Day-night Blood Pressure Changes Research Articles

Chronic Kidney Disease and Left Ventricular Hypertrophy. Potent Modifiers of the Prognostic Impact of Circadian Blood Pressure Changes.

It is unclear whether the prognostic value of blood pressure (BP) changes from day to night is modified by concomitant risk factors and organ damage. We studied 3247 clinically hypertensive patients who underwent off-therapy 24-hour ambulatory BP monitoring during their initial diagnostic work-up. Over a mean 9.9-year follow-up, 292 patients developed a first primary outcome event (composite of nonfatal myocardial infarction, nonfatal stroke, cardiovascular death, hospitalization for heart failure) and 281 died. The day-night BP changes were analyzed as night-to-day systolic BP ratio and included in semiparametric Cox models. After allowance for age, sex, diabetes, cigarette smoking, low-density lipoprotein cholesterol, serum uric acid and average 24-hour systolic BP, the night-to-day systolic BP ratio maintained an independent association with outcome (hazard ratio, 1.17 [1.01-1.35]; P=0.041). When 2 markers of organ damage, chronic kidney disease and left ventricular hypertrophy, were added to the model, the night-to-day systolic BP ratio failed to maintain an independent association with outcome (hazard ratio, 1.19 [0.97-1.31]). The Akaike Information Criterion and the Schwarz-Bayes Information Criterion showed that, after allowance for other covariables, the night-to-day systolic BP ratio: (1) provided less information when compared with chronic kidney disease and left ventricular hypertrophy and (2) did not improve information provided by chronic kidney disease and left ventricular hypertrophy. Results were comparable on all-cause death as well as using categories of the night-day systolic BP ratio (extreme dippers, dippers, nondippers, reverse dippers). Chronic kidney disease and left ventricular hypertrophy are potent modifiers of the prognostic value of the circadian BP changes.

Dipping pattern and short-term blood pressure variability are stronger predictors of cardiovascular events than average 24-h blood pressure in young hypertensive subjects.

The role of increased blood pressure (BP) variability and a blunted day-night BP drop is still being debated, particularly in young hypertensive subjects. We investigated the contribution of BP variability and day-night BP changes combined to cardiovascular events in initially untreated young hypertensive individuals. We selected 1794 subjects aged ≤45 years from the HARVEST and the PIUMA studies, two long-term observational studies in subjects with hypertension. The outcome was a composite pool of non-fatal myocardial infarction or stroke, heart failure needing hospitalization, death from cardiovascular causes, and myocardial or limb revascularization procedures. During an 11.3-year follow-up, 140 cardiovascular events were accrued. A multivariable Cox model which included BP variability and non-dipping was more informative (Akaike Information Criterion = 1536.9) than the model which included average of 24-h BP (Akaike Information Criterion = 1553.6). A higher hazard ratio (HR) was observed for non-dipping [HR 2.22; 95% confidence interval (CI): 1.55-3.17; P < 0.0001] and for high BP variability (HR 1.84; 95% CI: 1.26-2.65; P = 0.0015) than for high average 24-h BP (HR 1.58; 95% CI: 1.07-2.33; P = 0.020). When average 24-h ambulatory BP was included in a nested model, the -2log likelihood decreased from 1524.9 to 1519.3, and there was a tendency for an interactive effect between 24-h BP and non-dipping on risk of cardiovascular events (P = 0.092). In young hypertensive individuals, prognostic models including BP variability and non-dipping pattern provide better information than models with average 24-h ambulatory BP alone. More consideration should be given to BP variability and the day-night BP pattern beyond the average 24-h ambulatory BP in young hypertensive subjects.

Blood Pressure, Heart Rate Variability, and Renal Function in Nonsmoker and Smoker Hypertensive Patients.

Blood Pressure, Heart Rate Variability, and Renal Function in Nonsmoker and Smoker Hypertensive Patients.

