Directly observed therapy for resistant/refractory hypertension diagnosis and blood pressure control

OBJECTIVE

To test the impact of directly observed therapy (DOT) at hospital for checking not only adherence/diagnosis in patients with resistant (RHTN) and refractory (RefHTN) hypertension but also blood pressure (BP) control after hospital discharge.

METHODS

During 2 years, Brazilian patients with clinical suspicion of RHTN/RefHTN after several attempts (≥3) to control BP in the outpatient setting were invited to perform DOT (including low-sodium diet and supervised medications intake) at the hospital. RHTN and RefHTN were categorised using standard definitions. After hospital discharge, we evaluated the BP values and the number of antihypertensive drugs prescribed by physicians who were not involved with the investigation.

RESULTS

We studied 83 patients clinically suspected for RHTN (31%) and RefHTN (69%) (mean age: 53 years; 76% female; systolic BP 177±28 mm Hg and diastolic BP 106±21 mm Hg; number of antihypertensive drugs: 5.3±1.3). DOT confirmed RHTN in 77%, whereas RefHTN was confirmed in only 32.5%. The number of antihypertensive drugs reduced to 4.5±1.3 and systolic/diastolic BP at hospital discharge reduced to 131±17 mm Hg/80±12 mm Hg. After hospital discharge, systolic BP remained significantly lower than the last outpatient visit prehospital admission (delta changes (95% CI): 1 month: -25.7 (-33.8 to -17.6) mm Hg; 7 months: -27.3 (-35.5 to -19.1) mm Hg) despite fewer number of antihypertensive classes (1 month: -1.01 (-1.36 to -0.67); 7 months: -0.77 (-1.11 to -0.42)). Similar reductions were observed for diastolic BP.

CONCLUSIONS

DOT at hospital is helpful not only in confirming/excluding RHTN/RefHTN phenotypes, but also in improving BP values and BP control and in reducing the need for antihypertensive drugs after hospital discharge.

Differential influences of dietary sodium on blood pressure regulation based on race and sex

There are clear differences between men and women, and differences among races, in the incidence and prevalence of hypertension. Furthermore, there is extensive inter-individual variability among humans in the extent to which sodium ingestion alters blood pressure. Orthostatic intolerance and orthostatic hypotension are more common in women; these are often treated with a high salt diet, which has variable efficacy in increasing blood volume and blood pressure. Conversely, people with certain forms of hypertension are often counseled to decrease their sodium intake. Non-Hispanic Black men and women have higher rates of hypertension compared to non-Hispanic White men and women and other racial/ethnic groups. In aggregate, Black women appear to have better orthostatic tolerance than White women. In the present paper, we summarize and evaluate the current evidence for mechanisms of blood pressure regulation in men and women, as well as differences between Black and White groups, with a focus on cardiovascular responses to salt and differences among these groups. We also provide a brief review of factors that are not traditionally considered to be "biological" - such as socio-economic disparities resulting from historic and contemporary inequity across racial groups. These non-biological factors have direct and substantial influences on cardiovascular mechanisms, as well as implications for the influences of salt and sodium intake on blood pressure and cardiovascular health. We conclude that both biological and socio-economic factors provide critical modulating influences when considering the impacts of sodium on cardiovascular health as functions of race and sex.

The Effects of Short-Term Changes in Sodium Intake on Plasma Marinobufagenin Levels in Patients with Primary Salt-Sensitive and Salt-Insensitive Hypertension

