Evaluation of computerized edge tracking for quantifying intima-media thickness of the common carotid artery from B-mode ultrasound images

Carotid Artery Wall Echogenicity Measured by Gray Scale Median of the Intima-Media Complex From Childhood to Young Adulthood

BACKGROUND

Echogenicity of the carotid arterial wall, measured by gray scale median of the intima-media complex (IM-GSM), is a novel subclinical atherosclerosis marker with lower values indicating greater lipid deposition. Our longitudinal study investigated IM-GSM from childhood to adulthood and its associated risk factors.

METHODS AND RESULTS

A total of 240 participants from the Southern California CHS (Children's Health Study) underwent carotid artery ultrasounds in 2008 (mean age±SD): (11.2±0.6 years), and again around 2022 (24.2±1.6 years) to assess IM-GSM, carotid artery intima-media thickness, and carotid artery distensibility. Questionnaires and anthropometric and blood pressure measurements were completed by participants at both times. Mean and SD of IM-GSM were 108.2±24.6 in childhood and 75.6±15.8 in adulthood. Each 1-year increase in age was associated with -2.52 change in IM-GSM (95% CI, -2.76 to -2.27). Childhood and adulthood IM-GSMs were highly correlated (β=0.13 [95% CI, 0.05-0.22]). In childhood, Hispanic ethnicity, lower parental education levels and prenatal father smoking were significantly associated with lower IM-GSM. In adulthood, higher systolic blood pressure, carotid artery intima-media thickness, hypertension, and lower distensibility were significantly associated with lower IM-GSM. Weight status exhibited a consistent association with both childhood and adulthood IM-GSM. During the transition from childhood to adulthood, individuals who shifted from normal weight to overweight/obese or normal blood pressure to hypertension or experienced an increase in carotid artery intima-media thickness displayed lower levels of IM-GSM in adulthood.

CONCLUSIONS

IM-GSM decreases with age. Maintaining healthy weight and blood pressure levels in children could potentially aid in preventing subclinical atherosclerosis.

Association Between Cardiovascular Health and Subclinical Atherosclerosis Among Young Adults Using the American Heart Association's "Life's Essential 8" Metrics

BACKGROUND

This study investigated the association of American Heart Association's cardiovascular health guidelines Life's Essential 8 (LE8) and Life's Simple 7 (LS7) with carotid artery outcomes among young adults.

METHODS AND RESULTS

This cross-sectional study included 240 young adults (age 24.2±1.6 years) who underwent a carotid ultrasound between 2018 and 2022. LE8 score was calculated from 4 health factors (body mass index, non-high-density lipoprotein cholesterol, fasting glucose, and blood pressure), and 4 health behaviors (dietary intake, physical activity, tobacco use, and sleep). LS7 was calculated from 7 metrics (all LE8 metrics, except for sleep) with a simpler algorithm. Higher LE8 and LS7 scores both indicate better health and better adherence to American Heart Association guidelines. Carotid artery outcomes included carotid artery intima-media thickness, arterial stiffness (eg, distensibility), and echogenicity determined by grayscale median of the intima media complex. Results of linear regression analyses, adjusting for age, sex, ethnicity, and parents' highest degree, indicated that a 1-SD increase in LE8 score was associated with 12.14 μm lower carotid artery intima-media thickness (95% CI, -20.93 to 3.35), 1.17 (10-6×m2/N) greater distensibility (95% CI, 0.09-2.24), suggesting less arterial stiffness, and 2.66 μm greater grayscale median of the intima media complex (95% CI, 0.58-4.75), suggesting less lipid deposition. Analyses using LS7 score demonstrated comparable findings. Health factor metrics demonstrated stronger association with carotid artery outcomes, as compared with behavior metrics.

CONCLUSIONS

Greater adherence to the American Heart Association's cardiovascular health guidelines is associated with lower risk for subclinical atherosclerosis in young adults. LE8 and LS7 demonstrated comparable associations with carotid artery outcomes.

Association of HIV and HCV Infection With Carotid Artery Plaque Echomorphology in the MACS/WIHS Combined Cohort Study

BACKGROUND

HIV and hepatitis C virus (HCV) are associated with increased risk of carotid artery atherosclerotic plaque and stroke. We examined associations of HIV- and HCV-related factors with echomorphologic features of carotid artery plaque.

METHODS

This cross-sectional study included participants from the MACS (Multicenter AIDS Cohort Study)/WIHS (Women's Interagency HIV Study) Combined Cohort Study who underwent high-resolution B-mode carotid artery ultrasound. Plaques were characterized from 6 areas of the right carotid artery. Poisson regression controlling for demographic and cardiometabolic risk factors determined adjusted prevalence ratios (aPRs) and 95% CIs for associations of HIV- and HCV-related factors with echomorphologic features.

RESULTS

Of 2655 participants (65% women, median age 44 [interquartile range, 37-50] years), 1845 (70%) were living with HIV, 600 (23%) were living with HCV, and 425 (16%) had carotid plaque. There were 191 plaques identified in 129 (11%) women with HIV, 51 plaques in 32 (7%) women without HIV, 248 plaques in 171 (28%) men with HIV, and 139 plaques in 93 (29%) men without HIV. Adjusted analyses showed that people with HIV and current CD4+ count <200 cells/µL had a significantly higher prevalence of predominantly echolucent plaque (aPR, 1.86 [95% CI, 1.08-3.21]) than those without HIV. HCV infection alone (aPR, 1.86 [95% CI, 1.08-3.19]) and HIV-HCV coinfection (aPR, 1.75 [95% CI, 1.10-2.78]) were each associated with higher prevalence of predominantly echogenic plaque. HIV-HCV coinfection was also associated with higher prevalence of smooth surface plaque (aPR, 2.75 [95% CI, 1.03-7.32]) compared with people without HIV and HCV.

CONCLUSIONS

HIV with poor immunologic control, as well as HCV infection, either alone or in the presence of HIV, were associated with different echomorphologic phenotypes of carotid artery plaque.

Comparison of Cardiovascular Disease Risk Factors Between 2 Subclinical Atherosclerosis Measures in Healthy Postmenopausal Women: Carotid Artery Wall Thickness and Echogenicity: Carotid Artery Wall Thickness and Echogenicity

OBJECTIVES

Although carotid artery intima media thickness (CIMT) is a widely used determinant of subclinical atherosclerosis, gray-scale median of the intima-media complex (IM-GSM) of the common carotid artery is a relatively novel measure of echogenicity reflecting composition of the arterial wall. It is important to compare cardiovascular disease (CVD) risk factor correlates across CIMT and IM-GSM to determine whether these measures reflect distinct aspects of atherosclerosis.

METHODS

Baseline information from a completed randomized clinical trial of 643 healthy postmenopausal women without clinically apparent CVD was included in this cross-sectional study. The women were on average ± SD 61 ± 7 years old, and predominantly non-Hispanic White. CIMT and IM-GSM were measured by high-resolution B-mode ultrasonogram in the far wall of the right common carotid artery. CVD risk factors including age, race, body mass index (BMI), smoking, weekly hours of physical activity, systolic (SBP) and diastolic blood pressure (DBP), lipids, glucose, and inflammatory markers were measured at baseline. Linear regression models were used to assess associations of CVD risk factors with CIMT and IM-GSM. Multivariable models included groups of risk factors added one at a time with and withoutbasic demographic factors (age, race, BMI, physical activity) with model R2 values compared between CIMT and IM-GSM.

RESULTS

In multivariable analysis, age, Black race, BMI, SBP, and DBP were associated with CIMT (all P < .05), whereas age, Hispanic race, BMI, SBP, physical activity, LDL-cholesterol, and leptin were correlates of IM-GSM (all P < .05). Adjusted for age, race, BMI, and physical activity, the R2 value for SBP was greater for CIMT association, whereas R2 values for lipids, glucose, inflammatory markers, and adipokines were greater for IM-GSM associations.

CONCLUSIONS

CIMT and IM-GSM assess different attributes of subclinical atherosclerosis. Integrating both measures may provide improved assessment of atherosclerosis in asymptomatic individuals.

Subclinical carotid artery atherosclerosis and cognitive function in older adults

Background

The combined effects of increased life expectancy and the considerable number of persons reaching old age will magnify the dementia epidemic in the USA. Demonstration that subclinical atherosclerosis precedes and is associated with cognitive impairment suggests a modifiable risk factor for age-associated cognitive impairment and dementia. The purpose of this study is to determine whether subclinical atherosclerosis as measured by carotid artery intima-media thickness (CIMT) is associated with changes in cognitive function over time in older adults.

Methods

This study combined longitudinal data from three clinical trials conducted between 2000 and 2013: the B-Vitamin Atherosclerosis Intervention Trial (BVAIT), the Women’s Isoflavone Soy Health (WISH) trial, and the Early versus Late Intervention Trial with Estradiol (ELITE). Participants were recruited from the general population in the Greater Los Angeles area and were free of cardiovascular disease and diabetes; no cognitive or psychiatric exclusion criteria were specified. The same standardized protocol for ultrasound image acquisition and measurement of CIMT was used in all trials. CIMT measurements performed at baseline and 2.5 years were used in these analyses. Cognitive function was assessed at baseline and 2.5 years using a battery of 14 standardized cognitive tests. All clinical trials were conducted at the University of Southern California Atherosclerosis Research Unit, Los Angeles, and had at least 2.5 years of cognitive follow-up.

Results

A total of 308 men and 1187 women, mean age of 61 years, were included in the combined longitudinal dataset for the primary analysis. No associations were found between CIMT and cognitive function at baseline or at 2.5 years. There was a weak inverse association between CIMT measured at baseline and change in global cognition assessed over 2.5 years (β (SE) = − 0.056 (0.028) units per 0.1 mm CIMT, 95% CI − 0.110, − 0.001, p = 0.046). No associations between CIMT at baseline and changes in executive function, verbal memory, or visual memory were found.

Conclusions

In this sample of healthy older adults, our findings suggest an association between subclinical atherosclerosis and change in global cognitive function over 2.5 years. Stronger associations were observed longitudinally over 2.5 years than cross-sectionally. When analysis was stratified by age group (<65 and ≥65 years old), the inverse association remained statistically significant for participants in the older age group. Subclinical atherosclerosis of the carotid artery may be a modifiable correlate of cognitive decline in middle and older age.

Trial registration

BVAIT, NCT00114400. WISH, NCT00118846. ELITE, NCT00114517.

