Twenty-four-hour ambulatory blood pressure monitoring in young children

 Twenty-four-hour ambulatory blood pressure monitoring (ABPM) has many advantages for the diagnosis and follow-up of hypertension at all ages. This technique has so far not been documented as applicable to the very young. We studied the feasibility of ABPM in 61 healthy children and in 40 patients with renal diseases and/or hypertension, aged less than 6 years. A satisfactory ABPM profile (recording time = 24 h and >30 good recordings) was obtained in 77% of the healthy children. The mean number of good blood pressure (BP) measurements per 24 h increased with age from 46 (3–4 years) to 58 (6 years). The mean (±SD) systolic and diastolic BPs of healthy 3- to 6-year-old children (n = 47) were 110±5/67±5 mmHg during the day-time and 100±5/58±5 mmHg at night. In addition to the nocturnal decrease in BP, ABPM detected a second, day-time dip in BP during bed rest after lunch. Ninety percent of patients with renal disease and/or hypertension had successful ABPM recordings for 24 h, with an age-dependent increase in the mean number of reliable readings from 34 (< 2 years) to 48 (4 years). In 5 of 10 children with hypertensive results obtained by casual BP measurements, elevated BP was not confirmed by ABPM. We conclude that ABPM is a useful tool for the diagnosis and evaluation of hypertension in children under 6 years of age. Received March 5, 1996; received in revised form and accepted May 6, 1997     

Twenty-four-hour ambulatory blood pressure monitoring in infants and toddlers

During the past several years, 24-hour (24-h) ambulatory blood pressure monitoring (ABPM) has become a useful tool for the diagnosis and management of children and adolescents with elevated blood pressure (BP). Some reports have also provided blood pressure nomograms for particular devices. However, there are very few reports of the use of this method in very young children. In our study we investigated the applicability of ABPM in 97 healthy infants and toddlers, aged from 2 to 30 months. A satisfactory ABPM profile was obtained in 86.6% of the children, with an average of 75.0% satisfactory BP recordings. The mean ± SD systolic and diastolic BP of healthy infants and toddlers was 99±12/62±12 mmHg during the daytime and 95±11/57±10 mmHg during the night, with no gender difference being observed. The 24-h mean ± SD systolic and diastolic BP, which may be a more appropriate measure of BP in this particular age group, was found to be 97±12/59±11 mmHg. We also confirmed the increase in systolic and diastolic BP with increased height (length). There was only a slight nocturnal decrease in BP. We conclude that this method is applicable for the assessment of blood pressure in very young children.     

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 ≤ 0.001). However, the frequency of hypertension for nighttime systolic BP was significantly increased when ABPM criteria were applied (p ≤ 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 ≥50% were evaluated (p ≤ 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.     

维持性血液透析患者透析间期血压节律影响因素的分析

目的 观察维持性血液透析患者透析间期血压节律可能存在的异常并讨论其影响因素。 方法 选择44例维持性血液透析患者，均于透析间期(透析前1 d)进行24 h动态血压监测，根据动态血压监测结果将患者分为3组：非高血压组、高血压控制组及高血压未控制组。监测或评估3组患者的血红蛋白(Hb)、血肌酐(Scr)、Kt/V、血清钙(Ca)、磷(P)、全段甲状旁腺素(iPTH)、透析间期体质量增加(IDWG)、Morisky依从性评分等。对相应的指标进行统计分析，筛选出影响血压节律的因素。 结果 （1）动态血压相关参数包括夜间血压下降率、收缩压和舒张压的夜间下降率、动态动脉硬化指数(AASI)、杓形血压比例在3组之间的差异无统计学意义。高血压未控制组的24 h平均脉压比其他两组高[（80.06±13.41）比（53.00±7.73）、（57.85±21.97） mm Hg，均P < 0.01]。（2）3组患者血压曲线均呈现“两峰一谷”的表现，高血压未控制组夜间血压下降不明显。（3）夜间收缩压下降率与血iPTH呈负相关(r = －0.349， P = 0.024)。（4）44例患者中的全部10例杓型血压节律者的AASI与夜间舒张压下降率呈负相关(r = －0.748，P = 0.013)。 结论 维持性血液透析患者夜间血压下降与甲状旁腺素及血管硬化程度有关。     

