Ambulatory Blood Pressure Monitoring (ABPM) as the reference standard for diagnosis of hypertension and assessment of vascular risk in adults

Blood Pressure on Ambulatory Monitoring and Risk for Cardiovascular Disease and All-Cause Mortality: Ecological Validity or Measurement Reliability?

BACKGROUND

The association with cardiovascular disease (CVD) is stronger for mean systolic blood pressure (SBP) estimated using ambulatory blood pressure monitoring (ABPM) vs. office measurements. Determining whether this is due to ABPM providing more measurement reliability or greater ecological validity can inform its use.

METHODS

We estimated the association of mean SBP based on 2 office measurements and 2, 5, 10, and 20 measurements on ABPM with incident CVD in the Jackson Heart Study (n = 773). Hazard ratios (HRs) for CVD were estimated per standard deviation higher mean SBP. CVD events were defined by incident fatal or non-fatal stroke, non-fatal myocardial infarction, or fatal coronary heart disease.

RESULTS

There were 80 CVD events over a median of 15 years. The adjusted HRs for incident CVD were 1.03 (95% CI: 0.90-1.19) for mean office SBP and 1.30 (95% CI: 1.12-1.50), 1.34 (95% CI: 1.15-1.56), 1.36 (95% CI: 1.17-1.59), and 1.38 (95% CI: 1.17-1.63) for mean SBP using the first 2, 5, 10, and 20 ABPM readings. The difference in the HRs for incident CVD ranged from 0.26 (95% CI: 0.07-0.46) to 0.35 (95% CI: 0.15-0.54) when comparing mean office SBP vs. 2, 5, 10, or 20 sequential ABPM readings. The association with incident CVD was also stronger for mean SBP based on 2, 5, 10, and 20 randomly selected ABPM readings vs. 2 office readings.

CONCLUSIONS

Mean SBP based on 2 ABPM readings vs. 2 office measurements had a stronger association with CVD events. The increase in the strength of the association with more ABPM readings was small.

Pre-eclampsia as a predictor of early-onset cardiovascular impairment among young women (PREECARDIA study): protocol for a prospective cohort study

INTRODUCTION

Pre-eclampsia is a pregnancy-related complication estimated to affect up to 8% of pregnancies worldwide. It is associated with an increased risk of postpartum sustained hypertension, coronary artery disease, cerebrovascular disease, peripheral arterial disease and cardiovascular-related mortality. Nevertheless, these associations have seldom been addressed in younger women from sub-Saharan Africa (SSA). Hence, this study aims to assess the association between pre-eclampsia and cardiovascular impairment within the first year after delivery, among younger women in SSA.

METHODS AND ANALYSIS

This is a prospective cohort study conducted at Hospital Nacional Simão Mendes in Bissau, Guinea-Bissau. A total of 230 pregnant women aged below 25 years (115 diagnosed with pre-eclampsia and 115 normotensive age-matched pregnancies), will be enrolled after their 20th gestational week. Exclusion criteria include diabetes, hypertension or other serious maternal diseases present before pregnancy. Participants will be assessed at baseline (pre-labour period), 4 and 12 months after delivery; evaluations started in March 2023 and are expected to end in December 2026. At each follow-up assessment, the women will have their blood pressure measured with a digital sphygmomanometer and a 24-hour ambulatory blood pressure monitor. Cardiac and renal function will be assessed using echocardiography and laboratory testing, respectively. Primary outcomes include the mean differences in cardiovascular and renal parameters between women who had pre-eclampsia and those who had normotensive pregnancies. Age, parity, age at first pregnancy, family history of cardiovascular diseases, smoking habits, gestational diabetes diagnosed before pre-eclampsia, body mass index and labour complications will be considered a priori as potential confounders of the association between pre-eclampsia and postpartum cardiovascular impairment.

ETHICS AND DISSEMINATION

This study was approved by the Comité Nacional de Ética em Pesquisa na Saúde, Guinea-Bissau (008/CNES/INASA/2023), and participants provide written informed consent. Results will be disseminated among the scientific community and the public.

Simultaneous 24-h ambulatory blood pressure measurement on both arms: a consideration for improving hypertension management

OBJECTIVE

Arterial hypertension is one of the common treatment goals in today's medicine. 24-h ambulatory blood pressure measurement (ABPM) performed by oscillometric cuff-based devices is considered as the gold standard in hypertension diagnostics. This study aims at examining the measurement accuracy of a widely used, ABPM device.

METHODS

Fifty-two young and healthy participants underwent simultaneous 24-h ABPM on the left and the right upper arm using two Boso/A&D TM-2430 oscillometric cuff-based devices. Pressure curves of the cuffs, as well as hydrostatic pressure difference between the cuffs were recorded.

RESULTS

The mean differences between both simultaneous measurements were 1.16 mmHg with limits of agreement of 36.23 mmHg for SBP and 1.32 mmHg with limits of agreement of 32.65 mmHg for DBP. Excluding measurements where the pressure curves were disturbed and correcting for hydrostatic pressure difference between the cuffs, reduced the measurement error. However, limits of agreement remained around 20 mmHg. There were large differences in hypertension grading and dipping pattern classification between simultaneous measurements on the left and right arm.

CONCLUSION

The cuff-based ABPM device reveals notable measurement uncertainties, influencing hypertension grading, dipping pattern classification and blood pressure variability. These effects are attributed in part to disturbances during cuff deflation and hydrostatic influences. Nonetheless, ABPM has shown its clinical values in several studies, while this study underscores its still unlocked potential to improve hypertension management.

Threshold values of brachial cuff-measured arterial stiffness indices determined by comparisons with the brachial-ankle pulse wave velocity: a cross-sectional study in the Chinese population

Background

Arterial Velocity-pulse Index (AVI) and Arterial Pressure-volume Index (API), measured by a brachial cuff, have been demonstrated to be indicative of arterial stiffness and correlated with the risk of cardiovascular events. However, the threshold values of AVI and API for screening increased arterial stiffness in the general population are yet to be established.

Methods

The study involved 860 subjects who underwent general physical examinations (M/F = 422/438, age 53.4 ± 12.7 years) and were considered to represent the general population in China. In addition to the measurements of AVI, API and brachial-ankle pulse wave velocity (baPWV), demographic information, arterial blood pressures, and data from blood and urine tests were collected. The threshold values of AVI and API were determined by receiver operating characteristic (ROC) analyses and covariate-adjusted ROC (AROC) analyses against baPWV, whose threshold for diagnosing high arterial stiffness was set at 18 m/s. Additional statistical analyses were performed to examine the correlations among AVI, API and baPWV and their correlations with other bio-indices.

Results

The area under the curve (AUC) values in ROC analysis for the diagnosis with AVI/API were 0.745/0.819, 0.788/0.837, and 0.772/0.825 (95% CI) in males, females, and all subjects, respectively. Setting the threshold values of AVI and API to 21 and 27 resulted in optimal diagnosis performance in the total cohort, whereas the threshold values should be increased to 24 and 29, respectively, in order to improve the accuracy of diagnosis in the female group. The AROC analyses revealed that the threshold values of AVI and API increased markedly with age and pulse pressure (PP), respectively.

