Pulse wave velocity and augmentation index, but not intima-media thickness, are early indicators of vascular damage in hypercholesterolemic children

Arterial Compliance Measurement in Overweight and Hypertensive Children

OBJECTIVES

To investigate the pulse wave velocity (PWV) and augmentation index (Alx), measures of arterial stiffness, in relation to hypertension and obesity, the main risk factors for cardiovascular diseases.

METHODS

Two groups of pediatric patients, 31 children and adolescents with hypertension and 85 with overweight, were analysed and compared to the control group (50 healthy individuals). Subjects were sampled by opportunity sampling at the Department of Pediatrics, Maribor. In each patient, blood pressure, anthropometrical parameters and PWV measurements using the applanation tonometry technique were performed.

RESULTS

There was a significant correlation between PWV and age (r = 0.461, p = 0.001) in the control group, whereas no correlation was obtained between PWV and body mass index (BMI) or central mean arterial pressure (CMAP). In the hypertensive group, PWV only correlated with CMAP (r = 0.496, p = 0.005). A significant correlation was found in the overweight group between PWV and both age and BMI (r = 0.484, p < 0.001 and r = 0.347, p = 0.001, respectively). Alx results were not taken into consideration.

CONCLUSIONS

The results of this pilot study show that overweight and hypertensive children and adolescents are associated with less compliant arteries than their healthy peers, which could be used for screening of patients with expected early cardiovascular risk.

Determinants of carotid-femoral pulse wave velocity in prepubertal children

BACKGROUND

Pulse wave velocity (PWV) is a noninvasive technique to evaluate arterial stiffness, a dynamic property of the vessels, reflecting their structure and function. Childhood obesity is associated with several cardiovascular comorbidities and to the progression of atherosclerosis. We aimed to compare carotid-femoral PWV between normal weight and overweight/obese prepubertal children and to quantify its association with other cardiovascular risk factors.

METHODS

Cross-sectional study of 315 children aged 8-9years. Anthropometrics, 24-h ambulatory blood pressure (BP) and carotid-femoral PWV were measured. Classification of obesity was according to World Health Organization (WHO) body mass index (BMI)-for-age reference values.

RESULTS

Compared to normal weight children, overweight and obese children presented significantly higher levels of PWV (4.95 (P25-P75: 4.61-5.23), 5.00 (4.71-5.33), 5.10 (4.82-5.50) m/s, respectively; ptrend<0.001). Significant positive correlations were found between PWV and total cholesterol, LDL cholesterol, triglycerides, fasting insulin and insulin resistance levels (HOMA-IR) and with high-sensitivity C-reactive protein (hs-CRP). In a multivariate linear regression model adjusted for sex, age, height and 24-h systolic blood pressure z-score, the independent determinants of PWV were BMI, HOMA-IR and the absence of dipping.

CONCLUSIONS

The association between PWV and the loss of dipping and insulin resistance levels, independently of the BMI, reinforces the contribution of these comorbidities to vascular injury in early life.

Arterial stiffness and SBP variability in children and adolescents

BACKGROUND

The aim of this study was to explore the impact of ambulatory blood pressure (ABP) parameters on arterial stiffness measured by carotid-femoral pulse wave velocity (cf-PWV) in children and adolescents.

METHOD

The study population consisted of 138 consecutive young patients (age range 4-20 years) referred to our hypertension center. Office blood pressure (BP), 24-h ABP monitoring and cf-PWV measurements were performed in all patients. Family history and smoking habits were also recorded.

RESULTS

Among the study population, 10.6% had cf-PWV values equal to or higher than the 95th percentile of the study population. cf-PWV was higher in the hypertensive compared to the normotensive patients, classified by ABP levels even after adjustment for age and sex. Significant correlations were found between cf-PWV and age, weight, height, estimated central pulse pressure (PP), office SBP and DBP, and ABP parameters including 24-h SBP and DBP, weighted 24-h SBP variability, 24-h SBP and DBP load, 24-h mean arterial pressure (MAP), daytime and night-time SBP, daytime and night-time SBP variability, but not with office and 24-h heart rate, 24-h heart rate variability, 24-h daytime and night-time PP, DBP variability, ambulatory arterial stiffeness index and BMI z-score. In analysis of covariance, only weighted 24-h SBP variability (β = 0.28, P < 0.05) and daytime SBP variability (β = 0.15, P < 0.05) were the independent determinants of cf-PWV in children and adolescents.

CONCLUSION

These data may suggest that increased SBP variability is closely associated with arterial stiffness in children and adolescents.

Hypercholesterolemia and Hypertension: Two Sides of the Same Coin

The aim of this review article is to summarize the current knowledge about mechanisms that connect blood pressure regulation and hypercholesterolemia, the mutual interaction between hypertension and hypercholesterolemia, and their influence on atherosclerosis development. Our research shows that at least one-third of the population of Western Europe has hypertension and hypercholesterolemia. Several biohumoral mechanisms could explain the relationship between hypertension and hypercholesterolemia and the association between these risk factors and accelerated atherosclerosis. The most investigated mechanisms are the renin-angiotensin-aldosterone system, oxidative stress, endothelial dysfunction, and increased production of endothelin-1. Arterial hypertension is frequently observed in combination with hypercholesterolemia, and this is related to accelerated atherosclerosis. Understanding the mechanisms behind this relationship could help explain the benefits of therapy that simultaneously reduce blood pressure and cholesterol levels.

Objectively measured physical activity and sedentary-time are associated with arterial stiffness in Brazilian young adults

OBJECTIVE

To examine the associations between objectively measured physical activity and sedentary time with pulse wave velocity (PWV) in Brazilian young adults.

METHODS

Cross-sectional analysis with participants of the 1982 Pelotas (Brazil) Birth Cohort who were followed-up from birth to 30 years of age. Overall physical activity (PA) assessed as the average acceleration (mg), time spent in moderate-to-vigorous physical activity (MVPA - min/day) and sedentary time (min/day) were calculated from acceleration data. Carotid-femoral PWV (m/s) was assessed using a portable ultrasound. Systolic and diastolic blood pressure (SBP/DBP), waist circumference (WC) and body mass index (BMI) were analyzed as possible mediators. Multiple linear regression and g-computation formula were used in the analyses.

