Magnitude of Morning Surge in Blood Pressure Is Associated with Sympathetic but Not Cardiac Baroreflex Sensitivity

Association of Night-to-Night Adherence of Continuous Positive Airway Pressure With Day-to-Day Morning Home Blood Pressure and Its Seasonal Variation in Obstructive Sleep Apnea

Background

The aim of this study was to investigate the association between night‐to‐night adherence to continuous positive airway pressure (CPAP) therapy and both home blood pressure (BP) level on the following day and seasonal variation in home BP in patients with obstructive sleep apnea.

Methods and Results

We analyzed 105 participants who had been diagnosed with obstructive sleep apnea (average apnea‐hypopnea index, 49.7±18.4 per hour) and who were already receiving CPAP therapy. Home BP (twice every morning and evening) and CPAP adherence data were automatically transmitted to a server for 1 year. A mixed‐effects model for repeated measures analysis was used to examine associations of night‐to‐night good CPAP adherence with day‐to‐day home BP within the same patient after adjusting for covariates. The average number of days in which patients achieved both CPAP adherence and morning or evening home BP measurement was 206.6±122.7 days (21 487 readings) and 191.2±126.3 days (20 170 readings), respectively. Good CPAP adherence (>4 hours per night of use) was achieved on the evening or morning before home BP measurements (86.8% and 86.9%, respectively). After adjustment for confounders, good CPAP adherence was negatively associated with morning home systolic BP (β, −0.663; P=0.004) and diastolic BP (β, −0.829; P<0.001). Morning home systolic BP in winter in the individuals with good CPAP adherence was significantly lower than that in individuals without such adherence (P<0.05). These associations were not found in evening home BP.

Conclusions

Good adherence to CPAP therapy was negatively associated with morning home BP on the following day in patients with obstructive sleep apnea. The association was remarkable in the winter season.

Differential Effect of the Morning Blood Pressure Surge on Prognoses Between Heart Failure With Reduced and Preserved Ejection Fractions

BACKGROUND

Rising blood pressure (BP) in the morning, known as the morning BP surge (MBPS), is known to pose a risk for cardiovascular events in hypertensive individuals. It was not known whether the MBPS was associated with a worse prognosis in patients with heart failure (HF) with a reduced (HFrEF) or preserved (HFpEF) ejection fraction.Methods and Results:We performed a prospective, observational cohort study of hospitalized HF patients who underwent ambulatory BP monitoring (ABPM). The MBPS was calculated by subtracting the mean systolic BP (SBP) during the 1 h that included the lowest sleep BP from the mean SBP during the 2 h after waking. The MBPS group was defined as the top decile of MBPS (>40 mmHg). In all, 456 hospitalized HF patients (mean [±SD] age 68±13 years, 63.9% male) were followed-up for a median of 1.67 years. There were 90 events (16.3 per 100 person-years) of the composite outcome (all-cause mortality and worsening HF) in the HFrEF group, compared with 53 events (19.6 per 100 person-years) in the HFpEF group. Multivariate Cox regression analysis showed that MBPS was a significant predictor of outcome (hazard ratio 2.84, 95% confidence interval 1.58-5.10, P<0.01) in the HFrEF but not HFpEF group.

CONCLUSIONS

MBPS was found to be a novel predictor of worsening HF in patients with HFrEF.

Aging and Vascular Compliance in Hypertensive Patients Mirrored in Routine Investigations

The global prevalence of arterial hypertension is increasing. Due to its consequences, hypertension is a leading cause of morbidity /mortality. In this regard, awareness of the importance of diagnosis as well as proper treatment of hypertension is mandatory.

OBJECTIVES

This study aims to analyze vascular compliance and different pressure characteristics depending on age, along with highlighting some clinical-paraclinical correlations in people diagnosed with hypertension. We used usual laboratory analyzes and the blood pressure values obtained using ABPM/24 hr, in addition to highlighting the impact of age on those parameters.

MATERIALS AND METHODS

The sample comprises of 99 adults diagnosed with hypertension. We divided them into 2 groups, according to age: cases sample: 52 patients (age> 60 years old) and control sample: 47 patients (age< 60 years old).

RESULTS

In the control group, RDW was correlated with the general and diurnal systolic and diastolic hypertonicity indexes and the platelet count was positively correlated only with the morning surge. The dipping profile correlates negatively with RDW. In the elderly, all three systolic blood pressure parameters are influenced by ESR and also correlate negatively with HDL, with an inverse proportional relationship. Statistically significant correlations were found between blood glucose and diurnal systolic and diastolic hypertonicity indexes. Mean Pulse Pressure correlates in the elderly with HDL (negative correlations) and in the young with RDW (positive correlations).

CONCLUSIONS

Vascular compliance can be estimated with the help of HDL in the elderly and RDW in young people, considering the influence of the two parameters on pulse pressure.

