"White coat hypertension" in adolescents: increased values of urinary cortisol and endothelin

Blood pressure standards for pre-school children in Saudi Arabia

The prevalence of hypertension (HTN) in children is increasing. Early detection of HTN in childhood may prevent the occurrence of complications in adult age. Blood pressure (BP) varies between populations according to ethnic and environmental factors. Based on these variations, reference norms developed for one particular population may not be applicable to others. Thus, this study aimed to provide age-, gender-, and height-related BP reference standards using oscillometric techniques for pre-school children in Saudi Arabia. A sub-sample of preschool children aged from 2 to 6 years was selected by multi-stage probability sampling of Saudi population. The samples represented Saudi children from the whole country. Data were collected through a house-to-house survey of all selected households in all 13 regions in the country. Oscillometric devices were used to measure the BP. Data were analyzed to study the distribution pattern of systolic (SBP) and diastolic BP (DBP) and to develop reference values based on age, gender, and height. The values for each age and height percentile were compared with the recent (2017) values of the North American children. A total of 2553 Saudi Arabian children (1299 boys and 1254 girls) aged 2-6 years with complete data on age, gender, height, SBP, and DBP were considered for analysis. Values for SBP and DBP were significantly higher in Saudi children than in the North American children. This study adds evidence to the BP variations between populations with influences such as genetic and environmental factors. The need of every population to define its normal BP standards is essential to avoid unnecessary investigations and anxiety in patients and their parents.

The hypothalamus and its role in hypertension

For the majority of hypertensive patients, the etiology of their disease is unknown. The hypothalamus is a central structure of the brain which provides an adaptive, integrative, autonomic, and neuroendocrine response to any fluctuations in physiological conditions of the external or internal environment. Hypothalamic insufficiency leads to severe metabolic and functional disorders, including persistent increase in blood pressure. Here, we discuss alterations in the neurochemical organization of the paraventricular and suprachiasmatic nucleus in the hypothalamus of patients who suffered from essential hypertension and died suddenly due to acute coronary failure. The changes observed are hypothesized to contribute to the pathogenesis of disease.

Establishment of blood pressure nomograms representative for Egyptian children and adolescents: a cross-sectional study

OBJECTIVE

To define nomograms for blood pressure in Egyptian children and adolescents.

METHODS AND STUDY DESIGN

A total of 60 025 Egyptian children from birth to 19 years were enrolled in this cross-sectional randomised study from December 2015 to March 2017. They were selected from diverse geographical districts in Egypt. Healthy children who fulfilled the inclusion criteria, which included good nutritional history, absence of fever or documented underlying disease at the time of examination, no evidence of haemodynamically significant illness, and no antihypertensive drugs or other chronic drug administration, were included in the study. Body weight, recumbent length (for less than 24 months) and height (from 2 years to 19 years), and blood pressure were measured using standard mercury sphygmomanometers.

RESULTS

Blood pressure increases with age in both boys and girls. The 90th percentile of systolic and diastolic blood pressure among Egyptian children was different from other ethnic populations (American and Turkish children) in both sexes. Systolic and diastolic blood pressure showed a positive correlation with weight and height in both sexes (p<0.001).

CONCLUSION

We assumed that normal blood pressure curves should be used cautiously during childhood, and it is recommended that every population have its own normal standard curve to define measured blood pressure levels in children. These centiles increased our knowledge and awareness of normal blood pressure among Egyptian children and adolescents. The percentiles will distinguish children and young adolescents with increased blood pressure and will be of value to both medical practice and scientific research.

Blood pressure standards for Saudi children and adolescents

BACKGROUND AND OBJECTIVES

Blood pressure levels may vary in children because of genetic, ethnic and socioeconomic factors. To date, there have been no large national studies in Saudi Arabia on blood pressure in children.Therefore, we sought to establish representative blood pressure reference centiles for Saudi Arabian children and adolescents.

SUBJECTS AND METHODS

We selected a sample of children and adolescents aged from birth to 18 years by multi-stage probability sampling of the Saudi population. The selected sample represented Saudi children from the whole country. Data were collected through a house-to-house survey of all selected households in all 13 regions in the country. Data were analyzed to study the distribution pattern of systolic (SBP) and diastolic blood pressure (DBP) and to develop reference values. The 90th percentile of SBP and DBP values for each age were compared with values from a Turkish and an American study.

