Obstructive Sleep Apnea, Hypertension, and Their Additive Effects on Atherosclerosis

Obstructive Sleep Apnea Syndrome and Obesity Indicators, Circulating Blood Lipid Levels, and Adipokines Levels: A Bidirectional Two-Sample Mendelian Randomization Study

Purpose

This investigation sought to elucidate the genetic underpinnings that connect obesity indicators, circulating blood lipid levels, adipokines levels and obstructive sleep apnea syndrome (OSAS), employing a bidirectional two-sample Mendelian randomization (MR) analysis that utilizes data derived from extensive genome-wide association studies (GWAS).

Methods

We harnessed genetic datasets of OSAS available from the FinnGen consortium and summary data of four obesity indices (including neck circumference), seven blood lipid (including triglycerides) and eleven adipokines (including leptin) from the IEU OpenGWAS database. We primarily utilized inverse variance weighted (IVW), weighted median, and MR-Egger methods, alongside MR-PRESSO and Cochran's Q tests, to validate and assess the diversity and heterogeneity of our findings.

Results

After applying the Bonferroni correction, we identified significant correlations between OSAS and increased neck circumference (Odds Ratio [OR]: 3.472, 95% Confidence Interval [CI]: 1.954-6.169, P= 2.201E-05) and decreased high-density lipoprotein (HDL) cholesterol levels (OR: 0.904, 95% CI: 0.858-0.952, P= 1.251E-04). Concurrently, OSAS was linked to lower leptin levels (OR: 1.355, 95% CI: 1.069-1.718, P= 0.012) and leptin receptor levels (OR: 0.722, 95% CI: 0.530-0.996, P= 0.047). Sensitivity analyses revealed heterogeneity in HDL cholesterol and leptin indicators, but further multiplicative random effects IVW method analysis confirmed these correlations as significant (P< 0.05) without notable heterogeneity or horizontal pleiotropy in other instrumental variables.

Conclusion

This investigation compellingly supports the hypothesis that OSAS could be a genetic predisposition for elevated neck circumference, dyslipidemia, and adipokine imbalance. These findings unveil potential genetic interactions between OSAS and metabolic syndrome, providing new pathways for research in this domain. Future investigations should aim to delineate the specific biological pathways by which OSAS impacts metabolic syndrome. Understanding these mechanisms is critical for developing targeted prevention and therapeutic strategies.

Obstructive sleep apnea remains a risk factor for major adverse cardiovascular and cerebrovascular events even in hypertensive patients under treatment: the Urumqi Research on Sleep Apnea and Hypertension (UROSAH) data

Background

The impact of the co-occurrence of hypertension and obstructive sleep apnea (OSA) on the risk of long-term cardiovascular disease (CVD) outcomes has not been extensively studied in the Asian population, and the residual effect of OSA on CVD in patients under antihypertensive treatment is not clear. The study aimed to explore the impact of OSA on the risk of CVD outcomes in a large-scale Asian cohort under antihypertensive treatment using retrospective design.

Methods

Hypertensive patients who underwent polysomnography (PSG) test from January 2011 to December 2013 were recruited from the Urumqi Research on Sleep Apnea and Hypertension (UROSAH) cohort, which was conducted in Hypertension Center of People's Hospital of Xinjiang Uygur Autonomous Region. OSA was defined as apnea hypopnea index (AHI) ≥5. Outcomes were extended major adverse cardiovascular and cerebrovascular events (MACCE), including the first occurrence of nonfatal myocardial infarction, nonfatal stroke, revascularization, rehospitalization due to unstable angina or heart failure and all-cause death. Cox regression analysis was performed to explore the effect of OSA and hypertension coexistence on MACCE.

