Metabolic syndrome increases carotid artery stiffness: the Northern Manhattan Study

The role of sirtuins and uncoupling proteins on vascular aging: The Northern Manhattan Study experience

Aging affects all organs. Arteries, in particular, are among the most affected. Vascular aging (VA) is defined as age-associated changes in function and structure of vessels. Classical VA phenotypes are carotid intima-media thickness (IMT), carotid plaque (CP), and arterial stiffness (STIFF). Individuals have different predisposition to these VA phenotypes and their associated risk of cardiovascular events. Some develop an early vascular aging (EVA), and others are protected and identified as having supernormal vascular aging (SUPERNOVA). The mechanisms leading to these phenotypes are not well understood. In the Northern Manhattan Study (NOMAS), we found genetic variants in the 7 Sirtuins (SIRT) and 5 Uncoupling Proteins (UCP) to be differently associated with risk to developing VA phenotypes. In this article, we review the results of genetic-epidemiology studies to better understand which of the single nucleotide polymorphisms (SNPs) in SIRT and UCP are responsible for both EVA and SUPERNOVA.

Detection of Early Vascular Atherosclerosis in Type 2 Diabetes Mellitus Using Ultrasound Radiofrequency-Data Technique

OBJECTIVES

To quantitatively evaluate changes in vascular elasticity and intima-media thickness (IMT) of the common carotid artery (CCA) with Ultrasound radiofrequency (RF)-data technology in asymptomatic patients with type-2 diabetes mellitus (T2DM) and controls.

MATERIALS AND METHODS

Thirty-seven T2DM patients and 39 controls were enrolled. Arterial elasticity and CCA-IMT were quantitatively assessed by RF-data technology. The CCA diameters in the diastolic and systolic phases, carotid distensibility (CD), IMT, values of stiffness (β) and local pulse wave velocity (PWVβ) were measured and compared between the two groups.

RESULTS

The T2DM group had significantly larger CCA diastolic and systolic diameter, lower CD values, higher IMT measurements (all p < 0.001), and higher values of β and PWVβ (all P < 0.05) than the controls. Significant differences were not revealed in the mean values of IMT, β, PWVβ and CD across both sides of the CCA (all P > 0.05).

CONCLUSIONS

Higher IMT measurement and lower arterial elasticity of the CCA are significantly pronounced in asymptomatic T2DM patients and may suggest atherosclerotic changes, and the ultrasound RF-data technique may be used as a potential approach for detection of early-stage atherosclerosis.

Is Stiffness Parameter β Useful for the Evaluation of Atherosclerosis?~ Its Clinical Implications, Limitations, and Future Perspectives ~

Atherosclerosis comprises two components, atherosis and sclerosis, characterized by morphological wall thickening and functional stiffening, respectively, of the arterial wall. In recent years, much interest has been directed to the role of functional changes in large arteries, i.e., increased stiffness or decreased elasticity, on the development of cardiovascular diseases. In fact, the clinical evaluation of arterial stiffness is increasingly performed in patients with cardiovascular risk factors. Local arterial stiffness is measured using an ultrasound technique implemented with an echo-tracking system at the common carotid and femoral arteries. Several indices of local arterial stiffness are obtained by ultrasound, among which stiffness parameter β is unique because it is the least affected by blood pressure at the time of measurement. Evidence from cross-sectional studies indicates that increased stiffness parameter β is associated with a number of cardiovascular risk factors, such as older age, smoking, insufficient physical activity, hypertension, obesity, metabolic syndrome, insulin resistance, type 2 diabetes, chronic kidney disease, and comorbid cardiovascular disease. Results from several prospective observational studies also suggest that carotid stiffness parameter β is a useful surrogate marker of cardiovascular events and/or mortality, although the results differ depending on the characteristics of the study subjects. Furthermore, several interventional studies have shown that carotid stiffness parameter β improved after lifestyle modification or drug treatment. In this review, we summarize the current evidence of stiffness parameter β of the carotid artery and discuss its clinical implications as a marker of vascular health or as a predictor of cardiovascular outcomes.