Effect of menopausal hormone therapy on arterial wall echomorphology: Results from the Early versus Late Intervention Trial with Estradiol (ELITE)

OBJECTIVE

To evaluate the effect of hormone therapy (HT) on arterial wall composition by ultrasound.

BACKGROUND

The effect of HT on the progression of subclinical atherosclerosis has been well-described using measurements of common carotid artery (CCA) wall thickness. However, it is unknown whether the change in arterial wall anatomic structure is accompanied by an effect of HT on arterial wall composition.

METHODS

A total of 643 healthy postmenopausal women divided into two strata according to the time since menopause (<6 years, the early-postmenopause group; or >10 years, the late-postmenopause group) were randomized to receive either active treatment or placebo. For hysterectomized women, the active treatment was oral micronized 17β-estradiol 1 mg/day; for women with a uterus, 4% vaginal micronized progesterone gel 45 mg/day for 10 days each month was added to the estradiol regimen. Gray-scale median of the CCA intima-media complex (IM-GSM), a (unitless) measurement of arterial wall composition based on echogenicity, was determined by high-resolution B-mode ultrasonography. Lower IM-GSM, or less echogenicity, indicates more atherosclerosis. IM-GSM and serum estradiol (E2) concentration were assessed every 6 months over a median 4.8-year trial period. Linear mixed effects regression models were used for all analyses.

RESULTS

Overall, IM-GSM progression/year had a negative trajectory, reflecting reduction in echogenicity over time (worsening atherosclerosis). HT effects on IM-GSM progression/year differed by postmenopause strata (interaction p-value = 0.02). IM-GSM progression/year (95% CI) in the early postmenopause group randomized to HT was -0.50 (-0.82, -0.18)/year compared with -1.47 (-1.81, -1.13)/year among those randomized to placebo (p-value <0.0001). In the late postmenopause group, the annual IM-GSM progression rate did not significantly differ between HT and placebo (p = 0.28). Higher mean on-trial E2 (pg/ml) levels were associated with higher IM-GSM progression, indicating less atherosclerosis progression in all women (β (95% CI) = 0.006 (0.0003, 0.01), p = 0.04). For each pg/dl E2, IM-GSM progression/year was 0.007 ((-0.0002, 0.01), p = 0.056) in the early and 0.003 ((-0.006, 0.01), p = 0.50) in the late postmenopause group (interaction p-value = 0.51). CIMT progression rate (μm/year) was significantly inversely associated with the IM-GSM progression (β (95% CI) = -4.63 (-5.6, -3.7), p < 0.001).

CONCLUSIONS

HT, primarily with oral estradiol, reduced atherogenic progression of arterial wall composition in healthy postmenopausal women who were within 6 years from menopause.

TRIAL REGISTRATION NUMBER

NCT01553084.

Childhood traffic-related air pollution and adverse changes in subclinical atherosclerosis measures from childhood to adulthood

BACKGROUND

Chronic exposure to air pollutants is associated with increased risk of cardiovascular disease (CVD) among adults. However, little is known about how air pollution may affect the development of subclinical atherosclerosis in younger populations. Carotid artery intima-media thickness (CIMT) is a measure of subclinical atherosclerosis that provides insight into early CVD pathogenesis.

METHODS

In a pilot study of 70 participants from the Southern California Children's Health Study, we investigated CIMT progression from childhood to adulthood. Using carotid artery ultrasound images obtained at age 10 and follow-up images at age 21-22, we examined associations between childhood ambient and traffic-related air pollutants with changes in CIMT over time and attained adult CIMT using linear mixed-effects models adjusted for potential confounders. Average residential childhood exposures (i.e., birth to time of measurement at 10-11 years) were assigned for regional, ambient pollutants (ozone, nitrogen dioxide, particulate matter, interpolated from regulatory air monitoring data) and traffic-related nitrogen oxides (NO_x) by road class (modeled using the CALINE4 line source dispersion model). Traffic density was calculated within a 300-m residential buffer.

RESULTS

For each 1 standard deviation (SD) increase in childhood traffic-related total NO_x exposure, we observed greater yearly rate of change in CIMT from childhood to adulthood (β: 2.17 μm/yr, 95% CI: 0.78-3.56). Increases in annual rate of CIMT change from childhood to adulthood also were observed with freeway NO_x exposure (β: 2.24 μm/yr, 95% CI: 0.84-3.63) and traffic density (β: 2.11 μm/yr, 95% CI: 0.79-3.43). Traffic exposures were also related to increases in attained CIMT in early adulthood. No associations of CIMT change or attained level were observed with ambient pollutants.

CONCLUSIONS

Overall, we observed adverse changes in CIMT over time in relation to childhood traffic-related NO_x exposure and traffic density in our study population. While these results must be cautiously interpreted given the limited sample size, the observed associations of traffic measures with CIMT suggest a need for future studies to more fully explore this relationship.

Nattokinase atherothrombotic prevention study: A randomized controlled trial

BACKGROUND

Described to be antithrombotic and antihypertensive, nattokinase is consumed for putative cardiovascular benefit. However, no large-scale, long-term cardiovascular study has been conducted with nattokinase supplementation.

OBJECTIVE

To determine the effect of nattokinase on subclinical atherosclerosis progression and atherothrombotic biomarkers.

METHODS

In this double-blinded trial, 265 individuals of median age 65.3 years, without clinical evidence of cardiovascular disease (CVD) were randomized to oral nattokinase 2,000 fibrinolytic units or matching placebo. Primary outcome was rate of change in subclinical atherosclerosis measured by serial carotid ultrasound every 6 months as carotid artery intima-media thickness (CIMT) and carotid arterial stiffness (CAS). Additional outcomes determined at least every 6 months were clinical parameters including blood pressure and laboratory measures including metabolic factors, blood rheology parameters, blood coagulation and fibrinolysis factors, inflammatory markers and monocyte/macrophage cellular activation markers.

RESULTS

After median 3 years of randomized treatment, annualized rate of change in CIMT and CAS did not significantly differ between nattokinase supplementation and placebo. Additionally, there was no significant effect of nattokinase supplementation on blood pressure or any laboratory determination.

CONCLUSIONS

Results of this trial show that nattokinase supplementation has a null effect on subclinical atherosclerosis progression in healthy individuals at low risk for CVD.

Improving Blood Vessel Tortuosity Measurements via Highly Sampled Numerical Integration of the Frenet-Serret Equations

Measures of vascular tortuosity-how curved and twisted a vessel is-are associated with a variety of vascular diseases. Consequently, measurements of vessel tortuosity that are accurate and comparable across modality, resolution, and size are greatly needed. Yet in practice, precise and consistent measurements are problematic-mismeasurements, inability to calculate, or contradictory and inconsistent measurements occur within and across studies. Here, we present a new method of measuring vessel tortuosity that ensures improved accuracy. Our method relies on numerical integration of the Frenet-Serret equations. By reconstructing the three-dimensional vessel coordinates from tortuosity measurements, we explain how to identify and use a minimally-sufficient sampling rate based on vessel radius while avoiding errors associated with oversampling and overfitting. Our work identifies a key failing in current practices of filtering asymptotic measurements and highlights inconsistencies and redundancies between existing tortuosity metrics. We demonstrate our method by applying it to manually constructed vessel phantoms with known measures of tortuousity, and 9,000 vessels from medical image data spanning human cerebral, coronary, and pulmonary vascular trees, and the carotid, abdominal, renal, and iliac arteries.

Brief Report: Cystatin C-Based Estimation of Glomerular Filtration Rate and Association With Atherosclerosis Imaging Markers in People Living With HIV

INTRODUCTION

Reduced estimated glomerular filtration rate (eGFR) is associated with increased risk of cardiovascular disease among people living with HIV (PLWH). It is unclear whether eGFR equations incorporating cystatin C (CysC) measurements are more predictive of preclinical cardiovascular disease than those using only creatinine (Cr).

OBJECTIVES

The study aimed to determine which of the 3 Chronic Kidney Disease Epidemiology (CKD-EPI) eGFR equations is most associated with carotid intima media thickness (CIMT) and coronary artery calcium (CAC) score.

METHODS

This cross-sectional analysis of pooled data from 3 large cohorts compared the associations between the 3 CKD-EPI eGFR equations (Cr, CysC, and Cr-CysC) with CIMT and CAC score using multivariable regression analysis. eGFR and CIMT were analyzed as continuous variables. CAC scores were analyzed as a binary variable (detectable calcification versus nondetectable) and as a log10 Agatston score in those with detectable CAC.

RESULTS

Thousand four hundred eighty-seven participants were included, and of these 910 (562 HIV+ and 348 HIV-) had CIMT measurements and 366 (296 HIV+ and 70 HIV-) had CAC measurements available. In HIV- participants, GFR estimated by any CKD-EPI equation did not significantly correlate with CIMT or CAC scores. When PLWH were analyzed separately including HIV-specific factors, only GFR estimated using Cr-Cys C correlated with CIMT [β= -0.90, 95% CI: (-1.67 to -0.13) μm; P = 0.023]. Similarly, eGFR correlated with Agatston scores only when using cystatin C-based eGFR [β= -8.63, 95% CI: (-16.49 to -0.77) HU; P = 0.034]. Associations between other eGFR formulas and CAC did not reach statistical significance.

CONCLUSIONS

In PLWH, preclinical atherosclerosis may be more closely correlated with eGFR using formulae that incorporate CysC measurements than Cr alone.

Angiogenic Factors and Long-Term Cardiovascular Risk in Women That Developed Preeclampsia During Pregnancy

Preeclampsia is caused by placental impairment with increased expression of sFlt-1 (soluble fms-like tyrosine kinase 1) and decreased PlGF (placental growth factor); it has been associated with cardiovascular morbidity and mortality later in life, but the underlying mechanism remains unknown. The aim of this study was to determine whether sFlt-1 and PlGF levels during preeclampsia are associated to long-term cardiovascular risk. We prospectively recruited 43 women with previous preeclampsia and 21 controls with uncomplicated pregnancies. Cardiovascular risk assessment ≈12 years later included maternal hemodynamic, cardiac function and structure, biomarker analysis, and carotid-intima thickness evaluation. Women with previous preeclampsia had higher prevalence of hypertensive disorders and dyslipidemia than controls. In addition, they had worse global longitudinal strain, thicker left ventricular septal and posterior walls, more myocardial mass and increased carotid intima-media thickness compared with controls. PlGF during pregnancy correlated positively with high-density lipoprotein (r=0.341; P=0.006), and negatively with global longitudinal strain (r=-0.581; P<0.001), carotid intima-media thickness (r=-0.251; P=0.045), and mean arterial blood pressure (r=-0.252; P=0.045), when adjusted by study group. sFlt correlated negatively with high-density lipoprotein (r=-0.372; P=0.002) and apolipoprotein A-1 (r=-0.257; P=0.040), and positively with carotid intima-media thickness (r=0.269; P=0.032) and left ventricular posterior wall thickness (r=0.368; P=0.003). The antiangiogenic state present in preeclampsia is related to greater prevalence of cardiovascular risk factors ≈12 years after delivery. The knowledge of altered angiogenic factors may help detect women with a higher risk for premature cardiovascular disease, who will require earlier follow-up after delivery.

