Pathophysiologic mechanisms of cardiovascular disease in obstructive sleep apnea syndrome. Pulm Med. 2013;2013:521087. [PMID: 23936649 PMCID: PMC3712227 DOI: 10.1155/2013/521087]

The effect of CPAP therapy on heart rate variability in patients with obstructive sleep apnea

The aim of this study was to analyze the relationship between the initiation of CPAP therapy and HRV in patients with OSA. The study group consisted of 37 patients, aged 34-79 (mean 54.95 years) with OSA treated with CPAP. Two subgroups of patients were distinguished: less than severe (AHI < 30, n = 16) and severe OSA (AHI ≥ 30, n = 21). The second study was carried out around a month after the initiation of therapy. CPAP therapy caused the improvement in polysomnographic parameters, however, in most parameters in time and frequency analysis, there were no significant positive changes in parasympathetic tone. Moreover, in HRV time analysis, the reduced rMSSD and pNN50 parameters in the hours of night rest and rMSSD and SDSD during the 15-min N3 sleep period were noted. Especially, in the group with AHI ≥ 30, we observed significant decreases in rMSSD and pNN50 for the entire time. The changes were mainly for the night periods including the N3 sleep period, which is especially connected with sleep apnea (parameters: rMSSD, SDSD, and pNN50). In spectral analysis, the decrease in HF from the 15-min daily activity period and the N3 sleep period was observed. Inverse correlations were seen between the maximum, median, and mean positive airway pressure (PAP) and the change in rMSSD, SDNN, and SDSD, mainly during night hours and the N3 sleep period. Only in patients with AHI < 30 the increase in SDNN was observed in 15-min N3 sleep period. The beneficial increase in SDNN parameter from time analysis was observed only in one sleep period in less ill patients with OSA. The lack of significant changes was observed in the majority of the parameters of heart rate variability after initiation of CPAP therapy in a short observational time; however, the shift towards reduced HRV was observed in patients with AHI > 30, so the response to CPAP therapy may depends on the severity of the apnea. The results may suggest that a longer observational period is needed in such studies, and the problem is still not fully elucidated.

A trial of positive airway pressure for the treatment of sleep apnea in pregnancy

BACKGROUND

The pathophysiology of obstructive sleep apnea in pregnancy remains poorly understood and studies examining the effect of treatment with positive airway pressure on pregnancy have been limited.

OBJECTIVE

This study aimed to perform a randomized controlled trial of positive airway pressure treatment for obstructive sleep apnea in pregnancy.

STUDY DESIGN

Participants with a body mass index ≥30 kg/m² underwent polysomnography at 14 to 20 weeks' gestation (visit 1) and those with obstructive sleep apnea (apnea-hypopnea index ≥5 but <50) were enrolled. In phase 1, participants were randomized to autotitrating positive airway pressure vs sham positive airway pressure; in phase 2, the sham arm was replaced with a sleep hygiene control. Participants returned at 28 to 31 weeks' gestation (visit 2). The mean arterial blood pressure, uterine artery Doppler pulsatility index, endoglin, soluble FMS-like tyrosine kinase 1 levels, and placental growth factor levels were measured, as well as fasting glucose and insulin to calculate insulin resistance (homeostatic model assessment for insulin resistance). The primary outcome was a composite of the uterine artery Doppler pulsatility index, soluble FMS-like tyrosine kinase 1 to placental growth factor ratio, and the homeostatic model assessment for insulin resistance. For secondary analyses, each outcome variable was analyzed independently. Adherence to treatment was examined.

RESULTS

A total of 241 participants completed visit 1, and 89 (37%) had an apnea-hypopnea index between 5 and 50. Of the those, 51 participants were randomized in phase 1 and 38 in phase 2. There was no significant difference in our primary outcome by treatment group. In secondary analyses, the uterine artery Doppler pulsatility index was lower in participants on autotitrating positive airway pressure when compared with sleep hygiene controls. Otherwise, there were no differences in the mean arterial blood pressure, angiogenic markers, or metabolic markers in phase 1, phase 2, or across the entire study. The overall adherence to autotitrating positive airway pressure therapy was low, but the mean use was greater in phase 2 (0.3±0.6 hours/night vs 1.3±2.3 hours/night; P=.10). For those on active therapy, fasting glucose values decreased as adherence increased.

CONCLUSION

This randomized controlled trial of autotitrating positive airway pressure in pregnancy did not find any differences in a composite primary cardiometabolic risk profile between the treatment groups. Higher autotitrating positive airway pressure adherence was associated with lower fasting glucose levels. The use of a sham positive airway pressure control arm in phase1 may have negatively impacted adherence to active treatment.

The association between sleep-disordered breathing and maternal endothelial and metabolic markers in pregnancies complicated by obesity

STUDY OBJECTIVES

To evaluate the impact of sleep-disordered breathing (SDB) on vascular, angiogenic and metabolic analytes in pregnancy.

