Decrease In Blood Pressure Variability Research Articles

Abstract P329: Mycophenolate Mofetil Enhances Short-Term Blood Pressure Variability During Recovery in Salt-Sensitive Hypertensive African Americans

Elevated blood pressure variability (BPV) is an independent risk factor for cardiovascular disease (CVD), kidney disease, dementia, and stroke. High BPV is thought to be caused by arterial stiffness, vascular remodeling, inflammatory cascades, and neurohormonal mechanisms. This study aims to investigate the potential impact of mycophenolate mofetil (MMF) on short-term BPV in the context of salt-sensitive hypertension among African Americans (AA). MMF’s anti-inflammatory properties hold promise as a potential intervention for hypertension management by modulating short-term BPV. AA participants,18-50 years, normotensive, not pregnant, and not on prescription medications were recruited. In this crossover study, 51 participants received either MMF or a placebo daily. Physiological parameters were monitored every 15 minutes during a 3-hour psychosocial stressor assessment with rest, stress, and recovery periods. BPV was assessed using coefficient of variation (CV), standard deviation (SD), and average real variability (ARV). The treatment group showed a significant decrease in SBP CV (p < 0.05) during stress. During recovery, SBP SD (p, 0.05) and SBP ARV (p < 0.05) significantly increased in individuals receiving MMF treatment. Age-stratified analysis maintained significant effects of MMF on BPV during stress. Gender did not significantly alter the observed effects of MMF on BPV. Our study highlights the effectiveness of MMF in reducing BPV during acute stress, potentially lowering adverse cardiovascular events. MMF-treated groups showed increased BPV during recovery, indicating a quicker BP recovery to baseline. While a decrease in BPV during the stress period was observed, it was supported only by CV. The significant increase in BPV in the treatment group during recovery indicates MMF's ability to expedite the inflammatory stress response. The observed decrease in BPV during stress suggests a swifter return to baseline BP, potentially offering benefits for non-stress baseline physiology. Further research is warranted to clarify the mechanisms and clinical significance of these findings, impacting hypertension assessment and management. MMF treatment induces distinct changes in BPV during recovery, suggesting that MMF may positively influence BP regulation through a variety of inflammatory pathways. The alterations in SBP BPV underscore MMF's therapeutic potential for managing BPV and reducing cardiovascular risk in salt-sensitive, hypertensive AAs.

Age differences in the impact of dietary salt on metabolism, blood pressure and cognitive function in male rats.

The influence of salt consumption on physiological processes, especially blood pressure (BP), metabolism, and cognition, remains a topical concern. While guidelines endorse reduced salt diets, there are gaps in understanding the age-specific implications and challenges in adherence. The present study delved into the differential effects of salt intake on young adult and aged male rats over a 12-week period, using control, low-, and high-salt diets. Key metrics, such as BP, cognition, and general parameters, were monitored. Our findings revealed significant age-dependent effects of salt intake on survival rates, body weight, blood sodium, blood glucose, blood lipids, BP, heart rates, and cognition. Notably, young adult rats did not show significant sodium level changes on a high-salt diet, whereas aged rats experienced increased sodium levels even on a normal salt diet. Blood glucose levels decreased significantly in aged rats on a high-salt diet but remained stable in young adults. Aged rats had the highest survival rates on low-salt diets. Low-salt diets led to reduced BP in both age groups, more significantly in young adults. Young adult rats displayed increased BP variability on both high- and low-salt diets, while a decrease in BP variability was exclusive to aged rats on a low-salt diet. There were significant differences across age groups in short-term memory, but not in long-term memory. The study provides a nuanced understanding of the age-dependent physiological effects of salt intake, suggesting the necessity of age-specific guidelines for public health.

