Cardiovascular risk in patients with sleep apnoea with or without continuous positive airway pressure therapy: follow-up of 4.5 million Danish adults

Sleep apnea, the risk of out-of-hospital cardiac arrest, and potential benefits of continuous positive airway pressure therapy: A nationwide study

OBJECTIVE

Patients with sleep apnea (SA) are at increased cardiovascular risk. However, little is known about the risk of out-of-hospital cardiac arrest (OHCA) in patients with SA. Therefore, we studied the relation between SA patients who did and did not receive continuous positive airway pressure (CPAP) therapy with OHCA in the general population.

METHODS

Using nationwide databases, we conducted a nested case-control study with OHCA-cases of presumed cardiac causes and age/sex/OHCA-date matched non-OHCA-controls from the general population. Conditional logistic regression models with adjustments for well-known OHCA risk factors were performed to generate odds ratio (OR) of OHCA comparing patients with SA receiving and not receiving CPAP therapy with individuals without SA.

RESULTS

We identified 46,578 OHCA-cases and 232,890 matched non-OHCA-controls [mean: 71 years, 68.8% men]. Compared to subjects without SA, having SA without CPAP therapy was associated with increased odds of OHCA after controlling for relevant confounders (OR:1.20, 95%-Cl:1.06-1.36), while having SA with CPAP therapy was not associated with OHCA (OR:1.04, 95%-Cl:0.93-1.36). Regardless of CPAP therapy, age and sex did not significantly influence our findings. Our findings were confirmed in: (I) patients with neither ischemic heart disease nor heart failure (untreated SA, OR:1.24, 95%-CI:1.04-1.47; SA with CPAP, OR:1.08, 95%-CI:0.93-1.25); and (II) in patients without cardiovascular disease (untreated SA, OR:1.33, 95%-CI:1.07-1.65; SA with CPAP, OR:1.14, 95%-CI:0.94-1.39).

CONCLUSION

SA not treated with CPAP was associated with OHCA, while no increased risk of OHCA was found for SA patients treated with CPAP.

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

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

Clinical significance of obstructive sleep apnea in patients with acute coronary syndrome with or without prior stroke: a prospective cohort study

BACKGROUND AND OBJECTIVE

Whether obstructive sleep apnea (OSA) is associated with worse prognosis in patients with acute coronary syndrome (ACS) with or without prior stroke remains unclear. We investigated the association of OSA with cardiovascular events in ACS patients with or without prior stroke.

METHODS

Between June 2015 and January 2020, we prospectively recruited eligible ACS patients who underwent cardiorespiratory polygraphy during hospitalization. We defined OSA as an apnea hypopnea index (AHI) ≥ 15 events/hour. The primary composite end point was major adverse cardiovascular and cerebrovascular events (MACCEs), including cardiovascular death, myocardial infarction, stroke, ischemia-driven revascularization, or hospitalization for unstable angina or heart failure.

RESULTS

Among 1927 patients enrolled, 207 patients had prior stroke (10.7%) and 1014 had OSA (52.6%). After a mean follow-up of 2.9 years, patients with stroke had significantly higher risk of MACCEs than those without stroke (hazard ratio [HR]:1.49; 95% confidence interval [CI]: 1.12-1.98, P = 0.007). The multivariate analysis showed that patients with OSA had 2.0 times the risk of MACCEs in prior stroke group (41 events [33.9%] vs 18 events [20.9%]; HR:2.04, 95% CI:1.13-3.69, P = 0.018), but not in non-prior stroke group (186 events [20.8%] vs 144 events [17.4]; HR:1.21, 95% CI 0.96-1.52, P = 0.10). No significant interaction was noted between prior stroke and OSA for MACCE (interaction P = 0.17).

CONCLUSIONS

Among ACS patients, the presence of OSA was associated with an increased risk of cardiovascular events in patients with prior stroke. Further trials exploring the efficacy of OSA treatment in high-risk patients with ACS and prior stroke are warranted. Trial registration Clinicaltrials.gov identifier NCT03362385.

Comparative study of a wearable intelligent sleep monitor and polysomnography monitor for the diagnosis of obstructive sleep apnea

PURPOSE

Due to the lack of an objective population-based screening tool for obstructive sleep apnea (OSA), a large number of patients with potential OSA have not been identified in the general population. Our study compared an objective wearable sleep monitoring device with polysomnography (PSG) to provide a reference for OSA screening in a large population.

METHODS

Using a self-control method, patients admitted to our sleep center from July 2020 to March 2021 were selected for overnight PSG and wearable intelligent sleep monitor (WISM) at the same time. The sensitivity and specificity of the device for the diagnosis of OSA were evaluated.