Mir-1, miR-122, miR-132, and miR-133 Are Related to Subclinical Aortic Atherosclerosis Associated with Metabolic Syndrome

Previously, miR-1, miR-122, miR-126, miR-132, miR-133, and miR-370 were found to be related to coronary artery disease (CAD) progression. However, their relationship with subclinical atherosclerosis, especially in subjects with metabolic syndrome, is unknown. Therefore, our aim was to determine their relationship with arterial markers of subclinical atherosclerosis. Metabolic syndrome subjects (n = 182) with high cardiovascular risk but without overt cardiovascular disease (CVD) were recruited from the Lithuanian High Cardiovascular Risk (LitHiR) primary prevention program. The ardio-ankle vascular index (CAVI), augmentation index normalized to a heart rate of 75 bpm (AIxHR75), aortic pulse wave velocity (AoPWV), and carotid artery stiffness were assessed. MicroRNAs (miRs) were analyzed in serum. Pearson correlation and a univariate linear regression t-test showed that miR-1, miR-133b, and miR-133a were negatively associated with CAVI mean, whereas miR-122 was positively associated. MiR-1, miR-133b and miR-133a, and miR-145 were negatively associated with AIxHR75. MiR-122 correlated negatively with AoPWV. In multivariate linear regression models, miR-133b and miR-122 predicted CAVImean, miR-133 predicted AIxHR75, and miR-122 predicted AoPWV. MiR-132 predicted right carotid artery stiffness, and miR-1 predicted left carotid artery stiffness. The addition of smoking to miR-133b and miR-122 enhanced the prediction of CAVI. Age and triglycerides enhanced the prediction of AoPWV by miR-122. A cluster of four miRs are related to subclinical atherosclerosis in subjects with metabolic syndrome. Combined, they may have a more substantial diagnostic or prognostic value than any single miR. Future follow-up studies are needed to establish their clinical relevance.

Type 2 Diabetes Mellitus Is Independently Associated With Decreased Neural Baroreflex Sensitivity: The Paris Prospective Study III

OBJECTIVE

Impaired baroreflex function is an early indicator of cardiovascular autonomic imbalance. Patients with type 2 diabetes mellitus (T2D) have decreased baroreflex sensitivity (BRS), however, whether the neural BRS (nBRS) and mechanical component of the BRS is altered in those with high metabolic risk (HMR, impaired fasting glucose and metabolic syndrome) or with overt T2D, is unknown. We examined this in a community-based observational study, the Paris Prospective Study III (PPS3). Approach and Results: In 7626 adults aged 50 to 75 years, resting nBRS (estimated by low-frequency gain, from carotid distension rate and RR [time elapsed between two successive R waves] intervals) and mechanical BRS were measured by high-precision carotid echotracking. The associations between overt T2D or HMR as compared with subjects with normal glucose metabolism and nBRS or mechanical BRS were quantified using multivariable linear regression analysis. There were 319 subjects with T2D (61±6 years, 77% male), 1450 subjects with HMR (60±6 years, 72% male), and 5857 subjects with normal glucose metabolism (59±6 years, 57% male). Compared with normal glucose metabolism, nBRS was significantly lower in HMR subjects (β=-0.07 [95% CI, -0.12 to -0.01]; P=0.029) and in subjects with T2D (β=-0.18 [95% CI, -0.29 to -0.07]; P=0.002) after adjustment for confounding and mediating factors. Subgroup analysis suggests significant and independent alteration in mechanical BRS only among HMR patients who had both impaired fasting glucose and metabolic syndrome.

CONCLUSIONS

In this community-based study of individuals aged 50 to 75, a graded decrease in nBRS was observed in HMR subjects and patients with overt T2D as compared with normal glucose metabolism subjects.

Carotid Artery Stiffness in Metabolic Syndrome: Sex Differences

INTRODUCTION

The effect of metabolic syndrome (MS) on carotid stiffness (CS) in the context of gender is under research.

OBJECTIVE

We examined the relationship between the MS and CS in men (M) and women (W) and investigated if the impact of cardiovascular risk factors on CS is modulated by gender.

PATIENTS AND METHODS

The study included 419 subjects (mean age 54.3 years): 215 (51%) with MS (109 W and 106 M) and 204 (49%) without MS (98 W and 106 M). Carotid intima-media thickness (IMT) and CS parameters (beta stiffness index (beta), Peterson's elastic modulus (Ep), arterial compliance (AC) and one-point pulse wave velocity (PWV-beta)) were measured with the echo-tracking (eT) system.

