Sleep Blood Pressure Research Articles

A primary care pragmatic cluster randomized trial of the use of home blood pressure monitoring on blood pressure levels in hypertensive patients with above target blood pressure

The measurement of blood pressure (BP) at home by patients with hypertension is increasingly used to assess and monitor BP. Evidence for its effectiveness in improving BP control is mixed. To determine if home BP monitoring improves BP a pragmatic cluster randomized contolled trial was carried out in family practices in southeastern Ontario, Canada. Family practice patients with uncontrolled hypertension were recruited to the trail. Patients were divided into two groups: one with at least weekly measurements of BP at home, recording those measurements and showing those to the family physician during office visits for hypertension and the control group were given usual care. The primary outcome was mean awake BP on ambulatory monitoring at 6- and 12-month follow-up and the secondary outcomes were mean BP on full 24-hour ambulatory blood pressure monitoring (ABPM), mean sleep BP on ABPM and BP on the BpTRU device, all at 6- and 12-month follow-up. Home BP monitoring did not improve BP compared to usual care at 12-month follow-up: mean awake systolic BP on ABPM [141.1 versus 142.8 mmHg, mean difference 1.7 mmHg; 95% confidence interval (CI) -0.6 to 4.0, P = 0.314] and mean awake diastolic BP on ABPM (78.7 versus 79.4 mmHg, mean difference 0.7 mmHg; 95% CI -7.7 to 9.1, P = 0.398). Similar negative results were obtained for men and women separately. However, outcomes using the full 24-hour ABPM and the BpTRU device showed a significantly lower diastolic BP at 12 months. When analysis was done by sex, this effect was shown to be only in men. Home BP monitoring may improve BP control in men with hypertension.

Relationship between sleep apnea syndrome and sleep blood pressure in patients without hypertension

Ambulatory blood pressure monitoring (ABPM) provides an accurate assessment of blood pressure (BP) and shows non-dipper BP pattern in many sleep apnea syndrome (SAS) patients with hypertension (HTN); however, little information is available on the relationship between the severity of SAS and circadian BP changes in SAS patients without HTN. This study investigated whether SAS patients without HTN would have different BP courses in the severity of SAS. Seventy-four consecutive outpatients without HTN [systolic BP (BPs) at clinic <140mmHg and/or diastolic BP (BPd) at clinic <90mmHg], who received no antihypertensives, underwent overnight polysomnography (PSG) and ABPM. The apnea-hypopnea index (AHI) was calculated from the PSG results; patients were stratified into the following 4 groups based on their AHI: non-SAS, mild-, moderate-, or severe-SAS. The diurnal BPs and BPd showed no differences in the severity of SAS; however, the sleep BPs, lowest BPs, and pre-awake BPs were significantly higher in the severe-SAS group than the non-SAS group (p=0.02, p=0.04, and p=0.006, respectively). The sleep BPd and pre-awake BPd were significantly higher in the severe-SAS than the non-SAS (p=0.01 and p=0.0003, respectively) and mild-SAS (p=0.01 and p=0.008, respectively) groups. The results of this study suggested that SAS affected nocturnal BP elevation even in SAS patients without HTN. The diurnal BP showed no difference in the severity of SAS; however, the severe-SAS group revealed significant nocturnal BP elevation.

White-Coat Hypertension Should Not Be Treated in Subjects With Diabetes

Blood pressure (BP) levels in the doctor's clinic may not always reflect those of daily living, as indicated by 24-h ambulatory or self-monitoring measurements. Simple logic implies that treatment should be guided by the actual BP levels, rather than by imprecise clinic measurements. On average, BP measured in the clinic is higher than out-of-office BP. This difference occurs in a considerable number of patients with white-coat hypertension (WCH). The issue is complicated, since most studies define WCH as an elevated office BP in patients with normal awake ambulatory BP. However, the “awake” state may not fully reflect the 24-h BP load. Average 24-h BP, and particularly that during sleep, which is more likely to be higher in subjects with diabetes (1,2), could be elevated in a patient with normal awake BP. The presence of abnormal clinic BP in such a patient discloses true hypertension rather than WCH. Indeed, among 4,121 subjects referred for ambulatory BP monitoring, 4.5% had isolated abnormal sleep BP (>120/70 mmHg) and normal 24-h BP (3). Nevertheless, in this presentation, we assume that the common definition of WCH is elevated clinic readings with normal awake BP. Assessment of WCH in diabetes is complicated by the fact that normal BP measured at the clinic is defined as <130/80 mmHg (as opposed to 140/90 mmHg in the general population), whereas there are still no accepted thresholds for ambulatory or home-based BP levels. Characteristics unique to the white-coat response in patients with diabetes, associated prognostic implications, and the need for treatment are discussed. The issue of prevalence is not marginal: we have found that compared with subjects without diabetes who were referred for 24-h ambulatory BP monitoring, those treated for diabetes were less likely to have WCH (and more likely to have masked hypertension) (1). A similar conclusion …

