Sleep apnoea and ischaemic stroke: current knowledge and future directions

Clinic and ambulatory blood pressures, blood pressure phenotypes and mortality in patients with a previous stroke

There is scarce evidence of the role of clinic and ambulatory BP indices, as well as blood pressure phenotypes in the prognosis of stroke survivors. We aimed to evaluate the association between ambulatory BP indices and mortality in patients with a previous stroke. Our study was an observational cohort study from individuals included in the Spanish Ambulatory Blood Pressure Registry from March 2004 to December 2014. The Cox model was used to estimate associations between usual clinic and ambulatory BP and mortality, adjusted for confounders and additionally for alternative measures of BP. Two thousand one hundred and eighty-three patients with a previous stroke were included. During a median of 9.2 years, 632 (28.9%) patients died: 236 (10.8%) from cardiovascular causes. In the confounder-adjusted model, clinic systolic BP was not associated with the risk of all-cause or cardiovascular mortality. In contrast, systolic BP indices obtained through ABPM (24 h, day and night) were all associated with all-cause and cardiovascular death. In the simultaneous adjustment of daytime and night-time systolic BP, only night-time systolic BP remained significantly associated with all-cause and cardiovascular death: HR 1.35 (95% CI 01.21-1.51) and 1.44 (1.20-1.72), respectively. For diastolic BP, only night-time BP was associated with all-cause and cardiovascular mortality: HR 1.32 (1.18-1.48) and 1.57 (1.31-1.88), respectively. According to the circadian pattern, a riser pattern was associated with all-cause and cardiovascular mortality: HR 1.49 (1.18-1.87) and 1.70 (1.14-2.52), respectively. In conclusion, in patients who have suffered a stroke, night-time BP is the BP estimate most closely associated with all-cause and cardiovascular mortality.

Trajectories of self-reported daytime sleepiness post-ischemic stroke and transient ischemic attack: A propensity score matching study versus non-stroke patients

INTRODUCTION

Severe sleep apnea (SA) affects one-third of stroke patients. Sleepiness, one of the cardinal symptoms of SA, negatively impacts functional stroke outcomes. The impact of continuous positive airway pressure (CPAP) on post-stroke sleepiness is poorly described. We aimed to compare through a propensity score matching the trajectories of self-reported sleepiness post-stroke with matched individuals including SA patients adherent or not to CPAP.

PATIENTS AND METHODS

Sixty five (80.2%) ischemic stroke and 16 (19.8%) TIA patients (median [Q1;Q3] age = 67.0 [58.0;74.0] years, 70.4% male, body mass index [BMI] = 26.1 [24.5;29.8] kg·m-2, admission NIHSS = 3.0 [1.0;5.0]), with polysomnography and an Epworth Sleepiness Scale (ESS) performed within 1 year following stroke and with a follow-up ESS (delay = 236 [147;399] days) were included in the analysis. A 2:1 propensity score matching based on age, gender, BMI, and the apnea-hypopnea index was performed to identify 162 matched individuals referred for SA suspicion, free of stroke or TIA. Multivariable negative binomial regression models were performed to identify the determinants of sleepiness trajectories post-stroke.

RESULTS

Baseline ESS was comparable between stroke/TIA and matched individuals (median [Q1; Q3] ESS = 7 [4;10] versus 6 [4;10], p = 0.86). The range of improvement in ESS was higher in stroke patients compared to controls (∆ESS = -2 [-4;1] vs -1 [-3;2], p = 0.03). In multivariable analysis, comorbid SA and CPAP treatment did not influence trajectories of sleepiness post-stroke.

DISCUSSION AND CONCLUSION

Sleepiness improvement was unexpectedly higher in stroke patients compared to matched individuals, with no significant influence of comorbid SA and CPAP on its trajectory. Sleepiness may not be primarily indicative of SA in stroke or TIA patients.

Sleep disorders as both risk factors for, and a consequence of, stroke: A narrative review

BACKGROUND AND PURPOSE

Sleep disorders are increasingly implicated as risk factors for stroke, as well as a determinant of stroke outcome. They can also occur secondary to the stroke itself. In this review, we describe the variety of different sleep disorders associated with stroke and analyze their effect on stroke risk and outcome.

METHODS

A search term-based literature review ("sleep," "insomnia," "narcolepsy," "restless legs syndrome," "periodic limb movements during sleep," "excessive daytime sleepiness" AND "stroke" OR "cerebrovascular" in PubMed; "stroke" and "sleep" in ClinicalTrials.gov) was performed. English articles from 1990 to March 2023 were considered.

RESULTS

Increasing evidence suggests that sleep disorders are risk factors for stroke. In addition, sleep disturbance has been reported in half of all stroke sufferers; specifically, an increase is not only sleep-related breathing disorders but also periodic limb movements during sleep, narcolepsy, rapid eye movement (REM) sleep behavior disorder, insomnia, sleep duration, and circadian rhythm sleep-wake disorders. Poststroke sleep disturbance has been associated with worse outcome.

CONCLUSION

Sleep disorders are risk factors for stroke and associated with worse stroke outcome. They are also a common consequence of stroke. Recent guidelines suggest screening for sleep disorders after stroke. It is possible that treatment of sleep disorders could both reduce stroke risk and improve stroke outcome, although further data from clinical trials are required.

