Single Ambulatory Blood Pressure Monitoring Research Articles

Reproducibility of sequential ambulatory blood pressure and pulse wave velocity measurements in normotensive and hypertensive individuals.

Errors in blood pressure (BP) measurement account for a large proportion of misclassified hypertension diagnoses. Ambulatory blood pressure monitoring (ABPM) is often considered to be the gold standard for measurement of BP, but uncertainty remains regarding the degree of measurement error. The aim of this study was to determine reproducibility of sequential ABPM in a population of normotensive and well controlled hypertensive individuals. Individual participant data from three randomized controlled trials, which had recorded ABPM and carotid-femoral pulse wave velocity (PWV) at least twice were combined ( n = 501). We calculated within-individual variability of daytime and night-time BP and compared the variability between normotensive ( n = 324) and hypertensive ( n = 177) individuals. As a secondary analysis, variability of PWV measurements was also calculated, and multivariable linear regression was used to assess characteristics associated with blood pressure variability (BPV). Within-individual coefficient of variation (CoV) for systolic BP was 5.4% (day) and 7.0% (night). Equivalent values for diastolic BP were 6.1% and 8.4%, respectively. No statistically significant difference in CoV was demonstrated between measurements for normotensive and hypertensive individuals. Within-individual CoV for PWV exceeded that of BP measurements (10.7%). BPV was associated with mean pressures, and BMI for night-time measurements. PWV was not independently associated with BPV. The variability of single ABPM measurements will still yield considerable uncertainty regarding true average pressures, potentially resulting in misclassification of hypertensive status and incorrect treatment regimes. Repeated ABPM may be necessary to refine antihypertensive therapy.

Identifying patterns of diurnal blood pressure variation among ELSA-Brasil participants.

Ambulatory blood pressure monitoring (ABPM) is the gold standard method for the diagnosis of hypertension. ABPM provides a set of repeated measurements for blood pressure (BP), usually over 24h. Traditional approaches characterize diurnal BP variation by single ABPM parameters such as average and standard deviation, regardless of the temporal nature of the data. In this way, information about the pattern of diurnal BP variation and relationship between parameters is lost. The objective of this study was to identify and characterize daily BP patterns considering the set of repeated measures from 24-h ABPM. A total of 859 adult participants of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) performed a 24-h ABPM record. Hypertension, sex, age, race/color, education, marital status, smoking, alcohol, physical activity, and BMI were the covariables analyzed. Techniques for longitudinal clustering, multinomial models, and models with mixed effects were used. Three daily BP patterns were identified. Daily BP patterns with high BP presented higher standard deviation and morning surge and lower nocturnal dipping. They showed greater systolic BP variability and faster rise than fall in diastolic BP during sleep. Hypertensive, "pardos," and men had greater odds to present these patterns. Daily BP patterns with high BP presented the worst profile concerning ABPM parameters associated with cardiovascular risk. The daily BP patterns identified contribute to the characterization of diurnal BP variation.

Limited reproducibility of 24-h ambulatory blood pressure monitoring

Results of 24-h ambulatory blood pressure monitoring (ABPM) including average blood pressure, variability, and nocturnal dipping are considered the gold standard for diagnosis and the best predictor of the future end organ damage in chronic hypertension. Here we report on the reproducibility of ABPM results for these three measures over a period of months. A total of 35 hypertensive patients (43% female, mean age 64 years), underwent two separate ABPM recordings within 14 weeks, with unchanged medical treatment and lifestyle in the interim. The day and night average blood pressure, dipping status of systolic pressure, and the standard deviation of systolic and diastolic blood pressure as a measure of variability were compared between the two recordings. Individual values for average systolic and diastolic pressures showed only a modest correlation between the two measurements (r = 0.56, r = 0.81, p < 0.01). Standard deviations of 24-h pressure were also positively but weakly correlated (r = 0.4, p < 0.001). The occurrence of dipping was reproducible in 71% of the patients. Average blood pressure, pressure variability, and dipping as assessed by ABPM are only moderately reproducible. Clinical decision-making based on single ABPM datasets should be made with caution, and repetition of ABPM seems justified in some cases.

