Sleep apnea: State of the art

Feasibility and acceptability of switching from a previous-generation to a new-generation mask for positive airway pressure therapy of sleep apnea using remote care

Purpose

Mask selection could affect an individual's experience with positive airway pressure (PAP) treatment for obstructive sleep apnea, but there is very limited data on the impact of switching to a different mask once established on PAP therapy. This study investigated the patient's experience when switching from a previous-generation PAP mask to a new-generation mask via remote care.

Methods

A new-generation mask (AirFit F30i or AirFit N30i) was successfully fitted to 215 participants during video conferencing sessions. Participants completed online questionnaires on day 1, day 3, day 7, day 30 and day 90 after mask switch to collect subjective feedback and quality of life data; objective PAP device data were also downloaded.

Results

Residual apnea-hypopnea index showed statistically significant difference from baseline at day 30 (+0.2 ± 0.9/h [p = 0.026]) and day 90 (+0.2 ± 0.8/h [p = 0.006]), however unlikely to be clinically relevant. Average daily usage was significantly increased from baseline at day 30 (+0.2 ± 1.2 h/day [p = 0.010]) but not day 90 (+0.1 ± 1.0 h/day [p = 0.126]). Functional Outcomes of Sleep Questionnaire (FOSQ-10) score was significantly higher at day 90 (change from baseline to day 90: +0.48 ± 2.29 [p = 0.015]). Subjective ratings for comfort, seal, and usability of the new-generation mask were significantly better than the predefined acceptability level. Rates of PAP-related side effects were generally acceptable.

Conclusion

Remote management of mask change was associated with good outcomes in terms of objective device data and patient acceptability. This approach could be used to improve the overall therapy experience for individuals requiring a PAP therapy mask change for any reason.

Clinical trial registration

http://clinicaltrials.gov (NCT05262439).

Morphometric measures and desaturations: Proposal for an index with improved accuracy for obstructive sleep apnea screening

STUDY OBJECTIVE

To evaluate the sensitivity and specificity of the combined Kushida morphometric model (KMM) and the oxygen desaturation index (ODI) for screening individuals with obstructive sleep apnea.

METHODS

Diagnostic test study with adults >18 years, both sexes, polysomnography, body mass index, neck circumference and intraoral measurements.

RESULTS

144 patients were invited; of these, 75 met the exclusion criteria. 55 individuals presented AHI ≥5 ev/h and 14, an AHI <5 ev/h. Three AHI cut-off points were evaluated: AHI ≥5, ≥15, ≥30 ev/h. When adopting the cut-off point of AHI ≥5 ev/h, the KMM showed sensitivity (SE) = 60.0 %, specificity (SP) = 71.4 % and 95 % confidence interval of the area under the curve (95 % CI of AUC) = 0.655; the combination of KMM and ODI (KMM + ODI) revealed SE = 73.0 %, SP = 71.4 % (95 % CI of AUC = 0.779) and the ODI showed SE = 76.4 % and SP = 92.9 % (95 % CI of AUC = 0.815). At the cut-off point of AHI ≥15 ev/h, the KMM presented SE = 64.1 %, SP = 76.7 % (95 % CI of AUC = 0.735); the KMM + ODI showed SE = 82.1 %, SP = 83.3 % (95 % CI of AUC = 0.895); and the ODI presented SE = 76.9 %, SP = 100.0 % (95 % CI of AUC = 0.903). For the cut-off point of AHI ≥30 ev/h, the KMM showed SE = 56.0 %, SP = 77.2 % (95 % CI of AUC = 0.722); the KMM + ODI revealed SE = 92.0 %, SP = 79.5 % (95 % CI of AUC = 0.926); and the ODI showed SE = 92.0 %, SP = 90.9 % (95 % CI of AUC = 0.941).

CONCLUSION

The combination of oxygen desaturation index and Kushida morphometric model improved the sensitivity and specificity of this model regardless of obstructive sleep apnea severity suggesting greater effectiveness in risk prediction.

Estimated prevalence of obstructive sleep apnea by occupation and industry in England: a descriptive study

Study Objectives

Obstructive sleep apnea (OSA) can induce excessive sleepiness, causing work-related injuries and low productivity. Most individuals with OSA in the United Kingdom are undiagnosed, and thus, theoretically, workplace screening, might by identifying these individuals improve both their individual health and overall productivity. However, the prevalence of OSA in different workplaces is unclear. This study aimed to estimate the prevalence of OSA by industries and occupations in England.

Methods

The Health Survey for England 2019 dataset was combined with Sleep Heart Health Study dataset. We applied multiple imputation for the combined dataset to estimate OSA in the English population aged 40-64. We estimated the pooled prevalence of OSA by both industry and occupation by separating samples by Standard Industry Classification and Standard Occupation Classification.

Results

The overall OSA prevalence estimated by imputation for ages 40-64 was 17.8% (95% CI = 15.9% to 19.9%). Separating those samples into industrial/occupational groups, the estimated prevalence of OSA varied widely by industry/occupation. Descriptive analysis revealed that the estimated prevalence of OSA was relatively higher in the Accommodation and food, Public administration and defence; compulsory social security, Construction industries, and Protective service occupations, health and social care associate professionals, and skilled construction and building trades occupations.

Conclusions

In England in 2019, Accommodation and food, Public administration and defence; compulsory social security, Construction industries, and Protective service occupations, health and social care associate professionals, and skilled construction and building trades occupations showed a relatively higher prevalence of OSA indicating that they may be target populations for workplace screening.

The association of diabetes with progression of sleep-disordered breathing based on a prospective cohort

AIM

Prospective studies suggest that sleep-disordered breathing enhances the risk of diabetes. However, it remains unclear whether diabetes could worsen sleep-disordered breathing.

METHODS

The participants from Sleep Heart Health Study underwent two polysomnograms at a 5-year interval. The relationship of baseline diabetes to change in the apnoea-hypopnoea index (AHI) was examined based on general linear models, adjusting for demographics, lifestyles, history of hypertension, pulmonary function, length of follow-up and baseline AHI.

RESULTS

In total, 161 of the 2603 participants were diagnosed with diabetes at the first polysomnograms. Compared with participants without diabetes, those with diabetes had a higher baseline and larger increases in follow-up AHI and obstructive apnoea index (oAI). Diabetes increased 2.52 events per hour (95% confidence interval 0.45-4.59; p = .017) for AHI change and 1.13 events per hour (95% confidence interval 0.04-2.23; p = .042) for oAI change, respectively. In addition, subgroup analysis suggested that the association was consistent across baseline obstructive sleep apnoea severity and body mass index groups.

CONCLUSIONS

Baseline diabetes was associated with worsening sleep-disordered breathing over 5 years, which mainly increased the change in AHI and oAI.

Dental Sleep Medicine Education Amongst Accredited Orthodontic Programmes in Thailand

BACKGROUND

Dental sleep medicine education (DSME) should be emphasised in postgraduate orthodontic training; however, there appears to be no clear guideline for its implementation into the curriculum.

OBJECTIVE

The aim was to investigate the current status of DSME as well as its feasibility and implementation in postgraduate orthodontic programmes.

METHODS

A structured interview with predetermined response options was chosen as a data collection method to gather relevant information from representatives of all accredited postgraduate orthodontic programmes in Thailand. These interviews were conducted online via the Cisco Webex Meeting platform. A combination of data analysis techniques was employed to achieve a thorough comprehension of the research findings, including descriptive statistics, quantitative content analysis, thematic analysis, and alignment analysis.

RESULTS

All participating programmes reported the inclusion of DSME in their curricula. A didactic approach was adopted by all programmes. However, only 2 out of 7 programmes offered clinical sessions for their students. Several challenges in implementing DSME within orthodontic programmes were identified, including a shortage of expertise and limited patient access. The participants also suggested that knowledge and resource sharing amongst institutions could serve as a potential solution to enhance the feasibility of DSME.

