Subclinical left ventricular myocardial dysfunction in patients with obstructive sleep apnea syndrome: insights from noninvasive left ventricular myocardial work analysis.

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) is associated with various cardiovascular diseases and has aroused public concern. Early detection for declining myocardial function is of great significance. This study was aimed at noninvasively evaluating the subclinical left ventricular (LV) myocardial dysfunction with LV pressure-strain loop (PSL) in patients with OSAS having normal LV ejection fraction. METHODS: We enrolled 200 patients with OSAS who visited the Beijing Chaoyang Hospital between February 2021 and December 2021. According to the apnea-hypopnea index (AHI), patients were divided into mild, moderate, and severe groups. The global longitudinal strain (GLS) of the left ventricle was analyzed by two-dimensional speckle tracking echocardiography. The LV PSL was used to assess global work index (GWI), global constructive work (GCW), global waste work (GWW), and global work efficiency (GWE), and comparisons were made among groups. RESULTS: GLS was significantly lower in the severe group than in mild and moderate group. GWI, GCW, and GWE were lower in the severe group than in mild and moderate groups. GWW was significantly higher in the severe group than in the mild group. GLS, GWI, and GWE were moderately correlated with AHI (Spearman's ρ = -0.468, -0.321, and -0.319, respectively; P < 0.001), whereas GCW and GWW showed a weak correlation with AHI (Spearman's ρ = -0.226 and 0.255 respectively; P < 0.001). Multiple regression analyses revealed AHI was independently associated with GWI after adjusting for SBP, GLS, e', etc. AHI was independently associated with GCW after adjusting for SBP, GLS, etc. CONCLUSIONS: The LV PSL is a new technique to noninvasively detect myocardial function deterioration in patients with OSAS and preserved LV ejection fraction. Increased severity of OSAS was independent associated with both decreased GWI and GCW.

Characterization of fecal metabolome changes in patients with obstructive sleep apnea.

STUDY OBJECTIVES: Obstructive sleep apnea (OSA) is a clinical syndrome characterized by recurrent episodes of apnea or hypopnea of the upper airway, leading to increased negative intrathoracic pressure, sleep fragmentation, intermittent hypoxia during sleep, and increased risk for morbidity and mortality of affected patients. The gut microbiome plays a key role in OSA pathogenesis, and fecal metabolic profiling reflects the gut microbial functional readout and mediates host-microbiome interactions. METHODS: Herein, we conducted a cohort study to explore fecal metabolic signatures distinguishing OSA (44 patients) from healthy controls (22 healthy controls) by untargeted gas chromatography-time-of-flight mass spectroscopy. RESULTS: Significant metabolic signatures were detected in stool samples of patients with OSA: 246 metabolites of 24 ontology classes were identified, and 48 metabolites of 6 ontology classes were shifted. An enrichment of arachidonic acid, docosahexaenoic acid, and 11Z-eicosenoic acid and reduction in stearic acid, 5-hydroxyindoleacetic acid, gluconic acid, and α-hyodeoxycholic acid were observed in stool samples from patients with OSA. Fecal variance resulted in alterations in potential metabolic activities and was thereby strongly associated with host phenotypes, such as pulse blood oxygen saturation and apnea-hypopnea index. The prediction model based on feces metabolomics was established to distinguish OSA from healthy controls with high accuracy. CONCLUSIONS: This study revealed the metabolomic signatures of patients with OSA in feces, and the findings provide evidence of an association between metabolome and OSA. CITATION: Dong Y, Wang P, Lin J, et al. Characterization of fecal metabolome changes in patients with obstructive sleep apnea. J Clin Sleep Med. 2022;18(2):575-586.

Anxiety and depression in patients with chronic obstructive pulmonary disease and obstructive sleep apnea: the overlap syndrome.