Effects of olmesartan and amlodipine on blood pressure, endothelial function, and vascular inflammation

BackgroundAnti-hypertensive drugs can improve vascular endothelial function. However, the mechanism remains to be elucidated. ObjectivesThis study sought to investigate mechanisms of anti-hypertensive drugs on improvement of vascular endothelial function in patients with essential hypertension. MethodsForty-five patients (mean age 58.5 ± 11.2 years) with uncontrolled essential hypertension were randomly assigned to receive olmesartan, an angiotensin II type 1 receptor blocker (ARB) (N = 23), or amlodipine, a calcium channel blocker (CCB) (N = 22), for 6 months. Endothelial function was evaluated by flow-mediated dilatation (FMD) of the brachial artery. Vascular inflammation was measured by blood-normalized standardized uptake value, known as a target-to-background ratio (TBR) within the carotid arteries using 18F-fluorodeoxyglucose-positron emission tomography combined with computed tomography. ResultsThere were no significant differences of baseline clinical data between the ARB and CCB groups. Both anti-hypertensive drugs comparably lowered blood pressure and increased %FMD. TBR values were reduced by olmesartan (P < .001), while blood pressure variability was decreased by amlodipine (P = .004). Changes in %FMD from baseline (Δ%FMD) were inversely associated with ΔTBR in the olmesartan group (r = − .606, P = .003) and with Δsystolic blood pressure variability in the amlodipine group (r = − .434, P = .039). ConclusionOur study indicated that olmesartan and amlodipine could improve endothelial function in patients with essential hypertension in different manners, suppression of vascular inflammation, and decrease in blood pressure variability, respectively.

Glyceryl trinitrate-induced blood pressure variability decrease during head-up tilt test predicts vasovagal response.

Glyceryl trinitrate (GTN) provoked cardioinhibitory syncope during the head-up tilt test is preceded by a period of disrupted blood pressure variability (BPV). Endogenous nitric oxide (NO) attenuates BPV independently of blood pressure (BP). We hypothesized that exogenous NO donor GTN might decrease BPV during the presyncope period. A decrease in BPV may predict the tilt outcome. We analyzed 29 tilt test recordings of subjects with GTN-induced cardioinhibitory syncope and 30 recordings of negative subjects. A recursive autoregressive model of BPV after GTN was performed; powers of the respiratory (0.15-0.45 Hz) and nonrespiratory frequency (0.01-0.15 Hz) bands were calculated for each of the 20 normalized time periods. The post-GTN relative changes in heart rate, BP, and BPV were calculated. In the syncope group, spectral power of nonrespiratory frequency systolic and diastolic BPV progressively felt for 30% after GTN application and stabilized after 180 s. BP started to fall 240 s after the GTN application. Decrease in nonrespiratory frequency power of diastolic BPV 20 s after GTN administration predicted cardioinhibitory syncope (area under the curve 0.811; 77% sensitivity; 70% specificity; cutoff value > 7%). GTN application during the tilt test attenuates systolic and diastolic nonrespiratory frequency BPV during the presyncope period, independent of BP. A decrease in nonrespiratory frequency diastolic BPV 20 s after GTN application predicts cardioinhibitory syncope with good sensitivity and moderate specificity.

CHRONOBIOLOGICAL ASPECTS OF ARTERIAL PRESSURE LEVEL IN SCHOOLCHILDREN WITH ARTERIAL PREHYPERTENSION

Introduction. Arterial pressure has significant diurnal fluctuations, reaching its minimum and maximum values at certain hours of the day. For a complete characterization of arterial hypertension in recent years, the method of daily monitoring of arterial pressure is most often used, which makes it possible to determine the forms of the disease (labile and stable), circadian rhythms of arterial pressure and its variability. The use of this method in children may be even more important than in adults.Aim: to evaluate the chronobiological aspects of the level of arterial pressure in schoolchildren with arterial prehypertension.Materials and methods. 54 school-age children were examined, who were divided into the following groups: the main group consisted of 24 children with arterial prehypertension (high blood pressure) and the control group - 30 children with normal blood pressure.Chronobiological aspects of the level of arterial pressure in schoolchildren were assessed using daily monitoring of arterial pressure. The 24-hour blood pressure device provided long-term recording of blood pressure fluctuations during normal 24-hour activity and during patient’s sleep.Statistical processing of the obtained data was carried out using Microsoft Office Excel and Statistica 10.0 applications. Research results. When evaluating the characteristics of time indices of blood pressure in the examined children, it was found that children with prehypertension most often had an increase in systolic blood pressure at night.Comparing the features of daily blood pressure fluctuations between children with prehypertension and children from the control group, certain differences were identified that were observed in the curves of systolic blood pressure and diastolic blood pressure, especially at night.When assessing the variability of the average daily and average night levels of systolic and diastolic blood pressure in children by groups, it was found that the variability of systolic and diastolic blood pressure in children with prehypertension was probably lower than in children from the control group.Additionally, the features of the daily fluctuations in mean arterial pressure were evaluated, because it simultaneously takes into account the daily fluctuations of both systolic and diastolic blood pressure. The T-test showed that the mean arterial pressure level was probably higher in children with prehypertension (p&lt;0,05) compared to children from the control group.Conclusions.1. There is a phenomenon of a decrease in blood pressure variability in children with prehypertension (especially at night), which can be regarded as a risk factor for the development of arterial hypertension.2. Based on the presence of a probable difference in the indicators of daily fluctuations in mean arterial pressure among children from the control group and children with prehypertension, the latter have an increase in the dynamic load on the vascular wall, which can lead to a slowdown in the blood flow velocity in the capillary bed and also act as a predictor of arterial hypertension.