RESULTS

Complete data were available for 1241 individuals. PWV was significantly lower in the two highest quartiles of overall PA (0.26 m/s) compared with the lowest quartile. Participants in the highest quartile of sedentary time had 0.39 m/s higher PWV (95%CI: 0.20; 0.57) than those in the lowest quartile. Individuals achieving ≥30 min/day in MVPA had lower PWV (β = -0.35; 95%CI: -0.56; -0.14). Mutually adjusted analyses between MVPA and sedentary time and PWV changed the coefficients, although results from sedentary time remained more consistent. WC captured 44% of the association between MVPA and PWV. DBP explained 46% of the association between acceleration and PWV.

CONCLUSIONS

Physical activity was inversely related to PWV in young adults, whereas sedentary time was positively associated. Such associations were only partially mediated by WC and DBP.

Is Daytime Systolic Load an Important Risk Factor for Target Organ Damage in Pediatric Hypertension?

The aim of this study was to compare ambulatory blood pressure (BP) monitoring (ABPM) data and determine which hypertension type is a risk factor in target organ damage. A total of 82 children (47 boys) with suspected hypertension based on office BP measurements and considered hypertensive by ABPM were studied. Target organ damage included the following: 35.3% hypertensive retinopathy, 25.6% microalbuminuria, 15.8% increased left ventricular mass index, 29.2% increased carotid intima-media thickness (cIMT), 24.3% high augmentation index (AIx), and 19.5% high pulse wave velocity (PWV). The association between BP load, PWV, and cIMT was statistically significant. There were significant correlations between daytime systolic BP load, PWV, AIx, and cIMT. A statistically significant difference was also detected between nighttime systolic BP load, PWV, and cIMT values and nighttime diastolic BP load levels and values of AIx and cIMT. There was also a statistically significant difference between the high level of nighttime diastolic BP load and cIMT. The authors found that target organ damage was seen more often in children with primary hypertension who had systolic loads.

Influence of physical activity and gender on arterial function in type 2 diabetes, normal and impaired glucose tolerance

To determine whether Nordic walking improves cardiovascular function in middle-aged women and men, we included 121 with normal glucose tolerance, 33 with impaired glucose tolerance and 47 with Type 2 diabetes mellitus in a randomized controlled study. The intervention group added Nordic walking 5 h/week for 4 months to their ordinary activities. Aortic pulse wave velocity, aortic augmentation index, stiffness index, reflection index, intima-media thickness in the radial and carotid arteries, echogenicity of the carotid intima-media and systemic vascular resistance were measured. While baseline blood pressure did not differ by gender or diagnosis, aortic augmentation index was found to be higher in women in all groups. Vascular function was unchanged with intervention, without differences by gender or diagnosis. In conclusion, 4 months of Nordic walking is an insufficient stimulus to improve vascular function. Future studies should consider hard endpoints in addition to measures of vascular health, as well as larger population groups, long-term follow-up and documented compliance to exercise training.

Metabolomic study of carotid-femoral pulse-wave velocity in women

OBJECTIVE

Carotid-femoral pulse-wave velocity (PWV) is a measure of aortic stiffness that is strongly associated with increased risk of cardiovascular morbidity and mortality. The aim of the current study was to identify the molecular markers and the pathways involved in differences in PWV in women, in order to further understand the regulation of arterial stiffening.

METHODS

A total of 280 known metabolites were measured in 1797 female twins (age range: 18-84 years) not on any antihypertensive medication. Metabolites associated with PWV (after adjustment for age, BMI, metabolite batch, and family relatedness) were entered into a backward linear regression. Transcriptomic analyses were further performed on the top compounds identified.

RESULTS

Twelve metabolites were associated with PWV (P < 1.8 × 10). One of the most strongly associated metabolites was uridine, which was not associated with blood pressure (BP) and traditional risk factors but correlated significantly with the gene-expression levels of the purinergic receptor P2RY2 (Beta = -0.010, SE = 0.003, P = 0.007), suggesting that it may play a role in regulating endothelial nitric oxide synthase phosphorylation. On the other hand, phenylacetylglutamine was strongly associated with both PWV and BP.

CONCLUSION

Circulating levels of uridine, phenylacetylglutamine, and serine appear strongly correlated with PWV in women.

Arterial applanation tonometry: feasibility and reproducibility in children and adolescents

BACKGROUND

Aortic pulse wave velocity (PWV) and augmentation index (AIx) are markers of vascular health and have recently been used in pediatric clinical trials. However, there are limited data on standardization of these measurements in pediatrics. The objective of this study was to prospectively test the feasibility and reproducibility of PWV and AIx in children and adolescents.

METHODS

We performed arterial tonometry on 2 different days within 2 weeks in 40 healthy subjects aged 10-19 years. PWV and AIx were measured in triplicate on each visit.

RESULTS

The visits were separated by a mean of 3.08±3.7 days. We obtained PWV in 77 of 80 (96%) visits and AIx in 76 of 80 (95%) visits in triplicate. Intraclass correlation coefficients (ICCs) for PWV were 0.61 (95% confidence interval (CI) = 0-0.86) when at least 2 measurements and 0.92 (95% CI = 0-1) when 3 measurements were obtained at each visit that met the quality criteria established for adults by the manufacturer (n = 17 and 3 paired visits, respectively). For AIx, ICCs were 0.78 (95% CI = 0.58-0.88) and 0.81 (95% CI = 0.63-0.90) when measurements with an operator index ≥80, a measure of the quality of the waveform, were included (n = 39 and 36 paired visits, respectively).

CONCLUSIONS

Arterial applanation tonometry is feasible and reproducible in healthy children and adolescents. AIx has excellent intervisit reproducibility, whereas the intervisit reproducibility of PWV relies on acquisition of multiple measurements that meet quality criteria established for adults. These results have implications for the methodology of future pediatric clinical trials in a population at increasingly higher risk for premature atherosclerosis.

Arterial Stiffness in Children: Pediatric Measurement and Considerations

BACKGROUND

Arterial stiffness is a natural consequence of aging, accelerated in certain chronic conditions, and predictive of cardiovascular events in adults. Emerging research suggests the importance of arterial stiffness in pediatric populations.

