Blood pressure and heart rate variabilities in normotensive and hypertensive human beings

Is the heart rate dipping pattern associated with sleep quality during an ambulatory blood pressure monitoring? A cross-sectional study

OBJECTIVE

The aim of this study was to characterize individuals with nondipping heart rate (HR) and to assess the association between that pattern and sleep quality during the night of an ambulatory blood pressure monitoring (ABPM).

METHODS

Individuals who attended our Unit to perform an ABPM, from February 2022 to May 2024, were asked about clinical and epidemiological antecedents and responded two validated surveys, about sleep quality during the night of the ABPM and in the prior 30 days. Then, they were categorized according to the presence of a dipping in nocturnal HR (defined as a decline in average HR at night equal or higher than 10% compared with daytime values) as HR dippers or HR nondippers (drop in mean nighttime HR lower than 10% of diurnal mean) in order to compare the mentioned variables.

RESULTS

One thousand two hundred and nine individuals were included. They were predominantly female (61.8%), middle-aged (median 50 years, IQR 36-60), overweight (median BMI 29, IQR 25.3-33.5) and had median ABPM estimates within normal ranges. In individuals without beta-blockers ( n  = 1107), HR nondippers had an adverse cardiovascular disease (CVD) risk profile, and no differences were found between HR dippers and HR nondippers concerning perceived good rest during the ABPM night (63.5 vs. 59.7%, P  = 0.211) and usual sleep quality. The sensitivity analysis including beta-blockers' users ( n  = 102) was consistent.

CONCLUSION

A blunted dipping in mean nighttime HR identifies individuals with a high CVD risk profile and is not associated with bad sleep quality during the night of an ABPM.

Elevated blood pressure variability is associated with an increased risk of negative health outcomes in adults aged 65 and above-a systematic review and meta-analysis

BACKGROUND

The clinical relevance of blood pressure variability (BPV) is still unknown, despite increasing evidence associating BPV to negative health outcomes (NHOs). There is currently no gold standard to define high BPV and normal reference values for BPV are lacking.

AIM

The primary aim was to examine whether high BPV can predict NHO in adults aged ≥65. The predictive value of BPV was compared to mean BP (mBP) when both parameters were available.

METHODS

PubMed and Web of Science were systematically screened; 49 articles (12 retrospective, 18 prospective and 19 cross-sectional studies) were included and evaluated for methodological quality. Meta-analyses were conducted to examine the association of BPV (and mBP when available) with NHO.

RESULTS

Systolic BPV and systolic mBP seem to indicate at least comparable odds for cardiovascular disease (BPV: odds ratio (OR) = 1.33 (95% CI: 1.19-1.48, P < .00001) vs mBP: OR = 1.06 (95% CI: 1.03-1.09, P = .0002)) and cerebral deterioration (BPV: OR = 1.28 (95% CI: 1.17-1.41, P < .00001) vs mBP: OR = 1.06 (95% CI: 1.04-1.09, P < .00001)). Increased diastolic BPV was associated with higher odds of cerebral deterioration (OR = 1.18 (95% CI: 1.04-1.35), P = .01).

CONCLUSION

High systolic BPV and high systolic mBP are associated with 33% and 6% higher odds of cardiovascular disease in adults aged ≥65, respectively. High BPV is also related to an 18%-28% and 11% increased odds of cerebral deterioration and poor stroke recovery. An overview of cut-off values is provided for the most often reported BPV parameters in literature, which can be used as a guideline to identify elevated BPV in clinical practice.

Employing Deep Reinforcement Learning to Maximize Lower Limb Blood Flow Using Intermittent Pneumatic Compression

Intermittent pneumatic compression (IPC) systems apply external pressure to the lower limbs and enhance peripheral blood flow. We previously introduced a cardiac-gated compression system that enhanced arterial blood velocity (BV) in the lower limb compared to fixed compression timing (CT) for seated and standing subjects. However, these pilot studies found that the CT that maximized BV was not constant across individuals and could change over time. Current CT modelling methods for IPC are limited to predictions for a single day and one heartbeat ahead. However, IPC therapy for may span weeks or longer, the BV response to compression can vary with physiological state, and the best CT for eliciting the desired physiological outcome may change, even for the same individual. We propose that a deep reinforcement learning (DRL) algorithm can learn and adaptively modify CT to achieve a selected outcome using IPC. Herein, we target maximizing lower limb arterial BV as the desired outcome and build participant-specific simulated lower limb environments for 6 participants. We show that DRL can adaptively learn the CT for IPC that maximized arterial BV. Compared to previous work, the DRL agent achieves 98% ± 2 of the resultant blood flow and is faster at maximizing BV; the DRL agent can learn an "optimal" policy in 15 minutes ± 2 on average and can adapt on the fly. Given a desired objective, we posit that the proposed DRL agent can be implemented in IPC systems to rapidly learn the (potentially time-varying) "optimal" CT with a human-in-the-loop.

Blood pressure measurement and adverse pregnancy outcomes: A cohort study testing blood pressure variability and alternatives to 140/90 mmHg

OBJECTIVE

To examine the association with adverse pregnancy outcomes of: (1) American College of Cardiology/American Heart Association blood pressure (BP) thresholds, and (2) visit-to-visit BP variability (BPV), adjusted for BP level.

DESIGN

An observational study.

SETTING

Analysis of data from the population-based UK Southampton Women's Survey (SWS).

POPULATION OR SAMPLE

3003 SWS participants.

METHODS

Generalised estimating equations were used to estimate crude and adjusted relative risks (RRs) of adverse pregnancy outcomes by BP thresholds, and by BPV (as standard deviation [SD], average real variability [ARV] and variability independent of the mean [VIM]). Likelihood ratios (LRs) were calculated to evaluate diagnostic test properties, for BP at or above a threshold, compared with those below.

MAIN OUTCOME MEASURES

Gestational hypertension, severe hypertension, pre-eclampsia, preterm birth (PTB), small-for-gestational-age (SGA) infants, neonatal intensive care unit (NICU) admission.

RESULTS

A median of 11 BP measurements were included per participant. For BP at ≥20 weeks' gestation, higher BP was associated with more adverse pregnancy outcomes; however, only BP <140/90 mmHg was a good rule-out test (negative LR <0.20) for pre-eclampsia and BP ≥140/90 mmHg a good rule-in test (positive LR >8.00) for the condition. BP ≥160/110 mmHg could rule-in PTB, SGA infants and NICU admission (positive LR >5.0). Higher BPV (by SD, ARV, or VIM) was associated with gestational hypertension, severe hypertension, pre-eclampsia, PTB, SGA and NICU admission (adjusted RRs 1.05-1.39).

CONCLUSIONS

While our findings do not support lowering the BP threshold for pregnancy hypertension, they suggest BPV could be useful to identify elevated risk of adverse outcomes.

Effects of long-term indoor air purification intervention on cardiovascular health in elderly: a parallel, double-blinded randomized controlled trial in Hong Kong

Ambient fine particulate matter (PM2.5) is a leading environmental risk factor globally, and over half of the associated disease burden are caused by cardiovascular disease. Numerous randomized controlled trials (RCT) have investigated the short-term cardiovascular benefits of indoor air purifiers (IAPs), but major knowledge gaps remain on their longer-term benefits. In this 1-year, randomized, double-blinded, parallel controlled trial of 47 elderly (ntrue-purification = 24; nsham-purification = 23) aged ≥70 years, true-purification reduced household PM2.5 levels by 28% and maintained lower exposure throughout the year compared to the sham-purification group. After 12 months of intervention, a significant reduction of diastolic blood pressure was found in the true-purification versus sham-purification group (-4.62 [95% CI: -7.28, -1.96] mmHg) compared to baseline measurement prior to the intervention, whereas systolic blood pressure showed directionally consistent but statistically non-significant effect (-2.49 [95% CI: -9.25, 4.28] mmHg). Qualitatively similar patterns of associations were observed for pulse pressure (-2.30 [95% CI: -6.57, 1.96] mmHg) and carotid intima-media thickness (-10.0% [95% CI: -24.8%, 4.7%]), but these were not statistically significant. Overall, we found suggestive evidence of cardiovascular benefits of long-term IAPs use, particularly on diastolic blood pressure. Evidence on other longer-term cardiovascular traits is less clear. Further trials with larger sample sizes and long-term follow-up are needed across diverse populations to evaluate the cardiovascular benefits of IAPs.

Effect of odor stimulations on physical activity: A systematic review

Fewer and fewer people are reaching physical activity recommendations. Therefore, it seems important to make the practice of physical activity more enjoyable to increase the participation rate. Several environmental factors have been studied to see their impact on sports practice, and some studies investigated the effect of odors. This systematic review aims to provide a thorough view of the literature on the effect of different odors on physical activity. The search strategy consisted of using index terms and keywords in MEDLINE, EMBASE, EBM Reviews - Cochrane Central Register of Controlled Trials, CINAHL, SPORTDiscus, and Web of Science search engine. Data from 19 studies that included 458 participants revealed that the odors had different results on strength, cardiovascular, precision, and postural balance tasks depending on the odors' exposition. Among results, an important distinction was made between pleasant and unpleasant odors. Therefore, pleasant odors had better results on physical activity by improving participants' feeling. Even though this review clarified evidence about the effect of odors on physical activity, better methodological consistency is needed across studies such as the odor administration method to produce more meaningful results.

