Treatment of obstructive sleep apnoea with nasal continuous positive airway pressure in stroke

Obstructive Sleep apnea and cardiovascular events in Elderly Patients

INTRODUCTION

In recent decades, life expectancy has increased considerably. The cardiovascular effects of Obstructive Sleep Apnea (OSA) in the elderly lead to patient disability and high resource consumption. Intermittent nocturnal hypoxia leads to hemodynamic stress and adrenergic activation, which promotes cardiovascular disease. However, chronic intermittent hypoxia may protect elderly patients from cardiovascular events (CVE) due to biological adaptation.

AREAS COVERED

OSA patients are at increased risk of cardiovascular events. The severity of OSA increases cardiovascular risk, and this association also exists in the elderly. This article reviews the association between OSA, CPAP treatment, and CVE, particularly stroke and coronary heart disease (CHD), in the elderly. MEDLINE and the Cochrane Collaboration databases were searched from inception to July 2021.

EXPERT COMMENTARY

Although a positive association between OSA and the incidence of cardiovascular disease in the elderly has been established, the role of sleep apnea in certain cardiovascular events remains controversial. Most authors agree that untreated OSA is a risk factor for stroke or worse stroke prognosis. However, the association between OSA and CHD is usually less pronounced than between OSA and stroke, especially in the elderly.

Incidence and predictors of adherence to sleep apnea treatment in rehabilitation inpatients with acquired brain injury

OBJECTIVE

The purpose of this study was to describe incidence and assess predictors of adherence to Positive Airway Pressure (PAP) therapy for Obstructive Sleep Apnea (OSA) in persons with acquired brain injury (ABI).

METHODS

A 2012-2015 retrospective analysis of consecutive ABI patients admitted for neurorehabilitation, referred for polysomnography (PSG), and prescribed PAP for OSA. Univariable linear regressions were conducted to examine predictors of average hours of nightly PAP use. Univariable logistic regressions were conducted to examine predictors of PAP adherence using the conventional clinical definition of ≥4 h per night ≥70% of the time. Persons with traumatic etiology were separately analyzed.

RESULTS

ABI etiology was 51% traumatic, 36% stroke, and 13% other nontraumatic causes. Nearly two-thirds were nonadherent to PAP. For the overall sample, higher average nightly PAP usage was significantly predicted by positive hypertension diagnosis (β = 0.271, p = 0.019). Likewise, greater adherence based on the conventional cutoff was predicted by poorer motor functioning at hospital admission (OR = 0.98, p = 0.001) and lower oxygen saturation nadir (OR = 0.99, p = 0.003). For those with traumatic injuries, greater adherence was predicted by poorer functional status at hospital admission (OR = 0.98, p = 0.010) and positive hypertension diagnosis (OR = 0.16, p = 0.023).

CONCLUSIONS

In this study of hospitalized neurorehabilitation patients with ABI and comorbid OSA, predictors of adherence included lower oxygen saturation, poorer functional status and hypertension diagnosis, perhaps signifying the role of greater severity of illness on treatment adherence. High rates of refusal and nonadherence to frontline PAP therapy for sleep apnea is a concern for persons in recovery form ABI who are at a time of critical neural repair.

Evaluation of an OSA risk stratifying and treatment protocol during inpatient rehabilitation of post-stroke patients

PURPOSE

To evaluate outcomes, outside of a clinical trial setting, of a protocol utilizing overnight oximetry (NOx) to risk stratify post-stroke patients for obstructive sleep apnea (OSA) followed by autoadjusting continuous positive airway pressure (APAP) treatment in patients considered high risk for OSA.

METHODS

Retrospective observational study of post-stroke patients at an academic inpatient stroke rehabilitation facility. Patients underwent NOx, and those at high risk for OSA (oxygen desaturation index 3% > 10 per hour) were attempted on a trial of APAP, and further stratified into high risk adherent with treatment (HRAT) or high-risk failed treatment (HRFT). Change in functional independence measure (FIM) was used to assess recovery.

RESULTS

Two hundred twenty-four post-stroke patients underwent NOx, with 120 (53%) considered high risk for OSA. Twelve (10%) were compliant with APAP treatment (> 4 h/night on > 70% of nights). No difference in change in FIM scores was observed for HRAT versus HRFT [total FIM change - 5.8, 95% CI (- 13.9, 2.2); motor FIM change - 4.5, 95% CI (- 11.5, 2.4); cognitive FIM change - 1.3, 95% CI (-3.8, 1.2)]. A subgroup analysis matched 14 HRAT patients (using adherence criterion of APAP usage > 50% of nights) to 35 HRFT patients. A statistically significant, but clinically irrelevant, difference in total FIM change was observed (HRAT vs HRFT, difference between means - 5.2, p = 0.03).

