Reproducibility of ambulatory blood pressure monitoring in daily practice.

The reproducibility of ambulatory blood pressure monitoring (ABPM) was investigated in 45 untreated hypertensive patients in an out-patient clinic. Subjects with symptoms or diseases which could probably give rise to an increase in blood pressure (BP) variability were excluded. Patients underwent office BP (OBP) measurements and ABPM measurements with the Oxford Medilog device twice. The data were edited following previous set standards. Reproducibility of ABPM was good for the group: 24 h ABPM difference 0/2 mm Hg, standard deviation of the difference (SDD) 12/6 mm Hg for systolic BP and diastolic BP respectively. For OBP the difference between the two visits was 5/2 mm Hg with a SDD of 15/8 mm Hg. Intra-individual reproducibility was poor; almost half of the patients had a systolic difference of more than 10 mm Hg between both ABPM recordings. Reproduciblity of the day-night difference with a BP fall of at least 10% (dipper status) was moderate. About 60% of the subjects were dippers at one of the ABPM recordings but only 42% had a reproducible dip. Possible factors playing a role in the disappointing reproducibility of the ABPM recordings are the difference in daily activities between both recording days, decreased accuracy at higher BP, quality of sleep and the probable lower accuracy of the device during real ambulant conditions. In daily practice ABPM has no better reproducibility than OBP measurements, despite the larger number of measurements.     

Night-time blood pressure load is associated with higher left ventricular mass index in renal transplant recipients

The absence of nocturnal fall in blood pressure (BP) is named as nondipper status, which has been shown to be an additional risk factor for the development of left ventricular hypertrophy and cardiovascular events in several high-risk groups. The aim of this study was to determine the influences of the nondipper status and nocturnal blood pressure loads on left ventricular mass index (LVMI) in renal transplant recipients. A total of 35 nondiabetic renal transplant recipients were included into the study. A 24-h ambulatory blood pressure monitoring (ABPM) was performed for all recipients. The nondipper status was defined as either an increase in night-time mean arterial pressure (MAP) or a decrease of no more than 10% of daytime MAP. LVMI was measured by using two-dimensional guided M-mode echocardiography. The night-time systolic blood pressure (SBP) load was defined as the percentage of the time, during which SBP exceeded 125 mmHg during night time. The nondipping was common among renal transplant recipients, of whom 60% were nondipper in our study. LVMI was significantly higher in the nondipper group vs the dipper group (133 +/- 35 g/m(2) vs 109 +/- 26 g/m(2), P = 0.04). A fall in MAP at night time was 14.5 +/- 4.3% in the dipper group, while it was 1.4 +/- 6.1% in the nondipper group (P < 0.001). On stepwise multiple regression analysis, night-time SBP load and haemoglobin were independent predictors of LVMI (R(2) = 0.53). In conclusion, nondipping is common after renal transplantation. Night-time SBP load and low haemoglobin are closely related to the increase in LVMI in renal transplant recipients. ABPM may be a more useful tool in optimizing treatment strategies to reduce cardio-vascular events in renal transplant recipients.     

The reproducibility of dipping status: beyond the cutoff points

A limited reproducibility has been ascribed to 24-h ambulatory blood pressure monitoring, especially in relation to the dipper and nondipper phenomena. This study examined the reproducibility of 24-h ambulatory blood pressure monitoring in three recordings of pressure at intervals of 8-15 days in 101 study participants (73% treated hypertensive patients) residing in the city of Recife, Pernambuco, Brazil. SpaceLabs 90207 monitors were used, and the minimum number of valid measurements was 80. No significant differences were found between the mean systolic and diastolic pressures, between the second and third recordings when the normotensive and hypertensive patients were assessed jointly (P=0.44). Likewise, no significant differences were present when the normotensive patients were analyzed separately (P=0.96). In the hypertensive group, a significant difference existed between only the first and second ambulatory blood pressure readings (135.1 vs. 132.9 mmHg, respectively; P=0.0005). Regarding declines in pressure during sleep, no significant differences occurred when continuous percentage values were considered (P=0.27). The values obtained from 24-h ambulatory blood pressure monitoring are reproducible when tested at intervals of 8-15 days. Small differences, when significantly present, always involved the first ambulatory blood pressure monitoring. The reproducibility of the dipper and nondipper patterns is of greater complexity because it considers cutoff points rather than continuous ones to characterize these states.     

