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.     

Blood volume monitoring to achieve target weight in pediatric hemodialysis patients

Achieving dry weight during hemodialysis (HD) while minimizing symptoms is critical for optimizing patient outcome by preventing chronic fluid overload, hypertension, and cardiomyopathy. Dry weight changes frequently in children because of growth and development and waxing and waning of appetite. We have previously shown non-invasive hematocrit monitoring (NIVM) helps to decrease intradialytic symptoms, while still achieving target dry weights in children receiving chronic HD. In the current study, we prospectively evaluated an NIVM-guided ultrafiltration (UF) management algorithm to determine target dry weight in nine pediatric patients (mean age 16.6±2.8 years, mean weight 41.6±11.1 kg). Use of NIVM could potentially lead to overly aggressive UF with increased interdialytic symptoms, post treatment thirst, and interdialytic weight gain (IDWG). To evaluate the effectiveness of our NIVM UF algorithm, we studied the effect of three different NIVM-guided UF models (100%, 90%, and 80% UF models) on intradialytic and interdialytic symptoms, pre-/post-treatment blood pressure (BP), and percentage IDWG. To assess interdialytic symptoms, patients completed two questionnaires, one for each day between treatments. No statistically significant difference was seen between the three UF models with respect to intradialytic or interdialytic symptoms, pre-/post-HD BP, or percentage IDWG. Only one of nine patients received non-ACEI chronic antihypertensive medication, yet all patients had pre- and post-HD BP <95th percentile for age and height. The current study suggests that routine determination of target dry weight using NIVM and aiming for 100% UF helps to achieve the target dry weight, reduces both the risk of chronic fluid overload and the need for antihypertensive medication, and does not lead to increased intra- or interdialytic symptomatology in pediatric patients treated with chronic HD.     

Ambulatory blood pressure monitoring in paediatric patients treated by regular haemodialysis and peritoneal dialysis

Ambulatory blood pressure monitoring (ABPM) has been shown to be more representive of blood pressure (BP) levels than casual BP measurements in adult patients treated by haemodialysis (HD). In this study we compared ABPM using the oscillometric SpaceLabs 90207 monitor with casual BP measurements in 35 paediatric patients [17 treated by peritoneal dialysis (PD) and 18 by DH]. Heart rate and plasma concentrations of atrial natriuretic peptide were also measured. No correlations were found between ABPM and casual BP measurements, except for systolic day-time BP in PD patients (r=0.63). Seventy percent of PD and 33% of HD patients were regarded as hypertensive when evaluated by ABPM, while casual BP measurements demonstrated hypertension in 47% (P<0.05) of PD patients and in 44% (NS) of HD patients. One-third of patients were reclassified by ABPM either from normotensive to hypertensive (7/19) or from hypertensive to normotensive (5/16). BP assessed by ABPM was higher in PD than in HD patients. The physiological decline of BP at night was significant and more prouounced in PD than in HD patients. In HD patients day-time BP did not differ between the 1st and the 2nd interdialytic day, but increased in the night hours before the following dialysis session. A positive correlation was found between day-time BP and pre-dialysis plasma atrial natriuretic peptide in both treatment groups. In conclusion this study demonstrates that casual BP recordings are not representative of average BP in dialysed paediatric patients. ABPM is useful in the diagnosis and treatment of hypertension in children with endstage renal disease.     

Blood pressure control in pediatric hemodialysis: the Midwest Pediatric Nephrology Consortium Study

