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
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
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
Carotid artery intima-media thickness (IMT) is a marker of cardiovascular disease associated with incident stroke. We study whether IMT rate-of-change is associated with stroke.
Materials and Methods
We studied 5028 participants of the Multi-Ethnic Study of Atherosclerosis (MESA) composed of whites, Chinese, Hispanic and African-Americans free of cardiovascular disease. In this MESA IMT progression study, IMT rate-of-change (mm/year) was the difference in right common carotid artery (CCA) far-wall IMT (mm) divided by the interval between two ultrasound examinations (median interval of 32 months). CCA IMT was measured in a region free of plaque. Cardiovascular risk factors and baseline IMT were determined when IMT rate-of-change was measured. Multivariable Cox proportional hazards models generated Hazard risk Ratios (HR) with cardiovascular risk factors, ethnicity and education level/income as predictors.
There were 42 first time strokes seen during a mean follow-up of 3.22 years (median 3.0 years). Average age was 64.2 years, with 48% males. In multivariable models, age (HR: 1.05 per year), systolic blood pressure (HR 1.02 per mmHg), lower HDL cholesterol levels (HR: 0.96 per mg/dL) and IMT rate-of-change (HR 1.23 per 0.05 mm/year; 95% C.L. 1.02, 1.48) were significantly associated with incident stroke. The upper quartile of IMT rate-of-change had an HR of 2.18 (95% C.L.: 1.07, 4.46) compared to the lower three quartiles combined.
Common carotid artery IMT progression is associated with incident stroke in this cohort free of prevalent cardiovascular disease and atrial fibrillation at baseline.
Ultrasonography; Risk Factors; Carotid Arteries; Carotid Intima Media Thickness; stroke
The aim of this study was to determine the relationship between brachial flow-mediated dilation (FMD) and carotid intima-media thickness (IMT) in a large multi-ethnic elderly cohort.
Brachial flow-mediated dilation (FMD) is a physiologic measure and Carotid IMT is an anatomic structural measure of subclinical atherosclerosis. Both brachial FMD and carotid IMT have been associated with cardiovascular risk factors and cardiovascular events. The relationship between brachial FMD and carotid IMT is less clear especially in older adults.
Brachial FMD, carotid IMT and traditional cardiovascular risk factors were measured in 2338 adults, age 72–98 years who were participants in the Cardiovascular Health Study. The relationship between FMD and IMT was assessed both unadjusted and also after adjusting for age, gender, race/ethnicity. BMI, HDL, LDL, systolic and diastolic blood pressure, serum creatinine, current smoking, diabetes mellitus, hormone therapy and prior CVD.
Both brachial FMD and carotid IMT correlated significantly with age, HDL levels, waist/hip ratio, serum cholesterol and number of CV risk factors. Brachial FMD was not associated with CCA IMT in this elderly cohort (Pearson partial correlation coefficient= −0.0252, p=0.222). In the adjusted linear regression model with CCA IMT as the dependent variable, brachial FMD was also not associated with CCA IMT (beta coefficient= −0.006, p=0.470)
Brachial FMD and CCA IMT are not related in population-based older adults. Brachial FMD and CCA IMT may be distinct and independent stages in the complex atherosclerotic process.
Brachial flow-mediated dilation; carotid intima-media thickness; endothelial function; atherosclerosis; elderly
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
It is still not known how patients who are post-transient ischemic attack (TIA) or post-stroke might benefit from prospectively planned comprehensive cardiac rehabilitation (CCR). In this pilot evaluation of a larger ongoing randomized-controlled-trial, we evaluated ultrasound (US) measurements of carotid atherosclerosis in subjects following TIA or mild non-disabling stroke and their relationship with risk factors before and after 6-months of CCR.
Carotid ultrasound (US) measurements of one-dimensional intima-media-thickness (IMT), two-dimensional total-plaque-area (TPA), three-dimensional total-plaque-volume (TPV) and vessel-wall-volume (VWV) were acquired before and after 6-months CCR for 39 subjects who had previously experienced a TIA and provided written informed consent to participate in this randomized controlled trial. We maintained blinding for this ongoing study by representing treatment and control groups as A or B, although we did not identify which of A or B was treatment or control. Carotid IMT, TPA, TPV and VWV were measured before and after CCR as were changes in body mass index (BMI), total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides (TG), systolic blood pressure (SBP) and diastolic blood pressure (DBP).
