Obstructive sleep apnoea syndrome as a risk factor for hypertension: population study

Epigenetic changes by DNA methylation in chronic and intermittent hypoxia

DNA methylation of cytosine residues is a well-studied epigenetic change, which regulates gene transcription by altering accessibility for transcription factors. Hypoxia is a pervasive stimulus that affects many physiological processes. The circulatory and respiratory systems adapt to chronic sustained hypoxia, such as that encountered during a high-altitude sojourn. Many people living at sea level experience chronic intermittent hypoxia (IH) due to sleep apnea, which leads to cardiovascular and respiratory maladaptation. This article presents a brief update on emerging evidence suggesting that changes in DNA methylation contribute to pathologies caused by chronic IH and potentially mediate adaptations to chronic sustained hypoxia by affecting the hypoxia-inducible factor (HIF) signaling pathway.

Effects of continuous positive airway pressure on blood pressure in patients with resistant hypertension and obstructive sleep apnea: a systematic review and meta-analysis of six randomized controlled trials

OBJECTIVE

To evaluate systematically the effects of continuous positive airway pressure (CPAP) on blood pressure in patients with resistant hypertension and obstructive sleep apnea (OSA).

METHODS

The Cochrane Library, PubMed, ScienceDirect, and the Web of Science were searched for studies investigating the effects of CPAP on blood pressure in patients with resistant hypertension and OSA. The selected studies underwent quality assessment and meta-analysis, as well as being tested for heterogeneity.

RESULTS

Six randomized controlled trials were included in the meta-analysis. The pooled estimates of the changes in mean systolic blood pressure and mean diastolic blood pressure (as assessed by 24-h ambulatory blood pressure monitoring) were -5.40 mmHg (95% CI: -9.17 to -1.64; p = 0.001; I2 = 74%) and -3.86 mmHg (95% CI: -6.41 to -1.30; p = 0.00001; I2 = 79%), respectively.

CONCLUSIONS

CPAP therapy can significantly reduce blood pressure in patients with resistant hypertension and OSA.

The long-term effects of mandibular advancement splint on cardiovascular fitness and psychomotor performance in patients with mild to moderate obstructive sleep apnea: a prospective study

BACKGROUND

Obstructive sleep apnea (OSA) manifests as a reduction or complete cessation of airflow despite an ongoing inspiratory effort, leading to hypoxemia and hypercapnia. The inability to maintain normal breathing reduces the oxygen saturation in blood leading to a cycle of various systemic implications. Hence, a prospective single arm study was planned to evaluate the long-term (2 years) effect of oral appliance on cardiovascular fitness and psychomotor performance in patients with mild to moderate obstructive sleep apnea.

METHODS

Thirty dentulous OSA patients (25 males; 5 females; age 41 ± 4 years; BMI 22 ± 5; AHI 5-30) were included in the study. All the patients were assessed for systolic blood pressure (SBP), diastolic blood pressure (DBP), apnea/hypopnea index (AHI), lipid peroxidation, and psychomotor vigilance test at baseline, 6 months, 1 year, and 2 years after wearing mandibular advancement splint (MAS).

RESULTS

A significant reduction in AHI, blood pressure, and lipid peroxidation was observed following MAS use. Psychomotor vigilance test showed marked improvement in response time with almost 0 count of lapses after 2 years of MAS use.

CONCLUSIONS

The present study suggested that MAS can be helpful in improving cardiovascular fitness and cognitive response in patients with mild to moderate OSA.

A cross-sectional survey of the nature and correlates of sleep disturbance in people with psoriasis

BACKGROUND

Research suggests that sleep disturbance is common in psoriasis. While several sleep investigations have been conducted in psoriasis populations, many have methodological shortcomings, and no study has examined multiple dimensions of sleep-wake functioning. Moreover, research has yet to be performed comprehensively examining the range of physical and psychological factors that may affect sleep in people with psoriasis.

OBJECTIVES

To characterize sleep disturbance using validated measures and to identify physical and psychological predictors of sleep quality in people with psoriasis.

METHODS

An online survey was conducted (186 respondents; mean age 39·2 years) comprising validated measures assessing sleep [Pittsburgh Sleep; Quality Index (PSQI), Berlin Questionnaire, Pre-Sleep Arousal Scale]; chronotype (Morningness-Eveningness Questionnaire); mood (Hospital Anxiety and Depression Scale); itch (5-D Itch Scale); and psoriasis severity (Simplified Psoriasis Index). Group comparisons and regression analyses were used to examine predictors of poor sleep.

RESULTS

The mean PSQI score was 9·2 ± 4·3, with 76·3% scoring above the threshold for poor sleep (≥ 6 on the PSQI) and 32·5% scoring 'positive' for probable obstructive sleep apnoea (OSA). Poor sleep and high likelihood of OSA were associated with more severe psoriasis (P < 0·05; η = 0·07; η² = 0·005). Cognitive arousal (β = 0·26, P = 0·001), itch (β = 0·26, P < 0·001) and depression (β = 0·24, P = 0·001) were the most robust predictors of poor sleep quality, which, together with somatic arousal (β = 0·17, P = 0·022), accounted for 43% of variance in PSQI scores.

CONCLUSIONS

Poor sleep is common in psoriasis and associated with psychological and physical factors. Rates of probable OSA are also high. Given the importance of restorative sleep for health, sleep complaints should receive greater clinical attention in the management of psoriasis.

Impact of obstructive sleep apnoea and intermittent hypoxia on cardiovascular and cerebrovascular regulation

NEW FINDINGS

What is the topic of this review? This review examines the notion that obstructive sleep apnoea (OSA) and intermittent hypoxia (IH) have hormetic effects on vascular health. What advances does it highlight? Clinical (OSA patient) and experimental animal and human models report that IH is detrimental to vascular regulation. However, mild IH and, by extension, mild OSA also have physiological and clinical benefits. This review highlights clinical and experimental animal and human data linking OSA and IH to vascular disease and discusses how hormetic effects of OSA and IH relate to OSA severity, IH intensity and duration, and patient/subject age. Obstructive sleep apnoea (OSA) is associated with increased risk of cardiovascular and cerebrovascular disease, a consequence attributed in part to chronic intermittent hypoxia (IH) resulting from repetitive apnoeas during sleep. Although findings from experimental animal, and human, models have shown that IH is detrimental to vascular regulation, the severity of IH used in many of these animal studies [e.g. inspired fraction of oxygen (FI,O2) = 2-3%; oxygen desaturation index = 120 events h^-1 ] is considerably greater than that observed in the majority of patients with OSA. This may also explain disparities between animal and recently developed human models of IH, where IH severity is, by necessity, less severe (e.g. FI,O2 = 10-12%; oxygen desaturation index = 15-30 events h^-1 ). In this review, we highlight the current knowledge regarding the impact of OSA and IH on cardiovascular and cerebrovascular regulation. In addition, we critically discuss the recent notion that OSA and IH may have hormetic effects on vascular health depending on conditions such as OSA severity, IH intensity and duration, and age. In general, data support an independent causal link between OSA and vascular disease, particularly for patients with severe OSA. However, the data are equivocal for older OSA patients and patients with mild OSA, because advanced age and short-duration, low-intensity IH have been reported to provide a degree of protection against IH and ischaemic events such as myocardial infarction and stroke, respectively. Overall, additional studies are needed to investigate the beneficial/detrimental effects of mild OSA on the various vascular beds.

An Official American Thoracic Society Research Statement: Impact of Mild Obstructive Sleep Apnea in Adults

BACKGROUND

Mild obstructive sleep apnea (OSA) is a highly prevalent disorder in adults; however, whether mild OSA has significant neurocognitive and cardiovascular complications is uncertain.