Results

A total of 3,329 hypertension patients were enrolled, of whom 2,585 patients (about 77.7%) suffered from OSA. During a median follow-up period of 7.0 years, 415 patients developed extended MACCE. The incidence of extended MACCE was significantly greater in patients with OSA than those without OSA [hazard ratio (HR): 1.59; 95% confidence interval (CI): 1.27-1.99; P<0.001]. Overall, patients with OSA had an increased risk of cardiac events of 57% compared to those without OSA (HR: 1.57; 95% CI: 1.04-2.39, P=0.034) and the association did not change in further sensitivity analysis. Particularly in uncontrolled hypertension, OSA was found to have a 93% increased risk of cardiac events, compared with patients without OSA (P=0.036).

Conclusions

Untreated OSA seemed to be a factor affecting the prognosis of cardiac events in hypertensive patients, although the association between OSA and cardiac events would be attenuated by the pharmacological-induced blood pressure control, which highlights the need to treat OSA.

A Review of Novel Oximetry Parameters for the Prediction of Cardiovascular Disease in Obstructive Sleep Apnoea

Obstructive sleep apnoea (OSA) is a sleep disorder with repetitive collapse of the upper airway during sleep, which leads to intermittent hypoxic events overnight, adverse neurocognitive, metabolic complications, and ultimately an increased risk of cardiovascular disease (CVD). The standard diagnostic parameter for OSA, apnoea-hypopnoea index (AHI), is inadequate to predict CVD morbidity and mortality, because it focuses only on the frequency of apnoea and hypopnoea events, and fails to reveal other physiological information for the prediction of CVD events. Novel parameters have been introduced to compensate for the deficiencies of AHI. However, the calculation methods and criteria for these parameters are unclear, hindering their use in cross-study analysis and studies. This review aims to discuss novel parameters for predicting CVD events from oximetry signals and to summarise the corresponding computational methods.

Pulmonary rehabilitation and endothelial function in patients with chronic obstructive pulmonary disease: A prospective cohort study

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is associated with subclinical atherosclerosis and endothelial dysfunction, thereby leading to increased cardiovascular risk. In the present study, we evaluated the changes in endothelium-dependent flow-mediated dilation (FMD) in a cohort of severe COPD patients undergoing pulmonary rehabilitation.

METHODS

Consecutive COPD patients referred to our Pulmonary Rehabilitation Unit were screened for inclusion. All study procedures were performed at hospital admission and discharge.

RESULTS

Of 78 patients screened for eligibility, a total of 40 participants (67.5% males, median age 72.5 years) were included. After pulmonary rehabilitation, a significant improvement in functional parameters, exercise capacity, and measures of disability and quality of life were documented. FMD changed from 3.25% (IQR: 2.31-4.26) to 4.95% (IQR: 3.57-6.02), corresponding to a 52.3% increase of its median value (P < 0.001). Significantly lower changes in FMD were documented in COPD patients with hypercholesterolemia as compared to those without (+0.33% ± 1.61 vs. +1.62% ± 1.59, P = 0.037). Changes in FMD (ΔFMD) were positively associated with changes in forced expiratory volume in 1 s (FEV1), when expressed both as absolute values (ΔFEV1) (r = 0.503, P = 0.002) and as percentages of predicted values (ΔFEV1%) (r = 0.608; P < 0.001). In multiple linear regressions, after adjusting for major cardiovascular risk factors, ΔFEV1 (β=0.342; P = 0.049) and ΔFEV1% (β=0.480; P = 0.015) were both confirmed as independent predictors of ΔFMD.

CONCLUSIONS

Results of our study suggest that endothelial function may improve in COPD after pulmonary rehabilitation. The potential beneficial effect in terms of cardiovascular risk prevention should be evaluated in ad hoc designed studies.

