Obstructive sleep apnea is associated with increased arterial stiffness in severe obesity

Research Progress and Clinical Value of Subendocardial Viability Ratio

Cardiovascular disease remains the leading cause of morbidity and mortality worldwide, with ischemic heart disease being a major contributor, either through coronary atherosclerotic plaque-related major vascular disease or coronary microvascular dysfunction. Obstruction of coronary blood flow impairs myocardial perfusion, which may lead to acute myocardial infarction in severe cases. The subendocardial viability ratio, also known as the Buckberg index, is a valuable tool for evaluation of myocardial perfusion because it reflects the balance between myocardial oxygen supply and oxygen demand. The subendocardial viability ratio can effectively evaluate the function of the coronary microcirculation and is associated with arterial stiffness. This ratio also has potential value in predicting adverse cardiovascular events and mortality in various populations. Moreover, the subendocardial viability ratio has demonstrated clinical significance in a range of diseases, including hypertension, aortic stenosis, peripheral arterial disease, chronic kidney disease, diabetes, and rheumatoid arthritis. This review summarizes the applications of the subendocardial viability ratio, its particular progress in the relevant research, and its clinical significance in cardiovascular diseases.

Incremental values of AOPP, IL-6, and GDF15 for identifying arteriosclerosis in patients with obstructive sleep apnea

BACKGROUND

The objective of this study was to determine the independent and incremental values of advanced oxidative protein product (AOPP), interleukin 6 (IL-6), and growth differentiation factor 15 (GDF15) in identifying arteriosclerosis in patients with obstructive sleep apnea (OSA).

METHODS

A total of 104 individuals diagnosed with OSA by polysomnography were recruited in our study. Arteriosclerosis was defined by measuring the ultrafast pulse wave velocity of the carotid artery. Peripheral venous blood samples were collected to analyze the levels of AOPP, IL-6, and GDF15 utilizing commercially available enzyme-linked immunosorbent assays.

RESULTS

Compared to OSA patients without arteriosclerosis, those with arteriosclerosis exhibited significantly higher levels of AOPP, IL-6, and GDF15. GDF15 remained significantly associated with arteriosclerosis even after accounting for clinical factors such as age, gender, body mass index, systolic blood pressure, fasting blood glucose, smoking, and the apnea-hypoxia index (AHI). GDF15 demonstrated the largest area under the curve (AUC) for identifying arteriosclerosis in OSA patients (AUC, 0.85 [0.77-0.94]). The logistic regression model, combining clinical factors and AHI, was enhanced by the inclusion of AOPP and IL-6 (Chi-square = 25.06), and even further improved when GDF15 was added (Chi-square = 50.74). The integrated discrimination index increased by 0.06 to 0.16 when GDF15 was added to the models including clinical factors, AOPP, and IL-6.

CONCLUSIONS

This study verified the independent and incremental value of GDF15 in identifying arteriosclerosis in OSA patients, surpassing clinical risk factors and other serum biomarkers such as AOPP and IL-6.

The Association of Obstructive Sleep Apnea in Ischemia with No Obstructive Coronary Artery Disease - A Pilot Study

Obstructive sleep apnea (OSA) is increasingly recognized to be a risk factor for cardiovascular disease. This pilot study assessed the association of OSA and invasive coronary microvascular function in patients with ischemia with no obstructive coronary artery disease (INOCA). Forty-two patients with angina, were prospectively screened at a single tertiary centre covering the northern metropolitan area of South Australia, from February 2018 to December 2020 (ACTRN12618000149268). Forty patients were invited into to this observational study after coronary angiography demonstrated INOCA and functional coronary vasomotor disorder (n = 40). Twenty one participants subsequently underwent a sleep study for OSA diagnosis while 9 participants had prior formal diagnosis of OSA (ACTRN12618000227291). Of the 30 participants with OSA data, 87% (n = 26) had a diagnosis of OSA. Accordingly, 11 with mild severity, 7 with moderate severity and 8 with severe OSA. No OSA was observed in 4 participants. Participants with OSA were older [61.4±8.7 vs 49.9±9.7, P = 0.002] with similar clinical characteristics for the pattern and severity of angina and other co-morbidities. 73.3% (n = 22) had abnormal functional disorders of the epicardial coronary arteries and/or coronary microcirculation. On multivariate analysis, OSA was the only statistically significant association with functional coronary microvascular disorders [OR 53.95, 1.41 -2065.01, P = 0.032]. This study provided an observation of a significant correlation between INOCA with abnormal coronary vasomotor function and OSA in an Australian cohort. This correlation supports a possible pathophysiological interplay between these two conditions that needs to be further evaluated. The benefit of treatment of OSA in this subset remains unknown.