OBJECTIVES

The specific goals of this Research Statement are to appraise the evidence regarding whether long-term adverse neurocognitive and cardiovascular outcomes are attributable to mild OSA in adults, evaluate whether or not treatment of mild OSA is effective at preventing or reducing these adverse neurocognitive and cardiovascular outcomes, delineate the key research gaps, and provide direction for future research agendas.

METHODS

Literature searches from multiple reference databases were performed using medical subject headings and text words for OSA in adults as well as by hand searches. Pragmatic systematic reviews of the relevant body of evidence were performed.

RESULTS

Studies were incongruent in their definitions of "mild" OSA. Data were inconsistent regarding the relationship between mild OSA and daytime sleepiness. However, treatment of mild OSA may improve sleepiness in patients who are sleepy at baseline and improve quality of life. There is limited or inconsistent evidence pertaining to the impact of therapy of mild OSA on neurocognition, mood, vehicle accidents, cardiovascular events, stroke, and arrhythmias.

CONCLUSIONS

There is evidence that treatment of mild OSA in individuals who demonstrate subjective sleepiness may be beneficial. Treatment may also improve quality of life. Future research agendas should focus on clarifying the effect of mild OSA and impact of effective treatment on other neurocognitive and cardiovascular endpoints as detailed in the document.

Peri-apneic hemodynamic reactions in obstructive sleep apnea

Obstructive sleep apnea (OSA) increases cardiovascular morbidity and mortality. Little is known on acute peri-apneic hemodynamic alterations due to apneas. We assessed these rapid changes and how duration of apnea might contribute to them. Eight patients with severe OSA were studied with polysomnography including continuous blood pressure monitoring. Peri-apneic hemodynamic alterations, heart rate, blood pressure, stroke volume, cardiac output and peripheral resistance, were assessed in short (<20s) and long (>27s) apneas. Systolic and diastolic blood pressure along with heart rate elevated significantly in both apneas. These changes occurred within first 10 beats immediately after apnea. In contrast to short apneas long apneas caused sudden increase of 0.7l in cardiac output. Acute and pronounced peri-apneic hemodynamic alterations were seen during both short and long apneas. These described rapid hemodynamic changes might escape autoregulatory mechanisms of several organs, thus making OSA patients vulnerable to acute cardiovascular events.

Recognition and treatment of sleep-disordered breathing: an important component of chronic disease management

Sleep-disordered breathing (SDB) is a highly prevalent condition, and is associated with many debilitating chronic diseases. The role of untreated obstructive sleep apnea (OSA) in arterial hypertension has been recognized in international guidelines. Treatment with continuous positive airway pressure (CPAP) is associated with clinically-relevant reductions in blood pressure. In heart failure (HF), SDB is associated with worse prognosis and increased mortality. Major HF guidelines recommend that patients should be treated for sleep apnea to improve their HF status. Severe OSA increases the risk of arrhythmias, including atrial fibrillation, influences risk management in stroke, and is highly prevalent in patients with type 2 diabetes. Effective treatment with CPAP improves the success of antiarrhythmic interventions, improves outcomes in stroke and reduces hyperglycemia in diabetes. Patients with coronary artery disease also have a high prevalence of SDB, which is independently associated with worse outcomes. The role of CPAP for secondary cardiovascular prevention remains to be determined. Data from large, well-conducted clinical trials have shown that noninvasive ventilation, targeted to markedly reduce hypercapnia, significantly improves survival and reduces readmission in stable hypercapnic chronic obstructive pulmonary disease. The association of SDB with chronic diseases contributes to the high healthcare costs incurred by SDB patients. SDB also has an important negative impact on quality of life, which is reversed by CPAP treatment. The high prevalence of SDB, and its association with diseases that cause significant morbidity and mortality, suggest that the diagnosis and management of SDB is an important therapeutic goal. First, adherent CPAP treatment significantly improves the quality of life of all patients with SDB; second, it eliminates the negative impact of untreated SDB on any associated chronic diseases; and third, it significantly reduces the increased costs of all hospital and medical services directly associated with untreated SDB. In short, the recognition and treatment of SDB is vital for the continued health and wellbeing of individual patients with SDB.

Subclinical sleep apnoea and plasma levels of endothelin-1 among young and healthy adults

Objective

Obstructive sleep apnoea (OSA) is a risk factor for vascular disease and other adverse outcomes. These associations may be at least partly due to early endothelin-1 (ET-1)-mediated endothelial dysfunction (ED). Therefore, we assessed the relationships between subclinical sleep apnoea and plasma levels of ET-1.

Methods

We performed a population-based study among 1255 young and healthy adults aged 25–41 years. Cardiovascular disease, diabetes or a body mass index >35 kg/m² were exclusion criteria. Plasma levels of ET-1 were measured using a high-sensitivity, single-molecule counting technology. The relationships between subclinical sleep apnoea (OSA indices: respiratory event index (REI), oxygen desaturation index (ODI), mean night-time blood oxygen saturation (SpO₂)) and ET-1 levels were assessed by multivariable linear regression analysis.

Results

Median age of the cohort was 35 years. Median ET-1 levels were 2.9 (IQR 2.4–3.6) and 2.5 pg/mL (IQR 2.1–3.0) among patients with (n=105; 8%) and without subclinical sleep apnoea (REI 5–14), respectively. After multivariable adjustment, subclinical sleep apnoea remained significantly associated with plasma levels of ET-1 (β=0.13 (95% CI 0.06 to 0.20) p=0.0002 for a REI 5–14; β=0.10 (95% CI 0.03 to 0.16) p=0.003 for an ODI≥5). Every 1% decrease in mean night-time SpO₂ increased ET-1 levels by 0.1 pg/mL, an association that remained significant after multivariable adjustment (β=0.02 (95% CI 0.003 to 0.033) p=0.02).

Conclusions

In this study of young and healthy adults, we found that participants with subclinical sleep apnoea had elevated plasma ET-1 levels, an association that was due to night-time hypoxaemia. Our results suggest that ED may already be an important consequence of subclinical sleep apnoea.

Secondary hypertension in adults

Secondary hypertension occurs in a significant proportion of adult patients (~10%). In young patients, renal causes (glomerulonephritis) and coarctation of the aorta should be considered. In older patients, primary aldosteronism, obstructive sleep apnoea and renal artery stenosis are more prevalent than previously thought. Primary aldosteronism can be screened by taking morning aldosterone and renin levels, and should be considered in patients with severe, resistant or hypokalaemia-associated hypertension. Symptoms of obstructive sleep apnoea should be sought. Worsening of renal function after starting an angiotensin-converting enzyme inhibitor suggests the possibility of renal artery stenosis. Recognition, diagnosis and treatment of secondary causes of hypertension lead to good clinical outcomes and the possible reversal of end-organ damage, in addition to blood pressure control. As most patients with hypertension are managed at the primary care level, it is important for primary care physicians to recognise these conditions and refer patients appropriately.

Ambulatory Blood Pressure Monitoring in Chinese Patients with Obstructive Sleep Apnea

STUDY OBJECTIVES

Nocturnal blood pressure (BP) dipping in patients with obstructive sleep apnea (OSA) has not yet been well investigated in Chinese patients, in whom the relationship of OSA and body mass index (BMI) is weaker than that in Caucasians. The aim of this study was to evaluate the BP profile, and the relationships between nocturnal BP and the severity of OSA, in Chinese patients.

METHODS

Consecutive Chinese adult outpatients with suspected OSA had overnight polysomnography (PSG), office BP, and 24-h ambulatory BP monitoring (ABPM). The apnea-hypopnea index (AHI) and nocturnal oxygen saturation level were recorded, and BP patterns were classified based on the ABPM.