RESULTS

A total of 196 participants (mean age: 45.1 ± 12.3 years [18-80 years]; 168 men [86%]) completed both PSG and WISM monitoring. Using an apnea-hypopnea index (AHI) ≥ 5 events/h as the diagnostic criterion, the sensitivity, specificity, kappa value, and area under the receiver operating characteristic curve of the WISM for OSA diagnosis were 93%, 77%, 0.6, and 0.95, respectively. Using an AHI ≥ 15 events/h as the diagnostic criterion for moderate-to-severe OSA, these values were 92%, 89%, 0.8, and 0.95, respectively. The mean difference in the AHI between PSG and the artificial intelligence oxygen desaturation index from the WISM was 6.8 events/h (95% confidence interval: - 13.1 to 26.7).

CONCLUSION

Compared with the PSG, WISM exhibits good sensitivity and specificity for the diagnosis of OSA. This small, simple, and easy-to-use device is more suitable for OSA screening in a large population because of its single-step application procedure.

Prevalence of silent atrial fibrillation and cardiovascular disease in patients with obstructive sleep apnea

OBJECTIVE

Patients with silent and undiagnosed atrial fibrillation (AF) have increased risk of ischemic stroke. Patients with obstructive sleep apnea (OSA) have an increased risk of both AF and ischemic stroke. Our aim was to investigate the prevalence of silent AF and associated risk factors in patients investigated for OSA or with known OSA.

METHODS

This prospective observational study was performed in two sites; one outpatient sleep-clinic at Zealand University Hospital and one private Ear-Nose- and Throat clinic. Patients were investigated with a type-3 portable sleep-monitoring device, while heart rhythm was home-monitored for 7 days with an event-triggered loop recorder. Patients were stratified in groups of mild, moderate and severe OSA based on Apnea-Hypopnea-Index (AHI).

RESULTS

In a cohort of 303 patients, 238 (78.5%) were diagnosed with moderate/or severe OSA and 65 (21.5%) with no/mild OSA who constituted the control group. In 238 patients with moderate and severe OSA, AF was detected in 21 patients (8.8%) vs. 1 patient (1.5%,[p=0.045]) with mild OSA. Candidates for anticoagulation therapy were referred for further cardiovascular treatment. The majority of patients had known hypertension (n = 200,66%) and dyslipidemia (n = 235,[77.6%]) In patients with moderate/or severe OSA (AHI≥15), hypertension was more dysregulated (p=0.005) and more patients suffered from unknown prediabetes (n = 36, 3.1% vs. 14.3%[p<0.001]).

CONCLUSION

Undiagnosed AF and undertreated cardiovascular modifiable risk factors are common in a cohort of patients with OSA. With this study we propose that long-period home-monitoring in these patients is useful for identifying candidates for preventive anticoagulation, cardiovascular treatment and possibly prevent future ischemic stroke.

Abnormal Cerebral Blood Flow and Volumetric Brain Morphometry in Patients With Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a serious breathing disorder, leading to myocardial infarction, high blood pressure, and stroke. Brain morphological changes have been widely reported in patients with OSA. The pathophysiological mechanisms of cerebral blood flow (CBF) changes associated with OSA are not clear. In this study, 20 patients with OSA and 36 healthy controls (HCs) were recruited, and then pseudo-continuous arterial spin labeling (pCASL) and voxel-based morphometry (VBM) methods were utilized to explore blood perfusion and morphological changes in the patients with OSA. Compared with the HC group, the OSA group showed increased CBF values in the right medial prefrontal cortex (mPFC), left precentral gyrus, and right insula and showed decreased CBF values in the right temporal pole (TP) and the right cerebellum_Crus2. Compared with the HC group, the patients with OSA showed decreased gray matter volume (GMV) in the right dorsal lateral prefrontal cortex (DLPFC), the right occipital pole, and the vermis. There were no significantly increased GMV brain regions found in patients with OSA. Pearson correlation analysis showed that the reduced GMV in the right DLPFC and the right occipital pole was both positively correlated with Mini-Mental State Examination (MMSE) (r = 0.755, p < 0.001; r = 0.686, p = 0.002) and Montreal Cognitive Assessment (MoCA) scores (r = 0.716, p = 0.001; r = 0.601, p = 0.008), and the reduced GMV in the right occipital pole was negatively correlated with duration of illness (r = -0.497, p = 0.036). Patients with OSA have abnormal blood perfusion metabolism and morphological changes in brain regions including the frontal lobe and the cerebellum and were closely related to abnormal behavior, psychology, and cognitive function, which play an important role in the pathophysiological mechanism of OSA.

