How are hypertensive children evaluated and managed? A survey of North American pediatric nephrologists

Treatment of hypertension in children and adolescents

The treatment of hypertension in children and adolescents has been markedly changed in recent years by several factors, including the publication of new consensus recommendations, the obesity epidemic, and the increased availability of information on efficacy and safety of antihypertensive medications in the young. In this review we present an updated approach to the outpatient management of hypertension in the child or adolescent, utilizing representative cases to illustrate important principles as well as possible controversies.

Concepts guiding therapy for hypertension in children

Increasing attention has been focused on identifying children with prehypertension and hypertension (HTN). Obesity and low birthweight are two risk factors that predispose children to develop HTN during their childhood years or later as adults. Early onset of pre-HTN and HTN increases the lifetime risk for cardiovascular sequelae. Lifestyle modification should be part of the initial recommendations for management of all hypertensive children. In those children requiring pharmacologic therapy, the choice of medication should be guided by the etiology of HTN, the needs of the child and the risk and benefit profiles of the various drug classes. The long-term impact of antihypertensive therapy in children is not known. Concerns regarding the effects of HTN and its treatment on cognitive function are of particular importance in the growing child and warrant further study. Ongoing investigations that offer promise for innovative therapeutic approaches in the future are discussed.

Metabolic syndrome in the pediatric population: a short overview

The metabolic syndrome (MS) in adults is defined as a concurrence of obesity, disturbed glucose and insulin metabolism, hypertension and dyslipidemia, and is associated with increased morbidity and mortality from cardiovascular diseases and type 2 diabetes. Studies now indicate that many of its components are also present in children and adolescents. Moreover, the clustering of these risk factors has been documented in some children, who are at increased cardiovascular risk in adulthood. The MS is highly prevalent among overweight children and adolescents. Identifying these children is important for early prevention and treatment of different components of the syndrome. The first-line treatment comprises lifestyle modification consisting of diet and exercise. The most effective tool for prevention of the MS is to stop the development of childhood obesity. The first attempt at consensus-based pediatric diagnostic criteria was published in 2007 by the International Diabetes Federation. Nevertheless, national prevalence data, based on uniform pediatric definition, protocols for prevention, early recognition and effective treatment of pediatric MS are still needed.The aim of this article is to provide a short overview of the diagnosis and treatment options of childhood MS, as well as to present the relationships between MS and its individual components.

Long-term consequences of drugs on the paediatric cardiovascular system

Many pharmacological and toxicological actions of drugs in children cannot be fully predicted from adult clinical experience or from standard non-clinical toxicology studies. Numerous drugs have direct or indirect pharmacological effects on the heart and are prescribed for children of all ages. Toxicity or secondary effects may be immediate or delayed for years after drug exposure has ceased. Originally, the aim of this review was to compile information on the effect of specific drugs on the post-natal development of the cardiovascular system and to examine long-term follow-up of the use of cardio-active drugs in children. The limited database of published information caused the original question to evolve into an examination of the medical literature for three areas of information: (i) whether vulnerable developmental windows have been identified that reflect the substantial functional development that the cardiovascular system undergoes after birth; (ii) what is known about pharmacological perturbation of development; and (iii) what the likelihood is of drug exposure during childhood. We examined different scenarios for exposure including random, isolated exposure, conditions historically associated with adults, primary or secondary cardiac disease, psychiatric and neurological conditions, asthma, cancer and HIV. Except for random, isolated drug exposures, each category of possible exposure contained numerous drugs known to have either primary or secondary effects on the cardiovascular system or to influence factors associated with atherosclerosis. It is likely that a significant number of children will be prescribed drugs having either direct or indirect effects upon the immature cardiovascular system. A confounding factor is the simultaneous use of over-the-counter medications and herbal or nutraceutical preparations that a patient, parent or guardian does not mention to a prescribing physician. Metabolism is also important in assessing drug effects in children. Differences in body water : body fat ratio, age-related gastrointestinal absorption, distribution, excretion, renal function and drug metabolizing capabilities make it possible for children to have a different metabolite profile for a drug compared with adults. There is little examination of drug effects on the interdependent processes of cardiac maturation and less examination of metabolite effects. It is difficult to identify delayed toxicities in children as these adverse events may take years to manifest with many patients lost to follow-up. Clearly this is an area of study where intermediate endpoints and surrogate markers would be of great benefit. Pharmacogenomics may be useful in providing markers of increased risk or susceptibility. A perspective must be kept in balancing the possibility of a problem with the very real benefits that many children experience from the use of these pharmaceuticals.

