Aldosterone-to-renin ratio and nocturnal blood pressure decline assessed by self-measurement of blood pressure at home: the Ohasama Study

Obesity in Hypertensive Patients Is Characterized by a Dawn Phenomenon in Systolic Blood Pressure Values and Variability

One of the causes of hypertension is excess weight gain, which can also affect the course of this disease. Both the diagnosis and management of hypertension commonly use ambulatory blood pressure monitoring; the results of which correlate more strongly with cardiovascular diseases and cardiovascular death than office blood pressure monitoring. We evaluated blood pressure values and their variability from hour to hour to see if and when they differed between hypertensive patients with and without obesity. The study included 1345 patients who underwent 24 h ambulatory blood pressure monitoring and then were divided into groups according to body mass index and waist circumference. The obtained data were analyzed according to the subjects' wake-up time, and short-term blood pressure variability parameters were calculated as the mean of the absolute values of the differences between consecutive measurements. The systolic blood pressure in obese subjects was significantly higher between 1 and 5 h before waking than in normal-weighted individuals. In turn, the variability in systolic and diastolic blood pressure was higher with increasing body mass index. The difference in systolic blood pressure values and blood pressure variability was most prominent in the last 5 h of sleep in obese patients.

Association of Nighttime Systolic Blood Pressure With Left Atrial-Left Ventricular–Arterial Coupling in Hypertension

Objective

Hypertension (HT) induces left atrial (LA) and left ventricular (LV) dysfunction, and an increase in arterial stiffness. In this study, we investigated the association between LA-LV–arterial coupling and nighttime systolic blood pressure (BP) as well as BP circadian rhythm in essential hypertension.

Methods

We enrolled 290 HT patients. All subjects were evaluated by 2- dimensional speckle tracking echocardiography (2DSTE), ambulatory 24 h BP monitoring (ABPM), and brachial–ankle pulse wave velocity (PWV). According to BP patterns, these patients were divided into two groups, which included dippers (n = 111), patients with a >10% reduction in BP at nighttime; non-dippers (n = 179), patients with a <10% reduction in BP at nighttime. 2D-STE based LA and LV strains were studied and the following parameters were measured, LV global longitudinal strain (GLS), LA reservoir strain (LA_S−S), LA conduit strain (LA_S−E), and LA booster pump strain (LA_S−A). LA stiffness index (LASI) defined as the ratio of E/e′ to LA_S−S, and PWV-to-GLS ratio (PWV/GLS) were calculated to reflect LA-LV–arterial coupling. Furthermore, we also explored the correlation between LASI (or PWV/GLS) and ambulatory blood pressure indexes.

Results

Left atrial stiffness index was significantly higher in non-dippers [0.29 (0.21, 0.41)] than in dippers [0.26 (0.21, 0.33)] (P < 0.05). PWV/GLS was significantly higher in non-dippers [−80.9 (−69.3, −101.5)] than in dippers [−74.2 (−60.2, −90.6)] (P < 0.05). LA_S−S, LA_S−E, LA_S−A,and LV GLS were significantly lower in non-dippers than in dippers (P < 0.05). Multivariate linear regression analysis revealed that nighttime systolic BP was independently correlated with LASI and PWV/GLS, even adjusted for multiple clinical risk factors, LVMI, and LVEF.

Conclusions

The dipping pattern of BP was related to the abnormalities of myocardial mechanics and LA-LV–arterial coupling. However, absolute nocturnal systolic BP value maybe more important than BP circadian profile in the progression of abnormal LA-LV–arterial coupling.

Effects of blood pressure and heart rate circadian rhythms on left atrial function

OBJECTIVE

We examined the associations among the circadian rhythms of blood pressure (BP), heart rate (HR) and left atrial function in essential hypertensive patients.

METHODS

The study included 237 essential hypertensive patients who completed 24-h ambulatory BP, HR monitoring and two-dimensional speckle tracking echocardiography (2DSTE). The strain and strain rate images were studied, and the following parameters were measured: left atrial reservoir strain and strain rate (LAS-S and LASR-S), left atrial conduit strain and strain rate (LAS-E and LASR-E), and left atrial booster strain and strain rate (LAS-A and LASR-A). The left atrial stiffness index (LASI) was identified as the ratio of E/e' to LAS-S. All participants were divided into three groups according to the percentage of nocturnal BP dipping (dippers, nondippers and reverse dippers).

RESULTS

The LASI was significantly higher in BP reverse dippers than in dippers and nondippers. LAS-S, LAS-E and LASR-E were significantly lower in BP reverse dippers than dippers and nondippers. Multivariate logistic regression analysis demonstrated that age, night-time mean SBP and the percentage of nocturnal HR decline were independently related to an increased LASI.

