Short-term and long-term repeatability of the morning blood pressure in older patients with isolated systolic hypertension

Controversies in Hypertension III: Dipping, Nocturnal Hypertension, and the Morning Surge

A comprehensive approach to hypertension requires out-of-office determinations by home and/or ambulatory monitoring. The 4 phenotypes comparing office and out-of-office pressures in treated and untreated patients include normotension, hypertension, white-coat phenomena, and masked phenomena. Components of out-of-office pressure may be equally as important as mean values. Nighttime pressures are normally 10 - 20% lower than daytime (normal "dipping"). Abnormalities include dipping more than 20% (extreme dippers), less than 10 % (non-dippers), or rising above daytime (risers) and have been associated with elevated cardiovascular risk. Nighttime pressure may be elevated (nocturnal hypertension) in isolation or together with daytime hypertension. Isolated nocturnal hypertension theoretically changes white-coat hypertension to true hypertension and normotension to masked hypertension. Pressure normally peaks in the morning hours ("morning surge") when cardiovascular events are most common. Morning hypertension may result from residual nocturnal hypertension or an exaggerated surge and has been associated with enhanced cardiovascular risk, especially in Asian populations. Randomized trials are needed to determine whether altering therapy based solely on either abnormal dipping, isolated nocturnal hypertension, and/or an abnormal surge is justified.

Clinical information from repeated blood pressure measurements in the management of heart failure with preserved ejection fraction

It remains unclear whether cumulative blood pressure (BP) exposure is associated with adverse outcomes in heart failure with preserved ejection fraction (HFpEF). The aim was to investigate the associations of adverse health outcomes with cumulative BP exposure as captured by weighted BP, cumulative BP and trends in BP over a 1-year timespan from baseline to a 12-month visit among 1303 patients with HFpEF (49.5% women; mean age, 71.5 years) enrolled in the TOPCAT (Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist) trial. The primary endpoints consisted of death from cardiovascular causes, aborted cardiac arrest, or hospitalization for the management of heart failure.We computed hazard ratios with a 1-SD increase in weighted BP and cumulative BP. In the spironolactone group, compared with patients with a downward trend in BP, those with an upward trend had higher event rates. However, there were no differences in event rates between those with upward and downward trends in BP in the placebo group. In multivariable-adjusted analyses that additionally accounted for baseline BP, weighted systolic BP and cumulative systolic BP predicted (P ≤ 0.037) the primary composite endpoint (hazard ratio [HR], 1.21; 95% CI, 1.05-1.39/1.15; 1.01-1.31) and hospitalization for HF (1.29; 1.09-1.52/1.18; 1.02-1.37), respectively. Among patients aged ≤72 years, cumulative systolic BP increased (P ≤ 0.016) the risk of the primary endpoint and hospitalization for HF. Higher cumulative systolic BP exposure conferred a higher risk of the primary endpoint and hospitalization for HF, independent of baseline BP. Our findings underscore that longitudinal BP measurements may refine risk stratification for patients with HFpEF.

Role of home blood pressure monitoring in resistant hypertension

The definition of resistant hypertension (RHT) has been updated to include failure to achieve target blood pressure (BP) despite treatment with ≥3 antihypertensive drugs, including diuretics, renin-angiotensin system blockers, and calcium channel blockers, prescribed at the maximum or maximally tolerated doses, or as success in achieving the target blood pressure but requiring ≥4 drugs. RHT is a major clinical problem, as it is associated with higher mortality and morbidity than non-RHT. Therefore, it is crucial to accurately identify RHT patients to effectively manage their disease. Out-of-clinic BP measurement, including home BP monitoring and ambulatory BP monitoring is gaining prominence for the diagnosis and management of RHT. Home BP monitoring is advantageous as it is feasibly repetitive, inexpensive, widely available, and because of its reproducibility over long periods. In addition, home BP monitoring has crucial advantage of allowing safe titration for the maximum or maximally tolerable dose, and for self-monitoring, thereby improving clinical inertia and nonadherence, and allowing true RHT to be more accurately identified.

Within-Person Blood Pressure Variability During Hospitalization and Clinical Outcomes Following First-Ever Acute Ischemic Stroke

BACKGROUND

Uncertainty remains over the relationship between blood pressure (BP) variability (BPV), measured in hospital settings, and clinical outcomes following acute ischemic stroke (AIS). We examined the association between within-person systolic blood pressure (SBP) variability (SBPV) during hospitalization and readmission-free survival, all-cause readmission, or all-cause mortality 1 year after AIS.

METHODS

In a cohort of 862 consecutive patients (age [mean ± SD] 75 ± 15 years, 55% women) with AIS (2005-2018, follow-up through 2019), we measured SBPV as quartiles of standard deviations (SD) and coefficient of variation (CV) from a median of 16 SBP readings obtained throughout hospitalization.

RESULTS

In the cumulative cohort, the measured SD and CV of SBP in mmHg were 16 ± 6 and 10 ± 5, respectively. The hazard ratios (HR) for readmission-free survival between the highest vs. lowest quartiles were 1.44 (95% confidence interval [CI] 1.04-1.81) for SD and 1.29 (95% CI 0.94-1.78) for CV after adjustment for demographics and comorbidities. Similarly, incident readmission or mortality remained consistent between the highest vs. lowest quartiles of SD and CV (readmission: HR 1.29 [95% CI 0.90-1.78] for SD, HR 1.29 [95% CI 0.94-1.78] for CV; mortality: HR 1.15 [95% CI 0.71-1.87] for SD, HR 0.86 [95% CI 0.55-1.36] for CV).

CONCULSIONS

In patients with first AIS, SBPV measured as quartiles of SD or CV based on multiple readings throughout hospitalization has no independent prognostic implications for the readmission-free survival, readmission, or mortality. This underscores the importance of overall patient care rather than a specific focus on BP parameters during hospitalization for AIS.

Association Between Morning Surge in Systolic Blood Pressure and SYNTAX Score I in Patients With Stable Coronary Artery Disease

A high morning surge in systolic blood pressure poses a risk in people who have cardiovascular disease. We investigated the relationship between this phenomenon and the SYNTAX score I in patients who had stable coronary artery disease. Our single-center study included 125 consecutive patients (109 men and 16 women; mean age, 54.3 ± 9 yr) in whom coronary angiography revealed stable coronary artery disease. We calculated each patient's sleep-trough morning surge in systolic blood pressure, then calculated the SYNTAX score I. The morning surge was significantly higher in patients whose score was >22 (mean, 22.7 ± 13.2) than in those whose score was ≤22 (mean, 12.4 ± 7.5) (P <0.001). Forward stepwise logistic regression analysis revealed that morning surge in systolic blood pressure was the only independent predictor of an intermediate-to-high score (odds ratio=1.183; 95% CI, 1.025-1.364; P=0.021). To our knowledge, this is the first study to show an association between morning surge in systolic blood pressure and the SYNTAX score I in patients who have stable coronary artery disease.