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.

Effects of Hydroxychloroquine on endOthelial function in eLDerly with sleep apnea (HOLD): study protocol for a randomized clinical trial

BACKGROUND

Sleep apnea and coronary artery disease are prevalent and relevant diseases. The mechanism by which sleep apnea leads to coronary artery disease remains unclear. Intermittent hypoxia, caused by sleep apnea, leads to inflammation and consequent endothelial dysfunction. Endothelial dysfunction precedes the development of atherosclerotic disease and the occurrence of cardiovascular events. Agents that potentially act to improve endothelial function can help prevent cardiovascular events. Patients using immunomodulators due to rheumatic diseases have a lower prevalence of cardiovascular diseases. However, the potential cardioprotective effect of these drugs in patients without autoimmune diseases is not clear. Hydroxychloroquine (HCQ) is an immunomodulator used to treat rheumatoid arthritis and systemic lupus erythematosus. In addition to its anti-inflammatory properties, HCQ reduces cholesterol and blood glucose levels and has antithrombotic effects. The drug is inexpensive and widely available. Adverse effects of HCQ are rare and occur more frequently with high doses.

OBJECTIVE

In this randomized clinical trial, the effect of HCQ treatment on endothelial function will be tested in seniors with sleep apnea.

METHODS

We will recruit participants over the age of 65 and with moderate-severe sleep apnea from an ongoing cohort. We chose to use this sample already evaluated for sleep apnea for reasons of convenience, but also because the elderly with sleep apnea are vulnerable to heart disease. Endothelial function will be assessed by examining flow-mediated dilation of the brachial artery, the gold standard method, considered an independent predictor of cardiovascular events in the general population and by peripheral arterial tonometry, the most recent and most easily obtained method. Hydroxychloroquine will be used at a dose of 400 mg/daily for 8 weeks.

DISCUSSION

Our study aims to obtain evidence, albeit preliminary, of the efficacy of hydroxychloroquine in improving endothelial function and reducing cardiovascular risk markers. If the improvement occurs, we plan to design a randomized multicenter clinical trial to confirm the findings.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04161339 . Registered on November 2019.

Obstructive sleep apnea, intermittent hypoxemia and prothrombotic biomarkers

Objective

To study the serum levels of fibrinogen and d-dimer in patients with obstructive sleep apnea (OSA) and its correlation with apnea hypopnea index (AHI), oxygen desaturation index (ODI), minimal oxygen saturation and arousal index.

Methods

It was a case control study in which 23 cases of OSA and 23 controls were enrolled. Morning fasting serum fibrinogen and d-dimer were measured in cases of OSA and controls.

Results

Serum fibrinogen levels among OSA patients (268.47±53.11mg/dl) were elevated as compared to the levels in controls (221.52±65.84mg/dl) (p<0.05). Serum fibrinogen co-related positively with AHI (r=0.6381, p=0.0011) and ODI (r=0.7434, p=0.0000), negatively with minimal oxygen saturation (r=-0.4461, p=0.0329). There was no statistically significant correlation of fibrinogen with arousal index (r=0.2697, p=0.2133). There was no statistically significant difference between mean fasting d-dimer level in cases (0.12mg/L, 0.06±0.18mg/L) and controls (0.12mg/L, 0.02±0.22mg/L) (p=0.8926).

Conclusions

The observation of elevated fibrinogen levels with the increasing severity of OSA and hypoxemic events makes OSA one of the important risk factor for cardiovascular disorders.

Cost-effectiveness Analysis of Preoperative Screening Strategies for Obstructive Sleep Apnea among Patients Undergoing Elective Inpatient Surgery

Background

Obstructive sleep apnea is underdiagnosed in surgical patients. The cost-effectiveness of obstructive sleep apnea screening is unknown. This study’s objective was to evaluate the cost-effectiveness of preoperative obstructive sleep apnea screening (1) perioperatively and (2) including patients’ remaining lifespans.

Methods

An individual-level Markov model was constructed to simulate the perioperative period and lifespan of patients undergoing inpatient elective surgery. Costs (2016 Canadian dollars) were calculated from the hospital perspective in a single-payer health system. Remaining model parameters were derived from a structured literature search. Candidate strategies included: (1) no screening; (2) STOP-Bang questionnaire alone; (3) STOP-Bang followed by polysomnography (STOP-Bang + polysomnography); and (4) STOP-Bang followed by portable monitor (STOP-Bang + portable monitor). Screen-positive patients (based on STOP-Bang cutoff of at least 3) received postoperative treatment modifications and expedited definitive testing. Effectiveness was expressed as quality-adjusted life month in the perioperative analyses and quality-adjusted life years in the lifetime analyses. The primary outcome was the incremental cost-effectiveness ratio.

