Bedtime administration of long-acting antihypertensive drugs restores normal nocturnal blood pressure fall in nondippers with essential hypertension. Clin Exp Nephrol. 2009;13:467-472. [PMID: 19449087 DOI: 10.1007/s10157-009-0184-4]

Concurrent Aerobic Plus Resistance Training Elicits Different Effects on Short-Term Blood Pressure Variability of Hypertensive Patients in Relation to Their Nocturnal Blood Pressure Pattern

Background and Objectives: The purpose of this study was to investigate the effects of a 12-week concurrent training (CT) (i.e., aerobic plus resistance exercise) on short–term blood pressure variability (BPV) and BP values in hypertensive patients with non-dippper BP nocturnal pattern and underlying coronary artery disease. Material and Methods: The study included 72 consecutive patients who were divided into two groups according to the nocturnal BP pattern: dipping pattern (33 pts) and non-dipping (39 pts). Before starting CT and at 12 weeks, patients underwent the six minute walk test, ergometric test, assessment of 1-repetiton maximum (1 RM), and 24/h BP monitoring (24-h ABPM). Results: After CT, exercise capacity increased in both groups in a similar fashion. Twenty-four/h systolic BPV and daytime systolic BPV decreased significantly in the dipping group while they were unchanged in the non-dipping group (between groups changes: −1.0 ± 0.4 mmHg and −1.3 ± 0.9 mmHg; p = 0.02 and p = 0.006, respectively). Twenty-four/h systolic BP and daytime systolic BP decreased significantly in the dipping group while they were unchanged in the non-dipping group (between groups changes: −7.1 ± 2.6 mmHg and −7.8 ± 2.4 mmHg; p = 0.004 and p = 0.002, respectively). Nighttime systolic BP and BPV was unchanged in both groups. Twenty-four/h diastolic BP presented small but not significant changes in both groups. Conclusions: The effects of CT on BPV and BP were blunted in hypertensive subjects with a non-dipping BP pattern.

Dosing Time Matters? Nighttime vs. Daytime Administration of Nifedipine Gastrointestinal Therapeutic System (GITS) or Amlodipine on Non-dipper Hypertension: A Randomized Controlled Trial of NARRAS

Background: Non-dipper hypertension is often characterized by a blunted decrease of nocturnal blood pressure (BP) and is associated with increased risk of target organ damage and cardiovascular (CV) events, while the optimal treatment strategy is yet to be established. This trial was designed to evaluate whether nocturnal BP reduction and arterial stiffness improvement differ from antihypertensive agents and time of administration. Methods: Young and middle-aged adults (18-65 years) with non-dipper hypertension were randomly assigned to nifedipine GITS (gastrointestinal therapeutic system) 30 mg or amlodipine besylate 5 mg once daily for 8 weeks, either taken in the morning or at night. Dose was doubled at 4-week if BP is not at goal. Twenty-four hour ambulatory BP monitoring (ABPM) and arterial stiffness were evaluated before and after 8 weeks of pharmacotherapy. The primary efficacy measure was the average nighttime systolic BP reduction. Results: A total of 98 non-dipper hypertensive patients (mean age 46.3 years) were randomized during Dec, 2016 and Dec, 2020, of whom 72 (73%) patients completed all ABPM and follow-up evaluations. Nighttime systolic BP significantly reduced at 8 weeks vs. baseline with nifedipine GITS or amlodipine, irrespective of dosing at nighttime (-9.9 vs -9.9 mmHg, P > 0.05) or daytime (-11.5 vs. -10.9 mmHg, P > 0.05). No difference was seen between these two agents, when combining the data of nighttime and daytime dosing together (-10.8 vs. -10.5 mmHg, respectively, P = 0.898). Daytime, 24-h systolic BP, diastolic BP at different time and pulse wave velocity reduced significantly and comparably, and recovery of dipping rhythm were similar among groups. Conclusion: Nighttime dosing of long-acting antihypertensive preparations, nifedipine GITS or amlodipine demonstrated similar effects on nocturnal BP reduction, dipping rhythm restoration and arterial elasticity improvement in younger subjects with non-dipper hypertension. These effects were comparable with morning dosing.

