Obstructive Sleep Apnea in Cardiovascular Disease: A Review of the Literature and Proposed Multidisciplinary Clinical Management Strategy

Extracting signature responses from respiratory flows: Low-dimensional analyses on Direct Numerical Simulation-predicted wakes of a flapping uvula

Uvula-induced snoring and associated obstructive sleep apnea is a complex phenomenon characterized by vibrating structures and highly transient vortex dynamics. This study aimed to extract signature features of uvula wake flows of different pathological origins and develop a linear reduced-order surrogate model for flow control. Six airway models were developed with two uvula kinematics and three pharynx constriction levels. A direct numerical simulation (DNS) flow solver based on the immersed boundary method was utilized to resolve the wake flows induced by the flapping uvula. Key spatial and temporal responses of the flow to uvula kinematics and pharynx constriction were investigated using continuous wavelet transform (CWT), proper orthogonal decomposition (POD), and dynamic mode decomposition (DMD). Results showed highly complex patterns in flow topologies. CWT analysis revealed multiscale correlations in both time and space between the flapping uvular and wake flows. POD analysis successfully separated the flows among the six models by projecting the datasets in the vector space spanned by the first three eigenmodes. Perceivable differences were also captured in the time evolution of the DMD modes among the six models. A linear reduced-order surrogate model was constructed from the predominant eigenmodes obtained from the DMD analysis and predicted vortex patterns from this surrogate model agreed well with the corresponding DNS simulations. The computational and analytical platform presented in this study could bring a variety of applications in breathing-related disorders and beyond. The computational efficiency of surrogate modeling makes it well suited for flow control, forecasting, and uncertainty analyses.

Globular adiponectin alleviates chronic intermittent hypoxia-induced H9C2 cardiomyocytes apoptosis via ER-phagy induction

This study evaluated the effects of endoplasmic reticulum autophagy (ER-phagy) and globular adiponectin (gAPN) on chronic intermittent hypoxia (CIH)-induced H9C2 cardiomyocytes injury while investigating potential mechanisms of action. The CIH model of H9C2 cardiomyocytes was established in this study. CCK-8 assay was used to determine cell viability post-exposure to various CIH times and gAPN concentrations. Flow cytometry was used to observe H9C2 cardiomyocytes apoptosis and immunofluorescence was used to measure ER-phagy and SEC62 activation. Western blot was used to observe ER stress and AMPK pathway. Results indicated that ER stress was activated in H9C2 cardiomyocytes exposed to CIH. Inhibition of ER stress reduced CIH-induced cell apoptosis. gAPN attenuated CIH-induced ER stress and H9C2 cardiomyocytes apoptosis. ER-phagy and SEC62 protein level were induced by CIH, while gAPN highly enhanced these changes. Inhibition of SEC62 expression reduced ER-phagy and increased ER stress and H9C2 cardiomyocytes apoptosis. Moreover, gAPN induced AMPK expression. Inhibition of AMPK expression reduced SEC62-mediated ER-phagy and increased the H9C2 cardiomyocytes apoptosis. Altogether, our study suggested that gAPN upregulated SEC62-mediated ER-phagy to extenuate ER stress, and mitigated H9C2 cardiomyocytes apoptosis induced by CIH through AMPK activation.

A New Approach for Detecting Sleep Apnea Using a Contactless Bed Sensor: Comparison Study

Background

At present, there is an increased demand for accurate and personalized patient monitoring because of the various challenges facing health care systems. For instance, rising costs and lack of physicians are two serious problems affecting the patient’s care. Nonintrusive monitoring of vital signs is a potential solution to close current gaps in patient monitoring. As an example, bed-embedded ballistocardiogram (BCG) sensors can help physicians identify cardiac arrhythmia and obstructive sleep apnea (OSA) nonintrusively without interfering with the patient’s everyday activities. Detecting OSA using BCG sensors is gaining popularity among researchers because of its simple installation and accessibility, that is, their nonwearable nature. In the field of nonintrusive vital sign monitoring, a microbend fiber optic sensor (MFOS), among other sensors, has proven to be suitable. Nevertheless, few studies have examined apnea detection.

