Carotid intima-media thickness (IMT) is a marker of cardiovascular disease derived from ultrasound images of the carotid artery. In most outcome studies, human readers identify and trace the key IMT interfaces. We evaluate an alternate approach using automated edge detection.
We study a subset of 5640 participants with an average age 61.7 years (48% men) of the Multi-Ethnic Study of Atherosclerosis composed of whites, Chinese, Hispanic and African-Americans that are part of the MESA IMT progression study. Manual tracing IMT (mt_IMT) and edge-detected IMT (ed_IMT) measurements of the far wall of the common carotid artery (CCA) served as outcome variables for multivariable linear regression models using Framingham cardiovascular risk factors and ethnicity as independent predictors.
Measurements of mt_IMT was obtainable in 99.9% (5633/5640) and of ed_IMT in 98.9% (5579/5640) of individuals. Average ed_IMT was 0.19 mm larger than mt_IMT. Inter-reader systematic differences (bias) in IMT measurements were apparent for mt_IMT but not ed_IMT. Based on complete data on 5538 individuals, associations of IMT with risk factors were stronger (p < 0.0001) for mt_IMT (model r2: 19.5%) than ed_IMT (model r2: 18.5%).
We conclude that this edge-detection process generates IMT values equivalent to manually traced ones since it preserves key associations with cardiovascular risk factors. It also decreases inter-reader bias, potentially making it applicable for use in cardiovascular risk assessment.
Ultrasonography; Risk Factors; Carotid Arteries; Carotid Intima Media Thickness
Common carotid artery intima-media thickness (IMT), a measure of subclinical cardiovascular disease, changes during the cardiac cycle. The magnitude of this effect and its implications have not been well studied.
Methods and Results
Far-wall IMT measurements of the right common carotid artery were measured at end diastole and peak systole in 5633 individuals from the Multi-Ethnic Study of Atherosclerosis (MESA). Multivariable regression models were generated with end-diastolic IMT, peak-systolic IMT, and change in IMT during the cardiac cycle as dependent variables and traditional cardiovascular risk factors as independent variables. The average age of our population was 61.9 (45 to 84) years. Average change in carotid IMT during the cardiac cycle was 0.041 mm (95% confidence interval: 0.039 to 0.042 mm), with a mean IMT of 0.68 mm. End-diastolic IMT and peak-systolic IMT were similarly associated with risk factors. In a fully adjusted model, change in carotid IMT during the cardiac cycle was associated with ethnicity and pulse pressure (P=0.001) and not age, sex, or other risk factors. Chinese and Hispanics had less of a change in IMT than did non-Hispanic whites. With peak-systolic IMT reference values used as normative data, 31.3% more individuals were classified as being in the upper quartile of IMT and at high risk for cardiovascular disease than would be expected when IMT is measured at end diastole.
Measurable differences in IMT are seen during the cardiac cycle. This affects the interpretation of IMT measurements used for cardiovascular risk assessment, given published normative data with IMT measured at peak systole.
Clinical Trial Registration
URL: www.ClinicalTrials.gov. Unique identifier: NCT00063440. (J Am Heart Assoc. 2012;1:e001420 doi: 10.1161/JAHA.112.001420.)
atherosclerosis; blood pressure; carotid arteries; diastole; epidemiology; risk factors; systole; ultrasonics
Common carotid artery inter-adventitial diameter (IAD) and intima-media thickness (IMT) are measurable by ultrasound. IAD may be associated with left ventricular mass (LV mass) while IMT is a marker of subclinical atherosclerosis. It is not clear if IAD is associated with LV mass after accounting for IMT and traditional cardiovascular risk factors.
IAD and IMT were measured on participants of the Multi-Ethnic Study of Atherosclerosis (MESA) IMT progression study. A total of 5641 of the originally enrolled 6814 MESA participants were studied. LV mass was measured by magnetic resonance imaging. Multivariable linear regression was used with IAD as the outcome and adjustment for risk factors, as well as IMT and LV mass.
Traditional cardiovascular risk factors, height, weight and ethnicity were significantly associated with IAD. After adjustment for risk factors, a one mm difference in IMT was associated with a 1.802 mm (95% CI: 1.553, 2.051) higher mean IAD. A one gm difference in LV mass was associated with a 0.006 mm (95% CI: 0.005, 0.007) higher mean IAD. LV mass was independently associated with IAD after adjusting for cardiovascular risk factors and IMT. These associations were slightly different for men and women.
Inter-adventitial diameters are associated with left ventricular mass after adjusting for cardiovascular risk factors and IMT. IAD might serve as a surrogate for left ventricular mass and have predictive value for cardiovascular outcomes.
carotid arteries; ultrasonics; hypertrophy; magnetic resonance imaging; remodeling; risk factors; left ventricle
Carotid intima-media thickness (IMT) is a sub-clinical marker of atherosclerosis and a strong predictor of stroke. Pericardial fat (PF), the fat depot around the heart, has been associated with several atherosclerosis risk factors. We sought to examine the association between carotid IMT and PF, and to examine whether such an association is independent from common atherosclerosis risk factors including measures of overall adiposity.