Increased blood pressure is associated with increased carotid artery intima-media thickness in children with repaired coarctation of the aorta

OBJECTIVES

The intima-media thickness of the common carotid artery (cIMT) is a good noninvasive surrogate marker for cardiovascular disease. Regular cIMT monitoring in children with congenital heart disease has great potential. We sought to determine which anthropomorphic and haemodynamic variables were significantly associated with the cIMT in paediatric patients with obesity and children with repaired coarctation of the aorta (CoA).

METHODS

We measured the cIMT in 143 children aged 5 to less than 18 years including normal weight controls (n = 44), children with overweight/obesity (n = 73) and children with repaired CoA (n = 26). cIMT was compared and the association between the cIMT and patient characteristics, including obesity and blood pressure (BP), was investigated.

RESULTS

BMI z score, sex and the presence of CoA were significant independent predictors of cIMT. The cIMT was significantly greater in children with overweight/obesity (0.53 ± 0.06 mm) relative to normal weight controls (0.51 ± 0.04 mm), as well as in CoA patients with abnormally high BP (0.57 ± 0.08 mm) versus CoA patients with normal BP (0.52 ± 0.05 mm) and controls (0.51 ± 0.04 mm). CoA patients with normal BP did not have significantly increased cIMT.

CONCLUSION

cIMT was positively associated with BMI z score, male sex and CoA repair in children. The increased cIMT in children with repaired CoA was because of those with abnormally high BP, which was masked in clinic for most of these patients. These findings warrant further investigations into the cIMT and other atherosclerotic risk factors to determine their potential clinical impact in these highly susceptible patients.

Imaging modalities to diagnose carotid artery stenosis: progress and prospect

In the past few decades, imaging has been developed to a high level of sophistication. Improvements from one-dimension (1D) to 2D images, and from 2D images to 3D models, have revolutionized the field of imaging. This not only helps in diagnosing various critical and fatal diseases in the early stages but also contributes to making informed clinical decisions on the follow-up treatment profile. Carotid artery stenosis (CAS) may potentially cause debilitating stroke, and its accurate early detection is therefore important. In this paper, the technical development of various CAS diagnosis imaging modalities and its impact on the clinical efficacy is thoroughly reviewed. These imaging modalities include duplex ultrasound (DUS), computed tomography angiography (CTA) and magnetic resonance angiography (MRA). For each of the imaging modalities considered, imaging methodology (principle), critical imaging parameters, and the extent of imaging the vulnerable plaque are discussed. DUS is usually the initial recommended CAS diagnostic examination. However, for the therapeutic intervention, either MRA or CTA is recommended for confirmation, and for added information on intracranial cerebral circulation and aortic arch condition for procedural planning. Over the past few decades, the focus of CAS diagnosis has also shifted from pure stenosis quantification to plaque characterization. This has led to further advancement in the existing imaging tools and development of other potential imaging tools like Optical coherence tomography (OCT), photoacoustic tomography (PAT), and infrared (IR) thermography.

Associations of edge-detected and manual-traced common carotid artery intima-media thickness with incident peripheral artery disease: The Multi-Ethnic Study of Atherosclerosis

Common carotid artery (CCA) intima-media thickness (IMT) is associated with coronary heart disease and can be measured on ultrasound images either by hand or with an automated edge detector. The association of CCA IMT with incident peripheral artery disease (PAD) is poorly studied. We studied 5467 participants of the Multi-Ethnic Study of Atherosclerosis composed of non-Hispanic white, Chinese, Hispanic, and African American participants with a mean age of 61.9 years (47.8% men). Framingham Risk Factors, manual-traced IMT (mt-IMT), and edge-detected IMT (ed-IMT) were entered into multivariable Cox proportional hazards models with incident PAD as the outcome. There were 87 events during a median follow-up of 12.2 years. In fully adjusted models and expressing the hazard ratios (HR) as an increment in SD values, both mt-IMT and ed-IMT were significantly associated with incident PAD: HR 1.36 (95% CI: 1.15, 1.61) and 1.29 (95% CI: 1.04, 1.60), respectively. We conclude that ed- and mt-CCA IMT measurements are associated with incident PAD. ClinicalTrials.gov Identifier: NCT00063440.

Differential Effect of Plasma Estradiol on Subclinical Atherosclerosis Progression in Early vs Late Postmenopause

CONTEXT

The Early vs Late Intervention Trial with Estradiol showed that hormone therapy (HT) reduced progression of atherosclerosis when initiated in early but not in late postmenopause.

OBJECTIVE

This posttrial analysis examined the association between plasma estradiol (E2) levels and atherosclerosis determined by rate of change in carotid artery intima-media thickness (CIMT) and tested whether this association is equally evident in early (<6 years) vs late (≥10 years) postmenopause.

DESIGN

Randomized controlled trial stratified by time since menopause (ClinicalTrials.gov no. NCT00114517). Mixed-effects linear models tested the association of E2 levels with CIMT rate of change.

SETTING

Los Angeles, California.

PARTICIPANTS

Healthy women in postmenopause.

INTERVENTION

Oral E2 with/without cyclic vaginal progesterone.

MAIN OUTCOME MEASURES

Plasma E2 levels and CIMT assessed every 6 months over an average of 4.8 years.

RESULTS

Among 596 women in postmenopause, higher E2 level was inversely associated with CIMT progression in those in early postmenopause (P = 0.041) and positively associated with CIMT progression in those in late postmenopause (P = 0.006) (P for interaction <0.001). CIMT progression rates for the lowest vs highest quartile of E2 levels among women in early postmenopause were 8.5 and 7.2 μm/y, respectively , whereas among women in late postmenopause they were 9.8 and 11.7 μm/y, respectively.

CONCLUSION

E2 levels were differentially associated with atherosclerosis progression according to timing of HT initiation. With higher E2 levels, CIMT progression rate was decreased among women in early postmenopause but increased among women in late postmenopause. These results support the timing hypothesis of HT initiation on cardiovascular benefit, with reduced atherosclerosis progression for initiation during early postmenopause.

A novel NMR-based assay to measure circulating concentrations of branched-chain amino acids: Elevation in subjects with type 2 diabetes mellitus and association with carotid intima media thickness

OBJECTIVES

Plasma branched-chain amino acid (BCAA) levels, measured on nuclear magnetic resonance (NMR) metabolomics research platforms or by mass spectrometry, have been shown to be associated with type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD). We developed a new test for quantification of BCAA on a clinical NMR analyzer and used this test to determine the clinical correlates of BCAA in 2 independent cohorts.

DESIGN AND METHODS

The performance of the NMR-based BCAA assay was evaluated. A method comparison study was performed with mass spectrometry (LC-MS/MS). Plasma BCAA were measured in the Insulin Resistance Atherosclerosis Study (IRAS, n = 1209; 376 T2DM subjects) and in a Groningen cohort (n = 123; 67 T2DM subjects). In addition, carotid intima media thickness (cIMT) was measured successfully in 119 subjects from the Groningen cohort.

RESULTS

NMR-based BCAA assay results were linear over a range of concentrations. Coefficients of variation for inter- and intra-assay precision ranged from 1.8-6.0, 1.7-5.4, 4.4-9.1, and 8.8-21.3%, for total BCAA, valine, leucine, and isoleucine, respectively. BCAA quantified from the same samples using NMR and LC-MS/MS were highly correlated (R² = 0.97, 0.95 and 0.90 for valine, leucine and isoleucine). In both cohorts total and individual BCAA were elevated in T2DM (P = 0.01 to ≤0.001). Moreover, cIMT was associated with BCAA independent of age, sex, T2DM and metabolic syndrome (MetS) categorization or alternatively of individual MetS components.

CONCLUSIONS

BCAA levels, measured by NMR in the clinical laboratory, are elevated in T2DM and may be associated with cIMT, a proxy of subclinical atherosclerosis.

Follicle-Stimulating Hormone Levels and Subclinical Atherosclerosis in Older Postmenopausal Women

Recent studies of perimenopausal women suggest that follicle-stimulating hormone (FSH) levels may be associated with atherosclerosis, independent of estradiol. Whether FSH is related to atherosclerosis in older postmenopausal women, who have completed the menopausal transition, remains unknown. We assessed the relationship of serum FSH and estradiol levels with carotid artery intima-media thickness (IMT) among 587 postmenopausal participants in the Kuopio Ischemic Heart Disease Risk Factor Study (Kuopio, Finland). Participants were aged 53-73 years and not using hormone therapy at baseline (1998-2001). Mean IMT was measured via high-resolution ultrasonography. We observed a significant inverse association between FSH levels and IMT. Mean IMTs among women in quartiles 1-4 of FSH were 0.94 mm, 0.91 mm, 0.87 mm, and 0.85 mm, respectively (P-trend < 0.001). After adjustment for age, estradiol, testosterone, body mass index (weight (kg)/height (m)2), lipids, and other factors, FSH levels remained significantly associated with IMT (regression coefficients for quartiles 2-4 vs. quartile 1 were -0.038, -0.045, and -0.062, respectively; P-trend = 0.01). Findings were strongest in women aged 64-73 years (P-trend = 0.006) and did not vary by body mass index. In contrast, estradiol levels were not related to IMT. In summary, high postmenopausal FSH levels were associated with a lower atherosclerotic burden, independent of estradiol, adiposity, and other factors. Our findings warrant replication and the further exploration of potential underlying mechanisms.

Carotid Artery Intima-Media Thickness and Subclinical Atherosclerosis in Women With Remote Histories of Preeclampsia: Results From a Rochester Epidemiology Project-Based Study and Meta-analysis

OBJECTIVE

To measure carotid artery intima-media thickness (CIMT), a marker of subclinical atherosclerosis, in postmenopausal women with and without histories of preeclampsia and to synthesize these results with those from prior studies of CIMT performed 10 or more years after preeclamptic pregnancies.

