Longitudinal Assessment of Sleep Apnea in the Year After Stroke in a Population-Based Study

BACKGROUND

The aim of this study was to characterize change in sleep-disordered breathing severity in the year following stroke, overall, and by ethnicity, within the population-based Brain Attack Surveillance in Corpus Christi Project.

METHODS

First-ever ischemic strokes (n=414) were ascertained by active and passive surveillance and validated by stroke-trained physicians. Patients with stroke were invited to participate in portable sleep apnea testing (ApneaLink Plus) at baseline and 3, 6, and 12 months poststroke. Sleep-disordered breathing severity was assessed by the respiratory event index (apneas and hypopneas/hour of recording). The component obstructive apnea index and central apnea index were also assessed. Time and ethnicity effects on outcomes, as well as ethnic differences in time effects, were analyzed using generalized estimating equations with multivariable adjustment for confounding factors.

RESULTS

Mean age (n=414) was 63.9 years (SD=10.9); 68.4% were Mexican American. Baseline mean respiratory event index, obstructive apnea index, and central apnea index were 21.3 (SD=16.6), 8.6 (SD=11.5), and 1.5 (SD=3.2), respectively. There was no time effect on respiratory event index (P=0.35) but obstructive apnea index increased over time (P<0.01). Averaged over follow-up, respiratory event index and obstructive apnea index were significantly higher in Mexican American than non-Hispanic White persons. No ethnic difference in the time effect was found for either outcome. For central apnea index, there was an ethnicity-time interaction (P=0.01) such that central apnea index increased in non-Hispanic White but did not change in Mexican American persons.

CONCLUSIONS

Sleep-disordered breathing severity was significant and stable for most individuals in the year after stroke. These results do not confirm previous reports of diminishing sleep-disordered breathing severity over time after stroke and would support early assessment and treatment where indicated.

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-disordered breathing and ventilatory chemosensitivity in first ischaemic stroke patients: a prospective cohort study

RATIONALE

Sleep-disordered breathing (SDB) is highly prevalent after stroke. The clinical and ventilatory chemosensitivity characteristics of SDB, namely obstructive, central and coexisting obstructive and central sleep apnoea (coexisting sleep apnoea) following stroke are poorly described.

OBJECTIVE

To determine the respective clinical and ventilatory chemosensitivity characteristics of SDB at least 3 months after a first ischaemic stroke.

METHODS

Cross-sectional analysis of a prospective, monocentric cohort conducted in a university hospital. 380 consecutive stroke or transient ischaemic attack patients were screened between December 2016 and December 2019.

MEASUREMENTS AND MAIN RESULTS

Full-night polysomnography, and hypercapnic ventilatory response were performed at a median (Q1; Q3) time from stroke onset of 134.5 (97.0; 227.3) days. 185 first-time stroke patients were included in the analysis. 94 (50.8%) patients presented no or mild SDB (Apnoea-Hypopnoea Index <15 events/hour of sleep) and 91 (49.2%) moderate to severe SDB, of which 52 (57.1%) presented obstructive sleep apnoea and 39 (42.9%) coexisting or central sleep apnoea. Obstructive sleep apnoea patients significantly differed regarding their clinical presentation from patients with no or mild SDB, whereas there was no difference with coexisting and central sleep apnoea patients. The latter presented a higher frequency of cerebellar lesions along with a heightened hypercapnic ventilatory response compared with no or mild SDB patients.

CONCLUSION

SDB in first-time stroke patients differ in their presentation by their respective clinical traits and ventilatory chemosensitivity characteristics. The heightened hypercapnic ventilatory response in coexisting and central sleep apnoea stroke patients may orientate them to specific ventilatory support.

Sleep-wake disturbances in supra-and infratentorial stroke: an analysis of post-acute sleep architecture and apnea

BACKGROUND AND PURPOSE

Sleep-wake disturbances (SWD) are common following stroke, and often extend into the post-acute to chronic periods of recovery. Of particular interest to recovery is a reduction in rapid eye movement (REM) sleep, as we know REM sleep to be important for learning and memory. While there is a breadth of evidence linking SWD and stroke, much less work has been done to identify and determine if differences in sleep architecture and apnea severity are dependent on stroke infarct topographies.

METHODS

A retrospective chart review was conducted of 48 ischemic stroke patients having underwent a full, overnight polysomnography (PSG). All patients were over 30 days post-injury (post-acute) at the time of the PSG. Patients were divided into supra- and infratentorial infarct topography groups based on available medical and imaging records. In addition to sleep study record review, cognitive and outcome measures were examined.