Salt intake impacts sympathetic neural control but not morning blood pressure surge in premenopausal women with a history of normal pregnancy

Salt intake may alter blood pressure (BP) regulation, but no study has investigated the impact of salt reduction versus salt loading on morning blood pressure surge (MBPS) and sympathetic neural control in premenopausal women with a history of normal pregnancy. Nine healthy women (42 ± 3 yr; mean ± SD) were given a low-salt diet (LS; 50 mEq sodium/day) and high-salt diet (HS; 250 mEq sodium/day) for 1 wk each (~2 mo apart with the order randomized), while water intake was ad libitum. Ambulatory BP at 24 h was measured, and the percent change in blood volume (BV) was calculated following LS and HS. MBPS was defined as the morning systolic BP (averaged for 2 h after wake-up) minus the lowest nocturnal systolic BP. Beat-by-beat BP, heart rate, and muscle sympathetic nerve activity (MSNA) were measured during supine rest. Signal averaging was used to characterize changes in beat-by-beat mean arterial pressure and total vascular conductance following spontaneous MSNA bursts to assess sympathetic vascular transduction. Ambulatory BP and MBPS (32 ± 7 vs. 26 ± 12 mmHg, P = 0.208) did not differ between LS and HS. From LS to HS, BV increased by 4.3 ± 3.7% (P = 0.008). MSNA (30 ± 20 vs. 18 ± 13 bursts/100 heartbeats, P = 0.005) was higher, whereas sympathetic vascular transduction was lower in LS than HS (both, P < 0.01). Changes in MSNA from LS to HS were correlated to percent changes in BV (r = -0.673; P = 0.047). Thus, salt intake affects sympathetic neural control but not MBPS in premenopausal women with a history of normal pregnancy. The underlying mechanisms remain unknown; however, alterations in sympathetic vascular transduction may, in part, contribute.NEW & NOTEWORTHY This is the first study to demonstrate that MBPS and ambulatory BP were not affected by salt intake despite a significant change in sympathetic outflow in healthy premenopausal women with a history of normal pregnancy. This may be due to compensatory adaptations in MSNA and sympathetic vascular transduction during salt reduction versus salt loading.

Automatic detection algorithm for establishing standard to identify "surge blood pressure"

Blood pressure (BP) variability is one of the important risk factors of cardiovascular disease (CVD). “Surge BP,” which represents short-term BP variability, is defined as pathological exaggerated BP increase capable of triggering cardiovascular events. Surge BP is effectively evaluated by our new BP monitoring device. To the best of our knowledge, we are the first to develop an algorithm for the automatic detection of surge BP from continuous “beat-by-beat” (BbB) BP measurements. It enables clinicians to save significant time identifying surge BP in big data from their patients’ continuous BbB BP measurements. A total of 94 subjects (74 males and 20 females) participated in our study to develop the surge BP detection algorithm, resulting in a total of 3272 surges collected from the study subjects. The surge BP detection algorithm is a simple classification model based on supervised learning which formulates shape of surge BP as detection rules. Surge BP identified with our algorithm was evaluated against surge BP manually labeled by experts with 5-fold cross validation. The recall and precision of the algorithm were 0.90 and 0.64, respectively. Processing time on each subject was 11.0 ± 4.7 s. Our algorithm is adequate for use in clinical practice and will be helpful in efforts to better understand this unique aspect of the onset of CVD.

Graphical abstract

Morning blood pressure surge is associated with autonomic neuropathy and peripheral vascular disease in patients with diabetes

Although vascular and autonomic nervous system have been involved in the regulation of morning surge in blood pressure (MBPS), data on clinical correlates of MBPS in diabetic population are scarce, in particular with regard to diabetic complications. This study was aimed at investigating predictors and correlates of MBPS in diabetes. In a cross-sectional study including 167 patients with diabetes (age 58.5 ± 11.1 years, duration 15.9 ± 12.1 years), clinical variables, diabetic and neuropathic complications, and MBPS (using 24-h ambulatory blood pressure monitoring) were measured. The upper quartile of MBPS (>30.5 mmHg) was associated with higher values of waist circumference (P = 0.027), triglycerides (P = 0.021), and Michigan Diabetic Neuropathy Score (P = 0.042), with lower HDL cholesterol (P = 0.030), and with the presence of cardiovascular autonomic neuropathy (CAN) (P = 0.016) and peripheral vascular disease (PVD) (P < 0.0001). In a logistic regression analysis, PVD (odds ratio: 10.2, P = 0.001), CAN (odds ratio: 6.09, P = 0.016), and diastolic blood pressure (BP) (odds ratio: 1.06, P = 0.022) predicted MBPS upper quartile (r² = 0.20, P = 0.0005). In a multiple regression analysis, PVD (P = 0.002) and diastolic BP (P = 0.003) were the only determinants of MBPS (r² = 0.20). MBPS upper quartile was associated with BP dipping (systolic BP day-night reduction > 10%) (P = 0.012), and MBPS was positively related to systolic (rho = 0.41, P < 0.0001) and diastolic BP day-night reduction. In conclusion, metabolic syndrome stigmata, diastolic BP, CAN and PVD are the main predictors of MBPS in the diabetic population. Excessive MBPS and nondipping are not concurrent 24-h BP alterations. Autonomic dysfunction might exert an exacerbating effect on MBPS phenomenon.

