The role of blood pressure variability in end-organ damage

Impact of amlodipine on clinical outcomes for heart failure in patients with dilated cardiomyopathy: a Korean nationwide cohort study

Introduction

Amlodipine, widely used as a first-line treatment for hypertension, has inconclusive clinical evidence regarding its efficacy in patients with heart failure. This retrospective cohort study aimed to investigate the clinical effectiveness of amlodipine treatment after hospitalization for heart failure in patients with dilated cardiomyopathy (DCMP).

Methods

A total of 20,851 patients who were diagnosed with DCMP and admitted for heart failure between 2005 and 2016 according to Korean nationwide medical insurance service database were enrolled. Amlodipine use was defined as its prescription at the time of discharge and for at least 180 days within a year. The primary outcome was all-cause death, and the secondary outcome was heart failure rehospitalization during a 5-year period. The outcomes between patients who received amlodipine (n = 6,798) and those who did not (n = 14,053) were compared.

Results

During the 5-year follow-up, the group treated with amlodipine exhibited a significantly lower risk of all-cause death and heart failure rehospitalization than the group not treated with amlodipine [all-cause death: adjusted hazard ratio (HR): 0.64, 95% confidence interval (CI): 0.59-0.70, p < 0.001; cardiovascular death: adjusted HR: 0.71, 95% CI: 0.62-0.81, p < 0.001; heart failure rehospitalization: adjusted HR: 0.92, 95% CI: 0.86-0.98, p = 0.006]. In a subgroup analysis, amlodipine had a significant impact on decreasing all-cause mortality in older adults, those with a higher systolic blood pressure, and those with a lower Charlson Comorbidity Index.

Conclusion

In summary, amlodipine use after hospitalization for heart failure in patients with DCMP was associated with a lower risk of all-cause death and readmission for heart failure.

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.

Impact of oscillometric measurement artefacts in ambulatory blood pressure monitoring on estimates of average blood pressure and of its variability: a pilot study

OBJECTIVE

Ambulatory blood pressure monitoring (ABPM) plays an important role in the diagnosis of hypertension. However, methodological factors and the measurement conditions affect the results and may lead to incorrect classification of the patient. We performed a pilot study to evaluate the impact of oscillometric measurement artefacts on ABPM-derived variables.

METHODS

Four classes of artefacts have been detected: motor activity artefacts, cuff errors, cardiovascular arousals, and arrhythmias. The data consisted of uncorrected measurements (all data), corrected measurements (all artefact free data), and artefact affected data.

RESULTS

A total of 30 individuals (9 female/21 male), aged between 36 and 86 years, mean: 65.5 (standard deviation: 9.5) were included in the study. The average blood pressure (BP) was higher in artefacts-affected measurements compared the artefact-free measurements both for systolic (4.6 mmHg) and diastolic (1.3 mmHg) measurements. Further, artefact-affected systolic BP (SBP) was 6.4 mmHg higher than artefact-free measurements during daytime. Nocturnal measurements showed no artefact-depended differences. Individual comparisons yielded that 23% of the participants crossed the threshold for BP classification for either 24-h, daytime or nocturnal hypertension when comparing uncorrected and artefact-free measurements. Dipping classification changed within 24% of participants. BP variability was 21 and 12% higher for SPB and DBP, respectively, during daytime. These differences were even higher (27% for SBP and 21% for DPB) during night-time.

CONCLUSION

The study reveals that measurement artefacts are frequently present during cuff-based ABPM and do relevantly affect measurement outcome. Exclusion of measurement artefacts is a promising approach to improving cuff-based ABPM accuracy.

The relationship between nondipper hypertension and triglyceride glucose index

Nondipper hypertensive patients have an increased incidence of damage to end organs, including the brain, heart, and kidney, and a worse cardiovascular prognosis. The triglyceride glucose (TyG) index is a reliable indicator of insulin resistance (IR) and is closely related to the traditional risk factors of cardiovascular disease. To the best of our knowledge, whether there is a relationship between the TyG index and impaired diurnal blood pressure (BP) has not been investigated. This study aimed to compare the TyG index between normotensive, nondipper, and dipper hypertensive patients. A total of 1037 patients grouped according to the results of ambulatory BP monitoring were included, with group 1 including dipper hypertensive ( n = 368), group 2 including nondipper hypertensive ( n = 496), and group 3 including normotensive control ( n = 173) patients. In both the univariate and multivariate logistic regression analyses, TyG index [odds ratio (OR), 4.656; 95% confidence interval (CI), 3.014-7.193; P < 0.001], age (OR, 1.011; 95% CI, 1.002-1.021; P = 0.018), and glomerular filtration rate (GFR) (OR, 0.979; 95% CI, 0.971-0.987; P < 0.001) were independent predictors of nondipper hypertension (HT). In the ROC analysis, a TyG index cutoff value of at least 4.74 predicted nondipper hypertensive patients with a sensitivity of 59.7%, and a specificity of 59.9% [area under the curve = 0.647 (0.614-0.680); 95% CI; P < 0.001]. We showed that TyG index, age, and GFR are independent predictors in patients with nondipper HT. TyG index, a simple, cost-effective, and rapid tool can predict the nondipper pattern in essential HT.

Hyperuricemia during Pregnancy Leads to a Preeclampsia-Like Phenotype in Mice

Hyperuricemia is a common feature in pregnancies compromised by pre-eclampsia, a pregnancy disease characterized by hypertension and proteinuria. The role of uric acid in the pathogenesis of pre-eclampsia remains largely unclear. The aim of this study was to investigate the effect of elevated uric acid serum levels during pregnancy on maternal blood pressure and neonatal outcome using two different murine knockout models. Non-pregnant liver-specific GLUT9 knockout (LG9KO) mice showed elevated uric acid serum concentrations but no hypertensive blood pressure levels. During pregnancy, however, blood pressure levels of these animals increased in the second and third trimester, and circadian blood pressure dipping was severely altered when compared to non-pregnant LG9KO mice. The impact of hyperuricemia on fetal development was investigated using a systemic GLUT9 knockout (G9KO) mouse model. Fetal hyperuricemia caused distinctive renal tissue injuries and, subsequently an impaired neonatal growth pattern. These findings provide strong evidence that hyperuricemia plays a major role in the pathogenesis of hypertensive pregnancy disorders such as pre-eclampsia. These novel insights may enable the development of preventive and therapeutic strategies for hyperuricemia-related diseases.

Systemic Immune-Inflammation Index: A Novel Predictor for Non-dipper Hypertension

Introduction

The non-dipper hypertension (HT) pattern is associated with more end-organ damage and cardiovascular events than is dipper HT. Inflammation is widely established to play a role in the pathophysiology of HT. Recently, a new inflammatory and prognostic marker called the systemic immune-inflammation index (SII) has emerged. Our goal is to determine whether there is a relationship between non-dipper HT and SII.

Methods

Our study is a single-center retrospective and ninety-one patients with HT were included. All patients were analyzed with simultaneous 24-hour ambulatory blood pressure monitoring and laboratory parameters. Thirty-five patients had dipper HT while 56 patients had non-dipper HT. SII was calculated according to neutrophil, platelet, and lymphocyte counts.

Results

The median age was 48 (45-61 interquartile range (IQR)) in the non-dipper HT group, whereas it was 54 (44-64 IQR) in the dipper HT group. Although the neutrophil level, neutrophil-lymphocyte ratio, platelet lymphocyte ratio, SII, sleeping systolic blood pressure (BP), and sleeping diastolic BP were higher (p=0.020, p=0.041, p=0.046, p=0.019, p<0.001, and p=0.001, respectively) in the non-dipper HT group, the lymphocyte level was lower (p=0.040). A multivariate logistic regression model shows that SII (odds ratio (OR)=1.023, 95% confidence interval (CI)=1.002-1.112, p=0.012) may be an independent predictor of non-dipper HT.

Conclusion

Our study showed that the SII level was higher in the non-dipper HT patient group than in the dipper HT group. Furthermore, SII was an independent predictor of non-dipper HT. The high SII value in hypertension patients can be used as an early warning parameter to identify non-dipper HT patients.