METHODS

There are different indices of arterial stiffness. The present manuscript focuses on carotid-femoral pulse wave velocity and pulse wave analysis, although other methodologies are discussed. Also reviewed are specific measurement considerations for pediatric populations and the literature describing arterial stiffness in children with certain chronic conditions (primary hypertension, obesity, diabetes, chronic kidney disease, hypercholesterolemia, genetic syndromes involving vasculopathy, and solid organ transplant recipients).

CONCLUSIONS

The measurement of arterial stiffness in children is feasible and, under controlled conditions, can give accurate information about the underlying state of the arteries. This potentially adds valuable information about the functionality of the cardiovascular system in children with a variety of chronic diseases well beyond that of the brachial artery blood pressure.

A module of human peripheral blood mononuclear cell transcriptional network containing primitive and differentiation markers is related to specific cardiovascular health variables

Peripheral blood mononuclear cells (PBMCs), including rare circulating stem and progenitor cells (CSPCs), have important yet poorly understood roles in the maintenance and repair of blood vessels and perfused organs. Our hypothesis was that the identities and functions of CSPCs in cardiovascular health could be ascertained by analyzing the patterns of their co-expressed markers in unselected PBMC samples. Because gene microarrays had failed to detect many stem cell-associated genes, we performed quantitative real-time PCR to measure the expression of 45 primitive and tissue differentiation markers in PBMCs from healthy and hypertensive human subjects. We compared these expression levels to the subjects' demographic and cardiovascular risk factors, including vascular stiffness. The tested marker genes were expressed in all of samples and organized in hierarchical transcriptional network modules, constructed by a bottom-up approach. An index of gene expression in one of these modules (metagene), defined as the average standardized relative copy numbers of 15 pluripotency and cardiovascular differentiation markers, was negatively correlated (all p<0.03) with age (R² = −0.23), vascular stiffness (R² = −0.24), and central aortic pressure (R² = −0.19) and positively correlated with body mass index (R² = 0.72, in women). The co-expression of three neovascular markers was validated at the single-cell level using mRNA in situ hybridization and immunocytochemistry. The overall gene expression in this cardiovascular module was reduced by 72±22% in the patients compared with controls. However, the compactness of both modules was increased in the patients' samples, which was reflected in reduced dispersion of their nodes' degrees of connectivity, suggesting a more primitive character of the patients' CSPCs. In conclusion, our results show that the relationship between CSPCs and vascular function is encoded in modules of the PBMCs transcriptional network. Furthermore, the coordinated gene expression in these modules can be linked to cardiovascular risk factors and subclinical cardiovascular disease; thus, this measure may be useful for their diagnosis and prognosis.

MR pulse wave velocity increases with age faster in the thoracic aorta than in the abdominal aorta

PURPOSE

To assess the difference between thoracic and abdominal aortic pulse wave velocity (PWV) in apparently healthy subjects including young adults to elderly subjects.

MATERIALS AND METHODS

We performed PWV and distensibility measurements and analysis of thoracic and abdominal aortic segments in 96 apparently normal subjects aged 20-80 years with magnetic resonance (MR). Both unadjusted correlation and General Linear Model (GLM) analysis of log-transformed PWV (thoracic and abdominal aorta) and distensibility (four aortic cross-sections) were performed.

RESULTS

Both thoracic and abdominal PWV values and distensibility values increased with age. In unadjusted analyses the correlation between the ln(thoracic PWV) and age (r = 0.71; P < 0.001) was stronger than between ln(abdominal PWV) and age (r = 0.50; P < 0.001). In GLM analysis, the only determinant of thoracic and abdominal PWV was age (F = 42.5 and F = 14.8, respectively; both P < 0.001). Similarly, correlation between ln(distensibility) and age was strong (r = -0.79, r = -0.67, r = -0.71, and r = -0.65 for ascending, descending, diaphragmatic, and low abdominal aorta, respectively; all P < 0.001). In GLM analysis, age was the major determinant for distensibility of the ascending aorta (F = 81.7; P < 0.001), descending aorta (F = 42.2; P < 0.001), diaphragmatic aorta (F = 39.2; P < 0.001), and low abdominal aorta (F = 32.8; P < 0.001).

CONCLUSION

The thoracic aorta is less stiff than the abdominal aorta in young and middle-aged subjects, and stiffens more rapidly with age than the abdominal aorta, resulting in a stiffer thoracic than abdominal aorta at older age.

Circulating progenitor cells in hypertensive patients with different degrees of cardiovascular involvement

We investigated whether different degrees of hypertension-related cardiovascular involvement are associated with changes in circulating proangiogenic hematopoietic cell (PHC) numbers and/or phenotypes and/or in the PHC redox system in hypertensive individuals with isolated arterial stiffening (AS) hypertensives or with both carotid intima-media thickening and left ventricular hypertrophy (LVH) hypertensives. We also evaluated microRNA (miRs) 221 and 222 (miRs221/222) expression in CD34+ cells, the relationship between these miRs and cell number and reactive oxygen species (ROS) levels, and the expression of manganese superoxide dismutase (MnSOD), catalase (CAT) glutathione peroxidase type-1 (GPx-1) and gp91phox-containing nicotinamide-adenine-dinucleotide-phosphate-oxidase (NOX2). Proangiogenic hematopoietic cells (PHCs) from hypertensive patients and controls were isolated by flow cytometry. PHCs were higher in hypertensives than in controls but were lower in LVH than in AS hypertensives. In CD34+ cells from AS hypertensives, NOX2, MnSOD, CAT and GPx-1 were overexpressed; ROS, miRs and NOX2 were also increased and were associated with cell number. In LVH, we found an imbalance in the cell redox system; MnSOD showed the highest values, whereas CAT and GPx-1 were lower than in AS hypertensives. Intracellular ROS, miRs and NOX2 were higher and inversely associated with cell number. In AS hypertensives, the redox balance may sustain the increase in PHCs; by contrast, in hypertensives with more advanced lesions, redox imbalance may result in increased oxidative stress and cell reduction.

