Sleep-related breathing disorders and risk of stroke

High total bilirubin-to-uric acid ratio predicts poor sleep quality after acute ischemic stroke: a prospective nested case-control study

BACKGROUND

Sleep disorders are prevalent after stroke, resulting in high recurrence rates and mortality. But the biomarkers of sleep disorders in stroke patients remain to be elucidated. This study aimed to explore the relationship between total bilirubin-to-uric acid ratio (TUR) and sleep quality after acute ischemic stroke (AIS).

METHODS

Three hundred twenty-six AIS patients were recruited and followed up 1 month after stroke in our study. Serum total bilirubin and uric acid levels were obtained within 24 h after admission. The Pittsburgh Sleep Quality Index (PSQI) was used to evaluate sleep quality 1 month after stroke. We conducted receiver operating characteristic (ROC) curve analysis and screened the optimal biomarker to differentiate sleep disorders after stroke. Then the TUR was stratified according to the best cut-off value (0.036) of the ROC and further analysed by binary logistic regression analysis. Additionally, the interaction was used to explore the difference in its effect on post-stroke sleep quality in different subgroups.

RESULTS

Three hundred thirty-one patients (40.2%) were considered as having poor sleep quality during the one-month follow-up. Compared to patients with good sleep, patients with poor sleep were more likely to have higher TUR (IQR), 0.05 (0.03-0.06) versus 0.03 (0.02-0.04), P < 0.001. After adjusting for confounding factors, binary regression analysis demonstrated that a high TUR (≥0.036) was independently related to post-stroke poor sleep quality (OR = 3.75, 95% CI = 2.02-6.96, P < 0.001).

CONCLUSIONS

High TUR is associated with an increased risk of poor sleep quality in AIS patients, especially in females, diabetics, and patients with hyperlipidaemia.

Relationships between Heart Chamber Morphology or Function and Respiratory Parameters in Patients with HFrEF and Various Types of Sleep-Disordered Breathing

Sleep-disordered breathing (SDB), i.e., central sleep apnea (CSA) and obstructive sleep apnea (OSA), affects the prognosis of patients with heart failure with reduced ejection fraction (HFrEF). The study assessed the relationships between heart chamber size or function and respiratory parameters in patients with HFrEF and various types of SDB. The 84 participants were patients aged 68.3 ± 8.4 years (80% men) with an average left ventricular ejection fraction (LVEF) of 25.5 ± 6.85% who qualified for cardioverter-defibrillator implantation with or without cardiac resynchronization therapy. SDB, defined by an apnea-hypopnea index (AHI) ≥ five events/hour, was diagnosed in 76 patients (90.5%); SDB was severe in 31 (36.9%), moderate in 26 (31.0%), and mild in 19 (22.6%). CSA was the most common type of SDB (64 patients, 76.2%). A direct proportional relationship existed only in the CSA group between LVEF or stroke volume (SV) and AHI (p = 0.02 and p = 0.07), and between LVEF or SV and the percentage of total sleep time spent with hemoglobin oxygen saturation < 90% (p = 0.06 and p = 0.07). In contrast, the OSA group was the only group in which right ventricle size showed a positive relationship with AHI (for basal linear dimension [RVD1] p = 0.06), mean duration of the respiratory event (for RVD1 p = 0.03, for proximal outflow diameter [RVOT proximal] p = 0.009), and maximum duration of respiratory event (for RVD1 p = 0.049, for RVOT proximal p = 0.006). We concluded that in HFrEF patients, SDB severity is related to LV systolic function and SV only in CSA, whereas RV size correlates primarily with apnea/hypopnea episode duration in OSA.

Pathophysiology and probable etiology of cerebral small vessel disease in vascular dementia and Alzheimer's disease

Vascular cognitive impairment and dementia (VCID) is commonly caused by vascular injuries in cerebral large and small vessels and is a key driver of age-related cognitive decline. Severe VCID includes post-stroke dementia, subcortical ischemic vascular dementia, multi-infarct dementia, and mixed dementia. While VCID is acknowledged as the second most common form of dementia after Alzheimer's disease (AD) accounting for 20% of dementia cases, VCID and AD frequently coexist. In VCID, cerebral small vessel disease (cSVD) often affects arterioles, capillaries, and venules, where arteriolosclerosis and cerebral amyloid angiopathy (CAA) are major pathologies. White matter hyperintensities, recent small subcortical infarcts, lacunes of presumed vascular origin, enlarged perivascular space, microbleeds, and brain atrophy are neuroimaging hallmarks of cSVD. The current primary approach to cSVD treatment is to control vascular risk factors such as hypertension, dyslipidemia, diabetes, and smoking. However, causal therapeutic strategies have not been established partly due to the heterogeneous pathogenesis of cSVD. In this review, we summarize the pathophysiology of cSVD and discuss the probable etiological pathways by focusing on hypoperfusion/hypoxia, blood-brain barriers (BBB) dysregulation, brain fluid drainage disturbances, and vascular inflammation to define potential diagnostic and therapeutic targets for cSVD.

Sleep-related breathing disorders and cardiometabolic risk factors in pediatric kidney transplant recipients

BACKGROUND

SRBDs have been shown to increase the risk of cardiovascular disease, which is a significant cause of mortality in kidney transplant recipients. Few studies have investigated the association between SRBDs and cardiometabolic risk factors in pediatric kidney transplant recipients.

METHODS

This was a cross-sectional study of pediatric kidney transplant recipients using baseline cardiometabolic data from a previous clinical trial (NCT01007994). Parents/guardians of pediatric kidney transplant recipients filled out 22-item PSQ. A score greater than 33% was defined as a diagnosis of a SRBD. Fisher's exact test, Mann-Whitney U test, and regressions were used to determine associations.