CONCLUSIONS

The use of APAP in high-risk patients was poorly tolerated and did not improve post-stroke recovery. Further studies with larger sample sizes are needed to determine the effect of APAP treatment on short-term recovery.

Effect of CPAP Treatment of Sleep Apnea on Clinical Prognosis After Ischemic Stroke: An Observational Study

STUDY OBJECTIVES

To evaluate continuous positive airway pressure (CPAP) treatment in patients with moderate to severe sleep-disordered breathing (SDB) after an ischemic stroke.

METHODS

We identified patients included in the Acute Stroke Registry and Analysis of Lausanne (ASTRAL) who underwent polysomnography after an ischemic stroke. We compared patients without significant SDB (apnea-hypopnea index [AHI] < 15 events/h: SDB-), with AHI ≥ 15 events/h who refused CPAP or with poor CPAP adherence (SDB+ CPAP-), and patients with SDB effectively treated by CPAP (SDB+ CPAP+).

RESULTS

We analyzed data from 101 patients (age 68.5 ± 11.1 years, 84.1% men). In multivariate analysis the SDB+ CPAP+ group was associated with a significant reduction of stroke recurrence and mortality (odds ratio 0.13, 95% confidence interval 0.00-0.86, P = .031), whereas atrial fibrillation was independently associated with a higher risk (odds ratio 4.32, 95% confidence interval 1.51-12.33, P = .006). Event-free survival analysis (stroke recurrence and death) after 2-year follow-up showed that those in the SDB+ CPAP+ group had significantly higher cardiovascular survival, and Cox proportion hazard model identified CPAP treatment as significantly associated with survival time (P = .025). The AHI and the National Institutes of Health Stroke Scale subacute score were independently associated with CPAP adherence among patients with SDB.

CONCLUSIONS

This observational study shows that CPAP treatment in stroke patients with moderate to severe SDB is associated with lower rates of stroke recurrence and death.

The estimation of excessive daytime sleepiness in post-stroke patients - a polysomnographic study

Excessive daytime sleepiness (EDS) has been reported in stroke patients. EDS in acute stroke was studied repeatedly, but there is a modest amount of data in post-stroke patients. The aim of this study was to assess the frequency of EDS and characterize sleep architecture in patients >3 months after stroke and identify factors which may affect EDS. 66 patients were enrolled, of which 33 had experienced stroke. All underwent a standardized overnight, diagnostic single night polysomnography, including electrocephalogram (EEG) leads, electrooculograms (EOG), chin electromyogram (EMG), and electrocardiogram (ECG). Epworth Sleepiness Scale (ESS) was used to measure subjects' level of daytime sleepiness. We observed similar total ESS score, total sleep time (TST), sleep efficiency, as well as respiratory disturbance index /apnea-hypopnea index (RDI/AHI), oxygen desaturation index (ODI) and mean heart rate in both groups. We observed positive linear correlation between EDS and mean heart rate in the stroke group (r = 0.46, p < 0.05) as well as between EDS and REM duration (r = 0.23, p < 0.05). In the non-stroke group EDS didn't correlate with the heart rate or with the REM duration. In the non-stroke group EDS correlated positively with RDI/AHI and ODI index (r = 0.46; p = <0.05 r = 0.41, p < 0.05 and maximal desaturation (r = 0.55, p < 0.05), this correlation was not observed in post-stroke group. In the both groups we observed negative linear correlation between BMI and saturation (stroke group - mean as well as minimal saturation (r = -0.458, p < 0.05; r = -0.578, p < 0.05), non stroke group - minimal but not mean saturation rate (r = -0.544, p < 0.05). We also noticed in both groups positive correlation between BMI and both AHI and ODI index (stroke group respectively: r = 0.430, p < 0.05; r = 0.451, p < 0.05; non-stroke group - BMI and ODI: r = 0.405, p < 0.05). The positive BMI correlation with RDI/AHI was not significant in the non-stroke group. We noticed that BMI correlates with non-REM sleep N1 (r = 0.760, p < 0.05) in post-stroke group, while it correlates negatively with REM sleep (r = -0.709, p < 0.05). There was no such correlation in the non-stroke group. In summary, in stroke patients subjective daytime sleepiness is associated with heart rate, but not with the severity of OSA. Thus ESS (Epworth Scale Score) may be not as useful as a marker of obstructive sleep apnea (OSA) presence or severity in post stroke patient as in the general population.