Comparison of Ambulatory and Home Blood Pressure Variability for Cardiovascular Prognosis and Biomarkers

BACKGROUND

Although blood pressure variability (BPV) is reported to be associated with cardiovascular prognoses, it has not been established whether ambulatory BPV (ABPV; ie, short-term 24-hour BPV) or home BPV (HBPV; day-to-day BPV) is a superior clinical marker.

METHODS

We analyzed the associations of ABPV and HBPV with cardiovascular prognoses and biomarkers in 1314 hypertensive outpatients who underwent both home and ambulatory BP measurements in the J-HOP study (Japan Morning-Surge Home Blood Pressure). BPV was evaluated by the SD, coefficient of variation, and average real variability of the patients' 24-hour ambulatory and home systolic BP values.

RESULTS

During the median 7.0-year follow-up, 109 cardiovascular events occurred. All SD, coefficient of variation, and average real variability values of the HBPV were significantly associated with cardiovascular risk even after adjusting by average 24-hour ambulatory systolic BP and each ABPV value: 1 SD of hazard ratio (95% CI) for the SD, 1.36 (1.14-1.63); coefficient of variation, 1.38 (1.16-1.66); and average real variability 1.29 (1.10-1.51) of HBPV. The ABPV parameters did not exhibit comparable relationships. The cardiovascular risk spline curves showed a trend toward increased risks with increasing HBPV parameters. There were no differences between ABPV and HBPV in the relationships with B-type natriuretic peptide and the urine albumin-creatine ratio.

CONCLUSIONS

In this comparative analysis of ambulatory and home BP monitoring values in individuals with hypertension, ABPV was not significantly associated with cardiovascular prognosis adjusted by average BP level, and HBPV was suggested to have modest superiority in predicting cardiovascular prognosis compared with ABPV.

Respiratory Event-Induced Blood Pressure Oscillations Vary by Sleep Stage in Sleep Apnea Patients

Obstructive sleep apnea (OSA) pathologically stresses the cardiovascular system. Apneic events cause significant oscillatory surges in nocturnal blood pressure (BP). Trajectories of these surges vary widely. This variability challenges the quantification, characterization, and mathematical modeling of BP surge dynamics. We present a method of aggregating trajectories of apnea-induced BP surges using a sample-by-sample averaging of continuously recorded BP. We applied the method to recordings of overnight BP (average total sleep time: 4.77 ± 1.64 h) for 10 OSA patients (mean AHI: 63.5 events/h; range: 18.3-105.4). We studied surges in blood pressure due to obstructive respiratory events separated from other such events by at least 30 s (274 total events). These events increased systolic (SBP) and diastolic (DBP) BP by 19 ± 7.1 mmHg (14.8%) and 11 ± 5.6 mmHg (15.5%), respectively, relative to mean values during wakefulness. Further, aggregated SBP and DBP peaks occurred on average 9 s and 9.5 s after apnea events, respectively. Interestingly, the amplitude of the SBP and DBP peaks varied across sleep stages, with mean peak ranging from 128.8 ± 12.4 to 166.1 ± 15.5 mmHg for SBP and from 63.1 ± 8.2 to 84.2 ± 9.4 mmHg for DBP. The aggregation method provides a high level of granularity in quantifying BP oscillations from OSA events and may be useful in modeling autonomic nervous system responses to OSA-induced stresses.

The usability of daytime and night-time heart rate dynamics as digital biomarkers of depression severity

BACKGROUND

Alterations in heart rate (HR) may provide new information about physiological signatures of depression severity. This 2-year study in individuals with a history of recurrent major depressive disorder (MDD) explored the intra-individual variations in HR parameters and their relationship with depression severity.

METHODS

Data from 510 participants (Number of observations of the HR parameters = 6666) were collected from three centres in the Netherlands, Spain, and the UK, as a part of the remote assessment of disease and relapse-MDD study. We analysed the relationship between depression severity, assessed every 2 weeks with the Patient Health Questionnaire-8, with HR parameters in the week before the assessment, such as HR features during all day, resting periods during the day and at night, and activity periods during the day evaluated with a wrist-worn Fitbit device. Linear mixed models were used with random intercepts for participants and countries. Covariates included in the models were age, sex, BMI, smoking and alcohol consumption, antidepressant use and co-morbidities with other medical health conditions.

RESULTS

Decreases in HR variation during resting periods during the day were related with an increased severity of depression both in univariate and multivariate analyses. Mean HR during resting at night was higher in participants with more severe depressive symptoms.

CONCLUSIONS

Our findings demonstrate that alterations in resting HR during all day and night are associated with depression severity. These findings may provide an early warning of worsening depression symptoms which could allow clinicians to take responsive treatment measures promptly.

Interpretation of Ambulatory Blood Pressure Monitoring for Risk Stratification in Hypertensive Patients: The 'Ambulatory Does Prediction Valid (ADPV)' Approach

Several outcome-based prospective investigations have provided solid data which support the prognostic value of 24 h ambulatory blood pressure over and beyond cardiovascular traditional risk factors. Average 24 h, daytime, and nighttime blood pressures are the principal components of the ambulatory blood pressure profile that have improved cardiovascular risk stratification beyond traditional risk factors. Furthermore, several additional ambulatory blood pressure measures have been investigated. The correct interpretation in clinical practice of ambulatory blood pressure monitoring needs a standardization of methods. Several algorithms for its clinical use have been proposed. Implementation of the results of ambulatory blood pressure monitoring in the management of individual subjects with the aim of improving risk stratification is challenging. We suggest that clinicians should focus attention on ambulatory blood pressure components which have been proven to act as the main independent predictors of outcome (average 24 h, daytime, and nighttime blood pressure, pulse pressure, dipping status, BP variability).

Blood Pressure Variability and the Progression of Chronic Kidney Disease: a Systematic Review and Meta-Analysis

BACKGROUND

Blood pressure variability (BPV) is a risk factor for poor prognosis including cardiovascular events, chronic kidney disease, and mortality, independent of elevated BP.

METHODS

We searched PubMed/Medline, EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL) from inception to November 23, 2022. Cohort studies reporting the association between BPV and chronic kidney disease (CKD) progression were selected. Hazard ratios were pooled using a random-effects model. Meta-regression, subgroup analyses, and sensitivity analyses were conducted.

RESULTS

A total of 23 studies were included in this systematic review and meta-analysis. Increased BPV was associated with progression of CKD (HR: 1.21, 95% CI: 1.09-1.33) and incidence of ESRD (HR: 1.08, 95% CI: 1.08-1.30). Among the different BPV metrics, high variation independent of mean (VIM), coefficient of variation (CV), standard deviation (SD), and average real variability (ARV) were indicated as predictors of CKD progression.

DISCUSSION

Increased BPV was associated with CKD progression.

Blood pressure variability: methodological aspects, clinical relevance and practical indications for management - a European Society of Hypertension position paper ∗

Blood pressure is not a static parameter, but rather undergoes continuous fluctuations over time, as a result of the interaction between environmental and behavioural factors on one side and intrinsic cardiovascular regulatory mechanisms on the other side. Increased blood pressure variability (BPV) may indicate an impaired cardiovascular regulation and may represent a cardiovascular risk factor itself, having been associated with increased all-cause and cardiovascular mortality, stroke, coronary artery disease, heart failure, end-stage renal disease, and dementia incidence. Nonetheless, BPV was considered only a research issue in previous hypertension management guidelines, because the available evidence on its clinical relevance presents several gaps and is based on heterogeneous studies with limited standardization of methods for BPV assessment. The aim of this position paper, with contributions from members of the European Society of Hypertension Working Group on Blood Pressure Monitoring and Cardiovascular Variability and from a number of international experts, is to summarize the available evidence in the field of BPV assessment methodology and clinical applications and to provide practical indications on how to measure and interpret BPV in research and clinical settings based on currently available data. Pending issues and clinical and methodological recommendations supported by available evidence are also reported. The information provided by this paper should contribute to a better standardization of future studies on BPV, but should also provide clinicians with some indications on how BPV can be managed based on currently available data.

Age-related patterns of ambulatory blood pressure in a large cohort of individuals referred to Italian community pharmacies: results from the templar project

OBJECTIVES

Ambulatory blood pressure monitoring (ABPM) provides extensive information on several BP parameters other than the average BP during daily life. Through this analysis of the TEMPLAR study, we sought to understand better the features of age-related changes in ABP patterns and phenotypes.

METHODS

ABPMs were obtained in 53 350 individuals visiting 866 Italian community pharmacies (age 3-101 years, 54.3% female individuals). ABPM patterns were assessed across 10-year age categories.

RESULTS

SBP steadily increased with age. DBP increased from the youth to the middle adulthood and then declined. Daytime BP was higher than night-time BP, but the difference narrowed with aging, reducing the prevalence of dippers. An enhanced SBP morning surge and increased prevalence of abnormal morning rise were observed with aging. SBP and DBP variabilities increased with age with a typical U or J shape, more evident in the case of DBP. The proportion of participants with ambulatory hypertension increased with age. However, an elevated daytime BP was more common in younger individuals and elevated night-time hypertension in older individuals. The prevalence of white-coat hypertension remained stable or slightly declined through the age groups, whereas that of masked hypertension steadily increased.

CONCLUSION

Our results confirm that ABP patterns interplay and change in a complex way with age. Such changes, particularly the age-related increase in BP variability and prevalence of nocturnal hypertension, nondipping, enhanced morning rise, and masked hypertension, may increase the risk of cardiovascular events and must be carefully considered by the physician when managing BP in the elderly.