Ambulatory Blood Pressure Variability after Adenotonsillectomy in Childhood Sleep Apnea.

To investigate the influence of adenotonsillectomy (T&A) on ambulatory blood pressure (BP) variability in children with obstructive sleep apnea (OSA). Prospective, interventional study. Children with OSA symptoms were recruited from a tertiary center. After OSA diagnosis was confirmed (ie, apnea-hypopnea index [AHI] > 1), these children underwent T&A for treatment. We performed polysomnography and 24-hour recordings of ambulatory BP before and 3 to 6 months postoperatively. Ambulatory BP variability was presented as the standard deviation of mean blood pressure in the 24-hour monitoring of ambulatory BP. Differences in BP variability among different subgroups were tested using a multivariable linear mixed model. A total of 190 children were enrolled (mean age: 7.8 ± 3.3 years; 73% were boys; 34% were obese). The AHI significantly decreased from 12.3 ± 17.0 to 2.7 ± 5.5 events/hr after T&A. Overall, daytime, and nighttime ambulatory BP did not significantly change postoperatively, and overall, daytime, and nighttime ambulatory BP variability did not differ significantly preoperatively and postoperatively. In the subgroup analysis, children aged <6 years demonstrated a significantly greater decrease in ambulatory BP variability postoperatively than those aged >6 years (nighttime diastolic BP variability: 9.9 to 7.7 vs. 8.9 to 9.4). Children with hypertension also showed a significantly greater decrease in ambulatory BP variability than those without hypertension. We concluded that overall ambulatory BP variability does not significantly change after T&A in children with OSA. Moreover, young-aged and hypertensive children demonstrate a significant decrease in BP variability after T&A. 4 Laryngoscope, 132:2491-2497, 2022.

Blood pressure variability in children with obesity and sleep-disordered breathing following positive airway pressure treatment.

Obese youth with sleep-disordered breathing are treated with positive airway pressure to improve sleep and cardiovascular status. While improvements in sleep parameters have been confirmed, a study by Katz et al. showed no major improvement in ambulatory blood pressure. The aim of this ancillary study was to analyze short-term blood pressure variability, following positive airway pressure treatment, as a more sensitive marker of cardiovascular health. We analyzed 24-h blood pressure variability data in 17 children, taken at baseline and after 12 months of treatment. These data were derived from an already published prospective, multicenter cohort study conducted in 27 youth (8-16 years) with obesity who were prescribed 1-year of positive airway pressure for moderate-severe sleep-disordered breathing. Significant decreases were found in 24 h systolic blood pressure (p = 0.040) and nighttime diastolic blood pressure (p = 0.041) average real variability, and diastolic blood pressure (p = 0.035) weighted standard deviation. Significant decreases were noted in nighttime diastolic blood pressure time rate variability (p = 0.007). Positive airway pressure treatment resulted in a significant decrease in blood pressure variability, suggesting a clinically significant improvement of sympathetic nerve activity in youth with obesity and sleep-disordered breathing. IMPACT: Cardiovascular variability, as measured by blood pressure variability, is improved in children following positive airway pressure treatment. Our novel findings of improved blood pressure time rate variability are the first described in the pediatric literature. Future studies aimed at analyzing target organ damage in this patient population will allow for a better understanding as to whether alterations in blood pressure variability translate to decreasing target organ damage in children, as seen in adults.