Unadjusted and multivariable adjusted linear regression analysis was used to examine associations between common (CCA-IMT) and internal (ICA-IMT) carotid IMT with PF in a random sample of 996 participants from the Multi-Ethnic Study of Atherosclerosis (MESA) who underwent carotid ultrasound and chest CT at baseline examination.
A significant positive correlation was observed between PF and CCA-IMT (r =0.27, P<0.0001) and ICA-IMT (r =0.17, P<0.0001). In an unadjusted sex-specific linear regression analysis, there was a significant association between PF (1-SD difference) and CCA-IMT (mm) in both women (β coefficient (95% CI): 0.06 (0.04, 0.08), P<0.0001) and men (0.03 (0.01, 0.05), P<0.0002), an association that persisted after further adjusting for age and ethnicity (0.02 (+0.00, 0.04), P=0.0120 for women, and 0.02 (+0.00, 0.03), P=0.0208 for men). However, after additional adjustment for atherosclerosis risk factors and either BMI or waist circumference, these relations were no longer significant in either sex. In similar analyses, PF was significantly associated with ICA-IMT in both men (0.11 (0.06, 0.15), P<0.0001) and women (0.08 (0.02, 0.13), P=041). These relations were no longer significant in women in multivariable adjusted models, but persisted in men in all models except after adjusting for age, ethnicity and waist circumference.
In the general population PF is associated with carotid IMT, an association that possibly not independent from markers of overall adiposity or common atherosclerosis risk factors.
Common carotid artery (CCA) intima-media thickness (cIMT), a measure of atherosclerosis, varies between peak-systole (PS) and end-diastole (ED). This difference might affect cardiovascular risk assessment.
Materials and methods
IMT measurements of the right and left CCA were synchronized with an electrocardiogram: R-wave for ED and T-wave for PS. IMT was measured in 2930 members of the Framingham Offspring Study. Multivariable regression models were generated with ED-IMT, PS-IMT and change in IMT as dependent variables and Framingham risk factors as independent variables. ED-IMT estimates were compared to the upper quartile of IMT based on normative data obtained at PS.
The average age of our population was 57.9 years. Average difference in IMT during the cardiac cycle was 0.037 mm (95% CI: 0.035–0.038 mm). ED-IMT and PS-IMT had similar associations with Framingham risk factors (total R2= 0.292 versus 0.275) and were significantly associated with all risk factors. In a fully adjusted multivariable model, a thinner IMT at peak-systole was associated with pulse pressure (p < 0.0001), LDL-cholesterol (p = 0.0064), age (p = 0.046), and no other risk factors. Performing ED-IMT measurements while using upper quartile PS-IMT normative data lead to inappropriately increasing by 42.1% the number of individuals in the fourth IMT quartile (high cardiovascular risk category).
The difference in IMT between peak-systole and end-diastole is associated with pulse pressure, LDL-cholesterol, and age. In our study, mean IMT difference during the cardiac cycle lead to an overestimation by 42.1% of individuals at high risk for cardiovascular disease.
Ultrasonics; Risk Factors; Carotid Arteries; Blood Pressure; systole; diastole
Coronary artery calcium (CAC) and carotid intima-media thickness (IMT) are noninvasive measures of atherosclerosis that consensus panels have recommended as possible additions to risk factor assessment for predicting the probability of cardiovascular disease (CVD) occurrence.
To assess whether maximum carotid IMT or CAC (Agatston Score) is the better predictor of incident CVD.
Design, Setting, Patients
Prospective cohort study of 45–84 year-olds initially free of CVD (n = 6,698) in four ethnic groups, with standardized carotid IMT and CAC measures at baseline, in six field centers of the Multi-Ethnic Study of Atherosclerosis (MESA).
Main Outcome Measure(s)
Incident CVD events (coronary heart disease, stroke, and fatal CVD) over a maximum of 5.3 years of follow-up.
There were 222 CVD events during follow-up. CAC was associated more strongly than carotid IMT with risk of incident CVD. After adjustment for each other and traditional CVD risk factors, the hazard of CVD increased 2.1-fold (95% CI 1.8–2.5) for each standard deviation greater level of log-transformed CAC, versus 1.3-fold (95% CI 1.1–1.4) for each standard deviation greater maximum IMT. For coronary heart disease, the hazard ratios per standard deviation increment were 2.5-fold (95% CI 2.1–3.1) for CAC and 1.2-fold (95% CI 1.0–1.4) for IMT. An ROC analysis also suggested that CAC predicted incident CVD better than IMT did.
Although whether and how to clinically use bio-imaging tests of subclinical atherosclerosis remains a topic of debate, this study found that CAC predicts subsequent CVD events better than does carotid IMT.
Occupation has been linked to cardiovascular disease (CVD) incidence and mortality, but few studies have investigated occupation in relation to early atherosclerotic disease. This study examined associations between various occupational characteristics and carotid artery intima-media thickness (IMT) in a multi-ethnic sample.
The Multi-Ethnic Study of Atherosclerosis (MESA) recruited 6814 adults aged 45e84 years and free of clinical CVD (response rate 60%, 51% female). Questionnaire data were used to determine occupational group (managerial/professional, sales/office, service, blue-collar), psychosocial job characteristics (ie, job demands, job control) and other sociodemographic information.