Hypertension is frequent in pediatric patients receiving dialysis, with an especially high rate reported in children on hemodialysis (HD). We performed the present study to assess blood pressure (BP) status and identify risk factors for poor BP control in children on maintenance HD. One month’s dialysis records were collected from 71 subjects receiving HD in ten dialysis units participating in the Midwest Pediatric Nephrology Consortium (MWPNC). For each HD session, data on pre- and posttreatment weights and BPs were recorded. Hypertension, defined as mean BP ≥ 95th percentile, was found in 42 (59%) subjects. Eleven subjects (15.5%) had prehypertension, defined as mean BP between the 90th and 95th percentiles, while 18 subjects (25.3%) had normal BP (<90th percentile). BP significantly decreased at the end of a dialysis session; however, only 15 of 42 hypertensive subjects (35%) normalized their BP. Hypertensive subjects were younger (p = 0.03), had higher serum phosphorus (p = 0.01), and had more elevated posttreatment weight above estimated dry weight (p = 0.02). Logistic regression showed that younger age (p = 0.02) and higher serum phosphorus (p = 0.02) independently predicted hypertensive status. In conclusion, this study emphasizes the difficulty of BP control in pediatric HD patients. Especially poor BP control was found in younger children; those patients who do not reach their posttreatment weight goals, perhaps reflecting their hypervolemic state; and those who have higher serum phosphorus levels.     

Blood pressure profile in renal transplant recipients and its relation to diastolic function: tissue Doppler echocardiographic study

Hypertension is a common complication after renal transplantation and is associated with increased risk of cardiovascular disease. The aim of the current study was to investigate the diurnal blood pressure pattern and its relation to structural and functional cardiac changes in renal transplant recipients. Sixty-six stable renal transplant patients (34 female, 32 male), aged 7 to 25 years (mean 17.4 ± 4.3 years) were enrolled in this study. Cardiac function assessed by tissue Doppler echocardiography and blood pressure measurement performed using both the ambulatory and the casual method. Hypertension was demonstrated in 57% of recipients by the casual method and in 75.7% by ambulatory blood pressure monitoring (ABPM). The efficacy of BP control among patients on antihypertensive drugs was 60%. The prevalence of non-dipping was 73%. There was significant inverse correlation between systolic or diastolic day-time or night-time BP index and post-transplant duration (p < 0.001, r =−0.386), but no correlation between ABP parameters and BMI, gender, and eGFR. There was a significant relationship between all ABP parameters and left ventricular mass index (LVMI) (p = 0.025–0.007, r = 0.28–0.38). LVMI was significantly higher in hypertensive than in normotensive cases (p = 0.034). There was no difference in diastolic function between hypertensive and normotensive patients or between patients with and without left ventricular hypertrophy (LVH). In conclusion, our study showed the advantage of ABPM over the casual method of diagnosis of hypertension. LVH is common in transplant patients and is likely associated with arterial hypertension. Hypertension and LVH cannot differentiate transplant patients with diastolic malfunction.     

Ambulatory blood pressure monitoring in healthy children with parental hypertension

The aim of this study was to compare ambulatory blood pressure monitoring (ABPM) parameters in offspring with at least one hypertensive parent (HP) to offspring with normotensive parents (NP) and to determine whether gender of parent or child might influence the association between parental hypertension and blood pressure (BP). Eighty-nine healthy children (mean age 11.1 ± 3.9 years) with HP and 90 controls (mean age 10.5 ± 3.1 years) with NP were recruited. Age, gender, and height did not differ between the two groups, whereas children of HP had higher weight, body mass index (BMI), and waist circumference compared with healthy controls. No difference was found in casual BP between the two groups. In contrast, during ABPM daytime and nighttime mean systolic and diastolic BP and mean arterial pressure (MAP) standard deviation scores (SDS) were significantly elevated in children with HP. The mean percentage of nocturnal BP decline (dipping) was not significantly different between the two groups. Children with hypertensive mothers had higher daytime systolic and MAP SDS than controls; no such difference was detected for children with hypertensive fathers. Daytime systolic and MAP SDS were significantly elevated in boys with HP compared with boys with NP but failed to be significant in girls. Multiple linear regression analysis showed that parental history of hypertension (B = 0.29) and BMI (B = 0.03) were independently correlated with increase of daytime MAP SDS. Early changes in ambulatory BP parameters were present in healthy children of HP. BP in HP offspring was influenced by the gender of the affected parent and the offspring.     