慢性肾脏病患者血压昼夜节律异常的研究

目的 观察慢性肾脏病(CKD)患者24 h血压动态变化，探讨昼夜节律异常与肾功能损害的关系。方法 随机选择本院肾脏科CKD患者236例，高血压科原发性高血压住院患者43例。病例分组:正常对照组(NC)14例；原发性高血压组(EHC)43例；CKD血压正常组(NCKD)130例；CKD伴血压升高组(HCKD)106例。动态血压监测(ABPM)采用携带式的动态血压检测仪，ABP Report Mangement System Version 1.03.03进行数据分析。夜间血压下降率:(白昼平均值-夜间平均值)/白昼平均值，下降率≥10%，称勺型血压；<10%，称非勺型血压。结果 在血压正常的患者中，NCKD组的平均夜间收缩压和舒张压数值均高于NC组[(111.2±10.8)比 (91.6±7.5)，(68.7±9.5) 比 (56.2±4.6)mm Hg，P < 0.05]；而日间收缩压和舒张压无明显差异。在高血压患者中，HCKD组患者夜间收缩压和舒张压数值均高于EHC组[(141.9±16.5) 比(118.6±16.4)， (84.5±10.6)比(73.0±11.1)mm Hg， P < 0.05]。CKD患者无论血压正常或升高，其心率均较其对照组明显加快，尤其是夜间心率无明显下降。NCKD组、HCKD组与NC组、EHC组相比，夜间收缩压和舒张压下降数值较小，尤其是CKD伴血压升高组，呈典型的非勺型血压模式。NC组血压节律消失者占7.14%，EHC组为37.2%，NCKD组为70.0%，HCKD组为81.6%。结论 CKD患者无论血压正常或升高，夜间收缩压和舒张压下降减少或消失，呈典型的非勺型血压；血压昼夜节律异常率明显高于原发性高血压患者。在积极降低血压值的同时，还需降低血压负荷和调整血压昼夜节律，以延缓肾功能恶化。     

慢性肾脏病患者24h动态血压与中医辨证分型的相关性研究

目的探讨慢性肾脏病（chronic kidney disease,CKD）患者动态血压变化与中医辨证分型的相关性。方法收集湖北省中医院符合CKD2～4期诊断标准的门诊及住院患者145例。对入组患者进行24h动态血压监测,根据血压变化情况,分为昼夜平均血压正常组（血压≤130／80mrnHg）,昼夜平均血压升高组（血压≥131／81mmHg）,日间平均血压升高组（血压〉135／85mmHg）,夜间平均血压升高组（血压〉125／75mmHg）;并根据临床表现,对患者进行中医辨证,分为本虚证及邪实证。观察中医各证型在血压正常组和血压升高组中的分布情况。结果①昼夜平均血压正常组的本虚证型分布以脾肾阳虚为主,邪实证型以血瘀证为主;昼夜平均血压升高组的本虚证型以气阴两虚为主,邪实证型以湿浊证为主;②在动态血压从日间升高到夜间升高的过程中,本虚证型中阴阳两虚证型逐渐上升,邪实证型中浊毒证型逐渐上升;③随着24h动态血压升高,本虚证型中,阴阳两虚证型逐渐上升;邪实证型中,浊毒证逐渐上升。结论动态血压变化在一定程度上反映中医正虚邪实的证候变化规律。     

糖耐量低减患者动态血压与尿白蛋白排泄率的关系

目的 探讨糖耐量低减(IGT)患者尿白蛋白排泄率(UAE)与不同血压指标的关系。方法 对44例IGT患者均进行动态血压(ABPM)监测,心血管自主神经功能测试,UAE测定。结果 与UAE正常组比较,UAE增高组ABPM多项指标增高,夜间血压降低幅度减少,24小时血压曲线平坦。UAE与夜间舒张压(DBP)、收缩压(SBP)负荷、DBP负荷、24hDBP以及24hSBP呈显著正相关,与昼夜血压差值呈显著负相关。结论 UAE增高的IGT患者已经开始出现血压的异常改变。     