Common carotid artery (CCA)-IMT was greater for blue-collar jobs than for management/professional jobs (mean difference=0.012 mm, p=0.049) after adjustment for age, sex, race, place of birth (US or foreign born) and CVD risk factors. Compared to management/professional jobs, internal carotid artery (ICA)-IMT was greater for sales/office, service and blue-collar jobs (mean difference=0.071 mm, p<0.001; 0.057 mm, p=0.009; and 0.110 mm, p<0.001, respectively) after adjustment for age, sex, race and place of birth. The difference between blue-collar jobs and management/professional jobs remained significant after additional adjustment for CVD risk factors, income and education (mean difference=0.048 mm, p=0.045). Higher levels of control at work were associated with thinner CCA-IMT (mean difference=‒0.009 mm, p=0.016, adjusted for age, sex, race and place of birth) but not with ICA-IMT. Job demands had no significant association with IMT.
Blue-collar jobs and low levels of job control were associated with the development of subclinical atherosclerosis.
External common carotid artery (CCA) diameter and intima-media thickness (IMT) are independently associated with incident stroke and other cardiovascular events. Arterial geometry such as large IMT and large diameter may reflect vulnerable plaques and so impact stroke risk. Finally, arterial changes that exist bilaterally may increase stroke risk.
We studied middle-aged men and women (n=7276) from a prospective observational study who had right (R) and left (L) CCA IMT and external diameters measured via B-mode ultrasound (1987–89) in order to categorize CCA geometry. Using side- and gender-specific IMT and diameter medians, we categorized each measurement as large (≥ median) vs. not large (< median) and defined four geometries: both IMT and diameter were large, only one parameter was large, or neither was large (reference group). Participants were followed for first time stroke through December 31, 1999. We used proportional hazards models to assess associations between right and left CCA geometries with new stroke. We also calculated positive and negative likelihood ratios (+LR and -LR) for CCA bilateral phenotypes as a measure of diagnostic accuracy.
Presence of both large CCA IMT and large diameter on one side was associated with strong stroke risk even after risk factor adjustment (men: RCCA hazard ratio [HR]=3.7 95% confidence interval [CI]=1.9-7.4; LCCA HR=2.4 95% CI=1.4-4.4; women: RCCA HR=4.0 95% CI=1.5-10.5; LCCA HR=5.7 95% CI=1.7-19.0). Presence of both large IMT and large diameter bilaterally was the strongest predictor of stroke identifying 64% of women and 44% of men who developed strokes. This phenotype showed potential for predicting stroke among individuals (women: +LR=3.1, 95% CI=2.6-3.8; men: +LR=2.3, 95% CI=1.8-2.8).
Bilateral carotid artery geometries may be useful for stroke risk prediction.
Stroke; Atherosclerosis; Carotid arteries; Ultrasound; Intima-media thickness; Arterial diameter; Arterial geometry; Bilateral; Prospective study
The goal of this study was to compare internal carotid artery (ICA) intima-media thickness (IMT) with common carotid artery (CCA) IMT as global markers of cardiovascular disease (CVD).
Cross-sectional measurements of the mean CCA IMT and maximum ICA IMT were made on ultrasound images acquired from the Framingham Offspring cohort (n = 3316; mean age, 58 years; 52.7% women). Linear regression models were used to study the associations of the Framingham risk factors with CCA and ICA IMT. Multivariate logistic regression models and receiver operating characteristic (ROC) curve analysis were used to compare the associations of prevalent CVD with CCA and ICA IMT and determine sensitivity and specificity.
The association between age and the mean CCA IMT corresponded to an increase of 0.007 mm/y; the increase was 0.037 mm/y for the ICA IMT. Framingham risk factors accounted for 28.6% and 27.5% of the variability in the CCA and ICA IMT, respectively. Age and gender contributed 23.5% to the variability of the CCA IMT and 22.5% to that of the ICA IMT, with the next most important factor being systolic blood pressure (1.9%) for the CCA IMT and smoking (1.6%) for the ICA IMT. The CCA IMT and ICA IMT were statistically significant predictors of prevalent CVD, with the ICA IMT having a larger area under the ROC curve (0.756 versus 0.695).
Associations of risk factors with CCA and ICA IMT are slightly different, and both are independently associated with prevalent CVD. Their value for predicting incident cardiovascular events needs to be compared in outcome studies.
atherosclerosis; carotid artery; disease prevalence; intima-media thickness; risk factors
Background and Purpose
We propose to study possible differences in the associations between risk factors for cardiovascular disease (myocardial infarction and stroke) and Carotid Intima-Media thickness (IMT) measurements made at three different levels of the carotid bifurcation. Methods: Cross-sectional study of a cohort of Whites and African Americans of both genders with mean age 45 years. Traditional cardiovascular risk factors were determined in cohort members. Carotid IMT was measured from high-resolution B-mode ultrasound images at three levels: the common carotid artery (CCA), the carotid artery bulb (Bulb) and the internal carotid artery (ICA). Associations with risk factors were evaluated by multivariate linear regression analyses.
