Pediatric hypertension: recent literature

Diagnosis of hypertension: Ambulatory pediatric American Heart Association/European Society of Hypertension versus blood pressure load thresholds

The agreement between the traditionally-used ambulatory blood pressure (ABP)-load thresholds in children and recently-recommended pediatric American Heart Association (AHA)/European Society of Hypertension (ESH) ABP thresholds for diagnosing ambulatory hypertension (AH), white coat hypertension (WCH), and masked hypertension (MH) has not been evaluated. In this cross-sectional study on 450 outpatient participants, the authors evaluated the agreement between previously used ABP-load 25%, 30%, 40%, 50% thresholds and the AHA/ESH thresholds for diagnosing AH, WCH, and MH. The American Academy of Pediatrics thresholds were used to diagnose office hypertension. The AHA threshold diagnosed ambulatory normotension/hypertension closest to ABP load 50% in 88% (95% CI 0.79, 0.96) participants (k 0.67, 95% CI 0.59, 0.75) and the ESH threshold diagnosed ambulatory normotension/hypertension closest to ABP load 40% in 86% (95% CI 0.77, 0.94) participants (k 0.66, 95% CI 0.59, 0.74). In contrast, the AHA/ESH thresholds had a relatively weaker agreement with ABP load 25%/30%. Therefore, the diagnosis of AH was closest between the AHA threshold and ABP load 50% (difference 3%, 95% CI -2.6%, 8.6%, p = .29) and between the ESH threshold and ABP load 40% (difference 4%, 95% CI -2.1%, 10.1%, p = .19) than between the AHA/ESH and ABP load 25%/30% thresholds. A similar agreement pattern persisted between the AHA/ESH and various ABP load thresholds for diagnosing WCH and MH. The AHA and ESH thresholds diagnosed AH, WCH, and MH closest to ABP load 40%/50% than ABP load 25%/30%. Future outcome-based studies are needed to guide the optimal use of these ABP thresholds in clinical practice.

Sleep duration and its association with ambulatory blood pressure in a school-based, diverse sample of adolescents

BACKGROUND

Evidence is accumulating that sleep duration is related to blood pressure (BP) and hypertensive status, but the strength of the association varies by age, and findings are inconsistent for adolescents. This cross-sectional study tested the hypothesis that sleep duration, both during the night and during naps, would be negatively associated with ambulatory systolic BP (SBP) and diastolic BP (DBP) measured over 24 hours in adolescents.

METHODS

In this ethnically diverse (37% non-Hispanic black, 31% Hispanic, 29% non-Hispanic white, 3% other), school-based sample of 366 adolescents aged 11-16 years, ambulatory BP was measured every 30 minutes for 24 hours on a school day; actigraphy was used to measure sleep duration. Covariables included demographic factors, anthropometric indices, physical activity, and position and location at the time of each BP measurement. Mixed models were used to test day and night sleep duration as predictors of 24-hour SBP and DBP, controlling for covariables.

RESULTS

The mean sleep duration was 6.83 (SD = 1.36) hours at night, and 7.23 (SD = 1.67) hours over 24 hours. Controlling for duration of sleep during the day and covariables, each additional hour of nighttime sleep was associated with lower SBP (-0.57; P < 0.0001); controlling for nighttime sleep duration and covariables, each additional hour of daytime sleep was associated with lower SBP (-0.73; P < 0.001) and lower DBP (-0.50; P < 0.001).

CONCLUSIONS

Longer sleep duration was significantly associated with lower ambulatory SBP and DBP in adolescents. The findings have potential implications for cardiovascular health in this age group.