Negative Influence of HIV Infection on Day-Night Blood Pressure Variability

An attenuation of the physiological day-night blood pressure (BP) reduction is an important predictor of cardiovascular (CV) events and death. We compared circadian BP profile in treatment-naive HIV-infected patients and in healthy control subjects. Fifty-two antiretroviral therapy-naive HIV-infected patients (85% men, age 39 ± 11 years, BP 125/78 ± 11/9 mm Hg) and 156 age- and BP-matched HIV-negative controls (85% men, age 39 ± 10 years, BP 125/78 ± 9/7 mm Hg) underwent 24-hour BP monitoring. Subjects with a nocturnal reduction of systolic BP <10% were defined as "nondippers." Nighttime BP was higher in HIV-infected subjects (113/69 ± 11/9 vs 109/67 ± 8/6 mm Hg, P = 0.008/0.005). Nocturnal systolic/diastolic BP reduction was 8.8/13.2% in HIV-positive patients and 11.7/17.2% in HIV negative (P = 0.002/0.001). The prevalence of "nondippers" was 35% and 15%, respectively (P = 0.003). In multivariate analysis, nocturnal systolic BP fall was negatively associated to HIV infection (β = -0.22, P = 0.001). HIV viral load, low CD4 cell count, and AIDS progression risk were all related with a flattened day-night BP profile (P < 0.01). HIV infection per se negatively affects circadian BP rhythm. These findings, obtained in subjects without major CV risk factors and antiretroviral naive, suggest that day-night BP changes may play a role in the HIV-related increase in CV risk.

ADVERSE EFFECTS OF HIV INFECTION ON DAY-NIGHT BLOOD PRESSURE VARIABILITY: PP.14.29

Objective: An attenuation of the physiological day-night blood pressure (BP) reduction is an important predictor of cardiovascular events and death. Human immunodeficiency virus (HIV) infection has been linked with atherosclerotic cardiovascular complications, irrespective of antiretroviral therapy. It is unclear whether patients with HIV infection have an attenuated nocturnal BP reduction. Design: Cross-sectional case-control study, case:control matching ratio 1:3. Methods: Fifty-two antiretroviral therapy-naïve-HIV-infected patients (85% men, age 39 ± 11 years, BP 125/78 ± 11/9 mmHg) and 156 age- and BP-matched healthy controls (85% men, age 39 ± 10 years, BP 125/78 ± 9/7 mmHg) underwent 24-hour BP monitoring. Hypertension, diabetes, cardiovascular and renal disease, obesity, treatment with vasoactive drugs were exclusion criteria. Subjects with a nocturnal reduction of systolic BP <10% were defined as nondippers. Results: Average daytime BP did not differ in HIV and control subjects (124/80 ± 11/9 vs 124/79 ± 9/7 mmHg, p = n.s.). Nighttime BP was higher in HIV-infected subjects (113/69 ± 11/9 vs 109/67 ± 8/6 mmHg, p = 0.008/0.005). As shown in the Figure, nocturnal systolic/diastolic BP reduction was 8.8/13.2% in cases and 11.7/17.2% in controls (p = 0.002/0.001). The prevalence of nondippers was 35% in cases and 15% in controls (p = 0.003). In a multivariate analysis, nocturnal systolic BP fall was predicted by HIV infection (β=-0.22, p = 0.001). HIV viral load, low CD4 + cell count and AIDS progression risk were all related with a flattened day-night BP profile (p < 0.01). Conclusions: HIV infection per se influences negatively circadian BP rhythm. These findings, obtained in subjects without major cardiovascular risk factors and antiretroviral naive, suggest that day-night BP changes may play a role in HIV-related increase in cardiovascular risk.

