Obstructive sleep apnea and non-dipper: epiphenomena or risks of Alzheimer's disease?: a review from the HOPE Asia Network

Obstructive sleep apnea (OSA) and associated nocturnal blood pressure (BP) surges is associated with non-dipper. On the other hand, the relationship between neurodegenerative diseases and non-dipper hypertension has been reported. To date, few studies have evaluated the relationships of nocturnal BP dipping patterns and OSA in relation to neurodegenerative diseases, particularly Alzheimer's disease (AD). This review examines the etiology of the association between OSA and the non-dipper pattern of hypertension and how both are involved in the development of AD. To set the stage for this review, we first focus on the pathophysiology of AD, which is interrelated with sleep apnea and non-dipper through dysregulation of central autonomic network.

Blunted circadian variation of blood pressure in individuals with neurofibromatosis type 1

BACKGROUND

Cardiovascular events such as myocardial infarction and stroke are life-threatening complications associated with Neurofibromatosis type 1 (NF1). As previous studies observed an association between cardiovascular events and the loss of circadian variations of blood pressure, we investigated the 24 h circadian rhythm of blood pressure (BP) in 24 NF1 patients (10 males and 14 females, with a mean age of 39.5 years ± 14 years) by using ambulatory blood pressure monitoring (ABPM).

RESULTS

Only one-third of the patient were dippers, 50% were non-dippers, and 17% were risers. Reduced variability of systolic and diastolic nocturnal blood pressure was observed in NF1 patients compared with several studies of normotensive individuals (p = 0.024). In NF1 patients, the blunted systolic nocturnal decline was significantly associated with the number of neurofibromas (p = 0.049) and the presence of a plexiform neurofibroma (p = 0.020).

CONCLUSIONS

Most NF1 patients in this study showed a "non-dipper" pattern with a blunted nocturnal BP decline, which is considered an independent risk factor for cardiovascular events in normotensive and hypertensive individuals. Periodic monitoring of BP should be included in NF1 follow-up guidelines to diagnose masked hypertension or a non-dipper/riser pattern which would significantly increase the morbidity and mortality of NF1 patients to implement therapeutic strategies.

Association between epicardial adipose tissue and blood pressure: A systematic review and meta-analysis

AIMS

Epicardial adipose tissue has been reported to be associated with the development of cardiometabolic disease. Whether this is true for hypertension and non-dipper blood pressure remains controversial. Here, we conducted a systemic review and meta-analysis to evaluate the association between EAT and blood pressure.

DATA SYNTHESIS

Pubmed, Embase, and Web of Science were searched for relevant papers. Studies reported on the difference of EAT thickness between hypertensive and normotensive patients, or those recorded odds ratio (OR) between EAT and hypertension were included. The standard mean difference (SMD) and ORs were extracted and pooled using a random-effects model respectively. We further assessed the effect of EAT on circadian rhythm of blood pressure by combining multiple-adjusted ORs for non-dipper blood pressure. Seven studies with an overall sample of 1089 patients reported the mean difference of EAT thickness between hypertensive and normotensive patients, and the hypertensive patients had higher EAT (SMD = 1.07; 95% CI: 0.66-1.48; I2 = 89.2%) compared with controls. However, the pooled association between EAT and hypertension from two studies was not significant (OR = 1.65, 95%CI 0.62-4.68; I2 = 87.5%). The summary risk effect of EAT on non-dipper blood pressure from six studies comprising1208 patients showed that each 1 mm increment of EAT was associated with a 2.55-fold risk of non-dipper blood pressure.

CONCLUSION

Hypertensive patients tend to present higher EAT thickness near the right ventricular wall and increased EAT thickness might be associated with high risk of non-dipper blood pressure. Future researches are warranted to determine the causal link between EAT and hypertension and the underlying mechanism.

The Association of Morning Surge and Night-Time Dipping Blood Pressure with Significant and Complex Coronary Artery Lesions

INTRODUCTION

Hypertension responsible for more than 10 million deaths annually worldwide and abnormal diurnal blood pressure (BP) variation is associated with cardiovascular events.

AIM

This study aimed to investigate the association between the 24-h ambulatory night BP dipping and morning BP surge (MS) with characteristic of coronary artery lesions that may contribute cardiovascular events and mortality burden.

METHODS

A cross sectional study over 1-year, collected 263 cases of hypertensive (80%) and non-hypertensive patients, aged 61 ± 10 years, who undergoing invasive coronary angiography (CAG) and 24-h ambulatory BP monitoring admitted to cardiology department complain of chest pain. The night-time/day-time dip and sleep-trough MS were calculated. Non-dipper status was considered when night-time/day-time dip < 10%, and significant coronary lesion (SCL) when ≥ 50 % stenosis in 1.5 mm vessels. The SYNTAX (Synergy Between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery) score was used to quantify the complexity of SCL.