The B-Score is a novel metric for measuring the true performance of blood pressure estimation models

We aimed to develop and test a novel metric for the relative performance of blood pressure estimation systems (B-Score). The B-Score sets absolute blood pressure estimation model performance in contrast to the dataset the model is tested upon. We calculate the B-Score based on inter- and intrapersonal variabilities within the dataset. To test the B-Score for reliable results and desired properties, we designed generic datasets with differing inter- and intrapersonal blood pressure variability. We then tested the B-Score’s real-world functionality with a small, published dataset and the largest available blood pressure dataset (MIMIC IV). The B-Score demonstrated reliable and desired properties. The real-world test provided allowed the direct comparison of different datasets and revealed insights hidden from absolute performance measures. The B-Score is a functional, novel, and easy to interpret measure of relative blood pressure estimation system performance. It is easily calculated for any dataset and enables the direct comparison of various systems tested on different datasets. We created a metric for direct blood pressure estimation system performance. The B-Score allows researchers to detect promising trends quickly and reliably in the scientific literature. It further allows researchers and engineers to quickly assess and compare performances of various systems and algorithms, even when tested on different datasets.

The association between nondipper pattern and perioperative hypertension in patients with controlled hypertension

BACKGROUND

Perioperative hypertension is a frequent complication even in preoperatively normotensive or controlled hypertensive patients and there is a lack of data regarding the effect of nondipping pattern on perioperative hypertension.

OBJECTIVE

In this study, we aimed to investigate the possible effect of nondipping blood pressure pattern on the risk of perioperative hypertension.

MATERIALS AND METHODS

234 hypertensive patients who underwent surgery with general anesthesia were evaluated prospectively. The study enrolled patients with well-controlled preoperative blood pressure. The 24-h ambulatory blood pressure monitoring results were used to classify patients as dippers and nondippers. Perioperative hypertension is defined as a systolic/diastolic arterial blood pressure greater than or equal to 160/90 mmHg or systolic blood pressure elevated by more than 20% from the patient's baseline level for more than 15 min perioperatively.

RESULTS

There were 61 (26%) nondipper patients [mean age: 62.1 ± 7.1 years, 25 (40.9%) men] and 173 (74%) dipper patients [mean age: 61.4 ± 8.1 years, 83 (47.9%) men]. In the nondipper group, perioperative hypertension was observed in 31 (51.3%) patients, whereas in the dipper group, 33 (19.3%) patients experienced a hypertensive attack (P < 0.001). The independent predictors of perioperative hypertension were the presence of the nondipping pattern [odds ratio (OR) 3.084; 95% confidence interval (CI) 1.831-5.195; P < 0.001], the presence of diabetes mellitus (OR 2.059; 95% CI 1.215-3.490; P = 0.007), and the number of drugs (OR 2.317; 95% CI 1.102-5.097; P = 0.027).

CONCLUSION

The frequency of perioperative hypertension was higher in preoperative normotensive and known hypertensive patients who were identified as nondippers. In addition, diabetes mellitus and number of drugs were found to be predictors of perioperative hypertension.

The Paraventricular Nucleus of the Hypothalamus in Control of Blood Pressure and Blood Pressure Variability

The paraventricular nucleus (PVN) is a highly organized structure of the hypothalamus that has a key role in regulating cardiovascular and osmotic homeostasis. Functionally, the PVN is divided into autonomic and neuroendocrine (neurosecretory) compartments, both equally important for maintaining blood pressure (BP) and body fluids in the physiological range. Neurosecretory magnocellular neurons (MCNs) of the PVN are the main source of the hormones vasopressin (VP), responsible for water conservation and hydromineral balance, and oxytocin (OT), involved in parturition and milk ejection during lactation. Further, neurosecretory parvocellular neurons (PCNs) take part in modulation of the hypothalamic–pituitary–adrenal axis and stress responses. Additionally, the PVN takes central place in autonomic adjustment of BP to environmental challenges and contributes to its variability (BPV), underpinning the PVN as an autonomic master controller of cardiovascular function. Autonomic PCNs of the PVN modulate sympathetic outflow toward heart, blood vessels and kidneys. These pre-autonomic neurons send projections to the vasomotor nucleus of rostral ventrolateral medulla and to intermediolateral column of the spinal cord, where postganglionic fibers toward target organs arise. Also, PVN PCNs synapse with NTS neurons which are the end-point of baroreceptor primary afferents, thus, enabling the PVN to modify the function of baroreflex. Neuroendocrine and autonomic parts of the PVN are segregated morphologically but they work in concert when the organism is exposed to environmental challenges via somatodendritically released VP and OT by MCNs. The purpose of this overview is to address both neuroendocrine and autonomic PVN roles in BP and BPV regulation.

Dietary sodium and health: How much is too much for those with orthostatic disorders?

High dietary salt (NaCl) increases blood pressure (BP) and can adversely impact multiple target organs including the vasculature, heart, kidneys, brain, autonomic nervous system, skin, eyes, and bone. However, patients with orthostatic disorders are told to increase their NaCl intake to help alleviate symptoms. While there is evidence to support the short-term benefits of increasing NaCl intake in these patients, there are few studies assessing the benefits and side effects of long-term high dietary NaCl. The evidence reviewed suggests that high NaCl can adversely impact multiple target organs, often independent of BP. However, few of these studies have been performed in patients with orthostatic disorders. We conclude that the recommendation to increase dietary NaCl in patients with orthostatic disorders should be done with care, keeping in mind the adverse impact on dietary NaCl in people without orthostatic disorders. Modest, rather than robust, increases in NaCl intake may be sufficient to alleviate symptoms but also minimize any long-term negative effects.

Association of nocturnal subconjunctival hemorrhage and non-dipper blood pressure pattern: A benign clue for serious diseases

PURPOSE

To evaluate the association between non-dipper blood pressure pattern and subconjunctival hemorrhage (SCH).

METHODS

Twenty-seven consecutive patients with nocturnal SCH and 27 age, sex-matched controls were enrolled. Demographic, blood parameters, office blood pressure measurements, 24-h ambulatory blood pressure monitoring (ABPM) were evaluated.

RESULTS

Mean diastolic blood pressure (DBP) for nighttime (65.03 ± 7.1 vs. 70.78 ± 10.5, p: 0.22), mean heart rate for nighttime (64.54 ± 8.26 vs. 69.93 ± 9.85, p: 0.034), Minimum Systolic Blood pressure(SBP) and DBP values for nighttime (92.44 ± 9.72 vs. 99.44 ± 10.66, p:0.015 and 51.15 ± 8.31 vs. 57.7 ± 11.2, p: 0.018) were higher, nocturnal fall ratio of SBP and DBP were significantly lower in the SCH ( + ) group compared to SCH (-) group (5.38 ± 8.39 vs. 10.34 ± 6.08, p: 0.016 and 4.26 ± 8.92 vs. 13.78 ± 6.97, p < 0001 respectively). Ten patients (37%) in the SCH (-) group and 18 patients (66.7%) in the SCH ( + ) group were non-dippers (p: 0.029). Mean daytime SBP and DBP were higher compared to office measurements of 4 patients (14.8%) in the SCH (-) group and 11 patients (40.7%) in the SCH ( + ) group (p: 0.033).

CONCLUSION

SCH had a strong association with non-dipper blood pressure pattern, higher nocturnal heart rate and masked hypertension which are precursors of myocardial infarction, stroke and renal failure. So, SCH should be considered as a clue for serious diseases such as coronary artery disease, myocardial infarction, stroke and patients should be evaluated for ABPM.

Day-To-Day Home Blood Pressure Variability and All-Cause Mortality in a Memory Clinic Population

BACKGROUND

High day-to-day blood pressure variability (BPV) has been associated with an increased risk for cognitive decline and mortality in the general population. Whether BPV is associated with increased all-cause mortality in older people with cognitive impairment is unknown.

OBJECTIVE

To investigate the association between day-to-day home BPV and all-cause mortality in older patients attending a memory clinic.