The Association of Morning Surge and Night-Time Dipping Blood Pressure with Significant and Complex Coronary Artery Lesions

INTRODUCTION

Hypertension responsible for more than 10 million deaths annually worldwide and abnormal diurnal blood pressure (BP) variation is associated with cardiovascular events.

AIM

This study aimed to investigate the association between the 24-h ambulatory night BP dipping and morning BP surge (MS) with characteristic of coronary artery lesions that may contribute cardiovascular events and mortality burden.

METHODS

A cross sectional study over 1-year, collected 263 cases of hypertensive (80%) and non-hypertensive patients, aged 61 ± 10 years, who undergoing invasive coronary angiography (CAG) and 24-h ambulatory BP monitoring admitted to cardiology department complain of chest pain. The night-time/day-time dip and sleep-trough MS were calculated. Non-dipper status was considered when night-time/day-time dip < 10%, and significant coronary lesion (SCL) when ≥ 50 % stenosis in 1.5 mm vessels. The SYNTAX (Synergy Between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery) score was used to quantify the complexity of SCL.

RESULT

The mean morning systolic BP (SBP) surge was higher in the high SYNTAX Score subgroup than low and intermediate subgroups (25 ± 11 vs 17 ± 13 and 10 ± 10 mmHg, p < 0.010). Non-dipper SBP status was more frequently in patients with SCL than non-SCL (p < 0.019). In ordinal regression, hypertension was independent predictor of SCL (odd ratio: 0.40, p < 0.003), the night-time/day-time BP dip was independent predictor of being in a higher SYNTAX score subgroup (systolic odd ratio: 0.88, diastolic odd ratio: 1.14 p < 0.05).

CONCLUSION

Hypertension is associated with SCL and the night-time/day-time BP dip as a continuous variable is associated with complex coronary lesion. Non-dipping as categorical variable and morning BP surge were not independent predictors of significant or complex coronary lesions.

Morning Blood Pressure Surge and Cardiovascular Disease Events and All-Cause Mortality in Blacks: The Jackson Heart Study

The cardiovascular disease (CVD) and mortality risk associated with morning blood pressure (BP) surge and its components among black adults, a population with high BP during the asleep period, is unknown. We studied Jackson Heart Study participants who completed 24-hour ambulatory BP monitoring at the baseline exam in 2000 to 2004 (n=761). The sleep-trough morning surge was calculated as the mean 2-hour postawakening systolic BP (SBP) minus the lowest nighttime SBP, preawakening morning surge as mean 2-hour postawakening SBP minus mean 2-hour preawakening SBP, and rising morning surge as the first postawakening SBP minus the last preawakening SBP. The primary outcome was the occurrence of CVD events including the composite of coronary heart disease or stroke. Over a median follow-up of 14.0 years, there were 74 CVD (coronary heart disease or stroke) events and 144 deaths. Higher tertiles of sleep-trough, preawakening, and rising SBP surge were not associated with CVD risk after multivariable adjustment. In contrast, the highest tertile of the individual components of morning surge, including postawakening SBP (tertiles 2 and 3 versus 1: hazard ratio [95% CI]: 1.58 [0.71-3.53] and 4.04 [1.91-8.52], respectively), lowest nighttime SBP (1.29 [0.59-2.84] and 2.87 [1.41-5.83]), preawakening SBP (1.26 [0.57-2.80] and 2.79 [1.32-5.93]), first postawakening SBP (1.60 [0.73-3.51] and 2.93 [1.40-6.16]), and last preawakening SBP (1.23 [0.57-2.68] and 2.99 [1.46-6.12]), was associated with increased CVD risk after multivariable adjustment. Among black adults, the components of morning SBP surge, but not morning SBP surge itself, were associated with increased CVD risk.

Outcome-Driven Thresholds for Ambulatory Blood Pressure Based on the New American College of Cardiology/American Heart Association Classification of Hypertension

The new American College of Cardiology/American Heart Association guideline reclassified office blood pressure and proposed thresholds for ambulatory blood pressure (ABP). We derived outcome-driven ABP thresholds corresponding with the new office blood pressure categories. We performed 24-hour ABP monitoring in 11 152 participants (48.9% women; mean age, 53.0 years) representative of 13 populations. We determined ABP thresholds resulting in multivariable-adjusted 10-year risks similar to those associated with elevated office blood pressure (120/80 mm Hg) and stages 1 and 2 of office hypertension (130/80 and 140/90 mm Hg). Over 13.9 years (median), 2728 (rate per 1000 person-years, 17.9) people died, 1033 (6.8) from cardiovascular disease; furthermore, 1988 (13.8), 893 (6.0), and 795 (5.4) cardiovascular and coronary events and strokes occurred. Using a composite cardiovascular end point, systolic/diastolic outcome-driven thresholds indicating elevated 24-hour, daytime, and nighttime ABP were 117.9/75.2, 121.4/79.6, and 105.3/66.2 mm Hg. For stages 1 and 2 ambulatory hypertension, thresholds were 123.3/75.2 and 128.7/80.7 mm Hg for 24-hour ABP, 128.5/79.6 and 135.6/87.1 mm Hg for daytime ABP, and 111.7/66.2 and 118.1/72.5 mm Hg for nighttime ABP. ABP thresholds derived from other end points were similar. After rounding, approximate thresholds for elevated 24-hour, daytime, and nighttime ABP were 120/75, 120/80, and 105/65 mm Hg, and for stages 1 and 2, ambulatory hypertension 125/75 and 130/80 mm Hg, 130/80 and 135/85 mm Hg, and 110/65 and 120/70 mm Hg. Outcome-driven ABP thresholds corresponding to elevated blood pressure and stages 1 and 2 of hypertension are similar to those proposed by the current American College of Cardiology/American Heart Association guideline.

Bioinformatics Study on Serum Triglyceride Levels for Analysis of a Potential Risk Factor Affecting Blood Pressure Variability

Objective:

The purpose of this study was to establish whether Triglycerides (TGs) are related to Blood Pressure (BP) variability and whether controlling TG levels leads to better BP variability management and prevents Cardiovascular Disease (CVD).

