TIME-WEIGHTED VS CONVENTIONAL QUANTIFICATION OF 24 HOUR AVERAGE AMBULATORY SYSTOLIC BLOOD PRESSURE (original) (raw)
Clinical Significance of the Blood Pressure Changes from Day to Night
Blood pressure (BP) decreases by 10% to 20% from day to night. However, in 25% to 35% of hypertensive subjects there is some reduction in the day-night BP decline. In 3% to 5% of uncomplicated hypertensive subjects there is actually an increase, not a decrease, in BP from day to night. Many studies from independent centers showed that not only left ventricular hypertrophy, but also ventricular arrhythmias, silent cerebrovascular disease, microalbuminuria and progression of renal damage are more advanced in subjects with blunted or abolished fall in BP from day to night than in those with normal day-night BP difference. There is also evidence from longitudinal studies that a blunted, abolished or even reversed BP drop from day to night is associated with an increase in the risk of serious cardiovascular complications. However, if the quantity or quality of sleep is poor during overnight BP monitoring, night-time BP rises and its prognostic significance is no longer reliable. Studies which compared the prognostic value of daytime BP with that of night-time BP inevitably found the superiority of the latter for predicting prognosis. The exciting potential therapeutic implication that the control of night-time BP could be more rewarding, in terms of prevention of cardiovascular disease, than that of daytime BP has yet to be addressed in appropriately designed intervention trials. Of note, 24-hour ABP monitoring is the only practical way to assess the day-night rhythm of BP.
Is blood pressure during the night more predictive of cardiovascular outcome than during the day?
Blood Pressure Monitoring, 2008
The objective of this study was to investigate the prognostic significance of the ambulatory blood pressure (BP) during night and day and of the night-to-day BP ratio (NDR). We studied 7458 participants (mean age 56.8 years; 45.8% women) enrolled in the International Database on Ambulatory BP in relation to Cardiovascular Outcome. Using Cox models, we calculated hazard ratios (HR) adjusted for cohort and cardiovascular risk factors. Over 9.6 years (median), 983 deaths and 943 cardiovascular events occurred. Nighttime BP predicted mortality outcomes (HR, 1.18-1.24; P < 0.01) independent of daytime BP. Conversely, daytime systolic (HR, 0.84; P < 0.01) and diastolic BP (HR, 0.88; P < 0.05) predicted only noncardiovascular mortality after adjustment for nighttime BP. Both daytime BP and nighttime BP consistently predicted all cardiovascular events (HR, 1.11-1.33; P < 0.05) and stroke (HR, 1.21-1.47; P < 0.01). Daytime BP lost its prognostic significance for cardiovascular events in patients on antihypertensive treatment. Adjusted for the 24-h BP, NDR predicted mortality (P < 0.05), but not fatal combined with nonfatal events. Participants with systolic NDR of at least 1 compared with participants with normal NDR ( Z 0.80 to < 0.90) were older, at higher risk of death, but died at higher age. The predictive accuracy of the daytime and nighttime BP and the NDR depended on the disease outcome under study. The increased mortality in patients with higher NDR probably indicates reverse causality. Our findings support recording the ambulatory BP during the whole day.