METHODS

We included 279 patients attending a memory clinic, who measured home blood pressure (BP) for 7 consecutive days in the morning and evening. Within-subject BPV was defined as the variation independent of the mean (VIM). Time-to-death was verified through the Dutch population registry. Cox proportional hazard regression was used. Separate analyses were performed for morning-to-morning and evening-to-evening BPV.

RESULTS

Mean age was 73±9 years, dementia and mild cognitive impairment were diagnosed in 35% and 34% respectively, and mean home BP was 139/79 mmHg. After a mean follow-up of 3.2 years, 52 patients had died. Neither day-to-day systolic nor diastolic VIM were associated with mortality (adjusted hazard ratio [HR] systolic VIM: 0.99, 95% -CI 0.92-1.06, p = 0.770, HR diastolic VIM: 1.04, 95% -CI 0.93-1.17, p = 0.517). When morning and evening measurements were analyzed separately, systolic morning-to-morning VIM was associated with mortality (adjusted HR: 1.09, 95% -CI 1.01-1.18, p = 0.033).

CONCLUSION

In this study, day-to-day BPV was not associated with all-cause mortality in patients attending a memory clinic. However, morning-to-morning BPV was. Due to the short assessment window, there is still a lack of clarity; hence future research is warranted to clarify the role of all BPV components in aging.

Visit-to-visit variability of blood pressure and cardiovascular events among the working-age population in Japan: findings from the Japan Epidemiology Collaboration on Occupational Health Study

Increased visit-to-visit variability (VVV) of blood pressure, which is calculated based on several readings, has been suggested to be a significant predictor of cardiovascular events and mortality, independent of mean blood pressure. This study examined associations between the VVV of systolic blood pressure (SBP) measured annually and cardiovascular disease (CVD) events among 72,617 Japanese subjects. Data were obtained from the Japan Epidemiology Collaboration on Occupational Health Study, which is an ongoing epidemiological survey of workers in Japan. VVV was calculated as the coefficient of variation of SBP readings from 2008 to 2011; information on fatal and nonfatal CVD events was collected from registries of specific outcomes between April 2012 and March 2019. A Cox proportional hazards model was applied to investigate associations after adjusting for mean SBP between 2008 and 2011 and covariates. During the 7-year follow-up period, there were 63 CVD fatalities and 314 CVD events (combining fatal and nonfatal events). The results showed that a one-standard deviation increase in VVV was associated with a significant increase in the risk of CVD mortality (hazard ratio [HR] = 1.42; 95% confidence interval [CI] = 1.32-1.54); those in the highest tertile had a 3.20 times (95% CI = 1.26-8.17) higher risk of CVD mortality than those in the lowest tertile. We found less pronounced associations regarding CVD events (HR = 1.08, 95% CI = 1.02-1.15). In conclusion, VVV was significantly associated with CVD mortality in our Japanese working population.

Dose-Response Relationship Between Long-Term Blood Pressure Variability and Cognitive Decline

BACKGROUND AND PURPOSE

We aimed to test whether higher long-term blood pressure variability was associated with accelerated rate of cognitive decline and evaluate potential dose-response relationship.

METHODS

Original survey data from the Health and Retirement Study and the English Longitudinal Study of Ageing were used. Standardized Z score of cognitive function was the main outcome measure. Visit-to-visit blood pressure SD, coefficient of variation, and variation independent of mean were used. Linear mixed model and restricted spline were applied to assess association and explore dose-response pattern. Segmented regression was used to analyze dose-response relationship and estimate turning point. Meta-analysis using random-effects model was conducted to pool results, with I² used to test heterogeneity.

RESULTS

A total of 12 298 dementia-free participants were included (mean age: 64.6±8.6 years). Significant association was observed between blood pressure variability and cognitive decline. Each 10% increment in coefficient of variation of systolic and diastolic blood pressure was associated with accelerated global cognitive decline of 0.026 SD/y (95% CI, 0.016-0.036, P<0.001) and 0.022 SD/y (95% CI, 0.017-0.027, P<0.001), respectively. Nonlinear dose-response relationship was found (P<0.001 for nonlinearity), with clear turning point observed (P<0.001 for change in slopes).

CONCLUSIONS

Higher long-term blood pressure variability was associated with accelerated cognitive decline among general adults aged ≥50 years, with nonlinear dose-response relationship. Further randomized controlled trials are warranted to evaluate potential benefits of blood pressure variability-lowering strategies from a cognitive health perspective.

Ventromedial prefrontal cortex CRF1 receptors modulate the tachycardic activity of baroreflex

Ventral medial prefrontal cortex (vMPFC) glutamatergic neurotransmission has a facilitatory role on cardiac baroreflex activity which is mediated by NMDA receptors activation. Corticotrophin releasing factor receptors type1 and 2 (CRF1 and CRF2), present in the vMPFC, are colocalized in neurons containing glutamate vesicles, suggesting that such receptors may be involved in glutamate release in this cortical area. Therefore, our hypothesis is that the CRF1 and CRF2 receptors can modulate the baroreflex bradycardic and tachycardic responses. In order to prove this assumption, male Wistar rats had bilateral stainless steel guide cannula implanted into the vMPFC, and baroreflex was activated by intravenous infusion of phenylephrine or sodium nitroprusside through a vein catheter. A second catheter was implanted into the femoral artery for cardiovascular measurements. The CRF1 receptor antagonist administration in either infralimbic cortex (IL) or prelimbic cortex (PL), vMPFC regions, was unable to change the bradycardic responses but increased the slope of the baroreflex tachycardic activity. Microinjection of the CRF2 receptor antagonist into the IL and PL did not alter ether bradycardic nor tachycardic baroreflex responses. The administration of the non-selective CRF receptors agonist, urocortin in these areas, did not modify bradycardic responses but decreased tachycardia slope of the baroreflex. CRF1 receptor antagonist administration prior to non-selective CRF agonist in vMPFC prevented the tachycardic responses reduction. However, CRF2 receptor antagonism could not prevent the effect of CRF receptors agonist. These results suggest that IL and PL CRF1 but not CRF2 receptors have an inhibitory role on the baroreflex tachycardic activity. Furthermore, they have no influence on baroreflex bradycardic activity.

Slow-Paced Breathing and Autonomic Function in People Post-stroke

Purpose: To determine if acute slow breathing at 6 breaths/min would improve baroreflex sensitivity (BRS) and heart rate variability (HRV), and lower blood pressure (BP) in adults after stroke. Methods: Twelve individuals completed two randomized study visits where they performed a 15-min bout of breathing exercises at 6 breaths/min (slow) and at 12 breaths/min (control). Continuous BP and heart rate (HR) were measured throughout, and BRS, BRS response to elevations in blood pressure (BRSup), BRS response to depressions in blood pressure (BRSdown), and HRV were calculated and analyzed before (pre), during, and after (post) breathing exercises. Results: BRS increased from pre to post slow breathing by 10% (p = 0.012), whereas BRSup increased from pre to during slow breathing by 30% (p = 0.04). BRSdown increased from pre to post breathing for both breathing conditions (p < 0.05). HR (control: Δ - 4 ± 4; slow: Δ - 3 ± 4 beats/min, time, p < 0.01) and systolic BP (control: Δ - 0.5 ± 5; slow: Δ - 6.3 ± 8 mmHg, time, p < 0.01) decreased after both breathing conditions. Total power, low frequency power, and standard deviation of normal inter-beat intervals (SDNN) increased during the 6-breaths/min condition (condition × time, p < 0.001), whereas high frequency increased during both breathing conditions (time effect, p = 0.009). Conclusions: This study demonstrated that in people post-stroke, slow breathing may increase BRS, particularly BRSup, more than a typical breathing space; however, paced breathing at either a slow or typical breathing rate appears to be beneficial for acutely decreasing systolic BP and HR and increasing HRV.

