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

Strengthening oropharyngeal muscles as an approach to treat post-stroke obstructive sleep apnea: A feasibility randomised controlled trial

This study aimed to determine the feasibility of a randomised controlled trial (RCT) evaluating oropharyngeal exercise (OPE) intervention as an alternative therapy for obstructive sleep apnea (OSA) in patients with stroke or transient ischaemic attack (TIA). Despite the high prevalence of OSA in this population, the standard therapy, continuous positive airway pressure (CPAP), is often poorly tolerated. Thirty stroke/TIA patients with OSA unable to tolerate CPAP were randomly assigned to an oropharyngeal exercise or sham exercise protocol. They performed exercises for 6 weeks, 5 days per week, 30 minutes twice per day. Feasibility was ascertained by the proportion of enrolled patients who completed more than 80% of the OPE regimen. Isometric tongue pressures, apnea-hypopnea index (AHI), oxygen desaturation index (ODI), daytime sleepiness, and quality of life (QOL) outcomes were collected at baseline, post-training (6-week follow-up), and retention (10-week follow-up) to document preliminary efficacy. Adherence to study exercises was excellent, with 83% of participants completing more than 80% of the exercises. The isometric tongue pressures were observed to improve in the oropharyngeal exercise group (compared with the sham group), along with a decrease in OSA severity (measured by the AHI and ODI), reduced daytime sleepiness, and enhanced quality of life outcomes following the exercise programme. Only the effects on posterior isometric tongue pressure and daytime sleepiness remained significantly different between groups at the retention session. In conclusion, an RCT evaluating the efficacy of oropharyngeal exercises on post-stroke/TIA OSA is feasible and our preliminary results suggest a clinically meaningful effect.

Prevalence and Detection of Obstructive Sleep Apnea Early after Stroke

Background

Obstructive sleep apnea (OSA) negatively impacts post-stroke recovery. This study's purpose: examine the prevalence of undiagnosed OSA and describe a simple tool to identify those at-risk for OSA in the early phase of stroke recovery.

Methods

This was a cross-sectional descriptive study of people ∼15 days post-stroke. Adults with stroke diagnosis admitted to inpatient rehabilitation over a 3-year period were included if they were alert/arousable, able to consent/assent to participation, and excluded if they had a pre-existing OSA diagnosis, other neurologic health conditions, recent craniectomy, global aphasia, inability to ambulate 150 feet independently pre-stroke, pregnant, or inability to understand English. OSA was deemed present if oxygen desaturation index (ODI) of >=15 resulted from overnight oximetry measures. Prevalence of OSA was determined accordingly. Four participant characteristics comprised the "BASH" tool (body mass index >=35, age>=50, sex=male, hypertension=yes). A receiver operator characteristics (ROC) curve analysis was performed with BASH as test variable and OSA presence as state variable.

Results

Participants (n=123) were 50.4% male, averaged 64.12 years old (sd 14.08), and self-identified race as 75.6% White, 20.3% Black/African American, 2.4%>1 race, and 1.6% other; 22% had OSA. ROC analysis indicated BASH score >=3 predicts presence of OSA (sensitivity=0.778, specificity=0.656, area under the curve =0.746, p<0.001).

Conclusions

Prevalence of undiagnosed OSA in the early stroke recovery phase is high. With detection of OSA post-stroke, it may be possible to offset untreated OSA's deleterious impact on post-stroke recovery of function. The BASH tool is an effective OSA screener for this application.

Sleep Apnea and Stroke: A Narrative Review

TOPIC IMPORTANCE

Stroke is the second-leading cause of death worldwide. OSA is an independent risk factor for stroke and is associated with multiple vascular risk factors. Poststroke OSA is prevalent and closely linked with various stroke subtypes, including cardioembolic stroke and cerebral small vessel disease. Observational studies have shown that untreated poststroke OSA is associated with an increased risk of recurrent stroke, mortality, poorer functional recovery, and longer hospitalizations.