Intermittent Hypoxia and Atherosclerosis: From Molecular Mechanisms to the Therapeutic Treatment

Intermittent hypoxia (IH) has a dual nature. On the one hand, chronic IH (CIH) is an important pathologic feature of obstructive sleep apnea (OSA) syndrome (OSAS), and many studies have confirmed that OSA-related CIH (OSA-CIH) has atherogenic effects involving complex and interacting mechanisms. Limited preventive and treatment methods are currently available for this condition. On the other hand, non-OSA-related IH has beneficial or detrimental effects on the body, depending on the degree, duration, and cyclic cycle of hypoxia. It includes two main states: intermittent hypoxia in a simulated plateau environment and intermittent hypoxia in a normobaric environment. In this paper, we compare the two types of IH and summarizes the pathologic mechanisms and research advances in the treatment of OSA-CIH-induced atherosclerosis (AS), to provide evidence for the systematic prevention and treatment of OSAS-related AS.

Early Atherosclerotic Inflammatory Pathways in Children with Obstructive Sleep Apnea

OBJECTIVE

To evaluate structural and functional carotid changes and inflammatory profiles in children with obstructive sleep apnea (OSA) and healthy controls.

STUDY DESIGN

Patients with OSA and matched controls (ages 5-13 years) were recruited. Proinflammatory cytokines and acute phase reactants were measured at 6:00 p.m. Common carotid artery measures were determined using ultrasound. Confirmatory factor analysis was used to determine subgroups of cytokines and their effects on carotid measures.

RESULTS

Ninety-six patients participated (53 healthy controls, 43 patients with OSA). OSA was associated with increased proinflammatory cytokines (cluster of differentiation-40 ligand [CD40-L], interleukin [IL]-6, and IL-8) and high sensitivity C-reactive protein (P < .05 for all). One cytokine subgroup (IL-6 and IL-8) was negatively associated with markers of carotid function, indicating reduced arterial distensibility and increased stiffness (P < .05 for 3 ultrasound measures); and tumor necrosis factor-α had an opposing effect on carotid function compared with this cytokine subgroup (P < .05 for 2 ultrasound measures). Linear regression demonstrated significant associations between and tumor necrosis factor- α and 2 measures of carotid function (P < .05 for each). Children with OSA did not have functional or structural carotid changes compared with controls.

CONCLUSION

OSA was not directly associated with structural and functional carotid changes but was associated with upregulation of key proinflammatory cytokines (sCD40-L, IL-6, and IL-8). Together, IL-6 and IL-8 were associated with changes in carotid function. Longitudinal studies are needed to demonstrate that the inflammatory milieu observed in our population is a precursor of atherosclerosis in children.

Sleep Apnea is Associated With Accelerated Vascular Aging: Results From 2 European Community-Based Cohort Studies

Background The mechanisms underlying the association between obstructive sleep apnea (OSA) and cardiovascular disease may include accelerated vascular aging. The aim was to compare the magnitude of vascular aging in patients with high versus low risk of OSA. Methods and Results In 2 community-based studies, the PPS3 (Paris Prospective Study 3) and the Maastricht Study, high risk of OSA was determined with the Berlin questionnaire (a screening questionnaire for OSA). We assessed carotid artery properties (carotid intima-media thickness, Young's elastic modulus, carotid-femoral pulse wave velocity, carotid pulse wave velocity, carotid diameter using high precision ultrasound echography), and carotid-femoral pulse wave velocity (in the Maastricht Study only). Regression coefficients were estimated on pooled data using multivariate linear regression. A total of 8615 participants without prior cardiovascular disease were included (6840 from PPS3, 62% men, mean age 59.5±6.2 years, and 1775 from the Maastricht Study, 51% men, 58.9±8.1 years). Overall, high risk of OSA prevalence was 16.8% (n=1150) in PPS3 and 23.8% (n=423) in the Maastricht Study. A high risk of OSA was associated with greater carotid intima-media thickness (β=0.21; 0.17-0.26), Young's elastic modulus (β=0.21; 0.17-0.25), carotid-femoral pulse wave velocity (β=0.24; 0.14-0.34), carotid pulse wave velocity (β=0.31; 0.26-0.35), and carotid diameter (β=0.43; 0.38-0.48), after adjustment for age, sex, total cholesterol, smoking, education level, diabetes mellitus, heart rate, and study site. Consistent associations were observed after additional adjustments for mean blood pressure, body mass index, or antihypertensive medications. Conclusions These data lend support for accelerated vascular aging in individuals with high risk of OSA. This may, at least in part, underlie the association between OSA and cardiovascular disease.

