Bilateral common carotid artery ultrasound for prediction of incident strokes using intima-media thickness and external diameter: an observational study

Sex-specific prediction value of common carotid artery diameter for stroke risk in a hypertensive population: a cross-sectional study

BACKGROUND

The importance of sex as a risk factor for stroke has been established. This study aimed to assess sex-related disparities in carotid artery diameter and stroke in a hypertensive population.

METHODS

The cross-sectional survey was conducted in rural areas of northeast China. A multistage cluster sampling method was employed to select a representative population. The study comprised 3,245 individuals with hypertension. The common carotid artery (CCA) interadventitial diameter was measured by ultrasound. A linear model of restricted cubic spline function was used to characterize the concentration-response (C-R) relationship between CCA diameter and stroke.

RESULTS

The overall prevalence of stroke was 8.9% among hypertensive individuals, with a higher rate in men than in women (10.8% vs. 7.6%). When the women's CCA diameters were divided into quartiles, the top quartile (>8.10 mm) had a 2.49 (95% CI: 1.36-4.56) times greater risk of stroke compared to the bottom quartile (≤6.80 mm) after adjustment was made for other variables. The C-R relationship further confirmed a positive association between CCA diameter and stroke prevalence in women. Moreover, a category-free net reclassification index (0.325; 95% CI: 0.173-0.476; P<0.001) and an integrated discrimination index (0.008; 95% CI: 0.004-0.012, P<0.001) showed improvement in predicting the probability of stroke from CCA diameter. However, no significant relationship between CCA diameter and prevalence of stroke was found in men.

CONCLUSIONS

The risk of stroke increased proportionally with the enlargement of the CCA diameter in women, supporting the sex-specific value of CCA diameter in optimizing the risk stratification of stroke.

Comparison of the Characteristics and Risk Factors of Carotid Atherosclerosis in High Stroke Risk Populations Between Urban and Rural Areas in North China

Objective: To study the characteristics and risk factors of carotid atherosclerosis in populations at high risk of stroke in urban and rural areas of North China. Methods: A cross-sectional study was conducted to investigate high stroke risk populations in representative urban and rural areas sampled from 12 regions of China. A pre-designed questionnaire, ultrasound, and laboratory examinations were performed to evaluate risk factors. Results: A total of 30,175 patients were included in the study. The overall prevalence of carotid atherosclerosis was 54.53%, among which intimal thickening and plaque were 39.22 and 41.25%, respectively. The prevalence of carotid atherosclerosis in the urban group was higher than in the rural group. Multivariate logistic regression analysis revealed that male gender, age, smoking, hypertension, dyslipidemia, stroke, atrial fibrillation, systolic blood pressure, and levels of fasting blood glucose, total cholesterol, and low-density lipoprotein cholesterol were the common independent risk factors for carotid atherosclerosis in both groups. Higher education, high salt consumption, passive smoking, family history of stroke, and transient ischemic attack were unique independent risk factors, and high-density lipoprotein cholesterol was a protective factor for carotid atherosclerosis in the urban population. Conclusion: This study suggests that risk factors for carotid atherosclerosis differ between urban and rural populations in North China.

Usefulness of Carotid Ultrasonography for Risk Stratification of Cerebral and Cardiovascular Disease

Carotid ultrasonography is useful for the assessments of the risk stratification for stroke or coronary artery disease, because it is a simple, repeatable, and noninvasive procedure. The carotid intima-media thickness (IMT), which is assessed using carotid ultrasonography, is a widely used surrogate marker for the severity of atherosclerosis. Several large clinical studies showed that increased carotid IMT is associated with the future stroke or cardiovascular events. In addition, in many clinical trials, it has been adopted for surrogate markers of clinical endpoints of medical intervention. Moreover, carotid ultrasonography allows the measurement of the presence and characteristics of plaques and the severity of carotid artery stenosis. The unstable morphology of plaque, such as hypoechoic, ulcer, and mobility, is associated with future ischemic stroke events. The screening tool of asymptomatic carotid artery stenosis is also important, although whether routine carotid ultrasonography assessment is recommended in the general population remains controversial. The screening of carotid artery stenosis using ultrasonography is essential for not only daily clinical settings but also management of patients with acute ischemic stroke. The patients with atherothrombotic stroke with severe internal carotid artery stenosis should be considered to surgical intervention, and duplex ultrasound approach is important to estimate for the severity of carotid stenosis. Physicians should keep in mind the usefulness of carotid ultrasonography for risk stratification of cerebral and cardiovascular disease based on various aspects. In addition, visual assessment or dynamic changes using carotid ultrasonography could provide the various and valuable insights in clinical settings.

