Effect of upper airway obstruction in acute stroke on functional outcome at 6 months

From Molecular to Clinical Implications of Sleep-Related Breathing Disorders on the Treatment and Recovery of Acute Stroke: A Scoping Review

(1) Background: The aim of this review is to map research into the molecular mechanisms linking sleep-related breathing disorders (SRBDs) and acute stroke and their clinical and therapeutic implications and to identify existing knowledge gaps to suggest new areas of research. (2) Methods: This review was conducted according to the PRISMA extension for scoping reviews (PRISMA-ScR) and a predetermined protocol shared among all authors. (3) Results: The review of the thirteen studies analyzed provides a focused view of the molecular features about interaction between obstructive sleep apnea (OSA) and acute stroke. Our review identifies and highlights the biomarkers most frequently found to be associated with acute stroke, SRBDs, and their clinical repercussions. (4) Conclusions: The association between the presence of sleep apnea, especially in its severe form, and elevated levels of inflammatory markers in patients with acute stroke is highlighted and new research topics in this area are proposed.

Changes in sleep-disordered breathing severity and post-stroke outcomes in the first year after stroke

BACKGROUND

Sleep-disordered breathing (SDB) is common among stroke survivors and is associated with worse functional, cognitive, and neurologic outcomes after stroke. Little is known about the association between changes in SDB and changes in these outcomes over time.

METHODS

Ischemic stroke (IS) patients identified through the Brain Attack Surveillance in Corpus Christi project were offered SDB testing with a portable respiratory monitor (ApneaLink Plus) shortly after stroke, and at 3-, 6-, and 12-months post-stroke. SDB was quantified using the respiratory event index (REI; apneas plus hypopneas per hour of recording). At 3-, 6-, and 12-months post-stroke, functional outcomes, cognitive outcomes, and neurologic outcomes were measured. Linear mixed models were fitted to obtain random slopes reflecting individual changes in REI and each of outcome over time, adjusted for multiple covariates. Associations between the resulting individual slopes for REI and each outcome were then evaluated using linear regression models.

RESULTS

Of 482 IS patients with at least one REI measurement, in fully adjusted models, faster reduction in REI was not associated with faster improvement in functional (β = -0.06; 95 % CI: -0.15, 0.03, p = 0.16), cognitive (β = -0.03; 95 % CI: -0.12, 0.06, p = 0.51), or neurologic outcomes (β = -0.04; 95 % CI: -0.13, 0.05, p = 0.41).

CONCLUSIONS

In this observational study of stroke survivors, there was no clear association between the rate of improvement in SDB and improvement in functional, cognitive, or neurologic outcomes. It remains to be seen whether treatment of SDB might lead to improved outcomes among stroke survivors.

Real world challenges and barriers for positive airway therapy use in acute ischemic stroke patients

PURPOSE

Untreated obstructive sleep apnea (OSA) in patients with acute ischemic stroke (AIS) is associated with increased morbidity and mortality. However, diagnosing and treating OSA in AIS is challenging. We aimed to determine the feasibility of portable monitoring (PM) for diagnosis and positive airway pressure therapy for treatment of OSA in an inpatient stroke population.

METHODS

We recruited inpatients with AIS from Cleveland Clinic. Those who consented underwent PM; participants with a respiratory event index (REI) ≥ 10 were offered auto-titrating positive airway pressure therapy (APAP). Ease-of-use questionnaires were completed. We summarized categorical variables using n(%) and continuous variables using mean ± SD or median [IQR].

RESULTS

27 participants (age 59.8 ± 11.8, 51.9% female, 51.9% Black, BMI 33.4 ± 8.5) enrolled. The study ended early due to Medicare contracting that forced most patients to complete stroke rehabilitation outside the Cleveland Clinic health system. 59.3% had large vessel occlusions and 53.8% had moderate/severe disability (Modified Rankin score ≥ 2). PM was attempted in 21 participants, successful in 18. Nurses and patients rated the PM device as highly easy to use. 13 of 18 (72%) patients who had an REI ≥ 10 consented to APAP titration, but only eight (61.5%) of those 13 used APAP for more than one night, and only five (27.8%) used APAP up to 90 days with data captured for only one participant. Five required troubleshooting at titration, and only one had adherent APAP usage by objective assessment after discharge.

CONCLUSIONS

This study demonstrates the real-world challenges of assessing and treating OSA in an AIS population, highlighting the necessity for further research into timely and feasible screening and treatment.

Early screening of sleep disordered breathing in hospitalized stroke patients high-resolution pulse oximetry as prognostic and early intervention tools in patients with acute stroke and sleep apnea (HOPES TRIAL)

INTRODUCTION

Sleep Disordered Breathing (SDB) has been shown to increase the risk of stroke and despite recommendations, routine evaluation for SDB in acute stroke is not consistent across institutions. The necessary logistics and expertise required to conduct sleep studies in hospitalized patients remain a significant barrier. This study aims to evaluate the feasibility of high-resolution pulse-oximetry (HRPO) for the screening of SDB in acute stroke. Secondarily, considering impact of SDB on acute stroke, we investigated whether SDB at acute stroke predicts functional outcome at discharge and at 3 months post-stroke.

METHODS

Patients with acute mild to moderate ischemic stroke underwent an overnight HRPO within 48 h of admission. Patients were divided into SDB and no-SDB groups based on oxygen desaturations index(ODI > 10/h). Stepwise multivariate logistic regression analysis was applied to identify the relevant predictors of functional outcome (favorable [mRS 1-2 points] versus unfavorable [mrS > = 3 points]).

RESULTS

Of the 142 consecutively screened patients, 96 were included in the analysis. Of these, 33/96 (34%) were identified as having SDB and were more likely to have unfavorable mRS scores as compared to those without SDB (odds ratio = 2.70, p-value = 0.032).

CONCLUSION

HRPO may be a low-cost and easily administered screening method to detect SDB among patients hospitalized for acute ischemic stroke. Patients with SDB (as defined by ODI) have a higher burden of neurological deficits as compared to those without SDB during hospitalization.

Pre-morbid sleep disturbance and its association with stroke severity: results from the international INTERSTROKE study

BACKGROUND AND PURPOSE

Whilst sleep disturbances are associated with stroke, their association with stroke severity is less certain. In the INTERSTROKE study, the association of pre-morbid sleep disturbance with stroke severity and functional outcome following stroke was evaluated.

METHODS

INTERSTROKE is an international case-control study of first acute stroke. This analysis included cases who completed a standardized questionnaire concerning nine symptoms of sleep disturbance (sleep onset latency, duration, quality, nocturnal awakening, napping duration, whether a nap was planned, snoring, snorting and breathing cessation) in the month prior to stroke (n = 2361). Two indices were derived representing sleep disturbance (range 0-9) and obstructive sleep apnoea (range 0-3) symptoms. Logistic regression was used to estimate the magnitude of association between symptoms and stroke severity defined by the modified Rankin Score.

RESULTS

The mean age of participants was 62.9 years, and 42% were female. On multivariable analysis, there was a graded association between increasing number of sleep disturbance symptoms and initially severe stroke (2-3, odds ratio [OR] 1.44, 95% confidence interval [CI] 1.07-1.94; 4-5, OR 1.66, 95% CI 1.23-2.25; >5, OR 2.58, 95% CI 1.83-3.66). Having >5 sleep disturbance symptoms was associated with significantly increased odds of functional deterioration at 1 month (OR 1.54, 95% CI 1.01-2.34). A higher obstructive sleep apnoea score was also associated with significantly increased odds of initially severe stroke (2-3, OR 1.48; 95% CI 1.20-1.83) but not functional deterioration at 1 month (OR 1.19, 95% CI 0.93-1.52).

CONCLUSIONS

Sleep disturbance symptoms were common and associated with an increased odds of severe stroke and functional deterioration. Interventions to modify sleep disturbance may help prevent disabling stroke/improve functional outcomes and should be the subject of future research.