Objective

This study aims to assess the capabilities of an MFOS for nonintrusive vital signs and sleep apnea detection during an in-lab sleep study. Data were collected from patients with sleep apnea in the sleep laboratory at Khoo Teck Puat Hospital.

Methods

In total, 10 participants underwent full polysomnography (PSG), and the MFOS was placed under the patient’s mattress for BCG data collection. The apneic event detection algorithm was evaluated against the manually scored events obtained from the PSG study on a minute-by-minute basis. Furthermore, normalized mean absolute error (NMAE), normalized root mean square error (NRMSE), and mean absolute percentage error (MAPE) were employed to evaluate the sensor capabilities for vital sign detection, comprising heart rate (HR) and respiratory rate (RR). Vital signs were evaluated based on a 30-second time window, with an overlap of 15 seconds. In this study, electrocardiogram and thoracic effort signals were used as references to estimate the performance of the proposed vital sign detection algorithms.

Results

For the 10 patients recruited for the study, the proposed system achieved reasonable results compared with PSG for sleep apnea detection, such as an accuracy of 49.96% (SD 6.39), a sensitivity of 57.07% (SD 12.63), and a specificity of 45.26% (SD 9.51). In addition, the system achieved close results for HR and RR estimation, such as an NMAE of 5.42% (SD 0.57), an NRMSE of 6.54% (SD 0.56), and an MAPE of 5.41% (SD 0.58) for HR, whereas an NMAE of 11.42% (SD 2.62), an NRMSE of 13.85% (SD 2.78), and an MAPE of 11.60% (SD 2.84) for RR.

Conclusions

Overall, the recommended system produced reasonably good results for apneic event detection, considering the fact that we are using a single-channel BCG sensor. Conversely, satisfactory results were obtained for vital sign detection when compared with the PSG outcomes. These results provide preliminary support for the potential use of the MFOS for sleep apnea detection.

Pharmacologic heart failure treatment: A case-based review of current guidelines

ABSTRACT

Heart failure (HF) is a growing health problem associated with high morbidity and mortality. Use of evidence-based therapies improves clinical outcomes in patients with HF with reduced ejection fraction (HFrEF). However, in real-world research studies, adults with HFrEF were often medically undermanaged, including failure to use the right medications and failure to up titrate core HF therapies to doses similar to those used in randomized controlled trials. Although guidelines provide best-practice statements about care management, nurse practitioners and physician assistants (NPs and PAs) and clinical nurses often have questions about how to implement guideline-directed therapies in patient care management. With emerging new medications for managing HFrEF, and the possibility of new medications for patients with HF with preserved ejection fraction, complexity of care management will continue to increase. The aims of this review are to provide a summary of the 2017 updates to the national chronic HF management guidelines and use a case-based approach to discuss treatment change considerations associated with optimal guideline-based clinical care.

Long-Term Effects of Continuous Positive Airway Pressure (CPAP) Therapy on Obesity and Cardiovascular Comorbidities in Patients with Obstructive Sleep Apnea and Resistant Hypertension-An Observational Study

BACKGROUND

We sought to investigate whether long-term continuous positive airway pressure (CPAP) treatment in patients with obstructive sleep apnea (OSA) and resistant hypertension (RHTN) could attenuate the cardiovascular disease risk by lowering their body-mass index (BMI).

METHODS

This was a long-term observational study of RHTN patients diagnosed with OSA. Patients were evaluated with polysomnography initially and after a mean follow-up period of four years. The patients were divided into two groups based on their compliance to CPAP therapy.