To observe the clinical effect of lipoic acid combined with continuous positive airway pressure ventilation in treating obstructive sleep apnea-hypopnea syndrome and its effect on peripheral blood γ-aminobutyric acid and melatonin levels

BACKGROUND

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is a common respiratory disease with potential lethality. At present, the commonly used treatment method is continuous positive airway pressure ventilation, but with the prolongation of the course of the disease, the effect of single ventilation on the improvement of oxidative stress levels is not good. Lipoic acid is a commonly used antioxidant in clinics. In this paper, lipoic acid combined with continuous positive airway pressure ventilation is used to explore whether it has a better therapeutic effect on patients.

AIM

To probe into the clinical efficacy of lipoic acid combined with continuous positive airway pressure ventilation in the therapy of OSAHS.

METHODS

82 patients with OSAHS who were cured in our hospital from March 2021 to September 2022 were prospectively collected as subjects. Based on different treatment methods, patients were grouped into a control group (43 cases) and an observation group (39 cases). The control group was treated with continuous positive airway pressure (CPAP), and the observation group was treated with lipoic acid based on control group. The therapeutic effects were measured by apnea hypopnea index (AHI), oxygen saturation (SpO2), mean oxygen saturation (MSpO2), serum malondialdehyde (MDA), superoxide dismutase (SOD), hypoxia inducible factor-1α (HIF-1α) levels, peripheral blood γ-aminobutyric acid, melatonin levels.

RESULTS

The clinical effectiveness of the observation group was better (P < 0.05). After treatment, AHI, the levels of MDA and HIF-1α in the observation group were lower and SpO2, MSpO2 and the level of SOD, γ- aminobutyric acid, and melatonin were higher than those in the control group (P < 0.05). The levels of γ- aminobutyric acid and melatonin were negatively correlated with the severity of symptoms, ESS, and AIS scores (P < 0.05).

CONCLUSIONS

The clinical effect of lipoic acid combined with CPAP in the treatment of OSAHS is better, and it has a positive effect on the levels of γ-aminobutyric acid and melatonin in peripheral blood. Lipoic acid was added to the original method for treatment, and the therapeutic effect was greatly improved.

Genetic associations between Rapid Eye Movement (REM) sleep behavior disorder and cardiovascular diseases

BACKGROUND

Previous studies revealed that sleep disorders are potential risk factors for cardiovascular diseases, such as obstructive sleep apnea and rapid eye movement (REM) sleep behavior disorder (RBD). However, the causal associations between RBD and cardiovascular diseases remained unknown.

MATERIALS AND METHODS

We used the latest and largest summary-level genome-wide association studies of RBD, stroke and its subtypes, coronary artery disease (CAD), myocardial infarction (MI), and heart failure (HF) to select genetic variants as the instrumental variables. Mendelian randomization (MR) analysis was performed to test the causal associations between RBD and the cardiovascular diseases above. Inverse variance weighted method was used as the main analysis.

RESULTS

After multiple comparisons, genetically predicted RBD was significantly associated with the risk of HF [odds ratio (OR) = 1.033, 95% CI 1.013-1.052, p = 0.001]. Leave-one-out analysis further supported the robustness of the causal association. Furthermore, we identified a suggestive association between genetically predicted MI and RBD (OR = 0.716, 95% CI 0.546-0.940, p = 0.016). However, in our study no associations were identified of RBD with CAD or stroke and its subtypes.

CONCLUSION

Our study highlighted the potential associations between RBD and cardiovascular diseases at genetic level, including HF and MI. More studies were required to clarify the biological mechanisms involved the associations.

Multimodal data integration for enhanced longitudinal prediction for cardiac and cerebrovascular events following initial diagnosis of obstructive sleep apnea syndrome

Background

Obstructive sleep apnea syndrome (OSAS), a prevalent condition, often coexists with intricate metabolic issues and is frequently associated with negative cardiovascular outcomes. We developed a longitudinal prediction model integrating multimodal data for cardiovascular risk stratification of patients with an initial diagnosis of OSAS.

Methods

We reviewed the data of patients with new-onset OSAS who underwent diagnostic polysomnography between 2018-19. Patients were treated using standard treatment regimens according to clinical practice guidelines.

Results

Over a median follow-up of 32 months, 98/729 participants (13.4%) experienced our composite outcome. At a ratio of 7:3, cases were randomly divided into development (n = 510) and validation (n = 219) cohorts. A prediction nomogram was created using six clinical factors - sex, age, diabetes mellitus, history of coronary artery disease, triglyceride-glucose index, and apnea-hypopnea index. The prediction nomogram showed excellent discriminatory power, based on Harrell's C-index values of 0.826 (95% confidence interval (CI) = 0.779-0.873) for the development cohort and 0.877 (95% CI = 0.824-0.93) for the validation cohort. Moreover, comparing the predicted and observed major adverse cardiac and cerebrovascular events in both development and validation cohorts indicated that the prediction nomogram was well-calibrated. Decision curve analysis demonstrated the good clinical applicability of the prediction nomogram.

Conclusions

Our findings demonstrated the construction of an innovative visualisation tool that utilises various types of data to predict poor outcomes in Chinese patients diagnosed with OSAS, providing accurate and personalised therapy.

Registration

Chinese Clinical Trial Registry ChiCTR2300075727.

Association between the triglyceride glucose index and obstructive sleep apnea and its symptoms: results from the NHANES

BACKGROUND

Certain studies have indicated a link between obstructive sleep apnea and insulin resistance in specific populations. To gain more clarity, extensive research involving a broad sample of the overall population is essential. The primary objective of this study was to investigate this correlation by utilizing data from the National Health and Nutrition Examination Survey database.