Clinical uses of ambulatory blood pressure monitoring

Traditional office measurements of blood pressure are commonly used to initiate and monitor therapy for hypertension, but these measurements are limited in their ability to provide information from the patient's normal work or play environment and do not include data from the overnight period when the patient is asleep. Thus, much potentially important information is lost. The ambulatory blood pressure monitor offers the attractive advantage of providing multiple blood pressure measurements from a subject's normal environment during his normal activities, thereby revealing important patterns of blood pressure in health and in illness. Further, the results of ambulatory monitoring have an excellent correlation with end-organ damage and these data can be obtained in a very short time period. This review will discuss the chronobiology of blood pressure, the clinical uses of the ambulatory blood pressure monitor in health and in disease, including the patterns of blood pressure identified, correlation with end-organ damage and its uses in clinical trials of antihypertensive medications; the experience in children with this technology will also be discussed.     

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.     

Utility of ambulatory blood pressure monitoring in children and adolescents

Diagnosis of hypertension is critically dependent on accurate blood pressure measurement. “Accurate” refers to carefully following the guidelines for blood pressure measurement laid out for children and adults to minimize observer and subject errors that commonly occur in clinical blood pressure measurement. Accurate blood pressure measurement is more important in children and adolescents as the misdiagnosis of hypertension may have a life-long adverse impact on insurability and employment. Automated blood pressure measurement offers multiple advantages in achieving high-quality blood pressure determinations by reducing observer errors. The most commonly used form of automated blood pressure measurement is 24-h ambulatory blood pressure measurement (ABPM). Information on ABPM in children has grown exponentially over the last decade. Normative data exists for diagnosis of hypertension in children using ABPM including a novel method for determining normal values with the LMS method. There is further information about the utility of different determinants of 24-h blood pressure such as dipping status, morning surge and blood pressure load. ABPM has been able to detect significant differences in blood pressure in many disease states in children including chronic renal failure, polycystic kidney disease, solitary functioning kidney, and after renal transplantation. Increasingly nonambulatory automated blood pressure determinations have been used in management of hypertension in children. Although nonambulatory automated readings lack information about nocturnal blood pressure or blood pressure during daily activity, studies have suggested that home automated blood pressure measurements are a helpful adjunct to the usual office blood pressure reading.     

Blood pressure and renal function in autosomal dominant polycystic kidney disease

  The purpose of this study was to identify hypertension in children and adolescents in an early stage of autosomal dominant polycystic kidney disease (ADPKD) by the application of ambulatory blood pressure monitoring (ABPM) over 24 h; 32 children and adolescents (mean age 12.3±4.7 years) were examined. The diagnosis was based on family history and ultrasound examination. In 21 children ADPKD was confirmed by molecular genetic analysis. At the time of the study, 45% patients were asymptomatic and all had glomerular filtration rates (GFRs) ≥65 ml/min per 1.73 m². By ABPM, 11 patients (34%) were defined as hypertensive (systolic or diastolic blood pressure >95th percentile), including 4 with an exclusive nocturnal hypertension. Of 7 patients with daytime hypertension, 4 had normal blood pressure by casual measurements. The nocturnal dip in blood pressure was reduced in 2 patients. Blood pressure correlated with renal size, but not with GFR, concentrating capacity, proteinuria, and plasma renin activity. The study reveals an early trend for increased blood pressure in children with ADPKD, requiring close supervision. Received October 18, 1996; received in revised form and accepted March 11, 1997     

Pathomechanisms and the diagnosis of arterial hypertension in pediatric renal allograft recipients

Arterial hypertension is common in pediatric renal allograft recipients. While the causes are multifactorial, including chronic graft rejection, immunosuppressive therapy, and renal vascular disorders, the effect of hypertension on renal allograft function is detrimental. As in adults, if not treated early and aggressively, hypertension may lead to cardiovascular damage and graft failure. Pathophysiological changes in the arteries and kidney after renal transplantation and the impact of receptor regulation have not been studied extensively in children. For identifying children with hypertension following renal transplantation casual blood pressure measurements do not accurately reflect average arterial blood pressure and circadian blood pressure rhythm. Ambulatory 24-h blood pressure monitoring should regularly be applied in transplant patients. The purpose of this review is to analyze pathophysiological aspects of risk factors for arterial hypertension and underline the importance of regular blood pressure monitoring and early therapeutic intervention.     