RESULTS

Fifty-six subjects (40 male and 16 female, 48.59 ± 13.27 y) were evaluated. There were 14 patients with mild OSA (25.0%, AHI: 10.56 ± 3.42 events/h), 16 with moderate OSA (28.6%, AHI: 23.536 ± 3.42 events/h) and 26 with severe OSA (46.4%, AHI: 51.52 ± 3.42 events/h). There were 18 dippers (32.1%), 27 non-dippers (48.2%), and 11 reverse dippers (19.6%). As OSA severity increased, non-dipping also increased. A total of 67.9% of the OSA patients showed overall hypertension on ABPM, 57.1% had daytime hypertension only, and 73.2% had nighttime hypertension.

CONCLUSIONS

OSA severity is associated with 24-h BP profiles in a population with only mild increases in BMI. These results can influence clinical practice, OSA management, and hypertension treatment policies.

Obstructive Sleep Apnea: Epidemiology and Portuguese patients profile

INTRODUCTION

Obstructive Sleep Apnea (OSA) is characterized by recurrent episodes of apnea and hypopnea, secondary to collapse of the upper airways during sleep. OSA is frequently associated to cardiovascular complications. In Portugal, its magnitude is unknown.

METHODS

In 2014 a cross-sectional study was performed using the Portuguese General Practitioner (GP) Sentinel Network (Rede Médicos Sentinela). Participants GP reported all OSA cases diagnosed and registered in their lists of users on the 31 December 2013. Frequency of OSA has been estimated by sex and age. OSA patients were also characterized by method of diagnosis, treatment, and underlying conditions. Association between risk factors and severe OSA (odds ratio) was calculated using a logistic regression model adjusting confounding.

RESULTS

Prevalence of OSA on the population aged 25 years or more was 0.89% (95 CI: 0.80-1.00%); it was higher in males 1.47% (95 CI: 1.30-1.67%) and in those aged between 65 and 74 (2.35%). Most had severe OSA (48.4%). Hypertension (75.9%), obesity (74.2%) and diabetes mellitus (34.1%) were the most frequent comorbidities. Being a male (OR: 2.6; 95 CI: 1.2-5.8) and having obesity (OR: 4.0; 95 CI: 1.8-8.6) were associated with an increased risk of severe OSA.

CONCLUSION

Found frequency of OSA was lower than other countries estimates, which may be explained by differences on case definition but can also suggest underdiagnosis of this condition as reported by other authors.

Ready-Made Versus Custom-Made Mandibular Repositioning Devices in Sleep Apnea: A Randomized Clinical Trial

STUDY OBJECTIVES

To compare the effectiveness of a custom-made (MRDc) versus ready-made (MRDr) mandibular repositioning devices (MRD) in the management of obstructive sleep apnea (OSA).

METHODS

A randomized crossover trial design was adopted in which patients with a confirmed diagnosis of OSA were randomly allocated to receive either a 3-month period of ready-made or custom-made MRD, with an intervening washout period of 2 weeks, prior to crossover. Treatment outcomes included both objective sleep monitoring and patient-centered measures (daytime sleepiness, partner snoring and quality of life).

RESULTS

Twenty-five patients, with a mild degree of OSA (apnea-hypopnea index of 13.3 [10.9-25] events/h) and daytime sleepiness (Epworth Sleepiness Scale of 11 [6-16]), completed both arms of the trial. The MRDc achieved a complete treatment response in 64% of participants, compared with 24% with the MRDr (p < 0.001). A significant difference was observed in treatment failures, when comparing the MRDr (36%) with the MRDc (4%). Excessive daytime sleepiness (Epworth Sleepiness Scale ≥ 10) persisted in 33% (MRDc) and 66% (MRDr) of OSA subjects, following treatment. A statistically significant improvement was observed in quality of life scales following MRDc therapy only. Significant differences were observed in relation to both the number of nights per week (p = 0.004) and hours per night (p = 0.006) between the two different designs of device.

CONCLUSIONS

The study demonstrates the significant clinical effectiveness of a custom-made mandibular repositioning device, particularly in terms of patient compliance and tolerance, in the treatment of OSA.

Angiotensin-(1-7) relieved renal injury induced by chronic intermittent hypoxia in rats by reducing inflammation, oxidative stress and fibrosis

We aimed to study the renal injury and hypertension induced by chronic intermittent hypoxia (CIH) and the protective effects mediated by angiotensin 1-7 [Ang(1-7)]. We randomly assigned 32 male Sprague-Dawley rats (body weight 180-200 g) to normoxia control, CIH, Ang(1-7)-treated normoxia, and Ang(1-7)-treated CIH groups. Systolic blood pressure (SBP) was monitored at the start and end of each week. Renal sympathetic nerve activity (RSNA) was recorded. CTGF and TGF-β were detected by immunohistochemistry and western blotting. Tissue parameters of oxidative stress were also determined. In addition, renal levels of interleukin-6, tumor necrosis factor-α, nitrotyrosine, and hypoxia-inducible factor-1α were determined by immunohistochemistry, immunoblotting, and ELISA. TUNEL assay results and cleaved caspase 3 and 12 were also determined. Ang(1-7) induced a reduction in SBP together with a restoration of RSNA in the rat model of CIH. Ang(1-7) treatment also suppressed the production of reactive oxygen species, reduced renal tissue inflammation, ameliorated mesangial expansion, and decreased renal fibrosis. Thus, Ang(1-7) treatment exerted renoprotective effects on CIH-induced renal injury and was associated with a reduction of oxidative stress, inflammation and fibrosis. Ang(1-7) might therefore represent a promising therapy for obstructive sleep apnea-related hypertension and renal injury.

Sleep apnea in total joint arthroplasty patients and the role for cardiac biomarkers for risk stratification: an exploration of feasibility

Obstructive sleep apnea (OSA) is highly prevalent in patients undergoing total joint arthroplasty (TJA) and is a major risk factor for postoperative cardiovascular complications and death. Recognizing this, the American Society of Anesthesiologists urges clinicians to implement special considerations in the perioperative care of OSA patients. However, as the volume of patients presenting for TJA increases, resources to implement these recommendations are limited. This necessitates mechanisms to efficiently risk stratify patients having OSA who may be susceptible to post-TJA cardiovascular complications. We explore the role of perioperative measurement of cardiac troponins (cTns) and brain natriuretic peptides (BNPs) in helping determine which OSA patients are at increased risk for post-TJA cardiovascular-related morbidity.

Changes to a pediatric sleep disordered breathing clinic improve wait-times and clinic efficiency

BACKGROUND

Recognition of the impact of sleep disordered breathing (SDB) on health has increased referrals in pediatric respiratory medicine with a concomitant increase in wait-times.

METHODS

To reduce wait-time (primary outcome), we developed a rapid SDB clinic (RSC) to identify, diagnose, and treat patients with few to no comorbidities (uncomplicated) and presumed SDB based on the referral letter. The RSC uses 1) parent-report questionnaires to capture the patients' medical history and 2) sleep testing (e.g., overnight oximetry) completed prior to the initial consultation.

RESULTS

The combination of pre-clinic electronic-questionnaires and testing increased patient consult capacity by 100%. Of the 256 patients referred to the RSC over 28 months, 130 patients were seen through the RSC, 17 patients were re-triaged to a standard sleep clinic (SSC) after questionnaire review, 51 patients were completing the RSC process, and 75 patients had their referral cancelled. An electronic-questionnaire RSC (n = 45) reduced wait-times by 34% to 142.8 (SD 57) days compared to a paper-questionnaire RSC (P < 0.001). The electronic RSC was also associated with 77.4 (SD 74.1) days reduction in wait-time (P = 0.04) for SSC patients seen during the same timeframe. RSC patients were 75% less likely to require a follow-up visit (P < 0.001) compared to SSC patients seen during the same timeframe.

CONCLUSION

A targeted, streamlined clinic using electronic-questionnaires for uncomplicated patients can improve wait-times for children being referred to pediatric respiratory medicine for evaluation of sleep disordered breathing. Pediatr Pulmonol. 2016;51:1234-1241. © 2016 Wiley Periodicals, Inc.