METHODS

The analysis incorporated data from the National Health and Nutrition Examination Survey database spanning the time periods from 2005 to 2008 and from 2015 to 2018, with a focus on American adults aged 18 years and older after applying weight adjustments. Key variables such as obstructive sleep apnea, triglyceride glucose index, and various confounding factors were considered. A generalized linear logistic regression model was used to investigate the association between obstructive sleep apnea and the triglyceride glucose index, with additional exploration of the consistency of the results through hierarchical analysis and other techniques.

RESULTS

The study included participants aged between 18 and 90 years, with an average age of 46.75 years. Among the total sample, 50.76% were male. The triglyceride glucose index demonstrated a diagnostic capability for obstructive sleep apnea, with an AUC of 0.701 (95% CI: 0.6619-0.688). According to the fully adjusted model, individuals in the fourth quartile of the triglyceride glucose index showed an increased likelihood of having obstructive sleep apnea compared to those in the first quartile (OR: 1.45; 95% CI: 1.02-2.06; P < 0.05). Subgroup analysis indicated that male sex (OR: 2.09; 95% CI: 1.76-2.45; P < 0.05), younger age (OR: 2.83; 95% CI: 2.02-3.96; P < 0.05), white ethnicity (OR: 2.29; 95% CI: 1.93-2.73; P < 0.05), and obesity (OR: 1.54; 95% CI: 1.28-1.85; P < 0.05) were correlated with an elevated risk of OSA.

CONCLUSIONS

This study demonstrated a strong association between an elevated TG index and OSA. Additionally, the triglyceride glucose index could serve as an independent predictor of obstructive sleep apnea.

High Monocyte-to-Lymphocyte Ratio is Associated with Obstructive Sleep Apnea Hypopnea Syndrome

Objective

This study aims to explore the correlation between serum monocyte-to-lymphocyte ratio (MLR) and other inflammatory parameters with the occurrence of obstructive sleep apnea-hypopnea syndrome (OSAHS) in patients.

Methods

This study included 310 patients who underwent polysomnography monitoring at our hospital between January 2021 and January 2023. Routine blood inflammatory parameters and polysomnography (PSG) results were also evaluated. The differences in inflammatory markers between the OSAHS and normal groups were compared, and OSAHS independent related factors were screened.

Results

The MLR of OSAHS group was significantly higher than that of control group, and the difference was statistically significant. Multivariate logistic regression analysis suggested that MLR is an independent risk factor for OSAHS.

Conclusion

High MLR was correlated with OSAHS. The diagnostic value of MLR was better than that of the other inflammatory parameters.

Impact of Comorbid Sleep-Disordered Breathing and Atrial Fibrillation on the Long-Term Outcome After Ischemic Stroke

BACKGROUND

Sleep-disordered breathing (SDB) and atrial fibrillation (AF) are highly prevalent in patients with stroke and are recognized as independent risk factors for stroke. Little is known about the impact of comorbid SDB and AF on long-term outcomes after stroke.

METHODS

In this prospective cohort study, 353 patients with acute ischemic stroke or transient ischemic attacks were analyzed. Patients were screened for SDB by respiratory polygraphy during acute hospitalization. Screening for AF was performed using a 7-day ECG up to 3× in the first 6 months. Follow-up visits were scheduled at 1, 3, 12, 24, and 36 months poststroke. Cox regression models adjusted for various factors (age, sex, body mass index, hypertension, diabetes, dyslipidemia, and heart failure) were used to assess the impact of comorbid SDB and AF on subsequent death or cerebro-cardiovascular events.

RESULTS

Among 353 patients (299 ischemic stroke and 54 transient ischemic attacks), median age, 67 (interquartile range, 57-74) years with 63% males. Moderate-to-severe SDB (apnea-hypopnea index score, ≥15/h) was present in 118 (33.4%) patients. Among the 56 (15.9%) patients with AF, 28 had comorbid moderate-to-severe SDB and AF. Over 36 months, there were 12 deaths and 67 recurrent cerebro-cardiovascular events. Patients with comorbid moderate-to-severe SDB and AF had a higher risk of subsequent death or cerebro-cardiovascular events compared with those with only moderate-to-severe SDB without AF (hazard ratio, 2.49 [95% CI, 1.18-5.24]) and to those without moderate-to-severe SDB or AF (hazard ratio, 2.25 [95% CI, 1.12-4.50]). However, no significant difference was found between the comorbid moderate-to-severe SDB and AF group and the group with only AF without moderate-to-severe SDB (hazard ratio, 1.64 [95% CI, 0.62-4.36]).

CONCLUSIONS

Comorbid moderate-to-severe SDB and AF significantly increase the risk of long-term mortality or recurrent cerebro-cardiovascular events after acute ischemic stroke. Considering both conditions as cumulative and modifiable cerebro-cardiovascular risk factors is of interest for the management of acute stroke.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02559739.