Medical management of children with primary hypertension by pediatric subspecialists

Our aim was to characterize medical management of children with primary hypertension (HTN) by pediatric subspecialists. We performed a medical-record review of children < or = 18 years with primary HTN seen at pediatric cardiology or pediatric nephrology clinics at an academic center. Main outcomes were whether treatment decision was in agreement with national guidelines, whether an antihypertensive medication was prescribed, and medication choice. One hundred and eighty children had > or = 1 visit to a pediatric cardiology or nephrology clinic. The majority (83%) of children were pharmacologically managed according to national guidelines. However, only 1/3 children with stage 2 HTN received appropriate antihypertensive therapy from either subspecialty. Only 26 children were prescribed an antihypertensive drug. Children evaluated by pediatric nephrologists were fourfold more likely to receive an antihypertensive than children seen by pediatric cardiologists (29% vs. 7%; p < 0.001). However, all antihypertensive prescriptions were prescribed according to guidelines by both subspecialties. Medical management of children with primary HTN by pediatric cardiologists and pediatric nephrologists is largely consistent with guidelines. However, initiation of appropriate antihypertensive drugs for children with highest severity of HTN is equally poor for both subspecialties. Future studies should explore the factors underlying physicians' reluctance to initiate recommended chronic pharmacologic therapy in children and its associated outcomes.

Evaluation of pediatric patients with mild-to-moderate hypertension: yield of diagnostic testing

OBJECTIVE

Children and adolescents with newly diagnosed hypertension undergo various tests to define the cause and target organ consequences of the elevated blood pressure. We tested the hypothesis that the diagnostic yield of individual components of the currently recommended assessment does not justify performance for all patients with mild-to-moderate hypertension.

METHODS

A retrospective chart review was conducted of patients who were referred between July 2002 and June 2007 for mild-to-moderate hypertension, defined as maximum blood pressure at >or=95% + 20/10 mmHg. The assessment included history and physical examination, nutritional assessment, urinalysis, biochemical and fasting lipid profile, renal ultrasound, echocardiogram, and 24-hour ambulatory blood pressure monitoring.

RESULTS

A total of 249 patients were identified, and charts for 220 (88%) were available for review. There were 156 boys and 64 girls aged 13.3 +/- 4.4 years. BMI was 26.1 +/- 6.7 kg/m(2), and 143 (65%) had a BMI of >or=90%. Results of urinalysis and serum biochemical testing were clinically normal in all cases. Among those with a lipid profile, 59 (42%) had total cholesterol values of >170 mg/dL, and 26 (19%) had severe hypercholesterolemia (>200 mg/dL). Renal sonography revealed findings plausibly associated with hypertension in 14 (8%) patients; 4 (2%) had renovascular abnormalities. Yield of echocardiography was 17%. On ambulatory blood pressure monitoring, 47 (60%) children had systolic readings of >95% at least 20% of the time, and 28 (36%) had diastolic readings of >95% at least 20% of the time.

CONCLUSIONS

For children and adolescents with mild-to-moderate hypertension, on the basis of a cutoff of 5% to 20% abnormal results to define a useful test, the initial evaluation can range from a serum cholesterol level and ambulatory blood pressure monitoring to a panel that consists of a fasting lipid profile, renal ultrasound, echocardiogram, and ambulatory blood pressure monitoring. Additional assessment should be guided by specific clinical features and the nature of the patient population.

Diagnosis of hypertension in children and adolescents based on home versus ambulatory blood pressure monitoring

OBJECTIVE

To investigate the usefulness of home blood pressure measurements in comparison with ambulatory monitoring in the diagnosis of sustained, white-coat hypertension and masked hypertension in children and adolescents.