Results

In perioperative and lifetime analyses, no screening was least costly and least effective. STOP-Bang + polysomnography was the most effective strategy and was more cost-effective than both STOP-Bang + portable monitor and STOP-Bang alone in both analyses. In perioperative analyses, STOP-Bang + polysomnography was not cost-effective compared to no screening at the $4,167/quality-adjusted life month threshold (incremental cost-effectiveness ratio $52,888/quality-adjusted life month). No screening was favored in more than 90% of iterations in probabilistic sensitivity analyses. In contrast, in lifetime analyses, STOP-Bang + polysomnography was favored compared to no screening at the $50,000/quality-adjusted life year threshold (incremental cost-effectiveness ratio $2,044/quality-adjusted life year). STOP-Bang + polysomnography was favored in most iterations at thresholds above $2,000/quality-adjusted life year in probabilistic sensitivity analyses.

Conclusions

The cost-effectiveness of preoperative obstructive sleep apnea screening differs depending on time horizon. Preoperative screening with STOP-Bang followed by immediate confirmatory testing with polysomnography is cost-effective on the lifetime horizon but not the perioperative horizon. The integration of preoperative screening based on STOP-Bang and polysomnography is a cost-effective means of mitigating the long-term disease burden of obstructive sleep apnea.

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Continuous positive pressure therapy usage and incident stroke in patients with obstructive sleep apnea: A nationwide population-based cohort study

INTRODUCTION

Continuous positive airway pressure (CPAP) is the main treatment for obstructive sleep apnea (OSA). To date, the link between CPAP usage and incident stroke has been inconsistent.

OBJECTIVE

This nationwide population study is designed to examine the effect of CPAP on stroke incidence in OSA patients.

METHODS

Using Taiwan's National Health Insurance Research Database (NHIRD), this study collected data from 4275 OSA patients diagnosed between 2000 and 2011 and divided them into two groups according to whether they received CPAP treatment. After matching baseline demographics and comorbidities, both cohorts contained 959 OSA patients and were followed to a newly diagnosed stroke or until the end of 2013. Cox regression analysis was performed to examine the incidence of stroke between patients with OSA receiving CPAP or no CPAP treatment.

RESULTS

CPAP treatment for OSA patients predicted a lower incidence rate (3.41 vs 5.43 per 1000 person-years) and tended to protect against the development of stroke (hazard ratio (HR): 0.68, 95% confidence interval (95% CI): 0.38-1.23) compared to those without CPAP treatment, but the estimate was not statistically significant. Similar results were also observed by dividing stroke into ischemic (2.65 vs 4.30 per 1000 person-years; HR: 0.67, 95% CI: 0.35-1.31) or hemorrhagic origin (0.76 vs 1.12 per 1000 person-years; HR: 0.67, 95% CI: 0.19-2.40).

CONCLUSIONS

It is possible that treatment with CPAP might be beneficial for protection against stroke, but this conclusion should be interpreted with caution. Future studies with satisfactory CPAP quality and duration are needed to validate this observation.

EAN/ERS/ESO/ESRS statement on the impact of sleep disorders on risk and outcome of stroke

Sleep disorders are highly prevalent in the general population and may be linked in a bidirectional fashion to stroke, which is one of the leading causes of morbidity and mortality.Four major scientific societies established a task force of experts in neurology, stroke, respiratory medicine, sleep medicine and methodology, to critically evaluate the evidence regarding potential links and the impact of therapy. 13 research questions were evaluated in a systematic literature search using a stepwise hierarchical approach: first, systematic reviews and meta-analyses; second, primary studies post-dating the systematic reviews/meta-analyses. A total of 445 studies were evaluated and 88 included. Statements were generated regarding current evidence and clinical practice.Severe obstructive sleep apnoea (OSA) doubles the risk for incident stroke, especially in young to middle-aged patients. Continuous positive airway pressure (CPAP) may reduce stroke risk, especially in treatment-compliant patients. The prevalence of OSA is high in stroke patients and can be assessed by polygraphy. Severe OSA is a risk factor for recurrence of stroke and may be associated with stroke mortality, while CPAP may improve stroke outcome. It is not clear if insomnia increases stroke risk, while pharmacotherapy of insomnia may increase it. Periodic limb movements in sleep (PLMS), but not restless limb syndrome (RLS), may be associated with an increased risk of stroke. Preliminary data suggest a high frequency of post-stroke insomnia and RLS and their association with a less favourable stroke outcome, while treatment data are scarce.Overall, the evidence base is best for OSA relationship with stroke and supports active diagnosis and therapy. Research gaps remain especially regarding insomnia and RLS/PLMS relationships with stroke.