Ambulatory blood pressure monitoring in haemodialysis and continuous ambulatory peritoneal dialysis (CAPD) patients

The aim of this study was to compare the results of the 44-h ambulatory blood pressure monitoring (ABPM) data between haemodialysis (HDp) and CAPD patients and to investigate the relation of circadian rhythm in blood pressure (BP) with development of left ventricular hypertrophy. Twenty-two HDp (11 male, 11 female, mean age: 50 +/- 17 years) and 24 CAPDp (11 male, 13 female, mean age: 47 +/- 15 years) were included. Echocardiographic measurements and ABPM were performed in all study groups. ABPM of the first and second days were analysed separately and compared with CAPDp. Left ventricular hypertrophy was detected in 17 of the 22 HDp (77%) and 17 of the 24 CAPDp (71%). There was no significant differences between HD and CAPDp in respect to 44-h, daytime and night-time systolic and diastolic BP values. Although the course of BP in CAPDp was stable during the 44-h period, systolic and diastolic BP levels on the second day were significantly higher than those of on the first day in HDp (P < 0.001 for both). Daytime systolic and diastolic BP levels on the first day in HD group were recorded lower than those of the CAPD group. On the second day, night-time BP readings (both systolic and diastolic BP) were measured significantly higher in the HD group compared with the CAPD group. Twenty-one of the 24 (88%) CAPD patients were dippers, whereas only four of the 22 (18%) HDp were dippers (P < 0.001). Dipper patients had significantly lower left ventricular mass index (LVMI) than non-dipper patients (131 +/- 29 g/m(2) vs 153 +/- 40 g/m(2), P = 0.03). In 44-h ABPM, there were no differences in daytime and night-time systolic and diastolic blood pressures between HD and CAPD patients. Non-dipper patients had increased LVMI as compared with dipper patients. Abnormalities in circadian rhythm of the blood pressure might be one of the implicated factors for development of left ventricular hypertrophy.     

Ambulatory blood pressure monitoring in a nonacademic setting. Effects of age and sex.

Twenty-four-hour ambulatory blood pressure measurements (ABPM) are likely to eliminate the stress of visits and observer bias in office blood pressure (BP) recordings, allow consideration of the circadian variability in BP, and correlate well with target organ damage. To define the prevalence of "white coat" hypertension in a rural community to a nonacademic setting, and to assess age and sex related differences, we studied 131 patients who had more than two prior office diastolic BP measurements greater than 90 mm Hg and less than 115 mm Hg. Blood pressure was measured every 10 to 60 min for 24 h using the SpaceLabs 90207 device. Office BP readings were higher than ABPM in the group as a whole, in individual age groups, and in both sexes. The differences were more pronounced at night. Average differences between office and ambulatory BP ranged between 14.4 +/- 1.7/2.9 +/- 2.0 (ABPM at 10:00), and 33.8 +/- 2.3/22.8 +/- 1.5 mm Hg (systolic/diastolic +/- SE) (ABPM at 01:00). The nighttime drop in systolic BP was not apparent in subjects more than 65 years old. Women had a proportionately higher mean office BP than men (115.0 +/- 0.9 office v 110.2 +/- 1.3 mm Hg ABPM in women and 112.3 +/- 0.9 v 104.3 +/- 1.1 mm Hg in men) (P = .013), and the elderly did not display the relationship between ambulatory and office mean BP seen in younger subjects (r = 0.15, P = .30 v r = 0.36, P = .0004, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