Diphenyl Diselenide Attenuates Mitochondrial Damage During Initial Hypoxia and Enhances Resistance to Recurrent Hypoxia

Hypoxia plays a significant role in the development of various cerebral diseases, many of which are associated with the potential risk of recurrence due to mitochondrial damage. Conventional drug treatments are not always effective for hypoxia-related brain diseases, necessitating the exploration of alternative compounds. In this study, we investigated the potential of diphenyl diselenide [(PhSe)2] to ameliorate locomotor impairments and mitigate brain mitochondrial dysfunction in zebrafish subjected to hypoxia. Additionally, we explored whether these improvements could confer resistance to recurrent hypoxia. Through a screening process, an appropriate dose of (PhSe)2 was determined, and animals exposed to hypoxia received a single intraperitoneal injection of 100 mg/kg of the compound or vehicle. After 1 h from the injection, evaluations were conducted on locomotor deficits, (PhSe)2 content, mitochondrial electron transport system, and mitochondrial viability in the brain. The animals were subsequently exposed to recurrent hypoxia to assess the latency time to hypoxia symptoms. The findings revealed that (PhSe)2 effectively crossed the blood-brain barrier, attenuated locomotor deficits induced by hypoxia, and improved brain mitochondrial respiration by modulating complex III. Furthermore, it enhanced mitochondrial viability in the telencephalon, contributing to greater resistance to recurrent hypoxia. These results demonstrate the beneficial effects of (PhSe)2 on both hypoxia and recurrent hypoxia, with cerebral mitochondria being a critical target of its action. Considering the involvement of brain hypoxia in numerous pathologies, (PhSe)2 should be further tested to determine its effectiveness as a potential treatment for hypoxia-related brain diseases.

Functional recovery after ischemic stroke: Impact of different sleep health parameters

Sleep disturbances after ischaemic stroke include alterations of sleep architecture, obstructive sleep apnea, restless legs syndrome, daytime sleepiness and insomnia. Our aim was to explore their impacts on functional outcomes at month 3 after stroke, and to assess the benefit of continuous positive airway pressure in patients with severe obstructive sleep apnea. Ninety patients with supra-tentorial ischaemic stroke underwent clinical screening for sleep disorders and polysomnography at day 15 ± 4 after stroke in a multisite study. Patients with severe obstructive apnea (apnea-hypopnea index ≥ 30 per hr) were randomized into two groups: continuous positive airway pressure-treated and sham (1:1 ratio). Functional independence was assessed with the Barthel Index at month 3 after stroke in function of apnea-hypopnea index severity and treatment group. Secondary objectives were disability (modified Rankin score) and National Institute of Health Stroke Scale according to apnea-hypopnea index. Sixty-one patients (71.8 years, 42.6% men) completed the study: 51 (83.6%) had obstructive apnea (21.3% severe apnea), 10 (16.7%) daytime sleepiness, 13 (24.1%) insomnia, 3 (5.7%) depression, and 20 (34.5%) restless legs syndrome. Barthel Index, modified Rankin score and Stroke Scale were similar at baseline and 3 months post-stroke in the different obstructive sleep apnea groups. Changes at 3 months in those three scores were similar in continuous positive airway pressure versus sham-continuous positive airway pressure patients. In patients with worse clinical outcomes at month 3, mean nocturnal oxygen saturation was lower whereas there was no association with apnea-hypopnea index. Poorer outcomes at 3 months were also associated with insomnia, restless legs syndrome, depressive symptoms, and decreased total sleep time and rapid eye movement sleep.

The relationship between aerodynamic characteristics of the upper airway and severity of obstructive sleep apnea in adults

OBJECTIVE

To investigate the relationship between aerodynamic characteristics of the upper airway and severity of obstructive sleep apnea (OSA) in adults.

METHODS

Ninety-seven adult OSA patients underwent polysomnography and cone beam computed tomography (CBCT). The anatomical and aerodynamic characteristics were measured based on CBCT images and computational fluid dynamics modelling of the upper airway.

RESULTS

After controlling for patients' gender, age, and body mass index (BMI), the maximum velocity during inspiration (In-Vmax) led to the largest increase in the explanatory power of apnea-hypopnea index (AHI) variation. The In-Vmax was closely correlated with the minimum axial area, and their relationship was represented by an inversely proportional fitted curve.

CONCLUSIONS

The In-Vmax was the most relevant to OSA severity, and it could be used to assist in recognizing severe OSA patients and as a primary variable to evaluate treatment outcomes of OSA. The In-Vmax was closely related to the most constricted area of the upper airway.

Effects of brain-Computer interface combined with mindfulness therapy on rehabilitation of hemiplegic patients with stroke: a randomized controlled trial

Aim

To explore the effects of brain-computer interface training combined with mindfulness therapy on Hemiplegic Patients with Stroke.

Background

The prevention and treatment of stroke still faces great challenges. Maximizing the improvement of patients' ability to perform activities of daily living, limb motor function, and reducing anxiety, depression, and other social and psychological problems to improve patients' overall quality of life is the focus and difficulty of clinical rehabilitation work.

Methods

Patients were recruited from December 2021 to November 2022, and assigned to either the intervention or control group following a simple randomization procedure (computer-generated random numbers). Both groups received conventional rehabilitation treatment, while patients in the intervention group additionally received brain-computer interface training and mindfulness therapy. The continuous treatment duration was 5 days per week for 8 weeks. Limb motor function, activities of daily living, mindfulness attention awareness level, sleep quality, and quality of life of the patients were measured (in T0, T1, and T2). Generalized estimated equation (GEE) were used to evaluate the effects. The trial was registered with the Chinese Clinical Trial Registry (ChiCTR2300070382).

Results

A total of 128 participants were randomized and 64 each were assigned to the intervention and control groups (of these, eight patients were lost to follow-up). At 6 months, compared with the control group, intervention group showed statistically significant improvements in limb motor function, mindful attention awareness, activities of daily living, sleep quality, and quality of life.