Reduction of morning blood pressure surge after treatment with nifedipine GITS at bedtime, but not upon awakening, in essential hypertension

The extent of morning blood pressure (BP) surge upon wakening has been associated with increased incidence of stroke and cardiovascular mortality. This trial investigated the antihypertensive efficacy and effects on the morning BP surge of awakening versus bedtime administration of nifedipine in essential hypertension. We studied 238 previously untreated hypertensive patients (108 men and 130 women), 53.3+/-11.4 years of age, randomly assigned to receive nifedipine (30 mg/day) as a monotherapy either upon awakening or at bedtime. BP was measured for 48 h before and after 8 weeks of treatment. The BP reduction after the treatment was significantly greater with bedtime dosing (P<0.001). The proportion of patients with controlled ambulatory BP thus increased from 28 to 43% (P = 0.019) with bedtime treatment. The sleep time relative BP decline was unchanged after morning treatment, but increased toward a more dipping pattern after bedtime dosing (P = 0.026 between groups). The morning BP surge was unchanged after the administration of nifedipine upon awakening (1.4/1.2 mmHg reduction in systolic/diastolic BP surge, P>0.270), but significantly reduced after bedtime dosing (6.2/4.4 mmHg reduction, P<0.001). Nifedipine efficiently reduces BP for the entire 24 h and to a significantly larger extent after bedtime administration. The significant added efficacy on reducing night-time BP, the decrease in the prevalence of a nondipper BP pattern, and the significant decrease in morning BP surge (all relevant markers of cardiovascular morbidity and mortality) of bedtime as compared with morning administration, consistently indicate that nifedipine should preferably be administered at bedtime in patients with essential hypertension.

Early Morning Surge and Dipping Status of Blood Pressure: Are These of Predictive Value for Silent Myocardial Ischemia?

To investigate the predictive value of morning surge (MS) and dipping status of blood pressure (BP) for ST-segment depression (ST depression) in hypertensive persons, the combined 24-hour ambulatory BP measurement and Holter electrocardiographic recordings of 344 patients (132 women and 212 men, 60+/-12 years) were analyzed. The morning BP surge was calculated as mean systolic BP during the 2 hours after awaking minus the mean systolic BP during the 1 hour that included the lowest sleep BP. Depending on the percentage decrease in systolic BP at night, patients were subdivided into extreme dippers, dippers, nondippers, and risers. ST depression was defined as horizontal or descending ST depression of 1 mm of 1 minute duration and a 1-minute interval after the previous episode or 24-hour mean ST-segment value <-0.1 mV. ST depression was observed in 76 (22.1%) of 344 patients. The mean MS in patients with ST depression was with 25+/-15 mm Hg and not significantly different when compared with patients without ST depression (26+/-15 mm Hg). The prevalence of ST depression was not significantly different in dippers, extreme dippers, nondippers, and risers (20%, 23.5%, 23%, and 25.5%, respectively). Systolic and diastolic BP values during ST depression were significantly higher in the morning as compared with ST depression in the evening (149/84 mm Hg vs 138/78 mm Hg, P<.05). In the present study, MS and dipping status of BP were not associated with ST depression. ST depression was, however, characterized by significantly higher BP peaks in the early morning hours.