REVIEW FINDINGS

Poststroke OSA tends to be underdiagnosed and undertreated, possibly because stroke patients with OSA present atypically compared with the general population with OSA. Objective testing, such as the use of ambulatory sleep testing or in-laboratory polysomnography, is recommended for diagnosing OSA. The gold standard for treating OSA is CPAP therapy. Randomized controlled trials (RCTs) have shown that treatment of poststroke OSA using CPAP improves nonvascular outcomes such as cognition and neurologic recovery. However, findings from RCTs that have evaluated the effect of CPAP on recurrent stroke risk and mortality have been largely negative.

SUMMARY

There is a need for high-quality RCTs in poststroke OSA that may provide evidence to support the utility of CPAP (and/or other treatment modalities) in reducing recurrent vascular events and mortality. This goal may be achieved by examining treatment strategies that have yet to be trialed in poststroke OSA, tailoring interventions according to poststroke OSA endotypes and phenotypes, selecting high-risk populations, and using metrics that reflect the physiological abnormalities that underlie the harmful effects of OSA on cardiovascular outcomes.

Up-to-date advance in the relationship between OSA and stroke: a narrative review

PURPOSE

Obstructive sleep apnea (OSA) and stroke affect each other. In this review, we summarized the effect of OSA on the onset and recurrence of stroke, the prognosis, and the treatment of poststroke patients with OSA.

METHODS

Pubmed/MEDLINE were searched through May 2023 to explore the relationship between OSA and stroke. The relevant papers included OSA and stroke, OSA and recurrent stroke, and the prognosis and treatment of poststroke patients with OSA.

RESULTS

The results showed that OSA can promote the onset and recurrence of stroke and that OSA may adversely affect the prognosis of poststroke patients. The application of continuous positive airway pressure (CPAP) and other treatments may benefit poststroke patients with OSA, though the long term effects of treatment are not well documented.

CONCLUSION

Both the onset and recurrence of stroke closely correlated with OSA, but the specific mechanisms remain unclear. Further studies should be carried out to explore effective treatments in patients with stroke and OSA.

Impact of Sleep Disorders and Disturbed Sleep on Brain Health: A Scientific Statement From the American Heart Association

Accumulating evidence supports a link between sleep disorders, disturbed sleep, and adverse brain health, ranging from stroke to subclinical cerebrovascular disease to cognitive outcomes, including the development of Alzheimer disease and Alzheimer disease-related dementias. Sleep disorders such as sleep-disordered breathing (eg, obstructive sleep apnea), and other sleep disturbances, as well, some of which are also considered sleep disorders (eg, insomnia, sleep fragmentation, circadian rhythm disorders, and extreme sleep duration), have been associated with adverse brain health. Understanding the causal role of sleep disorders and disturbances in the development of adverse brain health is complicated by the common development of sleep disorders among individuals with neurodegenerative disease. In addition to the role of sleep disorders in stroke and cerebrovascular injury, mechanistic hypotheses linking sleep with brain health and biomarker data (blood-based, cerebrospinal fluid-based, and imaging) suggest direct links to Alzheimer disease-specific pathology. These potential mechanisms and the increasing understanding of the "glymphatic system," and the recognition of the importance of sleep in poststroke recovery, as well, support a biological basis for the indirect (through the worsening of vascular disease) and direct (through specific effects on neuropathology) connections between sleep disorders and brain health. Given promising evidence for the benefits of treatment and prevention, sleep disorders and disturbances represent potential targets for early treatment that may improve brain health more broadly. In this scientific statement, we discuss the evidence supporting an association between sleep disorders and disturbances and poor brain health ranging from stroke to dementia and opportunities for prevention and early treatment.

Post-Stroke Brain Health Monitoring and Optimization: A Narrative Review

Significant advancements have been made in recent years in the acute treatment and secondary prevention of stroke. However, a large proportion of stroke survivors will go on to have enduring physical, cognitive, and psychological disabilities from suboptimal post-stroke brain health. Impaired brain health following stroke thus warrants increased attention from clinicians and researchers alike. In this narrative review based on an open timeframe search of the PubMed, Scopus, and Web of Science databases, we define post-stroke brain health and appraise the body of research focused on modifiable vascular, lifestyle, and psychosocial factors for optimizing post-stroke brain health. In addition, we make clinical recommendations for the monitoring and management of post-stroke brain health at major post-stroke transition points centered on four key intertwined domains: cognition, psychosocial health, physical functioning, and global vascular health. Finally, we discuss potential future work in the field of post-stroke brain health, including the use of remote monitoring and interventions, neuromodulation, multi-morbidity interventions, enriched environments, and the need to address inequities in post-stroke brain health. As post-stroke brain health is a relatively new, rapidly evolving, and broad clinical and research field, this narrative review aims to identify and summarize the evidence base to help clinicians and researchers tailor their own approach to integrating post-stroke brain health into their practices.