A Narrative Review of How Sleep-Related Breathing Disorders and Cardiovascular Diseases Are Linked: An Update for Advanced Practice Registered Nurses

PURPOSE/OBJECTIVES

Sleep-related breathing disorders (SRBDs), including obstructive sleep apnea and central sleep apnea, are common among patients with cardiovascular disease (CVD), but clinicians often do not pay enough attention to SRBDs. The purpose of this narrative review is to update advanced practice registered nurses on the literature focusing on the relationship between SRBDs and CVD (eg, hypertension, heart failure, coronary artery disease, arrhythmias, and stroke) and on treatments that can improve SRBDs in patients with CVD.

DESCRIPTION OF THE PROJECT

We conducted an electronic search of the literature published between 1980 and 2016 from PubMed, Cumulative Index to Nursing and Allied Health Literature, Web of Science, Academic Search Premier, and related health resource Web sites to address the aims of this study.

OUTCOMES

Fifty-six primary research articles (42 observational studies and 14 experimental and quasi-experimental studies) were selected based on our study aims and inclusion criteria. The studies revealed that individuals with CVD are at a greater risk for SRBDs and that SRBDs can worsen CVD. The findings from the studies also suggest that positive airway treatment could improve both SRBDs and CVD.

CONCLUSIONS

This review found a close relationship between SRBDs and CVD. Advanced practice registered nurses are in key positions to identify and help patients manage SRBDs. In particular, advanced practice registered nurses can educate staff and establish standards of practice to improve outcomes for patients with CVD.

Epigenetic regulation of redox state mediates persistent cardiorespiratory abnormalities after long-term intermittent hypoxia

KEY POINTS

The effects of short-term (ST; 10 days) and long-term (LT; 30 days) intermittent hypoxia (IH) on blood pressure (BP), breathing and carotid body (CB) chemosensory reflex were examined in adult rats. ST- and LT-IH treated rats exhibited hypertension, irregular breathing with apnoea and augmented the CB chemosensory reflex, with all these responses becoming normalized during recovery from ST- but not from LT-IH. The persistent cardiorespiratory responses to LT-IH were associated with elevated reactive oxygen species (ROS) levels in the CB and adrenal medulla, which were a result of DNA methylation-dependent suppression of genes encoding anti-oxidant enzymes (AOEs). Treating rats with decitabine either during LT-IH or during recovery from LT-IH prevented DNA methylation of AOE genes, normalized the expression of AOE genes and ROS levels, reversed the heightened CB chemosensory reflex and hypertension, and also stabilized breathing.

ABSTRACT

Rodents exposed to chronic intermittent hypoxia (IH), simulating blood O₂ saturation profiles during obstructive sleep apnoea (OSA), have been shown to exhibit a heightened carotid body (CB) chemosensory reflex and hypertension. CB chemosensory reflex activation also results in unstable breathing with apnoeas. However, the effect of chronic IH on breathing is not known. In the present study, we examined the effects of chronic IH on breathing along with blood pressure (BP) and assessed whether the autonomic responses are normalized after recovery from chronic IH. Studies were performed on adult, male, Sprague-Dawley rats exposed to either short-term (ST; 10 days) or long-term (LT, 30 days) IH. Rats exposed to either ST- or LT-IH exhibited hypertension, irregular breathing with apnoeas, an augmented CB chemosensory reflex as indicated by elevated CB neural activity and plasma catecholamine levels, and elevated reactive oxygen species (ROS) levels in the CB and adrenal medulla (AM). All these effects were normalized after recovery from ST-IH but not from LT-IH. Analysis of the molecular mechanisms underlying the persistent effects of LT-IH revealed increased DNA methylation of genes encoding anti-oxidant enzymes (AOEs). Treatment with decitabine, a DNA methylation inhibitor, either during LT-IH or during recovery from LT-IH, prevented DNA methylation, normalized the expression of AOE genes, ROS levels, CB chemosensory reflex and BP, and also stabilized breathing. These results suggest that persistent cardiorespiratory abnormalities caused by LT-IH are mediated by epigenetic re-programming of the redox state in the CB chemosensory reflex pathway.

High prevalence of known and unknown pulmonary diseases in patients with claudication during exercise oximetry: A retrospective analysis

The prevalence of pulmonary disease in patients with peripheral artery disease (PAD) has not been extensively studied. Recent evidence has shown that ∼20% of the patients have an atypical chest transcutaneous oxygen pressure (TcpO2) pattern during exercise, which suggests walking-induced hypoxemia. The main objectives of this study were to: (1) describe in a retrospective way the characteristics of the patients suffering from claudication, who attended a treadmill testing in our laboratory, (2) assess the prevalence of known or unknown pulmonary disease. The second aim of this study was to evaluate the impact of the therapeutic interventions on the walking capacities, after treatment, of the eventually detected pulmonary disorders.We retrospectively analyzed 1482 exercise TcpO2 test results. Patients that had no history of pulmonary disease, but either reported severe dyspnea or showed atypical profiles on their chest exercise-TcpO2, were advised to refer to the department of pneumology for additional investigations.In addition to the 166 patients with a history of pulmonary disease, 158 patients were suspected of unknown pulmonary disease from the result of their TcpO2 test. Many patients (n = 99/158, 62.7%) did not attend a pulmonologist visit. A pulmonary disease was established in 55 (93.2%) of the other 59 patients. Obstructive sleep apnea syndrome (OSAS) was the one and only diagnosis retained in 42/59 patients (71.2%). Among the 47 patients who had a second evaluation of their walking capacity on treadmill, 38 had treatment of the pulmonary disease found, vascular surgery treatment or a severe restricted diet, 9 had no treatment. Only the "treated" group showed a significant improvement in the maximal walking distance on treadmill between the 2 evaluations, 313 ± 251 m to 433 ± 317 m (P = 0.03).This retrospective pilot study underlines the high prevalence of both known and unknown pulmonary disease in patients whose primary complaint was lower limb claudication. Systematic screening and treatment of pulmonary disease in patients with claudication might be justified, to improve walking ability of such patients and possibly reduce or delay the requirement for revascularization. Prospective studies are required to confirm these preliminary results.

Obstructive Sleep Apnea With Objective Daytime Sleepiness Is Associated With Hypertension

Subjective daytime sleepiness is considered a significant risk factor of hypertension in patients with obstructive sleep apnea (OSA). In this study, our goal was to examine the joint effect on hypertension of OSA and objective daytime sleepiness measured by the multiple sleep latency test (MSLT). A total of 1338 Chinese patients with OSA and 484 primary snorers were included in the study. All subjects underwent 1 night polysomnography followed by MSLT. The MSLT values were classified into 3 categories: >8 minutes, 5 to 8 minutes, and <5 minutes. Hypertension was defined based either on direct blood pressure measures or on diagnosis by a physician. After controlling for confounders, OSA combined with MSLT of 5 to 8 minutes increased the odds of hypertension by 95% (odds ratio, 1.95; 95% confidence interval, 1.10-3.46), whereas OSA combined with MSLT <5 minutes further increased the odds of hypertension by 111% (odds ratio, 2.11; 95% confidence interval, 1.22-3.31) compared with primary snorers with MSLT >8 minutes. In stratified analyses, the association of hypertension with MSLT in OSA patients was seen among both sexes, younger ages, both obese and nonobese patients, and patients with and without subjective excessive daytime sleepiness. We conclude that objective daytime sleepiness is associated with hypertension in patients with OSA.

Using Graduated in Vivo Exposure to Treat a Claustrophobic Response to Nasal Continuous Positive Airway Pressure

Continuous positive airway pressure (CPAP) is the preferred treatment for obstructive sleep apnea syndrome because it safely and effectively reduces or eliminates nighttime upper airway obstruction. Unfortunately, CPAP adherence rates are low(30% to 40%). For some patients, a history of trauma contributes to nonadherence by triggering a claustrophobic response to CPAP. Exposure is the treatment of choice for anxiety-based responses, such as claustrophobia. Here, we provide the first demonstration of the successful use of graduated in vivo exposure to treat an individual experiencing a trauma-related claustrophobic response to CPAP.