Increased marinobufagenin (MBG) synthesis has been suggested in response to high dietary salt intake. The aim of this study was to determine the effects of short-term changes in sodium intake on plasma MBG levels in patients with primary salt-sensitive and salt-insensitive hypertension. In total, 51 patients with primary hypertension were evaluated during acute sodium restriction and sodium loading. Plasma or serum concentrations of MBG, natriuretic pro-peptides, aldosterone, sodium, potassium, as well as hematocrit (Hct) value, plasma renin activity (PRA) and urinary sodium and potassium excretion were measured. Ambulatory blood pressure monitoring (ABPM) and echocardiography were performed at baseline. In salt-sensitive patients with primary hypertension plasma MBG correlated positively with diastolic blood pressure (ABPM) and serum NT-proANP concentration at baseline and with serum NT-proANP concentration after dietary sodium restriction. In this subgroup plasma MBG concentration decreased during sodium restriction, and a parallel increase of PRA was observed. Acute salt loading further decreased plasma MBG concentration in salt-sensitive subjects in contrast to salt insensitive patients. No correlation was found between plasma MBG concentration and left ventricular mass index. In conclusion, in salt-sensitive hypertensive patients plasma MBG concentration correlates with 24-h diastolic blood pressure and dietary sodium restriction reduces plasma MBG levels. Decreased MBG secretion in response to acute salt loading may play an important role in the pathogenesis of salt sensitivity.

Female Sex, a Major Risk Factor for Salt-Sensitive Hypertension

PURPOSE OF REVIEW

High dietary salt is a significant contributor to essential hypertension in clinical populations. However, although clinical studies indicate a higher prevalence of salt sensitivity in women over men, knowledge of salt-sensitive mechanisms is largely restricted to males, and female-specific mechanisms are presently being elucidated.

RECENT FINDINGS

Male-specific mechanisms of salt-sensitive hypertension are well published and predominantly appear to involve dysfunctional renal physiology. However, emerging novel evidence indicates that aldosterone production is sex-specifically heightened in salt-sensitive hypertensive women and female rodent models, which may be regulated by intra-adrenal renin-angiotensin system activation and sex hormone receptors. In addition, new evidence that young females endogenously express higher levels of endothelial mineralocorticoid receptors (MRs) and that endothelial MR is a crucial mediator of endothelial dysfunction in females indicates that the aldosterone-endothelial MR activation pathway is a novel mediator of salt-sensitive hypertension. Heightened aldosterone levels and endothelial MR expression provide a 2-fold sex-specific mechanism that may underlie the pathology of salt-sensitive hypertension in women. This hypothesis indicates that MR antagonists may be a preferential treatment for premenopausal women diagnosed with salt-sensitive hypertension.

Relationship of Sodium Intake and Blood Pressure Varies With Energy Intake: Secondary Analysis of the DASH (Dietary Approaches to Stop Hypertension)-Sodium Trial

Dietary Na recommendations are expressed as absolute amounts (mg/d) rather than as Na density (mg/kcal). Our objective was to determine whether the strength of the relationship of Na intake with blood pressure (BP) varied with energy intake. The DASH (Dietary Approaches to Stop Hypertension)-Sodium trial was a randomized feeding trial comparing 2 diets (DASH and control) and 3 levels of Na density. Participants with pre- or stage 1 hypertension consumed diets for 30 days in random order; energy intake was controlled to maintain body weight. This secondary analysis of 379 non-Hispanic black and white participants used mixed-effects models to assess the association of Na and energy intakes with BP. The relationships between absolute Na and both systolic and diastolic BP varied with energy intake. BP rose more steeply with increasing Na at lower energy intake than at higher energy intake (P interaction<0.001). On the control diet with 2300 mg Na, both systolic and diastolic BP were higher (3.0 mm Hg; 95% confidence interval, 0.2-5.8; and 2.7 mm Hg; 95% confidence interval, 1.0-4.5, respectively) among those with lower energy intake (higher Na density) than among those with higher energy intake (lower Na density). The association of Na with systolic BP was stronger at lower levels of energy intake in both blacks and whites (P<0.001). The association of Na and diastolic BP varied with energy intake only among blacks (P=0.001). Sodium density should be considered as a metric for expressing dietary Na recommendations.

The salt-taste threshold in untreated hypertensive patients

Background

The salt-taste threshold can influence the salt appetite, and is thought to be another marker of sodium intake. Many studies have mentioned the relationship between the sodium intake and blood pressure (BP). The aim of this study was to evaluate the relationship between the salt-taste threshold and urinary sodium excretion in normotensive and hypertensive groups.