Serum uric acid is associated with high blood pressure in pediatric hemodialysis patients

Serum uric acid (UA) is positively associated with hypertension (HTN). HTN is common in pediatric patients receiving hemodialysis (HD) and peritoneal dialysis (PD). We assessed the relationship between UA and BP in 63 pediatric dialysis patients by measuring pre-treatment UA levels and BP in HD patients and in-center UA levels and blood pressure (BP) in PD patients. UA levels were similar in both groups [6.8 ± 0.2 (HD) vs. 6.5 ± 0.3 (PD), p = 0.6]. Pre-treatment systolic BP percentile was associated with a high UA level [91.9 ± 2.3 (>6.0 mg/dL) vs. 79.3 ± 5.8 mm Hg (≤6.0 mg/dL), p = 0.01] in HD patients only. There was a negative relationship between UA and dialysis vintage (r = −0.31, p = 0.01). In both groups, there was no relationship between UA and Kt/V. In HD patients, fluid overload was unrelated to UA level [4.2 ± 0.6% (≤6.0 mg/dL) vs. 4.3 ± 0.3% (>6.0 mg/dL), p = 0.9]. Moreover, pre-HD treatment systolic BP percentile correlated with UA (beta 0.36, p = 0.02) independent of volume. UA levels were higher in patients receiving anti-hypertensive medications [6.3 ± 0.2 (No Meds] vs 7.0 ± 0.2 (BP Meds) mg/dL,  p= 0.01]. Finally, there was no relationship between serum UA and normalized protein catabolic rate (r = 0.14; p = 0.4). In summary, serum UA impacts BP in pediatric HD patients, independent of volume, nutritional and weight status.     

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     

Ambulatory blood pressure monitoring in children: a large center’s experience

Ambulatory blood pressure monitoring (ABPM) is well established in adults and is becoming common in children. We reviewed 190 ABPM studies retrospectively (since 1990) to assess the failure rate, and analyzed the data from 97 patients 5–19 years old (1992–1996) to review the experience gained from the use of this technique in children and adolescents. Seventeen percent (32/190) of studies failed. Most children accepted ABPM, provided it was clearly explained in advance. There were differences between day and night readings of systolic blood pressure (BP), diastolic BP, and heart rate. BP did not correlate with height or weight. ”White coat” effect apparently exists in children: clinic systolic BPs were higher than daytime systolic ABPM (no difference in diastolic). Eighty-nine percent (86/97) had an elevated BP load (>30% of readings >95th percentile). The antihypertensive medications of 16% (16/97) of patients were changed after ABPM. The nocturnal fall in BP (expressed as a percentage of the individual mean daytime values) was approximately normally distributed and was independent of age and height. Nocturnal systolic and diastolic dipping were closely correlated. Attenuation of nighttime dipping was observed in children with kidney disease and those with organ transplants. There is a need for normative data for ABPM for North American children. In our study, the technique was useful in selected cases, such as borderline or secondary hypertension, and for therapeutic monitoring when BP control is difficult. Received: 1 March 1999 / Revised: 24 November 1999 / Accepted: 28 November 1999     

Ambulatory blood pressure monitoring and renal functions in term small-for-gestational age children

The aim of this study was to investigate the relationship between birth weight and blood pressure (BP) by means of ambulatory BP monitoring (ABPM) and renal functions in non-obese children who were born small-for-gestational age (SGA) at term. The study group consisted of 39 (19 female, 20 male; mean age 8.8 ± 2.6 years) children born SGA. Their data were compared to those of 27 (13 female, 14 male; mean age 8.2 ± 2.9 years) children born appropriate-for-gestational age (AGA). No difference between SGA and AGA children was observed based on office BP measurements and daytime, nighttime and 24-h ABPM. Seventeen SGA (48.6%) and nine AGA (37.5%) children had a 24-h systolic BP (SBP) load over 25%, and seven of these (5 SGA, 2 AGA) were hypertensive according to mean SBP values. The prevalence of the non-dipping phenomenon in SGA and AGA children was similar. Renal functions were normal and similar in both groups. Three children (2 SGA, 1 AGA) with normal glomerular filtration rate had higher microalbumin excretion and one SGA child had systolic hypertension according to the office BP. Our findings demonstrate that the influence of intrauterine growth restriction on BP is not manifested during the childhood period, and they do not support the existence of a negative relationship between birth weight and BP in children.     