PATIENTS AND METHODS

Forty women (median age, 59 years) with histories of preeclampsia and 40 with histories of normotensive pregnancy (confirmed by medical record review) were selected from women who resided and gave birth in Olmsted County, Minnesota, between January 1, 1976, and December 31, 1982. The participants were identified and recruited in 2014-2015, and CIMT was measured by B-mode ultrasonography. Meta-analysis included CIMT studies that were performed 10 or more years after preeclamptic pregnancies and which were identified through PubMed, EMBASE, and Web of Science. Heterogeneity was assessed using the I² statistic. Standardized mean difference was used as a measure of effect size.

RESULTS

Carotid artery intima-media thickness, expressed as a median (interquartile range), was greater in the preeclamptic than in the normotensive group (0.80 mm [0.75-0.85 mm] vs 0.73 mm [0.70-0.78]; P=.004); the odds of having CIMT higher than threshold (0.77 mm) was statistically significant after adjusting for confounding factors (odds ratio, 3.17; 95% CI, 1.10-9.14). A meta-analysis of 10 studies conducted 10 or more years post partum included 813 women with and 2874 without histories of preeclampsia. Carotid artery intima-media thickness was greater among women with histories of preeclampsia, with a standardized mean difference of 0.18 and 95% CI of 0.05 to 0.30 mm (P=.004).

CONCLUSION

Among women with histories of preeclampsia, CIMT may identify those with subclinical atherosclerosis, thus offering an opportunity for early intervention.

Advanced Glycation End Products, Oxidation Products, and the Extent of Atherosclerosis During the VA Diabetes Trial and Follow-up Study

OBJECTIVE

To determine whether plasma levels of advanced glycation end products and oxidation products play a role in the development of atherosclerosis in patients with type 2 diabetes (T2D) over nearly 10 years of the VA Diabetes Trial and Follow-up Study.

RESEARCH DESIGN AND METHODS

Baseline plasma levels of methylglyoxal hydroimidazolone, Nε-carboxymethyl lysine, Nε-carboxyethyl lysine (CEL), 3-deoxyglucosone hydroimidazolone and glyoxal hydroimidazolone (G-H1), 2-aminoadipic acid (2-AAA), and methionine sulfoxide were measured in a total of 411 participants, who underwent ultrasound assessment of carotid intima-media thickness (CIMT), and computed tomography scanning of coronary artery calcification (CAC) and abdominal aortic artery calcification (AAC) after an average of 10 years of follow-up.

RESULTS

In risk factor-adjusted multivariable regression models, G-H1 was associated with the extent of CIMT and CAC. In addition, 2-AAA was strongly associated with the extent of CAC, and CEL was strongly associated with the extent of AAC. The combination of specific advanced glycation end products and oxidation products (G-H1 and 2-AAA) was strongly associated with all measures of subclinical atherosclerosis.

CONCLUSIONS

Specific advanced glycation end products and metabolic oxidation products are associated with the severity of subclinical atherosclerosis over the long term and may play an important role in the "negative metabolic memory" of macrovascular complications in people with long-standing T2D.

Bone Mineral Density Is Positively Related to Carotid Intima-Media Thickness: Findings From a Population-Based Study in Adolescents and Premenopausal Women

Osteoporosis and cardiovascular disease (CVD) are both common causes of morbidity and mortality. Previous studies, mainly of people older than 60 years, suggest a relationship between these conditions. Our aim was to determine the association between bone characteristics and CVD markers in younger and middle-aged individuals. Women (n = 3366) and their adolescent offspring (n = 4368) from the UK population-based cohort study, Avon Longitudinal Study of Parents and Children (ALSPAC), were investigated. We measured total body (TB) and hip bone mineral density (BMD), TB bone area (BA) and bone mineral content (BMC) by dual-energy X-ray absorptiometry (DXA), and carotid intima-media thickness (cIMT) by high-resolution ultrasound. Arterial distensibility was calculated as the difference between systolic and diastolic arterial diameters. Linear regression determined associations between bone exposures and cIMT (in adolescents) and both cIMT and arterial distensibility (in women), generating partial correlation coefficients. Mean (SD) age of women was 48 (4.2) years, body mass index (BMI) was 26.2 (5.0) kg/m² , and 71% were premenopausal. In confounder-adjusted analyses (age, height, lean mass, fat mass, menopause, smoking, estrogen replacement, calcium/vitamin D supplementation, and education) TB and hip BMD were both positively associated with cIMT (0.071 [0.030, 0.112], p = 0.001; 0.063 [0.025, 0.101], p = 0.001, respectively). Femoral neck BMD and TB BMD, BMC, and BA were positively associated with arterial distensibility. Mean (SD) age of adolescents was 17 (0.4) years, BMI was 23 (4.1) kg/m² , and 44.5% were male. Total hip and TB measurements were positively associated with cIMT, with similar magnitudes of association to those found in their mothers. In contrast to most published findings, we identified weak positive associations between BMD and cIMT in predominantly premenopausal women and their adolescent offspring. We found greater femoral neck BMD and TB DXA measurements to be associated with reduced arterial stiffness. Rather than a relationship with preclinical atherosclerosis, in these relatively young populations, we speculate our associations between BMD, cIMT, and arterial distensibility may reflect a shared relationship between bone and vascular growth and development. © 2016 American Society for Bone and Mineral Research.

Prenatal Air Pollution Exposures, DNA Methyl Transferase Genotypes, and Associations with Newborn LINE1 and Alu Methylation and Childhood Blood Pressure and Carotid Intima-Media Thickness in the Children's Health Study

BACKGROUND

Although exposure to ambient air pollutants increases cardiovascular disease risk in adults little is known about the effects of prenatal exposure. Genetic variation and epigenetic alterations are two mechanisms that may influence the effects of early-life exposures on cardiovascular phenotypes.

OBJECTIVES

We investigated whether genetic and epigenetic variation modify associations between prenatal air pollution on markers of cardiovascular risk in childhood.

METHODS

We used linear regression analysis to investigate the associations between prenatal pollutants (PM2.5, PM10, NO2, O3), long interspersed nuclear elements (LINE1) and AluYb8 DNA methylation levels measured in newborn blood spot tests, and carotid intima-media thickness (CIMT) and blood pressure (BP) in 459 participants as part of the Children's Health Study. Interaction terms were also included to test for effect modification of these associations by genetic variation in methylation reprogramming genes.

RESULTS

Prenatal exposure to NO2 in the third trimester of pregnancy was associated with higher systolic BP in 11-year-old children. Prenatal exposure to multiple air pollutants in the first trimester was associated with lower DNA methylation in LINE1, whereas later exposure to O3 was associated with higher LINE1 methylation levels in newborn blood spots. The magnitude of associations with prenatal air pollution varied according to genotype for 11 SNPs within DNA methyltransferase 1 (DNMT1), DNA methyltransferase 3 Beta (DNMT3B), Tet methylcytosine dioxygenase 2 (TET2), and Thymine DNA glycosylase (TDG) genes. Although first-trimester O3 exposure was not associated with CIMT and systolic BP overall, associations within strata of DNMT1 or DNMT3B were observed, and the magnitude and the direction of these associations depended on DNMT1 genotypes.

CONCLUSIONS

Genetic and epigenetic variation in DNA methylation reprogramming genes and in LINE1 retrotransposons may play important roles in downstream cardiovascular consequences of prenatal air pollution exposure. Citation: Breton CV, Yao J, Millstein J, Gao L, Siegmund KD, Mack W, Whitfield-Maxwell L, Lurmann F, Hodis H, Avol E, Gilliland FD. 2016. Prenatal air pollution exposures, DNA methyl transferase genotypes, and associations with newborn LINE1 and Alu methylation and childhood blood pressure and carotid intima-media thickness in the Children's Health Study. Environ Health Perspect 124:1905-1912; http://dx.doi.org/10.1289/EHP181.

Intima-media thickness: indicator of cardiovascular risk and measure of the extent of atherosclerosis

The measurement of intima-media thickness (IMT) of large superficial arteries, especially the carotid, using high-resolution B-mode ultrasonography has emerged as one of the methods of choice for determining the anatomic extent of atherosclerosis and for assessing cardiovascular risk. IMT measurement obtained by ultrasonography correlates very well with pathohistologic measurements and the reproducibility of this technique is good. Population studies have shown a strong correlation between carotid IMT and several cardiovascular risk factors, and it has also been found to be associated with the extent of atherosclerosis and end-organ damage of high-risk patients. Therefore, increased carotid IMT is a measure of athero-sclerotic burden and a predictor of subsequent events. Because of its quantitative value, carotid IMT measurement is more and more frequently used in clinical trials to test the effects of different preventive measures, including drugs. More recently, there has been interest in the clinical use of this technique for detecting preclinical (asymptomatic) atherosclerosis and for identifying subjects at high risk. Measurement of carotid IMT could influence a clinician to intervene with medication and to use more aggressive treatment of risk factors in primary prevention, and in patients with atherosclerotic disease in whom there is evidence of progression and extension of atherosclerotic disease. For more extensive use of this method in clinical practice a consensus concerning the standardization of methods of measurement and precise definition of threshold between normal and pathologic IMT value is urgently needed.

Effect of comprehensive cardiovascular disease risk management on longitudinal changes in carotid artery intima-media thickness in a community-based prevention clinic

INTRODUCTION

The aim of the study was to examine changes in carotid intima-media thickness (CIMT) and carotid plaque morphology in patients receiving multifactorial cardiovascular disease (CVD) risk factor management in a community-based prevention clinic. Quantitative changes in CIMT and qualitative changes in carotid plaque morphology may be measured non-invasively by ultrasound.

MATERIAL AND METHODS

This is a retrospective study on a cohort of 324 patients who received multifactorial cardiovascular risk reduction treatment at a community prevention clinic. All patients received lipid-lowering medications (statin, niacin, and/or ezetimibe) and lifestyle modification. All patients underwent at least one follow-up CIMT measurement after starting their regimen. Annual biomarker, CIMT, and plaque measurements were analyzed for associations with CVD risk reduction treatment.

RESULTS

Median time to last CIMT was 3.0 years. Compared to baseline, follow-up analysis of all treatment groups at 2 years showed a 52.7% decrease in max CIMT, a 3.0% decrease in mean CIMT, and an 87.0% decrease in the difference between max and mean CIMT (p < 0.001). Plaque composition changes occurred, including a decrease in lipid-rich plaques of 78.4% within the first 2 years (p < 0.001). After the first 2 years, CIMT and lipid-rich plaques continued to decline at reduced rates.

