The Change of Interleukin-6 and Tumor Necrosis Factor in Patients with Obstructive Sleep Apnea Syndrome

The levels of lipopolysaccharide (LPS) induced interleukin 6 (IL 6) and tumor necrosis factor α (TNF α) expression in culture of peripheral blood mononuclear cells (PBMC) and the plasma levels of IL 6 and TNF α in the patients with obstructive sleep apnea syndrome (OSAS) were measured and the relationship between OSAS and IL 6 or TNF α expression studied. Both IL 6 and TNF α were detected by using ELISA in 22 patients with OSAS and 16 normal controls. The levels of LPS induced IL 6 (787.82±151.97 pg/ml) and TNF α (4165.45±1501.43 pg/ml) expression in the supernatant of the culture of PBMC and plasma level of IL 6 (50.67±4.70 pg/ml) and TNF α (299.09±43.57 pg/ml) in the patients with OSAS were significantly higher than those in the normal controls (in the supernatant of the culture of PBMC: 562.69±197.54 pg/ml and 1596.25±403.08 pg/ml respectively; in the plasma: 12.69±2.75 pg/ml and 101.88±21.27 pg/ml respectively). There were significantly positive correlation between the levels of IL 6 and TNF α and the percentage of time of apnea and hyponea, as well as the percentage of time spending at SaO 2 below 90 % in the total sleep time. It was concluded that LPS induced IL 6 and TNF α levels as well as plasma IL 6 and TNF α levels in the patients with OSAS were up regulated, which may be associated with the pathogenesis of OSAS.

Retinal nerve fiber layer thickness changes in obstructive sleep apnea syndrome: one year follow-up results

·AIM: To investigate the retinal nerve fiber layer(RNFL)thickness changes in patients with obstructive sleep apnea syndrome(OSAS) for one year follow-up. To discuss the possibility of detecting tendency of glaucoma in this population by using spectral domain optical coherence tomography(3D-OCT-2000 Spectral domain).·METHODS: After polysomnographic study, all subjects(64 OSAS patients and 40 controls) underwent detailed ophthalmological examination. After these examinations,patients with glaucoma and patients who had ophthalmological and/or systemic disease were excluded from the study.Totally, 20 patients in OSAS group and five patients in controls were excluded from the study in the first examination and follow-up period. The RNFL thickness was assessed with OCT. Forty-four OSAS patients and 35 control subjects were followed up for12 mo. RNFL thickness change and OSAS patients were evaluated for severity of disease by Apnea-Hypopnea Index(AHI).·RESULTS: Forty-four OSAS patients and 35 controls were enrolled in the study. Statistically significance was found between OSAS patients and controls at the 12 thmo.Average RNFL thickness was found to be significantly lower in last measurements in OSAS patients when compared with first measurements and control subjects(P 【0.001, 0.002, respectively). There was a statistically significant correlation among AHI, and RNFL thickness(P 【0.05).·CONCLUSION: The results suggest that the patients with OSAS were related with a proportional decrease in the RNFL thickness. These patients should be followed up regularly for glaucomatous changes. Detecting more RNFL thinning in severe OSAS was important.

Electrical Stimulation Therapy Improves Sleep Respiratory Parameters in Obstructive Sleep Apnea Syndrome: A Meta-analysis

Recent clinical trials have shown that electrical stimulation has beneficial effects in obstruc- tive sleep apnea syndrome （OSAS）. The purpose of this study was to evaluate the efficacy of electrical stimulation therapy for OSAS with a meta-analysis. The meta-analysis of all relative studies was per- formed through searching international literature, including PUBMED, CNKI, and EMBASE databases. This literature analysis compared all patients undergoing electrical stimulation therapy with respect to the respiratory disturbance index （RDI） and changes in sleep structure. Six studies were selected in- volving a total of 91 patients. The meta-analysis indicated that electrical stimulation therapy reduced RDI, longest apnea time, and improved the minimum SaO2. Based on the evidence found, electrical stimulation may be a potential therapy for OSAS, warranting further clinical trials.