Obstructive Sleep Apnea and Stroke: Determining the Mechanisms Behind their Association and Treatment Options

Sleep-disordered breathing (SDB) can be a sequela of stroke caused by vascular injury to vital respiratory centers, cerebral edema, and increased intracranial pressure of space-occupying lesions. Likewise, obstructive sleep apnea (OSA) contributes to increased stroke risk through local mechanisms such as impaired ischemic cerebrovascular response and systemic effects such as promoting atherosclerosis, hypercoagulability, cardiac arrhythmias, vascular-endothelial dysfunction, and metabolic syndrome. The impact of OSA on stroke outcomes has been established, yet it receives less attention in national guidelines on stroke management than hyperglycemia and blood pressure dysregulation. Furthermore, whether untreated OSA worsens stroke outcomes is not well-described in the literature. This scoping review provides an updated investigation of the correlation between OSA and stroke, including inter-relational pathophysiology. This review also highlights the importance of OSA treatment and its role in stroke outcomes. Knowledge of pathophysiology, the inter-relationship between these common disorders, and the impact of OSA therapy on outcomes affect the clinical management of patients with acute ischemic stroke. In addition, understanding the relationship between stroke outcomes and pre-existing OSA will allow clinicians to predict outcomes while treating acute stroke.

Heterogeneity of obstructive sleep apnea phenotypes after ischemic stroke: Outcome variation by cluster analysis

INTRODUCTION

Obstructive sleep apnea (OSA) is common but under-recognized after stroke. The aim of this study was to determine whether post-stroke phenotypic OSA subtypes are associated with stroke outcome in a population-based observational cohort.

METHODS

Ischemic stroke patients (n = 804) diagnosed with OSA (respiratory event index ≥10) soon after ischemic stroke were identified from the Brain Attack Surveillance in Corpus Christi (BASIC) project. Functional, cognitive, and quality of life outcomes were assessed at 90 days post-stroke and long-term stroke recurrence was ascertained. Latent profile analysis was performed based on demographic and clinical features, pre-stroke sleep characteristics, OSA severity, and vascular risk factors. Regression models were used to assess the association between phenotypic clusters and outcomes.

RESULTS

Four distinct phenotypic clusters provided the best fit. Cluster 1 was characterized by more severe stroke; cluster 2 by severe OSA and higher prevalence of medical comorbidities; cluster 3 by mild stroke and mild OSA; and cluster 4 by moderate OSA and mild stroke. Compared to cluster 3 and after adjustment for baseline stroke severity, cluster 1 and cluster 2 had worse 90-day functional outcome and cluster 1 also had worse quality of life. No difference in cognitive outcome or stroke recurrence rate was noted by cluster.

CONCLUSION

Post-stroke OSA is a heterogeneous disorder with different clinical phenotypes associated with stroke outcomes, including both daily function and quality of life. The unique presentations of OSA after stroke may have important implications for stroke prognosis and personalized treatment strategies.

Effect of ventilation modalities on the early prognosis of patients with poststroke sleep apnea

OBJECTIVE

Continuous positive airway pressure (CPAP) is the primary modality for treating sleep apnea after acute ischemic stroke (AIS). However, not all patients are well adherent to CPAP. Finding an alternative modality of ventilation to CPAP is essential.

METHODS

This prospective randomized clinical trial was conducted from 1 May 2022 to 8 January 2023 at the Department of Neurology, Wuhan Union Hospital. Participants diagnosed with sleep apnea after AIS were grouped according to block randomization principles into the usual care group (nasal cannula and facemask), nasal continuous positive airway pressure (nCPAP) group, and high-flow nasal cannula (HFNC) group. Rates of pulmonary infection and endotracheal intubation within 1 week of hospitalization and 28-day mortality (poststroke) were the primary outcomes (early prognosis).

RESULTS

In the trial, 178 patients (119 males [66.85%]; mean [SD] age, 61.04 [11.78] years) were eventually enrolled in the usual care group (n = 63), the nCPAP group (n = 55), and the HFNC group (n = 60). After ventilation, the nCPAP and HFNC groups were more effective than the usual care group in reducing the rate of pulmonary infection, endotracheal intubation, and improving neurological function and sleep apnea severity. However, there was no difference in 28-day mortality. Additionally, the improvement in prognosis was consistent between nCPAP and HFNC. In the comparison of comfort, the HFNC group was superior to nCPAP.

INTERPRETATION

nCPAP and HFNC reduced early pulmonary infection rates and endotracheal intubation rates. For patients with poor compliance with nCPAP, HFNC may be the best alternative.

Adherence to positive airway pressure therapy initiated in the early subacute phase of ischemic stroke: a PRESS study follow-up

BACKGROUND

Sleep-disordered breathing (SDB) is frequent in stroke patients and negatively affects stroke outcomes. Positive airway pressure (PAP) is the standard first-line treatment for patients with moderate-to-severe SDB. Despite a strong link between PAP adherence and therapeutic response, rates of post-stroke PAP adherence remain underexplored. Our study aimed to determine PAP adherence in patients undergoing comprehensive sleep apnea assessment and in-lab PAP titration in the early subacute phase of stroke.

METHODS

In-hospital screening pulse oximetry was performed in consecutive patients with imaging-confirmed acute ischemic stroke. Subjects with desaturation index ≥ 15.3/h were selected as PAP candidates, and polysomnography was recommended. In a sleep laboratory setting, subjects underwent a diagnostic night followed by a titration night, and PAP therapy was initiated in subjects with apnea-hypopnea index ≥ 15/h. Adherence to PAP therapy was assessed at a 6-month follow-up visit.

RESULTS

Of 225 consecutive patients with acute ischemic stroke, 116 were PAP candidates and 52 were able to undergo polysomnography. PAP therapy was initiated in 35 subjects. At a 6-month follow-up visit, out of 34 stroke survivors, PAP adherence (PAP use of > 4 h per night) was present in 47%. Except for the significantly lower minimal nocturnal O2 saturation determined from the polysomnography (74.6 ± 11.7% vs. 81.8 ± 5.2%, p = 0.025), no other significant difference in characteristics of the groups with PAP adherence and PAP non-adherence was found.

CONCLUSIONS

Less than half of the stroke subjects remained adherent to PAP therapy at 6 months post-PAP initiation. Special attention to support adaptation and adherence to PAP treatment is needed in this group of patients.

Effect of different ventilation modalities on the early prognosis of patients with sleep apnea after acute ischemic stroke---protocol for a prospective, open-label and randomised controlled trial

BACKGROUND

Sleep apnea is highly prevalent after acute ischemic stroke (AIS) and has increased stroke-related mortality and morbidity. The conventional sleep apnea treatment is continuous positive airway pressure (CPAP) ventilation. However, it is poorly tolerated by patients and is not used in all stroke patients. This protocol describes the impact of high-flow nasal cannula (HFNC) oxygen therapy compared to nasal continuous positive airway pressure (nCPAP) ventilation or usual care on the early prognosis of patients with sleep apnea after AIS.

METHODS

This randomised controlled study will be conducted in the intensive care unit of the Department of Neurology at the Wuhan Union Hospital. According to the study plan, 150 patients with sleep apnea after AIS will be recruited. All patients are randomly allocated in a 1:1:1 ratio to one of three groups: the nasal catheter group (standard oxygen group), the HFNC group, and the nCPAP group. Patients receive different types of ventilation after admission to the group, and their tolerance while using the different ventilation is recorded. Patients will be followed up by telephone three months after discharge, and stroke recovery is recorded. The primary outcomes were 28-day mortality, the incidence of pulmonary infection and endotracheal intubation.

DISCUSSION

This study analyses different ventilation modalities for early interventions in patients with sleep apnea after AIS. We will investigate whether nCPAP and HFNC reduce early mortality and endotracheal intubation rates and improve distant neurological recovery in patients.

TRIAL REGISTRATION

This trial was registered at ClinicalTrials.gov (NCT05323266; 25 March 2022).