Systematic Review Investigating the Effects of Nonpharmacological Interventions During Sleep to Enhance Physical Rehabilitation Outcomes in People With Neurological Diagnoses

OBJECTIVE

Conduct a systematic review of nonpharmacological interventions applied during sleep to enhance physical rehabilitation outcomes of individuals with a neurological diagnosis.

DATA SOURCES

Three online databases were searched for original research.

STUDY SELECTION

Intervention studies were included that used outcome measures of impairment, activity, and/or participation.

DATA EXTRACTION

Two reviewers independently screened 2287 titles and abstracts, reviewed 101 full texts, extracted data, and assessed study quality and risk of bias for 9 included studies.

DATA SYNTHESIS

All included studies were randomized controlled trials involving continuous positive airway pressure (CPAP) with inpatient individuals with stroke and sleep apnea. Several studies also included long-term outpatient follow-ups. Results in terms of outcomes based on impairment, activity, and participation were mixed. However, several studies found that the use of CPAP following stroke and sleep apnea during early stroke recovery had benefits relative to no CPAP.

CONCLUSIONS

The only nonpharmacological intervention to be administered during sleep in a neurological population to improve physical rehabilitation outcomes was found to be CPAP. This review was complicated by the variety of outcome measures used, lack of physical rehabilitation description, and CPAP compliance. In general, participants who had acceptable to good CPAP compliance saw the largest improvements in physical rehabilitation outcomes. Several other promising methods of brain stimulation during sleep are discussed.

Role of Positive Airway Pressure Therapy for Obstructive Sleep Apnea in Patients With Stroke: A Randomized Controlled Trial

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is an independent risk factor for stroke. The objective of this study was to assess the effect of continuous positive airway pressure (CPAP) treatment on prevention of new vascular events among patients with stroke and OSA.

METHODS

Consecutive conscious patients presenting with first imaging-confirmed arterial stroke were included, 6 weeks or more after ictus. All patients underwent clinical and polysomnography (PSG) testing. Patients with an apnea-hypopnea index (AHI) of > 15 events/h were randomized to posttitration nightly CPAP treatment and non-CPAP (received best medical treatment) groups. On follow-up at 3, 6, and 12 months from randomization, evaluation was carried out for any new vascular events as the primary outcome measure, and for clinical stroke outcomes (using the Barthel Index and modified Rankin scale) and neuropsychological parameters as the secondary outcome measures.

RESULTS

Among the 679 patients with stroke who were screened, 116 reported for PSG, 83 had AHI > 15 events/h, and 70 (34 in CPAP and 36 in non-CPAP) were randomized. Thirteen patients could not be randomized because of a lack of CPAP devices. Four patients crossed over from the CPAP to the non-CPAP group. Age (mean age 53.41 ± 9.85 in CPAP versus 52.69 ± 13.23 years in non-CPAP, P = .81) and sex distribution (24 males in CPAP versus 33 males in non-CPAP, P = .79) were similar in both groups. At 12-month follow-up, there was 1 vascular event (3.33%) in the CPAP group and 6 events (15%) in the non-CPAP group (P = .23). Modified Rankin scale score improvement by ≥ 1 at 12-month follow-up was found in significantly more patients in the CPAP group than in the non-CPAP group (53% versus 27%).

CONCLUSIONS

These findings suggest significantly better stroke outcomes and statistically nonsignificant favorable outcomes in terms of recurrence of vascular events for patients with stroke and OSA who use CPAP treatment.

CLINICAL TRIAL REGISTRATION

Registry: Clinical Trials Registry - India, CTRI Registration No: CTRI/2016/07.007104, Title: Sleep Disordered Breathing in stroke patients: Effect of treatment trial, URL: http://ctri.nic.in/Clinicaltrials/showallp.php?mid1=8682&EncHid=&userName=sleep%20disordered%20breathing.

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

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

Assistive technology to enable sleep function in patients with acquired brain injury: Issues and opportunities

Introduction

Sleep disorders in patients with acquired brain injury are highly burdensome and associated with disability. An assistive technology framework emphasises the need to develop and apply a broad range of devices, strategies, and practices to ameliorate disabilities. We aimed to summarise scientific evidence regarding the utility of assistive technology in managing sleep disorders in patients with various causes of acquired brain injury.

Method

We retrieved articles before January 2016, through database searches of Medline, Embase, PsycINFO, CINAHL, and various bibliographies. The person–environment–occupation framework was used to analyse complex data pertaining to technology application and utility.

Results

We found 21 studies that described seven assistive technologies (continuous positive airway pressure, adaptive servo ventilator, nasotracheal suction mechanical ventilation, positioning devices, cognitive behavioural therapy, light therapy, and acupuncture) utilised in patients with acquired brain injury to manage sleep disorders.