Visit-to-visit blood pressure variability in patients after acute coronary syndrome

Objective. The aim of the study was to assess the possible association of visit-to-visit blood pressure (BP) variability and the risk of adverse outcomes in hypertensive (HTN) patients after acute coronary syndrome.Design and methods. We analyzed data of 1,456 patients (mean age 65,6 ± 12,2 years, 875 (60,1 %) men) discharged from the hospital after acute coronary syndrome and followed up for 1 year in 4 vascular centers in Moscow, Astrakhan, Kazan and Krasnodar in 2014–2017. BP, heart rate, and adverse events were recorded on the day of discharge and on days 25, 90, 180 and 360 after discharge. The visit-to-visit BP variability was assessed by the VIM coefficient (variation independent of mean).Results. The systolic BP variability was 7,81 ± 0,226 mm Hg, diastolic BP variability was 9,89 ± 0,577 mm Hg during follow-up. In total, 110 deaths from any cause, 63 coronary deaths, 130 repeated non-fatal coronary events, 33 ischemic strokes were recorded. A decrease in BP variability was associated with the dihydropyridine calcium antagonists (10,21 ± 6,45 and 7,99 ± 4,70 mm Hg, p = 0,024) and thiazide diuretics (10,34 ± 6,59 and 7,63 ± 9,63 mm Hg, p = 0,049). Multivariate analysis showed that high long-term variability of BP is a more significant factor associated with the overall mortality rate than the initial severity of HTN and even the fact of achieving target BP. The risk of ischemic stroke in patients with HTN was associated with factors such as atrial fibrillation, heart failure, a history of stroke, and high visit-to-visit BP variability.Conclusions. Visit-to-visit BP variability is an important characteristic of BP control and is associated with the risk of death from any causes and stroke in patients with coronary heart disease.

Long-term outcomes of renal denervation and related sex characteristics: data from a three-year follow-up

Aim. To study the long-term outcomes of renal denervation (RDN) within 3-year follow-up with an assessment of blood pressure (BP) changes, the severity of target organ damage and the levels of pro- and anti-inflammatory cytokines in patients with resistant hypertension (RH), taking into account sex characteristics.Material and methods. A total of 42 patients with RH were examined at baseline, 1, 2, and 3 years after RDN on the background of antihypertensive therapy. Twenty-four-hour BP monitoring, echocardiography, assessment of creatinine level and estimated glomerular filtration rate (eGFR), as well as determination of some cytokines (interleukin (IL)-1β, 6, 10, tumor necrosis factor-α) were performed.Results. There was a persistent BP decrease in men and women for three years compared with the initial level by an average of 17 [4; 31]/10 [0; 18] mm Hg (p&lt;0,05). Decrease in BP variability from 17,9±5,1 to 15,2±3,6 mm Hg was observed mainly by means of women, while the decrease in left ventricular mass from 250,4±64,0 to 229,3±61,9 g was mainly by means of men. Creatinine level was unchanged, while eGFR decreased from 78,8±16,1 to 74,5±20,3 ml/ min/1,73 m2 over 3 years; the mean eGFR decline was 1,4 ml/min/1,73 m2 in year. All studied cytokines tended to decrease regardless of sex: tumor necrosis factor-α — from 2,1 [1,2; 77] to 2,1 [1,7; 2,6] pg/ml (p=0,022); IL-1β — from 2,2 [1,5; 2,4] to 1,6 [1,1; 1,5] pg/ml (p=0,034); IL-6 — from 3,8 [1,6; 4,9] to 2,8 [1,8; 3,0] pg/ml (p&gt;0,05), IL-10 — from 5,8 [3,2; 8,2] to 2,8 [2,6; 2,9] pg/ml (p=0,000), correlating with IL-6 dynamics.Conclusion. Three years after RDN, there is a persistent decrease in mean 24-hour BP, regardless of sex. In women, a more pronounced BP variability decrease is observed, while in men — regression of left ventricular mass. There is no significant decrease in eGFR in the long-term period. The decrease in proinflammatory cytokines maintains, and in some cases becomes more pronounced within three years after RDN.