Blood Pressure Variability and Autonomic Dysfunction

PURPOSE OF REVIEW

This review considers the relationship between abnormal blood pressure (BP) variability and autonomic dysfunction through an attempt to answer questions about its clinical relevance and pertinence to diabetes and cardiovascular autonomic neuropathy (CAN) and which therapeutic measures can lessen its cardiovascular impact.

RECENT FINDINGS

Office, ambulatory, and home BP monitoring identify posture-related, circadian, short-term, and long-term BP variabilities. Abnormal BP variability is a risk marker for organ damage, mortality, and cardiovascular events. Moreover, BP variability changes are common in diabetes and associated with CAN and possibly exacerbated by comorbidities like nephropathy, obstructive sleep apnoea syndrome, and chronic pain. The prognostic role of nondipping and reverse dipping is well documented in diabetes. Some findings suggest the possibility of restoring dipping with the dosage time of antihypertensive agents. Diabetes is a favorable scenario for altered BP variability, which might mediate the harmful effects of CAN. Preliminary data suggest the protective effect of targeting BP variability. However, further longitudinal outcome studies are needed. In the meantime, BP variability measures and practical expedients in antihypertensive treatment should be implemented in diabetes.

Morning blood pressure surge: pathophysiology, clinical relevance and therapeutic aspects

Morning hours are the period of the day characterized by the highest incidence of major cardiovascular events including myocardial infarction, sudden death or stroke. They are also characterized by important neurohormonal changes, in particular, the activation of sympathetic nervous system which usually leads to a rapid increase in blood pressure (BP), known as morning blood pressure surge (MBPS). It was hypothesized that excessive MBPS may be causally involved in the pathogenesis of cardiovascular events occurring in the morning by inducing hemodynamic stress. A number of studies support an independent relationship of MBPS with organ damage, cerebrovascular complications and mortality, although some heterogeneity exists in the available evidence. This may be due to ethnic differences, methodological issues and the confounding relationship of MBPS with other features of 24-hour BP profile, such as nocturnal dipping or BP variability. Several studies are also available dealing with treatment effects on MBPS and indicating the importance of long-acting antihypertensive drugs in this regard. This paper provides an overview of pathophysiologic, methodological, prognostic and therapeutic aspects related to MBPS.

Morning surge in blood pressure and sympathetic activity in Mongolians and Han Chinese: a multimodality investigation of hypertension and dyssomnia

Background

Hypertension and dyssomnia are increasing significantly in Mongolians, and the related factors of ethnic differences in hypertension and dyssomnia between Mongolians and Han Chinese are unclear. This study examined the relationship of morning surge in blood pressure (MBP) with ethnicity, sleep situation, and sympathetic activity throughout the day.

Methods

Of 692 hypertensive patients screened, 202 subjects with dyssomnia were selected. They were then divided into Mongolian (n = 87) and Han (n = 115) groups. The differences in dyssomnia, 24-h blood pressure, and urinary catecholamine were analyzed in all subjects; they were then further divided according to the degree of dyssomnia (low, moderate, and severe) to determine the differences in blood pressure and catecholamine.

Results

Mongolians had a lower history of smoking, daytime dysfunction, nocturnal heart rates, and dopamine levels, but their body mass index, triglyceride, fasting glucose, morning surge in systolic blood pressure (MSBP), nocturnal systolic blood pressure (NSBP), nocturnal diastolic blood pressure, daytime systolic blood pressure, daytime heart rates, and dopamine level (D-DA) were higher than those of Han Chinese. With the aggravation of dyssomnia, MSBP, NSBP, D-NE, daytime epinephrine, and D-DA of Mongolians and Han Chinese increased gradually, but the rate of increase was faster in the latter (p < 0.05). D-DA was entered into the MSBP regression model of Mongolians (intercept, 157 mmHg), whereas D-DA and D-NE were entered into the MSBP regression model of Han Chinese (intercept, 142 mmHg).

Conclusion

Worsened dyssomnia induces higher MSBP and augments sympathetic excitability in Mongolians and Han Chinese. Mongolians with hypertension and dyssomnia had higher MSBP baseline and D-DA but lower N-DA. With an increase in D-DA, MSBP in Han and Mongolian patients increased gradually.