Obstructive sleep apnea syndrome as a cause of resistant hypertension

Sleep Apnea and Hypertension Control among Hispanic/Latino Adults in the United States: Results from the Hispanic Community Health Study / Study of Latinos (HCHS/SOL)

Objectives

Hispanic/Latino adults have a high prevalence of uncontrolled hypertension predisposing them to CVD. We hypothesize that sleep apnea severity is associated with uncontrolled blood pressure (BP) and resistant hypertension in Hispanic/Latino adults.

Methods

This was a cross-sectional study of 2,849 Hispanic Community Health Study/Study of Latinos participants with hypertension (i.e., systolic BP ≥130 mm Hg, or diastolic BP ≥80 mm Hg or self-reported antihypertensive medication use) who were taking at least one class of antihypertensive medication. Participants were categorized as having controlled (BP < 130/80 mmHg among those on hypertension treatment) , uncontrolled (BP ≥ 130/80 mmHg using one or two classes of antihypertensive medications), or resistant hypertension (BP ≥ 130/80 mmHg while on ≥ 3 classes of antihypertensive medications or the use of ≥ 4 classes of antihypertensive medications regardless of BP control). Sleep apnea was classified based on the respiratory event index (REI; events/h) as mild (REI ≥ 5 and < 15), moderate-to-severe (REI ≥ 15), or no sleep apnea (REI < 5).

Results

In multinomial logistic regression, moderate-to-severe sleep apnea (vs. no sleep apnea) was associated with higher odds of resistant hypertension (Odds Ratio [OR], 2.15; 95% CI, 1.36-3.39 at 4% desaturation and OR 1.68; 95% CI, 1.05-2.67 at 3% desaturation). Neither mild nor moderate-to-severe sleep apnea was associated with uncontrolled hypertension.

Conclusion

Among diverse Hispanic/Latino persons, moderate-to-severe but not mild sleep apnea was associated with resistant hypertension. Identification and management of sleep apnea in this population may improve BP control and subsequently prevent adverse cardiovascular outcomes.

Increasing obstructive sleep apnea risk is associated with albuminuria in Korean adults: cross-sectional analysis

Several studies have shown an association between albuminuria and obstructive sleep apnea (OSA). However, studies on the relationship between the STOP-BANG questionnaire that can screen for OSA and microalbuminuria are still insufficient. Therefore, this study attempted to clarify the relationship between microalbuminuria and OSA risk using the STOP-BANG questionnaire in Korean adults. A total of 7478 participants (3289 men and 4189 women) aged over 40 were enrolled in the Korean National Health and Nutrition Examination Survey from 2019 to 2020. STOP-BANG questionnaire to screen OSA was obtained from subjects. The urinary albumin/creatinine ratio (ACR) and proteinuria were measured via a single dipstick to evaluate renal function. The high OSA risk group had a higher mean ACR value than the low OSA risk group (36.8 ± 172.2 vs 17.7 ± 82.5; P < 0.001). The proportion of subjects with values of 30 ≤ ACR < 300 mg/g (11.9% vs 6.1%; P < 0.001) and ACR > 300 mg/g (2.1% vs 0.7%; P < 0.001) was significantly higher in high OSA risk group. Multivariate logistic regression results confirmed that microalbuminuria (OR 1.279, 95% confidence interval (CI) 1.068-1.532, P = 0.008) was significantly correlated with high OSA risk. In addition, significant correlation with high OSA risk was also found in macroalbuminuria (OR 1.684, 95% CI 1.073-2.530, P = 0.022) and proteinuria (OR 1.355, 95% CI 1.030-1.783, P = 0.030). We confirmed a significant correlation between high OSA risk and albuminuria/proteinuria in Korean adults. Therefore, renal function evaluation is required in high OSA risk patients, and OSA diagnosis through PSG test and treatment is necessary.

The pathogenesis of OSA-related hypertension: what are the determining factors?

Sleep-disordered breathing has a relatively high prevalence, which varies from 3-7% in males and from 2-5% in females in the adult population. Studies published in the literature have shown that sleep apnea is closely related to an increased risk of developing various pathologies, among which arterial hypertension stands out. The prevalence of hypertension in patients suffering from obstructive sleep apnea (OSA) ranges from 35-80% and appears to be related to OSA severity. Approximately 40-50% of patients affected by hypertension are also affected by OSA and this association seems to be stronger in young and middle-aged adults (<50 years of age). The primary objective of this narrative review is to provide an update on what are the main contributing comorbidities to the development of a hypertensive state in patients suffering from OSA, an independent risk factor for diurnal hypertension, implicated as a risk factor for the first stroke, recurrent stroke, and post-stroke mortality. There are a lot of factors that contribute to developing a hypertensive state in OSA patients, some more decisive, others less. More evidence from longitudinal studies is needed on the impact of OSA on cardiovascular risk in females, on the causal link between OSA and arterial hypertension or metabolic diseases, like diabetes and glucose intolerance, and the effect of different kinds of OSA treatment.

Commonalities and differences in carotid body dysfunction in hypertension and heart failure

Carotid body pathophysiology is associated with many cardiovascular-respiratory-metabolic diseases. This pathophysiology reflects both hyper-sensitivity and hyper-tonicity. From both animal models and human patients, evidence indicates that amelioration of this pathophysiological signalling improves disease states such as a lowering of blood pressure in hypertension, a reduction of breathing disturbances with improved cardiac function in heart failure (HF) and a re-balancing of autonomic activity with lowered sympathetic discharge. Given this, we have reviewed the mechanisms of carotid body hyper-sensitivity and hyper-tonicity across disease models asking whether there is uniqueness related to specific disease states. Our analysis indicates some commonalities and some potential differences, although not all mechanisms have been fully explored across all disease models. One potential commonality is that of hypoperfusion of the carotid body across hypertension and HF, where the excessive sympathetic drive may reduce blood flow in both models and, in addition, lowered cardiac output in HF may potentiate the hypoperfusion state of the carotid body. Other mechanisms are explored that focus on neurotransmitter and signalling pathways intrinsic to the carotid body (e.g. ATP, carbon monoxide) as well as extrinsic molecules carried in the blood (e.g. leptin); there are also transcription factors found in the carotid body endothelium that modulate its activity (Krüppel-like factor 2). The evidence to date fully supports that a better understanding of the mechanisms of carotid body pathophysiology is a fruitful strategy for informing potential new treatment strategies for many cardiovascular, respiratory and metabolic diseases, and this is highly relevant clinically.

Resistant hypertension: consensus document from the Korean society of hypertension

Although reports vary, the prevalence of true resistant hypertension and apparent treatment-resistant hypertension (aTRH) has been reported to be 10.3% and 14.7%, respectively. As there is a rapid increase in the prevalence of obesity, chronic kidney disease, and diabetes mellitus, factors that are associated with resistant hypertension, the prevalence of resistant hypertension is expected to rise as well. Frequently, patients with aTRH have pseudoresistant hypertension [aTRH due to white-coat uncontrolled hypertension (WUCH), drug underdosing, poor adherence, and inaccurate office blood pressure (BP) measurements]. As the prevalence of WUCH is high among patients with aTRH, the use of out-of-office BP measurements, both ambulatory blood pressure monitoring (ABPM) and home blood pressure monitoring (HBPM), is essential to exclude WUCH. Non-adherence is especially problematic, and methods to assess adherence remain limited and often not clinically feasible. Therefore, the use of HBPM and higher utilization of single-pill fixed-dose combination treatments should be emphasized to improve drug adherence. In addition, primary aldosteronism and symptomatic obstructive sleep apnea are quite common in patients with hypertension and more so in patients with resistant hypertension. Screening for these diseases is essential, as the treatment of these secondary causes may help control BP in patients who are otherwise difficult to treat. Finally, a proper drug regimen combined with lifestyle modifications is essential to control BP in these patients.