Obstructive Sleep Apnea in Coronary Artery Disease

Obstructive sleep apnea (OSA) is a common sleep-related breathing disorder, characterised by obstruction of upper airways during sleep, resulting in repetitive breathing pauses accompanied by oxygen desaturation and arousal from sleep. OSA patients commonly suffers from poor sleep quality and reduced quality of life. Further, OSA is associated with cardiovascular risk factors and linked independently to both structural coronary artery disease (CAD) as well as functional CAD. Structural CAD is depicted by atherosclerosis (either obstructive or non-obstructive) of the epicardial coronary arteries, while functional CAD, encompasses the spectrum of coronary vasomotor disorders (CVD). There are multiple factors including intermittent hypoxia (IH), sleep fragmentation, and intra-thoracic pressure swings leading to altered cardiopulmonary vascular hemodynamic. IH and its downstream maladaptive responses has the most robust evidence for OSA's role in atherogenesis. CPAP therapy has been linked with reduction in major adverse cardiovascular events in meta-analyses, however, pivotal randomised controlled trials failed to demonstrate its significance.

Metabolic dysfunction in OSA: Is there something new under the sun?

The growing number of patients with obstructive sleep apnea is challenging healthcare systems worldwide. Obstructive sleep apnea is characterized by chronic intermittent hypoxaemia, episodes of apnea and hypopnea, and fragmented sleep. Cardiovascular and metabolic diseases are common in obstructive sleep apnea, also in lean patients. Further, comorbidity burden is not unambiguously linked to the severity of obstructive sleep apnea. There is a growing body of evidence revealing diverse functions beyond the conventional tasks of different organs such as carotid body and gut microbiota. Chronic intermittent hypoxia and sleep loss due to sleep fragmentation are associated with insulin resistance. Indeed, carotid body is a multi-sensor organ not sensoring only hypoxia and hypercapnia but also acting as a metabolic sensor. The emerging evidence shows that obstructive sleep apnea and particularly chronic intermittent hypoxia is associated with non-alcoholic fatty liver disease. Gut dysbiosis seems to be an important factor in the pathophysiology of obstructive sleep apnea and its consequences. The impact of sleep fragmentation and intermittent hypoxia on the development of metabolic syndrome may be mediated via altered gut microbiota. Circadian misalignment seems to have an impact on the cardiometabolic risk in obstructive sleep apnea. Dysfunction of cerebral metabolism is also related to hypoxia and sleep fragmentation. Therefore, obstructive sleep apnea may alter cerebral metabolism and predispose to neurocognitive impairment. Moreover, recent data show that obstructive sleep apnea independently predicts impaired lipid levels. This mini-review will provide novel insights into the mechanisms of metabolic dysfunction in obstructive sleep apnea combining recent evidence from basic, translational and clinical research, and discuss the impact of positive airway pressure treatment on metabolic disorders.

Predictors of Obstructive Sleep Apnoea (OSA) Population in the Coronary Angiogram Database of South Australia (CADOSA)