RESULTS

33 patients (aged 54.67 ± 7.5, 18 men, 54.5%) were included in the study, of which 12 were compliant to CPAP therapy. A significant reduction in BMI at follow-up was noted in patients compliant to CPAP therapy (1.4 ± 3.5 vs. -1.6 ± 2.5, p = 0.006). We also noted a large effect size reduction in abdominal circumference at follow-up in the CPAP group. At follow-up evaluation, the mean heart rate (b/min) was lower in the CPAP group (58.6 ± 9.5 vs. 67.8 ± 7.8), while arrhythmia prevalence increased between initial (28.6%) and follow-up (42.9%) evaluation with an intermediate effect size in non-compliant patients.

CONCLUSIONS

In our cohort of OSA patients with RHTN, long-term adherence to CPAP therapy was associated with weight loss and improvement in cardiac rhythm outcomes.

[Clinical profile of patients with obstructive sleep apnea syndrome in a cardiology hospital]

RELEVANCE

Obstructive sleep apnea syndrome (OSAS) is an important medical and social problem due to its high prevalence and impact on quality of life. The relationship between OSAS and cardiovascular pathology has been proven by many studies, which confirms the necessity for early diagnosis of OSAS and its treatment for the prevention of fatal and non-fatal events.

AIM

to study epidemiological and clinical profile of the patients referred by a cardiologist to a specialized sleep laboratory to verify the diagnosis of OSAS.

MATERIALS AND METHODS

Object of study 527 patients aged 56.912.5 years who were hospitalized to the Myasnikov Clinical Cardiology Research Institute from 20162018 and had OSAS risk factors. Initially, complaints, medical history, anthropometric data were collected. As a screening survey, questionnaires were conducted using questionnaire scales. Verification of the diagnosis of OSAS and determination of the severity was carried out by cardiorespiratory or respiratory monitoring. Subsequently, 4 groups were formed depending on the presence and severity of OSAS.

RESULTS

The prevalence of OSAS among patients in a cardiology hospital referred to a verification study was 88.6%. A comparative analysis of the groups revealed a progressive increase in the values of anthropometric indicators with increasing severity of OSAS. No differences were found between the groups by gender and daytime sleepiness on the Karolinska Sleepiness Scale. The average score on the Epworth sleepiness scale was statistically significantly lower only in the group of patients without OSAS when compared with the group with a severe degree of OSAS, and is comparable with the scores in the groups of mild and moderate degrees of OSAS. In a multivariate model of logistic regression, independent predictors of OSAS were identified as: age over 45 years, indications of loud intermittent snoring, frequent nightly urination, overweight or obesity. According to the results of assessing the incidence of various cardiovascular diseases in patients referred to the sleep laboratory, no significant differences were detected. At the same time, a significant difference was found in the frequency of obesity in patients with severe OSAS compared with other groups, as well as the frequency of type 2 diabetes mellitus or impaired glucose tolerance when compared with groups without OSAS, and with mild OSAS. In one-factor logistic regression models, it was found that the likelihood of having a severe degree of OSAS increases with increasing both comorbidity and age.

CONCLUSIONS

High prevalence of OSAS in patients of a cardiological hospital, referred to a sleep laboratory for verification study, was confirmed. Considering the data that early diagnosis and treatment of OSAS can affect the course of both nosologies, the quality of life and prognosis of these patients, it is advisable to routinely screen and verify the diagnosis of OSAS in patients with cardiovascular diseases.

Prevalence of obstructive sleep apnoea in acute coronary syndrome patients: systematic review and meta-analysis

Background

Obstructive Sleep Apnoea (OSA) has been recognised as a risk factor for cardiovascular diseases such as hypertension and cardiovascular events such as acute coronary syndrome (ACS). Since it is also known to reduce exercise tolerance, it is important to establish the prevalence of OSA in ACS patients, particularly in those who are commencing cardiac rehabilitation (CR) programs.

Methods

Using PRISMA guidelines a systematic search was conducted in order to identify studies that objectively measured (using polysomnography or portable monitoring) the prevalence of OSA in ACS patients following hospital admission. A data extraction table was used to summarise study characteristics and the quality of studies were independently assessed using the Joanna Briggs Institute Prevalence Critical Appraisal Tool. Meta-analysis of the selected studies was conducted in order to estimate OSA prevalence as a function of the two main methods of measurement, the severity of OSA, and timing of the OSA assessment following ACS hospital admission.