RESULTS

ANCOVA demonstrated that MS was associated with elevated CS indices (p = 0.003 for beta and 0.025 for PWV-beta), although further sex-specific analysis revealed that this relationship was significant only in W (p = 0.021 for beta). Age was associated with CS in both M and W, pulse pressure (PP) and body mass index turned out to be determinants of CS solely in W, while the effect of mean arterial pressure (MAP) and heart rate was more pronounced in M. MANOVA performed in subjects with MS revealed that age and diabetes mellitus type 2 were determinants of CS in both sexes, diastolic blood pressure and MAP - solely in M and systolic blood pressure, PP and waist circumference - solely in W (the relationship between the waist circumference and AC was paradoxical).

CONCLUSION

The relationship between MS and CS is stronger in W than in M. In subjects with MS, various components of arterial pressure exert different sex-specific effects on CS - with the impact of the pulsative component of arterial pressure (PP) observed in W and the impact of the steady component (MAP) observed in M.

Physical activity mitigates adverse effect of metabolic syndrome on vessels and brain

Metabolic syndrome (MetS) adversely affects the vasculature and cerebral white matter (CWM) integrity. Arterial stiffening has been associated with diminished CWM integrity. Physical activity (PA) can ameliorate components of MetS and subsequently affect arterial stiffening and CWM integrity. Our aim was to determine the role of PA on mitigating the adverse influence of MetS on arterial stiffness and CWM integrity. In a cross-sectional study design, sixty-six middle-aged adults (40-62 years) composed of 18 sedentary MetS (Sed MetS), 21 physically active MetS (Active MetS), and 27 healthy individuals absent of MetS risk factors were studied. Carotid artery stiffness was assessed via simultaneous ultrasound and tonometry. CWM integrity was measured using diffusion tensor imaging (DTI) through metrics of fractional anisotropy (FA) and mean diffusivity (MD). Carotid β-stiffness index in Active MetS was lower than Sed MetS but was not different from Healthy controls (6.6 ± 1.5, 7.7 ± 2.1, and 5.6 ± 1.6 au, p = 0.001). CWM integrity was significantly greater in Active MetS subjects compared to Sed MetS subjects but statistically equal to Healthy controls in the anterior limb of the internal capsule, and splenium of the corpus callosum, uncinate fasciculus, and superior corona radiata (all p < 0.05). Middle-aged individuals with MetS who habitually perform PA demonstrated lower arterial stiffness and more favorable CWM integrity than their sedentary peers, indicating that PA may be effective in mitigating the adverse effects of MetS on the vasculature and brain at midlife.

Association Between Carotid Artery Function and Structure in the Northern Manhattan Study

Background and purpose

Carotid plaque (CP), carotid intima media thickness (cIMT), and stiffness (STIFF) are pre-clinical markers of atherosclerosis and predictors of cerebrovascular disease (CVD). We sought to investigate whether STIFF is a significant determinant of cIMT and CP, which may provide an insight into the mechanism by which STIFF adds to the risk of CVD.

Methods

We analyzed 876 stroke-free subjects from the Northern Manhattan Study with available ultrasound measures. To obtain the associations with STIFF, we performed multivariable-adjusted regression, negative binomial regression (for CP number), and multinomial logistic regression (for plaque area).

Results

The mean age was 64 ± 9 years; 63% women and 65% Caribbean Hispanics. The mean cIMT was 0.93 ± 0.9 mm, the mean diastolic diameter 6.24 ± 0.94 mm, and STIFF 8.6 ± 6.2 ln mmHg. Prevalence of CP was 57%, and the mean total plaque area was 22.6 ± 23.0 mm². STIFF was positively associated with cIMT but not with CP. There was an association between diastolic diameter and thick plaque. For each millimeter increase in diastolic diameter, there was about a 20% increased risk of having thick plaque (vs. no plaque). In longitudinal analyses, each millimeter increase in diastolic diameter was associated with a 37% increased risk of incident plaque.

Conclusion

Increased STIFF was associated with increased cIMT and carotid artery dilatation with greater plaque burden. Increased cIMT and plaque burden represent vascular remodeling likely resulting from the two different age-related mechanisms, one that includes diffuse wall thickening (cIMT) with STIFF and another that incorporates focal atherosclerosis (plaque) with luminal dilatation.

