Night-time blood pressure patterns and target organ damage: a review

Discrimination and hypertension among a diverse sample of racial and sexual minority men living with HIV: baseline findings of a longitudinal cohort study

Racial and sexual orientation discrimination may exacerbate the double epidemic of hypertension (HTN) and HIV that affects men of color who have sex with men (MSM). This was a cross-sectional analysis of African American, Asian American, Native Hawaiian, or Pacific Islander (NHPI) MSM living with HIV (PLWH) cohort in Honolulu and Philadelphia. Racial and sexual orientation discrimination, stress, anxiety, and depression were measured with computer-assisted self-interview questionnaires (CASI). We examined the associations between racial and sexual orientation discrimination with hypertension measured both in the office and by 24-h ambulatory blood pressure monitoring (ABPM) using multivariable logistic regression. Sixty participants (60% African American, 18% Asian, and 22% NHPI) completed CASIs and 24-h ABPM. African American participants (80%) reported a higher rate of daily racial discrimination than Asian American (36%) and NHPI participants (17%, p < 0.001). Many participants (51%) reported daily sexual orientation discrimination. Sixty-six percent of participants had HTN by office measurement and 59% had HTN by 24-h ABPM measurement. Participants who experienced racial discrimination had greater odds of having office-measured HTN than those who did not, even after adjustment (Odds Ratio 5.0 (95% Confidence Interval [1.2-20.8], p = 0.03)). This association was not seen with 24-h ABPM. Hypertension was not associated with sexual orientation discrimination. In this cohort, MSM of color PLWH experience significant amounts of discrimination and HTN. Those who experienced racial discrimination had higher in-office blood pressure. This difference was not observed in 24-h APBM and future research is necessary to examine the long-term cardiovascular effects.

Exenatide administration time determines the effects on blood pressure dipping in db/db mice via modulation of food intake and sympathetic activity

Type 2 diabetics have an increased prevalence of hypertension and nondipping blood pressure (BP), which worsen cardiovascular outcomes. Exenatide, a short acting glucagon-like peptide-1 receptor agonist (GLP-1RA) used to treat type 2 diabetes, also demonstrates blood pressure (BP)-lowering effects. However, the mechanisms behind this and the impact of administration timing on BP dipping remain unclear. We investigated the effects of exenatide intraperitoneal injected at light onset (ZT0) or dark onset (ZT12) in diabetic (db/db) mice and nondiabetic controls. Using radio-telemetry and BioDAQ cages, we continuously monitored BP and food intake. Db/db mice exhibited non-dipping BP and increased food intake. ZT0 exenatide administration restored BP dipping by specifically lowering light-phase BP, while ZT12 exenatide reversed dipping by lowering dark-phase BP. These effects correlated with altered food intake patterns, and importantly, were abolished when food access was removed. Additionally, urinary norepinephrine excretion, measured by HPLC, was significantly reduced 6 hours post-exenatide at both ZT0 and ZT12, suggesting sympathetic nervous system involvement. Notably, combining exenatide with either ganglionic blocker mecamylamine or α-blocker prazosin did not enhance BP reduction beyond the individual effects of each blocker. These findings reveal that exenatide, when administered at light onset, restores BP dipping in db/db mice by suppressing light-phase food intake and sympathetic activity. Importantly, the efficacy of exenatide is dependent on food availability and its timing relative to circadian rhythms, highlighting the potential for chronotherapy in optimizing GLP-1RA- based treatments for type 2 diabetes and hypertension.

Graphic Abstract

Article Highlights

Maintaining a normal blood pressure (BP) circadian rhythm is vital for cardiovascular health, but diabetes often disrupts this rhythm. The effect of exenatide, a GLP-1 receptor agonist (GLP-1RA), on BP rhythm in diabetes is uncertain.This study investigates the impact of exenatide administration timing on BP patterns in diabetic db/db mice.Findings indicate that exenatide given at the onset of rest restores normal BP dipping, while at the start of the active phase worsens BP rhythm by modulating food intake and sympathetic activity.Timing GLP-1 RA administration may optimize BP control and provide cardiovascular benefits for type 2 diabetes patients.

High-Frequency Heart Rate Variability Is Prospectively Associated With Sleep Complaints in a Healthy Working Cohort

OBJECTIVE

Vagus nerve functioning, as indexed by high-frequency heart rate variability (HF-HRV), has been implicated in a wide range of mental and physical health conditions, including sleep complaints. This study aimed to test associations between HF-HRV measured during sleep (sleep HF-HRV) and subjective sleep complaints 4 years later.

METHODS

One hundred forty-three healthy employees (91% male; MAge = 47.8 years [time 2], SD = 8.3 years) of an industrial company in Southern Germany completed the Jenkins Sleep Problems Scale, participated in a voluntary health assessment, and were given a 24-hour ambulatory heart rate recording device in 2007. Employees returned for a health assessment and completed the Jenkins Sleep Problems Scale 4 years later.

RESULTS

Hierarchical regression analyses showed that lower sleep HF-HRV measured in 2007 was associated with higher self-reported sleep complaints 4 years later after controlling for covariates (rab,c = -0.096, b = -0.108, 95% CI, -0.298 to 0.081, ΔR2 = 0.009, p = .050).

CONCLUSIONS

These data are the first to show that lower sleep HF-HRV predicted worse sleep 4 years later, highlighting the importance of vagus nerve functioning in adaptability and health.

Postoperative Dipping Patterns of Mean Arterial Pressure and Mortality After Coronary Artery Bypass Grafting

Blood pressure dipping patterns have long been considered to be associated with adverse events. We aimed to investigate whether dipping patterns of postoperative MAP were related to 90-day and hospital mortality in patients undergoing CABG. Four thousand three hundred ninety-one patients were classified into extreme dippers (night-to-day ratio of MAP ≤ 0.8), dippers (0.8 < night-to-day ratio of MAP ≤ 0.9), non-dippers (0.9 < night-to-day ratio of MAP ≤ 1), and reverse dippers (> 1). Compared with non-dippers, reverse dippers were at a higher risk of 90-day mortality (aHR = 1.58; 95% CI, 1.10-2.27) and hospital mortality (aOR = 1.97; 95% CI, 1.12-3.47). A significant interaction was observed between hypertension and dipping patterns (P for interaction = 0.02), with a significant increased risk of 90-day mortality in non-hypertensive reverse dippers (aHR = 1.90; 95% CI, 1.17-3.07) but not in hypertensive reverse dippers (aHR = 1.26; 95% CI, 0.73-2.19).

Impact of sleep-disordered breathing on overnight changes in arterial stiffness in patients with acute heart failure

Overnight increases in arterial stiffness associated with sleep-disordered breathing may adversely affect patients with acute heart failure. Thus, we investigated overnight changes in arterial stiffness and their association with sleep-disordered breathing in patients hospitalized for acute heart failure. Consecutive patients with acute heart failure were enrolled. All participants underwent overnight full polysomnography following the initial improvement of acute signs and symptoms of acute heart failure. The arterial stiffness parameter, cardio-ankle vascular index (CAVI), was assessed before and after polysomnography. Overall, 60 patients (86.7% men) were analyzed. CAVI significantly increased overnight (from 8.4 ± 1.6 at night to 9.1 ± 1.7 in the morning, P < 0.001) in addition to systolic and diastolic blood pressure (from 114.1 mmHg to 121.6 mmHg, P < 0.001; and from 70.1 mmHg to 78.2 mmHg, P < 0.001, respectively). Overnight increase in CAVI (ΔCAVI ≥ 0) was observed in 42 patients (70%). The ΔCAVI ≥ 0 group was likely to have moderate-to-severe sleep-disordered breathing (i.e., apnea-hypopnea index ≥15, 55.6% vs 80.9%, P = 0.047) and greater obstructive respiratory events (29.4% vs 58.5%, P = 0.041). In multivariable analysis, moderate-to-severe sleep-disordered breathing and greater obstructive respiratory events were independently correlated with an overnight increase in CAVI (P = 0.033 and P = 0.042, respectively). In patients hospitalized for acute heart failure, arterial stiffness, as assessed by CAVI, significantly increased overnight. Moderate-to-severe sleep-disordered breathing and obstructive respiratory events may play an important role in the overnight increase in cardio-ankle vascular index.