CONCLUSIONS

This research highlighted the significant disparities and inadequacy of DSME within postgraduate orthodontic programmes in Thailand due to various challenges. Consequently, there is a compelling need to place greater emphasis on DSME and establish a national-level standardisation within orthodontic programmes. This effort is essential for enhancing the awareness and competency of orthodontists in the field of DSME.

[Changes the level of differentiating growth factor - GDF 15 in patients with sleep apnea syndrome after aPAP-therapy: pilot study]

OBJECTIVE

Comparative assessment of the level of differentiating growth factor 15 (GDF 15 ) against the background of a 6-month course of respiratory support in the mode of automatic positive pressure in the airways therapy (aPAP therapy) in patients with obstructive sleep apnea syndrome (OSA).

MATERIAL AND METHODS

59 men participated in the study, the average age was 51.9±2.4 years. The main group (MG1) consisted of 30 patients with a verified diagnosis of moderate OSA. 29 men of comparable age and body weight made up the control group (CG) without an objectively confirmed diagnosis of OSA. After the stage of introduction into the study, the type of respiratory support with individual pressure settings was selected for patients with MG1. After 6 months of aPAP therapy with high compliance (at least 85%), the same patients who made up MG2 after treatment underwent repeated polysomnography (PSG) and the GDF 15 content was evaluated. Methods: questionnaire, examination, polysomnography, enzyme immunoassay of blood serum to determine the content of GDF 15.

RESULTS

A 6-month course of aPAP therapy with a high degree of compliance significantly improved the sleep structure and breathing pattern: the representation of NREM 3 increased from 79.2±15.6 to 102.6±21.6 minutes and the REM phase from 56.9± 13.6 to 115.6±26.8. Episodes of apnea were eliminated - apnea-hypopnea index decreased from 21.1 [17.3; 39.1] to 2.5 [1.8; 4.6] and the average values of SaO2 increased from 85.9% to 91.5%. At the same time, a statistically significant excess of GDF 15 was revealed in MG1 - 20.4 [14.16; 31.71] and MG2 - 17.2 [13.63; 24.44]) in comparison with CG - 13.65 [10.7; 17.09]. Despite the lack of statistical significance, a change in the level of GDF 15 was revealed in the form of a decrease in its concentration after a 6-month course of aPAP therapy.

CONCLUSION

A 6-month course of aPAP therapy made it possible to eliminate intermittent nocturnal hypoxia and improve sleep structure in patients with OSA, as well as reduce the content of GDF 15 protein in blood serum in patients with OSA. However, the tendency to decrease the content of this protein, despite the lack of statistical reliability, confirms the effectiveness of OSA therapy and the possibility of preventing early and pathological aging from the standpoint of somnology and molecular biogerontology.

REM-OSA as a Tool to Understand Both the Architecture of Sleep and Pathogenesis of Sleep Apnea-Literature Review

Sleep is a complex physiological state, which can be divided into the non-rapid eye movement (NREM) phase and the REM phase. Both have some unique features and functions. This difference is best visible in electroencephalography recordings, respiratory system activity, arousals, autonomic nervous system activity, or metabolism. Obstructive sleep apnea (OSA) is a common condition characterized by recurrent episodes of pauses in breathing during sleep caused by blockage of the upper airways. This common condition has multifactorial ethiopathogenesis (e.g., anatomical predisposition, sex, obesity, and age). Within this heterogenous syndrome, some distinctive phenotypes sharing similar clinical features can be recognized, one of them being REM sleep predominant OSA (REM-OSA). The aim of this review was to describe the pathomechanism of REM-OSA phenotype, its specific clinical presentation, and its consequences. Available data suggest that in this group of patients, the severity of specific cardiovascular and metabolic complications is increased. Due to the impact of apneas and hypopneas predominance during REM sleep, patients are more prone to develop hypertension or glucose metabolism impairment. Additionally, due to the specific function of REM sleep, which is predominantly fragmented in the REM-OSA, this group presents with decreased neurocognitive performance, reflected in memory deterioration, and mood changes including depression. REM-OSA clinical diagnosis and treatment can alleviate these outcomes, surpassing the traditional treatment and focusing on a more personalized approach, such as using longer therapy of continuous positive airway pressure or oral appliance use.

Electrocardiogram Monitoring Wearable Devices and Artificial-Intelligence-Enabled Diagnostic Capabilities: A Review

Worldwide, population aging and unhealthy lifestyles have increased the incidence of high-risk health conditions such as cardiovascular diseases, sleep apnea, and other conditions. Recently, to facilitate early identification and diagnosis, efforts have been made in the research and development of new wearable devices to make them smaller, more comfortable, more accurate, and increasingly compatible with artificial intelligence technologies. These efforts can pave the way to the longer and continuous health monitoring of different biosignals, including the real-time detection of diseases, thus providing more timely and accurate predictions of health events that can drastically improve the healthcare management of patients. Most recent reviews focus on a specific category of disease, the use of artificial intelligence in 12-lead electrocardiograms, or on wearable technology. However, we present recent advances in the use of electrocardiogram signals acquired with wearable devices or from publicly available databases and the analysis of such signals with artificial intelligence methods to detect and predict diseases. As expected, most of the available research focuses on heart diseases, sleep apnea, and other emerging areas, such as mental stress. From a methodological point of view, although traditional statistical methods and machine learning are still widely used, we observe an increasing use of more advanced deep learning methods, specifically architectures that can handle the complexity of biosignal data. These deep learning methods typically include convolutional and recurrent neural networks. Moreover, when proposing new artificial intelligence methods, we observe that the prevalent choice is to use publicly available databases rather than collecting new data.

Clinical significance of obstructive sleep apnea in patients with acute coronary syndrome with or without prior stroke: a prospective cohort study

BACKGROUND AND OBJECTIVE

Whether obstructive sleep apnea (OSA) is associated with worse prognosis in patients with acute coronary syndrome (ACS) with or without prior stroke remains unclear. We investigated the association of OSA with cardiovascular events in ACS patients with or without prior stroke.

METHODS

Between June 2015 and January 2020, we prospectively recruited eligible ACS patients who underwent cardiorespiratory polygraphy during hospitalization. We defined OSA as an apnea hypopnea index (AHI) ≥ 15 events/hour. The primary composite end point was major adverse cardiovascular and cerebrovascular events (MACCEs), including cardiovascular death, myocardial infarction, stroke, ischemia-driven revascularization, or hospitalization for unstable angina or heart failure.

RESULTS

Among 1927 patients enrolled, 207 patients had prior stroke (10.7%) and 1014 had OSA (52.6%). After a mean follow-up of 2.9 years, patients with stroke had significantly higher risk of MACCEs than those without stroke (hazard ratio [HR]:1.49; 95% confidence interval [CI]: 1.12-1.98, P = 0.007). The multivariate analysis showed that patients with OSA had 2.0 times the risk of MACCEs in prior stroke group (41 events [33.9%] vs 18 events [20.9%]; HR:2.04, 95% CI:1.13-3.69, P = 0.018), but not in non-prior stroke group (186 events [20.8%] vs 144 events [17.4]; HR:1.21, 95% CI 0.96-1.52, P = 0.10). No significant interaction was noted between prior stroke and OSA for MACCE (interaction P = 0.17).

CONCLUSIONS

Among ACS patients, the presence of OSA was associated with an increased risk of cardiovascular events in patients with prior stroke. Further trials exploring the efficacy of OSA treatment in high-risk patients with ACS and prior stroke are warranted. Trial registration Clinicaltrials.gov identifier NCT03362385.