Post-stroke sleep disturbance and recurrent cardiovascular and cerebrovascular events: A systematic review and meta-analysis

Despite improvements in survival rates, risk of recurrent events following stroke remains high. Identifying intervention targets to reduce secondary cardiovascular risk in stroke survivors is a priority. The relationship between sleep and stroke is complex: sleep disturbances are likely both a contributor to, and consequence of, stroke. The current aim was to examine the association between sleep disturbance and recurrent major acute coronary events or all-cause mortality in the post-stroke population. Thirty-two studies were identified, including 22 observational studies and 10 randomized clinical trials (RCTs). Identified studies included the following as predictors of post-stroke recurrent events: obstructive sleep apnea (OSA, n = 15 studies), treatment of OSA with positive airway pressure (PAP, n = 13 studies), sleep quality and/or insomnia (n = 3 studies), sleep duration (n = 1 study), polysomnographic sleep/sleep architecture metrics (n = 1 study), and restless legs syndrome (n = 1 study). A positive relationship of OSA and/or OSA severity with recurrent events/mortality was seen. Findings on PAP treatment for OSA were mixed. Positive findings indicating a benefit of PAP for post-stroke risk came largely from observational studies (pooled RR [95% CI] for association between PAP and recurrent cardiovascular event: 0.37 [0.17-0.79], I2 = 0%). Negative findings came largely from RCTs (RR [95% CI] for association between PAP and recurrent cardiovascular event + death: 0.70 [0.43-1.13], I2 = 30%). From the limited number of studies conducted to date, insomnia symptoms/poor sleep quality and long sleep duration were associated with increased risk. Sleep, a modifiable behavior, may be a secondary prevention target to reduce the risk of recurrent event and death following stroke. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42021266558.

Sleep Apnea Syndrome (SAS) Clinical Practice Guidelines 2020

The prevalence of sleep-disordered breathing (SDB) is reportedly very high. Among SDBs, the incidence of obstructive sleep apnea (OSA) is higher than previously believed, with patients having moderate-to-severe OSA accounting for approximately 20% of adult males and 10% of postmenopausal women not only in Western countries but also in Eastern countries, including Japan. Since 1998, when health insurance coverage became available, the number of patients using continuous positive airway pressure (CPAP) therapy for sleep apnea has increased sharply, with the number of patients about to exceed 500,000 in Japan. Although the "Guidelines for Diagnosis and Treatment of Sleep Apnea Syndrome (SAS) in Adults" was published in 2005, a new guideline was prepared to indicate the standard medical care based on the latest trends, as supervised by and in cooperation with the Japanese Respiratory Society and the "Survey and Research on Refractory Respiratory Diseases and Pulmonary Hypertension" Group, of Ministry of Health, Labor and Welfare and other related academic societies, including the Japanese Society of Sleep Research, in addition to referring to the previous guidelines. Since sleep apnea is an interdisciplinary field covering many areas, this guideline was prepared including 36 clinical questions (CQs). In the English version, therapies and managements for SAS, which were written from CQ16 to 36, were shown. The Japanese version was published in July 2020 and permitted as well as published as one of the Medical Information Network Distribution Service (Minds) clinical practice guidelines in Japan in July 2021.

Stroke and breathing

Stroke remains a leading cause of neurologic disability with wide ranging effects, including a variety of respiratory abnormalities. Stroke may influence the central control of the respiratory drive and breathing pattern, airway protection and maintenance, and the respiratory mechanics of inspiration and expiration. In the acute phase of stroke, the central control of breathing is affected by changes in consciousness, cerebral edema, and direct damage to brainstem respiratory centers, resulting in abnormalities in respiratory pattern and loss of airway protection. Common acute complications related to respiratory dysfunction include dysphagia, aspiration, and pneumonia. Respiratory control centers are located in the brainstem, and brainstem stroke causes specific patterns of respiratory dysfunction. Depending on the exact location and extent of stroke, respiratory failure may occur. While major respiratory abnormalities often improve over time, sleep-disordered breathing remains common in the subacute and chronic phases and worsens outcomes. Respiratory mechanics are impaired in hemiplegic or hemiparetic stroke, contributing to worse cardiopulmonary health in stroke survivors. Interventions to address the respiratory complications are under researched, and further investigation in this area is critical to improving outcomes among stroke survivors.

Sleep apnea and stroke

PURPOSE OF REVIEW

Stroke and sleep apnea are highly prevalent conditions with a physiologically plausible bidirectional relationship. This review addresses prestroke sleep apnea, wake-up stroke and sleep apnea, and poststroke sleep apnea, with an attempt to highlight research published in the last 18 months.

RECENT FINDINGS

Sleep apnea is highly prevalent poststroke. Poststroke sleep apnea is associated with worse poststroke functional and cognitive outcomes and a higher risk of recurrent stroke. Physiologic tests are needed to diagnose sleep apnea in poststroke patients as sleep apnea questionnaires do not perform well in this population. The role of CPAP in poststroke management is not yet well established.

SUMMARY

Sleep apnea is a well established independent risk factor for stroke that confers an approximately two-fold increased risk of incident stroke. Sleep apnea is highly prevalent poststroke and is associated with worse outcomes after stroke. Sleep apnea is an attractive target for research addressing secondary stroke prevention and recovery.

Effects of surgery for obstructive sleep apnea on cognitive function and driving performance

BACKGROUND

Obstructive sleep apnea (OSA) is associated with a significantly increased risk of motor vehicle accidents in addition to such cognitive impairments as attention and memory deficits. The aim of the study was to examine the effect of upper airway surgery for OSA on driving and cognitive function.

METHODS

Adult patients who underwent surgery for OSA at a tertiary medical center in 2016-2019 were prospectively recruited. Patients were assessed before and 3-6 months after surgery with a self-report and neurocognitive battery and a driving simulation platform.

RESULTS

The cohort included 32 patients of average age 46.9 ± 11.6 years. During the 3 years before treatment, 9 patients had been involved in road accidents and 18 were detained by police for traffic violations. After surgery, there was a significant decrease in the Epworth Sleepiness Scale (13.7 vs. 8.1, p 0.043) and a significant reduction in time to completion of the Color Trail Test (part 1: 21.4 vs 18.7 s, p = 0.049; part 2: 46.8 vs 40.5 s, p = 0.038). Improvements in divided attention and selective attention response times were noted on the advanced stages of the Useful Field of Vision Scale (p = 0.013, p = 0.054). Before surgery, patients showed a high tendency to drive over the speed limit and to cross the dividing line to the opposite lane on the simulation test. Nevertheless, all considered themselves good drivers. These tendencies decreased after treatment.

CONCLUSIONS

Surgery for OSA can significantly improve driving performance and cognitive function.

The Impact of Sleep Disorders on Functional Recovery and Participation Following Stroke: A Systematic Review and Meta-Analysis

Background

Adequate sleep is vital for health and quality of life. People with stroke and a concomitant sleep disorder may have poorer outcomes than those without a sleep disorder.

Objective

To systematically evaluate the published literature to determine the impact of sleep disorders on physical, functional recovery at the activity and participation level after stroke.

Methods

A systematic review was conducted using PubMed, CINAHL, Scopus, and PsycINFO. Studies were selected that reported outcomes on physical, functional recovery at the activity and participation levels in participants with stroke and a diagnosed sleep disorder. A meta-analysis was performed on included studies that reported Barthel Index (BI) and modified Rankin Scale (mRS) scores. Results: A total of 33 studies were included in the systematic review with 9 of them in the meta-analysis. The mean mRS score was 0.51 points higher in participants with stroke and sleep disorders versus participants with stroke without sleep disorder [95% CI: 0.23-0.78]. The mean BI score was 10.2 points lower in participants with stroke and sleep disorders versus participants with stroke without sleep disorder [95% CI: −17.9 to −2.6].

Conclusions

People with stroke and a sleep disorder have greater functional limitations and disability than those without a sleep disorder. Rehabilitation professionals should screen their patients with stroke for potential sleep disorders and further research is needed to develop sleep and rehabilitation interventions that can be delivered in combination. PROSPERO registration number: CRD42019125562.