Association of metabolic syndrome with carotid thickening and plaque in the general population: A meta-analysis

We performed a meta-analysis of population studies reporting data on carotid intima-media thickness and plaque in patients with and without metabolic syndrome (MetS) to provide a new piece of information on the relationship of MetS with both phenotypes of vascular damage. The Ovid MEDLINE, PubMed, and Cochrane CENTRAL databases were searched without time restriction up to December 31, 2016. Overall, 19 696 patients (22.2% with MetS) were included in eight studies. Common carotid intima-media thickness was greater in patients with MetS compared with those without it (788 ± 47 μm vs 727 ± 44 μm), with a standard means difference of 0.28 ± 0.06 (P = .00003). Increased intima-media thickness in patients with MetS was paralleled by a higher prevalence of plaques. The present meta-analysis shows that MetS is associated with both ultrasonographic phenotypes of carotid damage. This finding is consistent with the view of MetS as a cluster of hemodynamic and nonhemodynamic factors promoting vascular hypertrophy and plaque.

The prevalence of carotid plaque with different stability and its association with metabolic syndrome in China: The Asymptomatic Polyvascular Abnormalities Community study

Few studies have investigated the prevalence of carotid plaque with different stability in Chinese. As is well known, carotid atherosclerosis is tightly associated with metabolic syndrome (MetS); however, the data about the association between the presence of carotid plaque with different stability and MetS was limited. The aim of our study was to investigate the prevalence of carotid plaque with different stability and its potential association with MetS in general Chinese population.The Asymptomatic Polyvascular Abnormalities Community study is a community-based study to investigate the epidemiology of asymptomatic polyvascular abnormalities in Chinese adults. A total of 5393 participants were finally eligible and included in this study. The carotid plaque and its stability were assessed using ultrasonography. The MetS was defined using the criteria from US National Cholesterol Education Program-Adult Treatment Panel III. Data were analyzed with multivariate logistic regression models.Of the 5393 subjects, 1397 (25.9%) participants had stable carotid plaque, 1518 (28.1%) had unstable carotid plaque in participants, and 1456 (27.0%) had a MetS. MetS was, respectively, significantly associated with the prevalence of carotid plaque (odds ratio [OR]: 1.25; 95% confidence interval [CI]: 1.07, 1.47), stable carotid plaque (OR: 1.23; 95% CI: 1.02,1.48), and unstable carotid plaque (OR: 1.27; 95% CI: 1.03,1.56) after adjusting for age, gender, level of education, income, smoking, drinking, physical activity, body mass index, low-density lipoprotein, and high-sensitivity C-reactive protein. With the number of MetS components, the prevalence of carotid plaque, stable carotid plaque, and unstable carotid plaque significantly increased (P for trend <0.0001), respectively.In summary, the prevalence of carotid plaque was 54.1%, stable carotid plaque was 25.9%, and unstable carotid plaque was 28.1%. Our study revealed that the prevalence of carotid plaque, stable carotid plaque, and unstable carotid plaque was, respectively, significantly associated with MetS in the general population.

Higher Carotid Intima-Media Thickness in Subclinical Hypothyroidism Associated with the Metabolic Syndrome

BACKGROUND

The subclinical hypothyroidism (SH) and the metabolic syndrome (MS) have been associated with increased risk of atherosclerosis and cardiovascular disease (CVD). The measurement of carotid intima-media thickness (IMT) is capable of detecting early signs of atherosclerotic disease. The goal of the study was to compare the carotid IMT of patients with SH with and without the MS.

METHODS

Twenty-nine SH patients were subdivided into two groups: one with MS (SH + MS) and one without MS (SH - MS). The study also assessed a group of euthyroid patients (n = 31), also subdivided into two groups: one with MS (EU + MS) and one without MS (EU - MS). The clinical and laboratory data and the mean and maximum carotid IMT of the groups were compared.

RESULTS

Maximum (P = 0.012) and mean (P = 0.025) IMT were higher in the SH + MS group than in the SH-MS group. Maximum IMT was higher in the SH + MS group than in the EU + MS group (P = 0.048). Maximum IMT was positively correlated with fasting glucose (FG; R = 0.621; P < 0.01) and body mass index (R = 0.258; P = 0.041) and negatively correlated with low-density lipoprotein cholesterol (LDL-C) (R = -0.297; P = 0.017). Mean IMT was positively correlated with FG (R = 0.580; P < 0.01), systolic blood pressure (R = 0.292; P = 0.02), and triglycerides (R = 0.250; P = 0.048) and negatively correlated with LDL-C (R = -0.288; P = 0.022).

