Prevalence of sleep-disordered breathing after stroke and TIA: A meta-analysis

Positive Airway Pressure Therapy in Sleep-Disordered Breathing

Obstructive sleep apnea (OSA) is a highly prevalent condition with major neurocognitive and cardiovascular health effects. Positive airway pressure (PAP) therapy prevents the collapse of the pharyngeal airway to improve hypoxemia, hypercapnia, and sleep fragmentation caused by OSA. While adherence to PAP therapy has been thought to be a barrier to use, consistent usage is likely much higher than commonly thought. In addition, many strategies have been developed to assist providers in improving their patients' PAP adherence.

Neural network analysis of nocturnal SpO2 signal enables easy screening of sleep apnea in patients with acute cerebrovascular disease

Current diagnostics of sleep apnea relies on the time-consuming manual analysis of complex sleep registrations, which is impractical for routine screening in hospitalized patients with a high probability for sleep apnea, e.g. those experiencing acute stroke or transient ischemic attacks (TIA). To overcome this shortcoming, we aimed to develop a convolutional neural network (CNN) capable of estimating the severity of sleep apnea in acute stroke and TIA patients based solely on the nocturnal oxygen saturation (SpO₂) signal. The CNN was trained with SpO₂ signals derived from 1379 home sleep apnea tests (HSAT) of suspected sleep apnea patients and tested with SpO₂ signals of 77 acute ischemic stroke or TIA patients. The CNN's performance was tested by comparing the estimated respiratory event index (REI) and oxygen desaturation index (ODI) with manually obtained values. Median estimation errors for REI and ODI in patients with stroke or TIA were 1.45 events/hour and 0.61 events/hour, respectively. Furthermore, based on estimated REI and ODI, 77.9% and 88.3% of these patients were classified into the correct sleep apnea severity categories. The sensitivity and specificity to identify sleep apnea (REI > 5 events/hour) were 91.8% and 78.6%, respectively. Moderate-to-severe sleep apnea was detected (REI > 15 events/hour) with sensitivity of 92.3% and specificity of 96.1%. The CNN analysis of the SpO₂ signal has great potential as a simple screening tool for sleep apnea. This novel automatic method accurately detects sleep apnea in acute cerebrovascular disease patients and facilitates their referral for a differential diagnostic HSAT or polysomnography evaluation.

Trials in Sleep Apnea and Stroke: Learning From the Past to Direct Future Approaches

Few randomized controlled trials have evaluated the effectiveness of continuous positive airway pressure (CPAP) in reducing recurrent vascular events and mortality in poststroke obstructive sleep apnea (OSA). To date, results have been mixed, most studies were underpowered and definitive conclusions are not available. Using lessons learned from prior negative trials in stroke, we reappraise prior randomized controlled trials that examined the use of CPAP in treating poststroke OSA and propose the following considerations: (1) Intervention-based changes, such as ensuring that patients are using CPAP for at least 4 hours per night (eg, through use of improvements in CPAP technology that make it easier for patients to use), as well as considering alternative treatment strategies for poststroke OSA; (2) Population-based changes (ie, including stroke patients with severe and symptomatic OSA and CPAP noncompliers); and (3) Changes to timing of intervention and follow-up (ie, early initiation of CPAP therapy within the first 48 hours of stroke and long-term follow-up calculated in accordance with sample size to ensure adequate power). Given the burden of vascular morbidity and mortality in stroke patients with OSA, there is a strong need to learn from past negative trials and explore innovative stroke prevention strategies to improve stroke-free survival.

Sleep apnea prediction in acute ischemic stroke (SLAPS score): a derivation study

BACKGROUND

Despite its high prevalence and negative impact, sleep-disordered breathing (SDB) remain commonly underdiagnosed and undertreated in stroke subjects. Multiple stroke comorbidities and risk factors, including obesity, hypertension, diabetes mellitus, ischemic heart disease, atrial fibrillation, and heart failure (H.F.) have been associated with SDB. This study aimed to examine associations of clinical and demographic characteristics with moderate-to-severe SDB (msSDB) in stroke patients and to develop a predictive score.