Conclusions

With appropriate threshold values, AVI and API can be used to perform preliminary screening for individuals with increased arterial stiffness in the general population. On the other hand, the results of the AROC analyses imply that using threshold values adjusted for confounding factors may facilitate the refinement of diagnosis. Given the fact that the study is a cross-sectional one carried out in a single center, future multi-center or follow-up studies are required to further confirm the findings or examine the value of the threshold values for predicting cardiovascular events.

Artificial Intelligence in Hypertension Management: An Ace up Your Sleeve

Arterial hypertension (AH) is a progressive issue that grows in importance with the increased average age of the world population. The potential role of artificial intelligence (AI) in its prevention and treatment is firmly recognized. Indeed, AI application allows personalized medicine and tailored treatment for each patient. Specifically, this article reviews the benefits of AI in AH management, pointing out diagnostic and therapeutic improvements without ignoring the limitations of this innovative scientific approach. Consequently, we conducted a detailed search on AI applications in AH: the articles (quantitative and qualitative) reviewed in this paper were obtained by searching journal databases such as PubMed and subject-specific professional websites, including Google Scholar. The search terms included artificial intelligence, artificial neural network, deep learning, machine learning, big data, arterial hypertension, blood pressure, blood pressure measurement, cardiovascular disease, and personalized medicine. Specifically, AI-based systems could help continuously monitor BP using wearable technologies; in particular, BP can be estimated from a photoplethysmograph (PPG) signal obtained from a smartphone or a smartwatch using DL. Furthermore, thanks to ML algorithms, it is possible to identify new hypertension genes for the early diagnosis of AH and the prevention of complications. Moreover, integrating AI with omics-based technologies will lead to the definition of the trajectory of the hypertensive patient and the use of the most appropriate drug. However, AI is not free from technical issues and biases, such as over/underfitting, the "black-box" nature of many ML algorithms, and patient data privacy. In conclusion, AI-based systems will change clinical practice for AH by identifying patient trajectories for new, personalized care plans and predicting patients' risks and necessary therapy adjustments due to changes in disease progression and/or therapy response.

Higher daytime systolic BP, prepregnancy BMI and an elevated sFlt-1/PlGF ratio predict the development of hypertension in normotensive pregnant women

BACKGROUND

The risk of hypertensive disorders of pregnancy (HDP) varies in women with gestational diabetes mellitus (GDM), depending on the degree of insulin resistance and is also influenced by obesity. The aim of this study was to evaluate clinical features, blood pressure (BP) profiles and inflammatory markers, to identify patients with an elevated risk of developing HDP.

METHODS

A total of 146 normotensive pregnant women were studied. We analysed the relationships of BP profiles detected by ambulatory blood pressure monitoring (ABPM) with serum biomarkers and angiogenic factors and their association with the development of HDP.

RESULTS

Fourteen (9.6%) women developed HDP, of which 11 had GDM and 8 had obesity. Women with HDP had higher values of 24-h and daytime systolic/diastolic BP (113/69 vs. 104/64; 115/72 vs. 106/66 mmHg, respectively; p <  0.05). Higher levels of leptin (10.97 ± 0.82 vs. 10.2 ± 1.11; p = 0.018) andmonocyte chemoattractant protein-1 (MCP-1) (5.24 ± 0.60 vs. 4.9 ± 0.55; p = 0.044) and a higher soluble fms-like tyrosine kinase-1/placental growth factor (sFlt-1/PlGF) ratio (4.37 ± 2.2 vs. 2.2 ± 1.43; p = 0.003) were also observed in the HDP patients. Multivariate analysis showed that a higher sFlt-1/PlGF ratio was associated with an increased risk of developing HDP [OR = 2.02; IC 95%: 1.35-3.05]. Furthermore, higher daytime systolic BP [OR = 1.27; IC 95% 1.00-1.26] and prepregnancy body mass index (BMI) [OR = 1.14; IC 95%: 1.01-1.30] significantly increased the risk of developing HDP.

CONCLUSIONS

Higher daytime systolic BP values, prepregnancy BMI and the sFlt-1/PlGF ratio are useful for identifying normotensive pregnant women with an increased risk of developing HDP.

Serial assessment of thrombogenicity and hemodynamics in patients with type II diabetes in a clinical research unit: Evidence for circadian variations in clot formation

BACKGROUND

Circadian fluctuations in thrombogenicity and hemostasis play a role in acute cardiovascular thrombotic events occurring in the early morning hours. There is a lack of data assessing thrombogenicity, platelet function, and hemodynamics to investigate diurnal variations in a high cardiovascular risk population.

METHODS

This was an exploratory, single-center study conducted in aspirin-treated patients with Type II Diabetes Mellitus (T2DM) (n = 37) with documented vascular disease and/or multiple cardiovascular risk factors. Hemodynamic monitoring and blood sample collection for thromboelastography (TEG) and platelet function testing were done serially at 7-9 AM (morning), 7-9 PM (evening), 11 PM-1 AM (night), and at 5-7 AM (awakening).

RESULTS

R-value measured by TEG was shorter during awakening hours than during the night and day hours (p < 0.05). There were no changes in platelet reactivity in response to arachidonic acid, adenosine diphosphate, and collagen between time points. Pulse pressure (PP) was highest during awakening hours (p < 0.05).

CONCLUSION

Study findings provide a mechanistic explanation for increased thrombotic events observed in the early waking hours among diabetics with multiple cardiovascular risk factors. The role of chronotherapy in reducing coagulability and PP to improve clinical outcomes should be explored.

Improving Cuff-Less Continuous Blood Pressure Estimation with Linear Regression Analysis

In this work, the authors investigate the cuff-less estimation of continuous BP through pulse transit time (PTT) and heart rate (HR) using regression techniques, which is intended as a first step towards continuous BP estimation with a low error, according to AAMI guidelines. Hypertension (the ‘silent killer’) is one of the main risk factors for cardiovascular diseases (CVDs), which are the main cause of death worldwide. Its continuous monitoring can offer a valid tool for patient care, as blood pressure (BP) is a significant indicator of health and, using it together with other parameters, such as heart and breath rates, could strongly improve prevention of CVDs. The novelties introduced in this work are represented by the implementation of pre-processing and by the innovative method for features research and features processing to continuously monitor blood pressure in a non-invasive way. Currently, invasive methods are the only reliable methods for continuous monitoring, while non-invasive techniques measure the values every few minutes. The proposed approach can be considered the first step for the integration of these types of algorithms on wearable devices, in particular on those developed for the SINTEC project.

Pharmacogenomics and circadian rhythms as mediators of cardiovascular drug-drug interactions

This article summarizes the current literature and documents new evidence concerning drug-drug interactions (DDI) stemming from pharmacogenomic and circadian rhythm determinants of therapies used to treat common cardiovascular diseases (CVD), such as atherosclerosis and hypertension. Patients with CVD often have more than one pathophysiologic condition, namely metabolic syndromes, hypertension, hyperlipidemia, and hyperglycemia, among others, which necessitate polytherapeutic or polypharmaceutic management. Interactions between drugs, drugs and food/food supplements, or drugs and genetic/epigenetic factors may have adverse impacts on the cardiovascular and other systems of the body. The mechanisms underlying cardiovascular DDI may involve the formation of a complex pharmacointeractome, including the absorption, distribution, metabolism, and elimination of drugs, which affect their respective bioavailability, efficacy, and/or harmful metabolites. The pharmacointeractome of cardiovascular drugs is likely operated with endogenous rhythms controlled by circadian clock genes. Basic and clinical investigations have improved the knowledge and understanding of cardiovascular pharmacogenomics and pharmacointeractomes, and additionally they have presented new evidence that the staging of deterministic circadian rhythms, according to the dosing time of drugs, e.g., upon awakening vs. at bedtime, cannot only differentially impact their pharmacokinetics and pharmacodynamics but also mediate agonistic/synergetic or antagonistic DDI. To properly manage CVD patients and avoid DDI, it is important that clinicians have sufficient knowledge of their multiple risk factors, i.e., age, gender, and life style elements (like diet, smoking, psychological stress, and alcohol consumption), and comorbidities, such as diabetes, hypertension, dyslipidemia, and depression, and the potential interactions between genetic or epigenetic background of their prescribed therapeutics.