Cross-sectional associations between short and mid-term blood pressure variability, cognition, and vascular stiffness in older adults

Background

High blood pressure variability (BPV), particularly in older age, appears to be an independent risk factor for incident dementia. The current study aimed to investigate the association between different BPV measures (short- and mid-term BPV including circadian patterns) and cognitive functioning as well as vascular stiffness measures to better understand the role that BPV plays in cognitive impairment.

Methods

70 older adults (60-80-year-olds) without dementia completed a cognitive test battery and had their blood pressure (BP) assessed via a 24-hour ambulatory BP monitor (divided into sleep and wake for short-term BPV) and 4-day morning and evening home-based BP monitor (for day-to-day BPV). Arterial stiffness was evaluated via pulse wave analysis and pulse wave velocity (PWV) and cerebrovascular pulsatility was assessed via transcranial doppler sonography of the middle cerebral arteries.

Results

High systolic as well as diastolic short- and mid-term BPV were associated with poorer cognitive functioning, independent of the mean BP. Higher short-term BPV was associated with poorer attention and psychomotor speed, whilst day-to-day BPV was negatively linked with executive functioning. Circadian BP patterns (dipping and morning BP surge) showed no significant relationships with cognition after adjusting for covariates. Higher systolic short-term BPV was associated with higher arterial stiffness (PWV) and higher diastolic day-to-day BPV was linked with lower arterial stiffness. No significant associations between BPV measures and cerebrovascular pulsatility were present.

Conclusion

High BPV, independently of the mean BP, is associated with lower cognitive performance and increased arterial stiffness in older adults without clinically-relevant cognitive impairment. This highlights the role of systolic and diastolic BPV as a potential early clinical marker for cognitive impairment.

Effects of Nondipping Blood Pressure Changes: A Nephrologist Prospect

Blood pressure (BP) variations depend on various internal, environmental, and behavioral factors. BP fluctuations occur both in normotensive and hypertensive people. Although it fluctuates over the 24-hr day and night, the morning BP increases after waking up and declines throughout sleep. It is typical for BP to decrease by 10% to 20%, while sleeping, known as dipping BP. However, if there is no decrease in nighttime mean systolic BP or a drop of less than 10 mmHg, it is called nondipping BP. Conversely, reverse dipping BP means an increase in mean systolic BP instead of a drop during the night. Reverse dipping is observed in hypertension (HTN), diabetes mellitus (DM), chronic kidney disease (CKD), and obstructive sleep apnea (OSA) syndrome. The introduction of ambulatory BP monitoring (ABPM) led to the emergence of identifying normal and elevated BP patterns. Non-dipping BP increases the risk of cardiovascular system (CVS) complications such as left ventricular hypertrophy, proteinuria, glomerular filtration rate (GFR) reduction, and CKD progression. A loss or blunting of the normal BP profile is recognized as a deleterious variant, and restoring abnormal BP patterns has been reported to significantly impact end-organ damage, morbidity, and mortality. In this non-systematic clinically-oriented, comprehensive review, we aim to update the BP variables and the pathophysiology of nondipping BP and point out the areas which need more investigation from a nephrology perspective because the nondipping BP increases the risk of proteinuria, GFR reduction, and CKD progression. A literature search of PubMed, Google, EMBASE, and Google Scholar was conducted. Checks of selected papers and relevant reviews complemented the electronic search. With improved BP measurement methods, the physiology of BP profile variations is readily detectable during the day and night. A nondipping BP profile is a distinct BP pattern that may have significant end-organ damage effects and therapeutic importance for nephrologists. The pathophysiology of the nondipping BP variant must be clarified to prevent complications, and further investigations are required. Furthermore, there is debate about the best BP index to utilize: systolic BP, diastolic BP, mean arterial pressure, or a mixture of all. All these areas are important and need new research projects.

Relationships between Easily Available Biomarkers and Non-Dipper Blood Pressure Pattern in Patients with Stable Coronary Artery Disease

Introduction. Chronic inflammation plays an essential role in the pathophysiology of both arterial hypertension (HTN) and coronary artery disease (CAD), and is more pronounced in individuals with a non-dipper circadian blood pressure (BP) pattern. A non-dipping BP pattern is in turn is associated with increased cardiovascular morbi-mortality, and a higher risk of atherosclerotic events. Neutrophil to lymphocyte ratio (NLR), monocyte to lymphocyte ratio (MLR) and platelet to lymphocyte ratio (PLR) are readily available predictors of systemic inflammation and cardiovascular risk. The purpose of our study is to evaluate whether NLR, MLR and PLR can be used as cost-effective predictors of a non-dipping blood pressure pattern in hypertensive patients with stable CAD. Materials and Methods: We performed a cross-sectional retrospective analysis that included 80 patients with hypertension and stable CAD (mean age 55.51 ± 11.83 years, 71.3% male) referred to a cardiovascular rehabilitation center. All patients underwent clinical examination, 24 h ambulatory blood pressure monitoring (ABPM) and standard blood analysis. Results: Baseline demographic characteristics were similar in both groups. Patients with non-dipper pattern had significantly higher NLR (median = 2, IR (2–3), p < 0.001), MLR (median = 0.31, IR (0.23–0.39), p < 0.001) and PLR (median = 175, IR (144–215), p < 0.001) compared to dippers. Conclusion: Our results suggest that MLR and PLR are inexpensive and easily accessible biomarkers that predict a non-dipping pattern in hypertensive patients with stable CAD.

Role of sympathetic pathway in light-phase time-restricted feeding-induced blood pressure circadian rhythm alteration

Disruption of blood pressure (BP) circadian rhythm, independent of hypertension, is emerging as an index for future target organ damage and is associated with a higher risk of cardiovascular events. Previous studies showed that changing food availability time alters BP rhythm in several mammalian species. However, the underlying mechanisms remain largely unknown. To address this, the current study specifically investigates (1) the relationship between rhythms of food intake and BP in wild-type mice; (2) effects of light-phase time-restricted feeding (TRF, food only available during light-phase) on BP circadian rhythm in wild-type and diabetic db/db mice; (3) the roles of the autonomic system and clock gene in light-phase TRF induced changes in BP circadian rhythm. Food intake and BP of C57BL/6J and db/db mice were simultaneously and continuously recorded using BioDAQ and telemetry systems under ad libitum or light-phase TRF. Per2 protein daily oscillation was recorded in vivo by IVIS spectrum in mPer2 Luc mice. Autonomic nerve activity was evaluated by heart rate variability, baroreflex, urinary norepinephrine (NE) and epinephrine (Epi) excretion, and mRNA expressions of catecholamines biosynthetic and catabolic enzymes, and alpha-adrenergic receptors in mesenteric resistance arteries. We found that in wild-type mice, the BP level was correlated with the food intake temporally across the 24 h. Reversing the feeding time by imposing light-phase TRF resulted in reverse or inverted BP dipping. Interestingly, the net changes in food intake were correlated with the net alteration in BP temporally under light-phase TRF. In db/db mice, light-phase TRF worsened the existing non-dipping BP. The food intake and BP circadian rhythm changes were associated with alterations in Per2 protein daily oscillation and the time-of-day variations in heart rate variability, baroreflex, and urinary excretion of NE and Epi, and increased mRNA expression of Slc6a2 (encoding NE transporter) and Adra1d (encoding alpha-adrenergic receptor 1d) in the mesenteric resistance arteries, indicating the sympathetic nervous system (SNS) was modulated after light-phase TRF. Collectively, our results demonstrated that light-phase TRF results in reverse dipping of BP in wild-type and diabetic db/db mice and revealed the potential role of the sympathetic pathway in light-phase TRF-induced BP circadian rhythm alteration.

Harm of circadian misalignment to the hearts of the adolescent wistar rats

PURPOSE

The purpose of this study was to observe the harm of circadian misalignment (CM), caused by an inverted photoperiod (IP), on the hearts of the adolescent Wistar rats, and to explore the mechanisms leading to harm.