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.

Sleep for Stroke Management and Recovery Trial (Sleep SMART): Rationale and methods

RATIONALE

Obstructive sleep apnea is common among patients with acute ischemic stroke and is associated with reduced functional recovery and an increased risk for recurrent vascular events.

AIMS AND/OR HYPOTHESIS

The Sleep for Stroke Management and Recovery Trial (Sleep SMART) aims to determine whether automatically adjusting continuous positive airway pressure (aCPAP) treatment for obstructive sleep apnea improves clinical outcomes after acute ischemic stroke or high-risk transient ischemic attack.

SAMPLE SIZE ESTIMATE

A total of 3062 randomized subjects for the prevention of recurrent serious vascular events, and among these, 1362 stroke survivors for the recovery outcome.

METHODS AND DESIGN

Sleep SMART is a phase III, multicenter, prospective randomized, open, blinded outcome event assessed controlled trial. Adults with recent acute ischemic stroke/transient ischemic attack and no contraindication to aCPAP are screened for obstructive sleep apnea with a portable sleep apnea test. Subjects with confirmed obstructive sleep apnea but without predominant central sleep apnea proceed to a run-in night of aCPAP. Subjects with use (≥4 h) of aCPAP and without development of significant central apneas are randomized to aCPAP plus usual care or care-as-usual for six months. Telemedicine is used to monitor and facilitate aCPAP adherence remotely.

STUDY OUTCOMES

Two separate primary outcomes: (1) the composite of recurrent acute ischemic stroke, acute coronary syndrome, and all-cause mortality (prevention) and (2) the modified Rankin scale scores (recovery) at six- and three-month post-randomization, respectively.

DISCUSSION

Sleep SMART represents the first large trial to test whether aCPAP for obstructive sleep apnea after stroke/transient ischemic attack reduces recurrent vascular events or death, and improves functional recovery.

Obstructive sleep apnea and cardiovascular disease, a story of confounders!

Obstructive sleep apnea (OSA) syndrome is increasingly common among middle aged and older adults and is frequently linked to most cardiovascular diseases (CVD). Sleep-disordered breathing and CVD share a number of common risk factors and comorbid conditions including obesity, male gender, advancing age, metabolic syndrome, and hypertension. OSA appears to be associated with worsened CVD outcomes, sleep-related symptoms, quality of life, and risk of motor vehicle accidents. Demonstrating a cause-and-effect relationship between CVD and OSA has been challenging due to shared comorbidities. Strong evidence demonstrating clinically significant benefit for OSA treatments on OSA-related CVD outcomes are limited. In this review, we evaluate potential pathophysiologic mechanisms that link OSA to CVD and focus on specific treatments for OSA, including positive airway pressure (PAP), dental devices, and surgeries with regard to OSA-related CVD outcomes.

Driving performance following a wrist fracture: A pilot study using a driving simulator

Introduction

Driving performance, as assessed using a driving simulator, after distal radius fracture has not been previously studied. Our aims were to undertake a pilot study to assess feasibility via: (i) acceptability of driving simulation for this assessment purpose, (ii) recruitment and retention, (iii) sample size calculation. Preliminary evaluations of differences in driving performance between individuals recovering from distal radius fracture and controls were conducted to confirm if the methodology provided meaningful results to aid in justification for future studies.

Methods

Driving performance of 22 current drivers (aged 21–81 years), recruited by convenience sampling, was assessed using a driving simulator. The fracture group included those recovering from distal radius fracture managed with open reduction and internal fixation using a volar plate. The control group were uninjured individuals. Assessment was performed approximately five weeks post-surgery and follow-up assessment two weeks later. Acceptability outcome measures included pain and simulator sickness scores, feasibility measures included retention rates and measures of driving performance included time spent speeding, time spent out of the lane, standard deviation of lateral position and hazard reactions.

Results

The assessment was completed by 91% of participants; two participants dropped out secondary to simulator sickness. Retention rates were 83%. Preliminary results suggest those with distal radius fracture spent more time out of the lane and less time speeding.

Conclusion

This method was sensitive, acceptable and feasible according to the parameters of this pilot study. The results from this small sample suggest that between-group differences in driving performance are measurable using driving simulation five weeks following distal radius fracture.

Do apneas and hypopneas best reflect risk for poor outcomes after stroke?

OBJECTIVE/BACKGROUND

Sleep apnea (SA) is associated with poor outcomes after stroke. The best sleep apnea-related measure to capture this relationship is currently unknown. This measure or its underlying pathophysiology could serve as a treatment target.

PATIENTS/METHODS

Within the population-based Brain Attack Surveillance in Corpus Christi (BASIC) project, the ApneaLink Plus was used to perform sleep apnea tests shortly after ischemic stroke (2010-2015). Functional and cognitive outcomes were measured via in-person interviews 90-days post-stroke. Recurrent stroke was assessed longitudinally through active and passive surveillance procedures. After standardization to allow direct comparisons, adjusted models were built for each ApneaLink Plus measure and each outcome, to assess the effect of 1 standard deviation difference in the measure.

RESULTS

Among 995 subjects, median age was 67 years (interquartile range: 59, 78) and 52% were women. The respiratory event index had the strongest relationship with functional outcome (mean difference = 0.094, 95% confidence interval (CI): 0.040, 0.147). Desaturations ≤85% were associated with worse functional outcome (mean difference = 0.016, 95% CI: 0.002, 0.030), but desaturations ≤ 90% were not. Obstructive apnea index (OAI) showed the strongest association with cognitive outcome (mean difference = -0.079, 95% CI: -0.162, 0.005), but was not significant. Oxygen desaturation index (ODI) showed the strongest association with recurrent ischemic stroke (hazard ratio = 1.338, 95% CI: 1.016, 1.759).

CONCLUSIONS

Measurements easily obtained from a commonly used home sleep apnea test predicted outcomes differentially. This suggests the possibility of different SA-associated targets (perhaps using strategies more tolerable than standard treatment) based on the outcome of interest.

The No-apnea score vs. the other five questionnaires in screening for obstructive sleep apnea-hypopnea syndrome in patients with cerebral infarction

Background

Given the growing number of patients suspected of having obstructive sleep apnea-hypopnea syndrome (OSAHS), screening methods have become increasingly important for sleep clinics. We analyzed the clinical value of the No-apnea score which is used to diagnose OSAHS in patients with cerebral infarction, and compared the accuracy of the No-apnea score with the accuracy of the NoSAS score, the STOP-Bang questionnaire (SBQ), the Epworth Sleepiness Scale (ESS), the STOP questionnaire (STOP) and the Berlin questionnaire (BQ).

Methods

Between January 2014 and December 2018, a total of 221 cerebral infarction patients, suspected of having OSAHS, underwent the polysomnography (PSG) for one night at the sleep medical center of Guangdong Medical University Affiliated Second Hospital. The PSG data were collected and analyzed with the NoSAS score, the SBQ, the ESS, the STOP, the BQ, and patients' demographic information. Based on the apnea-hypopnea index (AHI), the patients were classified into four groups: the normal group (<5 events/h), mild OSAHS group (5-15 events/h), moderate OSAHS group (15-30 events/h) and severe OSAHS group (≥30 events/h). The sensitivity, specificity, positive predictive value, negative predictive value and areas under the curve (AUC) of the Receiver Operating Curve (ROC) were calculated for the five questionnaires to compare their relative efficacies for diagnosing OSAHS.