Retinal nerve fiber layer thickness changes in obstructive sleep apnea syndrome:a systematic review and Metaanalysis

AIM： To evaluate the retinal nerve fiber layer（RNFL）thickness changes in patients with obstructive sleep apnoea syndrome（OSAS）, and detect possible prevalence of glaucoma in this population.METHODS： Comprehensive studies were conducted on the Cochrane Library, Pub Med and Embase through March, 2015. Only studies that fit the selection criteria about RNFL and OSAS would be included. For the measures, we calculated the 95% confidence interval（CI）and weighted mean differences（WMD）. The systematic review and Meta-analysis was performed by Rev Man 5.2software.RESULTS： Nine case-control studies were analyzed containing a total of 1086 cases and 580 controls.Average RNFL thickness in OSAS was reduced significantly compared with healthy controls in random effects model（WMD =-2.56, 95% CI：-4.82 to-0.31, P =0.003, I2=57%）. A significant RNFL thickness reduction were found between the two groups in inferior quadrant（WMD =-3.11, 95% CI：-5.53 to-0.69, P =0.01）, superior quadrant（WMD =-2.37, 95% CI：-4.7 to 0.04, P =0.05）. In nasal quadrant（WMD =-2.54, 95% CI：-6.53 to 1.45, P =0.21） and temporal quadrant（WMD=-1.26, 95% CI：-2.19 to 0.47, P =0.15） there was no difference of RNFL thickness between the two groups.CONCLUSION： The results show that RNFL thickness is lower in patients with moderate or severe OSAS than in normal subjects or patients with mild OSAS according to the nine homogeneity studies.

Evaluation of choroidal thickness using spectral-domain optical coherence tomography in patients with severe obstructive sleep apnea syndrome: a comparative study

AIM: To assess choroidal thickness in patients with severe obstructive sleep apnea syndrome(OSAS) and compare them with healthy controls, using spectral domain optical coherence tomography(OCT).METHODS: In this observational, cross-sectional study,choroidal thicknesses of 23 newly severe OSAS patients and 23 body mass index- age- and sex-matched healthy subjects were measured using a high-speed, high-resolution frequency domain- OCT device( λ = 840 nm,26 000 A-scans/s, 5 μm axial resolution). All patients underwent a complete ophthalmic examination before the measurements. OCT measurements were taken at the same time of day(9:00 a.m.), in order to minimize the effects of diurnal variation.RESULTS: There was a statistically significant difference in median choroidal thickness between the OSAS patients(201 μm; range 145-237 μm) and the controls(324 μm; range 296-383 μm;P 【0.001). There were significant differences at all measurement points(P 【0.001 for all). The apnea-hypopnea index(AHI)values were more than 30 in all OSAS patients and the mean AHI was 48.57 ±6.54. The interexaminer intraclass correlation coefficient(ICC) for the mean choroidal thickness was 0.938(95% CI, 0.908-0.985) and ICC was greater than 0.90 for all measurement points.CONCLUSION: The decreased choroidal thickness of patients with severe OSAS might be related to the the autonomic disregulation associated with this disease.Further studies are needed to evaluate the etiopathologic relationship between choroidal thickness and OSAS.

Computational Fluid Dynamics Simulation of the Upper Airway of Obstructive Sleep Apnea Syndrome by Muller Maneuver

This study aimed to use computer simulation to describe the fluid dynamic characteristics in patients with obstructive sleep apnea syndrome（OSAS） and to evaluate the difference between during quiet respiration and the Muller maneuver（MM）. Seven patients with OSAS were involved to perform computed tomographic（CT） scanning during quiet respiration and the MM. CT data in DICOM format were transformed into an anatomically three-dimensional computational fluid dynamics（CFD） model of the upper airway. The velocity magnitude, relative pressure, and flow distribution were obtained. Numerical simulation of airflow was performed to discuss how the MM affected airflow in the upper airway. To measure the discrepancy, the SPSS19.0 software package was utilized for statistic analysis. The results showed that the shape of the upper airway became narrower, and the pressure decreased during the MM. The minimal cross-sectional area（MCSA） of velopharynx was significantly decreased（P〈0.05） and the airflow velocity in MCSAs of velopharynx and glossopharynx significantly accelerated（P〈0.05） during the MM. This study demonstrated the possibility of CFD model combined with the MM for understanding pharyngeal aerodynamics in the pathophysiology of OSAS.