There were no significant differences in US measurements or risk factors between groups A and B. There was no significant change in carotid ultrasound measurements for group A (IMT, p = .728; TPA, p = .629; TPV, p = .674; VWV, p = .507) or B (IMT, p = .054; TPA, p = .567; TPV, p = .773; VWV, p = .431) at the end of CCR. There were significant but weak-to-moderate correlations between IMT and VWV (r = 0.25, p = .01), IMT and TPV (r = 0.21, p = .01), TPV and TPA (r = 0.60, p < .0001) and VWV and TPV (r = 0.22, p = .02). Subjects with improved TC/HDL ratios showed improved carotid VWV although, this was not statistically significant.
In this preliminary evaluation, there were no significant differences in carotid US measurements in the control or CCR group; a larger sample size and/or longer duration is required to detect significant changes in US or other risk factor measurements.
Carotid ultrasound; Comprehensive cardiac rehabilitation; Transient ischemic attack; Ischemic stroke; Three-dimensional ultrasound; Intima-media thickness; Total plaque area; Total plaque volume; Vessel wall volume
To determine whether cardiovascular risk factors are associated with aortic and carotid intimal-medial thickness (aIMT and cIMT) in adolescents and young adults.
Atherosclerotic lesions begin developing in youth, first in the distal abdominal aorta and later in the carotid arteries. Knowledge of how risk factors relate to aIMT and cIMT may help in the design of early interventions to prevent cardiovascular disease.
Participants were 635 members of the Muscatine Offspring cohort. The mean aIMT and cIMT were measured using an automated reading program.
The means (SDs) of aIMT and cIMT were 0.63 (0.14) mm and 0.49 (0.04) mm, respectively. In adolescents (ages 11 to 17), aIMT was associated with triglycerides, systolic blood pressure (SBP), diastolic blood pressure (DBP), body mass index (BMI), and waist/hip ratio, after adjusting for age, gender, and height. In young adults (ages 18 to 34), aIMT was associated with those same five risk factors, plus HDL-cholesterol and pulse pressure. In adolescents, cIMT was associated with SBP, pulse pressure, heart rate, BMI, and waist/hip ratio. In young adults, cIMT was associated total cholesterol, LDL-cholesterol, triglycerides, SBP, .DBP, BMI, waist/hip ratio, and HbA1C. In both age groups, aIMT and cIMT were significantly correlated with the PDAY coronary artery risk score.
Both aIMT and cIMT are associated with cardiovascular risk factors. Using aIMT in adolescents gives information beyond that obtained from cIMT alone. Measurement of aIMT and cIMT may help identify those at risk for premature cardiovascular disease.
Atherosclerosis; Ultrasound; Preclinical disease; Abdominal aorta; IMT
Objective: Epicardial adipose tissue thickness (EATT) is suggested as a new cardiometabolic risk factor. Carotid intima-media thickness (IMT) is a potential indicator of subclinical atherosclerosis in patients with metabolic syndrome (MS). We investigated the association of EATT with carotid IMT and cardiac functional changes in obese adolescents with MS.
Methods: One hundred thirty-eight obese adolescents and 63 lean subjects were enrolled in the study. The obese subjects were divided into two subgroups based on the presence or absence of MS (MS group and non-MS group). All subjects underwent transthoracic echocardiographic examination for determination of left ventricular (LV) function, LV mass index (LVMI), and myocardial performance index (MPI). EATT and carotid IMT were also measured during echocardiography.
Results: The average LVMI measurements were higher in both MS and non-MS obese patients in comparison with the lean children. The MS group had significantly higher LVMI measurements than the non-MS and lean groups (88.5±23.0, 67.5±24.8 g/m2, and 62.4±18.2 g/m2, respectively; p<0.01). Carotid IMT was higher in both the MS and non-MS obese patients in comparison with the lean group. The MS group had significantly higher carotid IMT measurements than the non-MS and lean groups (0.91±0.23, 0.78±0.18, and 0.52±0.08 mm, respectively; p<0.01). The EATT was also increased significantly in patients with MS compared to lean adolescents (7.42±1.55 vs. 4.28±0.79mm; p=0.001). EATT was positively correlated with body mass index-SDS, waist circumference, fasting glucose, insulin, homeostasis model assessment-insulin resistance, triglyceride levels, LV thickness, LVMI, and MPI in the MS obese group. EATT was the only independent predictor of carotid IMT in the multivariate analysis (β= 0.69, p<0.001).