Of 3258 who underwent carotid IMT measurements, CCA, Bulb, and ICA IMT were measured at all three separate levels in 3023 (92.7%). A large proportion of the variability of CCA IMT was explained by cardiovascular risk factors (26.8%) but less so for the Bulb (11.2%) and ICA (8.0%). Carotid IMT was consistently associated with age, LDL-cholesterol, smoking and hypertension in all segments. Associations with fasting glucose and diastolic blood pressure were stronger for CCA than for the other segments. Hypertension, diabetes and current smoking had qualitatively stronger associations with Bulb IMT, and LDL cholesterol with ICA IMT. Conclusion: In our cohort of relatively young white and African-American men and women, a greater proportion of the variability in common carotid IMT can be explained by traditional cardiovascular risk factors than for the carotid artery bulb and internal carotid arteries.
Carotid Intimal Medial Thickness; Risk Factors; Carotid Ultrasound
Higher plasma total homocysteine (tHcy) is an established risk factor for cardiovascular disease. The relation between tHcy and carotid artery intima-media thickness (IMT) at the internal carotid artery (ICA)/bulb-IMT and common carotid artery (CCA)-IMT has not been systematically examined. Since the ICA/bulb segment is more prone to plaque formation than the CCA segment, differential associations with tHcy at these sites might suggest mechanisms of tHcy action.
We examined the cross-sectional segment-specific relations of tHcy to ICA/bulb-IMT and CCA-IMT in 2,499 participants from the Framingham Offspring Study, free of cardiovascular disease.
In multivariable linear regression analysis, ICA/bulb-IMT was significantly higher in the fourth tHcy quartile category compared to the other quartile categories, in both the age- and sex-adjusted and in the multivariable-adjusted model (P for trend <0.0001 and <0.01, respectively). We observed a significant age by tHcy interaction for ICA/bulb-IMT (P=0.03) and therefore stratified the analyses by median age (58 years). There was a significant positive trend between tHcy and ICA/bulb-IMT in individuals 58 years of age or older (P-trend <0.01), but not in the younger individuals (P-trend=0.24). For CCA-IMT, no significant trends were observed in any of the analyses.
The segment-specific association between elevated tHcy levels and ICA/bulb-IMT suggests an association between tHcy and plaque formation.
carotid artery; intima-media thickness; homocysteine; atherosclerosis; Framingham Offspring Study
Background and Purpose
Both carotid intima-media thickness (IMT) and obesity are independent determinants of stroke and cardiovascular disease. The prevalence of obesity is higher in Hispanics. The genetic basis of IMT and obesity has not been well-characterized in Caribbean Hispanics. The purpose of this study was to examine the genetic and environmental contributions to IMT and obesity in this population.
The data included 440 subjects from 77 Caribbean Hispanic families. Mean IMT and maximum IMT were measured in the internal carotid artery, common carotid artery, and carotid bifurcation. The total IMT was calculated as the mean value of IMT at all segments. Obesity phenotypes included body mass index (BMI), waist circumference, waist-to-hip ratio (WHR), and skin-fold thickness. Variance component methods were used to estimate age-adjusted and sex-adjusted heritability. Bivariate analyses were conducted to test for genetic and environmental correlations between IMT and obesity.
Heritabilities for IMT ranged from 9% to 40%, with the highest for total maximum IMT and lowest for internal carotid artery maximum IMT. Heritabilities for BMI, waist circumference, WHR, and skin-fold thickness were 44%, 47%, 5%, and 36%, respectively. There were significant genetic, but not environmental, correlations between IMT and BMI, waist circumference, and skin-fold thickness. There were no genetic or environmental correlations between IMT and WHR.
We found a substantial genetic contribution to IMT, BMI, waist circumference, and skin-fold thickness. Obesity and IMT may share common genetic factors. Future gene mapping studies are warranted to identify genes predisposing to IMT and obesity in this population.
carotid arteries; genetics; obesity; stroke
Although intima-media thickness (IMT) was increased in several inflammatory diseases, studies investigating whether the inflammatory processes lead to macrovascular alteration with increased IMT in complex regional pain syndrome (CRPS) lack.
Using ultrasound (high-resolution B-mode), we compared bilaterally the IMT of the common carotid artery (CCA-IMT), the radial artery (RA-IMT), the brachial artery (BRA-IMT) and the quotient QRA/CCA, in CRPS type I (n=17), peripheral nerve injury (PNI, n=17) and pain-free controls (PFC, n=22, matched to CRPS by gender, age and traditional cardiovascular risk factors). Statistics: Spearman’s correlation, paired t-test, ANOVA (p<0.05).
Compared to PFC, RA-IMT were significantly increased in both patient groups bilaterally (mean±standard deviation, CRPS affected side vs. PFC dominant side: 0.32±0.08 mm vs. 0.19±0.08 mm, p<0.001; PNI affected side vs. PFC dominant side: 0.27±0.09 mm vs. 0.19±0.08 mm, p< 0.05; CRPS non-affected side vs. PFC non-dominant side: 0.30±0.10 mm vs. 0.19±0.09 mm, p<0.001; PNI non-affected side vs. PFC non-dominant side: 0.25±0.10 mm vs. 0.19±0.09 mm, p<0.05) and QRA/CCA (CRPS affected-side vs. PFC dominant side: 0.49±0.12 vs. 0.30±0.11, p<0.001; PNI affected side vs. PFC dominant side: 0.41±0.10 vs. 0.30±0.11, p<0.05; CRPS non-affected side vs. PFC non-dominant side: 0.43±0.19 vs. 0.30±0.13, p<0.001; PNI non-affected side vs. PFC non-dominant side: 0.39±0.14 vs. 0.30±0.13, p<0.05), and BRA-IMT - only on the affected side in CRPS (CRPS: 0.42±0.06 mm vs. PFC: 0.35±0.08 mm; p<0.05). In CRPS, QRA/CCA was significantly higher on the affected side compared to PNI (p<0.05). However, only CRPS displayed within-group side-to-side differences with a significantly increased RA-IMT and QRA/CCA on the affected side (p<0.05). The CCA-IMT was comparable between all groups and sides.