Salivary parameters and periodontal inflammation in obstructive sleep apnoea patients

The aim of this cross-sectional study was to objectively assess the salivary flow rate and composition and periodontal inflammation in obstructive sleep apnoea (OSA) patients. The subjects, who underwent whole-night polysomnography or polygraphy, were referred for saliva sampling and periodontal examination. According to the severity of OSA based on the Apnoea Hypopnea Index (AHI) value, the subjects were classified into groups: no OSA (AHI < 5; N = 17), mild to moderate OSA (AHI 5-29.9; N = 109), and severe OSA (AHI > 30; N = 79). Salivary flow rate, pH, salivary electrolytes, and cortisol were measured from collected saliva samples. Periodontal examination included assessment of the number of teeth, dental plaque, bleeding on probing and periodontal measurements: gingival recession, probing pocket depth, clinical attachment level (CAL) and periodontal inflamed surface area (PISA) score. There were no significant differences in salivary flow rate, salivary pH, salivary electrolyte concentrations or electrolyte ratios among the groups classified according to the severity of OSA. However, subjects without OSA had higher salivary cortisol concentrations than OSA groups (p < 0.001). Increased plaque scores were associated with a higher AHI (r = 0.26; p = 0.003). According to the salivary flow rate, subjects with hyposalivation and reduced salivation had higher concentrations of salivary electrolytes and lower salivary pH than subjects with normal salivation. Subjects with hyposalivation had an increased Mg/PO₄ ratio (p < 0.001) and a reduced Ca/Mg ratio (p < 0.001). Furthermore, subjects with severe OSA tended to have higher CALs and plaque volumes. In conclusion, under pathological conditions, such as OSA, multiple interactions might impact salivary flow and electrolyte composition. Complex interrelationships might affect the integrity of oral health, especially considering OSA severity, inflammation, concomitant diseases and medications.

Prevalence of sleep-disordered breathing in an African general population: The Benin Society and Sleep (BeSAS) study

BACKGROUND

Data on the prevalence of sleep-disordered breathing (SDB) in the African general population are scarce, and a better understanding is urgently needed. Our study aimed to objectively determine the prevalence of, and factors associated with, SDB in a large sample in Benin, west Africa.

METHODS

In the Benin Society and Sleep (BeSAS) cross-sectional study, participants aged 25 years and older were recruited from both urban and rural areas. Rural participants were recruited from Tanve, a village located 200 km north of Cotonou, and urban participants were recruited from Cotonou. The participants underwent respiratory polygraphy at home using a type-3 device that measures airflow through a nasal pressure sensor, respiratory effort (thoracic movement), and pulse oximetry. Clinical and morphometric data were also collected. SDB severity categories were defined according to the apnoea-hypopnoea index (AHI), with mild-to-severe SDB (AHI ≥5/h), moderate-to-severe SDB (AHI ≥15/h), and severe SDB (AHI ≥30/h).

FINDINGS

The study was completed from April 4, 2018 to Jan 15, 2021. Of 2909 participants recruited in the BeSAS study, 2168 (74·5%) underwent respiratory polygraphy. For the 1810 participants with complete polygraphic data (mean age 46 years, SD 15; 1163 [64·2%] women), the prevalence of mild-to-severe SDB (AHI ≥5/h) was 43·2% (95% CI 40·9-45·5), of moderate-to-severe SDB (AHI ≥15/h) was 11·6% (10·2-13·1), and of severe SDB (AHI ≥30/h) was 2·7% (2·0-3·5). Factors independently associated with SDB were advanced age, male sex, large neck circumference, abdominal obesity, overweight or obesity, and snoring. After multivariable adjustment, severe SDB was independently associated with hypertension in women (odds ratio 3·99, 95% CI 1·04-15·33; p_trend=0·044), but not in men (odds ratio 0·67, 0·22-2·05; P_trend=0·63).

INTERPRETATION

The BeSAS study provides the first large-scale objective evaluation of SDB prevalence and associated factors in Africa. The high prevalence of SDB identified should stimulate the development of public health policies to prevent and treat this condition in African countries.

FUNDING

Ligue Pulmonaire Vaudoise, Switzerland.

Association between sleep-disordered breathing and periodontal diseases: A systematic review protocol

Background

Sleep-disordered breathing (SDB) is a chronic sleep-related breathing disorder, considered associated with increased risk of cardiovascular disorders, metabolic disorders, cognitive dysfunction and behavior changes. Periodontal diseases are chronic infectious diseases that are also believed to be associated with cardiovascular diseases, metabolic syndrome and cognitive dysfunction. Several studies have indicated that SDB may be associated with periodontal diseases through certain mechanisms such as inflammation response, oxidative stress and oral dryness. The aim of this systematic review is to explore the association between SDB and periodontal diseases in an integrated approach.

Materials and Methods

This systematic review will include cohort studies, cross-sectional studies and case-control studies that are identified by electronic and manual searches. Electronic searches will be conducted in the following databases: PubMed, Embase, Scopus and Web of Science. Our search will cover articles published from inception of databases to March 2022 without restrictions in language and settings. Pre-determined eligibility criteria include: participants (participants without a history of respiratory diseases, history of periodontal treatment within the past 6 months and history of medication that is known to influence SDB or periodontal diseases); exposure (participants who have been diagnosed with SDB or at high-risk for SDB); comparison (participants without SDB); and outcome (periodontal parameters, such as probing depth, clinical attachment level, bleeding on probing, radiographic bone loss). Two authors will perform study screening and data extraction independently and in duplicate. All discrepancies will be solved by discussion. The methodological quality of included studies will be assessed using the Newcastle-Ottawa Scale.

Discussion

This systematic review will summarize the existing evidence on the association between SDB and periodontal diseases, a topic of controversy and clinical significance. Its findings can provide evidence for the development of relevant prevention and treatment strategies. The results will be disseminated through peer-reviewed journals.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42022313024. Registered on March 28th 2022.

Female sex hormones and symptoms of obstructive sleep apnea in European women of a population-based cohort

Background

The prevalence of obstructive sleep apnea is higher in women after menopause. This is suggested to be a result of an altered sex hormone balance but has so far not been confirmed in a population-based study.

Objective

To investigate whether serum concentration of estrogens and progesterone are associated with the prevalence of sleep apnea symptoms in middle-aged women of the general population.

Methods

We analyzed data from 774 women (40–67 years) from 15 study centers in seven countries participating in the second follow-up of the European Community Respiratory Health Survey (2010–2012). Multiple logistic regression models were fitted with self-reported symptoms of sleep apnea as outcomes and serum concentrations of various estrogens and progesterone as predictors. All analyses were adjusted for relevant covariates including age, BMI, education, study center, smoking habits, and reproductive age.

Results

Among all included women, a doubling of serum concentrations of estrone and progesterone was associated with 19% respectively 9% decreased odds of snoring. Among snorers, a doubling of the concentrations of 17β-estradiol, estrone and estrone 3-sulfate was associated with 18%, 23% and 17% decreased odds of breathing irregularly, and a doubling of the progesterone concentration was further associated with 12% decreased odds of waking up suddenly with a chocking sensation. Other evaluated associations were not statistically significant.

Conclusions

Middle-aged women with low serum estrogen and progesterone levels are more likely to snore and report symptoms of obstructive sleep apnea.

The role of monoaminergic neurons in modulating respiration during sleep and the connection with SUDEP

Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death among epilepsy patients, occurring even more frequently in cases with anti-epileptic drug resistance. Despite some advancements in characterizing SUDEP, the underlying mechanism remains incompletely understood. This review summarizes the latest advances in our understanding of the pathogenic mechanisms of SUDEP, in order to identify possible targets for the development of new strategies to prevent SUDEP. Based on our previous research along with the current literature, we focus on the role of sleep-disordered breathing (SDB) and its related neural mechanisms to consider the possible roles of monoaminergic neurons in the modulation of respiration during sleep and the occurrence of SUDEP. Overall, this review suggests that targeting the monoaminergic neurons is a promising approach to preventing SUDEP. The proposed roles of SDB and related monoaminergic neural mechanisms in SUDEP provide new insights for explaining the pathogenesis of SUDEP.