Methods

We analyzed 199 patients (mean age 52 years, male 47.3%) who underwent 24-h ambulatory BP monitoring (ABPM). Hypertension was diagnosed as an average daytime systolic BP of ≥135 mmHg or diastolic BP of ≥85 mmHg by the ABPM. We assessed the salt-taste threshold using graded saline solutions. The salt-taste threshold, 24-h urinary sodium and potassium excretion, and echocardiographic data were compared between the control and hypertensive groups.

Results

The detection and recognition threshold of the salt taste did not significantly differ between the control and hypertensive groups. The 24-h urinary sodium excretion of hypertensive patients was significantly higher than that of the control group (140.9 ± 59.8 vs. 117.9 ± 57.2 mEq/day, respectively, p = 0.011). Also, the urinary sodium-potassium ratio was significantly higher in the hypertensive patients. There was no correlation between the salt-taste threshold and 24-h urinary sodium excretion.

Conclusions

The salt-taste threshold might not be related to the BP status as well as the 24-h urinary sodium excretion.

Spatial analysis of gender variation in the prevalence of hypertension among the middle-aged and elderly population in Zhejiang Province, China

Background

Previous studies have shown that there may be gender disparities in the prevalence of hypertension; however, these studies do not address the spatial information contained in the sample which may limit the analytical results. Our study extends the existing Shared Component Model (SCM) and compares its utility with a logistic regression model to evaluate the significance of spatial information for identifying risk factors for hypertension and other non-rare diseases.

Methods

A total of 1267 residents aged 45 years of age and over were included in our study, of which 48.1 % were males. The overall prevalence of hypertension was 33.2 %, with females experiencing a higher prevalence than males (35.5 % vs. 30.6 %). The research variables included body mass index (BMI), Waist -to-Height Ratio (WHtR), smoking status, alcohol consumption etc. The extended SCM is employed to investigate regional gender variations in the risk of hypertension and assess the gender variation in the middle-aged and elderly populations of Zhejiang Province in eastern China and then its performance is compared with that of a traditional multiple logistic regression model.

Results

Our SCM analysis determined that the spatial pattern of hypertension risk for the middle-aged and elderly populations of Zhejiang Province in eastern China is quite different for males and females. Furthermore, Waist -to-Height Ratio (WHtR) continues to be a simple and effective predictor of hypertension risk for males at the regional level.

Conclusions

We believe that the extended SCM spatial model is a useful tool for identifying risk factors at the regional level.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-016-3121-y) contains supplementary material, which is available to authorized users.

Association Between Family History and Hypertension Among Chinese Elderly

This study aimed to evaluate the association between family history and prevalence of hypertension among Chinese community elderly, and also explore the gender difference. A population-based cross-sectional study was conducted in Miyun district of Beijing, in 2014. The family history information was obtained from each subject and was divided into 3 categories, no family history (FH0), 1 generation of first-degree relatives with hypertension (FH1), and 2 generations of first-degree relatives with hypertension (FH2). The prevalence of hypertension was 53.0%. Participants with positive family history had a significantly higher prevalence of hypertension (67.5%, 95% CI: 63.3-71.7) than those without (47.9%, 95% CI: 45.2-50.6), and even among participants without hypertension, the blood pressure levels were higher with positive FH. Multiple logistic regression analysis showed that a significantly linear-trend increase in hypertension according to family history of first degree relative numbers was observed in both genders (P for trend < 0.001). This study suggests that family history had not only a significant but also graded association with hypertension and with blood pressure levels, and this association exists even among those without hypertension.

25-Hydroxyvitamin D is associated with plasma renin activity and the pressor response to dietary sodium intake in Caucasians

INTRODUCTION

Concentrations of 1,25-hydroxyvitamin D have been positively associated with dietary sodium and salt sensitivity (SS) of blood pressure (BP), and inversely with plasma renin activity (PRA). We investigated the association between PRA and 25-hydroxyvitamin D (25OHD), the most clinically relevant vitamin D metabolite, and whether 25OHD associates with SS of BP in renin phenotypes of hypertension.

METHODS

We performed cross-sectional analyses on 223 Caucasian subjects with hypertension maintained in high and low dietary sodium balance. Subjects were distinguished as having low-renin (LR) or normal-renin (NR) hypertension. Multivariable linear regression was used to evaluate adjusted relationships.