Distribution of 24-h ambulatory blood pressure in children: normalized reference values and role of body dimensions

BACKGROUND: Twenty-four-hour ambulatory blood pressure monitoring (ABPM) is an essential tool in the diagnosis and therapeutic monitoring of arterial hypertension in children. The statistical use of pediatric ABPM reference values has been compromised by the non-Gaussian distribution of 24-h blood pressure (BP) in children. OBJECTIVE: To develop distribution-adjusted pediatric ABPM reference tables. METHODS: From cross-sectional ABPM data obtained in 949 healthy children and adolescents aged 5-20 years, a set of reference tables was developed for 24-h, daytime and night-time mean values of systolic, diastolic, mean arterial BP and heart rate, utilizing the LMS method to account for the variably skewed distribution of ABPM data. Age- and gender-specific estimates of the distribution median (M), coefficient of variation (S) and degree of skewness (L) were obtained by a maximum-likelihood curve-fitting technique. The estimates of, and can be used to normalize ABPM data to gender and age or height. RESULTS: Re-application of the established, and values in the reference population confirmed appropriate normalization of ABPM values. Height standard deviation scores (SDS), body mass index (BMI) SDS and heart rate SDS were independent positive predictors of 24-h systolic BP SDS. Diastolic 24-h mean BP SDS showed a weak correlation with BMI SDS only. CONCLUSIONS: The use of LMS reference tables permits calculation of appropriate SDS values for ABPM in children. Whereas systolic 24-h BP is independently correlated with age, relative height and obesity, diastolic values are almost independent of age and relative height, and weakly associated with relative obesity.     

Ambulatory blood pressure level rather than dipper/nondipper status predicts vascular events in type 2 diabetic subjects.

To clarify which parameter, diurnal pattern of blood pressure (BP) or level of BP variability, has the stronger predictive value for fatal and nonfatal vascular events, vital status after a mean (+/-SD) follow-up period of 86+/-46 months was determined in 392 type 2 diabetic subjects without any history of vascular disease, in whom the 24-h BP profile had been monitored between 1988 and 1998. After the exclusion of 28 subjects who died during the follow-up period of causes unrelated to diabetes, 364 subjects were recruited for further analysis. A total of 147 first events, including 50 fatal vascular events and 97 nonfatal vascular events, were recorded during the follow-up period. The rates of various vascular events increased with both reduced nocturnal falls in systolic BP (SBP) and levels of all ambulatory BP parameters. The ambulatory BP parameter showing the largest area under the receiver operating characteristic curve (ROCAUC) for fatal events was the mean 24-h pulse pressure (PP), and that for nonfatal events was the mean nighttime SBP; both exceeded the respective values of nocturnal fall in SBP. Furthermore, when dipper and nondipper diabetic subjects were divided into subgroups based on the 24-h PP (54.3 mmHg) and the nighttime SBP (116.5 mmHg) cut-off points derived from the ROC analyses, Kaplan-Meier plots showed that the diabetic subgroups with high ambulatory BP levels had worse outcomes, independent of dipper/nondipper status. Finally, these parameters were applied to the Cox model with the values of nocturnal fall in SBP and other confounding factors, and results showed that mean 24-h PP and mean nighttime SBP predicted fatal and nonfatal vascular events, respectively, more strongly than nocturnal fall in SBP in type 2 diabetic subjects. These findings therefore suggest that ambulatory BP levels in type 2 diabetic subjects have a higher predictive value for organ damage and death compared with diurnal BP patterns or dipper/nondipper status.     