RESULTS

A total of 16 226 Saudi children and adolescents from birth to 18 years were studied. Blood pressure rose steadily with age in both boys and girls. The average annual increase in SBP was 1.66 mm Hg for boys and 1.44 mm Hg for girls. The average annual increase in DBP was 0.83 mm Hg for boys and 0.77 mm Hg for girls. DBP rose sharply in boys at the age of 18 years. Values for the 90th percentile of both SBP and DBP varied in Saudi children from their Turkish and American counterparts for all age groups.

CONCLUSION

Blood pressure values in this study differed from those from other studies in developing countries and in the United States, indicating that comparison across studies is difficult and from that every population should use their own normal standards to define measured blood pressure levels in children.

Mechanical and circulating biomarkers in isolated clinic hypertension

1. This review examines the current evidence for altered mechanical and circulating biomarkers in isolated clinic hypertension and their potential significance. 2. Arterial stiffness, as assessed by central pulse wave velocity, is influenced by multiple cardiovascular risk factors; however, an independent association with isolated clinic hypertension (ICHT) has not been convincingly shown in four small studies. 3. Endothelial dysfunction, as assessed by brachial artery flow-mediated vasodilation, circulating levels of endothelial markers (e.g. nitrite/nitrate, von Willebrand factor, endothelin-1) and/or circulating levels of inhibitors of vascular nitric oxide (plasma asymmetric dimethylarginine, homocysteine), has been shown to be present in established hypertension and to a variable and inconsistent extent in subjects with ICHT. 4. Evidence of increased oxidative stress in ICHT versus normotensive subjects was found in two of three studies. 5. Circulating inflammatory markers C-reactive protein and plasminogen activator inhibitor-1 were significantly increased in two of three and two of two studies, respectively, in ICHT compared with normotensive subjects. 6. Urinary albumin excretion is a marker of both arterial and renal disease. The consensus from seven studies in patients with ICHT is that albuminuria is not an independent marker for ICHT. 7. Studies to date assessing biomarkers in ICHT have been small and cross-sectional. Larger, long-term longitudinal studies of arterial functional and circulating biomarkers are required to assess the potential vascular impact of ICHT.

Psychosocial and physiological stress among women leaving welfare

Women receiving Temporary Assistance for Needy Families (TANF) report more stress and have poorer health than women in the general population. Studies suggest chronic stress may contribute to poor health via physiological mechanisms, yet little is known about these mechanisms in this population. This study examined psychosocial stress, salivary cortisol, 24-hr ambulatory blood pressure and heart rate, and health among 40 single mothers before and after exiting TANF. As a group, perceived stress decreased after leaving TANF (p = .02), with other measures of psychosocial and physiological stress remaining unchanged. Within participants, changes in psychosocial stress predicted depression and general health over time (adjusted R(2) = .30 and .22; p = .006 and .004, respectively). These findings indicate psychosocial stress is positively associated with depression and negatively associated with general health as women exit welfare. Psychosocial stress was not associated with changes in physiologic indicators of stress.

White coat hypertension in childhood: evidence for end-organ effect

OBJECTIVE

To evaluate the hypothesis that white coat hypertension (WCH) represents a prehypertensive state by correlating ambulatory blood pressure monitoring (ABPM) results with BP response to treadmill exercise (TE) and echocardiographic measurement of left ventricular mass index (LVMI) in children with high blood pressure (HBP).

STUDY DESIGN

We evaluated 119 consecutive children age 6 to 18 years (mean = 13.3 years; 65% male) referred for HBP. Office systolic BP (SBP) exceeded the 95th percentile for age/sex/height in all of the children; 10% also had elevated diastolic BP (DBP). WCH was defined as elevated office SBP +/- elevated DBP with normal mean awake ABPM-SBP. ABPM classified 62 subjects as having WCH and 57 as having HBP.

