Ambulatory blood pressure status in children: comparing alternate limit sources.

The American Heart Association has included alternate ambulatory blood pressure (ABP) limits for children published by Wühl in 2002. These updated limits employ the same pediatric cohort data as the previous ABP limits published by Soergel in 1997 but differ in analysis technique. The implications of changing ABP limit source on the diagnosis of hypertension has yet to be examined in a large pediatric cohort. We reviewed 741 ABP monitorings performed in children referred to our hypertension clinic between 1991-2007. Hypertension was defined as 24-h mean blood pressure ≥ 95 th percentile or 24-h blood pressure load ≥ 25%, by Soergel and Wühl limits separately. Six hundred seventy-three (91%) children were classified the same by both limit sources. Wühl limits were more likely than Soergel to classify a child as hypertensive (443 vs. 409, respectively). There was an increased classification of prehypertension and decreased white-coat hypertension by the Wühl method, whereas ambulatory and severe hypertension counts remained relatively the same by both limits sources. The use of either limit source will not significantly affect most clinical outcomes but should remain consistent over long-term research projects. Collection of new normative data from a larger, multiethnic population is needed for better measurement of ABP in children.

Race and Obesity in Adolescent Hypertension.

BACKGROUND AND OBJECTIVES: The overall prevalence of essential hypertension in adolescents may be growing. Differences in blood pressure (BP) are well established in adults, but are less clear in adolescents. We hypothesize that the prevalence of hypertension differs by race/ethnicity among adolescents at school-based screenings. METHODS: We performed school-based BP screening in over 20 000 adolescents from 2000 to 2015. Race/ethnicity was self-reported. Height and weight were measured to determine BMI, and BP status was confirmed on 3 occasions to diagnose sustained hypertension according to Fourth Working Group Report criteria. RESULTS: We successfully screened 21 062 adolescents aged 10 to 19 years (mean, 13.8 years). The final prevalence of sustained hypertension in all subjects was 2.7%. Obesity rates were highest among African American (3.1%) and Hispanic (2.7%) adolescents. The highest rate of hypertension was seen in Hispanic (3.1%), followed by African American (2.7%), white (2.6%), and Asian (1.7%) adolescents (P = .019). However, obese white adolescents had the highest prevalence of sustained hypertension (7.4%) compared with obese African American adolescents (4.5%, P < .001). At lower BMI percentiles (<60th percentile), Hispanic adolescents actually had the lowest predicted prevalence of hypertension among the 4 groups. CONCLUSIONS: The prevalence of hypertension varies among different race/ethnicities. Although obesity remains the strongest predictor of early hypertension, the strength of this relationship is intensified in Hispanic and white adolescents, whereas it is lessened in African American adolescents.

Left Ventricular Hypertrophy Phenotype in Childhood-Onset Essential Hypertension.

The aim of this study was to determine the risk factors associated with left ventricular (LV) hypertrophy (LVH) among 89 untreated children with primary hypertension. Clinic hypertension was confirmed by 24-hour ambulatory blood pressure (BP) monitoring. LV mass (LVM) index was calculated as LVM (g)/height (m)(2.7) and LVH was defined as LVM index >95th percentile. Children with (n=32) and without (n=57) LVH were compared. Both obesity and systolic BP were independently associated with LVH, with a higher contribution by body mass index. Obesity contributed significantly, with a nearly nine-fold increased risk of LVH. There was evidence of effect modification by the presence or absence of obesity on the relationship between systolic BP and LVH, whereby the relationship existed mainly in nonobese rather than obese children. Hence, to achieve reversal of LVH, clinicians should take into account both BP control and weight management.

Myocardial Performance Index in Childhood Onset Essential Hypertension and White Coat Hypertension.