The Diagnosis Value and Its Implication of Impulse Oscillometry in Obstructive Sleep Apnea Syndrome Patients

The change of measurements of impulse oscillometry (105) in obstructive sleep apnea syn- drome (OSAS) patients and its mechanism were observed. The respiratory impedance was measured by using IOS technique and polysomnography (PSG) was monitored synchronously in 36 OSAS pa- tients,14 patients with chronic obstructive pulmonary disease (COPD) and 12 normal controls. Re- sults showed that R20 in OSAS group was significantly higher than in COPD group and control group (P<0.01). R5-R20 in OSAS group was lower than that in COPD group, but significantly higher than that in control group(P<0. 01). The levels of R20 and R5-R20 were positively correlated with severity degree of the disease. In addition, apnea-hyponea index (AHI) was positively correlated with R5 and R20 with the correlation index (r)being 0. 66 and 0. 86 respectively. The lowest SO2 was negatively correlated with R5 and R5-R20, with r being-0. 66 and- 0. 79 respectively. The mean SO2 was negatively correlated with R5 and R5-R20 with r being-0. 81 and-0. 69 respectively. IOS technique could be used as a valuable tool for assessing the degree of upper airway obstruction in the patients with OSAS, and could help to explore its pathological mechanism.

A Very Severe Obstructive Sleep Apnea Syndrome: In a Cause of Resistant Hypertension with One Sample Case

When blood pressure values remain above the target in a hypertensive patient treated concomitantly with three anti-hypertensive drugs including a diuretic, maximum well-tolerated doses, this is a resistant arterial hypertension. In this case, it is advisable to look for a secondary cause such as a drug intake that influencing the blood pressure or the presence of obstructive sleeping syndrome (OSAS). We report a clinical case of a patient with a high cardiovascular risk at the age of 50, hypertensive and diabetic, with dyslipidemia and obesity. He was on anti-hypertensive triple therapy at an optimal dose. Her diabetes was balanced with 6.4% glycated hemoglobin. Dyslipidemia has being treated. Despite healthy diet including a low sodium diet and weight loss, blood pres- sure target was not reached. With self-measurement, the mean arterial pressure was 180/110 mmHg and on ABPM it was 167/113 mmHg. The ventilatory polygraphy finds a severe OSA with an IAH = 56.6. Treatment with PCP (Con- tinuous positive pressure) allowed this patient to control blood pressure. The search for OSA should be systematic in face of resistant hypertension, in par- ticular in overweight or obese patients.

Obstructive Sleep Apnea Syndrome Phenotyping by Cluster Analysis: Typical Sleepy, Obese Middle-aged Men with Desaturating Events are A Minority of Patients in A Multi-ethnic Cohort of 33% Women