Endothelial dysfunction, but not structural atherosclerosis, is evident early in children with heterozygous familial hypercholesterolemia

Children with heterozygous familial hypercholesterolemia (heFH) are prone to premature atherosclerosis. Vascular endothelial dysfunction may predict increased cardiovascular risk in children with heFH. The aim of this study was to assess for early functional and structural vascular changes in children with heFH. This cross-sectional study included 30 children with heFH (mean age 12 years) and 30 age- and sex-matched controls. Brachial artery flow-mediated dilation (FMD), carotid intima-media thickness (cIMT), carotid-femoral pulse wave velocity, and large- and small vessel compliance were measured noninvasively. HeFH children exhibited significantly greater total and LDL cholesterol, apolipoprotein B, and lipoprotein (a) levels (p < 0.05 for all) and lower FMD (6.23 ± 3.88 vs. 9.46 ± 4.54 %, p < 0.004) compared with controls. When children were divided in age subgroups, FMD was found to be significantly decreased in heFH compared with control subjects only in ages >10 years (p < 0.05). However, FMD was found to be similarly impaired in heFH children in all age subgroups (two-way analysis of variance, p = 0.39). No differences in other vascular function indices were found. In heFH patients, but not in controls, FMD was inversely correlated with cIMT (r = -0.378, p = 0.036). In conclusion, endothelial dysfunction occurs early in heFH children indicating an increased risk for premature cardiovascular disease and reflecting probably the need for early initiation of anticholesterolemic treatment. Decreased FMD is detected before structural atherosclerotic changes occur.

Circulating progenitor cells in rheumatoid arthritis: association with inflammation and oxidative stress

OBJECTIVES

To evaluate the association between inflammation, oxidative stress, and circulating progenitor cell (CPC) number and redox equilibrium, vascular lesions and accelerated atherosclerosis in rheumatoid arthritis (RA).

METHOD

Circulating CD34+ cells were isolated from 33 RA patients and 33 controls. Reactive oxygen species (ROS) levels and mRNA expression of manganese superoxide dismutase (MnSOD), catalase (CAT), glutathione peroxidase type 1 (GPx-1) antioxidant enzymes, and the gp91phox-containing nicotinamide adenine dinucleotide phosphate (NADPH) oxidase NOX2 were measured in CD34+ cells. C-reactive protein (CRP), fibrinogen, erythrocyte sedimentation rate (ESR), carotid intima-media thickness (cIMT), and arterial stiffness (AS) were also evaluated. We investigated the relationships between inflammatory markers, vascular parameters, cell number, and antioxidant enzymes.

RESULTS

CD34+ cell number was lower in RA patients than in controls. In CD34+ cells from RA patients, ROS levels, MnSOD mRNA, and NOX2 mRNA were higher, while mRNA expression of GPx-1 and CAT was significantly lower. The AS, pulse wave velocity (PWV), and augmentation index (AIx) were higher, as was cIMT. CD34+ cell number was inversely correlated with CRP, ROS, PWV, and AIx, and with the CAT/MnSOD and GPx-1/MnSOD ratios. CRP was correlated with MnSOD mRNA, PWV, and AIx but not with CAT and GPx-1 mRNA.

CONCLUSIONS

Our data show a link between inflammation, oxidative stress, and the impairment of the antioxidant system of CPCs and their number, and with arterial stiffness in RA subjects. This could suggest a perspective on the accelerated development of vascular damage and atherosclerosis in RA.

Arterial stiffness changes in patients with cardiovascular risk factors but normal carotid intima-media thickness

AIMS

We aimed to evaluate, through an Echotracking system, the functional changes of carotid arteries with relation to the amount of cardiovascular risk factors in patients without structural atherosclerotic damage.

METHODS

From a series of 260 asymptomatic consecutive patients we selected 75 patients (mean age: 47 ± 8 years) with normal intima-media thickness (IMT) and without atherosclerotic plaques. In these patients, local arterial stiffness parameters were evaluated using a simple Echotracking system. Patients were divided in three groups: group 1 (n = 25 patients without risk factors), group 2 (n = 23 patients with one risk factor) and group 3 (n = 27 patients with two or more risk factors).

RESULTS

Carotid IMT was similar in all groups (P = ns). On the contrary, stiffness parameters progressively increased according to the number of risk factors [pulse wave velocity (PWV) = 5.8 ± 1.1 m/s, 6.4 ± 1.2 m/s and 6.7 ± 1.4 m/s in Group 1, 2 and 3, respectively, P = 0.002; β-index = 7.5 ± 3.4, 8.5 ± 3.2 and 9.5 ± 4.7 in Group 1, 2 and 3, respectively, P = 0.047]. Furthermore, on multivariate linear regression analysis, PWV and β-index significantly correlated (P = 0.002 and P = 0.048, respectively) with the number of risk factors even when adjusted for age, gender and current therapy.

CONCLUSION

In a population with normal carotid IMT and without plaques, changes in arterial stiffness are significantly related to the number of risk factors. This information could be relevant for a more tailored primary prevention in patients with risk factors even in absence of structural atherosclerotic abnormalities.

Local arterial stiffening assessed by MRI precedes atherosclerotic plaque formation

BACKGROUND

Atherosclerosis is known to impair vascular function and cause vascular stiffening. The aim of this study was to evaluate the potential predictive role of vascular stiffening in the early detection of atherosclerosis. Therefore, we investigated the time course of early functional and morphological alterations of the vessel wall in a murine atherosclerosis model. Because initial lesions are distributed inhomogeneously in early-stage atherosclerosis, MR microscopy was performed to measure vascular elasticity locally, specifically the local pulse wave velocity and the arterial wall thickness.

METHODS AND RESULTS

Local pulse wave velocity and the mean arterial wall thickness were determined in the ascending and the abdominal aortae of ApoE(-/-) and wild-type mice. In vivo MRI revealed that baseline pulse wave velocity and morphology were similar in 6-week-old ApoE(-/-) and WT mice, whereas at the age of 18 weeks, local pulse wave velocity was significantly elevated in ApoE(-/-) mice. Significantly increased vessel wall thickness was not found in ApoE(-/-) mice until the age of 30 weeks. Histological analysis of the aortae of ApoE(-/-) and WT mice showed that increased pulse wave velocity coincided with the fragmentation of the elastic laminae in the arterial wall, which is hypothesized to induce early vascular stiffening and may be promoted by macrophage-mediated matrix degradation.