Characteristics of Obstructive Sleep Apnea Patients With Hypertension and Factors Associated With Autotitration Acceptance

In order to explore the characteristics and treatment status of obstructive sleep apnea (OSA) patients with hypertension, a retrospective study was conducted on 306 patients admitted from October 2018 to December 2019. According to the apnea hypopnea index (AHI), OSA patients with hypertension were divided into three groups. 69 cases were mild OSA (5 ≤ AHI < 15), 86 cases were moderate (15 ≤ AHI < 30), and 151 cases were severe (AHI ≥ 30). Compared with patients in the mild and moderate groups, the severe group had more male patients, with higher body mass index (BMI) and non-rapid eye movement stage 1 accounted for total sleep time (N1%), and lower non-rapid eye movement stage 2 accounted for total sleep time (N2%), average and minimum blood oxygen. Among all the patients, those who underwent the titration test accounted for 20.6% (63/306). Multivariate analysis showed that sleep efficiency (p < 0.001) and AHI (p < 0.001) were independent factors for patients to accept titration test. OSA patients with hypertension had a low acceptance of titration therapy. These people with higher sleep efficiency and AHI were more likely to receive autotitration.

The effect of high evening blood pressure on obstructive sleep apnea-related morning blood pressure elevation: does sex modify this interaction effect?

PURPOSE

Obstructive sleep apnea (OSA) can lead to increased morning blood pressure (BP). We hypothesized that high evening BP may aggravate OSA-related morning BP elevation. Additionally, this interactional effect may be modified by sex.

METHODS

This retrospective, cross-sectional study included newly diagnosed OSA patients with an apnea-hypopnea index (AHI) ≥ 5 per hour on a full-night polysomnography. An analysis of covariance (ANCOVA) was used to determine whether severe OSA (AHI ≥ 30) was associated with higher morning BP than mild-to-moderate OSA (5 ≤ AHI < 30) and whether there was an interaction between apnea severity and evening BP on morning BP. To identify the sex effects, analyses were performed separately in each sex group.

RESULTS

A total of 1445 patients with an average age of 51.9 years (SD 11.7) (male 77.9% vs. female 22.1%; high evening BP group 22.4% vs. normal evening BP group 59.6%) were included in the study. Based on the ANCOVA, patients with severe OSA had significantly higher morning systolic BP (SBP) (p = 0.003), diastolic BP (DBP) (p < 0.001), and mean BP (MBP) (p < 0.001) than the mild-to-moderate group in male subjects. A significant interaction between apnea severity and evening BP was identified on morning DBP and MBP in male subjects. However, there were no differences in morning BP between severe and mild-to-moderate OSA groups in female subjects.

CONCLUSIONS

In male subjects, severe OSA contributed to higher morning BP than mild-to-moderate OSA. OSA-associated morning BP elevation was more prominent in the high evening BP group than in the normal BP group. Such relations were not found in female subjects.

Plasm YKL-40 Levels Are Associated with Hypertension in Patients with Obstructive Sleep Apnea

Background

Obstructive sleep apnea (OSA) is a common disease. It can cause many serious complications. OSA may increase the risk of hypertension. However, the exact mechanism of OSA causing hypertension is not fully understood. YKL-40/chitinase-3-like protein-1 plays an important role in vascular injury, repair, and generation. We sought to explore the role of YKL-40 in endothelial dysfunction and hypertension in OSA patients.

Methods

All subjects were examined by polysomnography (PSG) and the expression of YKL-40 in the plasm of the subjects was measured by luminex. Carotid intima-media thickness (CIMT) was measured by B-mode ultrasound.