Association of serum uric acid with all-cause and cardiovascular mortality in obstructive sleep apnea

The study investigated the association between Serum Uric Acid (SUA) levels and all-cause as well as cardiovascular mortality in patients with Obstructive Sleep Apnea (OSA). This prospective cohort study enrolled participants with OSA from four cycles of the National Health and Nutrition Examination Survey (NHANES) conducted between 2005 and 2008, and 2015-2018. A weighted Cox proportional hazards model was used to assess adjusted hazard ratios (aHRs) and their corresponding 95% confidence intervals (CI) for all-cause and cardiovascular mortality. Additionally, multivariable logistic regression and restricted cubic splines (RCS) models were employed to examine nonlinear relationships between SUA and all-cause and cardiovascular mortality. Among the 5,584 OSA participants included in the study, covering the four NHANES cycles and with a median follow-up of 4.333 years, a total of 537 deaths were observed, including 108 deaths attributed to cardiovascular disease. Comparing the fourth quartile (Q4) of uric acid levels, both the fifth quartile (Q5) (aHRs = 1.51, 95% CI [1.08, 2.12]) and the second quartile (Q2) (aHRs = 1.53, 95% CI [1.04, 2.25]) of uric acid levels were independently associated with an increased risk of all-cause mortality. Furthermore, comparing the fourth quartile (Q4) of uric acid levels, the second quartile (Q2) (aHRs = 2.40, 95% CI [1.08, 5.35]) of uric acid levels were independently associated with an increased risk of cardiovascular mortality. The RCS model demonstrated a U-shaped pattern in the association between SUA and all-cause mortality in OSA, with an inflection point observed at 5.83 mg/dl. The findings of this study suggest a U-shaped association between serum SUA levels and all-cause mortality and nonlinearity association between serum SUA levels and all-cause mortality. Further studies are warranted to determine the causal relationship between SUA levels and all-cause and cardiovascular mortality.

The multifaceted aspects of sleep and sleep-wake disorders following stroke

Sleep-wake disorders (SWD) are acknowledged risk factors for both ischemic stroke and poor cardiovascular and functional outcome after stroke. SWD are frequent following stroke, with sleep apnea (SA) being the most frequent SWD affecting more than half of stroke survivors. While sleep disturbances and SWD are frequently reported in the acute phase, they may persist in the chronic phase after an ischemic stroke. Despite the frequency and risk associated with SWD following stroke, screening for SWD remains rare in the clinical setting, due to challenges in the assessment of post-stroke SWD, uncertainty regarding the optimal timing for their diagnosis, and a lack of clear treatment guidelines (i.e., when to treat and the optimal treatment strategy). However, little evidence support the feasibility of SWD treatment even in the acute phase of stroke and its favorable effect on long-term cardiovascular and functional outcomes. Thus, sleep health recommendations and SWD treatment should be systematically embedded in secondary stroke prevention strategy. We therefore propose that the management of SWD associated with stroke should rely on a multidisciplinary approach, with an integrated diagnostic, treatment, and follow-up strategy. The challenges in the field are to improve post-stroke SWD diagnosis, prognosis and treatment, through a better appraisal of their pathophysiology and temporal evolution.

Effectiveness and feasibility of continuous positive airway pressure in patients with stroke and sleep apnea: a meta-analysis of randomized trials

STUDY OBJECTIVES

This meta-analysis aimed to investigate the feasibility and effectiveness of continuous positive airway pressure (CPAP) treatment in stroke patients with sleep apnea.