Blood pressure measurements and left ventricular mass index in hemodialysis patients

Left ventricular hypertrophy (LVH) is the most frequent cardiac abnormality in hemodialysis (HD) patients. It is related to cardiovascular diseases and is an important risk factor for mortality in HD patients. Arterial hypertension is an established risk factor for LVH in HD patients. Inferior vena cava (IVC) diameter is a good indicator of circulating fluid volume; hypervolemia is an important pathogenetic factor of hypertension in HD patients. The purpose of our study was to evaluate possible association between LVH, IVC diameter, and different blood pressure (BP) measurements in HD patients. In the present study, 85 HD patients were included. BP was measured with a standard mercury sphygmomanometer before and after the HD session; the average 1‐monthly values of the routine BP measurements were also analyzed. 24‐ and 48‐h ambulatory blood pressure measurements (ABPMs) were performed after the end of HD sessions using a noninvasive ABPM. Average values of systolic and diastolic BP were analyzed separately for the first (HD) and second (interdialytic) day ABPM and for both days together. Using echocardiography, left ventricular mass was measured and left ventricular mass index (LVMI) was calculated. Using ultrasonography, IVC diameter was measured on the interdialytic day. Using multiple regression analysis, we found statistically significant correlations between LVMI and mean monthly postdialysis systolic BP (P < 0.05) and mean 48‐h diastolic BP (P < 0.05). Only longer BP measurements (average 1‐month post‐HD and 48‐h ABPM) were associated with LVMI in HD patients.     

The definition of daytime and nighttime influences the interpretation of ABPM in children

To test if an arbitrary definition of day and night periods that differs to patient-reported awake and sleep periods leads to inaccuracies in interpretation of ambulatory blood pressure monitoring (ABPM). A single-center, retrospective review was performed comparing three different methods to classify day and night periods following a single 24-h ABPM: method A: Patient's record during monitoring; method B: 7:00 am to 11:00 pm day and 11:00 pm to 7:00 am night; method C: 8:00 am to 8:00 pm day and midnight to 6:00 am night. We included 149 studies in 149 children with a mean ± SD age of 13.0 ± 3.4 years. Reported sleep duration was 9.2 ± 1.3 h. Significant differences resulted between three methods for the means of several ambulatory BP parameters including indexed BP values during day, BP load, and nocturnal dipping status. During monitoring [median (range)], 7.5% (0.0–27.5%) readings were misclassified using method B and 0.0% (0.0–20.0%) using method C (p < 0.0001). This misclassification resulted in change of hypertension status for 11.4% (17/149) patients using method B and 9.4% (14/149) patients using method C (p = 0.70). Misclassification of measurements during ABPM can introduce significant errors in its interpretation. The clinical impact of these findings needs further evaluation in larger prospective studies.     

Haemodialysis‐unresponsive blood pressure: Cardiovascular mortality predictor?

AIM: The importance of 'conventional' cardiovascular risk factors in haemodialysis (HD) patients has been questioned following evidence that pre-HD blood pressure (BP) might be inversely related to mortality in contrast to post-HD BP. To evaluate this reverse BP epidemiology in HD patients, HD-induced BP changes were compared with aortic pulse wave velocity (PWV), an independent predictor of cardiovascular mortality. METHOD: Aortic PWV was evaluated in a limited care HD cohort, all of whom were asymptomatic of cardiovascular disease. RESULTS: Of 47 limited care patients, 45% were classified as HD responsive, with a 17% fall in mean arterial pressure compared with a 6% increase in the HD-unresponsive group. While there were no significant differences between the two groups in traditional vascular disease risk factors or interdialytic weight loss, PWV was significantly elevated in the HD-unresponsive group (12.9 +/- 2.7 compared with 10.8 +/- 2.9; P < 0.05). Furthermore, there was a positive correlation between the change in BP during HD and PWV in all subjects (r = 0.500; P < 0.001 for systolic blood pressure (SBP), a correlation that also existed for diastolic blood pressure (DBP) (P < 0.01). CONCLUSION: This study suggests that patients with HD-unresponsive BP are more likely to have vascular disease and this association between PWV and HD-induced BP changes might partly explain the apparent paradox of pre- and post-HD BP with mortality. It is proposed that a population with elevated post-HD BP is more likely to be composed of subjects with vascular disease (overt or occult), in contrast to a group with high pre-HD BP, which will be more heterogeneous.     