RESULTS

Among the 58 transplant recipients enrolled, 14.80% (n = 8) of participants identified as Black and 40.7% (n = 22) were male. The median age was 13 (IQR 8.25, 17) years and median number of years post-transplant for participants was 2 (IQR 1, 4). The prevalence of SRBDs was 26% (n = 14). The presence of a SRBD was associated with abnormalities in multiple cardiometabolic risk factors including total cholesterol level (β = 23.63; 95% CI 3.58-43.67), LDL level (β = 24.94; 95% CI 6.37-43.50), triglyceride level (β = 54.62; 95% CI 8.74-100.50), and LVH (OR = 5.12; 95% CI 1.12-23.45) when adjusted for age, sex, and race.

CONCLUSIONS

Similar to associations reported in the general pediatric and general CKD populations, SRBD is associated with increased cardiometabolic risk in pediatric kidney transplant recipients.

Impact of intermittent hypoxia on human vascular responses during sleep

Exposure to intermittent hypoxia (IH) ≥15 times per hour is believed to be the primary mechanism for the increased risk of cerebrovascular and cardiovascular disease in patients with moderate to severe sleep apnea. Human experimental models of IH used to investigate this link have been predominantly employed during wakefulness, which limits extrapolation of findings to sleep apnea where IH occurs during sleep. Moreover, how IH impacts vascular regulation during sleep has not been measured quantitatively. Therefore, the objective of this study was to assess the impact sleep accompanied by IH on vascular responses to hypoxia and hypercapnia during sleep. Ten males performed two randomly scheduled 6-h overnight sleep studies. One sleep study was performed in room air (normoxia) and the other sleep study was performed during isocapnic IH (60 s hypoxia-60 s normoxia). On each night, cerebrovascular (peak blood velocity through the middle cerebral artery (V¯_P); transcranial Doppler ultrasound) and cardiovascular (blood pressure, heart rate) responses to hypoxia and hypercapnia were measured before sleep onset (PM-Awake), within the first 2 h of sleep (PM-Asleep), in the 5th (out of 6) hours of sleep (AM-Asleep) and after being awoken in the morning (AM-Awake). Sleep accompanied by IH had no impact on the V¯_P and blood pressure responses to hypoxia and hypercapnic at any timepoint (p ≥ 0.103 for all responses). However, the AM-Awake heart rate response to hypoxia was greater following sleep in IH compared to sleep in normoxia. Independent of the sleep environment, the V¯_P response to hypoxia and hypercapnia were reduced during sleep. In conclusion, cerebral blood flow responses are reduced during sleep compared to wakefulness, but 6 h of sleep accompanied by IH does not alter cerebrovascular and cardiovascular response to hypoxia and hypercapnia during wakefulness or sleep in healthy young humans. However, it is likely that longer exposure to IH during sleep (i.e., days-to-weeks) is required to better elucidate IH's impact on vascular regulation in humans.

The effect of chronic intermittent hypoxia in cardiovascular gene expression is modulated by age in a mice model of sleep apnea

STUDY OBJECTIVES

Chronic intermittent hypoxia (CIH) is a major determinant in obstructive sleep apnea cardiovascular morbidity and this effect is influenced by age. The objective of the present study was to assess the differential molecular mechanisms at gene-level expression involved in the cardiovascular remodeling induced by CIH according to chronological age.

METHODS

Two- and 18-month-old mice (N = 8 each) were subjected to CIH or normoxia for 8 weeks. Total messenger RNA (mRNA) was extracted from left ventricle myocardium and aortic arch, and gene expression of 46 intermediaries of aging, oxidative stress, and inflammation was measured by quantitative real-time polymerase chain reaction.

RESULTS

Cardiac gene expression of Nrf2 (2.05-fold increase, p < 0.001), Sod2 (1.9-fold increase, p = 0.035), Igf1r (1.4-fold increase, p = 0.028), Mtor (1.8-fold increase, p = 0.06), Foxo3 (1.5-fold increase, p = 0.020), Sirt4, Sirt6, and Sirt7 (1.3-fold increase, p = 0.012; 1.1-fold change, p = 0.031; 1.3-fold change, p = 0.029) was increased after CIH in young mice, but not in old mice. In aortic tissue, endothelial isoform of nitric oxide synthase was reduced in young mice (p < 0.001), Nrf2 was reduced in 80% (p < 0.001) in young mice and 45% (p = 0.07) in old mice, as its downstream antioxidant target Sod2 (82% reduced, p < 0.001). IL33.

CONCLUSIONS

CIH effect in gene expression is organ-dependent, and is modulated by age. CIH increased transcriptional expression of genes involved in cardioprotection and cell survival in young, but not in old mice. In aortic tissue, CIH reduced gene expression related to an antioxidant response in both young and old mice, suggesting vascular oxidative stress and a proaging process.

Greedy based convolutional neural network optimization for detecting apnea

BACKGROUND AND OBJECTIVE

Sleep apnea is a common sleep disorder, usually diagnosed using an expensive, highly specialized, and inconvenient test called polysomnography. A single SpO2 sensor based on an automated classification system can be developed to simplify the apnea detection. The main objective of this work is to develop a classifier based on a convolution neural network with the capability of detecting apnea events from one dimensional SpO2 signal. However, to find an optimum convolution neural network structure is a daunting task is usually done by a trial-and-error method. To solve this problem, a method is proposed to save time and simplify the process of searching for an optimum convolution neural network structure.

METHODS

Greedy based optimization is proposed to search for an optimized convolution neural network structure. Three different variants of greedy based optimization are proposed: the topology transfer, the weighted-topology transfer with rough estimation, and the weighted-topology transfer with fine tuning. The subject independent and the cross-database test are performed for the analysis.

RESULTS

Considering the balance between the execution time and the performance, the weighted-topology transfer with rough estimation is the best. An accuracy of 88.49% for the HuGCDN2008 database and 95.14% for the Apnea-ECG database are obtained for apnea events detection per minute. Regarding the apnea patient detection, also referred to as global classification, an accuracy of 95.71% is achieved for the HuGCDN2008 database, and 100% is achieved for the AED database without removing any subjects from both databases.

CONCLUSIONS

The proposed one-dimensional convolution neural network performs better in a similar situation than those presented in the literature. The greedy based methods, mainly the weighted-topology transfer with rough estimation, is an alternative method to extensive trial and error method.