Effect of CPAP Withdrawal on BP in OSA: Data from Three Randomized Controlled Trials

BACKGROUND

Based on meta-analyses, the BP-lowering effect of CPAP therapy in patients with OSA is reported to be approximately 2 to 3 mm Hg. This figure is derived from heterogeneous trials, which are often limited by poor CPAP adherence, and thus the treatment effect may possibly be underestimated. We analyzed morning BP data from three randomized controlled CPAP withdrawal trials, which included only patients with optimal CPAP compliance.

METHODS

Within the three trials, 149 patients with OSA who were receiving CPAP were randomized to continue therapeutic CPAP (n = 65) or to withdraw CPAP (n = 84) for 2 weeks. Morning BP was measured at home before and after sleep studies in the hospital.

RESULTS

CPAP withdrawal was associated with a return of OSA (apnea-hypopnea index [AHI] at a baseline of 2.8/h and at follow-up of 33.2/h). Office systolic BP (SBP) increased in the CPAP withdrawal group compared with the CPAP continuation group by +5.4 mm Hg (95% CI, 1.8-8.9 mm Hg; P = .003) and in the home SBP group by +9.0 mm Hg (95% CI, 5.7-12.3 mm Hg; P < .001). Office diastolic BP (DBP) increased by +5.0 mm Hg (95% CI, 2.7-7.3 mm Hg; P < .001), and home DBP increased by +7.8 mm Hg (95% CI, 5.6-10.4 mm Hg; P < .001). AHI, baseline home SBP, use of statin drugs, sex, and the number of antihypertensive drugs prescribed were all independently associated with SBP change in multivariate analysis, controlling for age, BMI, smoking status, diabetes, and sleepiness.

CONCLUSIONS

CPAP withdrawal results in a clinically relevant increase in BP, which is considerably higher than in conventional CPAP trials; it is also underestimated when office BP is used. Greater OSA severity is associated with a higher BP rise in response to CPAP withdrawal.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT01332175 and NCT01797653) URL: www.clinicaltrials.gov and ISRCTN registry (ISRCTN 93153804) URL: http://www.isrctn.com/.

Daytime napping and increased risk of incident respiratory diseases: symptom, marker, or risk factor?

BACKGROUND

We have identified a strong association between daytime napping and increased mortality risk from respiratory diseases, but little is known about the relationship between daytime napping and respiratory morbidity.

METHODS

Data were drawn from the European Prospective Investigation into Cancer and Nutrition-Norfolk cohort. Participants reported napping habits during 1998-2000 and were followed up for respiratory disease hospital admissions until March 2009. Cox proportional hazards regression was used to examine the association between daytime napping and respiratory disease incidence risk.

RESULTS

The study sample included 10,978 men and women with a mean age of 61.9 years, and a total of 946 incident respiratory disease cases were recorded. After adjustment for age, sex, social class, education, marital status, employment status, nightshift work, body mass index, physical activity, smoking, alcohol intake, self-reported general health, hypnotic drug use, habitual sleep duration, and preexisting health conditions, daytime napping was associated with an increase in the overall respiratory disease incidence risk (hazard ratio (HR) = 1.32, 95% confidence interval (CI) 1.15, 1.52 for napping <1 h; HR = 1.54, 95% CI 1.14, 2.09 for napping ≥1 h). This association was more pronounced for lower respiratory diseases, especially for the risk of chronic lower respiratory diseases (HR = 1.52, 95% CI: 1.18, 1.96 for napping <1 h; HR = 1.72, 95% CI: 1.01, 2.92 for napping ≥1 h, overall p = 0.003).

CONCLUSIONS

Excessive daytime napping might be a useful marker of future respiratory disease incidence risk. Further studies are required to confirm these findings and help understand potential mechanisms.

Obstructive sleep apnea syndrome should be considered as a cause of nocturia in younger patients without other voiding symptoms

INTRODUCTION

This study aimed to evaluate urination frequency among patients with obstructive sleep apnea syndrome (OSAS) and the effect of continuous positive airway pressure (CPAP) treatment.

METHODS

We evaluated 138 men with moderate-to-severe OSAS by using polysomnography. Urination status was assessed at baseline and three months using the International Prostate Symptom Score and Overactive Bladder Symptom Score. Nocturia was defined as ≥2 nighttime urinations and patients were classified into Group A (<50 years old with nocturia), Group B (≥50 years old with nocturia), and Group C (patients without nocturia). OSAS severity and other urinary symptoms were also evaluated.

RESULTS

Patients with nocturia exhibited more severe OSAS, compared to patients without nocturia (apnea-hypopnea index [AHI]: 52.0 vs. 44.7; p=0.021). Group A had the worst AHI, but did not have additional voiding symptoms, compared to Group B (p<0.001). The number of urinations was significantly correlated with OSAS severity in <50-year-old patients (p=0.013). CPAP reduced the number of urinations in Group A (75% of patients) and Group B (90% of patients). Patients with and without improved nocturia exhibited significant differences in their baseline OSAS severity (AHI: 53.7 vs. 37.3; p=0.042).

CONCLUSIONS

OSAS severity was associated with the number of urinations in <50-year-old patients. CPAP decreased the nocturia frequency in 85% of patients with nocturia and was most effective in patients with severe AHI. However, additional studies should evaluate voiding volume in order to elucidate the mechanism of nocturia in patients with OSAS.

Obstructive Sleep Apnoea, Glucose Tolerance and Liver Steatosis in Obese Women

In this study of obstructive sleep apnoea (OSA), glucose tolerance and liver steatosis in females from an obesity unit, 45 patients (mean age 46.8 years, mean body mass index 39.4 kg/m2, all non-diabetic and alcohol abstainers) underwent nocturnal polysomnography, a 2 h oral glucose tolerance test and abdominal ultrasonography. OSA, defined as an apnoea–hypopnoea index (AHI) of ≤ 10 events/h, was present in 20 patients (44%). Impaired glucose tolerance (IGT) was found in eight patients (40%) with OSA and three patients (12%) without OSA; there was a positive linear relationship between AHI and post-load glucose levels. On multivariate logistic regression analysis, IGT was predicted by OSA independently of age, waist circumference, systolic blood pressure and current smoking. Liver steatosis was present in 37 women (82.2%), of whom six had grade III steatosis. Of the variables tested, IGT was the only predictor of grade III steatosis. In conclusion, OSA is an independent predictor of IGT which, in turn, is associated with severe liver steatosis in an obesity unit-based sample of women.

Blood Pressure Response to Losartan and Continuous Positive Airway Pressure in Hypertension and Obstructive Sleep Apnea

RATIONALE

Obstructive sleep apnea (OSA) is common in people with hypertension, particularly resistant hypertension. Treatment with an antihypertensive agent alone is often insufficient to control hypertension in patients with OSA.

OBJECTIVES

To determine whether continuous positive airway pressure (CPAP) added to treatment with an antihypertensive agent has an impact on blood pressure (BP) levels.

METHODS

During the initial 6-week, two-center, open, prospective, case-control, parallel-design study (2:1; OSA/no-OSA), all patients began treatment with an angiotensin II receptor antagonist, losartan, 50 mg daily. In the second 6-week, sex-stratified, open, randomized, parallel-design study of the OSA group, all subjects continued to receive losartan and were randomly assigned to either nightly CPAP as add-on therapy or no CPAP.