Results

According to the conditions of OSA and hypertension, we studied four groups of 157 subjects, including OSA group (OSA, N=77), OSA with hypertension group (OSA+HT, N=37), hypertension group (HT, N=20), and healthly group (Con, N=23). YKL-40 levels were significantly elevated in OSA, OSA+HT, and HT group compared to Con groups. We used the ROC to predict the sensitivity and specificity of YKL-40 in all OSA patients or all hyperpietic patients. For OSA patients, the AUC of YKL-40 is 0.807 (95% confidence interval 0.725–0.888; p<0.01). For hyperpietic patients, the AUC of YKL-40 is 0.656 (95% confidence interval 0.570–0.742, p=0.01). There was a significant correlation between the parameter of OSA and hypertension and YKL-40 (P<0.05) and a significant correlation between Max-CIMT and YKL-40 (P<0.05).

Conclusion

Elevated circulating levels of YKL-40 are associated with hypertension in OSA patients. The specificity of YKL-40 suggests that it could be a potential biomarker for OSA and hypertension.

Pentraxin-3 and endothelial dysfunction

Pentraxin 3 (PTX3) is involved in vascular inflammation and endothelial dysfunction through various mechanisms. Until now, most studies confirmed an important link between PTX3 and endothelial dysfunction and identified several pathogenetic pathways. PTX3 modulates inflammatory cells, thus stimulating vascular inflammation. Within endothelial cells, it decreases nitric oxide (NO) synthesis, inhibits cell proliferation and alters their functions. PTX3 blocks the effect of fibroblast growth factor 2 (FGF2) by making a molecular complex with these molecules inactivating them. However, there are substances like the tumor necrosis factor-inducible gene 6 protein (TSG-6) that block the PTX3-FGF2 interaction. Interacting with P-selectin, it promotes vascular inflammatory response and endothelial dysfunction. PTX3 also increases the matrix metalloproteinases synthesis directly or by blocking NO synthesis. From a clinical point of view, PTX3 positively correlates with arterial hypertension, flow mediated dilation and, with intima media thickness. Therefore, the involvement of PTX3 in the pathogenesis and evaluation of endothelial dysfunction is clear, and it may become a biomarker in this direction, but further studies are needed to determine its reliability in this direction. Last but not least, PTX3 could become an effective therapeutic target for preventing this dysfunction, but further research needs to be conducted.

Quantitative analysis of carotid arterial calcification using airway CT in obstructive sleep apnea

OBJECTIVE

To evaluate the relationship between obstructive sleep apnea (OSA) severity and carotid arterial calcification by quantitative analysis using airway computed tomography (CT).

METHODS

This study included a total of 180 consecutive OSA patients aged 45-80years underwent polysomnography and airway CT between March 2014 and October 2016. The subjects were divided into three groups based on the results of the respiratory disturbance index (RDI): mild (RDI 5-14, n=29), moderate (RDI 15-29, n=50), and severe (RDI≥30, n=101). The extent of carotid arterial calcification on each airway CT scan was quantified according to the modified Agatston scoring method. Differences among the three groups in clinical characteristics including age, gender, body mass index (BMI), comorbid disease, blood pressure, total cholesterol, and carotid arterial calcification score (CarACS) were analyzed.

RESULTS

The severe OSA group showed significantly stronger predominance for male and smoker, higher prevalence of diabetes, and larger BMI than those of mild and moderate OSA groups. The mean CarACS was significantly different among the three groups (mild RDI: 4.3±13.4, moderate RDI: 7.4±28.8, severe RDI: 48.6±121.6, P=0.011). Univariate linear regression showed that RDI, age, hypertension, male sex and diabetes significantly influenced on the CarACS. In a multivariate linear regression model, the CarACS was related to age, male sex, and diabetes.

CONCLUSIONS

The patients with severe OSA showed larger CarACS and a higher prevalence of atherosclerotic risk factors. The CarACS was correlated with severity of OSA, which might be more dependent on the conventional risk factors of atherosclerosis.

