Vascular morbidity and mortality due to cardiovascular disease (CVD) are high after ischemic stroke at a young age. Data on carotid intima-media thickness (cIMT) as marker of atherosclerosis are scarce for young stroke populations. In this prospective case–control study, we examined cIMT, the burden of vascular risk factors (RF) and their associations among young and middle-aged ischemic stroke patients and controls. We aimed to detect clinical and sub-clinical arterial disease.
This study was conducted in 150 patients aged 15–60 years and 84 controls free of CVD. We related RF to ultrasonographic B-mode cIMT-measurements obtained from 12 standardized multiangle measurements in the common carotid artery (CCA), carotid bifurcation (BIF) and internal carotid artery (ICA).
RF burden was higher among patients than among controls (p < 0.001). In multivariate analyses of all 234 participants, increased cIMT was associated with age in each carotid segment. Incident stroke was associated with increased ICA-IMT. ICA-IMT increase was associated with a family history of CVD among patients aged 15–44 years, and with RF at mid-age. The overall cIMT difference between patients and controls was 12% for CCA, 17% for BIF and 29% for ICA. Further, increased CCA-IMT was associated with male sex and hypertension. Increased BIF-IMT was associated with dyslipidemia, coronary heart disease and smoking. Increased ICA-IMT was associated with dyslipidemia and stroke.
Ischemic stroke is associated with increased ICA-IMT, related to a family history of CVD among patients aged <45 years, and to increasing RF burden with increasing age. Preventive strategies and aggressive RF treatment are indicated to avoid future cardiovascular events.
NOR-SYS is registered in ClinicalTrials.gov (NCT01597453).
Young stroke; Ischemic stroke; Risk factors; Carotid intima-media thickness; Atherosclerosis; Ultrasound
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
Conflicting information exists regarding the association between hsCRP and the progression of early stages of atherosclerosis. The purpose of the study was to investigate the association of high sensitiviy c-reactive protein (hsCRP) along with major cardiovascular (CV) risk factors on early carotid atherosclerosis progression in a large, population-based cohort study.
The study cohort included 839 young adults (aged 24 to 43 years, 70% white, 42% men) enrolled in Bogalusa Heart Study, who in 2001-2002 attended baseline examination with measurements of CV risk factors. Progression of carotid artery intima-media thickness (IMT) was assessed during a mean follow-up of 2.4 years.
Carotid artery IMT progression rates were as follows: composite carotid artery = 9.2 ± 52 μm/y, common carotid artery = 0.0 ± 51 μm/y, carotid bulb = 8.8 ± 103 μm/y, and internal carotid artery = 18.9 ± 81 μm/y. Elevated baseline hsCRP, reflecting an inflammatory state, showed independent association with composite carotid artery IMT progression. Increased age, systolic blood pressure, fasting glucose, LDL cholesterol, and current smoking were other risk associates of carotid artery IMT progression in young adults, indicating an underlying burden on the CV system by multiple risk factors.
In this population-based study, we observed independent categorical association of increased hsCRP with carotid artery IMT progression in young adults. This study underlines the importance of assesssing hsCRP levels along with smoking and traditional CV risk factor profiles in asymptomatic young adults.
Carotid artery intima-media thickness progression; cardiovascular risk; c-reactive protein; epidemiology; young adults
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
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
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
Race-specific data for the association between coronary artery calcification (CAC) and carotid intimal medial thickness (IMT) are limited. We sought to compare black-white specific associations of these two measures.
We conducted a population-based study of 379 randomly-selected men aged 40–49 years (84 black and 295 white) from Allegheny County, US (2004–2006). Agatston CAC score was evaluated by electron-beam tomography and carotid IMT was evaluated by ultrasonography.
Compared to white men, black men had similar prevalence of CAC (p=0.56) and higher total carotid IMT (p<0.001). In black and white men, CAC score had significant positive correlations with total carotid IMT (r=0.47 & r=0.24 respectively, p<0.001 for both) as well as the IMT for the common carotid artery (CCA), internal carotid artery and carotid bulb. The associations of CAC with total and CCA IMT were significantly stronger in black (beta=0.07 & beta=0.05 respectively) than white men (beta=0.03 & beta=0.01 respectively) after adjustment for traditional coronary risk factors (p=0.046 & p=0.036 respectively).