CONCLUSION

In a cohort of patients receiving comprehensive CVD risk reduction therapy, delipidation of subclinical carotid plaque and reductions in CIMT predominantly occurred within 2 years, and correlated with changes in traditional biomarkers. These observations, generated from existing clinical data, provide unique insight into the longitudinal on-treatment changes in carotid plaque.

Particulate matter, the newborn methylome, and cardio-respiratory health outcomes in childhood

Ambient air pollution is associated with adverse health outcomes including cardio-respiratory diseases. Epigenetic mechanisms such as DNA methylation may play a role in driving such associations. We investigated the effects of prenatal particulate matter (PM) exposure on DNA methylation of 178,309 promoter regions in 240 newborns using the Infinium HumanMethylation450 BeadChip, using a generalized linear regression model with a quasi-binomial link family, adjusted for gender, plate, and cell types. PM-associated CpG loci were then investigated for their associations with childhood asthma, carotid intima-media thickness (CIMT), and blood pressure (BP) using logistic or linear regression. Thirty-one loci were associated with either PM₁₀ or PM_2.5 using FDR-corrected p-values of less than 0.15. Two loci were evaluated for replication in a separate population of 280 Children's Health Study (CHS) subjects using Pyrosequencing, of which one successfully replicated (COLEC11 cg03579365). Three of the 31 loci were also associated with physician-diagnosed asthma at 6 years old, two were associated with CIMT and one with systolic BP at 10 years old. A higher methylation level in TM9SF2 (cg02015529) and UBE2S (cg00035623), respectively, was associated with a 2SD increase in prenatal PM and was also associated with 36% and 98% increased odds of asthma; whereas methylation of TDRD6 (cg22329831) was negatively associated with PM and a 24% decreased odds of asthma. Prenatal PM exposure was associated with altered DNA methylation in newborn blood in a small number of gene promoters, some of which were also associated with cardio-respiratory health outcomes later in childhood. Keywords: methylation, particulate matter, air pollution, asthma, cardiovascular.

Vascular Effects of Early versus Late Postmenopausal Treatment with Estradiol

BACKGROUND

Data suggest that estrogen-containing hormone therapy is associated with beneficial effects with regard to cardiovascular disease when the therapy is initiated temporally close to menopause but not when it is initiated later. However, the hypothesis that the cardiovascular effects of postmenopausal hormone therapy vary with the timing of therapy initiation (the hormone-timing hypothesis) has not been tested.

METHODS

A total of 643 healthy postmenopausal women were stratified according to time since menopause (<6 years [early postmenopause] or ≥10 years [late postmenopause]) and were randomly assigned to receive either oral 17β-estradiol (1 mg per day, plus progesterone [45 mg] vaginal gel administered sequentially [i.e., once daily for 10 days of each 30-day cycle] for women with a uterus) or placebo (plus sequential placebo vaginal gel for women with a uterus). The primary outcome was the rate of change in carotid-artery intima-media thickness (CIMT), which was measured every 6 months. Secondary outcomes included an assessment of coronary atherosclerosis by cardiac computed tomography (CT), which was performed when participants completed the randomly assigned regimen.

RESULTS

After a median of 5 years, the effect of estradiol, with or without progesterone, on CIMT progression differed between the early and late postmenopause strata (P=0.007 for the interaction). Among women who were less than 6 years past menopause at the time of randomization, the mean CIMT increased by 0.0078 mm per year in the placebo group versus 0.0044 mm per year in the estradiol group (P=0.008). Among women who were 10 or more years past menopause at the time of randomization, the rates of CIMT progression in the placebo and estradiol groups were similar (0.0088 and 0.0100 mm per year, respectively; P=0.29). CT measures of coronary-artery calcium, total stenosis, and plaque did not differ significantly between the placebo group and the estradiol group in either postmenopause stratum.

CONCLUSIONS

Oral estradiol therapy was associated with less progression of subclinical atherosclerosis (measured as CIMT) than was placebo when therapy was initiated within 6 years after menopause but not when it was initiated 10 or more years after menopause. Estradiol had no significant effect on cardiac CT measures of atherosclerosis in either postmenopause stratum. (Funded by the National Institute on Aging, National Institutes of Health; ELITE ClinicalTrials.gov number, NCT00114517.).

Prenatal Air Pollution Exposure and Early Cardiovascular Phenotypes in Young Adults

Exposure to ambient air pollutants increases risk for adverse cardiovascular health outcomes in adults. We aimed to evaluate the contribution of prenatal air pollutant exposure to cardiovascular health, which has not been thoroughly evaluated. The Testing Responses on Youth (TROY) study consists of 768 college students recruited from the University of Southern California in 2007–2009. Participants attended one study visit during which blood pressure, heart rate and carotid artery arterial stiffness (CAS) and carotid artery intima-media thickness (CIMT) were assessed. Prenatal residential addresses were geocoded and used to assign prenatal and postnatal air pollutant exposure estimates using the U.S. Environmental Protection Agency’s Air Quality System (AQS) database. The associations between CAS, CIMT and air pollutants were assessed using linear regression analysis. Prenatal PM₁₀ and PM_2.5 exposures were associated with increased CAS. For example, a 2 SD increase in prenatal PM_2.5 was associated with CAS indices, including a 5% increase (β = 1.05, 95% CI 1.00–1.10) in carotid stiffness index beta, a 5% increase (β = 1.05, 95% CI 1.01–1.10) in Young’s elastic modulus and a 5% decrease (β = 0.95, 95% CI 0.91–0.99) in distensibility. Mutually adjusted models of pre- and postnatal PM_2.5 further suggested the prenatal exposure was most relevant exposure period for CAS. No associations were observed for CIMT. In conclusion, prenatal exposure to elevated air pollutants may increase carotid arterial stiffness in a young adult population of college students. Efforts aimed at limiting prenatal exposures are important public health goals.

Methods and baseline cardiovascular data from the Early versus Late Intervention Trial with Estradiol testing the menopausal hormone timing hypothesis

OBJECTIVE

This study aims to present methods and baseline data from the Early versus Late Intervention Trial with Estradiol (ELITE), the only clinical trial designed to specifically test the timing hypothesis of postmenopausal hormone therapy (HT). The timing hypothesis posits that HT effects depend on the temporal initiation of HT relative to time since menopause.

METHODS

ELITE is a randomized, double-blind, placebo-controlled trial with a 2 × 2 factorial design. Six hundred forty-three healthy postmenopausal women without cardiovascular disease were randomized to oral estradiol or placebo for up to 6 to 7 years according to time since menopause (<6 or ≥10 y). Carotid artery intima-media thickness (CIMT) and cardiac computed tomography were conducted to determine HT effects on subclinical atherosclerosis across menopause strata.

RESULTS

Participants in the early and late postmenopausal strata were well-separated by mean age (55.4 vs 65.4 y) and median time since menopause (3.5 vs 14.3 y). Expected risk factors (age, blood pressure, and body mass index) were associated with CIMT at baseline in both strata. In the early postmenopausal group, but not in the late postmenopausal group, we observed significant associations between CIMT and factors that may play a role in the responsiveness of atherosclerosis progression according to timing of HT initiation. These include low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, sex hormone-binding globulin, and serum total estradiol.

CONCLUSIONS

The ELITE randomized controlled trial is timely and unique. Baseline data indicate that ELITE is well-positioned to test the HT timing hypothesis in relation to atherosclerosis progression and coronary artery disease.

Edge-detected common carotid artery intima-media thickness and incident coronary heart disease in the multi-ethnic study of atherosclerosis

Background

Common carotid artery intima–media thickness (IMT) can be measured either by hand or with an automated edge detector. We performed a direct comparison of these 2 approaches and studied their respective associations with coronary heart disease outcomes.

Methods and Results

We studied 5468 participants of the Multi-Ethnic Study of Atherosclerosis, composed of white, Chinese, Hispanic, and black participants with an average age of 61.9 years (47.8% men) and who were free of coronary heart disease at baseline. Manual-traced and edge-detected IMT measurements were made in the same location on ultrasound images of the right common carotid artery far wall in an area free of plaque. Manual-traced and edge-detected common carotid artery IMT measurements were added separately to multivariable Cox proportional hazards models with time to incident coronary heart disease as the outcome and adjusted for traditional coronary heart disease Framingham risk factors, lipid-lowering therapy, blood pressure–lowering therapy, and race or ethnicity. Additional models were generated after adding clinic site and reader. There were 349 events during a median follow-up of 10.2 years. In adjusted models, the hazard ratio was not significant (1.31; 95% CI 0.84 to 2.06) for each millimeter increase in manual-traced IMT but was significant for edge-detected IMT (hazard ratio 1.63; 95% CI 1.12 to 2.37). Edge-detected IMT remained statistically associated with outcomes after additional adjustment for clinic site and reader performing the IMT measurement (hazard ratio 1.59; 95% CI 1.07 to 2.35).

Conclusions

Edge-detected common carotid artery far wall IMT has similar if not stronger associations with coronary heart disease outcomes when compared with manual-traced IMT.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov/. Unique identifier: NCT00063440.

Echolucency of the carotid artery intima-media complex and intima-media thickness have different cardiovascular risk factor relationships: the Women's Interagency HIV Study

Background

Adults infected with HIV have increased atherosclerosis potentially associated with both HIV and non‐HIV associated factors. We characterized risk factors for atherosclerosis as measured by noninvasive vascular imaging.

Methods and Results

We used B‐mode ultrasound to examine levels and correlates of echogenicity and vessel wall thickness of the carotid artery intima‐media complex in 1282 HIV‐infected and 510 HIV‐uninfected women of the Women's Interagency HIV Study. Levels of gray scale median (GSM, a measure of echogenicity) did not vary between HIV infection groups. In both groups, smokers had increased GSM, whereas age, diabetes, elevated blood pressure, and high BMI were associated with lower (rather than higher) GSM. Each of these non‐lipid CVD risk factors, especially age and blood pressure, was also associated with higher levels of carotid artery intima‐media thickness (cIMT). Higher serum triglyceride levels were associated with lower GSM in both HIV‐infected and HIV‐uninfected groups. Additional lipid risk factors for low GSM including high LDL cholesterol and low HDL cholesterol levels were identified in HIV uninfected but not in HIV infected women. In contrast to findings for GSM, among the lipid parameters only LDL cholesterol level had an association with cIMT, which was observed only in the HIV uninfected group.