Clinical risk factors and predictive score for the non-dipper profile in hypertensive patients: a case-control study

Background

Night-time BP, especially non-dipper, is a stronger predictor of adverse cardiovascular outcomes. Ambulatory blood pressure monitoring (ABPM) is a gold standard for the detection of non-dippers but it often is unavailable and expensive. This study aims to determine clinical risk factors that predict non-dipper.

Methods

An exploratory traditional case-control study, exclusive sampling of control was conducted from January 2013 to September 2018 to explore clinical risk factors associated with non-dippers in hypertensive patients. Subgroup analysis was performed in each treated and untreated hypertensive patient. The parsimonious predictive score for non-dippers was constructed.

Results

The study included 208 hypertensive patients receiving 24 h ABPM. There were 104 dippers and 104 non-dippers. Significant clinical risk factors associated with non-dippers were the age of > 65 years, average office diastolic blood pressure (DBP), and fasting plasma glucose of > 5.6 mmol/L. Results of subgroup analysis showed that dyslipidemia, history of coronary artery disease, use of angiotensin-converting enzyme inhibitors (ACEIs) and direct vasodilators, average office DBP, and serum uric acid were associated with non-dippers in treated hypertensive patients, however, there were no risk factors associated with non-dippers in the untreated group. The predictive score for non-dippers in treated group included average office DBP, dyslipidemia, serum uric acid, male, calcium channel blockers and ACEIs use. The area under Receiver Operating Characteristic (AuROC) was 0.723. A cut-off point which was > 0.0701 and prevalence of non-dippers of 46%, this score had a sensitivity of 77.4%, specificity of 65.6%, positive predictive value (PPV) of 66.1%, and negative predictive value (NPV) of 79.6%. For untreated group, age, hemoglobin and body mass index were included in the predictive model. AuROC was 0.74. There was a sensitivity of 51.9%, specificity of 91.2%, PPV of 82.4%, and NPV of 70.5% at the cut-off point of > 0.357, and prevalence of 44%.

Conclusion

There were several significant clinical risk factors associated with non-dippers in treated hypertensive patients. The predictive score might be useful for the detection of non-dippers; however, it cannot replace ABPM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40885-021-00180-4.

Systematic review investigating the relationship between autism spectrum disorder and metabolic dysfunction

The objective of this systematic review is to examine metabolic dysfunction, specifically metabolic syndrome and its components, as well as type 2 diabetes mellitus (T2DM) as it relates to individuals with a diagnosis of Autism Spectrum Disorder (ASD). We searched PubMed, Embase, Cochrane, PsychInfo, and Scopus from January 1, 1998 to October 12, 2018 for English, peer-reviewed, original articles containing adult and pediatric populations with any form of ASD and metabolic dysfunction, including T2DM, hyperglycemia, hypertension, dyslipidemia, or central obesity. Exclusion criteria included studies without ASD-specific results, basic science research, review papers, case studies, and medication clinical trials. Eight studies were included in this review, with a total of 70,503 participants with ASD and 2,281,891 in comparison groups. Within ASD populations, higher prevalence for metabolic syndrome components hyperglycemia, hypertension, and dyslipidemia were observed, as well as increased incidence and prevalence of T2DM. However, heterogeneity of study definitions and measurements should be noted. While there is evidence of increased prevalence of T2DM, hyperglycemia, hypertension, and dyslipidemia for those with ASD, the relationship is poorly understood. There is also lack of research investigating central obesity and risk of metabolic syndrome as a diagnosis. More research addressing these gaps is warranted to evaluate the risk of metabolic dysfunction in populations with ASD.

Effects of Experimental Sleep Restriction on Ambulatory and Sleep Blood Pressure in Healthy Young Adults: A Randomized Crossover Study

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High prevalence of non-dipping patterns among Black Africans with uncontrolled hypertension: a secondary analysis of the CREOLE trial

BACKGROUND

Dipping of blood pressure (BP) at night is a normal physiological phenomenon. However, a non-dipping pattern is associated with hypertension mediated organ damage, secondary forms of hypertension and poorer long-term outcome. Identifying a non-dipping pattern may be useful in assessing risk, aiding the decision to investigate for secondary causes, initiating treatment, assisting decisions on choice and timing of antihypertensive therapy, and intensifying salt restriction.

OBJECTIVES

To estimate the prevalence and factors associated with non-dipping pattern and determine the effect of 6 months of three antihypertensive regimens on the dipping pattern among Black African hypertensive patients.

METHODS

This was a secondary analysis of the CREOLE Study which was a randomized, single blind, three-group trial conducted in 10 sites in 6 Sub-Saharan African countries. The participants were 721 Black African patients, aged between 30 and 79 years, with uncontrolled hypertension and a baseline 24-h ambulatory blood pressure monitoring (ABPM). Dipping was calculated from the average day and average night systolic blood pressure measures.

RESULTS

The prevalence of non-dipping pattern was 78% (564 of 721). Factors that were independently associated with non-dipping were: serum sodium > 140 mmol/l (OR = 1.72, 95% CI 1.17-2.51, p-value 0.005), a higher office systolic BP (OR = 1.03, 95% CI 1.01-1.05, p-value 0.003) and a lower office diastolic BP (OR = 0.97, 95% CI 0.95-0.99, p-value 0.03). Treatment allocation did not change dipping status at 6 months (McNemar's Chi2 0.71, p-value 0.40).

CONCLUSION

There was a high prevalence of non-dipping among Black Africans with uncontrolled hypertension. ABPM should be considered more routinely in Black Africans with uncontrolled hypertension, if resources permit, to help personalise therapy. Further research is needed to understand the mechanisms and causes of non-dipping pattern and if targeting night-time BP improves clinical outcomes. Trial registration ClinicalTrials.gov (NCT02742467).