The increased IMT of peripheral arteries in CRPS suggests ongoing inflammatory process. Until now, only endothelial dysfunction has been reported. The presented morphological macrovascular alterations might explain the treatment resistance of some CRPS patients.
Complex regional pain syndrome; Macrovascular changes; Intima-media thickness; Inflammatory alterations
Systematic differences between readers or equipment in imaging studies are not uncommon; failure to account for such differences when using Carotid Ultrasonography may introduce bias into associations between carotid intima media thickness (cIMT) and outcomes. We demonstrate the impact of this source of systematic measurement error (SME) using data on 5,521 participants from the Multi-Ethnic Study of Atherosclerosis (MESA) and 661 participants from the Study of Fat Redistribution and Metabolic Change in HIV Infection (FRAM). Participants were between 37 and 78 years old. Two outcomes were considered: (1) the effect of HIV infection on cIMT (between study) and (2) the association of cIMT with cardiovascular events (within study). All estimates were adjusted for demographics (age, gender, and ethnicity) and for traditional cardiovascular disease risk factors (smoking, blood pressure, diabetes and cholesterol). When comparing the FRAM and MESA cohorts to estimate the association of HIV infection on common cIMT, accounting for machine and reader variability (between study variability) reduced the difference associated with HIV infection from +0.080 mm (95% Confidence Interval (CI):0.065–0.095) to +0.037 mm (95% CI:0.003 to 0.072) while internal cIMT declined from +0.254 mm (95% CI:0.205–0.303) to +0.192 mm (95% CI:0.076–0.308). Attenuation of the association between cIMT and cardiovascular endpoints occurred when within study reader variability was not accounted for. The effect of SME due to use of multiple readers or machines is most important when comparisons are made between two different study populations. Within-cohort measurement error dilutes the association with events.
Carotid intima media thickness; Measurement error; Bias; Carotid ultrasonography
Background and purpose
Adiponectin is an insulin-sensitizing plasma protein expressed in adipose tissue and suggested to play a role in atherosclerosis and cardiovascular disease. Data are lacking on the relationship between adiponectin and carotid intima-media thickness (IMT) in ethnically heterogeneous populations. We examined the relationship between adiponectin and IMT, a marker of atherosclerosis, in a multi-ethnic cohort study of stroke risk factors.
Participants were from the Northern Manhattan Study (N=1522, mean age 66±9 years, 60% female, 20% black, 18% white, 60% Hispanic). Adiponectin was measured from baseline plasma samples and IMT was assessed by high-resolution B-mode carotid ultrasound. Regression models were used to examine the association between adiponectin, assessed continuously and in quartiles, and IMT, controlling for demographics and vascular risk factors.
The mean adiponectin level was 10.3±5.2 μg/ml (median=9.2, range=2.3-53.3), and the mean IMT was 0.91±0.08 mm. Adiponectin was inversely associated with IMT, even after controlling for demographics and vascular risk factors. Individuals in the first quartile of adiponectin had mean IMT that was on average 0.02 mm greater than those in the top quartile. The relationship between adiponectin and IMT appeared to be stronger among those with diabetes.
Our findings suggest that low adiponectin is associated with increased IMT in a multi-ethnic cohort and support a protective role for adiponectin in atherosclerosis.
Adiponectin; carotid artery; intima-media thickness; atherosclerosis; epidemiology
Intima-media thickness (IMT) of the carotid arteries is known to have a positive correlation with the risk of cardiovascular disease. This study was designed to identify risk factors affecting the progression of carotid IMT in patients with type 2 diabetes mellitus (T2DM).
Patients with newly diagnosed T2DM with carotid IMT measurements were enrolled, and their clinical data and carotid IMT results at baseline and 2 years later were compared.
Of the 171 patients, 67.2% of males and 50.8% of females had abnormal baseline IMT of the left common carotid artery. At baseline, systolic blood pressure, body mass index and smoking in male participants, and fasting plasma glucose and glycated hemoglobin levels in females were significantly higher in patients with abnormal IMT than in those with normal IMT. Low density lipoprotein cholesterol (LDL-C) levels in males and high density lipoprotein cholesterol (HDL-C) levels in females at the 2-year follow-up were significantly different between the nonprogression and the progression groups. Reduction of the United Kingdom Prospective Diabetes Study (UKPDS) 10-year coronary heart disease (CHD) risk score after 2 years was generally higher in the nonprogression group than the progression group.