How to Choose the Optimal Single-Pill Combination of the First-Line Antihypertensive Drugs? The Benefits of Amlodipine and Telmisartan Combination

In patients with arterial hypertension (AH), an extremely important measure of the effectiveness of antihypertensive drugs (AHD) is not only a direct decrease in blood pressure (BP), but also its stable control throughout the 24 hours, preventing excessive morning surge and increased BP variability, which in turn are recognized cardiovascular risk factors. Currently, in the vast majority of hypertensive patients, the main antihypertensive therapy approach is using single-pill combinations (SPC) of AHD. Among the first-line combinations for a wide range of patients with AH and no special clinical conditions is amlodipine/telmisartan SPC. Distinctive features of these drugs, on the one hand, are unique pharmacological properties, consisting in an ultra-long antihypertensive effects, superior to other AHD in their classes; and on the other hand, there is an large body of evidence from numerous clinical trials confirming their high antihypertensive and target-organ protective potential as well as excellent capabilities in cardiovascular risk reduction. To assess the AHD effectiveness extent, several parameters have been proposed, of which the most rational and useful is the smoothness index, calculated using the ambulatory blood pressure monitoring data. Smoothness index describes both the degree of BP reduction and its distribution during the monitoring period. This index inversely associates with the changes in BP variability, and has predictive value in relation to the hypertension-mediated organ damage regression during different antihypertensive regimens. Amlodipine/telmisartan SPC has also been studied in many trials, including comparative ones with other AHD. In these works its direct powerful antihypertensive effect and a pronounced beneficial impact on the smoothness index have been proved, demonstrating stable BP control throughout the 24 hours (especially in the most dangerous morning hours), and also a decrease in BP variability. Therefore, amlodipine/telmisartan SPC can effectively reduce cardiovascular risk and improve prognosis in patients with AH.

High Blood Pressure Variability is an Additional Cardiovascular Risk Factor

Blood pressure (BP) is a highly variable physiological indicator. Most people have BP changes within 40-50 mmHg during the day. Various external factors (from the patient’s position during BP measurement to poor adherence to therapy and abuse of short-acting antihypertensive drugs) affect the assessed indicators. Evaluation of the average daily, intra-visit, as well as long-term ("from visit to visit") BP variability is used in clinical practice. In the past twenty years a number of major studies demonstrated that increased BP variability is an independent prognostic factor that increases the risk of cardiovascular complications. The largest meta-analysis of 41 studies showed that an increase in long-term BP variability was associated with 15% and 18% increase in total and cardiovascular mortality, respectively. According to the IDHOCO project, the threshold coefficient of variation for day-today variability is &gt;11.0/12.8. Different groups of antihypertensive drugs have an uneven effect on BP variability. Consistent data from ASCOT-BPLA, X-CELLENT and ACCOMPLISH studies indicate that among the main groups of antihypertensive drugs, calcium antagonists, mainly amlodipine, have the greatest potential for the variability reduction. A decrease in BP variability, as shown in a post-hoc analysis of CAMELOT and PREVENT studies, has a positive effect on the incidence of major adverse cardiac events (MACE). Thus, the BP variability is an important indicator that reflects the prognosis in hypertensive patients. BP variability reduction can be considered as one of the independent goals of therapy. Calcium antagonists can be considered as first-line drugs for patients with high BP variability.

Cardiovascular and autonomic response induced by a 20-week military training programme in young healthy South African males

Background. Studies investigating the relationship between exercise and haemodynamic regulation conducted in older caucasian and blackAfrican populations suggest that lifestyle modification is effective in the management of numerous disease processes. There are few longtermstudies in young healthy populations and even less is known about the influence of habitual exercise on autonomic and haemodynamicvariables in young black African subjects.Objective. To investigate the benefit of prolonged exercise on cardiovascular and haemodynamic variables in young healthy black African males.Methods. Fifty-five healthy male volunteers between 18 and 22 years of age participated in this prospective 20-week medium- to highintensityexercise intervention study with a self-control design. The Finometer Pro (Finapres Medical Systems, the Netherlands) was usedfor non-invasive data sampling of a number of cardiovascular and autonomic variables. Results were generated by computer algorithm andwere analysed using non-parametric Wilcoxon signed rank tests.Results. Significant (p&lt;0.05) cardiovascular changes included an increase in aerobic capacity, stroke volume, cardiac output and ejectionfraction, and a decrease in diastolic blood pressure and heart rate. There was a significant decrease in total peripheral resistance andascending aorta impedance. Systolic blood pressure, mean arterial pressure and arterial compliance remained unchanged, while the decreasein blood pressure variability was not statistically significant (p&gt;0.05).Conclusion. The measured changes suggest a favourable response to exercise and imply that habitual exercise may be an important lifestylemodification for reducing the risk of cardiovascular disease in young black African males.