Objective Several clinical obstructive sleep apnea syndrome(OSAS)phenotypes associated with heterogeneous cardiovascular risk profiles have been recently identified.The purpose of this study was to identify clusters amongst these profiles that allow for the differentiation of patients.Methods This retrospective study included all moderate-to-severe OSAS patients referred to the sleep unit over a 5-year period.Demographic,symptom,comorbidity,polysomnographic,and continuous positive airway pressure(CPAP)adherence data were collected.Statistical analyses were performed to identify clusters of patients.Results A total of 567 patients were included(67%men,54±13 years,body mass index:32±7 kg/m2,65%Caucasian,32%European African).Five clusters were identified:less severe OSAS(n=172);healthier severe OSAS(n=160);poorly sleeping OSAS patients with cardiometabolic comorbidities(n=87);younger obese men with sleepiness at the wheel(n=94);sleepy obese men with very severe desaturating OSAS and cardiometabolic comorbidities(n=54).Patients in clusters 3 and 5 were older than those in clusters 2 and 4(P=0.034).Patients in clusters 4 and 5 were significantly more obese than those in the other clusters(P=0.04).No significant differences were detected in terms of symptoms and comorbidities.Polysomnographic profiles were very discriminating between clusters.CPAP adherence was similar in all clusters but,among adherent patients,daily usage was more important in cluster 1(less severe patients)than in cluster 5.Conclusion This study highlights that the typical sleepy obese middle-aged men with desaturating events represent only a minority of patients in our multi-ethnic moderate-to-severe OSAS cohort of 33%females.

Meta-analysis of randomized controlled trials of traditional Chinese medicine in the treatment of obstructive sleep apnea syndrome

Objective:Though Chinese medicine(CM)has showed its clinical efficacy for the treatment of obstructive sleep apnea(OSA)in China,no systematic reviews or meta-analyses provide evidences for its therapeutic effects on OSA and the long-term safety.The aim of the present study is to evaluate the effectiveness and safety of CM on OSA using meta-analysis.Methods:We used search items of"Chinese Medicine"AND"obstructive sleep apnea"to retrieve the randomized control trials(RCTs)of CM treatments for OSA in PubMed,Embase,Cochrane Library,China National Knowledge Infrastructure(CNKI),VIP database,and Wanfang database from their respective inception dates to December 2019.Only RCTs of CM therapy versus no treatment which could be quantitatively synthesized were included.Finally,20 studies representing 1,297 participants were included after extraction.Two investigators independently extracted and analyzed the data using RevMan5.3 software.Results:The treatment group using CM decoctions or CM granules presented significantly ameliorative effects on apnoea-hypopnoea index(AHI)compared with the control group(MD:-2.58,95%CI:-3.59 to-1.56,P<0.00001 and MD:-5.47,95%CI:-6.75 to-4.19,P<0.00001,respectively)in the sensitivity analysis.However,there were non significant differences in the duration of treatment between subgroups,indicating that the duration of treatment has no impacts on the therapeutic effects on AHI.CM granules also showed significantly ameliorative effects on the lowest nocturnal oxygen saturation(LSaO2)(MD:2.76,95%CI:1.85 to 3.68,P<0.00001).CM decoctions exhibited significantly improved Epworth Sleepiness Scale(ESS)scores compared with the control group in a sensitivity analysis(MD:-1.50,95%CI:-2.13 to-0.88,P<0.00001).CM granules showed a better improvement of ESS than the control group(MD:-1.35,95%CI:-1.92 to-0.78,P<0.00001).Mild adverse reactions occurred only in five patients and disappeared without special treatment.Conclusion:This study showed favorable therapeutic efficacy of CM on OSA.However,in consideration of the low methodological quality of the included RCTs,more rigorous designed,large sample size RCTs are recommended for providing more high-quality evidences.

Causal role of immune cells in obstructive sleep apnea hypopnea syndrome:Mendelian randomization study