CONCLUSIONS

We newly report that the assessment of local pulse wave velocity via MRI provides early information about the local progression of atherosclerosis before macroscopic alterations of the vessel wall occur.

Assessment of arterial stiffness using applanation tonometry

Augmentation index (AIx) and pulse wave velocity (PWV) assess functional and structural aspects of the vascular wall and are independent markers of cardiovascular morbidity and mortality. Like blood pressure, many factors, genetic, structural, and physiological, affect AIx and PWV. AIx and PWV can be assessed noninvasively using applanation tonometry. The technique is simple, but comes with a number of practical and technical limitations that have not been well documented and (or) explored. This review considers pulse wave analysis in the context of cardiovascular disease, and considers its limitations. Data are presented indicating that the placement of the probe is critical, and that the amplitude of the obtained signal is related to the variability in measurements. On a more theoretical note, issues are discussed regarding the applied transfer functions that are built in the devices to assess central AIx from peripheral waveforms. Altogether, PWV and its analysis are useful additions to the arsenal of parameters that can be used to assess vascular health and to estimate vascular risk. Yet, our analysis underscores the necessity for precise operating procedures, and calls for transparency regarding the applied transfer functions of commercial devices.

Calculating cardiac risk in obese adolescents before and after onset of lifestyle intervention

Prevalence and severity of obesity in adolescents is increasing worldwide. The obesity-associated cardiovascular risk factors (CRF) determine cardiac risk as demonstrated by longitudinal studies. Fat distribution and not overall fat mass determines the cardiac risk, since intra-abdominal adipose tissue is especially related to CRFs. Besides classical CRFs such as hypertension, dyslipidemia and impaired glucose metabolism, a proinflammatory and prothrombotic state in obesity is associated with cardiac risk. Adipocytokines such as adiponectin are related to cardiac risk and may present useful predictors of cardiac mortalities in future. Measurement of the carotid intima-media thickness is a new promising noninvasive marker for early cardiovascular changes including atherosclerosis. The therapy of choice to prevent cardiac events in obesity is lifestyle intervention of obese adolescents. However, in clinical practice, the weight loss in lifestyle interventions is only moderate and drug treatment of CRFs is seldom performed.

A randomized trial of fish oil omega-3 fatty acids on arterial health, inflammation, and metabolic syndrome in a young healthy population

Background

Long chain omega-3 fatty acids from fish oils (O3) are known to have beneficial effects on a number of vascular risk factors in at-risk populations. The effects of a highly bioavailable emulsified preparation on an overweight young adult population are less well known.

Methods

Young adults, age 18–30, with body mass indices (BMIs) greater than 23 (average = 28.1) were administered 1.7 g of O3 per day (N = 30) or safflower oil placebo (N = 27) in an emulsified preparation (Coromega, Inc.) for 4 weeks in a double-blind randomized design. Blood was drawn and anthropometric measurements taken before and after dosing. Hemodynamic measures (central pulse wave velocity, augmentation index, and aortic systolic blood pressure), inflammatory cytokines (IL-6, IL-8, IL-10, and tumor necrosis factor-α), red blood cell and plasma phospholipid fatty acid profiles, fasting serum lipids, glucose, and C-reactive protein were measured.

Results

Red cell and plasma phospholipid eicosapentaenoic acid and docosahexaenoic acid concentrations increased over the four weeks of dosing in the O3 group. Dosing with O3 did not affect central pulse wave velocity, augmentation index, or aortic systolic blood pressure. None of the five American Heart Association metabolic syndrome components improved over the dosing period. None of the inflammatory cytokines, C-reactive protein, or lipids (total or LDL cholesterol) improved over the dosing period.

Conclusions

No salutary effects of O3 were observed in hemodynamic, metabolic syndrome criteria or inflammatory markers as a result of this relatively short period of administration in this relatively overweight, but healthy young adult cohort.

Triglyceride to HDL-C ratio and increased arterial stiffness in children, adolescents, and young adults

BACKGROUND AND OBJECTIVE

Lipid levels are linked to early atherosclerosis. Risk stratification may be improved by using triglyceride to high-density lipoprotein cholesterol ratio (TG/HDL-C), which relates to arterial stiffness in adults. We tested whether TG/HDL-C was an independent predictor of arterial stiffness in youth.

METHODS

Subjects 10 to 26 years old (mean 18.9 years, 39% male, 56% non-Caucasian, n = 893) had laboratory, anthropometric, blood pressure, and arterial stiffness data collected (brachial distensibility, augmentation index, carotid-femoral pulse-wave velocity). Subjects were stratified into tertiles of TG/HDL-C (low, n = 227; mid, n = 288; high, n = 379).

RESULTS

There was a progressive rise in cardiovascular (CV) risk factors and arterial stiffness across TG/HDL-C ratio. The high TG/HDL-C ratio group had the stiffest vessels (all P < .03 by analysis of variance). TG/HDL-C as a continuous variable was an independent determinant of brachial distensibility in CV risk factor adjusted model and for carotid-femoral pulse-wave velocity in obese subjects, with trend for higher augmentation index.

CONCLUSIONS

TG/HDL-C, an estimate of small, dense low-density lipoprotein cholesterol, is an independent determinant of arterial stiffness in adolescents and young adults, especially in obese youth. These data suggest that use of TG/HDL-C may be helpful in identifying young adults requiring aggressive intervention to prevent atherosclerotic CV diseases.

The early cardiovascular changes in pediatric patients with systemic lupus erythematosus

BACKGROUND

In patients with systemic lupus erythematous (SLE) late-onset deaths are due to morbid cardiovascular changes (CVCs). Inflammatory and immune-mediated mechanisms are involved in promoting atherosclerosis development in SLE that is reflected in both functional and morphological changes in the cardiovascular system. The aim of our study was to determine the presence of these changes in pediatric SLE patients.