In black and white middle-aged men, CAC score had significant positive correlations with total and segmental carotid IMT. CAC was more predictive of total and CCA IMT in black than white men independent of coronary risk factors.
Epidemiology; atherosclerosis; coronary calcification; carotid intimal medial thickness; Caucasian; black
To examine whether 10-year change in occupational mobility is related to carotid artery intima-media thickness (IMT) 5 years later.
Data were obtained from 2350 participants in the Coronary Artery Risk Development in Young Adults (CARDIA) Study. Occupational standing was measured at the Year 5 and 15 CARDIA follow-up exams when participants were 30.2+3.6 and 40.2+3.6 years of age, respectively. IMT (common (CCA), internal (ICA), and bulb) was measured at Year 20. Occupational mobility was defined as the change in occupational standing between Years 5 and 15 using two semi-continuous variables. Analyses controlled for demographics, CARDIA center, employment status, parents’ medical history, own medical history, Year 5 Framingham risk score, physiological risk factors and health behaviors averaged across the follow-up, and sonography reader.
Occupational mobility was unrelated to IMT save for an unexpected association of downward mobility with less CCA-IMT (β= −.04, p=.04). However, associations differed depending on initial standing (Year 5) and sex. For those with lower initial standings upward mobility was associated with less CCA-IMT (β= −.07, p=.003) and downward mobility with greater CCA-IMT and bulb-ICA-IMT (β= .14, p=.01 and β= .14, p=.03, respectively); for those with higher standings, upward mobility was associated with greater CCA-IMT (β= .15, p=.008) but downward mobility was unrelated to either IMT measure (ps>.20). Sex-specific analyses revealed associations of upward mobility with less CCA-IMT and bulb-ICA-IMT among men only (ps<.02).
Occupational mobility may have implications for future cardiovascular health. Effects may differ depending on initial occupational standing and sex.
CARDIA; IMT; occupational mobility; occupational social class; socioeconomic status
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
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
Reliability of the most commonly used duplex ultrasound (DUS) velocity thresholds for internal carotid artery (ICA) stenosis has been questioned since these thresholds were developed using less precise methods to grade stenosis severity based on angiography. In this study, maximum percent diameter carotid bulb ICA stenosis (European Carotid Surgery Trial [ECST] method) was objectively measured using high resolution B-mode DUS validated with computed tomography angiography (CTA) and used to determine optimum velocity thresholds for ≥50% and ≥80% bulb internal carotid artery stenosis (ICA).
B-mode DUS and CTA images of 74 bulb ICA stenoses were compared to validate accuracy of the DUS measurements. In 337 mild, moderate, and severe bulb ICA stenoses (n = 232 patients), the minimal residual lumen and the maximum outer bulb/proximal ICA diameter were determined on longitudinal and transverse images. This in contrast to the North American Symptomatic Carotid Endarterectomy Trial (NASCET) method using normal distal ICA lumen diameter as the denominator. Severe calcified carotid segments and patients with contralateral occlusion were excluded. In each study, the highest peak systolic (PSV) and end-diastolic (EDV) velocities as well as ICA/common carotid artery (CCA) ratio were recorded. Using receiver operating characteristic (ROC) analysis, the optimum threshold for each hemodynamic parameter was determined to predict ≥50% (n = 281) and ≥80% (n = 62) bulb ICA stenosis.
Patients mean age was 74 ± 8 years; 49% females. Clinical risk factors for atherosclerosis included coronary artery disease (40%), diabetes mellitus (32%), hypertension (70%), smoking (34%), and hypercholesterolemia (49%). Thirty-three percent of carotid lesions (n = 110) presented with ischemic cerebrovascular symptoms and 67% (n = 227) were asymptomatic. There was an excellent agreement between B-mode DUS and CTA (r = 0.9, P = .002). The inter/intraobserver agreement (κ) for B-mode imaging measurements were 0.8 and 0.9, respectively, and for CTA measurements 0.8 and 0.9, respectively. When both PSV of ≥155 cm/s and ICA/CCA ratio of ≥2 were combined for the detection of ≥50% bulb ICA stenosis, a positive predictive value (PPV) of 97% and an accuracy of 82% were obtained. For a ≥80% bulb ICA stenosis, an EDV of ≥140 cm/s, a PSV of ≥370 cm/s and an ICA/CCA ratio of ≥6 had acceptable probability values.