CONCLUSION

Impairment of the left atrial reservoir and conduit functions was correlated with abnormal BP and HR circadian rhythms in hypertension. Increased left atrial stiffness was associated with night-time SBP and the percentage of nocturnal HR decline.

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

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

Recent status of self-measured home blood pressure in the Japanese general population: a modern database on self-measured home blood pressure (MDAS)

Despite the clinical usefulness of self-measured home blood pressure (BP), reports on the characteristics of home BP have not been sufficient and have varied due to the measurement conditions in each study. We constructed a database on self-measured home BP, which included five Japanese general populations as subdivided aggregate data that were clustered and meta-analyzed according to sex, age category, and antihypertensive drug treatment at baseline (treated and untreated). The self-measured home BPs were collected after a few minutes of rest in a sitting position: (1) the morning home BP was measured within 1 h of waking, after urination, before breakfast, and before taking antihypertensive medication (if any); and (2) the evening home BP was measured just before going to bed. The pulse rate was simultaneously measured. Eligible data from 2000 onward were obtained. The morning BP was significantly higher in treated participants than in untreated people of the same age category, and the BP difference was more marked in women. Among untreated residents, home systolic/diastolic BPs measured in the morning were higher than those measured in the evening; the differences were 5.7/5.0 mmHg in women (ranges across the cohorts, 5.3-6.8/4.7-5.4 mmHg) and 7.3/7.7 mmHg in men (ranges, 6.4-8.5/7.0-8.7 mmHg). In contrast, the home pulse rate in women and men was 2.4 (range, 1.5-3.7) and 5.6 (range, 4.6-6.6) beats per minute, respectively, higher in the evening than in the morning. We demonstrated the current status of home BP and home pulse rate in relation to sex, age, and antihypertensive treatment status in the Japanese general population. The approach by which fine-clustered aggregate statistics were collected and integrated could address practical issues raised in epidemiological research settings.

Nighttime blood pressure decline as a predictor of renal injury in patients with hypertension: a population-based cohort study

We explored whether the nighttime blood pressure (BP) decline predicts renal function decline in a population-based cohort with primary hypertension. We measured the baseline ambulatory BP and glomerular filtration rate (GFR) in a cohort of 1,042 primary hypertensive patients. We repeated the GFR measurements and calculated the rate of GFR decline after a median follow-up of 5.8 years. The estimated GFR (eGFR) declined by -0.23 to -0.20 mL/min per year as the nighttime systolic BP (SBP), diastolic BP (DBP), and mean BP decline rates increased by 1% (P < 0.001). In the fully adjusted model, the nighttime SBP, DBP, and mean BP were all related to a steeper rate of eGFR decline by -0.25 to -0.22 mL/min per 1% increase. The adjusted multivariable results indicated that the odds of an eGFR decline were reduced by 46% when the nighttime SBP decline rate increased by 1% (OR= 0.54, 95% CI: 0.46-0.62). The restricted cubic spline model indicated a non-linear dose-response relationship with the nighttime SBP, DBP, and mean BP. Nighttime BP may be an important biomarker of renal function injury in hypertensive patients.

Nocturnal blood pressure decrease in patients with chronic kidney disease and in healthy controls - significance of obstructive sleep apnea and renal function

Background

Chronic kidney disease (CKD) is often associated with a blunted nocturnal BP decrease and OSA. However, it is not fully clear whether a relationship exists between reduction in renal function and obstructive sleep apnea (OSA) on the one hand and relative nocturnal BP decrease in CKD patients on the other. The aim of this study was to investigate the association between nocturnal BP decrease and renal function, the degree of OSA, vasoactive hormones, and renal sodium handling in CKD3-4 patients and healthy age-matched controls.

Methods

We performed brachial and central 24-hour ambulatory BP measurement and CRM in 70 CKD3-4 patients and 56 controls. In plasma, we measured renin, AngII, aldosterone, and vasopressin. In urine, 24-hour excretion of sodium, protein fractions from the epithelial sodium channel (u-ENaCγ), and the AQP2 water channels (u-AQP2) were measured.

Results

CKD patients had lower relative nocturnal BP decrease than controls: brachial (10% vs 17%, P=0.001) and central (6% vs 10%, P=0.001). Moderate-to-severe OSA was more frequent in patients (15 vs 1%, P<0.0001). Neither the presence of OSA nor eGFR were predictors of either brachial or central nocturnal BP decrease. CKD3-4 nondippers were more obese, had higher HbA1c level, and more often a history of acute myocardial infarction than CKD3-4 dippers (P<0.05).

