Nocturnal Blood Pressure Variability Research Articles

Nocturnal blood pressure surge in seconds is associated with arterial stiffness independently of conventional nocturnal blood pressure variability in suspected obstructive sleep apnea patients.

Nocturnal blood pressure (BP) surge in seconds (sec-surge), which is characterized as acute transient BP elevation over several tens of seconds is induced by obstructive sleep apnea (OSA) and OSA-related sympathetic hyperactivity. The authors assessed the relationship between sec-surge and arterial stiffness in 34 nocturnal hypertensive patients with suspected OSA (mean age 63.9±12.6years, 32.4% female). During the night, they had beat-by-beat (BbB) BP and cuff-oscillometric BP measurements, and brachial-ankle pulse wave velocity (baPWV) was assessed as an arterial stiffness index. Multiple linear regression analysis revealed that the upward duration (UD) of sec-surge was significantly associated with baPWV independently of nocturnal oscillometric systolic BP variability (β=.365, p=.046). This study suggests that the UD of sec-surge, which can only be measured using a BbB BP monitoring device, may be worth monitoring in addition to nocturnal BP level.

Nocturnal hypoxemia, blood pressure, vascular status and chronic mountain sickness in the highest city in the world

Introduction Chronic mountain sickness (CMS) is a condition characterized by excessive erythrocytosis in response to chronic hypobaric hypoxia. CMS frequently triggers cardiorespiratory diseases such as pulmonary hypertension and right or left heart failure. Ambient hypoxia might be further amplified night-time by intermittent hypoxia related to sleep-disordered breathing (SDB) so that sleep disturbance may be an important feature of CMS. Our aim was to characterize in a cross-sectional study nocturnal hypoxaemia, SDB, blood pressure (BP), arterial stiffness and carotid intima-media thickness (CIMT) in highlanders living at extreme altitude. Methods Men aged 18 to 55 years were prospectively recruited. Home sleep apnoea test, questionnaires (short-form health survey; Montreal cognitive assessment; Pittsburgh Sleep Questionnaire Index and the Insomnia severity index), 24-h ambulatory BP monitoring, CIMT and arterial stiffness were evaluated in 3 groups: i) Andean lowlanders (sea-level); ii) highlanders living at 3,800 m and iii) highlanders living at 5,100 m. Analyses were conducted in sub-groups according to 1) CMS severity 2) healthy subjects living at the three different altitude. Results Ninety-two males were evaluated at their living altitudes. Among the 54 highlanders living at 5,100 m, subjects with CMS showed lower mean nocturnal oxygen saturation (SpO2), SpO2 nadir, lower pulse wave velocity and higher nocturnal BP variability than those with no-CMS. Lower nocturnal SpO2 nadir was associated with higher CMS severity (ß= −0.14, p=.009). Among the 55 healthy subjects, healthy highlanders at 5,100 m were characterized by lower scores on quality of life and sleep quality scales and lower mean SpO2 compared to lowlanders. Conclusions Lower nocturnal SpO2 and higher nocturnal BP variability are associated with CMS severity in individuals living permanently at high altitude. The role of lower SpO2 and higher nocturnal BP variability in the cardiovascular progression of CMS and in the overall prognosis of the disease need to be evaluated in further studies.

Very short-term beat-by-beat blood pressure variability in the supine position at rest correlates well with the nocturnal blood pressure variability assessed by ambulatory blood pressure monitoring.

Blood pressure variability (BPV) is an important indicator in risk stratification for hypertension. Among the daily BPVs assessed using a 24-h ambulatory blood pressure (BP) monitor nocturnal systolic BPV has been suggested to predict cardiovascular risks. We hypothesized that very short-term BPV at rest would correlate with nocturnal BPV because of the shared autonomic BP regulatory system under no daily exertion. Thirty untreated normotensive and hypertensive adults underwent 30-min continuous beat-by-beat BP recordings in the supine position, followed by 24-h ambulatory blood pressure monitoring (ABPM). The relationship between very short-term BPV (standard deviation (SD), coefficient of variation (CV)) and daytime and nocturnal BPV (SD, CV, average real variability (ARV), and standardized ARV (CV-ARV)) was assessed with Pearson's correlation coefficients. Very short-term BPV correlated significantly with nocturnal BPV (ARV, r = 0.604, p < 0.001) but not with daytime BPV. These trends were more pronounced with the increasing data length of continuous beat-by-beat BP recording. Using a data segment from the last 10 min of a 30-min continuous beat-by-beat BP recording resulted in a stronger correlation between very short-term BPV and nocturnal BPV than using earlier segments. The findings of this study suggest that very short-term BPV in the supine position at rest may predict nocturnal BPV. Since the burden of ABPM for patients has hindered clinical dissemination, very short-term BPV has the potential to develop a novel index of BPV.