Narrative review of sleep and stroke

Sleep disorders, such as sleep-disordered breathing (SDB), insomnia or restless legs syndrome (RLS), are common in the general population and after stroke. In some cases, sleep disturbances are pre-existing, but can also appear de novo as a direct consequence of brain damage or due to stroke-related complications. Furthermore, some sleep conditions may act as a risk factor of stroke. This review explores the available evidence of the two-way relationship between sleep and stroke. Cardiovascular physiological changes during sleep are described, as well as the evidence on the relationship between stroke and sleep duration, SDB, RLS, insomnia, excessive daytime sleepiness (EDS), and circadian rhythm alterations. Potential changes on sleep architecture, and the links that may exist between sleep and functional outcomes after stroke are also discussed. Importantly, sleep-related disturbances may be associated with worse stroke recovery outcomes and increased cerebrovascular morbidity. It is therefore relevant that the bidirectional association between stroke and sleep is taken into consideration by clinicians taking care of these patients. Future research may focus on this mutual relationship for a better understanding of the impact of stroke on sleep, the importance of sleep in stroke incidence and recovery, and have further evidence on treatment strategies that may improve functional outcome after stroke.

Choosing the right therapy for a patient with asymptomatic carotid stenosis

Introduction: Most patients with asymptomatic carotid stenosis (ACS) now have a lower risk with intensive medical therapy than with stenting (CAS) or endarterectomy (CEA); the annual risk of stroke or death with intensive medical therapy is ~ 0.5%, vs. a periprocedural risk with CAS of ~ 2.5-4.1% with CAS, and ~ 1.4-1.8% with CEA. The excess risk of CAS is greater in older patients.Areas covered: Discussed are the need for intensive medical therapy, the nature of intensive medical therapy, approaches to identifying the few patients with ACS who could benefit from CEA or CAS, and which patients would be better suited to CEA vs. CAS.Expert opinion: All patients with ACS are at high risk of cardiovascular events, soshould receive intensive medical therapy including lifestyle modification, intensive lipid-lowering, B vitamins to lower homocysteine (using methylcobalamin rather than cyanocobalamin), and appropriate antithrombotic therapy. High-risk patients who could benefit from intervention can be identified by clinical and imaging features including transcranial Doppler embolus detection, ulceration, intraplaque hemorrhage, reduced cerebrovascular reserve, plaque echolucency, silent infarction on brain imaging, and progression of stenosis. Most patients whose risk of stroke warrants intervention would be better treated with CEA than with CAS.

Impact of obstructive sleep apnea on silent cerebral small vessel disease: a systematic review and meta-analysis

BACKGROUND

Cerebral small vessel disease (CSVD) is a well-known cause of vascular dementia, a leading medical morbidity in the aging population. Obstructive sleep apnea (OSA) has been validated as a cardiovascular risk factor. However, the relationship between these two clinical syndromes is not well established. We aimed to assess the association between OSA and CSVD.

METHODS

Databases were searched from inception through May 2019. Studies that reported incidence or odd ratios of CSVD in patients with OSA were included. Effect estimates from the individual studies were extracted and combined using random-effect, generic inverse variance method of DerSimonian and Laird.

RESULTS

A total of 14 observational studies comprising of 4335 patients were included into the analysis. Compared to patients without OSA, patients with OSA were significantly associated with CSVD magnetic resonance imaging (MRI) findings of white matter hyperintensity (WMH) and asymptomatic lacunar infarction (ALI) with a pooled OR of 2.31 (95% confidence interval [CI], 1.46-3.66, I² = 79%) and 1.78 (95% CI, 1.06-3.01, I² = 41%), respectively. However, there was no significant association between OSA and findings of cerebral microbleeds (CMBs), with a pooled odds ratio (OR) of 2.15 (95% CI, 0.64-7.29, I² = 55%).

CONCLUSIONS

Our study demonstrated the association between OSA and CSVD MRI findings of white matter hyperintensity (WMH) and asymptomatic lacunar infarction (ALI) when compared to patients without OSA. The absence of an association of CMBs findings with OSA could be due either by a lower sensitivity of neuroimaging techniques utilized to detect CMBs or a potentially different pathogenesis of CMBs.

Improving obesity and blood pressure

Obesity-associated hypertension is a serious public health concern. Sympathetic nervous system (SNS) overactivity, especially in the kidneys, is an important mechanism linking obesity to hypertension. Some adipokines play important roles in elevating blood pressure (BP). Hyperinsulinemia caused by insulin resistance stimulates sodium reabsorption, enhances sodium retention, and increases circulating plasma volume. Hyperinsulinemia also stimulates both the renin-angiotensin-aldosterone system (RAAS) and the SNS, resulting in the acceleration of atherosclerosis through the hypertrophy of vascular smooth muscle cells, which contributes to increased peripheral vascular resistance. Obesity is associated with increased RAAS activity despite volume overload, as the tissue RAASs are stimulated in obese hypertensive individuals. Mineralocorticoid receptor-associated hypertension must also be considered in obese patients with resistant hypertension. Obstructive sleep apnea syndrome (OSAS) is the most common cause of secondary hypertension. Some components of the gut microbiota contribute to BP control; therefore, gut dysbiosis caused by obesity might lead to increased BP. The ratio of visceral fat to subcutaneous fat is higher in Japanese patients than in Caucasian patients, which may explain why Japanese patients are more susceptible to metabolic disorders even though they are less obese than Caucasian individuals. Obesity-associated kidney dysfunction directly increases BP, leading to further deterioration of kidney function. A bodyweight reduction of more than 3% or 5 kg significantly lowers BP. Gastrointestinal bypass surgery is an effective treatment for morbid obesity and its related metabolic disorders, including hypertension. Because both obesity and hypertension are representative lifestyle-related disorders, lifestyle modification, especially to improve obesity, should be performed first as a treatment for hypertension.