The impact of acetylsalicylic acid dosed at bedtime on circadian rhythms of blood pressure in the high-risk group of cardiovascular patients-a randomized, controlled trial

Purpose

Time of drug administration may significantly influence its effect. The aim of the present study was to investigate the effect of ASA (administrated in the morning or in the evening) on the anti-hypertensive effect and diurnal blood pressure profile in the high-risk group of cardiovascular patients.

Methods

All patients (n = 114) had been diagnosed with coronary heart disease and arterial hypertension prior to the enrolment and had been treated with 75 mg per day of ASA in the morning. The patients were randomly assigned to one of the two study groups receiving 75 mg of ASA per day in a single antiplatelet therapy for 3 months in the morning (n = 58) or in the evening (n = 56). The control group (n = 61) consisted of patients with arterial hypertension but without coronary heart disease, not receiving ASA. In all the patients, during each visit, clinical blood pressure (BP) and ambulatory blood pressure measurements (ABPM) were performed.

Results

There was a significant reduction in 24-h BP and blood pressure at night in the ASA group evening group compared with the ASA morning group and the control group.

Conclusions

The present study demonstrated that compared with the use of ASA in the morning, its administration in the evening may lead to favourable drop in the ABPM and an improvement of the diurnal profile in the high-risk group of cardiovascular patients who are not naïve to ASA.

Electronic supplementary material

The online version of this article (10.1007/s00228-020-02997-8) contains supplementary material, which is available to authorized users.

Increased lipopolysaccharide-induced hypothermia in neurogenic hypertension is caused by reduced hypothalamic PGE2 production and increased heat loss

KEY POINTS

The mechanisms involved in hypothermia and fever during systemic inflammation (SI) remain largely unknown. Our data support the contention that brain-mediated mechanisms are different in hypertension during SI. Considering that, clinically, it is not easy to assess all mechanisms involved in cardiovascular and thermoregulatory control during SI, the present study sheds light on these integrated mechanisms that may be triggered simultaneously in septic hypertensive patients. The result obtained demonstrate that, in lipopolysaccharide-induced SI, an increased hypothermia is observed in neurogenic hypertension, which is caused by reduced hypothalamic prostaglandin E₂ production and increased heat loss in conscious rats. Therefore, the results of the present study provide useful insight for clinical trials evaluating the thermoregulatory outcomes of septic patients with hypertension.

ABSTRACT

Hypertension is a prevalent disease characterized by autonomic-induced elevated and sustained blood pressure levels and abnormal body core temperature (Tb) regulation. The present study aimed to determine the brain-mediated mechanisms involved in the thermoregulatory changes observed during lipopolysaccharide (LPS)-induced systemic inflammation (SI; at a septic-like model) in spontaneously hypertensive rats (SHR). We combined Tb and skin temperature (Tsk) analysis, assessment of prostaglandin (PG) E₂ levels (the proximal mediator of fever) in the anteroventral region of the hypothalamus (AVPO; an important site for Tb control), oxygen consumption analysis, cardiovascular recordings, assays of inflammatory markers, and evaluation of oxidative stress in the plasma and brain of male Wistar rats and SHR that had received LPS (1.5 mg kg^-1 ) or saline. LPS induced hypothermia followed by fever in Wistar rats, whereas, in SHR, a maintained hypothermia without fever were observed. These thermoregulatory responses were associated with an increased heat loss in SHR compared to Wistar rats. We measured LPS-induced increased PGE₂ levels in the AVPO in Wistar rats, but not in SHR. The LPS-induced drop in blood pressure was higher in SHR than in Wistar rats. Furthermore, LPS-induced plasma and brain [regions involved in autonomic control: nucleus tractus solitarius (NTS) and rostral ventrolateral medulla (RVLM)] cytokine surges were blunted, whereas oxidative stress was higher in SHR. LPS-induced SI leads to blunted cytokine surges both systemically (plasma) and centrally (NTS and RVLM) and reduced hypothalamic PGE₂ production, which are all associated with increased hypothermia mediated by increased heat loss, but not by heat production, in SHR.

Relationship between arterial stiffness and variability of home blood pressure monitoring

Variability of blood pressure (BP) is known as a prognostic value for the subsequent target organ damage in hypertensive patients. Arterial stiffness is a risk factor for cardiovascular morbidity and mortality. The relationship between the arterial stiffness and the BP variability has been controversial. The objective of the present study was to investigate the relationship between arterial stiffness and home BP variability in patients with high normal BP and new onset hypertension (HTN).Four hundred sixty three patients (252 males, 49 ± 12 year-old) with high normal BP or HTN were enrolled. Using radial applanation tonometry, pulse wave analysis (PWA) was performed for evaluation of systemic arterial stiffness. All patients underwent both home BP monitoring (HBPM) and PWA. Home BP variability was calculated as the standard deviation (SD) of 7 measurements of HBPM. Multiple linear regression analysis was performed to estimate and test the independent effects of home BP variability on the arterial stiffness.Mutivariate analysis showed that both systolic and diastolic morning BP variabilities were correlated with arterial stiffness expressed as augmentation pressure (AP, β-coefficient = 1.622, P = .01 and β-coefficient = 1.07, P = .035). The SDs of systolic and diastolic BP of evening were also associated with AP (β-coefficient = 1.843, P = .001 and β-coefficient = 1.088, P = .036). The SDs of morning and evening systolic BP were associated with augmentation index (AI, β-coefficient = 1.583, P = .02 and β-coefficient = 1.792, P = .001) and heart rate (75 bpm) adjusted AI (β-coefficient = 1.592, P = .001 and β-coefficient = 1.792, P = .001).In present study, the variability of systolic BP was closely related with arterial stiffness. The home BP variability might be important indicator of arterial stiffness.

Ambulatory Blood Pressure Response to Romantic Partner Interactions and Long-Term Cardiovascular Health Outcomes

OBJECTIVE

Lower blood pressure (BP) during romantic partner interactions may underlie the association between romantic relationships and better long-term cardiovascular health. This secondary analysis examined the effect of momentary ambulatory BP (ABP) response to partner interactions on between-person changes in left ventricular mass index and mean systolic and diastolic BP over time.

METHODS

Participants were 538 married, working adults (mean [SD] = 46.9 [8.8] years, 56.7% female) with a screening BP of ≤160/105 mm Hg. Participants completed questionnaires, 24-hour ABP monitoring, and an echocardiogram at waves 1 and 2 (mean [SD] = 6.2 [1.0] years later). Associations between ABP response to partner (versus nonpartner) interactions and cardiovascular outcomes were examined using multilevel structural equation models.

RESULTS

Participants with lower diastolic BP during partner interactions at wave 1 had a lesser increase in systolic BP at wave 2 (B = 1.68, SE = 0.61, p = .006; 9.84 mm Hg differential change in systolic BP for participants at +1/-1 SD diastolic ABP response to partner interactions). Participants with lower diastolic ABP during partner-specific interactions at wave 1 also had a lesser increase in diastolic BP (B = 0.83, SE = 0.42, p = .045; 4.89 mm Hg differential change in diastolic BP at +1/-1 SD). Systolic ABP response to partner-specific interactions did not predict changes in cardiovascular outcomes; diastolic ABP response did not predict changes in left ventricular mass index.

CONCLUSIONS

Momentary diastolic ABP response to partner-specific interactions may function as a mechanism underlying the cardioprotective effect of romantic relationships on long-term BP outcomes.