Ambulatory vs Office Blood Pressure Monitoring in Renal Transplant Recipients

Hypertension is common following renal transplantation and has adverse effects on cardiovascular and graft health. Ambulatory blood pressure monitoring (ABPM) is better at overall blood pressure (BP) assessment and is necessary to diagnose nocturnal hypertension, which is also implicated in poor outcomes. The authors performed a retrospective analysis of 98 renal transplant recipients (RTRs) and compared office BP and ambulatory BP recordings. ABPM revealed discordance between office BP and ambulatory BP in 61% of patients, with 3% caused by white‐coat and 58% caused by masked hypertension (of which 33% were caused by isolated nocturnal hypertension). Overall, mean systolic BP was 3.6 mm Hg (0.5–6.5) and diastolic BP was 7.5 mm Hg (5.7–9.3) higher via ambulatory BP than office BP. This was independent of estimated glomerular filtration rate, proteinuria, transplant time/type, and comorbidities. A total of 42% of patients had their management changed after results from ABPM. ABPM should be routinely offered as part of hypertension management in RTRs.     

Aldosterone excess and resistance to 24-h blood pressure control

BACKGROUND: Aldosterone excess has been reported to be a common cause of resistant hypertension. To what degree this represents true treatment resistance is unknown. OBJECTIVE: The present study aimed to compare the 24-h ambulatory blood pressure monitoring (ABPM) levels in resistant hypertensive patients with or without hyperaldosteronism. METHODS: Two hundred and fifty-one patients with resistant hypertension were prospectively evaluated with an early-morning plasma renin activity (PRA), 24-h urinary aldosterone and sodium, and 24-h ABPM. Daytime, night-time, and 24-h blood pressure (BP) and nocturnal BP decline were determined. Hyperaldosteronism (H-Aldo) was defined as suppressed PRA (<1.0 ng/ml per h or <1.0 mug/l per h) and elevated 24-h urinary aldosterone excretion (>/= 12 mug/24-h or >/= 33.2 nmol/day) during ingestion of the patient's routine diet. RESULTS: In all patients, the mean office BP was 160.0 +/- 25.2/89.4 +/- 15.3 mmHg on an average of 4.2 medications. There was no difference in mean office BP between H-Aldo and normal aldosterone status (N-Aldo) patients. Daytime, night-time, and 24-h systolic and diastolic BP were significantly higher in H-Aldo compared to N-Aldo males. Daytime, night-time, and 24-h systolic BP were significantly higher in H-Aldo compared to N-Aldo females. Multivariate analysis indicated a significant interaction between age and aldosterone status such that the effects of aldosterone on ambulatory BP levels were more pronounced with increasing age. CONCLUSIONS: In spite of similar office BP, ABPM levels were higher in resistant hypertensive patients with H-Aldo. These results suggest that high aldosterone levels impart increased cardiovascular risk not reflected by office BP measurements.     

'Office-hour' ambulatory blood pressure monitoring is sufficient for blood pressure diagnosis

We conducted this study to determine whether 'office hour', defined as time period from 0800 to 1800 hours, ambulatory blood pressure monitoring (ABPM) predicts daytime ('waking-hour') and 24-h ABPM results, and to examine the impact of sleep disturbance on ABPM and nocturnal dip. Eighty-four patients (mean age 49+/-18 years, 47 males) were studied. Systolic, diastolic and mean 4-, 6-, 8-, 'office-hour' as well as 'waking-hour' blood pressures (BPs) were obtained from 24-h ABPM readings. Of these, no statistical differences were found between 8-h and 'office-hour' systolic, diastolic and mean BPs compared to 'waking-hour' values. There was complete concordance between 'office-hour' and 'waking-hour' ABPM diagnosis based on British Hypertension Society definitions. Sleep disturbance was found in 22 patients (26%). Although nocturnal dip was not significantly different in either sleep-disturbed or non-disturbed patients, patients who reported sleep disturbance had significantly higher proportion of borderline/abnormal BP diagnosis compared to non-sleep-disturbed counterpart during both 'waking hour' and night time. In patients without sleep disturbance, there was complete concordance between 'office-hour', 'waking-hour' and 24-h ABPM diagnosis based on British Hypertension Society definitions. 'Office-hour' ABPM is predictive of 'waking-hour' and 24-h ambulatory BP readings. Sleep disturbance is common in patients undergoing the test, and significantly raises the BP readings. We therefore propose 'office-hour' ABPM as an accurate, reliable and comfortable method of continual non-invasive BP monitoring, and omitting routine night time BP monitoring.     