Methods:

In this study, we enrolled 106 hypertensive patients and 80 non-hypertensive patients. Pearson correlation and partial correlation analyses were used to define the relationships between TG levels and BP variability in all subjects. Patients with hypertension were divided into two subgroups according to TG level: Group A (TG<1.7 mmol/L) and Group B (TG>=1.7 mmol/L). The heterogeneity between the two subgroups was compared using t tests and covariance analysis.

Results:

TG levels and BP variability were significantly different between the hypertensive and non-hypertensive patients. Two-tailed Pearson correlation tests showed that TG levels are positively associated with many BP variability measures in all subjects. After reducing other confounding factors, the partial correlation analysis revealed that TG levels are still related to the Standard Deviation (SD), Coefficient of Variation (CV) of nighttime systolic blood pressure and CV of nighttime diastolic blood pressure, respectively (each p<0.05). In the subgroups, group A had a lower SD of nighttime Systolic Blood Pressure (SBP_night_SD; 11.39±3.80 and 13.39±4.16, p=0.011), CV of nighttime systolic blood pressure (SBP_night_CV; 0.09±0.03 and 0.11±0.03, p=0.014) and average real variability of nighttime systolic blood pressure (SBP_night_ARV; 10.99±3.98 and 12.6±3.95, p=0.024) compared with group B, even after adjusting for age and other lipid indicators.

Conclusion:

TG levels are significantly associated with BP variability and hypertriglyceridemia, which affects blood pressure variability before causing target organ damage.

Comparison Between Home and Ambulatory Morning Blood Pressure and Morning Hypertension in Their Reproducibility and Associations With Vascular Injury

Morning blood pressure (BP) is recommended to be assessed by either 24-hour ambulatory or home BP monitoring. By which methods morning BP assessed is more reproducible and more closely associated with vascular injury remains unknown. We, therefore, addressed this issue in 1049 referred untreated outpatients (51.9% women; average age, 51 years) who had performed 24-hour ambulatory and 7-day home BP monitoring and vascular evaluations. Irrespective of the assessment methods, morning BPs were all significantly ( P≤0.027) associated with the arterial measures. The partial correlation coefficients of carotid-femoral pulse wave velocity and urinary albumin-to-creatinine ratio with home morning BPs were greater than those with the ambulatory morning pressures among the first 2 hours after awakening (0.21-0.37 versus 0.15-0.24; P<0.05). The associations with home morning systolic BP remained significant ( P≤0.002) after full adjustment for evening BP, whereas those with ambulatory morning BPs became nonsignificant after full adjustment for 24-hour BP except that of the carotid-femoral pulse wave velocity with ambulatory morning (6:00-10:00) systolic BP. Of the 135 subjects who had both home and repeated 24-hour ambulatory BP monitoring within 1 month, the coefficients of variation were ≈11% for ambulatory morning BPs and 5% for home self-measurements. In conclusion, morning BP, irrespective of the assessment methods and definitions, was generally reproducible and significantly associated with vascular indices. Nevertheless, home morning BP might be preferred than ambulatory measurements because of better reproducibility and stronger correlation with vascular indices.

Short-term reproducibility of the 24-h ambulatory monitoring of brachial and central hemodynamics in untreated Chinese

Objective: Advanced technology allows non-invasive monitoring of the 24-h brachial and central hemodynamics simultaneously. However, related reproducibility data was limited in White patients. We therefore explored if the novel measurements would be reproducible in Chinese. Methods: From February 2017 to January 2018, 152 untreated patients who were suspected of hypertension and referred for ambulatory blood pressure (BP) monitoring were recruited. Ambulatory BP monitoring was repeated within one month (median, 12.5 days) using the Mobil-O-Graph monitors (IEM, Germany). Reproducibility was assessed as the intra-class correlation coefficient (ICC), coefficient of variation (CV), and repeatability coefficient (RC). Results: The 152 participants (average age, 58.6 years) included 54 men and 98 women. The first and second means of the ambulatory brachial and central BPs, pulse wave velocity (PWV), augmentation pressure, augmentation index (AIx) and AIx at a heart rate of 75 beats per minute (AIx@75) were all similar (p ≥ 0.065), except that the repeated daytime and 24-h brachial and central systolic BPs and pulse pressure slightly differed by approximately 1-2 mmHg (p ≤ 0.011). ICC ranged from 0.70 to 0.94 for all ambulatory BPs and ≥0.91 for the arterial measurements. CV was in the range from 5.0% to 10.3% for all BPs and PWV measurements, and from 15.5% to 22.3% for AIx and AIx@75. RC expressed as percentages of maximal variation was <15% for the PWVs and ranged from 25.5% to 54.7% for BPs, AIx and AIx@75. Conclusions: The 24-h ambulatory brachial and central BPs and arterial measurements were reproducible within a short time period in Chinese, and could therefore be used in clinical practice and research settings.

Randomised controlled trial of a Calcium Channel or Angiotensin Converting Enzyme Inhibitor/Angiotensin Receptor Blocker Regime to Reduce Blood Pressure Variability following Ischaemic Stroke (CAARBS): a protocol for a feasibility study

INTRODUCTION

Raised blood pressure (BP) is common after stroke and is associated with a poor prognosis, yet trials of BP lowering in the immediate poststroke period have not demonstrated a benefit. One possible explanation for this may be that BP variability (BPV) rather than absolute levels predicts outcome, as BPV is increased after stroke and is associated with poor outcomes. Furthermore, there is evidence of distinct antihypertensive class effects on BPV despite similar BP-lowering effects. However, whether BPV in the immediate poststroke period is a therapeutic target has not been prospectively investigated.The objectives of this trial are to assess the feasibility and safety of recruiting patients following an acute ischaemic stroke or transient ischaemic attack (TIA) to an interventional randomised controlled trial comparing the effects of two different antihypertensive drug classes on BPV. Secondary exploratory objectives are to assess if different therapeutic strategies have diverse effects on levels of BPV and if this has an impact on outcomes.

METHODS

150 adult patients with first-ever ischaemic stroke or TIA who require antihypertensive therapy for secondary prevention will be recruited within 7 days of the event from stroke services across three sites. After baseline assessments they will be randomly assigned to treatment with a calcium channel blocker or ACE inhibitor/angiotensin receptor blocker-based regimen and followed up for a period of three months.

ETHICS AND DISSEMINATION

Ethical and regulatory approvals have been granted. Dissemination is planned via publication in peer-reviewed medical journals and presentation at relevant conferences.

TRIAL REGISTRATION NUMBER

ISRCTN10853487.