SUBJECTS AND METHODS

One hundred and two subjects, referred for elevated blood pressure, were assessed with clinic (two visits), home (6 days) and awake ambulatory blood pressure measurements [64 boys, mean age 12.8 +/- 2.9 (SD) years, range 6-18 years].

RESULTS

Office hypertension was diagnosed in 38 subjects, ambulatory hypertension in 31 and home hypertension in 23 (P = 0.07). On the basis of clinic and ambulatory blood pressure, 52% of subjects were normotensive, 20% hypertensive, 18% had white-coat hypertension and 11% masked hypertension, whereas on the basis of clinic and home blood pressure, 55, 15, 23 and 8%, respectively. There was an agreement between ambulatory and home blood pressure in the diagnosis of hypertension in 82 cases (80%). When a 5-mmHg gray zone of diagnostic uncertainty was applied above and below the diagnostic thresholds, there were only eight cases with clinically important disagreement. By taking ambulatory blood pressure as the reference method for the diagnosis of hypertension, the sensitivity, specificity and positive and negative predictive values of home blood pressure were 55, 92, 74 and 82%, respectively, for the diagnosis of white-coat hypertension 89, 92, 70 and 98%, respectively, and for masked hypertension 36, 96, 50 and 93%, respectively.

CONCLUSION

In children and adolescents, there is a reasonable agreement between home and ambulatory blood pressure measurements as diagnostic methods in hypertension. Home blood pressure appears to be a useful diagnostic test in this population, particularly for the detection of white-coat hypertension.

Ambulatory blood pressure monitoring: a versatile tool for evaluating and managing hypertension in children

In recent years, pediatric practitioners have increasingly used ambulatory blood pressure (ABP) monitoring for evaluating blood pressure (BP) abnormalities in children. ABP monitoring in adults is superior to casual BP measurements for predicting cardiovascular morbidity and mortality, and whereas the association with target-organ damage in children is not as definitive, early evidence does seem to parallel the adult data. In addition to confirming hypertension at diagnosis, ABP monitoring may be useful for identifying isolated nocturnal hypertension, characterizing BP patterns, and assessing response to therapeutic interventions. This article reviews current evidence supporting the use of ABP monitoring in children and discusses limitations in our understanding of this technology, specifically focusing on indications for its use and interpretation of the large quantity of data obtained by ABP monitoring.

Blood pressure in children with chronic kidney disease: a report from the Chronic Kidney Disease in Children study

To characterize the distribution of blood pressure (BP), prevalence, and risk factors for hypertension in pediatric chronic kidney disease, we conducted a cross-sectional analysis of baseline BPs in 432 children (mean age 11 years; 60% male; mean glomerular filtration rate 44 mL/min per 1.73 m(2)) enrolled in the Chronic Kidney Disease in Children cohort study. BPs were obtained using an aneroid sphygmomanometer. Glomerular filtration rate was measured by iohexol disappearance. Elevated BP was defined as BP >or=90th percentile for age, gender, and height. Hypertension was defined as BP >or=95th percentile or as self-reported hypertension plus current treatment with antihypertensive medications. For systolic BP, 14% were hypertensive and 11% were prehypertensive (BP 90th to 95th percentile); 68% of subjects with elevated systolic BP were taking antihypertensive medications. For diastolic BP, 14% were hypertensive and 9% were prehypertensive; 53% of subjects with elevated diastolic BP were taking antihypertensive medications. Fifty-four percent of subjects had either systolic or diastolic BP >or=95th percentile or a history of hypertension plus current antihypertensive use. Characteristics associated with elevated BP included black race, shorter duration of chronic kidney disease, absence of antihypertensive medication use, and elevated serum potassium. Among subjects receiving antihypertensive treatment, uncontrolled BP was associated with male sex, shorter chronic kidney disease duration, and absence of angiotensin-converting enzyme inhibitor or angiotensin receptor blocker use. Thirty-seven percent of children with chronic kidney disease had either elevated systolic or diastolic BP, and 39% of these were not receiving antihypertensives, indicating that hypertension in pediatric chronic kidney disease may be frequently under- or even untreated. Treatment with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers may improve BP control in these patients.