The effect of transcutaneous electrical stimulation of the submental area on the cardiorespiratory response in normal and awake subjects

Background: Electrical stimulation has recently been introduced to treat patients with Obstructive sleep apnoea There are, however, few data on the effects of transcutaneous submental electrical stimulation (TES) on the cardiovascular system. We studied the effect of TES on cardiorespiratory variables in healthy volunteers during head-down-tilt (HDT) induced baroreceptor loading.

Method: Cardiorespiratory parameters (blood pressure, heart rate, respiratory rate, tidal volume, airflow/minute ventilation, oxygen saturation, and end-tidal CO2/O2 concentration) were recorded seated, supine, and during head-down-tilt (50) under normoxic, hypercapnic (FiCO2 5%) and poikilocapnic hypoxic (FiO2 12%) conditions. Blood pressure (BP) was measured non-invasively and continuously (Finapres). Gas conditions were applied in random order. All participants were studied twice on different days, once without and once with TES.

Results: We studied 13 healthy subjects (age 29 (12) years, six female, body mass index (BMI) 23.23 (1.6) kg·m−2). A three-way ANOVA indicated that BP decreased significantly with TES (systolic: p = 4.93E-06, diastolic: p = 3.48E-09, mean: p = 3.88E-08). Change in gas condition (systolic: p = 0.0402, diastolic: p = 0.0033, mean: p = 0.0034) and different postures (systolic: 8.49E-08, diastolic: p = 6.91E-04, mean: p = 5.47E-05) similarly impacted on BP control. When tested for interaction, there were no significant associations between the three different factors electrical stimulation, gas condition, or posture, except for an effect on minute ventilation (gas condition/posture p = 0.0369).

Conclusion: Transcutaneous electrical stimulation has a substantial impact on the blood pressure. Similarly, postural changes and variations in inspired gas impact on blood pressure control. Finally, there was an interaction between posture and inspired gases that affects minute ventilation. These observations have implications on our understanding of integrated cardiorespiratory control, and may prove beneficial for patients with SDB who are assessed for treatment with electrical stimulation.

miR-485-5p alleviates obstructive sleep apnea syndrome with hypertension by inhibiting PI3K/AKT signaling pathway via downregulating HIF3A expression

OBJECTIVE

The obstructive sleep apnea syndrome (OSAS) is a risk factor for hypertension. MiRNAs are key regulators in hypertension. However, their roles in OSAS with hypertension remain unclear. This study aimed to clarify the function and mechanism of miRNAs in OSAS with hypertension.

METHODS

A chronic intermittent hypoxia (CIH) model was established to simulate OSAS with hypertension. The proliferation and migration of pulmonary artery smooth muscle cells (PASMCs) were assessed by CCK-8 and wound healing assays. qRT-PCR, Western blot, and immunofluorescence staining were used to detect the expression of HIF3A and PI3K/AKT pathway. Hematoxylin-eosin and Masson staining were used to detect the histopathological changes of pulmonary arterial hypertension (PAH). The regulatory function of miR-485-5p to HIF3A was assessed by dual luciferase reporter gene assay.

RESULTS

MiR-485-5p was significantly downregulated in the rats with OSAS-induced PAH. MiR-485-5p alleviated proliferation and migration of PASMCs in vitro and ameliorated OSAS-induced PAH in vivo. HIF3A could act as a target of miR-485-5p. HIF3A downregulation regulated by miR-485-5p alleviated proliferation and migration of PASMCs in vitro and ameliorated OSAS-induced PAH in vivo. In addition, we found that PI3K/AKT signaling was significantly inhibited in OSAS-induced PAH.

CONCLUSION

MiR-485-5p alleviates OSAS with hypertension by inhibiting the PI3K/Akt pathway via downregulating HIF3A expression through the PI3K/AKT pathway. These findings suggest that miR-485-5p has the potential for treating OSAS-associated hypertension.

[Obstructive sleep apnea syndrome and cardiovascular risk factors in the antihypertensive therapy "escape" phenomenon]

AIM

To assess the role of obstructive sleep apnea and other cardiovascular (CV) risk factors in the development of the antihypertensive therapy (AHT) efficacy "escape" phenomenon in patients with arterial hypertension (AH).

MATERIALS AND METHODS

The data of 75 patients with AH stage I-II, grades 1-3 were proceeded. All patients included in the study underwent night respiratory monitoring. After AHT prescription, blood pressure (BP) was monitored by three measurement methods (office, daily monitoring and self-control of blood pressure) - initially, in 1, 3 and 6 months after the inclusion - in order to confirm the initial therapy efficacy and to identify or exclude the "escape" phenomenon.

RESULTS

In 36.0% of patients, the "escape" phenomenon was diagnosed in 1 or 3 months of observation. When comparing the group with the "escape" phenomenon, an initially higher level of systolic BP was revealed according to office measurements, 24-hour monitoring and self-control BP monitoring (134.0±4.7 mmHg vs 126.0±8.5 mmHg; 129.0±2.3 mmHg vs 121.0±7.7 mmHg; 131.0±8.2 mmHg vs 121.5±6.2 mmHg resp.; р<0,05). There were no differences in sleep apnea and CV risk factors between the groups. However in patients with a minimal SpO₂≤85% during sleep, there were a higher levels of office systolic BP both before the AHT prescription, and during its use (157.6±10.4 mmHg vs 152.4±8.1 mmHg resp., р<0,05; 132.0±6.8 vs 127.1±8.9 mmHg resp.; р<0,05), and mean 24-hour systolic BP (125.7±5.9 vs 121.6±8.2 mmHg resp.; р<0,05) - compared with patients with a minimum SpO₂>85%.

CONCLUSION

The higher BP level in patients with lover nocturnal hypoxemia does not allow us to exclude the delayed negative impact of obstructive sleep apnea, especially severe, on the BP profile in case of initially successful AH control.

Association between arterial stiffness and sleep apnoea in patients with resistant hypertension

Resistant Hypertension (RHT) is associated with a higher risk of Obstructive Sleep Apnoea (OSA). OSA and aortic stiffness (AS) measured by Pulse Wave Velocity (PWV) are independent risk factors for cardiovascular events. We assessed, in a cross-sectional study, the association between AS measured by PWV and OSA severity in patients with RHT. All patients were submitted to polysomnography, PWV measure and 24 h ABPM. Bivariate analysis compared patients with and without moderate/severe OSA. Multivariate analysis was performed to assess the independent correlates of moderate/severe OSA. A total of 376 patients were included, 31% were men with a mean age of 63 ± 10 years. Moderate/severe OSA was diagnosed in 214 patients (57%), 63 patients (17%) presented AS. Uncontrolled ABPM (true RHT) was found in 215 patients (57.2%) and among them 113 were diagnosed with moderate/severe OSA. Evaluating AS in patients with mild, moderate and severe apnoea, we observed a progressive increase in PWV (8.19 ± 1.55, 8.51 ± 1.84, 8.67 ± 1.68, respectively). Classifying them in 2 groups: (1) without apnoea/mild apnoea and (2) moderate/severe apnoea, we found higher values in group 2 (8.21 ± 1.52 m/s vs. 8.60 ± 1.75 m/s, p = 0.02), especially among true RHT patients (8.28 ± 1.62 vs. 8.81 ± 1.86, p = 0.029), women (8.13 ± 1.49 vs. 8.55 ± 1.73, p = 0.036), and uncontrolled nocturnal systolic BP (8.49 ± 1.63 vs. 8.58 ± 1.78, p = 0.04). In conclusion, in this RHT cohort, although with borderline results, the more severe the apnoea, the greater the arterial stiffness, mainly among women, true RHT and patients with an adverse nocturnal BP profile.