RESULTS

Increasing 25OHD concentrations were inversely associated with PRA (p < 0.05) on both salt diets. Furthermore, 25OHD was associated with SS of BP in LR hypertension (b = 0.62, p = 0.04), but not in NR hypertension (b = 0.06, p = 0.59). In an adjusted multivariable interaction model, renin status (LR vs. NR) was a significant effect modifier of the relationship between 25OHD and SS of BP (p = 0.04).

CONCLUSIONS

Our findings suggest that 25OHD is inversely associated with PRA and positively associated with SS of BP in LR hypertension subjects. These results extend and support prior evidence indicating an interaction between dietary sodium, the RAS, and vitamin D that influences BP in hypertension.

Sex steroid receptors expression and hormone-induced cell proliferation in human osteosarcoma

Sex steroid receptors including estrogen receptors (ER), progesterone receptors (PR), and androgen receptors (AR) have been sporadically reported in human osteosarcoma or its cell lines. Therefore, sex steroids have been considered to play some roles in human osteosarcoma, but no systematic and detailed studies regarding the correlation between the status of these receptors in sarcoma cells and clinicopathological parameters have been reported. We examined the existence of ER, PR and AR in 28 cases of osteosarcoma using immunohistochemistry. We then characterized the potential influence of sex steroids on cell proliferation of osteosarcoma cells using MG-63 human osteosarcoma cell line, which expressed all of these receptors. ER-beta and PR were detected in the great majority of the cases (23 and 24 cases, respectively) but ER-alpha and aromatase were not detected in all the cases, and AR was detected only in eight cases. There was a significant positive correlation between ER-beta and Ki-67 (MIB1) labeling indexes. The absence of aromatase in tumors also suggests the relative importance of concentrations of circulating sex steroids. Proliferation of MG-63 cells was significantly stimulated by estradiol, progesterone, and 5 alpha-dihydrotestosterone (DHT), and was significantly suppressed by the addition of fulvestrant (ICI), mifepristone (RU), and hydroxiflutamide, blockers for ER, PR and AR, respectively. Sex steroids, particularly estrogen and progesterone, are considered to play important roles in the regulation of cell proliferation in human osteosarcoma. In addition, these data suggest the potential for a novel endocrine therapy in osteosarcoma using clinically available inhibitors of progesterone and estrogen actions.

Participation of renal and circulating endothelin in salt-sensitive essential hypertension

Salt sensitivity of blood pressure is a cardiovascular risk factor, independent of and in addition to hypertension. In essential hypertension, a conglomerate of clinical and biochemical characteristics defines a salt-sensitive phenotype. Despite extensive research on multiple natriuretic and antinatriuretic systems, there is no definitive answer yet about the major causes of salt-sensitivity, probably reflecting the complexity of salt-balance regulation. The endothelins, ubiquitous peptides first described as potent vasoconstrictors, also have vasodilator, natriuretic and antinatriuretic actions, depending on their site of generation and binding to different receptors. We review the available data on endothelin in salt-sensitive essential hypertension and conclude that abnormalities of renal endothelin may play a primary role. More importantly, the salt-sensitive patient may have blood pressure-dependency on endothelin in all states of salt balance, thus predicting that endothelin receptor blockers will have a major therapeutic role in salt-sensitive essential hypertension.

The prostaglandin E2 EP1 receptor mediates pain perception and regulates blood pressure

The lipid mediator prostaglandin E2 (PGE2) has diverse biological activity in a variety of tissues. Four different receptor subtypes (EP1-4) mediate these wide-ranging effects. The EP-receptor subtypes differ in tissue distribution, ligand-binding affinity, and coupling to intracellular signaling pathways. To identify the physiological roles for one of these receptors, the EP1 receptor, we generated EP1-deficient (EP1-/-) mice using homologous recombination in embryonic stem cells derived from the DBA/1lacJ strain of mice. The EP1-/- mice are healthy and fertile, without any overt physical defects. However, their pain-sensitivity responses, tested in two acute prostaglandin-dependent models, were reduced by approximately 50%. This reduction in the perception of pain was virtually identical to that achieved through pharmacological inhibition of prostaglandin synthesis in wild-type mice using a cyclooxygenase inhibitor. In addition, systolic blood pressure is significantly reduced in EP1 receptor-deficient mice and accompanied by increased renin-angiotensin activity, especially in males, suggesting a role for this receptor in cardiovascular homeostasis. Thus, the EP1 receptor for PGE2 plays a direct role in mediating algesia and in regulation of blood pressure.