The additive effects of OSA and nondipping status on early markers of subclinical atherosclerosis in normotensive patients: a cross-sectional study

The additive effect of hypertension on carotid atherosclerosis in patients with obstructive sleep apnea (OSA) is well-established; however, the effect of the nondipping pattern has not yet been evaluated. In this study, we aim to assess the effect of the nondipping pattern on carotid atherosclerosis, which is quantified as carotid intima-media thickness (CIMT), and on the high-risk carotid profile in normotensive patients with OSA. We included 189 patients with OSA in this cross-sectional study. We followed a 2 × 2 factorial design to create groups according to the presence of OSA and nondipping pattern. All patients underwent carotid ultrasonography to quantify their CIMT and presence of plaques. Patients who had CIMT ≥ 0.9 mm and/or carotid plaques were classified as having a high-risk carotid profile. Patients in the OSA/nondipper group had a 26% higher CIMT and five times the prevalence of a high-risk carotid profile compared to patients in the non-OSA/dipper group. CIMT was correlated with age, the apnea-hypopnea index (AHI), minimum oxygen saturation, and nighttime systolic blood pressure (SBP). Independent of age, diabetes, and AHI, a one mmHg increase in nighttime SBP was associated with a 0.22 mm increase in CIMT and a 4% increase in odds for the high-risk carotid profile. Similarly, independent of age and diabetes, being in the OSA/nondipper group was associated with 6.7 times increased odds for a high-risk carotid profile than being in the non-OSA/dipper group. Modeling with both the nondipping status and presence of OSA produced an 8% higher discriminative value than modeling with neither of these parameters. We found an additive effect of the nondipping pattern on carotid atherosclerosis in normotensive patients with OSA. Our findings suggested that in addition to having established hypertension, a nondipping pattern in normotensive patients with OSA may aggravate atherosclerosis.

Carotid Artery Wall Thickness in Obese and Nonobese Adults With Obstructive Sleep Apnea Before and Following Positive Airway Pressure Treatment

Study objectives

Debate persists as to whether obstructive sleep apnea (OSA) is an independent risk factor for atherosclerosis. The purpose of this study was to compare carotid intima-media thickness (IMT), an early sign of atherosclerosis, in obese and nonobese adults with OSA before and following positive airway pressure (PAP) treatment.

Methods

A total of 206 adults newly diagnosed with OSA with an apnea-hypopnea index (AHI) of 15-75 events/hour and 53 controls with AHI <10 were studied. Waist circumference was used to classify participants as obese and nonobese. Bilateral common carotid artery B-mode ultrasound was performed at baseline to assess IMT, arterial diameter, arterial-wall mass, and circumferential wall stress. Measurements were repeated in 118 participants with OSA who completed a 4-month PAP treatment and had an average daily use over that period of ≥4 hours/day.

Results

No significant differences in carotid IMT, diameter, or arterial-wall mass were present at baseline between participants with OSA and controls stratified by waist circumference, after adjusting for other cardiovascular risk factors. In participants with OSA, who had adequate PAP adherence over the 4-month treatment, carotid artery diameter significantly increased (mean change [95% confidence interval] = 0.13 [0.06, 0.20] mm; p = .0004), but no significant changes in carotid IMT, arterial-wall mass, and circumferential stress were observed in obese and nonobese participants.

Conclusions

Regardless of obesity status, carotid IMT is not increased in adults with moderate to severe OSA versus controls and does not change following 4 months of PAP treatment.