METHODS

Fifty-one consecutive patients (13 male, 38 female) with SLE and 25 healthy controls were included in the study. Arterial stiffness was assessed by carotid-femoral pulse wave velocity (PWVcf) and augmentation index (AIx), as measured by the Vicorder. Carotid intima-media thickness (cIMT) and the left ventricular mass index (LVMi) were also determined.

RESULTS

Patients with SLE, despite equivalent exposure to "traditional" cardiovascular risk factors, presented a higher mean PWVcf and AIx than controls (6.56 ± 1.45 vs. 5.29 ± 0.67 m/s, P =0.01 and 14.7 ± 8.1 vs. 9.36 ± 3.59 %, P = 0.02, respectively). SLE patients had greater values of cIMT and LVMi than controls (0.54 ± 0.06 vs. 0.35 ± 0.12 mm, P = 0.00 and 32.4 ± 10.8 vs 28.8 ± 1.5, P = 0.01, respectively). Nine patients had left ventricular hypertrophy (LVMi >38 g/m(2.7)). There was no significant difference in PWV, AIx, cIMT and LVMi values between presence of hypertension or nephritis within SLE patients. We found significant correlations between all parameters and activity scores.

CONCLUSIONS

Our results demonstrate that functional and morphological CVCs are independent of traditional risk factors in pediatric SLE patients and correlate with SLE disease activity scores in the early disease stages.

Assessments of arterial stiffness and endothelial function using pulse wave analysis

Conventionally, the assessments of endothelial function and arterial stiffness require different sets of equipment, making the inclusion of both tests impractical for clinical and epidemiological studies. Pulse wave analysis (PWA) provides useful information regarding the mechanical properties of the arterial tree and can also be used to assess endothelial function. PWA is a simple, valid, reliable, and inexpensive technique, offering great clinical and epidemiological potential. The current paper will outline how to measure arterial stiffness and endothelial function using this technique and include discussion of validity and reliability.

Management of familial hypercholesterolaemia in children and adolescents

Familial hypercholesterolaemia is a disorder of low-density lipoprotein (LDL) cholesterol metabolism, which is associated with the onset of vascular changes associated with coronary heart disease in childhood. This disorder has co-dominant transmission with a prevalence of one in 500 in the general population. Cascade screening is the most effective method of identifying children. Children in the at-risk group should have their cholesterol levels checked between the age of 2 and 10 years. Children with LDL cholesterol levels ≥ 3.4 mmol/L are likely to suffer from this disorder, although at this level there is a significant false positive rate. Molecular genetic testing is available for the LDL receptor gene, APOB gene and the PCSK9 gene. This is the most specific test for familial hypercholesterolaemia but has a false negative rate of 20-50%. Once diagnosed, treatment should be considered in children with an LDL cholesterol level ≥ 4.9 mmol/L. If the child has two other risk factors or a positive family history, this threshold should be lowered to ≥4.1 mmol/L. Guidelines recommend that treatment should be commenced by the age of 10 years, although some advise waiting until menarche in females. Statin therapy is currently recommended as first line treatment. Randomised placebo trials have shown that statin therapy reduces LDL cholesterol levels by 25% and is not associated with increased risk of adverse events. These are short-term studies, and longer follow-up will be required to definitively prove efficacy and safety.

Central blood pressures are associated with left ventricular mass index among African-American adolescents

BACKGROUND

There is a high burden of premature cardiovascular disease (CVD) among African Americans. Measures of central aortic blood pressure (CASP) and wave reflection are predictive of CVD risk in adults, but there is a paucity of data regarding the relation of these measures to target organ damage among adolescents. The objective of this study was to examine the relationship between CASP, central pulse pressure (CPP), and augmentation index (AI) with left ventricular mass index (LVMI).

METHODS

A cohort of 120 African-American adolescents was examined. Study participants underwent measurement of peripheral blood pressure (BP) using auscultation, pulse wave analysis (PWA) for determination of CASP, CPP, and AI, and echocardiography for determination of LVMI.

RESULTS

The cohort was 55% male, with mean BP 114/62 mm Hg, mean LVMI 36 g/m(2.7), mean CASP 94 mm Hg, mean CPP 31 mmHg, and mean AI was 0.5%. After adjustment for potential confounders, peripheral systolic BP (SBP) was significantly associated with LVMI (P = 0.008), but diastolic pressure was not (P = 0.887). The CASP and CPP were significantly associated with LVMI (P = 0.020 and 0.005, respectively). Peripheral SBP, CASP, and CPP had similar associations with respect to LVMI (r(2) = 0.26, 0. 26, and 0.27, respectively).

CONCLUSION

Central BP is associated with LVMI among African-American adolescents, and these associations are similar to those seen with peripheral BP measurements.

Fetoplacental vascular endothelial dysfunction as an early phenomenon in the programming of human adult diseases in subjects born from gestational diabetes mellitus or obesity in pregnancy

Gestational diabetes mellitus (GDM) and obesity in pregnancy (OP) are pathological conditions associated with placenta vascular dysfunction coursing with metabolic changes at the fetoplacental microvascular and macrovascular endothelium. These alterations are seen as abnormal expression and activity of the cationic amino acid transporters and endothelial nitric oxide synthase isoform, that is, the "endothelial L-arginine/nitric oxide signalling pathway." Several studies suggest that the endogenous nucleoside adenosine along with insulin, and potentially arginases, are factors involved in GDM-, but much less information regards their role in OP-associated placental vascular alterations. There is convincing evidence that GDM and OP prone placental endothelium to an "altered metabolic state" leading to fetal programming evidenced at birth, a phenomenon associated with future development of chronic diseases. In this paper it is suggested that this pathological state could be considered as a metabolic marker that could predict occurrence of diseases in adulthood, such as cardiovascular disease, obesity, diabetes mellitus (including gestational diabetes), and metabolic syndrome.

Association of serum lipids with arterial stiffness in a population-based study in Beijing

BACKGROUND

Some cardiovascular risk factors such as age, hypertension and diabetes have been confirmed to be positively correlated with arterial stiffness. However, the relationship between serum lipids and arterial stiffness is incompletely understood. Recent studies have been far from conclusive and consistent data were not obtained. We investigated the relationship between serum lipids and pulse wave velocity (PWV) in community-dwelling individuals in Beijing, China.