MEASUREMENTS AND MAIN RESULTS

Twenty-four-hour BP monitoring included assessment every 15 minutes during daytime hours and every 20 minutes during the night. Ninety-one patients with untreated hypertension underwent a home sleep study (55 were found to have OSA; 36 were not). Losartan significantly reduced systolic, diastolic, and mean arterial BP in both groups (without OSA: 12.6, 7.2, and 9.0 mm Hg; with OSA: 9.8, 5.7, and 6.1 mm Hg). Add-on CPAP treatment had no significant changes in 24-hour BP values but did reduce nighttime systolic BP by 4.7 mm Hg. All 24-hour BP values were reduced significantly in the 13 patients with OSA who used CPAP at least 4 hours per night.

CONCLUSIONS

Losartan reduced BP in OSA, but the reductions were less than in no-OSA. Add-on CPAP therapy resulted in no significant changes in 24-hour BP measures except in patients using CPAP efficiently. Clinical trial registered with www.clinicaltrials.gov (NCT00701428).​

The Role of Obesity in the Development of Left Ventricular Hypertrophy Among Children and Adolescents

Both obesity and hypertension have increased substantially among children over the last several decades. At the same time, mounting evidence has pointed to the role of these and other cardiovascular disease risk factors on the development of end organ damage such as left ventricular hypertrophy in children. While traditionally thought to occur in response to an increased afterload as in systemic hypertension, evidence demonstrates that obesity is associated with left ventricular hypertrophy independent of blood pressure. Both hemodynamic and non-hemodynamic factors contribute to the pathogenesis of obesity-related left ventricular remodeling. However, more contemporary research suggests that adiposity and blood pressure have a greater effect on left ventricular geometry when present together than when present alone. Normalization of left ventricular mass in obese hypertensive individuals requires achievement of both normotension and weight loss. Additional strategies are needed to promote the cardiovascular health of children, with greater emphasis placed on obesity prevention.

Obstructive Sleep Apnea Treatment and Atrial Fibrillation: A Need for Definitive Evidence

Prevalence rates of atrial fibrillation (AF) and obstructive sleep apnea (OSA) are rising on a global scale. Epidemiological data have consistently demonstrated an independent association between the 2 conditions. Investigators pose that pathophysiologic features of OSA enable progression of the AF substrate; these features include abnormalities of gas exchange, autonomic remodeling, atrial stretch, and inflammation. Furthermore, many of the mechanistic perturbations that impact the AF substrate in OSA can be substantially attenuated by effective treatment with continuous positive airway pressure (CPAP). Clear associations of OSA treatment and improved AF control have been observed across multiple clinical contexts. However, the precision and generalizability of these findings are unclear in view of the data's observational nature. Although risk factor management has emerged as a critical component of AF treatment, effective control of many AF risk factors can be challenging in the longer term. In view of the efficacy and sustainability of CPAP therapy, OSA raises its profile as a prime candidate for intervention. However, translation of this strategy to the broader framework for AF management requires robust data from randomized controlled trials.

Prevalence of Risk for Obstructive Sleep Apnea Syndrome and Association With Risk Factors in Primary Care

Background

Obstructive sleep apnea syndrome (OSAS) is a chronic, progressive disease with high morbidity and mortality. It is underdiagnosed, especially among women.

Objective

To study the prevalence of high risk for OSAS globally and for the Berlin Questionnaire (BQ) categories, and to evaluate the reliability of the BQ use in the population studied.

Methods

Observational, cross-sectional study with individuals from the Niterói Family Doctor Program, randomly selected, aged between 45 and 99 years. The visits occurred between August/2011 and December/2012. Variables associated with each BQ category and with high risk for OSAS (global) were included in logistic regression models (p < 0.05).

Results

Of the total (616), 403 individuals (65.4%) reported snoring. The prevalence of high risk for OSA was 42.4%, being 49.7% for category I, 10.2% for category II and 77.6% for category III.

Conclusion

BQ showed an acceptable reliability after excluding the questions Has anyone noticed that you stop breathing during your sleep? and Have you ever dozed off or fallen asleep while driving?. This should be tested in further studies with samples mostly comprised of women and low educational level individuals. Given the burden of OSAS-related diseases and risks, studies should be conducted to validate new tools and to adapt BQ to better screen OSAS.

Upper gastrointestinal bleeding as a risk factor for dialysis and all-cause mortality: a cohort study of chronic kidney disease patients in Taiwan

OBJECTIVE

Impaired renal function is associated with higher risk of upper gastrointestinal bleeding (UGIB) in patients with chronic kidney disease and not on dialysis (CKD-ND). It is unclear if UGIB increases risk of chronic dialysis. The aim of the study was to investigate risk of chronic dialysis in CKD-ND patients with UGIB.

SETTING

All CKD-ND stage 3-5 patients of a CKD programme in one hospital between 2003 and 2009 were enrolled and prospectively followed until September 2012.

PRIMARY AND SECONDARY OUTCOME MEASURES

Chronic dialysis (dialysis for more than 3 months) started and all-cause mortality. The risk of chronic dialysis was analysed using Cox proportional hazard regression with adjustments for age, gender and renal function, followed by competing-risks analysis.

RESULTS

We analysed 3126 CKD-ND patients with a mean age of 65±14 years for 2.8 years. Of 3126 patients, 387 (12.4%) patients developed UGIB, 989 (31.6%) patients started chronic dialysis and 197 (6.3%) patients died. UGIB increased all-cause mortality (adjusted HR (aHR): 1.51, 95% CI 1.07 to 2.13) and the risk of chronic dialysis (aHR; 1.29, 95% CI 1.11 to 1.50). The subdistribution HR (SHR) of UGIB for chronic dialysis (competing event: all-cause mortality) was 1.37 (95% CI 1.15 to 1.64) in competing-risks analysis with adjustments for age, renal function, gender, diabetes, haemoglobin, albumin and urine protein/creatinine ratio.

CONCLUSIONS

UGIB is associated with increased risk of chronic dialysis and all-cause mortality in patients with CKD-ND stages 3-5. This association is independent of age, gender, basal renal function, haemoglobin, albumin and urine protein levels.

Obstructive Sleep Apnea Syndrome is Associated with Metabolic Syndrome among Adolescents and Youth in Beijing: data from Beijing Child and Adolescent Metabolic Syndrome Study

Background:

Obstructive sleep apnea (OSA) syndrome has a negative impact on the health of millions of adolescents and youth. The aim of this study was to evaluate the associations of OSA syndrome with obesity and cardiometabolic risk factors among adolescents and youth at risk for metabolic syndrome (MS).

Methods:

A total of 558 subjects aged 14–28 years were recruited from the Beijing Child and Adolescent Metabolic Syndrome Study. Each underwent a 2-h oral glucose tolerance test (OGTT), echocardiography, and liver ultrasonography. Anthropometric measures, blood levels of glucose, lipids, and liver enzymes were assessed. Subjects with high or low risk for OSA were identified by Berlin Questionnaire (BQ).

Results:

Among the subjects in obesity, 33.7% of whom were likely to have OSA by BQ. Subjects with high risk for OSA had higher neck and waist circumference and fat mass percentage compared to those with low risk for OSA (P < 0.001). Moreover, significant differences in levels of lipids, glucose after OGTT, and liver enzymes, as well as echocardiographic parameters were found between the two groups with high or low risk for OSA (P < 0.05). The rates of nonalcoholic fatty liver disease (71.0% vs. 24.2%), MS (38.9% vs. 7.0%), and its components in high-risk group were significantly higher than in low-risk group.

Conclusions:

The prevalence of OSA by BQ was high in obese adolescents and youth. A high risk for OSA indicates a high cardiometabolic risk. Mechanisms mediating the observed associations require further investigation.