Long-term changes in blood pressure control in elementary school-aged children with sleep-disordered breathing

ObjectiveIn adults sleep-disordered breathing (SDB) has been associated with impaired baroreflex control of blood pressure (BP), which has been linked to increased cardiovascular morbidity. In children, the long-term effects of SDB on baroreflex sensitivity (BRS) and BP variability (BPV) are unknown. MethodsChildren previously diagnosed with SDB (n=40) and 20 nonsnoring controls aged 11–16y underwent overnight polysomnography with continuous BP measurement, four years after the original diagnosis. At follow-up, SDB was categorized as resolved (absence of snoring and obstructive apnea hypopnea index (OAHI)⩽1) or unresolved (continued to snore or had an OAHI>1). BRS and BPV were calculated using cross-spectral analysis and power spectral analysis, respectively. ResultsOnly children with resolved obstructive sleep apnea (OSA) at follow-up demonstrated an increase in BRS from 9.7±3(msmmHg−1) at baseline to 11.8±4(msmmHg−1) at follow-up (P=.03). However, children with all severities of both resolved and unresolved SDB showed a significant decrease in BPV from baseline to follow-up (a decrease in total power BPV (P<.05) and a shift in BPV spectra away from respiratory-related frequencies (increased low-frequency/high-frequency [LF/HF] ratio, P<.01). The change in OAHI was the sole determinant of change in BRS, HF power, and LF/HF ratio. ConclusionsImprovement in SDB was associated with improved BP control, regardless if SDB was treated or spontaneously resolved four years after initial diagnosis. Our findings highlight the importance of monitoring children to ensure improvement of SDB and reduce the risk for cardiovascular morbidity in the future.

Baroreflex Sensitivity after Adenotonsillectomy in Children with Obstructive Sleep Apnea during Wakefulness and Sleep

Children with obstructive sleep apnea have blunted baroreflex sensitivity and increased blood pressure variability. The aim of the study was to test the hypothesis that treatment of sleep apnea by adenotonsillectomy results in significant improvement of baroreflex sensitivity, lowering of blood pressure and blood pressure variability and increase vagal heart rate modulation. One hundred ninety-four children aged 9.6 ± 2.3 years were enrolled; 133 had obstructive sleep apnea and 61 were healthy controls. For children with sleep apnea, polysomnography with 3-lead electrocardiography and continuous blood pressure was performed before adenotonsillectomy, then 6 weeks and 6 months postoperatively. Controls underwent the same assessment at study entry and 6 months later. Spontaneous baroreflex sensitivity was measured in the time and frequency domains. Data analyses were performed for available and complete cases. Children with sleep apnea experienced postoperatively an increase in baroreflex sensitivity and decrease in blood pressure variability during wakefulness and sleep. A decrease in blood pressure during sleep and in heart rate during wakefulness was also measured. The improvement in baroreflex sensitivity was predicted by the change in the apnea-hypopnea and arousal indices. A normal pattern of rising baroreflex sensitivity during the night was restored in children with severe apnea after surgery. However, baroreceptor sensitivity did not completely normalize after treatment. Treatment of obstructive sleep apnea in children by adenotonsillectomy is associated with gradual improvement in known risk factors for cardiovascular disease. Complete normalization of baroreceptor sensitivity was not achieved 6 months postoperatively.

Effects of Angiotensin II Type 1 Receptor Blocker on Blood Pressure Variability and Cardiovascular Remodeling in Hypertensive Patients on Chronic Peritoneal Dialysis

Aims: In this study, we examined whether addition of an angiotensin II type 1 receptor blocker (ARB), candesartan or valsartan, to conventional antihypertensive treatment could improve blood pressure (BP) variability in hypertensive patients on peritoneal dialysis. Methods: 45 hypertensive patients on chronic peritoneal dialysis therapy were randomly assigned to the ARB treatment groups either by candesartan (n = 15) or valsartan (n = 15), or the control group (n = 15). At baseline and 6 months after the treatment, 24-hour ambulatory BP monitoring, echocardiography, and measurement of brachial-ankle pulse wave velocity (baPWV) were performed. Results: After the 6 months of treatment, 24-hour ambulatory BP values were similarly decreased in both the control group and ARB groups. However, short-term BP variability assessed on the basis of the standard deviation of 24-hour ambulatory BP was significantly decreased in the ARB groups, but remained unchanged in the control group. Furthermore, parameters of cardiovascular remodeling assessed by natriuretic peptides, echocardiography, and baPWV were significantly improved in the ARB groups but not in the control group. Conclusion: ARB treatment and control antihypertensive treatment similarly controlled 24-hour ambulatory BP values in hypertensive patients on peritoneal dialysis. However, ARB treatment is beneficial for the suppression of pathological cardiovascular remodeling with a decrease in BP variability.