PURPOSE: Psychological symptoms are increasingly being noted in patients with chronic diseases. Currently, little evidence is available on the mental health of patients with overlap syndrome (OVS, chronic obstructive pulmonary disease plus obstructive sleep apnea). This study aimed to describe the prevalence and identify influencing factors of anxiety and depression in patients with OVS. METHODS: We recruited patients admitted for chronic obstructive pulmonary disease (COPD) from July 2018 to July 2019 who also underwent polysomnography tests to assess obstructive sleep apnea (OSA). COPD patients who had an apnea-hypopnea index (AHI) ≥ 5/h were defined as OVS. COPD patients who had an AHI < 5/h were identified as pure COPD. Questionnaires were administered to evaluate depression and anxiety in all subjects. We compared the differences in scores between patients with OVS and pure COPD. RESULTS: Two hundred and fifty-two patients were included, 180 (71%) patients had OVS, while only 72 patients had pure COPD. In the OVS group, 54% of the patients had depression, and 77% of the patients had anxiety. We found that patients with OVS had higher anxiety (8.00 (4.00, 10.00) vs. 6.00 (3.00, 9.00), p = 0.018) and depression (8.00 (4.00, 10.00) vs. 5.50 (2.25, 10.00), p = 0.022) scores than patients with pure COPD. A higher proportion of patients with hypertension (41% vs. 21%) and coronary heart disease (14% vs. 4%) were found in the OVS group. Chest pain, COPD Assessment Test (CAT) score, and OVS were independent risk factors for depression (P<0.05). A positive correlation was shown between anxiety and depression (r=0.638, p < 0.001). CONCLUSIONS: Anxiety and depression were more severe in patients with OVS than in patients with pure COPD. More attention should be paid to the mental health of OVS patients. TRIAL REGISTRATION: ClinicalTrials.gov; URL: www. CLINICALTRIALS: gov . NO.: NCT03182309. Registered on June 9, 2017; https://clinicaltrials.gov/ct2/show/NCT03182309?term=NCT+03182309&draw=2&rank=1.

Risk factors and fraction of exhaled nitric oxide in obstructive sleep apnea in adults.

OBJECTIVE: This study aimed to evaluate the relationship between obstructive sleep apnea (OSA) and the fraction of exhaled nitric oxide (FENO), and to assess the effect of risk factors of airway inflammation on OSA. METHODS: Medical records of patients in the Respiratory Sleep Center at Chao-Yang Hospital in Beijing between January 2015 and June 2017 were analyzed. All patients were diagnosed with OSA. Data of the medical history, clinical examinations, FENO, and upper airway computed tomographic findings were collected. Logistic regression was used to evaluate risk factors of OSA. RESULTS: A total of 181 patients were admitted to the Respiratory Sleep Center during the study and 170 had a diagnosis of OSA and were included in the study. Single factor analysis showed that male sex, age, body mass index, smoking index, alcohol consumption, FENO, soft palate thickness, soft palate length, the narrowest transverse diameter of the upper airway, tonsil size, and nasal sinusitis were risk factors for sleep-disordered breathing and disease severity. CONCLUSIONS: Male sex, age, body mass index, FENO, the narrowest transverse diameter of the upper airway, and normal tonsil size are associated with OSA and disease severity. The severity of OSA is associated with FENO levels.

Effect of lung function on the apnea-hypopnea index in patients with overlap syndrome: a multicenter cross-sectional study.

PURPOSE: Patients with chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) are referred to as having overlap syndrome (OVS). However, the relationship of lung function with the apnea-hypopnea index (AHI) in patients with OVS has not been evaluated. This multicenter study aimed to evaluate the relationship. METHODS: COPD patients diagnosed by spirometry were recruited from four Chinese tertiary hospitals. Those patients were requested to attend an overnight polysomnography (PSG). The relationships between parameters of lung function and sleep respiration in patients with OVS were assessed using multiple regression analyses. RESULTS: A total of 520 OVS patients and 246 patients with COPD only finally met inclusion criteria for study. After adjustment for age, sex, body mass index, neck circumference, economic status, smoking status, alcohol consumption, and hypertension, the forced expiratory volume in the first second (FEV1) had a positive correlation with the AHI in patients with OVS (ß, 0.17; 95% CI, 0.06-0.28; P < 0.01). However, when the severity of lung function of patients with OVS was stratified, the correlation with the FEV1 of each grade and the AHI was absent (P > 0.05). Additionally, The FEV1 was positively correlated with the nadir oxygen saturation (SaO2) (ß, 0.18; 95% CI, 0.08-0.27; P < 0.01) and was negatively correlated with the percentage of time spent with an SaO2 below 90% (TS90%) (ß,- 0.41; 95% CI,- 0.61-0.21; P < 0.01) in patients with OVS using multiple regression analyses. CONCLUSION: Lung function was associated with the AHI in patients with OVS. The lower FEV1 may play some protective role in the severity of AHI in OVS patients. Trial registry ClinicalTrials.gov , No.: NCT03182309, URL: www.clinicaltrials.gov .