The Clinical Effect of Acupuncture in the Treatment of Obstructive Sleep Apnea: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Purpose. This study aims to determine the clinical efficacy of acupuncture therapy in the treatment of obstructive sleep apnea. Methods. A systematic literature search was conducted in five databases including PubMed, EMBASE, CENTRAL, Wanfang, and CNKI to identify randomized controlled trials (RCTs) on the effect of acupuncture therapy for obstructive sleep apnea. Meta-analysis was conducted using the RevMan version 5.3 software. Results. Six RCTs involving 362 subjects were included in our study. Compared with control groups, manual acupuncture (MA) was more effective in the improvement of apnea/hypopnea index (AHI), apnea index, hypopnea index, and mean SaO₂. Electroacupuncture (EA) was better in improving the AHI and apnea index when compared with control treatment, but no statistically significant differences in hypopnea index and mean SaO₂ were found. In the comparison of MA and nasal continuous positive airway pressure, the results favored MA in the improvement of AHI; there was no statistical difference in the improvement in mean SaO₂. No adverse events associated with acupuncture therapy were documented. Conclusion. Compared to control groups, both MA and EA were more effective in improving AHI and mean SaO₂. In addition, MA could further improve apnea index and hypopnea index compared to control.

Cumulative Hypoxemia During Sleep Predicts Vascular Endothelial Dysfunction in Patients With Sleep-Disordered Breathing

BACKGROUND

Sleep-disordered breathing (SDB) is associated with repeated intermittent hypoxemia, and it is known as one of the risk factors for cardiovascular diseases. Previous studies assessing the effects of frequency and depth of hypoxemia on cardiovascular diseases have shown conflicting results. The aim of the current study was to clarify what SDB-related parameters most predict endothelial dysfunction to better understand the pathogenesis of endothelial dysfunction in patients with SDB.

METHODS

We conducted polysomnography (PSG) and measured flow-mediated vasodilation response (%FMD) in 50 outpatients suspected of SDB. Evaluated indices included: apnea-hypopnea index (AHI), 3% oxygen desaturation index (3%ODI), averaged arterial oxygen saturation (averaged SpO2), lowest arterial oxygen saturation (lowest SpO2), ratio of arterial oxygen saturation <90% (

RESULTS

Significant differences were observed only in the TDS between the first and third (P = 0.03) and between the first and forth (P = 0.04) quartile groups, stratified by %FMD. The %FMD showed a significant relationship with TDS (β = -0.47, P = 0.001), even after adjusting for confounding factors (β = -0.33, P = 0.02). In contrast, AHI, 3%ODI, averaged SpO2, lowest SpO2, and

CONCLUSIONS

This study shows the validity of TDS in predicting endothelial damage in patients with SDB. Cumulative hypoxemia, rather than the frequency of hypoxemic events presented as AHI, may be a greater contributing factor in causing endothelial dysfunction. A simple index like TDS may be a useful and novel indicator of the influence of SDB on the vasculature.

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Key Words

• blood pressure
• cardiovascular diseases
• endothelial function
• hypertension
• hypoxemia
• sleep-disordered breathing.

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MESH Headings

• Adult
• Aged
• Biomarkers/blood
• Endothelium, Vascular/physiopathology
• Female
• Humans
• Hyperemia/physiopathology
• Hypoxia/blood
• Hypoxia/diagnosis
• Hypoxia/etiology
• Hypoxia/physiopathology
• Male
• Middle Aged
• Oximetry
• Oxygen/blood
• Polysomnography
• Predictive Value of Tests
• Respiration
• Risk Factors
• Sleep
• Sleep Apnea Syndromes/complications
• Sleep Apnea Syndromes/diagnosis
• Sleep Apnea Syndromes/physiopathology
• Vascular Diseases/diagnosis
• Vascular Diseases/etiology
• Vascular Diseases/physiopathology
• Vasodilation

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Affiliation(s)

Hiroyuki Sawatari Department of Health Sciences, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
Akiko Chishaki Department of Health Sciences, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
Mari Nishizaka Sleep Apnea Center, Kyushu University Hospital, Fukuoka, Japan; Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
Tomotake Tokunou Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
Sonomi Adachi Sleep Apnea Center, Kyushu University Hospital, Fukuoka, Japan; Center for Clinical and Translational Research, Kyushu University Hospital, Fukuoka, Japan
Chikara Yoshimura Sleep Apnea Center, Kyushu University Hospital, Fukuoka, Japan
Tomoko Ohkusa Kirameki Projects Career Support Center, Kyushu University Hospital, Fukuoka, Japan
Shin-ichi Ando Sleep Apnea Center, Kyushu University Hospital, Fukuoka, Japan;

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Influence of obstructive sleep apnea on ischemia-modified albumin levels and carotid intima-media thickness

Obstructive sleep apnea (OSA) is associated with an increased risk of atherosclerosis. Carotid intima-media thickness (CIMT) is strongly associated with the presence of significant risk factors for cardiovascular disturbances. A disturbance in the oxidative/antioxidative balance is involved in the pathogenesis of OSA and cardiovascular diseases. Ischemia-modified albumin (IMA) is suggested as a novel marker of oxidative stress; IMA can be defined as decreased binding of transitional metal ions to serum albumin in oxidative status. The purpose of this research was to evaluate the influence of OSA on IMA levels and CIMT. In total, 61 individuals with OSA with no comorbidities and 24 healthy controls with a similar body mass index and age were enrolled in this study. Serum levels of IMA, CIMT (estimated radiologically), and polysomnographic parameters, were determined and interpreted. Serum IMA levels were significantly higher in individuals with OSA compared with the control group (p=0.0003). CIMT was significantly higher in the OSA group compared with the control group (0.88± 0.26 mm vs 0.75±0.17 mm, p=0.005). The CIMT and serum IMA levels were positively correlated with the apnea-hypopnea index (r=0.35 and r=0.32, respectively), and with the oxygen desaturation index (r=0.34 and r=0.29, respectively) at baseline. Increased IMA levels and CIMT may be related to increased oxidative stress and risk of atherosclerosis in individuals with OSA.

Comorbidities Associated with Obstructive Sleep Apnea: a Retrospective Study

Introduction Obstructive sleep apnea (OSA) is characterized by partial or complete recurrent upper airway obstruction during sleep. OSA brings many adverse consequences, such as hypertension, obesity, diabetes mellitus, cardiac and encephalic alterations, behavioral, among others, resulting in a significant source of public health care by generating a high financial and social impact. The importance of this assessment proves to be useful, because the incidence of patients with comorbidities associated with AOS has been increasing consistently and presents significant influence in natural disease history.

Objective The objective of this study is to assess major comorbidities associated with obstructive sleep apnea (OSA) and prevalence in a group of patients diagnosed clinically and polysomnographically with OSA.

Methods This is a retrospective study of 100 charts from patients previously diagnosed with OSA in our service between October 2010 and January 2013.

Results We evaluated 100 patients with OSA (84 men and 16 women) with a mean age of 50.05 years (range 19–75 years). The prevalence of comorbidities were hypertension (39%), obesity (34%), depression (19%), gastroesophageal reflux disease (GERD) (18%), diabetes mellitus (15%), hypercholesterolemia (10%), asthma (4%), and no comorbidities (33%). Comorbidities occurred in 56.2% patients diagnosed with mild OSA, 67.6% with moderate OSA, and 70% of patients with severe OSA.

Conclusion According to the current literature data and the values obtained in our paper, we can correlate through expressive values obesity with OSA and their apnea hypopnea index (AHI) values. However, despite significant prevalence of OSA with other comorbidities, our study could not render expressive significance values able to justify their correlations.