Compared with established velocity thresholds commonly applied in practice, a substantially higher PSV (155 vs 125 cm/s) was more accurate for detecting ≥50% bulb/ICA stenosis. In combination, a PSV of ≥155 cm/s and an ICA/CCA ratio of ≥2 have excellent predictive value for this stenosis category. For ≥80% bulb ICA stenosis (NASCET 60% stenosis), an EDV of 140 cm/s, a PSV of ≥370 cm/s, and an ICA/CCA ratio of ≥6 are equally reliable and do not indicate any major change from the established criteria. Current DUS ≥50% bulb ICA stenosis criteria appear to overestimate carotid bifurcation disease and may predispose patients with asymptomatic carotid disease to untoward costly diagnostic imaging and intervention.
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
Molecular and cell biology studies have demonstrated an association between bone and arterial wall disease, but the significance of a population-level association is less clear and potentially confounded by inability to account for shared risk factors.
To test population-level associations between atherosclerosis types and bone integrity.
Main Outcome Measures
Volumetric trabecular lumbar bone mineral density (vBMD), ankle-brachial index (ABI), intima-media thickness of the common carotid (CCA-IMT) and internal carotid (ICA-IMT) arteries, and carotid plaque echogenicity.
Design, Setting and Participants
A random subset of participants from the Multi-Ethnic Study of Atherosclerosis (MESA) assessed between 2002 and 2005.
904 post-menopausal female (62.4 years; 62% non-white; 12% ABI<1; 17% CCA-IMT>1mm; 33% ICA-IMT>1mm) and 929 male (61.4 years; 58% non-white; 6% ABI<1; 25% CCA-IMT>1mm; 40% ICA-IMT>1mm) were included. In serial, sex-specific regression models adjusting for age, ethnicity, body mass index, dyslipidemia, hypertension, smoking, alcohol consumption, diabetes, homocysteine, interleukin-6, sex hormones, and renal function, lower vBMD was associated with lower ABI in men (p for trend <0.01) and greater ICA-IMT in men (p for trend <0.02). CCA-IMT was not associated with vBMD in men or women. Carotid plaque echogenicity was independently associated with lower vBMD in both men (trend p=0.01) and women (trend p<0.04). In all models, adjustment did not materially affect results.
Lower vBMD is independently associated with structural and functional measures of atherosclerosis in men and with more advanced and calcified carotid atherosclerotic plaques in both sexes.
Dyslipidemia is common among adolescents with type 2 diabetes (T2D).
To assess whether the lipoprotein ratios LDL/HDL or TG/HDL (low density lipoprotein cholesterol/ high density lipoprotein cholesterol or triglycerides/HDL) or non-HDL cholesterol are more useful than the traditional lipid panel to predict increased arterial thickness in adolescents and young adults T2D. .
We evaluated 244 T2D adolescents and young adults in a cross sectional study (mean age 18 years, 56% African American, 65% female). Demographics, anthropometrics, and laboratory data were collected. Arterial thickness was assessed using carotid intima media thickness (IMT). Bivariate correlations and general linear models were used to determine the independent contributions of the various lipid parameters to carotid IMT.
Bivariate correlations revealed LDL/HDL ratio was the strongest predictor carotid IMT (p<0.02). After adjustment for potential covariates LDL/HDL was no longer significant. HDL cholesterol was the only lipid to independently (negatively) contribute to carotid IMT. Other risk factors that were independently associated with carotid IMT included age, race, sex and body mass index z score and hemoglobin A1C. Together these cardiovascular risk factors explained less than 20% of the variance in carotid IMT.