METHODS

Participants with a body mass index ≥30 kg/m2 underwent polysomnography at 14-20 weeks gestation (visit 1). Participants with SDB (defined as an apnea-hypopnea index ≥5 events/h) were then enrolled in a separate trial. SDB-negative participants returned for a polysomnogram at 28-31 weeks (visit 2) and were recategorized as persistent-negative SDB or new-onset SDB. Mean arterial blood pressure, mean uterine artery Doppler pulsatility index, endoglin, soluble Feline McDonough Sarcoma-like tyrosine kinase 1, placental growth factor, and the homeostatic model assessment for insulin resistance were measured after each visit. Our primary outcome was a composite of uterine artery Doppler pulsatility index, soluble FMS-like tyrosine kinase 1/placental growth factor ratio, and homeostatic model assessment for insulin resistance. For secondary analyses, each outcome variable was analyzed independently.

RESULTS

A total of 242 and 130 participants completed visit 1 and visit 2, respectively. Newly diagnosed SDB was present in 37% of individuals at visit 1 and 31% of individuals at visit 2. No significant differences in our composite outcome vector were observed in individuals with and without SDB at either visit. In our secondary analysis, mean arterial blood pressure (88.7 ± 7.3 mm Hg vs 85.4 ± 7.1 mm Hg, P = .04) and fasting glucose (92.4 ± 15.2 mg/dL vs 86.6 ± 11.5 mg/dL, P = .05) were higher in participants with early pregnancy SDB. These associations were not observed for new-onset SDB. No associations were observed between uterine artery Doppler pulsatility index and angiogenic markers and SDB in pregnancy.

CONCLUSIONS

SDB in early pregnancy was not associated with our composite primary outcome but was associated with higher mean arterial blood pressure and fasting glucose. The pathophysiologic changes that occur in pregnant individuals with SDB and how they lead to an increased risk of preeclampsia and gestational diabetes remain poorly understood.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Sleep Disordered Breathing, Obesity and Pregnancy Study (SOAP); URL: https://clinicaltrials.gov/ct2/show/NCT02086448; Identifier: NCT02086448.

CITATION

Onslow ML, Wolsk J, Wisniewski S, et al. The association between sleep-disordered breathing and maternal endothelial and metabolic markers in pregnancies complicated by obesity. J Clin Sleep Med. 2023;19(1):97-109.

Choroidal vascularity index in obstructive sleep apnea syndrome

BACKGROUND

There is growing evidence supporting an association between obstructive sleep apnea syndrome (OSAS) and systemic vascular disorders. However, the data on choroidal microvasculature are limited. In recent years, choroidal thickness (CT) and choroidal vascularity index (CVI) have been of considerable interest as objective markers of choroidal vascularity. We hypothesized that the imbalance of vascular regulation in OSAS may adversely affect the CT and CVI and may help to assess the vascular risk in these patients.

PURPOSE

This study aimed to evaluate the choroidal morphology in patients with OSAS.

MATERIALS AND METHODS

Patients with moderate OSAS were included to this study. The subfoveal, nasal, and temporal CT were calculated. The choroidal area (CA) was binarized to the luminal area (LA) and stromal area (SA) using ImageJ software. The CVI was calculated as the proportion of the LA to the total CA.

RESULTS

Of 40 eyes of 40 patients, the mean subfoveal CT was significantly decreased in the OSAS group in comparison to the controls (p = 0.032). The mean CA, LA, and SA were decreased in the OSAS group compared with the controls, but the differences did not reach a statistical significance (p = 0.132, p = 0.104, and p = 0.184, respectively). The CVI was not significantly changed in patients with OSAS (p = 1.000).

CONCLUSION

Unlike CT, there were no significant differences in choroidal structural parameters and CVI in patients with OSAS.

The Assessment of Endothelial Dysfunction among OSA Patients after CPAP Treatment

Background and Objectives: Microcirculation dysfunction is present in patients with obstructive sleep apnea (OSA). Intermittent hypoxia generates “oxidative stress”, which contributes to chronic inflammation. The secretion of nitric oxide (NO), which is responsible for adequate regulation of the endothelium, is impaired due to a decrease in endothelial nitric oxide synthetase (eNOS) expression and an increase in endogenous eNOS inhibitors. Furthermore, nocturnal awakenings lead to the dysregulation of cortisol release and increased stimulation of the sympathetic nervous system. The non-invasive method of choice in OSA treatment is continuous positive airway pressure (CPAP). Materials and Methods: PubMed, Scopus, and Google Scholar databases were searched, and only papers published in the last 15 years were subsequently analyzed. For this purpose, we searched for keywords in article titles or contents such as “obstructive sleep apnea”, “microcirculation”, and “CPAP”. In our review, we only studied English articles that reported systemic reviews and meta-analyses, clinical studies, and case reports. Results: Endothelial dysfunction can be assessed by methods based on reactive hyperemia, such as flow-mediated dilation (FMD) measured by ultrasonography, laser-Doppler flowmetry (LDF), or capillaroscopy. In invasive techniques, intravenous administration of vasodilator substances takes place. Some surveys detected impaired microcirculation in OSA patients compared with healthy individuals. The level of dysfunction depended on the severity of OSA. CPAP treatment significantly improved endothelial function and microvascular blood flow and lowered the inflammatory mediator level. Conclusions: The first-choice treatment—CPAP—reduces the number of apneas and hypopneas during the night, induces the reversal of hypopnea and the chronic inflammatory state, and enhances activation of the sympathetic nervous system. Changes are visible as improved blood flow in both macro- and microcirculation, increased arterial elasticity, and decreased stiffness. Thus, early implementation of adequate treatment could be essential to reduce high cardiovascular risk in patients with OSA.