Obstructive sleep apnoea (OSA) is increasingly recognized to be a risk factor for cardiovascular disease. This study assessed the prevalence and clinical predictors of OSA in patients undergoing coronary angiography. Consecutive patients undergoing coronary angiography in South Australian public hospitals from 2015 to 2018 were included. Clinical details for consecutive patients undergoing coronary angiography in South Australian public hospitals were captured by the Coronary Angiogram Database of South Australia (CADOSA) registry staff, with OSA identified by patient report. Among the 9,885 patients undergoing coronary angiography for the investigation of chest pain, 11% (n = 1,089) were documented as having OSA. Independent clinical predictors of OSA included male gender (OR 2.22, 1.86-2.65, P < 0.001), diabetes mellitus (OR 1.84, 1.58-2.14, P < 0.001), depression (OR 1.81, 1.55-2.12, P < 0.001), prior heart failure (OR 1.63, 1.22-2.18, P = 0.001), hypertension (OR 1.61, 1.32-1.95, P ≤ 0.001), asthma (OR 1.61, 1.34-1.93, P < 0.001), not a current smoker (OR 1.60, 1.30-1.96, P < 0.001), dyslipidaemia (OR 1.46, 1.22-1.76, P < 0.001), non-acute coronary syndrome presentation (OR 1.45, 1.25-1.69, P < 0.001), chronic lung disease (OR 1.40, 1.12-1.73, P = 0.003), cerebrovascular disease (OR 1.36, 1.07-1.73, P = 0.012), non-obstructive coronary artery disease (NOCAD) (OR 1.30, 1.10-1.55, P = 0.003) and atrial fibrillation/flutter (OR 1.30, 1.06-1.60, P = 0.012). Finally, stable angina (32.1% vs 22.7%) and NOCAD (29.1% vs 26.3%, P = 0.051) were trended more common in patients with OSA versus no OSA. In addition to established risk factors for OSA, this study found NOCAD to be independent predictor of OSA; especially in those presenting with a stable angina presentation. This suggests that coronary vasomotor disorders may be associated with OSA, although further detailed studies are required.

Telemedicine for Continuous Positive Airway Pressure in Sleep Apnea. A Randomized, Controlled Study

Rationale: Continuous positive airway pressure (CPAP) is the standard treatment for the obstructive sleep apnea syndrome (OSAS), but long-term adherence remains a challenge. In a pilot study, we observed that telemedicine combined with telemetrically triggered interventions was associated with improved CPAP adherence in the first month of treatment.Objectives: In the current randomized, controlled phase III trial, we aimed to collect pivotal data for the use of telemedicine in CPAP treatment of patients with OSAS.Methods: Symptomatic patients with OSAS were randomized to a telemedicine or control arm and initiated CPAP treatment. Phone calls were triggered in the telemedicine group during the first month of treatment upon either poor use or excessive mask leakage. Patients were followed for 6 months. Measures of CPAP use at 6 months were the main study endpoints.Results: Among 240 patients enrolled, 71 (30%) discontinued CPAP treatment over the course of the study. The primary outcome measure, the proportion of nights with CPAP use greater than 1 hour, was not statistically different in the telemedicine group (92.0%) versus the control group (88.2%) (P = 0.565). The daily hours of CPAP use at 6 months also did not differ significantly between the telemedicine group (5.6 h) and the control group (4.8 h) (P = 0.663). However, in a post hoc analysis, telemedicine led to increased device use in a subgroup of patients with a mild form of disease (5.6 h vs. 3.4 h; P = 0.026). The telemedicine-based intervention had a positive impact on sleep-related quality of life as measured with the Quebec Sleep Questionnaire (5.55 vs. 5.49 at 1 mo [P = 0.020]; 5.61 vs. 5.46 at 6 mo [P = 0.013]).Conclusions: A telemetrically triggered intervention in the first month of treatment did not improve CPAP use in the study population overall, but it had positive effects in patients with a mild form of OSAS and led to an improvement in sleep-related quality of life.Clinical trial registered with www.clinicaltrials.gov (NCT01715194).

Hospital outcomes in non-surgical patients identified at risk for OSA

BACKGROUND

In-hospital respiratory outcomes of non-surgical patients with undiagnosed obstructive sleep apnea (OSA), particularly those with significant comorbidities are not well defined. Undiagnosed and untreated OSA may be associated with increased cardiopulmonary morbidity.

STUDY OBJECTIVES

Evaluate respiratory failure outcomes in patients identified as at-risk for OSA by the Berlin Questionnaire (BQ).