Effects of One Night of Forced Wakefulness on Morning Resting Blood Pressure in Humans: The Role of Biological Sex and Weight Status

Permanent night shift work is associated with adverse health effects, including elevated blood pressure (BP) and hypertension. Here, we examined the BP response to one night of forced wakefulness in a sitting position in a cohort without night shift work experience. According to a counterbalanced crossover design, 47 young adults with either obesity (N = 22; 10 women) or normal weight (N = 25; 11 women) participated in one night of sleep and one night of forced wakefulness under in-laboratory conditions. Resting ankle and brachial arterial BP were assessed in the morning, i.e., the time of the day when adverse cardiovascular events peak. After forced wakefulness, diastolic and mean arterial BP were ~4 mmHg higher at the ankle site and ~3 mmHg higher at the brachial site than after regular sleep (p < 0.05). The increase in BP following overnight forced wakefulness was more pronounced among men vs. women and more significant for diastolic BP at both sites among participants with normal weight vs. those with obesity. If confirmed in larger cohorts, including 24 h BP monitoring, people with occupations involving night shifts might benefit from regular BP monitoring. Particular attention should be paid to possible sex- and weight-specific effects of night shift work on BP.

The potential therapeutic benefits of low frequency haemodynamic oscillations

Haemodynamic oscillations occurring at frequencies below the rate of respiration have been observed experimentally for more than a century. Much of the research regarding these oscillations, observed in arterial pressure and blood flow, has focused on mechanisms of generation and methods of quantification. However, examination of the physiological role of these oscillations has been limited. Multiple studies have demonstrated that oscillations in arterial pressure and blood flow are associated with the protection in tissue oxygenation or functional capillary density during conditions of reduced tissue perfusion. There is also evidence that oscillatory blood flow can improve clearance of interstitial fluid, with a growing number of studies demonstrating a role for oscillatory blood flow to aid in clearance of debris from the brain. The therapeutic potential of these haemodynamic oscillations is an important new area of research which may have beneficial impact in treating conditions such as stroke, cardiac arrest, blood loss injuries, sepsis, or even Alzheimer's disease and vascular dementia.

Bedtime dosing of antihypertensive medications: systematic review and consensus statement: International Society of Hypertension position paper endorsed by World Hypertension League and European Society of Hypertension

Antihypertensive drug therapy is one of the most efficient medical interventions for preventing disability and death globally. Most of the evidence supporting its benefits has been derived from outcome trials with morning dosing of medications. Accumulating evidence suggests an adverse prognosis associated with night-time hypertension, nondipping blood pressure (BP) profile and morning BP surge, with increased incidence of cardiovascular events during the first few morning hours. These observations provide justification for complete 24-h BP control as being the primary goal of antihypertensive treatment. Bedtime administration of antihypertensive drugs has also been proposed as a potentially more effective treatment strategy than morning administration. This Position Paper by the International Society of Hypertension reviewed the published evidence on the clinical relevance of the diurnal variation in BP and the timing of antihypertensive drug treatment, aiming to provide consensus recommendations for clinical practice. Eight published outcome hypertension studies involved bedtime dosing of antihypertensive drugs, and all had major methodological and/or other flaws and a high risk of bias in testing the impact of bedtime compared to morning treatment. Three ongoing, well designed, prospective, randomized controlled outcome trials are expected to provide high-quality data on the efficacy and safety of evening or bedtime versus morning drug dosing. Until that information is available, preferred use of bedtime drug dosing of antihypertensive drugs should not be routinely recommended in clinical practice. Complete 24-h control of BP should be targeted using readily available, long-acting antihypertensive medications as monotherapy or combinations administered in a single morning dose.

Impact of COVID-19 on Ambulatory Blood Pressure in Young Adults: A Cross-sectional Analysis Investigating Time Since Diagnosis

Previous studies have reported detrimental effects of COVID-19 on the peripheral vasculature. However, reports on blood pressure (BP) are inconsistent, and measurements are made only in the laboratory setting. To date, no studies have measured ambulatory BP. In addition, in previous studies, time since COVID-19 diagnosis among participants varied across a wide range, potentially contributing to the inconsistent BP results. Thus, we aimed to perform a comprehensive assessment of BP and BP variability using ambulatory and laboratory (brachial and central) measurements in young adults who had COVID-19. We hypothesized that ambulatory BP would be elevated post-COVID-19 and that measures of BP would be inversely related with time since diagnosis. Twenty-eight young adults who had COVID-19 [11 ± 6 (range 3–22) wk since diagnosis] and 10 controls were studied. Ambulatory daytime, nighttime, and 24-h systolic BP, diastolic BP, and mean BP were not different between the control and COVID groups (e.g., daytime systolic BP: control, 122 ± 12 mmHg; COVID, 122 ± 10 mmHg; P = 0.937). Similar results were observed for laboratory BPs (all P > 0.05). However, ambulatory daytime, nighttime, and 24-h BPs as well as laboratory brachial BPs were inversely correlated with time since COVID-19 diagnosis (e.g., daytime systolic BP: r = −0.444; P = 0.044, nighttime systolic BP: r = −0.518; P = 0.016). Ambulatory and laboratory-measured BP variability were not different between groups nor correlated with time since diagnosis. Collectively, these data suggest that adverse effects of COVID-19 on BP in young adults are minimal and likely transient.

NEW & NOTEWORTHY We report for the first time that ambulatory daytime, nighttime, and 24-h blood pressure (BP), as well as laboratory BP, were not different between control and COVID participants. However, a significant inverse relationship with time since COVID-19 diagnosis was found (i.e., greater BP with more recent infection). Ambulatory and laboratory BP variability were unaffected and not related with diagnosis time. These findings suggest that COVID-19 may exert only short-lasting effects on BP in young adults.

Beyond the Baroreflex: A New Measure of Autonomic Regulation Based on the Time-Frequency Assessment of Variability, Phase Coherence and Couplings

For decades the role of autonomic regulation and the baroreflex in the generation of the respiratory sinus arrhythmia (RSA) - modulation of heart rate by the frequency of breathing - has been under dispute. We hypothesized that by using autonomic blockers we can reveal which oscillations and their interactions are suppressed, elucidating their involvement in RSA as well as in cardiovascular regulation more generally. R-R intervals, end tidal CO2, finger arterial pressure, and muscle sympathetic nerve activity (MSNA) were measured simultaneously in 7 subjects during saline, atropine and propranolol infusion. The measurements were repeated during spontaneous and fixed-frequency breathing, and apnea. The power spectra, phase coherence and couplings were calculated to characterise the variability and interactions within the cardiovascular system. Atropine reduced R-R interval variability (p < 0.05) in all three breathing conditions, reduced MSNA power during apnea and removed much of the significant coherence and couplings. Propranolol had smaller effect on the power of oscillations and did not change the number of significant interactions. Most notably, atropine reduced R-R interval power in the 0.145-0.6 Hz interval during apnea, which supports the hypothesis that the RSA is modulated by a mechanism other than the baroreflex. Atropine also reduced or made negative the phase shift between the systolic and diastolic pressure, indicating the cessation of baroreflex-dependent blood pressure variability. This result suggests that coherent respiratory oscillations in the blood pressure can be used for the non-invasive assessment of autonomic regulation.

Twenty-four-hour blood pressure and heart rate variability are reduced in patients on left ventricular assist device support

BACKGROUND

Limited data exist on the circadian blood pressure (BP) and heart rate (HR) variations that occur in heart failure (HF) patients on left ventricular assist device (LVAD) support.

METHODS

We prospectively recorded clinic and 24-hour ambulatory BP and HR data in patients on HeartMate II LVAD support. Results were compared to HF patients with ejection fraction ≤30% and controls with no history of cardiovascular disease. Physiologic nocturnal BP and HR dipping was defined as a ≥10% decline compared to daytime values.

RESULT

Twenty-nine LVAD patients (age 59 ± 15 years, 76% male, 38% ischemic etiology), 25 HF patients (age 64 ± 13 years, 84% male, 32% ischemic etiology) and 26 controls (age 56 ± 9 years, 62% male) were studied. Normal nocturnal BP dipping was less frequent in LVAD patients (10%) than in HF patients (28%) and controls (62%) and reversed BP dipping (BP increase at night) was more common in LVAD patients (24%), compared to HF (16%) and controls (8%), (p < 0.001, for all comparisons). Physiologic HR reduction was less frequent in LVAD patients (14%), compared to HF (16%) and controls (59%) (p < 0.001, for all comparisons). Among LVAD patients, 36% exhibited sustained hypertension over the 24-hours and 25% had white-coat hypertension.

CONCLUSIONS

Treatment of advanced HF with an LVAD does not restore physiologic circadian variability of BP and HR; additionally, BP was not adequately controlled in more than a third of LVAD patients, and a quarter of them exhibited white-coat hypertension. Future studies are warranted to confirm these findings and investigate prognostic and management implications in this population.