Human cerebral blood flow control during hypoxia: focus on chronic pulmonary obstructive disease and obstructive sleep apnea

The brain is a vital organ that relies on a constant and adequate blood flow to match oxygen and glucose delivery with the local metabolic demands of active neurons. Thus exquisite regulation of cerebral blood flow (CBF) is particularly important under hypoxic conditions to prevent a detrimental decrease in the partial pressure of oxygen within the brain tissues. Cerebrovascular sensitivity to hypoxia, assessed as the change in CBF during a hypoxic challenge, represents the capacity of cerebral vessels to respond to, and compensate for, a reduced oxygen supply, and has been shown to be impaired or blunted in a number of conditions. For instance, this is observed with aging, and in clinical conditions such as untreated obstructive sleep apnea (OSA) and in healthy humans exposed to intermittent hypoxia. This review will 1) provide a brief overview of cerebral blood flow regulation and results of pharmacological intervention studies which we have performed to better elucidate the basic mechanisms of cerebrovascular regulation in humans; and 2) present data from studies in clinical and healthy populations, using a translational physiology approach, to investigate human CBF control during hypoxia. Results from studies in patients with chronic obstructive pulmonary disease and OSA will be presented to identify the effects of the disease processes on cerebrovascular sensitivity to hypoxia. Data emerging from experimental human models of intermittent hypoxia during wakefulness will also be reviewed to highlight the effects of intermittent hypoxia on the brain.

The critical influence of nocturnal breathing complaints on the quality of sleep after stroke: the Pittsburgh Sleep Quality Index and STOP-BANG

ABSTRACT In stroke patients particularly, many factors, such as sleep-related respiratory disturbances, can impair sleep. Cheap and easy-to-use tools have been created to identify sleep quality and sleep disturbances in patients after stroke. This study described the scores of the sleep apnea screening questionnaire - STOP-BANG - in patients after a stroke, and correlated the findings with sleep quality measured by the Pittsburgh Sleep Quality Index (PSQI). The scores of the STOP-BANG and PSQI were 4.3 ± 1.8 and 76 ± 3.9, respectively. The STOP-BANG scores were higher in poor sleepers (4.5 ± 1.6 versus 3.5 ± 1.9; p = 0.032). Logistic regression analysis was used to identify predictors of subjective sleep quality (PSQI) and the STOP-BANG as a predictor of poor quality sleep, with a relative risk of 1.6, controlled for age and sex. This study indicated that sleep quality was largely influenced by sleep breathing problems, which were well identified by the STOP-BANG, especially in younger stroke patients.

Dynamic modeling of apnea induced concurrent variations in arterial blood pressure and cerebral blood flow velocity

Obstructive Sleep Apnea (OSA) is characterized by partial (hypopnea) or complete cessation (apnea) of airflow to the lungs during sleep. It has been previously reported that apnea episodes lead to significant rise in instantaneous blood pressure concomitant with a rise in cerebral blood flow velocity, indicating loss of cerebral autoregulation during the episodes. In this study, we have used Auto Regressive Moving Average model (ARMA (n_a, n_b, n_k)) to quantify OSA induced dynamic changes in cerebral blood flow velocity (CBFV) with beat to beat blood pressure (BP) as an input. BP and CBFV were recorded from 11 positively diagnosed sleep apnea subjects (6 Males, 5 Females; Age: 54.27±6.23 years, BMI:34.95±7.06kg/m², AHI: 57.39±28.43). The results suggest that two separate models, ARMA (5, 9, 1) and ARMA (5, 10, 0) can be used to quantify dynamic CBFV variations during apneas with a duration of less than and greater than 30s respectively with reasonable accuracy (<;6% error).

An improved design of optical sensor for long-term measurement of arterial blood flow waveform

We present here the improved design and development of optical sensor for non-invasive measurements of arterial blood flow waveform. The sensor is based on a physical principle of reflective photoplethysmography (PPG). As the light source we used serially connected infrared diodes whereas NPN silicon phototransistors were used as light detectors. The electronic components were molded into square package and poured with silicone. Such preparation produced an elastic superficies that allowed excellent attachment of the sensor on the skin's surface. Moreover, a serial connection of infrared diodes and phototransistors completely eliminated signal artifacts caused by minor muscle contractions. The sensor recording performances were examined at the photoplethysmographic sites on three different arteries; the commune carotid, femoral and radial and, on each site the sensor demonstrated remarkable capability to make a consistent, reproducible measurements. Because of the advantageous physical and electrical properties, the new sensor is suitable for various cardiovascular diagnostics procedures, especially when long-term measurements of arterial blood flow waveform are required, for monitoring of different parameters in cardiovascular units and for research.

Sleep and the Cardiovascular System in Children

Subspecialty pediatric practice provides comprehensive medical care for a range of ages, from premature infants to children, and often includes adults with complex medical and surgical issues that warrant multidisciplinary care. Normal physiologic variations involving different body systems occur during sleep and these vary with age, stage of sleep, and underlying health conditions. This article is a concise review of the cardiovascular (CV) physiology and pathophysiology in children, sleep-disordered breathing (SDB) contributing to CV morbidity, congenital and acquired CV pathology resulting in SDB, and the relationship between SDB and CV morbidity in different clinical syndromes and systemic diseases in the expanded pediatric population.

Development, Validation, and Assessment of an Ischemic Stroke or Transient Ischemic Attack-Specific Prediction Tool for Obstructive Sleep Apnea

BACKGROUND

Screening instruments for obstructive sleep apnea (OSA), as used routinely to guide clinicians regarding patient referral for polysomnography (PSG), rely heavily on symptomatology. We sought to develop and validate a cerebrovascular disease-specific OSA prediction model less reliant on symptomatology, and to compare its performance with commonly used screening instruments within a population with ischemic stroke or transient ischemic attack (TIA).

METHODS

Using data on demographic factors, anthropometric measurements, medical history, stroke severity, sleep questionnaires, and PSG from 2 independently derived, multisite, randomized trials that enrolled patients with stroke or TIA, we developed and validated a model to predict the presence of OSA (i.e., Apnea-Hypopnea Index ≥5 events per hour). Model performance was compared with that of the Berlin Questionnaire, Epworth Sleepiness Scale (ESS), the Snoring, Tiredness, Observed apnea, high blood Pressure, Body mass index, Age, Neck circumference, and Gender instrument, and the Sleep Apnea Clinical Score.