RESULT

The mean morning systolic BP (SBP) surge was higher in the high SYNTAX Score subgroup than low and intermediate subgroups (25 ± 11 vs 17 ± 13 and 10 ± 10 mmHg, p < 0.010). Non-dipper SBP status was more frequently in patients with SCL than non-SCL (p < 0.019). In ordinal regression, hypertension was independent predictor of SCL (odd ratio: 0.40, p < 0.003), the night-time/day-time BP dip was independent predictor of being in a higher SYNTAX score subgroup (systolic odd ratio: 0.88, diastolic odd ratio: 1.14 p < 0.05).

CONCLUSION

Hypertension is associated with SCL and the night-time/day-time BP dip as a continuous variable is associated with complex coronary lesion. Non-dipping as categorical variable and morning BP surge were not independent predictors of significant or complex coronary lesions.

Nocturnal blood pressure changes in Parkinson's disease: correlation with autonomic dysfunction and vitamin D levels

Nocturnal blood pressure (BP) changes are an indicator of autonomic dysfunction. We aim to investigate the correlation between nocturnal blood pressure (BP) variability, vitamin D levels and Parkinson's disease severity (PD) in this study. Thirty-five patients with PD participated in the study. Disease severity was evaluated by United Parkinson's Disease Rating Scale (UPDRS) and Hoehn and Yahr Scale (HYS). Equivalent levodopa dose was calculated and 25-hydroxyvitamin D levels were measured. The Non-Motor Symptom Questionnaire (NMSQ) was applied to all patients. Ambulatory BP monitoring for 24 h was established. Patients were divided into three groups according to nocturnal BP results: dippers (normal finding-a decline in mean nighttime BP of more than 10%); non-dippers (pathological-a decline in mean nighttime BP of less than 10%); reverse dippers (pathological-an increase in mean nighttime BP) .The mean score of the NMSQ was higher in the group with HYS > 2 (p = 0.050). Four patients were dipper, 17 patients were non-dipper and 16 patients were reverse dipper. There was no significant difference between the three groups in terms of age, gender, disease duration, age of the disease onset, disease stage, disease duration, dopamine agonist usage, levodopa equivalent dose, vitamin D level and NMSQ scores. NMSQ scores are high in advanced PD. Ambulatory BP monitoring is useful in detecting autonomic dysfunction. The number of patients with non-dipping and reverse dipping is high in PD, independent from PD severity, drug dose, vitamin D and the other NMS symptoms.

Characterization of circadian blood pressure patterns using non-linear mixed effects modeling

Characterizing the time course of baseline or pre-drug blood pressure is important in acquiring unbiased estimates of antihypertensive drug effect. In this study, we recruited 23 healthy male volunteers and measured systolic (SBP) and diastolic blood pressure (DBP) over 24 hours on an hourly basis. Using a non-linear mixed effects model, circadian rhythm observed in blood pressure measurements was described by incorporating two cosine functions with periods 24 and 12 hours. A mixture model was applied to identify subgroups exhibiting qualitatively different circadian rhythms. Our results suggested that 78% of the study population, defined as ‘dippers’, demonstrated a typical circadian profile with a morning rise and a nocturnal dip. The remaining 22% of the subjects defined as ‘non-dippers’, however, were not adequately described using the typical profile and demonstrated an elevation of blood pressure during night-time. Covariate search identified weight as being positively correlated with mesor of SBP. Visual predictive checks using 1,000 simulated datasets were performed for model validation. Observations were in agreement with predicted values in ‘dippers’, but deviated slightly in ‘non-dippers’. Our work is expected to serve as a useful reference in assessing systematic intra-day blood pressure fluctuations and antihypertensive effects as well as assessing drug safety of incrementally modified drugs.

Epicardial Fat Thickness and Neutrophil to Lymphocyte Ratio are Increased in Non-Dipper Hypertensive Patients

Background

In this study, we aimed to investigate the relationship between echocardiographic epicardial fat thickness (EFT), neutrophil to lymphocyte ratio (NLR; an important inflammatory marker), and diurnal blood pressure (BP) changes in patients with recently diagnosed essential hypertension.

Methods

A total of 647 patients underwent echocardiography and 24 hours of ambulatory BP monitoring. EFT was measured by echocardiography, while NLR was measured by dividing the neutrophil count by the lymphocyte count. Patients were categorized into three groups according to BP pattern: the normotensive group, the dipper group, and the non-dipper group.