Cardiorespiratory alterations following intermittent photostimulation of RVLM C1 neurons: Implications for long-term blood pressure, breathing and sleep regulation in freely moving rats

AIM

Sympathoexcitation and sleep-disordered breathing are common contributors for disease progression. Catecholaminergic neurons from the rostral ventrolateral medulla (RVLM-C1) modulate sympathetic outflow and have anatomical projections to respiratory neurons; however, the contribution of highly selective activation of RVLM-C1 neurons on long-term autonomic and breathing (dys)regulation remains to be understood.

METHODS

To explore this relationship, a lentiviral vector carrying the light-sensitive cation channel channelrhodopsin-2 (LVV-PRSX8-ChR2-YFP) was unilaterally injected into the RVLM of healthy rats. On the contralateral side, LVV-PRSX8-ChR2-YFP was co-injected with a specific immunotoxin (DβH-SAP) targeted to eliminate C1 neurons.

RESULTS

Intermittent photostimulation of RVLM-C1 in vivo, in unrestrained freely moving rats, elicited long-term facilitation of the sympathetic drive, a rise in blood pressure and sympatho-respiratory coupling. In addition, photoactivation of RVLM-C1 induced long-lasting ventilatory instability, characterized by oscillations in tidal volume and increased breathing variability, but only during non-rapid eye movement sleep. These effects were not observed when photostimulation of the RVLM was performed in the presence of DβH-SAP toxin.

CONCLUSIONS

The finding that intermittent activation of RVLM-C1 neurons induces autonomic and breathing dysfunction suggest that episodic stimulation of RVLM-C1 may serve as a pathological substrate for the long-term development of cardiorespiratory disorders.

Etiology and Management of Treatment-Resistant Hypertension in African American Adults ≥18 Years: A Literature Review

Treatment-resistant hypertension (TRH) is defined as blood pressure levels that remain above the therapeutic goal despite concurrent use of three or more antihypertensive medications taken at maximally tolerated doses, one of which should be a diuretic. Additionally, individuals on four or more antihypertensive agents regardless of blood pressure are also considered to have TRH. Amongst people diagnosed with TRH, African American adults face a huge management gap, resulting in increased cardiovascular disease risk. The primary objective of this review was to identify the commonly encountered etiologies and extensively discuss the current management strategies of TRH with a particular focus on African Americans. Relevant studies were identified by analyzing scientific databases and journals such as PubMed, Cochrane, MEDLINE, Cureus, and American Heart Association (AHA). The studies identified and examined common causes of TRH, describing their pathophysiology and highlighting different treatment options for the respective etiologies. The most prevalent etiologies of TRH amongst African Americans were chronic kidney disease (CKD), renal artery stenosis (RAS), fibromuscular dysplasia, obstructive sleep apnea (OSA), endocrine causes (Conn syndrome, Cushing syndrome, etc.), sympathetic nervous system overactivity, lifestyle factors, inaccurate blood pressure measurement, and inappropriate treatment. Of the etiologies reviewed, OSA, lifestyle factors, and CKD exhibited a striking prevalence among the subpopulation studied. Unfortunately, there was a paucity of articles addressing this topic amongst African Americans, and therefore there was not a substantial appreciation of the prevalence of some of the identified etiologies in the population of interest. Thorough diagnostic testing for associated or underlying conditions provides a basis for successful management. This review brought to the fore the need for doctors and patients to collaborate in order to improve TRH management and help patients lead healthier lives.

miR-199a-5p Relieves Obstructive Sleep Apnea Syndrome-Related Hypertension by Targeting HIF-1α

Introduction. Obstructive sleep apnea syndrome (OSAS) is related to hypertension. Vascular remodeling is both the pathogenesis and the structural change basis of OSAS-related hypertension. Exploring miRNA functioning in OSAS-related hypertension may offer novel diagnostic and therapeutic targets for controlling hypertension-associated cardiovascular diseases. However, the role of miR-199a-5p in OSAS-related hypertension has not been demonstrated yet. Methods. In this study, we investigated the role of miR-199a-5p and HIF-1α in OSAS-related hypertension by performing in vitro cell experiments and in vivo animal experiments. Rat aortic smooth muscle cells (A7r5) were cultured under hypoxia as an in vitro model. To establish the animal model of OSAS-related hypertension, the rats were under exposure to chronic intermittent hypoxia (CIH) in a hypoxic instrument. The rats were randomly grouped into normal, CIH, CIH+NC, and CIH+miR-199a-5p. Results. By establishing an animal model, we found decreased miR-199a-5p expression and increased HIF-1α expression in OSAS with hypertension. The overexpressed miR-199a-5p could reduce systolic blood pressure and relieve oxidase stress and inflammation. miR-199a-5p treatment could overturn the upregulation of HIF-1α and TGF-β1 and downregulation of α-SMA. Overexpressed miR-199a-5p might attenuate vascular remodeling through HIF-1α downregulation. miR-199a-5p/HIF-1α may inhibit proliferation of vascular smooth muscle cells under hypoxia. Conclusion. miR-199a-5p may relieve OSAS-related hypertension by targeting HIF-1α and be a novel potential therapeutic target.

Nocturnal nasal congestion is associated with uncontrolled blood pressure in patients with hypertension comorbid obstructive sleep apnea

OBJECTIVE

To determine the independent role of nasal obstruction on blood pressure (BP) control in patients with hypertension comorbid obstructive sleep apnea (OSA).

SUBJECTS AND METHODS

This cross-sectional study comprised of 326 newly diagnosed OSA comorbid hypertension patients from March 2018 to December 2021. Sixty-six patients have controlled hypertension, two hundred and nine with uncontrolled hypertension and fifty-one with resistant hypertension. Information on demographic characteristics, sleep data, hypertension status was collected. Multivariate logistic regression models were used to determine the odds ratios (OR).

RESULTS

Patients with nocturnal nasal congestion had more difficult to control blood pressure, with more numbers of antihypertensive drugs. They tended to have more severe OSA, lower nocturnal oxygen saturation and more severe sleepiness. Univariate analysis showed that nocturnal nasal congestion and Nasal Obstruction Symptom Evaluation (NOSE) Scale scores were associated with uncontrolled BP. After adjusting for age, sex, smoking, alcohol use, OSA severity and CT90, multivariate logistic analysis models showed that nocturnal nasal congestion was independently associated with uncontrolled hypertension (OR = 2.09, p = 0.023). When analyzed more severe resistant hypertension, nocturnal nasal congestion showed a higher association (OR = 2.96, p = 0.014).

CONCLUSION

This cross-sectional study demonstrated that the nocturnal nasal congestion was independently associated with uncontrolled BP. The use of nasal decongestants or nasal surgery may be a potential therapeutic target for resistant hypertension in the future.

Sex-Related Differences in Polygraphic Parameters in a Population of Patients with Obstructive Sleep Apnea Syndrome

BACKGROUND

Sex-related differences in the prevalence and clinical presentation of Obstructive Sleep Apnea Syndrome (OSAS) have been widely documented. The aim of this study was to investigate the influence of patients' sex on polygraphic parameters with particular attention to sleep autonomic changes in a population of OSAS patients.