Conclusions

Lipid and non‐lipid risk factor associations with echolucency of the carotid artery and the thickness of the common carotid artery intima‐media layer suggest that these measures capture different aspects of atherosclerosis.

The role of carotid intima-media thickness in predicting longitudinal cognitive function in an older adult cohort

BACKGROUND AND PURPOSE

Carotid atherosclerosis is a risk factor for cerebrovascular disease in older adults. Although age-related cognitive decline has been associated with cerebrovascular disease, not much is known about the consequences of carotid atherosclerosis on longitudinal cognitive function. This study examines the longitudinal relationship between atherosclerosis and cognition in a sample of non-demented older subjects using baseline measurements of carotid intima media thickness (CIMT) and annual cognitive measures of executive function (EXEC) and verbal memory (MEM).

METHODS

Baseline measurements included CIMT derived from B-mode carotid artery ultrasound, structural T1-weighted images of white matter hypointensities (WMH), white matter lesions (WML), and cerebral infarct. Hypertension, low-density lipoprotein (LDL), diabetes, and waist to hip ratios (WHR) were included as covariates in our models to control for cerebrovascular risks and central adiposity. Annual composite scores of EXEC and MEM functions were derived from item response theory. Linear mixed models were used to model longitudinal cognitive change.

RESULTS

A significant inverse relationship was found between baseline CIMT and annual EXEC score, but not annual MEM score. Subjects included in the highest 4th quartile of CIMT showed a rate of annual decline in EXEC score that was significant relative to subjects in lower quartile groups (p<0.01). The relationship between the 4th quartile of CIMT and annual EXEC score remained significant after independently adjusting for imaging measures of white matter injury and cerebral infarct.

CONCLUSIONS

Older adult subjects with the highest index of CIMT showed an annual decline in EXEC scores that was significant relative to subjects with lower quartile measurements of CIMT, independent of our measures of white matter injury and cerebral infarct. Our findings suggest that elevated measures of CIMT may mark an atherosclerotic state, resulting in a decline in executive function and not memory in non-demented older adults.

Predictors of subclinical atherosclerosis in women with spinal cord injury

BACKGROUND

Chronic spinal cord injury (SCI) is associated with an increase in risk factors for cardiovascular disease (CVD). In the general population, atherosclerosis in women occurs later than in men and usually presents differently. Associations between risk factors and incidence of CVD have not been studied in women with SCI.

OBJECTIVE

To determine which risk factors for CVD are associated with increased carotid intima-media thickness (CIMT), a common indicator of atherosclerosis, in women with SCI.

METHODS

One hundred and twenty-two females older than 18 years with traumatic SCI at least 2 years prior to entering the study were evaluated. Participants were asymptomatic and without evidence of CVD. Exclusion criteria were acute illness, overt heart disease, diabetes, and treatment with cardiac drugs, lipid-lowering medication, or antidiabetic agents. Measures for all participants were age, race, smoking status, level and completeness of injury, duration of injury, body mass index, serum lipids, fasting glucose, hemoglobin A1c, and ultrasonographic measurements of CIMT. Hierarchical multiple linear regression was conducted to predict CIMT from demographic and physiologic variables.

RESULTS

Several variables were significantly correlated with CIMT during univariate analyses, including glucose, hemoglobin A1c, age, and race/ethnicity; but only age was significant in the hierarchical regression analysis.

CONCLUSIONS

Our data indicate the importance of CVD in women with SCI.

Simultaneous extraction of carotid artery intima-media interfaces in ultrasound images: assessment of wall thickness temporal variation during the cardiac cycle

OBJECTIVES

The aim of this work is to present and evaluate a novel segmentation method for localizing the contours of the intima-media complex in the carotid artery wall through longitudinal ultrasound B-mode imaging. The method is used to investigate the association between atherosclerosis risk factors and the cyclic variation of the intima-media thickness during the heart beat.

METHODS

The framework introduced is based on two main features. The first is a simultaneous extraction of both the lumen-intima and the media-adventitia interfaces, using the combination of an original shape-adapted filter bank and a specific dynamic programming scheme. The second is an innovative spatial transformation that eases the extraction of skewed and curved contours, and exploits the result from the previous image as a priori information, when processing the current image. The intima-media thickness is automatically derived from the estimated contours for each time step during the cardiac cycle. Our method was evaluated in vivo on 57 healthy volunteers and 25 patients at high cardiovascular risk. Reference contours were generated for each subject by averaging the tracings performed by three experienced observers.

RESULTS

Segmentation errors were 29 ± 27 μm for the lumen-intima interface, 42 ± 38 μm for the media-adventitia interface, and 22 ± 16 μm for the intima-media thickness. This uncertainty was similar to inter- and intra-observer variability. Furthermore, the amplitude of the temporal variation in thickness of the intima-media layers during the cardiac cycle was significantly higher in at-risk patients compared to healthy volunteers (79 ± 36 vs. 64 ± 26 μm, p = 0.032). Conclusion: The method proposed may provide a relevant diagnostic aid for atherosclerosis screening in clinical studies.

NOS1 methylation and carotid artery intima-media thickness in children

BACKGROUND

Nitric oxide (NO) plays an important role in cardiovascular health by maintaining and regulating vascular tone and blood flow. Epigenetic regulation of NO synthase (NOS), the genes responsible for NO production, may affect cardiovascular disease, including the development of atherosclerosis in children.

METHODS AND RESULTS

We measured percentage DNA methylation using bisulfite conversion and pyrosequencing assays on DNA from buccal cells provided by 377 participants of the Children's Health Study on whom carotid artery intima-media thickness (CIMT) measurements were also collected. We examined a total of 16 CpG loci located within NOS1, NOS2A, NOS3, ARG1, and ARG2 genes responsible for NO production. CIMT was measured using high-resolution B-mode carotid ultrasound. The association between percentage DNA methylation in ARG and NOS genes with CIMT was evaluated using linear regression adjusted for sex, ethnicity, body mass index, age at CIMT, town of residence, and experimental plate for pyrosequencing reactions. Differences in the association by ethnicity and ancestral group were also evaluated. For a 1% increase in average DNA methylation of NOS1, CIMT increased by 1.2 μm (P=0.02). This association was greater in Hispanic children of Native American descent (β=2.3; P=0.004) than in non-Hispanic whites (β=0.3; P=0.71) or Hispanic whites (β=1.0; P=0.35).

CONCLUSIONS

DNA methylation of NOS1 has a plausible role in atherogenesis through regulation of NO production, although ancestry may alter the magnitude of this association.

HDL anti-oxidant function associates with LDL level in young adults

OBJECTIVES

The primary objective was to evaluate predictors of HDL anti-oxidant function in young adults.

BACKGROUND

High-density lipoprotein (HDL) cholesterol is considered a protective factor for cardiovascular disease (CVD). However, increased levels are not always associated with decreased cardiovascular risk. A better understanding of the importance of HDL functionality and how it affects CVD risk is needed.

METHODS

Fifty non-Hispanic white subjects from the Testing Responses on Youth (TROY) study were randomly selected to investigate whether differences in HDL anti-oxidant function are associated with traditional cardiovascular risk factors, including carotid intima media thickness (CIMT), arterial stiffness and other inflammatory/metabolic parameters. HDL anti-oxidant capacity was evaluated by assessing its ability to inhibit low-density lipoprotein (LDL) cholesterol oxidation by air using a DCF-based fluorescent assay and expressed as a HDL oxidant index (HOI). The associations between HOI and other variables were assessed using both linear and logistic regression.

RESULTS

Eleven subjects (25%) had an HOI ≥ 1, indicating a pro-oxidant HDL. Age, LDL, high sensitivity C-reactive protein (hsCRP), and paraoxonase activity (PON1), but not HDL, were all associated with HOI level in univariate linear regression models. In multivariate models that mutually adjusted for these variables, LDL remained the strongest predictor of HOI (0.13 increase in HOI per 1 SD increase in LDL, 95% CI 0.04, 0.22). Atherogenic index of plasma, pulse pressure, homocysteine, glucose, insulin, CIMT and measurements of arterial stiffness were not associated with HOI in this population.

CONCLUSIONS

These results suggest LDL, hsCRP and DBP might predict HDL anti-oxidant function at an early age.

One, two and three-dimensional ultrasound measurements of carotid atherosclerosis before and after cardiac rehabilitation: preliminary results of a randomized controlled trial

Background

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.

Methods

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).

Results

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.

Conclusion

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.

Blunted nocturnal cortisol rise is associated with higher carotid artery intima-media thickness (CIMT) in overweight African American and Latino youth

BACKGROUND

Blunted diurnal cortisol variation has been associated with overt cardiovascular disease in adults. The relationship between the diurnal cortisol variation and subclinical atherosclerosis in youth has yet to be investigated. The objectives of this study were to (1) determine the relationship between overnight cortisol measures and CIMT in overweight and obese, African-American and Latino children; (2) assess ethnic differences in these relationships; and (3) explore whether overnight cortisol and CIMT relationships were independent of inflammatory markers, C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor-∝ (TNF-∝).

METHODS

One hundred fifty-six overweight and obese African-American and Latino children (ages 8-17, 86 M/70 F, 55 African-American/101 Latino) underwent measures of CIMT by B-mode ultrasound, nocturnal cortisol rise (NCR = salivary cortisol rise from 2200 h to awakening at 0530 h), cortisol awakening response (CAR = salivary cortisol from time of awakening to 30 min later), fasting serum cortisol and overnight urinary free cortisol.

RESULTS

Using linear regression, salivary cortisol(0530 h) and NCR were negatively associated with CIMT (β(standardized) = -0.215 and -0.220, p < 0.01) independent of age, height, percent body fat, ethnicity and systolic blood pressure. Nocturnal salivary cortisol(2200 h), morning serum cortisol, and overnight urinary free cortisol were not associated with CIMT. Using ANCOVA, participants with LOW NCR (NCR < 0.44 μg/dL, n = 52) had significantly greater CIMT than those with HIGH NCR (NCR ≥ 0.91 μg/dL, n = 52; 0.632 ± 0.008 vs. 0.603 ± 0.008 mm, p=0.01) after controlling for covariates. Ethnicity was independently associated with CIMT, whereby African-American children had greater CIMT than Latino children (-0.028 ± 0.009, p=0.006). The relationships between cortisol measures and CIMT did not differ between the two ethnic groups (all p(interaction) = 0.28-0.97). CRP, IL-6 and TNF-∝ were not associated with CIMT (p > 0.05). IL-6 was inversely related to NCR (r = -0.186, p = 0.03), but it did not explain the relationship between NCR and CIMT.