METHODS

This was a retrospective study conducted using electronic health records at a large health system. The BQ was administered at admission to screen for OSA to medical-service patients under the age of 80 years old meeting the following health system criteria: (1) BMI greater than 30; (2) any of the following comorbid diagnoses: hypertension, heart failure, acute coronary syndrome, pulmonary hypertension, arrhythmia, cerebrovascular event/stroke, or diabetes. Patients with known OSA or undergoing surgery were excluded. Patients were classified as high-risk or low-risk for OSA based on the BQ score as follows: low-risk (0 or 1 category with a positive score on the BQ); high-risk (2 or more categories with a positive score on BQ). The primary outcome was respiratory failure during index hospital stay defined by any of the following: orders for conventional ventilation or intubation; at least two instances of oxygen saturation less than 88% by pulse oximetry; at least two instances of respiratory rate over 30 breaths per minute; and any orders placed for non-invasive mechanical ventilation without a previous diagnosis of sleep apnea. Propensity scores were used to control for patient characteristics.

RESULTS

Records of 15,253 patients were assessed. There were no significant differences in the composite outcome of respiratory failure by risk of OSA (high risk: 11%, low risk: 10%, p = 0.55). When respiratory failure was defined as need for ventilation, more patients in the low-risk group experienced invasive mechanical ventilation (high-risk: 1.8% vs. low-risk: 2.3%, p = 0.041). Mortality was decreased in patients at high-risk for OSA (0.86%) vs. low risk for OSA (1.53%, p < 0.001).

CONCLUSIONS

Further prospective studies are needed to understand the contribution of undiagnosed OSA to in-hospital respiratory outcomes.

Associations Between Obstructive Sleep Apnea and Measures of Arterial Stiffness

STUDY OBJECTIVES

The aim of this study was to determine whether severity measures of obstructive sleep apnea (OSA) are associated with arterial stiffness and central blood pressure (two important cardiovascular risk factors) in a large group of patients with OSA.

METHODS

Baseline data from six studies on OSA in which arterial stiffness and central aortic blood pressure measures were determined using applanation tonometry were pooled. Associations between measures of arterial stiffness (heart rate corrected augmentation index [AI75]), central aortic blood pressure (central systolic pressure [CSP] and heart rate corrected central augmentation pressure [CAP75]) and measures of OSA severity were explored using stepwise regression modelling.

RESULTS

Data from 362 participants (M:F ratio 13:1) with mean (standard deviation) age 49.2 (11.0) years, body mass index 31.9 (5.3) kg/m², apnea-hypopnea index (AHI) 35.7 (20.7) events/h were included in the analyses. The AHI, oxygen desaturation index (ODI3%), and sleep time with SpO₂ < 90% (T90) were all associated with arterial stiffness (AI75), (AHI: adj. β = .069; P = .01; ODI3%: adj. β = .072; P = .01; T90: adj. β = .18; P < .0001) and CAP75 (AHI: adj. β = .030; P = .01; ODI3%: adj. β = .027; P = .02; T90: adj. β = .080; P < .0001). AHI was also associated with CSP (AHI: adj. β = .11; P = .002).

CONCLUSIONS

OSA severity was significantly associated with augmentation index and CAP75 although the relationships were not strong.

Contribution of obstructive sleep apnoea to arterial stiffness: a meta-analysis using individual patient data

BACKGROUND

Arterial stiffness, measured by pulse wave velocity (PWV), is a strong independent predictor of late cardiovascular events and mortality. It is recognised that obstructive sleep apnoea (OSA) is associated with cardiovascular comorbidities and mortality. Although previous meta-analyses concluded that PWV is elevated in OSA, we feel that an individual patient data analysis from nine relatively homogeneous studies could help answer: to what extent does OSA drive arterial stiffness?

METHODS

Individual data from well-characterised patients referred for suspicion of OSA, included in nine studies in which carotid-femoral PWV was measured using a Complior device, were merged for an individual patient data meta-analysis.

RESULTS

893 subjects were included (age: 56±11 (mean±SD), 72% men, 84% with confirmed OSA). Body Mass Index varied from 15 to 81 kg/m² (30±7 kg/m²). PWV ranged from 5.3 to 20.5 m/s (10.4±2.3 m/s). In univariate analysis, log(PWV) was strongly related to age, gender, systolic blood pressure, presence of type 2 diabetes (all p<0.01) as well as to dyslipidaemia (p=0.03) and an Epworth Sleepiness Scale score ≥9 (p=0.04), whereas it was not related to obesity (p=0.54), a severe Apnoea-Hypopnoea Index (p=0.14), mean nocturnal saturation (p=0.33) or sleep time with oxygen saturation below 90% (p=0.47). In multivariable analysis, PWV was independently associated with age, systolic blood pressure and diabetes (all p<0.01), whereas severe OSA was not significantly associated with PWV.