Conclusion

Assistive technologies demonstrated effectiveness in alleviating and/or managing sleep disorders after acquired brain injury. Adherence to using the technology is limited by the level of injury-induced cognitive and physical impairment, technological regime, and environmental support. Development of user-friendly sleep-assistive technologies that take into consideration functional limitations and practice guidelines on structural communication between the occupational therapist, patient, and caregiver may facilitate patients’ self-determination in managing sleep disorders.

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.

A Comparison of Different Success Definitions in Non-Continuous Positive Airway Pressure Treatment for Obstructive Sleep Apnea Using Cardiopulmonary Coupling

STUDY OBJECTIVES

The definition and the criteria for the successful treatment of obstructive sleep apnea vary, depending on the study. This study aimed to compare different success criteria of non-continuous positive airway pressure (non-CPAP) treatment for obstructive sleep apnea in terms of sleep quality by using cardiopulmonary coupling.

METHODS

We included 98 patients who had been treated with sleep surgery or with a mandibular advancement device at our sleep clinic from January 2011 to March 2013. The success and failure groups were divided by 6 criteria that have been used in the literature. The validity of each of the 6 criteria was evaluated by cardiopulmonary coupling-based sleep quality.

RESULTS

The parameters of cardiopulmonary coupling indicated that sleep quality improved with non-CPAP treatment: low-frequency coupling decreased from 57.4% ± 17.7% to 46.9% ± 16.5%, whereas high-frequency coupling increased from 30.2% ± 17.1% to 37.4% ± 16.7%. In multiple regression analysis, only the criterion of a reduction in the apnea-hypopnea index greater than 50% was significantly associated with sleep quality improvement (p = 0.016; 95% confidence interval, 1.008-1.076 in the high-frequency coupling increment; p = 0.001; 95% confidence interval, 1.025-1.099 in the low-frequency coupling decrement).

CONCLUSIONS

Cardiopulmonary coupling analysis showed that a reduction in the apnea-hypopnea index of more than 50% might be the optimal criterion to determine the success or failure of non-CPAP treatment in terms of sleep quality.

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

PURPOSE/OBJECTIVES

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

DESCRIPTION OF THE PROJECT

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

OUTCOMES

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

CONCLUSIONS

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

Effect of Continuous Positive Airway Pressure on Stroke Rehabilitation: A Pilot Randomized Sham-Controlled Trial

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) predicts poor functional outcome after stroke and increases the risk for recurrent stroke. Less is known about continuous positive airway pressure (CPAP) treatment on stroke recovery.

METHODS

In a pilot randomized, double-blind, sham-controlled trial, adult stroke rehabilitation patients were assigned to auto-titrating or sham CPAP without diagnostic testing for OSA. Change in Functional Independence Measure (FIM), a measure of disability, was assessed between rehabilitation admission and discharge.

RESULTS

Over 18 months, 40 patients were enrolled and 10 withdrew from the study: 7 from active and 3 from sham CPAP (p > 0.10). For the remaining 30 patients, median duration of CPAP use was 14 days. Average CPAP use was 3.7 h/night, with at least 4 h nightly use among 15 patients. Adherence was not influenced by treatment assignment or stroke severity. In intention-to-treat analyses (n = 40), the median change in FIM favored active CPAP over sham but did not reach statistical significance (34 versus 26, p = 0.25), except for the cognitive component (6 versus 2.5, p = 0.04). The on-treatment analyses (n = 30) yielded similar results (total FIM: 32 versus 26, p = 0.11; cognitive FIM: 6 versus 2, p = 0.06).

CONCLUSIONS

A sham-controlled CPAP trial among stroke rehabilitation patients was feasible in terms of recruitment, treatment without diagnostic testing and adequate blinding-though was limited by study retention and CPAP adherence. Despite these limitations, a trend towards a benefit of CPAP on recovery was evident. Tolerance and adherence must be improved before the full benefits of CPAP on recovery can be assessed in larger trials.

Post-stroke depression, obstructive sleep apnea, and cognitive impairment: Rationale for, and barriers to, routine screening