Guidelines for the design and conduct of human clinical trials on ingestion-time differences - chronopharmacology and chronotherapy - of hypertension medications

Current hypertension guidelines fail to provide a recommendation on when-to-treat, thus disregarding relevant circadian rhythms that regulate blood pressure (BP) level and 24 h patterning and medication pharmacokinetics and pharmacodynamics. The ideal purpose of ingestion-time (chronopharmacology, i.e. biological rhythm-dependent effects on the kinetics and dynamics of medications, and chronotherapy, i.e. the timing of pharmaceutical and other treatments to optimize efficacy and safety) trials should be to explore the potential impact of endogenous circadian rhythms on the effects of medications. Such investigations and outcome trials mandate adherence to the basic standards of human chronobiology research. In-depth review of the more than 150 human hypertension pharmacology and therapeutic trials published since 1974 that address the differential impact of upon-waking/morning versus at-bedtime/evening schedule of treatment reveals diverse protocols of sometimes suboptimal or defective design and conduct. Many have been "time-of-day," i.e. morning versus evening, rather than circadian-time-based, and some relied on wake-time office BP rather than around-the-clock ambulatory BP measurements (ABPM). Additionally, most past studies have been of too small sample size and thus statistically underpowered. As of yet, there has been no consensual agreement on the proper design, methods and conduct of such trials. This Position Statement recommends ingestion-time hypertension trials to follow minimum guidelines: (i) Recruitment of participants should be restricted to hypertensive individuals diagnosed according to ABPM diagnostic thresholds and of a comparable activity/sleep routine. (ii) Tested treatment-times should be selected according to internal biological time, expressed by the awakening and bed times of the sleep/wake cycle. (iii) ABPM should be the primary or sole method of BP assessment. (iv) The minimum-required features for analysis of the ABPM-determined 24 h BP pattern ought to be the asleep (not "nighttime") BP mean and sleep-time relative BP decline, calculated in reference to the activity/rest cycle per individual. (v) ABPM-obtained BP means should be derived by the so-called adjusted calculation procedure, not by inaccurate arithmetic averages. (vi) ABPM should be performed with validated and calibrated devices at least hourly throughout two or more consecutive 24 h periods (48 h in total) to achieve the highest reproducibility of mean wake-time, sleep-time and 48 h BP values plus the reliable classification of dipping status. (vii) Calculation of minimum required sample size in adherence with proper statistical methods must be provided. (viii) Hypertension chronopharmacology and chronotherapy trials should preferably be randomized double-blind, randomized open-label with blinded-endpoint, or crossover in design, the latter with sufficient washout period between tested treatment-time regimens.

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.

New perspectives on the definition, diagnosis, and treatment of true arterial hypertension

INTRODUCTION

Office blood pressure measurements (OBPM), still used today for diagnosis and management of hypertension, fail to reveal clinically important features of the mostly predictable blood pressure (BP) 24 h pattern, and lead to >45% of individuals being misclassified. Current hypertension guidelines do not provide recommendation on when-to-treat, despite multiple prospective clinical trials documenting improved normalization of 24 h BP pattern and significant reduction in cardiovascular disease (CVD) events when hypertension medications are ingested at bedtime rather than upon waking.

AREAS COVERED

In this review, the authors discuss current evidence on the: (i) most relevant attributes of the 24 h BP pattern deterministic of CVD risk; (ii) asleep systolic BP (SBP) mean as the most significant therapeutic target for CVD risk reduction; (iii) ingestion-time differences in pharmacodynamics of BP-lowering medications as reported with high consistency in multiple clinical trials; and (iv) enhanced prevention of CVD events achieved by bedtime hypertension chronotherapy.

EXPERT OPINION

Several prospective trials consistently document asleep SBP mean and sleep-time relative SBP decline (dipping) constitute highly significant CVD risk factors, independent of OBPM. Bedtime, compared to customary upon-waking, hypertension chronotherapy reduces risk of major CVD events. Collectively, these findings call for new definition of true hypertension and, accordingly, its proper diagnosis and management.

Effects of obstructive sleep apnea on endogenous circadian rhythms assessed during relaxed wakefulness; an exploratory analysis

Obstructive sleep apnea (OSA) is associated with hypertension, cardiovascular disease, and a change in the 24 h pattern of adverse cardiovascular events and mortality. Adverse cardiovascular events occur more frequently in the middle of the night in people with OSA, earlier than the morning prevalence of these events in the general population. It is unknown if these changes are associated with a change in the underlying circadian rhythms, independent of behaviors such as sleep, physical activity, and meal intake. In this exploratory analysis, we studied the endogenous circadian rhythms of blood pressure, heart rate, melatonin and cortisol in 11 participants (48 ± 4 years; seven with OSA) throughout a 5 day study that was originally designed to examine circadian characteristics of obstructive apnea events. After a baseline night, participants completed 10 recurring 5 h 20 min behavioral cycles divided evenly into standardized sleep and wake periods. Blood pressure and heart rate were recorded in a relaxed semirecumbent posture 15 minutes after each scheduled wake time. Salivary melatonin and cortisol concentrations were measured at 1-1.5 h intervals during wakefulness. Mixed-model cosinor analyses were performed to determine the rhythmicity of all variables with respect to external time and separately to circadian phases (aligned to the dim light melatonin onset, DLMO). The circadian rhythm of blood pressure peaked much later in OSA compared to control participants (group × circadian phase, p < .05); there was also a trend toward a slightly delayed cortisol rhythm in the OSA group. Rhythms of heart rate and melatonin did not differ between the groups. In this exploratory analysis, OSA appears to be associated with a phase change (relative to DLMO) in the endogenous circadian rhythm of blood pressure during relaxed wakefulness, independent of common daily behaviors.

A computational intelligence tool for the detection of hypertension using empirical mode decomposition

Hypertension (HPT), also known as high blood pressure, is a precursor to heart, brain or kidney diseases. Some symptoms of HPT include headaches, dizziness and fainting. The potential diagnosis of masked hypertension is of specific interest in this study. In masked hypertension (MHPT), the instantaneous blood pressure appears normal, but the 24-h ambulatory blood pressure is abnormal. Hence patients with MHPT are difficult to identify and thus remain untreated or are treated insufficiently. Hence, a computational intelligence tool (CIT) using electrocardiograms (ECG) signals for HPT and possible MHPT detection is proposed in this work. Empirical mode decomposition (EMD) is employed to decompose the pre-processed signals up to five levels. Nonlinear features are extracted from the five intrinsic mode functions (IMFs) thereafter. Student's t-test is subsequently applied to select a set of highly discriminatory features. This feature set is then input to various classifiers, in which, the best accuracy of 97.70% is yielded by the k-nearest neighbor (k-NN) classifier. The developed tool is evaluated by the 10-fold cross validation technique. Our findings suggest that the developed system is useful for diagnostic computational intelligence tool in hospital settings, and that it enables the automatic classification of HPT versus normal ECG signals.

Risk of new-onset metabolic syndrome associated with white-coat and masked hypertension: data from a general population

AIM

In the Pressioni Arteriose Monitorate e Loro Associazioni (PAMELA) study, clinical and metabolic variables as well as office, home and ambulatory blood pressure (BP) values were simultaneously measured at baseline and after a 10-year follow-up. The study design allowed us to assess the value of selective and combined elevation of different BP phenotypes in predicting new-onset metabolic syndrome (MetS).

METHODS

The present analysis included 1182 participants without MetS at baseline, as defined by the APT III criteria. On the basis of office, 24-h ambulatory BP and home values, participants were divided into four groups: normal, white-coat hypertension (WCH), masked hypertension and sustained hypertension.