METHODS

An IP was used to create a CM model. A total of 174 Wistar rats were randomly divided into circadian alignment (CA) and CM groups (87 rats per group). The different activity rhythms of the two groups of rats were adjusted through different light/dark cycles for 90 days. We recorded the rhythmic activity trajectory and sleep time of the rats. After 90 days of modeling, we performed various analyses (i.e., blood pressure, weight, cardiac ultrasound tests, serological tests, cardiac tissue immunofluorescence, immunohistochemistry, transmission electron microscopy on myocardial mitochondria, western blotting, and quantitative polymerase chain reactions).

RESULTS

(1) The IP protocol caused CM in rats. (2) CM rats showed significantly higher blood pressure during the day (resting phase). They also showed significantly higher serum levels of angiotensin II and epinephrine during the day compared to the CA rats. (3) CM caused up-regulation of gene expression of adrenergic receptors α1 (α1-AR) and β1 (β1-AR) and down-regulation of the glucocorticoid receptor (Gr) gene expression in rat hearts. It also caused downregulation of Bmal1 expression. In addition, the changes in Bmal1 and Per2 correlated with the changes in β1-AR and α1-AR. (4) CM had adverse effects on multiple molecular proteins of the heart. (5) CM increased the collagen fibers in the rat heart and increased the destruction of mitochondria. (6) Eventually, CM caused a decrease in the pumping function of the heart and decreased the coronary blood flow rate.

CONCLUSIONS

(1) CM significantly affected the cardiac structure and function in the adolescent rats through a variety of mechanisms. (2) CM can regulate the expression of myocardial clock genes, and it is likely to have an impact on the heart through this pathway.

Efficacy of angiotensin receptor neprilysin inhibitor in Asian patients with refractory hypertension

Sacubitril/valsartan, simultaneously inhibits neprilysin and angiotensin II receptor, showed an effect in reducing blood pressure (BP). The authors aimed to study whether it can be used as an antihypertensive agent in patients with refractory hypertension who have already been treated. A total of 66 Chinese patients with refractory hypertension were enrolled. Patients received sacubitril/valsartan  200 instead of angiotensin II receptor blocker or angiotensin converting enzyme inhibitor while other agents continued. If BP was uncontrolled after 4 weeks, sacubitril/valsartan was increased to 400 mg. The BP reduction was evaluated by office BP and ambulatory BP monitoring after 8‐week treatment. The baseline office BP and mean arterial pressure (MAP) were 150.0/95.0 mmHg and 113.3 mmHg. BP and MAP reduced to 130.6/83.2 mmHg and 99.0 mmHg at week 8. Office BP and MAP reductions were 19.4/11.8 mmHg and 14.3 mmHg at endpoint (all p < .001). The 24‐h, daytime and nighttime ambulatory BP were 146.2/89.1, 148.1/90.3, and 137.5/83.7 mmHg, respectively at baseline, and BP reduced to 129.6/79.8, 130.6/81.1, and 121.7/75.8 mmHg, respectively at week 8. The 24‐h, daytime and nighttime ambulatory BP reductions were 16.6/9.3, 17.5/9.2, and 15.8/7.9 mmHg, respectively at endpoint (all p < .001). Sacubitril/valsartan significantly reduced office and ambulatory BP in refractory hypertension patients. Our study provided new evidence for sacubitril/valsartan in refractory hypertension.

Methods of Blood Pressure Measurement to Predict Hypertension-Related Cardiovascular Morbidity and Mortality

PURPOSE OF REVIEW

As the evidence on different blood pressure phenotypes and their cardiovascular risks evolve, it is imperative to evaluate the reliability of office blood pressure (OBP), ambulatory blood pressure (ABP), and home blood pressure (HBP) measurements and their associations with cardiovascular morbidity and mortality.

RECENT FINDINGS

HBP is more reliable in diagnosis of hypertension than OBP or ABP. HBP correlates better with left ventricular mass index (LVMI). Increasing systolic HBP is associated with a higher risk of all-cause mortality, cardiovascular mortality, and cardiovascular events. An elevated systolic ABP is also associated with a higher risk of cardiovascular events and mortality. ABP is a better predictor of cardiovascular events than OBP in diabetics. ABP and HBP furnish additional information beyond OBP. They correlate better with cardiovascular outcomes and are more helpful with monitoring therapy than OBP. Comparative effectiveness studies of all three methods associating with cardiovascular outcomes are warranted.

Subclinical cardiac dysfunction in pediatric kidney transplant recipients identified by speckle-tracking echocardiography

BACKGROUND

Kidney transplantation (KTx) improves prognosis in children with kidney failure; still, these patients are prone to cardiovascular damage due to multiple risk factors. Our aim was to assess myocardial structure and function in pediatric KTx by conventional and speckle-tracking echocardiography (STE) in association with established cardiovascular risk factors.

METHODS

Forty-two KTx and 39 healthy age- and gender-matched children were evaluated. KTx recipients were further categorized according to the control of hypertension assessed by 24-h ambulatory blood pressure monitoring (ABPM). Subjects underwent pulse wave velocity (PWV) measurement, conventional echocardiography, and 2-dimensional STE. Left and right ventricular (LV, RV) global longitudinal strain (GLS), and LV circumferential strain (GCS) were measured. Glomerular filtration rate (eGFR) was calculated according to the Schwartz formula.

RESULTS

KTx patients had increased blood pressure and arterial stiffness. LV ejection fraction (EF) was preserved along with elevated LV mass index (LVMi) while LVGLS was significantly lower, whereas LVGCS and RVGLS were increased in KTx. Uncontrolled hypertensives had lower LVGLS compared to those with controlled hypertension. Using multiple forward stepwise regression analysis, 24-h SBP and relative wall thickness (RWT) were independent determinants of LVMi, whereas antihypertensive therapy, eGFR, and HOMA-IR were independent determinants of LVGLS.

CONCLUSIONS

Cardiac morphology and function show distinct changes after KTx. Along with comparable ventricular volumes, LV hypertrophy and subclinical myocardial dysfunction are present. Control of hypertension and kidney graft function are major factors of LV performance. STE may be useful to reveal early myocardial dysfunction in pediatric KTx. A higher resolution version of the Graphical abstract is available as Supplementary information.

Follow-Up of Blood Pressure, Arterial Stiffness, and GFR in Pediatric Kidney Transplant Recipients

Pediatric renal transplant recipients (RTx) were studied for longitudinal changes in blood pressure (BP), arterial stiffness by pulse wave velocity (PWV), and graft function.

Patients and Methods: 52 RTx patients (22 males) were included; office BP (OBP) and 24 h BP monitoring (ABPM) as well as PWV were assessed together with glycemic and lipid parameters and glomerular filtration rate (GFR) at 2.4[1.0–4.7] (T₁) and 9.3[6.3–11.8] years (T₂) after transplantation (median [range]).

Results: Hypertension was present in 67 and 75% of patients at T₁ and T₂, respectively. Controlled hypertension was documented in 37 and 44% by OBP and 40 and 43% by ABPM. Nocturnal hypertension was present in 35 and 30% at T₁ and T₂; 24 and 32% of the patients had masked hypertension, while white coat hypertension was present in 16 and 21% at T₁ and T₂, respectively. Blood pressure by ABPM correlated significantly with GFR and PWV at T₂, while PWV also correlated significantly with T₂ cholesterol levels. Patients with uncontrolled hypertension by ABPM had a significant decrease in GFR, although not significant with OBP. Anemia and increased HOMAi were present in ~20% of patients at T₁ and T₂.

Conclusion: Pediatric RTx patients harbor risk factors that may affect their cardiovascular health. While we were unable to predict the evolution of renal function based on PWV and ABPM at T₁, these risk factors correlated closely with GFR at follow-up suggesting that control of hypertension may have an impact on the evolution of GFR.

Heart rate turbulence measurements in patients with dipper and non-dipper hypertension: the effects of autonomic functions

Background/aim

Hypertensive patients have shown autonomic dysfunction that is closely associated with the measurements of heart rate variability (HRV) and heart rate turbulence (HRT). We aimed to show the alterations of HRV and HRT measurements in patients with both dipper and non-dipper hypertension.

Materials and methods

This was a retrospective study consisting of one hundred and twenty-three participants (mean age ± SD, 55.7 ± 14.8 years; range, 18–90 years). The participants were divided into two groups: Group1: The patients with dipper hypertension, Group2: The patients with non-dipper hypertension. Two cardiologists performed HRV and HRT using 24-h electrocardiography (ECG) Holter and ambulatory blood pressure monitoring (ABPM) of patients.