METHODS

Sixty OSAS patients aged 55-65 years (30 men, 30 women) were enrolled. Sleep quality was assessed with the Pittsburgh Sleep Quality Index (PSQI) and daytime sleepiness with the Epworth Sleepiness Scale (ESS). The presence of respiratory events and autonomic changes during the night was investigated by polygraphy.

RESULTS

Similar main cardiovascular risk factors prevalence was observed in both men and women. We observed a significant difference in PSQI (higher in women, p=0.0001) and ESS (higher in men, p=0.004) scores. Snoring (p=0.033), supine AHI (p=0.004), T90 (p=0.021), LO2 (p=0.0001), LF/HF ratio and LF (p=0.0001) were significantly higher in men. Sex differences in PSQI mean score and LF/HF ratio variability were preserved in all the subgroups of OSA severity.

CONCLUSION

The influence of sex in modulating cardiovascular risk is a widely discussed topic. In our study, men showed more severe polygraphic parameters and an increase in LF/HF ratio compared to women. The results of our investigation suggest the relevance of delivering information about the different expressions of OSAS in men and women in order to improve diagnostic skills and in-depth prevention approaches.

[Treatment-Emergent Central Sleep Apnea - Detection and Treatment]

Treatment-Emergent Central Sleep Apnea - Detection and Treatment Abstract. In treatment-emergent central sleep apnea (TECSA), affected patients with obstructive sleep apnea newly develop central sleep apnea (AHI central ≥5/h) under therapy with positive pressure ventilation which cannot be explained by other causes. The pathophysiology of TECSA is incompletely understood. PaCO2 and the associated apnea threshold seem to play a central role. The incidence of TECSA varies (1.8-20%), and in about 2/3 of cases it is self-limiting in the course of the therapy. If persistence or new onset occurs later in the course of positive pressure therapy, a further evaluation (e.g., echocardiography, neurologic examination, medication history) is indicated. Effective treatment options include a change in ventilation therapy (adaptive servoventilation or bilevel ventilation with back-up frequency) or additional nocturnal oxygen supplementation; these options should be decided case by case.

Nocturnal blood pressure surge in seconds is a new determinant of left ventricular mass index

Nocturnal blood pressure (BP) surge in seconds (sec‐surge), which is characterized as acute transient BP elevation over several tens of seconds, could be a predictor of target organ damage. However, it is not clear that the severity of sec‐surge is different between sec‐surges induced by sleep apnea (SA) (apnea/hypopnea detected by polysomnography (PSG) or oxygen desaturation) and those induced by non‐SA factors (rapid eye movement, micro arousal, etc.), and sec‐surge variables associate with left ventricular hypertrophy (LVH) independently of conventional BP variables. The authors assessed these points with 41 patients (mean age 63.2±12.6 years, 29% female) who underwent full PSG, beat‐by‐beat (BbB) BP, and cuff‐oscillometric BP measurement during the night. All patients were included for the analysis comparing sec‐surge severity between inducing factors (SA and non‐SA factors). There were no significant differences in the number of sec‐surges/night between SA‐related sec‐surges and non‐SA‐related sec‐surges (19.5±26.0 vs. 16.4±29.8 events/night). There were also no significant differences in the peak of sec‐surges, defined as the maximum systolic BPs (SBPs) in each sec‐surge, between SA‐related sec‐surges and non‐SA‐related sec‐surges (148.2±18.5 vs. 149.3±19.2 mm Hg). Furthermore, as a result of multiple regression analysis (n = 18), the peak of sec‐surge was significantly and strongly associated with the left ventricular mass index (standardized β = 0.62, p = .02), compared with the mean nocturnal SBPs measured by oscillometric method (β = −0.04, p = .87). This study suggests that peak of sec‐surge could be a better predictor of LVH compared to parameters derived from regular nocturnal oscillometric SBP.

Obstructive sleep apnea and associated factors among hypertensive patients attending a tertiary cardiac center in Tanzania: a comparative cross-sectional study

Background

There is mounting evidence for a reciprocal yet bidirectional association between sleep-disordered breathing and hypertension. Obstructive sleep apnea (OSA), a common cause of systemic hypertension is an independent risk factor for hypertension-related cardiovascular morbidity and mortality. In this comparative hospital-based cross-sectional study, we sought to explore the burden of obstructive sleep apnea and its associated risk factors among hypertensive patients attending Jakaya Kikwete Cardiac Institute.

Methodology

A total of 1974 individuals (i.e. 1289 hypertensive and 685 normotensives) were consecutively enrolled in this study. The Berlin questionnaire and Epworth Sleepiness Scale were utilized in the assessment of OSA and excessive daytime sleepiness (EDS) respectively. Logistic regression analyses were employed in the determination of associated factors for OSA.

Results

The mean age was 53.4 years and females constituted the large majority (60.4%) of participants. About three quarters (74.1%) of participants had excess body weight, 11.6% had diabetes, 8.0% had asthma and 18.6% had history of recurrent nasal congestion. Positive family history of snoring was reported by 43.1% of participants and 36.9% had a personal history of snoring. Persons with hypertension displayed a higher frequency (42.1%) of OSA compared to their normotensive counterparts (11.8%), p < 0.001. Multivariate logistic regression analyses revealed hypertension (OR 5.1, 95% CI 3.2-8.2, p < 0.001), diabetes mellitus (OR 2.2, 95% CI 1.3-3.5, p < 0.01), chronic nasal congestion (OR 1.6, 95% CI 1.1-2.5, p = 0.01), obesity (OR 2.4, 95% CI 1.8-3.3, p < 0.001), increased neck circumference (OR 2.7, 95% CI 1.2-6.4, p = 0.02), family history of snoring (OR 5.5, 95% CI 4.0-7.5, p < 0.001), and working > 8 h/24 h (OR 0.6, 95% CI 0.4-1.0, p = 0.03) to have an independent association for OSA. Furthermore, participants with hypertension displayed superior odds for OSA compared to their normotensive counterparts across all subgroup analyses.

Conclusion

OSA is considerably common among patients with hypertension in a tertiary health care setting in Tanzania. Positive family history of snoring was the strongest associated factor; however, excess body weight proved to be the strongest modifiable risk factor. In view of its pervasiveness, OSA should be an integral part of the medical evaluation in hypertensive individuals.

Aryl Hydrocarbon Receptor and Cysteine Redox Dynamics Underlie (Mal)adaptive Mechanisms to Chronic Intermittent Hypoxia in Kidney Cortex

We hypothesized that an interplay between aryl hydrocarbon receptor (AhR) and cysteine-related thiolome at the kidney cortex underlies the mechanisms of (mal)adaptation to chronic intermittent hypoxia (CIH), promoting arterial hypertension (HTN). Using a rat model of CIH-HTN, we investigated the impact of short-term (1 and 7 days), mid-term (14 and 21 days, pre-HTN), and long-term intermittent hypoxia (IH) (up to 60 days, established HTN) on CYP1A1 protein level (a sensitive hallmark of AhR activation) and cysteine-related thiol pools. We found that acute and chronic IH had opposite effects on CYP1A1 and the thiolome. While short-term IH decreased CYP1A1 and increased protein-S-thiolation, long-term IH increased CYP1A1 and free oxidized cysteine. In addition, an in vitro administration of cystine, but not cysteine, to human endothelial cells increased Cyp1a1 expression, supporting cystine as a putative AhR activator. This study supports CYP1A1 as a biomarker of obstructive sleep apnea (OSA) severity and oxidized pools of cysteine as risk indicator of OSA-HTN. This work contributes to a better understanding of the mechanisms underlying the phenotype of OSA-HTN, mimicked by this model, which is in line with precision medicine challenges in OSA.