Results

When using the standard of AHI ≥5 for diagnosing OSAHS, the NoSAS score had an AUC of 0.831; the SBQ had an AUC of 0.730; the BQ had an AUC of 0.698; and the STOP had an AUC of 0.735, so these techniques are relatively accurate in diagnosing OSAHS. On the other hand, the No-apnea score and the ESS score are relatively less accurate comparing to the rest: the No-apnea had an AUC of 0.626, and the ESS had an AUC of 0.650. Using the NoSAS score to predict AHI ≥5 events/h, AHI ≥15 events/h and AHI ≥30 events/h, the sensitivity and specificity were 0.867 and 0.731, 0.888 and 0.476, 0.889 and 0.369, respectively; Using the SBQ to predict AHI ≥5 events/h, AHI 15 events/h and AHI ≥30 events/h, the sensitivity and specificity were 0.903 and 0.268, 0.914 and 0.200, 0.903 and 0.268, respectively; Using the STOP to predict AHI ≥5 events/h, AHI ≥15 events/h and AHI ≥30 events/h, the values were 0.830 and 0.500, 0.871 and 0.390, 0.875 and 0.302, respectively; and using the BQ to predict AHI ≥5 events/h, AHI ≥15 events/h and AHI ≥30 events/h, the values were 0.758 and 0.482, 0.810 and 0.429, 0.819 and 0.362, respectively.

Conclusions

The study concludes that the NoSAS score and the SBQ had a better predictive value for cerebral infarction patients suspected with OSAHS disease. These questionnaires can also effectively help clinicians quickly address nocturnal hypoxia in patients with cerebral infarction to control subsequent complications in patients with cerebral infarction. More studies are needed to evaluate the efficacy of the NoSAS score in screening for OSAHS in patients with cerebral infarction.

Sleep-disordered breathing and poststroke outcomes

OBJECTIVE

To examine the association between sleep-disordered breathing and stroke outcomes, and determine the contribution of sleep-disordered breathing to outcome disparities in Mexican Americans.

METHODS

Ischemic stroke patients (n = 995), identified from the population-based Brain Attack Surveillance in Corpus Christi Project (2010-2015), were offered participation in a sleep-disordered breathing study including a home sleep apnea test (ApneaLink Plus). Sleep-disordered breathing (respiratory event index ≥10) was determined soon after stroke. Neurologic, functional, cognitive, and quality of life outcomes were assessed at 90 days poststroke. Regression models were used to assess associations between sleep-disordered breathing and outcomes, adjusted for sociodemographics, prestroke function and cognition, health-risk behaviors, stroke severity, and vascular risk factors.

RESULTS

Median age was 67 years (interquartile range [IQR] = 59-78); 62.1% were Mexican American. Median respiratory event index was 14 (IQR = 6-25); 62.8% had sleep-disordered breathing. Sleep-disordered breathing was associated with worse functional outcome (mean difference in activities of daily living/instrumental activities of daily living score = 0.15, 95% confidence interval [CI] = 0.01-0.28) and cognitive outcome (mean difference in modified Mini-Mental State Examination = -2.66, 95% CI = -4.85 to -0.47) but not neurologic or quality of life outcomes. Sleep-disordered breathing accounted for 9 to 10% of ethnic differences in functional and cognitive outcome and was associated with cognitive outcome more strongly for Mexican Americans (β = -3.97, 95% CI = -6.63 to -1.31) than non-Hispanic whites (β = -0.40, 95% CI = -4.18 to 3.39, p-interaction = 0.15).

INTERPRETATION

Sleep-disordered breathing is associated with worse functional and cognitive function at 90 days poststroke. These outcomes are reasonable endpoints for future trials of sleep-disordered breathing treatment in stroke. If effective, sleep-disordered breathing treatment may somewhat lessen ethnic stroke outcome disparities. ANN NEUROL 2019;86:241-250.

The pedunculopontine region and breathing in Parkinson's disease

Objective

Respiratory abnormalities such as upper airway obstruction are common in Parkinson's disease (PD) and are an important cause of mortality and morbidity. We tested the effect of pedunculopontine region (PPNr) stimulation on respiratory maneuvers in human participants with PD, and separately recorded PPNr neural activity reflected in the local field potential (LFP) during these maneuvers.

Methods

Nine patients with deep brain stimulation electrodes in PPNr, and seven in globus pallidus interna (GPi) were studied during trials of maximal inspiration followed by forced expiration with stimulation OFF and ON. Local field potentials (LFPs) were recorded in the unstimulated condition.

Results

PEFR increased from 6.41 ± 0.63 L/sec in the OFF stimulation state to 7.5 L ± 0.65 L/sec in the ON stimulation state (z = −2.666, df = 8, P = 0.024). Percentage improvement in PEFR was strongly correlated with proximity of the stimulated electrode contact to the mesencephalic locomotor region in the rostral PPN (r = 0.814, n = 9, P = 0.008). Mean PPNr LFP power increased within the alpha band (7–11 Hz) during forced respiratory maneuvers (1.63 ± 0.16 μV²/Hz) compared to resting breathing (0.77 ± 0.16 μV²/Hz; z = −2.197, df = 6, P = 0.028). No changes in alpha activity or spirometric indices were seen with GPi recording or stimulation. Percentage improvement in PEFR was strongly positively correlated with increase in alpha power (r = 0.653, n = 14 (7 PPNr patients recorded bilaterally), P = 0.0096).

Interpretation

PPNr stimulation in PD improves indices of upper airway function. Increased alpha‐band activity is seen within the PPNr during forced respiratory maneuvers. Our findings suggest a link between the PPNr and respiratory performance in PD.

Clinical phenotypes of obstructive sleep apnea after ischemic stroke: a cluster analysis

BACKGROUND

Obstructive sleep apnea (OSA) is highly prevalent in patients with ischemic stroke. Untreated OSA is associated with an increased risk of cardiovascular morbidity and OSA treatment may improve neurological recovery in stroke survivors, yet OSA in stroke patients remains poorly characterized. The goal of this study is to identify clinical phenotypes of ischemic stroke patients with OSA.

METHODS

Participants (n = 451) with ischemic strokes and OSA (respiratory-event-index, (REI) ≥ 10/hour based on home sleep apnea testing) were identified from the Brain Attack Surveillance in Corpus Christi (BASIC) project. Latent class analysis was performed based on the following variables: age, sex, race/ethnicity, REI, pre-stroke snoring, pre-stroke tiredness/fatigue, pre-stroke sleep duration, prior stroke history, NIHSS at presentation, body mass index (BMI), hypertension, diabetes, atrial fibrillation, coronary artery disease, and chronic heart failure.

RESULTS

A model with three phenotype clusters provided the best fit. Cluster 1 (n = 55, 12%) was defined by higher NIHSS scores. Participants in cluster 2 (n = 253, 56%) were younger and had relatively low NIHSS scores. Cluster 3 (n = 143, 32%) included participants with severe OSA and higher prevalence of medical comorbidities.

CONCLUSION

Ischemic stroke survivors with OSA can be categorized into three clinical phenotype clusters characterized by differences in stroke severity, OSA severity, age and medical comorbidities. This highlights the heterogeneity of post-stroke OSA. Awareness of the different faces of OSA in patients with ischemic stroke may help clinicians identify OSA in their patients, and inform research concerning the pathophysiology, treatment and prognostic impact of post-stroke OSA.

Microvascular cerebral blood flow fluctuations in association with apneas and hypopneas in acute ischemic stroke

In a pilot study on acute ischemic stroke (AIS) patients, unexpected periodic fluctuations in microvascular cerebral blood flow (CBF) had been observed. Motivated by the relative lack of information about the impact of the emergence of breathing disorders in association with stroke on cerebral hemodynamics, we hypothesized that these fluctuations are due to apneic and hypopneic events. A total of 28 patients were screened within the first week after stroke with a pulse oximeter. Five (18%) showed fluctuations of arterial blood oxygen saturation ( ≥ 3 % ) and were included in the study. Near-infrared diffuse correlation spectroscopy (DCS) was utilized bilaterally to measure the frontal lobe CBF alongside respiratory polygraphy. Biphasic CBF fluctuations were observed with a bilateral increase of 27.1 % ± 17.7 % and 29.0 % ± 17.4 % for the ipsilesional and contralesional hemispheres, respectively, and a decrease of - 19.3 % ± 9.1 % and - 21.0 % ± 8.9 % for the ipsilesional and contralesional hemispheres, respectively. The polygraph revealed that, in general, the fluctuations were associated with apneic and hypopneic events. This study motivates us to investigate whether the impact of altered respiratory patterns on cerebral hemodynamics can be detrimental in AIS patients.