Results

The mean EFT was highest in the non-dipper group (non-dipper group, 7.3 ± 3.0 mm; dipper group, 6.1 ± 2.0 mm; control group, 5.6 ± 2.0 mm; p < 0.001). NLR was also highest in the non-dipper group (non-dipper, 2.75 ± 2.81; dipper, 2.01 ± 1.32; control, 1.92 ± 1.11; p < 0.001). EFT was significantly correlated with age (r = 0.160, p < 0.001) and NLR (r = 0.353, p < 0.001). Furthermore, an EFT ≥ 7.0 mm was associated with the non-dipper BP pattern with 51.3% sensitivity and 71.6% specificity [95% confidence interval (CI) = 0.56–0.65, p < 0.001]. In a multivariate analysis, EFT [adjusted odds ratio (OR) = 3.99, 95% CI = 1.22–13.10, p = 0.022] and NLR (OR = 1.34, 95% CI = 1.05–1.71, p = 0.018) were independent parameters that distinguished a non-dipper pattern after adjustment for cardiovascular risk factors.

Conclusion

EFT and NLR are independently associated with impaired diurnal BP profiles in hypertensive individuals. EFT (as measured by echocardiography) and NLR appear to be helpful in stratifying cardiometabolic risk.

White coat hypertension and obstructive sleep apnea

PURPOSE

This study aimed to determine blood pressure characteristics and long-term progress in patients with white coat hypertension (WCH) and obstructive sleep apnea (OSA).

METHODS

Systolic blood pressure (SBP) and diastolic blood pressure (DBP) and sleep test results over a period of 26 months were analyzed from WCH patients with OSA (n = 28), WCH patients (n = 23), and healthy control subjects (n = 27).

RESULTS

At the end of observation, WCH patients with OSA presented significantly increased daytime and nighttime BP and lower diurnal difference of SBP (all Ps < 0.05) and the increased rate of "non-dipper" status (SBP 28.6 %, DBP 32.1 %) was significantly higher when compared with WCH and control groups (all Ps < 0.01). Sustained hypertension was observed in 42.8 % of the WCH patients with OSA, which was significantly higher than that in the WCH and control groups (Ps < 0.01) and was predicted by non-dipper status via 24-h ambulatory SBP/DBP monitoring (Ps < 0.05).

CONCLUSION

WCH may represent a prehypertension status, which could develop into sustained hypertension with OSA.

Different chronotherapeutic effects of valsartan and olmesartan in non-dipper hypertensive patients during valsartan treatment at morning

This study was undertaken to evaluate the differences in chronotherapeutic effects of angiotensin-II receptor blockers, valsartan and olmesartan in hypertensive patients with non-dipper blood pressure (BP) pattern during valsartan at morning. Ninety four patients were enrolled, and 40 patients were judged to be non-dippers. In these patients, same dose of valsartan was changed to evening (Val-E, n = 12), or olmesartan (equivalent dose of valsartan) was given at morning (Olm-M, n = 13) or evening (Olm-E, n = 15) for 4 months. BP decreased during sleep and increased during waking hours in Val-E group. In Olm-M and Olm-E groups, BP decreased during sleep and waking hours. Percent reduction in BP at night-time compared to BP at waking hours significantly increased after changing the dose regimen in each group. Serum creatinine decreased and estimated glomerular filtration rate (eGFR) elevated in Olm-M and Olm-E, but not Val-E groups. Positive correlation between systolic BP (SBP) during sleep and serum creatinine, and negative correlation between SBP during sleep and eGFR were detected. These data suggest that dipper BP pattern could be obtained by chronotherapeutic approach using valsartan and olmesartan in non-dipper patients with valsartan at morning. Morning and evening olmesartan, but not evening valsartan improved renal function in these patients.

Simple renal cysts and circadian blood pressure: are they related to each other in patients with hypertension?

Previous studies have shown that the presence of simple renal cysts was related to hypertension. However, the relationship between simple renal cysts and circadian blood pressure was not studied before. Our study population comprised of newly diagnosed patients with essential hypertension. Medical history, physical examination and office blood pressure measurements, laboratory analysis, ambulatory blood pressure measurements, renal ultrasonography, and 24-h urine specimens were collected. In total, the study included 190 patients (male/female ratio 77/113; mean age 50.3 ± 11.3). Overall, 127 (66.8%) patients were dippers and 92 (48.4%) had at least one simple renal cyst. Thirty-five patients had solitary cysts and 57 patients had multiple cysts. Cysts were bilateral in 47 of patients. Most of ambulatory blood pressure recordings were higher in patients with at least one simple cyst when compared to patients without cysts. In multivariate logistic regression analysis, serum uric acid (P: 0.047, OR: 1.287, CI: 1.011-1.658), lower creatinine clearance (P: 0.001, OR: 1.030, CI: 1.012-1.049), presence of diabetes (P: 0.029, OR: 2.451, CI: 1.094-5.491), and presence of at least one cyst in each kidney (P: 0.002, OR: 3.087, CI: 1.533-6.212) were found to be independently related to nocturnal non-dipping. In conclusion, the presence of simple renal cysts is related to higher ambulatory BP and is associated with non-dipping phenomenon in patients with essential hypertension.