Blood pressure load, proteinuria and renal function in pre-hypertensive children

It is as yet unclear whether blood pressure load (BPL) can affect renal function in pre-hypertensive children. We have studied 250 children, with a mean age of 9.12 +/- 3.28 years, with the aim of assessing if pre-hypertension in children can indeed affect renal function. The study cohort consisted of 146 children with pre-hypertension (group P) and a control group of 104 children with normal blood pressure (group C). All children were tested for orthostatic proteinuria, an exclusion criterion, glomerular filtration rate (GFR), and proteinuria, and ambulatory blood pressure monitoring was performed. Based on the BPL, group P was further subdivided into group P1 (BPL <or= 40%, low BPL) and group P2 (BPL > 40%, high BPL). We found that GFR was reduced in pre-hypertensive children (90.74 +/- 48.69 vs. 110.32 +/- 20.30 ml/min per 1.73 m(2), p < 0.0001) and that proteinuria was increased (145.36 +/- 110.91 vs. 66.84 +/- 42.94 mg/m(2) per 24 h; p < 0.0001). However, mean values were still within normal limits. A comparison of the group with high BPL and that with low BPL revealed that the former had relatively reduced GFR (79.15 +/- 42.04 vs. 96.78 +/- 51.20 ml/min per 1.73 m(2); p < 0.006) and increased proteinuria (198.29 +/- 142.17 vs. 118.31 +/- 80.07 mg/m(2) per 24 h; p < 0.036). In comparison to the reference values of the normal population, the GFR was reduced and proteinuria was increased in the group with high BPL. Based on our results, pre-hypertension in children with high BPL seems to be associated with reduced GFR and increased proteinuria. A reasonable doubt remains that the patients with higher proteinuria and larger reduction of GFR may harbor an as yet unknown subclinical renal condition responsible for the onset of pre-hypertension. Therefore, children with even mildly elevated BP are at risk of developing renal damage and should change their lifestyle to prevent further increases in BP.

Ambulatory blood pressure and increased left ventricular mass in children at risk for hypertension

OBJECTIVE

To relate ambulatory blood pressure (ABP) to cardiac target organ measurement in children at risk for primary hypertension (HTN).

STUDY DESIGN

Left ventricular mass index (LVMI) and ABP were measured concomitantly in children (6 to 18 years) at risk for hypertension using a cross-sectional study design.

RESULTS

LVMI showed a significant positive correlation with 24-hour systolic blood pressure (SBP) load, SBP index (SBPI), and standard deviation score (SDS). When subjects were stratified by LVMI percentile, there were significant differences in SBP load, 24-hour SBPI, and 24-hour SSDS. The odds ratio (OR) of having elevated LVMI increased by 54% for each incremental increase of SDS in 24-hour SSDS after controlling for race and BMI (OR = 1.54, unit = 1 SDS, CI = 1.1, 2.15, P = .011) and increased by 88% for each increase of 0.1 in BPI (OR = 1.88, CI = 1.03, 3.45, P = .04). Subjects with stage 3 HTN had significantly greater mean LVMI compared with normal subjects (P = .002 by ANOVA; LMVI, 31.6 +/- 7.9 versus 39.5 +/- 10.4).

CONCLUSIONS

As systolic ABP variables increase, there is greater likelihood for increased LVMI. Staging based on ABPM allows assessment of cardiovascular risk in children with primary hypertension.

Comparison of ambulatory blood pressure and Task Force criteria to identify pediatric hypertension

The aim of this study was to assess the level of agreement between central European ambulatory blood pressure monitoring (ABPM) and American Task Force (TF) criteria when applied to blood pressure (BP) measurements collected by ABPM to evaluate patients with hypertension. In 169 patients, we applied both sets of criteria and calculated mean daytime and nighttime BP and daytime BP loads. The frequency of hypertension for daytime systolic BP was significantly higher when TF criteria were used (p <or= 0.001). However, the frequency of hypertension for nighttime systolic BP was significantly increased when ABPM criteria were applied (p <or= 0.01). Therefore, with daytime ABPM measurements, hypertension was overdiagnosed with TF criteria, while nighttime hypertension was underdiagnosed using TF criteria. In contrast with previous reports, 40% of our patients with essential hypertension showed absence of nighttime dipping, regardless of the criteria used. The number of hypertensive patients was significantly higher using ABPM compared to TF criteria when patients with BP load >or=50% were evaluated (p <or= 0.01). Therefore, current recommendations for ABPM use in children such as to define white coat hypertension or as a screening tool to differentiate between primary and secondary hypertension need to be validated using yet to be produced normative ABPM criteria in American children.