CONCLUSION

Our individual patient meta-analysis showed that elevated arterial stiffness in patients with OSA is driven by conventional cardiovascular risk factors rather than apnoea parameters.

Obstructive sleep apnoea is associated with progression of arterial stiffness independent of obesity in participants without hypertension: A KoGES Prospective Cohort Study

Accumulating evidence shows that obstructive sleep apnoea (OSA) is associated with an increased risk of cardiovascular disease. However, there are no published prospective studies on the relationship between OSA and the progression of arterial stiffness. We hypothesised that OSA would increase the risk of arterial stiffness progression, independent of obesity. In the present large cohort study, 1921 participants were randomly selected and underwent polysomnography. The brachial ankle pulse wave velocity (baPWV) was measured at baseline and during the follow-period using a standard protocol. Elevated baPWV was defined as a value greater than the cut-off of highest tertile level in the complete study cohort. The percentage of elevated baPWV and the ΔbaPWV significantly increased with OSA severity. After adjusting for potential confounding factors, participants with moderate-to-severe OSA without hypertension had a significantly higher risk of elevated ΔbaPWV than those without OSA. More importantly, using multivariate mixed-effect models, we found that the ΔbaPWV over 6 years significantly differed according to OSA severity. Therefore, moderate-to-severe OSA in participants without hypertension was a predictor of future burden of arterial stiffness progression, independent of obesity, suggesting that it may contribute to the increased risk of cardiovascular disease.

Impairment of vascular strain in patients with obstructive sleep apnea

Background

Obstructive sleep apnea (OSA) is an independent risk factor for the development of cardiovascular diseases. Aim of this present study was to evaluate and extend recent research on the influence of obstructive sleep apnea on vascular strain.

Methods

A total number of 98 patients were integrated in the study. Patients were grouped according to the Apnea-Hypopnea-Index (AHI) in patients with mild-to-moderate OSA (5/h ≤ AHI < 30/h), severe OSA (AHI ≥ 30/h) and controls (AHI < 5/h). Groups were matched in age, body-mass-index and cardiovascular risks. Vascular strain of common carotid arteries was assessed by ultrasound speckle-tracking. A minor group of 30 patients and controls further underwent assessment of vascular strain of brachial and femoral arteries. Additionally, all patients underwent blood testing to reveal potential influences of inflammatory markers on arterial stiffness. In additional analysis we examined the effect of statin therapy on vascular strain.

Results

Patients with OSA showed significantly reduced values of vascular strain of common carotid arteries. Radial and circumferential strains were significantly lower in both patients with mild-to-moderate (p = .05) and patients with severe OSA (p = .001) compared to control. Vascular strain parameters of brachial and femoral arteries showed no consistent results. There were no significant correlations of inflammatory markers with vascular strain parameters. No significant differences in vascular strain were detected between statin and non-statin groups.

Conclusion

Patients with OSA show significantly reduced vascular strain assessed by ultrasound-based speckle-tracking. Vascular stiffness increases with the severity of the disease. Target vessels to assess vascular strain in patients with OSA are common carotid arteries, whereas other sites of the arterial tree are not reliable. No significant impact of current statin therapy on vascular strain was found. Further studies are needed to evaluate potential benefit of statins in secondary prevention of atherosclerosis in OSA.

Recognition of Sleep Apnea Is Increasing. Analysis of Trends in Two Large, Representative Databases of Outpatient Practice

RATIONALE

Little is known about recent trends in physician reporting of sleep apnea during outpatient practice visits.

OBJECTIVES

To assess trends in the frequency of adult outpatient visits for sleep apnea in the United States, the clinicians who provided those visits, and the characteristics of patients reported to have sleep apnea; and to assess whether the reporting of a diagnosis of sleep apnea varies across regions of the country as a function of body weight and insurance status.