Results

The results indicated that patients in group 2 had higher low frequency power/high frequency power ratio (LF/HF), lower high frequency power (HF) , root mean square of standard deviation (RMSSD) values than group 1 (p = 0.007, p = 0.008, and p = 0.002, respectively). Group 2 also showed higher heart rate turbulence onset (HRTTO) and lower heart rate turbulence slope (HRTTS) values than Group 1 (p = 0.004, p = 0.001, respectively). We performed multivariate analysis and observed that HRTTS and HRTTO have statistically significant associations with the presence of dipper or non-dipper hypertension [F = 7.755, p = 0.001], LF/HF [F = 7.868, p = 0.001], and HF [F = 4.081, p = 0.020].

Conclusion

This study shows a statistically significant difference in HRT measurements between dipper and non-dipper hypertensive patients. Deteriorated autonomic circadian rhythm and autonomic functions may contribute to these results.

Early changes of immunoreactivity to orexin in hypothalamus and to RFamide peptides in brainstem during the development of hypertension

Baroreflex sensitivity (BRS) is an important function of the nervous system and essential for maintaining blood pressure levels in the physiological range. In hypertension, BRS is decreased both in man and animals. Although increased sympathetic activity is thought to be the main cause of decreased BRS, hence the development of hypertension, the BRS is regulated by both sympathetic (SNS) and parasympathetic (PNS) nervous system. Here, we analyzed neuropeptide changes in the lateral hypothalamus (LH), which favours the SNS activity, as well as in PNS nuclei in the brainstem of spontaneously hypertensive rats (SHR) and their normotensive controls (Wistar Kyoto rats- WKY). The analyses revealed that in the WKY rats the hypothalamic orexin system, known for its role in sympathetic activation, showed a substantial decrease when animals age. At the same time, however, such a decrease was not observed when hypertension developed in the SHR. In contrast, Neuropeptide FF (NPFF) and Prolactin Releasing Peptide (PrRP) expression in the PNS associated Nucleus Tractus Solitarius (NTS) and Dorsal Motor Nucleus of the Vagus (DMV) diminished substantially, not only after the establishment of hypertension but also before its onset. Therefore, the current results indicate early changes in areas of the central nervous system involved in SNS and PNS control of blood pressure and associated with the development of hypertension.

Capillary vascular density in the retina of hypertensive patients is associated with a non-dipping pattern independent of mean ambulatory blood pressure

BACKGROUND

A nocturnal non-dipping pattern has been associated with hypertension-mediated organ damage (HMOD), morbidity and mortality. Retinal imaging through application of modern technologies including optical coherence tomography angiography (OCT-A) can provide detailed insights into early vascular damage. In this observational study, we investigated the relationship of microscopic vascular density in the retina measured with OCT-A and nocturnal blood pressure (BP) dipping.

METHODS

Retinal OCT-A and ambulatory BP monitoring (ABPM) data prospectively obtained from 142 patients referred to a tertiary hypertension clinic were analysed with regression models for associations between BP night-time dipping and retinal capillary vascular density in three different zones around the fovea.

RESULTS

More pronounced nocturnal SBP and DBP dipping was significantly associated with increased vascular density in the central foveal area of the retina. These associations were robust to adjustment for other available risk factors including mean daytime BP. Parafoveal and whole image vascular density did not show equivalent significant associations with nocturnal BP dipping. The results were reproducible when assessed in a subgroup of patients who had concomitant type 2 diabetes.

CONCLUSION

Foveal vascular density was associated with the nocturnal BP dipping pattern in hypertensive patients. These associations were robust to adjustment of relevant factors such as daytime BP. Our findings highlight the importance of nocturnal BP features reflected in ambulatory BP monitoring in the assessment of HMOD. Whether routine assessment of retinal damage markers may improve risk management of hypertensive patients remains to be determined.

Management Strategies for Comorbid Supine Hypertension in Patients with Neurogenic Orthostatic Hypotension

PURPOSE OF REVIEW

In autonomic failure, neurogenic orthostatic hypotension (nOH) and neurogenic supine hypertension (nSH) are interrelated conditions characterized by postural blood pressure (BP) dysregulation. nOH results in a sustained BP drop upon standing, which can lead to symptoms that include lightheadedness, orthostatic dizziness, presyncope, and syncope. nSH is characterized by elevated BP when supine and, although often asymptomatic, may increase long-term cardiovascular and cerebrovascular risk. This article reviews the pathophysiology and clinical characteristics of nOH and nSH, and describes the management of patients with both nOH and nSH.

RECENT FINDINGS

Pressor medications required to treat the symptoms of nOH also increase the risk of nSH. Because nOH and nSH are hemodynamically opposed, therapies to treat one condition may exacerbate the other. The management of patients with nOH who also have nSH can be challenging and requires an individualized approach to balance the short- and long-term risks associated with these conditions. Approaches to manage neurogenic BP dysregulation include nonpharmacologic approaches and pharmacologic treatments. A stepwise treatment approach is presented to help guide neurologists in managing patients with both nOH and nSH.

Ambulatory blood pressure profile and stroke recurrence

OBJECTIVES

To establish a new ambulatory blood pressure (ABP) parameter (24-hour ABP profile) and evaluated its performance on stroke outcome in ischaemic stroke (IS) or transient ischaemic attack (TIA) patients.

METHODS

The prospective cohort consisted of 1996 IS/TIA patients enrolled for ABP monitoring and a 3-month follow-up for stroke recurrence as outcome. Profile groups of systolic blood pressure (SBP) were identified via an advanced functional clustering method, and the associations of the profile groups and conventional ABP parameters with stroke recurrence were examined in a Cox proportional hazards model.

RESULTS

Three discrete profile groups (n=604, 781 and 611 in profiles 1, 2 and 3, respectively) in 24-hour ambulatory SBP were identified. Profile 1 resembled most to the normal diurnal blood pressure pattern; profile 2 also dropped at night, but climbed earlier and with higher morning surge; while profile 3 had sustained higher nocturnal SBP without significant nocturnal SBP decline. The incidence of stroke recurrence was 2.9%, 3.9% and 5.5% in profiles 1, 2 and 3, respectively. After adjustment for covariates, profile 3 was significantly associated with higher risk of stroke recurrence with profile 1 as reference (HR 1.76, 95% CI: 1.00 to 3.09), while no significant difference was observed between profiles 2 and 1 (HR 1.22, 95% CI: 0.66 to 2.25). None of conventional ABP parameters showed significant associations with the outcome.

CONCLUSIONS

Ambulatory 24-hour SBP profile is associated with short-term stroke recurrence. Profiles of ABP may help improve identification of stroke recurrence by capturing the additive effects of individual ABP parameters.

Blood pressure dipping and sleep quality in the Wisconsin Sleep Cohort

AIMS

Nondipping blood pressure (BP) is associated with higher risk for hypertension and advanced target organ damage. Insomnia is the most common sleep complaint in the general population. We sought to investigate the association between sleep quality and insomnia and BP nondipping cross-sectionally and longitudinally in a large, community-based sample.

METHODS

A subset of the Wisconsin Sleep Cohort (n = 502 for cross-sectional analysis and n = 260 for longitudinal analysis) were enrolled in the analysis. Polysomnography measures were used to evaluate sleep quality. Insomnia symptoms were obtained by questionnaire. BP was measured by 24-h ambulatory BP monitoring. Logistic regression models estimated cross-sectional associations of sleep quality and insomnia with BP nondipping. Poisson regression models estimated longitudinal associations between sleep quality and incident nondipping over a mean 7.4 years of follow-up. Systolic and diastolic nondipping were examined separately.

RESULTS

In cross-sectional analyses, difficulty falling asleep, longer waking after sleep onset, shorter and longer total sleep time, lower sleep efficiency and lower rapid eye movement stage sleep were associated with higher risk of SBP and DBP nondipping. In longitudinal analyses, the adjusted relative risks (95% confidence interval) of incident systolic nondipping were 2.1 (1.3-3.5) for 1-h longer waking after sleep onset, 2.1 (1.1-5.1) for 7-8 h total sleep time, and 3.7 (1.3-10.7) for at least 8-h total sleep time (compared with total sleep time 6-7 h), and 1.9 (1.1-3.4) for sleep efficiency less than 0.8, respectively.