Activating adenosine A1 receptor accelerates PC12 cell injury via ADORA1/PKC/KATP pathway after intermittent hypoxia exposure

Obstructive sleep apnea hypopnea syndrome (OSAHS) is associated with the neurocognitive deficits as a result of the neuronal cell injury. Previous studies have shown that adenosine A1 receptor (ADORA1) played an important role against hypoxia exposure, such as controlling the metabolic recovery in rat hippocampal slices and increasing the resistance in the combined effects of hypoxia and hypercapnia. However, little is known about whether ADORA1 takes part in the course of neuronal cell injury after intermittent hypoxia exposure which was the main pathological characteristic of OSAHS. The present study is performed to explore the underlying mechanism of neuronal cell injury which was induced by intermittent hypoxia exposure in PC12 cells. In our research, we find that the stimulation of the ADORA1 by CCPA accelerated the injury of PC12 cells as well as upregulated the expression of PKC, inwardly rectifying potassium channel 6.2(Kir6.2) and sulfonylurea receptor 1(SUR1) while inhibition of the ADORA1 by DPCPX alleviated the injury of PC12 cells as well as downregulated the expression of PKC, Kir6.2, and SUR1. Moreover, inhibition of the PKC by CHE, also mitigated the injury of PC12 cells, suppressed the Kir6.2 and SUR1 expressions induced by PKC. Taken together, our findings indicate that ADORA1 accelerated PC12 cells injury after intermittent hypoxia exposure via ADORA1/PKC/K_ATP signaling pathway.

Changes in inflammatory mediators as a result of intermittent hypoxia in obstructive sleep apnea syndrome

BACKGROUND

Inflammation plays an important role in obstructive sleep apnea syndrome (OSAS). The objective of this study was to investigate the relationship of serum C-reactive protein (CRP), pentraxin-3 (PTX-3), procalcitonin (ProCT), interleukin-33 (IL-33) and its soluble receptor ST2 (sST2) with the syndrome severity and to show theirs importance as biomarkers.

METHODS

This study comprises a total of 84 identical (sex and age wise) cases. Full-night polysomnography was performed in each patient. OSAS diagnosis and severity index being based on the widely used criterion known as Apnea Hypopnea Index(AHI). Subgroups were as follows: 24(AHI < 5) controls, 28 mild-moderate OSAS(AHI 5-30) and 32 severe OSAS(AHI > 30).

RESULTS

PTX-3, IL-33 and sST2 receptors were significantly higher in OSAS groups than the control group (P < .001). However, both CRP and ProCT levels were similar in all subjects. There was a positive correlation between PTX-3 and BMI (r = 0.446; P < .01), ODI (r = 0.555; P < .01), IL-33 (r = 0.348; P = .001) and sST2 (r = 326; P = .002), while there was a negative correlation with minimum SaO₂ (r = -0.672; P < .01) in patient group. PTX-3 as a predictor of OSAS showed highest specificity (%91.7) and sensitivity (%91.7) (P < .001).

CONCLUSIONS

PTX-3 can be a new indicator reflecting the inflammatory state in patients with OSAS. Since patients with OSAS could have more hypoxic state during sleep, we found higher PTX-3 level in those patients and a negative correlation between PTX-3 and minimum SaO₂ , which could explain that PTX-3 levels can increase with the severity of disease. Our results suggest that PTX-3 as an inflammatory biomarker may play a crucial role as an indicator of syndrome severity in OSAS.

Circulating lipopolysaccharide-binding protein and carotid intima-media thickness in obstructive sleep apnea

Circulating lipopolysaccharide-binding protein (LBP), a metabolic endotoxemia marker, was identified as an independent predictor of atherosclerosis. Although increases in carotid intima-media thickness (CIMT) were repeatedly reported in obstructive sleep apnea (OSA), neither the role of OSA in metabolic endotoxemia nor of LBP in early atherosclerosis were explored in patients with OSA. At a tertiary university hospital we investigated the relationships between OSA, LBP and CIMT in 117 men who underwent full polysomnography and CIMT assessment by B-mode ultrasound. Circulating LBP concentrations and average CIMT increased from patients without OSA to those with mild-moderate and severe OSA (from 32.1+/-10.3 to 32.3+/-10.9 to 38.1+/-10.3 microg.ml(-1), p=0.015; from 0.52+/-0.09 to 0.58+/-0.06 to 0.62+/-0.10 mm, p=0.004, respectively). Oxygen desaturation index (ODI) was a predictor of serum LBP levels independent of age, waist-to-hip ratio (WHR), smoking, hypertension, HDL cholesterol, triglycerides and fasting glucose [p (ANOVA)=0.002, r(2)=0.154], with no independent effect of the ODI*WHR interaction term on LBP. Furthermore, serum LBP predicted CIMT independently of known risk factors of atherosclerosis including obesity (p<0.001, r(2)=0.321). Our results suggest that OSA severity contributes to metabolic endotoxemia in patients with OSA independently of obesity, and that LBP might represent a contributing factor promoting early atherosclerosis in such patients.

