Abnormalities of vascular structure and function in pediatric hypertension

The Relationship between Selected Inflammation and Oxidative Stress Biomarkers and Carotid Intima-Media Thickness (IMT) Value in Youth with Type 1 Diabetes Co-Existing with Early Microvascular Complications

Recent years have confirmed the importance of oxidative stress and biomarkers of inflammation in estimating the risk of cardiovascular disease (CVD) and explaining not fully understood pathogenesis of diabetic macroangiopathy. We aimed to analyze the relation between the intima-media thickness (IMT) of common carotid arteries and the occurrence of classical cardiovascular risk factors, together with the newly proposed biomarkers of CVD risk (high-sensitivity C-reactive protein (hsCRP), myeloperoxidase (MPO), adiponectin, N-terminal-pro B-type natriuretic peptide (NT-proBNP) and vitamin D) in youth with type 1 diabetes (T1D) recognized in screening tests to present early stages of microvascular complications (VC). The study group consisted of 50 adolescents and young adults with T1D, mean age 17.1 years (10–26 age range), including 20 patients with VC (+) and 30 VC (−). The control group (Control) consisted of 22 healthy volunteers, mean age 16.5 years (11–26 age range). In the VC (+) patients, we found a significantly higher concentration of HbA1c, lipid levels, hsCRP and NT-proBNP. BMI and blood pressure values were highest in the VC (+) group. Higher levels of MPO and lower levels of vitamin D were found in both diabetic groups vs. Control. IMT in VC (+) patients was significantly higher and correlated positively with HbA1c, hsCRP, NT-pro-BNP and negatively with vitamin D levels. In conclusion, youth with T1D and VC (+) present many abnormalities in the classical and new CVD biomarkers. hsCRP and MPO seem to be the most important markers for estimating the risk of macroangiopathy. NT-proBNP may present a possible marker of early myocardial injury in this population.

Early Signs of Microvascular Endothelial Dysfunction in Adolescents with Newly Diagnosed Essential Hypertension

Endothelial dysfunction represents one of the key pathomechanisms in many diseases, including hypertension. Peripheral arterial tonometry (PAT) evaluates the functional status of microvascular endothelium and offers a biomarker of early, potentially reversible, vascular damage. This study aimed to assess endothelial function using conventional and novel indices of PAT in pediatric hypertensives. As such, 100 adolescents with normal blood pressure, and essential and white-coat hypertension were examined using EndoPAT 2000. Conventional reactive hyperemia index (RHI) and novel indices of hyperemic response, including the area under the curve of hyperemic response (AUC), were evaluated. AUC was the only parameter sensitive to the effect of hypertension, with significantly lower values in essential hypertensives compared to normotensives and white-coat hypertensives (p = 0.024, p = 0.032, respectively). AUC was the only parameter significantly correlating with mean ambulatory monitored blood pressure (r = −0.231, p = 0.021). AUC showed a significant negative association with age (p = 0.039), but a significant positive association with pubertal status indexed by plasma levels of dehydroepiandrosterone (p = 0.027). This is the first study reporting early signs of microvascular endothelial dysfunction evaluated using PAT in adolescents with newly diagnosed essential hypertension. Detailed analysis of hyperemic response using overall magnitude indexed by AUC provided a more robust method compared to the conventional evaluation of RHI.

Carotid Intima-Media Thickness Percentiles in Adolescence and Young Adulthood and Their Association With Obesity and Hypertensive Blood Pressure in a Population Cohort

BACKGROUND

This study aimed to derive carotid intima media thickness (CIMT) percentiles from a population-based sample of adolescents and young adults using improved technology, standardization and quality control, and to investigate the association of CIMT with hypertensive blood pressure (BP) and obesity.

METHODS

Four thousand seven hundred nine 14- to 28-year-old participants of the German KiGGS cohort 11-year follow-up, which was based on a nationwide population sample, had B-mode ultrasound CIMT measurement with semi-automated edge-detection and automatic ECG-gated real-time quality control. CIMT percentiles were estimated from far wall CIMT during 2 to 6 heart cycles using the GAMLSS statistical model. Hypertensive BP, overweight, obesity, and a risk score from added Z scores of triglycerides, total/HDL (high-density lipoprotein)-cholesterol ratio, and glycated hemoglobin were based on standardized measurements at baseline and follow-up.