RESULTS

Results showed that patients with infratentorial stroke had poorer sleep efficiency, decreased REM sleep, and higher apnea hypopnea index (AHI) than those with supratentorial injuries. Longer continuous REM periods were correlated with higher verbal learning/memory scores, higher levels of positive affect, and lower levels of emotional/behavioral dyscontrol. Neither age nor AHI were significantly correlated with the amount or duration of REM. Slow-wave sleep was significantly reduced across both injury topographies.

CONCLUSIONS

Infratentorial ischemic stroke patients display significant disruptions in sleep architecture and may require close monitoring for SWDs in the post-acute period to maximize outcome potential. REM sleep is particularly affected when compared to supratentorial ischemic stroke.

Prevalence and Determinants of Sleep Apnea in Patients with Stroke: A Meta-Analysis

OBJECTIVES

Recent meta-analyses have noted that ∼70% of transient ischemic attack (TIA)/stroke patients have sleep apnea. However, the heterogeneity between studies was high and did not appear to be accounted by the phase of stroke. We conducted an updated meta-analysis and aimed to determine whether the prevalence of sleep apnea amongst stroke patients differs by the subtype, etiology, severity and location of stroke and hence could account for some of the unexplained heterogeneity observed in previous studies.

MATERIALS AND METHODS

We searched Medline, Embase, CINAHL and Cochrane Library (from their commencements to July 2020) for studies which reported the prevalence of sleep apnea by using polysomnography in TIA/stroke patients. We used random-effects model to calculate the pooled prevalence of sleep apnea and explored whether the prevalence differed by stroke characteristics.

RESULTS

Seventy-five studies describing 8670 stroke patients were included in this meta-analysis. The overall prevalence of sleep apnea was numerically higher in patients with hemorrhagic vs. ischemic stroke [82.7% (64.4-92.7%) vs. 67.5% (63.2-71.5%), p=0.098], supratentorial vs. infratentorial stroke [64.4% (56.7-71.4%) vs. 56.5% (42.2-60.0%), p=0.171], and cardioembolic [74.3% (59.6-85.0%)] vs. other ischemic stroke subtypes [large artery atherosclerosis: 68.3% (52.5-80.7%), small vessel occlusion: 56.1% (38.2-72.6%), others/undetermined: 47.9% (31.6-64.6%), p=0.089]. The heterogeneity in sleep apnea prevalence was partially accounted by the subtype (1.9%), phase (5.0%) and location of stroke (14.0%) among reported studies.

CONCLUSIONS

The prevalence of sleep apnea in the stroke population appears to differ by the subtype, location, etiology and phase of stroke.

Sleep-disordered breathing and cerebral small vessel disease-acute and 6 months after ischemic stroke

PURPOSE

Sleep-disordered breathing (SDB) occurs frequently after stroke and is associated with poor functional outcome and increased mortality. The purpose of this study was to detect changes in SDB over time after acute ischemic stroke and investigate relationships between SDB and stroke etiologies with focus on cerebral small vessel disease.

METHODS

From May 2015 to August 2016, we conducted an observational study of 99 patients with mild to moderate stroke (median age: 68 years, range 36-88; 56% men). Polysomnography was performed within 7 days of stroke onset (n = 91) and after 6 months (n = 52). The strokes were classified using the etiological TOAST classification. Total small vessel disease (SVD) scores were calculated based on MRIs.

RESULTS

SDB, defined as an apnea-hypopnea index (AHI) ≥ 15, was found in 56% of patients in the acute state and in 44% at follow-up. AHI decreased over time (median change 4.7, 95% confidence interval [95% CI] 0.5-8.9; p = 0.03). Patients with AHI ≥ 15 in both the acute state and at follow-up had higher SVD score at follow-up (p = 0.003). AHI was not associated with ischemic stroke subgroups according to the TOAST classification.

DISCUSSION

In conclusion, 6 months after stroke, AHI decreased, but 44% still had AHI ≥ 15. Persistent SDB in both the acute state and at follow-up was associated with a higher SVD score, but not to the TOAST subgroups. SDB evaluation should be offered to stroke patients, and the effect of SDB on cerebral small vessel disease needs to be further investigated using the well-defined SVD score.

TRIAL REGISTRATION

clinicaltrials.gov NCT02111408, April 11, 2014.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Acute stroke and TIA patients have specific polygraphic features of obstructive sleep apnea

Purpose

Obstructive sleep apnea (OSA) is associated with increased risk for stroke, which is known to further impair respiratory functions. However, it is unknown whether the type and severity of respiratory events are linked to stroke or transient ischemic attack (TIA). Thus, we investigate whether the characteristics of individual respiratory events differ between patients experiencing TIA or acute ischemic stroke and matched patients with clinically suspected sleep-disordered breathing.