RESULTS

Office BP did not differ between the 2 groups. As defined, awake ABPM-SBP was lower in the WCH group (males: HBP, 142 +/- 12 vs WCH, 124 +/- 5; females: HBP, 137 +/- 8 vs WCH, 121 +/- 5). Awake and asleep DBP and asleep SBP were significantly lower in the WCH group. On TE, maximal SBP exceeded norms for age/sex/body surface area in 63% of the HBP group and 38% of the WCH group. LVMI exceeded the 95th percentile for age/sex in 59% of the males and 90% of the females in the HBP group and in 33% of the males and 36% of the females in the WCH group.

CONCLUSIONS

Exaggerated exercise BP and/or increased LVMI in 62% of those subjects with WCH suggest that this diagnosis in children may represent a prehypertensive state.

Increased circulating concentrations of asymmetric dimethylarginine (ADMA) in white coat hypertension

Elevated plasma levels of the endogenous nitric oxide (NO) synthase inhibitor asymmetric dimethylarginine (ADMA) contribute to endothelial dysfunction and seem to be a predictor for cardiovascular mortality. Elevated ADMA plasma concentrations have been demonstrated in patients with hypertension. However, the plasma concentrations of ADMA in white coat hypertension (WCH) has not been previously studied. The aim of this study was to evaluate ADMA in WCH and compare with normotensive (NT) and hypertensive (HT) patients. We also evaluated the relation between ADMA and NO in these three groups. For this purpose, 34 NT, 34 white coat hypertensive (clinical hypertension and ambulatory daytime blood pressure <135/85 mmHg) and 34 HT patients were recruited in this study. The subjects were matched for age, gender, body mass index (BMI) and the patients with smoking habit, dyslipidaemia and diabetes mellitus were excluded. The ADMA levels were determined by high performance liquid chromatography. Plasma ADMA levels were significantly higher in WCH group than in the NT group (3.21+/-0.49 micromol/l vs 2.84+/-0.58 micromol/l, P=0.046). It was significantly higher in the HT group than in the NTs (4.24+/-0.38 micromol/l, P<0.001). There was also a significant difference between the HT and WCH groups (P<0.001). The WCH subjects had significantly higher levels of NO than the HTs (41.68+/-2.23 vs 32.18+/-2.68 micromol/l; P<0.001) and significantly lower values than the NTs (48.24+/-4.29 micromol/l; P<0.001). In WCH and HT group, there was a negative correlation between ADMA and NO (r=-0.515, P=0.003 and r=-0.389, P=0.034, respectively). In NT subjects, there was no correlation between these two parameters (r=-0.287, P=0.124). The correlation between ADMA and NO was stronger in WCH group than in HT group. Although NO levels in HT patients were lower than WCHs and ADMA levels were higher in HT patients than WCHs, the negative correlation of these two parameters were more pronounced in WCH group. Decreased NO and increased ADMA levels in WCH may indicate endothelial dysfunction. Our data indicate also that WCH represent an intermediate group between NT and HT when endothelial dysfunction is concerned.

Endothelium and angiogenesis in white coat hypertension

Hypertensive patients are at particular risk of cardiovascular complications, possibly related to endothelial damage or dysfunction, or to abnormal angiogenesis. The aim of this study was to compare the risk conferred by white coat hypertension (WCH) vs sustained hypertension in the development of the endothelial dysfunction and abnormal angiogenesis by evaluating nitric oxide (NO=NO2+NO3), endothelin-1 (ET-1), vascular endothelial growth factor (VEGF), and E-selectin levels in plasma. The study group included 102 subjects, 34 with WCH (17 male and 17 female patients) aged 49+/-11 years, 34 sustained hypertensives (HT) (15 male and 19 female patients) aged 47+/-11 years and 34 normotensive control subjects (NT) (16 male and 18 female patients) aged 48+/-10 years. WCH was defined as clinical hypertension and daytime ambulatory blood pressure less than 135/85 mmHg. The subjects were matched for age, gender, body mass index and the patients with smoking habit, dyslipidaemia, and diabetes mellitus were excluded from the study. The NO, ET-1, VEGF and E-selectin levels were analysed by ELISA technique. The WCH subjects had significantly higher levels of NO than the HT (41.68+/-2.23 vs 32.18+/-2.68 micromol/l; P<0.001) and significantly lower values than the NT (48.24+/-4.29 micromol/l; P<0.001). ET-1 levels of the WCH group were significantly higher than the NT (8.10+/-0.92 vs 5.95+/-0.26 ng/ml; P<0.001) and significantly lower than the HT (11.46+/-0.59 ng/ml; P<0.001). Considering with VEGF, the WCH group had significantly higher levels than the NT (195.88+/-11.84 vs 146.26+/-18.67 pg/ml; P<0.001), but the difference from the HT group was not significant (203.35+/-7.48 pg/ml; P=0.062). E-selectin in the WCH group was significantly lower than the HT (4.77+/-0.52 vs 8.49+/-2.85; P<0.001), but the difference from the NT group was not significant (3.86+/-0.67; P=0.077). Our data demonstrate that WCH is associated with endothelial dysfunction and abnormal angiogenesis. The degree of these changes is not as severe as observed in hypertensive population.