RESULTS

CIMT differed by sex at all ages, furthermore by age and height in a nonlinear fashion. Percentiles were estimated simultaneously by age and height. Hypertensive BP and obesity were associated cross-sectionally and longitudinally with a higher risk of CIMT ≥75th percentile in log-binomial regression models adjusted for age, sex, height, current smoking, and cardiovascular risk score. For CIMT ≥90th percentile, the relative risk effect estimates were consistently >1 but often had large confidence intervals including 1, largest adjusted relative risk 3.37 (95% CI, 1.41-8.04) for the combination of hypertensive BP and obesity at follow-up.

CONCLUSIONS

Based on state-of-the-art measurements and statistical techniques, these population-based CIMT percentiles by sex, age and height add unbiased evidence for the association of subclinical atherosclerosis with hypertensive BP and obesity in the young.

Vascular Ageing in Youth: A Call to Action

Extensive evidence shows that risk factors for cardiovascular disease (CVD) begin to develop early in life. Childhood obesity and elevated blood pressure (BP) have become overwhelmingly challenging, with 57% of today's children predicted to be obese by the age of 35 years, and global rates of hypertension in children and adolescents increasing by 75% from 2000 to 2015. Thus, there is an urgent need for tools that can assess early CVD risk in youth, which may lead to better risk stratification, preventative intervention, and personalised medicine. Vascular ageing (the deterioration in vascular structure and function) is a pivotal progenitor of health degeneration associated with elevated BP. Exposure to adverse environmental and genetic factors from fetal life promotes the development and accumulation of subclinical vascular changes that direct an individual towards a trajectory of early vascular ageing (EVA)-an independent predictor of target organ damage in the heart, brain, and kidneys. Therefore, characterising vascular ageing from youth may provide a window into cardiovascular risk later in life. However, vascular ageing measurements only have value when techniques are accurate/validated and when reliable thresholds are available for defining normal ranges and ranges that signal increased risk of disease. The aim of this paper is to summarise current evidence on the importance of vascular ageing assessment in youth and the impact of interventions to prevent or delay EVA, to highlight the need for standardisation and validation of measurement techniques in children and adolescents, and the importance of establishing reference values for vascular ageing measures in this population.

Youth Vascular Consortium (YVC) Protocol: Establishing Reference Intervals for Vascular Ageing in Children, Adolescents and Young Adults

BACKGROUND

In the last two decades, the global prevalence of paediatric hypertension increased by approximately 75%. Nearly 25% of children are now classified as obese or overweight. Substantial evidence suggests that risk factors for cardiovascular disease (CVD) begin to develop in childhood, thus warranting the need for tools to better screen for early CVD risk in youth. Vascular ageing, the deterioration of vascular structure and function, may be a potentially useful tool for detecting the early and asymptomatic signs of CVD burden. However, it is currently unclear what differentiates normal from pathological ageing in youth as existing reference values for vascular ageing in youth are limited by small sample size or homogenous populations. The international Youth Vascular Consortium (YVC) has been established to address these issues.

AIMS

The primary aim of the YVC is to develop reference intervals of normal vascular ageing in children, adolescents, and young adults. The secondary, exploratory, aim is to perform head-to-head comparisons of vascular ageing biomarkers to determine which biomarker is most strongly related to cardiometabolic health.

STUDY DESIGN

The YVC is a retrospective, multicentre study and will collate data on vascular ageing in children (5-12 years), adolescents (13-18 years) and young adults (19-40 years), as well as routine clinical biochemistry, lifestyle, sociodemographic factors and parental health.

CONCLUSION

To date, 31 research groups from 19 countries have joined the YVC. To our knowledge, this will be the largest study of its kind to investigate vascular ageing in youth.