BACKGROUND Despite being one of the most prevalent sleep disorders,obstructive sleep apnea hypoventilation syndrome(OSAHS)has limited information on its immunologic foundation.The immunological underpinnings of certain major psychiatric diseases have been uncovered in recent years thanks to the extensive use of genome-wide association studies(GWAS)and genotyping techniques using highdensity genetic markers(e.g.,SNP or CNVs).But this tactic hasn't yet been applied to OSAHS.Using a Mendelian randomization analysis,we analyzed the causal link between immune cells and the illness in order to comprehend the immunological bases of OSAHS.AIM To investigate the immune cells'association with OSAHS via genetic methods,guiding future clinical research.METHODS A comprehensive two-sample mendelian randomization study was conducted to investigate the causal relationship between immune cell characteristics and OSAHS.Summary statistics for each immune cell feature were obtained from the GWAS catalog.Information on 731 immune cell properties,such as morphologic parameters,median fluorescence intensity,absolute cellular,and relative cellular,was compiled using publicly available genetic databases.The results'robustness,heterogeneity,and horizontal pleiotropy were confirmed using extensive sensitivity examination.RESULTS Following false discovery rate(FDR)correction,no statistically significant effect of OSAHS on immunophenotypes was observed.However,two lymphocyte subsets were found to have a significant association with the risk of OSAHS:Basophil%CD33dim HLA DR-CD66b-(OR=1.03,95%CI=1.01-1.03,P<0.001);CD38 on IgD+CD24-B cell(OR=1.04,95%CI=1.02-1.04,P=0.019).CONCLUSION This study shows a strong link between immune cells and OSAHS through a gene approach,thus offering direction for potential future medical research.

Epidemiological and Clinical Profile of Hypertensive Patients with Obstructive Sleep Apnea at CHU-B

Objectives: To detect obstructive sleep apnea syndrome (OSAS) in a population of hypertensive patients, using the Berlin questionnaire and to establish the epidemiological and clinical profile of patients. Patients and Method: This was a cross-sectional and analytical study, carried out from March to August 2019 at the CHU Brazzaville. Included are hypertensive patients followed as outpatients. The diagnosis of the OSAS was based on the answers to the Berlin questionnaire. Results: A total of 315 patients were included, including 210 women (64.9%). Prevalence of OSAS was 75.8% (n = 239). The average age of patients with sleep apnea was 58.5 ± 12.4 years with female predominance (64.9%). In the mixed analysis, the factors associated with (OSAS) were: occupation OR (2.56) 95% CI (1.15 - 5.69), obesity OR 7.50 (1.60 - 35.1) and abdominal obesity OR 2.36 CI 95% (1.36 - 4.08). Living standards were high in 59 cases (18.7 per cent). The medical history of previous hospitalization was present in 209 cases (66.3%), diabetes 95 (30.2%), and heart failure 57 cases (18.1%). Lifestyle patterns were: sedentary (n = 181;57.5%) alcohol consumption (n = 97;30.8%). On physical examination, overweight was noted in 96 cases (30.5%) and obesity in 91 cases (28.8%). The anomalies in the Berlin questionnaire were: snoring (n = 197;62.5%), waking fatigue (n = 127;40.3%), fatigue during the day (n = 97;30.8%). Conclusion: The prevalence of obstructive sleep apnea syndrome is high during arterial hypertension in our setting. Hence the need for sleep exploration through polysomnography, and prevention through the fight against the associated risk factors.

Effect of continuous positive airway pressure treatment on serum adiponectin level and mean arterial pressure in male patients with obstructive sleep apnea syndrome

Background Recent research suggested that obstructive sleep apnea syndrome （OSAS） might be independently associated with hypoadiponectinemia, which was linked to some complications of OSAS, such as hypertension, diabetes etc. This study was conducted to investigate the effect of continuous positive airway pressure （CPAP） treatment on changes of both serum adiponectin levels and mean arterial pressure and their possible links in male OSAS patients. Methods Twenty-three adult male patients with moderate-to-severe OSAS but without obesity, coronary heart disease and diabetes were recruited. Their blood samples were collected and morning mean arterial pressure （MAP） was measured before CPAP treatment and on day 3, 7, 14 of CPAP treatment respectively. The serum adiponectin concentration was tested with radioimmunoassay. Results Compared with the serum adiponectin level before CPAP treatment, no significant change was found in OSAS patients on day 3 and day 7 of CPAP treatment （P〉0.05）. It was not until day 14 of CPAP treatment did a significant elevation in serum adiponectin level occur （P〈0.01）. Meanwhile, the MAP showed no statistically significant difference among its levels before CPAP, on day 3 and day 7 of CPAP treatment （P〉0.05）. However, on day 14 of CPAP treatment, a significantly lower MAP than that obtained before treatment was observed （P〈0.05）. Conclusions CPAP treatment can gradually reverse hypoadiponectinemia and reduce MAP in OSAS patients. Hypoadiponectinemia might be involved in the pathogenesis of OSAS-mediated hypertension.