RESULTS

Compared with participants with in-office and out-of-office normal BP, a greater incidence of new-onset age-adjusted and sex-adjusted MetS was observed in WCH (OR = 1.75, CI 1.01-3.04, P = 0.0046), masked hypertension (OR = 2.58, CI 1.26-5.30; P = 0.009) and sustained hypertension (OR = 2.14, CI 1.20-3.79, P = 0.009)) when out-of-office BP was defined by ambulatory criteria. This was not the case when out-of-office BP was defined by home criteria, as only the WCH group showed a greater risk (OR 2.16, CI 1.28-3.63, P = 0.003). Similar findings were obtained for single components of the MetS such as abdominal obesity and hyperglycemia.

CONCLUSION

Our study provides evidence that either isolated or combined BP elevations identified by office/ambulatory measurements, carry an increased risk of new-onset MetS, whereas, only WCH is associated with a greater risk of incident MetS whenever BP phenotypes are identified by office/home measurements. In a clinical perspective, a comprehensive evaluation of BP status based on office/ambulatory measurements may improve diagnosis of new-onset MetS and activate measures for its prevention.

When Office Blood Pressure Is Not Enough: The Case of Masked Hypertension

An increasing attention has been devoted in the last two decades to masked hypertension (MH), a condition characterized by the fact that classification of a normal blood pressure (BP) status by office measurements is not confirmed by home and/or ambulatory BP monitoring (ABPM). MH definition (i.e., normal office BP, but high out-of-office BP) should be restricted to untreated subjects (true MH) whereas masked uncontrolled hypertension (MUCH) reserved to treated patients previously classified as hypertensives, presenting normal office BP and high ABPM or home values. Both MH and MUCH are associated with metabolic alterations, comorbidities, and hypertension-mediated organ damage (HMOD). Furthermore, the risk of cardiovascular events related to these conditions has been shown to be close or greater than that of sustained hypertension. This review discusses available evidence about MH and MUCH by focusing on its prevalence, clinical correlates, association with HMOD, prognostic significance, and their therapeutic implications.

Chronobiology in nephrology: the influence of circadian rhythms on renal handling of drugs and renal disease treatment

INTRODUCTION

Chronobiology studies the phenomenon of rhythmicity in living organisms. The circadian rhythms are genetically determined and regulated by external synchronizers (the daylight cycle). Several biological processes involved in the pharmacokinetics and pharmacodynamics of drugs are subjected to circadian variations. Chronopharmacology studies how biological rhythms influence pharmacokinetics, pharmacodynamics, and toxicity, and determines whether time-of-day administration modifies the pharmacological characteristics of the drug. Chronotherapy applies chronopharmacological studies to clinical treatments, determining the best biological time for dosing: when the beneficial effects are maximal and the incidence and/or intensity of related side effects and toxicity are minimal. Most water-soluble drugs or drug metabolites are eliminated by urine through the kidney. The rate of drug clearance in the urine depends on several intrinsic variables related to renal function including renal blood flow, glomerular filtration rate, the ability of the kidney to reabsorb or to secrete drugs, urine flow, and urine pH, which influences the degree of urine acidification. Curiously, all these variables present a circadian behavior in different mammalian models.

CONCLUSION

The circadian rhythms have influence in the renal physiology, pathophysiology, and pharmacology, and these data should be taken into account in clinical nephrology practice.

Hydra, a Computer-Based Platform for Aiding Clinicians in Cardiovascular Analysis and Diagnosis

Cardiovascular diseases (CVDs) are the leading cause of death throughout the world. The total risk of developing CVD is determined by the combined effect of different cardiovascular risk factors (e.g., diabetes, raised blood pressure, unhealthy diet, tobacco use, stress, etc.) that commonly coexist and act multiplicatively. Most CVDs can be prevented by an early identification of the highest risk factors and an appropriate treatment. The stratification of cardiovascular risk factors involves a wide range of parameters and tests that specialists use in their clinical practice. In addition to cardiovascular (CV) risk stratification, ambulatory blood pressure monitoring (ABPM) also provides relevant information for diagnostic and treatment purposes. This work presents a list of protocols based on the Hydra platform, a web-based system for clinical decision support which incorporates a set of functionalities and services that are required for complete cardiovascular analysis, risk assessment, early diagnosis, treatment and monitoring of patients over time. The program includes tools for inputting and managing comprehensive patient data, organized into different checkups to track the evolution over time. It also has a risk stratification tool to compute a CV risk factor based upon several risk stratification tables of reference. Additionally, the program includes a tool that incorporates ABPM analysis and allows the extraction of valuable information by monitoring blood pressure over a specific period of time. Finally, the reporting service summarizes the most relevant information in a set of reports that aid clinicians in their clinical decision-making process.

The value of ABPM and subclinical target organ damage parameters in diagnosis of resistant hypertension

INTRODUCTION

We aimed to assess the effectiveness of ambulatory blood pressure monitoring (ABPM) and subclinical target organ damage parameters for diagnosis of resistant hypertension (RH).

METHODS

We assessed demographic and anthropometric variables, the incidence of cardiovascular events and subclinical target organ damage (n=112). We also studied the relationship between these variables and the ABPM results.

RESULTS

Of the 112 patients referred from primary care with a diagnosis of RH, 69 (61.6%) were confirmed by ABPM. We found statistically significant differences (P<.001) between patients with RH and pseudo-resistant hypertension in the appearance of subclinical target organ damage. A percentage of 84 of the patients had microalbuminuria: 66.25±30.7mg/dl); 44.9% had stage 3 chronic kidney disease: the average glomerular filtration was 59ml/min/1.73m²; and 56.5% had left ventricular hypertrophy on echocardiography. Fundoscopy revealed that 64% of the patients had hypertensive retinopathy. Three variables were associated with an increased HR risk: microalbuminuria, hypertensive retinopathy and left ventricular hypertrophy (OR 5.7, 6.2 and 11.2, respectively).

CONCLUSIONS

This study shows that the systematic testing for target organ damage, particularly in terms of albuminuria, is a simple and inexpensive tool, with a high predictive value for RH (85%), which could be useful for prioritising patients who need ABPM.

Blood pressure and heart rate variability are linked with hyperphosphatemia in chronic kidney disease patients

Hyperphosphatemia is a common complication of chronic kidney disease (CKD) and is associated with cardiovascular disease (CVD), which has contributed to an increase in mortality of CKD patients. The onset of CVD often varies by time-of-day. Acute myocardial infarction or ventricular arrhythmia occurs most frequently during early morning. Blood pressure (BP) and heart rate circadian rhythms account for the diurnal variations in CVD. Preservation of normal circadian time structure from the cardiomyocyte level to the whole organ system is essential for cardiovascular health and CVD prevention. Independent risk factors, such as reduced heart rate variability (HRV) and increased BP variability (BPV), are particularly prevalent in patients with CKD. Analysis of HRV is an important clinical tool for characterizing cardiac autonomic status, and reduced HRV has prognostic significance for various types of CVD. Circadian BP rhythms are classified as extreme dipper, dipper, non-dipper or riser. It has been reported that nocturnal riser BP pattern contributes to cardiovascular threats. Previous studies have indicated that the circadian rhythm of serum phosphate in CKD patients is consistent with the general population, with the highest diurnal value observed in the early morning hours, followed by a progressive decrease to the lowest value of the day, which occurs around 11:00 am. Rhythm abnormalities have become the main therapeutic target for treating CVD in CKD patients. It has been reported that high levels of serum phosphate are associated with reduced HRV and increased BPV in CKD patients. However, the mechanisms related to interactions between hyperphosphatemia, HRV and BPV have not been fully elucidated. This review focuses on the evidence and discusses the potential mechanisms related to the effects of hyperphosphatemia on HRV and BPV.