Conclusion

Brain-computer interface combined with mindfulness therapy training can improve limb motor function, activities of daily living, mindful attention awareness, sleep quality, and quality of life in hemiplegic patients with stroke.

Impact

This study provides valuable insights into post-stroke care. It may help improve the effect of rehabilitation nursing to improve the comprehensive ability and quality of life of patients after stroke.

Clinical review registration

https://www.chictr.org.cn/, identifier ChiCTR2300070382.

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.

Periodic Limb Movements during Sleep in Acute Stroke: Prevalence, Severity and Impact on Post-Stroke Recovery

BACKGROUND

Periodic Limb Movements during Sleep (PLMS) have been described to be frequently present in stroke patients. We aimed to evaluate the prevalence and severity of PLMS in acute stroke patients and clarify the association between PLMS and coexisting Sleep Disordered Breathing (SDB). Additionally, we focused on identifying variables that could independently predict the presence of PLMS in patients with acute stroke. The potential impact of PLMS on stroke outcome at three months was investigated as well.

METHODS

In this study, we performed overnight polysomnography on consecutive stroke patients within 72 h from symptom onset. Data regarding clinical and imaging characteristics were prospectively collected. National Institute of Health Stroke Scale (NIHSS), modified Rankin Scale (mRS) and Epworth-Sleepiness Scale (ESS) were used to evaluate stroke severity on admission, stroke outcome at three months and history of daytime sleepiness, respectively. We documented PLMS and SDB using standard polysomnography criteria.

RESULTS

We prospectively assessed 126 patients with acute stroke [109 with ischemic and 17 with hemorrhagic stroke, mean age 60 ± 11 years, 68% men, median NIHSS score on admission: 3 (IQR: 2-7)]. The overall rate of PLMS in our cohort was 76%, and the rate of SDB among patients with PLMS was 83%. PLMS detection rates differed significantly (p-value: <0.001) according to SDB, with PLMS prevalence increasing with greater SDB severity. SDB could independently (OR:4.869, 95% CI: 1.884-12.784, p-value: 0.001) predict the presence of PLMS in the acute stroke phase in multivariable analyses adjusting for potential confounders. Moreover, baseline stroke severity (NIHSS-score increase in per-1 point: OR: 0.819, 95% CI: 0.737-0.895, p-value < 0.001) and PLMS (OR:0.099, 95% CI: 0.009-0.482, p-value = 0.015) were significantly associated with the likelihood of excellent functional outcome (mRS-scores: 0-1) at 3 months.

CONCLUSION

The common presence of mostly severe PLMS in patients with acute stroke and their negative effect on stroke outcomes point out the necessity for early PLMS detection and treatment.

Exploring Astrocyte-Mediated Mechanisms in Sleep Disorders and Comorbidity

Astrocytes, the most abundant cells in the brain, are integral to sleep regulation. In the context of a healthy neural environment, these glial cells exert a profound influence on the sleep-wake cycle, modulating both rapid eye movement (REM) and non-REM sleep phases. However, emerging literature underscores perturbations in astrocytic function as potential etiological factors in sleep disorders, either as protopathy or comorbidity. As known, sleep disorders significantly increase the risk of neurodegenerative, cardiovascular, metabolic, or psychiatric diseases. Meanwhile, sleep disorders are commonly screened as comorbidities in various neurodegenerative diseases, epilepsy, and others. Building on existing research that examines the role of astrocytes in sleep disorders, this review aims to elucidate the potential mechanisms by which astrocytes influence sleep regulation and contribute to sleep disorders in the varied settings of brain diseases. The review emphasizes the significance of astrocyte-mediated mechanisms in sleep disorders and their associated comorbidities, highlighting the need for further research.

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.

Liver Transplantation and the Elderly Candidate: Perioperative Considerations

Pioneered by Thomas Starzl in the early 1970s, liver transplant (LT) is nowadays often considered a final intervention and standard of care to cure many forms of acute and chronic end-stage liver diseases. Started in recipients younger than 60 years old, LT indications are now much broader, and at least, one-fifth of the candidates are older than 65 years. Problems associated with ageing and frailty in LT recipients and their impact on the entire perioperative course are discussed according to a modern anesthesiological perspective and the anesthesiologist covering the role of the perioperative (transplant) physician.

Physical activity for obstructive sleep apnea after stroke? A pilot study assessing the contribution of body fluids

PURPOSE

Obstructive sleep apnea (OSA) and physical inactivity are common after stroke. Physical inactivity can lead to/or exacerbate edema following stroke, and the resultant overnight fluid shift may increase the risk of OSA. We aimed to investigate the effect of physical activity on nocturnal rostral fluid shift, sleep pattern, and edematous state of hemiparetic patients.

METHODS

Neck circumference (tape measured) and arms, legs, and trunk fluid volume (bioelectrical impedance spectrum analyzer) were measured before and after 2 polysomnography (PSG) examinations. In the lab, a whole night PSG was performed after the intervention. The intervention consisted of inactivity (lying down and sitting) or activity (standing, performing calf muscle contractions while standing, walking, and climbing stairs) between 13 and 21 h, after the randomization of the participants. With a 7-day interval, participants crossed over to the other group.