Results

Pooled prevalence estimates of OSA using the “gold standard” polysomnography ranged from 22% for severe OSA to 70% for mild OSA, at any time after hospital admission. Similar prevalence estimates were obtained using portable monitoring, but interpretation of these results are limited by the significant heterogeneity observed among these studies.

Conclusions

Prevalence of OSA following ACS is high and likely to be problematic upon patient entry into CR programs. Routine screening for OSA upon program entry may be necessary to optimise effectiveness of CR for these patients.

The cardiovascular risk in paediatrics: the paradigm of the obstructive sleep apnoea syndrome

BACKGROUND

Obstructive sleep apnoea syndrome (OSAS) describes a spectrum of abnormal breathing patterns during sleep characterised by snoring, increased upper airway resistance and pharyngeal collapsibility, with alteration of normal oxygenation and ventilation. Intermittent desaturations during sleep have multi-organ implications. Adults with OSAS have an increased risk of developing a dysfunctional endothelium that is characterised by greater adherence of inflammatory mediators to endothelial cells and hypercoagulability. There is increasing evidence to show that risk factors for comorbid cardiovascular disease (CVD) can develop during childhood and adolescence and are likely to continue over time. Risk factors for CVD include both modifiable factors and factors that cannot be changed.

MATERIALS AND METHODS

Using the MEDLINE^® electronic database, we reviewed the scientific literature for published studies evaluating the association between sleep-disordered breathing and cardiovascular damage in children.

RESULTS

In this review, we show the role of blood markers in demonstrating the inflammation caused by intermitted oxygen desaturations during sleep in both healthy and obese children. Several instrumental techniques, in addition to serum biomarkers, can be used to assess vascular endothelial damage and its deterioration in the form of a pre-atherosclerotic condition. The confirmation of their role as markers of inflammation and vascular damage is supported by normalisation after resolution or improvement of the sleep-disordered breathing with surgery.

DISCUSSION

Great attention should be given to this condition in infants and children as it will significantly affect their present and future well-being as they grow into adulthood. Healthcare professionals, especially paediatricians, should be trained to recognise the signs and symptoms of the disease in order to send children forward for specialist care in centres dealing with sleep-disordered breathing.

Thiol-disulfide as a novel indicator of obstructive sleep apnea

INTRODUCTION

Obstructive sleep apnea (OSA) is an oxidative stress disease, which has been considered to be a notable risk and associated with increased cardiovascular morbidity and mortality. Thiol-disulfide homeostasis is as a novel indicator of oxidative stress.

OBJECTIVES

We aimed to evaluate thiol-disulfide homeostasis in a large patient population with OSA.

METHODS

A total of 230 with OSA and 40 healthy controls were included in the study. Inclusion criteria for OSA patients are having apnoea-hypopnoea index of ≥5/hour, being more than 18 years of age and having no previous treatment for OSA. Thiol-disulfide analysis was done for the patients and control group. Blood thiol-disulfide homeostasis was analysed using the new automatic method, developed by Erel and Neşelioğlu.

RESULTS

Among all OSA subjects, 149 (64.8%) were males and the mean ages of the patients were 53.38 ± 10.22. Total thiol, native thiol (SH) and disulfide (SS) levels were significantly lower in OSA group compared to the control group (P < .001, P < .001 and P = .039 respectively). Also, total thiol and native thiol (SH) were significantly different between the groups according to OSA severity (mild-moderate to severe OSA) (P < .001 and P < .001 respectively). Thiol-disulfide redox parameters were correlated with apnoea-hypopnoea index (AHI) scores.

CONCLUSION

The present prospective study showed that thiol/disulfide homeostasis was unbalanced in OSA patients. Especially, in OSA patients have low level of thiol/disulfide redox parameters when compared to healthy subjects. Evaluating thiol-disulfide homeostasis in OSA may be a contributing aspect to assessment and monitoring of the patient.