LDL-C levels in males and HDL-C levels in females at the 2-year follow-up were significantly different between participants with and without progression of carotid IMT. Furthermore, a reduction in the UKPDS 10-year CHD risk score appeared to delay the advancement of atherosclerosis. Therefore, the importance of establishing the therapeutic goal of lipid profiles should be emphasized to prevent the progression of carotid IMT in newly diagnosed T2DM patients.
Atherosclerosis; Carotid artery intima-media thickness; Diabetes mellitus type 2; Risk factors
Intima-media thickness (IMT) of the common and internal carotid arteries is an established surrogate for atherosclerosis and predicts risk of stroke and myocardial infarction. Often IMT is measured as the average of these two arteries, yet they are believed to result from separate biological mechanisms. The aim of this study was to conduct a family-based genome-wide association study (GWAS) for IMT to identify polymorphisms influencing IMT and to determine if distinct carotid artery segments are influenced by different genetic components.
Methods and Results
IMT for the common and internal carotid arteries was determined through B-mode ultrasound in 772 Mexican Americans from the San Antonio Family Heart Study. A GWAS utilizing 931,219 single nucleotide polymorphisms (SNPs) was undertaken with six internal and common carotid artery IMT phenotypes utilizing an additive measured genotype model. The most robust association detected was for two SNPs (rs16983261, rs6113474, p=1.60e−7) in complete linkage disequilibrium on chromosome 20p11 for the internal carotid artery near wall, next to the gene PAX1. We also replicated previously reported GWAS regions on chromosomes 19q13 and 7q22. We found no overlapping associations between internal and common carotid artery phenotypes at p<5.0e0−6. The genetic correlation between the two carotid IMT arterial segments was 0.51.
This study represents the first large scale GWAS of carotid IMT in a non-European population and identified several novel loci. We do not detect any shared GWAS signals between common and internal carotid arterial segments but the moderate genetic correlation implies both common and unique genetic components.
intima-media thickness; carotid artery; GWAS; Hispanics
Carotid intima-media thickness (cIMT) is an independent predictor of cardiovascular risk. Furthermore, ethnicity and gender-specific normative data are required to assess cIMT, which are not available for Andean-Hispanics. In addition, data regarding correlates of subclinical atherosclerosis in ethnic population are needed.
We studied 1448 adults enrolled in a population-based study in Peru. cIMT and carotid plaque were measured with high-resolution ultrasonography. A healthy reference sample (n=472) with no cardiovascular disease, normal weight and normal metabolic parameters was selected to establish normative cIMT values. Correlates of abnormal cIMT and carotid plaque were assessed in the entire population.
In the reference sample, 95th-percentile cIMT values were both age and gender-dependent. In stepwise regression, selected predictors of increasing cIMT were: older age, impaired fasting glucose, diabetes mellitus, higher systolic blood pressure, higher LDL-cholesterol, smoking and male gender. Predictors of carotid plaque included older age, male gender, higher systolic blood pressure, lower diastolic blood pressure and higher LDL-cholesterol. HDL-cholesterol and C-reactive protein were not associated with cIMT or carotid plaque. The lack of association with HDL-cholesterol was confirmed using high performance liquid chromatography.
We present ethnic-specific cutoffs for abnormal cIMT applicable to Andean-Hispanics and correlates of subclinical atherosclerosis in this population. Pending longitudinal studies, our data supports several risk associations seen in other populations and can be used to identify Andean-Hispanics at increased risk for atherosclerotic cardiovascular disease. The lack of association between HDL-C and cIMT or carotid plaque in this population requires further investigation.
carotid intima-media thickness; Andean-Hispanics; definitions; cardiovascular disease; Latin America
Background and Purpose
Small vessel disease contributes to the pathophysiology of stroke, and retinal microvascular signs have been linked to risk of stroke. We examined the relationship of retinal signs with incident stroke in a multi-ethnic cohort.
The Multi-Ethnic Study of Atherosclerosis (MESA) is a prospective cohort study that enrolled participants without clinical cardiovascular diseases from six United States communities between 2000–02. Of the participants, 4,849 (71.2%) had fundus photography performed in 2002–04. Retinopathy and retinal vessel caliber were assessed from retinal images. Stroke risk factors including high-sensitivity C-reactive protein (hsCRP), carotid artery intima-media thickness (IMT) and coronary artery calcium (CAC) were measured using standardized protocols. Incident stroke was confirmed from medical record review and death certificates.
After 6 years of follow-up, there were 62 incident strokes. Narrower retinal arteriolar caliber was associated with increased risk of stroke after adjusting for conventional cardiovascular risk factors (adjusted incidence rate ratio [IRR] 2.83, 95% confidence interval [CI] 1.34–5.95, p=0.006; adjusted hazard ratio [HR] 3.01, 95% CI 1.29–6.99, p=0.011). Retinopathy in persons without diabetes was associated with increased risk of stroke (adjusted IRR 2.96, 95% CI 1.50–5.84, p=0.002; adjusted HR 3.07, 95%CI 1.17–8.09, p=0.023). These associations remained significant after adjusting for hsCRP, carotid IMT or CAC.
Narrower retinal arteriolar caliber and retinopathy in non-diabetic persons were associated with increased risk of stroke in this relatively healthy multi-ethnic cohort independent of traditional risk factors and measures of atherosclerosis. The association between narrower retinal arteriolar caliber and stroke warrants further investigation.