Hypertension: New perspective on its definition and clinical management by bedtime therapy substantially reduces cardiovascular disease risk

Diagnosis of hypertension-elevated blood pressure (BP) associated with increased cardiovascular disease (CVD) risk-and its management for decades have been based primarily on single time-of-day office BP measurements (OBPM) assumed representative of systolic (SBP) and diastolic BP (DBP) during the entire 24-hours span. Around-the-clock ambulatory blood pressure monitoring (ABPM), however, reveals BP undergoes 24-hours patterning characterized in normotensives and uncomplicated hypertensives by striking morning-time rise, 2 daytime peaks-one ~2-3 hours after awakening and the other early evening, small midafternoon nadir and 10-20% decline (BP dipping) in the asleep BP mean relative to the wake-time BP mean. A growing number of outcome trials substantiate correlation between BP and target organ damage, vascular and other risks is greater for the ABPM-derived asleep BP mean, independent and stronger predictor of CVD risk, than daytime OBPM or ABPM-derived awake BP. Additionally, bedtime hypertension chronotherapy, that is, ingestion of ≥1 conventional hypertension medications at bedtime to achieve efficient attenuation of asleep BP, better reduces total CVD events by 61% and major events (CVD death, myocardial infarction, ischaemic and haemorrhagic stroke) by 67%-even in more vulnerable chronic kidney disease, diabetes and resistant hypertension patients-than customary on-awaking therapy that targets wake-time BP. Such findings of around-the-clock ABPM and bedtime hypertension outcome trials, consistently indicating greater importance of asleep BP than daytime OBPM or ambulatory awake BP, call for a new definition of true arterial hypertension plus modern approaches for its diagnosis and management.

Clinical Conditions and Predictive Markers of Non-Dipper Profile in Hypertensive Patients

Hypertension remains one of the primary causes of premature cardiovascular mortality representing a major independent risk factor.

The importance of ambulatory blood pressure monitoring in clinical evaluation of hypertensive patients, beyond diagnosis, is the identification of circadian dipping/non-dipping profile. The non-dipper pattern in hypertensive and normotensive patients is associated with significant target organ damage and worse outcomes, as an increased cardiovascular risk condition. Non-dipping pattern has been found to be associated with specific clinical conditions. Obesity, diabetes mellitus, metabolic syndrome, obstructive sleep apnea syndrome, chronic kidney disease, autonomic and baroreflex dysfunctions, salt sensitivity, hormonal changes, gender and age were extensively studied. Research efforts are focused on recognizing and exploring predictive markers of abnormal blood pressure circadian pattern. Previous studies acknowledge that red cell distribution width, mean platelet volume, fibrinogen level, C-reactive protein, serum uric acid and gamma-glutamyltransferase, are independently significant and positive associated to non-dipping pattern. Moreover, research on new biomarkers are conducted: Chitinase 3-Like-Protein 1, atrial and B-type natriuretic peptide, brain-derived neurotrophic factor, chemerin, sphingomyelin and the G972R polymorphism of the insulin receptor substrate-1 gene. This review summarizes the current knowledge of different clinical conditions and biomarkers associated with the non-dipper profile in hypertensive patients.

White-Coat Hypertension: the Neglected Subgroup in Hypertension

The clinical prognostic importance of white coat hypertension (WCH), that is, the clinical condition characterized by an increase of office but a normal ambulatory or home blood pressure (BP) is since a long time matter of considerable debate. WCH accounts for a consistent portion of hypertensive patients (up to 30–40%), particularly when hypertension is mild or age is more advanced. Although scanty and inconsistent information is available on the response of office and out-office BP to antihypertensive treatment and the cardiovascular (CV) protection provided by treatment, an increasing body of evidence focusing on the association of WCH with CV risk factors, subclinical cardiac and extra-cardiac organ damage and, more importantly, with CV events indicates that the risk entailed by this condition is intermediate between true normotension and sustained hypertension. This review will address a number of issues concerning WCH with particular attention to prevalence and clinical correlates, relation with subclinical target organ damage and CV morbidity/mortality, therapeutic perspectives. Several topics covered in this review are based on data acquired over the past 20 years by the Pressioni Arteriose Monitorate E Loro Associazioni (PAMELA) study, a longitudinal survey performed by our group on the general population living in the surroundings of Milan area in the north part of Italy.

Evaluation of tolerance to ambulatory blood pressure monitoring: Analysis of dipping profile in a large cohort of hypertensive patients

Ambulatory blood pressure monitoring (ABPM) is a helpful tool to comprehensively identify and diagnose arterial hypertension. Moreover, it allows to better identify alterations in the circadian BP profile, as the nocturnal "nondipping" status, characterized by a lack of the physiological 10% night BP reduction and associated with a greater risk of target organ damage. However, ABPM has some limitations such as restricted availability, discomfort, particularly at night, cost implications, and reproducibility.Aim of the study was evaluate if the "nondipping" phenomenon may be related to low degree of tolerance to ABPM. Additionally, to determine whether self-reported events of sleep disorders and nighttime urinations may affect the "nondipping" status.From January 2013 to December 2015, we consecutively evaluated 1046 patients with arterial hypertension, performing ABPM, considering a tolerance index calculated on the basis of the patients' responses to a questionnaire.Thirty-eight out of 1046 patients showed complete lack of tolerance to the instrument during the day, whilst 126 during the night. There were no statistically significant differences in daytime and nighttime values of tolerance to the instrument between "dippers" and "nondippers," between "extreme-dippers" and the remaining patients or between "reverse-dippers" and the remaining patients. There were no statistically significant differences in the number of nocturnal awakenings between the groups. However, we found that the number of awakenings followed by urination was higher in "nondipping" patients and in "reverse-dipping" patients compared to the other groups.We found that the poor tolerance to the instrument does not seem to influence the BP "dipping" phenomenon among hypertensive individuals. Moreover, we think that in the evaluation of the ABPM data, factors, such as nocturnal urination and sleep disorders, need to be carefully taken into account, since may lead to a higher incidence of "nondipping" pattern.

Ambulatory blood pressure monitoring in daily practice

Ambulatory blood pressure monitoring is a useful diagnostic tool that still underutilized by community physicians. It is a cost effective, diagnostic and prognostic tool that had been emphasized by the guidelines.

Do night and around-the-clock firefighters' shift schedules induce deviation in tau from 24 hours of systolic and diastolic blood pressure circadian rhythms?