METHODS

We reviewed annual stratified samples of patients identified as having sleep apnea during physician office visits in the U.S. National Ambulatory Medical Care Survey database, and during visits to hospital outpatient practices in the U.S. National Hospital Ambulatory Medical Care Survey database, between 1993 and 2010. The aggregate data set included records of 838,000 ambulatory practice visits.

MEASUREMENTS AND MAIN RESULTS

During this 17-year period, survey reports of a diagnosis of sleep apnea increased 14.6- fold, from 420,000 to 6.37 million per year (P = 0.0002). Thirty-three percent were reported by primary care providers, 17% by pulmonologists, and 10% by otolaryngologists. Over the period of observation, reports of a diagnosis of sleep apnea by "other groups" increased considerably (P < 0.001). The per capita rate of sleep apnea diagnoses per 1,000 persons per year differed across regions of the United States (P < 0.0001). Regions that reported a higher rate of sleep apnea appeared to be influenced by obesity (P < 0.001) and health insurance status (P < 0.005).

CONCLUSIONS

Diagnoses of sleep apnea during outpatient visits to hospital-based and non-hospital-based practices in the United States were much more frequent in 2010 than in 1993, as reported by outpatient practice clinicians participating in national surveys. Although the majority of diagnoses of sleep apnea were reported by primary care providers, pulmonologists, and otolaryngologists (60%), there was a substantial increase in reports of sleep apnea by clinicians practicing other specialties during the study period. Reporting of a diagnosis of sleep apnea varied by obesity prevalence and health insurance status across U.S. geographic regions.

Effect of CPAP, Weight Loss, or CPAP Plus Weight Loss on Central Hemodynamics and Arterial Stiffness

Obesity and obstructive sleep apnea tend to coexist. Little is known about the effects of obstructive sleep apnea, obesity, or their treatment on central aortic pressures and large artery stiffness. We randomized 139 adults with obesity (body mass index >30 kg/m2) and moderate-to-severe obstructive sleep apnea to (1) continuous positive airway pressure (CPAP) therapy (n=45), (2) weight loss (WL) therapy (n=48), or (3) combined CPAP and WL (n=46) for 24 weeks. We assessed the effect of these interventions on central pressures and carotid-femoral pulse wave velocity (a measure of large artery stiffness), measured with arterial tonometry. Central systolic pressure was reduced significantly only in the combination arm (-7.4 mm Hg; 95% confidence interval, -12.5 to -2.4 mm Hg; P=0.004), without significant reductions detected in either the WL-only (-2.3 mm Hg; 95% confidence interval, -7.5 to 3.0; P=0.39) or the CPAP-only (-3.1 mm Hg; 95% confidence interval, -8.3 to 2.0; P=0.23) arms. However, none of these interventions significantly changed central pulse pressure, pulse pressure amplification, or the central augmentation index. The change in mean arterial pressure (P=0.008) and heart rate (P=0.027) induced by the interventions was significant predictors of the change in carotid-femoral pulse wave velocity. However, after adjustment for mean arterial pressure and heart rate, no significant changes in carotid-femoral pulse wave velocity were observed in any group. In obese subjects with obstructive sleep apnea, combination therapy with WL and CPAP is effective in reducing central systolic pressure. However, this effect is largely mediated by changes in mean, rather than central pulse pressure. WL and CPAP, alone or in combination, did not reduce large artery stiffness in this population.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00371293.

Review of and Updates on Hypertension in Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a prevalent sleep disorder as is hypertension (HTN) in the 21st century with the rising incidence of obesity. Numerous studies have shown a strong association of OSA with cardiovascular morbidity and mortality. There is overwhelming evidence supporting the relationship between OSA and hypertension (HTN). The pathophysiology of HTN in OSA is complex and dependent on various factors such as sympathetic tone, renin-angiotensin-aldosterone system, endothelial dysfunction, and altered baroreceptor reflexes. The treatment of OSA is multifactorial ranging from CPAP to oral appliances to lifestyle modifications to antihypertensive drugs. OSA and HTN both need prompt diagnosis and treatment to help address the growing cardiovascular morbidity and mortality due to these two entities.