Stroke can cause neurological impairment ranging from mild to severe, but the impact of stroke extends beyond the initial brain injury to include a complex interplay of devastating comorbidities including: post-stroke depression, obstructive sleep apnea, and cognitive impairment (“DOC”). We reviewed the frequency, impact, and treatment options for each DOC condition. We then used the Ottawa Model of Research Use to examine gaps in care, understand the barriers to knowledge translation, identification, and addressing these important post-stroke comorbidities. Each of the DOC conditions is common and result in poorer recovery, greater functional impairment, increased stroke recurrence and mortality, even after accounting for traditional vascular risk factors. Despite the strong relationships between DOC comorbidities and these negative outcomes as well as recommendations for screening based on best practice recommendations from several countries, they are frequently not assessed. Barriers related to the nature of the screening tools (e.g., time consuming in high-volume clinics), practice environment (e.g., lack of human resources or space), as well as potential adopters (e.g., equipoise surrounding the benefits of treatment for these conditions) pose challenges to routine screening implementation. Simple, feasible approaches to routine screening coupled with appropriate, evidence-based treatment protocols are required to better identify and manage depression, obstructive sleep apnea, and cognitive impairment symptoms in stroke prevention clinic patients to reduce the impact of these important post-stroke comorbidities. These tools may in turn facilitate large-scale randomized controlled treatment trials of interventions for DOC conditions that may help to improve cardiovascular outcomes after stroke or TIA.

Obstructive sleep apnea: a new preventive and therapeutic target for stroke: a new kid on the block

Stroke is the second leading cause of death worldwide and a major cause of mental and physical impairment. Numerous studies have identified risk factors for stroke, including hypertension, atrial fibrillation, diabetes, and smoking. However, even after considering these well-recognized risk factors, there is substantial variation in stroke rates and stroke-related outcomes. There is emerging evidence that obstructive sleep apnea increases the risk of stroke independently of traditional risk factors. Obstructive sleep apnea is present in the majority of patients with stroke and contributes to persistent neurologic impairment. Early recognition and treatment of obstructive sleep apnea during the post-stroke period lead to better neurologic outcome. Healthcare providers should be aware of the strong association of obstructive sleep apnea as a risk factor for stroke and its effect on neurologic recovery. The presence of hypertension and diabetes-the 2 most common comorbid conditions in obstructive sleep apnea-should prompt diagnostic workup for and treatment of obstructive sleep apnea as a way of primary and secondary prevention of stroke.

Sleep Apnea and Stroke

Stroke is the second leading cause of death worldwide and often has devastating consequences for affected individuals in terms of chronic disability. Traditional risk factors such as age, male sex, ethnicity, hypertension, and atrial fibrillation explain 60%-80% of the risk of stroke. Obstructive sleep apnea (OSA) is highly prevalent in individuals who have had a stroke and its emerging role as a potential modifiable risk factor for stroke has been recognized in the most recent American Heart Association stroke guidelines, which recommend consideration of screening for and treatment of OSA in this regard. In this article we provide an overview of the current evidence-based knowledge related to stroke and sleep apnea. The main focus of this article is key pathophysiological mechanisms by which OSA might increase the risk for stroke. The effect of OSA on stroke outcomes and the efficacy of treatment of OSA on these outcomes is also discussed.

Treatment of obstructive sleep apnea syndrome associated with stroke

The association between sleep-disordered breathing and stroke has been a subject of increased interest and research. Obstructive sleep apnea (OSA) is an important risk factor for stroke incidence and mortality. Moreover, OSA is a common clinical outcome after stroke, directly influencing the patient's recovery. The treatment of choice for OSA is positive airway pressure (PAP) support and the PAP appliance is considered the most recommended clinical management for the treatment of patients with cardiovascular complications. However, the implementation of PAP in stroke patients remains a challenge, considering the increased frequency of motor and language impairments associated with the cerebrovascular event. In the present study, we reviewed the main findings describing the association between stroke and OSA treatment with continuous positive airway pressure. We also discussed the types of OSA treatment, the different options and indications of PAP treatment, PAP adherence and the clinical outcomes after treatment.

Screening sleep disordered breathing in stroke unit

In acute stroke, OSA has been found to impair rehabilitation and increase mortality but the effect of central apnea is more unclear. The aim of the present study was to evaluate the feasibility of using limited ambulatory recording system (sleep mattress to evaluate nocturnal breathing and EOG-electrodes for sleep staging) in sleep disordered breathing (SDB) diagnostics in mild acute cerebral ischemia patients and to discover the prevalence of various SDB-patterns among these patients. 42 patients with mild ischemic stroke or transient ischemic attack were studied. OSA was found in 22 patients (52.4%). Central apnea was found in two patients (4.8%) and sustained partial obstruction in only one patient (2.4%). Sleep staging with EOG-electrodes only yielded a similar outcome as scoring with standard rules. OSA was found to be common even after mild stroke. Its early diagnosis and treatment would be favourable in order to improve recovery and reduce mortality. Our results suggest that OSA can be assessed by a limited recording setting with EOG-electrodes, sleep mattress, and pulse oximetry.