Pediatric hypertension: recent literature

This article reviews selected recent literature specifically concerning pediatric hypertension, much of which has focused on measurement and monitoring of blood pressure, as well as on evaluating antihypertensive medications. Normative data for blood pressure in children have been widely available for some time, based upon seated in-office measurements. In recent years, ambulatory blood pressure monitoring (ABPM), facilitated by user-friendly instrumentation, has become more commonplace, though norms are not based on large populations. However, ABPM has important uses in assessing blood pressure as well as in monitoring antihypertensive. This review discusses issues involved in determining blood pressure, as well as the utility of ABPM in several situations. Recent developments concerning pediatric antihypertensive therapy are considered, as well as new information relevant to the diagnosis, course and treatment of hypertension in children and adolescents.

Paraventricular nucleus of the human hypothalamus in primary hypertension: activation of corticotropin-releasing hormone neurons

By using quantitative immunohistochemical and in situ hybridization techniques, we studied corticotropin-releasing hormone (CRH) -producing neurons of the hypothalamic paraventricular nucleus (PVN) in patients who suffered from primary hypertension and died due to acute cardiac failure. The control group consisted of individuals who had normal blood pressure and died of acute heart failure due to mechanical trauma. Both magno- and parvocellular populations of CRH neurons appeared to be more numerous in the PVN of hypertensive patients. Quantitative analysis showed approximately a twofold increase in the total number of CRH neurons and a more than fivefold increase in the amount of CRH mRNA in the hypertensive PVN compared with the control. It is suggested that synthesis of CRH in hypertensive PVN is enhanced. Increased activity of CRH-producing neurons in the PVN of hypertensive patients is proposed not only to entail hyperactivity of the hypothalamo-pituitary-adrenal axis, but also of the sympathetic nervous system and, thus, to be involved in the pathogenesis of hypertension.

Less difference between office and ambulatory blood pressure in women than in men both before and during antihypertensive treatment

In 199 subjects (56% women) with a diastolic blood pressure (BP) of 95-115 mmHg, 5 mg of either amlodipine or felodipine extended release (ER) was given for 4 weeks following 4 weeks of placebo-treatment. BP was measured by conventional clinic BP technique and by 24-h ambulatory BP monitoring (Spacelab 90202/90207). Men and women had identical clinic BP at baseline and it was lowered equally much by 4 weeks of treatment (men: 158/101 and 147/93, women: 159/102 and 149/93 mmHg, respectively). However, ambulatory BP was higher in women than in men both before and after treatment (men: 145/91 and 134/85, women: 149/95 and 140/89 mmHg, respectively, p < 0.05 for both comparisons). The difference between clinic BP and daytime ambulatory BP was higher in men than in women (systolic men: 8.1 +/- 14, women: 3.7 +/- 15 mmHg, respectively, p = 0.04; diastolic men: 5.5 +/- 8.0, women: 2.1 +/- 8.3 mmHg, p = 0.004). The correlation between the treatment effect measured by ambulatory and clinic BP was poor (systolic r = 0.26, p < 0.0001; diastolic r = 0.17, p = 0.03) and was unaffected by exclusion of subjects with normal ambulatory BP. The poor correlation between treatment effects measured as clinic and ambulatory BP is intriguing, and suggests that using ambulatory BP instead of clinic BP for monitoring the treatment of hypertension could affect the clinical outcome.