Blood pressure lability is associated with subcortical atrophy in early Parkinson's disease.

Increased cerebral white matter intensities associated with blood pressure (BP) lability were reported in patients with Parkinson's disease. However, this type of cardiovascular dysautonomia has seldom been associated with disruptions in deep gray matter structures in Parkinson's disease. In the present study, the associations between BP lability and subcortical deep gray matter structures in early Parkinson's disease were evaluated. The present study included 98 early nondemented Parkinson's disease patients. Supine and orthostatic BPs were measured using head-up tilt tests. BP variabilities, measured as standard deviations of 24-h daytime and nighttime BPs, were assessed using 24-h ambulatory BP monitoring. Every patient underwent brain MRI and measurement of deep gray matter volumes. The associations between BP lability and deep gray matter structures were analyzed. Parkinson's disease patients with orthostatic hypotension had smaller volumes of striatum, particularly caudate, than patients without OH after adjusting for covariates of age, sex, disease duration, and Mini-Mental Status Examination score. Nocturnal BP variability was inversely associated with thalamus, hippocampus, and globus pallidus volumes. The results from the present study showed that BP lability was adversely associated with structural changes in early Parkinson's disease. Different forms of BP fluctuations influenced distinct deep gray matter structures.

The Adaptive Value and Clinical Significance of Allostatic Blood Pressure Variation.

In recent years, there has been interest in evaluating the morbidity and mortality risk of circadian, diurnal, or noctur-nal blood pressure variation. Variation is a normative property of blood pressure, necessary for survival. Like many physio-logical functions, blood pressure undergoes allostasis, meaning that the body does not defend a particular blood pressure value, but rather blood pressure maintains bodi-ly stability through continual change that is initiated by constantly fluctuating internal and external environmental stimuli. Be-cause of its allostatic and adaptive properties, the blood pressure response to unusual situations like a visit to the clinic can lead to misdiagnosis of hypertension. However, blood pressure variation is mostly ignored when evaluating hypertension, which is an arbitrary dichotomy. Whether variation is indicative of pathology should be determined by assessing its appro-priateness for the circumstance, which requires quantification of the sources and extent of normative blood pressure respons-es to everyday living. These responses will vary among populations due to evolutionary genetic differences. The incon-sistency of reports regarding aspects of ambulatory blood pressure variation as cardiovascular risk factors likely results from the fact that the measures used do not reflect the actual nature of blood pressure allostasis.

Severity of obstructive sleep apnea is associated with the nocturnal fluctuation of pulse rate, but not with that of blood pressure, in older hypertensive patients receiving calcium channel blockers.

Obstructive sleep apnea (OSA) is associated with increased variability in nocturnal blood pressure (BP). Calcium channel blockers (CCB) are superior to other classes of antihypertensives in decreasing BP variability. We investigated whether OSA severity is associated with nocturnal BP variability in older hypertensive patients treated with CCB. We measured home systolic and diastolic BP and pulse rate (PR) automatically during sleep at an interval of an hour once a week using an electronic sphygmomanometer in 29 hypertensive patients (aged ≥65 years) receiving CCB. We calculated the coefficient of variation (CV) from four consecutive measurements. All patients underwent a home-based portable sleep study. We found no difference in PR, BP or CV of BP between the patients with no-to-mild OSA and with moderate-to-severe OSA, categorized by the respiratory disturbance index (RDI) and 3% oxygen desaturation index (ODI). The CV of PR in patients with moderate-to-severe OSA was higher than the patients with no-to-mild OSA categorized by 3% ODI (P = 0.01). Body mass index was correlated with RDI and 3% ODI (r = 0.56 and 0.43, respectively). The CV of BP did not correlate to RDI or 3% ODI. The CV of PR was positively correlated both with RDI and with 3% ODI (r = 0.41 and 0.42, respectively). The severity of OSA was associated with PR variability, but not with BP variability, in older patients receiving CCB. Our results suggest the need for future studies to determine whether CCB can suppress the influence of OSA on BP fluctuation during sleep. Geriatr Gerontol Int 2019; 19: 604-610.

