 patients treated with CAS at our hospital between January 2006 and March 2012. Periprocedure complications, morbidity, and mortality at 30 days, including ischemic stroke or transient ischemic attack, reperfusion syndrome, myocardial infarction (MI), and death, were globally registered, and the results in PPD and DPD groups were compared.

RESULTS

Two hundred eight patients were treated with DPD and 79 with PPD; 80.8 % were symptomatic. CAS procedures performed with PPD presented a statistically significant greater grade of stenosis than those with DPD (82.5 vs. 74.5 %, p < 0.001). Death rates were 1.9 and 1.3 %; stroke rates were 4.3 and 3.8 %; MI rates were 1.4 and 1.3 %; and total morbidity and mortality rates were 6.2 and 5 % (DPD and PPD groups, respectively); all differences were nonstatistically significant. No statistical difference was found between symptomatic and asymptomatic patients.

CONCLUSION

Carotid angioplasty and stenting is a safe procedure to treat carotid disease in our patients. PPDs are not always associated with a greater risk of periprocedure complications, morbidity, and mortality than DPDs despite the greater grade of carotid stenosis in the PPD group. This observation may be of interest in the design of future studies with CAS.

Increased carotid intima-media thickness and plasma homocysteine levels predict cardiovascular and all-cause death: a population-based cohort study

BACKGROUND

There is still debate over the utility of carotid intima-media thickness (C-IMT) or carotid plaque in predicting future cardiovascular events and death. Additionally, the importance of plasma homocysteine levels was raised as a predictor of cardiovascular events and death.

METHODS

1,391 subjects were recruited from the Ansan Geriatric cohort. We used B-mode carotid ultrasonography to assess C-IMT and plaque, measuring average maximal IMT and average mean IMT through 6-8 measurements of far-wall IMT in both common carotid arteries. We evaluated the presence of plaque in carotid segments. Multivariable Cox regression analysis was used to predict both cardiovascular and all-cause mortality.

RESULTS

During a mean follow-up of 62.4 ± 12.4 months, 71 subjects (5.12%) died and 23 (1.66%) died of cardiovascular causes. Multivariable Cox regression analysis found the predictors of cardiovascular mortality to be average maximal IMT (HR = 3.709; 95% CI: 1.202-11.446) and plasma homocysteine (HR = 1.057; 95% CI: 1.012-1.103). All-cause mortality was independently associated with C-IMT (average maximal and average mean IMT) and plasma homocysteine.

CONCLUSIONS

C-IMT and plasma homocysteine levels were found to predict cardiovascular and all-cause mortality independently of the presence of carotid plaque and other cardiovascular risk factors.

Ultrasonographic markers of vascular risk in patients with asymptomatic carotid stenosis

Six-hundred twenty-one subjects with unilateral asymptomatic severe internal carotid artery (ICA) stenosis were prospectively evaluated with a median follow-up of 27 months (min=6, max=68). Vascular risk profile, plaque characteristic, stenosis progression, and common carotid artery intima-media thickness (IMT) were investigated in all patients. Outcome measures were occurrence of ischemic stroke ipsilateral to ICA stenosis and vascular death, while myocardial infarction, contralateral strokes, and transient ischemic attack were considered as competing events. A total of 99 subjects (15.9%) suffered from a vascular event. Among them, 39 were strokes ipsilateral to the stenosis (6.3%). Degree of stenosis, stenosis progression, and common carotid artery IMT resulted as independent predictive factors of ipsilateral stroke. Considering a stenosis of 60% to 70% as reference, a degree between 71% and 90% increased the risk by 2.45, while a degree between 91% and 99% increased the risk by 3.26. The progression of stenosis was a strong risk factor (hazard ratio=4.32). Finally, the role of carotid IMT was confirmed as crucial additional measure, with an increased risk by 25% for each 0.1 mm IMT increase. Our data suggest that IMT, stenosis progression and severity should be considered as risk factors for cerebrovascular events in asymptomatic subjects with severe ICA stenosis.

Correlation between frequency of microembolic signals and efficacy of antiplatelet therapy in symptomatic carotid disease

BACKGROUND AND PURPOSE

The detection of microembolic signals in transcranial-Doppler monitoring is associated with a higher stroke risk. We investigated the correlation between the frequency of microembolic signals and the efficacy of the antiplatelet therapy in patients with a recent symptomatic carotid-artery stenosis.

SUBJECTS AND METHODS

Thirty-two patients (mean age: 70 years, 22 men) with a recent symptomatic carotid-artery stenosis underwent 30-minute TCD-monitoring. Twenty-three patients received acetylsalicylic-acid and 9 patients clopidogrel as antiplatelet-therapy. At the same day, the antiplatelet effect was measured with multiple-electrode-impedance aggregometry.

RESULTS

In 20 cases, the qualifying event was a stroke and in 12 cases, a TIA. Twenty-six of the patients had a >50% degree of stenosis. More than one microembolic signals were detected in 13 (40.6%) of the subjects, while multiple-electrode-impedance aggregometry revealed eight low responders (6 acetylsalicylic-acid, 2 clopidogrel). More than one microembolic signals were detected in 6 of the 8 (75.0%) patients with low response, but in only 7 of the 24 subjects (29.2%) with an effective antiplatelet treatment (sensitivity 75%, specificity 70.8%; Fisher's exact test: P = .038).