Obstructive Sleep Apnoea Syndrome: Continuous Positive Airway Pressure Therapy for Prevention of Cardiovascular Risk

Obstructive sleep apnoea (OSA) syndrome is characterised by the presence of apnoea or obstructive hypopnoea during sleep, accompanied by hypoxia. It is estimated that the syndrome affects approximately 10% of men and 15% of women. Diagnosis and treatment rates have increased in recent years, but the condition remains undiagnosed in a high percentage of patients. Recent evidence suggests that OSA may increase the risk of cardiovascular disease. The relationship between OSA and cardiovascular disease can be explained, at least in part, by the coexistence of cardiovascular risk factors in the two pathologies, such as age, overweight, smoking and sedentary lifestyle. However, OSA has been independently associated with the risk of developing hypertension, cerebrovascular disease, ischaemic heart disease, heart failure and arrhythmias. Clinical trials that have evaluated the efficacy of continuous positive airway pressure (CPAP) treatment in primary and secondary cardiovascular prevention have not demonstrated a significant reduction in the incidence or recurrence of cardiovascular events. This article analyses the relationship between OSA and cardiovascular risk and discusses recent clinical trials on the efficacy of CPAP in primary and secondary cardiovascular prevention.

Adult obstructive sleep apnoea: Pathogenesis, importance, diagnosis and imaging

Obstructive sleep apnoea (OSA) is a serious worldwide health problem. Moderate-to-severe OSA has been found in up to 50% of men and 25% of women in the middle-aged population. It results in a fourfold increase in all causes of mortality. The prevalence of OSA is underestimated, partly due to absence of symptoms but also lack of knowledge amongst the population at large as well as sectors of the medical profession. Imaging, performed predominantly by clinicians and research scientists, has been integral to evaluating the anatomical basis of OSA. Increased nasal resistance and a narrowed and elongated oropharynx lead to increased collapsibility of the upper airway, predisposing to airway collapse and apnoea during sleep when there is reduction in tone of the pharyngeal dilator muscles. Unfortunately, a significantly narrowed upper airway is usually ignored by radiologists: it is not part of their reporting 'check-list'. The imaging findings in the upper airway that are strongly associated with OSA and its sequelae in various organ systems are discussed. Imaging can strongly suggest OSA; the diagnosis requires a polysomnogram for confirmation. Treatment of moderate-to-severe disease is primarily with positive airway pressure applied by a nasal or oral mask which splints the upper airway. Although highly effective, compliance is limited and other treatment modalities are increasingly being utilized.

Autonomic Dysfunction Increases Cardiovascular Risk in the Presence of Sleep Apnea

The high prevalence of sleep apnea syndrome (SAS) and its direct relationship with an augmented risk of cardiovascular disease (CVD) have raised SAS as a primary public health problem. For this reason, extensive research aiming to understand the interaction between both conditions has been conducted. The advances in non-invasive autonomic nervous system (ANS) monitoring through heart rate variability (HRV) analysis have revealed an increased sympathetic dominance in subjects suffering from SAS when compared with controls. Similarly, HRV analysis of subjects with CVD suggests altered autonomic activity. In this work, we investigated the altered autonomic control in subjects suffering from SAS and CVD simultaneously when compared with SAS patients, as well as the possibility that ANS assessment may be useful for the early stage identification of cardiovascular risk in subjects with SAS. The analysis was performed over 199 subjects from two independent datasets during night-time, and the effects of the physiological response following an apneic episode, sleep stages, and respiration on HRV were taken into account. Results, as measured by HRV, suggest a decreased sympathetic dominance in those subjects suffering from both conditions, as well as in subjects with SAS that will develop CVDs, which was reflected in a significantly reduced sympathovagal balance (p < 0.05). In this way, ANS monitoring could contribute to improve screening and diagnosis, and eventually aid in the phenotyping of patients, as an altered response might have direct implications on cardiovascular health.