IgA肾病患者血压节律及其与临床病理指标的关系

目的 探讨IgA肾病患者血压昼夜节律与临床病理指标的关系.方法 采用横断面调查研究.选择2009年3月至8月在IgA肾病数据库登记的原发性IgA肾病患者,收集临床病理资料,并通过动态血压监测IgA肾病患者血压昼夜节律情况.用(日间血压平均值-夜间血压平均值)/日间血压平均值判断血压昼夜节律状况.比较血压节律正常组及异常组的临床病理指标.结果 共93例患者完成动态血压监测并纳入分析.其中68例(73％)血压节律消失,在慢性肾脏病(CKD)1期、2期及3期以上组血压节律消失的比例分别70％、70％及81％,3组间差异无统计学意义(P=0.587).非勺型血压在血压正常组与高血压组比例分别为69％和77％(P=0.373).血压节律消失与年龄、性别、血压、蛋白尿、肾功能以及肾脏病理损伤程度无相关.在随访时间超过12个月的54例中,非勺型血压组eGFR下降速率虽快于勺型血压组,但差异无统计学意义(P=0.329)；在其中29例并发高血压患者中,非勺型血压组eGFR下降速率快于勺型血压组,且差异有统计学意义[(-6.79±11.58)比(-0.34±1.74)ml·min-1·(1.73 m2)-1·年-1,P=0.019].结论 IgA肾病早期即可出现明显的血压节律消失.IgA肾病伴高血压患者的血压节律消失可能是影响肾功能进展的危险因素.     

Direct comparison of repeated same-day self and ambulatory blood pressure monitoring

BACKGROUND AND AIM: The relative roles of self and ambulatory blood pressure monitoring (self BPM, ABPM, respectively) have yet to be clearly defined despite accumulating evidence of self BPM benefits, particularly in hypertension management. In particular, measurements comparable to ABPM have been documented with self-measurement, usually twice daily over one or more days. Nevertheless, ABPM offers a series of recordings performed throughout the day that can be invaluable during drug treatment. Consequently, this study evaluated 18 normotensive and 79 hypertensive patients, including 21 not taking hypotensive agents, and measured their blood pressure at least every 2 h while they were also undergoing ABPM. METHODS AND RESULTS: Self-measurement was performed between five and 12 times during the day with 77% of subjects preferring self BPM rather than daytime ABPM. When compared with the closest ABP measurement, mean systolic and diastolic pressures were not significantly different throughout the day in both normotensive and hypertensive patients. However, a comparison of a series of ABPM hourly averages (three readings performed closest to the respective self BPM reading) throughout the day in all hypertensive subjects found ABPM readings to be slightly but significantly lower (3.3 systolic, 2.2 mmHg diastolic; P < 0.05). CONCLUSION: It is concluded that multiple self-measurements throughout the day provides comparable information to daytime ABPM, is preferred by most patients, and should be a cost-effective alternative in the diagnosis and management of hypertension.     

Changes of blood pressure and left ventricular mass in pediatric renal transplantation

Cardiovascular events are among the most frequent causes for long-term morbidity and mortality in children after renal transplantation. The aim of this study was to analyze the effects of post-transplant changes in arterial hypertension, as assessed by 24-h ambulatory blood pressure measurement (ABPM), on myocardial architecture, as assessed by echocardiography. In a retrospective chart review analysis, 39 children were identified in whom 24-h ABPM and echocardiography had been assessed within a 3-month interval after a mean of 4 years post transplantation; 20 repeated pairs of measurements after a mean of 2 years of follow-up were available to analyze the longitudinal effects of post-transplant changes of blood pressure control on left ventricular mass index (LVMI). Arterial hypertension (59%) and left ventricular hypertrophy (50%) were highly prevalent in children after renal transplantation. Renal allograft function and number of antihypertensive medications, but not ABPM variables, were correlated with LVMI at the initial observation. However, at repeat assessment, a significant correlation between ABPM and LVMI was found. In the longitudinal assessment, left ventricular remodeling was dependent on change of dosage of cyclosporine and interval changes of blood pressure levels. Hence, control of blood pressure correlates with changes of LVMI in children with renal allografts. These results clearly underline the importance of blood pressure control for the maintenance of the myocardial architecture.E. Kitzmueller and A. Vécsei contributed equally to this work     