Is the Oxidative Stress in Obstructive Sleep Apnea Associated With Cardiovascular Complications?-Systematic Review

Obstructive sleep apnea (OSA) is a prevalent, underdiagnosed disease and is considered an independent risk factor for cardiovascular disease. The exact mechanism of cardiovascular complications (CVC) development as a complication of OSA is not entirely understood. Oxidative stress is suspected to be the essential factor in initiating various comorbidities in OSA. Biomarkers of nonenzymatic lipid and protein peroxidation, DNA repair and antioxidant capabilities measured in serum, plasma and urine are frequently used to assess the presence of oxidative stress. We conducted a systematic review and quality assessment of available observational analytic studies to determine whether there is an association between oxidative stress and OSA in patients with prevalent CV disease compared to (a) patients with prevalent CV disease but no OSA, (b) patients with prevalent CV disease and less severe OSA and (c) patients with OSA and no overt CV disease. This systematic review demonstrated that, while oxidative stress is associated with OSA, there was no clear difference in the severity of oxidative stress between OSA patients with or without cardiovascular complications.

Obstructive sleep apnea, sleep symptoms, and their association with cardiovascular disease

OBJECTIVES

To determine the frequency of obstructive sleep apnea (OSA), insomnia, restless legs, and other sleep symptoms in patients with cardiovascular disease and the association of these sleep disorders with quantitative cardiovascular measures.

METHODS

Study design was a cross-sectional survey and retrospective chart review. A questionnaire containing validated sleep symptoms was distributed to 202 patients with cardiovascular disease at a tertiary referral cardiology clinic. Following a focused review of these patients' medical charts, their questionnaire responses were examined for associations with clinical cardiovascular parameters.

RESULTS

Twenty-one percent of patients reported a prior diagnosis of OSA. A total of 115 patients (60%) had at least one additional sleep symptom. Clinically significant insomnia was significantly associated with heart disease (relative risk [RR] = 1.5, confidence interval [CI] = 1.1 to 2.1), prior myocardial infarction or cerebrovascular accident (RR = 2.1, CI = 1.2 to 3.6), and heart failure (RR = 2.2, CI = 1.3 to 3.8). Left ventricular ejection fraction was significantly associated with insomnia by Insomnia Severity Index (β = -0.52, CI = -0.89 to -0.13).

CONCLUSION

The frequency of OSA in patients in this tertiary cardiology clinic was higher than the general population in the United States, with the majority of patients experiencing at least one sleep symptom. Insomnia symptoms were shown to be associated with multiple cardiovascular measures, including left ventricular ejection fraction. These findings imply an interwoven relationship between cardiovascular and sleep symptoms as captured by validated sleep questionnaires.

LEVEL OF EVIDENCE

IV Laryngoscope, 130:1595-1602, 2020.

Relationship Between Sleep Apnea and Coronary Artery Calcium in Patients With Ischemic Stroke

Study Objectives: Coronary artery disease is considered to be the major cause of death amongst patients with ischemic stroke. The coronary artery calcium (CAC) score is related not only to sleep-disordered breathing, but also with future risk of cardiovascular mortality. We investigated the association between the severity of sleep-disordered breathing and CAC score in patients with ischemic stroke.

Methods: We included 32 patients who underwent coronary multichannel computed tomography and polysomnography (within 2 years of the stroke event) amongst the patients admitted to our clinic due to acute ischemic stroke. We investigated vascular risk factors, polysomnography findings, and sleep questionnaire scores, and their relationships with the CAC score.

Results: All patients were found to have sleep apnea of any degree, and 23 (72%) had severe sleep apnea. Twenty-three (72%) patients had a positive CAC score. Higher CAC scores were associated with elevated respiratory disturbance index (RDI), apnea index, oxygen desaturation index, and STOP-BANG test scores. Multivariate analysis after adjusting for potential confounding factors revealed independent relationships between the CAC score and the RDI (ß [SE] = 5.3 [2.1], p = 0.01), oxygen desaturation index (ß [SE] = 6.8 [2.8], p = 0.02), and STOP-BANG test score (ß [SE] = 90.3 [37.7], p = 0.02).

Conclusion: Our findings indicate a relationship between coronary atherosclerotic burden measured by the CAC score and the severity of sleep apnea. Performing polysomnography could be useful for investigating the severity of hidden coronary artery disease among these patients.

Sleep and Resistant Hypertension

PURPOSE OF REVIEW

The goal of the present review is to describe the current findings on the association of sleep with resistant hypertension (hypertension that remains uncontrolled despite the use of three or more antihypertensive medications from different classes, including a diuretic).

RECENT FINDINGS

Sleep disturbances, particularly obstructive sleep apnea (OSA), are highly prevalent among adults who have resistant hypertension. Randomized controlled trials indicate that treating OSA has modest effects on blood pressure lowering among those with the highest initial blood pressure. There is a paucity of research on the association of habitual sleep and other sleep disturbances with resistant hypertension. Of note, the most recent observational studies describing the association of OSA with resistant hypertension are comprised primarily of non-white race/ethnic groups who are far more likely to have resistant hypertension. OSA is associated with resistant hypertension, but there is limited data on associations between sleep characteristics and resistant hypertension. Future studies should investigate whether treating OSA can reduce disparities in resistant hypertension and whether other aspects of sleep also contribute to resistant hypertension.