CONCLUSION

Clinical features of insomnia and poor sleep quality are associated with nondipping BP. Our findings suggested nondipping might be one possible mechanism by which poor sleep quality was associated with worse cardiovascular outcomes.

Nondipping Blood Pressure: Predictive or Reactive Failure of Renal Sodium Handling?

Blood pressure follows a daily rhythm, dipping during nocturnal sleep in humans. Attenuation of this dip (nondipping) is associated with increased risk of cardiovascular disease. Renal control of sodium homeostasis is essential for long-term blood pressure control. Sodium reabsorption and excretion have rhythms that rely on predictive/circadian as well as reactive adaptations. We explore how these rhythms might contribute to blood pressure rhythm in health and disease.

Multicomponent Analysis of Sleep Using Electrocortical, Respiratory, Autonomic and Hemodynamic Signals Reveals Distinct Features of Stable and Unstable NREM and REM Sleep

A new concept of non-rapid eye movement (NREM) and rapid eye movement (REM) sleep is proposed, that of multi-component integrative states that define stable and unstable sleep, respectively, NREM_S, NREM_US REM_S, and REM_US. Three complementary data sets are used: obstructive sleep apnea (20), healthy subjects (11), and high loop gain sleep apnea (50). We use polysomnography (PSG) with beat-to-beat blood pressure monitoring, and electrocardiogram (ECG)-derived cardiopulmonary coupling (CPC) analysis to demonstrate a bimodal, rather than graded, characteristic of NREM sleep. Stable NREM (NREM_S) is characterized by high probability of occurrence of the <1 Hz slow oscillation, high delta power, stable breathing, blood pressure dipping, strong sinus arrhythmia and vagal dominance, and high frequency CPC. Conversely, unstable NREM (NREM_US) has the opposite features: a fragmented and discontinuous <1 Hz slow oscillation, non-dipping of blood pressure, unstable respiration, cyclic variation in heart rate, and low frequency CPC. The dimension of NREM stability raises the possibility of a comprehensive integrated multicomponent network model of NREM sleep which captures sleep onset (e.g., ventrolateral preoptic area-based sleep switch) processes, synaptic homeostatic delta power kinetics, and the interaction of global and local sleep processes as reflected in the spatiotemporal evolution of cortical “UP” and “DOWN” states, while incorporating the complex dynamics of autonomic-respiratory-hemodynamic systems during sleep. Bimodality of REM sleep is harder to discern in health. However, individuals with combined obstructive and central sleep apnea allows ready recognition of REM_S and REM_US (stable and unstable REM sleep, respectively), especially when there is a discordance of respiratory patterns in relation to conventional stage of sleep.

Blood pressure monitoring in sleep: time to wake up

Hypertension is a highly common condition with well-established adverse consequences. Ambulatory blood pressure monitoring has repeatedly been shown to better predict cardiovascular outcomes and mortality, compared to single office visit blood pressure. Non-dipping of sleep-time blood pressure is an independent marker for increased cardiovascular risk. We review blood pressure variability and the challenges of blood pressure monitoring during sleep. Although pathological sleep such as obstructive sleep apnea has been associated with non-dipping of sleep-time blood pressure, blood pressure is not routinely measured during sleep due to lack of unobtrusive blood pressure monitoring technology. Second, we review existing noninvasive continuous blood pressure monitoring technologies. Lastly, we propose including sleep-time blood pressure monitoring during sleep studies and including sleep studies in patients undergoing ambulatory blood pressure monitoring.

Retinal microvasculature and masked hypertension in young adults: the African-PREDICT study

Masked hypertension is known to induce microvascular complications. However, it is unclear whether early microvascular changes are already occurring in young, otherwise healthy adults. We therefore investigated whether retinal microvascular calibers and acute responses to a flicker stimulus are related to masked hypertension. We used the baseline data of 889 participants aged 20-30 years who were taking part in the African Prospective study on the Early Detection and Identification of Cardiovascular Disease and Hypertension. Clinic and 24-h ambulatory blood pressure were measured. The central retinal artery equivalent (CRAE) and central retinal vein equivalent were calculated from fundus images, and retinal vessel dilation was determined in response to flicker light-induced provocation. A smaller CRAE was observed in those with masked hypertension vs. those with normotension (157.1 vs. 161.2 measuring units, P < 0.001). In forward multivariable-adjusted regression analysis, only CRAE was negatively related to masked hypertension [adjusted R² = 0.267, β = -0.097 (95% CI = -0.165; -0.029), P = 0.005], but other retinal microvascular parameters were not associated with masked hypertension. In multivariable logistic regression analyses, masked hypertension [OR = 2.333, (95% CI = 1.316; 4.241), P = 0.004] was associated with a narrower CRAE. In young healthy adults, masked hypertension was associated with retinal arteriolar narrowing, thereby reflecting early microvascular alterations known to predict cardiovascular outcomes in later life.

The Night Effect of Anger: Relationship with Nocturnal Blood Pressure Dipping

INTRODUCTION

The circadian pattern of blood pressure is characterized by a physiological drop occurring after sleep onset. The alteration of this phenomenon (non-dipping, extreme dipping, or reverse dipping) is associated with an increased cardiovascular risk. Besides altered autonomic and endocrine circadian rhythms, psychological aspects seem to play a role in this modification. However, the few studies that have analyzed the influence of psychological dimensions on the dipping phenomenon have reported inconsistent results. This study aimed to examine the relationship between anger expression and blood pressure (BP) dipping.

METHODS

We obtained 24 h ambulatory BP measurements from 151 participants and used them to define three groups according to their dipping status: Dippers (N = 65), Non-Dippers (N = 42), and Extreme Dippers (N = 44). Sociodemographic and anamnestic information was collected, and the State-Trait Anger Expression Inventory was used to assess anger.

RESULTS

Analysis of variance evidenced significant higher scores for Trait Anger Temperament and Anger Expression in Extreme Dippers than in both Dippers and Non-Dippers. However, after controlling for confounding variables, there was no significant relationship with trait anger, and only the result concerning the suppression of anger was confirmed.

CONCLUSIONS

These findings suggest that the analysis of some psychological factors, such as anger, could be necessary to better understand differences in nocturnal BP alterations. Trait anger and suppression of anger may contribute to the description and classification of patients who exhibit a maladaptive dipping phenomenon. However, modifiable (i.e., cigarette consumption) and unmodifiable (i.e., age) risk factors appear to mediate this relationship. Although further studies are necessary to explore this association, these results highlight that some aspects of anger can represent risk factors or markers of maladaptive modulation of the dipping phenomenon.

QTc Interval Predicts Disturbed Circadian Blood Pressure Variation

Background

The relationship between electrocardiographic evaluation and circadian blood pressure (BP) variation in young and middle-aged hypertensive patients remains unknown.

Methods

A total of 171 hypertensive patients were included in the study. First, patients were divided into a young and middle-aged group and an elderly group. The two groups were then separately classified into three subgroups on the basis of circadian variation of BP as dippers, non-dippers and reverse-dippers. The electrocardiographic evaluation was calculated from 12-lead electrocardiography (ECG).

Results

QTc intervals were shortest in the dippers and longest in the reverse-dippers in the young and middle-aged group (QTc dipper: 416.53±18.37ms; non-dipper: 438.30±29.71ms; reverse-dipper: 444.93±25.47ms; for dipper vs non-dipper, and dipper vs reverse-dipper P<0.05). QTc interval was found to be an independent risk factor for the non-dipper BP pattern (Odds ratio 1.049; 95% CI 1.01-1.089; P=0.012) and reverse-dipper BP pattern (Odds ratio 1.051; 95% CI 1.007-1.098; P=0.023) in young and middle-aged hypertensive patients. No significant differences in other ECG parameters were found among the three subgroups in the young and middle-aged group.

Conclusion

Our study suggested that QTc interval might serve as a risk factor for non-dipper BP pattern and reverse-dipper BP pattern in young and middle-aged hypertensive patients.