Challenges and motivating factors related to positive airway pressure therapy for post-TIA and stroke patients

Challenges adapting to continuous positive airway pressure (CPAP) therapy are largely unexplored in patients with stroke or transient ischemic attack. This study, nested within a randomized controlled trial of CPAP use, employed qualitative methods to explore challenges and motivators related to CPAP at two time points: prior to initiating therapy and at a 1-month follow up. Emergent thematic analysis, an inductive, qualitative approach, revealed variations in how patients experienced and adapted to CPAP across five phases: (a) interpreting the sleep apnea diagnosis, (b) contemplating CPAP therapy, (c) trying CPAP therapy, (d) making mid-course adjustments, and (e) experiencing benefits from CPAP therapy. Patients all had mild to moderate sleep apnea, and frequently did not experience sleep apnea symptoms. A salient motivator for adhering to CPAP therapy for these patients was the desire to reduce the risk of subsequent cerebrovascular events. Self-determination theory guided the interpretation of results.

The effect of sleep disordered breathing on the outcome of stroke and transient ischemic attack: a systematic review

STUDY OBJECTIVES

The primary objective was to systematically review the literature on how sleep disordered breathing (SDB) affects recurrence and death among stroke or transient ischemic attack (TIA) patients. A secondary objective was to evaluate how treatment of SDB with continuous positive airway pressure (CPAP) affects the risk of recurrence and death in these patients.

METHODS

Adults (18+) with a stroke or TIA diagnosis were eligible for inclusion. Case groups consisted of patients with a sleep disorder. The outcomes of interest were all-cause mortality, recurrent vascular events, and case fatality.

RESULTS

Ten articles covering 1,203 stroke and TIA patients were included in the review. The results generally support a dose-response relationship between severity of SDB and risk of recurrent events and all-cause mortality in stroke and TIA patients. Three small-scale articles with substantial risk of bias evaluated the effects of CPAP therapy, and the results are inconclusive. Data on case fatality is too sparse to be conclusive.

CONCLUSIONS

Existing studies provide sufficient data to establish obstructive SDB as a negative predictor of all-cause mortality and recurrent vascular events following stroke or TIA. The ability of CPAP treatment to lower the risk of serious adverse outcomes after stroke remains controversial because of substantial risk of bias identified in most of the eligible studies addressing this relation. Additional studies are needed.

Capnography screening for sleep apnea in patients with acute stroke

Sleep apnea syndrome (SAS) is a prominent clinical feature in acute stroke patients. Diagnosis is usually established by polysomnography or cardio-respiratory polygraphy (CRP). Both diagnostic procedures produce high costs, are dependent on the access to a specialized sleep laboratory, and are poorly tolerated by patients with acute stroke. In this study we therefore investigated whether capnography may work as a simple screening tool in this context. In addition to conventional CRP, 27 patients with acute stroke were studied with capnography provided by our standard monitoring system. The trend graphs of the end-tidal CO(2) values (EtCO(2)) were used to determine the capnography-based estimate of the apnea-hypopnea index (AHI(CO2)). Index events were scored when the EtCO(2) value dropped for > 50% of the previous baseline value. We found that the AHI(CO2) correlated significantly with the apnea-hypopnea index measured with conventional CRP (AHI(CRP)) (r = 0.94; p < 0.001). An AHI(CO2) > 5 turned out to be highly predictive of an AHI(CRP) > 10. According to our findings, routinely acquired capnography may provide a reliable estimate of the AHI(CRP). The equipment needed for this screening procedure is provided by the monitoring systems of most intensive care units and stroke units where stroke patients are regularly treated during the first days of their illness. Therefore, early diagnosis of SAS in these patients is made substantially easier.

Obstructive sleep apnea and stroke

Obstructive sleep apnea (OSA) is a common disorder that has been associated with many cardiovascular disease processes, including hypertension and arrhythmias. OSA has also been identified as an independent risk factor for stroke and all-cause mortality. OSA is highly prevalent in patients with transient ischemic attacks and stroke. Routinely screening patients with transient ischemic attacks or stroke for sleep apnea is becoming more common. In stroke patients with OSA, treatment with continuous positive airway pressure may prevent subsequent cardiovascular events and improve neurologic outcomes. This review explores the pathophysiology of the association between OSA and stroke, and the clinical implications of identification and treatment of OSA in patients with stroke.