Continuous non-invasive determination of nocturnal blood pressure variation using photoplethysmographic pulse wave signals: comparison of pulse propagation time, pulse transit time and RR-interval

Objective: Cardiovascular diseases are the leading cause of death, whereas nocturnal ambulatory blood pressure (BP) is the most potent predictor for cardiovascular risk. The volume clamp and pulse transit time (PTT) are common methods for continuous non-invasive BP measurement, but have drawbacks during unsupervised ambulatory use and undisturbed sleep. The pulse propagation time (PPT), defined as the time between pulse wave systolic peak and diastolic peak, provides valid information about the pressure pulse waveform. However, the use of PPT for nocturnal BP variation determination and whether such variation is affected by BP or heart rate (i.e. RR-interval or RRI) has not been investigated. Approach: To assess whether the PPT method is suitable for ubiquitous nocturnal BP monitoring, we compared systolic blood pressure (SBP) estimates derived from PPT, PTT, and RRI signals with parallel recorded BP measurements. The RRI-derived SBP signals were used as a baseline for testing a potential heart rate dependency. This work provides an overview of BP measurements, presents the developed real-time signal analysis, and describes the performance assessment. The signal analysis was validated with data records from 42 subjects acquired from an ergometry and sleep laboratory in equal parts. Main results: The algorithms applied to the ergometry laboratory database achieved a correlation coefficient between reference SBP and estimated SBPPPT of 0.89 (p < 0.001) with bias 0.1 mmHg and limits of agreement (LoA) −29.8 to 30.0 mmHg, SBPPTT of 0.97 (p < 0.001) with bias 0.0 mmHg and LoA −15.2 to 15.3 mmHg, and SBPRRI of 0.96 (p < 0.001) with bias 0.0 mmHg and LoA −19.5 to 19.5 mmHg. For the sleep laboratory database, the correlation coefficient was 0.95 (p < 0.001) with bias 0.2 mmHg and LoA −18.3 to 18.8 mmHg for SBPPPT, 0.88 (p < 0.001) with bias 0.0 mmHg and LoA −25.0 to 24.9 mmHg for SBPPTT, and 0.88 (p < 0.001) with bias of 0.1 mmHg and LoA −23.6 to 23.7 mmHg for SBPRRI. A heart rate dependency of PPT or PTT could not be found. The analysis of variance shows no significant differences between the reference SBP values and the estimated values for either the ergometry (F(3, 627) = 2.27, p = 0.08) or the sleep laboratory (F(3, 327) = 2.28, p = 0.08). Significance: In conclusion, the PPT method seems to be an interesting alternative for continuous determination of SBP during simplified cardiovascular monitoring and sleep screening compared to more expensive devices based on volume clamp or PTT methods.

A12854 Severity of obstructive sleep apnoea is not associated with nocturnal blood pressure fluctuation in elderly hypertensive patients receiving amlodipine

Objectives: Obstructive sleep apnoea (OSA) is associated with increased variability in nocturnal blood pressure (BP). Calcium channel blockers (CCBs) are superior to other classes of antihypertensives in decreasing BP variability. We investigated whether OSA severity is associated with nocturnal BP variability in elderly hypertensive patients treated with amlodipine. Methods: We measured systolic and diastolic BP and pulse rate (PR) automatically during sleep at an interval of an hour once a week using an electronic sphygmomanometer in twenty-three hypertensive patients (≥65 years) receiving amlodipine. We calculated the coefficient of variation (CV) in data from 4 consecutive measurements. All patients underwent a home-based portable sleep study. Results: There were no differences in the average and CV of BP and the average PR between patients without OSA or with mild OSA and those with moderate to severe OSA as categorized by the respiratory disturbance index (RDI) and 3% oxygen desaturation index (ODI). The CV of PR in patients with moderate to severe OSA was lower than those of patients without OSA or with mild OSA categorized by 3% ODI. BMI was correlated with RDI and 3% ODI (r = 0.58 and 0.50, respectively). RDI and 3% ODI were not correlated with the CV of BP. The CV of PR was positively correlated with both RDI and 3% ODI (r = 0.42 and 0.45, respectively). Conclusion: The severity of OSA was associated with PR variability but not BP variability in older patients receiving CCB. Our results suggest the need for future studies to determine whether CCBs can suppress the influence of OSA on BP fluctuation during sleep.