Volume-Associated Ambulatory Blood Pressure Patterns in Hemodialysis Patients

Although volume excess causes hypertension, whether it also affects circadian patterns of arterial pressures among hemodialysis patients remains unknown. To test the notion of whether volume overload is associated with a unique blood pressure (BP) "signature," a posthoc analysis was performed among 145 patients participating in the Dry-Weight Reduction in Hypertensive Hemodialysis Patients randomized, controlled trial. Using 400 ambulatory BP recordings over 8 weeks composed of 35 302 measurements, the trended cosinor model was found to be the best descriptor of BP chronobiology. The trended cosinor model may be described as a pattern of sinusoidal oscillation around a straight line with an upward trend during the interdialytic period that has an intercept at the postdialysis time. Augmented volume removal therapy reduced the intercept systolic BP and increased the rate of rise in systolic BP over the interdialytic interval but had no effect on the systolic BP fluctuation (amplitude). Thus, an elevated intercept and blunted slope pattern characterize the "volume-overload BP pattern" on ambulatory BP monitoring. Similar changes were seen for diastolic BP. Augmented volume removal therapy neither restored dipping nor was associated with a lag phenomenon for either the wake or the sleep systolic BP. Lowering of systolic BP was greater than diastolic BP such that pulse pressure was reduced. An observational cohort of 37 patients followed for 6 months confirmed these findings. Randomized trials are now needed to evaluate the clinical impact of augmented volume removal therapy on hard outcomes, because reduction of pulse pressure with this simple expedient has the potential to improve survival in hemodialysis patients.

Management of nocturnal hypertension

Nocturnal hypertension is a common complication of essential and secondary hypertension. Abnormal circadian blood pressure patterns associated with elevated sleep blood pressure include nondipping and reverse dipping, both of which are associated with increased target-organ damage and adverse cardiovascular outcomes. Nocturnal hypertension can be treated with several approaches that include both lifestyle changes, such as sodium restriction and potassium supplementation, and pharmacological treatments, primarily through the use of bedtime dosing of antihypertensive agents. Evening administration of blockers of the renin–angiotensin–aldosterone system is the most consistently effective of these treatment strategies. In this review, we provide a detailed discussion of the options available for the management of nocturnal hypertension.

Does It Matter When Drugs Are Taken?

Blood pressure varies throughout the day, being highest on awakening in the morning and lowest during sleep. However, the sleep blood pressure predicts cardiovascular and cerebrovascular ischemic events better than the awake blood pressure, which predicts hemorrhagic strokes.1 Thus, the level of blood pressure interacts with the hormonal environment to determine the outcome. Similar observations have been made in rats in which the blood pressure during sleep is the principal determinant of cardiac enlargement.2 A conclusion is that control of sleep blood pressure may be more important than control of awake blood pressure, although ideally blood pressure should be controlled throughout 24 hours. Relatively little attention has been paid to the time at which drugs should be administered, and, in general, the ideal is thought to be that they can be taken once a day and usually in the morning, because this is believed to improve compliance. This policy may lead to major undertitration of drugs, particularly those that have a short half-life or duration of action. Thus, the response to enalapril 5, 10, 20 or 40 mg is similar 3 to 4 hours after administration, but the 2 lower doses have little effect 24 hours later. The policy of taking the medication in the morning, particularly if the patient is seen 2 to 3 hours later, leads to a failure to control blood pressure during sleep and during the awakening hours, which probably compose the most critical period. A similar problem applies to most of the angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers, …

Exaggerated morning blood pressure surge and cardiovascular events. A 5-year longitudinal study in normotensive and well-controlled hypertensive elderly

Cardiovascular events (CE) occur most frequently in the morning hours in hypertensive subjects. We studied the association between the morning blood pressure (BP) surge and CE in prognosis of 10 normotensive and 32 well-controlled hypertensive elderly, in whom ambulatory BP monitoring was performed and who were followed prospectively for 5 years. The morning surge (MS) of BP was calculated as mean systolic BP during 2h after awakening−mean systolic BP during 1h that included the lowest sleep BP. During an average of 60 months, five CE occurred. When the patients were divided into two groups according to MS, those in the top terzile (MS group; MS≥34 mmHg, n=14) had a higher prevalence of CE (5 versus 0, p=0.001) during the follow-up period, than the others (non-MS group; MS<34 mmHg, n=28). The logistic regression analysis showed the MS sleep-trough surge as predictive variable of CE (odds ratio, OR=0.794, p=0.022). In conclusion, in older normotensives and well-controlled hypertensives, a higher BP MS is associated with vascular risk independently of clinical and ambulatory BP. Reduction of the MS could thus be a therapeutic target for preventing vascular events also in non-hypertensive patients.