METHODS

Consecutive patients with ischemic stroke were enrolled in an open, prospective study. SDB was assessed using standard polysomnography. Clinical and demographic characteristics, as well as findings from echocardiography, entered the analysis. Multivariate logistic regression models were used to examine the associations with msSDB. Based on the results, an original score to predict msSDB was proposed and tested.

RESULTS

120 patients with acute ischemic stroke (mean age: 64.0 ± 12.2 years, median NIHSS: 4) were included. Body-mass index (BMI), wake-up stroke onset (WUS), and diastolic dysfunction were independently associated with msSDB. A score allocating 1 point for BMI≥25 kg/m² and <30 kg/m², 2 points for BMI≥30 kg/m², 1 point for WUS and 1 point for diastolic dysfunction resulted in an area under the curve of 0.81 (95% CI 0.71-0.90, p<0.001), sensitivity 82.9%, specificity 71.9% to identify stroke patients with msSDB.

CONCLUSIONS

BMI, WUS, and diastolic dysfunction were associated with msSDB. A simple score might help to identify acute stroke patients with msSDB, who are usual candidates for positive airway pressure therapy.

SAS CARE 2 - a randomized study of CPAP in patients with obstructive sleep disordered breathing following ischemic stroke or transient ischemic attack

Objective/background

The benefit of Continuous Positive Airway Pressure (CPAP) treatment following ischemic stroke in patients with obstructive sleep-disordered breathing (SDB) is unclear. We set out to investigate this open question in a randomized controlled trial as part of the SAS-CARE study.

Patients/methods.

Non-sleepy patients (ESS < 10) with ischemic stroke or transient ischemic attack (TIA) and obstructive SDB (AHI ≥ 20) 3 months post-stroke were randomized 1:1 to CPAP treatment (CPAP+) or standard care. Primary outcome was the occurrence of vascular events (TIA/stroke, myocardial infarction/revascularization, hospitalization for heart failure or unstable angina) or death within 24 months post-stroke. Secondary outcomes included Modified Rankin Scale (mRS) and Barthel Index.

Results

Among 238 SAS-CARE patients 41 (17%) non-sleepy obstructive SDB patients were randomized to CPAP (n = 19) or standard care (n = 22). Most patients (80%) had stroke and were males (78%), mean age was 64 ± 7 years and mean NIHSS score 0.6 ± 1.0 (range: 0–5). The primary endpoint was met by one patient in the standard care arm (a new stroke). In an intent-to treat analysis disregarding adherence, this corresponds to an absolute risk difference of 4.5% or an NNT = 22. mRS and Barthel Index were stable and similar between arms. CPAP adherence was sufficient in 60% of evaluable patients at month 24.

Conclusion

No benefit of CPAP started three months post-stroke was found in terms of new cardio- and cerebrovascular events over 2 years. This may be related to the small size of this study, the mild stoke severity, the exclusion of sleepy patients, the delayed start of treatment, and the overall low event rate.

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No benefit of CPAP started 3 months post-stroke was found.

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A sufficient CPAP compliance was observed over 2 years in 60% of patients.

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Studies of CPAP in mild stroke need to be large and include long-term outcomes.

Central sleep apnea is uncommon after stroke

OBJECTIVE/BACKGROUND

Stroke is often considered a risk factor for central sleep apnea (CSA). The goal of this study was to determine the prevalence and clinical correlates of CSA in patients with ischemic stroke.

PATIENTS/METHODS

In this analysis, 1346 participants in the Brain Attack Surveillance in Corpus Christi (BASIC) project underwent a home sleep apnea test shortly after ischemic stroke. Respiratory events during sleep were classified as central apneas, obstructive apneas, or hypopneas. Central apnea index (CAI) was defined as number of central apneas divided by recording time. CSA was defined as CAI ≥5/hour with at least 50% of all scored respiratory events classified as central apneas. Demographics and co-morbidities were ascertained from the medical record.