METHODS

This was a population-based, cross-sectional sample of adults (n = 2375; 48·1% men; age range, 40-96 years) from two communities in Beijing. A questionnaire was used for the risk factors of arterial stiffness. Anthropometry, blood pressure and heart rate were measured. Values of fasting plasma glucose (FPG), serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and uric acid were measured. Carotid-femoral PWV (cfPWV) and carotid-radial PWV (crPWV) were assessed non-invasively.

RESULTS

Carotid-femoral pulse wave velocity was significantly positively related to TC (r = 0·221; P < 0·0001), LDL-C (r = 0·193; P < 0·0001) and inversely related to HDL-C (r = -0·240; P < 0·0001), but not with TG (r = 0·073; P = 0·6721). crPWV was inversely related to HDL-C (r = -0·272; P < 0·0001), but not with TC (r = 0·007; P = 0·4781), LDL-C (r = 0·021; P = 0·6393) or TG (r = 0·008; P = 0·2498). The multiple regression analysis showed that LDL-C was independently associated with cfPWV and that HDL-C was inversely associated with cfPWV and crPWV. TC and TG were not independently related to cfPWV and crPWV.

CONCLUSIONS

These data show the correlation between some of the parameters of serum lipids and arterial stiffness. LDL-C was independently associated with aortic stiffness, and HDL-C was independently inversely associated with aortic stiffness and peripheral stiffness.

Feasibility of very-high resolution ultrasound to assess elastic and muscular arterial wall morphology in adolescents attending an outpatient clinic for obesity and lipid abnormalities

OBJECTIVE

Atherosclerosis begins during early life and is accelerated in individuals with cardiovascular risk factors. We hypothesized that very-high resolution ultrasound (VHRU, 25-55 MHz) could feasibly detect early arterial changes in adolescents with risk factors.

METHODS

We prospectively imaged the carotid, brachial and radial arterial morphology (far wall intima-media thickness, IMT; adventitia thickness, AT) by VHRU in 58 youths (age 14 ± 2 years) attending a Pediatric Preventive Cardiology Clinic for assessment and management of cardiovascular risk factors and compared the findings to those from an age-matched group of 67 controls.

RESULTS

Brachial and radial imaging was successful for all subjects. The carotid far wall could not be imaged in 7% of the patients due to limitations in penetration. VHRU image quality was related to body size and imaging depth. Imaging and analysis time were 12 ± 3 and 18 ± 3 min, respectively. Carotid IMT was increased in patients (0.42 ± 0.05 vs. 0.40 ± 0.06 mm, p = 0.05). No differences were found in brachial or radial IMT or AT vs. controls. Age, male gender, body mass index, systolic blood pressure (BP), but not lipid levels, were associated with arterial IMT in regression analyses.

CONCLUSION

VHRU is feasible in imaging carotid and peripheral muscular artery IMT in adolescents. The arterial IMT is associated with age, gender, adiposity and systolic BP, but not lipid levels, in this adolescent population. Further studies including patients with manifest clinical atherosclerosis are needed to assess if VHRU has applications in atherosclerosis research.

Short-term exposure to exogenous lipids in premature infants and long-term changes in aortic and cardiac function

OBJECTIVE

Intravenous lipid use is associated with an acute hyperlipidemia, but long-term consequences have not been studied. We investigated whether elevated lipids in humans during the critical period of preterm neonatal life have a long-term impact on aortic and myocardial function relevant to adult disease.

METHODS AND RESULTS

We followed up 102 subjects born prematurely and now aged 23 to 28 years. Eighteen received intravenous lipids as neonates and were matched to controls with equivalent perinatal characteristics. Global and regional aortic stiffness and left ventricular function were assessed by cardiovascular magnetic resonance. Those who received intravenous lipids had greater aortic stiffness in early adulthood (P=0.0002), with greater stiffness in the abdominal aorta (P=0.012). The relationship was graded according to the elevation in neonatal cholesterol induced by intravenous lipids (P<0.0001) but not other metabolic parameters altered by the infusion. Peak systolic circumferential strain was also reduced in the lipid group (P=0.006), which, again, was proportional to neonatal cholesterol level (P<0.01).

CONCLUSIONS

Aortic and myocardial function in young adulthood is associated with intralipid exposure during neonatal life for preterm infants, in a graded manner related to the rise in cholesterol. Circulating cholesterol during critical developmental periods may have long-term impacts on the human cardiovascular system.

Association of cardio-ankle vascular index with physical fitness and cognitive symptoms in aging Finnish firefighters

PURPOSE

Monitoring cardiovascular risk factors is important in health promotion among firefighters. The assessment of arterial stiffness (AS) may help to detect early signs of atherosclerosis. The aim of this study was to analyze associations between aerobic fitness, cognitive symptoms and cardio-ankle vascular index (CAVI) as a measure for AS among Finnish firefighters.

METHODS

The data are one part of a large 13-year follow-up study of the health and physical and mental capacity of Finnish professional firefighters. The subjects in this substudy comprised 65 male firefighters of a mean age of 48.0 (42-58) years in 2009. Their maximal oxygen uptake was successfully measured in two cross-sectional studies in 1996 and 2009, and they responded to questionnaires at both sessions, and their CAVI was measured in 2009. CAVI was calculated from the pulse waveform signal and pulse wave velocity. The lifestyle habits and subjective cognitive stress-related symptoms were collected via a standardized questionnaire. Muscular fitness was measured by the routine test battery used for Finnish firefighters.

RESULTS

CAVI was related to age. About one-fifth of the firefighters had a CAVI of >8. Aerobic fitness was the main physiological factor correlating with increased CAVI. Interestingly, VO(2)max and the accelerated decrease in VO(2)max during a 13-year follow-up were associated with signs of impaired vascular function. The cognitive symptoms derived from the Profile of Mood States questionnaire (POMS) were mainly associated with stress and sleeping difficulties. No clear association with physical fitness was found in this population of fit firefighters.

CONCLUSIONS

Among firefighters, the decrease in aerobic fitness predicts increased arterial stiffness. The speed of the age-related decline in maximal oxygen consumption is as important as absolute level. Against expectations, the cognitive function did not correlate with vascular health parameters. The cognitive symptoms, however, were only mild.