CONCLUSIONS

SH + MS patients have higher IMT than SH - MS or EU + MS patients, suggesting that SH may be one more CVD risk factor in patients with the MS.

Association between methylenetetrahydrofolate reductase (MTHFR) polymorphism and carotid intima medial thickness progression in post ischaemic stroke patient

BACKGROUND

Hyperhomocysteinemia is associated with an increased risk of atherosclerosis. The main cause of elevated levels of homocysteine is 677T allele, the gene encoded by methylenetetrahydrofolate reductase (MTHFR). Carotid atherosclerosis progression, which can be measured by examination of carotid intima-media thickness (C-IMT), is a predictor of recurrent ischemic stroke. The objective of this study was to determine a relationship between MTHFR polymorphism, homocysteine ​​levels, and increased C-IMT in post- ischemic stroke patients.

METHODS

This was an epidemiological prospective observational cohort study involving 71 patients with post-ischemic stroke subject of the first (onset 1 month) admitted in the Neurology Clinic of Kariadi Hospital during 2012 to 2013. C-IMT was examined using carotid duplex ultrasound at 1(st), 6(th), and 12(th) month after stroke onset. MTHFR gene polymorphism was examined using polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP). Homocysteine level was measured using Axis(®) Homocysteine EIA.

RESULTS

We found 3 categories of MTHFR gene variation, i.e., 677T/T, 677T/C, and 677C/C. The most frequent allele was MTHFR 677C (88.9%), while the MTHFR 677T allele frequency was 11.1%. The majority allele of the subject population was 677C/C, however, there were 3 subjects (4.2%) who had 677T/T allele. The 677T/T allele group had normal homocysteine level and the lowest mean C-IMT among others.

CONCLUSIONS

This study supports that the MTHFR 677T allele polymorphism is not associated with hyperhomocysteinemia as well as an increase in C-IMT in post ischemic stroke patients.

Carotid artery stiffness is related to hyperinsulinemia and insulin-resistance in middle-aged, non-diabetic hypertensive patients

BACKGROUND AND AIMS

Glycometabolic abnormalities are frequently found in hypertension and could affect the mechanical properties of carotid arteries. The aim of the study was to investigate the relationship of glucose tolerance, plasma insulin, and insulin sensitivity with carotid distensibility in middle-aged, non-diabetic hypertensive patients free of cardiac and vascular complications.

METHOD AND RESULTS

In 93 patients with grade 1-2, uncomplicated, primary hypertension and 68 matched normotensive controls we measured plasma glucose and insulin at fast and after an oral glucose load (OGTT), calculated the HOMA-index as a marker of insulin sensitivity, and assessed distensibility of common carotid arteries by B-mode ultrasonography. Hypertensive patients were hyperinsulinemic and insulin-resistant as compared to normotensive controls. Hypertensive patients with impaired fasting glucose and/or impaired glucose tolerance had comparable distensibility of carotid arteries. Patients with decreased carotid distensibility were older and had higher body mass, fasting and post-OGTT plasma insulin, HOMA-index, and carotid IMT than the remaining patients, but no differences in glycated hemoglobin, and fasting or post-OGTT plasma glucose. Carotid coefficient of distensibility was inversely related and β-stiffness directly related with fasting and post-OGTT plasma insulin, and HOMA-index. Multivariate logistic regression showed that age and post-OGTT plasma insulin levels predicted carotid artery stiffening independent of body mass index, sex, blood pressure, and plasma glucose levels.

CONCLUSIONS

The study demonstrates that decreased insulin sensitivity and the related hyperinsulinemia but not hyperglycemia could contribute to carotid artery stiffening in middle-aged, non-diabetic hypertensive patients free of cardiovascular complications.

Metabolic syndrome showed significant relationship with carotid atherosclerosis

Metabolic syndrome (MetS) is associated with an increased risk of cardiovascular disease. We assessed the associations between MetS and the indicators of carotid atherosclerosis as assessed by ultrasonography taking into consideration of confounders in the general population. A total of 1281 subjects (856 males, 425 females) were included in the present study. The total plaque score and maximum intima-media thickness (IMT) of the carotid arteries were measured as indicators of atherosclerosis. Cardiovascular risk factors were several metabolic components, serum uric acid, serum C-reactive protein (CRP), and lifestyle factors. MetS was defined according to the criteria of the National Cholesterol Education Program. The prevalences of an elevated total plaque score (≥5) and elevated IMT (>1 mm) of the carotid arteries were significantly higher in subjects with MetS as compared to subjects without MetS. Furthermore, a trend was observed towards higher prevalences of these indicators of atherosclerosis as the number of components of MetS increased. Logistic regression analysis revealed a significant association between elevated plaque score and MetS even after adjustments for age, serum uric acid, serum CRP and lifestyle factors in the males. Among the indicators of atherosclerosis assessed by carotid ultrasonography, a significant independent association was observed between the total plaque score and MetS in males in the general population.