The Effect of Blood Pressure Variability on Coronary Atherosclerosis Plaques

Hypertension is one of the most important risk factors for coronary heart disease (CHD). The regulation of blood pressure plays a significant role in the development and prognosis of CHD. Blood pressure variability (BPV) refers to the degree of fluctuation of blood pressure over a period of time and is an important indicator of blood pressure stability. Blood pressure fluctuations are complex physiological phenomena, being affected by physiological and pharmacological effects and regulated by behavioral, environmental, hydrodynamic, and neural factors. According to the different time periods for measuring BPV, it can be divided into very short-term, short-term, mid-term, and long-term. Multiple cardiovascular disease animal models and clinical experiments have consistently indicated that abnormal BPV is closely related to coronary events and is a risk factor for CHD independently of average blood pressure. Thrombosis secondary to plaque rupture (PR) or plaque erosion can cause varying blood flow impairment, which is the main pathological basis of CHD. Plaque morphology and composition can influence the clinical outcome, treatment, and prognosis of patients with CHD. Research has shown that PR is more easily induced by hypertension. After adjusting for the traditional factors associated with plaque development, in recent years, some new discoveries have been made on the influence of abnormal BPV on the morphology and composition of coronary plaques and related mechanisms, including inflammation and hemodynamics. This article reviews the impact of BPV on coronary plaques and their related mechanisms, with a view to prevent the occurrence and development of CHD by controlling BPV and to provide new prevention and treatment strategies for the clinical treatment of abnormal blood pressure.

The Effects of Acute Exposure to Prolonged Sitting, with and Without Interruption, on Peripheral Blood Pressure Among Adults: A Systematic Review and Meta-Analysis

BACKGROUND

Previous reviews have shown that exposure to acute prolonged sitting can have detrimental effects on several cardiovascular and cardiometabolic health markers. However, to date, there has been no synthesis of peripheral blood pressure data (including systolic blood pressure, diastolic blood pressure and mean arterial pressure), an important and translatable marker of cardiovascular health. Similarly, no previous study has consolidated the effects of sitting interruptions on peripheral blood pressure.

OBJECTIVES

We aimed to (1) assess the effect of exposure to acute prolonged sitting on peripheral blood pressure and (2) determine the efficacy of sitting interruption strategies as a means of offsetting any negative effects. Subgroup analyses by age and interruption modality were performed to explore heterogeneity.

DATA SOURCES

Electronic databases (PubMed, Web of Science and, SPORTDiscus) were searched from inception to March 2021. Reference lists of eligible studies and relevant reviews were also screened.

STUDY SELECTION

Inclusion criteria for objective (1) were: (i) peripheral blood pressure was assessed non-invasively in the upper limb pre-sitting and post-sitting; (ii) studies were either randomised controlled, randomised crossover or quasi-experimental pre-test vs post-test trials; (iii) the sitting period was ≥ 1 h; (iv) pre-sitting and post-sitting measures were performed in the same posture; and (v) participants were adults (aged ≥ 18 years), free of autonomic or neuromuscular dysfunction. Additional criteria for objective (2) were: (i) the interruption strategy was during the sitting period; (ii) there was an uninterrupted sitting control condition; and (iii) the interruption strategy must have involved participants actively moving their upper or lower limbs.

APPRAISAL AND SYNTHESIS METHODS

In total, 9763 articles were identified, of which 33 met inclusion criteria for objective (1). Of those articles, 22 met inclusion criteria for objective (2). Weighted mean difference (WMD), 95% confidence intervals (95% CI), and standardised mean difference (SMD) were calculated for all trials using inverse variance heterogeneity meta-analysis modelling. Standardised mean difference was used to determine the magnitude of effect, where < 0.2, 0.2, 0.5 and 0.8 were defined as trivial, small, moderate and large, respectively.

RESULTS

(1) Prolonged uninterrupted sitting resulted in trivial and small significant increases in systolic blood pressure (WMD = 3.2 mmHg, 95% CI 0.6 to 5.8, SMD = 0.14) and mean arterial pressure (WMD = 3.3 mmHg, 95% CI 2.2 to 4.4, SMD = 0.37), respectively, and a non-significant trivial increase in diastolic blood pressure. Subgroup analyses indicated that the increases in systolic blood pressure and mean arterial pressure were more pronounced in younger age groups. (2) Interrupting bouts of prolonged sitting resulted in significantly lower systolic blood pressure (WMD =  - 4.4 mmHg, 95% CI - 7.4 to - 1.5, SMD = 0.26) and diastolic blood pressure (WMD =  - 2.4 mmHg, 95% CI - 4.5 to - 0.3, SMD = 0.19) compared with control conditions, particularly when using aerobic interruption strategies.

CONCLUSIONS

Exposure to acute prolonged uninterrupted sitting results in significant increases in systolic blood pressure and mean arterial pressure, particularly in younger age groups. Regularly interrupting bouts of prolonged sitting, particularly with aerobic interruption strategies may reduce negative effects.

Prediction of arterial blood pressure waveforms from photoplethysmogram signals via fully convolutional neural networks

Cardiovascular disease (CVD) is one of the most serious diseases threatening human health. Arterial blood pressure (ABP) waveforms, containing vivid cardiovascular information, are of great significance for the diagnosis and the prevention of CVD. This paper proposes a deep learning model, named ABP-Net, to transform photoplethysmogram (PPG) signals into ABP waveforms that contain vital physiological information related to cardiovascular systems. In order to guarantee the quality of the predicted ABP waveforms, the structure of the network, the input signals and the loss functions are carefully designed. Specifically, a Wave-U-Net, one kind of fully convolutional neural networks (CNN), is taken as the core architecture of the ABP-Net. Besides the original PPG signals, its first derivative and second derivative signals are all utilized as the inputs of the ABP-Net. Additionally, the maximal absolute loss, accompany with the mean squared error loss is employed to ensure the match of the predicted ABP waveform with the reference one. The performance of the proposed ABP network is tested on the public MIMIC II database both in subject-dependent and subject-independent manners. Both results verify the superior performance of the proposed model over those existing methods accordingly. The mean absolute error (MAE) and the root-mean-square error (RMSE) between the predicted waveforms via the ABP-Net and the reference ones are 3.20 mmHg and 4.38 mmHg during the subject-dependent experiments while those are 5.57 mmHg and 7.15 mmHg during the subject-independent experiments. Benefiting from the predicted high-quality ABP waveforms, more ABP related physiological parameters can be better obtained, which effectively expands the application scope of PPG devices.

Influence of smoking and other cardiovascular risk factors on heart rate circadian rhythm in normotensive and hypertensive subjects

Circadian heart rate (HR) is influenced by hypertension and other cardiovascular risk factors particularly smoking, obesity and dyslipidemia. Until now, to evaluate the HR changes due to presence of these risk factors, a single HR office measure or a mean evaluated on day time or night time or 24h was used. However, since HR shows a circadian behavior, a single value represents only a rough approximation of this behavior. In this study, we analyzed the influence of smoking, obesity and dyslipidemia on the circadian rhythm in normotensive and hypertensive subject groups presenting only one of these risk factors. The 24h HR recordings of 170 normotensive (83 without risk factors, 20 smokers, 44 with dyslipidemia, 23 obese) and 353 hypertensive (169 without risk factors, 32 smokers, 99 with dyslipidemia, 53 obese) subjects were acquired using a Holter Blood Pressure Monitor. Results highlighted a specific circadian behavior with three characteristic periods presenting different HR means and rates of HR change in the eight subject groups. The slopes could be used both to estimate the morning HR surge associated with acute cardiovascular effects in the awakening and to evaluate the decline during the night. Moreover, we suggest to use three HR mean values (one for each identified period of the day) rather than two HR values to better describe the circadian HR behavior. Furthermore, smoking increased and dyslipidemia decreased mean HR values from 10:00 to 04:00, both in normotensive and hypertensive subjects in comparison with subjects without risk factors. In this time interval, hypertensive obese subjects showed higher values while normotensive ones presented quite similar values than subjects without risk factors. During the awakening (05:00-10:00) the slopes were similar among all groups with no significant difference among the mean HR values.

Assessment of psychiatric comorbidities and serotonergic or noradrenergic medication use on blood pressure using 24-hour ambulatory blood pressure monitoring

In this study, the authors aimed to assess both nighttime and daytime blood pressure (BP) variability using 24-hour ambulatory BP monitoring (ABPM) in persons with and without psychiatric conditions and with or without selective serotonin reuptake inhibitors (SSRIs) or serotonin-norepinephrine reuptake inhibitors (SNRIs) treatment. In this retrospective study, patients who underwent psychiatric evaluation and ABPM within 6 months of each other between January 1, 2012 and December 31, 2017 were identified using billing data. Participants were divided into three groups-participants with no psychiatric diagnosis and no psychiatric medicine (-Diagnosis/-Medication), those with psychiatric diagnosis and on SSRIs/SNRIs (+Diagnosis/+Medication), and psychiatric diagnosis but no psychiatric medications (+Diagnosis/-Medication). Day and nighttime systolic and diastolic BPs were compared between groups controlling for relevant variables using multivariable linear regression models. A total of 475 participants met inclusion criteria including 135 in the -Diagnosis/-Medication group, 232 in the +Diagnosis/+Medication group, and 108 in the +Diagnosis/-Medication group. In adjusted multivariable analysis, the +Diagnosis/+Medication group had higher nighttime systolic BP (median 120 vs 110 mm (Hg); p = .01) and nighttime diastolic BP (median 68 vs 63 mm (Hg); p = .006) as compared to -Diagnosis/-Medication. No statistically significant differences in BPs between the -Diagnosis/-Medication and +Diagnosis/-Medication groups were observed, after adjustment. Use of SSRIs/SNRIs was associated with significantly higher nocturnal systolic and diastolic BP among patients with psychiatric diagnosis using SSRIs/SNRIs but not associated with psychiatric diagnosis without SSRI/SNRI use. SSRIs/SNRIs use may be associated with higher BP levels and this merits future prospective studies using ABPM to assess day and nighttime BP changes with SSRIs/SNRIs use.