RESULTS

Median CAI was 0/hour. Nineteen participants (1.4%) met criteria for CSA. Participants with CSA were more likely to be male, and had lower prevalence of obesity than participants without CSA. There was no association between CSA and other co-morbidities.

CONCLUSIONS

CSA was uncommon in this large cohort of patients with recent ischemic stroke.

Imaging of sleep-disordered breathing in adults

Sleep-disordered breathing (SDB) is a term that includes several chronic conditions in which partial or complete cessation of breathing occurs multiple times throughout the night. Central sleep apnoea (CSA) is uncommon and defined by the episodic cessation of airflow without respiratory effort. Lesions involving the respiratory centre in the brainstem or the origin of the phrenic nerve from the mid-cervical cord are the commonest structural causes of CSA; magnetic resonance imaging (MRI) will demonstrate the lesion and frequently suggest the likely aetiology. In contrast, obstructive sleep apnoea (OSA) is defined as upper airway obstruction despite ongoing respiratory effort. Repetitive episodes of narrowing or closure of the upper airway are the predominant cause leading to snoring and OSA, respectively. OSA affects 33-40% of the adult population and is associated with multiple adverse health consequences, including a significantly increased risk of serious morbidity and mortality. The incidence is increasing proportionally to the worldwide rise in obesity. Imaging, performed primarily without the involvement of radiologists, has been integral to understanding the anatomical basis of SDB and especially OSA. This article will review the pathophysiology, imaging findings, and sequelae of these common conditions. The role of imaging both in suggesting the incidental diagnoses of SDB and in the investigation of these conditions when the diagnosis is suspected or has been established are also discussed.

SAS Care 1: sleep-disordered breathing in acute stroke an transient ischaemic attack - prevalence, evolution and association with functional outcome at 3 months, a prospective observational polysomnography study

Sleep-disordered breathing (SDB) is frequent in patients with acute stroke. Little is known, however about the evolution of SDB after stroke. Most of our knowledge stems from smaller cohort studies applying limited cardiopulmonary sleep recordings or from cross-sectional data collected in different populations.

This study aims to determine prevalence, type and intra-individual evolution of SDB based on full-night polysomnography (PSG) in acute stroke and 3 months thereafter. Furthermore, we aimed to identify predictors of SDB in the acute and chronic phase and to evaluate associations between SDB and functional outcome at 3 months (M3).

A total of 166 patients with acute cerebrovascular events were evaluated by full PSG at baseline and 105 again at M3. The baseline prevalence of SDB (apnoea–hypopnoea index (AHI)>5·h⁻¹) was 80.5% and 25.4% of the patients had severe SDB (AHI>30·h⁻¹). Obstructive sleep apnoea was more prevalent than central sleep apnoea (83.8% versus 13%). Mean±SD AHI was 21.4±17.6·h⁻¹and decreased significantly at M3 (18±16.4·h⁻¹; p=0.018). At M3, 91% of all patients with baseline SDB still had an AHI>5·h⁻¹ and in 68.1% the predominant type of SDB remained unchanged (78.9% in obstructive sleep apnoea and 44.4% in central sleep apnoea). The only predictors of SDB at baseline were higher age and body mass index and in the chronic phase additionally baseline AHI. Baseline AHI was associated with functional outcome (modified Rankin score >3) at M3.

The high prevalence of SDB in acute stroke, its persistence after 3 months, and the association with functional outcome supports the recommendation for a rapid SDB screening in stroke patients.

The high prevalence of SDB in acute stroke, its persistence after 3 months and its association with functional outcome support the recommendation for rapid SDB screening in stroke patientshttps://bit.ly/3bFWqV7

Prediction of sleep-disordered breathing after stroke

OBJECTIVE/BACKGROUND

Sleep-disordered breathing (SDB) is highly prevalent after stroke and is associated with poor outcomes. Currently, after stroke, objective testing must be used to differentiate patients with and without SDB. Within a large, population-based study, we evaluated the usefulness of a flexible statistical model based on baseline characteristics to predict post-stroke SDB.