Association between salt sensitivity and target organ damage in essential hypertension

Cardiovascular events occur more frequently in sodium-sensitive patients with essential hypertension; recently, sodium sensitivity was shown to be a cardiovascular risk factor independently of other classic factors such as blood pressure and cigarette smoking This study examined the relationship between salt sensitivity status and target organ damage in hypertensive patients. Ninety-six patients (35 men, 61 women) with moderate essential hypertension were studied for salt sensitivity status and the presence of target organ damage, including hypertensive retinopathy, serum creatinine, creatinine clearance, and urinary albumin excretion (UAE). Four different patterns of left ventricular anatomic adaptation were identified by categorizing patients according to the values of left ventricular mass index and relative wall thickness by the means of echocardiography. Forty-five (47%) patients were shown to be salt-sensitive, in contrast to 51 (53%) salt-resistant subjects. Serum creatinine and UAE were significantly higher in the group of salt-sensitive hypertensives (P < .05 and P < .001, respectively). Left ventricular mass index (LVMI), relative wall thickness (RWT), and left atrial index (LAI) were all significantly higher in the group of salt-sensitive hypertensive patients. Concentric hypertrophy was significantly more prevalent in the salt-sensitive group (37.8% v 11.8%; P < .01). The prevalence of hypertensive retinopathy in the salt-sensitive group was 84.4%, in contrast to 59.6% in the salt-resistant group (P < .01). Multivariate regression analysis revealed salt sensitivity as a significant predictor of LVMI, RWT, and UAE, independently of age, body mass index, and mean blood pressure. In conclusion, salt-sensitive hypertensive patients are more prone to develop severe hypertensive target organ damage that may enhance their risk of renal and cardiovascular morbidity.

Hypertension in women: current understanding of gender differences

High blood pressure is a major individual and public-health issue because of its wide prevalence and associated complications. More women than men have hypertension, but until recently, women have been relatively underrepresented in clinical trials. Gender differences in the physiology, genetics, and treatment benefit of hypertension have been noted in several studies that have included women. These findings have raised concerns about the generalizability of the results of previous investigations to women. The currently available information regarding gender differences and similarities and the results of hypertension treatment trials in women are reviewed herein. These studies suggest that, although gender differences exist, women benefit significantly when they receive therapy to normalize blood pressure.

Blunted parasympathetic modulation in salt-sensitive patients with essential hypertension: evaluation by power-spectral analysis of heart-rate variability

OBJECTIVE

To evaluate autonomic nervous function by power-spectral analysis of heart-rate variability in salt-sensitive and non-salt-sensitive patients with essential hypertension under the conditions of low and high salt intakes.

DESIGN AND METHODS

The blood pressures, heart rates, and electrocardiogram R-R intervals of 20 hypertensive patients were measured at intervals of 30 min during a 24 h period using a portable recorder (TM-2425) on the last day of the high- (250 mmol NaCl/day) and low-salt (25 mmol NaCl/day) diet periods. The patients whose 24 h average mean blood pressures were increased by more than 10% by the high salt intake were defined as salt-sensitive (n = 10); the other patients were considered non-salt-sensitive (n = 10). Power-spectral analysis of R-R intervals was performed to obtain the low-frequency component (0.05-0.15 Hz) and the high-frequency component (0.15-0.40 Hz).