Stroke; Retinal microvascular signs; Retinopathy; Retinal vessel caliber
Cardiovascular disease (CVD) is an increasing cause of morbidity and mortality in HIV-infected patients. However, it is controversial whether HIV infection contributes to accelerated atherosclerosis independent of traditional CVD risk factors.
Cross-sectional study of HIV-infected and control subjects without pre-existing CVD from the study of Fat Redistribution and Metabolic Change in HIV Infection (FRAM) and the Multi-Ethnic Study of Atherosclerosis (MESA). Pre-clinical atherosclerosis was assessed by carotid intima-medial thickness (IMT) measurements in the internal/bulb and common regions in HIV-infected and control subjects after adjusting for traditional CVD risk factors.
For internal carotid, mean IMT was 1.17±0.50mm for HIV-infected participants and 1.06±0.58mm for controls (p<0.0001). After multivariable adjustment for demographic characteristics, the mean difference of HIV-infected vs. controls was +0.188mm (95%CI 0.113-0.263, p<0.0001). Further adjustment for traditional CVD risk factors modestly attenuated the HIV association (+0.148mm, 95%CI 0.072-0.224, p=0.0001). For the common carotid, HIV infection was independently associated with greater IMT (+0.033mm, 95%CI 0.010, 0.056, p=0.005). The association of HIV infection with IMT was similar to that of smoking which was also associated with greater IMT (internal +0.173mm, common +0.020mm).
Even after adjustment for traditional CVD risk factors, HIV infection was accompanied by more extensive atherosclerosis measured by IMT. The stronger association of HIV infection with IMT in the internal/bulb region compared to the common carotid may explain previous discrepancies in the literature. The association of HIV infection with IMT was similar to that of traditional CVD risk factors, such as smoking.
HIV; carotid IMT; smoking; cholesterol; diabetes; atherosclerosis
Increased carotid artery intima-media thickness (IMT) is a non-invasive marker of systemic arterial disease. Increased IMT has been associated with atherosclerosis, abnormal arterial mechanics, myocardial infarction, and stroke. Given evidence of a relationship between cardiovascular health and attention-executive-psychomotor functioning, the purpose of this study was to examine IMT in relation to neuropsychological test performance in patients with a variety of cardiovascular diagnoses.
One hundred and nine participants, ages 55 to 85, underwent neuropsychological assessment and B-mode ultrasound of the left common carotid artery. IMT was calculated using an automated algorithm based on a validated edge-detection technique. The relationship between IMT and measures of language, memory, visual-spatial abilities and attention-executive-psychomotor functioning was modeled using hierarchical linear regression analyses adjusted for age, education, sex, cardiovascular risk, current systolic blood pressure, and history of coronary artery disease (CAD).
Increased IMT was associated with significantly lower performance in the attention-executive-psychomotor domain (IMT beta = −0.26, p < .01), independent of age, education, sex, cardiovascular risk, current systolic blood pressure, and CAD (F(10,100) = 3.61, p < .001). IMT was not significantly related to language, memory, or visual-spatial abilities.
Our findings suggest that, in patients with cardiovascular disease, IMT may be associated with the integrity of frontal subcortical networks responsible for attention-executive-psychomotor performance. Future studies are needed to clarify the mechanisms by which IMT affects cognition and examine potential interactions between increased IMT and other measures of cardiovascular health such as blood pressure variability, cardiac systolic performance, and systemic perfusion.
Cognition; Cardiovascular Diseases; Carotid Arteries; Atherosclerosis; IMT; B-mode Ultrasound
An increased leukocyte count is an independent risk factor for cardiovascular events, but the association between leukocyte subtype counts and carotid atherosclerosis in patients with diabetes has not been determined. We therefore investigated the correlation between leukocyte subtype counts and intima-media thickness of the common carotid artery (CCA-IMT) in subjects with type 2 diabetes.
This cross-sectional study involved 484 in-patients with type 2 diabetes (282 males and 202 females), who were hospitalized for glycemic control and underwent carotid ultrasonography at Kumamoto University Hospital between 2005 and 2011. Mean and maximum CCA-IMT was measured by high-resolution B-mode ultrasonography.
Univariate analyses revealed that mean CCA-IMT was positively correlated with age, systolic blood pressure, brachial-ankle pulse wave velocity (PWV), urinary albumin excretion and duration of diabetes, but was negatively correlated with diastolic blood pressure and fasting plasma glucose. Maximum CCA-IMT was positively and negatively correlated with the same factors as mean CCA-IMT except for fasting plasma glucose. Mean CCA-IMT was positively correlated with total leukocyte (r = 0.124, p = 0.007), monocyte (r = 0.373, p < 0.001), neutrophil (r = 0.139, p = 0.002) and eosinophil (r = 0.107, p = 0.019) counts. Maximum CCA-IMT was positively correlated with total leukocyte (r = 0.154, p < 0.001), monocyte (r = 0.398, p < 0.001), neutrophil (r = 0.152, p < 0.001) and basophil counts (r = 0.102, p = 0.027). Multiple regression analyses showed that monocyte count, age and PWV were significant and independent factors associated with mean CCA-IMT (adjusted R2 = 0.239, p < 0.001), and that monocyte count, age and urinary albumin excretion were significant and independent factors associated with maximum CCA-IMT (adjusted R2 = 0.277, p < 0.001).