Sleep-Disordered Breathing Is Associated With Recurrent Ischemic Stroke

Background and Purpose- Limited data are available about the relationship between sleep-disordered breathing (SDB) and recurrent stroke and mortality, especially from population-based studies, large samples, or ethnically diverse populations. Methods- In the BASIC project (Brain Attack Surveillance in Corpus Christ), we identified patients with ischemic stroke (2010-2015). Subjects were offered screening for SDB with the ApneaLink Plus device, from which a respiratory event index (REI) score ≥10 defined SDB. Demographics and baseline characteristics were determined from chart review and interview. Recurrent ischemic stroke was identified through active and passive surveillance. Cause-specific proportional hazards models were used to assess the association between REI (modeled linearly) and ischemic stroke recurrence (as the event of interest), and all-cause poststroke mortality, adjusted for multiple potential confounders. Results- Among 842 subjects, the median age was 65 (interquartile range, 57-76), 47% were female, and 58% were Mexican American. The median REI score was 14 (interquartile range, 6-26); 63% had SDB. SDB was associated with male sex, Mexican American ethnicity, being insured, nonsmoking status, diabetes mellitus, hypertension, lower educational attainment, and higher body mass index. Among Mexican American and non-Hispanic whites, 85 (11%) ischemic recurrent strokes and 104 (13%) deaths occurred, with a median follow-up time of 591 days. In fully adjusted models, REI was associated with recurrent ischemic stroke (hazard ratio, 1.02 [hazard ratio for one-unit higher REI score, 95% CI, 1.01-1.03]), but not with mortality alone (hazard ratio, 1.00 [95% CI, 0.99-1.02]). Conclusions- Results from this large population-based study show that SDB is associated with recurrent ischemic stroke, but not mortality. SDB may therefore represent an important modifiable risk factor for poor stroke outcomes.

The Evolution of Sleep Apnea Six Months After Acute Ischemic Stroke and Thrombolysis

STUDY OBJECTIVES

Our goal was to investigate the evolution of prevalence, severity, and type of sleep apnea among patients who had an ischemic stroke, with or without treatment with thrombolysis after 6 months.

METHODS

We prospectively studied 204 patients who had an ischemic stroke (110 in the thrombolysis and 94 in the non-thrombolysis group). After follow-up, 177 patients were eligible for a final analysis (98 in the thrombolysis group and 79 in the non-thrombolysis group). An unattended sleep study with a three-channel portable device was performed both on admission and after the 6-month follow-up.

RESULTS

The patients receiving thrombolysis were younger than those in the non-thrombolysis group (mean 65.5 versus 69.6 years P = .039). Sleep apnea, defined as a respiratory event index (REI) ≥ 5 events/h, was diagnosed in 92.7% patients, 93.9% versus 91.1% (P = .488) in the thrombolysis and non-thrombolysis groups, respectively. The prevalence remained unchanged during follow-up. Mild sleep apnea progressed to moderate or severe sleep apnea in 69.2% of the patients. Globally, mean central apneas per hour increased by 2.2% (P = .002), whereas obstructive apneas declined by 1.7% (P = .014). The mean change of oxygen desaturation index was -6.1% (P < .001) in the thrombolysis group, -1.8% (P = .327) in the non-thrombolysis group, and 4.2% (P = .001) in the whole group. In the non-thrombolysis group, the risk for new sleep apnea incidence increased by 6.1-fold (P = .024) at follow-up when compared to the thrombolysis group.

CONCLUSIONS

Sleep apnea prevalence remained high in patients who had an ischemic stroke at 6 months post-stroke. The risk for developing sleep apnea after stroke was significantly lower among patients undergoing thrombolysis.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Title: Ischaemic Stroke and Sleep Apnea in Northern Part of Finland; Identifier: NCT01861275; URL: https://clinicaltrials.gov/ct2/show/NCT01861275.

Sleep apnea screening is uncommon after stroke

OBJECTIVE/BACKGROUND

To assess (1) pre and post-stroke screening for sleep apnea (SA) within a population-based study without an academic medical center, and (2) ethnic differences in post-stroke sleep apnea screening among Mexican Americans (MAs) and non-Hispanic whites (NHWs).

PATIENTS/METHODS

MAs and NHWs with stroke in the Brain Attack Surveillance in Corpus Christi project (2011-2015) were interviewed shortly after stroke about the pre-stroke period, and again at approximately 90 days after stroke in reference to the post-stroke period. Questions included whether any clinical provider directly asked about snoring or daytime sleepiness or had offered polysomnography. Logistic regression tested the association between these outcomes and ethnicity both unadjusted and adjusted for potential confounders.

RESULTS

Among 981 participants, 63% were MA. MAs in comparison to NHWs were younger, had a higher prevalence of hypertension, diabetes, and never smoking, a higher body mass index, and a lower prevalence of atrial fibrillation. Only 17% reported having been offered SA diagnostic testing pre-stroke, without a difference by ethnicity. In the post-stroke period, only 50 (5%) participants reported being directly queried about snoring; 86 (9%) reported being directly queried about sleepiness; and 55 (6%) reported having been offered polysomnography. No ethnic differences were found for these three outcomes, in unadjusted or adjusted analyses.

CONCLUSIONS

Screening for classic symptoms of SA, and formal testing for SA, are rare within the first 90 days after stroke, for both MAs and NHWs. Provider education is needed to raise awareness that SA affects most patients after stroke and is associated with poor outcomes.

Post-Stroke Sleep-Disordered Breathing-Pathophysiology and Therapy Options

Sleep-disordered breathing (SDB), encompassing both obstructive and central sleep apnea, is prevalent in at least 50% of stroke patients. Small studies have shown vast improvements in post-stroke functional recovery outcomes after the treatment of SDB by continuous positive airway pressure. However, compliance to this therapy is very poor in this complex patient group. There are alternative therapy options for SDB that may be more amenable for use in at least some post-stroke patients, including mandibular advancement, supine avoidance, and oxygen therapy. There are few studies, however, that demonstrate efficacy and compliance with these alternative therapies currently. Furthermore, novel SDB-phenotyping approaches may help to provide important clinical information to direct therapy selection in individual patients. Prior to realizing individualized therapy, we need a better understanding of the pathophysiology of SDB in post-stroke patients, including the role of inherent phenotypic traits, as well as the contribution of stroke size and location. This review summarizes the available literature on SDB pathophysiology and treatment in post-stroke patients, identifies gaps in the literature, and sets out areas for further research.

Sex differences in sleep-disordered breathing after stroke: results from the BASIC project

OBJECTIVE/BACKGROUND

Sleep-disordered breathing (SDB), an independent risk factor for stroke, is associated with worse post-stroke outcomes. Differences in the relationship between SDB and stroke may exist for women versus men. In this population-based study, we compared the prevalence of both pre- and post-stroke SDB by sex. We also explored whether menopausal status is related to post-stroke SDB.

PATIENTS/METHODS

We performed a cross-sectional study of subjects enrolled in the Brain Attack Surveillance in Corpus Christi (BASIC) project. Each subject (n = 1815) underwent a baseline interview including the Berlin Questionnaire to assess pre-stroke SDB risk and, if relevant, questions regarding menopausal status. Subjects were offered overnight SDB screening with a validated portable respiratory device (n = 832 with complete data). Log Poisson and linear regression models were used to assess the differences in SDB between men and women with adjustment for demographics, stroke risk factors, stroke severity, and other potential confounders.

RESULTS

Women were less likely than men to be at high risk for pre-stroke SDB (56.6% versus 61.9%) (prevalence ratio [PR] 0.87 for women; 95% confidence interval [CI], 0.81-0.95). A lower proportion of women than men (50.8% versus 70.2%) had post-stroke SDB by respiratory monitoring (PR 0.71; 95% CI, 0.63-0.80). SDB severity was higher for men than for women (mean difference in respiratory event index [REI] 6.5; 95% CI, 4.3-8.7). No significant association existed between post-stroke SDB and either menopausal status or age at menopause.