Role of Nitric Oxide in Neurodegeneration: Function, Regulation, and Inhibition

Reactive nitrogen species (RNS) and reactive oxygen species (ROS), collectively known as reactive oxygen and nitrogen species (RONS), are the products of normal cellular metabolism and interact with several vital biomolecules including nucleic acid, proteins, and membrane lipids and alter their function in an irreversible manner which can lead to cell death. There is an imperative role for oxidative stress in the pathogenesis of cognitive impairments and the development and progression of neural injury. Elevated production of higher amounts of nitric oxide (NO) takes place in numerous pathological conditions, such as neurodegenerative diseases, inflammation, and ischemia, which occur concurrently with elevated nitrosative/oxidative stress. The enzyme nitric oxide synthase (NOS) is responsible for the generation of NO in different cells by conversion of L-arginine (Arg) to L-citrulline. Therefore, the NO signaling pathway represents a viable therapeutic target. Naturally occurring polyphenols targeting the NO signaling pathway can be of major importance in the field of neurodegeneration and related complications. Here, we comprehensively review the importance of NO and its production in the human body and afterwards highlight the importance of various natural products along with their mechanisms against various neurodegenerative diseases involving their effect on NO production.

Treating sleep disorders to improve blood pressure control and cardiovascular prevention: a dream come true?-a narrative review

Hypertension is one of the primary risk factors for heart disease and stroke, the leading causes of death worldwide. Current evidence supports the treatment of high blood pressure (BP) values in order to obtain a substantial reduction of cardiovascular burden. Sleep plays an important role in maintaining nocturnal BP control and nocturnal hypertension which, in turn, can be affected by the presence of sleep disorders. Whilst respiratory disturbances have been extensively studied and their causal role in the development of nocturnal hypertension has been demonstrated in both cross sectional and prospective studies, less is known about the impact of other sleep disorders such as insomnia. In this review, we aim to describe the role of sleep disorders in the development of nocturnal and diurnal hypertension. Furthermore, we aim to discuss the potential impact of the treatment of such sleep disorders on BP values as an adjunct treatment for patients with hypertension.

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

A Guide to Management of Sleepiness in ESKD

Daytime sleepiness, also known as hypersomnolence, is common among patients receiving maintenance dialysis and following successful kidney transplantation. Sleepiness may be secondary to medical comorbid conditions, medication side effect, insufficient sleep syndrome, and sleep-disordered breathing or the result of a primary central disorder of hypersomnolence, such as narcolepsy. Unrecognized and untreated sleep disorders are associated with substantial morbidity and mortality among patients with end-stage kidney disease. Effective management of hypersomnolence can improve quality of life in patients with kidney disease. This review focuses on the principal causes of sleepiness in patients with end-stage kidney disease. Awareness of these disorders by treating nephrologists is crucial. This review provides a systematic approach to guide providers through the recognition, early diagnosis, and treatment of hypersomnolence, which is commonly encountered in this patient population. Areas of future research are also suggested.

Impact of obstructive sleep apnea on silent cerebral small vessel disease: a systematic review and meta-analysis

BACKGROUND

Cerebral small vessel disease (CSVD) is a well-known cause of vascular dementia, a leading medical morbidity in the aging population. Obstructive sleep apnea (OSA) has been validated as a cardiovascular risk factor. However, the relationship between these two clinical syndromes is not well established. We aimed to assess the association between OSA and CSVD.

METHODS

Databases were searched from inception through May 2019. Studies that reported incidence or odd ratios of CSVD in patients with OSA were included. Effect estimates from the individual studies were extracted and combined using random-effect, generic inverse variance method of DerSimonian and Laird.

RESULTS

A total of 14 observational studies comprising of 4335 patients were included into the analysis. Compared to patients without OSA, patients with OSA were significantly associated with CSVD magnetic resonance imaging (MRI) findings of white matter hyperintensity (WMH) and asymptomatic lacunar infarction (ALI) with a pooled OR of 2.31 (95% confidence interval [CI], 1.46-3.66, I² = 79%) and 1.78 (95% CI, 1.06-3.01, I² = 41%), respectively. However, there was no significant association between OSA and findings of cerebral microbleeds (CMBs), with a pooled odds ratio (OR) of 2.15 (95% CI, 0.64-7.29, I² = 55%).

CONCLUSIONS

Our study demonstrated the association between OSA and CSVD MRI findings of white matter hyperintensity (WMH) and asymptomatic lacunar infarction (ALI) when compared to patients without OSA. The absence of an association of CMBs findings with OSA could be due either by a lower sensitivity of neuroimaging techniques utilized to detect CMBs or a potentially different pathogenesis of CMBs.

Is Obstructive Sleep Apnea Associated With Progressive Glaucomatous Optic Neuropathy?

PURPOSE

The purpose of this study was to evaluate the relationship between obstructive sleep apnea syndrome (OSAS) and glaucoma progression, and to examine the correlation between OSAS severity and rate of visual field (VF) loss.

METHODS

Patients with concurrent diagnoses of open-angle glaucoma and OSAS between 2010 and 2016 were identified. Enrollment criteria consisted of glaucomatous optic neuropathy and VF loss, ≥5 reliable VFs, ≥2 years of follow-up, and polysomnography (PSG) within 12 months of final VF. PSG parameters including apnea-hypopnea index (AHI) and oxygen saturation (SpO2) were collected. Eyes were classified as "progressors" or "nonprogressors" based upon event analysis using Glaucoma Progression Analysis criteria. Two-tailed t test comparisons were performed, and correlations between rates of VF loss and PSG parameters were assessed.

RESULTS

A total of 141 patients with OSAS and glaucoma were identified. Twenty-five patients (age 67.9±7.6 y) with OSAS (8 mild, 8 moderate, 9 severe) were enrolled. Eleven eyes (44%) were classified as progressors, and had more severe baseline VF loss (P=0.03). Progressors and nonprogressors had nonsignificantly different (P>0.05) age (69.9±8.7 vs. 66.4±6.6 y), follow-up (4.4±0.7 vs. 4.3±1.0 y), intraocular pressure (13.1±2.8 vs. 14.9±2.5 mm Hg), mean ocular perfusion pressure (49.7±5.5 vs. 48.8±9.0 mm Hg), AHI (31.3±18.6 vs. 26.4±24.0), body-mass index (27.8±5.5 vs. 28.8±5.6), and SpO2 (94.1±1.6% vs. 94.0±1.6%). AHI was not correlated with slopes of VF mean deviation (r, -0.271; P, 0.190) or pattern standard deviation (r, 0.211; P, 0.312), and no substantial increase in risk of progression was found with increase in AHI.

CONCLUSIONS

This study does not support a relationship between OSAS and glaucomatous progression. No correlation was observed between OSAS severity and rate of VF loss.

Hypertension and atrial fibrillation in obstructive sleep apnea: Is it a menopause issue?