BACKGROUND: As a global measure of ventricular systolic and diastolic function, the myocardial performance index (MPI) can be an early indicator of hypertensive cardiomyopathy in children with essential hypertension (EH). METHODS: Children with untreated newly diagnosed EH and white coat hypertension (WCH) by a 24-hour ambulatory blood pressure monitoring (ABPM), both groups without any identifiable etiology for the hypertension, were enrolled for the study. Echocardiograms and vascular ultrasounds for carotid artery intimal medial thickness were performed on all children prior to therapy. Diastolic function (peak E and A velocities, E/A ratio, isovolumic relaxation time, and deceleration times) and MPI were evaluated by simultaneous transmitral and transaortic spectral Doppler flow velocities. Systolic function was evaluated by shortening fraction and ejection fraction. RESULTS: A cohort of 66 children (24 with EH, 42 with WCH, males 61%, median age of 13 years, range 10-17 years) were enrolled in the study. The demographic, anthropometric, laboratory tests, vascular ultrasound, and conventional echocardiographic parameters were similar between the 2 groups. There was a very small difference in MPI between the EH and WCH children (0.28 SD: 0.07 vs. 0.31 SD: 0.08, P = 0.045). However, in EH children, MPI increased by 0.14 units for every 10 unit increase in mean ABPM systolic BP (95% confidence interval: 0.03-0.25). CONCLUSIONS: We found the increasing MPI was associated with increasing 24-hour mean systolic BP in children with EH. Therefore, MPI may have utility as a single, quick, noninvasive method of detection and tracking of subclinical hypertensive heart disease.

Detection of early diastolic alterations by tissue Doppler imaging in untreated childhood-onset essential hypertension.

The aim of the study was to determine the presence of preclinical diastolic dysfunction in hypertensive children relative to normotensive children by Tissue Doppler Imaging (TDI). We prospectively enrolled children with untreated essential hypertension in absence of any other disease and a matched healthy control group with normal blood pressure (BP); both groups confirmed by clinic BP and a 24-hour ambulatory BP monitoring. Echocardiographic diastolic parameters were determined using spectral transmitral inflow Doppler, flow propagation velocity, TDI, and systolic parameters were determined via midwall shortening fraction and ejection fraction. A total of 80 multiethnic children were prospectively enrolled for the study: 46 hypertensive (median age, 13 years; 72% males) and 34 control (median age, 14 years; 65% males). The only echocardiography parameters that had a statistically significant change compared with the control children, were regional mitral Ea, Aa, and the E/Ea ratio by TDI. In comparison with controls, hypertensive children had lower Ea and Aa velocities of anterior and posterior walls and higher lateral wall E/Ea ratio. The decrease in posterior wall Ea and Aa remained significant after adjustment for gender, age, body mass index, ethnicity, and left ventricular hypertrophy on multivariate analysis. The lateral and septal wall E/Ea ratios correlated significantly with fasting serum insulin levels on similar multivariate analysis. Decreased regional TDI velocities were seen with preserved left ventricular systolic function even when other measures of diastolic dysfunction remained unchanged in untreated hypertensive children. Hypertension and serum insulin levels had strong associations with preclinical diastolic alterations in children.

Ambulatory blood pressure patterns in children with chronic kidney disease.

Ambulatory blood pressure (BP) monitoring (ABPM) is the best method of detecting abnormal BP in patients with chronic kidney disease (CKD), whose hypertension may be missed with casual BP measurements. We report ABPM findings in 332 children 1 year after entry in the Chronic Kidney Disease in Children cohort study. All of the subjects underwent casual and ambulatory BP measurement. BP was categorized based on casual and ABPM results into normal (42%), white-coat (4%), masked (35%), and ambulatory (14%) hypertension. Only half of the subjects had a normal ABPM. BP load was elevated (>25%) in 52% (n = 172), whereas mean BP was elevated in 32% (n = 105). In multivariate analysis, those using an angiotensin-converting enzyme inhibitor were 89% more likely to have a normal ABPM than those who did not report using an angiotensin-converting enzyme inhibitor (odds ratio, 1.89 [95% CI, 1.17-3.04]). For every 20% faster decline in annualized glomerular filtration rate change, the odds of an abnormal ABPM increased 26% (odds ratio, 1.26 [95% CI, 0.97-1.64]). A 2.25-fold increase in urine protein:creatinine ratio annualized change was associated with a 39% higher odds of an abnormal ABPM (odds ratio, 1.39 [95% CI, 1.06-1.82]). Abnormalities on ABPM are common in children with chronic kidney disease and are strongly associated with known risk factors for end-stage renal disease. Individuals on angiotensin-converting enzyme inhibitors were less likely to have abnormal ABPM, suggesting a possible therapeutic intervention. ABPM should be used to monitor risk and guide therapy in children with chronic kidney disease.