A comparative study for the effects of nifedipine GITS and amlodipine besylate administrated in daytime or at nighttime on recovery of blood pressure rhythm and arterial stiffness in the young and middle-aged subjects with non-dipper hypertension (NARRAS): Design and rationale

INTRODUCTION

Hypertensive patients with a blunted or absent nocturnal blood pressure (BP) drop (non-dipper) are associated with arterial stiffening and additional cardiovascular risk. Non-dipper hypertension is prevalent in young and middle-aged adults; but the optimal antihypertensive strategy remains unclear. There is a need to explore the effects of different antihypertensive agents and time of administration on recovery of dipper rhythm and arterial stiffness in this population.

METHODS AND ANALYSIS

NARRAS is a randomised controlled trial (RCT), designed to evaluate the effects of long-acting antihypertensive agents administrated in daytime or at nighttime on BP rhythm restoration and arterial stiffness in young and middle-aged non-dipper hypertensive patients. Participants will be randomly assigned to nifedipine GITS (gastrointestinal therapeutic system) 30 mg or amlodipine besylate 5 mg once daily, either taken in the morning or at night. Subjects will be divided into the following groups: group A. nifedipine administrated in the morning (N-M); B. nifedipine at night (N-N); C. amlodipine in the morning (A-M); D. amlodipine at night (A-N). If BP is not at goal during 4 week's visit, dosage of antihypertensive agents will be doubled. BP is measured via 24-hour ambulatory BP monitoring (ABPM) and arterial stiffness is examined before and after 8 weeks of pharmaceutical intervention. The primary endpoint is the difference of average nighttime systolic BP reduction between nifedipine GITS and amlodipine. The second endpoint is the percentage of restoration of a dipper rhythm at 8 weeks. The potential of nighttime dosing on arterial stiffness is also investigated. A sample size of 120 will have 80% power to detect a 3 mm Hg nighttime systolic BP difference between 2 drugs determined with ABPM.

CONCLUSIONS

NARRAS study is the first RCT to evaluate the effects of nifedipine GITS and amlodipine besylate on restoration of dipping rhythm and arterial elasticity, either administrated in the morning or evening, in younger non-dipper hypertensive subjects. The findings of NARRAS are likely to be potential to facilitate new therapeutic strategies for this condition.

TRIAL REGISTRATION NUMBER

NARRAS was registered in clinicaltrials.gov, NCT02940548.

Cardiovascular diseases: a therapeutic perspective around the clock

Biological rhythms are a ubiquitous feature of life. Most bodily functions, including physiological, biochemical, and behavioral processes, are coupled by the circadian rhythm. In the cardiovascular system, circadian fluctuations regulate several functions, namely heart rate, blood pressure, cardiac contractility, and metabolism. In fact, current lifestyles impose external timing constraints that clash with our internal circadian physiology, often increasing the risk of cardiovascular disease (CVD). Still, the mechanisms of dysregulation are not fully understood because this is a growing area of research. In this review, we explore the modulatory role of the circadian rhythms on cardiovascular function and disease as well as the role of chronotherapy in the context of CVD and how such an approach could improve existing therapies and assist in the development of new ones.

Relationship of vitamin D and parathyroid hormone with the nocturnal blood pressure decline in hypertension

OBJECTIVES

Vitamin D deficiency and high parathyroid hormone (PTH) levels have been linked with hypertension. Nondipper hypertension is associated with increased morbidity and mortality. We aimed to investigate the relationship of vitamin D and PTH levels with nondipper hypertension and nocturnal decline in untreated hypertensive patients.

PATIENTS AND METHODS

This cross-sectional study included a total of 73 hypertensive and 34 normotensive participants. Each patient underwent 24-hour ambulatory blood pressure monitoring, routine biochemical tests, vitamin D, and PTH analysis.