PATIENTS/METHODS

Within a population-based study, participants (2010-2018) underwent SDB screening, shortly after ischemic stroke, with a home sleep apnea test. The respiratory event index (REI) was calculated as the number of apneas and hypopneas per hour of recording; values ≥10 defined SDB. The distributed random forest classifier (a machine learning technique) was applied to predict SDB with the following as predictors: demographics, stroke risk factors, stroke severity (NIHSS), neck and waist circumference, palate position, and pre-stroke symptoms of snoring, apneas, and sleepiness.

RESULTS

Within the total sample (n = 1330), median age was 65 years; 47% were women; 32% non-Hispanic white, 62% Mexican American, and 6% African American. SDB was found in 891 (67%). The area under the receiver operating characteristic curve, a measure of predictive ability, applied to the validation sample was 0.75 for the random forest model. Random forest correctly classified 72.5% of validation samples.

CONCLUSIONS

In this large, ethnically diverse, population-based sample of ischemic stroke patients, prediction models based on baseline characteristics and clinical measures showed fair rather than clinically reliable performance, even with use of advanced machine learning techniques. Results suggest that objective tests are still needed to differentiate ischemic stroke patients with and without SDB.

EAN/ERS/ESO/ESRS statement on the impact of sleep disorders on risk and outcome of stroke

Sleep disorders are highly prevalent in the general population and may be linked in a bidirectional fashion to stroke, which is one of the leading causes of morbidity and mortality.Four major scientific societies established a task force of experts in neurology, stroke, respiratory medicine, sleep medicine and methodology, to critically evaluate the evidence regarding potential links and the impact of therapy. 13 research questions were evaluated in a systematic literature search using a stepwise hierarchical approach: first, systematic reviews and meta-analyses; second, primary studies post-dating the systematic reviews/meta-analyses. A total of 445 studies were evaluated and 88 included. Statements were generated regarding current evidence and clinical practice.Severe obstructive sleep apnoea (OSA) doubles the risk for incident stroke, especially in young to middle-aged patients. Continuous positive airway pressure (CPAP) may reduce stroke risk, especially in treatment-compliant patients. The prevalence of OSA is high in stroke patients and can be assessed by polygraphy. Severe OSA is a risk factor for recurrence of stroke and may be associated with stroke mortality, while CPAP may improve stroke outcome. It is not clear if insomnia increases stroke risk, while pharmacotherapy of insomnia may increase it. Periodic limb movements in sleep (PLMS), but not restless limb syndrome (RLS), may be associated with an increased risk of stroke. Preliminary data suggest a high frequency of post-stroke insomnia and RLS and their association with a less favourable stroke outcome, while treatment data are scarce.Overall, the evidence base is best for OSA relationship with stroke and supports active diagnosis and therapy. Research gaps remain especially regarding insomnia and RLS/PLMS relationships with stroke.

Diagnosis and Management of Obstructive Sleep Apnea: A Review

IMPORTANCE

Obstructive sleep apnea (OSA) affects 17% of women and 34% of men in the US and has a similar prevalence in other countries. This review provides an update on the diagnosis and treatment of OSA.

OBSERVATIONS

The most common presenting symptom of OSA is excessive sleepiness, although this symptom is reported by as few as 15% to 50% of people with OSA in the general population. OSA is associated with a 2- to 3-fold increased risk of cardiovascular and metabolic disease. In many patients, OSA can be diagnosed with home sleep apnea testing, which has a sensitivity of approximately 80%. Effective treatments include weight loss and exercise, positive airway pressure, oral appliances that hold the jaw forward during sleep, and surgical modification of the pharyngeal soft tissues or facial skeleton to enlarge the upper airway. Hypoglossal nerve stimulation is effective in select patients with a body mass index less than 32. There are currently no effective pharmacological therapies. Treatment with positive airway pressure lowers blood pressure, especially in patients with resistant hypertension; however, randomized clinical trials of OSA treatment have not demonstrated significant benefit on rates of cardiovascular or cerebrovascular events.