Systolic (S) and diastolic (D) blood pressures (BP) [SBP and DBP] are circadian rhythmic with period (τ) in healthy persons assumed to be maintained at 24.0h. We tested this assumption in a sample of 30 healthy career (mean >12 yrs) 30-to-46 yr-old male Caucasian French firefighters (FFs) categorized into three groups according to work schedule and duties: Group A - 12 FFs working 12h day, 12h night, and occasionally 24h shifts and whose primary duties are firefighting plus paramedical and road rescue services; Group B - 9 FFs working mostly 12h day and 12h night shifts and whose duties are answering incoming emergency calls and coordinating service vehicle dispatch from fire stations with Group A personnel; Group C - 9 day shift (09:00-17:00h) FFs charged with administrative tasks. SBP and DBP, both in winter and in summer studies of the same FFs, were sampled by ambulatory BP monitoring every 1h between 06:00-23:00h and every 2h between 23:01-05:59h, respectively, their approximate off-duty wake and sleep spans, for 7 consecutive days. Activity (wrist actigraphy) was also sampled at 1-min intervals. Prominent τ of each variable was derived by a power spectrum program written for unequal-interval time series data, and between-group differences in incidence of τ≠24h of FFs were assessed by chi square test. Circadian rhythm disruption (τ≠24h) of either the SBP or DBP rhythm occurred almost exclusively in night and 24h shift FFs of Group A and B, but almost never in day shift FFs of Group C, and it was not associated with altered τ from 24.0h of the circadian activity rhythm. In summer, occurrence of τ≠24 for FFs of Group A and B differed from that for FFs of Group C in SBP (p=0.042) and DBP (p=0.015); no such differences were found in winter (p>0.10). Overall, manifestation of prominent τ≠24h of SBP or DBP time series was greater in summer than winter, 27.6% versus 16.7%, when workload of Group B FFs, i.e. number of incoming emergency telephone calls, and of Group A FFs, i.e. number of dispatches for provision of emergency services, was, respectively, two and fourfold greater and number of 12h night shifts worked by Group B FFs and number of 24h shifts worked by Group A FFs was, respectively, 92% and 25% greater. FFs of the three groups exhibited no winter-summer difference in τ≠24h of SBP or SDP; however, τ≠24h of DBP in Group B FFs was more frequent in summer than winter (p=0.046). Sleep/wake cycle disruption, sleep deprivation, emotional and physical stress, artificial light-at-night, and altered nutrient timings are hypothesized causes of τ≠24h for BP rhythms of affected Groups A and B FFs, but with unknown future health effects.

Bedtime Blood Pressure Chronotherapy Significantly Improves Hypertension Management

Consistent evidence of numerous studies substantiates the asleep blood pressure (BP) mean derived from ambulatory BP monitoring (ABPM) is both an independent and a stronger predictor of cardiovascular disease (CVD) risk than are daytime clinic BP measurements or the ABPM-determined awake or 24-hour BP means. Hence, cost-effective adequate control of sleep-time BP is of marked clinical relevance. Ingestion time, according to circadian rhythms, of hypertension medications of 6 different classes and their combinations significantly improves BP control, particularly sleep-time BP, and reduces adverse effects.

Bedtime Chronotherapy with Conventional Hypertension Medications to Target Increased Asleep Blood Pressure Results in Markedly Better Chronoprevention of Cardiovascular and Other Risks than Customary On-awakening Therapy

The bases for bedtime hypertension chronotherapy (BHCT) as superior chronoprevention against cardiovascular disease (CVD) are: (1) correlation between blood pressure (BP) and various risks is greater for ambulatory BP monitoring (ABPM) than office BP measurements (OBPM); (2) asleep BP mean is a better predictor of CVD risk than ABPM awake and 24-hour means and OBPM; and (3) targeting of asleep BP by BHCT with one or more conventional medications versus usual on-awakening therapy better reduces major and total CVD events. BHCT offers the most cost-effective chronoprevention against adverse CVD outcomes in regular and vulnerable renal, diabetic, and resistant hypertensive patients.

Circadian Periodicity of Ischemic Heart Disease: A Systematic Review of the Literature

The authors performed a MEDLINE search to identify reports, published during the last 20 years, focused on circadian variation of acute myocardial infarction (AMI), and prevalence and the ratios between the number of events per hour during the morning and the other hours of the day were calculated. Despite the optimization of interventional and medical therapy of AMI since the first reports of circadian patterns in AMI occurrence, it was found that such a pattern still exists and that AMI happens most frequently in the morning hours.

Microarray Analysis Reveals Increased Expression of Matrix Metalloproteases and Cytokines of Interleukin-20 Subfamily in the Kidneys of Neonate Rats Underwent Unilateral Ureteral Obstruction: A Potential Role of IL-24 in the Regulation of Inflammation and Tissue Remodeling

BACKGROUND/AIMS

Congenital obstructive nephropathy (CON) is the main cause of pediatric chronic kidney diseases leading to renal fibrosis. High morbidity and limited treatment opportunities of CON urge the better understanding of the underlying molecular mechanisms.

METHODS

To identify the differentially expressed genes, microarray analysis was performed on the kidney samples of neonatal rats underwent unilateral ureteral obstruction (UUO). Microarray results were then validated by real-time RT-PCR and bioinformatics analysis was carried out to identify the relevant genes, functional groups and pathways involved in the pathomechanism of CON. Renal expression of matrix metalloproteinase (MMP)-12 and interleukin (IL)-24 were evaluated by real-time RT-PCR, flow cytometry and immunohistochemical analysis. Effect of the main profibrotic factors on the expression of MMP-12 and IL-24 was investigated on HK-2 and HEK-293 cell lines. Finally, the effect of IL-24 treatment on the expression of pro-inflammatory cytokines and MMPs were tested in vitro.

RESULTS

Microarray analysis revealed 880 transcripts showing >2.0-fold change following UUO, enriched mainly in immune response related processes. The most up-regulated genes were MMPs and members of IL-20 cytokine subfamily, including MMP-3, MMP-7, MMP-12, IL-19 and IL-24. We found that while TGF-β treatment inhibits the expression of MMP-12 and IL-24, H2O2 or PDGF-B treatment induce the epithelial expression of MMP-12. We demonstrated that IL-24 treatment decreases the expression of IL-6 and MMP-3 in the renal epithelial cells.

CONCLUSIONS

This study provides an extensive view of UUO induced changes in the gene expression profile of the developing kidney and describes novel molecules, which may play significant role in the pathomechanism of CON.

Report and Research Agenda of the American Geriatrics Society and National Institute on Aging Bedside-to-Bench Conference on Sleep, Circadian Rhythms, and Aging: New Avenues for Improving Brain Health, Physical Health, and Functioning

The American Geriatrics Society, with support from the National Institute on Aging and other funders, held its eighth Bedside-to-Bench research conference, entitled "Sleep, Circadian Rhythms, and Aging: New Avenues for Improving Brain Health, Physical Health and Functioning," October 4 to 6, 2015, in Bethesda, Maryland. Part of a conference series addressing three common geriatric syndromes-delirium, sleep and circadian rhythm (SCR) disturbance, and voiding dysfunction-the series highlighted relationships and pertinent clinical and pathophysiological commonalities between these three geriatric syndromes. The conference provided a forum for discussing current sleep, circadian rhythm, and aging research; identifying gaps in knowledge; and developing a research agenda to inform future investigative efforts. The conference also promoted networking among developing researchers, leaders in the field of SCR and aging, and National Institutes of Health program personnel.