Aortic intima-media thickness in neonates exposed to early-onset preeclampsia

Aortic intima-media thickness (aIMT) and its ratio to aortic diameter (aIMT/AoD) were measured on the second and fifth postnatal day in 39 neonates exposed to early-onset preeclampsia and 39 controls. Both aIMT and aIMT/AoD were higher in neonates exposed to preeclampsia (P < 0.001 for all comparisons).

Progression to hypertension in youth and young adults with type 1 or type 2 diabetes: The SEARCH for Diabetes in Youth Study

Central obesity may contribute to the development of hypertension in youths with diabetes. The SEARCH for Diabetes in Youth Study followed 1518 youths with type 1 diabetes (T1D) and 177 with type 2 diabetes (T2D) diagnosed when <20 years of age for incident hypertension. Incident hypertension was defined as blood pressure ≥95th percentile (or ≥130/80 mm Hg) or reporting antihypertensive therapy among those without hypertension at baseline. Poisson regression models were stratified by diabetes type and included demographic and clinical factors, clinical site, and waist‐to‐height ratio (WHtR). Youths with T2D were more likely to develop hypertension than those with T1D (35.6% vs 14.8%, P < .0001). For each 0.01 unit of annual increase in WHtR, adjusted relative risk for hypertension was 1.53 (95% CI 1.36‐1.73) and 1.20 (95% CI 1.00‐1.43) for youths with T1D and T2D, respectively. Effective strategies targeted toward reducing central obesity may reduce hypertension among youths with diabetes.

Adiposity measures and their validity in estimating risk of hypertension in South Asian children: a cross-sectional study

OBJECTIVE

Given the South Asian phenotype of higher body fat at similar body mass index (BMI) relative to Caucasians, we sought to explore the association between prominent adiposity indicators with blood pressure (BP) and hypertension, to compare the accuracy of these indicators in estimating hypertension, and to provide cut-off values associated with adverse hypertension risk in South Asian children.

DESIGN

Cross-sectional study.

SETTING

Community-based recruitment in two Canadian cities (Hamilton and Surrey).

PARTICIPANTS

South Asian children (n=762) were recruited from two Canadian cities. Waist circumference, waist to height ratio and BMI were determined. Body fat percentage was assessed by bioelectrical impedance analysis and BP was assessed using an automated device. All variables (except body fat percentage) were transformed to z-scores using published standards.

OUTCOME MEASURES

Linear and Poisson regression was used to explore associations between the adiposity indicators with BP z-score and hypertension. Receiver operating curve (ROC) analysis was used to explore the strength of the adiposity indicators in estimating hypertension risk and sex-stratified optimal adiposity cut-off values associated with hypertension risk.

RESULTS

Significant associations were detected in adjusted and unadjusted models between the adiposity indicators with BP z-score and hypertension (p<0.01 for all). The area under the curve (AUC) values for the adiposity indicators for boys and girls ranged from 0.74 to 0.80, suggesting that the adiposity indicators are fair measures of estimating hypertension risk. Sex-stratified cut-off associated with adverse risk of hypertension for girls and boys, respectively, were at the 92nd and 82nd percentile for BMI z-scores, 65th and 80th percentile for WC z-score, 63rd and 67th percentile for WHtR z-score and at 29.8% and 23.5% for body fat.

CONCLUSION

Our results show associations between adiposity indicators with BP and hypertension and suggests that South Asian children might be at adverse risk of hypertension at levels of adiposity considered normal.

Cross-sectional associations between Ideal Cardiovascular Health scores and vascular phenotypes in 11- to 12-year-olds and their parents: The Longitudinal Study of Australian Children

BACKGROUND

Understanding early-life relationships between the Ideal Cardiovascular Health (ICVH) score and vascular phenotypes could inform likely effectiveness and timing of cardiovascular disease prevention strategies. We aimed to describe associations between ICVH scores and vascular phenotypes in 11- to 12-year-old children and their parents.