Understanding short-term blood-pressure-variability phenotypes: from concept to clinical practice

Clinic blood pressure (BP) is recognized as the gold standard for the screening, diagnosis, and management of hypertension. However, optimal diagnosis and successful management of hypertension cannot be achieved exclusively by a handful of conventionally acquired BP readings. It is critical to estimate the magnitude of BP variability by estimating and quantifying each individual patient's specific BP variations. Short-term BP variability or exaggerated circadian BP variations that occur within a day are associated with increased cardiovascular events, mortality and target-organ damage. Popular concepts of BP variability, including "white-coat hypertension" and "masked hypertension", are well recognized in clinical practice. However, nocturnal hypertension, morning surge, and morning hypertension are also important phenotypes of short-term BP variability that warrant attention, especially in the primary-care setting. In this review, we try to theorize and explain these phenotypes to ensure they are better understood and recognized in day-to-day clinical practice.

Morning blood pressure surge: pathophysiology, clinical relevance and therapeutic aspects

Morning hours are the period of the day characterized by the highest incidence of major cardiovascular events including myocardial infarction, sudden death or stroke. They are also characterized by important neurohormonal changes, in particular, the activation of sympathetic nervous system which usually leads to a rapid increase in blood pressure (BP), known as morning blood pressure surge (MBPS). It was hypothesized that excessive MBPS may be causally involved in the pathogenesis of cardiovascular events occurring in the morning by inducing hemodynamic stress. A number of studies support an independent relationship of MBPS with organ damage, cerebrovascular complications and mortality, although some heterogeneity exists in the available evidence. This may be due to ethnic differences, methodological issues and the confounding relationship of MBPS with other features of 24-hour BP profile, such as nocturnal dipping or BP variability. Several studies are also available dealing with treatment effects on MBPS and indicating the importance of long-acting antihypertensive drugs in this regard. This paper provides an overview of pathophysiologic, methodological, prognostic and therapeutic aspects related to MBPS.

Morning blood pressure monitoring in the management of hypertension

: The aim of the current article is to review the current evidence on the role of morning blood pressure (BP) in the management of hypertension. Morning BP surge had been and will continue to be a hot topic of hypertension research. However, more evidence is needed to prove its clinical usefulness in the management of hypertension. Masked morning hypertension, as the other forms of masked hypertension, requires more research. The concept of morning BP monitoring could be clinically relevant in the therapeutic management of hypertension and in the prevention of cardiovascular complications by defining and treating morning hypertension. Antihypertensive medication is usually taken in the morning. The presence of uncontrolled morning BP during trough effect hours could be a hallmark of inadequate antihypertensive regimen, such as, for instance, the use of short-acting or intermediate-acting drugs, under dosing of drugs, or no or low use of combination therapy. To improve the management of hypertension in general and morning hypertension in particular, long-acting antihypertensive drugs should be used in appropriate often full dosages and in proper combinations. The clinical usefulness of antihypertensive drugs of specific mechanisms against morning BP or split or timed dosing of long-acting drugs in controlling morning BP remains under investigation. In conclusion, there is some evidence that morning BP is critical in the incidence of cardiovascular complications. However, proving its clinical usefulness in the management of hypertension requires further research.

Prognostic Value of Nondipping and Morning Surge in Elderly Treated Hypertensive Patients With Controlled Ambulatory Blood Pressure

BACKGROUND

The independent prognostic significance of nondipping and morning surge (MS) of blood pressure (BP) in treated hypertensive patients with controlled ambulatory BP is not yet clear. We investigated the association between the aforesaid ambulatory BP parameters and cardiovascular risk in elderly treated hypertensive patients with normal achieved ambulatory BP.

METHODS

The occurrence of a composite end-point (stroke, coronary events, heart failure, and peripheral revascularization) was evaluated in 391 elderly treated hypertensive patients (age range 60-90 years) with controlled ambulatory BP (both daytime BP <135/85 mm Hg and nighttime BP <120/70 mm Hg). According to nighttime change and MS of systolic BP, subjects were divided in dippers with normal or high MS (>23 mm Hg) and nondippers.

RESULTS

During the follow-up (9.3 ± 4.6 years, range 0.5-20 years), 76 events occurred. The event-rate was 2.09 per 100 patient-years. After adjustment for age, gender, left ventricular (LV) hypertrophy, asymptomatic LV systolic dysfunction at baseline and left atrial enlargement, dippers with high MS (hazard ratio 2.45, 95% confidence interval 1.27-4.73, P = 0.007) and nondippers (hazard ratio 2.04, 95% confidence interval 1.18-3.53, P = 0.01) were at higher cardiovascular risk than dippers with normal MS.

CONCLUSIONS

In elderly treated hypertensive patients with normal achieved ambulatory BP, dippers with high MS and nondippers are at increased cardiovascular risk.

Novel Triggered Nocturnal Blood Pressure Monitoring for Sleep Apnea Syndrome: Distribution and Reproducibility of Hypoxia-Triggered Nocturnal Blood Pressure Measurements

Obstructive sleep apnea (OSA) causes blood pressure (BP) surges during sleep, which may lead to increased sleep-onset cardiovascular events. The authors recently developed a triggered nocturnal BP monitoring system that initiates BP measurements when oxygen desaturation falls below a variable threshold. The distribution and reproducibility of hypoxia-triggered nocturnal BP parameters compared with those of fixed-interval nocturnal BP parameters for two consecutive nights in 147 OSA patients (mean age 59.4 years, 86.4% men) were evaluated. The mean and distribution (standard deviation [SD]) of the hypoxia-peak systolic BP (SBP) were significantly greater than that of the mean nocturnal SBP (mean±SD: 148.8±20.5 vs 123.4±14.2 mm Hg, P<.001). The repeatability coefficient (expressed as %MV) of hypoxia-peak SBP between night 1 and night 2 was comparable to that of mean nocturnal SBP (43% vs 32%). In conclusion, hypoxia-peak nocturnal BP was much higher than mean nocturnal BP, and it was as reproducible as mean nocturnal BP.