Acute Sildenafil Use Reduces 24-Hour Blood Pressure Levels in Patients With Resistant Hypertension: A Placebo-Controlled, Crossover Trial

The authors previously demonstrated that acute administration of sildenafil-a phosphodiesterase 5 (PDE5) inhibitor-improves hemodynamic parameters in patients with resistant hypertensive (RH), but its effect on ambulatory blood pressure monitoring (ABPM) is unknown. This interventional, nonrandomized, single-blinded, placebo-controlled, crossover trial included 26 patients with RH. A dose of sildenafil (187.5mg) was given, and after a washout period of 14 days the patients received a single oral dose of placebo and the protocol was repeated. The patients underwent 24-hour ABPM recordings the day before and immediately after the protocols. The reduction of systolic (-8.8±1.4 vs 1.3±1.2 mm Hg, P=.02), diastolic (-5.3±3.3 vs 1.8±1.1 mm Hg, P=.03), and mean (-7.9±3.6 vs 0.8±0.9 mm Hg, P=.01) 24-hour BP were found after the use of sildenafil compared with placebo. Improvement in daytime BP levels was also observed (systolic -6.0±4.7 vs 4.4±1.5 mm Hg [P=.02] and mean -4.8±3.9 vs 3.5±1.4 mm Hg [P=.02] for sildenafil vs placebo, respectively). Considering its antihypertensive effect, sildenafil may represent a therapeutic option for RH treatment.

Sleep-time ambulatory blood pressure as a prognostic marker of vascular and other risks and therapeutic target for prevention by hypertension chronotherapy: Rationale and design of the Hygia Project

This article describes the rationale, objectives, design and conduct of the ambulatory blood pressure monitoring (ABPM)-based Hygia Project. Given the substantial evidence of the significantly better prognostic value of ABPM compared to clinic BP measurements, several international guidelines now propose ABPM as a requirement to confirm the office diagnosis of hypertension. Nonetheless, all previous ABPM outcome investigations, except the Monitorización Ambulatoria para Predicción de Eventos Cardiovasculares study (MAPEC) study, relied upon only a single, low-reproducible 24 h ABPM assessment per participant done at study inclusion, thus precluding the opportunity to explore the potential reduction in cardiovascular disease (CVD) risk associated with modification of prognostic ABPM-derived parameters by hypertension therapy. The findings of the single-center MAPEC study, based upon periodic systematic 48 h ABPM evaluation of all participants during a median follow-up of 5.6 years, constitute the first proof-of-concept evidence that the progressive reduction of the asleep systolic blood pressure (SBP) mean and correction of the sleep-time relative SBP decline toward the normal dipper BP profile, most efficiently accomplished by a bedtime hypertension treatment strategy, best attenuates the risk of CVD, stroke and development of new-onset diabetes. The Hygia Project, primarily designed to extend the use of ABPM in primary care as a requirement for diagnosis of hypertension, evaluation of response to treatment and individualized assessment of CVD and other risks, is a research network presently composed of 40 clinical sites and 292 investigators. Its main objectives are to (i) investigate whether specific treatment-induced changes in ABPM-derived parameters reduce risk of CVD events, stroke, new-onset diabetes and/or development of chronic kidney disease (CKD); and (ii) test the hypothesis that bedtime chronotherapy entailing the entire daily dose of ≥1 conventional hypertension medications exerts better ambulatory BP control and CVD, metabolic and renal risk reduction than all such medications ingested in the morning upon awakening. Between 2007 and 2015, investigators recruited 18 078 persons [9769 men/8309 women, 59.1 ± 14.3 years of age (mean ± SD)], including 15 764 with hypertension according to ABPM criteria as participants in the prospective randomized chronotherapy trial. The initial evaluation includes 48 h ABPM, detailed medical history and screening laboratory blood and urine tests. The same evaluation procedure is scheduled annually, or more frequently when treatment adjustment is required for proper ambulatory BP control, targeting a median follow-up of >5 years. The primary CVD outcome end point is the composite of CVD death, myocardial infarction, coronary revascularization, heart failure, ischemic stroke and hemorrhagic stroke. The independent Hygia Project Events Committee periodically evaluates blinded clinical reports to ascertain and certify every documented event. Beyond the potential findings resulting from testing the main hypotheses, the Hygia Project has already demonstrated, as proof of concept, that the routine diagnosis of hypertension and individualized assessment of CVD and other risks by ABPM, as currently recommended, is fully viable in the primary care setting, where most people with either hypertension, dyslipidemia, type 2 diabetes or CKD receive routine medical attention.

Blood pressure reverse dipping may associate with stable coronary artery disease in patients with essential hypertension: a cross-sectional study

The dipping variations of circadian blood pressure (BP) correlate closely with target-organ damages and cardiovascular events. The aim of this study was to investigate the relationship between BP reverse dipping and the prevalence of stable coronary artery disease (sCAD) in hypertensive patients. Clinical data and the results of 24-hour ambulatory BP monitoring (ABPM) were obtained from 718 hypertensive patients (390 males, mean age 59.6 ± 13.8 years) in a single centre in Northern China. Reverse dipping pattern was defined as nocturnal systolic BP (SBP) was higher than daytime SBP. A logistic regression model was applied to explore the independent risk factors of sCAD. The patients with BP reverse dipping accounted for 31.5% in sCAD group and 19.5% in control group (P < 0.05). In multivariate analysis, BP reverse dipping remained significantly associated with the prevalence of sCAD (Odds ratio [OR], 1.772; p = 0.027). Furthermore, the circadian decline rate of SBP was independently associated with sCAD (OR, 0.975; p = 0.043). The hypertensive patients with reverse BP dipping were found to be more frequently suffering from sCAD. BP reverse dipping examined with 24-hour ABPM may indicate sCAD.

Chronotherapy with conventional blood pressure medications improves management of hypertension and reduces cardiovascular and stroke risks

Correlation between blood pressure (BP) and target organ damage, vascular risk and long-term patient prognosis is greater for measurements derived from around-the-clock ambulatory BP monitoring than in-clinic daytime ones. Numerous studies consistently substantiate the asleep BP mean is both an independent and a much better predictor of cardiovascular disease (CVD) risk than either the awake or 24 h means. Sleep-time hypertension is much more prevalent than suspected, not only in patients with sleep disorders, but also among those who are elderly or have type 2 diabetes, chronic kidney disease or resistant hypertension. Hence, cost-effective adequate control of sleep-time BP is of marked clinical relevance. Ingestion time, according to circadian rhythms, of hypertension medications of six different classes and their combinations significantly affects BP control, particularly sleep-time BP, and adverse effects. For example, because the high-amplitude circadian rhythm of the renin-angiotensin-aldosterone system activates during nighttime sleep, bedtime vs. morning ingestion of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers better reduces the asleep BP mean, with additional benefit, independent of medication terminal half-life, of converting the 24 h BP profile into more normal dipper patterning. The MAPEC (Monitorización Ambulatoria para Predicción de Eventos Cardiovasculares) study, first prospective randomized treatment-time investigation designed to test the worthiness of bedtime chronotherapy with ⩾1 conventional hypertension medications so as to specifically target attenuation of asleep BP, demonstrated, relative to conventional morning therapy, 61% reduction of total CVD events and 67% decrease of major CVD events, that is, CVD death, myocardial infarction, and ischemic and hemorrhagic stroke. The MAPEC study, along with other earlier conducted less refined trials, documents the asleep BP mean is the most significant prognostic marker of CVD morbidity and mortality; moreover, it substantiates attenuation of the asleep BP mean by a bedtime hypertension treatment strategy entailing the entire daily dose of ⩾1 hypertension medications significantly reduces CVD risk in both general and more vulnerable hypertensive patients, that is, those diagnosed with chronic kidney disease, diabetes and resistant hypertension.