METHODS

PubMed, EMBASE, and the Cochrane Library were searched from inception until July 28, 2022, for randomized controlled trials comparing the use of CPAP and usual treatment in patients with stroke or transient ischemic attack and sleep apnea. The primary outcome measures were the feasibility of CPAP therapy, neurological function, and functional status.

RESULTS

After screening 5,747 studies, 14 studies with 1,065 patients were included in this meta-analysis. Overall, 8 of the 14 studies recorded CPAP use, and the mean CPAP use was 4.47 hours per night (95% confidence interval [CI]: 3.85-5.09). The risk ratio of discontinuing CPAP was 1.50 (95% CI: 0.76-2.94; P = .24). Analysis of the neurofunctional scales showed that CPAP treatment improved neurological function (standardized mean difference: 0.28; 95% CI: 0.02-0.53), but there was substantial heterogeneity (I2 = 57%, P = .03) across the studies. CPAP treatment had no significant effect on functional status vs the control (standardized mean difference: 0.25; 95% CI: -0.01 to 0.51), but the studies also had substantial heterogeneity (I2 = 55%, P = .06).

CONCLUSIONS

CPAP treatment is feasible in patients with stroke and sleep apnea and may improve neurological outcomes in these patients. However, this finding should be interpreted with caution because of the substantial heterogeneity of current trials.

CITATION

Fu S, Peng X, Li Y, Yang L, Yu H. Effectiveness and feasibility of continuous positive airway pressure in patients with stroke and sleep apnea: a meta-analysis of randomized trials. J Clin Sleep Med. 2023;19(9):1685-1696.

Positive airway pressure treatment for sleep-disordered breathing is rare during the first year after stroke: The BASIC project

OBJECTIVE/BACKGROUND

Sleep-disordered breathing (SDB) is very common after ischemic stroke, and its treatment may have a positive impact on recovery from stroke and on secondary stroke prevention. This study sought to determine the prevalence of positive airway pressure (PAP) use after stroke.

PATIENTS/METHODS

Participants in the Brain Attack Surveillance in Corpus Christi (BASIC) project underwent a home sleep apnea test shortly after ischemic stroke. Demographics and co-morbidities were ascertained from the medical record. Self-reported PAP use (present vs absent) was assessed at 3, 6, and 12 months after stroke. Fisher exact tests and t-tests were used to compare PAP users versus non-users.

RESULTS

Of 328 participants who were found to have SDB after stroke, only 20 (6.1%) indicated using PAP at any point during the 12-month follow up period. High pre-stroke sleep apnea risk based on Berlin Questionnaire score, neck circumference, and co-morbid atrial fibrillation were associated with any self-reported PAP use; race/ethnicity, insurance status and other demographic variables were not associated with PAP use.

CONCLUSIONS

Only a small proportion of individuals with ischemic stroke and SDB received treatment with PAP during the initial year after stroke among participants in this population-based cohort study in Nueces County, Texas. Closing the substantial treatment gap for SDB after stroke might improve sleepiness and neurologic recovery.

Disparities in brain health comorbidity management in intracerebral hemorrhage

Background

Intracerebral hemorrhage (ICH) disproportionally affects underserved populations, and coincides with risk factors for cardiovascular events and cognitive decline after ICH. We investigated associations between social determinants of health and management of blood pressure (BP), hyperlipidemia, diabetes, obstructive sleep apnea (OSA), and hearing impairment before and after ICH hospitalization.

Methods

Survivors of the Massachusetts General Hospital longitudinal ICH study between 2016 and 2019 who received healthcare at least 6 months after ICH were analyzed. Measurements of BP, LDL and HbA1c and their management in the year surrounding ICH and referrals for sleep studies and audiology up to 6 months after ICH were gathered from electronic health records. The US-wide area deprivation index (ADI) was used as proxy for social determinants of health.

Results

The study included 234 patients (mean 71 years, 42% female). BP measurements were performed in 109 (47%) before ICH, LDL measurements were performed in 165 (71%), and HbA1c measurements in 154 (66%) patients before or after ICH. 27/59 (46%) with off-target LDL and 3/12 (25%) with off-target HbA1c were managed appropriately. Of those without history of OSA or hearing impairment before ICH, 47/207 (23%) were referred for sleep studies and 16/212 (8%) to audiology. Higher ADI was associated with lower odds of BP, LDL, and HbA1c measurement prior to ICH [OR 0.94 (0.90-0.99), 0.96 (0.93-0.99), and 0.96 (0.93-0.99), respectively, per decile] but not with management during or after hospitalization.