Adrenergic, Metabolic, and Reflex Abnormalities in Reverse and Extreme Dipper Hypertensives

Limited information is available on whether and to what extent the different patterns of the nocturnal blood pressure profile reported in hypertension are characterized by differences in sympathetic drive that may relate to, and account for, the different day-night blood pressure changes. In 34 untreated middle-aged essential hypertensive dippers, 17 extreme dippers, 18 nondippers, and 10 reverse dippers, we assessed muscle sympathetic nerve traffic, heart rate, and beat-to-beat arterial blood pressure at rest and during baroreceptor deactivation and stimulation. Measurements were also performed in 17 age-matched dipper normotensives. All patients displayed reproducible blood pressure patterns at 2 different monitoring sessions. The 4 hypertensive groups did not differ by gender or 24-hour or daytime blood pressure. Muscle sympathetic nerve traffic was significantly higher in nondipper, dipper, and extreme dipper hypertensives than in normotensive controls (58.6+/-1.8, 55.6+/-0.9, and 53.3+/-0.8 versus 43.5+/-1.4 bursts/100 heartbeats, respectively; P<0.01 for all), a further significant increase being detected in reverse dippers (76.8+/-3.1 bursts/100 heartbeats; P<0.05). Compared with normotensives, baroreflex-heart rate control was similarly impaired in all the 4 hypertensive states, whereas baroreflex-sympathetic control was preserved. The day-night blood pressure difference correlated inversely with sympathetic nerve traffic (r=-0.76; P<0.0001) and homeostasis model assessment index (r=-0.32; P<0.005). Thus, the reverse dipping state is characterized by a sympathetic activation greater for magnitude than that seen in the other conditions displaying abnormalities in nighttime blood pressure pattern. The present data suggest that in hypertension, sympathetic activation represents a mechanism potentially responsible for the day-night blood pressure difference.

Is the definition of daytime and nighttime blood pressure prognostically relevant?

Although the prognostic value of the day-night blood pressure (BP) changes is well established, the most appropriate method for definition of daytime and nighttime BP is still undefined. In a recent guidelines document of the European Society of Hypertension, there is no clear position in favor of one definition over other. In the setting of the Progetto Ipertensione Umbria Monitoraggio Ambulariale study, we analyzed the prognostic impact of the day-night BP changes by using three widely used different definitions of day and night (large fixed-clock intervals, narrow fixed-clock intervals, diary) in 2934 initially untreated participants with essential hypertension. Three hundred and fifty-six cardiovascular events and 176 deaths over a median follow-up period of 7 years were observed. Nondippers showed a higher risk of total cardiovascular events and all-cause mortality than dippers regardless of the definition of day and night. Furthermore, the area under a receiver-operated characteristic curve analysis did not differ among the different definitions of day and night (large fixed-clock intervals, narrow fixed-clock intervals, diary) for total cardiovascular events and all-cause mortality (all P=NS). The data suggest that the prognostic value of the diurnal BP changes is comparable when day and night are defined using large fixed-clock intervals, narrow fixed-clock intervals, or actual time spent in and out of bed.

Prognostic value of circadian blood pressure changes in relation to differing measures of day and night

Although the prognostic value of the day-night blood pressure (BP) changes is established, the most appropriate method for defining day and night is undefined. We assessed the prognostic value of the day-night BP changes by using three definitions of day and night in 2,934 initially untreated hypertensive subjects who underwent 24-hour ambulatory BP monitoring. Over a median follow-up period of 7 years, there were 356 cardiovascular events and 176 deaths. Total cardiovascular events and all-cause mortality were similarly higher in non-dippers (night/day ratio of systolic BP >10% or >0%) than in dippers regardless of the definition of day and night. In a receiver-operated characteristic (ROC) curve analysis of the night/day ratio of systolic BP on the occurrence of events, the area under the ROC curve did not differ among the different definitions of day and night (large fixed-clock intervals, narrow fixed-clock intervals, diary) for both total cardiovascular events (0.61 [95% confidence interval (CI): 0.58 to 0.64], 0.61 [95% CI: 0.57 to 0.63], 0.62 [95% CI: 0.58 to 0.65], respectively; P = 0.20) and all-cause mortality (0.65 [95% CI: 0.61 to 0.70], 0.64 [95% CI: 0.60 to 0.69], 0.65 [95% CI: 0.61 to 0.70], respectively; P = 0.78). The prognostic value of the diurnal BP changes is comparable when using different clock-dependent or independent definitions of day and night.