Carotid Lumen Diameter Is Associated With All-Cause Mortality in the General Population

Background

Common carotid intima–media thickness (cIMT) is a biomarker for subclinical atherosclerosis and is associated with all‐cause as well as cardiovascular mortality. Higher cIMT is accompanied by a compensatory increase in lumen diameter (LD) of the common carotid arteries. Whether cIMT or LD carry more information with regard to mortality is unclear.

Methods and Results

A total of 2751 subjects (median age 53 years; 52% female) were included. During a median follow‐up of 14.9 years (range: 12.8–16.5) a total of 506 subjects died. At baseline, cIMT and LD were assessed by carotid ultrasound scans. Multivariable Cox regression models were used to relate cIMT, LD, LD adjusted for cIMT (LD+cIMT), and LD/cIMT ratio with all‐cause, cardiovascular, and noncardiovascular mortality. All models were ranked using Akaike's information criterion. Harrel's c statistic was used to compare the models' predictive power for mortality. A 1‐mm increase in LD was related to a higher risk for all‐cause mortality (hazard ratio [HR], 1.29; 95% CI, 1.14–1.45, P<0.01). This association remained significant when cIMT was added to the model (HR, 1.26; 95% CI, 1.11–1.42; P<0.01). A 1‐mm higher cIMT was also related with greater mortality risk (HR, 1.73; 95% CI, 1.09–2.75). The LD/cIMT ratio was not associated with all‐cause mortality. LD had the lowest Akaike's information criterion regarding all‐cause mortality and improved all‐cause mortality prediction compared with the null model (P=0.01). CIMT weakened all‐cause mortality prediction compared with the LD model.

Conclusions

LD provided more information for all‐cause mortality compared with cIMT in a large population‐based sample.

Vascular deformation in human atherosclerotic carotid artery evaluated by 2D analysis of ultrasonography

OBJECTIVES

Common carotid artery (CCA) remodelling in the atherosclerosis process is an inherent necessary element that decreases the progress of significant lumen compromise. The present study used a semi-automated method to assess relationships of intima-media thickness (IMT), lumen diameter (LD) and inter-adventitial diameter (IAD) using ultrasound B-mode images of atherosclerotic carotid artery.

METHODS

In the cross-sectional study, 120 male subjects (age range: 40-60 years) were classified into four research groups namely control, mild, moderate, and severe stenosis. The maximum near and far wall IMT, mean of both walls' IMT and IAD, and also LD of the left CCA were extracted for all participants. Pearson correlation coefficient was utilized to investigate relationships of IMT, LD, and IAD.

RESULTS

Results revealed that the maximum far and near wall IMT, mean of both walls' IMT and IAD in the CCA were significantly different in stenosis patients and the control group (p< 0.001). However, there were no significant differences among the four studied groups in terms of LD of CCA (p = 0.65). There was a stronger correlation between mean of both walls' IMT and IAD in comparison with mean far wall IMT and IAD (p < 0.001).

CONCLUSIONS

Results indicated that changes of IAD in the left CCA were associated with carotid deformation, and thus it can be considered as a predictor of atherosclerosis process.

Neurological complications after cardiac surgery: a retrospective case-control study of risk factors and outcome

Background

To evaluate incidence, risk factors, and outcomes of postoperative neurological complications in patients undergoing cardiac surgery.

Methods

A total of 2121 patients underwent cardiac surgery between August, 2008 and December, 2013; 91/2121 (4.3%) underwent brain computed tomography (70/91, 77%) or magnetic resonance imaging (21/91, 23%) scan because of major stroke (37/2121, 1.7%) and a spectrum of transient neurological episodes as well as transient ischemic attacks and delirium /psychosis/seizures (54/2121, 2.5%). The mean age was 65.3 ± 12.1 years and 60 (65.9%) were male. Variables were compared among study- and matched-patients (n = 113) without neurological deficits.