Sleep-Disordered Breathing in Acute Ischemic Stroke and Transient Ischemic Attack: Effects on Short- and Long-Term Outcome and Efficacy of Treatment with Continuous Positive Airways Pressure – Rationale and Design of the SAS Care Study

Objectives

Sleep-disordered breathing represents a risk factor for cardiovascular morbidity and mortality and negatively affects short-term and long-term outcome after an ischemic stroke or transient ischemic attack. The effect of continuous positive airways pressure in patients with sleep-disordered breathing and acute cerebrovascular event is poorly known. The SAS CARE 1 study assesses the effects of sleep-disordered breathing on clinical evolution, vascular functions, and markers within the first three-months after an acute cerebrovascular event. The SAS CARE 2 assesses the effect of continuous positive airways pressure on clinical evolution, cardiovascular events, and mortality as well as vascular functions and markers at 12 and 24 months after acute cerebrovascular event.

Methods

SAS CARE 1 is an open, observational multicenter study in patients with acute cerebrovascular event acutely admitted in a stroke unit: a sample of 200 acute cerebrovascular event patients will be included. Vascular functions and markers (blood pressure, heart rate variability, endothelial function by peripheral arterial tonometry and specific humoral factors) will be assessed in the acute phase and at three-months follow-up. SAS CARE 2 will include a sample of patients with acute cerebrovascular event in the previous 60–90 days. After baseline assessments, the patients will be classified according to their apnea hypopnea index in four arms: non-sleep-disordered breathing patients (apnea hypopnea index <10), patients with central sleep-disordered breathing, sleepy patients with obstructive apnea hypopnea index ≥20, which will receive continuous positive airways pressure treatment, nonsleepy patients with obstructive sleep-disordered breathing (apnea hypopnea index ≥20), which will be randomized to receive continuous positive airways pressure treatment or not.

Conclusions

The SAS CARE study will improve our understanding of the clinical sleep-disordered breathing in patients with acute cerebrovascular event and the feasibility/efficacy of continuous positive airways pressure treatment in selected patients with acute cerebrovascular event and sleep-disordered breathing.

Position paper on the management of patients with obstructive sleep apnea and hypertension: joint recommendations by the European Society of Hypertension, by the European Respiratory Society and by the members of European COST (COoperation in Scientific and Technological research) ACTION B26 on obstructive sleep apnea

This article is aimed at addressing the current state of the art in epidemiology, pathophysiology, diagnostic procedures and treatment options for appropriate management of obstructive sleep apnea (OSA) in cardiovascular (particularly hypertensive) patients, as well as for the management of cardiovascular diseases (particularly arterial hypertension) in OSA patients. The present document is the result of the work done by a panel of experts participating in the European Union COST (COoperation in Scientific and Technological research) ACTION B26 on OSA, with the endorsement of the European Respiratory Society (ERS) and the European Society of Hypertension (ESH). These recommendations are particularly aimed at reminding cardiovascular experts to consider the occurrence of sleep-related breathing disorders in patients with high blood pressure. They are at the same time aimed at reminding respiration experts to consider the occurrence of hypertension in patients with respiratory problems at night.

Continuous positive airway pressure: evaluation of a novel therapy for patients with acute ischemic stroke

BACKGROUND

New approaches are needed to treat patients with stroke. Among acute ischemic stroke patients, our primary objectives were to describe the prevalence of sleep apnea and demonstrate the feasibility of providing auto-titrating continuous positive airway pressure (auto-CPAP). A secondary objective was to examine the effect of auto-CPAP on stroke severity.

METHODS

Stroke patients randomized to the intervention group received 2 nights of auto-CPAP, but only those with evidence of sleep apnea received auto-CPAP for the remainder of the 30-day period. Intervention patients received polysomnography 30 days post-stroke. Control patients received polysomnography at baseline and after 30 days. Acceptable auto-CPAP adherence was defined as ≥ 4 h/night for ≥ 75% nights. Change in stroke severity was assessed comparing the NIH Stroke Scale (NIHSS) at baseline versus at 30 days.

RESULTS

The 2 groups (intervention N = 31, control N = 24) had similar baseline stroke severity (both median NIHSS, 3.0). Among patients with complete polysomnography data, the majority had sleep apnea: baseline, 13/15 (86.7%) control patients; 30 days, 24/35 (68.6%) control and intervention patients. Intervention patients had greater improvements in NIHSS (-3.0) than control patients (-1.0); P = 0.03. Among patients with sleep apnea, greater improvement was observed with increasing auto-CPAP use: -1.0 for control patients not using auto-CPAP; -2.5 for intervention patients with some auto-CPAP use; and -3.0 for intervention patients with acceptable auto-CPAP adherence.

CONCLUSIONS

The majority of acute stroke patients had sleep apnea. Auto-CPAP was well tolerated, appears to improve neurological recovery from stroke, and may represent a new therapeutic approach for selected patients with acute cerebral infarction.