HDL cholesterol is the only lipid to independently associate with carotid IMT. Lipoprotein ratios and non-HDL did not provide additional information. The low variance in carotid IMT explained by traditional risk factors suggests nontraditional risk factors may be important to assess to better understand the contributors to early stage atherosclerosis in adolescents and young adults with T2D.
type 2 diabetes; lipids; lipoproteins; adolescents; pediatrics; carotid intima media thickness; vascular disease
Epidemiologic studies of the association between alcohol consumption and carotid artery structure have reported conflicting results. We investigated the association between alcohol consumption and carotid atherosclerosis by evaluating the effects of alcohol intake on carotid artery enlargement.
The study population consisted of 4302 community-dwelling Koreans (1577 men and 2725 women) aged 50 years and over. All the subjects had participated in the baseline survey of the Dong-gu Study conducted between 2007 and 2008. Daily alcohol consumption was determined by the number and frequency of alcoholic beverages consumed. We measured common carotid artery intima-media thickness (CCA-IMT), common carotid and bulb IMT (CB-IMT), carotid plaques, and the diameter of the common carotid artery (CCA-diameter) using high-resolution B-mode ultrasonography. We used analysis of covariance and multiple logistic regressions to determine the relationship between alcohol consumption and carotid artery parameters.
CCA-IMT and CB-IMT were negatively correlated with alcohol consumption after controlling for cardiovascular risk factors in men (p for linear trend = 0.009 and = 0.038, respectively). The multivariate-adjusted odds ratio (OR) for carotid plaques was significantly higher in men who consumed >40.0 g/d (OR = 1.81, 95% CI = 1.13-2.91), although a significant positive correlation was observed between alcohol consumption and carotid plaques (p for linear trend = 0.027). Neither carotid IMT nor carotid plaques were correlated with alcohol intake in women. Alcohol intake was positively correlated with CCA-diameter adjusted for carotid IMT and plaques in the multivariate-adjusted model in both sexes (p for linear trend <0.001 for men and 0.020 for women).
The results of our study indicate that alcohol consumption is inversely related to carotid IMT and positively related to carotid plaques in men, but not women. However, alcohol intake is positively associated with CCA-diameter in both men and women. Additional large population-based prospective studies are needed to confirm the effects of alcohol consumption on carotid artery structure.
Background and Purpose
Higher plasma concentrations of the endogenous nitric oxides synthase (NOS) inhibitor asymmetric dimethylarginine (ADMA) are associated with increased risk of cardio- and cerebrovascular events and death, presumably by promoting endothelial dysfunction and subclinical atherosclerosis. We hypothesized that plasma ADMA concentrations are positively related to common carotid artery intimal media thickness (CCA-IMT) and to internal carotid (ICA)/bulb-IMT.
We investigated the cross-sectional relations of plasma ADMA with CCA-IMT and ICA/bulb-IMT in 2958 Framingham Heart Study participants (mean age 58 years, 55% women).
In unadjusted analyses, ADMA was positively related to both CCA-IMT (β per SD increment 0.012, p<0.001) and ICA/bulb IMT (β per SD increment 0.059, p<0.001). In multivariable analyses (adjusting for age, sex, systolic blood pressure, antihypertensive treatment, smoking status, diabetes, body mass index (BMI), Total to HDL cholesterol ratio, log C-reactive protein, and serum creatinine), plasma ADMA was not associated with CCA-IMT (p=0.991), but remained significantly and positively related to ICA/bulb IMT (β per SD increment 0.0246, p=0.002).
In our large community-based sample, we observed that higher plasma ADMA concentrations were associated with greater ICA/bulb-IMT but not with CCA-IMT. These data are consistent with the notion that ADMA promotes subclinical atherosclerosis in a site-specific manner, with a greater proatherogenic influence at known vulnerable sites in the arterial tree.
Carotid Intimal Medial Thickness; Endothelium; Epidemiology; Risk Factors; Nitric Oxide
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.
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
Epidemiological data concerning atherosclerotic disease among older people in rural China are sparse. We seek to determine prevalence and cardiovascular risk factor profiles for peripheral artery disease (PAD) and carotid atherosclerosis (CAS) among Chinese older people living in a rural community.