Conclusion: The findings of the present study demonstrate a close relationship of EATT with carotid IMT and early cardiac dysfunction in obese adolescents with MS. Assessment of EATT and carotid IMT in routine echocardiographic examinations is suggested as a feasible and reliable method for the evaluation of obesity with MS and its related cardiovascular risks in children and adolescents.
Conflict of interest:None declared.
metabolic syndrome; epicardial adipose; tissue; carotid intima-media thickness
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.
Trial registry no:
Leukocyte subtype counts; Carotid intima-media thickness; Diabetic macrovascular complication; Type 2 diabetes
Previous research has demonstrated an increase in carotid intima–media thickness (cIMT) in HIV-infected individuals compared to controls. However, the reason for this increased level of subclinical vascular disease is unknown.
To identify HIV-related risk factors for increased cIMT.
We evaluated the relationship between HIV-related characteristics (including markers of HIV disease severity and use of antiretroviral therapy) and cIMT measurements in the internal/bulb and common carotid regions among 538 HIV-infected participants from the Study of Fat Redistribution and Metabolic Change in HIV Infection (FRAM). We used Bayesian model averaging to estimate the posterior probability of candidate HIV and non-HIV-related risk factors being true predictors of increased cIMT. Variables with a posterior probability of more than 50% were used to develop a selected regression model for each of the anatomic regions.
For common cIMT, the Bayesian model selection process identified age, African-American race, and systolic and diastolic blood pressure with probability more than 95%, HDL cholesterol with probability 85% and Hispanic ethnicity with probability 51%. Among the HIV-related factors included in the analysis, only tenofovir use was selected (51% probability). In the selected model, duration of tenofovir use was associated with lower common cIMT (−0.0094 mm/year of use; 95% confidence interval: −0.0177 to −0.0010). For internal cIMT, no HIV-related risk factors were above the 50% posterior probability threshold.
We observed an inverse association between duration of tenofovir use and common carotid cIMT. Whether this association is causal or due to confounding by indication needs further investigation.
atherosclerosis; carotid intima–media thickness; HIV; tenofovir
This study investigated the long-term effects of intensive diabetic treatment on the progression of atherosclerosis, measured as common carotid artery intima-media thickness (IMT).
RESEARCH DESIGN AND METHODS
A total of 1,116 participants (52% men) in the Epidemiology of Diabetes Interventions and Complications (EDIC) trial, a long-term follow-up of the Diabetes Control and Complications Trial (DCCT), had carotid IMT measurements at EDIC years 1, 6, and 12. Mean age was 46 years, with diabetes duration of 24.5 years at EDIC year 12. Differences in IMT progression between DCCT intensive and conventional treatment groups were examined, controlling for clinical characteristics, IMT reader, and imaging device.
Common carotid IMT progression from EDIC years 1 to 6 was 0.019 mm less in intensive than in conventional (P < 0.0001), and from years 1 to 12 was 0.014 mm less (P = 0.048); but change from years 6 to 12 was similar (intensive − conventional = 0.005 mm, P = 0.379). Mean A1C levels during DCCT and DCCT/EDIC were strongly associated with progression of IMT, explaining most of the differences in IMT progression between DCCT treatment groups. Albuminuria, older age, male sex, smoking, and higher systolic blood pressure were significant predictors of IMT progression.
Intensive treatment slowed IMT progression for 6 years after the end of DCCT but did not affect IMT progression thereafter (6–12 years). A beneficial effect of prior intensive treatment was still evident 13 years after DCCT ended. These differences were attenuated but not negated after adjusting for blood pressure. These results support the early initiation and continued maintenance of intensive diabetes management in type 1 diabetes to retard atherosclerosis.