Effects of Continuous Positive Airway Pressure on Cognitive Deficits in Middle-aged Patients with Obstructive Sleep Apnea Syndrome： A Meta-analysis of Randomized Controlled Trials

Background： Current views on continuous positive airway pressure （CPAP） treatment to improve the cognitive deficits of patients with obstructive sleep apnea syndrome （OSAS） are controversial, so we performed a meta-analysis. Methods： A comprehensive literature search was undertaken in PubMed, CINAHL, Medline, Psyclnfo, EMBASE, Cochrane Library, CNKI, WanFang, VIP, and CBMdisc for studies published from June 1971 to July 2014. The outcome measures included neuropsychological tests of the 7 cognitive domains detailed below. Results： After screening the titles and abstracts and thoroughly reading the fuU text, we obtained 13 studies with little risk of bias that incorporated 1744 middle-aged obese participants with mild to severe OSAS. The studies were published from 1994 to 2012. Treatment durations varied from 1 to 24 weeks. The effect sizes of attention, vigilance, processing speed, working memory, memory, verbal fluency, and visuoconstructive skills domains were -0.10 （P = 0.24）, -0.12 （P = 0.04）, -0.08 （P = 0.16）, 0.00 （P = 0.95）, -0.04 （P = 0.30）, -0.06 （P = 0.34）, and -0.01 （P = 0.92）, respectively. Conclusions： Cognition partially improved in patients with OSAS after CPAP treatment. The only domain with significant improvement was vigilance. Rigorous randomized controlled trials need to be performed to obtain clear results.

Correlation among obstructive sleep apnea syndrome,coronary atherosclerosis and coronary heart disease

Epidemiologic investigations have shown that the morbidity of obstructive sleep apnea syndrome （OSAS） among adults is 2%-4%, among the population aged 30 years and over is 4.63%, and among patients with hypertension or coronary atherosclerostic disease （CAD） is as high as 30%-50%.1 Many studies have indicated that OSAS may be closely associated with the development of CAD since increased incidence and mortality of CAD were found in OSAS patients. However, although it has been confirmed that OSAS is an independent risk factor for hypertension, its exact correlation with CAD has not been entirely elucidated. The aim of the present study was to explore the correlation between the degrees of OSAS and CAD with the application of coronary artery angiography （CAA）, Gensini scoring evaluation system, and other risk factors which may contribute to CAD.

Elevated nocturnal and morning blood pressure in patients with obstructive sleep apnea syndrome

Background The nocturnal nondipping and elevated morning blood pressure （BP） in patients with obstructive sleep apnea syndrome （OSAS） have not yet been well investigated in Chinese patients. This study aimed to describe the BP profile, and to elucidate the relationships between daytime BP and nighttime BP, and between evening BP and morning BP in patients with OSAS. Methods Twenty teaching hospital sleep centers in China were organized by the Chinese Medical Association to participate in this study and 2297 patients were recruited between January 2004 and April 2006. BP assessments were made at four time points （daytime, evening, nighttime and morning） and polysomnography （PSG） was performed and subjects were classified into four groups by their apnea-hypopnea index （AHI）： control, n=213 with AHI 〈5; mild, n=420 with AHI -〉5 and 〈15; moderate, n=460 with AHI -〉15 and 〈30; and severe, n=1204 with AHI -〉30. SPSS 11.5 software package was used for statistical analysis and figure drawing. Results All the average daytime, nighttime, evening and morning BPs were positively correlated with AHI and negatively correlated with nadir nocturnal oxygen saturation. The ratios of nighttime/daytime and morning/evening average BP were positively correlated with AHI. The ratio of nighttime/daytime systolic BP became a ＂reversed BP dipping＂ pattern until the classification reached severe, while the ratio of nighttime/daytime diastolic BP became reversed at moderate. Similarly, the ratio of morning/evening diastolic BP becomes reversed even at mild. Conclusions OSAS may result in higher BP levels at all four time points. The ratios of nighttime/daytime and morning/evening BP increase with increased AHI. The increasing of diastolic BP, which is inclined to rise more quickly, is not parallel with increasing systolic BP.