Does Cardiovascular Comorbidity Influence the Prescribing of Bronchodilators in Chronic Obstructive Pulmonary Disease?

BACKGROUND

Cardiovascular disease (CVD) is the most prevalent comorbidity for chronic obstructive pulmonary disease (COPD). Potential adverse cardiovascular events of bronchodilators warrant their cautionary use in the comorbid COPD-CVD population, yet little is known about the prescribing of bronchodilators in this high-risk patient group.

OBJECTIVE

To determine whether comorbid CVD is associated with reduced bronchodilator prescribing in patients with COPD. In addition, we explored how the association was modified by gender, concurrent asthma, and concomitant β-blocker (BB) use.

METHODS

A cross-sectional study was conducted using the 2010 National Ambulatory Medical Care Survey. All visits among diagnosed COPD patients 40 years and older were examined. Logistic regression on survey-weighted data was used to predict treatment with bronchodilators and determine the influence of gender, asthma, and BBs on bronchodilator prescribing.

RESULTS

Among 11 627 061 ambulatory COPD visits, we found a significantly lower bronchodilator treatment rate among patients with comorbid CVD (32.3%) than among patients without CVD (57.6%). The observed effect was modified by gender, asthma, and BBs. Deprescribing was more pronounced for females than males, for nonusers of BBs than users of BBs, and for asthma patients than nonasthma patients. CVD did not affect bronchodilator prescribing in either asthmatic or nonasthmatic males taking BBs.

CONCLUSIONS

Most COPD patients with concurrent CVD were less likely to be prescribed bronchodilators, with the exception of males who were also prescribed BBs. Thus, this study highlights a specific patient subgroup for whom the guidelines are less likely to be observed.

Research Article. Characteristics of Sleep Apnea Assessed Before Discharge in Patients Hospitalized with Acute Heart Failure

Objectives. Evaluation of the characteristics of sleep apnea (SA) in patients hospitalized with acute heart failure, considering that undiagnosed SA could contribute to early rehospitalization. Methods. 56 consecutive patients (13 women, 43 men, mean age 63.12 years) with acute heart failure, in stable condition, underwent nocturnal polygraphy before hospital discharge. The type and severity of SA was determined. Besides descriptive statistics, correlations between the severity of SA and clinical and paraclinical characteristics were also analyzed (t-test, chi-square test, significancy at alpha < 0.05). Results. 12 (21.4%) subjects were free of SA (AHI - apnea-hipopnea index <5/h), 15 (26.7%) had mild SA (AHI=5-14/h), 17 (30.3%) had moderate SA (AHI 15-30/h), and 12 (21.4 %) had severe SA (AHI>30/h). The apnea was predominantly obstructive (32 cases vs. 12 with central SA). Comparing the patients with mild or no SA with those with severe SA, we did not find statistically significant correlations (p>0.05) between the severity of SA and the majority of main clinical and paraclinical characteristics - age, sex, BMI, cardiac substrates of heart failure, comorbidities. Paradoxically, arterial hypertension (p=0.028) and atrial fibrillation (p=0.041) were significantly more prevalent in the group with mild or no SA. Conclusions. Before discharge, in the majority of patients hospitalized with acute heart failure moderate and severe SA is present, and is not related to the majority of patient related factors. Finding of significant SA in this setting is important, because its therapy could play an important role in preventing readmissions and improving prognosis.