Role of dipstick proteinuria for predicting cardiovascular events: a Japanese cardiovascular hospital database analysis

Initial screening for proteinuria by urine dipstick test (UDT) may be useful for predicting clinical outcomes. The Shinken Database includes all the new patients visiting the Cardiovascular Institute Hospital in Tokyo, Japan. Patients for whom UDT was performed at their initial visit between 2004 and 2010 (n = 7131) were divided into three groups according to the test results: negative, trace, and positive (1+ to 4+) proteinuria. During the mean follow-up period of 3.4 years, 233 (3.1%) deaths, 255 (3.6%) heart failure (HF) events, and 106 (1.5%) ischemic stroke (IS) events occurred. Prevalence of atherothrombotic risks increased with an increase in the amounts of proteinuria. The incidence of all-cause death, HF and IS events increased significantly from negative to trace to positive proteinuria groups (log rank test, P for trend < 0.001). Multivariate analysis revealed independent association between proteinuria and all-cause death [hazard ratio (HR): 1.50, 95% confidence interval (CI) 1.07-2.10], HF (HR: 1.55, 95% CI 1.14-2.12), and IS (HR: 2.08, 95% CI 1.26-3.45). Even trace proteinuria was independently associated with HF (HR: 1.64, 95% CI 1.07-2.53) and IS (HR: 2.17, 95% CI 1.14-4.11) and with all-cause death (HR: 1.56, 95% CI 0.99-2.47). In conclusions, dipstick proteinuria was independently associated with cardiovascular events and death, suggesting that the UDT is a useful tool for evaluating patients' risk for such adverse events.

Orthostatic hypotension is associated with new-onset atrial fibrillation: Systemic review and meta-analysis

Introduction

Orthostatic hypotension (OH) is common among elderly patients. Its presence may herald severe underlying comorbidities and be associated with a higher risk of mortality. Interestingly, recent studies suggest that OH is associated with new-onset atrial fibrillation (AF). However, a systematic review and meta-analysis of the literature has not been performed. We assessed the association between AF and OH through a systematic review of the literature and a meta-analysis.

Methods

We comprehensively searched the databases of MEDLINE and EMBASE from inception to November 2018. Published prospective or retrospective cohort studies that compared new-onset AF between male patients with and without OH were included. Data from each study were combined using the random-effects, generic inverse-variance method of DerSimonian and Laird to calculate risk ratios and 95% confidence intervals.

Results

Four studies from October 2010 to March 2018 were included in the meta-analysis involving 76,963 subjects (of which 3318 were diagnosed with OH). The presence of OH was associated with new-onset AF (pooled risk ratio 1.48; 95% confidence interval [1.21, 1.81], p?< 0.001; I2 = 69.4%). In hypertensive patients, analysis revealed an association between OH and the occurrence of new-onset AF (OR 1.46; 95% CI [1.27, 1.68], p < 0.001 with I2 = 0).

Conclusions

OH was associated with new-onset AF up to 1.5-fold compared with those subjects without OH. The interplay between OH and AF is likely bidirectional.

Analysis of Short-term Blood Pressure Variability in Pheochromocytoma/Paraganglioma Patients

Data on short-term blood pressure variability (BPV), which is a well-established cardiovascular prognostic tool, in pheochromocytoma and paraganglioma (PPGL) patients is still lack and conflicting. We retrospectively evaluated 23 PPGL patients referred to our unit from 2010 to 2019 to analyze 24 h ambulatory blood pressure monitoring (24-h ABPM)-derived markers of short-term BPV, before and after surgical treatment. PPGL diagnosis was assessed according to guidelines and confirmed by histologic examination. The 24-h ABPM-derived markers of short-term BPV included: circadian pressure rhythm; standard deviation (SD) and weighted SD (wSD) of 24-h, daytime, and night-time systolic and diastolic blood pressure (BP); average real variability (ARV) of 24-h, daytime, and night-time systolic and diastolic BP. 7 males and 16 females of 53 ± 18 years old were evaluated. After surgical resection of PPGL we found a significant decrease in 24-h systolic BP ARV (8.8 ± 1.6 vs. 7.6 ± 1.3 mmHg, p < 0.001), in 24-h diastolic BP ARV (7.5 ± 1.6 vs. 6.9 ± 1.4 mmHg, p = 0.031), and in wSD of 24-h diastolic BP (9.7 ± 2.0 vs 8.8 ± 2.1 mmHg, p = 0.050) comparing to baseline measurements. Moreover, baseline 24-h urinary metanephrines significantly correlated with wSD of both 24-h systolic and diastolic BP. Our study highlights as PPGL patients, after proper treatment, show a significant decrease in some short-term BPV markers, which might represent a further cardiovascular risk factor.

Visit-to-visit systolic blood pressure variability in patients with ST-elevation myocardial infarction predicts long-term cardiovascular outcomes

Elevated visit-to-visit blood pressure variability (BPV), independent of mean BP, has been associated with cardiovascular events. However, its impact after ST-elevation myocardial infarction (STEMI) has not been established. This study aimed to investigate the prognostic impact of BPV on patients after STEMI. We analyzed the data and clinical outcomes of STEMI survivors who underwent successful primary coronary intervention from 2003 to 2009. BP was measured at discharge and at 1, 3, 6, 12, 24, and 36 months, and we calculated BPV as the intra-individual standard deviations (SDs) of systolic BP (SBP) across these measurements. We classified the patients as high and low-BPV group, and evaluated the outcomes: occurrence of major adverse cardiovascular events (MACEs), death, recurrent myocardial infarction, and target vessel revascularization within 60 months. We enrolled 343 patients, and mean follow-up duration was 68 ± 34 months (median: 76 months). Mean and median SBP SDs were 13.2 and 12.3 mmHg, and patients were divided into one of the two groups based on the median (high-BPV group = SD ≥ 12.3 mmHg; low-BPV group = SD < 12.3 mmHg). The MACE-free survival in the high-BPV group was significantly worse than that in low-BPV group (log-rank p = 0.035). For the high-BPV group, the risk of a MACE significantly increased by 57% (95% confidence interval: 1.03–2.39; p = 0.038). Visit-to-visit systolic BPV was associated with increased rates of adverse clinical outcomes in patients after STEMI. Careful assessment of BP and attempts to reduce BPV might be also important in STEMI survivors.

Patterns of cardiovascular variability after long-term sino-aortic denervation in unanesthetized adult rats

Baroreflex dysfunction is a diffuse chronic condition that is expected to be followed by a profound loss of organization of BP and HR variability. Nevertheless, long-term effects of baroreflex withdrawal are still debated. Aim of our work was to study BP and HR changes long term after sino-aortic denervation (SAD). Inter-beat-interval (IBI) and intra-arterial BP were recorded beat-by-beat in 43 Wistar-Kyoto rats (Controls, n = 33; SAD rats, n = 10). Power spectra were calculated in controls and in SAD rats within three days and at seven months from denervation. Compared to controls, chronic SAD rats showed 1) similar mean BP (control vs SAD: 95 ± 16 vs 87 ± 22 mmHg) and IBI (171 ± 22 vs 181 ± 15 ms) values, 2) dramatically higher values of BP variance (12 ± 2 vs 64 ± 2 mmHg2, p < 0.01) and of ultra- (ULF) and very-low-frequency (VLF) BP oscillations, 3) dramatically higher values of IBI variability (24 ± 2 vs 71 ± 4 ms2, p < 0.01) and of ULF-IBI oscillations that were synchronized with BP oscillations. Chronic SAD rats reveal a marked change in the pattern of cardiovascular variability characterized by the appearance of synchronized slower oscillations of BP and HR. The cardiovascular system, therefore, retains a high level of organization despite the absence of a reflex control mechanism.

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

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

Effect of vitamin D on the variability of blood pressure in premenopausal and menopausal hypertensive women in the area of Blida (Algeria)

OBJECTIVE

To evaluate the effect of 25 (OH) vitamin D supplementation on blood pressure (BP) variability in hypertensive women in the pre-menopausal and post-menopausal periods.

MATERIALS AND METHODS

881 hypertensive women prospectively followed for an interventional study between January 2016 and September 2017, in specialized consultation at the department of internal medicine at the Blida University Hospital (Algeria). Four hundred and thiry nine premenopausal women (group I) and 442 menopausal women (group II). The initial serum 25 (OH) D level for each group was determined by the enzyme immunoassay. In groups I and II, we identified 2 subgroups, A: insufficiency (vit D between 29 and 20ng/ml) and B: deficiency (vit D less than 20ng/L). Antihypertensive therapy was supplemented with an additional 200000IU/month cholecalciferol for the two B subgroups. The variability in BP was calculated as the ratio of mean systolic and diastolic BP during daytime and nighttime, with performing ambulatory BP measurement at baseline, 3, 6, and 12 months of follow-up.