RESULTS

The study population was divided into three groups according to ambulatory blood pressure monitoring records: 40 nondippers (mean age; 59.8±10.8 years, 24 women and 16 men), 33 dipper hypertensives (mean age; 58±11.8 years, 13 women and 20 men), and 34 normotensives (mean age; 56.9±11.7 years, 19 women and 15 men). Nondipper hypertensives showed lower levels of vitamin D than dippers and normotensives (9.7±6.1 vs. 14.9±10.1 vs. 16.4±9.5 ng/ml, P=0.001, for both) and higher levels of PTH than dippers (74.8±34.7 vs. 53.3±19.9 ng/ml, P=0.001). A significant positive correlation was observed between vitamin D and nocturnal decline (r=0.34, P=0.001), whereas a significant negative correlation was present between PTH and nocturnal decline(r=-0.26, P=0.006). In multivariate analysis, PTH level was correlated independently with nocturnal decline (β=-0.07, 95% confidence interval: -0.114-0.025, P=0.003).

CONCLUSION

In this study, vitamin D levels were significantly lower and PTH levels were significantly higher in nondippers. The vitamin D level was correlated positively and the PTH level was correlated negatively with nocturnal decline. In addition, PTH level was associated independently with nocturnal decline in hypertension.

Circadian clock-mediated regulation of blood pressure

Most bodily functions vary over the course of a 24h day. Circadian rhythms in body temperature, sleep-wake cycles, metabolism, and blood pressure (BP) are just a few examples. These circadian rhythms are controlled by the central clock in the suprachiasmatic nucleus (SCN) of the hypothalamus and peripheral clocks located throughout the body. Light and food cues entrain these clocks to the time of day and this synchronicity contributes to the regulation of a variety of physiological processes with effects on overall health. The kidney, brain, nervous system, vasculature, and heart have been identified through the use of mouse models and clinical trials as peripheral clock regulators of BP. The dysregulation of this circadian pattern of BP, with or without hypertension, is associated with increased risk for cardiovascular disease. The mechanism of this dysregulation is unknown and is a growing area of research. In this review, we highlight research of human and mouse circadian models that has provided insight into the roles of these molecular clocks and their effects on physiological functions. Additional tissue-specific studies of the molecular clock mechanism are needed, as well as clinical studies including more diverse populations (different races, female patients, etc.), which will be critical to fully understand the mechanism of circadian regulation of BP. Understanding how these molecular clocks regulate the circadian rhythm of BP is critical in the treatment of circadian BP dysregulation and hypertension.

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.

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.

Non-dipping blood pressure patterns and arterial stiffness parameters in patients with Behcet's disease

Behcet's disease is a multisystemic vasculitis involving veins and arteries of various sizes. Non-dipping status, augmentation index and pulse wave velocity are important determinants of cardiovascular mortality and morbidity. We investigated the non-dipping status and arterial stiffness in patients with Behcet's disease. In this cross-sectional study, we examined the vascular parameters of 96 patients with Behcet's disease (53% female) and 60 age- and sex-matched control subjects. The non-dipping status and arterial distensibility were assessed using a Mobil-O-Graph Arteriograph, an automatic oscillometric device. In total, 65.6% of 96 patients were systolic non-dippers, and 34.4% exhibited high augmentation indices. Ten percent of the control subjects were systolic non-dippers, and 11.7% exhibited high augmentation indices. Nocturnal decreases in systolic blood pressure correlated with central systolic blood pressure and diastolic blood pressure, as well as nocturnal decreases in diastolic blood pressure. Furthermore, non-dipper patients with Behcet's disease exhibited higher nocturnal cardiac outputs than did dipper patients with Behcet's disease. Augmentation index correlated negatively with C-reactive protein and correlated positively with both 24 h and nocturnal peripheral resistance, as well as 24 h pulse wave velocity. The patients with high augmentation indices exhibited lower creatinine clearance, as well as lower nocturnal cardiac outputs, higher 24 h peripheral resistance and higher 24 h pulse wave velocities. Non-dipping status and arterial stiffness may exacerbate the harmful cardiovascular effects of the other. In addition to conventional risk factors, non-dipping status and arterial stiffness should be examined during the follow-up evaluations of patients with Behcet's disease.

Determination of correlation among heart rate variability, left atrium global strain, and nighttime blood pressure among patients with tinnitus

Background

We aimed to examine the correlation among nighttime blood pressure, heart rate variability, and left atrium peak systolic global longitudinal strain among patients with subjective tinnitus.