Clinical trial of arotinolol in the treatment of hypertension: dippers vs. non-dippers.

To compare the effects of an alpha, beta blocker, arotinolol, in the treatment of essential hypertension between patients with a dipper and those with a non-dipper profile by means of 24-h ambulatory blood pressure monitoring (ABPM), a multicenter single blind parallel trial was carried out in five clinical centers. After a one-week single blind placebo run-in period, the patients underwent ABPM if their clinic diastolic blood pressure (DBP) ranged from 90-109 mmHg and their clinic systolic blood pressure (SBP) was <180 mmHg. They were divided into two groups according to the absence (non-dipper group, 24 cases) or presence (dipper group, 23 cases) of nocturnal BP reduction > or =10% of daytime BP. ABPM was measured again at the end of the active treatment phase. All patients were given Arotinolol 10-20 mg twice daily for 4 weeks. Twenty four-hour systolic and diastolic average BPs (MSBP, MDBP), 24-h systolic and diastolic blood pressure load (LS BP, LDBP), daytime systolic and diastolic average BPs (dMSBP, dMDBP), daytime systolic and diastolic blood pressure load (dLSBP, dLDBP), nighttime systolic and diastolic average BPs (nMSBP, nMDBP) and nighttime systolic and diastolic blood pressure load (nLSBP, nLDBP) were calculated. Arotinolol was effective in 78.2% of dippers and 54.2% of non-dippers, but the difference in effectiveness between these groups was not statistically significant. After treatment, SBP and DBP-including 24-h, daytime and nighttime systolic and diastolic BPs- were significantly reduced in both groups. During the daytime period, the systolic and diastolic blood pressures were significantly reduced in both dippers and non-dippers, while nighttime systolic and diastolic blood pressures were significantly reduced only in the non-dipper group. No significant changes were found in the dipper group over this period. In conclusion, Arotinolol, which can be dosed twice daily, is an effective antihypertensive agent which effectively lowers blood pressure during the day while reducing nighttime blood pressure more in non-dippers than in dippers, without excessive lowering blood pressure in the latter.     

A pressure-time index' for assessing the severity of essential hypertension.

OBJECTIVE: A new derivative of 24 h ambulatory blood pressure monitoring (ABPM) is introduced and its association with left ventricular mass index (LVMI) in essential hypertension is examined. PATIENT: population One hundred and fifty-three previously untreated essential hypertension patients. METHODS: Patients underwent casual blood pressure (BP) readings, 24 h ABPM and left ventricular echocardiographic assessment The following 24 h awake and sleep ABP variables were calculated: mean systolic and diastolic BP, systolic and diastolic BP loads (percentage of systolic readings > 140/120 mmHg (day/ night) and diastolic readings > 90/80 mmHg (day/night)), standard deviation of systolic and diastolic ABP and nocturnal fall of systolic BP, as well as the integrated areas under the ABP curve. The area under the BP curve divided in horizontal slices was accurately modelled by a sigmoid curve. The parameters controlling the shape of the curve and in particular that regarding its 'slope' is hereafter called the 'pressure-time index'. RESULTS: 'Systolic pressure-time index 24 h' (SPTI24) is related to left ventricular mass index (multivariate analysis, P= 0.008). Using either partial correlation coefficients or a multivariate analysis, SPTI24 is related to left ventricular mass index, independently of age, casual blood pressure, mean systolic and diastolic ABP, systolic and diastolic BP loads, BP variability (standard deviation (SD), nocturnal fall of systolic BP) and integrated area under the curve (multivariate analysis, P= 0.004). CONCLUSIONS: In essential hypertension, the SPTI24 is related to LVMI independently of age, casual blood pressure, integrated area under the curve or any other derivative of 24 h ABPM, and might be used to assess the extent of hypertensive load.     