Obstructive sleep apnoea (OSA) is a common disorder, in which loss of pharyngeal dilator muscle tone during sleep causes recurrent collapse of the upper airway and temporary cessation of breathing. Repeated apneas and hypopneas lead to cycles of intermittent hypoxia/hypercapnia, increased negative intrathoracic pressure and arousals from sleep. These consequences of OSA are associated with a cascade of cardiovascular and neurohumoral consequences, including sympathetic nervous system hyperactivity, raised heart rate variability, increases in blood pressure, myocardial wall stress, oxidative stress, systemic inflammation, platelet aggregation and impaired vascular endothelial function, which contribute, in turn, to increased cardiovascular risk and, in particular, to the development of chronic systemic arterial hypertension and arrhythmias, especially atrial fibrillation (AF). Given that the prevalence of OSA is modified by age and gender, OSA-related cardiovascular diseases may also be affected by the same factors. This review focuses on the potential role of OSA in systemic arterial hypertension and AF, and discusses the most interesting studies on age and gender as predisposing factors.

Bone Metabolic Markers in Patients with Obstructive Sleep Apnea Syndrome

Background:

Obstructive sleep apnea syndrome (OSAS) is prevalent in obesity and is associated with many metabolic abnormalities. The relationship between OSAS and bone metabolism is still unclear. The aim of this study was to investigate the relationship between the severity of OSAS and bone metabolic markers.

Methods:

A total of 119 obese males were enrolled in this study in spring months from 2015 to 2017. All candidates underwent polysomnography, and their bone mineral density (BMD) and the serum levels of total procollagen type 1 N-terminal propeptide (t-P1NP), N-terminal midfragment of osteocalcin (N-MID), β-C-terminal telopeptide of type 1 collagen (β-CTX), vitamin D (VD), and parathyroid hormone (PTH) were measured. The analysis of variance and Pearson correlation analysis were performed for data analyses.

Results:

No significant differences in the mean values of BMD were observed among the obesity, mild-to-moderate OSAS, and severe OSAS groups; and the serum levels of t-P1NP and β-CTX in the severe OSAS group were significantly higher than those in the obesity group (48.42 ± 23.78 ng/ml vs. 31.98 ± 9.85 ng/ml, P < 0.001; 0.53 ± 0.24 ng/ml vs. 0.41 ± 0.13 ng/ml, P = 0.011, respectively). The serum level of VD in the obesity group was significantly higher than those in the mild-to-moderate and severe OSAS groups (both P < 0.001), and decreased as the severity of OSAS increased (P < 0.001). The serum level of PTH in the severey and mild-to-moderate OSAS groups (both P < 0.001). The results of correlation analysis indicated that the level of apnea-hypopnea index (AHI) was correlated with the levels of t-P1NP (r = 0.396, P < 0.001), VD (r = –0.404, P < 0.001), and PTH (r = 0.400, P < 0.001), whereas the level of minimum O₂ saturation (SaO₂ min) was correlated with the levels of VD (r = 0.258, P = 0.016) and PTH (r = –0.376, P < 0.001).

Conclusions:

The levels of bone resorption and formation markers in patients with severe OSAS were significantly increased compared to obese men, and the severity of OSAS was correlated with the serum levels of t-P1NP, VD, and PTH.

Systemic hypertension in obstructive sleep apnea

There is consistent epidemiological evidence that sleep disordered breathing and systemic arterial hypertension are deeply associated, being linked through a bidirectional complex interaction among multiple mechanisms including autonomic nervous system alterations, inflammation, hormonal and hemodynamic components, sleep alterations. However there are several unanswered questions not only from a pathophysiological perspective, but also regarding the effects of obstructive sleep apnea (OSA) treatment on arterial blood pressure values. At present, while many studies have supported the possibility to obtain at least a small blood pressure reduction with OSA treatment, in particular in hypertensive patients, large trials have not clearly confirmed a significant anti-hypertensive effect, nor a beneficial effect of this intervention on cardiovascular endpoints including cardiovascular mortality. Aim of the present review article is to address the relationship between OSA and hypertension in the light of the latest evidence in the field. Moreover we will discuss research topics which need to be investigated in the future, in order to better clarify still pending issues with the aim of obtaining an early diagnosis, a more suitable phenotyping including comorbidities, and better strategies to improve patients' compliance and adherence to treatment.

Analysis of OSAS incidence and influential factors in middle-aged and elderly patients with hypertension

BACKGROUND

To investigate the detection rate and influencing factors of obstructive sleep apnea syndrome (OSAS) in middle-aged and elderly patients with hypertension.

METHODS

A total of 440 patients with hypertension were selected as the research objects, all of them participated in the Berlin questionnaire survey, and the polysomnography (PSG) was performed on the patients with a high risk of OSAS. The detection rate of OSAS was analyzed, the clinical data between non-OSAS group and OSAS group were compared and stepwise linear regression and logistic regression were used to analyze the related influencing factors to Apnea Hypopnea Index (AHI) and OSAS in hypertensive patients.

RESULTS

A total of 235 patients completed PSG and 196 patients were diagnosed as OSAS with the detection rate of 83.40%. The detection rate of OSAS in male patients was higher than that in females (89.04% vs.74.16%, χ2=8.025, P=0.006). The detection rates of OSAS in normal BMI group, overweight group and obesity group were 56.52%, 92.37% and 100%, respectively (χ2=36.438, P<0.001). The detection rates of OSAS in normal waistline group and central obesity group were 74.42% and 88.59% (χ2=7.539, P=0.016). The detection rates of OSAS in grade 1, grade 2, and grade 3 hypertension groups were 57.47%, 98.23%, and 100%, respectively (χ2=44.623, P<0.001). BMI, systolic blood pressure (SBP), diastolic blood pressure (DBP), low density lipoprotein (LDL) and waist circumference of OSAS group were all higher than those in non-OSAS group (P<0.05). BMI, SBP and DBP were positively correlated with AHI (P<0.05), which were independent risk factors of OSAS (OR=2.548 [95% CI: 1.449-4.327], 1.342 [95% CI: 1.214-1.965] and 1.169 [95% CI: 1.025-1.622], respectively, P<0.05).

CONCLUSIONS

The incidence of OSAS in middle-aged and elderly patients with hypertension is high. High BMI, SBP, and DBP are independent risk factors of OSAS.

Gamma-glutamyl transferase activity as a predictive marker for severity of obstructive sleep apnea syndrome and concomitant hypertension

BACKGROUND

Chronic intermittent hypia, inflammation and oxidative stress are involved in resultant obstructive sleep apnea syndrome (OSAS), which may affect numerous regulatory mechanisms that play a role in the regulation of blood pressure. Gamma-glutamyl transferase (GGT) is a novel marker in the prediction of cardiovascular risk.

OBJECTIVE

The objective of this study was to investigate the correlation of serum levels of GGT with hypertension and the degree of the upper airway obstruction in subjects with OSAS.

METHODS

A total of 270 subjects that met the inclusion criteria were enrolled in the study. The subjects were divided into four separate groups according to the apnea-hypopnea index (AHI) scores as the control group (AHI < 5), mild OSAS group (AHI 5-15), moderate OSAS group (AHI 16-30) and severe OSAS group (AHI >30). A further classification of the OSAS subjects was made in two groups based on the presence of hypertension.

RESULTS

The study included 43 control individuals and 59 subjects with mild, 54 subjects with moderate and 114 subjects with severe OSAS. The serum levels of GGT were found to be significantly correlated with OSAS severity (control group: 18 ± 3.3, mild OSAS: 23.6 ± 7.3, moderate OSAS: 26.4 ± 7.5 and severe OSAS: 39.8 ± 12). Serum levels of GGT were found to be significantly higher in OSAS subjects with concomitant hypertension than in the group without associated hypertension (P < .05). The results showed that the adjusted mean GGT under OSA without hypertension (M_adj  = 28.76, SE = 0.71) was significantly lower than in cases with OSA with hypertension (M_adj  = 42.79, SE = 1.19).