Perfect 24-h management of hypertension: clinical relevance and perspectives

Out-of-office blood pressure (BP) measured by home BP monitoring, or ambulatory BP monitoring, was demonstrated to be superior to office BP for the prediction of cardiovascular events. The J-HOP study of a nationwide Japanese cohort demonstrated that morning home BP is the best stroke predictor. In the prospective HONEST study of >21 000 hypertensives, on-treatment morning home BP was shown to be a strong predictor both of future coronary artery disease and stroke events. In subjects whose office BP was maintained at ⩾150 mm Hg, there was no increase in cardiovascular events when their morning systolic BP was well-controlled at <125 mm Hg. Since Asians show greater morning BP surges, it is particularly important for Asians to achieve 'perfect 24-hr BP control,' that is, the 24-h BP level, nocturnal BP dipping and BP variability including morning surge. The morning BP surge and the extremes of disrupted circadian rhythm (riser and extreme dipper patterns) are independent risks for stroke in hypertensives. A morning BP-guided approach is thus the first step toward perfect 24-h BP control, followed by the control of nocturnal hypertension. In the resonance hypothesis, the synergistic resonance of BP variability phenotypes would produce an extraordinary large 'dynamic BP surge' that can trigger a cardiovascular event, especially in high-risk patients with systemic hemodynamic atherothrombotic syndrome, a vicious cycle of exaggerated BP variability and vascular disease. In the future, information and communications technology and artificial intelligence technology with the innovation of wearable continuous surge BP monitoring will contribute to 'anticipation medicine' with the goal of zero cardiovascular events.

Blood flow restriction training and the exercise pressor reflex: a call for concern

Blood flow restriction (BFR) training (also known as Kaatsu training) is an increasingly common practice employed during resistance exercise by athletes attempting to enhance skeletal muscle mass and strength. During BFR training, blood flow to the exercising muscle is mechanically restricted by placing flexible pressurizing cuffs around the active limb proximal to the working muscle. This maneuver results in the accumulation of metabolites (e.g., protons and lactic acid) in the muscle interstitium that increase muscle force and promote muscle growth. Therefore, the premise of BFR training is to simulate and receive the benefits of high-intensity resistance exercise while merely performing low-intensity resistance exercise. This technique has also been purported to provide health benefits to the elderly, individuals recovering from joint injuries, and patients undergoing cardiac rehabilitation. Since the seminal work of Alam and Smirk in the 1930s, it has been well established that reductions in blood flow to exercising muscle engage the exercise pressor reflex (EPR), a reflex that significantly contributes to the autonomic cardiovascular response to exercise. However, the EPR and its likely contribution to the BFR-mediated cardiovascular response to exercise is glaringly missing from the scientific literature. Inasmuch as the EPR has been shown to generate exaggerated increases in sympathetic nerve activity in disease states such as hypertension (HTN), heart failure (HF), and peripheral artery disease (PAD), concerns are raised that BFR training can be used safely for the rehabilitation of patients with cardiovascular disease, as has been suggested. Abnormal BFR-induced and EPR-mediated cardiovascular complications generated during exercise could precipitate adverse cardiovascular or cerebrovascular events (e.g., cardiac arrhythmia, myocardial infarction, stroke and sudden cardiac death). Moreover, although altered EPR function in HTN, HF, and PAD underlies our concern for the widespread implementation of BFR, use of this training mechanism may also have negative consequences in the absence of disease. That is, even normal, healthy individuals performing resistance training exercise with BFR are potentially at increased risk for deleterious cardiovascular events. This review provides a brief yet detailed overview of the mechanisms underlying the autonomic cardiovascular response to exercise with BFR. A more complete understanding of the consequences of BFR training is needed before this technique is passively explored by the layman athlete or prescribed by a health care professional.

Association between 24-hour blood pressure variability and chronic kidney disease: a cross-sectional analysis of African Americans participating in the Jackson heart study

Background

Studies suggest 24-h blood pressure (BP) variability has prognostic value for cardiovascular disease. Several factors associated with high 24-h BP variability are also common among individuals with chronic kidney disease (CKD). We hypothesized 24-h BP variability would be higher for individuals with versus without CKD.

Methods

We analyzed 1,022 Jackson Heart Study participants who underwent ambulatory blood pressure monitoring (ABPM). Twenty-four hour BP variability was defined by two metrics: day-night standard deviation (SD_dn) and average real variability (ARV). CKD was defined as ACR ≥30 mg/g or eGFR <60 mL/min/1.73 m².

Results

The mean SD_dn of systolic BP (SBP) was 10.2 ± 0.2 and 9.1 ± 0.1 mmHg and the mean ARV of SBP was 9.2 ± 0.2 and 8.6 ± 0.1 mmHg for those with and without CKD, respectively (each p ≤ 0.001). After adjustment for age and sex, SD_dn and ARV were 0.98 mmHg (95 % CI 0.59, 1.38) and 0.52 mmHg (95 % CI 0.18, 0.86), respectively, higher among participants with versus without CKD. These differences were not statistically significant after further multivariable adjustment including 24-h mean SBP. Older age, and higher total cholesterol and 24-h mean SBP were associated with higher SD_dn and ARV of SBP among participants with CKD. Mean SD_dn and ARV of diastolic BP (DBP) were higher for participants with versus without CKD but these associations were not present after multivariable adjustment.

Conclusion

Data from the current study suggest that CKD is associated with higher 24-h BP variability, but the association is primarily explained by higher mean BP among those with CKD.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-015-0085-6) contains supplementary material, which is available to authorized users.

Clinical significance of home blood pressure measurements for the prevention and management of high blood pressure

1. Ambulatory blood pressure (ABP) monitoring (M) provides BP information at many points on any particular day during unrestricted routine daily activities, whereas home blood pressure (HBP) monitoring provides a lot of BP information obtained under fixed times and conditions over a long period of time, thus mean values of HBP provide high reproducibility, and thus an overall superiority compared with ABP.  2. HBP is at least equally or better able than ABP to predict hypertensive target organ damage and prognosis of cardiovascular disease.  3. HBPM allows for ongoing disease monitoring by patients, improves adherence to antihypertensive treatment, and can provide health-care providers with timely clinical data and direct and immediate feedback regarding diagnosis and treatment of hypertension.  4. HBPM provides BP information in relation to time; that is, BP in the morning, in the evening and at night during sleep, and it is an essential tool for the diagnosis of white-coat and masked hypertension.  5. HBPM yields minimal alerting affects and no or minimal placebo effect, and can therefore distinguish small, but significant, serial changes in BP. It is thus the most practical method for monitoring BP in the day-to-day management of hypertension. 6. The superiority of HBPM over ABPM and clinic BPM is apparent from almost all practical and clinical research perspectives.

Blood pressure variability in risk stratification: What does it add?

1. In this minireview we address the predictive value of blood pressure variability, over and beyond level of pressure, in randomly selected population samples. All reviewed studies had sufficient power, long follow-up duration and a wide age range. 2. We assessed blood pressure variability derived from home visit, self-measured home pressure and 24 h ambulatory monitoring. The conclusions are based mainly on novel indices of blood pressure variability: variability independent of the mean, difference between maximum and minimum blood pressure and average real variability. 3. None of these variability indices or morning surge in blood pressure substantially refined risk profiling over and beyond the blood pressure level. 4. In risk stratification, clinicians should concentrate on blood pressure level, the predominant risk factor modifiable by lifestyle measures and antihypertensive drug treatment.