A Model for Sleep Apnea Management in Underserved Patient Populations

INTRODUCTION

Obstructive sleep apnea (OSA) is a common condition in the United States that is strongly linked to metabolic disease, cardiovascular disease, and increased mortality. Uninsured populations experience sleep health disparities, including delayed recognition, diagnosis, and treatment of OSA due to barriers accessing and affording care. Partnerships between primary care clinics and sleep medicine specialists for sleep apnea management have the potential to increase screening, testing, and treatment among underserved populations. Here, we present an integrated and cost-effective model that is easier to navigate for patients while maintaining high quality care.

METHODS

We designed and implemented a specialty sleep clinic at Shade Tree Clinic, Vanderbilt's student-run, free primary care clinic. Patients with signs and symptoms of OSA were identified at primary care appointments and screened using the STOP-BANG questionnaire. Clinic visits took place over telehealth with a medical student and sleep specialist. Patients were diagnosed using a home sleep test, and if indicated, were prescribed and given a CPAP device for treatment. CPAP adherence was monitored using a cloud-based remote monitoring system.

RESULTS

From December 2020 through August 2021, we hosted 6 telehealth Sleep Clinics, seeing a total of 28 patients across these visits. We have received a total of 37 referrals and have coordinated sleep evaluations and diagnostic testing for 18 of these patients so far. Prior to initiation of the sleep clinic, there were 17 patients on our primary care panel at Shade Tree with a diagnosis of OSA. These patients were using donated equipment and many had been lost to follow-up or had broken parts. We were able to replace 10 of these patient's CPAP devices and plan to replace the remaining seven.

CONCLUSIONS

We have created a model of integrated specialty care that is efficient and cost-effective. This paradigm can be replicated for the many specialties that are typically overlooked and undertreated when working with uninsured patients. As awareness of this sleep medicine program becomes more widespread at Shade Tree Clinic, we anticipate reaching more primary care patients with signs and symptoms of sleep apnea through student education, cost-effective diagnostics, and partnership with sleep specialists.

Six Months of Inspiratory Muscle Training to Lower Blood Pressure and Improve Endothelial Function in Middle-Aged and Older Adults With Above-Normal Blood Pressure and Obstructive Sleep Apnea: Protocol for the CHART Clinical Trial

Background: Cardiovascular disease is a major global health concern and prevalence is high in adults with obstructive sleep apnea (OSA). Lowering blood pressure (BP) can greatly reduce cardiovascular disease risk and physical activity is routinely prescribed to achieve this goal. Unfortunately, many adults with OSA suffer from fatigue, daytime sleepiness, and exercise intolerance—due to poor sleep quality and nocturnal hypoxemia—and have difficulty initiating and maintaining an exercise program. High-resistance inspiratory muscle strength training (IMST) is a simple, time-efficient breathing exercise consistently reported to reduce BP in small, selective groups of both healthy and at-risk adults. Herein we present the study protocol for a randomized clinical trial to determine the long-term efficacy of IMST performed regularly for 24 weeks in middle-aged and older adults with OSA. The primary outcome is casual systolic BP. Secondary outcomes are 24-h systolic BP and circulating plasma norepinephrine concentration. Other outcomes include vascular endothelial function (endothelial-dependent and -independent dilation), aortic stiffness, casual and 24-h diastolic BP, and the influence of circulating factors on endothelial cell nitric oxide and reactive oxygen species production. Overall, this trial will establish efficacy of high-resistance IMST for lowering BP and improving cardiovascular health in middle-aged and older adults with OSA.

Methods: This is a single-site, double-blind, randomized clinical trial. A minimum of 92 and maximum of 122 male and female adults aged 50–80 years with OSA and above-normal BP will be enrolled. After completion of baseline assessments, subjects will be randomized in a 1:1 ratio to participate in either high-resistance or sham (low-resistance) control IMST, performed at home, 5 min/day, 5 days/week, for 24 weeks. Repeat assessments will be taken after the 24-week intervention, and after 4 and 12 weeks of free living.

Discussion: This study is designed to assess the effects of 24 weeks of IMST on BP and vascular function. The results will characterize the extent to which IMST can reduce BP when performed over longer periods (i.e., 6 months) than have been assessed previously. Additionally, this study will help to determine underlying mechanisms driving IMST-induced BP reductions that have been reported previously.

Clinical Trial Registration: This trial is registered with ClinicalTrials.gov (Registration Number: NCT04932447; Date of registration June 21, 2021).

An organ systems-based review of outcomes associated with sleep apnea in hospitalized patients

The current global health crisis due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has prompted the medical community to investigate the effects of underlying medical conditions, including sleep-disordered breathing, on inpatient care. Obstructive sleep apnea (OSA) is a common form of sleep-disordered breathing that may complicate numerous acquired conditions, particularly in inpatient and critical care settings. Viral pneumonia is a major contributor to intensive care unit (ICU) admissions and often presents more severely in patients with underlying pulmonary disease, especially those with obesity and OSA. This review summarizes the most recent data regarding complications of both OSA and obesity and highlights their impact on clinical outcomes in hospitalized patients. Additionally, it will highlight pertinent evidence for the complications of OSA in an organ-systems approach. Finally, this review will also discuss impatient treatment approaches for OSA, particularly in relation to the SARS-CoV-2 pandemic.

Incidence of peripheral vestibular disorders in individuals with obstructive sleep apnea

BACKGROUND

Obstructive sleep apnea(OSA) could influence peripheral vestibular function adversely via intermittent hypoxia and its consequences.

OBJECTIVE

This study aimed to evaluate the risk of peripheral vestibular disorders in OSA using a nationwide population-based retrospective cohort study.

METHODS

The National Health Insurance Service-National Sample Cohort represents the entire Korean population from 2002 to 2015. OSA was defined as individuals who had used medical services twice or more under a diagnosis of OSA(G47.33 in ICD-10). A comparison cohort consisted of socio-demographically matched non-OSA subjects in a ratio of 1:4. The incidences of benign paroxysmal positional vertigo(BPPV), Meniere's disease, and vestibular neuritis were evaluated in each cohort.

RESULTS

A total of 2,082 individuals with OSA and 8,328 matched non-OSA subjects were identified. The incidence rates(IRs) of peripheral vertigo in OSA and non-OSA were 149.86 and 23.88 per 10,000 persons, respectively (Ratio of IR, IRR = 6.28, 95%CI 4.89 to 8.08). In multivariable analysis, the risk of peripheral vertigo was significantly higher in OSA(adjusted HR = 6.64, 95%CI 5.20 to 8.47), old age(adjusted HR = 1.03, 95%CI 1.02 to 1.04), female sex(adjusted HR = 1.92, 95%CI 1.48 to 2.50), and comorbidities(adjusted HR = 1.09, 95%CI 1.003 to 1.19). The IRRs of each vestibular disorder in the two groups were 7.32(95%CI 4.80 to 11.33) for BPPV, 3.61(95%CI 2.24 to 5.81) for Meniere's disease, and 9.51(95%CI 3.97 to 25.11) for vestibular neuritis.

CONCLUSIONS

Subjects diagnosed with OSA had a higher incidence of peripheral vestibular disorders than those without OSA, according to national administrative claims data. It is recommended to take peripheral vertigo into account when counseling OSA.

Knowledge and Attitude of Dentists Towards Obstructive Sleep Apnoea

BACKGROUND

Obstructive sleep apnoea (OSA) is the most common sleep-related breathing disorder. Dentists should play an essential role in OSA screening, referral, and management. However, few studies have investigated dentists' knowledge and attitude towards OSA.