Results

A total of 37/2121 (1.7%) patients had imaging evidence of stroke. Radiological examinations were done 5.72 ± 3.6 days after surgery. Patients with and without imaging evidence of stroke had longer intensive care unit length of stay (LOS) (13.8 ± 14.7 and 12.9 ± 15 days vs. 5.7 ± 12.1 days, respectively (p < 0.001) and hospital LOS (53 ± 72.8 and 35.5 ± 29.8 days vs. 18.4 ± 29.2 days, respectively (p < 0.001) than the control group. The hospital mortality of patients with and without imaging evidence of stroke was higher than the control group (7/37 patients [19%], and 12/54 patients [22%] vs. 4/115 patients [3%], respectively (p < 0.001). Multivariate analysis showed that bilateral internal carotid artery stenosis of any grade (p < .001), and re-do operations (p = .013) increased the risk of postoperative neurological complications.

Conclusions

Neurological complications after cardiac surgery increase hospitalization and mortality even in patients without radiologic evidence of stroke. Bilateral internal carotid artery stenosis of any grade, suggesting a diffuse patient propensity toward atherosclerosis, and re-do operations increase the risk of postoperative neurological complications.

Matrix Metalloproteinase-1 Gene Polymorphism Associated with Ultrasound-Assessed Carotid Thickness among Older Adults

BACKGROUND AND AIM

Due to the high incidence of vascular diseases, it is necessary to identify new circulating or structural markers for predicting risk for chronic diseases. Some studies suggest that MMP1 gene polymorphisms are associated with the enzyme expression levels in situ (e.g., in atherosclerotic plaques).

OBJECTIVES

Thus, the study of this polymorphism may help understanding the pathophysiology of coronary disease.

METHODS

We performed cross-sectional clinical and laboratory evaluations (including measurement of intima-media thickness of carotid arteries) and genotyping of the MMP1 SNP rs495366 (A/G) in 366 elderly people.

RESULTS

No significant differences between genotypes were noted for biochemical, metabolic, inflammatory, or clinical variables except for a significant difference in intima-media thickness for the left carotid artery and a trend toward significance for the right counterpart.

CONCLUSION

Carriers of the allele associated with lower MMP1 expression (allele A) presented greater carotid thickness. We suggest that the phenomenon can be explained by impaired remodeling of the arterial wall (poor degradation of collagen fibers in this scenario), yielding carotid wall thickening and a greater intrinsic risk for cerebrovascular events.

Effects of Cilnidipine, an L/N-Type Calcium Channel Blocker, on Carotid Atherosclerosis in Japanese Post-Stroke Hypertensive Patients: Results from the CA-ATTEND Study

Aims: Although several antihypertensive agents reduced the carotid intima-media thickness (IMT), it remains unclear whether those agents affect the interadventitial diameter (IAD). We aimed to examine whether cilnidipine, an L/N-type calcium channel blocker, reduced the common carotid IMT or IAD in post-stroke hypertensive patients.

Methods: The common carotid IMT and IAD were measured at the start of cilnidipine treatment and 12 months from that. The changes in the mean max-IMT or IAD between baseline and the 12-month follow-up were evaluated and compared between the thick group (max-IMT ≥ 1.1 mm) and the normal group (max-IMT < 1.1 mm).

Results: A total of 603 post-stroke hypertensive subjects (mean age = 69.3 yr, 378 males) were included in the analysis. At baseline, IAD was increased stepwise according to the value of max-IMT (p for trend < 0.001). Among them, 326 subjects were followed up for 12 months. The mean max-IMT from baseline to 12 months did not change in the normal group (−0.01 mm, 95% confidence interval [CI] −0.03 to 0.01, n = 170), whereas a significant reduction was observed in the thick group (−0.09 mm, 95% CI −0.13 to −0.05, n = 156). The mean IAD was significantly reduced during the study period in the normal group (−0.14 mm, 95% CI −0.22 to −0.05) as well as in the thick group (−0.12 mm, 95% CI −0.21 to −0.03).

Conclusions: Cilnidipine promoted the regression of common carotid IMT in post-stroke hypertensive patients, especially in the thick group. Cilnidipine also reduced the IAD in both normal and thick groups.