Repercussion of medium and long treatment period with continuous positive airways pressure therapy in heart rate variability of obstructive sleep apnea

INTRODUCTION

Obstructive sleep apnea (OSA) is a respiratory sleep disorder. Many of these patients also exhibit autonomic alterations which can be observed through heart rate variability (HRV). Currently, one of the treatments for apnea is continuous positive airway pressure (CPAP).

OBJECTIVE

To observe OSA patients treated with CPAP exhibit HRV changes at medium and long treatment period.

METHODS

This is an integrative literature review conducted in May of 2018. The databases used for this research were PubMed, Scopus, Scielo and Pedro, the keywords used were "heart rate variability", "obstructive sleep apnea" and "CPAP". In this review was included original, published, randomized and non-randomized articles, released in the English language, before and up to April 2018, which specified the effects of CPAP therapy in autonomic dysfunction through the analysis of the HRV of patients diagnosed with OSA after at least one month of therapy.

RESULTS

The research of the literature produced 113 articles. After excluding duplicates and applying the inclusion and exclusion criteria, 8 articles were selected for this review.

CONCLUSION

It was concluded that CPAP therapy is related to change in heart rate variability in patients with obstructive sleep apnea.

Obstructive Sleep Apnea Affecting Platelet Reactivity in Patients Undergoing Percutaneous Coronary Intervention

Background:

The relationship between obstructive sleep apnea (OSA) and platelet reactivity in patients undergoing percutaneous coronary intervention (PCI) has not been defined. The present prospective, single-center study explored the relationship between platelet reactivity and OSA in patients with PCI.

Methods:

A total of 242 patients were finally included in the study. OSA was screened overnight by polysomnography. Platelet reactivity was assessed with a sequential platelet counting method, and the platelet maximum aggregation ratio (MAR) and average aggregation ratio were calculated. All patients were assigned per apnea-hypopnea index (AHI) to non-OSA (n = 128) and OSA (n = 114) groups. The receiver operating characteristic curve analysis was used to evaluate the accuracy of AHI for high platelet reactivity (HPR) on aspirin and clopidogrel, and multivariable logistic regression was used to determine the independent predictors of HPR on aspirin and clopidogrel.

Results:

Median AHI was significantly higher in the OSA group than in the non-OSA group (34.5 events/h vs. 8.1 events/h, Z = −13.422, P < 0.001). Likewise, median arachidonic acid- and adenosine diphosphate-induced maximum aggregation rate (MAR) in the OSA group was significantly higher than those in the non-OSA group (21.1% vs. 17.7%, Z = −3.525, P < 0.001 and 45.8% vs. 32.2%, Z = −5.708, P < 0.001, respectively). Multivariable logistic regression showed that OSA was the only independent predictor for HPR on aspirin (odds ratio [OR]: 1.055, 95% confidence interval [CI]: 1.033–1.077, P < 0.001) and clopidogrel (OR: 1.036, 95% CI: 1.017–1.056, P < 0.001). The cutoff value of AHI for HPR on aspirin was 45.2 events/h (sensitivity 47.1% and specificity 91.3%), whereas cutoff value of AHI for HPR on clopidogrel was 21.3 events/h (sensitivity 68.3% and specificity 67.7%).

Conclusion:

Platelet reactivity appeared to be higher in OSA patients with PCI despite having received a loading dose of aspirin and clopidogrel, and OSA might be an independent predictor of HPR on aspirin and clopidogrel.

Perioperative safety and complications in treatment of oral and maxillofacial surgery patients under general anesthesia with obstructive sleeping disorders

Patients with sleeping disorders, such as obstructive sleep apnea, (OSA) have a higher risk for postoperative complications after maxillofacial surgery under general anesthesia. The aim of this study was to detect specific complications after oral and maxillofacial surgery. Sixty-nine cases of patients with middle or severe sleep apnea who underwent an operation under general anesthesia in the oral and maxillofacial region were retrospectively analyzed. This group was compared with an age and diagnosis matched group without sleep apnea receiving the same operative treatment. We found a significant difference between the two groups concerning body mass index, the ASA-Index, the Cormack-Mallampati Index, the number of pre-existing conditions, and home medication (p < 0.05). Concerning the length of stay, overrun of estimated mean length of stay, and number of surgical complications and hypertonic events, no difference could be detected. Almost 28% of the patients with OSA in our study suffered a substantial respiratory complication even under intensive care observation. The number of patients with oxygen desaturation was 9% in the control group, which differed significantly (p = 0.0093) from the number of such patients in the OSA group. In this study, we have shown that the presence of OSA in patients undergoing elective maxillofacial surgery is associated with a considerable number of comorbidities in the postoperative period. Through preoperative OSA screening and OSA evaluation, an improvement in management of surveillance resources could be achieved and the OSA-specific risk could be assessed more precisely and also reduced.