Sleep Disturbances in Patients With Coronary Heart Disease: A Systematic Review

STUDY OBJECTIVES

Investigation into sleep and coronary heart disease (CHD) has predominantly been focused on sleep disturbances as a risk factor for developing CHD. Objectively measured and self-reported sleep at a patient level has only been sparsely and not systematically reported. Therefore, we set out to review the literature for studies using objectively measured and self-reported sleep in patients with CHD. The review focuses on patients with acute coronary syndrome (ACS) and stable CHD.

METHODS

A systematic review performed in four databases adhering to the PRISMA guidelines applying a qualitative synthesis of evidence.

RESULTS

Following ACS, we found sleep architecture to be significantly disturbed with changes normalizing over a period of up to 6 months. With increasing severity of CHD, sleep disturbances were more pronounced; however, the modulating effects of sleep-disordered breathing and ejection fraction on sleep in patients with CHD are conflicting. Overall, studies were predominantly cross-sectional in design and of low methodological quality. Polysomnography was the predominant outcome assessment tool and validated self-reported assessment tools were limited.

CONCLUSIONS

Future investigations in sleep and CHD applying both a longitudinal design and investigating objective and self-reported sleep assessments are warranted.

SYSTEMATIC REVIEW REGISTRATION

Registry: PROSPERO, Title: Sleep measures in relation to coronary heart disease: a systematic review, Identifier: CRD42017056377, URL: https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=56377.

Cerebral blood flow, oxygen metabolism, and lactate during hypoxia in patients with obstructive sleep apnea

Study Objectives

Obstructive sleep apnea (OSA) is associated with increased risk of stroke but the underlying mechanism is poorly understood. We suspect that the normal cerebrovascular response to hypoxia is disturbed in patients with OSA.

Methods

Global cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO2), and lactate concentration during hypoxia were measured in patients with OSA and matched controls. Twenty-eight patients (82.1% males, mean age 52.3 ± 10.0 years) with moderate-to-severe OSA assessed by partial polysomnography were examined and compared with 19 controls (73.7% males, mean age 51.8 ± 10.1 years). Patients and controls underwent magnetic resonance imaging (MRI) during 35 min of normoxia followed by 35 min inhaling hypoxic air (10%-12% O2). After 3 months of continuous positive airway pressure (CPAP) treatment, 22 patients were rescanned.

Results

During hypoxia, CBF significantly increased with decreasing arterial blood oxygen concentration (4.53 mL (blood)/100 g/min per -1 mmol(O2)/L, p < 0.001) in the control group, but was unchanged (0.89 mL (blood)/100 g/min per -1 mmol(O2)/L, p = 0.289) in the patient group before CPAP treatment. The CBF response to hypoxia was significantly weaker in patients than in controls (p = 0.003). After 3 months of CPAP treatment the CBF response normalized, showing a significant increase during hypoxia (5.15 mL (blood)/100 g/min per -1 mmol(O2)/L, p < 0.001). There was no difference in CMRO2 or cerebral lactate concentration between patients and controls, and no effect of CPAP treatment.

Conclusions

Patients with OSA exhibit reduced CBF in response to hypoxia. CPAP treatment normalized these patterns.

[The dynamics of cerebral vascular reserve in sleep apnea patients during continuous positive airway pressure therapy]

AIM

To explore the possibility of cerebral hemodynamic reserve (CHR) normalization in patients with obstructive sleep apnea syndrome (OSAS), aged over fifty, who received continuous positive airway pressure (CPAP) therapy.

MATERIAL AND METHODS

The main group (20 patients, aged 50-65 years, with severe OSAS) and the control group (20 volunteers without snoring and OSAS matched for age and physical status) were studied. Diagnosis included cardio-respiratory monitoring of nocturnal sleep and ultrasound examination of cerebral blood flow with functional tests (breath holding and hyperventilation) and calculating the coefficient of vasomotor reactivity (CVMR) before the start of CPAP-therapy and after one month therapy.

RESULTS

The significant CVMR decrease in vertebral (VA) and basilar arteries (BA) in patients with OSAS compared to the control group was identified: 38.9±8.5 and 55.7±11.3 for VA, 36.8±15.7 and 54.0±5.4 for BA. After one month CPAP-therapy, no significant coefficient gains was observed: 38.9±8.5 and 42.3±9.1 for VA, 36.8±15.7 and 37.2±7.7 for BA.