Role of sleep quality in the metabolic syndrome

Emerging evidence has assigned an important role to sleep as a modulator of metabolic homeostasis. The impact of variations in sleep duration, sleep-disordered breathing, and chronotype to cardiometabolic function encompasses a wide array of perturbations spanning from obesity, insulin resistance, type 2 diabetes, the metabolic syndrome, and cardiovascular disease risk and mortality in both adults and children. Here, we critically and extensively review the published literature on such important issues and provide a comprehensive overview of the most salient pathophysiologic pathways underlying the links between sleep, sleep disorders, and cardiometabolic functioning.

The Frequency and Energy of Snoring Sounds Are Associated with Common Carotid Artery Intima-Media Thickness in Obstructive Sleep Apnea Patients

Obstructive sleep apnea (OSA) is a known risk factor for atherosclerosis. We investigated the association of common carotid artery intima-media thickness (CCA-IMT) with snoring sounds in OSA patients. A total of 30 newly diagnosed OSA patients with no history of cardiovascular diseases were prospectively enrolled for measuring mean CCA-IMT with B-mode ultrasonography, body mass index, metabolic syndrome, 10-year cardiovascular disease risk score, high-sensitivity C-reactive protein, and homocysteine. Good-quality signals of full-night snoring sounds in an ordinary sleep condition obtained from 15 participants were further acoustically analyzed (Included group). All variables of interest were not significantly different (all p > 0.05) between the included and non-included groups except for diastolic blood pressure (p = 0.037). In the included group, CCA-IMT was significantly correlated with snoring sound energies of 0–20 Hz (r = 0.608, p = 0.036) and 652–1500 Hz (r = 0.632, p = 0.027) and was not significantly associated with that of 20–652 Hz (r = 0.366, p = 0.242) after adjustment for age and sex. Our findings suggest that underlying snoring sounds may cause carotid wall thickening and support the large-scale evaluation of snoring sound characters as markers of surveillance and for risk stratification at diagnosis.

Beyond type 2 diabetes, obesity and hypertension: an axis including sleep apnea, left ventricular hypertrophy, endothelial dysfunction, and aortic stiffness among Mexican Americans in Starr County, Texas

BACKGROUND

There is an increasing appreciation for a series of less traditional risk factors that should not be ignored when considering type 2 diabetes, obesity, hypertension, and cardiovascular disease. These include aortic stiffness, cardiac structure, impaired endothelial function and obstructive sleep apnea. They are associated to varying degrees with each disease categorization and with each other. It is not clear whether they represent additional complications, concomitants or antecedents of disease. Starr County, Texas, with its predominantly Mexican American population has been shown previously to bear a disproportionate burden of the major disease categories, but little is known about the distribution of these less traditional factors.

METHODS

Type 2 diabetes, obesity and hypertension frequencies were determined through a systematic survey of Starr County conducted from 2002 to 2006. Individuals from this examination and an enriched set with type 2 diabetes were re-examined from 2010 to 2014 including assessment of cardiac structure, sleep apnea, endothelial function and aortic stiffness. Individual and combined frequencies of these inter-related (i.e., axis) conditions were estimated and associations evaluated.

RESULTS

Household screening of 5230 individuals aged 20 years and above followed by direct physical assessment of 1610 identified 23.7 % of men and 26.7 % of women with type 2 diabetes, 46.2 and 49.5 % of men and women, respectively with obesity and 32.1 and 32.4 % with hypertension. Evaluation of pulse wave velocity, left ventricular mass, endothelial function and sleep apnea identified 22.3, 12.7, 48.6 and 45.2 % of men as having "at risk" values for each condition, respectively. Corresponding numbers in women were 16.0, 17.9, 23.6 and 28.8 %. Cumulatively, 88 % of the population has one or more of these while 50 % have three or more.

CONCLUSIONS

The full axis of conditions is high among Mexican Americans in Starr County, Texas. Individual and joint patterns suggest a genesis well before overt disease. Whether they are all mediated by common underlying factors or whether there exist multiple mechanisms remains to be seen.

Clinical consequences and economic costs of untreated obstructive sleep apnea syndrome

Objective

To provide an overview of the healthcare and societal consequences and costs of untreated obstructive sleep apnea syndrome.

Data sources

PubMed database for English-language studies with no start date restrictions and with an end date of September 2014.