Fasudil improves endothelial dysfunction in rats exposed to chronic intermittent hypoxia through RhoA/ROCK/NFATc3 pathway

Endothelial dysfunction is one of the main pathological changes in Obstructive sleep apnoea (OSA). The Rho kinase (ROCK) pathway is associated with endothelial dysfunction. However, the interaction between ROCK and nuclear factor of activated T cells isoform c3 (NFATc3) in the development of this pathological response under chronic intermittent hypoxia (CIH) is unclear. To simulate the OSA model, we established a moderate CIH rat model by administering the fraction of inspired O2 (FiO2) from 21% to 9%, 20 times/h, 8 h/day for 3 weeks. Fasudil (ROCK inhibitor, 8 mg/kg/d, i.p.) was administrated in the rats exposed to CIH for 3 weeks. Our results demonstrated that CIH caused significantly endothelial dysfunction, accompanying with increased ET-1 level, decreased eNOS expression and NO production, which reduced ACh-induced vascular relaxation responses. Moreover, RhoA/ROCK-2/NFATc3 expressions were up-regulated. Fasudil significantly improved CIH induced endothelial dysfunction. Data suggested that the ROCK activation is necessary for endothelial dysfunction during CIH.

SERUM LIPOPROTEIN-ASSOCIATED PHOSPHOLIPASE A2 IN MALES WITH METABOLIC SYNDROME AND OBSTRUCTIVE SLEEP APNEA

CONTEXT

Lipoprotein-associated phospholipase A2 (Lp-PLA2) is a novel biomarker for cardiovascular diseases (CVD) risk estimation with high specificity for vascular inflammation. Few studies have investigated Lp-PLA2 levels in patients with metabolic syndrome (MetS) and obstructive sleep apnea syndrome (OSAS).

OBJECTIVE

This study aimed to evaluate the role of Lp-PLA2 levels as a marker of vascular inflammation that contributes to cardiometabolic dysfunction in patients with MetS and OSAS.

DESIGN

This is a prospective case-control study.

SUBJECTS AND METHODS

83 men were enrolled. Following anthropometric measurements, laboratory analysis and overnight sleep study, patients were divided into three groups: MetS, OSAS with/without MetS. Serum Lp-PLA2 levels were determined by ELISA method.

RESULTS

Serum Lp-PLA2 levels were statistically significant among the three groups and were higher in OSAS with MetS group than those without MetS. A significant positive relationship between increased Lp-PLA2 level and CRP (C-reactive protein) and apnea-hypopnea index (AHI) was found. Average oxygen saturation (AvO2) and the lowest oxygen saturation were negatively correlated with Lp-PLA2. The number of desaturation events, oxygen desaturation index, AvO2, AHI and CRP were significant predictors of Lp-PLA2.

CONCLUSIONS

Lp-PLA2 levels are associated with OSAS severity and might play an important role in predicting CVD in OSAS with/without MetS.

High risk for obstructive sleep apnea in patients with acute myocardial infarction

OBJECTIVES

to stratify the risk for obstructive sleep apnea in patients with acute myocardial infarction, treated at a public, tertiary, teaching hospital of the state of São Paulo, Brazil, and to identify related sociodemographic and clinical factors.

METHOD

cross-sectional analytical study with 113 patients (mean age 59.57 years, 70.8% male). A specific questionnaire was used for the sociodemographic and clinical characterization and the Berlin Questionnaire for the stratification of the risk of obstructive sleep apnea syndrome.

RESULTS

the prevalence of high risk was 60.2% and the outcome of clinical worsening during hospitalization was more frequent among these patients. The factors related to high risk were body mass index over 30 kg/m2, arterial hypertension and waist circumference indicative of cardiovascular risk, while older age (60 years and over) constituted a protective factor.

CONCLUSION

considering the high prevalence of obstructive sleep apnea and its relation to clinical worsening, it is suggested that nurses should monitor, in their clinical practice, people at high risk for this syndrome, guiding control measures of modifiable factors and aiming to prevent the associated complications, including worsening of cardiovascular diseases.

Obstructive sleep apnea: Is it a biomarker of metabolic health in obesity

Context

The prevalence of obstructive sleep apnea (OSA) increases with obesity, and OSA has been linked to increased cardiovascular risk via hypoxemia and sleep disruption.

Objective and Main Outcome Measures

We hypothesized that if OSA contributes to cardio-metabolic risk, then 1) obese individuals with OSA will have more cardio-metabolic disease, and 2) patients with OSA who are non-adherent to CPAP treatment will have a greater incidence of cardio-metabolic abnormalities.

Design setting and patients

We prospectively recruited obese patients (n = 83; BMI 49 ± 9 kg/m²). All patients had polysomnography and were stratified by 1) the absence/presence of OSA, and 2) metabolic health. Detailed CPAP reports were analyzed for compliance and OSA severity in 38 subjects.

Results

OSA by polysomnography was present in 69% of patients. While 79% of patients with OSA and 54% without OSA were categorized as MAO (χ² = 5.47, p < 0.02), when adjusted for age, gender and BMI this difference was not significant (p = 0.36). Insulin levels were higher in the OSA group, but when adjusted there was no significant difference (p = 0.350). In patients on CPAP therapy, there was a negative associative trend between OSA control (apnea-hypopnea index) and beta-cell function (HOMA-β) (r = -0.406, p = 0.076), but no association between CPAP compliance and AHI with age, BMI, glucose, insulin, adiponectin, or insulin resistance.