A7026 Serum Lipopolysaccaride Binding Protein Is in Potential Association with Advanced Nocturnal Blood Pressure Variability in Middle-aged Hypertensive Men

A7026 Serum Lipopolysaccaride Binding Protein Is in Potential Association with Advanced Nocturnal Blood Pressure Variability in Middle-aged Hypertensive Men

Abstract P317: Nocturnal Blood Pressure Variability is associated with hs-CRP in Hypertensive Patients

Background: 24-hr Blood pressure (BP) variability and high sensitivity C-reactive protein (hs-CRP) have been found to be independently associated with increased cardiovascular diseases (CVD). Studies have shown a positive association between hs-CRP and BP variability in hypertensive population. In particular, nocturnal BP variability is associated with increased risk for CVD. However, the relationship between inflammation and nocturnal BP variability has not been examined in hypertensive patients. Methods: In this prospective study, 237 hypertensive patients were recruited from University of Alabama at Birmingham Hypertension clinic. As part of the study protocol, hs-CRP and 24-hr ambulatory blood pressure monitoring (ABPM) was performed at same visit. Patients with chronic kidney disease and those who did not have complete ABPM and hs-CRP values were excluded. Nocturnal BP variability was assessed using standard deviation. Results: Out of 202 patients who were included, 49.0% were women and 55.9% were African American. The mean age was 58.2 ± 10.9 years, mean nighttime BP (Systolic BP 132.4 ± 22.9 mmHg and diastolic BP 71.9 ± 14.0 mmHg), mean nighttime BP variability (systolic BP 13.4 ± 5.3 and diastolic BP 9.9 ± 4.2) and mean hs-CRP was 5.9 ± 7.0 mg/L. Regression analysis showed significant positive association (p-value = 0.033) between nocturnal BP variability and hs-CRP. Conclusion: In this study, we demonstrated that hs-CRP is strongly correlated with nocturnal BP variability in hypertensive patients, suggesting a likely mechanistic role of inflammation in the pathogenesis of nocturnal BP variability and a possible additive role in adverse cardiovascular outcomes.

Association between day-by-day and ambulatory blood pressure variability in type 2 diabetes patients

It remains unclear whether ambulatory blood pressure variability (BPV) contributes toward day-by-day BPV, despite the fact that not only day-by-day but also ambulatory BPV is reported to be a risk factor for type 2 diabetes patients. This study aimed to determine the association between day-by-day BPV and ambulatory BPV, which is especially distinguished between diurnal and nocturnal BPV, in type 2 diabetes patients. Day-by-day and ambulatory BPV were assessed in 30 type 2 diabetes patients (aged 54±15 years; 87% men; glycated hemoglobin: 9.1±1.9%) in inpatient settings. Day-by-day systolic BPV was correlated significantly with diurnal systolic BPV (r=0.426, P=0.019), but not nocturnal systolic BPV (r=0.175, P=0.354). Multiple regression analysis showed that diurnal systolic BPV and diurnal mean systolic blood pressure were associated independently with day-by-day systolic BPV. With respect to type 2 diabetes, these findings suggest that day-by-day BPV is reflected in diurnal BPV rather than nocturnal BPV.

Association between nocturnal blood pressure variation and wake-up ischemic stroke

Ischemic stroke during nocturnal sleep, known as wake-up stroke (WUS), has been reported to have more severe symptoms and worse outcomes than non-WUS. However, studies on risk factors for WUS are scarce and the association between nocturnal blood pressure (BP) and WUS is unclear. In this study, we used ambulatory blood pressure monitoring (ABPM) to examine the association between WUS and variation in nocturnal BP. A total of 369 patients with ischemic stroke within one week were consecutively enrolled. ABPM was applied 1–2weeks after the ictus because of possible reactive increments of BP; antihypertensive medications were delayed until ABPM. Patients were classified into two groups: WUS and non-WUS. Clinical characteristics, including ABPM parameters, were compared. Sixty-seven (18%) patients had WUS. In univariate analysis, patients with WUS had more severe stroke symptoms than patients with non-WUS. There were no differences in clinical characteristics. In addition, ABPM parameters, including nocturnal BP dipping and morning BP surge, were not associated with occurrence of WUS. Patients with WUS had more severe stroke symptoms and worse outcomes than those with non-WUS. Variation in nocturnal BP may not associated with the occurrence of WUS.