RESULTS

From 126 eligible participants, 8 with hemiparetic post-first-ever ischemic stroke at the subacute phase were recruited (age: 53.2 ± 16.2; 6 women). Physical activity reduced AHI from 19 to 13 n°/h and wake after sleep onset from 76.5 to 60.3 min and increased fluid volume of paretic and non-paretic arms and trunk before sleep compared to inactivity.

CONCLUSION

An acute bout of physical activity reduced OSA classification based on AHI (from moderate to mild) and sleep fragmentation. Our results provide preliminary evidence of a possible link between physical activity in patients after stroke as an intervention to counteract OSA severity and improve sleep.

Association between obstructive sleep apnea symptoms and gout in US population, a cross-sectional study

The results of association between Obstructive Sleep Apnea (OSA) and gout are not consistent. Participants aged 20 years or older in the National Health and Nutrition Examination Survey (NHANES) 2007-2008 and 2015-2018 were included. Weighted univariable and multivariable logistic regressions were used to evaluate the association between OSA symptoms and gout. The subgroup and sensitivity analyses were also performed. Among the 15,947 participants in this study, the mean age was 47.8 years old, 48.87% of whom were male, 4891 had OSA symptoms, and 842 had gout. In multivariable logistic regression analyses, OSA symptoms were positively associated with gout in all models. The odds ratio (OR) was 1.315 and 95% confidence interval (CI) was 1.070-1.616 in fully adjusted model 4. In the subgroup analyses, we found a considerable interaction between OSA symptoms and gender with gout (P for interaction = 0.003). In the sensitivity analyses, the association between OSA symptoms and gout remained stable after adjustment for congestive heart failure and diuretics using. OSA symptoms were associated with an increased likelihood of gout. This association could especially be found in female participants.

The impact of sleep quality and its change on the long-term risk of stroke in middle-aged and elderly people: Findings from the English Longitudinal Study of Ageing

OBJECTIVE

This study focused on middle-aged and elderly adults (mean age ≥60 years) in England and aimed to evaluate the impact of sleep quality and change in sleep quality on the long-term risk of stroke.

PATIENTS/METHODS

The current prospective study enrolled 6214 participants without stroke from wave 4 (2008-2009) of the English Longitudinal Study Aging (ELSA) dataset. From the ELSA questionnaires, sleep quality scores were calculated and used to evaluate the sleep quality of each participant. Cox proportional hazards regression models were used to assess the association between sleep status and stroke risk. Restricted cubic spline (RCS) was employed for the relationship between sleep quality score and the risk of stroke.

RESULTS

During the 8-year follow-up, 130 (2.1%) cases of stroke were recorded. Participants with poor baseline sleep quality had a significantly higher long-term risk of stroke compared with those with good sleep quality (hazard ratio [HR] 2.37, 95% confidence intervals [CI] 1.44, 3.91). For the influence of change in sleep quality on stroke risk, worsened sleep quality was associated with a significant increase in the risk of stroke in the good (HR 2.08, 95% CI, 1.02, 4.26) and intermediate sleep quality groups (HR 2.15, 95% CI, 1.16, 3.98). Moreover, improved sleep quality decreased stroke risk among subjects with poor sleep quality (HR 0.31, 95% CI, 0.15, 0.61).

CONCLUSIONS

Poor and worsened sleep quality is associated with an increased risk of stroke. Emphasis should be placed on improving sleep quality in middle-aged and elderly individuals.

Neurologic Disorders in Women and Sleep

Sleep disorders in women remain underrecognized and underdiagnosed mainly because of gender bias in researching and characterizing sleep disorders in women. Symptoms of common sleep disorders are frequently missed in the general female population and are expected to be further overlooked because of overlapping symptoms in women with neurologic disorders. Given the bidirectional relationship with sleep and neurologic disorders, it remains critical to be aware of the presentation and impact of sleep disorders in this patient population. This article reviews available data on sleep disorders in women with neurologic disorders and discusses their distinctive features.

RAFNet: Restricted attention fusion network for sleep apnea detection

Sleep apnea (SA) is a common sleep-related breathing disorder, which would lead to damage of multiple systemic organs or even sudden death. In clinical practice, portable device is an important tool to monitor sleep conditions and detect SA events by using physiological signals. However, SA detection performance is still limited due to physiological signals with time-variability and complexity. In this paper, we focus on SA detection with single lead ECG signals, which can be easily collected by a portable device. Under this context, we propose a restricted attention fusion network called RAFNet for sleep apnea detection. Specifically, RR intervals (RRI) and R-peak amplitudes (Rpeak) are generated from ECG signals and divided into one-minute-long segments. To alleviate the problem of insufficient feature information of the target segment, we combine the target segment with two pre- and post-adjacent segments in sequence, (i.e. a five-minute-long segment), as the input. Meanwhile, by leveraging the target segment as the query vector, we propose a new restricted attention mechanism with cascaded morphological and temporal attentions, which can effectively learn the feature information and depress redundant feature information from the adjacent segments with adaptive assigning weight importance. To further improve the SA detection performance, the target and adjacent segment features are fused together with the channel-wise stacking scheme. Experiment results on the public Apnea-ECG dataset and the real clinical FAH-ECG dataset with sleep apnea annotations show that the RAFNet greatly improves SA detection performance and achieves competitive results, which are superior to those achieved by the state-of-the-art baselines.