Background and Purpose
Atherosclerosis is a complex disorder with hereditary and environmental causes. Carotid artery intima-media wall thickness (IMT) is a useful measure of atherosclerosis. The objective of this study was to determine the association between carotid IMT and functional promoter variants of stromelysin-1 (MMP3: −1612 5A>6A), interleukin-6 (IL6: −174G>C), and hepatic lipase (HL: −480C>T) genes.
B-mode carotid ultrasound was performed among 87 subjects (mean age, 70 ± 12 years; 55% women; 60% Caribbean-Hispanic, 25% black, and 13% white) from the Northern Manhattan Prospective Cohort Study. Carotid IMT was calculated as a composite measure (mean of the maximum IMT in the bifurcation, the common carotid artery, and the internal carotid artery).
For all polymorphisms, genotype distribution was not significantly different from Hardy-Weinberg equilibrium. The frequencies of the rare alleles were as follows: MMP3 −1612 5A>6A, 0.31 (95% CI, 0.25 to 0.39); IL6 −174 G>C, 0.20 (95% CI, 0.13 to 0.25); and HL −480 C>T, 0.45 (95% CI, 0.35 to 0.50). Carotid IMT in the sample was 0.78±0.18 mm. Subjects with the MMP3 genotype 6A6A had 8% greater mean carotid IMT than the other MMP3 genotypes combined (0.95±0.17 versus 0.87±0.15 mm; P=0.04). Subjects with the IL6 genotype GG had 11% greater IMT (0.85±0.17 versus 0.76±0.16 mm; P=0.03), and those with the HL genotype CC had 13% greater IMT (0.87±20 versus 0.76±0.18 mm; P=0.02) than the other genotypes combined. Adjustment for other risk factors did not change these associations.
Carotid IMT is higher among subjects homozygous for functional variants in genes related to matrix deposition (MMP3 −16126A), inflammation (IL6 −174G), and lipid metabolism (HL −480C). These associations were independent of race-ethnicity and some environmental exposures. Further studies are needed to confirm these genotype-phenotype associations.
genetics; interleukin-6; intima-media thickness; lipase; stromelysin 1; ultrasonography
Recent studies have confirmed inflammatory factors and metabolic syndrome (MetS) as important cardiovascular disease (CVD) risk factors. Recently measurement of carotid intima-media thickness (IMT) has been used for evaluation of early atherosclerosis. This study was designed to assess the correlation between IMT with some inflammatory biomarkers, ghrelin and adiponectin in people with and without MetS in a cohort sample in Isfahan province.
Among participants of Isfahan Cohort Study (ICS) by random sampling, 88 participants were selected and divided into case (with MetS) and control (without MetS) groups. A questionnaire including demographic data and CVD risk factors was completed for all of the participants. Physical examination and blood pressure, height, weight and waist circumference measurements were done for all subjects. Vascular echocardiography was done for evaluation of IMT of each carotid artery of both sides. Interlukin-6 (IL-6), interlukin-10 (IL-10), highly sensitive C-reactive protein (hs-CRP), ghrelin and adiponectin levels were measured using ELIZA method. Data were entered in SPSS15 software and analyzed by t-test, chi square, Pearson correlation and linear regression analyze.
The mean waist circumference, BMI, systolic blood pressure, diastolic blood pressure, hs-CRP and IMT of left carotid artery were significantly higher in participants with Mets. There was significant correlation between left carotid IMT and IL-6 level in all patients (P = 0.03). After adjustment for age and sex, significant relationship in groups with MetS was only reported between the left IMT and IL-6 (P = 0.02). There was no relation between IMT and other inflammatory markers in subjects with and without MetS.
Significant correlation between IL-6 and IMT was reported in patients with MetS. While no significant correlation between IL-10, adiponectin and ghrelin with IMT was observed in metabolic syndrome group.
Intima-media thickness (IMT); Carotid artery; hs-CRP; Ghrelin; Adiponectin IL-6; IL-10
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
Non-alcoholic fatty liver disease (NAFLD), an emerging public health problem, may be a highly atherogenic condition. But the relationship between fatty liver diseases and carotid atherosclerosis in small-animal is incompletely understood. The purpose of the present study was to evaluate carotid intima-media thickness (IMT) in NAFLD rats using high-frequency ultrasonic diagnostic equipment, and to ascertain if the degree of hepatic pathological changes was associated with carotid IMT.