CONCLUSIONS

Our study suggests that in patients with recent symptomatic carotid-artery stenosis the detection of more than one microembolic signals might serve as a useful marker for the effectiveness of the antiplatelet treatment.

Association between variations in coagulation system genes and carotid plaque

OBJECTIVE

Genetic variation in coagulation and fibrinolysis may affect the development of subclinical atherosclerosis modifying the risk of stroke and cardiovascular disease. However, data on the relationship between subclinical atherosclerosis and genes involved in the coagulation system are sparse. The objective of this study is to examine the association between single nucleotide polymorphisms (SNPs) in coagulation system genes and subclinical carotid plaque phenotypes.

METHODS

From the Genetic Determinants of Subclinical Carotid Disease Study, 287 Dominicans were examined for carotid plaque presence, thickness, and surface irregularity by high-resolution B-mode carotid ultrasound. Logistic regression was used to test for association between 101 SNPs in 23 coagulation system genes and plaque phenotypes while controlling for age, sex, smoking, hypertension, dyslipidemia, and diabetes. Within gene haplotypes and interactions between genes were examined. A follow-up of SNPs in moderate to high (r(2)>0.25) linkage disequilibrium (LD) with those implicated in the discovery analysis (p ≤ 0.01) was performed in an independent sample of 301 Dominicans.

RESULTS

The prevalence of carotid plaque (47% discovery; 46% follow-up) as well as the mean age (65 ± 8 discovery; 65 ± 9 follow-up) of the participants was similar in both datasets. Two genes (vWF and THBS1) were associated (p ≤ 0.01) with plaque size and surface irregularity. In follow-up, 5 SNPs in vWF were associated (p ≤ 0.05) with plaque size. SERPINE1 was an additional gene of interest in the haplotype and interaction analyses.

CONCLUSIONS

Variation in the vWF, THBS1, and SERPINE1 gene may play an important role in the pathogenesis of atherosclerotic plaque.

Sonographic characteristics of carotid artery plaques: Implications for follow-up planning?

The aim of our study was to analyze the ultrasound characteristics of carotid plaques in an outpatient population and to determine their implications for planning the ultrasound follow-up.

MATERIALS AND METHODS

We studied 747 consecutive outpatients (397 [53%] of whom were women) who underwent color Doppler sonography of the carotid arteries. Most of the patients presented multiple cardiovascular risk factors or were being followed-up for carotid artery stenosis.

RESULTS

Stenosis ranging from 1% to 69% was observed at the level of the right internal carotid arteries (ICA) in 419 (56.1%) of the 747 patients and in the left ICA in 408 of 747 (54.5%). One hundred twenty-four (29.5%) of the 419 RICA plaques and 77 (18.8%) of the 408 LICA plaques were classified as type 1 or type 2 according to the modified Gray-Weale classification.

CONCLUSIONS

Type 1 and type 2 plaques, which are referred to as "vulnerable plaques," were found in 160 (21.4%) of the 747 patients we examined. These patients should be subjected to closer ultrasound follow-up, even if they have only moderate carotid artery stenosis.

Identification of high-risk carotid artery stenosis: motion of intraplaque contents detected using B-mode ultrasonography

Object

Identification of the risk of rupture and vulnerability of arterial plaque is not yet clearly understood. The aim of this study was to assess the clinical features of the motion of intraplaque contents (MIC) detected by B-mode ultrasonography. The MIC is characterized by the peculiar movement of the intraplaque contents that is not synchronized with the heartbeat; however, the movement of the carotid artery (CA) wall depends on the heartbeat.

Methods

From January 2008 to November 2010, 1798 consecutive patients with transient ischemic attacks (TIAs) or acute ischemic stroke underwent CA ultrasonography for the examination of the MIC. Patients with CA stenosis greater than 50% were followed up until they underwent carotid endarterectomy or CA angioplasty and stent placement. If neither of these procedures were used, the patients were followed up at 90 days. Chi-square and Mann-Whitney tests were performed to compare the categorical and continuous demographic data and risk factors. The effect of the MIC on the rate of recurrent cerebral ischemia was examined using Kaplan-Meier and univariate Cox regression analyses.

Results

One hundred and fifteen patients had CA stenosis greater than 50%. Among these 115 patients, 58 with a total of 59 CA stenoses had MIC. Twenty-four recurrent ischemic events were associated with MIC, whereas only 6 such events occurred in the absence of MIC. The MIC decreased event-free survival (log-rank test = 15.8, p < 0.001); univariate Cox analysis confirmed that MIC increased the risk of a recurrent ischemic event (HR 5.12, 95% CI 2.08–12.58; p < 0.001).

Conclusions

The MIC is one of the findings of vulnerable plaques. The MIC is more useful in predicting the recurrence of TIAs or ischemic events in patients with symptomatic CA stenosis.