CONCLUSIONS AND RELEVANCE

OSA is common and the prevalence is increasing with the increased prevalence of obesity. Daytime sleepiness is among the most common symptoms, but many patients with OSA are asymptomatic. Patients with OSA who are asymptomatic, or whose symptoms are minimally bothersome and pose no apparent risk to driving safety, can be treated with behavioral measures, such as weight loss and exercise. Interventions such as positive airway pressure are recommended for those with excessive sleepiness and resistant hypertension. Managing asymptomatic OSA to reduce cardiovascular and cerebrovascular events is not currently supported by high-quality evidence.

ERS International Congress, Madrid, 2019: highlights from the Sleep and Clinical Physiology Assembly

The 2019 European Respiratory Society (ERS) International Congress took place in Madrid, Spain, and served as a platform to find out the latest advances in respiratory diseases research. The research aims are to understand the physiology and consequences of those diseases, as well as the improvement in their diagnoses, treatments and patient care. In particular, the scientific sessions arranged by ERS Assembly 4 provided novel insights into sleep-disordered breathing and new knowledge in respiratory physiology. This article, divided by session, will summarise the most relevant studies presented at the ERS International Congress. Each section has been written by Early Career Members specialising in the different fields of this interdisciplinary assembly.

Diagnostic Accuracy of Positive Airway Pressure Device for Sleep Apnea Detection in Acute Stroke Patients

Background and Purpose—

Sleep apnea has been associated with a poor outcome in acute stroke patients. Polysomnography is the gold standard diagnostic method for sleep apnea, but it is not feasible as a routine in the acute stroke setting. The current generation of positive airway pressure (PAP) devices can detect the different types of respiratory events. This study aimed to compare the algorithms used in PAP device to manually scored events on polysomnography in patients with acute stroke.

Methods—

A sleep study was performed with standard polysomnography and PAP device, simultaneously, within the first 48 hours after acute stroke onset.

Results—

We prospectively evaluated 29 patients with acute stroke (59.5±12.1 years). The area under the receiver operating characteristic curve for each apnea-hypopnea index value was above 0.90 by PAP device. There was a good correlation of apnea-hypopnea index ( r s =0.92; P <0.001), hypopnea index ( r s =0.89; P <0.001), and apnea index ( r s =0.70; P <0.001) between device-detected events and manually scored polysomnography.

Conclusions—

Given the high frequency of sleep apnea during the acute phase of stroke and the complexity of a full polysomnography study in this setting, PAP device on diagnostic mode can be used as an alternative tool for sleep apnea detection in acute stroke patients.

Adult obstructive sleep apnoea: Pathogenesis, importance, diagnosis and imaging

Obstructive sleep apnoea (OSA) is a serious worldwide health problem. Moderate-to-severe OSA has been found in up to 50% of men and 25% of women in the middle-aged population. It results in a fourfold increase in all causes of mortality. The prevalence of OSA is underestimated, partly due to absence of symptoms but also lack of knowledge amongst the population at large as well as sectors of the medical profession. Imaging, performed predominantly by clinicians and research scientists, has been integral to evaluating the anatomical basis of OSA. Increased nasal resistance and a narrowed and elongated oropharynx lead to increased collapsibility of the upper airway, predisposing to airway collapse and apnoea during sleep when there is reduction in tone of the pharyngeal dilator muscles. Unfortunately, a significantly narrowed upper airway is usually ignored by radiologists: it is not part of their reporting 'check-list'. The imaging findings in the upper airway that are strongly associated with OSA and its sequelae in various organ systems are discussed. Imaging can strongly suggest OSA; the diagnosis requires a polysomnogram for confirmation. Treatment of moderate-to-severe disease is primarily with positive airway pressure applied by a nasal or oral mask which splints the upper airway. Although highly effective, compliance is limited and other treatment modalities are increasingly being utilized.