RESULTS

The new SLEEP Inventory (Sex, Left heart failure, ESS, Enlarged neck, weight [in Pounds], Insulin resistance/diabetes, and National Institutes of Health Stroke Scale) performed modestly better than other instruments in identifying patients with OSA, showing reasonable discrimination in the development (c-statistic .732) and validation (c-statistic .731) study populations, and having the highest negative predictive value of all in struments.

CONCLUSIONS

Clinicians should be aware of these limitations in OSA screening instruments when making decisions about referral for PSG. The high negative predictive value of the SLEEP INventory may be useful in determining and prioritizing patients with stroke or TIA least in need of overnight PSG.

Bodily pain, social support, depression symptoms and stroke history are independently associated with sleep disturbance among the elderly: a cross-sectional analysis of the Fujiwara-kyo study

OBJECTIVE

To investigate independent effects of various factors associated with sleep disturbance among community-dwelling elderly individuals.

METHODS

We analyzed data obtained from 3732 individuals aged ≥65 years who responded to a self-administered questionnaire and participated in a structured interview which assessed the Pittsburgh Sleep Quality Index (PSQI), subjective bodily pain, the Jichi Medical School Social Support Scale, the Geriatric Depression Scale (GDS-15), health status, and demographic characteristics. Sleep disturbance was defined as a global PSQI score >5.5, which was used as a dependent variable in multiple logistic regression analysis to determine adjusted odds ratios (ORs) and 95 % confidence intervals (CIs) of related factors.

RESULTS

We identified a significant increase in the adjusted ORs for female (OR 1.56, 95 % CI 1.34-1.83), age ≥80 years (1.31, 1.01-1.69), history of stroke (1.44, 1.08-1.92), and a GDS-15 score ≥6 as compared to 0-2 (2.29, 1.86-2.81), with regard to sleep disturbance. Participants with severe or very severe bodily pain had the highest adjusted OR (3.00, 2.15-4.19), and those with very mild bodily pain also had a relatively high OR (1.30, 1.06-1.60), relative to those without subjective bodily pain. In addition, compared with participants with strong social support from spouse or family, those with weak social support had significantly increased adjusted ORs (1.21, 1.01-1.44, 1.44, 1.23-1.70, respectively).

CONCLUSIONS

The present study indicates that sleeping disturbances among the elderly are closely associated with social support from a spouse and family. They are also associated with pain, even at stages in which subjective bodily pain is very mild.

Nocturnal Blood Pressure in Young Adults and Cognitive Function in Midlife: The Coronary Artery Risk Development in Young Adults (CARDIA) Study

BACKGROUND

Nocturnal blood pressure (BP) is associated with risk for cardiovascular events. However, the relationship between nocturnal BP in young adults and cognitive function in midlife remains unclear.

METHODS

We used data from the ambulatory BP monitoring substudy of the Coronary Artery Risk Development in Young Adults Study, including 224 participants (mean age 30 years, 45% men, 63% African Americans). At the 20-year follow-up, the Stroop test (executive function), Digit Symbol Substitution Test (psychomotor speed), and Rey Auditory Verbal Learning Test (verbal memory) were assessed.

RESULTS

Baseline mean office, daytime, and nocturnal BP were 109/73, 120/74, and 107/59 mm Hg, respectively. Nocturnal BP dipping, calculated as (nocturnal systolic BP [SBP]--daytime SBP) × 100/daytime SBP, was divided into quartiles (Q1: -39.3% to -16.9%; Q2: -16.8% to -13.2%, Q3 [reference]: -13.1% to -7.8%, and Q4: -7.7% to +56.4%). In multiple regression analyses, the least nocturnal SBP dipping (Q4 vs. reference) and higher nocturnal diastolic BP level were associated with worse Stroop scores, with adjustments for demographic and clinical characteristics, and cumulative exposure to office BP during follow-up (β [standard error]: 0.37 [0.18] and 0.19 [0.07], respectively; all P < 0.05). Digit Symbol Substitution Test and Rey Auditory Verbal Learning Test were not significantly associated with nocturnal SBP dipping or nocturnal SBP/diastolic BP levels.

CONCLUSIONS

Among healthy young adults, less nocturnal SBP dipping and higher nocturnal diastolic BP levels were associated with lower executive function in midlife, independent of multiple measures of office BP during long-term follow-up.

Putting sleep apnea to rest

Sleep apnea, the periodic cessation of breathing during sleep, is a common and underdiagnosed condition. Treatment can improve quality of life as well as reduce morbidity and mortality from sleep apnea-related hypertension, stroke, and traffic accidents. In this article, the authors discuss types of sleep apnea, diagnostic tools, and treatment strategies for both adults and children.

One Year Outcome of Acute Stroke Patients with Sleep Apnea

The aim of this study was to analyze one year outcome of the acute stroke patients with sleep apnea in order to gender and age.

METHODS

It was analyzed 110 patients with acute stroke and sleep apnea. Among them 65(59%) were men. Average age of all participant was 65.13±9.27 years. The same number and gender distribution of participants with stroke and without apnea were in control group. Evaluation of sleep apnea has been done with: "The Sleep Disorders Questionnaire", "Berlin Questionnaire to identify patients at risk for the sleep apnea syndrome" and "The Epworth Sleepiness Scale".

RESULTS

One year after stroke onset survived 91 (82.7%) out of 110 patients with apnea. Average age of survived patients was 63.66±8.78 years. Among them 52(80%) were men. In control group, without apnea survived 104 (94.5%) patients with average age of 65.00±8.62 years. Among them 62 (95.4%) were men. In men with apnea there is significantly lower survival range in order to patients without apnea (X(2)=8.22, p=0.004). In women there is no difference. Survival of both gender in patients with apnea (22; 64.7%) was the lowest in group older than 70 years of age. Sex ratio (men : women) was 15 (68.2%):7(58.3%). Survival in both gender in patients without apnea was the same in group older than 70 years of age: 27 (81.2%) out of 33. Average age of patients who died with apnea was significantly higher in order to patients without (t=1.97, p=0.03).