CONCLUSION

The present study indicated a strong correlation between high serum levels of GGT and concomitant hypertension in subjects with obstructive sleep apnea. This biomarker may be helpful in grading the severity of obstructive sleep apnea and correlated with hypertension in this population.

Intermittent hypoxia causes histological kidney damage and increases growth factor expression in a mouse model of obstructive sleep apnea

Epidemiological studies demonstrate an association between obstructive sleep apnea (OSA) and accelerated loss of kidney function. It is unclear whether the decline in function is due to OSA per se or to other confounding factors such as obesity. In addition, the structural kidney abnormalities associated with OSA are unclear. The objective of this study was to determine whether intermittent hypoxia (IH), a key pathological feature of OSA, induces renal histopathological damage using a mouse model. Ten 8-week old wild-type male CB57BL/6 mice were randomly assigned to receive either IH or intermittent air (IA) for 60 days. After euthanasia, one kidney per animal was paraformaldehyde-fixed and then sectioned for histopathological and immunohistochemical analysis. Measurements of glomerular hypertrophy and mesangial matrix expansion were made in periodic acid–Schiff stained kidney sections, while glomerular transforming growth factor-β1 (TGF-β1), connective tissue growth factor (CTGF) and vascular endothelial growth factor-A (VEGF-A) proteins were semi-quantified by immunohistochemistry. The antigen-antibody reaction was detected by 3,3′-diaminobenzidine chromogen where the color intensity semi-quantified glomerular protein expression. To enhance the accuracy of protein semi-quantification, the percentage of only highly-positive staining was used for analysis. Levels of TGF-β, CTGF and VEGF-A proteins in the kidney cortex were further quantified by western blotting. Cellular apoptosis was also investigated by measuring cortical antiapoptotic B-cell lymphoma 2 (Bcl-2) and apoptotic Bcl-2-associated X (Bax) proteins by western blotting. Further investigation of cellular apoptosis was carried out by fluorometric terminal deoxynucleotidyl transferase (TdT) dUTP Nick-End Labeling (TUNEL) staining. Finally, the levels of serum creatinine and 24-hour urinary albumin were measured as a general index of renal function. Our results indicate that mice exposed to IH have an increased glomerular area (by 1.13 fold, p< 0.001) and expansion of mesangial matrix (by 1.8 fold, p< 0.01). Moreover, the glomerular expressions of TGF-β1, CTGF and VEGF-A proteins were 2.7, 2.2 and 3.8-fold higher in mice exposed to IH (p< 0.05 for all). Furthermore, western blotting protein analysis demonstrates that IH-exposed mice express higher levels of TGF-β1, CTGF and VEGF-A proteins by 1.9, 4.0 and 1.6-fold (p< 0.05 for all) respectively. Renal cellular apoptosis was greater in the IH group as shown by an increased cortical Bax/Bcl-2 protein ratio (p< 0.01) and higher fluorometric TUNEL staining (p< 0.001). Finally, 24-hr urinary albumin levels were higher in mice exposed to IH (43.4 μg vs 9.7 μg, p< 0.01), while there were no differences in serum creatinine levels between the two groups. We conclude that IH causes kidney injury that is accompanied by glomerular hypertrophy, mesangial matrix expansion, increased expression of glomerular growth factors and an increased cellular apoptosis.

Study on the Short-Time Remolding of Upper Airway After Uvulopalatopharyngoplasty

OBJECTIVE

To verify the short-time remolding of upper airway in patients diagnosed with obstructive sleep disordered breathing after Uvulopalatopharyngoplasty (UPPP).

METHODS

Twenty-one male adult patients aged 27 to 52 years followed up ranged from preoperation to 6 months after the operation. Lateral cephalometric radiographs (conventional and when pronouncing "i") were obtained 2 weeks preoperatively, 3 days postoperatively, and 1, 2, 3, 6 months after the surgery. The anterolateral diameters of different levels of upper airway and parameters of hyoid position of the patients were then measured. SAS 8.02 was used to analyze the differences by time.

RESULTS

The study illustrated that the UPPP major affected the velopharyngeal and glossopharyngeal areas: parameters wane (P <0.05). On the other hand, UPPP leaded to the decline and retreat of hyoid. Most of the parameters remained metabolic. The nasopharynx kept statical (P >0.05) while the velopharyngeal parameters were increasing (P <0.05). The glossopharyngeal parameters increased in the first month after UPPP (P <0.05), while hypopharyngeal parameters underwent decline since 2 months after UPPP (P <0.05). The hyoid obtained decline and retreat (P <0.05) overall, while it endured a short-time climb in the first month after UPPP (P <0.05).

CONCLUSION

Short-time upper airway remolding after UPPP existed.

Among middle-aged adults, snoring predicted hypertension independently of sleep apnoea

Objective

While the link between obstructive sleep apnoea (OSA) and hypertension is well established, the relationships between snoring, OSA, and hypertension remain unclear. This study aimed to evaluate the association between hypertension and snoring independently of OSA.

Methods

Adults with sleep difficulties underwent a one-night polysomnographic sleep assessment, including a thorough assessment of apnoea and snoring. Upon waking, blood pressure was measured, the measurement repeated after 15 min, in a resting position. Anthropometric data were recorded. Hypertension was defined as blood pressure ≥140/90 mmHg or the use of antihypertensive medications.

Results

The study enrolled 181 adults (mean age 48.8 years; 119 males). Snoring, apnoea, blood pressure and anthropometric dimensions were highly associated. Patients with hypertension had higher levels of snoring and apnoea, as well as indicators of excess weight. Snoring was the most robust predictor of hypertension.

Conclusions

Snoring is a risk factor for hypertension independently of apnoea and anthropometric dimensions. While the presence of snoring is not able to replace a thorough polysomnographic evaluation of the apnoea-hypopnoea index and OSA, snoring as an acoustic signal is easily detectable. The early identification and management of snoring may reduce cardiovascular risk.

Review of and Updates on Hypertension in Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a prevalent sleep disorder as is hypertension (HTN) in the 21st century with the rising incidence of obesity. Numerous studies have shown a strong association of OSA with cardiovascular morbidity and mortality. There is overwhelming evidence supporting the relationship between OSA and hypertension (HTN). The pathophysiology of HTN in OSA is complex and dependent on various factors such as sympathetic tone, renin-angiotensin-aldosterone system, endothelial dysfunction, and altered baroreceptor reflexes. The treatment of OSA is multifactorial ranging from CPAP to oral appliances to lifestyle modifications to antihypertensive drugs. OSA and HTN both need prompt diagnosis and treatment to help address the growing cardiovascular morbidity and mortality due to these two entities.

Is Mania the Hypertension of the Mood? Discussion of A Hypothesis

Beyond both being biphasic/bidirectional disorders (hypo)mania and essential hypertension share a surprising number of similarities and an overlap between their genetics, biological background, underlying personality and temperamental factors, precipitating factors, comorbidity and response to treatment, indicating a possibly partially shared biological background. Based on theoretical knowledge, similarities related to characteristics, manifestation and course, and the results of pharmacological studies related to the effects and side effects of pharmacotherapies used in the treatment of these two distinct disorders, the authors outline a hypothesis discussing the similar origins of these two phenomena and thus mania being the hypertension of mood in memory of Athanasios Koukopoulos, one of the greatest researchers and theoreticists of mania of all time.