Synergism of Hydrochlorothiazide and Nifedipine on Blood Pressure Variability Reduction and Organ Protection in Spontaneously Hypertensive Rats

This study was designed to investigate the effects of a hydrochlorothiazide-nifedipine combination on blood pressure (BP), blood pressure variability (BPV), baroreflex sensitivity (BRS), and organ protection in spontaneously hypertensive rats (SHR). The doses used were 10 mg/kg/d for both hydrochlorothiazide and nifedipine, and 10+10 mg/kg/d for the combination of these two drugs. Drugs were mixed into rat chow at the aforementioned doses. SHR were treated for 4 months, and then BP was continuously recorded for 24 h. After the determination of BRS, rats were killed for organ-damage evaluation. It was found that long-term treatment with hydrochlorothiazide, nifedipine or both significantly decreased BP and BPV, enhanced BRS and conferred organ protection in SHR. The combination of hydrochlorothiazide and nifedipine had a significant synergistic effect on BPV reduction, BRS enhancement and organ protection in SHR, whereas no obvious synergism on BP reduction was found. Multiple-regression analysis showed that the decrease in left ventricular and aortic hypertrophy was most closely associated with the decrease in systolic BPV and the increase in BRS, and the amelioration of renal lesions was most closely associated with the increase in BRS. In conclusion, long-term treatment with a combination of hydrochlorothiazide and nifedipine yielded a significantly synergistic effect on BPV reduction, BRS restoration and organ protection in SHR. In addition to BP reduction, the decrease in BPV and the enhancement of BRS may have made important contributions to the observed organ protection.

Reduction of blood pressure variability by combination therapy in spontaneously hypertensive rats

To test the hypothesis that combination therapy might be a powerful tool to reduce blood pressure variability (BPV) in the treatment of hypertension. In chronic studies, male spontaneously hypertensive rats were given drugs in their rat chow for 18 weeks (n = 9 or 10 for each group of rats). Doses were as follows: atenolol (10 mg/kg per day), amlodipine (1 mg/kg per day), a combination of atenolol and amlodipine (2.5 + 0.25, 5 + 0.5, and 10 + 1 mg/kg per day), hydrochlorothiazide (8 mg/kg per day), enalapril (3.2 mg/kg per day), and a combination of hydrochlorothiazide and enalapril (2 + 0.8, 4 + 1.6, and 8 + 3.2 mg/kg per day). In acute studies, drugs were perfused through the left femoral vein in conscious rats. In chronic studies, compared with monotherapy, the combinations of two antihypertensive drugs were more effective in reducing the blood pressure (BP), BPV, and organ damage. The indexes of organ damage were all positively related to BP and/or BPV. In acute studies, the constant infusion of phenylephrine (6.25 microg/kg per min) markedly increased the BP, but showed no significant effects on BPV. The infusion of a combination of atenolol and amlodipine (62.5 + 6.25 microg/kg per min) or a combination of hydrochlorothiazide and enalapril (500 + 200 microg/kg per min) significantly reduced the BP and BPV; moreover, a significant reduction in BPV was still found when the rat's BP was restored to control levels by a concomitant infusion of phenylephrine. Combination therapy may be a powerful and useful tool for BPV reduction in the treatment of hypertension. In addition to the BP reduction, the decrease in BPV may contribute significantly to the prevention of organ damage in hypertension.