OBJECTIVE

This cross-sectional survey aimed to assess the level of knowledge and attitude regarding OSA amongst dentists and evaluate whether the level of knowledge affects their attitude towards OSA.

METHODS

Using the Google Forms platform, an online questionnaire was distributed via e-mail to all Ministry of Health dentists (N = 352). The questionnaire included 3 sections: demographics, knowledge, and attitude. Participant responses were stratified by professional title (general dentists, specialists, or consultants) and practice sector (primary health care centres or hospitals). Descriptive statistics, independent t tests, one-way analyses of variance, and Pearson's correlation were used to analyse the data.

RESULTS

Of the 352 dentists, 191 responded to the questionnaire (54.55%). Although 80.6% of the respondents reported having previous OSA knowledge in the self-assessment question, 65.58% scored below 12 in the total knowledge scores, and 63.35% scored below 3 in the total attitude scores based on Bloom's cutoff. The mean total knowledge score was 9.86, while the mean total attitude score was 2.08. No significant differences between the mean total knowledge and attitude scores were found based on sex, professional title, or practice sector. A positive and statistically significant correlation was found between total knowledge and attitude scores (P value = .001).

CONCLUSIONS

This study showed that dentists had a low OSA-related knowledge and a negative attitude towards OSA, and a positive association was seen between knowledge level and attitude. Dental practitioners with high knowledge scores tended to have a positive attitude towards OSA. These findings suggest that dentists in Jeddah require more education and clinical training in sleep medicine to maximise patient benefits and minimise adverse outcomes.

An alternative model in the provision of CPAP in sleep apnea: a comparative cost analysis

BACKGROUND

To conduct a pilot study on an alternative model for the provision of respiratory therapies in sleep apnea-hypopnea syndrome (SAHS) by internalizing the service with the purchase, monitoring and control of continuous positive airway pressure (CPAP) equipment by the hospital.

METHODS

An observational, prospective pilot study of comparative cost analysis by internalizing the service to include all patients up to a budget limit of 5000 euros. The cost of internalizing the service included the acquisition of CPAP equipment and all the necessary accessories in addition to the nursing days necessary to track the patients. Patient satisfaction was assessed by a survey of the hospital service.

RESULTS

Twenty-one patients with 23,046 patient-days of follow-up were included. The cost of the internalized system was 6825.11 €. The cost of the outsourced system over the same period would have been 22,781.18 €; thus, the direct saving was 15,956.07 €. The cost per device per day of the internalized system was 0.30 € versus the 0.99 € that the outsourced system would have cost during the study period. In the satisfaction survey, 12 (70.6%) patients indicated that they preferred the service of the hospital over that of the external company. No patient preferred the outsourced system.

CONCLUSIONS

The internalization of CPAP service represents significant cost savings from a hospital perspective and an improvement in patients' perceptions of the quality of service.

Association of Obstructive Sleep Apnea With the Risk of Repeat Adverse Cardiovascular Events in Patients With Newly Diagnosed Acute Coronary Syndrome: A Systematic Review and Meta-Analysis

BACKGROUND

The impact of obstructive sleep apnea (OSA) on subsequent cardiovascular events in patients with acute coronary syndrome (ACS) remains inconclusive.

AIM

Our aim was to systematically assess the relationship between preexisting OSA and adverse cardiovascular events in patients with newly diagnosed ACS by conducting a systematic review and meta-analysis.

METHODS

We systematically searched PubMed, EMBASE, and Cochrane library for studies published up to May 1, 2020, that reported any association between OSA and cardiovascular events in patients with newly diagnosed ACS. The main outcomes were a composite of all-cause or cardiovascular death, recurrent myocardial infarction, stroke, repeat revascularization, or heart failure. We conducted a pooled analysis using the random-effects model. We also performed subgroup, sensitivity, heterogeneity analysis, and the assessment of publication bias.

RESULTS

We identified 10 studies encompassing 3350 participants. The presence of OSA was associated with increased risk of adverse cardiovascular events in newly prognosed ACS (risk ratio [RR] 2.18, 95% confidence interval [CI]: 1.45-3.26, P < .001, I2 = 64%). Between-study heterogeneity was partially explained by a multicenter study (9 single-center studies, RR 2.33 95% CI 1.69-3.19, I2 =18%), and I2 remarkably decreased from 64% to 18%. Moreover, OSA significantly increased the incidence of repeat revascularization (8 studies) and heart failure (6 studies) in patients with newly diagnosed ACS.

CONCLUSION

Patients with preexisting OSA are at greater risk of subsequent cardiovascular events after onset of ACS. Further studies should investigate the treatment of OSA in patient with ACS.

The Bidirectional Relationship Between Obstructive Sleep Apnea and Chronic Kidney Disease

Sleep apnea is a condition with significant health risks and increased risk of mortality and is prevalent in patients with chronic kidney disease. This paper describes the detrimental cardiovascular sequelae of sleep-disordered breathing and explores the bidirectional relationship between chronic kidney disease and obstructive sleep apnea. Obstructive sleep apnea-related hypoxia produces a range of harmful systemic effects including oxidative stress, inflammation, and sympathetic activation that collectively worsen the progression of renal disease. In turn, chronic kidney disease can result in increased severity of sleep apnea through inducing (1) uremic neuropathy and myopathy, (2) altered chemosensitivity, and (3) hypervolemia. Continuous positive airway pressure therapy remains the mainstay of treatment for reversing the health risks of apnea. Other strategies aimed at decreasing the high prevalence and associated morbidity of sleep apnea include weight loss, oral appliances, and corrective surgery in the case of airway obstruction.

Feasibility of at-home continuous overnight pulse oximetry for obstructive sleep apnea screening in bariatric surgery candidates

PURPOSE

Screening for obstructive sleep apnea (OSA) is recommended in patients scheduled for bariatric surgery because continuous positive airway pressure (CPAP) therapy in patients with moderate-to-severe OSA reduces postoperative complications. However, cardiorespiratory polygraphy (CRP) and polysomnography (PSG) are expensive and time-consuming. The present study aimed to assess whether at-home continuous overnight pulse oximetry can be used to diagnose moderate-to-severe OSA in patients scheduled for bariatric surgery.

METHODS

In this prospective observational study, we enrolled consecutive patients scheduled for bariatric surgery. Patients with no prior OSA diagnosis were evaluated using the ESS, SBQ, and preoperative at-home CRP. Correlations were calculated between AHI and oximetry parameters. For each oximetry parameter, a receiver-operating characteristic (ROC) curve was generated to identify optimal cut-off values for diagnosing moderate-to-severe OSA.

RESULTS

In total, 117 patients were included. The oxygen desaturation index was the most correlated oximetry parameter; the optimal cut-off value for diagnosing moderate-to-severe OSA was 23.9. The sensitivity and specificity were 80 and 92%, respectively. The area under the ROC curve was 0.935.

CONCLUSIONS

At-home continuous overnight pulse oximetry could be used to screen moderate-to-severe OSA in patients scheduled for bariatric surgery because it would allow clinicians to implement early CPAP therapy and avoid preoperative PSG or CRP.

The relationship between dry eye and sleep quality

PURPOSE

Sleep is an important determinant of health and quality of life. This study aimed to clarify the association between dry eye and sleep quality using a large population-based cohort.

METHODS

71,761 participants (19-94 yrs, 59.4% female) from the Lifelines cohort in the Netherlands were assessed for dry eye using the Women's Health Study Dry Eye Questionnaire. Sleep quality was evaluated using the Pittsburgh Sleep Quality Index (PSQI). Logistic regression was used to examine the relationship between poor sleep quality (PSQI score >5) and dry eye, while correcting for age, sex, BMI, education, income, and 51 possible confounding comorbidities, including autoimmune diseases and psychiatric disorders.