Rosiglitazone reduces office and diastolic ambulatory blood pressure following 1-year treatment in non-diabetic subjects with insulin resistance

OBJECTIVE: Rosiglitazone (RSG) has been reported to reduce blood pressure (BP) in patients with type-2 diabetes, but similar effects in non-diabetic people with insulin resistance is less clear. Our aim was to test the long-term BP-lowering effects of RSG compared with placebo. METHODS: We recruited participants for BP evaluation of RSG treatment from a larger intervention trial. Office BP was recorded in 355 non-diabetic subjects with insulin resistance randomized to receive either RSG or placebo for 52 weeks. Ambulatory BP monitoring (ABPM; Spacelab 90207) was performed in a subgroup of 24 subjects (RSG: n = 11; placebo n = 13). RESULTS: After 1 year, the office BP decreased by -3.1 mmHg systolic (p<0.05) and -3.8 mmHg diastolic (p<0.001) in the RSG group versus placebo. In patients treated with RSG, at 1 year there was a trend for a reduction from baseline for mean 24-h diastolic BP (DBP), daytime DBP and night-time DBP (-4.39, -5.26 and -2.93 mmHg, respectively). However, only daytime DBP was significantly lower in the RSG group compared with control (adjusted mean difference: -4.41 mmHg, p = 0.007). There was also a non-significant trend for a reduction in mean 24-h systolic BP (SBP), daytime SBP and night-time SBP (-2.70, -2.51 and -3.35 mmHg, respectively). CONCLUSIONS: RSG treatment for 1 year was associated with a small but significant decrease in diastolic 24-h ambulatory diastolic BP, and both systolic and diastolic office BPs in non-diabetic people with insulin resistance.     

Reproducibility of the circadian blood pressure pattern in 24-h versus 48-h recordings: the Spanish Ambulatory Blood Pressure Monitoring Registry

OBJECTIVES: To assess the reproducibility of the circadian blood pressure (BP) pattern over a 48-h period by comparing the first 24 h of ambulatory blood pressure monitoring (ABPM) with the following 24 h and with the mean over 48 h. PATIENTS AND METHODS: Patients undergoing 48-h ABPM within the National ABPM Registry of the Spanish Society of Hypertension, based on 800 Spacelabs 90207 monitors distributed throughout Spain in hypertension units and primary healthcare centres, were included. Between June 2004 and September 2005, 611 valid 48-h ABPM recordings were obtained, 235 corresponded to patients without antihypertensive treatment. RESULTS: The percentages of patients classified as non-dipper for the first 24 h, the second 24 h and the 48-h average were 47, 50 and 48%, respectively. When the first and second 24-h periods were compared, 147 (24%) subjects switched from dipper (D) to non-dipper (ND) or vice-versa. When the first 24-h period was compared to the 48-h average, 66 (11%) subjects switched patterns. The proportions were similar separately for systolic blood pressure (SBP) and diastolic blood pressure (DBP) and between treated and untreated patients. In subjects with poor ABPM reproducibility, night-to-day ratios were of an intermediate value between those of subjects always classified as D or ND. CONCLUSION: Categorization of D or ND based on a single 24-h ABPM is moderately reproducible, since one out of every five patients change profile over the following 24 h. Nevertheless, the use of 48-h ABPM in clinical practice should be assessed according to cost-effectiveness criteria. Night-to-day ratios may be helpful in identifying patients with a stable profile.     