2014
The association of ambulatory blood pressure (BP) variability with mortality and cardiovascular events is controversial. To investigate whether BP variability predicts cardiovascular events and mortality in hypertension, we analyzed 7112 untreated hypertensive participants (3996 men) aged 52±15 years enrolled in 6 prospective studies. Median followup was 5.5 years. SD of night-time BP was positively associated with age, body mass index, smoking, diabetes mellitus, and average night-time BP (all P<0.001). In a multivariable Cox model, night-time BP variability was an independent predictor of all-cause mortality (systolic, P<0.001/diastolic, P<0.0001), cardiovascular mortality (P=0.008/<0.0001), and cardiovascular events (P<0.001/<0.0001). In contrast, daytime BP variability was not an independent predictor of outcomes in any model. In fully adjusted models, a night-time systolic BP SD of ≥12.2 mm Hg was associated with a 41% greater risk of cardiovascular events, a 55% greater risk of cardiovascular death, and a 59% increased risk of all-cause mortality compared with an SD of <12.2 mm Hg. The corresponding values for a diastolic BP SD of ≥7.9 mm Hg were 48%, 132%, and 77%. The addition of night-time BP variability to fully adjusted models had a significant impact on risk reclassification and integrated discrimination for all outcomes (relative integrated discrimination improvement for systolic BP variability: 9% cardiovascular events, 14.5% all-cause death, 8.5% cardiovascular death, and for diastolic BP variability: 10% cardiovascular events, 19.1% all-cause death, 23% cardiovascular death, all P<0.01). Thus, addition of BP variability to models of long-term outcomes improved the ability to stratify appropriately patients with hypertension among risk categories defined by standard clinical and laboratory variables. (Hypertension. 2014;64:487-493.) • Online Data Supplement (P.V.). The online-only Data Supplement is available with this article at http://hyper.ahajournals.org/lookup/suppl/
Journal of Hypertension, 2010
Objective To assess whether modifications in the nighttime blood pressure fall caused by antihypertensive treatment predict the regression of end-organ damage of hypertension. The analysis was performed in patients with essential hypertension and echocardiographically detected left ventricular hypertrophy involved in the SAMPLE study. For each patient, ambulatory blood pressure monitoring and echocardiographic determination of left ventricular mass index were performed at the end of a 4-week wash-out pretreatment period, after 3 and 12 months of treatment with lisinopril or with lisinopril plus hydrochlorothiazide and after a final 4-week placebo period. For each ambulatory blood pressure monitoring the 24 h average, daytime average (0600-2400 h), night-time average (2400-0600 h) and day-night difference was computed. The percentages of dipper and non-dipper patients (i.e. the patients with night blood pressure falls greater and less than 10% of the daytime average, respectively) were also computed. The reproducibility of the day-night difference was low, both for comparison of the pretreatment and final placebo periods (n = 170) and for comparison of the third and the 12th month of treatment (n = 180). The reproducibility of the dipper-non-dipper dichotomy was also low, 35-40% of patients becoming non-dippers if they were dippers and vice versa, both with and without treatment. The changes in left ventricular mass index after 12 months of treatment were significantly (P < 0.01) related to the changes in 24 h, daytime and night-time blood pressure (r always > 0.33), but this was not the case for the treatment-induced modification of the day-night difference (r = -0.03 and -0.008 for systolic and diastolic blood pressures, respectively). Our results show that day-night blood pressure changes and the classification of patients into dippers and non-dippers are poorly reproducible over time. It also provides the first prospective evidence that treatment-induced changes in day-night blood pressure difference are not related to treatment-induced regression of left ventricular mass index, thus having a limited clinical significance.
Reproducibility of ambulatory blood pressure changes from the initial values on two different days
Clinics, 2013
We tested the reproducibility of changes in the ambulatory blood pressure (BP) from the initial values, an indicator of BP reactivity and cardiovascular health outcomes, in young, healthy adults. METHOD: The subjects wore an ambulatory BP monitor attached by the same investigator at the same time of day until the next morning on two different days (day 1 and day 2) separated by a week. We compared the ambulatory BP change from the initial values at hourly intervals over 24 waking and sleeping hours on days 1 and 2 using linear regression and repeated measures analysis of covariance. RESULTS: The subjects comprised 88 men and 57 women (mean age¡SE 22.4¡0.3 years) with normal BP (118.3¡0.9/69.7¡0.6 mmHg). For the total sample, the correlation between the ambulatory BP change on day 1 vs. day 2 over 24, waking, and sleeping hours ranged from 0.37-0.61; among women, the correlation was 0.38-0.71, and among men, it was 0.24-0.52. Among women, the ambulatory systolic/diastolic BP change was greater by 3.1¡1.0/2.4¡0.8 mmHg over 24 hours and by 3.0¡1.1/2.4¡0.8 mmHg over waking hours on day 1 than on day 2. The diastolic ambulatory BP change during sleeping hours was greater by 2.2¡0.9 mmHg on day 1 than on day 2, but the systolic ambulatory BP change during sleeping hours on days 1 and 2 did not differ. Among men, the ambulatory BP change on days 1 and 2 did not differ. CONCLUSION: Our primary findings were that the ambulatory BP change from the initial values was moderately reproducible; however, it was more reproducible in men than in women. These results suggest that women, but not men, may experience an alerting reaction to initially wearing the ambulatory BP monitor.