RESULTS

Overall, 8.9% of participants had dry eye. Of these, 36.4% had poor sleep quality compared to 24.8% of controls (OR 1.52 (95%CI 1.44-1.60), P < 0.0001, corrected for age and sex). After correcting for all comorbidities, dry eye was still associated with poor sleep (OR 1.20 (95%CI 1.11-1.28), P < 0.0001). This relationship was seen across all ages and sexes. Patients with dry eye scored worse on all subcomponents of the PSQI. Almost one-in-two (44.9%) persons with dry eye symptoms "often" or "constantly" had poor sleep quality. This proportion was similar to participants with sleep apnea and osteoarthritis. Additionally, increasing symptom frequency was tied to increased prevalence of poor sleep quality.

CONCLUSIONS

All components of sleep quality were significantly reduced in participants with dry eye, even after correcting for comorbidities. These results indicate the substantial impact of dry eye on patients' lives, especially for those with frequent symptoms.

The role of selective imidazoline receptor agonists in modern hypertension management: an international real-world survey (STRAIGHT)

BACKGROUND

Multiple pharmacologic strategies are currently available to lower blood pressure (BP). Renin-angiotensin system (RAS)-inhibitors, calcium channel blockers and diuretics are widely recommended as first line therapies. Sympathetic activation is an important contributor to BP elevation but remains unopposed or is even increased by some of these drug classes. Selective imidazoline receptor agonists (SIRAs) reduce increased central sympathetic outflow and are considered as add-on therapy in most guidelines. We conducted an international survey to evaluate contemporary hypertension management strategies in countries with high prescription rates of SIRAs to better understand the rationale and practical indications for their use in a real-world setting.

METHODS

Physicians from seven countries (India, Jordan, Lebanon, Russia, Saudi Arabia, South Africa, United Arab Emirates) were asked to complete a web-based questionnaire and comment on clinical case scenarios to provide information on their current practice regarding antihypertension strategies, underlying rationale for their choices, and adherence to relevant guidelines.

RESULTS

281 physicians completed the questionnaire including mainly cardiologists (35%) and general practitioners (32%). 96% reported using European (60%) or local (56%) guidelines in their daily practices. The majority of responding physicians (83%) had knowledge of SIRAs and 70% prescribed SIRAs regularly typically as a third line antihypertensive strategy (63%). The preferred combination partners for SIRAs were RAS-inhibitors (72%).

CONCLUSIONS

Contemporary hypertension management varies between countries and therapeutic approaches in a real-world setting are not always in line with recommendations from available guidelines. In the countries selected for this survey prescription of SIRAs was common and appeared to be guided predominantly by considerations relating to the underlying pathophysiologic mechanism of sympathetic inhibition.

Narrative review of sleep and pulmonary hypertension

Pulmonary hypertension (PH) is a condition of raised pulmonary artery pressure (PAP), which may be secondary to a number of causes, one of which is sleep disordered breathing (SDB). When PH complicates SDB, it carries a significant burden of morbidity and mortality due to the risk of progression to right ventricular failure over time. This narrative review will cover the definition and classification of PH, and explore the epidemiology of PH in SDB. The mechanisms by which the two conditions are linked will be reviewed. Repetitive hypoxia with or without hypercapnia alongside frequent arousals can result in important metabolic and pulmonary vascular consequences for the left and right heart. MEDLINE was used to search for all relevant articles and abstracts published from January 1960 to October 2019 inclusive (in all languages). Current best practice in the investigation and management of PH complicating SDB will be reviewed. Important diagnostic investigations and when to consider and screen further for PH in patients with SDB will be discussed. Optimal disease management must include control of SDB with therapy. Additional treatment options will be reviewed. Areas for further research will be highlighted.

Excessive daytime sleepiness in sleep apnea: any role of testosterone or vitamin D?

Recent studies reported association of sleep-disordered breathing (SDB) with testosterone and vitamin D deficiency. Low testosterone and vitamin D levels have been linked to fatigue and excessive daytime sleepiness (EDS). However, the impact of testosterone and vitamin D deficiency on EDS in subjects with SDB remains unknown. The aim of this study was to explore the predictors of EDS in habitual snorers. Role of testosterone, and vitamin D was studied in detail. We also looked for associations between testosterone, vitamin D, and sleep-related indices. We prospectively enrolled 291 consecutive male patients with habitual snoring. Baseline clinical characteristics were recorded on admission. Standard overnight polysomnography was performed to detect SDB, and Epworth Sleepiness Scale (ESS) was used to assess EDS. Blood samples were obtained in a fasting condition in the morning after polysomnography to determine levels of testosterone and vitamin D. Respiratory disturbance index (RDI) (95 % CI: 1.004-1.024, p=0.005) and the use of antihistamines (95 % CI: 1.083-11.901, p=0.037) were the only independent variables significantly associated with EDS in binary logistic regression analysis. In linear multiple regression analysis, body mass index (BMI) (Beta=-0.282, p<0.001) and oxygen desaturation index (Beta=-0.150, p=0.043) were the only independent variables significantly associated with testosterone levels, and BMI (Beta=-0.142, p=0.016) was the only independent variable significantly associated with vitamin D. We failed to find any independent association of testosterone and vitamin D with subjectively rated EDS among habitual snorers. Our results suggest an independent association between the magnitude of nocturnal desaturation and testosterone levels.

The Association of Sleep Disorders, Obesity and Sleep-Related Hypoxia with Cancer

BACKGROUND

Sleep disorders have emerged as potential cancer risk factors.

OBJECTIVE

This review discusses the relationships between sleep, obesity, and breathing disorders with concomitant risks of developing cancer.

RESULTS

Sleep disorders result in abnormal expression of clock genes, decreased immunity, and melatonin release disruption. Therefore, these disorders may contribute to cancer development. Moreover, in sleep breathing disorder, which is frequently experienced by obese persons, the sufferer experiences intermittent hypoxia that may stimulate cancer cell proliferation.

DISCUSSION

During short- or long- duration sleep, sleep-wake rhythm disruption may occur. Insomnia and obstructive sleep apnea increase cancer risks. In short sleepers, an increased risk of stomach cancer, esophageal squamous cell cancer, and breast cancer was observed. Among long sleepers (>9 hours), the risk of some hematologic malignancies is elevated.

CONCLUSION

Several factors including insomnia, circadian disruption, obesity, and intermittent hypoxia in obstructive sleep apnea are contributing risk factors for increased risk of several types of cancers. However, further studies are needed to determine the more significant of these risk factors and their interactions.

Intermittent hypercapnic hypoxia induces respiratory hypersensitivity to fentanyl accompanied by tonic respiratory depression by endogenous opioids

KEY POINTS

Sleep apnoea increases susceptibility to opioid-induced respiratory depression (OIRD). Endogenous opioids are implicated as a contributing factor in sleep apnoea. Rats exposed to sleep-phase chronic intermittent hypercapnic hypoxia (CIHH) for 7 days exhibited exaggerated OIRD to systemic fentanyl both while anaesthetized and artificially ventilated and while conscious and breathing spontaneously, implicating heightened CNS inhibitory efficacy of fentanyl. CIHH also induced tonic endogenous opioid suppression of neural inspiration. Sleep-related episodes of hypercapnic hypoxia, as in sleep apnoea, promote hypersensitivity to OIRD, with tonic respiratory depression by endogenous opioids implicated as a potential underlying cause.