Circadian variations in blood pressure and their implications for the administration of antihypertensive drugs: is dosing in the evening better than in the morning?

: Blood pressure (BP) follows a circadian rhythm with a physiological decrease during the night. Studies have demonstrated that nocturnal BP as well as its dipping pattern during night-time have a significant prognostic importance for mortality and the occurrence of cardiovascular events. Therefore, hypertension management guidelines recommend to ascertain that patients treated for hypertension have well controlled BP values around the clock. To improve hypertension control during the night and eventually further reduce cardiovascular events, it has been proposed by some to prescribe at least one antihypertensive medication at bedtime. In this review, we have examined the data which could support the benefits of prescribing BP-lowering drugs at bedtime. Our conclusion is that there is no convincing evidence that the administration of BP-lowering drugs in the evening provides any significant advantage in terms of quality of BP control, prevention of target organ damage or reduction of cardiovascular events. Before changing practice for unproven benefits, it would be wise to wait for the results of the ongoing trials that are addressing this issue.

Cardiovascular dysautonomia in Achalasia Patients: Blood pressure and heart rate variability alterations

Achalasia is a disease characterized by the inability to relax the esophageal sphincter due to a degeneration of the parasympathetic ganglion cells located in the wall of the thoracic esophagus. Achalasia has been associated with extraesophageal dysmotility, suggesting alterations of the autonomic nervous system (ANS) that extend beyond the esophagus. The purpose of the present contribution is to investigate whether achalasia may be interpreted as the esophageal manifestation of a more generalized disturbance of the ANS which includes alterations of heart rate and/or blood pressure. Therefore simultaneous non-invasive records of the heart inter-beat intervals (IBI) and beat-to-beat systolic blood pressure (SBP) of 14 patients (9 female, 5 male) with achalasia were compared with the records of 34 rigorously screened healthy control subjects (17 female, 17 male) in three different conditions: supine, standing up, and controlled breathing at 0.1 Hz, using a variety of measures in the time and spectral domains. Significant differences in heart rate variability (HRV) and blood pressure variability (BPV) were observed which seem to be due to cardiovagal damage to the heart, i.e., a failure of the ANS, as expected according to our hypothesis. This non-invasive methodology can be employed as an auxiliary clinical protocol to study etiology and evolution of achalasia, and other pathologies that damage ANS.

Relation between Blood Pressure Variability within a Single Visit and Stroke

Blood pressure variability (BPV) has been identified as an important risk factor for cardiovascular events. The white coat effect (WCE), which is measured as the first systolic blood pressure (SBP) measurement minus the mean of the second and third measurements, is a BPV indicator within a single visit. In total, 2,972 participants who had three measurements of BP within a single visit were included. The participants were divided into three groups based on their WCE percentiles: Group 1 (WCE_2.5-97.5, 2.5–97.5th percentiles of WCE), Group 2 (WCE_2.5, 0–2.4th percentiles of WCE), and Group 3 (WCE_97.5, 97.6–100th percentiles of WCE). A multiple logistic regression model was used to analyze the relationship between WCE and stroke after adjusting for cardiovascular disease risk factors. Compared with the WCE_2.5-97.5 group, the OR for stroke in the WCE_2.5 group was 2.78 (95% CI: 1.22, 6.36, p=0.015). After adjusting for cardiovascular factors, OR increased to 3.12 (95% CI: 1.22, 7.96, p=0.017). The OR of WCE for stroke was 0.93 (95%CI: 0.87, 0.99, p=0.036). BPV within a single visit is associated with stroke. The value and direction of the change may be important as well.

Metastasis of Breast Cancer Promoted by Circadian Rhythm Disruption due to Light/Dark Shift and its Prevention by Dietary Quercetin in Mice

Epidemiological studies have indicated that a disturbed circadian rhythm resulting from night-shift work is a potential risk factor for breast cancer. However, the mechanism of increased risk of breast cancer by night-shift work remains unclear, and there have been few in vivo studies conducted to definitively associate the two factors. In this study, BJMC3879Luc2 mouse breast cancer cells were transplanted into BALB/c mice. Mice were maintained under lighting conditions that modeled the two-shift system and were investigated for the effect of light/dark cycle disruption on tumor growth and lymph node metastasis. Circadian dysfunction, which was confirmed by measuring circadian locomotor activities using a nano tag device in our light/dark shift model, did not affect tumor growth. However, a significant increase in the number of lymph nodes with distant metastasis was observed. Neutrophil-to-lymphocyte ratio, which is an adverse prognostic factor of breast cancer and also indicator of inflammation, also increased. It has been demonstrated that a chronic inflammatory response is associated with cancer malignancy and poor prognosis in various cancers. These results suggest that night-shift work may also affect distant metastasis and prognosis. In addition, we investigated whether dietary quercetin has anti-metastatic activity against light/dark shift-induced metastasis. A diet containing 0.3 % quercetin significantly inhibited distant lymph node metastasis, particularly metastasis to the iliac and kidney lymph nodes. Our results contribute to our understandings of the effects of the external light environment on breast cancer metastasis and provide a glimpse into potential protective effects of dietary quercetin on light/dark disturbance-induced metastasis.

24-h ambulatory blood pressure variability and hypertensive nephropathy in Han Chinese hypertensive patients

Blood pressure (BP) is characterized by spontaneous oscillation over time, which is described as BP variability (BPV). The current study aimed to investigate whether short‐term BPV was correlated with hypertensive nephropathy in Han Chinese individuals with hypertension. A single‐center prospective cohort study of 300 Han Chinese participants with hypertension was conducted in Taiwan. Five different BPV parameters were derived from ambulatory BP monitoring (ABPM), including standard deviation (SD), weighted SD (wSD), coefficient of variation (CoV), successive variation (SV), and average real variability (ARV). Renal event was defined as > 50% reduction in baseline estimated glomerular filtration rate (eGFR). The average age of the participants was 63.5 years. The baseline eGFR was 84.5 mL/min/1.73 m². The participants were divided into two groups according to the wSD of systolic BP (SBP). Survival was assessed via a Kaplan‐Meier analysis. During the 4.2‐year follow‐up, the participants with the highest SBP wSD tertile had a greater number of renal events (6.0%) than their counterparts (0.5%) (log‐rank test, p = .007). The Cox proportional hazard regression model was used to assess the independent effects of BPV, and results showed that 24‐h SBP (HR = 1.105; 95% CI = 1.020–1.197, p = .015) and 24‐h DBP (HR = 1.162; 95% CI = 1.004–1.344, p = .044) were independently associated with renal events. However, BPV parameters were only associated with renal events univariately, but not after adjusting for baseline characteristics, 24‐h mean BP, and office BP. Therefore, the risk of hypertensive nephropathy was independently associated with 24‐h mean BP, but not with ambulatory BPV, in Han Chinese participants with hypertension.

Influence of elevated sleep-time blood pressure on vascular risk and hypertension-mediated organ damage

We report the analysis of 252 hypertensive patients whose blood pressure (BP) was assessed by around-the-clock ambulatory BP monitoring compared to office BP measurement during a follow-up investigation of 8.7 y (SD: 2.43 y) that evaluated the added value of measuring sleep-time BP values. We found that 37.3% of the patients had mismatched diagnoses between the two techniques of BP assessment, with 11.5% of the patients showing white-coat hypertension and 25.8% masked hypertension. Only 12.3% of the diagnosed and treated patients presented normal BP values. Nocturnal (sleep-time) hypertension was present in 70.63%. The sleep-time systolic BP mean was found to be an independent vascular risk factor (F = 9.005, p < .001), indirectly measured through the 10-year risk of morbidity and mortality. Additionally, the elevated sleep-time systolic BP mean was a better marker of subclinical hypertension-mediated organ damage (ρ = 0.19, p < .01) than either the awake (ρ = 0.168, p < .01) or 24 (ρ = 0.184, p < .01) systolic BP means. In conclusion, the accuracy and sleep-time measurements provided by ambulatory BP make it particularly relevant in hypertension diagnosis and management. The use of the ambulatory BP measurement method could end up modifying current therapeutic targets, with sleep-time systolic BP mean becoming a main one, in order to optimize hypertension control and reduce hypertension-related organ pathology and cardiovascular disease morbidity and mortality.

Identifying patterns of diurnal blood pressure variation among ELSA-Brasil participants

Ambulatory blood pressure monitoring (ABPM) is the gold standard method for the diagnosis of hypertension. ABPM provides a set of repeated measurements for blood pressure (BP), usually over 24 h. Traditional approaches characterize diurnal BP variation by single ABPM parameters such as average and standard deviation, regardless of the temporal nature of the data. In this way, information about the pattern of diurnal BP variation and relationship between parameters is lost. The objective of this study was to identify and characterize daily BP patterns considering the set of repeated measures from 24-h ABPM. A total of 859 adult participants of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) performed a 24-h ABPM record. Hypertension, sex, age, race/color, education, marital status, smoking, alcohol, physical activity, and BMI were the covariables analyzed. Techniques for longitudinal clustering, multinomial models, and models with mixed effects were used. Three daily BP patterns were identified. Daily BP patterns with high BP presented higher standard deviation and morning surge and lower nocturnal dipping. They showed greater systolic BP variability and faster rise than fall in diastolic BP during sleep. Hypertensive, "pardos," and men had greater odds to present these patterns. Daily BP patterns with high BP presented the worst profile concerning ABPM parameters associated with cardiovascular risk. The daily BP patterns identified contribute to the characterization of diurnal BP variation.