Relationship between elevated morning blood pressure surge, uric acid, and cardiovascular outcomes in hypertensive patients

Early morning blood pressure surge (MBPS) is a risk factor for cardiovascular events (CVEs), but the relationship with uric acid is not well understood. The authors aimed to determine the association between MBPS and increased uric acid and the effect of elevated MBPS and uric acid combination on CVEs. A total of 921 patients underwent 24-hour ambulatory blood pressure monitoring and were followed for a median of 40 months. During this period, 103 (11.2%) CVEs occurred. There was a significant relationship between increasing quartiles of serum uric acid level and increasing values of MBPS (P<.0001). Patients in the highest quartile stratified by elevated MBPS and serum uric acid level had a 3.55 odds of major CVE compared with patients in the lowest quartile. Serum uric acid is associated with MBPS and development of new CVEs.

Blood pressure control and primary prevention of stroke: summary of the recent clinical trial data and meta-analyses

Stroke is the second most common cause of death worldwide and of adult disability, but in the near future the global burden of cerebrovascular diseases will rise due to ageing and adverse lifestyle changes in populations worldwide. The risk of stroke increases at blood pressure levels above 115/75 mm Hg and high blood pressure (BP) is the most important modifiable risk factor for stroke, associated with 54 % episodes of stroke worldwide. There is strong evidence from clinical trials that antihypertensive therapy reduces substantially the risk of any type of stroke, as well as stroke-related death and disability. The risk attributed to BP is associated not only with absolute values but also with certain parameters describing BP diurnal pattern as well as short-term and long-term variability. Many studies reported that certain features of BP like nocturnal hypertension, morning surge or increased variability predict an increased stroke risk. However, there is no accepted effective modality for correction of these disturbances (chronotherapy, certain classes of antihypertensive drugs). In the elderly, who are mostly affected by stroke, the primary prevention guidelines recommend treatment with diuretics and calcium channel blockers to lower blood pressure to the standard level.

Morning blood pressure surge is associated with arterial stiffness and sympathetic baroreflex sensitivity in hypertensive seniors

Morning blood pressure (BP) surge is considered to be an independent risk factor for cardiovascular diseases. We tested the hypothesis that increased large-artery stiffness and impaired sympathetic baroreflex sensitivity (BRS) contribute to augmented morning surge in elderly hypertensive subjects. Morning surge was assessed as morning systolic BP averaged for 2 h just after waking up minus minimal sleeping systolic BP by using ambulatory BP monitoring (ABPM) in 40 untreated hypertensive [68 ± 1 (SE) yr] and 30 normotensive (68 ± 1 yr) subjects. Beat-by-beat finger BP and muscle sympathetic nerve activity (MSNA) were recorded in the supine position and at 60° upright tilt. We assessed arterial stiffness with carotid-to-femoral pulse wave velocity (cfPWV) and sympathetic BRS during spontaneous breathing. Awake and asleep ABPM-BPs and morning surge were higher in hypertensive than normotensive subjects (all P < 0.001). cfPWV was higher (P = 0.002) and sympathetic BRS was lower (P = 0.096) in hypertensive than normotensive subjects. Hypertensive subjects with morning surge ≥35 mmHg (median value) had higher cfPWV (11.9 ± 0.5 vs. 9.9 ± 0.4 m/s, P = 0.002) and lower sympathetic BRS (supine: -2.71 ± 0.25 vs. -3.73 ± 0.29, P = 0.011; upright: -2.62 ± 0.22 vs. -3.51 ± 0.35 bursts·100 beats(-1)·mmHg(-1), P = 0.052) than those with morning surge <35 mmHg. MSNA indices were similar between groups (all P > 0.05), while upright total peripheral resistance was higher in hypertensive subjects with greater morning surge than those with lesser morning surge (P = 0.050). Morning surge was correlated positively with cfPWV (r = 0.59, P < 0.001) and negatively with sympathetic BRS (r = 0.51, P < 0.001) in hypertensive subjects only. Thus, morning BP surge is associated with arterial stiffness and sympathetic BRS, as well as vasoreactivity during orthostasis in hypertensive seniors.

Chinese herbal medicine qi ju di huang wan for the treatment of essential hypertension: a systematic review of randomized controlled trials

Background. Chinese herbs are potentially effective for hypertension. Qi Ju Di Huang Wan (QJDHW) is a commonly used Chinese herbal medicine as a monotherapy or in combination with other antihypertensive agents for the treatment of essential hypertension (EH). However, there is no critically appraised evidence such as systematic reviews or meta-analyses on the effectiveness and safety of QJDHW for EH. Methods and Findings. CENTRAL, PubMed, CBM, CNKI, VIP, and online clinical trial registry websites were searched for published and unpublished randomized controlled trials (RCTs) of QJDHW for essential hypertension up to January 2013 with no language restrictions. A total of 10 randomized trials involving 1024 patients were included. Meta-analysis showed that QJDHW combined with antihypertensive drugs was more effective in lowering blood pressure and improving TCM syndrome for the treatment of essential hypertension than antihypertensive drugs used alone. No trials reported severe adverse events related to QJDHW. Conclusions. Our review suggests that QJDHW combined with antihypertensive drugs might be an effective treatment for lowering blood pressure and improving symptoms in patients with essential hypertension. However, the finding should be interpreted with caution because of the poor methodological quality of included trials. There is an urgent need for well-designed, long-term studies to assess the effectiveness of QJDHW in the treatment of essential hypertension.

Mobile personal health system for ambulatory blood pressure monitoring

The ARVmobile v1.0 is a multiplatform mobile personal health monitor (PHM) application for ambulatory blood pressure (ABP) monitoring that has the potential to aid in the acquisition and analysis of detailed profile of ABP and heart rate (HR), improve the early detection and intervention of hypertension, and detect potential abnormal BP and HR levels for timely medical feedback. The PHM system consisted of ABP sensor to detect BP and HR signals and smartphone as receiver to collect the transmitted digital data and process them to provide immediate personalized information to the user. Android and Blackberry platforms were developed to detect and alert of potential abnormal values, offer friendly graphical user interface for elderly people, and provide feedback to professional healthcare providers via e-mail. ABP data were obtained from twenty-one healthy individuals (>51 years) to test the utility of the PHM application. The ARVmobile v1.0 was able to reliably receive and process the ABP readings from the volunteers. The preliminary results demonstrate that the ARVmobile 1.0 application could be used to perform a detailed profile of ABP and HR in an ordinary daily life environment, bedsides of estimating potential diagnostic thresholds of abnormal BP variability measured as average real variability.