CONCLUSIONS

After acute ischemic stroke, SDB was more prevalent and more severe in men than in women.

Study of association of severity of sleep disordered breathing and functional outcome in stroke patients

OBJECTIVE

Sleep disordered breathing (SDB) is a prevalent yet underrecognized condition that may have major adverse consequences for those affected by it. We performed a prospective observational study to seek a correlation of severity of SDB with the severity of stroke and its functional outcome.

METHODS

Patients with history of recent-onset stroke were recruited and underwent overnight polysomnography (PSG) after the acute phase of the stroke was over; for defining hypopneas, 3% and 4% desaturation limits were used, and the apnea-hypopnea index was respectively calculated as AHI_3% and AHI_4%. Stroke severity was graded using the Scandinavian Stroke Scale. Functional disability and neurological impairment was evaluated six weeks after the PSG using the Barthel Index (<80 = functional dependence; ≥80 = functional independence) and modified Rankins Scale (>2 = poor outcome; ≤2 = good outcome).

RESULTS

A total of 50 patients were enrolled, 30 (60%) with ischemic stroke and 20 (40%) with hemorrhagic strokes. Of the patients, 39 (78%) had an AHI_4% of >5/h, 23 (46%) had an AHI_4% of >15/h, and 9 (18%) had an AHI_4% of >30/h. Multivariate analysis showed that body mass index (odds ratio [OR] = 1.26; 95% confidence interval [CI] = 1.04-1.54, p = 0.019) and Scandinavian Stroke Scale score (stroke severity) (OR = 0.86; 95% CI = 0.76-0.96, p = 0.009) were significant risk factors for predicting SDB (AHI_4% > 15) in patients of stroke. When we looked for factors predicting outcomes, only AHI_4% (OR = 1.20; 95% CI 1.01-1.43, p value 0.041) was predictive of the functional dependence (based on Barthel Index) of the patient and AHI_4% (OR = 1.14; 95% CI 1.03-1.25, p = 0.008) and body mass index (OR = 0.75; 95% CI 0.59-0.96, p = 0.024) were found to be predictive of poor outcome (based on modified Rankins Scale). We obtained similar results, regardless of the hypopnea definition used.

CONCLUSION

In conclusion, given the high frequency of SDB in stroke patients and its correlation with poor outcome, screening for obstructive sleep apnea in all stroke and transient ischemic attack patients may be warranted.

Rehabilitation of Cardiovascular Disorders and Sleep Apnea

Obstructive sleep apnea (OSA) is present in more than 50% of patients referred to cardiac rehabilitation units. However, it has been under-recognized in patients after stroke and heart failure. Those with concurrent OSA have a worse clinical course. Early treatment of coexisting OSA with continuous positive airway pressure (CPAP) results in improved rehabilitation outcomes and quality of life. Possible mechanisms by which CPAP may improve recovery include decreased blood pressure fluctuations associated with apneas, and improved left ventricular function, cerebral blood flow, and oxygenation. Early screening and treatment of OSA should be integral components of patients entering cardiac rehabilitation units.

Prevalence and Predictors of Sleep Apnea Risk among Ghanaian Stroke Survivors

BACKGROUND AND PURPOSE

Sleep apnea (SA) has emerged as a potent risk factor for stroke recurrence and mortality. The burden of SA among stroke survivors in sub-Saharan Africa where stroke incidence and mortality are escalating is unknown. We sought to assess the prevalence of SA risk and its clinical correlates and predictors among Ghanaian stroke survivors.

METHODS

This cross-sectional study involved 200 consecutive stroke survivors attending a neurology clinic in a tertiary medical center in Kumasi, Ghana. The validated Berlin, STOP-BANG, and Epworth Sleepiness Scale questionnaires were administered to all eligible subjects to assess SA risk and daytime somnolence, and their demographic and clinical information, health-related quality of life, and symptoms of depression were collected using the questionnaires.

RESULTS

The median (interquartile range) age of stroke survivors was 62 (52-72) years and 52.5% were male. Ninety-nine (49.5%) subjects were identified as high risk for SA using the Berlin questionnaire, whereas 26 (13%), 137 (68.5%), and 37 (18.5%) subjects were classified as low, intermediate, and high risk for SA, respectively, using the STOP-BANG questionnaire. Patients at high risk of SA were significantly older, used excess alcohol, and were less able to perform activities of daily living, although their mean National Institutes of Health Stroke Scale scores were significantly lower than those with low risk for SA. None of the stroke survivors had ever been screened for SA.

CONCLUSIONS

One out of every 2 stroke survivors attending a neurology clinic in Ghana is at high risk for undiagnosed SA. Greater regional awareness about SA presence and outcomes among patients and providers is warranted.

Sleep apnoea and stroke

Sleep disorders have been known to physicians for a long time. In his famous aphorisms, Hippocrates said “Sleep or watchfulness exceeding that which is customary, augurs unfavorably”. Modern medicine has been able to disentangle some of the phenomena that disturb sleep. Among the most notable offenders is sleep apnoea that has gained prominence in the past few decades. It is being proposed as one of the potentially modifiable risk factors for vascular diseases including stroke. The pathological mechanisms linking sleep apnoea to vascular risk factors include hypoxia, cardiac arrhythmias, dysautonomia, impaired glucose tolerance, hypertension, dyslipidaemia and inflammation. In this article, we review literature linking sleep apnoea and stroke, including sleep apnoea as a risk factor for primary prevention with the potential to improve outcome after acute stroke and as a secondary risk factor, amenable to modification and hence vascular risk reduction.

Expiratory Positive Airway Pressure for Sleep Apnea after Stroke: A Randomized, Crossover Trial

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is common after stroke and predicts poor outcomes. Continuous positive airway pressure (CPAP) treats OSA but is generally poorly tolerated by stroke patients. We assessed whether nasal expiratory positive airway pressure (EPAP), an alternative to CPAP, may be an effective option after acute stroke.

METHODS

We conducted a randomized, controlled, two-period crossover study in which each acute ischemic stroke patient received 1 night of EPAP and 1 night without EPAP while OSA was monitored with a validated device, the Watch-PAT 200. Linear repeated- measures analyses were conducted. Sample size calculations indicated that 18 subjects would be required to detect a 10-point or larger average reduction in the apnea-hypopnea index (AHI, the primary outcome), with use of EPAP, with power ≥ 80% and α = 0.05.

RESULTS

Among the 19 subjects who completed the protocol, nasal EPAP treatment was associated with a nonsignificant absolute difference in AHI of -5.73 events/h in the primary analysis (p = 0.183, 95% confidence interval -14.4, 2.97) and a nonsignificant absolute difference in AHI of -5.43 events/h in the subgroup of patients who used nasal EPAP for ≥ 3 h (p = 0.314, 95% confidence interval -16.6, 5.76).

CONCLUSIONS

This study suggests that EPAP is not an effective alternative to CPAP in acute stroke patients with OSA. Further work is needed to identify other more effective alternatives.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, ID: NCT01703663.

Effects of Continuous Positive Airway Pressure on Cognitive and Functional Outcome of Stroke Patients with Obstructive Sleep Apnea: A Randomized Controlled Trial

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) in stroke patients is associated with worse functional and cognitive status during inpatient rehabilitation. We hypothesized that a four-week period of continuous positive airway pressure (CPAP) treatment would improve cognitive and functional outcomes.

METHODS

We performed a randomized controlled trial in stroke patients admitted to a neurorehabilitation unit. Patients were assigned to rehabilitation treatment as usual (control group) or to CPAP treatment (CPAP group). Primary outcomes were cognitive status measured by neuropsychological examination, and functional status measured by two neurological scales and a measure of activities of daily living (ADL). Secondary measures included sleepiness, sleep quality, fatigue, and mood. Tests were performed at baseline and after the four-week intervention period.