METHODS AND RESULTS

Cross-sectional ICVH scores (range 0-7, higher indicating better health), derived by summing dichotomized metrics for cholesterol, glucose, blood pressure (BP), body mass index (BMI), diet, physical activity and smoking, were constructed for 1235 adults (89% female, mean age 43 years) and 1028 children (48% female, 12 years). The median scores were 4 and 5 for adults and children respectively. Child ICVH scores were associated with parent scores (0.18 higher child score per additional point in parent's score, 95% CI 0.12 to 0.22, P < 0.001). Each additional point in the adult ICVH score was associated with slower carotid-femoral pulse wave velocity (PWV, -0.32 m/s, 95% CI -0.37 to -0.27), greater carotid elasticity (0.017%/mm Hg, 95% CI 0.014 to 0.020) and reduced carotid intima-media thickness (IMT, -7.3 μm, 95% CI -12.0 to -2.5). An additional point in the child score was associated with functional phenotypes (PWV -0.07 m/s, 95% CI -0.11 to -0.03; carotid elasticity 0.009%/mm Hg, 95% CI 0.004 to 0.015) but not structural phenotypes (IMT -1.8 μm, 95% CI -5.2 to 1.5).

CONCLUSION

Few Australian children and even fewer parents have ideal cardiovascular health. Lower ICVH scores were associated with adverse adult vascular phenotypes and adverse child vascular function. Family-based interventions optimizing ICVH metrics may delay onset and progression of subclinical atherosclerosis and later cardiovascular disease.

Clinical Practice Guideline for Screening and Management of High Blood Pressure in Children and Adolescents

These pediatric hypertension guidelines are an update to the 2004 "Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents." Significant changes in these guidelines include (1) the replacement of the term "prehypertension" with the term "elevated blood pressure," (2) new normative pediatric blood pressure (BP) tables based on normal-weight children, (3) a simplified screening table for identifying BPs needing further evaluation, (4) a simplified BP classification in adolescents ≥13 years of age that aligns with the forthcoming American Heart Association and American College of Cardiology adult BP guidelines, (5) a more limited recommendation to perform screening BP measurements only at preventive care visits, (6) streamlined recommendations on the initial evaluation and management of abnormal BPs, (7) an expanded role for ambulatory BP monitoring in the diagnosis and management of pediatric hypertension, and (8) revised recommendations on when to perform echocardiography in the evaluation of newly diagnosed hypertensive pediatric patients (generally only before medication initiation), along with a revised definition of left ventricular hypertrophy. These guidelines include 30 Key Action Statements and 27 additional recommendations derived from a comprehensive review of almost 15 000 published articles between January 2004 and July 2016. Each Key Action Statement includes level of evidence, benefit-harm relationship, and strength of recommendation. This clinical practice guideline, endorsed by the American Heart Association, is intended to foster a patient- and family-centered approach to care, reduce unnecessary and costly medical interventions, improve patient diagnoses and outcomes, support implementation, and provide direction for future research.

Sex-specific trajectories of systolic and diastolic blood pressure in youth

BACKGROUND AND OBJECTIVE

High blood pressure early in life is associated with cardiovascular disease morbidity and mortality in adulthood. The objective was to identify sex-specific trajectories of SBP and DBP from early adolescence to early adulthood and to assess the impact of modifiable factors on the trajectories, including BMI, smoking, alcohol use, physical activity, and screen-time.

METHODS

Data were drawn from four waves of a prospective investigation of 1294 youth aged 12-13 years at inception and followed until age 24 years. Group-based trajectory models were used to identify trajectories and assess the impact of modifiable factors in 403 men and 432 women.

RESULTS

Three SBP trajectories were identified in men [corresponding to low (43.2%), medium (45.2%), and high SBP (11.7%)] and women [corresponding to low (48.1%), medium (44.7%), and high SBP (7.2%)]. Similar results were observed for DBP in both sexes. BMI and smoking were associated with higher SBP and DBP values in most trajectory groups, whereas screen-time in both sexes and physical activity in women were associated with high SBP trajectories only.

CONCLUSION

There is heterogeneity in the sex-specific natural course of SBP and DBP in youth and in the magnitude of the effect of modifiable factors on SBP and DBP across trajectories. Distinguishing trajectories allows identification of subgroups at risk of hypertension and cardiovascular disease later in life and in addition can inform the design of targeted interventions to attenuate high SBP and DBP trajectories over time and maintain normal trajectories.