RESULTS

At inclusion, the level of 25 (OH) D was lower (P<0.05) in subgroups IB (19.3±8.5ng/ml) and IIB (18.2±9, 5ng/ml) compared to subgroups IA (28.1±10.7ng/ml) and IIA (25.2±10.1ng/ml). After supplementation, the level of 25 (OH) D increased in subgroup IB (38.3±11.9ng/ml) and in subgroup IIB (37.3±10, 5ng/ml) and became higher (P<0.001) than in subgroups IA and IIA. Between subgroups IA and IB, at inclusion, there is no difference (P>0.05) in the SBP and DBP variability during the day and at night. After treatment, the variability of the SBP at night became lower (P<0.02) in group IB compared to group IA. In subgroup IIB, daytime variability indices were higher (P=0.04) at inclusion than in group IIA. After treatment, the variability of SBP during the day decreased but remained the highest (P<0.05) in subgroup IIB (14.8±10.8mmHg) compared to subgroup IB (12.0±8.1mmHg), as well as to subgroups IIA (10.9±9.8mmHg) and IA (10±8.1mmHg). We found a significant correlation of cholecalciferol with the variability of SBP during the day.

CONCLUSIONS

Vitamin D deficiency appears to be a factor of BP variability. Although the variability of the postmenopausal group remains higher than that of the other groups, the correction of the level of 25 (OH) D by the supply of cholecalciferol 200000 IU per month leads to a reduction in the variability of BP in the studied hypertensive women could help to prevent morbimortal complications.

Visit-to-visit HbA1c variability and systolic blood pressure (SBP) variability are significantly and additively associated with mortality in individuals with type 1 diabetes: An observational study

AIM

To investigate the relationship between variability in both visit-to-visit HbA1c and SBP and mortality in individuals with type 1 diabetes.

METHODS

The Scottish Care Information (SCI) Diabetes dataset was used to identify 5952 individuals with type 1 diabetes for inclusion in this observational study. The SCI-Diabetes dataset allowed access to blood pressure values, HbA1c readings, demographic information and mortality rates for all study participants. Participants were dichotomized to above and below median values for both HbA1c coefficient of variation (CV) and SBP CV, thus dividing participants into 4 cohorts for survival analysis. Survival analysis was carried out over 1430 days. A Cox proportional hazard model was used to allow comparison of mortality between the 4 cohorts.

RESULTS

Of the 5952 patients, death occurred in 416. CV for both HbA1c and SBP were significantly associated with mortality. The median values for HbA1c CV and SBP CV were 8.0 and 8.1, respectively. The hazard ratio for high HbA1c CV only (P = .0015) was 1.78 ± 0.36. The hazard ratio for high SBP CV only (P = .0018) was 1.69 ± 0.33. The hazard ratio for both high HbA1c CV and high SBP CV (P < .00001) was 2.37 ± 0.32.

CONCLUSIONS

Our findings demonstrate that variability of both HbA1c and SBP is significantly and additively associated with mortality in individuals with type 1 diabetes. The variability of these parameters might be useful for risk stratification and is a potential target for future interventional studies.

Age modifies the relation between intraindividual measurement-to-measurement variation in blood pressure and cognitive function: the Maine-Syracuse Study

BACKGROUND

There is evidence to suggest that intraindividual variability in blood pressure (BP IIV) may be superior to mean BP for predicting cognitive function, taken from both within a single visit and between-visits. BP IIV increases with age in studies of persons middle-aged and older. The aim was therefore to investigate age by BP IIV (SBP and DBP) interactions with regard to cognitive functioning while considering medication class and polypharmacy, which may also affect BP IIV with advancing age.

METHOD AND RESULTS

Cross-sectional analyses were performed on 980 community-dwelling individuals from the Maine-Syracuse Longitudinal Study. Automated BP measures were taken 15 times (five times each in sitting, reclining, and standing positions). Cognitive function was assessed using a thorough neuropsychological test battery following the BP assessment. A significant age by BP IIV interaction was observed. For individuals aged over age 60 years, IIV in SBP and DBP was inversely associated with Global Composite, Scanning and Tracking, and the Similarities test. IIV in SBP was additionally associated with Verbal Memory and the Mini-Mental State Examination. DBP IIV was additionally related to the Visual-Spatial Memory and Organization composite. There were no significant associations between BP IIV and cognitive function in those aged less than 60 years.

CONCLUSION

BP IIV is an important predictor of cognition with advancing age.

Visit-to-Visit Blood Pressure Variability and Mortality and Cardiovascular Outcomes Among Older Adults: The Health, Aging, and Body Composition Study

BACKGROUND

Level of blood pressure (BP) is strongly associated with cardiovascular (CV) events and mortality. However, it is questionable whether mean BP can fully capture BP-related vascular risk. Increasing attention has been given to the value of visit-to-visit BP variability.

METHODS

We examined the association of visit-to-visit BP variability with mortality, incident myocardial infarction (MI), and incident stroke among 1,877 well-functioning elders in the Health, Aging, and Body Composition Study. We defined visit-to-visit diastolic BP (DBP) and systolic BP (SBP) variability as the root-mean-square error of person-specific linear regression of BP as a function of time. Alternatively, we counted the number of considerable BP increases and decreases (separately; 10mm Hg for DBP and 20mm Hg for SBP) between consecutive visits for each individual.

RESULTS

Over an average follow-up of 8.5 years, 623 deaths (207 from CV disease), 153 MIs, and 156 strokes occurred. The median visit-to-visit DBP and SBP variability was 4.96 mmHg and 8.53 mmHg, respectively. After multivariable adjustment, visit-to-visit DBP variability was related to higher all-cause (hazard ratio (HR) = 1.18 per 1 SD, 95% confidence interval (CI) = 1.01-1.37) and CV mortality (HR = 1.35, 95% CI = 1.05-1.73). Additionally, individuals having more considerable decreases of DBP (≥10mm Hg between 2 consecutive visits) had higher risk of all-cause (HR = 1.13, 95% CI = 0.99-1.28) and CV mortality (HR = 1.30, 95% CI = 1.05-1.61); considerable increases of SBP (≥20mm Hg) were associated with higher risk of all-cause (HR = 1.18, 95% CI = 1.03-1.36) and CV mortality (HR = 1.37, 95% CI = 1.08-1.74).

CONCLUSIONS

Visit-to-visit DBP variability and considerable changes in DBP and SBP were risk factors for mortality in the elderly.

Static magnetic field reduces blood pressure short-term variability and enhances baro-receptor reflex sensitivity in spontaneously hypertensive rats

PURPOSE

It has been shown that chronic exposure of young spontaneously hypertensive rats (SHR) to static magnetic field (SMF) delays the development of overt hypertension. Therefore the aim of the present work was to investigate the effects of SMF on autonomic cardiovascular control in adult spontaneously hypertensive rats.

MATERIALS AND METHODS

Experiments were performed in freely moving spontaneously hypertensive rats equipped with femoral arterial catheter for blood pressure recording. Spontaneously hypertensive rats were exposed for 30 days to upward-oriented SMF (n = 17) or downward-oriented SMF (n = 17) of 16 mT intensity. A control group of spontaneously hypertensive rats (n = 17) was not exposed to SMF. Neurogenic cardiovascular control was evaluated by spectral analysis of arterial blood pressure and heart rate short-term variability and baro-receptor reflex sensitivity using the sequence method.

RESULTS

Exposure of spontaneously hypertensive rats to both upward- and downward-oriented SMF significantly reduced arterial blood pressure and enhanced baro-receptor reflex sensitivity. Downward-oriented SMF reduced heart rate, too. SMF of either orientation reduced systolic blood pressure variability in very low frequency domain while downward-oriented SMF also reduced low-frequency and increased high frequency domains.

CONCLUSION

It follows that prolonged exposure to SMF is beneficial for neurogenic cardiovascular control in hypertension.