Increased nocturnal blood pressure variability is associated with renal arteriolar hyalinosis in normotensive patients with IgA nephropathy

Abnormal blood pressure (BP) variability (BPV), occurring as beat-to-beat, 24 h, and day-to-day fluctuations, is related to target organ damage. However, the associations between abnormal BPV and renal structural changes have not been clearly investigated. We evaluated the day time and night time BP s.d. and average real variability (ARV), which reflected short-term BPV, the night time to day time (N/D) ratio of systolic BP (SBP), and the 7-day BPV, in 29 normotensive IgA nephropathy (IgAN) patients. We further compared the results with renal structural changes. The degree of arteriosclerosis was positively correlated with age, s.d. of night time SBP and the N/D ratio of SBP, and was negatively correlated with the estimated glomerular filtration rate (eGFR). The degree of arteriolar hyalinosis was positively correlated with age, night time SBP, s.d. of day time and night time SBP, day time and night time ARV, the N/D ratio of SBP and 7-day SBP, and was negatively correlated with the eGFR. A multiple linear regression analysis revealed that the level of arteriolar hyalinosis, but not arteriosclerosis, was associated with the s.d. of night time SBP (β=0.63, P<0.01) or night time ARV (β=0.61, P<0.01) after adjustment for age, sex, body mass index, the eGFR and night time SBP. Multiple linear regression analyses indicated no significant correlation between the degree of arteriolar hyalinosis and the N/D ratio of SBP or 7-day SBP s.d. or between the degree of arteriosclerosis and any of the BPV parameters. In conclusion, short-term night time BPV was found to be associated with arteriolar hyalinosis in normotensive IgAN patients.

Wake-Up Stroke Is Associated With Greater Nocturnal Mean Arterial Pressure Variability

Wake-up strokes (WUS) account for ≈20% to 30% of ischemic strokes. Studies have shown that increased autonomic instability as measured by blood pressure variability (BPV) is greater in stroke patients than nonstroke patients, but no studies have compared BPV in WUS versus non-WUS patients. From a single-center prospective registry, we identified consecutive ischemic stroke patients. BPV was calculated as the coefficient of variation of the mean arterial pressure during the first 24 hours after hospitalization. We assessed 24-hour BPV as a continuous measure and in quartiles in WUS versus non-WUS patients using univariable and multivariable statistics. Among 369 patients (64.9±16.5 years; 50.1% male; 64.7% white), 78 were WUS (21.1%). Clinical characteristics and medical history were not different between WUS and non-WUS patients except WUS patients were older (69.0 versus 63.8 years; P=0.015) and more frequently had previous ischemic stroke (29.5% versus 17.2%; P=0.012). Initial 24-hour BPV (11.77 versus 10.76; P=0.098) was similar between groups. However, WUS patients had greater nocturnal BPV (10.50 versus 8.95; P=0.030), whereas daytime BPV was similar between groups (10.96 versus 10.47, P=0.459). In multivariate analysis, the highest quartile (≥11.48 mm Hg) of nocturnal BPV was independently associated with WUS (adjusted odds ratio, 1.95; confidence interval, 1.13-3.39; P=0.017). In this single-center study, we observed that greater nocturnal BPV during the first 24 hours after hospitalization occurred in WUS than non-WUS patients. Nocturnal autonomic instability warrants further study as a potential mechanism of WUS.

In Patients with Chronic Kidney Disease Short Term Blood Pressure Variability is Associated with the Presence and Severity of Sleep Disorders