576: Do the second trimester ambulatory 24-hour, awake and sleep blood pressure measurements correlate with placental weight in women at risk for hypertension in pregnancy?

Our aim was to assess the correlation between placental weight and the average 24-hour ambulatory blood pressure measurement (24-ABPM), awake (A-ABPM) and sleep (S-ABPM) in patients at risk for hypertension (HTN) in pregnancy. To our knowledge this is the first study attempting to analyze these relationships.

233: Do the second trimester ambulatory 24-hour, awake and sleep blood pressure measurements correlate with infant birth weight in women at risk for hypertension in pregnancy?

233: Do the second trimester ambulatory 24-hour, awake and sleep blood pressure measurements correlate with infant birth weight in women at risk for hypertension in pregnancy?

Effects of Habitual Alcohol Intake on Ambulatory Blood Pressure, Heart Rate, and Its Variability Among Japanese Men

We sought to examine effects of habitual alcohol intake on ambulatory blood pressure (BP), heart rate (HR), and HR variability among Japanese men. Subjects were 539 men aged 35 to 65 years from rural and urban communities. Ambulatory BP and HR were monitored with an automated, portable, noninvasive multibiomedical recorder. Power spectral analysis of the RR intervals on the ECG was performed every 5 minutes. Compared with nondrinkers, moderate drinkers (alcohol intake 23 to 45 g/d) and heavy drinkers (alcohol intake >or=46 g/d) showed higher age- and field-adjusted mean values of systolic and diastolic BPs during the morning and while awake, but there were no differences in BPs over 24-hour periods and while asleep among the alcohol intake categories. Alcohol intake was positively associated with mean values of sleep-morning differences and daytime variability in BPs, HRs while awake and asleep, and low frequency:high frequency ratio while asleep. The results were virtually unchanged after adjustment for body mass index, smoking, and diabetes mellitus. Compared with the nondrinkers, age- and field-adjusted odds ratios of the morning BP surge (excess elevation of BP in the morning: morning systolic BP minus sleep systolic BP >or=37 mm Hg) for light (alcohol intake 0 to 22 g/d), moderate, and heavy drinkers were 0.96 (95% CI: 0.34 to 2.78), 1.68 (95% CI: 0.64 to 4.38), and 2.73 (95% CI: 1.12 to 6.67), respectively. Habitual alcohol intake was associated with increased BP in the morning, HR while awake and asleep, and sympathetic activity while asleep, which may explain some of the mechanisms of the relationship between heavy alcohol intake and risk of cardiovascular diseases.

Relationship between waking–sleep blood pressure and catecholamine changes in African–American and European–American women

A blunted decline in waking to sleep blood pressure (BP) is more common in African-American (AA) than European-American (EA) women. The causes of reduced BP 'dipping' in AA women are not known, although several factors including ethnic differences in catecholamine sensitivity have been suggested. The purpose of this study was to investigate the possible contribution of catecholamine influences on BP to ethnic differences in BP dipping in a sample of working women. Healthy female participants wore ambulatory BP monitors over the course of 1 work day and night. Urine samples for assay of epinephrine and norepinephrine were collected at work (approximately 11.00-15.00 h), home (approximately 06.00-22.00 h) and during sleep (approximately 22.00-06.00 h). Analysis of covariance was used to assess the relationships between changes in BP and the catecholamines by ethnicity. AA women (n=51; age=38.9+/-8.5 years) had smaller proportional BP changes from work to sleep and home to sleep than EA women (n=110; age=37.1+/-9.2 years). Overall, the work to sleep change in epinephrine excretion was positively associated with changes in both SBP (P<0.003) and DBP (P<0.001); however, there was an ethnic difference in the epinephrine-BP relationship. For AA women, these associations were highly positive and significant, but for EA women, there was little correlation. Nonetheless, the analysis also revealed that overall, the work to sleep BP changes were not directly related to ethnic differences in catecholamine variation. The AA-EA difference in waking-sleep BP changes (dipping) is not directly related to ethnic differences in catecholamine variation; however, AA seem to have a greater BP sensitivity to epinephrine.