Conclusions

OSA is not independently associated with overall cardio-metabolic health and insulin resistance in obese patients, even when accounting for treatment compliance. The strongest predictors of the obese metabolic healthy phenotype in OSA patients are age, gender and BMI.

Sleep quality and adverse outcomes for patients with acute myocardial infarction

AIMS AND OBJECTIVES

This study aimed to analyse the relationship between the worsening of clinical outcomes (cardiovascular death, recurrent cardiovascular ischaemic events and stroke) and sleep quality, daytime sleepiness and risk for obstructive sleep apnoea syndrome in patients admitted to cardiac care units due to an acute myocardial infarction.

BACKGROUND

There is evidence that sleep disorders can contribute to the worsening of cardiovascular diseases.

DESIGN

This is a descriptive study with follow-up.

METHODS

Data collection was conducted in a large university hospital in Brazil from October 2013 to March 2014. Patients admitted with acute myocardial infarction provided data about sleep quality, daytime sleepiness and risk factors for obstructive sleep apnoea syndrome by answering specific questionnaires. Clinical data were obtained from medical charts. Data were analysed with descriptive statistics and multiple logistic regression models.

RESULTS

The worsening of clinical outcome occurred in 12·4% of patients and was independently associated to poor sleep quality.

CONCLUSION

Poor sleep quality, excessive daytime sleepiness and high risk for obstructive sleep apnoea syndrome were frequent in hospitalised patients with acute myocardial infarction and affect negatively the process of recovery.

RELEVANCE TO CLINICAL PRACTICE

It is important to evaluate sleep quality and sleep disorders, aiming at preventing and reducing unfavourable outcomes of cardiovascular disease, particularly for acute myocardial infarction patients.

The chronic syndromes after previous treatment of pituitary tumours

Ultimately, almost all patients who are appropriately treated for pituitary tumours enter a chronic phase with control or cure of hormonal excess, adequate treatment of pituitary insufficiency and relief of mass effects. This phase is associated with improvement of initial signs and symptoms, but also with the persistent consequences of the initial disease and associated treatments. Pituitary insufficiency is a common denominator in many of these patients, and is associated with a reduction in quality of life, despite adequate endocrine substitution. Hypothalamic dysfunction can be present in patients previously treated for visual impairments caused by large suprasellar adenomas, or craniopharyngiomas. In addition to hypopituitarism, these patients can have multisystem morbidities caused by altered hypothalamic function, including weight gain and disturbed regulation of sleep-wake cycles. Mortality can also be affected. Patients cured of Cushing disease or acromegaly have chronic multisystem morbidities (in the case of Cushing disease, also affecting mortality) caused by irreversible effects of the previous excesses of cortisol in Cushing disease and growth hormone and insulin-like growth factor 1 in acromegaly. In addition to early diagnosis and treatment of pituitary tumours, research should focus on the amenability of these chronic post-treatment syndromes to therapeutic intervention, to improve quality of life and clinical outcomes.

Significance of vaspin in obstructive sleep apnea-hypopnea syndrome

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is a commonly-diagnosed chronic sleep disorder. It is considered to be an important independent risk factor in the development of insulin resistance (IR). Patients with OSAHS exhibit a variety of metabolic disorders, including obesity and metabolic syndrome. Visceral adipose tissue-derived serpin (vaspin) is an adipokine that is considered to be a link between obesity and IR. The present study aimed to evaluate the levels of plasma vaspin in patients with OSAHS and examine their potential correlation with sleep characteristics. A total of 20 healthy male subjects and 42 male patients with OSAHS were selected, and patients were divided into mild (n=22) and severe (n=20) OSAHS groups. The 20 patients in the severe OSAHS group received nasal continuous positive airway pressure (nCPAP) treatment for 2 months. Venous blood samples were drawn from all patients in a fasting state prior to and subsequent to nCPAP treatment, which were used to measure the levels of biochemical indicators. The sleep parameters and serologic index changes were compared prior to and following treatment. The values of contractive pressure (SBP), neck circumference (NC), waist circumference (WC), waist-to-hip ratio (WHR), body mass index (BMI) and hip circumference (HC) in the two OSAHS groups were significantly increased compared with those in the control group. In addition, the levels of vaspin in OSAHS patients were markedly increased and vaspin was revealed to be positively associated with fasting blood sugar, fasting insulin, triglycerides, homeostasis model assessment-IR, apnea-hypopnea index (AHI), NC, WC, BMI and WHR (P<0.05). After 2 months of nCPAP treatment, the SBP and AHI were significantly reduced. In conclusion, vaspin may have an important role in OSAHS patients with IR and treatment using nCPAP may improve the condition of OSAHS patients.

Non-alcoholic fatty liver disease - the heart of the matter

Non-alcoholic fatty liver disease (NAFLD) is one of the most common forms of chronic liver disease in the Western world. There is a close association with the metabolic syndrome and NAFLD is considered to be the hepatic manifestation of the metabolic syndrome. The components of the metabolic syndrome include hypertension, obesity and insulin resistance which are well established cardiovascular risk factors. The mortality rate of NAFLD patients from myocardial infarction is higher than that in the general United States population and there is also an increased risk of non-fatal cardiovascular events. This article reviews the cardiovascular complications associated with NAFLD. In order to provide comprehensive care of NAFLD patients, physicians need to be aware of, and search for, the cardiac morbidity associated with NAFLD.