This cross-sectional study included 1499 participants (age ≥60 years, 59.0% women) of the Confucius Hometown Aging Project in Shandong, China. From June 2010–July 2011, data were collected through interviews, clinical examinations, and laboratory tests. PAD was defined as an ankle-brachial index ≤0.9. Carotid intima-media thickness (cIMT) and carotid artery stenosis were assessed by ultrasonography. We defined moderate stenosis as carotid stenosis ≥50%, and severe stenosis as carotid stenosis ≥70%. cIMT≥1.81 mm was considered as an increased cIMT (a measure of CAS). Data were analyzed with multiple logistic models.
The prevalence was 5.7% for PAD, 8.9% for moderate stenosis, 1.8% for severe stenosis, and 11.2% for increased cIMT. After controlling for multiple potential confounders, diabetes, an increased low-density lipoprotein cholesterol (LDL-C)/high-density lipoprotein cholesterol (HDL-C) ratio, and hypertension were significantly or marginally associated with PAD. Ever smoking, hypertension, and an increased LDL-C/HDL-C ratio were significantly associated with an increased likelihood of increased cIMT. An increasing number of those cardiovascular risk factors were significantly associated with an increasing odds ratio of PAD and increased cIMT, respectively (p for linear trend <0.001).
Among Chinese older people living in a rural community, PAD, carotid artery stenosis, and an increased cIMT are relatively uncommon. Cardiovascular risk factor profiles for PAD and CAS are slightly different, with hypertension and an increased LDL-C/HDL-C ratio being associated with an increased likelihood of both PAD and increased cIMT.
Brachial pulse pressure (PP) has been found to be associated with markers of subclinical cardiovascular disease, including carotid intima–media thickness and left-ventricular mass index (LVMI), but it is unclear whether these associations are independent of traditional cardiovascular risk factors and of the steady, nonpulsatile component of blood pressure (BP). Moreover, it is unknown whether these associations are modified by gender, age, or race/ethnicity.
We used multivariate linear regression models to assess the relationship between brachial PP and three markers of subclinical cardiovascular disease (CVD) (common carotid intima–media thickness (CC-IMT), internal carotid intima–media thickness (IC-IMT), and LVMI) in four race/ethnic groups in the Multi-Ethnic Study of Atherosclerosis. The models were adjusted for traditional Framingham risk factors (age, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, diabetes, smoking status), use of lipid-lowering medication, use of antihypertensive medication, study site, and mean arterial pressure (MAP).
The assessment was done on 6,776 participants (2,612 non-Hispanic white, 1,870 African-American, 1,494 Hispanic, and 800 Chinese persons). The associations between brachial PP and CC-IMT, IC-IMT, and LVMI were significant in fully adjusted models. The three subclinical markers also showed significant interactions with gender (P < 0.0001), with stronger interactions in men. There was an interaction with age for LVMI (P = 0.004) and IC-IMT (P = 0.008). Race/ethnicity modified the association of PP with CC-IMT.
Brachial PP was independently associated with subclinical CVD after adjustment for cardiovascular risk factors and mean arterial pressure (MAP). The strength of the association differed significantly for strata of gender, age, and race/ethnicity.
pulse pressare; subclinical cardiovascular disease; carotid intima–media thickness; left ventricular mass index; aging; hypertension; arterial stiffness; blood pressure.
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
Few population studies have evaluated the associations of both coronary artery calcium (CAC) and carotid ultrasound with cardiovascular events, especially in adults > 70 years of age. At the Pittsburgh Field Center of the Cardiovascular Health Study, 559 men and women, mean age 80.2 (SD 4.1) years had CAC score assessed by electron beam computerized tomography scan and common and internal carotid intimal-medial wall thickness (CCA-IMT and ICA-IMT) by carotid ultrasound between 1998−2000 and were followed for total and incident cardiovascular disease events through June 2003. Crude rates and hazard ratios for total and incident events were examined with and without adjustment for cardiovascular risk factors. After 5 years, there were 127 cardiovascular disease events, 48 myocardial infarctions or cardiovascular disease deaths and 28 strokes or stroke deaths. Total and incident cardiovascular disease event rates were higher in each quartile of CAC and CCA-IMT, but not ICA-IMT. For total cardiovascular disease, the adjusted hazard ratio for the 4th vs. 1st quartile of CAC was 2.1 (95% CI = 1.2−3.9) and for CCA-IMT was 2.3 (95% CI = 1.3−4.1). The CCA-IMT was more strongly related to stroke risk than was CAC, though CAC was also an important predictor of stroke. No significant sex differences were found, though relative risks appeared to be stronger in women, especially for stroke. In conclusion, in these adults > 70 years of age, CAC and CCA-IMT had similar hazard ratios for total cardiovascular disease and coronary heart disease. The CCA-IMT was more strongly related to stroke than was CAC, but CAC was also a predictor of stroke.