2013 ambulatory blood pressure monitoring recommendations for the diagnosis of adult hypertension, assessment of cardiovascular and other hypertension-associated risk, and attainment of therapeutic goals

Correlation between systolic (SBP) and diastolic (DBP) blood pressure (BP) level and target organ damage, cardiovascular disease (CVD) risk, and long-term prognosis is much greater for ambulatory BP monitoring (ABPM) than daytime office measurements. The 2013 ABPM guidelines specified herein are based on ABPM patient outcomes studies and constitute a substantial revision of current knowledge. The asleep SBP mean and sleep-time relative SBP decline are the most significant predictors of CVD events, both individually as well as jointly when combined with other ABPM-derived prognostic markers. Thus, they should be preferably used to diagnose hypertension and assess CVD and other associated risks. Progressive decrease by therapeutic intervention of the asleep BP mean is the most significant predictor of CVD event-free interval. The 24-h BP mean is not recommended to diagnose hypertension because it disregards the more valuable clinical information pertaining to the features of the 24-h BP pattern. Persons with the same 24-h BP mean may display radically different 24-h BP patterns, ranging from extreme-dipper to riser types, representative of markedly different risk states. Classification of individuals by comparing office with either the 24-h or awake BP mean as "masked normotensives" (elevated clinic BP but normal ABPM), which should replace the terms of "isolated office" or "white-coat hypertension", and "masked hypertensives" (normal clinic BP but elevated ABPM) is misleading and should be avoided because it disregards the clinical significance of the asleep BP mean. Outcome-based ABPM reference thresholds for men, which in the absence of compelling clinical conditions are 135/85 mmHg for the awake and 120/70 mmHg for the asleep SBP/DBP means, are lower by 10/5 mmHg for SBP/DBP in uncomplicated, low-CVD risk, women and lower by 15/10 mmHg for SBP/DBP in male and female high-risk patients, e.g., with diabetes, chronic kidney disease (CKD), and/or past CVD events. In the adult population, the combined prevalence of masked normotension and masked hypertension is >35%. Moreover, >20% of "normotensive" adults have a non-dipper BP profile and, thus, are at relatively high CVD risk. Clinic BP measurements, even if supplemented with home self-measurements, are unable to quantify 24-h BP patterning and asleep BP level, resulting in potential misclassification of up to 50% of all evaluated adults. ABPM should be viewed as the new gold standard to diagnose true hypertension, accurately assess consequent tissue/organ, maternal/fetal, and CVD risk, and individualize hypertension chronotherapy. ABPM should be a priority for persons likely to have a blunted nighttime BP decline and elevated CVD risk, i.e., those who are elderly and obese, those with secondary or resistant hypertension, and those diagnosed with diabetes, CKD, metabolic syndrome, and sleep disorders.

Resting sympathetic outflow does not predict the morning blood pressure surge in hypertension

OBJECTIVE

The blood pressure (BP) rise on awakening (morning surge) might be a predictor of hypertension-related cardiovascular complications. Previous studies suggest that the autonomic nervous system may contribute to the early morning BP increase. We tested the hypothesis that resting sympathetic outflow [assessed by direct measures of intraneural sympathetic nerve activity (SNA)] may help predict the morning BP surge in hypertension.

METHODS

We measured muscle SNA (MSNA), heart rate (HR) and BP during undisturbed supine rest in 68 newly diagnosed untreated hypertensive patients (53 men and 15 women, age 40 ± 3 years, BMI 27 ± 1 kg/m(2), mean ± SEM). The morning BP surge was defined as the difference between the morning BP and the pre-awake BP.

RESULTS

SBP averaged 143 ± 3 mmHg for daytime and 126 ± 2 mmHg for night-time. Mean HR was 81 ± 2 beats/min for daytime and 69 ± 2 beats/min for night-time. Average MSNA was 32 ± 2 bursts/min., SBP morning surge 19 ± 2 mmHg and HR morning surge 14 ± 2 beats/min. In univariate analysis, MSNA correlated with daytime SBP (r = 0.28, P = 0.02); night-time SBP (r = 0.26, P = 0.03); daytime HR (r = 0.28, P = 0.02); and night-time HR (r = 0.26, P = 0.03). Multivariate analysis, taking into consideration age, BMI and sex, revealed that MSNA was independently related to both daytime (P = 0.006) and night-time HR (P = 0.02), but not to ambulatory SBP. The morning surge of SBP and HR was not related to MSNA (r = 0.01 and r = 0.07, respectively, P = NS).

CONCLUSION

In patients with essential hypertension, MSNA is related to both daytime and night-time HR, but not to the morning BP surge.

Does blood pressure variability modulate cardiovascular risk?

Exactly how hypertension causes end organ damage and vascular events is poorly understood. Yet the concept that underlying "usual" blood pressure (BP) accounts for all BP-related risk of vascular events and for the benefits of BP-lowering drugs has come to underpin clinical guidelines on the diagnosis and treatment of hypertension. This article reviews evidence that variability in BP also predicts risk of stroke and other vascular events independently of mean BP and evidence that drug-class effects on variability in BP explain differences in the effectiveness of BP-lowering drugs in preventing stroke.

Predictive role of the nighttime blood pressure

Numerous studies addressed the predictive value of the nighttime blood pressure (BP) as captured by ambulatory monitoring. However, arbitrary cutoff limits in dichotomized analyses of continuous variables, data dredging across selected subgroups, extrapolation of cross-sectional studies to prospective outcomes, and lack of comprehensive adjustments for confounders make interpretation of the literature difficult. We reviewed prospective studies with total mortality or a composite cardiovascular end point as an outcome in relation to the level and the circadian profile of systolic BP. We analyzed studies in hypertensive patients (n = 23 856) separately from those in individuals randomly recruited from populations (n = 9641). We pooled summary statistics and individual subject data, respectively. In both patients and populations, in analyses in which nighttime BP was additionally adjusted for daytime BP and vice versa, nighttime BP was a stronger predictor than daytime BP. With adjustment for the 24-hour BP, both the night-to-day BP ratio and dipping status remained significant predictors of outcome but added little prognostic value over and beyond the 24-hour BP level. In the absence of conclusive evidence proving that nondipping is a reversible risk factor, the option whether or not to restore the diurnal blood pressure profile to a normal pattern should be left to the clinical judgment of doctors and should be individualized for each patient. Current guidelines on the interpretation of ambulatory BP recording need to be updated.