Magnitude of the early morning blood pressure surge in untreated hypertensive patients: a pooled analysis

A post hoc analysis was performed to assess the magnitude of the early morning blood pressure surge (EMBPS), which is associated with peak cardiovascular risk, in untreated hypertensive patients enrolled in two sister studies (Prospective, Randomised Investigation of the Safety and efficacy of MICARDIS vs. ramipril using ambulatory blood pressure monitoring I and II) with identical design. In adults with a mild-to-moderate primary hypertension and no significant comorbidities, 24-h ambulatory blood pressure monitoring was conducted after a 2- to 4-week placebo run-in period and before treatment initiation. Individual blood pressure measurements at 20-min intervals were analysed. In 1419 hypertensive patients with normal sleeping times, blood pressure displayed a typical circadian rhythm, with a mean EMBPS of 29/24 mmHg. An EMBPS of >or= 25 mmHg was observed in around 60% of patients. The surge was significantly increased with smoking, alcohol consumption, longer sleep, later waking times, and increased blood pressure variability during waking and sleeping. The magnitude of the EMBPS was significantly reduced in Black vs. White patients. The surge was not affected by gender, body mass index or duration of hypertension. Further analysis showed that ethnicity, alcohol consumption and smoking were all found to have a significant impact on surge around waking and age, sleep duration and sleep blood pressure variability were all found to have an effect on the prewake surge. In untreated hypertensive patients, the magnitude of the EMBPS is significant when compared with the 24-h mean and is affected by individual patient characteristics. In light of these findings, physicians should understand the importance of 24-h blood pressure control and the modification of certain lifestyle factors as ways of reducing the EMBPS.

Sex Differences in Ambulatory Blood Pressure Monitoring

Purpose Referral to ambulatory blood pressure monitoring may have bearing upon blood pressure control and prognosis. We describe sex-related differences in referral for ambulatory monitoring and their prognostic impact. Methods Between 1991 and 2005, 3957 patients were monitored in our ambulatory monitoring service, of whom 2114 (53%) were women. Demographic and clinical data were analyzed according to sex. Results Age (58 ± 15 vs 52 ± 17 years, respectively) and body mass index (27.5 ± 4.9 vs 26.9 ± 4.0 kg/m 2, respectively) were higher in women than men. Treatment for hypertension was more prevalent in women (62% vs 53%, respectively). Clinic systolic blood pressure (148 ± 24 vs 146 ± 20 mm Hg, respectively) and clinic pulse pressure (65 ± 22 vs 59 ± 18 mm Hg, respectively) were higher in women compared with men. In women, the white-coat effect was increased, compared with men; 5.2 ± 12.4% vs 1.5 ± 10.7% systolic, and 5.4 ± 11.2% vs 3.6 ± 10.3% diastolic. Consequently, women had lower ambulatory blood pressure than men. In women, 24-hour blood pressure was 136 ± 17/76 ± 10 vs 140 ± 15/81 ± 10 mm Hg in men, awake blood pressure 141 ± 17/80 ± 11 vs 144 ± 15/84 ± 10 mm Hg, and sleep blood pressure was 125 ± 19/67 ± 10 vs 127 ± 18/71 ± 11 mm Hg. Age-adjusted ambulatory blood pressure also was lower in women. Ambulatory heart rate was higher in women ( P <.0001). Kaplan-Meier survival did not differ by sex ( P = .66), despite older age and higher clinic blood pressure. Conclusions The results might imply that referral was driven by the physicians' overall patient risk perception. The greater magnitude of white-coat effect in women, and correspondingly lower ambulatory blood pressure, might in part account for similar mortality in the face of older age and higher clinic blood pressure.

Ambulatory blood pressure in children with obstructive sleep apnoea: a community based study

Background:Childhood obstructive sleep apnoea (OSA) is increasingly being recognised. Its effects on blood pressure (BP) elevation and hypertension are still controversial.Objective:To evaluate the association between OSA and ambulatory BP in...