Prevention and management of stroke in women

Stroke is the leading cause of acquired disability and the third leading cause of death in women worldwide. Sex differences in risk factors, treatment response and quality of life after stroke complicate stroke management in women. Women have an increased lifetime incidence of stroke compared to men, largely due to a sharp increase in stroke risk in older postmenopausal women. Women also have an increased lifetime prevalence of stroke risk factors, including hypertension and atrial fibrillation in postmenopausal women, as well as abdominal obesity and metabolic syndrome in middle-aged women. Controversy continues over the risks of oral contraceptives, hormone therapy and surgical intervention for carotid stenosis in women. Pregnancy and the postpartum period represent a time of increased risk, presenting challenges to stroke management. Recognition of these issues is critical to improving acute care and functional recovery after stroke in women.

Study of the effects of age and body mass index on the carotid wall vibration: Extraction methodology and analysis

This study aims to non-invasively extract the vibrations of the carotid wall and evaluate the changes in the carotid artery wall caused by age and obesity. Such evaluation can increase the possibility of detecting wall stiffness and atherosclerosis in its early stage. In this study, a novel method that uses a phase-tracking method based on the continuous wavelet transform calculates the carotid wall motion from the ultrasound radio frequency signals. To extract the high-frequency components of the wall motion, wall vibration, the empirical mode decomposition was then used. The posterior wall (intima-media) motion and vibration were extracted for 54 healthy volunteers (mean age: 33.87 ± 14.73 years), including 13 overweight subjects (body mass index > 25) and 14 female participants using their radio frequency signals. The results showed that the dominant frequency of the wall vibration correlates with age ( r = −0.5887, p < 0.001) and body mass index ( r = −0.4838, p < 0.001). The quantitative analysis further demonstrated that the dominant frequency of the vibration in the radial direction of the carotid wall decreases by age and is lower in overweight subjects. Besides, the peak-to-peak amplitude of the wall vibration showed significant correlations with age ( r = −0.5456, p < 0.001) and body mass index ( r = −0.5821, p < 0.001). The peak-to-peak amplitude also decreases by age and is lower in overweight subjects. However, there were no significant correlations between these features of the wall vibrations and systolic/diastolic blood pressure and sex. Our proposed measures were certified using the calculated arterial stiffness indices. The average power spectrum of the elderly subjects’ wall motion in the frequency range of the wall vibration (>100 Hz) is decreased more in comparison with the young subjects. Our results revealed that the proposed method may be useful for detecting the stiffness and distortion in the carotid wall that occur prior to wall thickening caused by age as an early-stage atherosclerotic sign.

Can metabolic syndrome presence predict carotid intima-media thickness?

The aim of this investigation was to analyze metabolic syndrome (MS) impact on carotid intima-media thickness (cIMT). Prospective study of 300 patients with suspected coronary artery disease admitted for an elective coronary angiography were evaluated. Patients with previously known cardiac disease were excluded. In the population, 23.0% were diabetics and 40.5% had MS (but no diabetes). cIMT was not significantly different in patients with MS, but was significantly higher in diabetic patients compared with MS and control patients. Independent predictors of cIMT were age, male gender, insulin, and high-density lipoprotein (HDL) cholesterol (the last one with an inverse association). In patients without MS, only age and HDL cholesterol were associated. In patients with MS, independent predictors were age, male gender, and glucose, and abdominal obesity showed an inverse relationship. In patients with stable angina, MS is not an independent predictor of cIMT. Nonmodifiable variables (age and gender) are the most important determinants of cIMT, as well as blood glucose, in MS patients. Abdominal obesity was protective. J Clin Hypertens (Greenwich). 2012;00:00-00. ©2012 Wiley Periodicals, Inc.