From pioneering to implementing automated blood pressure measurement in clinical practice: Thomas Pickering's legacy

Thomas G. Pickering spent most of his scientific career in carrying out research on clinical hypertension and blood pressure (BP) measurement. In our review of Pickering's seminal work, we first focused on white-coat hypertension and masked hypertension, two terms that he had introduced. Next, we highlighted the early publications of Pickering on diurnal BP variability and on the clinical application of self-measured BP. Pickering's work inspired many investigators worldwide and constituted a solid basis for further research. Pickering's original ideas led to algorithms for risk stratification involving white-coat hypertension and masked hypertension, diurnal BP variability, and self-measured BP. Recent studies validated Pickering's observations in terms of cardiovascular outcome and bridged the path from concept to application in clinical practice.

Blood pressure variability in relation to outcome in the International Database of Ambulatory blood pressure in relation to Cardiovascular Outcome

Ambulatory blood pressure (BP) monitoring provides information not only on the BP level but also on the diurnal changes in BP. In the present review, we summarized the main findings of the International Database on Ambulatory BP in relation to Cardiovascular Outcome (IDACO) with regard to risk stratification based on BP variability. The predictive accuracy of daytime and nighttime BP and the night-to-day BP ratio depended on the disease outcome under study and treatment status, and differed for fatal outcomes compared with the composite of fatal and nonfatal diseases. An exaggerated morning surge, exceeding the 90th percentile of the population, is an independent risk factor for mortality and cardiovascular and cardiac events. Conversely, a sleep-trough or preawakening morning surge in systolic BP below 20 mm Hg is probably not associated with an increased risk of death or cardiovascular events. BP variability as captured by the average of the daytime and nighttime s.d. weighted for the duration of the daytime and nighttime interval (s.d.(dn)) and the average real variability (ARV(24)) predicted the outcome, but improved the prediction of the composite of all cardiovascular events by only 0.1%. In conclusion, the IDACO observations support the concept that BP variability adds to risk stratification, but above all highlight that 24-h ambulatory BP level remains the main predictor to be considered in clinical practice.

Prognostic Value of the Morning Blood Pressure Surge in 5645 Subjects From 8 Populations

Previous studies on the prognostic significance of the morning blood pressure surge (MS) produced inconsistent results. Using the International Database on Ambulatory Blood Pressure in Relation to Cardiovascular Outcome, we analyzed 5645 subjects (mean age: 53.0 years; 54.0% women) randomly recruited in 8 countries. The sleep-through and the preawakening MS were the differences in the morning blood pressure with the lowest nighttime blood pressure and the preawakening blood pressure, respectively. We computed multivariable-adjusted hazard ratios comparing the risk in ethnic- and sex-specific deciles of the MS relative to the average risk in the whole study population. During follow-up (median: 11.4 years), 785 deaths and 611 fatal and nonfatal cardiovascular events occurred. While accounting for covariables and the night:day ratio of systolic pressure, the hazard ratio of all-cause mortality was 1.32 (95% CI: 1.09 to 1.59; P =0.004) in the top decile of the systolic sleep-through MS (≥37.0 mm Hg). For cardiovascular and noncardiovascular death, these hazard ratios were 1.18 (95% CI: 0.87 to 1.61; P =0.30) and 1.42 (95% CI: 1.11 to 1.80; P =0.005). For all cardiovascular, cardiac, coronary, and cerebrovascular events, the hazard ratios in the top decile of the systolic sleep-through MS were 1.30 (95% CI: 1.06 to 1.60; P =0.01), 1.52 (95% CI: 1.15 to 2.00; P =0.004), 1.45 (95% CI: 1.04 to 2.03; P =0.03), and 0.95 (95% CI: 0.68 to 1.32; P =0.74), respectively. Analysis of the preawakening systolic MS and the diastolic MS generated consistent results. In conclusion, a MS above the 90th percentile significantly and independently predicted cardiovascular outcome and might contribute to risk stratification by ambulatory blood pressure monitoring.

Limitations of the usual blood-pressure hypothesis and importance of variability, instability, and episodic hypertension

Although hypertension is the most prevalent treatable vascular risk factor, how it causes end-organ damage and vascular events is poorly understood. Yet, a widespread belief exists that underlying usual blood pressure can alone account for all blood-pressure-related risk of vascular events and for the benefits of antihypertensive drugs, and this notion has come to underpin all major clinical guidelines on diagnosis and treatment of hypertension. Other potentially informative measures, such as variability in clinic blood pressure or maximum blood pressure reached, have been neglected, and effects of antihypertensive drugs on such measures are largely unknown. Clinical guidelines recommend that episodic hypertension is not treated, and the potential risks of residual variability in blood pressure in treated hypertensive patients have been ignored. This Review discusses shortcomings of the usual blood-pressure hypothesis, provides background to accompanying reports on the importance of blood-pressure variability in prediction of risk of vascular events and in accounting for benefits of antihypertensive drugs, and draws attention to clinical implications and directions for future research.

Long-term reproducibility of ambulatory blood pressure is superior to office blood pressure in the very elderly

While it is known that reproducibility of ambulatory blood pressure (BP) is superior to office BP in middle-aged subjects, little is known older age groups. Hence, we compared the long-term reproducibility of ambulatory and office BP readings in subjects over the age of 75 years. A cohort of 72 subjects 75-90 years of age (mean, 82 years at baseline) had repeat office and ambulatory blood pressures 2 years apart under similar conditions. On the same day, patients underwent office BP measurements by a semi-automated device and then by ambulatory BP monitoring. Awake and sleep periods were divided according to a diary kept by each patient. The agreement between studies was assessed using the standard deviation of the differences (SDD) and Bland-Altman plots. There were minimal mean changes in office, 24-hour, awake and sleep mean BP values between baseline and 2 years later. The SDDs between visits were lower for 24-hour BP compared to the office BP (11.7/5.9 mmHg versus 17.8/9.0 mmHg, p < 0.01). The SDD for 24-hour BP was also lower than the SDDs for the awake and sleep BP (p < 0.05). Nocturnal BPs defined by absolute values were more reproducible than categories of dippers and non-dippers. These data demonstrate that long-term reproducibility of 24-hour BP is superior to office measurements for very elderly subjects. In a clinical trial involving this age group, far fewer subjects would be required if 24-hour BP was the primary efficacy endpoint rather than the office BP.

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

OBJECTIVES

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.