Obstructive Sleep Apnea Syndrome is Associated with Metabolic Syndrome among Adolescents and Youth in Beijing： Data from Beijing Child and Adolescent Metabolic Syndrome Study

Background： Obstructive sleep apnea （OSA） syndrome has a negative impact on the health of millions of adolescents and youth. The aim of this study was to evaluate the associations of OSA syndrome with obesity and cardiometabolic risk factors among adolescents and youth at risk for metabolic syndrome （MS）.Methods： A total of 558 subjects aged 14-28 years were recruited from the Beijing Child and Adolescent Metabolic Syndrome Study. Each underwent a 2-h oral glucose tolerance test （OGTT）, echocardiography, and liver ultrasonography. Anthropometric measures, blood levels of glucose, lipids, and liver enzymes were assessed. Subjects with high or low risk for OSA were identified by Berlin Questionnaire （BQ）. Results： Among the subjects in obesity, 33.7% of whom were likely to have OSAby BQ. Subjects with high risk for OSA had higher neck and waist circumference and fat mass percentage compared to those with low risk for OSA （P 〈 0.001 ）. Moreover, significant differences in levels of lipids, glucose after OGTT, and liver enzymes, as well as echocardiographic parameters were found between the two groups with high or low risk for OSA （P 〈 0.05）. The rates of nonalcoholic fatty liver disease （71.0% vs. 24.2%）, MS （38.9% vs. 7.0%）, and its components in high-risk group were significantly higher than in low-risk group. Conclusions： The prevalence of OSA by BQ was high in obese adolescents and youth. A high risk for OSA indicates a high cardiometabolic risk. Mechanisms mediating the observed associations require further investigation.

Is obstructive sleep apnea syndrome a risk factor for pulmonary thromboembolism？

Background In many studies, obstructive sleep apnea （OSA） has been shown to be an independent risk factor for cardiovascular disease. Conversely, there are few reports establishing possible relation between OSA and venous thromboembolism （VTE）. In this study, the aim is to evaluate OSA via polysomnography in patients with pulmonary embolism and drawing the attention of clinicians to the presence of obstructive sleep apnea syndrome （OSAS） may be a risk factor for pulmonary embolism. Methods Fifty consecutive patients who were diagnosed with pulmonary embolism （PE） were evaluated prospectively for OSAS. Polysomnographic examination was conducted on 30 volunteer patients. The frequency of OSAS in PE was determined and PE cases were compared to each other after being divided into two groups based on the presence of a major risk factor. Results The study consisted of a total of 30 patients （14 females and 16 males）. In 56.7% of the patients （17/30）, OSAS was determined. The percent of cases with moderate and severe OSAS （apnea hipoapnea index 〉15） was 26.7% （8/30）. Patients who had pulmonary thromboembolism （PTE） without any known major VTE risk （n=20）, were compared to patients with VTE risk factors （n=10）, and significantly higher rates of OSAS were seen （70% and 30% respectively; P=0.045）. The mean age of the group with major PE risk factors was lower than the group without major PE risk factors （52 years old and 66 years old, respectively; P=0.015）, however, weight was greater in the group with major PE risk factors （88 kg and 81 kg, respectively; P=-0.025）. By multivariate Logistic regression analysis, in the group without any visible major risk factors, the only independent risk factor for PE was OSAS （P=0.049）. Conclusions In patients with PTE, OSA rates were much higher than in the general population. Moreover, the rate for patients with clinically significant moderate and severe OSA was quite high. PTE patients with OSA symptoms （not syndromes） and without known major risk factor should be examined for OSA. There seems to be a relationship between OSA and PTE. However, whether this relationship is a causal relationship or a relationship due to common risk factors or long-term complications of OSA is not clear. Further comprehensive studies on those special topics are needed to clarify these points.