CONCLUSION

The reduction of CVMR in patients older than 50 years with severe OSAS suggests the disturbance of CHR. The absence of its recovery within one month of CPAP-therapy may be indicative of the irreversible damage of the cerebral blood flow regulation mechanisms. Continued observations for a longer period are needed.

Sleep Apnea, the Risk of Developing Heart Failure, and Potential Benefits of Continuous Positive Airway Pressure (CPAP) Therapy

Background

Whether there is an association between sleep apnea (SA) and the risk of developing heart failure (HF) is unclear. Furthermore, it has never been established whether continuous positive airway pressure (CPAP) therapy can prevent development of HF. We aimed to investigate SA patients’ risk of developing HF and the association of CPAP therapy.

Methods and Results

Using nationwide databases, the entire Danish population was followed from 2000 until 2012. patients with SA receiving and not receiving CPAP therapy were identified and compared with the background population. The primary end point was first‐time hospital contact for HF and adjusted incidence rate ratios of HF were calculated using Poisson regression models. Among 4.9 million individuals included, 40 485 developed SA during the study period (median age: 53.4 years, 78.5% men) of whom 45.2% received CPAP therapy. Crude rates of HF were increased in all patients with SA relative to the background population. In the adjusted model, the incidence rate ratios of HF were increased in the untreated SA patients of all ages, compared with the background population. Comparing the CPAP‐treated patients with SA with the untreated patients with SA showed significantly lower incidence rate ratios of HF among older patients.

Conclusions

In this nationwide cohort study, SA not treated with CPAP was associated with an increased risk of HF in patients of all ages. Use of CPAP therapy was associated with a lower risk of incident HF in patients >60 years of age, suggesting a protective effect of CPAP therapy in the elderly.

Cost-Effectiveness Analysis of the DiagnOSAS Screening Tool Compared With Polysomnography Diagnosis in Dutch Primary Care

STUDY OBJECTIVES

The growing recognition of obstructive sleep apnea (OSA) as a serious health condition, increasing waiting lists for sleep tests, and a high proportion of unnecessary referrals from general practice highlight the need for alternative diagnostic strategies for OSA. This study's objective was to investigate the cost-effectiveness of DiagnOSAS, a screening tool that strives to facilitate fast and well-informed referral to hospitals and sleep clinics for diagnosis, in The Netherlands.

METHODS

A Markov model was constructed to assess cost-effectiveness in men aged 50 years. The diagnostic process of OSA was simulated with and without DiagnOSAS, taking into account the occurrence of hazardous OSA effects: car accidents, myocardial infarction, and stroke. The cost-effectiveness of "DiagnOSAS Strategy" and a "Rapid Diagnosis Scenario," in which time to diagnosis was halved, was assessed.

RESULTS

Base case results show that, within a 10-year time period, DiagnOSAS saves €226 per patient at a negligible decrease (< 0.01) in quality-adjusted life-years (QALYs), resulting in an incremental cost-effectiveness ratio of €56,997/QALY. The "Rapid Diagnosis Scenario" dominates usual care (ie, is both cheaper and more effective). For a willingness-to-pay threshold of €20,000/QALY the probability that the "DiagnOSAS Strategy" and "Rapid Diagnosis Scenario" are cost-effective equals 91.7% and 99.3%, respectively.

CONCLUSIONS

DiagnOSAS appears to be a cost-saving alternative for the usual OSA diagnostic strategy in The Netherlands. When DiagnOSAS succeeds in decreasing time to diagnosis, it could substantially improve health outcomes as well.

Which place of pharmacological approaches beyond continuous positive airway pressure to treat vascular disease related to obstructive sleep apnea?

Obstructive sleep apnea (OSA) is characterized by recurrent episodes of partial or complete upper airway obstruction, occurring during sleep, leading to chronic intermittent hypoxia (IH), which harms the cardiovascular system. OSA is associated with both functional and structural vascular alterations that contribute to an increased prevalence of fatal and non-fatal cardiovascular events. OSA is a heterogeneous disease with respect to the severity of hypoxia, the presence of daytime symptoms, obesity, and cardiovascular comorbidities. Various clusters of OSA phenotypes have been described leading to more highly personalized treatment. The aim of this review is to describe the various therapeutic strategies including continuous positive airway pressure (CPAP), oral appliances, surgery, weight loss, and especially pharmacological interventions that have been evaluated to reduce vascular alterations in both OSA patients and preclinical animal models. Conventional therapies, predominantly CPAP, have a limited impact on vascular alterations in the presence of co-morbidities. A better knowledge of pharmacological therapies targeting IH-induced vascular alterations will facilitate the use of combined therapies and is crucial for designing clinical trials in well-defined OSA phenotypes.