Associations of awake and asleep blood pressure and blood pressure dipping with abnormalities of cardiac structure: the Coronary Artery Risk Development in Young Adults study

OBJECTIVES

To evaluate the associations of high awake blood pressure (BP), high asleep BP, and nondipping BP, determined by ambulatory BP monitoring (ABPM), with left ventricular hypertrophy (LVH) and geometry.

METHODS

Black and white participants (n = 687) in the Coronary Artery Risk Development in Young Adults study underwent 24-h ABPM and echocardiography at the Year 30 Exam in 2015-2016. The prevalence and prevalence ratios of LVH were calculated for high awake SBP (≥130 mmHg), high asleep SBP (≥110 mmHg), the cross-classification of high awake and asleep SBP, and nondipping SBP (percentage decline in awake-to-asleep SBP < 10%). Odds ratios for abnormal left ventricular geometry associated with these phenotypes were calculated.

RESULTS

Overall, 46.0 and 49.1% of study participants had high awake and asleep SBP, respectively, and 31.1% had nondipping SBP. After adjustment for demographics and clinical characteristics, high awake SBP was associated with a prevalence ratio for LVH of 2.79 [95% confidence interval (95% CI) 1.63-4.79]. High asleep SBP was also associated with a prevalence ratio for LVH of 2.19 (95% CI 1.25-3.83). There was no evidence of an association between nondipping SBP and LVH (prevalence ratio 0.70, 95% CI 0.44-1.12). High awake SBP with or without high asleep SBP was associated with a higher odds ratio of concentric remodeling and hypertrophy.

CONCLUSION

Awake and asleep SBP, but not the decline in awake-to-asleep SBP, were associated with increased prevalence of cardiac end-organ damage.

Neurogenic Orthostatic Hypotension in Parkinson Disease: A Primer

Parkinson disease (PD) is associated with a variety of motor and non-motor clinical manifestations, including cardiovascular autonomic dysfunction. Neurogenic orthostatic hypotension (nOH) is a potentially serious manifestation of cardiovascular sympathetic failure that occurs in approximately 30% of patients with PD. Here we review the pathophysiology and effects of the condition as well as treatment considerations for patients with PD and nOH. Screening for nOH using orthostatic symptom questionnaires, orthostatic blood pressure measurements, and specialized autonomic testing is beneficial for the identification of symptomatic and asymptomatic cases because cardiac sympathetic denervation and nOH can occur even at early (premotor) stages of PD. Symptoms of nOH, such as orthostatic lightheadedness, in patients with PD, have been shown to adversely affect patient safety (with increased risk of falls) and quality of life and should prompt treatment with non-pharmacologic and, occasionally, pharmacologic measures. Patients with nOH are also at increased risk of supine hypertension, which requires balancing various management strategies. FUNDING: Lundbeck (Deerfield, IL).

Nocturnal systolic blood pressure pattern of type 2 diabetic hypertensive men with erectile dysfunction: a cross sectional study from Northern Sri Lanka

Objective

This small scale cross-sectional study was done to identify the common systolic blood pressure pattern (dipping or non-dipping) among type 2 diabetic men with coexisting hypertension and erectile dysfunction(ED). A recent study in the same setting showed that prevalence of ED was high among diabetic men and co-existing hypertension was identified as an independent risk factor. There was a postulation about an association between ED and non-dipping nocturnal blood pressure pattern. So ambulatory blood pressure measurements (ABPM) was obtained for participants to test this prediction. Data was analysed using SPSS 25 Version.

Results

Among 29 participants who underwent ABPM, 21 showed non-dipping pattern of nocturnal systolic blood pressure (72.4%; CI 54.3–86.3). Mean SBP of participants was 125.55 +_14.1 and Mean DBP was 81.5 + _12.82. There was no statistical difference observed in mean SBP and DBP between patients with dipping nocturnal SBP and non-dipping pattern (P > 0.05). Variability of SBP was high among the participants (Mean SD-11.96 +/_2.74) and DBP also showed relatively high variability (SD-9.28 +/_2.9). Mean dipping percentage of the SBP during sleep was 5.54 +/_6.66. A significant difference in heart rate (HR) between patients with non-dipping and dipping pattern was noted (P-0.034).

Influence of circadian blood pressure alterations on serum SCUBE-1 and soluble CD40 ligand levels in patients with essential hypertension

BACKGROUND

Dipper and non-dipper hypertension are different clinical forms of essential hypertension. In this study, the effect of circadian blood pressure changes on serum SCUBE-1 and soluble CD40 ligand (sCD40L) levels was investigated in patients with hypertension.

METHODS

A total of 100 participants aged 23-89 years were included in the study. Patients with essential hypertension were followed up by ambulatory blood pressure measurement.

RESULTS

Serum SCUBE1 levels were significantly higher in the non-dipper group than in the normal group (P < 0.001). Dipper and non-dipper patients had significantly higher serum sCD40L levels when compared to the normal group (P = 0.048 and P = 0.035, respectively). We also found a positive correlation between SCUBE1, sCD40L levels and 24-hour mean systolic blood pressure levels (r: 0.232, p: 0.034 and r: 0.241, p: 0.027, respectively).

CONCLUSION

Serum SCUBE1 and sCD40L levels were higher in hypertensive patients than normal participants. Serum SCUBE1 levels were higher in patients with non-dipper compared to other participants.

Normotensive patients with obstructive sleep apnoea: changes in 24-h ambulatory blood pressure monitoring with continuous positive airway pressure treatment

BACKGROUND

Continuous positive airway pressure (CPAP) treatment reduces blood pressure (BP) in obstructive sleep apnoea (OSA) and hypertensive patients, but there is a lack of data about the effects of CPAP on the BP in normotensive patients.

OBJECTIVE

The aim of the study was to evaluate BP changes in normotensive OSA individuals receiving CPAP treatment.

METHODS

We selected 131 normotensive outpatients with an apnoea/hypopnoea index (AHI) greater than 15 events/hour who required CPAP treatment. All patients underwent a sleep study and 24-h ambulatory BP monitoring (ABPM) at baseline and after 6 months. In addition, the patients were assessed for the presence of baseline masked hypertension, defined as office BP less than 140/90 mmHg and increased BP on 24-h ABPM (mean 24-h BP ≥130/80 mmHg).

RESULTS

After 6 months of CPAP treatment, a mild reduction in all 24-h ABPM variables was observed, but only the mean 24-h DBP [-1.39 mmHg, 95% confidence interval (95% CI), -2.50 to -0.27], mean daytime DBP (-1.39 mmHg, 95% CI -2.56 to -0.22) and the mean 24-h ambulatory BP (-1.80 mmHg, 95% CI, -3.16 to -0.44) reached statistical significance. The reduction was primarily due to BP changes in individuals with masked hypertension who displayed a mean BP reduction of -4.78 mmHg (-7.25 to -2.30 mmHg). Consistent with a circadian BP pattern, a reduction in mean nocturnal BP of -4.73 mmHg (-7.39 to -2.06 mmHg) was observed at 6 months in nondippers; in contrast, the mean nocturnal BP in dippers increased by 2.61 mmHg (0.60-4.62 mmHg).

CONCLUSION

Our findings suggest that the CPAP effects may be different in normotensive outpatients depending on the presence of undiagnosed masked hypertension and the dipping pattern. Therefore, it is important to consider measuring ABPM in this type of patient.

Relationship Between Outpatient Clinic and Ambulatory Blood Pressure Measurements and Mortality

PURPOSE OF REVIEW

This review aims to summarize and discuss the relationship between outpatient clinic and ambulatory blood pressure (BP) measurements and cardiovascular morbidity and mortality.

RECENT FINDINGS

Contemporary clinical practice guidelines worldwide recommend ambulatory blood pressure monitoring (ABPM) to confirm the diagnosis of hypertension. Recent epidemiological studies and systematic reviews showed ABPM predicts cardiovascular events and mortality independent of clinic BP. Ambulatory BP appears to be prognostically superior to clinic BP. ABPM characterizes BP phenotypes that would not have otherwise identified with clinic BP measurement only. Identification of white coat hypertension, which carries a prognosis almost similar to normotension, and masked hypertension, which carries a prognosis almost similar to sustained hypertension, can be accomplished only by ABPM. Randomize controlled trials to assess the cardiovascular effects of hypertensive patients managed with ABPM vs. clinic BP measurement and cost-effective studies of ABPM are warranted.