Liver injury was induced by a high-fat diet for 8, 12 and 16 weeks, separately, in fifty four SD rats (27 treated, 27 controls). Liver echogenicity and IMT of the carotid and aorta were evaluated and compared to histological findings of them. In comparison with the rats in the control group, fatty liver disease in rats was characterized by homogeneous and diffusely increased echogenicity (bright liver), an increased anteroposterior diameter of the liver and serum biochemical changes. Hepatic histological analyses demonstrated indications of simple steatosis in rats induced by an 8-week high-fat diet, and a high-fat diet for 12 weeks and 16 weeks could induce steatohepatitis (NASH) in rats. The 12- and 16-week groups had a significantly higher inflammation scores than those of the control groups. IMT values for the carotid and aorta were remarkably increased in the NASH groups compared with the control groups (P < 0.05). The end-diastolic velocity and systolic peak velocity of the carotid and aorta in the NASH groups were significantly smaller than those in the control group. A significant correlation between the IMT of the carotid with hepatic inflammation score (r2 = 0.598, P = 0.001) and the systolic peak velocity of the carotid (r2 = −0.342, P = 0.041) were shown in NAFLD rats.
We demonstrated that ultrasound imaging in the diagnosis of fatty liver disease and early atherosclerosis in rats is feasible and efficient, and that carotid IMT increased significantly in NASH rats but not in simple steatotic rats. A significant correlation between the IMT of the carotid artery with hepatic inflammation score were shown in NAFLD rats. This method for non-invasive diagnosis is especially relevant in the research of the pathogenesis and therapy of NAFLD and atherosclerosis using rodent models.
Non-alcoholic fatty liver disease; Atherosclerosis; Ultrasound; Intima-media thickness; Rat
The Epidemiology of Diabetes Interventions and Complications (EDIC) is a multicenter longitudinal observational study of the Diabetes Control and Complications Trial (DCCT) cohort. One of the major objectives of EDIC is to study the development and progression of atherosclerotic cardiovascular disease in type 1 diabetes. In this study, we evaluated the role of cardiovascular risk factors and antecedent therapy in the DCCT on carotid intima-media wall thickness (IMT) in type 1 diabetes. At ~18 months after the end of the DCCT, high-resolution B-mode ultrasonography was used to assess the carotid arteries of 1,325 patients with type 1 diabetes, 19–51 years of age, with duration of diabetes ranging from 6.3 to 26.1 years. An age- and sex-matched nondiabetic population (n = 153) was studied with the same protocol. The ultrasound protocol was carried out in 28 EDIC clinics by centrally trained and certified sonographers using one of three scanning systems. Determination of IMT from videotaped images was performed by a single reader at the Central Ultrasound Reading Unit. Univariate associations with greater IMT were strongest for older age and longer diabetes duration, greater waist-to-hip ratio (men only), higher blood pressure, higher LDL cholesterol, and smoking. The DCCT therapy group (intensive versus conventional) and HbA1c, measured at the time of the ultrasound or the mean HbA1c during the DCCT, were not significantly related to IMT. Multivariate analyses suggest that age, height, smoking, and BMI were the major predictors of common carotid IMT, whereas age, smoking, and LDL cholesterol predicted internal carotid IMT. There were significant differences between the IMT values of the internal carotid artery in the EDIC male cohort and similarly aged male nondiabetic control subjects. There were no significant differences between the IMT values in the EDIC female cohort and similarly aged female nondiabetic control subjects. At this point in the planned 10-year follow-up of the DCCT cohort, neither intensive therapy nor HbA1c level appears to influence the early signs of atherosclerosis. Traditional risk factors, including age, smoking, and LDL cholesterol, were related to IMT. As the cohort is only now entering the age interval during which rapid progression and clinical expression of atherosclerosis are expected, further follow-up will help to determine the role of hyperglycemia, and its interaction with other risk factors, on the development of atherosclerosis.
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
To estimate the heritability of carotid intima-media thickness (IMT), a surrogate marker for atherosclerosis, independent of traditional coronary risk factors.