Exercise, Occupational Activity, and Risk of Sleep Apnea: A Cross-Sectional Study

STUDY OBJECTIVES

To investigate whether structured exercise and occupational activity are associated with obstructive sleep apnea (OSA) severity.

METHODS

The International Physical Activity Questionnaire was answered by 5,453 individuals who underwent full-night polysomnography. Participants were classified as exercisers or non-exercisers and also as occupationally active or non-active. The apnea-hypopnea index (AHI), minimum oxygen saturation (SaO2min), and time with saturation below 90% (TB90%) during polysomnography were used as indicators of OSA severity.

RESULTS

The sample included mostly men (59%), non-exercisers (56%), and occupationally non-active individuals (75%). Mean age (± standard deviation) was 44 ± 14 years, and mean body mass index was 29.9 ± 7.3 kg/m2. Non-exercisers had higher AHI (median 14, 25-75% interquartile range 4-34) than exercisers (8 [2-24]), lower SaO2min (83 ± 9 vs. 86 ± 8%), and longer TB90% (2 [0-18] vs. 0 [0-7] minutes), with p < 0.001 for all comparisons. AHI was higher in active (16 [6-34]) vs. non-active occupations (10 [3-27]; p < 0.001). Multinomial logistic regression with control for age, sex, overweight, obesity, and occupational activity showed that structured exercise was significantly associated with a 23% lower odds ratio for moderate OSA and 34% lower odds ratio for severe OSA. Active occupation was not associated with OSA.

CONCLUSIONS

Structured physical exercise is associated with lower odds for OSA, independently of confounders. Occupational activity does not seem to replace the effects of regular exercise. Compensatory behaviors may be involved in these diverging outcomes. Our results warrant further research about the effect of occupational activity on OSA severity.

Serum from obstructive sleep apnea patients induces inflammatory responses in coronary artery endothelial cells

BACKGROUND AND AIMS

Obstructive sleep apnea (OSA) is characterized by intermittent airway obstruction and systemic hypoxia during sleep, which can contribute to an increase in reactive oxygen species, vascular remodeling, vasoconstriction and ultimately cardiovascular disease. Continuous positive airway pressure (CPAP) is a clinical therapy that maintains airway patency and mitigates several symptoms of OSA. However, it is currently unknown whether CPAP therapy also reduces the overall inflammatory potential in the circulation; to address this in an unbiased manner, we applied a novel endothelial biosensor approach, the serum cumulative inflammatory potential (SCIP) assay.

METHODS

We studied healthy controls (n = 7), OSA subjects receiving no treatment, (OSA controls) (n = 7) and OSA subjects receiving CPAP for 3 months (n = 8). Serum was obtained from OSA subjects before and after CPAP or no treatment. A battery of quantitative and functional assays was performed to assess the serum inflammatory potential, in terms of endothelial responses. For the SCIP assay, human coronary artery endothelial cells (hCAECs) were incubated with 5% serum in media from individual subjects for 4 h. qPCR was performed to assess endothelial inflammatory transcript (ICAM-1, VCAM-1, IL-8, P-selectin, CCL5, and CXCL12) responses to serum. Additionally, transendothelial resistance was measured in serum-incubated hCAECs following leukocyte challenge.

RESULTS

hCAECs exhibited significant increases in VCAM-1, ICAM-1, IL-8 and P-selectin mRNA when incubated with serum from OSA patients compared to serum from healthy control subjects. Furthermore, compared to no treatment, serum from CPAP-treated individuals was less potent at inducing inflammatory gene expression in the SCIP assay. Similarly, in a leukocyte adhesion assay, naïve cells treated with serum from patients who received CPAP exhibited improved endothelial barrier function than cells treated with OSA control serum.

CONCLUSIONS

OSA results in greater serum inflammatory potential, thereby driving endothelial activation and dysfunction.

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.

Psoriasis and Sleep Apnea: A Danish Nationwide Cohort Study

STUDY OBJECTIVES

Psoriasis and sleep apnea are associated with significant morbidity and mortality. Although both diseases have been linked with systemic inflammation, studies on their potential bidirectional association are lacking. We investigate the potential association between psoriasis and sleep apnea.

METHODS

All Danish citizens age 18 y or older between January 1, 1997 and December 31, 2011 (n = 5,522,190) were linked at individual level in nationwide registries. Incidence rates (IRs) per 10,000 person-years were calculated and incidence rate ratios (IRRs) adjusted for age, sex, socioeconomic status, smoking history, alcohol abuse, medication, and comorbidity were estimated by Poisson regression.