Methods

Polygraphic data of 77 in-patients with acute ischemic stroke (n = 49) or TIA (n = 28) were compared to age, gender, and BMI-matched patients with suspected sleep-disordered breathing and no cerebrovascular disease. Along with conventional diagnostic parameters (e.g., apnea-hypopnea index), durations and severities of individual apneas, hypopneas and desaturations were compared between the groups separately for ischemic stroke and TIA patients.

Results

Stroke and TIA patients had significantly shorter apneas and hypopneas (p < 0.001) compared to matched reference patients. Furthermore, stroke patients had more central apnea events (p = 0.007) and a trend for higher apnea/hypopnea number ratios (p = 0.091). The prevalence of OSA (apnea-hypopnea index ≥ 5) was 90% in acute stroke patients and 79% in transient ischemic attack patients.

Conclusion

Stroke patients had different characteristics of respiratory events, i.e., their polygraphic phenotype of OSA differs compared to matched reference patients. The observed differences in polygraphic features might indicate that stroke and TIA patients suffer from OSA phenotype recently associated with increased cardiovascular mortality. Therefore, optimal diagnostics and treatment require routine OSA screening in patients with acute cerebrovascular disease, even without previous suspicion of OSA.

Electronic supplementary material

The online version of this article (10.1007/s11325-019-02010-2) contains supplementary material, which is available to authorized users.

Severely Disturbed Sleep in Patients With Acute Ischemic Stroke on Stroke Units: A Pilot Study

Introduction: Previous studies revealed a high prevalence of sleep-wake disturbances in subacute and chronic stroke. We analyzed sleep quantity and quality in patients with hyperacute ischemic stroke on stroke units.

Methods: We categorized sleep stages as N1, N2, N3, and REM according to the 2017 criteria of the American Academy of Sleep Medicine in 23 continuous, overnight EEG registrations from 18 patients, starting within 48 h since the onset of cortical ischemic stroke. Associations between presence and duration of sleep stages, and secondary deterioration or functional outcome were analyzed.

Results: Physiological sleep cycles were seen in none of the patients. Otherwise, sleep stages alternated chaotically, both during day- and during nighttime, with a sleep efficiency of 30% and 10.5 ± 4.4 (mean ± SD) awakenings per hour of sleep. We cannot differentiate between stroke related and external factors. Only few interruptions could be related to planned nightly wake up calls, but turbulence on stroke units may have played a role. Six patients (seven nights) did not reach deep sleep (N3), 10 patients (13 nights) did not reach REM sleep. If reached, the mean durations of deep and REM sleep were short, with 37 (standard deviation (SD) 25) and 18 (SD15) minutes, respectively. Patients with secondary deterioration more often lacked deep sleep (N3) than patients without secondary deterioration [4 (57%) vs. 2 (25%)], but without statistical significance (p = 0.12).

Conclusion: We show that sleep is severely disturbed in patients with acute ischemic stroke admitted to stroke units. Larger studies are needed to clarify associations between deprivation of deep sleep and secondary deterioration.

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.

Role of sleep-disordered breathing and sleep-wake disturbances for stroke and stroke recovery

Background:

Sleep-disordered breathing (SDB) and sleep-wake disturbances (SWD) are highly prevalent in stroke patients. Recent studies suggest that they represent both a risk factor and a consequence of stroke and affect stroke recovery, outcome, and recurrence.

Methods:

Review of literature.

Results:

Several studies have proven SDB to represent an independent risk factor for stroke. Sleep studies in TIA and stroke patients are recommended in view of the very high prevalence (>50%) of SDB (Class IIb, level of evidence B). Treatment of obstructive SDB with continuous positive airway pressure is recommended given the strength of the increasing evidence in support of a positive effect on outcome (Class IIb, level of evidence B). Oxygen, biphasic positive airway pressure, and adaptive servoventilation may be considered in patients with central SDB. Recently, both reduced and increased sleep duration, as well as hypersomnia, insomnia, and restless legs syndrome (RLS), were also suggested to increase stroke risk. Mainly experimental studies found that SWD may in addition impair neuroplasticity processes and functional stroke recovery. Treatment of SWD with hypnotics and sedative antidepressants (insomnia), activating antidepressants or stimulants (hypersomnia), dopaminergic drugs (RLS), and clonazepam (parasomnias) are based on single case observations and should be used with caution.

Conclusions:

SDB and SWD increase the risk of stroke in the general population and affect short- and long-term stroke recovery and outcome. Current knowledge supports the systematic implementation of clinical procedures for the diagnosis and treatment of poststroke SDB and SWD on stroke units.