CONCLUSIONS

Salivary cortisol(0530 h) and NCR, but not CAR, nocturnal salivary cortisol(2200 h), morning serum cortisol or overnight urinary free cortisol were associated with CIMT, independent of relevant covariates, including inflammatory factors. A low awakening salivary cortisol or a blunted NCR may be related to increased atherosclerosis risk in overweight and obese minority youth. These findings support adult studies suggesting flattened daytime diurnal cortisol variation impacts cardiovascular disease risk.

Serum carotenoids reduce progression of early atherosclerosis in the carotid artery wall among Eastern Finnish men

BACKGROUND

Several previous epidemiologic studies have shown that high blood levels of carotenoids may be protective against early atherosclerosis, but results have been inconsistent. We assessed the association between atherosclerotic progression, measured by intima-media thickness of the common carotid artery wall, and serum levels of carotenoids.

METHODS

We studied the effect of carotenoids on progression of early atherosclerosis in a population-based study. The association between concentrations of serum carotenoids, and intima-media thickness of the common carotid artery wall was explored in 840 middle-aged men (aged 46-65 years) from Eastern Finland. Ultrasonography of the common carotid arteries were performed at baseline and 7-year follow-up. Serum levels of carotenoids were analyzed at baseline. Changes in mean and maximum intima media thickness of carotid artery wall were related to baseline serum carotenoid levels in covariance analyses adjusted for covariates.

RESULTS

In a covariance analysis with adjustment for age, ultrasound sonographer, maximum intima media thickness, examination year, body mass index, systolic blood pressure, smoking, physical activity, serum LDL cholesterol, family history of coronary heart disease, antihypertensive medication and serum high sensitivity C-reactive protein, 7-year change in maximum intima media thickness was inversely associated with lycopene (p = 0.005), α-carotene (p = 0.002) and β-carotene (p = 0.019), respectively.

CONCLUSIONS

The present study shows that high serum concentrations of carotenoids may be protective against early atherosclerosis.

Birth weight and carotid artery intima-media thickness

OBJECTIVES

To determine the association between birth weight and carotid artery intima-media thickness (CIMT), a measure of atherogenesis, in a population of 11-year-old children.

STUDY DESIGN

CIMT measured by high-resolution ultrasound, and birth registry data were available for 670 children of the Southern California Children's Health Study. Multivariate regression analyses were performed to investigate the association between birth weight and CIMT, with adjustment for child's health status and lifestyle, pregnancy information, and parental health.

RESULTS

Mean CIMT was 0.57 mm (SD 0.04). We found a nonlinear association between birth weight and CIMT, with an increase in CIMT of 0.014 mm in the fifth (P value .01) compared with the third birth weight quintile. These associations were robust in subsample analyses in children considered normal-weight by gestational age or in term-born children. No significant association with CIMT was found for the lowest quintile.

CONCLUSIONS

Greater birth weight was significantly associated with increased CIMT at age 11 years. No evidence for an impact of lower birth weight was found. The predictive value of childhood CIMT on future cardiovascular outcomes is largely unknown, but strong associations between childhood cardiovascular disease risk factors and adult vascular disease suggest that increased CIMT in childhood may be clinically important.

Ultrasonographic measures of cardiovascular disease risk in antiretroviral treatment-naive individuals with HIV infection

OBJECTIVE

To evaluate associations between traditional cardiovascular disease (CVD) risk factors, inflammatory markers and markers of HIV disease activity with ultrasonographic measures of CVD risk in patients with HIV who are not receiving antiretroviral therapy (ART).

DESIGN

Cross-sectional, baseline evaluation of ART-naive HIV-infected individuals without known CVD or diabetes mellitus enrolled in a randomized ART treatment trial.

METHODS

Prior to ART initiation, carotid artery intima-media thickness (CIMT) and brachial artery flow-mediated dilation (FMD) were measured. Additional parameters included CD4 cell count, HIV viral load, body composition, lipoproteins and inflammatory markers. Associations with common CIMT, bifurcation CIMT, presence of carotid artery lesions and brachial artery FMD were evaluated.

RESULTS

The 331 enrolled individuals were a median (first-third quartile) of 36 (28-45) years old. Common and bifurcation CIMT values were higher and lesions more prevalent with older age (P < 0.001). FMD was lower with older age (P = 0.009). Those with a Framingham Risk Score of at least 6% per 10 years (N = 44) had higher common and bifurcation CIMT (P < 0.001), carotid lesion prevalence (P < 0.001) and lower FMD (P = 0.035). Independent associations with common CIMT were identified for increasing age, height, weight, small low-density lipoprotein (LDL) particles and black race; these were similar for bifurcation CIMT. Presence of carotid artery lesions was associated with increasing age, presence of metabolic syndrome, interleukin-6 and lower HIV-1 RNA.

CONCLUSION

In a contemporary cohort of ART-naive HIV-infected individuals, ultrasonographic measures of CVD risk were more strongly associated with traditional risk factors than CD4 cell counts, HIV replication or inflammatory markers.

Hemodynamically motivated choice of patch angioplasty for the performance of carotid endarterectomy

Patch angioplasty is the most common technique used for the performance of carotid endarterectomy. A large number of materials are available, but little is known to aid the surgeon in choosing a patch while caring for a patient with carotid disease. The objective of this study was to investigate biomechanics of the carotid artery (CA) repaired with patch angioplasty, study the influence of patch width and location of closure on hemodynamics, and to select the optimal patch material from those commonly used. For this purpose, a mathematical model was built that accounts for fluid-structure interaction, three-dimensional arterial geometry, non-linear anisotropic mechanical properties, non-Newtonian flow and in vivo boundary conditions. This model was used to study disease-related mechanical factors in the arterial wall and blood flow for different types of patch angioplasty. Analysis indicated that patch closures performed with autologous vein and bovine pericardium were hemodynamically superior to carotid endarterectomy with synthetic patch angioplasty (polytetrafluoroethylene, Dacron) in terms of restenosis potential. Width of the patch and location of arteriotomy were found to be of paramount importance, with narrow patches being superior to wide patches, and anterior arteriotomy being superior to the lateral arteriotomy. These data can aid vascular surgeons in their selection of patch angioplasty technique and material for the care of patients undergoing open CA repair.

Genetic polymorphisms associated with carotid artery intima-media thickness and coronary artery calcification in women of the Kronos Early Estrogen Prevention Study

Menopausal hormone treatment (MHT) may limit progression of cardiovascular disease (CVD) but poses a thrombosis risk. To test targeted candidate gene variation for association with subclinical CVD defined by carotid artery intima-media thickness (CIMT) and coronary artery calcification (CAC), 610 women participating in the Kronos Early Estrogen Prevention Study (KEEPS), a clinical trial of MHT to prevent progression of CVD, were genotyped for 13,229 single nucleotide polymorphisms (SNPs) within 764 genes from anticoagulant, procoagulant, fibrinolytic, or innate immunity pathways. According to linear regression, proportion of European ancestry correlated negatively, but age at enrollment and pulse pressure correlated positively with CIMT. Adjusting for these variables, two SNPs, one on chromosome 2 for MAP4K4 gene (rs2236935, β = 0.037, P value = 2.36 × 10(-06)) and one on chromosome 5 for IL5 gene (rs739318, β = 0.051, P value = 5.02 × 10(-05)), associated positively with CIMT; two SNPs on chromosome 17 for CCL5 (rs4796119, β = -0.043, P value = 3.59 × 10(-05); rs2291299, β = -0.032, P value = 5.59 × 10(-05)) correlated negatively with CIMT; only rs2236935 remained significant after correcting for multiple testing. Using logistic regression, when we adjusted for waist circumference, two SNPs (rs11465886, IRAK2, chromosome 3, OR = 3.91, P value = 1.10 × 10(-04); and rs17751769, SERPINA1, chromosome 14, OR = 1.96, P value = 2.42 × 10(-04)) associated positively with a CAC score of >0 Agatston unit; one SNP (rs630014, ABO, OR = 0.51, P value = 2.51 × 10(-04)) associated negatively; none remained significant after correcting for multiple testing. Whether these SNPs associate with CIMT and CAC in women randomized to MHT remains to be determined.

Self-reported menopausal symptoms, coronary artery calcification, and carotid intima-media thickness in recently menopausal women screened for the Kronos early estrogen prevention study (KEEPS)

OBJECTIVE

To determine whether self-reported menopausal symptoms are associated with measures of subclinical atherosclerosis.

DESIGN

Cross-sectional analysis.

SETTING

Multicenter, randomized controlled trial.

PATIENT(S)

Recently menopausal women (n = 868) screened for the Kronos Early Estrogen Prevention Study (KEEPS).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Baseline menopausal symptoms (hot flashes, dyspareunia, vaginal dryness, night sweats, palpitations, mood swings, depression, insomnia, irritability), serum E2 levels, and measures of atherosclerosis were assessed. Atherosclerosis was quantified using coronary artery calcium (CAC) Agatston scores (n = 771) and carotid intima-media thickness (CIMT). Logistic regression model of menopausal symptoms and E2 was used to predict CAC. Linear regression model of menopausal symptoms and E2 was used to predict CIMT. Correlation between length of time in menopause with menopausal symptoms, E2, CAC, and CIMT were assessed.

RESULT(S)

In early menopausal women screened for KEEPS, neither E2 nor climacteric symptoms predicted the extent of subclinical atherosclerosis. Palpitations and depression approached significance as predictors of CAC. Other symptoms of insomnia, irritability, dyspareunia, hot flashes, mood swings, night sweats, and vaginal dryness were not associated with CAC. Women with significantly elevated CAC scores were excluded from further participation in KEEPS; in women meeting inclusion criteria, neither baseline menopausal symptoms nor E2 predicted CIMT. Years since menopause onset correlated with CIMT, dyspareunia, vaginal dryness, and E2.

CONCLUSION(S)

Self-reported symptoms in recently menopausal women are not strong predictors of subclinical atherosclerosis. Continued follow-up of this population will be performed to determine whether baseline or persistent symptoms in the early menopause are associated with progression of cardiovascular disease.

CLINICAL TRIAL REGISTRATION NUMBER

NCT00154180.