Personal exposure to fine particulate air pollutants impacts blood pressure and heart rate variability

Air pollution has increasingly been recognized as a major healthcare concern. Air pollution, particularly fine particulate matter (≤ 2.5 μm in aerodynamic diameter [PM_2.5]) has demonstrated an increase in adverse cardiovascular events. This study aimed to assess the cardiovascular response to personal exposure to different levels of PM_2.5. This prospective cohort study enrolled healthy volunteers aged ≥ 18 years with no cardiovascular disease. Study subjects carried personal exposure monitor of PM_2.5, digital thermo-hygrometer for temperature and humidity, 24-h blood pressure monitor, and continuous electrocardiogram monitor. Measurements were repeated twice with an interval of 6-12 months. Statistical models consisted of generalized estimation equations to various repeated measures of each subject. A total of 22 subjects were enrolled in this study between July 2018 and January 2019. Measurement was performed twice in all participants, and a total of 36 data were collected except for insufficient data collection. The mean age of the study population was 41.6 years, and 95% of the subjects were females. No study subjects had hypertension or other cardiovascular diseases. The average systolic blood pressure increased with higher PM_2.5 levels with marginal significance (0.22 mmHg [95% confidential intervals - 0.04 to 0.48 mmHg] per 10 μg/m³ of PM_2.5). All parameters for heart rate variability significantly decreased with a higher level of PM_2.5. In this study, we measured individual personal exposure to PM_2.5 by using a portable device. We found that 24-h exposure to high levels of PM_2.5 was associated with a significant decrease in heart rate variability, suggesting impaired autonomous nervous function.

Visit-to-visit blood pressure variability and renal outcomes: results from ONTARGET and TRANSCEND trials

AIMS

There is conflicting evidence on whether in treated hypertensive patients the risk of renal outcomes is associated with visit-to-visit SBP variability. Furthermore, limited evidence is available on how important is SBP variability for prediction of renal outcomes compared with on-treatment mean SBP. We addressed these issues in 28 790 participants of the Ongoing Treatment Alone and in combination with Ramipril Global End point Trial and Telmisartan Randomized AssessmeNt Study in ACE iNtolerant Subjects with Cardiovascular Disease trials.

METHODS AND RESULTS

SBP variability was expressed as the coefficient of variation of the mean with which it showed no relationship. SBP variability and mean values were obtained from five visits during the first 2 years of treatment after the end of the titration phase. Incidence of several renal outcomes (end-stage renal disease, doubling of serum creatinine, new microalbuminuria, new macroalbuminuria and their composite) was calculated from the third year of treatment onward. Patients were divided in quintiles of SBP-coefficient of variation (SBP-CV) or mean SBP, which exhibited superimposable mean blood pressure and SBP-CV values, respectively. A progressive increase of SBP-CV was not accompanied by a parallel increase in a widely adjusted (baseline and on-treatment confounders) risk of most renal outcomes (end-stage renal disease, new macroalbuminuria, new microalbuminuria and their composite) in the subsequent on-treatment years. In contrast, the adjusted risk of most renal outcomes increased progressively from the lowest to the highest quintile of on-treatment mean SBP. Progression from lowest to highest mean on-treatment SBP, but not SBP-CV, was also associated with a less frequent return to normoalbuminuria in patients with initial micro or macroalbuminuria. Renal outcome prediction was slightly improved by the combined use of SBP-CV and mean SBP quintiles.

CONCLUSION

Visit-to-visit SBP variability had no major predictive value for the risk of renal outcomes, which, in contrast, was sensitively predicted by mean on-treatment SBP. A further slight increase in prediction of renal outcomes was seen by combining on-treatment mean SBP and variability.

Blood Pressure Variability and Optimal Cerebral Perfusion Pressure-New Therapeutic Targets in Traumatic Brain Injury

BACKGROUND

Optimal cerebral perfusion pressure (CPPopt) is an autoregulatory-oriented target in the neurointensive care (NIC) of patients with traumatic brain injury (TBI), and deviation from CPPopt is associated with poor outcome. We recently found that blood pressure variability (BPV) is associated with deviation from CPPopt.

OBJECTIVE

To evaluate BPV and other variables related to deviation from CPPopt and to evaluate challenges and strategies for autoregulatory-oriented treatment in TBI.

METHODS

Data including arterial blood pressure and intracranial pressure (ICP) from 362 TBI patients treated at the NIC unit, Uppsala University Hospital, Sweden, between 2008 and 2016, were retrospectively analyzed day 2 to 5.

RESULTS

Higher BPV was a strong predictor of both CPP deviation below and above CPPopt after multiple regression analyses. There was no other explanatory variable for CPP deviation above CPPopt, whereas also higher ICP and worse autoregulation (higher pressure reactivity index) were associated with CPP deviation below CPPopt. A higher BPV was, in turn, explained by older age, lower ICP, higher mean arterial blood pressure, and higher slow arterial blood pressure amplitude (0.018-0.067 Hz).

CONCLUSION

BPV was strongly associated with deviation from CPPopt. High age is a risk factor for high BPV and hence CPP insults. Our treatment protocol is focused on avoiding CPP below 60 mm Hg. It is possible that a more restrictive upper level could generate more stable blood pressure and less deviation from CPPopt.

A Comparison of Non-Invasive Blood Pressure Measurement Strategies with Intra-Arterial Measurement

Introduction:

It is difficult to obtain an accurate blood pressure (BP) measurement, especially in the prehospital environment. It is not known fully how various BP measurement techniques differ from one another.

Study Objective:

The study hypothesized that there are differences in the accuracy of various non-invasive blood pressure (NIBP) measurement strategies as compared to the gold standard of intra-arterial (IA) measurement.

Methods:

The study enrolled adult intensive care unit (ICU) patients with radial IA catheters placed to measure radial intra-arterial blood pressure (RIBP) as a part of their standard care at a large, urban, tertiary-care Level I trauma center. Systolic blood pressure (SBP) was taken by three different NIBP techniques (oscillometric, auscultated, and palpated) and compared to RIBP measurements. Data were analyzed using the paired t-test with dependent samples to detect differences between RIBP measurements and each NIBP method. The primary outcome was the difference in RIBP and NIBP measurement. There was also a predetermined subgroup analysis based on gender, body mass index (BMI), primary diagnosis requiring IA line placement, and current vasoactive medication use.

Results:

Forty-four patients were enrolled to detect a predetermined clinically significant difference of 5mmHg in SBP. The patient population was 63.6% male and 36.4% female with an average age of 58.4 years old. The most common primary diagnoses were septic shock (47.7%), stroke (13.6%), and increased intracranial pressure (ICP; 13.6%). Most patients were receiving some form of sedation (63.4%), while 50.0% were receiving vasopressor medication and 31.8% were receiving anti-hypertensive medication. When compared to RIBP values, only the palpated SBP values had a clinically significant difference (9.88mmHg less than RIBP; P < .001). When compared to RIBP, the oscillometric and auscultated SBP readings showed statistically but not clinically significant lower values. The palpated method also showed a clinically significant lower SBP reading than the oscillometric method (5.48mmHg; P < .001) and the auscultated method (5.06mmHg; P < .001). There was no significant difference between the oscillometric and auscultated methods (0.42mmHg; P = .73).

Conclusion:

Overall, NIBPs significantly under-estimated RIBP measurements. Palpated BP measurements were consistently lower than RIBP, which was statistically and clinically significant. These results raise concern about the accuracy of palpated BP and its pervasive use in prehospital care. The data also suggested that auscultated and oscillometric BP may provide similar measurements.

Blood Pressure Increases Before Pulse Rate During the Nocturnal Period in Hypertensive Patients

Ambulatory blood pressure monitoring (ABPM) is used for the evaluation of out-of-office blood pressure (BP), however, knowledge concerning the detailed behavior of nocturnal blood pressure (BP) and pulse rate (PR) is limited.A total of 190 participants (64 ± 15 years, 46.3% males) underwent ABPM for diagnosis of hypertension or evaluation of hypertensive therapy. BP and PR were measured automatically by the oscillometric method. From the hourly average ABPM values, the nocturnal time courses (0 AM to 6 AM) of SBP and PR were determined and compared to each other.In general, SBP fell to the lowest level at around midnight and started to increase progressively towards dawn while PR stayed unchanged until 7 AM. Age and gender affected the time course of SBP, most distinctly in the female patients aged ≥ 60 years. The time course of the increase of SBP was very similar in the patients, with BP dipping and non-dipping. The cardiothoracic ratio (CTR) slightly and renal dysfunction modestly facilitated the increase of nocturnal SBP. The nocturnal increase in SBP was not accompanied by an increase of PR in any group or subgroup. The pathophysiology and clinical significance of the early and exclusive increase in nocturnal BP need to be investigated.Average ABPM values in these hypertensive patients showed that BP starts to increase toward dawn without an increase in PR and that this discrepant behavior between BP and RP was most distinct in females 60 or older. The mechanism and clinical significance of such a discordant variation in BP and PR need to be elucidated.

Cross-sectional centiles of blood pressure by age and sex: a four-hospital database retrospective observational analysis

OBJECTIVES

National guidelines for identifying physiological deterioration and sepsis in hospitals depend on thresholds for blood pressure that do not account for age or sex. In populations outside hospital, differences in blood pressure are known to occur with both variables. Whether these differences remain in the hospitalised population is unknown. This database analysis study aims to generate representative centiles to quantify variations in blood pressure by age and sex in hospitalised patients.