Hypertension in children with chronic kidney disease: pathophysiology and management

Arterial hypertension is very common in children with all stages of chronic kidney disease (CKD). While fluid overload and activation of the renin-angiotensin system have long been recognized as crucial pathophysiological pathways, sympathetic hyperactivation, endothelial dysfunction and chronic hyperparathyroidism have more recently been identified as important factors contributing to CKD-associated hypertension. Moreover, several drugs commonly administered in CKD, such as erythropoietin, glucocorticoids and cyclosporine A, independently raise blood pressure in a dose-dependent fashion. Because of the deleterious consequences of hypertension on the progression of renal disease and cardiovascular outcomes, an active screening approach should be adapted in patients with all stages of CKD. Before one starts antihypertensive treatment, non-pharmacological options should be explored. In hemodialysis patients a low salt diet, low dialysate sodium and stricter dialysis towards dry weight can often achieve adequate blood pressure control. Angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers are first-line therapy for patients with proteinuria, due to their additional anti-proteinuric properties. Diuretics are a useful alternative for non-proteinuric patients or as an add-on to renin-angiotensin system blockade. Multiple drug therapy is often needed to maintain blood pressure below the 90th percentile target, but adequate blood pressure control is essential for better renal and cardiovascular long-term outcomes.

Systemic hypertension and proteinuria in childhood chronic renal parenchymal disease: role of antihypertensive drug management

A variety of chronic kidney diseases tend to progress towards end-stage kidney disease. Progression is largely due to factors unrelated to the initial disease, including systemic hypertension and proteinuria. Drugs that block the renin-angiotensin II-aldosterone system, either ACE inhibitors or angiotensin II receptor antagonists, reduce both BP and proteinuria and appear superior to a more conventional antihypertensive treatment regimen in preventing progression to end-stage kidney disease. The most recent recommendations state that the BP goal in children with chronic kidney disease is the corresponding 90th centile for body height, age, and gender. Since satisfactory BP control is often not achieved, the mnemonic acronym DELTAREPROSI was generated to recall the following tips for the practical management of hypertension and proteinuria in childhood chronic renal parenchymal disease: DEfinition of hypertension and Low blood pressure TArget in REnal disease (90th centile calculated by means of simple formulas), potential of drugs inhibiting the REnin-angiotensin II-aldosterone system in hypertension and PROteinuria, advantages of SImplified treatment regimens and escalating the doses every SIx weeks.

Effects of antihypertensive drugs on blood pressure and proteinuria in childhood

BACKGROUND

Historically, there have been few drug trials for antihypertensive treatment in childhood and recommendations have been extrapolated from data obtained in adulthood. During the last decade an increased awareness of the risks of childhood hypertension stimulated clinical trials of antihypertensive agents in children.

OBJECTIVE

The aim of this article is to systematically review the studies published between 1995 and 2006 that deal with the effect of antihypertensive drugs on childhood hypertension or proteinuria.

METHODS

Medline, Current Contents, personal files and reference lists were used as data sources.

RESULTS

Fifty-two out of 79 initially found reports were excluded. Consequently 27 articles were retained for the final analysis. The blood pressure reduction was similar with angiotensin-converting enzyme inhibitors (10.7/8.1 mmHg), angiotensin II receptor antagonists (10.5/6.9 mmHg) and calcium-channel blockers (9.3/7.2 mmHg). In addition angiotensin-converting enzyme inhibitors (by 49%) and angiotensin II receptor antagonists (by 59%) significantly reduced pathological proteinuria.

CONCLUSIONS

The blood pressure reduction of angiotensin-converting enzyme inhibitors, angiotensin II receptor antagonists and calcium-channel blockers is almost identical. In children with pathological proteinuria angiotensin-converting enzyme inhibitors or angiotensin II antagonists are superior to calcium-channel blockers.