Conclusion

Social determinants of health are associated with pre-ICH management of cerebrovascular risk factors. More than 25% of patients were not assessed for hyperlipidemia and diabetes in the year surrounding ICH hospitalization, and less than half of those with off-target values received treatment intensification. Few patients were evaluated for OSA and hearing impairment, both common among ICH survivors. Future trials should evaluate whether using the ICH hospitalization to systematically address co-morbidities can improve long-term outcomes.

The mobile sleep medicine model in neurologic practice: Rationale and application

Background

Undiagnosed obstructive sleep apnea (OSA) is prevalent in neurological practice and significantly contributes to morbidity and mortality. OSA is prevalent in US adults and causes poor quality sleep and significant neurocognitive, cardiovascular, and cerebrovascular impairments. Timely treatment of OSA reduces cardio-cerebrovascular risks and improves quality of life. However, most of the US population has limited systematic access to sleep medicine care despite its clinical significance.

Focus

We discuss the importance of systematic screening, testing, and best-practice management of OSA and hypoventilation/hypoxemia syndromes (HHS) in patients with stroke, neurocognitive impairment, and neuromuscular conditions. This review aims to introduce and describe a novel integrated Mobile Sleep Medicine (iMSM) care model and provide the rationale for using an iMSM in general neurological practice to assist with systematic screening, testing and best-practice management of OSA, HHS, and potentially other sleep conditions.

Key points

The iMSM is an innovative, patient-centered, clinical outcome-based program that uses a Mobile Sleep Medicine Unit—a “sleep lab on wheels”—designed to improve access to OSA management and sleep care at all levels of health care system. The protocol for the iMSM care model includes three levels of operations to provide effective and efficient OSA screening, timely testing/treatment plans, and coordination of further sleep medicine care follow-up. The iMSM care model prioritizes effective, efficient, and patient-centered sleep medicine care; therefore, all parties and segments of care that receive and provide clinical sleep medicine services may benefit from adopting this innovative approach.

[Obstructive Sleep Apnea]

Obstructive sleep apnea (OSA) is defined as the presence of an apnea-hyponea index (AHI)>15/h, predominantly obstructive or AHI greater than 5 with symptoms, the classic symptoms are observed apneas, daytime sleepiness and snoring, however, there are many other associated symptoms. To assess the severity of OSA, classically, only the AHI value was considered, but there is increasing evidence to implicate other factors. The predisposition to develop OSA is determined by anatomical and functional features. Having OSA increases the risk of accidents, high blood pressure (HBP) and is associated with cardiovascular risk, diabetes mellitus (DM), cardiac arrhythmia and neoplasms. To assess the probability of OSA, questionnaires and scales have been developed to assess symptoms, the certain diagnosis is obtained by polysomnography (PSG), which is the gold standard test, or polygraphy, which is a simpler and more accessible diagnostic test for diagnosis validated, the use of one or the other will depend on the suspicion and the associated comorbidities. Treatments for sleep apnea increasingly tend to be more individualized based on the characteristics of the patient and all are complementary. Hygienic-dietary measures should be applied in all patients, continuous positive airway pressure (CPAP) is the most effective treatment and with the most evidence, but other treatments are also available such as mandibular advancement devices (MAD), postural therapy and surgical options among others. Telemedicine is advancing in the follow-up of patients with OSA, both from non-face-to-face consultations and control of equipment via Wi-Fi to assess adherence, efficacy and correct control of therapy.

Sleep and Stroke: Opening Our Eyes to Current Knowledge of a Key Relationship

PURPOSE OF REVIEW

To elucidate the interconnection between sleep and stroke.