RESULTS

The average 24 h blood pressure in the salt-sensitive patients was increased by the high salt intake [by 19.1 +/- 2.0/9.1 +/- 0.8 mmHg (mean +/- SEM)], whereas the heart rate did not change. In contrast, the increase in 24 h blood pressure in the non-salt-sensitive patients caused by the high salt intake was not significant and the heart rate was decreased significantly by the high salt intake (by 5.9 +/- 1.4 beats/min). The high-salt diet increased significantly the high-frequency component and decreased the low-frequency:high-frequency component ratio both during the daytime and during the night-time for the non-salt-sensitive patients. In contrast, the high-frequency component and the night-time low-frequency: high-frequency component ratio of the salt-sensitive patients did not respond to dietary salt manoeuvres.

CONCLUSIONS

Responses of the parasympathetic and sympathetic nervous systems to dietary salt manoeuvres were blunted in salt-sensitive patients. These altered modulations of the autonomic nervous system may contribute to the salt sensitivity of the blood pressure in patients with essential hypertension.

Cosegregation of the new region on chromosome 3 with salt-induced hypertension in female F2 progeny from stroke-prone spontaneously hypertensive and Wistar-Kyoto rats

1. We investigated candidate loci for salt-sensitive high blood pressure (BP) in F2 progeny from crossing Wistar-Kyoto and stroke-prone spontaneously hypertensive rats. 2. In female F2 progeny, systolic and diastolic BP on the 12th day and the seventh month after salt loading was strongly linked with the D3Mgh12 and D3Mgh6 loci on chromosome 3, respectively. 3. These loci were linked with BP only in female F2 progeny, not in males. 4. These results indicate that hormonal factors may influence salt sensitivity, particularly with respect to gender differences.

Lower leg high-intensity resistance training and peripheral hemodynamic adaptations

High-intensity resistance (HIR) training has been associated with muscle hypertrophy and decreased microvascular density that might produce a blood flow limitation. The effect of HIR training on lower leg maximal blood flow and minimum vascular resistance (Rmin) during reactive hyperemia were investigated in 7 healthy males. The gastrocnemius-soleus muscles of one leg were trained using maximal isokinetic concentric contractions for 4 weeks; the nontrained leg was the control. Lower leg blood flow was measured by venous occlusion plethysmography. Lower leg muscle volume was determined using magnetic resonance imaging. Peak isokinetic torque increased in both the trained (T) and nontrained (NT) legs (p < .05). Lower leg muscle volume increased by 2% in the T leg only (p < .05). In the T leg, maximal blood flow decreased and Rmin increased (p < .05); no hemodynamic change was detected in the NT leg. It is concluded that HIR training of the calf muscles is associated with a decrease in hyperemia-induced blood flow; thereby, indicating a blood flow limitation to the calf muscles.

Comparison of salt sensitivity of male and female F2 progeny from crosses between WKY and SHRSP rats

1. The present study compared the salt sensitivity of male and female F2 progeny obtained from crosses between Wistar-Kyoto/Izumo rats and stroke-prone spontaneously hypertensive rats (SHRSP A3b/Izm) after salt loading for 7 months. 2. Average systolic blood pressure in male F2 progeny was 10 mmHg higher than that of female F2 progeny at 5 months without salt loading. 3. The blood pressure in male F2 progeny was raised significantly 2 months after salt loading, but there was no further significant change in blood pressure even though salt loading was continued for 5 months. 4. In female F2 progeny, however, a significant change in systolic blood pressure was observed 1 month after salt loading and there was a further significant rise in blood pressure over 6 months. 5. Angiotensin I-converting enzyme and RR1023 loci were strongly linked to systolic and diastolic blood pressures in the male but not the female F2 progeny after salt loading for 7 months. 6. We therefore speculate that the hormonal difference between sexes might influence salt sensitivity in the SHRSP.

Salt restriction in hypertension

Salt has had a long and controversial history. It is not known when man began to use salt in his diet, but it is logical to believe that salt has always been a part of human diet though we do not have scientific proof for this. Restriction of salt in hypertensive patients has been a popular measure adopted world wide. This paper examines the usefulness of salt restrictions and the effect it would cause. Most cases of hypertension are symptomless--using a therapy which drastically affects a patients food habits is a poor strategy to ensure compliance. We conclude that salt restriction is not very useful and probably harmful in some patients. Additionally it reduces the quality of life.