Isolated systolic hypertension, obesity, and hyperkinetic hemodynamic states in children.

OBJECTIVE: To determine the factors that contribute to the pathogenesis of isolated systolic hypertension in children. METHODS: School-based measurement was performed of blood pressure (BP), heart rate, weight, and height in 2460 students (49% Hispanic, 31% black, 13% white) 12 to 16 years of age in 8 urban public schools. An independent group of 71 untreated children underwent 24-hour ambulatory BP monitoring (ABPM) to confirm clinic hypertension and assess circadian BP patterns. RESULTS: Hypertension and obesity were found in 17% and 23% of students, respectively. Among hypertensive students, 88% (363/413) had isolated systolic hypertension. Hypertension was more prevalent in obese than nonobese students (33% vs 11%, P <.0001). Obese hypertensive students had higher resting heart rate than nonobese normotensive patients (85.9 vs 79.6 beats/min, P <.001). Among patients who underwent ABPM, isolated systolic hypertension was found in 51% (36/71) by clinic BP and in 62% (18/29) with confirmed hypertension by ABPM. Blood pressure variability during daytime and sleep periods was higher in obese than nonobese patients for systolic BP (P <.01) and diastolic BP (P <.05). CONCLUSIONS: The findings of increased heart rate and BP variability in obese children with isolated systolic hypertension suggest that sympathetic nervous system hyperactivity may contribute to its pathogenesis.

Overweight, ethnicity, and the prevalence of hypertension in school-aged children.

OBJECTIVES: To describe the current prevalence of pediatric hypertension and the relationships between gender, ethnicity, overweight, and blood pressure. METHODS: School-based screening was performed in 5102 children (13.5 +/- 1.7 years) from May through November 2002. Age, gender, ethnicity, weight, and height were ascertained, and body mass index (BMI) was calculated as weight (kg)/height (m2). Overweight was defined as BMI > or =95th percentile. Students with blood pressure >95th percentile on the first screening underwent a second screening 1 to 2 weeks later, and then a third screening if blood pressure was >95th percentile at the second screening. RESULTS: Ethnicity distribution was 44% white, 25% Hispanic, 22% African American, and 7% Asian. Overall, overweight prevalence was 20%, which varied significantly by ethnicity (31% Hispanic, 20% African American, 15% white, and 11% Asian). The prevalence of elevated blood pressure after first, second, and third screenings was 19.4%, 9.5%, and 4.5%, respectively. Elevated blood pressure on first screening was highest among Hispanics (25%) and lowest among Asians (14%). Ethnic differences in the prevalence of hypertension (elevated blood pressure on 3 screenings) were not significant after controlling for overweight. The prevalence of hypertension increased progressively as the BMI percentile increased from < or =5th percentile (2%) to > or =95th percentile (11%). After adjustment for gender, ethnicity, overweight, and age, the relative risk of hypertension was significant for gender (relative risk: 1.50; confidence interval: 1.15, 1.95) and overweight (relative risk: 3.26; confidence interval: 2.50, 4.24). CONCLUSIONS: These results confirm an evolving epidemic of cardiovascular risk in youth, as evidenced by an increase in the prevalence of overweight and hypertension, notably among ethnic minority children.