Association of Obstructive Sleep Apnea and Atrial Fibrillation in Acute Ischemic Stroke: A Cross-Sectional Study

Background: There is a growing body of evidence suggesting a link between obstructive sleep apnea (OSA) and atrial fibrillation (AF). The primary objective of this study is to evaluate the association between OSA and AF in acute ischemic stroke. The secondary objective is to describe the clinical features of patients with acute ischemic stroke and concomitant OSA. Methods: We enrolled consecutive patients with acute ischemic stroke. All patients underwent full-night cardiorespiratory polygraphy. To determine if there is an association between AF and OSA, we compared the observed frequency of this association with the expected frequency from a random co-occurrence of the two conditions. Subsequently, patients with and without OSA were compared. Results: A total of 174 patients were enrolled (mean age 67.3 ± 11.6 years; 95 males). OSA and AF were present in 89 and 55 patients, respectively. The association OSA + AF was observed in 33/174 cases, which was not statistically different compared to the expected co-occurrence of the two conditions. Patients with OSA showed a higher neck circumference and body mass index, a higher prevalence of hypertension and dysphagia, and a higher number of central apneas/hypoapneas. In the multivariate analysis, dysphagia and hypertension were independent predictors of OSA. A positive correlation was observed between OSA severity, BMI, and neck circumference. The number of central apneas/hypoapneas was positively correlated with stroke severity. Conclusions: Our data suggest that OSA and AF are highly prevalent but not associated in acute stroke. Our findings support the hypothesis that OSA acts as an independent risk factor for stroke.

Sleep-Disordered Breathing in Acute Stroke: A Single-Center, Prospective, Longitudinal Study

BACKGROUND

Sleep-disordered breathing (SDB) is common among acute stroke patients. We sought to investigate the prevalence, severity and type of SDB in consecutive acute stroke patients. Moreover, we aimed to identify independent predictors of SDB in the acute stroke setting and investigate potential associations between SDB and functional outcomes at three months.

METHODS

We prospectively studied consecutive acute stroke patients, who underwent overnight polysomnography within 72 h from symptom onset. Demographics, clinical and imaging characteristics were documented. Daytime sleepiness preceding the stroke, stroke severity on admission and functional outcome at three months were evaluated using the Epworth-Sleepiness Scale (ESS), National Institute of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS), respectively. SDB was documented using standard polysomnography criteria.

RESULTS

A total of 130 consecutive acute stroke patients were prospectively evaluated [110 with ischemic stroke and 20 with intracerebral hemorrhage, mean age 60.5 ± 10.9 years, 77% men, median NIHSS score on admission: 3 (IQR: 2-17)]. The rate of SDB detection on polysomnography recordings was 79% (95% CI: 71-86). Three variables were independently associated with the likelihood of SDB detection in multivariable analyses adjusting for potential confounders: age (OR per 10-year-increase: 2.318, 95% CI: 1.327-4.391, p = 0.005), male sex (OR: 7.901, 95% CI: 2.349-30.855, p = 0.001) and abnormal ESS-score (OR: 6.064, 95% CI: 1.560-32.283, p = 0.017). Among patients with SDB, congestive heart failure was independently associated with the likelihood of central apnea detection (OR: 18.295, 95% CI: 4.464-19.105, p < 0.001). Among all patients, increasing NIHSS score on admission (OR: 0.817, 95% CI: 0.737-0.891, p < 0.001) and Apnea-Hypopnea Index (OR: 0.979, 95% CI: 0.962-0.996, p = 0.020) emerged as independent predictors of excellent functional outcome at 3 months (mRS-scores 0-1).

CONCLUSION

The high prevalence and severity of SDB in acute stroke patients and its negative impact on functional outcome indicate the importance of polysomnography implementation in everyday clinical practice of acute stroke work-up and management.

Effects of severe obstructive sleep apnea on functional prognosis in the acute phase of ischemic stroke and quantitative electroencephalographic markers

OBJECTIVE

To investigate the effect of severe obstructive sleep apnea (OSA) on functional prognosis in the acute phase and quantitative electroencephalography (EEG) markers during sleep in ischemic stroke patients.

METHODS

This study included 125 mild-to-moderate acute ischemic stroke patients with OSA who underwent polysomnography (PSG) within one week of stroke onset between January 2015 and June 2020. Patients were grouped according to their apnea-hypopnea index (</≥ 30/h). Poor functional prognosis was defined as modified Rankin Scale score ≥3. The EEG recorded by PSG was extracted during different sleep stages for power spectrum analysis. The delta/alpha power ratio (DAR), (delta + theta)/(alpha + beta) ratio (the slowing ratio, TSR), and the relative power (RP) of each frequency band were calculated. Differences in clinical, PSG, and quantitative EEG characteristics were compared between the groups. Additionally, we explored predictors of poor functional prognosis.

RESULTS

Patients with severe OSA had a higher proportion of hypertension, lower relative power of high-frequency bands, and higher delta RP, TSR, and DAR (p < 0.05). Severe OSA was associated with a 3.6-fold increase in risk of poor prognosis (p < 0.05). Increased delta RP and TSR, as well as decreased alpha, beta, and sigma RP, may be independent predictors of a poor functional prognosis.

CONCLUSIONS

Severe OSA is an independent risk factor for a poor functional prognosis in patients with acute ischemic stroke, and quantitative EEG during sleep showed a significant slow wave enhancement, suggesting more severe brain dysfunction. The treatment of severe OSA may improve functional prognosis.