[Impaired glucose metabolism in patients with obstructive sleep apnea hypopnea syndrome].

OBJECTIVE: To investigate the prevalence of impaired glucose-insulin metabolism in obstructive sleep apnea hypopnea syndrome (OSAHS); to examine the relation between severity of OSAHS and impaired glucose metabolism; and to evaluate the effectiveness of continuous positive airway pressure (CPAP) on impaired glucose metabolism. METHODS: A total of 214 patients who were free of diabetes at baseline underwent both nocturnal polysomnography (PSG), and 2-h oral glucose-tolerance test, insulin and hemoglobin A1c test. CPAP treatment for glucose-insulin metabolism (+) was given to OSAHS group after informed consent had been obtained. RESULTS: Eighty-eight patients and 17 patients with impaired glucose-insulin metabolism were found in OSAHS group and the control group respectively. Impaired glucose-insulin metabolism was present in 54.3% of OSAHS group and 32.7% of control group. Logistic regression analysis showed a significant positive correlation with OSAHS (AHI ≥ 10 times/h) and impaired glucose-insulin metabolism in all patients (OR = 2.440, 95%CI 1.201 - 4.958). Plasma glucose level changes had no significant differences between before and after CPAP treatment (P > 0.05). CONCLUSION: OSAHS is associated with a high frequency of impaired glucose metabolism. The relationship between OSAHS and impaired glucose metabolism is independent of obesity. Longest apnea time (LAT) and AHI are important contributors to impaired glucose metabolism in OSAHS patients. Short-term CPAP therapy has no significant improvement on glucose metabolism in patients with OSAHS.

[The relation between obstructive sleep apnea hypopnea syndrome and the severity of coronary atherosclerosis in coronary artery disease].

OBJECTIVE: To investigate the relation between obstructive sleep apnea hypopnea syndrome (OSAHS) and the Gensini score, which is given to define the severity of coronary atherosclerosis, based on coronary angiograms findings, in patients with coronary artery disease. METHODS: We examined the apnea hypopnea index (AHI) using polysomnography (PSG) in 231 consecutive patients with coronary artery disease (ejection fraction, > 40%) that was diagnosed by coronary angiography, 160 patients with angina pectoris and 71 patients with myocardial infarction. The Gensini score was calculated for each patient from the coronary arteriogram. The patients were classified into the following four groups according to the AHI, serious group: AHI > 40 events per hour, 44 patients; moderate group: 20 events per hour < AHI < or = 40 events per hour, 67 patients; mild group: 10 events per hour < or = AHI < or = 20 events per hour, 57 patients; OSAHS (-) group: AHI < 10 events per hour, 63 patients. Then the groups were examined for the relation between the AHI and the Gensini score. RESULTS: Of the total number of patients, 72. 72% (168/231) had an AHI of more than ten per hour. The prevalence of multivessel disease ( > or = 3 vessels) was 75.00% (33/44)in serious group, 61.12% (41/67)in moderate group, 38.60% (22/57) in mild group, and 30.16% (19/63) in OSAHS(-) group. The Gensini score was significantly higher in serious group than the other three groups. The Gensini score was higher in moderate group than mild group and OSAHS (-) group, and the Gensini score in mild group was higher than that in OSAHS (-) group. The Gensini score showed a significant positive correlation with the AHI (r = 0.561, P < 0.001) in all patients. Multiple regression analysis showed that AHI was the most significant, independent determinant of the Gensini score among the coronary risk factors tested, and that it explained 31.4% of the variances. CONCLUSION: These findings suggest that AHI which is used to assess the severity of OSAHS is an important contributor to coronary atherosclerosis in the patients with cardiovascular disease, and the patients with more serious OSAHS would have more serious and complex coronary artery lesions.

[The changes of respiratory mechanics in patients with obstructive sleep apnea-hypopnea syndrome during sleep].