Sleep and Hypertension

Even though sleep is widely considered to be a restorative and refreshing process, it is characterized by complex activity of the cardiovascular autonomic mechanisms and by relevant changes of arterial pressure and heart rate. It has been widely reported that fluctuations and variability of cortical and visceral activities involve a differential autonomic regulation of the cardiovascular system in relationship to different sleep cycles. During non–rapid eye movement (REM) sleep, arterial pressure and heart rate tend to decrease, whereas periods of relative hypertension and tachycardia characterize REM periods. With regard to the cardiovascular autonomic modulation, non-REM sleep is characterized by a vagal predominance, whereas during REM sleep, a relative increase in sympathetic activity is demonstrated by an increased sympathetic outflow to muscle blood vessels.1–3 See p 849 Therefore, this continuous cycling of non-REM and REM phases, with the consequent cardiovascular autonomic changes, makes sleep a period of considerable physiological turbulence characterized by sudden and abrupt blood pressure and heart rate changes. This cardiovascular instability has stimulated the investigation of the neural mechanisms involved in maintaining the cardiovascular homeostasis during the different sleep phases. The first pivotal study conducted with the Oxford technique in normotensive and hypertensive subjects4 clearly showed that changes in baroreflex function investigated by quantifying the reflex RR interval lengthening in response to a pharmacologically induced increase in systolic blood pressure (obtained through intravenous injection of phenylephrine), occurred ongoing from wakefulness to sleep. These changes consisted of an increase in the reflex sensitivity and of a resetting, moving the operating point of the reflex toward lower blood pressure values.4 In the past few years, this issue has been further investigated because it is now possible to investigate the arterial baroreflex function by analyzing the correlated blood pressure and spontaneous heart rate …

Day-night blood pressure changes and life quality at menopause hypertensive women

Day-night blood pressure changes and life quality at menopause hypertensive women

Predictors of diurnal blood pressure changes in 2042 subjects with essential hypertension

To determine the independent predictors of day-night blood pressure changes in a large population of subjects with essential hypertension. We studied 2042 white untreated subjects with essential hypertension (mean age 52 years, range 17-93, 1052 men) who underwent 24 h ambulatory blood pressure monitoring on an outpatient basis. Night-time workers were excluded from analysis. For both sexes, the changes in systolic and diastolic blood pressures from day to night decreased progressively with age and increased with the reported duration of sleep. The 1207 employed subjects who underwent ambulatory blood pressure monitoring during a usual working day had greater day-night blood pressure differences than did those who did not work (16.2 versus 14.0%). By using multiple regression analysis we assessed the independent association of several variables with the diurnal blood pressure changes. Age and diabetes for both sexes, and clinic blood pressure in men, were inversely associated with the nocturnal fall in blood pressure. The duration of sleep and the occurrence of blood pressure monitoring during a normal work day predicted a greater day-night blood pressure difference for both sexes; smoking predicted a greater nocturnal fall in blood pressure for women. Age is associated with an important and progressive attenuation of the day-night blood pressure difference in untreated and unrestricted subjects with essential hypertension. Other factors influencing diurnal blood pressure variations include clinic blood pressure, diabetes, the reported duration of sleep, smoking habits and working activity during blood pressure monitoring. These factors should be treated as potential confounders in the analysis of the relationship between diurnal blood pressure changes and target organ damage or prognosis.

Age and daytime activity influence day-night blood pressure changes in essential hypertension

Age and daytime activity influence day-night blood pressure changes in essential hypertension

Gender, day-night blood pressure changes, and left ventricular mass in essential hypertension: Dippers and peakers