Material/Methods

Eighty patients with tinnitus were assigned to Group 1 and 80 healthy individuals were assigned to Group 2. Clinical blood pressure measurements, ambulatory blood pressure monitoring, and Holter electrocardiography monitoring were performed. All of the cases included in the study were examined with conventional echocardiography and 2-dimensional speckle tracking echocardiography.

Results

Mean nighttime systolic blood pressure (130.3±5.4) and mean nighttime diastolic blood pressure (82.8±3.9) in Group 1 were higher than in Group 2 (125.1±5.4 and 80.7±4.7, respectively) (p<0.05). Mean heart rate in Group 1 was significantly lower than in Group 2 but there was no statistically significant difference between the groups in terms of heart rate variability parameters and left atrium peak systolic global longitudinal strain values (p>0.05).

Conclusions

Nighttime systolic blood pressure and nighttime diastolic blood pressure were higher among the patients with tinnitus. In light of these results, we can conclude that both clinical blood pressure measurement and ambulatory blood pressure monitoring are important for patients with tinnitus.

Syndromes of orthostatic intolerance: a hidden danger

Orthostatic hypotension (OH) is a relatively common heterogenous and multifactorial disorder, traditionally classified as neurogenic (less common but often more severe) or nonneurogenic (more common, with no direct signs of autonomic nervous system disease). The different clinical variants of orthostatic intolerance include initial, classical and delayed OH as well as postural tachycardia syndrome. Orthostatic instability may induce syncopal attacks either alone or in combination with other mechanisms, and is often dismissed as a precipitating factor. Moreover, prevalent OH is an independent risk factor for all-cause mortality and cardiovascular morbidity, and the majority of patients with OH are asymptomatic or have few nonspecific symptoms. Management of symptomatic orthostatic intolerance includes both nonpharmacological and pharmacological methods, but it is not always successful and may lead to complications. Future studies of OH should focus on mechanisms that lead to neurogenic and nonneurogenic OH, novel diagnostic methods and more effective therapeutic modalities.

Chronobiological analysis of blood pressure in a patient with atrial fibrillation at the development of heart failure and its therapeutic and surgical treatment

Dynamics of blood pressure (BP) and heart rate (HR) was traced by automatic monitoring every 30 min uninterruptedly along several months in a patient suffering from combined atrial fibrillation and heart failure during the development of disease and its therapeutic and surgical treatment (pacemaker implanting and atrioventricular ablation). Analyses of spectral components as well as signal's shape revealed instabilities in circadian and semicircadian parameters. A new approach for signal's form description without using cosine approximation is suggested. The meaning that referring a patient as dipper, night peaker, or nondipper might be useful at choosing tactics of his treatment is impugned, because all these "types" can transform themselves in the same person in few days. Optimization timing of treatment provides better results if not the "types" of daily profile would be taken to account but the real form of the BP-signal and timing its first and second derivatives.

Evaluation of biochemical, hematological, and thyroid function parameters in nondipper and dipper hypertensive patients

AIM OF THE STUDY

In this study we investigated the effects of biochemical, hematologic, and thyroid function parameters on the circadian rhythm of hypertensive patients whose 24-h ambulatory blood pressure was being followed.

METHODS

We studied the fasting glucose, urea, creatinine, uric acid, aspartate transaminase, alanine aminotransferase, gamma-glutamyl transferase, total protein, albumin, lipid profiles, sodium, potassium, hemoglobin, white blood cell count, platelet count, mean platelet volume, thyroid stimulating hormone, free thyroid hormone values obtained simultaneously with 24-h ambulatory blood pressure results, as documented in the case records of 470 patients.

PATIENTS

Of the patients, 398 were in the nondipper hypertensive group and 72 in the dipper hypertensive group. Differences in serum biochemical, hematologic, and thyroid function parameters were compared between the groups.

RESULTS

No statistically meaningful difference was detected between the age, gender, biochemical and hematologic parameters of the two groups. When the two were compared with respect to thyroid function tests, thyroid stimulating hormone levels in the nondipper hypertensive group were significantly higher, while free triiodothyronine and thyroxine levels were significantly lower.