Background/Aims: In chronic kidney disease (CKD) patients blood pressure variability (BPV) is associated with poor outcome. Sleep disturbances alter BP profiles in hypertensives but their influence on BPV in CKD patients is unknown. We screened a cohort of CKD/ESRD patients to investigate whether sleep quality impacts on BPV. Methods: Consecutive CKD patients’ sleep quality was assessed using validated questionnaires (Epworth Sleepiness Scale-ESS); International Restless legs scale-IRLS; Functional Outcomes of Sleep Questionnaire-FOSQ: Insomnia Severity Index-ISI; STOP-Bang). All patients underwent ambulatory blood pressure measurement. Results: 104 out of 143 enrolled patients (78.32% stage-3 CKD; 10.49% Stage-4; 11.19% Stage-5; 6.99% ESRD-under dialysis) completed all the questionnaires. 95.8% were hypertensives, 70% were non-dippers and 27.8% had resistant hypertension. STOP-Bang>4 proved sleep disorders in 84.84% of patients. Patients with IRLS>10 had greater diastolic nocturnal standard deviation (DNSD) and a trend (p=0.05) for systolic nocturnal SD (SNSD). Patients with ISI>14 had greater SNSD and in 28.8% FOSQ showed severely impaired sleep quality. Their systolic nocturnal BPV was significantly greater. ISI was independently associated with SNSD. FOSQ and diastolic nocturnal BPV were negatively correlated at the bivariate analysis and FOSQ independently predicts systolic nocturnal BPV at multivariate regression analysis. Conclusions: In CKD patients impaired sleep quality increases BPV, might contribute to their disease progression and worsen prognosis. Searching for sleep problems in CKD patients could help planning their treatment of sleep problems contributing to CV risk reduction. Our data provide the rationale working hypothesis for the need of studies with larger number of patients aimed to demonstrate improved outcome of CKD progression and CV risk with the treatment also of sleep disorders.

Nocturnal Blood Pressure Variability in Patients with Obstructive Sleep Apnea Syndrome.

Obstructive sleep apnea (OSA) is a common respiratory disorder associated with hypertension and cardiovascular complications. Blood pressure variability may be a sign of risk of cardiovascular events. The aim of this study was to investigate the hypothesis that severe OSA syndrome is associated with increased blood pressure variability. Based on respiratory polygraphy, 58 patients were categorized into two groups: severe OSA with apnea/hypopnea index (AHI) greater than 29 episodes per hour (mean 52.2 ± 19.0/h) and mild-to-moderate OSA with AHI between 5 and 30 episodes per hour (mean 20.2 ± 7.8/h). A 24-h noninvasive blood pressure monitoring was performed. The standard deviation of mean blood pressure was used as the indicator of blood pressure variability. In patients with severe, compared with mild-to-moderate OSA, a higher mean nocturnal systolic blood pressure (133.2 ± 17.4mmHg vs. 117.7 ± 31.2mmHg, p < 0.05) and diastolic blood pressure (80.9 ± 13.1mmHg vs. 73.8 ± 9.2, p < 0.01), nocturnal systolic blood pressure variability (12.1 ± 6.0 vs. 7.6 ± 4.3, p < 0.01) and diastolic blood pressure variability (10.5 ± 6.1 vs. 7.3 ± 4.0 p < 0.05), nocturnal mean blood pressure variability (9.1 ± 4.9 mmHg vs. 6.8 ± 3.5 mmHg) were detected. The findings of the study point to increased nocturnal systolic and diastolic arterial blood pressure and blood pressure variability as risk factors of cardiovascular complications in patients with severe OSA.

6A.06

Abstract Obstructive sleep apnea (OSA) causes blood pressure (BP) surge while OSA episode occurs. It could lead to increase of not only nocturnal BP level but also nocturnal BP variability, both of which increase the cardiovascular risk. Therefore, the assessment of BP surge could be valuable for the risk stratification and predicting cardiovascular events. We recently developed a trigger sleep BP monitoring (TNP) method that initiates BP measurement when oxygen desaturation falls below a variable threshold, and demonstrated that it can detect BP surge during apnea episodes. In this study, we evaluated the reproducibility of nocturnal BP parameters measured by TNP. 149 outpatients in whom polysomnography (PSG) was planned for the diagnosis of OSA (mean age 59.5 ± 13.7, 86.6% men) were subjected to TNP with PSG in the hospital for 2 consecutive days. In the same way as our previous study (J Clin Hypertens. 2014;16:459-466), we defined the hypoxia-peak SBP as the maximum SBP measured by an oxygen-triggered function, sleep SBP surge as the difference between hypoxia-peak SBP and the average of the SBPs measured by a fixed-interval function (30 min. intervals) within 30 minutes before and after the hypoxia-peak SBP, mean sleep SBP as the average of the sleep BPs measured only by the fixed-interval function, and minimum (basal) sleep SBP as the lowest SBP among all the sleep BPs measured by both oxygen-triggered and fixed-interval functions. Reproducibility was evaluated using the Repeatability Coefficient (RC), and the Intraclass Correlation Coefficient (ICC) for agreement. Mean SBP and mean DBP measured by both fixed-interval function and oxygen-triggered function, and hypoxia-peak SBP measured by oxygen-triggered function corresponded well in each day (ICC ranged 0.69 - 0.88). On the other hand, the reproducibility of sleep SBP surge (ICC 0.33) and minimum (basal) sleep SBP (ICC 0.39) was low. In conclusion, in the TNP parameters, the reproducibility of the hypoxia-peak SBP was good and comparable to mean sleep SBP measured by ordinary fixed interval BP monitoring.(Figure is included in full-text article.).