RESULTS

We randomly assigned 20 patients to the CPAP group and 16 patients to the control group. The average CPAP compliance was 2.5 hours per night. Patients in the CPAP group showed significantly greater improvement in the cognitive domains of attention and executive functioning than the control group. CPAP compliance was associated with greater improvement in cognitive functioning. CPAP did not result in measurable improvement on measures of neurological status or ADL, or on any of the secondary measures.

CONCLUSIONS

CPAP treatment improves cognitive functioning of stroke patients with OSA.

COMMENTARY

A commentary on this article appears in this issue on page 467.

High prevalence of poststroke sleep-disordered breathing in Mexican Americans

OBJECTIVE

The purpose of this study is to compare sleep-disordered breathing (SDB) prevalence and severity after stroke between Mexican Americans (MAs) and non-Hispanic whites (NHWs).

PATIENTS/METHODS

Ischemic stroke (IS) patients within ∼30 days of onset were identified from the population-based BASIC Project (2010-2014) and offered screening with an overnight cardiopulmonary monitoring device, ApneaLink Plus™. The number of apneas and hypopneas per hour, as reflected by the apnea/hypopnea index (AHI), was used to measure SDB severity; SDB was defined as AHI ≥10. Ethnicity, demographics, and risk factors were collected from interviews and medical records. Log and negative-binomial regression models were used to determine prevalence ratios (PRs) and apnea/hypopnea event rate ratios (RRs) comparing MAs with NHWs after adjustment for demographics, risk factors, and stroke severity.

RESULTS

A total of 549 IS cases had AHI data. The median age was 65 years (interquartile range (IQR): 57-76), 55% were men, and 65% were MA. The MAs had a higher prevalence of SDB (68.5%) than NHWs (49.5%) in unadjusted (PR = 1.38; 95% confidence interval (CI): 1.14-1.67) and adjusted analyses (PR = 1.21; 95% CI: 1.01-1.46). The median AHI was 16 (IQR: 7-31) in MAs and nine (IQR: 5-24) in NHWs. The severity of SDB (rate of apneas/hypopneas) was higher in MAs than NHWs in unadjusted (RR = 1.31; 95% CI: 1.09-1.58) but not adjusted analysis (RR = 1.14; 95% CI: 0.95-1.38). There was no ethnic difference in severity among subjects with SDB.

CONCLUSION

More than two-thirds of MA stroke patients had SDB, which was almost 40% more common among MAs than NHWs. Physicians treating MA patients after stroke should have a high index of suspicion for SDB, a treatable condition that could otherwise have adverse impact.

Obstructive Sleep Apnea is Related to Impaired Cognitive and Functional Status after Stroke

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is a common sleep disorder in stroke patients and is associated with prolonged hospitalization, decreased functional outcome, and recurrent stroke. Research on the effect of OSA on cognitive functioning following stroke is scarce. The primary objective of this study was to compare stroke patients with and without OSA on cognitive and functional status upon admission to inpatient rehabilitation.

DESIGN

Case-control study.

SETTING AND PATIENTS

147 stroke patients admitted to a neurorehabilitation unit.

INTERVENTIONS

N/A.

MEASUREMENTS

All patients underwent sleep examination for diagnosis of OSA. We assessed cognitive status by neuropsychological examination and functional status by two neurological scales and a measure of functional independence.

RESULTS

We included 80 stroke patients with OSA and 67 stroke patients without OSA. OSA patients were older and had a higher body mass index than patients without OSA. OSA patients performed worse on tests of attention, executive functioning, visuoperception, psychomotor ability, and intelligence than those without OSA. No differences were found for vigilance, memory, and language. OSA patients had a worse neurological status, lower functional independence scores, and a longer period of hospitalization in the neurorehabilitation unit than the patients without OSA. OSA status was not associated with stroke type or classification.

CONCLUSIONS

Obstructive sleep apnea (OSA) is associated with a lower cognitive and functional status in patients admitted for stroke rehabilitation. This underlines the importance of OSA as a probable prognostic factor, and calls for well-designed randomized controlled trials to study its treatability.

A pilot study: portable out-of-center sleep testing as an early sleep apnea screening tool in acute ischemic stroke

INTRODUCTION

Prompt diagnosis of obstructive sleep apnea (OSA) after acute ischemic stroke (AIS) is critical for optimal clinical outcomes, but in-laboratory conventional polysomnograms (PSG) are not routinely practical. Though portable out-of-center type III cardiopulmonary sleep studies (out-of-center cardiopulmonary sleep testing [OCST]) are widely available, these studies have not been validated in patients who have recently suffered from AIS. We hypothesized that OCST in patients with AIS would yield similar results when compared to conventional PSG.

METHODS

Patients with AIS had simultaneous type III OCST and PSG studies performed within 72 hours from symptom onset. The accuracy of OCST was compared to PSG using: chi-square tests, receiver operatory characteristic curves, Bland-Altman plot, paired Student's t-test/Wilcoxon signed-rank test, and calculation of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).

RESULTS

Twenty-one out of 23 subjects with AIS (age 61±9.4 years; 52% male; 58% African-American) successfully completed both studies (9% technical failure). Nearly all (95%) had Mallampati IV posterior oropharynx; the mean neck circumference was 16.8±1.6 in. and the mean body mass index (BMI) was 30±7 kg/m(2). The apnea hypopnea index (AHI) provided by OCST was similar to that provided by PSG (19.8±18.0 vs 22.0±22.7, respectively; P=0.49). On identifying subjects by OCST with an AHI ≥5 on PSG, OCST had the following parameters: sensitivity 100%, specificity 85.7%, PPV 93%, and NPV 100%. On identifying subjects with an AHI ≥15 on PSG, OCST parameters were as follows: sensitivity 100%, specificity 83.3%, PPV 81.8%, and NPV 100%. Bland-Altman plotting showed an overall diagnostic agreement between OCST and PSG modalities for an AHI cutoff >5, despite fine-grained differences in estimated AHIs.

CONCLUSION

Compared with PSG, OCST provides similar diagnostic information when run simultaneously in AIS patients. OCST is a reliable screening tool for early diagnosis of OSA in AIS patients.

Ischemic stroke subtype and presence of sleep-disordered breathing: the BASIC sleep apnea study

BACKGROUND

Little is known about the prevalence of sleep-disordered breathing (SDB) across ischemic stroke subtypes. Given the important implications for SDB screening, we tested the association between SDB and ischemic stroke subtype in a population-based study.

METHODS

Within the Brain Attack Surveillance in Corpus Christi Project, ischemic stroke patients were offered SDB screening with the ApneaLink Plus (n = 355). A neurologist assigned Trial of the ORG 10172 in Acute Stroke Treatment subtype (with an additional category for nonlacunar infarctions of unknown etiology) using hospital records. Unadjusted and adjusted (demographics, body mass index, National Institutes of Health Stroke Scale, diabetes, history of stroke/transient ischemic attack) logistic and linear regression models were used to test the association between subtype and SDB or apnea-hypopnea index (AHI).

RESULTS

Median age was 65%, and 55% were men; 59% were Mexican American. Median time from stroke onset to SDB screen was 13 days (interquartile range [IQR] 6, 21). Overall, 215 (61%) had SDB (AHI ≥ 10). Median AHI was 13 (IQR 6, 27). Prevalence of SDB by subtype was cardioembolism, 66%; large-artery atherosclerosis, 57%; small-vessel occlusion, 68%; other determined, 50%; undetermined etiology, 58%; and nonlacunar stroke of unknown etiology, 63%. Ischemic stroke subtype was not associated with SDB in unadjusted (P = .72) or adjusted models (P = .91) models. Ischemic stroke subtype was not associated with AHI in unadjusted (P = .41) or adjusted models (P = .62).

CONCLUSIONS

In this population-based stroke surveillance study, ischemic stroke subtype was not associated with the presence or severity of SDB. Sleep-disordered breathing is likely to be present after ischemic stroke, and the subtype should not influence decisions about SDB screening.