CONCLUSION

One year after stroke, significantly more patients survived without (94.5%) than with apnea (82.7%) (p=0.01). In order to sex survived range was significantly (p=0.004) lover in men with apnea than without but in women there is no difference. Survival range of both gender in patients with apnea was the lowest in group older than 70 years (p=0.03).

Links between ectopic fat and vascular disease in humans

The average of overweight individual can have differential fat depots in target organs or specific compartments of the body. This ectopic fat distribution may be more of a predictive factor for cardiovascular risk than obesity. Abdominal visceral obesity, a representative ectopic fat, is robustly associated with insulin resistance and cardiovascular risk. Fat depots in the liver and muscle tissue cause adverse cardiometabolic risk by affecting glucose and lipid metabolism. Pericardial fat and perivascular fat affect coronary atherosclerosis, cardiac function, and hemodynamics. Fat around the neck is associated with systemic vascular resistance. Fat around the kidney may increase blood pressure and induce albuminuria. Fat accumulation in or around the pancreas alters glucose metabolism, conferring cardiovascular risk. Ectopic fat may act as an active endocrine and paracrine organ that releases various bioactive mediators that influence insulin resistance, glucose and lipid metabolism, coagulation, and inflammation, which all contribute to cardiovascular risk. Because both obese and apparently lean individuals can have ectopic fat, regional fat distribution may play an important role in the development of cardiovascular diseases in both nonobese and obese people.

Nonarteritic anterior ischemic optic neuropathy and obstructive sleep apnea

BACKGROUND

To evaluate the obstructive sleep apnea syndrome (OSAS) in patients with nonarteritic anterior ischemic optic neuropathy (NAION).

METHODS

We recruited 27 patients with NAION and 27 age-matched and sex-matched controls who also were similar for systemic risk factors such as diabetes mellitus, hypertension, and hypercholesterolemia. All patients and controls underwent overnight polysomnography for the diagnosis of OSAS and calculation of apnea-hypopnea index (AHI).

RESULTS

Patients and controls were statistically similar in terms of age, sex, gender, smoking, systemic risk factors, neck circumference, and body mass index. The subjects with AHI ≥ 20 were accepted as OSAS. Fifteen of 27 patients (55.6%) with NAION and 6 of 27 controls (22.2%) had OSAS (P < 0.05).

CONCLUSION

The prevalence of OSAS was higher in patients with NAION, and the difference between patient and control groups was statistically significant (P < 0.05). This result supports prior series suggesting the association between NAION and OSAS.

Normal-tension glaucoma and obstructive sleep apnea syndrome: a prospective study

BACKGROUND

Today, identified risk factors for normal-tension glaucoma (NTG) include abnormal ocular blood flow, abnormal blood coagulation, systemic hypotension, ischemic vascular disorders, and autoimmune diseases. However, pathogenesis of the condition remains unclear. On the other hand, there are also a few studies suggesting that the obstructive sleep apnea syndrome (OSAS) may compromise optic nerve head perfusion and cause glaucomatous optic neuropathy by creating transient hypoxemia and increasing vascular resistance. In this study, we evaluated the possible association between OSAS and NTG.

METHODS

We recruited 24 patients with NTG and 24 age and sex matched controls who were also similar for systemic risk factors such as diabetes mellitus (DM), hypertension (HT) and hypercholesterolemia. All patients and controls underwent over-night polysomnography (PSG) for the diagnosis of OSAS and calculation of Apnea-Hypopnea Index (AHI).

RESULTS

Patients and controls were statistically similar in terms of age, sex, gender, smoking, systemic risk factors, neck circumference and body mass index. The subjects with AHI ≥ 20 were accepted as OSAS. Ten (41.7%) of 24 patients with NTG and 3 (12.5%) of 24 controls had OSAS (p < 0.05).

CONCLUSIONS

The prevalence of OSAS was higher in patients with NTG and the difference between patient and control groups was statistically significant (p < 0.05).

What is known about the experiences of using CPAP for OSA from the users' perspective? A systematic integrative literature review

Economic, social and personal costs of untreated obstructive sleep apnoea (OSA) are high. Continuous positive airway pressure (CPAP) is recommended and cost effective. Increasing OSA prevalence may accompany predicted globally increasing obesity.

OBJECTIVE

To synthesise international evidence regarding personal experiences using CPAP for OSA.

METHODS

A systematic integrative literature review was conducted and quality assessment criteria applied.

RESULTS

22, of 538, identified papers met inclusion criteria. Thematic analysis identified three themes: 1) users' beliefs about CPAP influence users' experiences of CPAP; 2) CPAP users are primed to reflect negatively on experiences of CPAP; and 3) spouse and family influence users' experiences of CPAP. Personality and attitude impact expectations about CPAP prior to use, whilst engagement of spouse and family also influence experiences. Analysis highlighted that users' reporting of CPAP experiences is constrained by investigator defined assessment methods. Overall, research relating to experiences using CPAP is limited.

CONCLUSION

Users' perspectives of CPAP are constrained by researchers' concern with non-compliance. Typically experiences are not defined by the user, but from an 'expert' healthcare perspective, using words which frame CPAP as problematic. Family and social support is a significant, but neglected area of experiencing CPAP warranting further investigation. More information from users is required to determine how CPAP can be managed successfully.