Ambulatory blood pressure monitoring and renal functions in children with a solitary kidney

The aim of this study is to investigate the blood pressure (BP) profile, microalbuminuria, renal functions, and relations with remaining normal kidney size in children with unilateral functioning solitary kidney (UFSK). Sixty-six children with UFSK were equally divided into three groups: unilateral renal agenesis (URA), unilateral atrophic kidney (UAK), and unilateral nephrectomy (UNP). Twenty-two age-, weight-, and height-matched healthy children were considered as a control group. The serum creatinine level and first-morning urine microalbumin and creatinine concentrations were determined by the standard methods. Also, the BP profile was determined by ambulatory blood pressure monitoring (ABPM). We found that the serum creatinine level was higher and creatinine clearance was lower in each patient groups compared to those of the control group (p < 0.05). Compared with the controls, each group of patients had mean office, 24-h, daytime, and night-time systolic and diastolic BP values similar to those of the controls (p > 0.05). An inverse correlation was found between the renal size standard deviation scores (SDS) of normal kidneys and 24-h systolic and diastolic BP load SDS in all of the patients (p < 0.05; r = −0.372, r = −0.295, respectively). The observed relationship between renal size SDS and 24-h mean arterial pressure (MAP), systolic and diastolic BP load SDS suggests that children with UFSK should be evaluated by using ABPM for the risk of hypertension.     

Relationship of ambulatory blood pressure monitoring data to echocardiographic findings in haemodialysis patients

BACKGROUND: The present study was performed to assess the value of ambulatoryblood pressure monitoring (ABPM) in determining the adequacyof blood pressure (BP) control, and its relationship to echocardiographicfindings in haemodialysis (HD) patients. METHODS: We studied 40 non-diabetic adult patients who had been on regularHD treatment for a median duration of 43 months. Twenty-four-hourABPM was performed using a non-invasive ABP monitor (Pressurescan,ERKA). Casual BP (cBP) was defined as the average of two measurementsobtained at two HD sessions, one preceding and one followingthe ABP recordings, and was calculated for both the predialysisand postdialysis phases. Two-dimensional and M-mode echocardiographywere performed in each patient to determine interventricularseptal thickness (IVS), left ventricular posterior wall thickness(LVPW), left ventricular fractional shortening (FS), and leftventricular mass index (LVMI) RESULTS: According to average 24-h BP levels, 50% of the patients hadsystolic hypertension (HT) (>139 mmHg), and 72.5% had diastolicHT (>87 mmHg), while only 25% had been diagnosed as HT bycBP measurements (P>0.01 and P>0.0001 respectively). Diurnalvariation in BP was not present in about 80% of the patients.Echocardiography was normal in only four patients (10%). LVMIand LV wall thickness were correlated to ABPM data better thanto cBP measurements. Using stepwise linear regression analysis,LVMI and FVS were positively correlated with systolic BP load(P> 0.0001 and P=0.0001 respectively), and LVPW was positivelycorrelated with night-time systolic BP level (P>0.001). CONCLUSIONS: ABPM is necessary to assess the adequacy of BP control, andis well correlated to end-organ damage of HT in HD patients.     

Blood pressure in the long-term follow-up of children with hemolytic uremic syndrome

The hemolytic uremic syndrome (HUS) is the most common cause of acute renal failure (ARF) in young children. Most patients recover from the acute phase of the illness but they may develop arterial hypertension (AH) after many years, even in the absence of signs of renal impairment during short-term follow-up. In this study, we performed casual blood pressure (BP) measurement, 24-h blood pressure monitoring (ABPM), and a Bruce walking treadmill study (ET) in 24 children (aged 5–15 years, 13 males, 11 females) with a history of HUS and normal renal function during follow-up (median 5.8 years, range 1.8–12.4 years). There were 22 children (91%) with prodromal diarrhea associated with HUS and 20 (83%) underwent dialysis during the acute illness. All children had normal casual BP measurement. Of 13 children (54%) with normal ABPM, 5 patients (38%) had an abnormal BP response during the ET study. There were 4 (58%) of the 7 patients with AH by ABPM (29%) and an abnormal BP response during ET. These findings suggest that ET could be a useful means of identifying children with a history of HUS that could be at risk of future AH even if they had normal renal function, casual BP, and ABPM during long-term follow-up. These results should be confirmed with a large prospective clinical study.     