Conclusion

CKD3-4 patients had lower brachial and central nocturnal BP decrease than healthy controls. OSA and eGFR were not associated with nondipping in CKD patients or healthy controls. Nondipping in CKD3-4 was associated with obesity, diabetes, and cardiovascular disease.

ClinicalTrials.gov ID

NCT01951196.

Nocturnal hypertension and right heart remodeling

BACKGROUND

We sought to investigate right ventricular (RV) and right atrial mechanics in patients with daytime, night-time and daytime-night-time hypertension.

METHODS

This cross-sectional study included 256 untreated patients who underwent 24-h ambulatory blood pressure monitoring and complete echocardiographic examination including strain analysis. Night-time hypertension was defined as nocturnal SBP at least 120 mmHg and/or DBP at least 70 mmHg and daytime hypertension as SBP at least 135 mmHg and/or DBP at least 85 mmHg.

RESULTS

RV structure, diastolic function and global longitudinal RV strain in patients with nocturnal hypertension are intermediate between daytime and daytime-night-time hypertension. On the other side, RV systolic and diastolic strain rates referring to the RV free wall are significantly deteriorated in the patients with nocturnal and daytime-night-time hypertension in comparison with normotension and daytime hypertension. Right atrial conduit function is significantly reduced in the patients with nocturnal and day-night-time hypertension comparing with other two groups, whereas right atrial reservoir and pump functions are intermediate between daytime and daytime-night-time hypertension. A 24-h SBP is independently of other clinical and echocardiographic parameters associated with RV and right atrial global strain.

CONCLUSION

RV mechanics is worse in night-time and daytime-night-time hypertensive patients than in normotensive controls and isolated daytime hypertensive patients. A 24-h SBP is independently associated with right heart mechanics.

Nocturnal diastolic blood pressure decline is associated with higher 25-hydroxyvitamin D level and standing plasma renin activity in a hypertensive population

Patients with nondipper hypertension are known to carry a high risk of cardiovascular complications. Vitamin D deficiency is associated with hypertension. Because vitamin D deficiency activates the renin-angiotensin-aldosterone system (RAAS), we hypothesized that this vitamin would interact with the RAAS to influence blood pressure (BP) in nondipper hypertensive patients. We performed a cross-sectional analysis of 1,007 outpatients with hypertension (HTN). Dipper and nondipper patterns were detected, and the two groups were matched for clinical, laboratory, 25-hydroxyvitamin D (25OHD) levels, and ambulatory blood pressure recording. Plasma renin activity (PRA), angiotensin II, and plasma aldosterone concentration (PAC) were assessed in 174 patients treated with calcium channel blockers or no medication. The mean 25OHD concentration in the entire study population was 12.3ng/dL, and the prevalence of vitamin D deficiency was 87.0%. Dipper and nondipper HTN were noted in 187 patients (24.6%) and 573 patients (75.4%). 25OHD levels were similar between nondipper and dipper HTN groups. Forward stepwise logistic regression analysis showed that BMI and age were independent predictors of nondipper HTN. Neither 25OHD levels nor RAAS components were included in the model. In correlation analyses, nocturnal decline of diastolic BP was positively associated with 25OHD levels and standing PRA (r = 0.152 p = 0.045, r = 0.165 p = 0.038, respectively). The present study showed that vitamin D deficiency was astonishingly prevalent in hypertensive subjects residing in Xinjiang, China. There may be a weakly association of nocturnal DBP decline with 25OHD levels and standing PRA levels. We found no association between vitamin D deficiency and nondipper HTN.

The relationship between nighttime hypertension and left atrial function

The authors sought to investigate the association between different hypertensive phenotypes and left atrial (LA) function assessed by the volumetric method and the strain method in patients with untreated hypertension. This cross-sectional study involved 236 untreated patients who underwent 24-hour ambulatory blood pressure monitoring and two-dimensional echocardiographic examination. Our findings showed that LA function gradually deteriorated from patients with normotension, across patients with daytime hypertension, to patients with night- and day-nighttime hypertension. LA reservoir and conduit functions were particularly deteriorated in patients with nighttime and day-nighttime hypertension compared with patients with normotension and patients with daytime hypertension, whereas LA pump function was compensatorily increased only in the participants with day-nighttime hypertension. Only nighttime hypertension and day-nighttime hypertension were independently associated with the reduced reservoir and conduit LA function. The difference between patients with daytime and nighttime hypertension was found in reservoir and conduit LA but not LA pump function.