La variabilité de la fréquence cardiaque et de la tension artérielle comme indicateurs du bloc sensitif lors de l’analgésie péridurale pour le travail obstétrical

To evaluate the correlation between the progression of somatosensory blockade and changes in autonomic outflow following the onset of labour epidural analgesia. Twelve labouring parturients consented to participate in the study. Baseline electrocardiogram, blood pressure (BP) and respiratory rate were recorded for ten minutes. The epidural consisted of 0.125% bupivacaine with 50 microg of fentanyl (total volume 20 mL). Measurements were repeated for ten minutes after initiation of the block. The level of sensory block was measured bilaterally with loss of sensation to ice at two-minute intervals. Wavelet transform was used to obtain heart rate (HR) and BP variability every two minutes following the loading dose of epidural medication. High frequency power of HR variability was used to assess changes in parasympathetic activity. The total power of BP variability was used to assess changes in sympathetic activity. A nonparametric repeated measures ANOVA was used for the variability data, and a Spearman rank correlation test was used to evaluate the relationship between the sensory block and HR and BP variability. The sensory block progressed to T9 at ten minutes post-epidural and was the mirror image of the decrease in total power of BP variability. High frequency power of HR variability increased to a plateau at six minutes post-epidural. A significant correlation was found between the increase in sensory block and the observed decrease in BP variability (r = -1.000, P = 0.0028). In this study of labouring parturients, BP variability correlated with the progression of both sympathetic and somatosensory block following epidural anesthesia, while HR variability was shown to be a surrogate marker of increased parasympathetic activity.

Blood pressure variability, baroreflex sensitivity and organ damage in spontaneously hypertensive rats treated with various antihypertensive drugs

Besides blood pressure, blood pressure variability and baroreflex sensitivity maybe important factors determining organ damage in hypertension. This study was designed to investigate the effects of various antihypertensive drugs on blood pressure and blood pressure variability reductions, baroreflex sensitivity, and target organ damage in spontaneously hypertensive rats (SHR). The dose is 20 mg/kg/day for atenolol, and 10 mg/kg/day for nifedipine, irbesartan and hydrochlorothiazide. We used relatively low doses of drugs to avoid a very remarkable normalization of blood pressure in the treatment, which would make it much difficult to distinguish the contribution of blood pressure variability and baroreflex sensitivity to organ protection from that of blood pressure. Drugs at the aforementioned doses were mixed into rat chow. SHR were treated for 4 months. Blood pressure was then continuously recorded for 24 h. After the determination of baroreflex sensitivity, rats were killed for organ-damage evaluation. It was found that long-term treatment with atenolol, nifedipine, irbesartan or hydrochlorothiazide all markedly reduced blood pressure variability, enhanced baroreflex sensitivity, and produced significant organ protection. Compared with blood pressure level, blood pressure variability and baroreflex sensitivity values showed a much closer or similar relationship with organ-damage parameters in every treatment group of rats. Multiple-regression analysis showed that the decrease in left ventricular hypertrophy, the decrease in aortic hypertrophy and the amelioration in renal lesion were all most closely correlated with the increase in baroreflex sensitivity and the decrease in systolic blood pressure variability. In conclusion, long-term treatment with atenolol, nifedipine, irbesartan or hydrochlorothiazide produced organ protection in SHR. Besides the blood pressure reduction, the decrease in blood pressure variability and the restoration of baroreflex sensitivity may contribute to this organ protection.

Effects of Long-Term Treatment with Candesartan on Hemodynamics and Organ Damage in Spontaneously Hypertensive Rats

This study was designed to investigate the effects of candesartan on blood pressure (BP) and blood pressure variability (BPV) reductions, baroreflex sensitivity (BRS) amelioration, and organ protection in spontaneously hypertensive rats (SHR). Studies were performed in two groups of SHR (n = 13 for control rats; and n = 20 for candesartan-treated rats) and one group of WKY rats (n = 13). Candesartan (3 mg /kg/d) was given in rat chow for 4 months. BP was then continuously recorded for 24 hours in conscious state. After the determination of BRS, rats were killed for organ-damage evaluation. Long-term treatment with candesartan significantly reduced BP and BPV expressed by both standard deviation and variation coefficient of BP, enhanced BRS and produced obvious organ protection. Compared with BP level, BPV and BRS values showed a closer or similar relationship with organ-damage parameters in SHR. Multiple regression analysis showed that the decrease in left ventricular hypertrophy was most closely associated with the increase in BRS, whereas the decrease in aortic hypertrophy was most closely associated with the decrease in 24-hour systolic BPV, and the amelioration in renal lesions, with the increase in BRS and the decrease in 24-hour systolic BPV. long-term treatment with candesartan results in organ protection in SHR. Besides BP reduction, the decrease in BPV and the restoration of BRS are significantly related to this organ protection.