calcium; cardiovascular diseases; coronary disease; prognosis
To explore predictors of change in measures of carotid atherosclerosis among rheumatoid arthritis (RA) patients without known cardiovascular disease (CVD) at baseline
RA patients underwent carotid ultrasonography at two timepoints, separated by an average of 3.2 ± 0.3 years. The associations of baseline and average patient characteristics with the average yearly change in mean maximal intima-medial thickness (IMT) of the common (CCA) and internal carotid arteries (ICA), and with incident or progressive plaque in the ICA/carotid bulb, were explored.
Among the 158 RA patients, maxCCA-IMT increased in 82% (median=16 μm/year; p<0.001) and maxICA-IMT increased in 70% (median=25 μm/year; p<0.001). Incident plaque was observed in 14% without baseline plaque [incidence rate=4.2/100 person-years (95% CI 1.61–6.82)]. Plaque progression was observed in 5% with baseline plaque. Among RA predictors, the adjusted average yearly change in maxCCA-IMT was significantly greater in patients with earlier RA vs. longer disease. Those prescribed TNF inhibitors at baseline had a 37% lower adjusted rate of maxCCA-IMT progression vs. non-users (14 vs. 22 μm/year; p=0.026). For maxICA-IMT, cumulative prednisone exposure was associated with progression [1.2 μm/year per gram (95% CI 0.1–2.4)] after adjustment, and was lower in patients prescribed statins concomitant with prednisone. Higher swollen joint count and higher average CRP were both associated with incident or progressive plaque, primarily in patients with elevated baseline CVD risk based on the Framingham score.
These prospective data provide evidence for inflammation as a contributor to subclinical atherosclerosis progression in RA, potentially modified favorably by TNF inhibitors and detrimentally by glucocorticoids.
Atherosclerosis; Inflammation; prediction; carotid ultrasound
We examined cross-sectional associations between sex hormones and carotid artery intimal-medial thickness (cIMT) and coronary artery calcium in women in the Multi-Ethnic Study of Atherosclerosis.
Serum testosterone, estradiol, sex hormone binding globulin (SHBG), and dehydroepiandrosterone levels were measured in 1,947 postmenopausal women aged 45-84 years (30% White, 14% Chinese-American, 31% Black, and 25% Hispanic) and not on hormone therapy. Using multiple linear regression we evaluated associations between log(sex hormone) levels and log(cIMT) adjusted for age, ethnicity, body mass index (BMI) and cardiac risk factors. Associations between sex hormone levels and the presence and extent of coronary calcium were evaluated.
Total and bioavailable testosterone were positively associated with common cIMT independent of age, BMI, hypertension, smoking, HDL-cholesterol, LDL-cholesterol and insulin sensitivity (p=0.009 and p=0.002 respectively). SHBG was negatively associated with common cIMT (p=0.001) but further adjustment for BMI, cardiovascular risk factors, and LDL- and HDL-cholesterol removed significance. Estradiol and dehydroepiandrosterone were not associated with common cIMT. Sex hormones were not associated with presence of coronary calcium. Among women with measurable coronary calcium, higher SHBG (p=0.012) and lower bioavailable testosterone (p=0.007) were associated with greater coronary calcium score. No heterogeneity by ethnicity was found. In postmenopausal women, testosterone is independently associated with greater common cIMT. SHBG is negatively associated and this may be mediated by LDL- and HDL-cholesterol. In contrast, SHBG and testosterone were associated with extent of coronary calcium but in the opposite direction compared to carotid intimal-medial thickness. These differences warrant further evaluation.
Gonadal steroid hormones; atherosclerosis; postmenopausal women; carotid intimal-medial thickness; coronary calcium
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