The finding of increased left ventricular (LV) mass in hypertensive subjects with blunted nocturnal fall in blood pressure (BP) might be an artifact of matching patients for daytime BP, with resulting higher 24-h BP in nondippers. Therefore, we compared a large number (n = 1048) of hypertensive dippers and nondippers in their LV mass at echocardiography before and after adjustment for 24-h, daytime, and nighttime ambulatory BP. In men, the difference between dippers and nondippers was not significant before and after adjustment for 24-h BP, but after adjustment for nighttime BP LV mass was greater in dippers (more properly "peakers"). In women, LV mass was greater in nondippers than in dippers both before and after adjustment for 24-h BP, while the difference between the two groups disappeared after adjustment for nighttime BP. Thus, for any given level of mean 24-h BP, a flattened diurnal BP profile is associated with a greater LV mass in hypertensive women. Daytime hypertension, either associated or not with a blunted nocturnal fall in BP, may be a sufficient determinant of LV wall thickening in men.

Loss of Nocturnal Decline of Blood Pressure in Hypertension due to Chronic Renal Failure

The aim of this study was to assess the blood pressure profile of chronic renal failure in comparison with essential hypertension. Thirty hypertensive patients with chronic renal failure due to non-vascular nephropathies were matched by age, sex, and mean 24 h blood pressure, with 30 patients affected by uncomplicated mild-to-moderate essential hypertension. They were studied in an open hospital ward. Diet, meal times, sleep times, and activity schedules were standardized. Noninvasive, automatic, blood pressure recordings were performed for 48 h at sampling intervals of 15 min. The mean 24 h blood pressure almost coincided in the two groups. However, in essential hypertension a mean (+/- SD) nocturnal fall of systolic and diastolic blood pressure was found (12.7 +/- 3.8 and 12.9 +/- 4.8 mm Hg, respectively), while renal patients displayed an average nocturnal increase of 2.7 +/- 8.9 mm Hg and 3.7 +/- 7.8 (P less than .001). The renal patients had also higher heart rates, with a significantly blunted nocturnal fall (4.4 +/- 4.5 beats/min as compared to 9.3 +/- 3.1 beats/min of essential hypertension; P less than .001). Among the renal patients, the day-night blood pressure changes showed no significant correlation with age, creatinine clearance, hematocrit, nocturnal change in heart rate, or day or night mean blood pressure levels. These data suggest that an abnormal day-night pattern of blood pressure is present in chronic renal failure patients independently from external interfering factors. Hence, casual measurements of blood pressure confined to daytime may underestimate a hypertensive condition associated with chronic renal failure.

Experience with 24-hour ambulatory blood pressure monitoring in hypertension

Traditional sphygmomanometric blood pressure measurements may lead to errors in the diagnosis of arterial hypertension due to a number of factors, among which are the alerting reaction and pressor response induced in patients by the doctor's visit. This phenomenon, as quantified in our laboratory by continuous intraarterial recordings, is responsible for an average rise in systolic and diastolic blood pressure of 27 15 mm Hg , a rise that does not seem to be reduced by simply desensitizing the patient by means of more frequent physician visits. Twenty-four hour ambulatory blood pressure monitoring may theoretically improve the diagnostic approach to hypertensive patients by overcoming some limitations of isolated cuff measurements. In recording intraarterial blood pressure in 108 ambulant hypertensive subjects, we have found that 24-hour blood pressure values are able to discriminate among patients with different degrees of target organ damage better than isolated sphygmomanometric readings. Moreover, these studies have indicated that 24-hour blood pressure variability may be as important as blood pressure mean values in the assessment of cardiovascular complications. In clinical practice, however, intraarterial blood pressure monitoring is not feasible, and only noninvasive recorders can be used. Use of these devices does not induce any alerting reaction in the patients and does not interfere with day-night blood pressure changes. Although it is characterized by intermittent readings, this approach is not incompatible with a precise estimate of 24-hour blood pressure mean values. However, the discontinuous measurements provided by the presently available noninvasive devices do not allow the precise assessment of blood pressure variability and these measurements are characterized by a considerable degree of inaccuracy when used in ambulant subjects. These limitations, combined with the lack of prospective demonstrations of the diagnostic superiority of ambulatory blood pressure monitoring over office blood pressure readings, still suggest caution in recommending a generalized use of this nevertheless promising approach to the clinical management of hypertension.