The role of continuous positive airway pressure in blood pressure control for patients with obstructive sleep apnea and hypertension: a meta-analysis of randomized controlled trials

The aim of this study was to review the effect of continuous positive airway pressure (CPAP) on blood pressure (BP) in patients with obstructive sleep apnea (OSA) and hypertension. Biomedical databases were searched for randomized controlled trials (RCTs) comparing CPAP with control among these patients. Seven RCTs reporting 24-hour ambulatory BP were identified for meta-analysis. CPAP was associated with significant reductions in 24-hour ambulatory systolic blood pressure (SBP) (-2.32 mm Hg; 95% confidence interval [CI], -3.65 to -1.00) and diastolic blood pressure (DBP) (-1.98 mm Hg; 95% CI, -2.82 to -1.14). CPAP led to more significant improvement in nocturnal SBP than that in diurnal SBP. Subgroup analysis showed that patients with resistant hypertension or receiving antihypertensive drugs benefited most from CPAP. Meta-regression indicated that CPAP compliance, age, and baseline SBP were positively correlated with decrease in 24-hour DBP, but not reduction in 24-hour SBP.

Association of Fragmented QRS with Subclinical Left Ventricular Dysfunction in Patients with Obstructive Sleep Apnea

OBJECTIVE

We aimed to investigate whether fragmented QRS (fQRS) is associated with subclinical left ventricular (LV) dysfunction in patients with obstructive sleep apnea (OSA).

SUBJECTS AND METHODS

A total of 141 patients with OSA who had normal LV ejection fraction (LVEF) were included in the study. The fQRS was defined as the presence of an additional R wave, notching of R or S wave or the presence of fragmentation in 2 contiguous electrocardiography (ECG) leads. Subclinical LV dysfunction was defined as the presence of a tissue Doppler-derived Tei index of ≥ 0.5 in the absence of impaired LVEF (<50%) as assessed by transthoracic echocardiography.

RESULTS

Of the 141 patients, 71 (50.4%) had subclinical LV dysfunction. Overall, the prevalence of the fQRS was 61% (86/141). Patients with fQRS had significantly higher Tei indices than those without fQRS [median 0.66, interquartile range (IQR) 0.39 vs. median 0.40, IQR 0.15, p < 0.001]. The presence of fQRS on ECG predicted subclinical LV dysfunction in univariate logistic regression analysis [odds ratio (OR) 6.69, 95% confidence interval (CI) 3.10-14.43]. The association remained significant after adjusting for all potential confounders (OR 4.59, 95% CI 1.94-10.87).

CONCLUSION

fQRS on ECG was an independent predictor of subclinical LV dysfunction in patients with OSA. This simple tool might help to identify OSA patients who could be at risk for developing overt cardiac dysfunction.

Severity of Childhood Obstructive Sleep Apnea and Hypertension Improved after Adenotonsillectomy

Objective

To report improvements in childhood obstructive sleep apnea (OSA) and hypertension after adenotonsillectomy.

Study Design

Case series with planned data collection.

Setting

Tertiary referral center.

Subjects and Methods

Fifty consecutive patients (36 boys and 14 girls; median age, 7.0 years) who underwent plasma knife–assisted total tonsillectomy and adenoidectomy for OSA between January 2010 and March 2013 were assessed with the body mass index z score, apnea-hypopnea index (AHI), systolic blood pressure (BP), and diastolic BP at baseline and at ≥6 months postoperatively. Changes in these parameters were statistically analyzed using nonparametric tests with the bootstrap approach.

Results

The median follow-up period was 9.6 months. Postoperatively, the median AHI significantly reduced from 9.8 to 1.6 ( P < .001). Although the median systolic BP and diastolic BP insignificantly changed in the overall group, both were significantly reduced in children with preoperative hypertension (systolic: from 119.0 to 113.0 [ P = .038]; diastolic: from 79.0 to 68.0 [ P = .005]). Accordingly, the hypertension rate significantly reduced from 34% to 14% ( P = .006). However, the change in OSA severity was not well correlated with the change in hypertension severity. In multiple logistic regression analysis with forward selection, a combination of preoperative hypertension and severe OSA was a significant predictor of postoperative hypertension (relative risk, 15.4; 95% confidence interval, 3.7-64.3; P < .001).

Conclusion

The decreased hypertension rate indicates that a reduction of the AHI is not all that matters after adenotonsillectomy in childhood OSA. However, patients with preoperative severe OSA and hypertension need careful management of their elevated BP despite surgical treatment.