Effect of transnasal insufflation on sleep disordered breathing in acute stroke: a preliminary study

BACKGROUND AND PURPOSE

Sleep disordered breathing (SDB) is frequent in acute stroke patients and is associated with early neurologic worsening and poor outcome. Although continuous positive airway pressure (CPAP) effectively treats SDB, compliance is low. The objective of the present study was to assess the tolerance and the efficacy of a continuous high-flow-rate air administered through an open nasal cannula (transnasal insufflation, TNI), a less-intrusive method, to treat SDB in acute stroke patients.

METHODS

Ten patients (age, 56.8 ± 10.7 years), with SDB ranging from moderate to severe (apnea-hypopnea index, AHI, >15/h of sleep) and on a standard sleep study at a mean of 4.8 ± 3.7 days after ischemic stroke (range, 1-15 days), were selected. The night after, they underwent a second sleep study while receiving TNI (18 L/min).

RESULTS

TNI was well tolerated by all patients. For the entire group, TNI decreased the AHI from 40.4 ± 25.7 to 30.8 ± 25.7/h (p = 0.001) and the oxygen desaturation index >3% from 40.7 ± 28.4 to 31 ± 22.5/h (p = 0.02). All participants except one showed a decrease in AHI. The percentage of slow-wave sleep significantly increased with TNI from 16.7 ± 8.2% to 22.3 ± 7.4% (p = 0.01). There was also a trend toward a reduction in markers of sleep disruption (number of awakenings, arousal index).

CONCLUSIONS

TNI improves SDB indices, and possibly sleep parameters, in stroke patients. Although these changes are modest, our findings suggest that TNI is a viable treatment alternative to CPAP in patients with SDB in the acute phase of ischemic stroke.

Management of sleep disorders in stroke

OPINION STATEMENT

Scientific studies have proven a very strong association between stroke and obstructive sleep apnea (OSA). The prevalence of OSA is very high in patients with acute stroke, and untreated OSA is a stroke risk factor. In the stroke patient population, symptoms of OSA may atypically appear as isolated insomnia, hypersomnia, a dysfunction of circadian rhythm, a parasomnia, or a sleep-related movement disorder. Thus, we believe that in patients with acute stroke, OSA should be addressed first, using full in-laboratory, attended polysomnography (PSG), before other specific sleep disorders are aggressively addressed with specific therapeutic interventions. When OSA is diagnosed, supportive techniques including the application of continuous positive airway pressure (CPAP) therapy, positional therapies, or both should be considered first-line treatments. If OSA is ruled out by PSG, the therapeutic emphasis for sleep-related complaints is routinely based on instituting good sleep hygiene practices and using cognitive behavioral techniques (cognitive therapies, sleep restriction, stimulus control, and progressive relaxation therapies) because patients with stroke may be prone to the adverse effects of many of the medications that are otherwise routinely prescribed for a variety of specific sleep disorders.

The relationship between sleep disorders and stroke

Although sleep appears to be a quiescent, passive state externally, there are a multitude of physiological changes occurring during sleep that can affect cerebral homeostasis and predispose individuals to cerebrovascular disorders. Therefore, it is not surprising that sleep-disordered breathing causes significant nocturnal perturbations, such as obstructive sleep apnea (OSA), that can lead to cerebrovascular disorders. There is evidence to suggest that OSA is a risk factor for stroke, although studies have not been able to clearly discern the absence or presence of OSA before the stroke event. Sleep-disordered breathing, such as OSA and central sleep apnea, can occur as a consequence of stroke. Fortunately, treating OSA appears to decrease morbidity and possibly mortality. Unfortunately, continuous positive airway pressure compliance in this population group is low, and significant efforts and resources may be needed to improve compliance and adherence. Various other sleep disorders, such as insomnia, fatigue, hypersomnia, and parasomnia, can occur following a stroke, and physicians treating patients following a stroke need to be aware of these disorders in order to effectively treat such patients.

Strokes and their relationship with sleep and sleep disorders

INTRODUCTION

In the current population, strokes are one of the most important causes of morbidity and mortality, to which new risk factors are increasingly being attributed. Of late, there is increased interest in the relationship between sleep disorders and strokes as regards risk and prognosis.

DEVELOPMENT

This article presents the changes in sleep architecture and brain activity in stroke patients, as well as the interaction between stroke and sleep disorders, including those which may also influence the outcome and recovery from strokes. The different treatments discussed in the literature are also reviewed, as correct treatment of such sleep disorders may not only improve quality of life and reduce after-effects, but can also increase life expectancy.

CONCLUSIONS

Sleep disorders are becoming increasingly associated with stroke. In addition to being a risk factor, they can also interfere in the outcome and recovery of stroke patients. This article aims to present an exhaustive and current review on strokes and their relationship with sleep alterations and sleep disorders.