ABSTRACT

Sleep apnoea (SA) increases opioid-induced respiratory depression (OIRD) and lethality. To test the hypothesis that this results from chronic intermittent bouts of hypercapnic hypoxia (CIHH) accompanying SA, we compared OIRD across continuously normoxic control rats and rats exposed to sleep-phase (8 h/day) CIHH for 1 week. OIRD sensitivity was first assessed in anaesthetized (urethane/α-chloralose), vagotomized and artificially ventilated rats by recording phrenic nerve activity (PNA) to index neural inspiration and quantify PNA burst inhibition to graded doses (0, 2, 20, 50 μg kg-1 , i.v.) of the synthetic opioid fentanyl. Fentanyl dose-dependently reduced PNA burst frequency (P = 0.0098-0.0001), while increasing the duration of burst quiescence at 50 μg kg-1 (P < 0.0001, n = 5-6/group/dose). CIHH shifted the fentanyl dose-phrenic burst frequency response curve to the left (P = 0.0163) and increased the duration of burst quiescence (P < 0.0001). During fentanyl recovery, PNA burst width was increased relative to baseline in normoxic and CIHH rats. Systemic naloxone (1 mg kg-1 , i.v.) reversed fentanyl-induced PNA arrest in both groups (P = 0.0002), and increased phrenic burst amplitude above baseline (P = 0.0113) in CIHH rats only. Differential sensitivity to anaesthesia as a cause of CIHH-related OIRD hypersensitivity was excluded by observing in conscious spontaneously breathing rats that fentanyl at 20 μg kg-1 (i.v.), which silenced PNA in anaesthetized rats, differentially increased breathing variability in normoxic versus CIHH rats (P = 0.0427), while significantly reducing breathing frequency (P < 0.0001) and periodicity (P = 0.0003) in CIHH rats only. Findings indicate that CIHH increased OIRD sensitivity, with tonic inspiratory depression by endogenous opioids as a likely contributing cause.

Sleep Apnea and the Kidney

Purpose of Review

There are some uncertainties about the interactions between obstructive sleep apnea (OSA) and chronic kidney disease (CKD). We critically reviewed recent studies on this topic with a focus on experimental and clinical evidence of bidirectional influences between OSA and CKD, as well as the effects of treatment of either disease.

Recent Findings

Experimental intermittent hypoxia endangers the kidneys, possibly through activation of inflammatory pathways and increased blood pressure. In humans, severe OSA can independently decrease kidney function. Treatment of OSA by CPAP tends to blunt kidney function decline over time, although its effect may vary. OSA may increase cardiovascular complications and mortality in patients with end-stage renal disease (ESRD), while it seems of little harm after renal transplantation. Excessive fluid removal may explain some of the improvements in OSA severity in ESRD and after transplantation.

Summary

Severe OSA and CKD do interact negatively, mainly through hypoxia and fluid retention. The moderate mutually interactive benefits that treatment of each disease exerts on the other one warrant further studies to improve patient management.

Complex Visceral Coupling During Central Sleep Apnea in Cats

Central sleep apnea is a sudden arrest of breathing during sleep caused by the central commands to the thoracoabdominal muscles. It is a widespread phenomenon in both healthy and diseased people, as well as in some animals. However, there is an ongoing debate whether it can be considered as a pathological deviation of the respiratory function or an adaptive mechanism of an unclear function. We performed chronic recordings from six behaving cats over multiple sleep/wake cycles, which included electroencephalogram, ECG, eye movements, air flow, and thoracic respiratory muscle movements, and in four cats combined that with the registration of myoelectric activity of the stomach and the duodenum. In these experiments, we observed frequent central cessations of breathing (for 5-13 s) during sleep. Each of the sleep apnea episodes was accompanied by a stereotypical complex of somatic and visceral effects. The heart rate increased 3-5 s before the respiration arrest and strongly decreased during the absence of respiration. The myoelectric activity of the stomach and the duodenum also often demonstrated a strong suppression during the apnea episodes. The general composition of the visceral effects was stable during all periods of observation (up to 3 years in one cat). We hypothesize that the stereotypic coupling of activities in various visceral systems during episodes of central sleep apnea most likely reflects a complex adaptive behavior rather than an isolated respiratory pathology and discuss the probable function of this phenomenon.

Sleep Stage Classification Using Time-Frequency Spectra From Consecutive Multi-Time Points

Sleep stage classification is an open challenge in the field of sleep research. Considering the relatively small size of datasets used by previous studies, in this paper we used the Sleep Heart Health Study dataset from the National Sleep Research Resource database. A long short-term memory (LSTM) network using a time-frequency spectra of several consecutive 30 s time points as an input was used to perform the sleep stage classification. Four classical convolutional neural networks (CNNs) using a time-frequency spectra of a single 30 s time point as an input were used for comparison. Results showed that, when considering the temporal information within the time-frequency spectrum of a single 30 s time point, the LSTM network had a better classification performance than the CNNs. Moreover, when additional temporal information was taken into consideration, the classification performance of the LSTM network gradually increased. It reached its peak when temporal information from three consecutive 30 s time points was considered, with a classification accuracy of 87.4% and a Cohen’s Kappa coefficient of 0.8216. Compared with CNNs, our results indicate that for sleep stage classification, the temporal information within the data or the features extracted from the data should be considered. LSTM networks take this temporal information into account, and thus, may be more suitable for sleep stage classification.

Microvascular Dysfunction in Heart Failure With Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is an increasingly studied entity accounting for 50% of all diagnosed heart failure and that has claimed its own dignity being markedly different from heart failure with reduced EF in terms of etiology and natural history (Graziani et al., 2018). Recently, a growing body of evidence points the finger toward microvascular dysfunction as the major determinant of the pathological cascade that justifies clinical manifestations (Crea et al., 2017). The high burden of comorbidities such as metabolic syndrome, hypertension, atrial fibrillation, chronic kidney disease, obstructive sleep apnea, and similar, could lead to a systemic inflammatory state that impacts the physiology of the endothelium and the perivascular environment, engaging complex molecular pathways that ultimately converge to myocardial fibrosis, stiffening, and dysfunction (Paulus and Tschope, 2013). These changes could even self-perpetrate with a positive feedback where hypoxia and locally released inflammatory cytokines trigger interstitial fibrosis and hypertrophy (Ohanyan et al., 2018). Identifying microvascular dysfunction both as the cause and the maintenance mechanism of this condition has opened the field to explore specific pharmacological targets like nitric oxide (NO) pathway, sarcomeric titin, transforming growth factor beta (TGF-β) pathway, immunomodulators or adenosine receptors, trying to tackle the endothelial impairment that lies in the background of this syndrome (Graziani et al., 2018;Lam et al., 2018). Yet, many questions remain, and the new data collected still lack a translation to improved treatment strategies. To further elaborate on this tangled and exponentially growing topic, we will review the evidence favoring a microvasculature-driven etiology of this condition, its clinical correlations, the proposed diagnostic workup, and the available/hypothesized therapeutic options to address microvascular dysfunction in the failing heart.

Effect of Heart Rate Variability on the Association Between the Apnea-Hypopnea Index and Cerebral Small Vessel Disease

Background and Purpose- The apnea-hypopnea index (AHI) is associated with cerebral small vessel disease (cSVD), but pathogenesis of this association is elusive. We aimed to assess the effect of nighttime heart rate variability (HRV)-as a proxy of sympathetic upregulation-on the aforementioned association. Methods- Atahualpa residents aged ≥60 years undergoing brain magnetic resonance imaging, polysomnography, and 24-hour Holter monitoring (N=176) were included. The presence of moderate-to-severe white matter hyperintensities, deep cerebral microbleeds, lacunar infarcts, and >10 enlarged basal ganglia perivascular spaces were added for estimating the cSVD score. Interaction models were fitted to assess the effect modification of nighttime HRV in the association between the AHI and the cSVD score, and mediation analysis was utilized to assess the proportion of total effect by nighttime HRV on this association. Results- Generalized linear models showed a significant association between the AHI and the cSVD score (P=0.025), as well as a significant inverse association between nighttime HRV and the cSVD score (P=0.002), but no association between daytime HRV and the cSVD score (P=0.097). Interaction models showed a significant interaction of nighttime HRV on the association between AHI and the cSVD score (P=0.001), and mediation analysis found that the percent of total effect between AHI and cSVD score mediated by HRV was 30.8%. Predictive marginal means of the cSVD score were highly significant when the 10th percentile of nighttime HRV was compared across categories of 10th and 90th percentiles of the AHI (cSVD score margins, 0.61 [95% CI, 0.37-0.86] versus 1.67 [95% CI, 1.26-2.09]). Contour plots showed the effect of nighttime (but not daytime) HRV on the association between AHI and the cSVD score. Conclusions- This study shows an important effect of nighttime HRV on the association between the AHI and the cSVD score and provides further support for the role of sympathetic overactivity on this association.

