Ambulatory blood pressure monitoring: a critical review of the current methods to handle outliers

Berardi, Laurence; Chau, Nguyen Phong; Chanudet, X.; Vilar, José; Larroque, P

doi:10.1097/00004872-199210000-00019

Cited by 39 publications

(18 citation statements)

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“…18 The reported times of diner and lunch, awakening, and bedtime were used to compute mean SBP and DBP across all readings in the morning, afternoon, and evening. To assess the confounding of different physical activity patterns on ABP levels, we also computed the average ABP on the 3 periods of the day using only BP values obtained during sitting activities.…”

Section: Data Reductionmentioning

confidence: 99%

Heritability of Daytime Ambulatory Blood Pressure in an Extended Twin Design

et al. 2005

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Abstract-The present study estimated the genetic influences on ambulatory systolic and diastolic blood pressure, and on hypertensive status derived from ambulatory levels, in a family sample of 535 twins and 257 singleton siblings. This "extended twin design" was used to explicitly test the possibility that results obtained in singleton siblings are different from those obtained in twins. To examine the effects of excluding (medicated) hypertensive subjects, the genetic analyses were first performed under strict exclusion (medication and/or blood pressure Ͼ135/85 mm Hg), then without the medicated subjects, and, finally, without any exclusion. For the latter analysis, the untreated blood pressure values in subjects using antihypertensive medication were estimated by augmenting the observed blood pressure by the published efficacy of the specific antihypertensive medication used. No evidence was found for differential means, variances, or covariances of ambulatory blood pressure in singletons compared with twins. This indicates that estimates of heritability of ambulatory blood pressure from twin studies can be generalized to the singleton population. Heritability of hypertension, defined as a mean daytime blood pressure Ͼ135/85 mm Hg or antihypertensive medication use, was 61%. Genetic contribution to ambulatory blood pressure was highest when all subjects were included (systolic, 44% to 57%; diastolic, 46% to 63%) and lowest under strict exclusion (systolic, 32% to 50%; diastolic, 31% to 55%). We conclude that exclusion of (medicated) Most of these studies have based their genetic analyses on conventional office BP measurements. The genetics of ambulatory BP (ABP) may differ, however, because it is unaffected by the "white-coat" effect. 6 The added value of ABP measurements is best illustrated by studies showing that ABP is a better predictor of target organ damage, 7 cardiovascular morbidity, and mortality 8,9 than conventional office BP.To date, only 4 twin studies 10 -13 and 1 family study 14 reported heritability estimates for daytime or 24-hour ABP. Estimates ranged from 22% to 62% for systolic blood pressure (SBP) and from 38% to 63% for diastolic blood pressure (DBP). With the exception of studies by Vinck et al 12 and Fagard et al,13 sample sizes for the twin analyses have been rather small, ie, at most, 66 pairs in total. Thus, there is a relative paucity of adequately powered twin studies on ambulatory measures. One way of increasing statistical power is to include singleton siblings. Such an extended twin design 15 further provides an optimal design to address the question whether results from twin studies on the genetics of ABP may be generalized to the singleton population, because it matches twins and singletons for familial factors like socioeconomic status (SES), diet habits, and maternal behaviors during pregnancy.Existing twin and family studies of ABP have excluded subjects using antihypertensive medication, 12,13 or have been performed with analyses of normotensive subjects only, 10,11 ther...

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Section: Data Reductionmentioning

confidence: 99%

Heritability of Daytime Ambulatory Blood Pressure in an Extended Twin Design

et al. 2005

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“…The recommendations for excluding artefactual readings and outliers from ambulatory blood pressure records summarized by [22] were followed. All systolic blood pressure values of , 70 or .…”

Section: Data Reduction and Analysismentioning

confidence: 99%

Ambulatory heart rate is underestimated when measured by an ambulatory blood pressure device