A Novel Diabetic Mouse Model for Real-Time Monitoring of Clock Gene Oscillation and Blood Pressure Circadian Rhythm

Diabetic patients have an increased prevalence of blood pressure (BP) circadian rhythm disruption, which is associated with an increased risk of target organ damage and detrimental cardiovascular events. Limited information is available regarding the role of clock genes in the disruption of BP circadian rhythm in diabetes due to the lack of a diabetic animal model that allows real-time monitoring of clock gene oscillation. Here, we generated a novel diabetic db/db-mPer2^Luc mouse model by crossing type 2 diabetic db/db mice with mPer2^Luc knock-in mice. The daily rhythms of BP, heart rate, locomotor activity, and food and water intake were acquired by radiotelemetry or using metabolic chambers. The daily oscillation of mPer2 bioluminescence was recorded by LumiCycle in real-time in tissue explants and using the IVIS system in vivo. Our results show that db/db-mPer2^Luc mice are obese, diabetic, and glucose intolerant. The db/db-mPer2^Luc mice displayed a compromised BP daily rhythm, which was associated with disrupted daily rhythms in baroreflex sensitivity, locomotor activity, and metabolism, but not heart rate or food and water intake. The phase of the mPer2 daily oscillation was advanced to different extents in the explanted peripheral tissues from db/db-mPer2^Luc mice relative to control mice. In contrast, no phase shift was detected in mPer2 daily oscillations in the explanted SCN. Moreover, advanced phase shift of the mPer2 daily oscillation was detected in the liver, kidney and submandibular gland in vivo of db/db-mPer2^Luc mice. In conclusion, the diabetic db/db-mPer2^Luc mouse is a novel animal model that allows real-time monitoring of mPer2 circadian rhythms ex vivo and in vivo. The results from db/db-mPer2^Luc mice suggest that the desynchrony of mPer2 daily oscillation in peripheral tissues contributes to the loss of BP daily oscillation in diabetes.

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.

Sleep Disturbances as a Risk Factor for Stroke

Sleep, a vital process of human being, is carefully orchestrated by the brain and consists of cyclic transitions between rapid eye movement (REM) and non-REM (NREM) sleep. Autonomic tranquility during NREM sleep is characterized by vagal dominance and stable breathing, providing an opportunity for the cardiovascular-neural axis to restore homeostasis, in response to use, distress or fatigue inflicted during wakefulness. Abrupt irregular swings in sympathovagal balance during REM sleep act as phasic loads on the resting cardiovascular system. Any causes of sleep curtailment or fragmentation such as sleep restriction, sleep apnea, insomnia, periodic limb movements during sleep, and shift work, not only impair cardiovascular restoration but also impose a stress on the cardiovascular system. Sleep disturbances have been reported to play a role in the development of stroke and other cardiovascular disorders. This review aims to provide updated information on the role of abnormal sleep in the development of stroke, to discuss the implications of recent research findings, and to help both stroke clinicians and researchers understand the importance of identification and management of sleep pathology for stroke prevention and care.

Heart rate phenotypes and clinical correlates in a large cohort of adults without sleep apnea

BACKGROUND

Normal sleep is associated with typical physiological changes in both the central and autonomic nervous systems. In particular, nocturnal blood pressure dipping has emerged as a strong marker of normal sleep physiology, whereas the absence of dipping or reverse dipping has been associated with cardiovascular risk. However, nocturnal blood pressure is not measured commonly in clinical practice. Heart rate (HR) dipping in sleep may be a similar important marker and is measured routinely in at-home and in-laboratory sleep testing.

METHODS

We performed a retrospective cross-sectional analysis of diagnostic polysomnography in a clinically heterogeneous cohort of n=1047 adults without sleep apnea.

RESULTS

We found that almost half of the cohort showed an increased HR in stable nonrapid eye movement sleep (NREM) compared to wake, while only 13.5% showed a reduced NREM HR of at least 10% relative to wake. The strongest correlates of HR dipping were younger age and male sex, whereas the periodic limb movement index (PLMI), sleep quality, and Epworth Sleepiness Scale (ESS) scores were not correlated with HR dipping. PLMI was however significantly correlated with metrics of impaired HR variability (HRV): increased low-frequency power and reduced high-frequency power. HRV metrics were unrelated to sleep quality or the ESS value. Following the work of Vgontzas et al, we also analyzed the sub-cohort with insomnia symptoms and short objective sleep duration. Interestingly, the sleep-wake stage-specific HR values depended upon insomnia symptoms more than sleep duration.

CONCLUSION

While our work demonstrates heterogeneity in cardiac metrics (HR and HRV), the population analysis suggests that pathological signatures of HR (nondipping and elevation) are common even in this cohort selected for the absence of sleep apnea. Future prospective work in clinical populations will further inform risk stratification and set the stage for testing interventions.

What's new in paediatric hypertension?

Paediatric hypertension predisposes to hypertension and cardiovascular disease in adult life. Despite clear guidelines, there remains a lack of screening. Diagnosis remains challenging given the high rate of false-positive high blood pressure (BP) readings at a single visit; thus, multiple visits are required to confirm the diagnosis. Depending on the normative data sets used, hypertension in overweight and obese children can be underestimated by up to 20%. Specific BP targets are required for subgroups such as adolescents, children with chronic kidney disease (CKD) and type 1 diabetes. High dietary salt intake is a risk factor for cardiovascular disease. Given the rise in processed food consumption, children in developed nations are likely to benefit from salt restriction at a population-based level.

Blood pressure profile is associated with microalbuminuria and retinopathy in hypertensive nondiabetic patients

BACKGROUND

Target organ damage is important for global cardiovascular risk assessment. The aim of this study was to explore the association between the blood pressure profile and end-organ damage in a hypertensive non-diabetic cohort.

METHODS

A total of 560 consecutive hypertensive nondiabetic patients (mean age: 58.2 ± 13.3 years, 221 men) were included in the study. All patients underwent thorough physical examination including fundoscopic examination. First morning urine samples were obtained from each patient and measurement of the albumin-to-creatinine ratio in first morning urine collection samples was used for diagnosis of microalbuminuria. All patients underwent a 24-h ambulatory blood pressure monitoring and were grouped as dippers and non-dippers according to the presence or absence of >10% decrease in blood pressure during the night, respectively.

RESULTS

The non-dipper group consisted of 247 patients with a non-dipper blood pressure profile, 31 patients with reverse dipping and 4 patients with extreme dipping. Non-dipper patients were significantly older. Coronary artery disease, cerebrovascular disease, hypertensive retinopathy and microalbuminuria were significantly more prevalent in the non-dipper patients. Non-dipping hypertension increased the risk of hypertensive retinopathy by 1.89 times (95% confidence interval, CI:1.35-2.65, p < 0.001) and the risk of microalbuminuria by 2.23 times (95% CI:1.49-3.33, p < 0.001). Non-dipping hypertension was still significantly associated with hypertensive retinopathy and microalbuminuria when adjusted by age and sex.

CONCLUSION

Non-dipping hypertension was associated with increased risk of hypertensive retinopathy and microalbuminuria. Blood pressure profiles should also be considered in assessing the risk for hypertensive patients.

Evaluation of Daily Blood Pressure Alteration in Subclinical Hypothyroidism

BACKGROUND

Subclinical hypothyroidism is the most common thyroid dysfunction in the general population. The relationship between overt thyroid dysfunction and hypertension is generally understood. Besides high blood pressure, non-dipper hypertension is known to increase cardiovascular risk. Our aim is to investigate daily blood pressure changes and the frequency of non-dipping patterns in patients with subclinical hypothyroidism.

METHODS

Forty-nine patients without hypertension with subclinical hypothyroidism were compared with 50 healthy sex- and age-matched controls using ambulatory blood pressure monitoring.

RESULTS

Thyroid-stimulating hormone (TSH) levels were significantly higher in the subclinic hypothyroidism group, and there was no difference between free triiodothyronine (FT3) and free thyroxine (FT4) levels which could be predicted as a result of the study design. Levels of mean diastolic, daytime diastolic, nighttime diastolic and nighttime systolic blood pressure were significantly higher in the subclinic hypothyroidism group (p = 0.001 for mean, daytime and nighttime diastolic and p = 0.01 for nighttime systolic). Diastolic non-dipping occurred more frequently in the subclinic hypothyroidism group [subclinical hypothyroidism group 24 patients (49%), control group 13 patients (26%), p = 0.01]. On multivariate analysis, subclinical hypothyroidism was independently associated with diastolic non-dipping (95% confidence interval 1.162-8.053, odds ratio 1.182, p = 0.024).