Ectopic fat and cardiometabolic and vascular risk

Given that the variation in how regional adipose tissue handles and stores excess dietary energy has substantial cardiometabolic implications, ectopic fat distribution might be an important predictor of cardiometabolic and vascular risk, in addition to overall obesity itself. Conceptually, ectopic fat depots may be divided into systemically acting fat depots and locally acting fat depots. Systemically acting fat depots include visceral fat, fat in the liver, muscle, or neck, and subcutaneous fat. Accumulation in the abdominal visceral area, compared with overall obesity, has an equally or more important role in the development of cardiometabolic risk. Fat depots in liver/muscle tissue cause adverse cardiometabolic effects by affecting energy metabolism. Fat depots in lower-body subcutaneous areas may be protective regarding cardiometabolic risk, by trapping remnant energy. Fat accumulation in the neck is a unique type of fat depot that may increase cardiovascular risk by increasing insulin resistance. Locally acting fat depots include pericardial fat, perivascular fat, and renal sinus fat. These fat depots have effects primarily on adjacent anatomic organs, directly via lipotoxicity and indirectly via cytokine secretion. Pericardial fat is associated with coronary atherosclerosis. Perivascular fat may play an independent role in adverse vascular biology, including arterial stiffness. Renal sinus fat is a unique fat depot that may confer additional cardiometabolic risk. Thus, ectopic fat depots may contribute to the understanding of the link between body composition and cardiometabolic risk. In this review, we focus on the role and clinical implications of ectopic fat depots in cardiometabolic and vascular risk.

Capnography screening for sleep apnea in patients with acute stroke

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

Baroreflex and chemoreflex controls of sympathetic activity following intermittent hypoxia

There is a large amount of evidence linking obstructive sleep apnea (OSA), and the associated intermittent hypoxia that accompanies it, with the development of hypertension. For example, cross-sectional studies demonstrate that the prevalence of hypertension increases with the severity of OSA (Bixler et al., 2000; Grote et al., 2001) and an initial determination of OSA is associated with a three-fold increase for future hypertension (Peppard et al., 2000). Interestingly, bouts of intermittent hypoxia have also been shown to affect sympathetic output associated with the baroreflex and chemoreflex, important mechanisms in the regulation of arterial blood pressure. As such, the possibility exists that changes in the baroreflex and chemoreflex may contribute to the development of chronic hypertension observed in OSA patients. The aim of the current article is to briefly review the response of the baroreflex and chemoreflex to intermittent hypoxic exposure and to evaluate evidence for the hypothesis that modification of these autonomic reflexes may, at least in part, support the comorbidity observed between chronic hypertension and OSA.

Fibrinolytic activity and platelet function in subjects with obstructive sleep apnoea and a patent foramen ovale: is there an option for prevention of ischaemic stroke?

Obstructive sleep apnoea (OSA) carries an increased risk of ischaemic stroke, but the underlying mechanism is not clear. As right-to-left shunting can occur through a patent foramen ovale (PFO) during periods of apnoea, we investigated nocturnal changes in fibrinolytic activity and platelet function in subjects who had OSA with or without PFO and in controls. We determined plasminogen activator inhibitor 1 (PAI-1) activity and antigen and platelet activation parameters. The severity of OSA was verified by polygraphy and PFO was detected by ear oximetry. We found a higher PAI-1 activity and antigen and a lower ratio of 2,3-dinor-PGF(1α) to 2,3-dinor-TXB(2) in the subjects with OSA than in the controls. Linear regression analysis showed the apnoea-hypopnoea index (β-coefficient, 0.499; P = 0.032) and PFO (β-coefficient, 0.594; P = 0.015) to be associated independently with PAI-1 activity in the morning, while the increment in PAI-1:Ag from evening to morning was significantly associated with the presence of PFO (r(s) = 0.563, P = 0.002). Both OSA and PFO reduce fibrinolytic activity during nocturnal sleep. We hypothesize that subjects having both OSA and PFO may develop a more severe prothrombotic state during sleep than those having either OSA or PFO alone.

The association of obesity with insulin resistance in male patients with obstructive sleep apnea syndrome in Korea

OBJECTIVE

Obstructive sleep apnea syndrome (OSAS) has been associated with cardiovascular complications and insulin resistance has been implicated in the pathogenesis and progression of atherosclerosis. We investigated whether insulin resistance is associated with OSAS independent of obesity.

METHODS

A total of 183 male patients with OSAS and 52 healthy controls were assessed by nocturnal polysomnography (NPSG). After NPSG, serum concentrations of total cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides, glucose and insulin were measured. Insulin resistance was determined by calculating the homeostasis model assessment for insulin resistance (HOMA-IR).

RESULTS

Subjects were divided into normal control, mild-to-moderate OSA group (n=96) and severe OSA group (n=87). There were no significant differences among groups in age, body mass index (BMI), neck circumference or waist circumference. Serum concentrations of total cholesterol, LDL cholesterol, triglycerides, glucose, insulin and HOMA-IR scores of normal controls did not differ from those of the mild-to-moderate or severe OSAS groups. HOMA-IR significantly correlated with anthropometric variables, oxygen desaturation index, triglyceride and LDL cholesterol. Stepwise multiple linear regression analysis showed that waist circumference (β=0.35) and triglycerides (β=0.27) were significant determinants of HOMA-IR (adjusted R(2)=20%, p<0.01).

CONCLUSION

Insulin resistance was related to obesity itself rather than OSAS severity or nocturnal hypoxemia-related variables. In preventing cardiovascular complications in OSAS patients, weight reduction should be considered.

Patent foramen ovale and obstructive sleep apnoea: from pathophysiology to diagnosis of a potentially dangerous association

Patent foramen ovale and obstructive sleep apnoea are frequently encountered in the general population. Owing to their prevalence, they may coexist fortuitously; however, the prevalence of patent foramen ovale seems to be higher in patients with obstructive sleep apnoea. We have reviewed the epidemiological data, pathophysiology, and the diagnostic and therapeutic options for both patent foramen ovale and obstructive sleep apnoea. We focus on the interesting pathophysiological links that could explain a potential association between both pathologies and their implications, especially on the risk of stroke.

Safety and tolerability of early noninvasive ventilatory correction using bilevel positive airway pressure in acute ischemic stroke

BACKGROUND AND PURPOSE

Hypercapnia can induce intracranial blood-flow steal from ischemic brain tissues, and early initiation of noninvasive ventilator correction (NIVC) may improve cerebral hemodynamics in acute ischemic stroke. We sought to determine safety and tolerability of NIVC initiated on hospital admission without polysomnography study.