Changing relationship between home and office blood pressure with increasing age in children: the Arsakeion School study

BACKGROUND

Home blood pressure (HBP) monitoring is being used in children. However, there is no information on the relationship between HBP and office measurements (Office BP (OBP)) in this population.

METHODS

This school-based study investigated the effect of age on the difference between HBP and OBP in 765 healthy subjects aged 6-18 years (mean age 12 +/- 3 (SD years)). HBP (3 days, 12 readings) and OBP (2 visits, 6 readings) were measured using electronic devices validated in children (Omron 705IT).

RESULTS

Average OBP was slightly lower than HBP by 0.6+/- 7.0 mm Hg (95% confidence intervals (CI) 0.1, 1.1, P=0.01) systolic and 1+/- 6 mm Hg (95% CI 0.7, 1.6, P<0.0001) diastolic, whereas pulse rate was higher in the office by 7+/- 10 beats/min (95% CI 6.2, 7.6, P<0.0001). Age was significantly correlated with the OBP-HBP difference (r = 0.13/0.24 for systolic/diastolic, P< 0.001). In the younger children (6-12 years), both diastolic and systolic HBP were higher than OBP, whereas pulse rate was higher in the office. In older children and adolescents, the BP difference was eliminated whereas the pulse rate difference was reduced but remained significant. These changes with age were similar in boys and girls.

CONCLUSIONS

In the pediatric population OBP appears to be higher than HBP. This difference is reduced with advancing age and eliminated after the age of 12 years. These data should be taken into account in the assessment of HBP in children and adolescents.

Prescription of drugs blocking the renin-angiotensin system in Italian children

Little is known about the prescription pattern of antihypertensive drugs for children with impaired kidney function. We have therefore documented the use of antihypertensive drugs in this patient group by evaluating the Italian pediatric population-based registry of patients with chronic kidney disease on conservative treatment (ItalKid) from 1995 to 2003. In 1995, prescriptions written for antihypertensive drugs for use by children were approximately equally divided among drugs blocking the renin-angiotensin system and calcium channel blockers (38 vs. 43% of all prescriptions), followed by beta-blockers and diuretics (15 and 4%, respectively). During subsequent years the proportion of prescriptions for drugs blocking the renin-angiotensin system increased (2003: 61%; p<0.001) and that of calcium channel blockers decreased (2003: 18%, p<0.001). In 1995, blockers of the renin-angiotensin system were prescribed, either as monotherapy or in combination, in 53% of the patients, but the relative frequency of the patients prescribed these drugs increased up to 83% in 2003 (p<0.0005). In conclusion, physicians caring for Italian children with impaired kidney function are increasingly prescribing drugs blocking the renin-angiotensin system.

Hypertension in children and adolescents

Hypertension is one of the most common health problems in the United States and a powerful independent risk factor for cardiovascular and renal disease. Until recently, the incidence of persistent hypertension in children has been low, with a range of 1% to 3%. Recent data indicate that over the last decade, however, average blood pressure levels have risen substantially among American children. Obesity and other lifestyle factors, such as physical inactivity and increased intake of high-calorie, high-salt foods, are thought to be responsible for this trend. Hypertension in children is currently recognized as an important health issue. There is increasing evidence that hypertension has its antecedents during childhood, because adult blood pressure often correlates with childhood blood pressure. Hypertension in children also is viewed as a significant risk factor for the development of cardiovascular disease in adulthood.

Agreement on reporting of ambulatory blood pressure monitoring in children

The use of ambulatory blood pressure monitoring (ABPM) can improve the accuracy of paediatric BP measurement and may better correlate with end-organ injury than office BP measurement. However, the interpretation of ABPM may be influenced by several variables. We sought to ascertain the agreement among three paediatric nephrologists when reporting 92 ABPM sessions performed on patients aged 5 to 18 years. All three nephrologists were in agreement on the presence or absence of hypertension in 64% of cases. They were less likely to concur about records where hypertension was borderline or if the ABP record contained fewer BP readings. These results highlight the need for evidence-based consensus regarding the interpretation of ABPM in children.