Baroreflex Sensitivity in Children and Adolescents: Physiology, Hypertension, Obesity, Diabetes Mellitus

The increased prevalence of obesity in children and its complications have led to a greater interest in studying baroreflex sensitivity (BRS) in children. This review of BRS in children and adolescents includes subtopics on: 1. Resting values of BRS and their reproducibility, 2. Genetics of BRS, 3. The role of a primarily low BRS and obesity in the development of hypertension, and 4. Association of diabetes mellitus, BRS, and obesity. The conclusions specific to this age follow from this review: 1. The mean heart rate (HR) influences the measurement of BRS. Since the mean HR decreases during adolescence, HR should be taken into account. 2. A genetic dependency of BRS was found. 3. Low BRS values may precede pathological blood-pressure elevation in children with white-coat hypertension. We hypothesize that low BRS plays an active role in the emergence of hypertension in youth. A contribution of obesity to the development of hypertension was also found. We hypothesize that both factors, a primarily low BRS and obesity, are partially independent risk factors for hypertension in youths. 4. In diabetics, a low BRS compared to healthy children can be associated with insulin resistance. A reversibility of the BRS values could be possible after weight loss.

Characteristic enhancement of blood pressure V-shaped waves in sinoaortic-denervated rats in a conscious and quiet state

A hemodynamic feature of chronic sinoaortic-denervated (SAD) rats is the increase in blood pressure variability (BPV) without significant changes in the average level of blood pressure (BP). The current study was designed to investigate the changes in BP V-shaped waves (V waves) in SAD rats. Sprague-Dawley (SD) rats were divided into 2 groups: SAD rats and sham-operated rats (n=13). Hemodynamics measurements were obtained in conscious, freely moving rats, four weeks after sinoaortic denervation or sham operation. V wave indices were evaluated in rats in both conscious and quiet states. Additionally, normal and high BPV was simulated by the production of V waves with different amplitudes. The results showed that the V wave amplitude was dramatically increased, with a significantly prolonged duration and reduced frequency in SAD rats. V wave BPV in SAD rats was significantly increased, though BP remained unchanged. The twenty-four hour BPV in all rats was positively correlated with amplitude, duration time and V wave BPV and negatively correlated with frequency. The systolic BP spectral powers in the low frequency range (0.38-0.45 Hz) were significantly reduced in the V waves of SAD rats. Moreover, there was a remarkable increase in mean BPV and a normal mean BP after simulating high BPV in SAD rats. These results suggest that enhancement of V waves might be a waveform character of BP in SAD rats in both the conscious and quiet states. These types of V waves appear to be related to a depression of sympathetic regulation of BP induced by sinoaortic denervation.

Increased Blood Pressure Variability Prior to Chronic Kidney Disease Exacerbates Renal Dysfunction in Rats

Increased blood pressure variability (BPV), which can be experimentally induced by sinoaortic denervation (SAD), has emerged as a new marker of the prognosis of cardiovascular and renal outcomes. Considering that increased BPV can lead to organ-damage, the goal of the present study was to evaluate the effects of SAD on renal function in an experimental model of chronic kidney disease (CKD). SAD was performed in male Wistar rats 2 weeks before 5/6 nephrectomy and the animals were evaluated 4 weeks after the induction of CKD. Our data demonstrated that BPV was increased in SAD and CKD animals and that the combination of both conditions (SAD+CKD) exacerbated BPV. The baroreflex sensitivity index was diminished in the SAD and CKD groups; this reduction was more pronounced when SAD and CKD were performed together. 5/6 nephrectomy led to hypertension, which was higher in SAD+CKD animals. Regarding renal function, the combination of SAD and CKD resulted in reduced renal plasma and blood flow, increased renal vascular resistance and augmented uraemia when compared to CKD animals. Glomerular filtration rate and BPV were negatively correlated in SAD, CKD, and SAD+CKD animals. Moreover, SAD+CKD animals presented a higher level of glomerulosclerosis when compared to all other groups. Cardiac and renal hypertrophy, as well as oxidative stress, was also further increased when SAD and CKD were combined. These results show that SAD prior to 5/6 nephrectomy exacerbates renal dysfunction, suggesting that previous augmented BPV should be considered as an important factor to the progression of renal diseases.

The volume of the carotid bodies and blood pressure variability and pulse pressure in patients with essential hypertension

AIM

To assess the relationship between the volume of the carotid bodies (VrCB+lCB) examined by means of computed tomography angiography (CTA) and blood pressure variability and pulse pressure (PP) in 24-hour ambulatory blood pressure monitoring (ABPM) in patients with essential hypertension.

MATERIALS AND METHODS

A group of 52 patients with essential hypertension was examined (mean age: 68.32±12.31 years), the sizes of carotid bodies were measured by means of carotid artery CTA, and 24-hour ABPM was carried out. The 24-hour ABPM established systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), PP, SBP variability (SBPV), and DBP variability (DBPV).

RESULTS

SBP, MAP, and SBPV were significantly higher in the group of hypertension patients with VrCB+lCB equal to or above the median than in the group of hypertension patients with VrCB+lCB less than the median, as well as in the group of hypertension patients with oversized carotid bodies, than in the group of hypertension patients with normal VrCB+lCB. Moreover, the PP was statistically significantly higher in the group of hypertension patients with VrCB+lCB equal to or above the median than in the group of hypertension patients with VrCB+lCB less than the median. The existence of statistically significant positive linear relationships was revealed between VrCB+lCB and SBP, PP, and SBPV. A higher body mass index, older age, smoking, and higher VrCB+lCB are independent risk factors increasing SBPV in the research group.

CONCLUSION

A positive relationship between the size of the carotid bodies and variability of the SBP and PP is observed in patients with essential hypertension.

Blood pressure variability: assessment, predictive value, and potential as a therapeutic target

A large body of evidence has consistently supported the relationship between blood pressure (BP) levels and the risk of cardiovascular complications. In recent years, several independent studies have also indicated that this risk may not only depend on the magnitude of the blood pressure elevation per se but also on the presence of other associated conditions such as increased blood pressure variability. This concept has been supported by a series of reports, most of which post hoc analyses of clinical trials in hypertension, showing that increasing values of BP variability (BPV) (either in the short term, in the midterm, or in the long term) may predict development, progression, and severity of cardiac, vascular, and renal organ damage, as well as cardiovascular events and mortality. Remarkably, studies conducted in populations at high cardiovascular risk have shown increasing values of BPV in the individual subjects (so-called intra- or within-individual BPV) to be strong predictors of cardiovascular morbidity and mortality, even to a larger extent than average BP values. However, in subjects at low to moderate cardiovascular risk, the contribution of BPV to cardiovascular risk prediction over and beyond average BP values has been shown to be only moderate. The aim of this paper is to critically review the evidence addressing the prognostic relevance of different components of BPV addressing a yet open question, i.e., whether routine assessment of BPV in clinical practice should be regarded as an additional target of antihypertensive treatment to improve cardiovascular protection.

Effects of calcium channel blocker-based combinations on intra-individual blood pressure variability: post hoc analysis of the COPE trial

Visit-to-visit blood pressure (BP) variability is an important predictor of stroke. However, which antihypertensive drug combination is better at reducing visit-to-visit BP variability and therefore at reducing stroke incidence remains uncertain. We have previously reported that the dihydropyridine calcium channel blocker benidipine combined with a β-blocker appeared to be less beneficial in reducing the risk of stroke than a combination of benidipine and thiazide. Here, we further compare the visit-to-visit BP variability among three benidipine-based regimens, namely angiotensin receptor blocker (ARB), β-blocker and thiazide combinations. The present post hoc analysis included 2983 patients without cardiovascular events or death during the first 18 months after randomization. We compared the BP variability (defined as the s.d. and the coefficient of variation (CV)), maximum systolic BP (SBP) and diastolic BP (DBP) of the clinic mean on-treatment BPs obtained at 6-month intervals, starting 6 months after the treatment initiation, among the 3 treatments (ARB, n=1026; β-blocker, n=966; thiazide, n=991). During the first 6–36 months after randomization, both the s.d. and CV-BPs were lower in the benidipine–thiazide group than in the benidipine–β-blocker group (s.d.-SBP, P=0.019; s.d.-DBP, P=0.030; CV-SBP, P=0.012; CV-DBP, P=0.022). The s.d. and CV in the ARB group did not reach statistical significance compared with the other two groups. The maximum BPs did not differ among the three treatments. These findings suggest that the benidipine–thiazide combination may reduce visit-to-visit BP variability more than the benidipine–β-blocker combination.