DESIGN

Retrospective cross-sectional observational database analysis.

SETTING

Four near-sea-level hospitals between April 2015 and April 2017 PARTICIPANTS: 75 342 adult patients who were admitted to the hospitals and had at least one set of documented vital sign observations within 24 hours before discharge were eligible for inclusion. Patients were excluded if they died in hospital, had no vital signs 24 hours prior to discharge, were readmitted within 7 days of discharge, had missing age or sex or had no blood pressure recorded.

RESULTS

Systolic blood pressure (SBP) for hospitalised patients increases with age for both sexes. Median SBP increases from 122 (CI: 121.1 to 122.1) mm Hg to 132 (CI: 130.9 to 132.2) mm Hg in men, and 114 (CI: 113.1 to 114.4) mm Hg to 135 (CI: 134.5 to 136.2) mm Hg in women, between the ages of 20 and 90 years. Diastolic blood pressure peaked around 50 years for men 76 (CI: 75.5 to 75.9) mm Hg and women 69 (CI: 69.0 to 69.4) mm Hg. The blood pressure criterion for sepsis, systolic <100 mm Hg, was met by 2.3% of younger (20-30 years) men and 3.5% of older men (81-90 years). In comparison, the criterion was met by 9.7% of younger women and 2.6% of older women.

CONCLUSION

We have quantified variations in blood pressure by age and sex in hospitalised patients that have implications for recognition of deterioration. Nearly 10% of younger women met the blood pressure criterion for sepsis at hospital discharge.

Day and Night Changes of Cardiovascular Complexity: A Multi-Fractal Multi-Scale Analysis

Recently, a multifractal-multiscale approach to detrended fluctuation analysis (DFA) was proposed to evaluate the cardiovascular fractal dynamics providing a surface of self-similarity coefficients α(q,τ), function of the scale τ, and moment order q. We hypothesize that this versatile DFA approach may reflect the cardiocirculatory adaptations in complexity and nonlinearity occurring during the day/night cycle. Our aim is, therefore, to quantify how α(q, τ) surfaces of cardiovascular series differ between daytime and night-time. We estimated α(q,τ) with -5 ≤ q ≤ 5 and 8 ≤ τ ≤ 2048 s for heart rate and blood pressure beat-to-beat series over periods of few hours during daytime wake and night-time sleep in 14 healthy participants. From the α(q,τ) surfaces, we estimated short-term (<16 s) and long-term (from 16 to 512 s) multifractal coefficients. Generating phase-shuffled surrogate series, we evaluated short-term and long-term indices of nonlinearity for each q. We found a long-term night/day modulation of α(q,τ) between 128 and 256 s affecting heart rate and blood pressure similarly, and multifractal short-term modulations at q < 0 for the heart rate and at q > 0 for the blood pressure. Consistent nonlinearity appeared at the shorter scales at night excluding q = 2. Long-term circadian modulations of the heart rate DFA were previously associated with the cardiac vulnerability period and our results may improve the risk stratification indicating the more relevant α(q,τ) area reflecting this rhythm. Furthermore, nonlinear components in the nocturnal α(q,τ) at q ≠ 2 suggest that DFA may effectively integrate the linear spectral information with complexity-domain information, possibly improving the monitoring of cardiac interventions and protocols of rehabilitation medicine.

Alteration autonomic control of cardiac function during hemodialysis predict cardiovascular outcomes in end stage renal disease patients

Dialysis-induced hemodynamic instability has been associated with increased risk of cardiovascular (CV) mortality. However, the control mechanisms beneath the dynamic BP changes and cardiac function during hemodialysis and subsequent CV events are not known. We hypothesize that the impaired hemodynamic control can be prognostic indicators for subsequent CV events in end stage renal diseaes (ESRD) patients. To explore the association of hemodynamic parameters and CV events in hemodialysis patients, we enrolled ESRD patients who received chronic hemodialysis without documented atherosclerotic cardiovascular disease and hemodynamic parameters were continuously obtained from the impedance cardiography during hemodialysis. A total of 35 patients were enrolled. 16 patients developed hospitalized CV events. The statistical properties [coefficient of variance (standard deviation / mean value; CoV)] of hourly beat-to-beat dynamics of hemodynamic parameters were calculated. The CoV of stroke volume (SV) and cardiac index (CI) between the 1^st and 2^nd hour of dialysis were significantly increased in patients without CV events compared to those with CV events. Higher CoV of SV_diff and CI_diff were significantly correlated with longer CV event-free survival, and the area under the receiver operating characteristic (ROC) curve showed fair overall discriminative power (0.783 and 0.796, respectively). The responses of hemodynamic control mechanisms can be independent predictive indexes for lower hospitalized CV events, which implies that these patients who have better autonomic control systems may have better CV outcomes.

Prognostic value of average real variability of systolic blood pressure in elderly treated hypertensive patients

OBJECTIVE

The independent prognostic significance of ambulatory blood pressure variability in the elderly is incompletely clear. We investigated the prognostic value of average real variability of 24-hour blood pressure in elderly treated hypertensive patients.

METHODS

The occurrence of a combined end-point including stroke, coronary events, heart failure requiring hospitalization and peripheral revascularization was evaluated in 757 elderly treated hypertensive patients. According to tertiles of average real variability of 24-hour systolic blood pressure patients were classified as having low (≤8.66 mmHg; n = 252), medium (8.67-10.05 mmHg; n = 252) or high (>10.05 mmHg; n = 253) average real variability.

RESULTS

During the follow-up (6.9 ± 3.4 years, range 0.4-12.9 years), 195 events occurred. The event rate of the population was 3.74 per 100 patient-years. After adjustment for age, sex, previous events, diabetes, estimated glomerular filtration rate, left ventricular hypertrophy, left atrial enlargement, asymptomatic left ventricular systolic dysfunction at baseline, 24-hour systolic blood pressure, non-dipping and dipping with high morning surge of blood pressure, patients with high average real variability were at higher cardiovascular risk than those with low average real variability (hazard ratio 1.64, 95% confidence interval 1.12-2.40).

CONCLUSIONS

In elderly treated hypertensive patients, high average real variability of 24-hour systolic blood pressure is associated with higher cardiovascular risk independently of other risk markers, average 24-hour systolic blood pressure and circadian blood pressure changes.

The impact of systolic and diastolic blood pressure variability on mortality is age dependent: Data from the Dublin Outcome Study

Background

Twenty-four-hour blood pressure variability (BPV) is independently related to cardiovascular outcomes, but limited and conflicting evidence is available on the relative prognostic importance of systolic and diastolic BPV. The aim of this study was to verify the hypothesis that the association of systolic and diastolic blood pressure variability over 24 h with cardiovascular mortality in untreated subjects is affected by age.

Design and methods

The study included 9154 untreated individuals assessed for hypertension between 1982 and 2002 in the frame of the Dublin Outcome Study, in which 24 h ambulatory blood pressure monitoring was obtained (age 54.1 ± 14.3 years, 47% males). The association of short-term systolic and diastolic blood pressure variability with cardiovascular and all-cause mortality in the entire sample and separately in younger and older age subgroups was assessed over a median follow-up period of 6.3 years.

Results

Diastolic BPV was directly and independently related to cardiovascular mortality (adjusted hazard ratio (adjHR) for daytime standard deviation 1.16 (95% confidence interval 1.08–1.26)) with no significant differences among age groups. Conversely, systolic BPV was independently associated with cardiovascular mortality only in younger (<50 years) subjects (adjHR for daytime standard deviation 1.72 (95% confidence interval 1.33–2.23)), superseding the predictive value of diastolic BPV in this group.

Conclusions

Diastolic short-term BPV independently predicts cardiovascular mortality in hypertensive subjects at all ages, while systolic BPV seems a particularly strong predictor in young adults. If confirmed, these findings might improve the understanding of the prognostic value of BPV, with new perspectives for its possible clinical application.

Risk Stratification in Idiopathic Dilated Cardiomyopathy Patients Using Cardiovascular Coupling Analysis

Cardiovascular diseases are one of the most common causes of death; however, the early detection of patients at high risk of sudden cardiac death (SCD) remains an issue. The aim of this study was to analyze the cardio-vascular couplings based on heart rate variability (HRV) and blood pressure variability (BPV) analyses in order to introduce new indices for noninvasive risk stratification in idiopathic dilated cardiomyopathy patients (IDC). High-resolution electrocardiogram (ECG) and continuous noninvasive blood pressure (BP) signals were recorded in 91 IDC patients and 49 healthy subjects (CON). The patients were stratified by their SCD risk as high risk (IDC_HR) when after two years the subject either died or suffered life-threatening complications, and as low risk (IDC_LR) when the subject remained stable during this period. Values were extracted from ECG and BP signals, the beat-to-beat interval, and systolic and diastolic blood pressure, and analyzed using the segmented Poincaré plot analysis (SPPA), the high-resolution joint symbolic dynamics (HRJSD) and the normalized short time partial directed coherence methods. Support vector machine (SVM) models were built to classify these patients according to SCD risk. IDC_HR patients presented lowered HRV and increased BPV compared to both IDC_LR patients and the control subjects, suggesting a decrease in their vagal activity and a compensation of sympathetic activity. Both, the cardio -systolic and -diastolic coupling strength was stronger in high-risk patients when comparing with low-risk patients. The cardio-systolic coupling analysis revealed that the systolic influence on heart rate gets weaker as the risk increases. The SVM IDC_LR vs. IDC_HR model achieved 98.9% accuracy with an area under the curve (AUC) of 0.96. The IDC and the CON groups obtained 93.6% and 0.94 accuracy and AUC, respectively. To simulate a circumstance in which the original status of the subject is unknown, a cascade model was built fusing the aforementioned models, and achieved 94.4% accuracy. In conclusion, this study introduced a novel method for SCD risk stratification for IDC patients based on new indices from coupling analysis and non-linear HRV and BPV. We have uncovered some of the complex interactions within the autonomic regulation in this type of patient.