Blood pressure and cardiovascular involvement in children with neurofibromatosis type1

We evaluated blood pressure in a sample of patients with neurofibromatosis type 1 (NF1), using ambulatory blood pressure monitoring (ABPM), to determine whether ABPM, when compared with casual BP recordings, allowed the detection of a higher risk for hypertension. We also evaluated the correlation between BP and vascular abnormalities. We studied 69 NF1 patients (36 males and 33 females) with a mean age of 11±4 years, divided into group A, with 24-h mean systolic blood pressure (SBP) or diastolic blood pressure (DBP) <95th percentile, and group B, with mean SBP or DBP >95th percentile. Standard electrocardiography and M-mode, two-dimensional echocardiography were performed and all patients were in sinus rhythm. ABPM identified 11 hypertensive patients (16%); 5 had a mean SBP >95th percentile, 3 mean SBP–DBP >95th percentile, and 3 a mean DBP >95th percentile. Laboratory and other investigations to exclude secondary hypertension were normal. Cardiac abnormalities were found in 13 of the 69 patients (18.8%) with NF1. There were no significant clinical and cardiac differences between the normotensive and hypertensive group. Our data emphasize the importance of periodic ABPM in NF1 patients to diagnose hypertension early and avoid target organ damage and increased mortality.     

Does diurnal variation in blood pressure exist in CAPD patients?

The existence of diurnal variation in CAPD remains controversial.We therefore attempted to delineate the blood-pressure (BP)pattern in CAPD patients by ambulatory blood-pressure monitoring(ABPM). Initially ABPM was performed in 31 patients (21 M, 10F), mean age 65.4 years (26–87) using the Spacelabs model90207. The maximal normal BP preset on the recorder was 140/90mmHg. Daytime and night-time readings, recorded every 30 min,were defined as those from 0600 to 2100 and 2100 to 0600 hoursrespectively. Mean duration of dialysis was 15.2 months (3–76). There were 14 hypertensive patients, defined as a basal BP >140/90 mmHg, or those on antihypertens-ive medications. Takingthe group as a whole a significant difference between day andnight-time readings was found as regards minimal systolic BP(118 versus 107.6 mmHg), maximal systolic BP (181.6 versus 171.2mmHg), mean diastolic BP (83.9 versus 79.6 mmHg), and maximaldiastolic BP (121.7 versus 104.5 mmHg), P<0.05. Diurnal variation,defined in the initial study as a 10% decrease of MAP occurringduring any consecutive 4-h period, was present in 21 patients.In three the diurnal variation manifested as a paradoxical reductionof BP during the day. The only significant difference betweenthose with diurnal variation and those without was the durationof dialysis, being 19.2 ±19.9 versus 13.3 ±17.3months respectively, (P<0.05). In a second study 18 hypertensive CAPD patients were subjectedto ABPM. Nine of them had participated in the first study. Thesepatients were specifically asked to detail their periods ofsleep and arousal. Diurnal variation was here defined as a 10%decrease of MAP occurring 2 h after the onset of sleep. Diurnalvariation was found to exist in 10 patients (55%). Comparingthe day to night-time readings in this group, no significantdifferences were found in mean systolic and MAP. When, however,the arousal versus sleep period readings were compared, a significantdifference was observed in mean diastolic BP (83±14 versus77±17mmHg, P<0.01), and in the MAP (104 ± 18versus 98±20.5 mmHg, P<0.01). The mean systolic BPjust failed to reach statistical significance (141±26versus 137±30 mmHg) due probably to the small samplesize. We conclude that diurnal variation exists in the majority ofCAPD patients. Our findings support the concept that the setpoint model of diurnal variation, in which the major determinantis activity or arousal is the operative one in these patients.Due to disordered sleep patterns in patients on CAPD, diurnalvariation might thus be better elicited when taking into accounta decrease of MAP occurring during any consecutive 4-h period.     