Screening for hypertension in high school

Arterial hypertension is a major risk factor for atherosclerotic ischemic heart disease and cerebrovascular stroke. Blood pressure measurements were taken in the supine position in 6,282 healthy adolescents (3073 boys, 3209 girls) aged 13-17 years of both sexes. Forty-eight subjects were found to have hypertension: 35 idopathic and 13 secondary to reflux nephropathy, chronic glomerulonephritis, coarctation of the aorta, and hemolytic uremic syndrome. Systolic blood pressure was significantly higher among males than females at ages 15-17 years (p<0.001); diastolic blood pressure was higher among males at age 17 years only (p<0.05). Males with BMI>17 exhibited higher systolic blood pressure than females. Prevalence of hypertension, mostly primary, in a large cohort of students was 0.76%. Early screening is important for early interventions and reducing cardiovascular morbidity and mortality in adulthood.

Ambulatory blood pressure monitoring: mean blood pressure and blood pressure load

Ambulatory blood pressure monitoring (ABPM) is commonly used to diagnose pediatric hypertension. Using ABPM, hypertension is usually defined as a mean BP greater than the 95th percentile for height. A BP load >30% (% of BP readings greater than the 95th percentile) is also used for the diagnosis of hypertension. The objective of this study was to determine the agreement between mean BP greater than the 95th percentile and 30% BP load for the diagnosis of hypertension using ABPM. All ABPM records (n =1,009) of patients referred for hypertension to a pediatric center were retrieved. Scans were excluded if: age was >19 and height <115 cm or >185 cm. Mean BP and BP loads were calculated for 728 scans. Agreement between mean BP greater than the 95th percentile for height and various BP loads were calculated using the kappa coefficient. The kappa coefficient of agreement between mean BP greater than the 95th percentile and 30% BP load was 0.56 and 0.57 for daytime systolic and diastolic BP, respectively. The agreement between mean night-time BP greater than the 95th percentile and 30% BP load was 0.70 and 0.66 for systolic and diastolic BP, respectively. Agreement between mean BP greater than the 95th percentile and 30% BP load is only moderate to good. Maximum agreement between mean BP greater than the 95th percentile and BP load is achieved at 50% BP load.

Intrauterine exposure to diabetes is a determinant of hemoglobin A(1)c and systolic blood pressure in pima Indian children

CONTEXT/OBJECTIVE

Given the increasing rates of both childhood obesity and type 2 diabetes (T2DM), we investigated whether maternal diabetes status during pregnancy is a determinant of risk factors associated with T2DM or cardiovascular disease in offspring during childhood.

DESIGN/PARTICIPANTS

Forty-two Pima Indians, aged 7-11 yr, were identified retrospectively from maternal oral glucose tolerance tests as offspring of a diabetic pregnancy (22 ODM, eight males, 14 females) or offspring born before the mother developed diabetes (20 PRE, 12 males, eight females). SETTING/MAIN OUTCOME MEASURES: Weight, height, body mass index, percent body fat, blood pressure, and fasting concentrations of glucose, insulin, hemoglobin A1c (HbA1c), total cholesterol, triglycerides, and high-density lipoprotein-cholesterol were measured while staying in an in-patient clinical research unit and compared in cross-sectional analyses.

RESULTS

After adjustment for age and gender, ODM had significantly higher concentrations of HbA1c (ODM = 5.7 +/- 0.4, PRE = 5.0 +/- 0.4%, P = 0.002), higher systolic (SBP) blood pressure (ODM = 118 +/- 13, PRE = 107 +/- 10 mm Hg; P = 0.02), and lower concentrations of high-density lipoprotein (ODM = 41 +/- 9, PRE = 48 +/- 6 mg/dl, P = 0.03) than PRE. Maternal diabetes status during pregnancy persisted as a significant determinant of SBP (beta = 7.50, P = 0.03) and HbA1c (beta = 0.43, P = 0.002), independent of age, gender, and percent body fat.