Common Carotid Artery Diameter and Risk of Cardiovascular Events and Mortality: Pooled Analyses of Four Cohort Studies

Carotid arterial diameter enlargement is a manifestation of arterial remodeling and may be a risk factor for cardiovascular disease (CVD). We evaluated the association between carotid artery diameter and risk of stroke, coronary heart disease, CVD, and all-cause mortality and explored whether the associations could be explained by processes involved in arterial remodeling, that is, blood pressure-related media thickening, arterial stiffness, arterial wall stress, and atherosclerosis. We included 4887 participants (mean age 67±9 years; 54% women) from 4 cohort studies: Rotterdam Study, NEPHROTEST, Hoorn Study, and a study by Blacher et al. Common carotid artery properties were measured using echotracking. Incident cases were recorded based on medical records. We used Cox proportional hazard models adjusting for cardiovascular risk factors and estimates of processes underlying arterial remodeling. During follow-up (mean, 11 years), 379 (8%) individuals had a stroke, 516 had a (11%) coronary heart disease, 807 had a (17%) CVD, and 1486 (30%) had died. After adjustment for cardiovascular risk factors, individuals in the highest tertile of carotid diameter (diameter >8 mm) compared with those in the lowest tertile (diameter <7 mm) had a higher incidence of stroke (hazard ratio, 1.5; 95% confidence interval, 1.1-2.0). From all estimates of processes underlying arterial remodeling, adjustment for carotid intima-media thickness attenuated this association (hazard ratio after adjustment for intima-media thickness, 1.2; 95% confidence interval, 0.9-1.6). Larger carotid diameter was associated with risk of CVD and mortality but not clearly with coronary heart disease risk. We showed that a larger carotid diameter is associated with incident stroke, CVD, and mortality. Carotid intima-media thickness, a measure of blood pressure-related media thickening, partially explained the association with stroke incidence.

Age-Wise Association of Carotid Intima Media Thickness in Ischemic Stroke

BACKGROUND

Ischemic stroke is often a sequel of atherosclerotic risk factors. Carotid intima-media thickness (CIMT) is a surrogate marker of early atherosclerotic changes.

PURPOSE

It was hypothesized that CIMT is associated with ischemic stroke in adults across all ages.

METHODS

A case control study was performed on 163 diagnosed cases of first-time ischemic stroke and age-(±1 SD) and gender-matched healthy control attendants reporting at a tertiary care hospital. Data were collected on atherosclerotic risk factors for ischemic stroke. CIMT from both the carotids was measured using carotid vascular Doppler. The demographic profile and CIMT with atherosclerotic risk factors of cases and controls across different age groups were compared using unpaired t test if they passed the test of normality, else the Mann-Whitney test was used. OR for vascular risk factors for the development of stroke was calculated. The relationship of CIMT to atherosclerotic risk factors was analyzed by using Spearman correlation and regression analysis. The level of significance was set at 0.05.

RESULTS

Age-specific value of CIMT was significantly higher in stroke cases than in age-matched controls across all age groups. Right CIMT, along with the history of hypertension (HTN; OR 2.3), are important risk factors for ischemic stroke in the younger age group (20-40 years). With increasing age along with the history of HTN and right CIMT (OR >7), presence of plaque (OR 6.3) and daily smoking (OR 5.1) are also significant risk factors. CIMT is significantly related to the daily alcohol and smoking intake and the presence of plaques. Right CIMT is positively related to increasing age in normal population (R² = 0.041; p < 0.001).

CONCLUSIONS

Right CIMT and comorbid HTN are significant risk factors associated with the development of ischemic stroke across all adult age groups.

Thicker carotid intima-media thickness and increased plasma VEGF levels suffered by post-acute thrombotic stroke patients

Background and objectives

Atherosclerosis causes reduction of the oxygen supply to structures in the far arterial wall, provoking the release of factors that drive angiogenesis of vasa vasorum, including VEGF. Other studies have revealed the inflammatory response in atherosclerosis and the role of platelet factor 4 (PF4) as an anti-angiogenic chemokine through the inhibition of VEGF. This cross-sectional study aims at measuring the effect of atherosclerosis assessed through carotid intima-media thickness (CIMT) against plasma VEGF levels in patients with post-acute thrombotic stroke.

Materials and methods

CIMT was assessed sonographically using GE Logiq S6 with 13 MHz frequency linear probe. VEGF-A plasma levels were measured using enzyme-linked immunosorbent assay (ELISA) method. Differences among variables were compared statistically. The data were analyzed using Pearson correlation.