Blood pressure measurements,blood pressure variability and endothelial function in renal transplant recipients

Background/Aims: Hypertension is an important cardiovascular risk factor in renal transplant recipients. Elevated blood pressure variability (BPV) during 24-h ambulatory blood pressure monitoring (ABPM) is associated with increased risk of target organ damage and cardiovascular events, independent of mean blood pressure levels. We aimed to evaluate the relationship between endothelial function, blood pressure levels obtained by various measurement methods, and BPV in renal transplant recipients.

Methods: In total, 73 hypertensive renal transplant recipients were included in the study. Office blood pressure measurements, central blood pressure measurements, home blood pressure measurements and 24-h ABPM were obtained from the subjects. BPV was calculated using the average real variability index. All patients underwent brachial flow-mediated vasodilatation tests. Predictive values of blood pressures obtained by different measurement techniques and BPV on endothelial functions were investigated.

Results: Endothelial dysfunction was present in 68.5% of the patients. No difference was found between the group with and without endothelial dysfunction with regard to office systolic or diastolic blood pressure, central blood pressure or home systolic blood pressure. In the group with endothelial dysfunction, 24-h ambulatory systolic blood pressure and night-time ambulatory systolic blood pressure were higher. In patients with endothelial dysfunction, the 24-h systolic, diastolic and mean BPV were all higher. There was also a negative correlation between the percentage of flow-mediated vasodilatation with 24-h mean and systolic BPV.

Conclusion: Patients with endothelial dysfunction had significantly higher ambulatory blood pressure values and higher BPV. There was a significant negative correlation between endothelial function and BPV.     

Comparing office-based and ambulatory blood pressure monitoring in clinical trials

Ambulatory blood pressure monitoring (ABPM) is commonly used in clinical trials. Yet, its ability to detect blood pressure (BP) change in comparison to multiple office-based measurements has received limited attention. We recorded ambulatory and five daily pairs of random zero (RZ) BPs pre- and post-intervention on 321 adult participants in the multicentre Dietary Approaches to Stop Hypertension trial. Treatment effect estimates measured by ambulatory monitoring were similar to those measured by RZ and did not differ significantly for waking vs 24-h ambulatory measurements. For systolic BP, the standard deviations of change in mean 24-h ambulatory BP (8.0 mmHg among hypertensives and 6.0 mmHg among nonhypertensives) were comparable to or lower than the corresponding standard deviations of change in RZ-BP based on five daily readings (8.9 and 5.9 mmHg). The standard deviations of change for mean waking ambulatory BP (8.7 and 6.7 mmHg) were comparable to those obtained using three to four daily RZ readings. Results for diastolic BP were qualitatively similar. Ambulatory monitoring was more efficient (ie, a smaller sample size could detect a given BP change) than three to four sets of daily RZ readings and required fewer clinic visits. The average of 33 ambulatory BP readings during the waking hours had an efficiency comparable to that from the mean of four daily pairs of RZ-BPs. Participants readily accepted the ABPM devices, and their use requires less staff training. ABPM provides a useful alternative to RZ-BP measurements in clinical trials.     

Dynamic blood pressure changes and recovery under different work shifts in young women

BACKGROUND: Some studies have reported that shift work can affect blood pressure (BP), but few have studied recovery from BP changes occurring during different shifts. METHODS: We recruited 16 young female nurses working rotating shifts and six working the regular day shift. All received repeated ambulatory BP monitoring (ABPM) during their workdays and following day off. RESULTS: Our linear mixed-effect model showed that both systolic and diastolic BPs were significantly decreased during sleeping period and significantly increased while on working period, on a work day, but increased during sleeping period after a night shift or evening shift. BP measurements that changed after evening shift usually returned to baseline on consecutive off-duty day after day shift, but they did not completely return to baseline after a night shift (P < 0.05). We also found 69% of those working rotating shifts had at least changed once in dipper/nondipper status. The rates of change in dipper/nondipper status between work day and off-duty day were 33, 44, 50, and 38% for nurses worked in outpatient clinic, night shift, evening shift, and day shift, respectively. CONCLUSION: Shift work is significantly associated with BP and possibly dipper/nondipper status in young female nurses. Except for those working night shifts, BP levels returned to baseline the off-duty day after day shift. We recommend that potential influence of shift work be considered when evaluating a person's BP.     