Sleep-Predominant Lowering of Ambulatory Blood Pressure by Bedtime Inhalation of a Novel Muscarinic M3 Receptor Antagonist: A New “Bronchoantihypertensive” Strategy Targeting the Lung in Hypertension with Chronic Obstructive Pulmonary Disease

Bedtime inhalation of a novel muscarinic M3 receptor antagonist markedly lowered ambulatory blood pressure (ABP), predominantly during sleep, in a chronic obstructive pulmonary disease (COPD) patient with masked nocturnal hypertension. This is the first case demonstrating that a bronchodilator significantly lowered ABP in a COPD patient with hypertension. This case suggests that bronchodilator therapy may have potential as a new antihypertensive strategy targeting the lung in hypertensive patients with impaired lung function. This "bronchoantihypertensive" therapy seems to be more effective for reducing sleep blood pressure in hypertensive patients with COPD and sleep hypoventilatory/hypoxemic syndromes.

IMPORTANCE OF SLEEP BLOOD PRESSURE

1. Blood pressure varies throughout the day and night and is maintained at different times by different control systems. 2. During the awake interval, the sympathetic nervous system is preeminent but during sleep the renin angiotensin system is the controller. 3. Sleep blood pressure is a more powerful predictor of non-haemorrhagic cerebro- and cardiovascular events in animals and humans, despite the sleep value being lower than the day value. 4. Drugs that act independently of the hormonal or neural systems, such as diuretics and calcium channel blockers, have similar effects during sleep and awake intervals. Beta-blockers have little effect during sleep when the activity of the sympathetic is low while drugs that interfere with the action of the renin angiotensin system have a greater blood pressure lowering effect during sleep. 5. One aim of therapy should be to ensure that blood pressure is low during sleep and drugs should be used in doses that lower blood pressure throughout the 24 h period.

Response to Interstudy Variability of Ambulatory Arterial Stiffness Index

We thank Dechering et al1 for their comments on our study, in which we revealed a previously unobserved strong negative association between the degree of nocturnal blood pressure (BP) reduction and ambulatory arterial stiffness index (AASI).2 Dechering et al1 observe that the night:day ratio of BP measurements is able to explain part of the interstudy variability in AASI: the lower the number of nocturnal as compared with diurnal readings, the higher the AASI (see Table 1 in Reference 1). The dependency of AASI on the number of diurnal and nocturnal readings is a phenomenon related to our demonstration2 that day-night BP reduction is …

Predictors of All-Cause Mortality in Clinical Ambulatory Monitoring

The prognostic value of sleep blood pressure reported by recent studies is variable. Our aim was to examine the relationship of sleep blood pressure, measured by 24-hour ambulatory blood pressure monitoring, with all-cause mortality. We studied a cohort of 3957 patients aged 55+/-16 (58% treated) referred for ambulatory monitoring (1991-2005). Sleep, including daytime sleep, was recorded by diary. Linkage with the national population register identified 303 deaths during 27 750 person-years of follow-up. Hazard ratios (HRs) for mortality in Cox proportional hazards models that included age, sex, hypertension, and diabetes treatment were 1.32 (95% CI: 0.99 to 1.76) for awake hypertension (>or=135/85 mm Hg), and 1.67 (95% CI: 1.25 to 2.23) for sleep hypertension (>or=120/70 mm Hg). By quintile analysis, the upper fifths of systolic and diastolic dipping during sleep were associated with adjusted HRs of 0.58 (95% CI: 0.41 to 0.82) and 0.68 (95% CI: 0.48 to 0.96), respectively. In a model controlling for awake systolic blood pressure, hazards associated with reduced systolic dipping increased from dippers (>10%; HR: 1.0), through nondippers (0% to 9.9%; HR: 1.30; 95% CI: 1.00 to 1.69) to risers (<0%; HR: 1.96; 95% CI: 1.43 to 2.96). Thus, in practice, ambulatory blood pressure predicts mortality significantly better than clinic blood pressure. The availability of blood pressure measures during sleep and, in particular, the pattern of dipping add clinically predictive information and provide further justification for the use of ambulatory monitoring in patient management.