L-Citrulline Supplementation Reduces Blood Pressure and Myocardial Infarct Size under Chronic Intermittent Hypoxia, a Major Feature of Sleep Apnea Syndrome

Intermittent hypoxia (IH) is a landmark of obstructive sleep apnea (OSA) at the core of the cardiovascular consequences of OSA. IH triggers oxidative stress, a major underlying mechanism for elevated blood pressure (BP) and increased infarct size. L-citrulline is an amino acid that has been demonstrated to be protective of the cardiovascular system and exert pleiotropic effects. Therefore, we tested the impact of citrulline supplementation on IH-induced increase in BP and infarct size. Four groups of rats exposed to normoxia (N) or IH [14 days (d), 8 h/day, 30 s-O₂ 21%/30 s-O₂ 5%] and were supplemented or not with citrulline (1 g·kg^-1·d^-1). After 14 d, BP was measured, and hearts were submitted to global ischemia-reperfusion to measure infarct size. Histological and biochemical analyses were conducted on hearts and aorta to assess oxidative stress. Citrulline significantly reduced BP (-9.92%) and infarct size (-18.22%) under IH only. In the aorta, citrulline supplementation significantly decreased superoxide anion and nitrotyrosine levels under IH and abolished the IH-induced decrease in nitrite. Citrulline supplementation significantly decreased myocardial superoxide anion levels and xanthine oxidase enzyme activity under IH. Citrulline shows a cardioprotective capacity by limiting IH-induced pro-oxidant activity. Our results suggest that citrulline might represent a new pharmacological strategy in OSA patients with high cardiovascular risk.

Understanding and approaching excessive daytime sleepiness

Excessive daytime sleepiness (EDS) is a public health issue. However, it remains largely undervalued, scarcely diagnosed, and poorly supported. Variations in the definition of EDS and limitations in clinical assessment lead to difficulties in its epidemiological study, but the relevance of this symptom from a socioeconomic perspective is inarguable. EDS might be a consequence of several behavioural issues leading to insufficient or disrupted sleep, as well as a consequence of sleep disorders including sleep apnoea syndrome, circadian disorders, central hypersomnolence disorders (narcolepsy and idiopathic hypersomnia), other medical or psychiatric conditions, or medications. Furthermore, EDS can have implications for health as it is thought to act as a risk factor for other conditions, such as cardiovascular and neurodegenerative disorders. Because of the heterogeneous causes of EDS and the complexity of its pathophysiology, management will largely depend on the cause, with the final aim of making treatment specific to the individual using precision medicine and personalised medicine.

Proteomic Biomarkers of the Apnea Hypopnea Index and Obstructive Sleep Apnea: Insights into the Pathophysiology of Presence, Severity, and Treatment Response

Obstructive sleep apnea (OSA), a disease associated with excessive sleepiness and increased cardiovascular risk, affects an estimated 1 billion people worldwide. The present study examined proteomic biomarkers indicative of presence, severity, and treatment response in OSA. Participants (n = 1391) of the Stanford Technology Analytics and Genomics in Sleep study had blood collected and completed an overnight polysomnography for scoring the apnea−hypopnea index (AHI). A highly multiplexed aptamer-based array (SomaScan) was used to quantify 5000 proteins in all plasma samples. Two separate intervention-based cohorts with sleep apnea (n = 41) provided samples pre- and post-continuous/positive airway pressure (CPAP/PAP). Multivariate analyses identified 84 proteins (47 positively, 37 negatively) associated with AHI after correction for multiple testing. Of the top 15 features from a machine learning classifier for AHI ≥ 15 vs. AHI < 15 (Area Under the Curve (AUC) = 0.74), 8 were significant markers of both AHI and OSA from multivariate analyses. Exploration of pre- and post-intervention analysis identified 5 of the 84 proteins to be significantly decreased following CPAP/PAP treatment, with pathways involving endothelial function, blood coagulation, and inflammatory response. The present study identified PAI-1, tPA, and sE-Selectin as key biomarkers and suggests that endothelial dysfunction and increased coagulopathy are important consequences of OSA, which may explain the association with cardiovascular disease and stroke.

Heart Failure with Preserved Ejection Fraction and Obstructive Sleep Apnea: A Novel Paradigm for Additional Cardiovascular Benefit of SGLT2 Inhibitors in Subjects With or Without Type 2 Diabetes

After examining the complex interplay between heart failure (HF) in its various clinical forms, metabolic disorders like nonalcoholic fatty liver disease (NAFLD), and obstructive sleep apnea (OSA) syndrome, in this mini-review we described possible favorable effects of sodium-glucose cotransporter 2 inhibitors (SGLT2is) on HF with preserved (i.e., ≥ 50%) ejection fraction (HFpEF) through enhanced cardiorenal function and visceral-subcutaneous body fat redistribution. In greater detail, on the basis of pathophysiological mechanisms underlying OSA onset and the direct positive SGLT2i effect on renal function benefiting chronic kidney disease, we emphasized the promising role of SGLT2is in prevention, rehabilitation, and treatment of patients with OSA regardless of coexisting type 2 diabetes (T2DM). Indeed, SGLT2is enhance lipolysis and fatty acid beta-oxidation. These phenomena might prevent OSA by reducing the size of visceral and subcutaneous adipose tissue and, as proven in humans and animals with T2DM, counteract NAFLD onset and progression. The aforementioned mechanisms may represent an additional SGLT2i cardioprotective effect in terms of HFpEF prevention in patients with OSA, whose NAFLD prevalence is estimated to be over 50%.

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.