CONCLUSION

Intrauterine exposure to diabetes is a significant determinant of higher SBP and HbA1c during childhood, independent of adiposity and a genetic predisposition to T2DM. These data suggest that in utero exposure to diabetes confers an additional independent risk for the development of T2DM and/or cardiovascular disease later in life.

Comparison of the automated non-invasive oscillometric blood pressure monitor (BpTRU) with the auscultatory mercury sphygmomanometer in a paediatric population

BACKGROUND

To directly compare the accuracy of the BpTRU (an automated oscillometric blood pressure device) with standard auscultatory mercury sphygmomanometry in a pediatric population.

DESIGN

The BpTRU was connected in parallel with a standard mercury sphygmomanometer. Two observers measured the blood pressures at the same time as it was being measured by the BpTRU. The observers and the BpTRU were all blinded from each other.

METHODS

For each of the demographic data--subject age, sex and arm sizes--the mean, standard deviation (SD) and range was calculated. The difference between the mean BpTRU and the standard reference measurements (observer average) was calculated with SD and ranges. The percentage of measurements within 5, 10 and 15 mmHg agreement was expressed.

RESULTS

From the 36 subjects recruited aged 3-18 years, 162 pairs of sitting blood pressures were included. The difference between the mean BpTRU readings and the reference standard measurements (as determined by the observers) was 1.45+/-5.67 mmHg for systolic blood pressures, and -3.24+/-7.39 mmHg for diastolic pressure and 0.20+/-2.47 bpm for heart rate.

CONCLUSION

The BpTRU is of similar accuracy in measuring blood pressure in children as it was in an adult population.

Elevated blood pressure and decreased cognitive function among school-age children and adolescents in the United States

OBJECTIVE

To evaluate the relationship between elevated blood pressure (BP) and cognitive test performance in a nationally representative sample of children. Study design The National Health and Nutrition Examination Survey III provides cross-sectional data for children 6 to 16 years, including BP and cognitive test scores. Elevated BP was defined as systolic or diastolic BP >or=90th percentile. Cognitive tests were compared for children with elevated and normal BP. Linear regression was used to evaluate the relation between elevated BP and decreased test scores.

RESULTS

Among the 5077 children, 3.4% had systolic BP >or=90th percentile and 1.6% diastolic BP >or=90th percentile. Children with elevated systolic BP had lower average scores compared with normotensive children for digit span (7.9 vs 8.7, P=.01), block design (8.6 vs 9.5, P=.03), and mathematics (89.6 vs 93.8, P=.01). Elevated diastolic BP was associated with lower average scores on block design (9.5 vs 11, P=.01). Linear regression showed that elevated systolic BP was independently associated with lower digit span scores (P=.032).

CONCLUSION

Children with elevation of systolic BP are at risk for central nervous system end-organ damage, as manifested by decreased digit span test scores.

Hypertension in adolescents: a review of diagnosis and management

Long-term hypertension contributes to significant cardiovascular and renal morbidity and mortality. Although chronic hypertension is much rarer in the adolescent population than in adults, identifying the hypertensive adolescent and intervening with risk factors such as obesity that may promote hypertension is important for the clinician treating adolescents. Since both primary and secondary causes of hypertension may exist in the adolescent, a thorough and sequential clinical and diagnostic evaluation must be undertaken, including screening urinalysis, blood chemistries, and renal sonography. There are pitfalls in interpreting casual blood pressure measurements in adolescents, and the role of ambulatory blood pressure monitoring is evolving. Lifestyle modifications, including diet, exercise, and limitation of sodium intake, remain the foundation of treatment. Commonly used medications include calcium channel blockers, angiotensin receptor blockers and converting enzyme inhibitors, beta blockers, and diuretics. When considering medication in the hypertensive adolescent, potential complications of therapy must be reviewed in light of the physical and psychosocial changes ongoing in this age group.