Three-dimensional geometry of the human carotid artery

Accurate characterization of carotid artery geometry is vital to our understanding of the pathogenesis of atherosclerosis. Three-dimensional computer reconstructions based on medical imaging are now ubiquitous; however, mean carotid artery geometry has not yet been comprehensively characterized. The goal of this work was to build and study such geometry based on data from 16 male patients with severe carotid artery disease. Results of computerized tomography angiography were used to analyze the cross-sectional images implementing a semiautomated segmentation algorithm. Extracted data were used to reconstruct the mean three-dimensional geometry and to determine average values and variability of bifurcation and planarity angles, diameters and cross-sectional areas. Contrary to simplified carotid geometry typically depicted and used, our mean artery was tortuous exhibiting nonplanarity and complex curvature and torsion variations. The bifurcation angle was 36 deg ± 11 deg if measured using arterial centerlines and 15 deg ± 14 deg if measured between the walls of the carotid bifurcation branches. The average planarity angle was 11 deg ± 10 deg. Both bifurcation and planarity angles were substantially smaller than values reported in most studies. Cross sections were elliptical, with an average ratio of semimajor to semiminor axes of 1.2. The cross-sectional area increased twofold in the bulb compared to the proximal common, but then decreased 1.5-fold for the combined area of distal internal and external carotid artery. Inter-patient variability was substantial, especially in the bulb region; however, some common geometrical features were observed in most patients. Obtained quantitative data on the mean carotid artery geometry and its variability among patients with severe carotid artery disease can be used by biomedical engineers and biomechanics vascular modelers in their studies of carotid pathophysiology, and by endovascular device and materials manufacturers interested in the mean geometrical features of the artery to target the broad patient population.

Fully automated segmentation and tracking of the intima media thickness in ultrasound video sequences of the common carotid artery

The robust identification and measurement of the intima media thickness (IMT) has a high clinical relevance because it represents one of the most precise predictors used in the assessment of potential future cardiovascular events. To facilitate the analysis of arterial wall thickening in serial clinical investigations, in this paper we have developed a novel fully automatic algorithm for the segmentation, measurement, and tracking of the intima media complex (IMC) in B-mode ultrasound video sequences. The proposed algorithm entails a two-stage image analysis process that initially addresses the segmentation of the IMC in the first frame of the ultrasound video sequence using a model-based approach; in the second step, a novel customized tracking procedure is applied to robustly detect the IMC in the subsequent frames. For the video tracking procedure, we introduce a spatially coherent algorithm called adaptive normalized correlation that prevents the tracking process from converging to wrong arterial interfaces. This represents the main contribution of this paper and was developed to deal with inconsistencies in the appearance of the IMC over the cardiac cycle. The quantitative evaluation has been carried out on 40 ultrasound video sequences of the common carotid artery (CCA) by comparing the results returned by the developed algorithm with respect to ground truth data that has been manually annotated by clinical experts. The measured IMT(mean) ± standard deviation recorded by the proposed algorithm is 0.60 mm ± 0.10, with a mean coefficient of variation (CV) of 2.05%, whereas the corresponding result obtained for the manually annotated ground truth data is 0.60 mm ± 0.11 with a mean CV equal to 5.60%. The numerical results reported in this paper indicate that the proposed algorithm is able to correctly segment and track the IMC in ultrasound CCA video sequences, and we were encouraged by the stability of our technique when applied to data captured under different imaging conditions. Future clinical studies will focus on the evaluation of patients that are affected by advanced cardiovascular conditions such as focal thickening and arterial plaques.

Potential cardiovascular disease risk markers among HIV-infected women initiating antiretroviral treatment

BACKGROUND

Inflammation and hemostasis perturbation may be involved in vascular complications of HIV infection. We examined atherogenic biomarkers and subclinical atherosclerosis in HIV-infected adults before and after beginning highly active antiretroviral therapy (HAART).

METHODS

In the Women's Interagency HIV Study, 127 HIV-infected women studied pre and post HAART were matched to HIV-uninfected controls. Six semiannual measurements of soluble CD14, tumor necrosis factor (TNF) alfa, soluble interleukin (IL) 2 receptor, IL-6, IL-10, monocyte chemoattractant protein 1, D-dimer, and fibrinogen were obtained. Carotid artery intima-media thickness was measured by B-mode ultrasound.

RESULTS

Relative to HIV-uninfected controls, HAART-naive HIV-infected women had elevated levels of soluble CD14 (1945 vs 1662 ng/mL, Wilcoxon signed rank P < 0.0001), TNF-α (6.3 vs 3.4 pg/mL, P < 0.0001), soluble IL-2 receptor (1587 vs 949 pg/mL, P < 0.0001), IL-10 (3.3 vs 1.9 pg/mL, P < 0.0001), monocyte chemoattractant protein 1 (190 vs 163 pg/mL, P < 0.0001), and D-dimer (0.43 vs 0.31 μg/mL, P < 0.01). Elevated biomarker levels declined after HAART. Although most biomarkers normalized to HIV-uninfected levels, in women on effective HAART, TNF-α levels remained elevated compared with HIV-uninfected women (+0.8 pg/mL, P = 0.0002). Higher post-HAART levels of soluble IL-2 receptor (P = 0.02), IL-6 (P = 0.05), and D-dimer (P = 0.03) were associated with increased carotid artery intima-media thickness.

CONCLUSIONS

Untreated HIV infection is associated with abnormal hemostasis (eg, D-dimer), proatherogenic (eg, TNF-α), and antiatherogenic (eg, IL-10) inflammatory markers. HAART reduces most inflammatory mediators to HIV-uninfected levels. Increased inflammation and hemostasis are associated with subclinical atherosclerosis in recently treated women. These findings have potential implications for long-term risk of cardiovascular disease in HIV-infected patients, even with effective therapy.

Vitamin D levels and markers of arterial dysfunction in HIV

HIV-infected patients have low vitamin D levels as well as an increase in cardiovascular (CVD) risk. We examined the relationship between vitamin D and three markers of arterial dysfunction among HIV-infected individuals on stable antiretroviral (ARV) therapy. Levels of 25-hydroxyvitamin D [25(OH)D] were assessed by chemiluminescent immunoassay (DiaSorin) in 100 enrollees into the Hawaii Aging with HIV-Cardiovascular Cohort Study, a cohort of HIV-infected subjects age ≥ 40 years on stable (≥ 6 months) ARV therapy. The relationships between 25(OH)D levels and brachial artery flow-mediated dilation (FMD), right common carotid artery intima-media thickness (cIMT), and coronary artery calcium (CAC) were examined. Analytical methods included Pearson's correlations, Kruskal-Wallis tests, relative risks, and linear regression models. The cohort was 86% male and 60% white with a median age of 52 years and CD4 of 510 cells/mm(3). The median (Q1, Q3) level of 25(OH)D was 27.9 ng/ml (21.8, 38.3). There were 72 FMD, 50 cIMT, and 90 CAC measurements available for analyses. A significant correlation was observed between 25(OH)D levels and FMD (r=0.30, p=0.01) but not with cIMT (r=-0.05, p=0.76). In a linear regression model, Framingham risk score attenuated the relationship between FMD and 25(OH)D. Those with lower 25(OH)D levels were at slightly higher risk of having CAC (RR=1.02, p=0.04). Among those with CAC, lower 25(OH)D levels were not associated with higher CAC scores (p=0.36). Lower vitamin D levels are associated with evidence of subclinical arterial dysfunction in HIV-infected individuals. The significance of these findings warrants further investigation.

Low free testosterone in HIV-infected men is not associated with subclinical cardiovascular disease

OBJECTIVES

Low testosterone (T) is associated with cardiovascular disease (CVD) and increased mortality in the general population; however, the impact of T on subclinical CVD in HIV disease is unknown. This study examined the relationships among free testosterone (FT), subclinical CVD, and HIV disease.

METHODS

This was a cross-sectional analysis in 322 HIV-uninfected and 534 HIV-infected men in the Multicenter AIDS Cohort Study. Main outcomes were coronary artery calcification presence, defined as a coronary artery calcium (CAC) score  >10 (CAC score was the geometric mean of the Agatston scores of two computed tomography replicates), and far wall common carotid intima-media thickness (IMT)/carotid lesion presence by B-mode ultrasound.

RESULTS

Compared with the HIV-uninfected men in our sample, HIV-infected men were younger, with lower body mass index (BMI) and more often Black. HIV-infected men had lower FT (age-adjusted FT 88.7 ng/dL vs. 101.7 ng/dL in HIV-uninfected men; P=0.0004); however, FT was not associated with CAC, log carotid IMT, or the presence of carotid lesions. HIV status was not associated with CAC presence or log carotid IMT, but was associated with carotid lesion presence (adjusted odds ratio 1.69; 95% confidence interval 1.06, 2.71) in HIV-infected men compared with HIV-uninfected men.

CONCLUSIONS

Compared with HIV-uninfected men, HIV-infected men had lower FT, as well as more prevalent carotid lesions. In both groups, FT was not associated with CAC presence, log carotid IMT, or carotid lesion presence, suggesting that FT does not influence subclinical CVD in this population of men with and at risk for HIV infection.

Cytomegalovirus immunoglobulin G antibody is associated with subclinical carotid artery disease among HIV-infected women

BACKGROUND

Cytomegalovirus (CMV) infection has been implicated in immune activation and accelerated progression of immunodeficiency from human immunodeficiency virus (HIV) coinfection. We hypothesized that CMV is associated with vascular disease in HIV-infected adults.

METHODS

In the Women's Interagency HIV Study, we studied 601 HIV-infected and 90 HIV-uninfected participants. We assessed the association of CMV immunoglobulin G (IgG) level with carotid artery intima-media thickness, carotid artery distensibility, Young's elastic modulus, and blood pressures. Multivariable models adjusted for age, race/ethnicity, smoking, diabetes, and body mass index.

RESULTS

Mean CMV IgG levels were higher in HIV-infected women compared with HIV-uninfected women (P < .01). Among HIV-infected women, higher CMV IgG level was associated with decreased carotid artery distensibility (P < .01) and increased Young's modulus (P = .02). Higher CMV IgG antibody level was associated with increased prevalence of carotid artery lesions among HIV-infected women who achieved HIV suppression on antiretroviral therapy, but not among viremic or untreated HIV-infected women. Adjustment for Epstein-Barr virus antibody levels and C-reactive protein levels had no effect on the associations between CMV IgG levels and vascular parameters.

CONCLUSIONS

Cytomegalovirus antibody titers are increased in HIV-infected women and associated with subclinical cardiovascular disease. Host responses to CMV may be abnormal in HIV infection and associated with clinical disease.