Ambulatory blood pressure monitoring after recovery from hemolytic uremic syndrome

The outcome of acute renal failure due to diarrhea-associated hemolytic uremic syndrome (D+ HUS) is generally predicted to be good. However, there are only a few long-term observations with detailed reports on long-term sequelae. Specifically, adequate long-term blood pressure (BP) evaluations are scarce. The present study evaluated BP in pediatric patients after childhood D+ HUS. The study group comprised 28 patients (20 males) aged 6-23.5 years (median 10.1 years). All patients had a history of D+ HUS at a median age of 1.1 years (range 0.5-6 years). Based on the duration of oliguria and/or anuria, the primary disease was classified as mild (n=6), moderate (n=6), or severe (n=16). The BP in these patients was studied at a median time of 8.4 years (range 2.3-22.9 years) after manifestation of D+ HUS by means of office BP measurements and 24-h ambulatory BP monitoring (ABPM) using a Spacelabs 90207 oscillometric monitor. Measurements were compared with normal values of published standards for healthy children and adolescents. Conventional office BP measurements were above the 95th percentile in 1 patient. By ABPM, 2 patients were diagnosed to have mean systolic daytime and nighttime values in the hypertensive range, and systolic and diastolic hypertension was confirmed in the first patient. All these patients had a severe form of D+ HUS in the past. By applying ABPM, BP anomalies were detected in 5 additional patients. Elevated systolic BP loads were found in 4 patients, and daytime systolic and diastolic hypertension in the other 1. At the time of the study, 2 of them were classified as "recovered." The late outcome of D+ HUS may be worse than anticipated. BP anomalies as long-term sequelae of D+ HUS could be identified by ABPM but not by office BP measurements. These findings may represent an isolated sign of residual renal disturbance.     

Effect of ramipril on ambulatory blood pressure and albuminuria in renal hypertension

Inhibition of the angiotensin-converting enzyme (ACE) exerts a renoprotective effect in adult patients with chronic kidney disease. We evaluated prospectively changes in blood pressure (BP), protein excretion and renal function after administration of the long-acting ACE inhibitor ramipril as monotherapy during 6 months in 14 moderately hypertensive children aged 5–18 years with various nephropathies. Four patients initially had a decreased glomerular filtration rate (GFR below 60 ml/min/1.73 m²). BP was evaluated by ambulatory 24-h monitoring. After 2 weeks of treatment by oral ramipril (1.5 mg/m² once daily), mean values of systolic and diastolic 24-h ambulatory BP fell by more than 5 mmHg in nine patients. In eight patients the dose was doubled. At the end of the study systolic BP was below the 95th percentile in 9 and diastolic BP in 13 patients. The initially reduced nocturnal dip increased significantly. Of 11 patients with an increased albumin excretion (median 1.3 g/g creatinine), 6 responded to ramipril by a median reduction of 78% (range 24–83%), whilst in 5 albuminuria increased (median +19%). GFR was well preserved and no other adverse effects from the drug were noted. The study demonstrates that ramipril is an efficacious antihypertensive agent in children with renal hypertension. It is well tolerated, even in mild renal insufficiency. In addition, the drug has a persistent antiproteinuric action in about half of the patients contributing to conserve renal function. Received: 4 August 1999 / Revised: 27 March 2000 / Accepted: 29 March 2000     