Modern ultrasound methods and atherosclerosis assessment in patients with familial hypercholesterolemia

Familial hypercholesterolemia (FHCH) is characterised by early atherosclerosis development and its fast progression. The prevalence of FHCH inRussiahas been increasing, therefore, it is important to evaluate the potential of various methods for atherosclerosis diagnostics. Arterial ultrasound is an informative, accessible, and safe method for evaluating atherosclerotic vascular changes. The modern ultrasound methods allow describing vascular wall status in detail, including qualitative and quantitative characteristics of its structure and function. At the same time, most ultrasound characteristics of arterial wall are used in research settings or are under development, and not implemented into clinical practice. The most promising parameters, applicable for clinical use in FHCH patients, simultaneously describe atherosclerosis severity and its localization, such as total plaque height, ankle-brachial index, and plaque number.

Circulating progenitor cells are increased in newly diagnosed untreated hypertensive patients with arterial stiffening but normal carotid intima-media thickness

Circulating progenitor cells (CPCs), including endothelial progenitor cells (EPCs), have a key role in endothelium repair. Cellular NADPH oxidase (Nox) enzymes, including Nox-containing gp91phox, represent a source of reactive oxygen species (ROS); ROS trigger protective signals but may also have detrimental effects. Cellular defenses against ROS include the enzymes manganese superoxide dismutase (MnSOD), catalase (CAT) and glutathione peroxidase type-1 (GPx-1). We investigated the relationships of CPCs with cellular gp91phox, MnSOD, CAT, GPx-1 and ROS levels and with carotid intima-media thickness (cIMT) and stiffness in hypertensives without additional risk factors for cardiovascular disease. CPCs from 53 newly diagnosed, untreated hypertensives and from 29 controls were isolated and identified by flow cytometry. gp91phox, MnSOD, CAT, and GPx-1 mRNA and protein expression and ROS generation were evaluated in enriched samples of CD34(+) cells; cIMT and stiffness were assessed. Hypertensives showed higher arterial stiffness (P < 0.001) but no difference in cIMT with respect to controls. ROS generation was slightly increased (P=0.04), whereas gp91phox, MnSOD, CAT and GPx-1 were significantly higher (P < 0.001) with respect to controls, as was CPC number (P < 0.001), but EPCs were no different. CPC and EPC numbers correlated with gp91phox, ROS and fibrinogen (P < 0.001); moreover, gp91phox, MnSOD, CAT and GPx-1 were correlated with CPC number. In early phases of arterial hypertension, before the development of wall thickening and even in the presence of arterial mechanical impairment, CPC number may be increased to maintain an adequate number of EPCs in peripheral blood.

A spontaneous, double-blind, double-dummy cross-over study on the effects of daily vardenafil on arterial stiffness in patients with vasculogenic erectile dysfunction

BACKGROUND

It is known that the incidence of endothelial dysfunction in patients with vascular erectile dysfunction (ED) is increased. The effects of daily vardenafil on endothelial function and arterial stiffness in patients with erectile dysfunction (ED) have never been investigated.

METHODS

20 men complaining vascular ED (mean IIEF5=12 ± 6 and peak systolic velocity-PSV=24 ± 2 cm/s) were enrolled in a 4-week, randomized, double-blind, double-dummy, crossover study (mean age 59 ± 11) and received either vardenafil 10mg daily or 20mg on-demand with a two-week washout interval. Primary endpoints were variation from baseline of reactive hyperemia (RH) and augmentation index (AI) calculated by fingertip peripheral arterial tonometry (PAT) device. Secondary endpoints were variations of IIEF-5 and SEP3 scores from baseline and plasma surrogate markers of endothelial function, i.e. endothelin-1 (ET-1) and adrenomedullin (ADM).

RESULTS

Patients who took daily vardenafil (vs. on-demand) reported significant (P<0.01) improvements in arterial stiffness as evaluated by AI and reduction of plasma ADM levels (p<0.05) but no improvement in average RH. When corrected for heart rate, ADM showed a strong direct relationship with AI (r(2)=0.22; p<0.005). The proportion of patients with an IIEF5 score of ≥ 22 or in SEP3 percentage of success rates were similar. Each treatment resulted in significantly greater IIEF5 scores (p<0.001) and better SEP3 response rates (p<0.0001) compared with baseline.

CONCLUSIONS

We demonstrated that daily vardenafil improves arterial stiffness and erectile function measurements in men with severe vasculogenic ED. This effect may be mediated, at least in part, by a reduction in ADM circulating levels.

Four-dimensional phase contrast magnetic resonance angiography: potential clinical applications

Unlike other magnetic resonance angiographic techniques, phase contrast imaging (PC-MRI) offers co-registered morphologic images and velocity data within a single acquisition. While the basic principle of PC-MRI dates back almost 3 decades, novel time-resolved three-dimensional PC-MRI (4D PC-MRI) approaches have become increasingly researched over the past years. So-called 4D PC-MRI includes three-directional velocity encoding in a three-dimensional imaging volume over time, thereby providing the opportunity to comprehensively analyze human hemodynamics in vivo. Moreover, its large volume coverage offers the option to study systemic hemodynamic effects. Additionally, this offers the possibility to re-visit flow in any location of interest without being limited to predetermined two-dimensional slices. The attention received for hemodynamic research is partially based on flow-based theories of atherogenesis and arterial remodeling. 4D PC-MRI can be used to calculate flow-related vessel wall parameters and may hence serve as a diagnostic tool in preemptive medicine. Furthermore, technical improvements including the availability of sufficient computing power, data storage capabilities, and optimized acceleration schemes for data acquisition as well as comprehensive image processing algorithms have largely facilitated recent research progresses. We will present an overview of the potential of this relatively young imaging paradigm. After acquisition and processing the data in morphological and phase difference images, various visualization strategies permit the qualitative analysis of hemodynamics. A multitude of quantitative parameters such as pulse wave velocities and estimates of wall shear stress which might serve as future biomarkers can be extracted. Thereby, exciting new opportunities for vascular imaging and diagnosis are available.