Twenty-four hour ambulatory blood pressure monitoring in general practice.

OBJECTIVES: To assess the role of ambulatory blood pressure (BP) monitoring in the diagnosis of hypertension in general practice. BACKGROUND: Hypertension is usually diagnosed by means of casual office BP readings. However, ambulatory BP monitoring has shown that a significant proportion of patients diagnosed as hypertensive do not in fact have hypertension. METHOD: Sixty-four Indian patients diagnosed as having mild to moderate hypertension by means of casual measurements were subjected to 24-hour ambulatory blood pressure monitoring (ABPM). A BP load of > 35% was classified as true hypertension and < 35% as 'white coat' hypertension. White coat hypertensives were compared with the true hypertensive group with regard to various demographic characteristics, as well as to correlate ABPM and casual BP readings. RESULTS: A 23.44% prevalence of white coat hypertension was found. In addition, the demographic profile of such patients showed a preponderance of non-obese females (73.33%), the majority of whom were on concomitant medication (60%). A poor correlation was found between the casual office BP readings and the 24-hour ambulatory BP readings in the white coat hypertensive group compared with the true hypertensive group. CONCLUSION: White coat hypertension is common in patients diagnosed as having mild to moderate hypertension by means of casual BP readings. There are no reliable clinical indicators to identify patients with white coat hypertension. ABPM has been shown to be a useful method for differentiating white coat hypertensive groups from true hypertensive groups.     

Blood pressure assessment in haemodialysis patients: Comparison between pre-dialysis blood pressure and ambulatory blood pressure measurement

Aim: Hypertension is common in haemodialysis (HD) patients. Determining the most appropriate method of blood pressure (BP) measurement, representative of target organ damage, is still an issue. BP variations between pre‐ and post‐HD treatment, or between on‐dialysis day and off‐dialysis day, are common. The aim of this study was to examine the possible differences between pre‐HD office BP (OBP) levels, inter‐HD (iHD) or HD day 24 h ambulatory BP measurement (ABPM) with 48 h ABPM, where the latter was considered the gold standard. Methods: 163 HD patients were studied. BP was monitored consecutively for 48 h with a Takeda TM2421 device, then sub‐analysed into two periods of 24 h: HD and iHD day. An average of 12 sessions pre‐HD OBP measurements was determined. Results: OBP significantly overestimates systolic (SBP) and diastolic BP (DBP) when compared with 48 h ABPM. SBP and DBP are significantly higher on iHD day than on HD day: 141.2 ± 20.8 versus 137.9 ± 20.9, and 77.1 ± 11.1 versus 76.1 ± 10.9 (P < 0.01). No differences of SBP night/day ratio were reported between 48 h ABPM and iHD 24 h ABPM or HD 24 h ABPM. The highest correlations were reported between 48 h SBP/DBP with iHD or HD 24 h ABPM (r² = 0.95, P < 0.001), while the lowest between 48 h SBP/DBP and OBP (r² = 0.40, P < 0.01, r² = 0.12, P < 0.01). The narrowest limits of agreement using the Bland and Altman test were reported between 48 h SBP or DBP and 24 h iHD or HD day ABPM. Considering 48 h ABPM, 80.5% of patients had BP higher than the norm, compared with 61.7% of patients in the case of OBP (χ² = 13.28, P < 0.001). The sensibility for detecting hypertension for iHD day 24 h ABPM was 98.4%, with specificity of 90%. The sensibility of 24 h HD day ABPM was 90.3%, with specificity 96.6%. In the case of OBP, sensibility and specificity were considerably lower, that is, 72.6% and 83.3% respectively. Conclusion: Significant differences are shown between OBP and 48 h ABPM in the recognition of a hypertensive state. OBP measurement has a lower sensibility and specificity than 24 h ABPM, which remains a valid alternative approach to 48 h ABPM in HD patients. Errors of OBP estimation should be taken into account, with possible negative impact on treatment strategies and epidemiology studies.