Reproducibility of ambulatory blood pressure in treated and untreated hypertensive patients

We tested the reproducibility of ambulatory blood pressure (ABP), BP variability, and BP reduction in hypertensive patients. Forty-two hypertensive patients were enrolled, and ABP monitoring (ABPM) was performed four times in each patient: twice before and twice after the treatment. Morning BP was defined as the average of 2 h after waking, and morning BP surge (MBPS) was defined by four ways: sleep-trough, preawake, morning-evening and morning-after-bed surge. The BP variability was evaluated by standard deviation, weighted standard deviation, coefficient of variation and average real variability. The reproducibility was compared using the repeatability coefficient and the Bland-Altman's method. The awake, sleep, 24-h and morning BP were well corresponded in the first and the second ABPM values in each period. The four measures of BP variability also corresponded well between the first and the second ABPM values in each period. MBPS did not correspond well in each period when it was defined by diaries, but the extent of correlation was improved when it was defined by actigraphy. The reproducibility of BP-lowering effect was fair when it was defined by a single parameter, but not very good when it was defined by two parameters (e.g. MBPS). The reproducibility of ABP levels and BP variability was fairly good and that of MBPS was moderate when defined by actigraphy. The good reproducibility of BP reduction means that each single ABPM, before and after the treatment, is acceptable for the assessment of drug efficacy.

Reliability of Blood Pressure Patterns Defined by a Single 24-Hour Ambulatory Blood Pressure Monitoring: The Case of the Dipping/Non Dipping and Isolated Clinic Hypertension

Classification of hypertensive subjects according to different blood pressure patterns : i.e sustained vs isolated clinic hypertension (ICH) , dipping vs non dipping is now regarded as a useful mean for a more precise individual risk stratification and therapeutic making decisions. However, this subdivision is routinely based on a single ambulatory blood pressure monitoring (ABPM), despite the well-known day-to-day variability in blood pressure due to variations in mental, physical and environmental stimuli. In this short review we have tried to answer the following question : how reliable is the classification of non-dipping and ICH pattern based on single 24-h ABPM recording? Data from the recent literature clearly indicate that these categorizations in non diabetic mild to moderate hypertensive patients on the basis of a single ABPM are highly unreliable , as a large fraction of subjects (20-50%) classified in these categories at the first ABPM, do not confirm the same BP pattern during a second ABPM. Thus, these findings support the idea that a more reliable classification of patients according to dipping/nondipping status or ICH vs sustained hypertension should be performed by repeating a second ABPM within a short-term period.

How reliable is isolated clinical hypertension defined by a single 24-h ambulatory blood pressure monitoring?

Isolated clinical hypertension (ICH) is characterized by a persistently elevated clinic blood pressure in the presence of a normal day-time or 24-h ambulatory blood pressure (ABP). This definition is based on a single ABP monitoring (ABPM) and little attention has been focused on the reproducibility of this condition. To investigate the reliability of the criteria currently recommended by major hypertension guidelines to detect ICH based on a single 24-h ABPM session. A total of 611 never-treated grade 1 and 2 hypertensive patients (mean age 46 +/- 12 years) referred for the first time to our out-patient clinic, underwent repeated clinic blood pressure measurements, routine investigations, two 24-h periods of ABPM 1-4 weeks apart, cardiac and carotid ultrasound examinations. ABPM was always performed over a working day and the same daily activities were recommended during the two periods. ICH was diagnosed by the following criteria: (i) mean daytime values < 135/85 mmHg or (ii) mean 24-h blood pressure values < 125/80 mmHg during the first ABPM. The overall prevalence of ICH was 7.1% according to criterion (i) and 5.4% according to criterion (ii). Twenty (46.6%) of the 43 patients with mean daytime blood pressure values < 135/85 mmHg during the first ABPM, exceeded this cut-off value during the second ABPM period. Twenty-two (66.6%) of the 33 patients with mean 24-h blood pressure values < 120/80 mmHg during the first ABPM did not confirm a normal blood pressure profile during the second ABPM recording. Cardiovascular involvement was significantly lower in subjects with persistent normal ABP compared to those with non-reproducible ICH pattern or sustained hypertensives. These findings clearly indicate that: (i) the classification of ICH on the basis of a single ABPM, using the cut-offs suggested by major hypertension guidelines, has a limited short-term reproducibility and (ii) repeated ABPM recordings should be recommended to correctly diagnose patients with ICH and improve cardiovascular risk stratification.