Monocyte counts were positively correlated with both mean CCA-IMT and maximum CCA-IMT in patients with type 2 diabetes. Monocyte count may be a useful predictor of macrovascular complications in patients with type 2 diabetes.
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Leukocyte subtype counts; Carotid intima-media thickness; Diabetic macrovascular complication; Type 2 diabetes
Background and Purpose
Carotid atherosclerosis has been associated with increased risk of stroke, and poorer cognitive performance in older adults. The relation of carotid atherosclerosis to cognitive impairment and MRI indices of ischemia and aging in midlife is less clear.
We studied 1,975 Framingham Offspring Study participants free of stroke and dementia with available carotid ultrasound, brain MRI and neuropsychological testing. We related common and internal carotid artery intima-media thickness (ICA-IMT and CCA-IMT respectively) and internal carotid stenosis (CAS) to large white matter hyperintensity (>1-SD above age-specific mean; LWMH), total brain volume (TCBV), hippocampal volume, silent cerebral infarcts (SCI) and neuropsychological measures of verbal memory, executive function and non-verbal memory measures.
We observed that ICA-IMT, but not CCA-IMT, was associated with higher prevalence of SCI (OR 1.21, 95% CI 1.03–1.43, p<0.05), LWMH (OR 1.19, 95% CI 1.03–1.38, p<0.05), lower TCBV (−0.05 per SD, p<0.05) and poorer performance in verbal memory (−0.06 per SD; p<0.05) and non-verbal memory measures (−0.08 per SD; p<0.01), but not with hippocampal volume. CAS ≥25% was associated with a higher prevalence of LWMH (adjusted OR 1.77, 95% CI 1.25–2.53) and lower TCBV (−0.11 per SD, p=0.042) but not with SCI or hippocampal volume. CAS ≥50% was associated with higher prevalence of SCI (OR 2.53, 95% CI 1.17 – 5.44), LWMH (OR 2.35, 95% CI 1.08–5.13) and poorer performance on executive function (−0.39 per SD; p<0.05) but not with TCBV or hippocampal volume.
Carotid atherosclerosis markers were associated with MRI indices of brain ischemia and aging and with cognitive impairment in a community-based sample of middle-aged adults. Our data suggest that ICA-IMT may be a better marker for cognitive impairment than CCA-IMT.
Carotid atherosclerosis; brain MRI; cognitive performance
Polycystic ovary syndrome (PCOS) is a common reproductive endocrine disorder associated with cardiovascular disease (CVD) risk factors and metabolic disturbances and a genetically heterogeneous disease. Intima-media thickness (IMT) is an indicator of atherosclerosis. This study aimed to determine the relation between IMT and PCOS in women.
This cross-sectional study was performed on 44 PCOS patients and 44 healthy women. Data collection included lipid profiles, blood pressure, waist circumference, body mass index (BMI), and common and internal IMT of carotid artery which were measured in studied subjects. IMT was measured by a radiologist using a linear 12 MHz ultrasound probe (LOGIC S6, GE) in carotid setting.
IMT of common carotid artery (56.8 ± 7.6 in cases versus 49.8 ± 7.3 in controls), internal carotid artery (56.9 ± 6.03 in cases versus 49.6 ± 6.9 in controls), and both common and internal carotid artery (56.6 ± 6.7 in cases versus 49.7 ± 6.9 in controls) were significantly higher in PCOS patients than healthy women (P < 0.001).
In summary, results demonstrated that carotid artery thickness as a risk for premature atherosclerosis in patients with PCOS is higher than healthy subjects. And hence care and monitoring of PCOS women with these risk factors sounds to be important and necessary.
Carotid intima-media thickness; carotid artery thickness; intima-media thickness; oligomenorrehea; polycystic ovarian syndrome
Objective: Sudden death has been reported in asymptomatic obese adults and the mechanism is unclear. In recent years, obesity has shown a dramatic increase in children and this enhances the risk factors for the development of cardiovascular disease. The aim of this study was to investigate whether there is repolarization abnormality and any potential risk factor such as increase in intima-media thickness (IMT) of carotid artery for corrected QT (QTc) prolongation among obese children.
Methods: A total of 60 obese children, 30 of which had features of metabolic syndrome (MS), and 23 age-matched controls were included in the study. QTc interval was calculated at rest. The IMT of both common carotid arteries (CCA) was measured. The relationship between QTc, IMT of right and left CCA and insulin sensitivity indices were evaluated in the study group.
Results: The QTc interval of the children with simple exogenous obesity (SEO) were longer than in the controls (p=0.024). The IMT of both carotid arteries of the obese girls and boys with and without MS were higher than the controls (p=<0.001). The QTc was significantly affected by the parameters pertaining to the right carotid artery IMT, to chronologic age and HDL-C.
Conclusion: Since obesity may cause subclinical atherosclerotic disease regardless of sex, obese children must be followed closely for early cardiovascular problems.
Conflict of interest:None declared.
obesity; QTc; carotid artery intima-media thickness