Central versus peripheral cardiovascular risk in metabolic syndrome

Individuals with metabolic syndrome (MetS; i.e., three of five of the following risk factors (RFs): elevated blood pressure, waist circumference, triglycerides, blood glucose, or reduced HDL) are thought to be prone to serious cardiovascular disease and there is debate as to whether the disease begins in the peripheral vasculature or centrally. This study investigates hemodynamics, cardiac function/morphology, and mechanical properties of the central (heart, carotid artery) or peripheral [total peripheral resistance (TPR), forearm vascular bed] vasculature in individuals without (1–2 RFs: n = 28), or with (≥3 RFs: n = 46) MetS. After adjustments for statin and blood pressure medication use, those with MetS had lower mitral valve E/A ratios (<3 RFs: 1.24 ± 0.07; ≥3 RFs: 1.01 ± 0.04; P = 0.025), and higher TPR index (<3 RFs: 48 ± 2 mmHg/L/min/m²; ≥3 RFs: 53 ± 2 mmHg/L/min/m²; P = 0.04). There were no differences in heart size, carotid artery measurements, cardiovagal baroreflex, pulse-wave velocity, stroke volume index, or cardiac output index due to MetS after adjustments for statin and blood pressure medication use. The use of statins was associated with increased inertia in the brachial vascular bed, increased HbA1c and decreased LDL cholesterol. The independent use of anti-hypertensive medication was associated with decreased predicted VO2max, triglycerides, diastolic blood pressure, interventricular septum thickness, calculated left ventricle mass, left ventricle posterior wall thickness, and left ventricle pre-ejection period, but increased carotid stiffness, HDL cholesterol, and heart rate. These data imply that both a central cardiac effect and a peripheral effect of vascular resistance are expressed in MetS. These data also indicate that variance in between-group responses due to pharmacological treatments are important factors to consider in studying cardiovascular changes in these individuals.

Effects of dietary macronutrient distribution on vascular integrity in obesity and metabolic syndrome

Metabolic syndrome is a condition characterized by a clustering of risk factors for cardiovascular disease. Emerging data suggest vascular integrity is disrupted in metabolic syndrome. Vascular integrity may be determined using several measurements, including pulse wave velocity, augmentation index, and flow-mediated dilation. Arterial stiffness has become an important clinical indicator of cardiovascular disease risk. Several circulating inflammatory peptides also impact vascular integrity. The present review examines the efficacy of nutritional interventions aimed at improving vascular integrity and reducing levels of associated inflammatory peptides in individuals with metabolic syndrome, with a specific focus on the effect of dietary macronutrient redistribution on these factors.

Ethnic differences in carotid artery diameter and stiffness: the Northern Manhattan Study

OBJECTIVE

Race/ethnic differences in carotid arterial function and structure exist among those with cerebrovascular disease, but whether differences persist among healthy populations is unknown. Our objective was to investigate differences in carotid artery diameter and stiffness between race/ethnic groups, and examine whether these race/ethnic differences were age-dependent.

METHODS

Carotid diameters were assessed by B-mode ultrasound among 1536 participants from the Northern Manhattan Study (NOMAS), and carotid stiffness metrics were calculated. We used multivariable linear regression models to determine the relationship between race/ethnicity and both carotid arterial stiffness and carotid diastolic diameter.

RESULTS

Mean participant age was 70 ± 9 years (Hispanics = 68 ± 8, blacks = 72 ± 9, and whites = 74 ± 9, p < 0.0001). Mean DDIAM was 6.2 ± 1.0mm (Hispanics = 6.2 ± 0.9 mm, blacks = 6.3 ± 1.0 mm, and whites = 6.3 ± 1.0 mm, p < 0.005) and mean STIFF was 8.7 ± 6.3 (Hispanics = 8.5 ± 5.7, blacks = 9.2 ± 6.2 and whites = 8.9 ± 6.9, p < 0.02). In a model that adjusted for sociodemographics and vascular risk factors including hypertension, diabetes, dislipidemia, renal function, physical acticity and a history of known coronary artery diseases; age was positively associated with greater DDIAM in Hispanics (p < 0.0001) but not among blacks or whites. Older age was associated with greater stiffness among Hispanics (p < 0.0001) and blacks (p < 0.003), but not among whites.

CONCLUSIONS

We found race/ethnic differences in the association between age and arterial stiffness and diameter, including age-dependent arterial dilation observed in Hispanics that was not observed among blacks or whites.