Methods and Results
We performed a classical twin study of carotid IMT using 98 middle-aged male twin pairs, 58 monozygotic (MZ) and 40 dizygotic (DZ) pairs, from the Vietnam Era Twin Registry. All twins were free of overt cardiovascular disease. Carotid IMT was measured by ultrasound. Bivariate and multivariate analyses were used to determine the association between traditional cardiovascular risk factors and carotid IMT. Intraclass correlation coefficients and genetic modeling techniques were used to determine the relative contributions of genes and environment to the variation in carotid IMT. In our sample, the mean of the maximum carotid IMT was 0.75 ± 0.11. Age, systolic blood pressure and HDL were significantly associated with carotid IMT. The intraclass correlation coefficient for carotid IMT was larger in MZ (0.66; 95% confidence interval [CI], 0.62–0.69) than in DZ twins (0.37; 95% CI, 0.29–0.44), and the unadjusted heritability was 0.69 (95% CI, 0.54–0.79). After adjusting for traditional coronary risk factors, the heritability of carotid IMT was slightly reduced but still of considerable magnitude (0.59; 95% CI, 0.39–0.73).
Genetic factors have a substantial influence on the variation of carotid IMT. Most of this genetic effect occurs through pathways independent of traditional coronary risk factors.
heritability; carotid intima-media thickness; twin study; atherosclerosis
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.
Impact of multiple cardiovascular (CV) risk factors on the intima-media thickness (IMT) of femoral and carotid artery segments measured simultaneously has not been studied in asymptomatic adults. This study examined the impact of multiple CV risk factors on the IMT in asymptomatic adults.
Femoral and carotid IMT were measured by B-mode ultrasonography in 1080 asymptomatic subjects (aged 24–43 years) of the Bogalusa Heart Study.
In multivariate analyses, systolic blood pressure, age, male, total cholesterol/HDL cholesterol ratio and smoking were common independent predictor variables for the femoral and carotid IMT. Systolic blood pressure followed by age were the major determinant risk factors for the IMT of all arterial segments except carotid bulb for which age was the major predictor. The independent variables listed explained 11% of the variability in femoral IMT, 28% in common carotid, 18% in carotid bulb, 10% in internal carotid and 27% in composite carotid segments. Mean IMT increased with increasing number of risk factors in all arterial segments; p for trend = 0.003 for femoral and 0.001 for all carotid segments.
The observed deleterious trend of increasing IMT of the femoral and different segments of the carotid artery with increasing number of CV risk factors provide evidence of silent systemic atherosclerosis in asymptomatic young adults. These findings underscore the importance of multiple for risk factors profiling in early life. Studies of the femoral and carotid IMT may be helpful along with measurements of risk factors for evaluation of asymptomatic atherosclerotic disease.
femoral and carotid artery; intima-media thickness; risk factors; ultrasonography; arterial disease
Objectives. Cardiovascular disease remains the major cause of death in SLE. We assessed the degree to which cardiovascular risk factors (CVRFs) and disease activity were associated with 2-year changes in measures of subclinical atherosclerosis.
Methods. One hundred and eighty-seven SLE patients participating in a placebo-controlled trial of atorvastatin underwent multi-detector CT [for coronary artery calcium (CAC)] and carotid duplex [for carotid intima–media thickness (IMT) and carotid plaque] twice, 2 years apart. During the 2 years, patients were assessed every 3 months for CVRF. Both groups were combined for analysis, as atorvastatin did not differ from placebo in preventing progression of coronary calcium. We examined the correlation between these clinical measures and progression of CAC, IMT and plaque during the follow-up period.
Results. In an analysis adjusting for age, gender and ethnicity, CAC progression was positively associated with total serum cholesterol measured over the 2-year period (P = 0.04) and smoking (P = 0.003). Carotid IMT progression was associated with systolic BP (P = 0.003), high-sensitivity CRP (hsCRP) (P = 0.013) and white blood cell (WBC) count (P = 0.029). Carotid plaque progression, defined as patients without carotid plaque at baseline with subsequent development of plaque at follow-up, was associated with systolic BP (P = 0.003), WBC count (P = 0.02), physician's global assessment (P = 0.05), blood lymphocyte count (P = 0.048), urine protein (P = 0.017) and duration of SLE (P = 0.019).