Angiotensin Ⅰ-converting enzyme gene poly morphism in Chinese patientswith obstructive sleep apnea syndrome

Objective To investigate the relationship of an insertion/deletion (I/D) polymorphism of the angiotension converting enzyme (ACE) gene to obstructive sleep apnea syndrome (OSAS) patients and the control subjects.Methods Genomic DNA was extracted from blood samples and amplified by polymerase chain reaction (PCR). PCR primers flanked the polymorphic region in intro 16 of the ACE gene. Results OSAS patients had significantly higher frequencies of I/I genotype and insertion allele of the ACE gene as compared with the control subjects in Chinese population. The OSAS patients with I/I genotype had significantly longer apnea time, lower minimum SaO2 and greater AHI than the OSAS patients with I/D genotype. Conclusion These results indicate that the I/I genotype and I allele are a risk factor for OSAS in Chinese.

Retinal Vascular Morphological Changes in Patients with Extremely Severe Obstructive Sleep Apnea Syndrome

Background：Obstructive sleep apnea syndrome （OSAS） has been shown to generate hypertension and endothelial dysfunction.Retinal vessel is the only vessel that can be observed directly and noninvasively;retinal vascular abnormalities can serve as a predictive marker for the occurrence,clinical course,and prognosis of cardiovascular and cerebrovascular diseases.The objective of this study was to identify the effect of OSAS severity on the morphological changes of retinal vessels.Methods：Adult patients complained of snoring were included in this study.The patients＆#39; general information,polysomnography,and fundus photography parameters including central retinal artery equivalent （CRAE）,central retinal vein equivalent （CRVE）,and arteriole-to-venule ratio （AVR） were collected.Patients were divided into four groups according to their apnea-hypopnea index （AHI） results：Group Ⅰ,AHI ≤5/h;Group ll,5/h 〈 AHI ≤30/h;Group Ⅲll,30/h 〈 AHI ≤60/h;and Group Ⅳ,AHI 〉60/h.Results：A total of 133 patients were included in this study with 111 males （83.5%） and 22 females （16.5%）.Mean age was 41.6 ± 9.9 years,and the mean body mass index was 28.1 ± 4.0 kg/m2.AHI ranged between 0 and 130.8/h with a mean of 39.l ± 30.7/h.There were 24,34,35,and 40 patients in Group Ⅰ,Group Ⅱ,Group Ⅲ,and Group Ⅳ,respectively.Significant differences were found for AHI （F =388.368,P 〈 0.001）,minimal pulse oxygen saturation （F-91.902,P 〈 0.001）,and arousal index （F =31.014,P 〈 0.001） among four groups;no significant differences were found for CRAE （F=0.460,P =0.599） and CRVE （F =0.404,P =0.586） among groups;there were significant differences for AVR between Group l and Group Ⅳ （63.6 ± 5.1% vs.67.2 ± 5.5%,P =0.010） Group Ⅱ and Group Ⅳ （64.5 ± 6.0% vs.67.2 ± 5.5%,P =0.030）,and Group ll and Group Ⅳ （64.7 ± 4.1% vs.67.2 ± 5.5%,P=0.043）.A main group-by-AHI effect was found on the AVR：patients with higher AHI showed higher AVR results （r =0.225,P =0.009）.Multivariate logistic regression analysis was used for multi-variable factors.A group-by-age effect was found on the AVR：younger patients showed higher AVR results （β =-0.001,P =0.020）.Conclusions：This study indicated that increased AVR of retinal vessel can be observed in extremely severe OSAS patients.For patients with OSAS,retinal vascular abnormalities may become an early indication for further cardiovascular abnormalities.