RECENT FINDINGS

Growing data support a bidirectional relationship between stroke and sleep. In particular, there is strong evidence that sleep-disordered breathing plays a pivotal role as risk factor and concur to worsening functional outcome. Conversely, for others sleep disorders (e.g., insomnia, restless legs syndrome, periodic limb movements of sleep, REM sleep behavior disorder), the evidence is weak. Moreover, sleep disturbances are highly prevalent also in chronic stroke and concur to worsening quality of life of patients. Promising novel technologies will probably allow, in a near future, to guarantee a screening of commonest sleep disturbances in a larger proportion of patients with stroke. Sleep assessment and management should enter in the routinary evaluation of stroke patients, of both acute and chronic phase. Future research should focus on the efficacy of specific sleep intervention as a therapeutic option for stroke patients.

Sleep apnoea and ischaemic stroke: current knowledge and future directions

Sleep apnoea, one of the most common chronic diseases, is a risk factor for ischaemic stroke, stroke recurrence, and poor functional recovery after stroke. More than half of stroke survivors present with sleep apnoea during the acute phase after stroke, with obstructive sleep apnoea being the most common subtype. Following a stroke, sleep apnoea frequency and severity might decrease over time, but moderate to severe sleep apnoea is nevertheless present in up to a third of patients in the chronic phase after an ischaemic stroke. Over the past few decades evidence suggests that treatment for sleep apnoea is feasible during the acute phase of stroke and might favourably affect recovery and long-term outcomes. Nevertheless, sleep apnoea still remains underdiagnosed and untreated in many cases, due to challenges in the detection and prediction of post-stroke sleep apnoea, uncertainty as to the optimal timing for its diagnosis, and a scarcity of clear treatment guidelines (ie, uncertainty on when to treat and the optimal treatment strategy). Moreover, the pathophysiology of sleep apnoea associated with stroke, the proportion of stroke survivors with obstructive and central sleep apnoea, and the temporal evolution of sleep apnoea subtypes following stroke remain to be clarified. To address these shortcomings, the management of sleep apnoea associated with stroke should be integrated into a multidisciplinary diagnostic, treatment, and follow-up strategy.

SLEAP SMART (Sleep Apnea Screening Using Mobile Ambulatory Recorders After TIA/Stroke): A Randomized Controlled Trial

BACKGROUND AND PURPOSE

Poststroke/transient ischemic attack obstructive sleep apnea (OSA) is prevalent, linked with numerous unfavorable health consequences, but remains underdiagnosed. Reasons include patient inconvenience and costs associated with use of in-laboratory polysomnography (iPSG), the current standard tool. Fortunately, home sleep apnea testing (HSAT) can accurately diagnose OSA and is potentially more convenient and cost-effective compared with iPSG. Our objective was to assess whether screening for OSA in patients with stroke/transient ischemic attack using HSAT, compared with standard of care using iPSG, increased diagnosis and treatment of OSA, improved clinical outcomes and patient experiences with sleep testing, and was a cost-effective approach.

METHODS

We consecutively recruited 250 patients who had sustained a stroke/transient ischemic attack within the past 6 months. Patients were randomized (1:1) to use of (1) HSAT versus (2) iPSG. Patients completed assessments and questionnaires at baseline and 6-month follow-up appointments. Patients diagnosed with OSA were offered continuous positive airway pressure. The primary outcome was compared between study arms via an intention-to-treat analysis.

RESULTS

At 6 months, 94 patients completed HSAT and 71 patients completed iPSG. A significantly greater proportion of patients in the HSAT arm were diagnosed with OSA (48.8% versus 35.2%, P=0.04) compared with the iPSG arm. Furthermore, patients assigned to HSAT, compared with iPSG, were more likely to be prescribed continuous positive airway pressure (40.0% versus 27.2%), report significantly reduced sleepiness, and a greater ability to perform daily activities. Moreover, a significantly greater proportion of patients reported a positive experience with sleep testing in the HSAT arm compared with the iPSG arm (89.4% versus 31.1%). Finally, a cost-effectiveness analysis revealed that HSAT was economically attractive for the detection of OSA compared with iPSG.

CONCLUSIONS

In patients with stroke/transient ischemic attack, use of HSAT compared with iPSG increases the rate of OSA diagnosis and treatment, reduces daytime sleepiness, improves functional outcomes and experiences with sleep testing, and could be an economically attractive approach.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02454023.