Sleep Apnea and Early Neurological Deterioration in Acute Ischemic Stroke

BACKGROUND AND PURPOSE

Evidence of an association between sleep apnea (SA) and early neurological deterioration (END) in acute phase ischemic stroke is scant. We investigated the prevalence of SA and the impact of SA severity on END in acute ischemic stroke (AIS) patients.

METHODS

We prospectively enrolled consecutive AIS patients admitted to our stroke unit within 72 hours of symptom onset. SA severity was assessed with ApneaLink-a validated portable respiratory monitor. SA was defined as an apnea-hypopnea index (AHI) of greater than or equal to 5 per hour. END was defined as an incremental increase in the National Institutes of Health Stroke Scale (NIHSS) score by greater than or equal to 1 point in motor power, or greater than or equal to 2 points in the total score within the first week after admission.

RESULTS

Of the 305 patients studied, 254 (83.3%) patients had SA (AHI ≥ 5 per hour), and of these, 114 (37.4%) had mild SA (AHI 5-14 per hour), 59 (19.3%) had moderate SA (AHI 15-29 per hour), and 81 (26.6%) had severe SA (AHI ≥ 30 per hour). Thirty-six (11.8%) patients experienced END: 2 of the 51 (3.9%) patients without SA and 34 of the 254 (14.4%) patients with SA. Multivariable regression analysis showed AHI independently predicted END (odds ratio 1.024; 95% confidence interval 1.006 to 1.042; P = .008).

CONCLUSIONS

SA is common in the acute phase of ischemic stroke, and SA severity is associated with the risk of END.

Sleep and brain morphological changes in the eighth decade of life

OBJECTIVE

Sleep is important for brain health. We analysed associations between usual sleep habits and magnetic resonance imaging (MRI) markers of neurodegeneration (brain atrophy), vascular damage (white matter hyperintensities, WMH) and waste clearance (perivascular spaces, PVS) in older community-dwelling adults.

METHOD

We collected self-reported usual sleep duration, quality and medical histories from the Lothian Birth Cohort 1936 (LBC1936) age 76 years and performed brain MRI. We calculated sleep efficiency, measured WMH and brain volumes, quantified PVS, and assessed associations between sleep measures and brain markers in multivariate models adjusted for demographic and medical history variables.

RESULTS

In 457 subjects (53% males, mean age 76 ± 0.65 years), we found: brain and white matter loss with increased weekend daytime sleep (β = -0.114, P = 0.03; β = -0.122, P = 0.007 respectively), white matter loss with less efficient sleep (β = 0.132, P = 0.011) and PVS increased with interrupted sleep (OR 1.84 95% CI, P = 0.025).

CONCLUSION

Cross-sectional associations of sleep parameters with brain atrophy and more PVS suggest adverse relationships between usual sleep habits and brain health in older people that should be evaluated longitudinally.

Sleep-Disordered Breathing and Idiopathic Normal-Pressure Hydrocephalus: Recent Pathophysiological Advances

Purpose of Review

Idiopathic normal-pressure hydrocephalus (iNPH) is characterized clinically by ventriculomegaly, abnormal gait, falls, incontinence, and cognitive decline. This article reviews recent advances in the pathophysiology of iNPH concerning sleep-disordered breathing (SDB) and glymphatic circulation during deep sleep.

Recent Findings

The authors found iNPH frequently associated with obstructive sleep apnea (OSA). A critical factor in iNPH is intracranial venous hypertension delaying drainage of cerebrospinal fluid (CSF) into the cerebral venous sinuses. CSF-venous blood circulates in the jugular veins and finally drains into the heart. During SDB, repeated reflex attempts to breathe induce strong respiratory efforts against a closed glottis thereby increasing the negative intrathoracic pressure. This causes atrial distortion and decreases venous return to the heart resulting in retrograde intracranial venous hypertension. Additionally, repeated awakenings from OSA impede sleep-associated circulation of interstitial CSF into the glymphatic circulation contributing to hydrocephalus.

Summary

Sleep has become a critical element in the cognitive changes of aging including iNPH.