CONCLUSIONS

Thyroid function disorders are associated with hypertension. However, there are not enough data on the effects of thyroid hormones particularly on the nighttime blood pressure decrease in hypertensive patients. Although the exact mechanism between low thyroid hormone levels and nondipping hypertension development is not known, relatively low thyroid hormone levels in the nondipper group may be related to the decrease in vein wall compliance, considering the vascular effect of overt hypothyroidism.

Out-of-office blood pressure: from measurement to control

Hypertension is an important risk factor for the development of cardiovascular disease, and is a major cause of morbidity and mortality worldwide. Traditionally, hypertension diagnosis and treatment and clinical evaluations of antihypertensive efficacy have been based on office blood pressure (BP) measurements; however, there is increasing evidence that office measures may provide inadequate or misleading estimates of a patient’s true BP status and level of cardiovascular risk. The introduction, and endorsement by treatment guidelines, of 24-hour ambulatory BP monitoring and self (or home) BP monitoring has facilitated more reliable and reproducible estimations of true BP, including the identification of white-coat and masked hypertension, and evaluation of BP variability. In addition, ambulatory BP monitoring enables accurate assessment of treatment effectiveness over 24 hours and both ambulatory and self BP monitoring may lead to better tailoring of therapy according to BP profile and concomitant disease. This review describes the clinical benefits and limitations of out-of-office assessments and their applications for effective management of hypertension and attainment of BP control.

A survey of recent reports on ambulatory blood pressure monitoring

This article is a review of 25 publications on ambulatory blood pressure monitoring (ABPM) and the importance of its results in everyday clinical practice. These studies, published in 2008-2011, were selected from the Scopus database, but are also available in Pubmed. They were prepared by researchers from around the world, concerned with the problems of proper control of blood pressure (BP), and of abnormalities in the circadian pattern of BP in patients with arterial hypertension, diabetes mellitus or renal failure. In the first part of this article, I analyse publications focused on some nuances in the methodology of ABPM and recommend ways to avoid some traps, related not only to the individual patient but also to the device used and the technical staff. The next section is devoted to the advantages of ABPM as a diagnostic tool which enables clinicians to learn about patients’ BP during sleep, and emphasizes the practical implications of this information for so-called chronotherapy. This section also presents some new studies on the prognostic value of ABPM in patients with cardiovascular (CV) risk. Some recent articles on the results of various methods of pharmacological treatment of arterial hypertension in different age groups are then described. The observations presented in this article may be helpful not only for researchers interested in the chronobiology of the CV system, but also for general practitioners using ABPM.

The circadian clock in the kidney

Circadian variations in renal function were first described in the 19th century, and GFR, renal blood flow, urine production, and electrolyte excretion exhibit daily oscillations. These clinical observations are well established, but the underlying mechanisms that govern circadian fluctuations in kidney are not fully understood. Here we provide a brief overview of the machinery governing the circadian clock and examine the clinical and molecular evidence supporting a critical role for circadian rhythm in the kidney. There is a connection between BP oscillation and renal disease that supports the use of chronotherapy in the treatment of hypertension or correction of nondipping BP. Such studies support a developing model of clock controlled sodium and water transport in renal epithelial cells. Recent advances in identifying novel clock-controlled genes using rodent and cellular models also shed light on the molecular mechanisms by which the circadian clock controls renal function; however, the field is new and much more work remains.

Morbidity and mortality of orthostatic hypotension: implications for management of cardiovascular disease

Orthostatic hypotension (OH) is the failure of cardiovascular reflexes to maintain blood pressure on standing from a supine or sitting position. Although OH may cause symptoms of dizziness or syncope, asymptomatic OH (AOH) is far more common and is an independent risk factor for mortality and cardiovascular disease (CVD). The prevalence of AOH increases with age, the presence of hypertension or diabetes and the use of antihypertensive or other medications. The implications of AOH for the treatment of CVD and hypertension are not well defined. This review provides an overview of the current information on this topic and recommends the more frequent assessment of OH in clinical practice and in future clinical trials.