Interactions between cardiac activity and conscious somatosensory perception

Fluctuations in the heart's activity can modulate the access of external stimuli to consciousness. The link between perceptual awareness and cardiac signals has been investigated mainly in the visual and auditory domain. Here, we investigated whether the phase of the cardiac cycle and the prestimulus heart rate influence conscious somatosensory perception. We also tested how conscious detection of somatosensory stimuli affects the heart rate. Electrocardiograms (ECG) of 33 healthy volunteers were recorded while applying near-threshold electrical pulses at a fixed intensity to the left index finger. Conscious detection was not uniformly distributed across the cardiac cycle but significantly higher in diastole than in systole. We found no evidence that the heart rate before a stimulus influenced its detection, but hits (correctly detected somatosensory stimuli) led to a more pronounced cardiac deceleration than misses. Our findings demonstrate interactions between cardiac activity and conscious somatosensory perception, which highlights the importance of internal bodily states for sensory processing beyond the auditory and visual domain.

Gender Difference of the Relationship between Arterial Stiffness and Blood Pressure Variability in Participants in Prehypertension

Aim. The association of pressure load with elasticity in vascular system has not been studied fully. We proposed a hypothesis whether gender could modify the association of blood pressure variability (BPV) and arterial stiffness assessed by carotid-femoral pulse wave velocity (CF-PWV) in prehypertensive patients. Methods. 24h ambulatory blood pressure monitoring (24h-ABPM) and CF-PWV were measured in 723 participants with prehypertension. Univariate and multivariate regression analyses of these clinical and biological parameters were performed in total population, male and female. Results. A total of 723 participants (mean age 59.76 ± 12.37years, male 329 and female 394) were enrolled into the study. Compared with female, body mass index (BMI), fasting plasma glucose (FPG), uric acid (UA), and homocysteine (HCY) were significantly higher (all p < 0.05). Arterial stiffness (CF-PWV, male versus female, 10.89 ± 2.50 versus 10.33 ± 2.13 m/s, p=0.004) and BPVs (male versus female, 24 h SBPV 13.2 ± 5.11 versus 13.03 ± 5.20; 24 h DBPV 10.34 ± 3.87 versus 9.64 ± 3.59; N SBPV 11.90 ± 6.60 versus 10.94 ± 4.79; N DBPV 9.64 ± 5.87 versus 8.20 ± 4.48, all p<0.05) were higher in male. Multivariable linear regression analysis showed that 24 h BPV were linearly and positively related to CF-PWV in total population (24h SBPV, B=0.033; 24 h DBPV, B=0.035, both P<0.05) and female (24h SBPV, B=0.041; 24h DBPV, B=0.067, both P<0.05) independent of traditional risk factors and medications. Conclusion. BPV was independently associated with arterial stiffness in total population and the relation was modified by gender. 24 h BPVs in prehypertensive patients were useful to identify the early arterial stiffness. Clinical Trials Registration. This trial was registered with Clinical Trials.gov Identifier: NCT02569268.

Effect of antihypertensive treatment on 24-h blood pressure variability: pooled individual data analysis of ambulatory blood pressure monitoring studies based on olmesartan mono or combination treatment

Objective:

To evaluate the impact of olmesartan alone or combined with one to three antihypertensive drugs on 24-h blood pressure variability (BPV) and on distribution of BP reduction in a pooled individual data analysis of 10 double-blind, randomized, ambulatory BP monitoring (ABPM) studies.

Methods:

ABPMs were performed before and after 6–12 weeks of treatment with placebo (n = 119), active control monotherapy [n = 1195, angiotensin-converting enzyme inhibitors (ACEIs), angiotensin II receptor blockers (ARBs), dihydropyridine calcium channel blockers (DCCBs)] olmesartan monotherapy (n = 1410), active control dual combination [n = 79, DCCB + thiazide diuretic (TD)], olmesartan dual combination (n = 637, DCCB or TD), and triple combination therapy (n = 102, DCCB+TD). 24-h BPV was calculated as unweighted or weighted SD of the mean BP, and average real variability. BP control was assessed by smoothness index and treatment-on-variability index.

Results:

The greatest effect on 24-h systolic BPV/diastolic BPV was observed under olmesartan triple [−2.6/−1.9; −1.9/−1.3; −1.4/−1.3 mmHg] and active control dual combination [−1.8/−1.4; −1.9/−1.5; −1.2/−1.1 mmHg]. Smoothness indexes and treatment-on-variability indexes were significantly (P = 0.0001) higher under olmesartan dual (1.53/1.22, 1.67/1.29, 2.05/1.59), olmesartan triple (2.47/1.85, 2.80/2.06, 3.64/2.67), or active control dual combination (1.70/1.26, 1.85/1.33, 2.29/1.65) than under monotherapies (control: 0.86/0.73, 0.80/0.65, 1.01/0.82; olmesartan: 1.02/0.86, 0.95/0.78, 1.23/1.00). They were also greater in patients receiving high-dose olmesartan monotherapy or high-dose olmesartan dual combination than in the corresponding low-dose group.

Conclusion:

Olmesartan plus a DCCB and/or a TD produces a larger, more sustained, and smoother BP reduction than placebo and monotherapies, a desirable feature for a more effective prevention of the cardiovascular consequences of uncontrolled hypertension.

Nondipping Pattern and Cardiovascular and Renal Damage in a Population-Based Study (The STANISLAS Cohort Study)

OBJECTIVE

The attenuation of physiological nocturnal decline of blood pressure (BP)-called nondipper pattern-has previously been reported to be associated with target organ damage in hypertensive subjects. However, this association remains debated and poorly studied in normotensive patients. This study aimed to investigate the association between nondipper pattern and subclinical cardiovascular and renal damage in an initially healthy population-based cohort study.

METHODS

The STANISLAS Cohort is a single-center, familial longitudinal cohort composed of 1,006 families (4,295 subjects) recruited in 1993-1995 for a 5-year periodic health examination. A total of 1,334 subjects from the 4th visit (2011-2016) of the STANISLAS cohort were included. This 4th examination included estimated glomerular filtration rate, albumin/creatinine ratio, pulse wave velocity, central systolic BP, carotid intima-media thickness and distensibility, left ventricular mass index, left ventricular hypertrophy, diastolic dysfunction, and ambulatory blood pressure monitoring (ABPM). Nondipping status was defined as a mean reduction in systolic BP (SBP) or diastolic BP (DBP) lower than 10% during nighttime.

RESULTS

Data were obtained from 798 normotensive subjects (45 ± 14 years, 395 [49%] nondippers, SBP/DBP mmHg 24 hours: 116/71 ± 7/5) and 536 hypertensive patients (56 ± 11 years, 257 [48%] nondippers, SBP/DBP mmHg 24 hours: 127/78 ± 10/7). Mean 24-hour and daytime ABPM measurements were within the normal range, even in hypertensive participants (19% treated). The nondipping pattern was not associated with cardiovascular or renal alterations in this population.

CONCLUSION

In this middle-aged population with an overall 24-hour optimal BP control, the nondipper pattern was not associated with increased cardiovascular or renal damage.

Closed-Loop Cardiovascular Interactions and the Baroreflex Cardiac Arm: Modulations Over the 24 h and the Effect of Hypertension

Closed-loop models of the interactions between blood pressure (BP) and heart rate variations allow for estimation of baroreflex sensitivity (feedback effects of BP changes on heart rate) while also considering the feedforward effects of heart rate on BP. Our study is aimed at comparing modulations of feedback and feedforward couplings over 24 h in normotensive and hypertensive subjects, by assessing closed-loop baroreflex models in ambulatory conditions. Continuous intra-arterial BP recordings were performed for 24 h in eight normotensive and eight hypertensive subjects. Systolic BP (SBP) and pulse interval (PI) beat-by-beat series were analyzed by an autoregressive moving average model over consecutive 6-min running windows, estimating closed-loop feedback and feedforward gains in each window. The open-loop feedback gain was estimated for comparison. Normotensive and hypertensive patients were compared during wake (18:00–22:00) and sleep (23:00–5:00) periods by a mixed-effect linear model at p < 0.05. In both groups feedback (feedforward) gain averaged values were higher (lower) in sleep than in wake. Moreover, the closed-loop feedback gain was higher in normotensive subjects both in wake and sleep, whereas the closed-loop feedforward gain was higher in hypertensive subjects during sleep. By contrast, no significant differences were found between the normotensive and hypertensive groups for the open-loop feedback gain. Therefore, the closed-loop SBP-PI model can detect circadian alterations in the feedforward gain of PI on SBP and derangements of spontaneous baroreflex sensitivity in hypertension not detectable with the open-loop approach. These findings may help to obtain a more comprehensive assessment of the autonomic dysfunction underlying hypertension and for the in-depth evaluation of the benefits of rehabilitation procedures on autonomic cardiovascular modulation.