SUBJECTS AND METHODS

Consecutive acute ischemic stroke patients were evaluated for the presence of a proximal arterial occlusion, daytime sleepiness, or history of obstructive sleep apnea, and acceptable pulse oximetry readings while awake (96%-100% on 2 to 4 L supplemental oxygen delivered by nasal cannula). NIVC was started on hospital admission as standard of care when considered necessary by treating physicians. NIVC was initiated using bilevel positive airway pressure at 10 cmH(2)O inspiratory positive airway pressure and 5 cmH(2)O expiratory positive airway pressure in combination with 40% fraction of inspired oxygen. All potential adverse events were prospectively documented.

RESULTS

Among 356 acute ischemic stroke patients (median NIHSS score, 5; interquartile range, 2-13), 64 cases (18%) received NIVC (median NIHSS score, 12; interquartile range, 6-17). Baseline stroke severity was higher and proximal arterial occlusions were more frequent in NIVC patients compared to the rest (P<0.001). NIVC was not tolerated by 4 patients (7%). Adverse events in NIVC included vomiting (n=1), aspiration pneumonia (n=1), respiratory failure/intubation (n=1), hypotension requiring pressors (n=1), and facial skin breakdown (n=3). The in-hospital mortality rate was 13% in NIVC patients and 8% in the rest (P=0.195). Neurological improvement during hospitalization tended to be greater in the NIVC group (median NIHSS score decrease, 2 points; interquartile range, 0-4) compared to the rest (median NIHSS score decrease, 1; interquartile range, 0-2; P=0.078).

CONCLUSIONS

In acute ischemic stroke patients with proximal arterial occlusion and excessive sleepiness or obstructive sleep apnea, NIVC can be initiated early with good tolerability and a relatively small risk of serious complications.

Heart rate variability in childhood obstructive sleep apnea

The identification of patients with obstructive sleep apnea (OSA) is important because of morbidities associated with OSA. A previous adult study demonstrated the use of heart rate variability (HRV) as a tool to identify patients with moderate to severe OSA. Either a reduction in time parameters or an increase in LF/HF ratio was seen at overnight or 24-hr studies suggestive of increased sympathetic modulation. To study the feasibility of daytime HRV as a screening tool, a short-term recording of HRV is studied. Since it was shown in adult study that increased normalized LF, decreased normalized HF and increased LF/HF ratio could be detectable during supine rest at daytime awake period, the authors hypothesize that the differences are also detectable in children. Children who underwent sleep polysomnography for suspected OSA were recruited. Subjects were classified OSA if apnea-hypopnea index (AHI) > 1.5/hr and non-OSA if AHI ≤ 1.5/hr. Continuous 1-hr electrocardiographic monitoring was recorded in awake children during the day. Parameters from time domain and frequency domain were analyzed. Seventy-four male and 17 female snoring subjects were included in this study. Fifty-one (56%) and 40 (44%) of them were classified as "non-OSA" and "OSA," respectively. pNN50, a parameter for parasympathetic modulation, was significantly reduced in the OSA group when compared with the non-OSA group. Using multiple regression, all time domain variables were shown to be decreased in OSA group. Our results suggest that 1-hr study of HRV may be a feasible tool in identifying children with OSA.

Differences in left ventricular cardiomyocyte loss induced by chronic intermittent hypoxia between spontaneously hypertensive and Wistar-Kyoto rats

RATIONALE

Chronic intermittent hypoxia (CIH) is thought to induce several cardiovascular effects in patients with obstructive sleep apnoea (OSA). However, the effects of CIH on patients with long-standing hypertension are unknown.

PURPOSE

This prospective study aimed to investigate the influence of combined OSA and hypertension on cardiomyocyte death.

METHODS

Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) were exposed to repetitive hypoxia-reoxygenation cycles (30 s of 5% O(2); 45 s of 21% O(2)) or room air for 6 h/day during the light phase (10 a.m.-4 p.m.) for 10, 20, or 30 days, and the levels of necrosis and apoptosis induced in their left ventricular cardiomyocyte were examined.

RESULTS

CIH increased the accumulation of reactive oxygen species, which induced cardiomyocyte necrosis in WKY and SHR (both p < 0.05). Cardiomyocyte oxidative stress levels by CIH were higher in SHR than in WKY (p < 0.05); therefore, cardiomyocyte necrosis was amplified (p < 0.05). Notably, if a superoxide-scavenging agent is injected beforehand, cardiomyocyte necrosis can be effectively inhibited (p < 0.05). When WKY and SHR are exposed to CIH, increases in mitochondria-released cytochrome c and activation of caspase-3 are found in the cytosolic fraction only in WKY.

CONCLUSIONS

CIH causes cardiomyocyte loss in SHR mainly through cardiomyocyte necrosis. In WKY however, CIH simultaneously induces apoptosis and necrosis of cardiomyocytes.

Strokes and their relationship with sleep and sleep disorders

INTRODUCTION

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

DEVELOPMENT

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

CONCLUSIONS

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

Making a Case for Acute Ischemic Stroke

Stroke is the third leading cause of death in the United States and the number one cause of adult long-term disability. Disability in stroke survivors includes hemiparesis, aphasia, inability to walk without assistance, dependence on others for activities of daily living, depression, and institutionalization. Immediate recognition of acute ischemic stroke (AIS) signs and symptoms is required because many treatment options are time sensitive. Hospital transport via activation of 911 and emergency medical services (EMSs) removes delays to urgent diagnosis and intervention. Intravenous (IV) recombinant tissue plasminogen (rt-PA) is a time-sensitive reperfusion strategy. The American Heart Association (AHA) and American Stroke Association (ASA) recently revised recommendations that the time window for IV rt-PA be expanded from 3 hours to 4.5 hours after symptom onset in patients with mild to moderate stroke. Supportive therapies include crystalloid IV solutions, adequate oxygenation, and normothermia. Best rest is desired along with oxygen supplementation. Avoidance of fever is paramount since fever can contribute to negative outcomes. It is the purpose of this article to review risk factors, stroke symptoms, epidemiology, and current drug therapy of AIS. Standards of care will be reviewed.