Results

A total of 25 patients with post-acute thrombotic stroke were identified in days 7 to 90. CIMT thickening was indicated in 88% of patients (1.202 ± 0.312 mm), while an increase in plasma VEGF was identified in all patients (178.28 ± 93.96 ng/mL). There was no significant correlation between CIMT and plasma VEGF levels in patients with post-acute thrombotic stroke (p=0.741). A significant correlation was recognized between CIMT and total cholesterol (p=0.029) and low-density lipoprotein (p=0.018).

Conclusion

There were no significant correlations between CIMT and plasma VEGF levels in patients with post-acute thrombotic stroke. However, plasma VEGF increased in patients with thrombotic stroke. CIMT measurement is a promising noninvasive modality to assess the vascular condition of patients with stroke and diabetes, while plasma VEGF cannot specifically assess vascular condition as it can be triggered by ischemic conditions in tissues of the whole body.

Brain Arterial Diameters as a Risk Factor for Vascular Events

Background

Arterial luminal diameters are routinely used to assess for vascular disease. Although small diameters are typically considered pathological, arterial dilatation has also been associated with disease. We hypothesize that extreme arterial diameters are biomarkers of the risk of vascular events.

Methods and Results

Participants in the Northern Manhattan Study who had a time-of-flight magnetic resonance angiography were included in this analysis (N=1034). A global arterial Z-score, called the brain arterial remodeling (BAR) score, was obtained by averaging the measured diameters within each individual. Individuals with a BAR score <−2 SDs were considered to have the smallest diameters, individuals with a BAR score >−2 and <2 SDs had average diameters, and individuals with a BAR score >2 SDs had the largest diameters. All vascular events were recorded prospectively after the brain magnetic resonance imaging. Spline curves and incidence rates were used to test our hypothesis. The association of the BAR score with death (P=0.001), vascular death (P=0.02), any vascular event (P=0.05), and myocardial infarction (P=0.10) was U-shaped except for ischemic stroke (P=0.74). Consequently, incidence rates for death, vascular death, myocardial infarction, and any vascular event were higher in individuals with the largest diameters, whereas individuals with the smallest diameters had a higher incidence of death, vascular death, any vascular event, and ischemic stroke compared with individuals with average diameters.

Conclusions

The risk of death, vascular death, and any vascular event increased at both extremes of brain arterial diameters. The pathophysiology linking brain arterial remodeling to systemic vascular events needs further research.

Development of a duplex-derived velocity risk prediction model of disease progression in patients with moderate asymptomatic carotid artery stenosis

OBJECTIVE

Previously, we described risk factors for disease progression in moderate asymptomatic carotid artery stenosis (ASCAS). The aim of the current study was to develop a risk prediction model for disease progression in this group.

METHODS

All patients presenting between January 2005 and May 2012 with moderate (50%-69%) ASCAS, as determined by carotid artery duplex imaging, were included. Cox proportional hazard regression models accounting for measured duplex peak systolic velocity and end-diastolic velocity, and the internal carotid artery (ICA)/common carotid artery (CCA) ratio, with and without previously identified risk factors for progression (age, smoking, dual antiplatelet therapy), were used to develop receiver operating characteristic curves for predicting disease progression.

RESULTS

The study analyzed 282 patients (52% male), aged 71 ± 9 years, with 2.6 ± 0.1 years follow-up and 25% disease progression at a mean time of 2.02 ± 0.18 years. Initial peak systolic velocity, end-diastolic velocity, and the ICA/CCA ratio were all significant independent predictors of progression. Receiver operating characteristic curve analyses suggested that a prediction model based on ICA/CCA ratio alone had optimal prediction efficacy (hazard ratio, 2.01; Harrell's C, 0.74; P < .001). Patients with ICA/CCA >2.5, 3.3, and 3.8 were found to have >10%, >20%, and >30% risk of disease progression over 2 years, respectively. Model sensitivity and specificity for predicting 10% risk of disease progression at 2 years was 80.7% and 64.0%, respectively (positive predictive value, 22.9%; negative predictive value, 96.1%).

CONCLUSIONS

We propose a clinical prediction model for moderate ASCAS disease progression that can be used to risk-stratify patients with >10% risk of progression at 2 years using ICA/CCA ratios. Implementation of this model may be useful for identifying high-risk patients who would benefit from routine carotid disease surveillance follow-up.