Vrijkotte

Geus

2001

Journal of Hypertension

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Objective To test the validity of ambulatory heart rate (HR) assessment with a cuff ambulatory blood pressure (ABP) monitor.Design Cross-instrument comparison of HR measured intermittently by a cuff ABP monitor (SpaceLabs, Redmond, Washington, USA), with HR derived from continuous electrocardiogram (ECG) recordings (1) in a controlled laboratory experiment and (2) during long-term recording in a true naturalistic setting.Participants Six normotensive subjects participated in the laboratory study. A total of 109 male white-collar workers underwent ambulatory monitoring, of which 30 were mildly hypertensive.Methods Four different laboratory conditions (postures: lying, sitting, standing, walking), repeated twice, were used to assess the short-term effects of cuff in¯ation on the HR. To test the actual ambulatory validity, participants simultaneously wore a continuous HR recorder and the ABP monitor from early morning to late evening on 2 workdays and one non-workday. Diary and vertical accelerometery information was used to obtain periods of ®xed posture and (physical) activity across which HR from both devices was compared.Results. Laboratory results showed that the ABP device reliably detected HR during blood pressure measurement, but that this HR was systematically lower than the HR directly before and after the blood pressure measurement. The ambulatory study con®rmed this systematic underestimation of the ongoing HR, but additionally showed that its amount increased when subjects went from sitting to standing to light physical activity (2.9; 4.3 and 9.1 bpm (beats/min), respectively). In spite of this activity-dependent underestimation of HR, the correlation of continuous ECG and intermittent ABP-derived HR was high (median r 0.81). Also, underestimation was not different for normotensives and mild hypertensives.Conclusions A direct effect of cuff in¯ation leads to the underestimation of ongoing HR during cuff-based ABP measurement. Additional underestimation of HR occurs during periods with physical activity, probably due to behavioural freezing during blood pressure measurements. HR underestimation was not affected by hypertensive state. When its limitations are taken into account, ABP-derived ambulatory HR can be considered a reliable and valid measure.

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“…In the evening, monitors were removed and returned to the investigators on the following day, when data were down-loaded for analysis. Blood pressure and heart rate readings were subsequently reviewed and outliers were excluded according to the methods described by Berardi et al 48 …”

Section: Ambulatory Monitoringmentioning

confidence: 99%

The influence of abdominal obesity and chronic work stress on ambulatory blood pressure in men and women

et al. 1999

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OBJECTIVE: To assess the in¯uence of abdominal obesity and work stress (operationalised as low control over work) on ambulatory blood pressure on a working day and evening. PARTICIPANTS AND METHODS: 156 school teachers (58 men and 98 women) carried out ambulatory blood pressure and heart rate monitoring on a work day and evening. Cardiovascular activity was also measured under baseline conditions on another occasion, when body weight, height, waist and hip circumference were assessed. Perceived control over work was assessed by questionnaire, along with mental health, anger expression and social support. 126 participants repeated the protocol after 12 months. Waistahip ratio was used as the index of abdominal obesity. RESULTS: Baseline blood pressure was positively associated with waistahip ratio in men, but ambulatory blood pressure and heart rate were not independently related to waistahip ratio or job control. However, blood pressure and heart rate recorded during the working day and evening were elevated in men with high waistahip ratio who experienced low job control, independently of age and body weight. Effects for diastolic blood pressure and heart rate were replicated after 12 months. Body mass index was not related to blood pressure or heart rate during the day or evening after adjustment for age and waist circumference. Low job control was associated with poor psychological well-being, negative mood and lack of social support. CONCLUSIONS: The results are consistent with the hypothesis that abdominal obesity in men is characterised by a tendency towards heightened stress-induced physiological activation, but that this tendency will only be manifest in the presence of appropriate environmental challenges such as chronic work stress.

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Ambulatory blood pressure monitoring: a critical review of the current methods to handle outliers

Cited by 39 publications

References 0 publications

Heritability of Daytime Ambulatory Blood Pressure in an Extended Twin Design

Heritability of Daytime Ambulatory Blood Pressure in an Extended Twin Design

Ambulatory heart rate is underestimated when measured by an ambulatory blood pressure device

The influence of abdominal obesity and chronic work stress on ambulatory blood pressure in men and women

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