Patients with Obstructive Sleep Apnea Display Decreased Flow-Mediated Dilatation: Evidence from a Meta-Analysis

Background

Endothelial dysfunction, which can be measured by flow-mediated dilatation (FMD), is an early clinical marker of atherosclerosis, which is considered to be the main cause of the observed cardiovascular complications in obstructive sleep apnea (OSA) patients. The association between OSA and endothelial dysfunction has been reported in a number of studies; however, the findings are not entirely consistent. Our aim was to meta-analytically synthesize the existing evidence to explore the association between OSA and endothelial dysfunction.

Material/Methods

Data from PubMed, EMBASE, the Cochrane library, and Google Scholar for all trials that investigated the relationship between endothelial dysfunction and OSA were systematically reviewed. The minimum inclusion criteria for the studies were reporting of the Apnea-Hypopnea Index (AHI) and FMD measurements (as an indicator of endothelial dysfunction) for both OSA and control groups. Data from case-control studies that met the inclusion criteria were extracted.

Results

Twenty-eight studies comprising a total of 1496 OSA patients and 1135 controls were included in the meta-analysis. A random-effects model was used. The weighted mean difference in the FMD measurements was −3.07 and the 95% confidence interval was −3.71 to −2.43 (P<0.01). Meta-regression analysis showed that age, sex, body mass index (BMI), blood pressure, glucose, high-density lipoprotein (HDL) cholesterol, and low-density lipoprotein (LDL) cholesterol did not explain the heterogeneity.

Conclusions

This meta-analysis showed that patients with OSA have decreased FMD, which may contribute to the development of atherosclerosis.

Chronic intermittent hypoxia versus continuous hypoxia: Same effects on hemorheology?

Although both chronic intermittent hypoxia (CIH) and chronic continuous hypoxia (CCH) have effects on hemorheology, we do not know whether their roles are the same. In this study, we explored the effect of simulated-apnea CIH on hemorheology in experimental rats and compared with the effect of CCH. 45 adult SD rats were randomly divided into the normoxic control group, CCH and CIH groups. CIH rats were given nitrogen and air alternately for 8 hours per day and the experiment lasted for 5 weeks. The control group were placed in the normoxia animal chambers, and the CCH rats were housed in the same chambers which were continuously given normobaric hypoxia (FiO2 = 10%). After the preparations, the blood samples were taken and the hemorheology were determined. Compared with control group, the whole blood apparent viscosity, plasma viscosity, hematocrit, erythrocyte aggregation index and electrophoresis index, platelet aggregation rate and fibrinogen significantly increased in CIH group and CCH group. The whole blood viscosity, plasma viscosity, hematocrit and fibrinogen values were much higher in CCH group than in CIH group. However, there was not significantly difference in RBC deformation index or rigidity index among the three groups and no significantly differences were found in the effects on RBC rheological property between CIH and CCH. Our results suggest that intermittent hypoxia and continuous hypoxia increase whole blood viscosity, impair the functions of red blood cells and promote the platelet aggregation in model rats. Moreover, CCH had a greater effect on blood rheology than CIH.

Validation of the Behavioral Risk Factor Surveillance System Sleep Questions

STUDY OBJECTIVES

leep problems may constitute a risk for health problems, including cardiovascular disease, depression, diabetes, poor work performance, and motor vehicle accidents. The primary purpose of this study was to assess the validity of the current Behavioral Risk Factor Surveillance System (BRFSS) sleep questions by establishing the sensitivity and specificity for detection of sleep/ wake disturbance.

METHODS

Repeated cross-sectional assessment of 300 community dwelling adults over the age of 18 who did not wear CPAP or oxygen during sleep. Reliability and validity testing of the BRFSS sleep questions was performed comparing to BFRSS responses to data from home sleep study, actigraphy for 14 days, Insomnia Severity Index, Epworth Sleepiness Scale, and PROMIS-57.

RESULTS

Only two of the five BRFSS sleep questions were found valid and reliable in determining total sleep time and excessive daytime sleepiness.

CONCLUSIONS

Refinement of the BRFSS questions is recommended.

Interaction between Obstructive Sleep Apnea and Shortened Telomere Length on Brain White Matter Abnormality

STUDY OBJECTIVES

Age-related brain white matter changes (WMC) have been associated separately with obstructive sleep apnea (OSA) and short telomere length (TL). No studies have examined their interaction effect on WMC.

METHODS

This is a cross-sectional study with a community-based sample of 420 participants (mean age, 61.3 ± 7.2) from the Korean Genome and Epidemiology Study during 2011-2012. An overnight fasted blood sample was taken to determine glucose and blood lipid levels at the sleep laboratory of Korea University Ansan Hospital. The status of brain WMC was determined using structural magnetic resonance imaging at 1.5 Tesla. Overnight polysomnography was performed, and leukocyte TL was measured. OSA was determined based on apnea-hypopnea index, and short TL was defined as the lowest quartile of the study participants.

RESULTS

Adjusting for age, sex, BMI, smoking, drinking, snoring, and hypertension, odds ratio (OR) of brain WMC was estimated using multivariate logistic regression. The odds ratio was significant for cardiovascular disease (OR, 4.5; 95% CI, 1.2-16.3) and OSA (OR, 4.0; 95% CI, 1.0-15.2) among those with short TL; and for diabetes (OR, 3.0; 95% CI, 1.3-13.0) and age (OR, 1.1; 95% CI, 1.0-1.1) among those with longer TL. Interaction effect of OSA and short TL (OR, 4.3; 95% CI, 1.4-13.8) was significant, compared to those with neither OSA nor short TL.

CONCLUSIONS

This study provides a first evidence of mediated interaction of short TL with OSA on brain WMC in a community-based sample. The results generate new hypotheses regarding mechanisms of impaired brain health in sleep apnea.

Meta-analysis of effects of obstructive sleep apnea on the renin-angiotensin-aldosterone system

Background

Obstructive sleep apnea (OSA) is the most common cause of resistant hypertension, which has been proposed to result from activation of the renin–angiotensin–aldosterone system (RAAS). We meta-analyzed the effects of OSA on plasma levels of RAAS components.

Methods

Full-text studies published on MEDLINE and EMBASE analyzing fasting plasma levels of at least one RAAS component in adults with OSA with or without hypertension. OSA was diagnosed as an apnea-hypopnea index or respiratory disturbance index ≥ 5. Study quality was evaluated using the Newcastle-Ottawa Scale, and heterogeneity was assessed using the I² statistic. Results from individual studies were synthesized using inverse variance and pooled using a random-effects model. Subgroup analysis, sensitivity analysis, and meta-regression were performed, and risk of publication bias was assessed.

Results

The meta-analysis included 13 studies, of which 10 reported results on renin (n = 470 cases and controls), 7 on angiotensin II (AngII, n = 384), and 9 on aldosterone (n = 439). AngII levels were significantly higher in OSA than in controls [mean differences = 3.39 ng/L, 95% CI: 2.00–4.79, P < 0.00001], while aldosterone levels were significantly higher in OSA with hypertension than OSA but not with hypertension (mean differences = 1.32 ng/dL, 95% CI: 0.58–2.07, P = 0.0005). Meta-analysis of all studies suggested no significant differences in aldosterone between OSA and controls, but a significant pooled mean difference of 1.35 ng/mL (95% CI: 0.88–1.82, P < 0.00001) emerged after excluding one small-sample study. No significant risk of publication bias was detected among all included studies.

Conclusions

OSA is associated with higher AngII and aldosterone levels, especially in hypertensive patients. OSA may cause hypertension, at least in part, by stimulating RAAS activity.