Conclusion. Our data did not provide evidence of an association between measures of SLE disease activity (SLEDAI, anti-dsDNA, anti-phospholipid and treatment) and progression of subclinical atherosclerosis. Age and hypertension were associated with the progression of carotid IMT and plaque. Age, smoking and cholesterol were associated with progression of CAC.
Systemic lupus erythematosus; Helical computed tomography; Coronary artery calcium; Carotid intima–media thickness; Carotid plaque; Inflammation; Atherosclerosis; Carotid duplex; Coronary artery disease; Statins
Endothelial progenitor cells (EPCs) are involved in the endothelium repair. Low circulating EPC levels are predictive of cardiovascular events in HIV-negative subjects. The impact of HIV infection on EPCs, and the role of EPCs in HIV-associated cardiovascular disease, is not known. We hypothesized that circulating EPCs would be inversely associated with carotid artery intima-media thickness (c-IMT) changes in HIV-infected subjects.
EPCs (CD34+/KDR+, CD133+/KDR+ and CD34+/CD133+/KDR+) were defined retrospectively by flow cytometry in cryopreserved peripheral blood mononuclear cells collected longitudinally from 66 chronic HIV-infected subjects and cross-sectionally from 50 at-risk HIV-negative subjects. The HIV-infected subjects participated in the Study of the Consequences of the Protease Inhibitor Era (SCOPE) cohort, were receiving antiretroviral therapy (59/66) and had two sequential measurements of c-IMT 1 year apart. Two distinct groups of HIV-infected subjects were identified a priori: rapid c-IMT progressors (subjects with rapid c-IMT progression, n=13, Δc-IMT>0.2 mm) and slow c-IMT progressors (subjects with slow or no c-IMT progression, n=53, Δc-IMT<0.2 mm).
Although cryopreservation reduced sensitivity of detection, EPC frequency in HIV-infected subjects was still significantly higher compared to at-risk HIV-negative subjects (CD34+/KDR+; P=0.01) and correlated positively with CD4+ T-cell count (CD34+/KDR+, r=0.27; P=0.03). No association was found between the change of EPC frequencies over time (ΔEPC) and Δc-IMT or between EPC frequencies and c-IMT or Δc-IMT.
The lack of an association between EPCs and c-IMT in our cohort does not support HIV-associated reductions in EPC frequency as a cause of accelerated atherosclerosis.
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
To determine whether within-visit blood pressure (BP) variability based on three measurements over minutes is associated with increased carotid intima-media thickness (IMT) and plaque in a general population.
A cross-sectional survey was performed in 2007, and a total of 1222 Beijing community residents aged 50–79 years belonging to part of the Chinese Multi-Provincial Cohort Study (CMCS) were recruited in this study. BP was measured three times at 5-minute intervals during a single visit, and the maximum absolute difference (MAD) between any two readings of three measurements was used to indicate within-visit BP variability. Carotid IMT and plaque scanned by B-mode ultrasound were identified as the surrogate end points in the intermediate stage of atherosclerosis.
After adjustment for established cardiovascular risk factors, the odds ratio (OR) (95% confidence interval (CI)) for increased carotid IMT and internal carotid plaque associated with the highest within-visit diastolic BP (DBP) variability (MAD > mean + standard deviation (SD)) compared with participants in the lowest within-visit DBP variability (MAD ≤ mean −SD) was 4.92 (1.48–16.42) and 6.07 (1.31–28.10), respectively, in the normotensives (P = 0.01; P = 0.02). The OR (95% CI) for internal carotid plaque associated with the highest within-visit systolic BP (SBP) variability (MAD >mean +SD) compared with participants in the lowest within-visit SBP variability (MAD ≤ mean −SD) was 3.54 (1.26–10.00) in the hypertensives on antihypertensive therapy (P = 0.02).
Within-visit DBP variability was associated with increased carotid IMT and internal carotid plaque in the normotensive population, and within-visit SBP variability was associated with internal carotid plaque in hypertensive patients undergoing antihypertensive therapy.