Obstructive sleep apnoea: patients' experiences of oral appliance treatment

Over the past few decades, there has been a pronounced increase in the number of patients being treated by general dental practitioners for obstructive sleep apnoea (OSA). The purpose of this study was to survey the care and patient experiences and the self-reported effectiveness of OSA treatment with an oral appliance (OA) incorporating mandibular advancement. The design was a retrospective, cross-sectional study, with follow-up between 6 months to 1 year after commencement of treatment. A survey form was posted to 1150 subjects, identified in the regional register over a 1-year period as having been treated with an OA for OSA. The questionnaire comprised 70 questions and assertions in various domains, such as general health/lifestyle, changes in symptoms/quality of life and sleep-related experiences, daytime sleepiness, changes in life situation, evaluation of treatment and the value of treatment. The overall response rate was 64% (n = 738). Treatment with OA gave relief of symptoms in 83% of the respondents. Quality of life, somatic and cognitive symptoms improved significantly in patients who used the appliance frequently (P < 0·001). Daytime sleepiness decreased significantly (P < 0·001). Treatment satisfaction and willingness to recommend the similar treatment to a friend were high (>85%). OA treatment of OSA by general dental practitioners is a safe procedure. Most of the survey respondents experienced relief of symptoms. Those who used their appliance frequently reported improvement in quality of life, somatic and cognitive symptoms. Excessive daytime sleepiness was reduced in the majority of the patients under treatment.

The use of positive airway pressure therapy for treatment of resistant hypertension

It is well accepted that obstructive sleep apnea (OSA) is a risk factor for hypertension. In the subgroup of patients with resistant hypertension (rHTN), OSA appears to be particularly rampant; suggesting sleep disordered breathing may contribute to pathological mechanisms that make blood pressure difficult to control. This article explores potential mechanisms by which sleep apnea contributes to rHTN, and examines the impact of treating OSA with positive airway pressure therapy on blood pressure control. In recent years, there has been a surge of interest in randomized controlled trials of positive airway pressure therapy in patients with OSA and rHTN, because patients with rHTN respond poorly to medications. As a result, identifying novel targets for blood pressure control in this high-risk population has become paramount.

Hypertension and obstructive sleep apnea

Obstructive sleep apnea (OSA) is a major modifiable risk factor of hypertension and hypertensive patients with OSA are at increased risk for cardiovascular diseases. A substantial number of studies have revealed that OSA and hypertension have synergistic effects on the cardiovascular system and, therefore, it is clinically important and relevant to increase our understanding of the pathophysiological interactions between OSA and hypertension. In our present review, after briefly reviewing the characteristics and pathophysiological effects of OSA, we focus on the current understanding of OSA-associated hypertension, the potential approaches for treatment of OSA and the effect of OSA treatment on hypertension management. We hope our present review will shed light for future studies that investigate effective therapeutic strategies to simultaneously improve the management of OSA and hypertension.

Continuous Positive Airway Pressure in Patients With Obstructive Sleep Apnea and Resistant Hypertension: A Meta-Analysis of Randomized Controlled Trials

This study aimed to analyze the effect of continuous positive airway pressure (CPAP) on blood pressure (BP) in patients with obstructive sleep apnea (OSA) and resistant hypertension. Randomized controlled trials (RCTs) that evaluated the effect of CPAP on BP in patients with OSA and resistant hypertension, indexed in MEDLINE, Embase, and the Cochrane Library from inception until March 20, 2015, were included in the meta-analysis. A total of five RCTs were identified to meet the inclusion criteria. The pooled changes after CPAP treatment for 24-hour ambulatory systolic BP and diastolic BP (DBP) were -4.78 mm Hg (95% confidence interval [CI], -7.95 to -1.61) and -2.95 mm Hg (95% CI, -5.37 to -0.53) in favor of the CPAP group. CPAP was also associated with reduction in nocturnal DBP (mean difference, -1.53 mm Hg, 95% CI, -3.07 to 0). The results indicated a favorable reduction in BP with CPAP treatment in patients with OSA and resistant hypertension.

Does continuous positive airway pressure reduce aldosterone levels in patients with obstructive sleep apnea?

PURPOSE

Aldosterone is associated with the development of obstructive sleep apnea (OSA) and cardiovascular diseases. Continuous positive airway pressure (CPAP) is an effective treatment for OSA, but the impact of CPAP therapy on aldosterone levels in patients with OSA remains unclear. To address this issue, a meta-analysis was conducted to evaluate the effects of CPAP therapy on serum aldosterone levels in OSA.

METHODS

Two reviewers independently searched PubMed, Cochrane library, Embase, and Web of Science before March 2015. Information on characteristics of subjects, study design, and pre- and post-CPAP treatment of serum aldosterone was extracted for analysis. Standardized mean difference (SMD) was calculated to estimate the treatment effects of CPAP therapy.

RESULTS

A total of 5 studies involving 329 patients were pooled into this meta-analysis, including 3 observational studies and 2 randomized controlled studies. Results indicated significantly decreased aldosterone levels after CPAP therapy (SMD = -0.236, 95 % confidence interval (CI) = -0.45 to -0.02, z = 2.12, p = 0.034).

CONCLUSIONS

This meta-analysis suggested that CPAP therapy was associated with a decrease in serum aldosterone in patients with OSA. Further large-scale, well-designed interventional investigations are needed to clarify this issue.

Evaluation of obstructive sleep apnea symptoms in pregnant women with chronic disease

OBJECTIVE

Obstructive sleep apnea syndrome (OSAS) is a disease which is estimated to be undiagnosed to a large extent. Hence, the prevalence of OSAS in pregnant women is unknown. We aimed to evaluate the symptoms of obstructive sleep apnea in pregnant women with chronic diseases.

METHODS

In the study, 97 pregnant women with chronic diseases and 160 healthy pregnant women were included. A form questioning socio-demographic characteristics and pregnancy characteristics, Epworth scale and the Berlin questionnaire to evaluate the risk of OSAS were applied to participants.

RESULTS

It has been determined that 10-12.5% of healthy pregnant women, 34-45.4% of pregnants with chronic diseases and 20.6-23.3% of all pregnant women had a high risk of OSAS, the pregnants with chronic disease compared to healthy pregnant women had statistically significant higher risk of OSAS. The risk of OSAS was found to be significantly higher especially in pregnant women with hypertension and diabetes.

CONCLUSIONS

OSAS can lead to the adverse consequences in pregnancy, should be questioned for all pregnants especially those with chronic diseases. Pregnant women with OSAS should be monitored more carefully in terms of diabetes and hypertension in antenatal care.

Peritoneal Dialysis is Associated With A Better Survival in Cirrhotic Patients With Chronic Kidney Disease

Peritoneal dialysis (PD) can be an ideal treatment in cirrhotic patients with ascites and chronic kidney disease stage 5 (CKD 5D) who require dialysis. The survival of cirrhotic patients with CKD 5D on PD, however, is not clear. We compared the survival of cirrhotic patients with CKD 5D on PD and the survival of those on HD. Two datasets including a cohort study of China Medical University Hospital (CMUH) from 2004 to 2013 and the Longitudinal National Health Insurance Database for Catastrophic Illness Patients (LHID-CIP) of Taiwan from 1996 to 2011 were analyzed. The survival of cirrhotic patients on PD and the propensity score matched cirrhotic patients on HD were analyzed using Cox proportional hazards regression. In CMUH cohort of 85 PD and 340 HD patients, the all-cause mortality was lower in PD patients compared to it in HD patients (hazard ratio [HR]: 0.48, 95% confidence interval [CI]: 0.31-0.74, P < 0.01) after adjustments for confounders. The severity of liver cirrhosis defined by Child-Turcotte-Pugh (CTP) class (P < 0.01) was independently associated with all-cause mortality. The model for end-stage liver disease (MELD) score, however, was not associated with all-cause mortality. In the LHID-CIP cohort of 285 PD and 1140 HD patients, the HR of all-cause mortality in PD patients was 0.61 (95% CI: 0.47 - 0.79, P < 0.01), as compared with HD patients. PD in cirrhotic patients who need dialysis is associated with lower all-cause mortality than HD is. This association is independent of patients' comorbidity, severity of liver cirrhosis, and serum albumin levels.