Methods

A comprehensive literature review was performed to identify all studies that discussed the physiologic, clinical and societal consequences of obstructive sleep apnea syndrome as well as the costs associated with these consequences. There were 106 studies that formed the basis of this analysis.

Conclusions

Undiagnosed and untreated obstructive sleep apnea syndrome can lead to abnormal physiology that can have serious implications including increased cardiovascular disease, stroke, metabolic disease, excessive daytime sleepiness, work-place errors, traffic accidents and death. These consequences result in significant economic burden. Both, the health and societal consequences and their costs can be decreased with identification and treatment of sleep apnea.

Implications for practice

Treatment of obstructive sleep apnea syndrome, despite its consequences, is limited by lack of diagnosis, poor patient acceptance, lack of access to effective therapies, and lack of a variety of effective therapies. Newer modes of therapy that are effective, cost efficient and more accepted by patients need to be developed.

High prevalence of peripheral arterial disease in patients with obstructive sleep apnoea

INTRODUCTION

Obstructive sleep apnoea (OSA) merits increasing attention as cardiovascular risk factor. Whereas carotid and coronary artery disease have been associated with OSA, occurrence of peripheral arterial disease (PAD) in OSA remains undefined.

METHODS

We screened 100 patients with suspected OSA for PAD. After polysomnography, each patient underwent standardized angiological testing including ankle-brachial index (ABI), central pulse wave velocity, pulse wave index and duplex sonography.

RESULTS

Among total study population, PAD prevalence accounted for 88%, of those 68% had asymptomatic plaques and 20% were symptomatic Fontaine ≥ IIa. In confirmed OSA, prevalence raised up to 98%. Except for smoking habits, distribution of established risk factors did not differ between OSA groups (patients without, mild, intermediate and severe OSA). Presence of plaque, Fontaine PAD stages and intermittent claudication exhibited significant gain with increasing AHI. A logistic regression model revealed that age (OR = 1.199, 95% CI [1.066; 1.348]) and the logarithmically transformed AHI (OR = 5.426, 95% CI [1.068; 27.567]) had the strongest influence on plaque presence. Central pulse wave velocity as marker of arterial stiffness was positively correlated with AHI.

CONCLUSION

OSA is associated with a high prevalence of PAD. This implies substantial diseasés under-recognition and a presumable atherogenic role of OSA in the pathogenesis of PAD. However, vasoprotective impact of OSA treatment remains to be determined.

Effect of CPAP on arterial stiffness in severely obese patients with obstructive sleep apnoea

BACKGROUND

Obstructive sleep apnoea (OSA) may independently increase cardiovascular risk in obesity. Although there is evidence that arterial stiffness is altered in OSA, knowledge of these effects with continuous positive airway pressure (CPAP) in severe obesity (body mass index (BMI) ≥ 35 kg/m(2)) is limited. This study aimed to explore how arterial stiffness, as measured by the augmentation index (Aix), changed in severely obese patients with OSA who were treated with CPAP and in patients without OSA.

METHODS

Forty-two patients with severe obesity-22 with OSA, 20 without OSA-were recruited at baseline and followed-up after a median of 13.5 months. Pulse wave analysis (PWA) was performed using applanation tonometry at the radial artery to measure augmentation index (Aix), augmentation pressure (AP) and subendocardial viability ratio (SEVR). Cardiovascular parameters and body composition were also measured.

RESULTS

There were significant improvements in Aix, AP (both P < 0.001) and SEVR (P = 0.021) in OSA patients on CPAP compared with subjects without OSA. Epworth scores (P < 0.001), systolic (P < 0.001) and mean arterial pressures (P = 0.002) improved with CPAP. Regression showed that CPAP was significantly associated with change in arterial stiffness from baseline. However, patients with OSA on CPAP continued to have increased arterial stiffness (Aix) (P < 0.001), AP (P = 0.028) and reduced SEVR (P = 0.002) relative to non-OSA patients.

CONCLUSION

Although sleepiness and blood pressure improve with CPAP in severe obesity, CPAP alone is not sufficient to modify PWA measures to levels comparable with non-OSA patients. This supports a need for a multifaceted approach when managing cardiovascular risk in patients with severe obesity and obstructive sleep apnoea receiving CPAP therapy.