Should the sympathetic nervous system be a target to improve cardiometabolic risk in obesity?

The sympathetic nervous system (SNS) plays a key role in both cardiovascular and metabolic regulation; hence, disturbances in SNS regulation are likely to impact on both cardiovascular and metabolic health. With excess adiposity, in particular when visceral fat accumulation is present, sympathetic activation commonly occurs. Experimental investigations have shown that adipose tissue releases a large number of adipokines, cytokines, and bioactive mediators capable of stimulating the SNS. Activation of the SNS and its interaction with adipose tissue may lead to the development of hypertension and end-organ damage including vascular, cardiac, and renal impairment and in addition lead to metabolic abnormalities, especially insulin resistance. Lifestyle changes such as weight loss and exercise programs considerably improve the cardiovascular and metabolic profile of subjects with obesity and decrease their cardiovascular risk, but unfortunately weight loss is often difficult to achieve and sustain. Pharmacological and device-based approaches to directly or indirectly target the activation of the SNS may offer some benefit in reducing the cardiometabolic consequences of obesity. Preliminary evidence is encouraging, but more trials are needed to investigate whether sympathetic inhibition could be used in obesity to reverse or prevent cardiometabolic disease development. The purpose of this review article is to highlight the current knowledge of the role that SNS plays in obesity and its associated metabolic disorders and to review the potential benefits of sympathoinhibition on metabolic and cardiovascular functions.

Measurement of blood pressure variability and the clinical value

Authors have collected and analyzed literature data on blood pressure variability. They present the methods of blood pressure variability measurement, clinical value and relationships with target organ damages and risk of presence of cardiovascular events. They collect data about the prognostic value of blood pressure variability and the effects of different antihypertensive drugs on blood pressure variability. They underline that in addition to reduction of blood pressure to target value, it is essential to influence blood pressure fluctuation and decrease blood pressure variability, because blood pressure fluctuation presents a major threat for the hypertensive subjects. Data from national studies are also presented. They welcome that measurement of blood pressure variability has been included in international guidelines. Orv. Hetil., 2014, 155(42), 1661–1672.

Melatonin secretion is impaired in women with preeclampsia and an abnormal circadian blood pressure rhythm

Non-dipping circadian blood pressure (BP) is a common finding in preeclampsia, accompanied by adverse outcomes. Melatonin plays pivotal role in biological circadian rhythms. This study investigated the relationship between melatonin secretion and circadian BP rhythm in preeclampsia. Cases were women with preeclampsia treated between January 2006 and June 2007 in the University Hospital of Larissa. Volunteers with normal pregnancy, matched for chronological and gestational age, served as controls. Twenty-four hour ambulatory BP monitoring was applied. Serum melatonin and urine 6-sulfatoxymelatonin levels were determined in day and night time samples by enzyme-linked immunoassays. Measurements were repeated 2 months after delivery. Thirty-one women with preeclampsia and 20 controls were included. Twenty-one of the 31 women with preeclampsia were non-dippers. Compared to normal pregnancy, in preeclampsia there were significantly lower night time melatonin (48.4 ± 24.7 vs. 85.4 ± 26.9 pg/mL, p<0.001) levels. Adjustment for circadian BP rhythm status ascribed this finding exclusively to non-dippers (p<0.01). Two months after delivery, in 11 of the 21 non-dippers both circadian BP and melatonin secretion rhythm reappeared. In contrast, in cases with retained non-dipping status (n=10) melatonin secretion rhythm remained impaired: daytime versus night time melatonin (33.5 ± 13.0 vs. 28.0 ± 13.8 pg/mL, p=0.386). Urinary 6-sulfatoxymelatonin levels were, overall, similar to serum melatonin. Circadian BP and melatonin secretion rhythm follow parallel course in preeclampsia, both during pregnancy and, at least 2 months after delivery. Our findings may be not sufficient to implicate a putative therapeutic effect of melatonin, however, they clearly emphasize that its involvement in the pathogenesis of a non-dipping BP in preeclampsia needs intensive further investigation.

Development of attenuated baroreflexes in obese Zucker rats coincides with impaired activation of nucleus tractus solitarius

Adult obese Zucker rats (OZR; >12 wk) develop elevated sympathetic nerve activity (SNA) and mean arterial pressure (MAP) with impaired baroreflexes compared with adult lean Zucker rats (LZR) and juvenile OZR (6-7 wk). In adult OZR, baroreceptor afferent nerves respond normally to changes in MAP, whereas electrical stimulation of baroreceptor afferent fibers produces smaller reductions in SNA and MAP compared with LZR. We hypothesized that impaired baroreflexes in OZR are linked to reduced activation of brain stem sites that mediate baroreflexes. In conscious adult rats, a hydralazine (HDZ)-induced reduction in MAP evoked tachycardia that was initially blunted in OZR, but equivalent to LZR within 5 min. In agreement, HDZ-induced expression of c-Fos in the rostral ventrolateral medulla (RVLM) was comparable between groups. In contrast, phenylephrine (PE)-induced rise in MAP evoked markedly attenuated bradycardia with dramatically reduced c-Fos expression in the nucleus tractus solitarius (NTS) of adult OZR compared with LZR. However, in juvenile rats, PE-induced hypertension evoked comparable bradycardia in OZR and LZR with similar or augmented c-Fos expression in NTS of the OZR. In urethane-anesthetized rats, microinjections of glutamate into NTS evoked equivalent decreases in SNA, heart rate (HR), and MAP in juvenile OZR and LZR, but attenuated decreases in SNA and MAP in adult OZR. In contrast, microinjections of glutamate into the caudal ventrolateral medulla, a target of barosensitive NTS neurons, evoked comparable decreases in SNA, HR, and MAP in adult OZR and LZR. These data suggest that OZR develop impaired glutamatergic activation of the NTS, which likely contributes to attenuated baroreflexes in adult OZR.

Association of ambulatory blood pressure and heart rate with advanced white matter lesions in ischemic stroke patients

BACKGROUND

White matter lesions (WMLs) are a common finding in stroke patients, and the most important risk factors are old age and hypertension. Although many studies have described the association between WMLs and ambulatory blood pressure monitoring (ABPM) parameters in healthy subjects and hypertensive patients, little is known about the association in hypertensive ischemic stroke patients.

METHODS

From July 2009 to June 2012, 169 consecutive hypertensive noncardioembolic ischemic stroke patients were recruited within 1 week of suffering a stroke, and ABPM was applied 1 or 2 weeks after stroke onset. The subjects were classified into 2 groups according to the presence of advanced WMLs, and their ABPM parameters were compared. Finally, multivariable logistic regression analyses were performed to investigate the independent relationships between WMLs and ABPM parameters.

RESULTS

Seventy (41%) patients had advanced WMLs. In univariable analysis, higher 24-hour, awake, and asleep systolic blood pressure (SBP)/diastolic blood pressure levels and 24-hour pulse pressure were associated with advanced WMLs. However, circadian blood pressure parameters such as 24-hour BP variability, morning surge, and nocturnal dipping pattern were not associated with advanced WMLs. After adjustments, old age (odds ratio (OR) = 1.063; 95% confidence interval (CI) = 1.024-1.104; P = 0.002), high 24-hour SBP levels (OR = 1.055; 95% CI = 1.028-1.082; P < 0.001), and high 24-hour heart rate (OR = 1.041; 95% CI = 1.006-1.078; P = 0.023) were independently associated with advanced WMLs.

CONCLUSIONS

In addition to old age and elevated 24-hour SBP, increased heart rate is associated with advanced WMLs in ischemic stroke patients. Heart rate deserves more attention in predicting advanced WMLs in those patients.