Prognostic impact of residual SYNTAX score in patients with obstructive sleep apnea and acute coronary syndrome: a prospective cohort study

Background

There is a paucity of data from large prospective study evaluating the prognostic significance of the residual Synergy between percutaneous intervention with Taxus drug-eluting stents and cardiac surgery (SYNTAX) Score (rSS) in patients with obstructive sleep apnea (OSA) and Acute Coronary Syndrome (ACS).

Methods

ACS patients who undergoing percutaneous coronary angiography and completing a sleep study during hospitalization were prospectively enrolled. The baseline SYNTAX Score (bSS) and the rSS after revascularization were assessed. Complete revascularization (CR, rSS = 0) and incomplete revascularization (ICR, rSS > 0) were categorized. OSA (apnea hypopnea index, AHI ≥ 15) and non-OSA (AHI < 15) were grouped according to AHI. The primary endpoint of the study was major adverse cardiovascular and cerebrovascular events (MACCEs), defined as a composite of cardiovascular death, myocardial infarction, stroke, ischemia-driven revascularization, or hospitalization for UAP or heart failure.

Results

Overall, 752 patients were prospectively enrolled. At a median follow-up of 1 year, the incidence of MACCEs was significantly higher in the OSA than in the non-OSA group (hazard ratio [HR]:1.68; 95% confidence interval [CI]:1.04–2.72; P = .034). ICR was associated with a higher risk of MACCEs in the non-OSA group (HR:3.34;95% CI:1.0–11.12; P = .05). The OSA patients with ICR had a 5.1 higher risk of MACCEs compared with the non-OSA with CR group, P = .007. The OSA patients with CR had a similar 1-year MACCEs as all the non-OSA patients (HR:1.10; 95% CI:0.515–2.349; P = 0.806).

Conclusions

ACS patients with OSA and ICR have a high rate of MACCEs at 1 year. In contrast, the prognosis of ACS patients with OSA but CR is favorable and similar to patients without OSA. Adequate level of revascularization is recommended to optimize clinical outcomes in ACS patients with OSA.

Trial registration

Clinicaltrials.gov identifier NCT03362385.

Sleep apnea and galectin-3: possible sex-specific relationship

PURPOSE

Sleep apnea is associated with increased risk of cardiovascular disease. Elevated plasma galectin-3 levels, a biomarker associated with myocardial fibrosis, are also associated with adverse cardiovascular events, including heart failure. Our objective was to determine the relationship between severity of sleep apnea and plasma levels of galectin-3 and to determine whether this relationship was modified by sex.

METHODS

We performed a cross-sectional study of 471 Mexican Americans from Starr County, TX who underwent an overnight, in-home sleep evaluation, and plasma measurement of galectin-3. Severity of sleep apnea was based on apnea hypopnea index (AHI). Multivariable linear regression modeling was used to determine the association between categories of sleep apnea and galectin-3. We also tested for interactions by sex.

RESULTS

The mean age was 53 years, and 74% of the cohort was female. The prevalence of moderate to severe sleep apnea (AHI > 15 apnea-hypopnea events per hour) was 36.7%. Moderate to severe sleep apnea was associated with increased levels of galectin-3 in the entire population, but we identified a statistically significant interaction between galectin-3 levels and category of sleep apnea by sex (p for interaction = 0.02). Plasma galectin levels were significantly higher in women with moderate or severe sleep apnea than women with no/mild sleep apnea (multivariable adjusted p < 0.001), but not in men (p = 0.5).

CONCLUSIONS

Sleep apnea is associated elevated galectin-3 levels in women but not men. Our findings highlight a possible sex-specific relationship between sleep apnea and galectin-3, a biomarker of potential myocardial fibrosis that has been associated with increased cardiovascular risk.

Alteraciones del sueño más frecuentes en las personas en diálisis

Introducción: La persona con enfermedad renal crónica en terapia dialítica presenta alteraciones en diferentes dimensiones de su vida, entre ellos el sueño, considerado una de las necesidades biológicas más importantes del organismo. Objetivo: Conocer las principales alteraciones del sueño en pacientes con ERC en tratamiento dialítico, los factores que influyen en su aparición y cuidados de enfermería. Metodología: Revisión narrativa de la literatura. Los criterios de inclusión fueron estudios primarios y revisiones sistemáticas, tanto cualitativos como cuantitativos, sobre alteraciones del sueño en pacientes adultos con ERC en terapia dialítica. Se consultaron las bases de datos Medline, Scielo y Epistemonikos. Resultados: La prevalencia de trastornos del sueño es alta en personas con enfermedad renal crónica que se someten a diálisis, las principales son síndrome de piernas inquietas y síndrome de apnea obstructiva del sueño. En el primero, el principal factor causal es el déficit de hierro y disfunción de dopamina, mientras que en el segundo son la sobrecarga de volumen y estrechez de vías respiratorias. El manejo responde a medidas farmacológicas como administración de hierro, agentes dopaminérgicos y uso de CPAP, además de medidas no farmacológicas que son transversales a ambos, como higiene del sueño. Conclusión: Las alteraciones del sueño en los pacientes en diálisis claramente repercuten en su calidad de vida, por lo que es un aspecto en que los profesionales de salud debiesen adquirir conocimientos y otorgar cuidados de enfermería específicos para prevenir, atenuar síntomas y evitar complicaciones.

Opportunities for utilizing polysomnography signals to characterize obstructive sleep apnea subtypes and severity

BACKGROUND

Obstructive sleep apnea (OSA) is a heterogeneous sleep disorder with many pathophysiological pathways to disease. Currently, the diagnosis and classification of OSA is based on the apnea-hypopnea index, which poorly correlates to underlying pathology and clinical consequences. A large number of in-laboratory sleep studies are performed around the world every year, already collecting an enormous amount of physiological data within an individual. Clinically, we have not yet fully taken advantage of this data, but combined with existing analytical approaches, we have the potential to transform the way OSA is managed within an individual patient. Currently, respiratory signals are used to count apneas and hypopneas, but patterns such as inspiratory flow signals can be used to predict optimal OSA treatment. Electrocardiographic data can reveal arrhythmias, but patterns such as heart rate variability can also be used to detect and classify OSA. Electroencephalography is used to score sleep stages and arousals, but specific patterns such as the odds-ratio product can be used to classify how OSA patients responds differently to arousals.

OBJECTIVE

In this review, we examine these and many other existing computer-aided polysomnography signal processing algorithms and how they can reflect an individual's manifestation of OSA.

SIGNIFICANCE

Together with current technological advance, it is only a matter of time before advanced automatic signal processing and analysis is widely applied to precision medicine of OSA in the clinical setting.

Sleep and Circadian Hygiene and Inflammatory Bowel Disease

There is increasing evidence that sleep and circadian disruption can worsen the disease course in inflammatory bowel disease (IBD). Sleep and circadian disruption are prevalent in society and are associated with worse outcomes in IBD. Emerging research suggests sleep and circadian disruption can impact key components in IBD disease flares, including intestinal permeability, translocation of bacterial endotoxins, intestinal dysbiosis, and proinflammatory cytokines. Much of this research has been conducted in animal models. There is a clear need for large randomized controlled trials in human patients with IBD, where the potential for chronotherapeutic strategies to improve disease course can be tested.