Nocturnal blood pressure fall on ambulatory monitoring in a large international database
1997
A wide range of definitions is used to distinguish subjects in whom blood pressure (BP) falls at night (dippers) from their counterparts (nondippers). In an attempt to standardize the definition of nondipping, we determined the nocturnal BP fall and night-day BP ratio by 24-hour ambulatory monitoring in 4765 normotensive and 2555 hypertensive subjects from 10 to 99 years old. In all subjects combined, the systolicldiastolic nocturnal fall and corresponding ratio averaged ('SD)-16.7t 11.01-13.628.1 mm Hg and 87.258.0%183.1f 9.6%, respectively. In normotensive subjects, the 95th percentiles were-0.31-1.1 mm Hg for the nocturnal fall and 99.7%198.3% for the night-day ratio. Both the fall and ratio showed a curvilinear correlation with age. The smallest fall and largest ratio were observed in older (2 7 0 years) subjects. A higher BP on conventional sphygmomanometry was associated with a larger systolic (partial r=.l l) and diastolic (r=.12) nocturnal BP fall. The diastolic (r=.O8) but not the systolic night-day ratio increased with higher conventional BP. The nocturnal BP fall was larger and the corresponding night-day ratio smaller in oscillometric (n=5884) than in auscultatory (n=1436) recordings, in males (n=3730) than in females (n=3590), and in Europe (n=4556) than in the other continents (n=2764). The distributions of the nocturnal BP fall and night
American Journal of Hypertension, 2000
An absent or diminished blood pressure (BP) fall during sleep (so-called "nondipping") has been associated with a higher risk of cardiovascular complications, but the long-term reproducibility of dipper status and the relationship between diurnal changes in BP and perceived sleep quality have not been previously documented in untreated hypertensive patients. Ambulatory BP (ABP) and dipping status were examined in 79 subjects (69 hypertensives and 10 normotensives) at 0, 6, and 12 months. Fifty-six percent of subjects had no change in their dipping status, the majority (53%) dipping normally on all three occasions. However, 44% of patients had variable dipping status, and normal nighttime dipping in BP was observed more often when patients perceived their sleep quality to be good during the period of ABP recording. These results highlight significant intrasubject variability in the diurnal fluctuations in ABP and dipper status, which may in part reflect day-today variations in sleep disturbance during ABP monitoring. Classifying hypertensive patients into dippers or nondippers on the basis of a single ABP recording is unreliable and potentially misleading.
Circadian Blood Pressure Profile and Associated Cardiovascular Risk Factors in Non-Dippers
2020
Introduction: Ambulatory blood pressure accurately reflects a patient's actual blood pressure than casual or office blood pressure. This study aims to describe the circadian blood pressure profile of hypertensive patients and to identify the associated cardiovascular risk factors in non-dippers. Methods: A cross-sectional study was conducted from 1st January 2008 to 30th June 2008 among hypertensive patients attending Family Medicine Clinic HUSM. Schiller BR-102 plus was used to get 24 hours blood pressure (BP) reading. Mean of two offices BP were also taken. Non-dippers are defined as a systolic or diastolic nocturnal drop of less than 10%. Analysis was done using SPSS Version 12. Results: 105 patients were recruited with mean (SD) age of 51.8 (9.34) year old. The mean (SD) 24-hour systolic and diastolic BP was 128.4 (12.7) mmHg and 79.7 (8.74) mmHg respectively. Mean (SD) daytime systolic and diastolic BP was 132.1 (11.72) mmHg and 82.4 (9.41) mmHg while for the night time were 123.3 (12.78) mmHg and 76.2 (9.01) mmHg. Mean (SD) systolic and diastolic office BP was 144.2(15.16) mmHg and 90.2(9.71) mmHg. Percentage of non dippers were 68.6% for systolic and 61.9% for diastolic. Conclusion: Mean 24 hours and daytime ambulatory BP was normal but the mean night time diastolic and office BP was above-normal value. Majority of the patients were categorized as non dippers. Therefore, using ambulatory BP is clinically important to get a better understanding of blood pressure fluctuations over 24-hour periods compared to simple clinical measurements.