RESULTS

There were 53,290, 6,885, 6,348, and 39,908 incident cases of mild psoriasis, severe psoriasis, psoriatic arthritis, and sleep apnea, respectively. IRRs (95% confidence interval) for sleep apnea were 1.30 (1.17-1.44), 1.65 (1.23-2.22), and 1.75 (1.35-2.26) in subjects with mild and severe psoriasis, and psoriatic arthritis, and IRRs for mild and severe psoriasis, and psoriatic arthritis in sleep apnea without continuous positive airway pressure (CPAP) therapy were 1.62 (1.41-1.86), 2.04 (1.47-2.82), and 1.94 (1.34-2.79), respectively. In patients with sleep apnea and CPAP therapy (i.e., severe sleep apnea) the IRRs were 1.82 (1.43-2.33), 3.27 (2.03-5.27), and 5.59 (3.74-8.37), respectively.

CONCLUSIONS

Psoriasis was associated with increased risk of sleep apnea, and sleep apnea was associated with increased risk of psoriasis. The clinical significance of this bidirectional relationship warrants further study.

Can Continuous Positive Airway Pressure Reduce the Risk of Stroke in Obstructive Sleep Apnea Patients? A Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE

Obstructive sleep apnea (OSA) has been shown to increase the risk of stroke. Although continuous positive airway pressure (CPAP) is considered the treatment of choice for OSA, whether treating OSA with CPAP reduces the risk of stroke remains unclear. We aimed to evaluate the effects of CPAP on incidence of stroke in patients with OSA.

MATERIALS AND METHODS

We conducted a systematic review and meta-analysis of all published studies that provided the number of incident strokes in OSA patients in light of their treatment status with CPAP.

RESULTS

We identified 8 relevant studies: one randomized controlled study (RCT), 5 cohort studies, and 2 studies using administrative health data. The two overlapping cohort studies in women and the elderly and the 2 studies using administrative health data had analyzed the impact of CPAP on stroke apart from cardiac events, whereas the others had focused on the overall cardiovascular events. Based on a meta-analysis of the cohort studies, treatment with CPAP was associated with a lower incidence of stroke and cardiac events with relative risks of 0.27 [0.14-0.53], and 0.54 [0.38-0.75], respectively, although this could not be reproduced in the RCT and the studies using administrative data.

CONCLUSIONS

Treating with CPAP in patients with OSA might decrease the risk of stroke, although there is some conflicting evidence. Such effect was more pronounced in stroke than in cardiac events. Future studies analyzing stroke apart from cardiac disease would be of interest.

QT Interval Variability Index and QT Interval Duration in Different Sleep Stages: Analysis of Polysomnographic Recordings in Nonapneic Male Patients

The aim of the study was to determine whether different sleep stages, especially REM sleep, affect QT interval duration and variability in male patients without obstructive sleep apnea (OSA). Polysomnographic recordings of 30 patients were analyzed. Beat-to-beat QT interval variability was calculated using QTV index (QTVI) formula. For QTc interval calculation, in addition to Bazett's formula, linear and parabolic heart rate correction formulas with two separate α values were used. QTVI and QTc values were calculated as means of 2 awake, 3 NREM, and 3 REM sleep episodes; the duration of each episode was 300 sec. Mean QTVI values were not statistically different between sleep stages. Therefore, elevated QTVI values found in patients with OSA cannot be interpreted as physiological sympathetic impact during REM sleep and should be considered as a risk factor for potentially life-threatening ventricular arrhythmias. The absence of difference of the mean QTc interval values between NREM and REM stages seems to confirm our conclusion that sympathetic surges during REM stage do not induce repolarization variability. In patients without notable structural and electrical remodeling of myocardium, physiological elevation in sympathetic activity during REM sleep remains subthreshold concerning clinically significant increase of myocardial electrical instability.

Sleep, death, and the heart

Obstructive and central sleep apnea have been associated with increased risk of adverse cardiovascular events and mortality. Sympathetic dysregulation occurring as a result of the respiratory disturbance is thought to play a role in this increased risk. Sleep apnea increases the risk of arrhythmias, myocardial ischemia/infarction, stroke, and heart failure, all of which may increase mortality risk. A higher incidence of nocturnal arrhythmias, cardiac ischemia, and sudden death has been noted in subjects with sleep-disordered breathing (SDB). In this review, the association between SDB and each of these conditions is discussed, as well as the potential mechanisms underlying these risks and the effects of treatment of SDB. Particular emphasis is placed on the relationship between SDB and nocturnal atrial and ventricular arrhythmias, myocardial ischemia/infarction and sudden death.