Long-Term Reproducibility of Routine Ambulatory Blood Pressure Monitoring in Stable Pediatric Renal Transplant Recipients

The aim of this study was to evaluate, in stable pediatric renal transplant recipients, the long-term reproducibility of average office and ambulatory blood pressure (BP) readings and day-to-night BP variability under similar clinical conditions. The study involved 18 pediatric kidney transplant recipients who had repeated routine office and 24-h ambulatory BP monitoring (ABPM) in three visits, 12 months apart, over a 2-year period. Reproducibility of office and ambulatory BP averages between pairwise measurements were analyzed by calculating the mean difference and the standard deviation of the difference (SDD). Nondippers were arbitrarily defined by applying both a pediatric and an adult definition, respectively. Throughout the 2-year period, there were no significant differences in mean office, 24-h, daytime, night-time systolic, and diastolic BP values. Overall, SDD were lower for ambulatory BP recordings than for office BP measurements indicating a better long-term reproducibility for ABPM compared with office BP readings. The SDD for systolic and diastolic BP ranged from 12.4 to 13.7 and 6.3 to 9.5 for office BP and from 6.2 to 7.3 and 5.1 to 5.6 for 24-h BP, respectively. Regardless of the definition applied to define dipper and nondipper status, only half of the study group showed consistency in their circadian BP variability when comparing the three ABPMs. The present study demonstrates that long-term reproducibility of ABPM is superior to that for office measurements. Day-to-night BP variability, however, appears to change over time, making it questionable to classify a recipient as a dipper or nondipper during a single ABPM recording.

Reproducibility of nocturnal blood pressure fall in early phases of untreated essential hypertension: a prospective observational study.

A number of studies have shown that a smaller than normal nocturnal blood pressure (BP) decrease is associated with cardiovascular disease. However, no large prospective studies have examined the reliability of nocturnal dipping within individuals. The aim of our study was to investigate the short-term variability of nocturnal BP fall in a large cohort of patients with recently diagnosed essential hypertension. In all, 414 uncomplicated never treated hypertensive patients referred to our outpatient hypertension hospital clinic (mean age 46+/-12 years; 257 M, 157 F) prospectively underwent: (1). repeated clinic BP measurements; (2). routine examinations recommended by WHO/ISH guidelines; and (3). ambulatory BP monitoring (ABPM) twice within a 4-week period. Dipping pattern was defined as a reduction in the average systolic and diastolic BP at night greater than 10% compared to average daytime values. Overall, 311 patients (75.1%) showed no change in their diurnal variations in BP. Of the 278 patients who had a dipping pattern on the first ABPM, 219 (78.7%) confirmed this type of profile on the second ABPM, while 59 (21.3%) showed a nondipping pattern. Among 37 dipper patients with >20% of nocturnal systolic BP decrease (extreme dippers), only 16 (43.2%) had this marked fall in BP on the second ABPM. Of the 136 patients who had a nondipping pattern on the first ABPM, 92 (67.6%) confirmed their initial profile on the second ABPM, while 44 (32.4%) did not. Patients with reproducible nondipping profile were older (48+/-12 years) than those with reproducible dipping profile (44+/-12 years, P<0.05). These findings indicate that: (1). short-term reproducibility of nocturnal fall in BP in untreated middle-aged hypertensives is rather limited: overall, one-fourth of patients changed their initial dipping patterns when they were studied again after a few weeks; (2). this was particularly true for extreme dipping and nondipping patterns; (3). abnormalities in nocturnal BP fall, assessed by a single ABPM, cannot be taken as independent predictors of increased cardiovascular risk.

Short-term Reproducibility of Nocturnal Non-dipping Pattern in Recently Diagnosed Essential Hypertensives

Objective : To investigate in a selected population of patients with a recently diagnosed essential hypertension the short-term intrasubject variability of diurnal changes in blood pressure (BP). Methods : Two hundred and eight consecutive, recently diagnosed, never treated essential hypertensives (119 men, 89 women, 46 - 12 years) underwent 24-h ambulatory BP monitoring (ABPM) twice within 3 weeks. Dipping pattern was defined as a reduction in average systolic and diastolic BP at night greater than 10% compared to average daytime values. Results : 177 subjects (85%) showed no change in their diurnal variations in BP. Of the 159 subjects who had a dipping pattern on first ABPM, 134 (90.6%) confirmed this type of profile on the second ABPM, while 15 (9.4%) showed a non-dipping pattern. Of the 59 subjects who had a non-dipping pattern on the first ABPM, 43 (72.2%) confirmed their initial profile on the second ABPM, while 16 (28.8%) did not. Conclusion : These findings indicate that short-term reproducibility of diurnal changes in BP in early phases of untreated essential hypertension, characterized by a large prevalence of dipping pattern, is overall satisfactory. However, our study underlines that also in this particularly selected population of hypertensives the definition of non-dipping status on the basis of a single ABPM remains unreliable in about one-third of patients.