Systolic and diastolic short-term blood pressure variability and its determinants in patients with controlled and uncontrolled hypertension: A retrospective cohort study

Absolute blood pressure (BP) values are not the only causes of adverse cardiovascular consequences. BP variability (BPV) has also been demonstrated to be a predictor of mortality for cardiovascular events; however, its determinants are still unknown. This study considers 426 subjects with ambulatory BP monitoring (ABPM) measuring 24-h, diurnal and nocturnal absolute BP values and their standard deviations of the mean, along with nocturnal fall, age, sex and current treatment. Patients were divided in two subgroups, controlled and uncontrolled BP, and BPV of patients with “true” and “false” resistant hypertension was also analyzed. Nocturnal and 24-h BPV were higher in the group with uncontrolled hypertension. Multiple regression analysis showed that absolute BP, age, nocturnal fall, but not sex predicted BPV. Patients with “true” resistant hypertension had greater BPV than “false” resistant hypertension patients. Absolute BP resulted as the main determinant of 24-h and nocturnal BPV but not daytime BPV. Also nocturnal BP fall and age resulted as predictors of BPV in treated and untreated patients. Patients with “true” resistant hypertension have a higher BPV, suggesting a higher sympathetic activation. Evidence is still limited regarding the importance of short-term BPV as a prognostic factor and assessment of BPV cannot yet represent a parameter for routine use in clinical practice. Future prospective trials are necessary to define which targets of BPV can be achieved with antihypertensive drugs and whether treatment-induced reduction in BPV is accompanied by a corresponding reduction in cardiovascular events.

The relationship between nocturnal blood pressure and hemorrhagic stroke in Chinese hypertensive patients.

To study the relationship between nocturnal blood pressure (BP) variation and spontaneous intracerebral hemorrhage (ICH) among Chinese hypertensive patients and its clinical significance, the authors retrospectively screened 371 patients with primary hypertension (189 patients with ICH, 182 patients without ICH) in Shanghai and analyzed their demographics, clinical information, nocturnal blood pressure variability and medication. Compared with the control group, the levels of blood glucose, triglycerides, and creatinine were significantly increased in the ICH group, along with a marked reduction in nocturnal BP drop (P<.05). Multivariate logistic regression indicated that blood glucose, creatinine, and nocturnal mean arterial pressure were risk factors for ICH, and the magnitude of nocturnal BP drop was negatively related to the risk for ICH. There was no significant difference in the prevalence of reverse dippers between the large hematoma volume group and the small hematoma volume group (χ(2) =2.529, P=.112), nor among the patients taking angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, or calcium channel blockers (χ(2) =1.981, P=.371). Reverse dipping is associated with the risk for ICH, suggesting that appropriate antihypertensive drug and chronotherapy might be effective to normalize the rhythm of abnormal circadian variation in hypertensive patients.

Nocturnal Blood Pressure Non-Dipping, Posttraumatic Stress Disorder, and Sleep Quality in Women

Women with posttraumatic stress disorder (PTSD) have poor sleep quality and increased risk of cardiovascular disease (CVD). Non-dipping of nocturnal blood pressure may be an explanatory factor for the relationship between sleep and CVD found in previous research. The current study was designed to determine if non-dipping nocturnal blood pressure was associated with trauma exposure, PTSD diagnosis, PTSD symptoms, and sleep quality in a sample of women. Participants completed 24 hours of ABPM and self-report questionnaires. Non-dipping was defined as less than 10% reduction in blood pressure during sleep. The frequency of non-dippers did not differ by diagnostic status (d = .15). However, non-dippers endorsed more traumatic event categories (d = .53), more PTSD hyperarousal symptoms (d = .53), poorer overall sleep quality (d = .59), more frequent use of sleep medication (d = .62), greater sleep-related daytime dysfunction (d = .58), and longer sleep onset latencies (d = .55) than dippers. Increased attention to nocturnal blood pressure variation may be needed to improve blood pressure control in trauma-exposed women.