CONCLUSIONS

Our study found that both the frequency of diastolic non-dipping pattern and diastolic blood pressure increase with subclinical hypothyroidism. Therfore, it would appear that searching for non-dipping pattern can add valuable information for patients with subclinical hypothyroidism.

Relationship between Sleep Duration and Risk Factors for Stroke

Stroke is a leading cause of death and disability worldwide. While various risk factors have been identified, sleep has only been considered a risk factor more recently. Various epidemiologic studies have associated stroke with sleep such as sleep duration, and laboratory and clinical studies have proposed various underlying mechanisms. The pathophysiology is multifactorial, especially considering sleep affects many common risk factors for stroke. This review aims to provide an outline of the effect of sleep duration on common stroke risk factors. Appropriate sleep duration, especially in patients who have stroke risk factors, and increasing awareness and screening for sleep quality may contribute to primary prevention of stroke.

Novel developments in differentiating the role of renal and intestinal sodium hydrogen exchanger 3

The Na⁺/H⁺ exchanger isoform 3 (NHE3) facilitates Na⁺ absorption and H⁺ secretion and is expressed in the intestine, proximal tubule, and thick ascending limb of the kidney. While the function of NHE3 for Na⁺ and [Formula: see text](re)absorption has been defined using conventional NHE3 knockout mice (NHE3^-/-), the recent generation of conditional NHE3 knockout mice started to give critical new insight into the role of this protein by allowing for temporal and spatial control of NHE3 expression. For example, in contrast to NHE3^-/- mice, knockout of NHE3 in the S1 and S2 segments of the proximal tubule or along the entire tubule/collecting duct does not cause any lethality. Nonabsorbable NHE3 inhibitors have been developed, and preclinical as well as clinical trials indicate possible pharmacological use in fluid overload, hypertension, chronic kidney disease, hyperphosphatemia, and constipation. Some of the therapeutic considerations seem to be directly related to the pharmacodynamic properties of these drugs; however, little is known about the effects of these nonabsorbable NHE3 inhibitors on intestinal phosphate transport and the mechanisms so far remain elusive. This review focuses on novel findings of NHE3 in the intestine and the kidney as well as novel drug developments targeting NHE3.

Dietary sodium and nocturnal blood pressure dipping in normotensive men and women

Impaired nocturnal blood pressure (BP) dipping (i.e., <10% decline in nocturnal BP) is associated with an increased risk of cerebrovascular and cardiovascular diseases. Excess sodium has been shown to impair BP regulation and increase cardiovascular disease risk, yet few studies have assessed the influence of dietary sodium on nocturnal dipping in normotensive adults. The purpose of this study was to determine the effects of dietary sodium on BP dipping in normotensive men and women. Eighty healthy normotensive adults participated in a controlled feeding study (men: n=39, 34±2 yrs; women: n=41, 41±2 yrs). Participants consumed a standardized run-in 100 mmol sodium·day⁻¹ diet for 7 days, followed by 7 days of low sodium (LS; 20 mmol·day⁻¹) and high sodium (HS; 300 mmol·day⁻¹) diets in random order. On the final day of each diet, subjects wore a 24h ambulatory BP monitor, collected a 24h urine sample, and provided a blood sample. During the run-in diet, 24h urinary sodium excretion was 79.4±5.1 mmol·24h⁻¹ in men and 85.3±5.5 mmol·24h⁻¹ in women (p>0.05). Systolic BP dipping was not different between men (11.4±1.0%) and women (11.2±0.9%) (p>0.05). During the HS diet, 24h urinary sodium excretion increased compared to the LS diet in men (LS=31.7±4.6 mmol·24h⁻¹ vs. HS=235.0±13.9 mmol·24h⁻¹, p<0.01) and women (LS=25.8±2.2 mmol·24h⁻¹ vs. HS=234.7±13.8 mmol·24h⁻¹, p<0.01). Despite this large increase in sodium intake and excretion, systolic BP dipping was not blunted in men (LS=8.9±1.0% vs. HS=9.4±1.2%, p>0.05) or women (LS=10.3±0.8% vs. HS=10.5±0.8%, p>0.05). Among normotensive men and women, HS does not blunt nocturnal BP dipping.

Night-time blood pressure and target organ damage: a comparative analysis of absolute blood pressure and dipping status

BACKGROUND

The prognostic significance of abnormal circadian blood pressure (BP) patterns is well established. Research to date has focused on both nocturnal dipping and absolute night-time BP levels; however, which of these variables should be the primary target for therapy remains unclear. The aim of this study is to determine whether dipping status or absolute night-time BP levels have a stronger association with subclinical target organ damage (TOD).

METHODS

The Mitchelstown Cohort was established to examine cardiovascular health in an adult population sample recruited from primary care. Night-time BP was categorized by dipping status. Subclinical TOD was defined as Cornell Product left ventricular hypertrophy (LVH) voltage criteria on ECG and urine albumin : creatinine ratio (ACR) at least 1.1 mg/mmol. Multivariable logistic regression analysis was used to assess the association between night-time BP and TOD.

RESULTS

Of 2047 participants, 1207 (response rate 59%), underwent 24-h ambulatory BP monitoring. We excluded 161 studies due to incomplete data. Of 1046 participants, 178 (17%) had evidence of TOD. Each 10-mmHg rise in night-time SBP increased the odds of TOD. Odds ratio (OR) ACR at least 1.1 mg/mmol 1.5 [95% confidence interval (95% CI) 1.2-1.8] and OR LVH 1.4 (95% CI 1.1-1.8).

CONCLUSION

Absolute BP level rather than dipping status may be a superior early marker of risk associated with night-time BP. Interventional studies are required to determine whether there is a benefit in specifically targeting absolute night-time BP levels to prevent clinically important outcomes.

Hypertension in chronic kidney disease: role of ambulatory blood pressure monitoring

Children with chronic kidney disease have a markedly increased risk of cardiovascular morbidity and children with end stage renal disease have an estimated 30 times greater risk of cardiovascular mortality than the general pediatric population. In adults, the link between hypertension and cardiovascular disease is well-documented but that association has not been so readily apparent in children with chronic kidney disease. This may be in part because the early changes in blood pressure that occur in these patients do not necessarily manifest with changes in casual blood pressure measurements. Ambulatory blood pressure monitoring, with its ability to gather multiple readings both during the normal activities of the day and the night, is felt to be a more veritable measure of blood pressure. Its use in children has been hampered by limited data on normative values and difficulties in blood pressure classification, while its use in adults is ever expanding. However, with an increasing number of studies in children with chronic kidney disease, ambulatory blood pressure has revealed a greater prevalence of abnormal findings in this population and has been shown to better predict cardiovascular risk than current standards. Two large multi-center studies in Europe and North America have revealed even greater utility of ambulatory blood pressure measures in this population. It is hoped that continued use of ambulatory monitoring in children will help overcome some of its perceived limitations while also validating its use in those at high risk of cardiovascular morbidity.

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.

Aortic dissection in children and adolescents with Turner syndrome: risk factors and management recommendations

There is a general lack of awareness of the risk of aortic dissection in Turner syndrome (TS) from both patients with TS and their physicians. Patients often ignore symptoms for up to 24 h before seeking medical advice, significantly increasing their risk of death. A clinical profile of those at risk of dissection is emerging and includes the presence of congenital heart defects, aortic dilatation and hypertension. MRI has revolutionised the visualisation of cardiovascular anatomy in TS but remains underutilised, especially in children and adolescents, and there is currently little guidance on blood pressure (BP) assessment or hypertension management. Children and adolescents with TS at risk of dissection could be easily identified by timely imaging and BP assessment. This would allow medical management or surgical intervention to be put in place to reduce the risk of this major, and often fatal, complication. Since guidance is lacking, we have reviewed the literature on the risk factors for dissection in TS during childhood and adolescence, and make recommendations on the assessment and management of these patients.