Nonalcoholic fatty liver disease and vascular disease: State-of-the-art

Nonalcoholic fatty liver disease (NAFLD), the most common of chronic liver disease in Western Country, is closely related to insulin resistance and oxidative stress and includes a wide spectrum of liver diseases ranging from steatosis alone, usually a benign and non-progressive condition, to nonalcoholic steatohepatitis (NASH), which may progress to liver fibrosis and cirrhosis. NAFLD is considered the hepatic manifestation of the metabolic syndrome with which shares several characteristics, however recent data suggest that NAFLD is linked to increased cardiovascular risk independently of the broad spectrum of risk factors of metabolic syndrome. Accumulating evidence suggests that the clinical burden of NAFLD is not restricted to liver-related morbidity and mortality, with the majority of deaths in NAFLD patients related to cardiovascular disease and cancer and not to the progression of liver disease. Retrospective and prospective studies provide evidence of a strong association between NAFLD and subclinical manifestation of atherosclerosis (increased intima-media thickness, endothelial dysfunction, arterial stiffness, impaired left ventricular function and coronary calcification). A general agreement emerging from these studies indicates that patients with NASH are at higher risk of cardiovascular diseases than those with simple steatosis, emphasizing the role of chronic inflammation in the pathogenesis of atherosclerosis of these patients. It is very likely that the different mechanisms involved in the pathogenesis of atherosclerosis in patients with NAFLD have a different relevance in the patients according to individual genetic background. In conclusion, in the presence of NAFLD patients should undergo a complete cardiovascular evaluation to prevent future atherosclerotic complications. Specific life-style modification and aggressive pharmaceutical modification will not only reduce the progression of liver disease, but also reduce morbidity for cardiovascular disease improving overall prognosis and survival.

Relationship of redundant Th17 cells and IL-17A, but not IL-17 F, with the severity of obstructive sleep apnoea/hypopnoea syndrome (OSAHS)

Background

The pathogenesis of obstructive sleep apnoea/hypopnoea syndrome (OSAHS), a highly prevalent disease, is not completely understood. The purpose of this study was to investigate the contributions of Th17 cells and the Th17-associated cytokines IL-17A and IL-17 F to OSAHS.

Methods

46 male patients with a clinical suspicion of OSAHS were enrolled and divided into four groups based on their polysomnography results: controls and mild, moderate, and severe OSAHS. The serum levels of IL-17A and IL-17 F were determined by enzyme linked immunosorbent assay (ELISA), pulmonary arterial pressure (PAP) was determined by echocardiography, and Th17 cell frequencies in peripheral blood were measured by flow cytometry.

Results

Serum IL-17A levels in the severe group were elevated (median value: control group 0.89 pg/ml, mild OSAHS 1.02 pg/ml, moderate OSAHS 1.18 pg/ml, and severe OSAHS 1.62 pg/ml; p < 0.05) and positively correlated with AHI (r = 0.52, p < 0.05) but negatively related to the mean O₂ saturation and lowest O₂ saturation (r = −0.349, p < 0.05; and r = −0.336, p < 0.05, respectively). Although the frequencies of Th17 cells in the OSAHS groups were higher than that in the control group, these differences were not significant (p = 0.275). Pulmonary arterial hypertension was not present in our patients as the median PAP of the normal control and the mild, moderate, and severe OSAHS groups were 26, 27.5, 24.5, and 25.5 mmHg, respectively (p = 0.676).

Conclusion

IL-17A may be involved in the pathogenesis of OSAHS and may represent a target for therapeutic intervention.

Early left ventricular systolic and diastolic dysfunction in patients with newly diagnosed obstructive sleep apnoea and normal left ventricular ejection fraction

The aim of the study was to evaluate whether obstructive sleep apnea (OSA) contributes directly to left ventricular (LV) diastolic and regional systolic dysfunction in newly diagnosed OSA with normal left ventricle ejection fraction. Methods. 125 consecutive patients were prospectively enrolled in the study. Control group consisted of 78 asymptomatic age-matched healthy subjects who did not have any cardiovascular and respiratory diseases. All patients had undergone overnight polysomnography and standard transthoracic and tissue Doppler imaging echocardiogram. Results. The E/A ratio and the peak E wave at mitral flow were significantly lower and the peak A wave at mitral flow was significantly higher in OSA patients compared with control subjects. Left ventricle isovolumetric relaxation time (IVRT) and mitral valve flow propagation (MVFP) were significantly longer in OSA patients than in controls. Tissue Doppler derived S′ amplitude of lateral part at mitral valve (S′Lm) and E′ wave amplitudes both at the lateral (E′Lm) and septal parts of the mitral valve (E′Sm) were significantly lower in OSA patients compared to controls. Conclusion. Newly diagnosed OSA patients with normal global LV function have significantly impaired diastolic function and regional longitudinal systolic function. OSA is independently associated with these changes in LV function.

Impact of sleep-disordered breathing treatment on upper airway anatomy and physiology

Sleep-disordered breathing (SDB) is a major public health problem. Various anatomic, pathophysiologic, and environmental changes contribute to SDB. The successful treatment of SDB reverses many of these abnormal processes. The present article discusses the current clinical evidence that supports the reversibility and its potential application in the management of SDB. Continuous positive airway pressure reduces angiogenesis and inflammatory edema, increases pharyngeal size, and improves surrogate markers of vascular inflammation and tongue muscle fiber types. Mandibular advancement devices lead to favorable maxillary and mandibular changes, increase pharyngeal area, and improve hypertension. Uvulopalatopharyngoplasty increases posterior airway space and pharyngeal volume, reduces nasal and oral resistance, and lowers response to high CO2. Weight loss reduces nasopharyngeal collapsibility, critical closing pressure of the airway, apnea-hypopnea index, and improves oxygen saturations. Potential clinical benefits of these changes in the management of SDB and patient compliance with treatment are discussed.