Accuracy of a Novel Risk Index Combining Degree of Stenosis of the Carotid Artery and Plaque Surface Echogenicity

Background and Purpose—

The purpose of this study was to determine the accuracy of a risk index in symptomatic or asymptomatic carotid stenoses.

Methods—

Consecutive patients presenting 50% to 99% carotid stenoses were included. A semiautomated gray scale-based color mapping (red, yellow, and green) of the whole plaque and of its surface was achieved. Surface was defined as the region located between the lumen (Level 0) and, respectively, 0.5, 1, 1.5, and 2 mm. Risk index was based on a combination of degree of stenosis and the proportion of the red color (reflecting low echogenicity) on the surface or on the whole plaque.

Results—

There were 67 (36%) symptomatic and 117 (64%) asymptomatic carotid stenoses. Risk index values were higher among symptomatic stenoses (0.46 mean versus 0.29; P <0.0001); on receiver operating characteristic curves, risk index presented a stronger predictive power compared with degree of stenosis or surface echogenicity alone. Also, in a regression model including age, gender, degree of stenosis, surface echogenicity, gray median scale of the whole plaque, and risk index, risk index measured within the surface region located at 0.5 mm from the lumen was the only parameter significantly associated with the presence of symptoms (OR, 4.89; 95% CI, 2.7–8.7; P =0.0000002). The best criterion to differentiate between symptomatic and asymptomatic stenoses was a risk index value >0.36 (sensitivity and specificity of 78% and 65%, respectively).

Conclusions—

Risk index was significantly higher in the presence of symptoms and could therefore be a valuable tool to assess the clinical risk of a carotid plaque.

Advances in noninvasive imaging for evaluating clinical risk and guiding therapy in carotid atherosclerosis

Managing asymptomatic carotid atherosclerosis with a view to preventing ischemic stroke is a challenging task. As the annual risk of stroke in untreated asymptomatic patients on average is less than the risk of surgical intervention, the key question is how to identify those asymptomatic individuals whose risk of stroke is elevated and who would benefit from surgery, while sparing low-risk asymptomatic patients from the risks of surgical intervention. The advent of a multitude of noninvasive carotid imaging techniques offers an opportunity to improve risk stratification in patients and to monitor the response to medical therapies; assessing efficacy at individual and population levels. As part of this, plaque measurement techniques (using ultrasound, computed tomography or MRI) may be employed in monitoring plaque/component regression and progression. Novel imaging applications targeted to plaque characteristics, inflammation and neovascularization, including contrast-enhanced ultrasound and MRI, dynamic contrast-enhanced MRI, and fluorodeoxyglucose-PET, are also being explored. Ultimately, noninvasive imaging and other advances in risk stratification aim to improve and individualize the management of patients with carotid atherosclerosis.

Improving atherosclerosis risk assessment: looking beyond plaque accumulation to imaging of embolization and healing

Cerebrovascular and cardiovascular diseases constitute the most substantial disease burden worldwide and are only increasing in importance. Understanding how individuals with atherosclerosis may be better assessed for risk of stroke and myocardial infarction will have immense importance in deciding on therapeutic options. Carotid atherosclerosis is frequently portrayed as an orderly progression from asymptomatic plaque formation that enlarges with aging and culminates in either stable, calcified plaque or vulnerable, ruptured and inflamed plaque. New evidence suggests that atherosclerosis is better described as an equilibrium between synthetic and degradative processes. Putatively, plaques heal and decrease in size through processes such as efferocytosis in individuals unlikely to experience symptoms, whereas individuals who experience symptoms lack reparative mechanisms. Present clinically employed imaging strategies overlook plaque healing mechanisms. Other approaches that examine the downstream effects of plaque, rather than static plaque measurement, such as ultrasound emboli signal detection may address the gap between plaque that is vulnerable in appearance and that which is actually likely to cause symptoms. To ascertain the clinical risk of atherosclerosis optimally, both sides of the equation must be examined instead of relying on a unidirectional accumulative approach to atherosclerosis.

Basal Cerebral Computed Tomography as Diagnostic Tool to Improve Patient Selection in Asymptomatic Carotid Artery Stenosis

One-hundred patients were included to evaluate the role of cerebral computed tomography (CT) to improve patient selection in asymptomatic internal carotid stenosis. Symptomatic patients were assigned to group A, asymptomatic patients to group B. A cerebral CT pattern A was observed in groups A and B in 60% and 20%, respectively ( P < .0001). Between A and B groups, type 6 plaques were found, respectively, in 26.7% and 7.5% of patients ( P = .01); a type 5 in 51.7% and 45% ( P = .32) of patients; and a type 4 in 21.7% and 47.5% of patients, respectively ( P = .006). Within B group, the association of CT pattern A and histological plaque level 4, 5, and 6 was, respectively, 25% ( P = .15), 50% ( P = .53), and 25% ( P = .16). In group B, a 7-fold risk increase in CT pattern A was found in patients with level 6 plaque. In asymptomatic patients with high-risk plaque, a basal cerebral CT scan can be used as diagnostic tool to improve patient selection for intervention.