OBJECTIVE: To study the changes of respiratory mechanics in patients with obstructive sleep apnea hypopnea syndrome (OSAHS) during sleep. METHODS: Eighty-one consecutive subjects, 70 males and 11 females, mean age (43.9 +/- 12.6), were recruited in this study. The respiratory mechanics during sleep were studied by using the side stream spirmeter (SSS) technique. All subjects underwent respiratory mechanics monitoring with Novametrix Medical Systems (connected with full face mask) during nocturnal polysomnographic (PSG) study. Then by the apnea-hypopnea index (AHI), the subjects were divided into the OSAHS group (AHI >or= 15/h) and the control group (AHI < 15/h). RESULTS: Fifty-four subjects were confirmed to have OSAHS [AHI = (57.6 +/- 24.9) h] by PSG, and 27 as the control group [AHI = (4.4 +/- 4.1) h]. In the OSAHS group, inspiratory tidal volume/expiratory tidal volume (V TI/V TE) was 1.37 +/- 0.18 during the first respiratory cycle after apnea, which was significantly greater than that (0.99 +/- 0.04) during wakefulness. The mean V TI/V TE (0.86 +/- 0.09) during the 5 respiratory cycles and that (0.72 +/- 0.19) of the last respiratory cycle before the next apnea decreased significantly. These indicated that the functional residual capacity (FRC) and upper airway size were reduced gradually before apnea. Compared with the measurements before sleep, V TI [(463 +/- 122) ml vs (554 +/- 134) ml], V TE [(466 +/- 127) ml vs (565 +/- 147) ml], and expired minute volume [(6.4 +/- 1.6) L/min vs (8.3 +/- 1.9) L/min] were decreased significantly during light sleep without apnea. Tidal breath flow-volume loop showed that in the OSAHS group, the inspiratory resistance increased in 54 patients (100%), the expiratory resistance increased in 52 (96.3%), and both of them increased in 52 (96.3%). CONCLUSIONS: OSAHS patients exhaled more air than inhaled gradually before apnea onset, and then this change was compensated by inhaling more air than exhaled in the first respiratory cycle following apnea. These resulted in decreases in FRC and upper airway size, which may play an important role in the pathophsiological mechanisms of sleep apnea. The tidal volume decrease suggested that the breathing drive was reduced in light sleep of OSAHS. In addition, a rise of both inspiratory and expiratory resistance was evident in a majority of patients with OSAHS.

[Pharyngeal size and collapsibility in patients with obstructive sleep apnea hypopnea syndrome].

OBJECTIVE: To study the pharyngeal cross-sectional area and collapsibility among the patients with obstructive sleep apnea hypopnea syndrome (OSAHS), simple snorers, and normal persons. METHODS: 171 patients with OSAHS, 44 with mild, 51 with moderate, and 56 with severe OSAHS, 47 simple snorers, and 47 healthy subjects underwent upper airway cross-sectional area measurement using acoustic pharyngometer at the conditions of functional residual capacity (FRC) and residual volume (RV) in the upright sitting position. RESULTS: When the lung volume decreased from the condition of FRC to the condition of RV the pharyngeal cross-sectional area decreased from 2.63 cm(2) +/- 0.42 cm(2) to 1.96 cm(2) +/- 0.35 cm(2) for the simple snorers, 2.70 cm(2) +/- 0.44 cm(2) to 1.78 cm(2) +/- 0.39 cm(2) for the mild OSAHS patients, from 2.62 cm(2) +/- 0.52 cm(2) to 1.79 cm(2) +/- 0.37 cm(2) for the moderate OSAHS patients, and from 2.57 cm(2) +/- 0.46 cm(2) to 1.75 cm(2) +/- 0.40 cm(2) for the severe OSAHS patients, all with higher decrease rates (33.93% +/- 11.81%, 31.13% +/- 10.76%, and 31.31% +/- 13.44%) than that of the normal persons (25.07% +/- 10.39%), smaller than that for the normal persons (21.11% +/- 8.19%, from 3.05 cm(2) +/- 0.6 cm(2) to 2.38 cm(2) +/- 0. 47 cm(2), all P < 0.05). The change ratios of the 3 OSAHS groups were significantly higher than that of the simple snorer group (all P < 0.01). This indicated that the pharynges of OSAHS patients were more collapsible. CONCLUSION: Snorers with or without apnea have smaller pharyngeal cross-sectional area than nonsnorers. The collapsibility of the upper airway is greater in both OSHAS patients and simple snorers than in healthy subjects.