Evaluation of the performance of a wrist blood pressure measuring device with a position sensor compared to ambulatory 24-hour blood pressure measurements

This randomized, single-center, open, within-subject study evaluated the performance of the Braun PrecisionSensor 2000 blood pressure (BP) measurement wrist device (BP 2000, Braun GmbH, Germany) with and without the position sensor, and compared the results with data obtained from 24-h ambulatory BP measurement (ABPM, A&D TM 2430). In a crossover design, 43 subjects performed BP measurements with the BP 2000 during two 7-day periods, one with the position sensor and the other without the position sensor. The correlation coefficients between all wrist self-measurements and ABPM were 0.73 for systolic and 0.65 for diastolic BP (with position sensor) compared to 0.70 and 0.60 for readings without position sensor, respectively. The categorization of subjects as normotensive or hypertensive, using the wrist device in subjects without specific training, achieved a correct classification of 84% (with position sensor) and 81% (without position sensor) in comparison to ABPM. When the measurements were performed in the clinic by an experienced observer, the correct classification was 79% in comparison to ABPM. The crossover study design did not show any significant variation between the two devices with regard to reproducibility of readings at the wrist. In conclusion, self-BP measurements with BP 2000, by untrained subjects, produced results consistent with those found recently with self-BP measurements with upper arm devices, when both data sets are compared with ABPM. The rates of false classification of normotension/hypertension with the wrist device were small and at least as reliable as office measurements.     

Reproducibility study of nocturnal blood pressure dipping in patients with high cardiovascular risk

It has been shown that in most people there is a physiological reduction in blood pressure during nighttime sleep, it falling by approximately 10% compared to daytime values (dippers). On the other hand, in some people, there is no nighttime reduction (non‐dippers). Various studies have found an association between being a non‐dipper and a higher risk of cardiovascular disease, but few have assessed whether the nocturnal pattern is maintained over time. From the database of the TAHPS study, data were available on 225 patients, each of whom underwent 24‐hour ambulatory blood pressure monitoring (ABPM) on four occasions over a period of 5 months. We studied the reproducibility of the nocturnal BP dipping pattern with mixed linear analysis and also calculated the concordance in the classification of patients as dippers or non‐dippers. The intraclass correlation coefficients between the different ABPM recordings were 0.482 and 0.467 for systolic and diastolic blood pressure, respectively. Two‐thirds (67%) and 70% of the patients classified, respectively, as dippers or non‐dippers based on systolic and diastolic blood pressure readings in the first ABPM recording were found to have the same classification based on the subsequent recordings. We conclude that the reproducibility of nocturnal dipping patterns and concordance of dipper vs non‐dipper status in individual patients is modest and therefore that we should be cautious about recommending treatments or interventions based on these patterns.     

New algorithm for the diagnosis of hypertension

Most national and international guidelines for diagnosing hypertension include 24-h ambulatory blood pressure monitoring (ABPM) and self (home) BP monitoring (SBPM) as optional methods for identifying hypertensive patients. However, none of the current guidelines have yet included ABPM or SBPM as fundamental tools for diagnosing hypertension, preferring instead to rely on conventional office readings recorded by mercury sphygmomanometry. During the past 10 years, clinical outcome studies have consistently reported 24-h ABPM and SBPM to be significantly better predictors of cardiovascular events compared with the office BP, even when recorded under "research conditions." Based on the available evidence, the Canadian Hypertension Education Program has now developed an algorithm for diagnosing hypertension that offers three options: 1) conventional office BP, 2) SBPM, or 3) 24-h ABPM. Out-of-office BP measurements are recommended, whenever feasible, to minimize both measurement error associated with mercury sphygmomanometry and the white coat effect experienced by some patients.