维持性血液透析患者血压晨峰和心脑血管疾病关系的临床观察

目的探讨维持性血液透析(maintenance hemodialysis,MHD)患者血压晨峰与心脑血管疾病发生的关系。方法选取四川省眉山市人民医院肾内科242例MHD患者采用动态血压监测仪记录24 h血压,根据血压晨峰分为血压晨峰组(44例)和非血压晨峰组(198例)。采集2组患者相关的研究数据,记录发生的心脑血管疾病,随访3年,比较2组患者一般资料、心脑血管疾病发生率及病死率。结果①2组患者24 h平均收缩压(24hSBP)比较差异有统计学意义(P0.05),血白蛋白、血红蛋白、血钙、血磷和24 h平均舒张压(24hDBP)比较差异无统计学意义(P0.05)。②血压晨峰组的24hSBP、白天平均收缩压(dSBP)、夜间平均收缩压(nSBP)、QT离散度、左心室质量指数分别为(152±14)mmHg、(158±10)mmHg、(124±12)mmHg、(56.2±14.6)、(132.8±4.0)g/m~2,与非血压晨峰组比较差异有统计学意义(P0.05);晨起时2hSBP、24 h平均脉压(24hPP)、动脉内膜-中膜厚度分别为(168±17)mmHg、(62.5±12.6)mm-Hg、(1.18±0.32)mm,与非血压晨峰组比较,差异有统计学意义(P0.01);2组患者24hDBP、dDBP、nDBP、夜间最低DBP和晨起时2hDBP比较,差异无统计学意义(P0.05)。③血压晨峰组的心脑血管疾病发生率(63.6%)及病死率(27.3%)显著高于非血压晨峰组(22.7%,8.1%)(P0.01)。结论 MHD患者存在血压晨峰现象,血压晨峰与MHD患者心脑血管疾病密切相关,可能是MHD患者心脑血管疾病的独立危险因素。     

Effect of recombinant human erythropoietin therapy on ambulatory blood pressure and heart rate in chronic haemodialysis patients.

Systemic hypertension as assessed by causal blood pressure measurements is a frequently reported side-effect of recombinant human erythropoietin (rHuEpo) treatment. We investigated the effect of rHuEpo treatment on the 24-h ambulatory blood pressure and heart rate profiles of 13 chronic haemodialysis patients. After 3-4 months of rHuEpo therapy it was found that the mean haematocrit had increased from 24.5 +/- 1.0% to 32.0 +/- 1.1% (P less than 0.005), while body-weight and control of uraemia as assessed by routine laboratory data remained unchanged. Despite gradual and incomplete correction of anaemia by use of low doses of rHuEpo, increases in the ambulatory systolic and diastolic blood pressure were found. The greatest increases affected day-time systolic blood pressure and night-time diastolic blood pressure, and these increases were significant (P less than 0.05). As a result, pulse pressure increased during day-time (P less than 0.05) while the night-time decline in diastolic blood pressure disappeared. An increase in peripheral resistance after partial correction of renal anaemia might explain these observations. rHuEpo therapy increased the percentage of abnormal ambulatory blood pressure measurements (defined as systolic blood pressure greater than 140 mmHg and/or diastolic blood pressure greater than 90 mmHg) from 33% to 52% (P less than 0.05) while in contrast, mean casual prehaemodialytic and posthaemodialytic blood pressure values remained unchanged. We conclude that changes in 24-h blood pressure profiles should be carefully assessed by ambulatory blood pressure monitoring in haemodialysis patients treated with rHuEpo, since these changes are likely to be missed when only causal blood pressures are measured.     

Repeated ambulatory blood pressure monitoring in adolescents with mild hypertension

The reproducibility of serial measurements of ambulatory blood pressure monitoring (ABPM) has not been well explored in children. We performed 24-h ABPM in 59 subjects (38 boys) aged 8-19 years with repeatedly elevated casual blood pressure (BP). According to the results of ABPM, the individuals were divided into a hypertensive group (mean 24-h systolic or diastolic BP >95th percentile for height, n=28) and a normotensive group (n=31). No antihypertensive agents were given. Both groups were reexamined after 1 year. In the hypertensive group, systolic and diastolic BP dropped significantly by an average of 2.1-4.5 mmHg when measured either during the daytime or over 24 h, but not at nighttime. In the normotensive group, only small BP changes were observed except for a significant increase in systolic BP at night. At the repeat examination after 1 year, 54% of the originally hypertensive subjects were defined as normotensive and 23% of the originally normotensive subjects as hypertensive. The study indicates that a single ABPM measurement is not sufficient for definitive classification of young individuals into hypertensives or normotensives.