The impact of OSA and CPAP treatment on cell adhesion molecules' night-morning variation.

PURPOSE: Obstructive sleep apnea (OSA) has been related to vascular inflammation and production of endothelial cell adhesion molecules (CAMs). We aimed to determine night-morning variation of CAMs in patients with OSA compared to controls and the effect of one-night continuous positive airway pressure (CPAP) treatment on them. METHODS: Nonsmoking men went through a full-attended polysomnography (PSG) study. Participants with moderate to severe OSA went through another PSG study while being treated with CPAP. Participants who did not have OSA composed the control group. Serum levels of intercellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1), and E-selectin were measured before and after sleep on both nights. RESULTS: Of 30 men, 20 had moderate to severe OSA while 10 did not. Night and morning ICAM-1 levels of patients with OSA were significantly higher than controls (p = 0.002 and p < 0.0001 respectively), while both night and morning VCAM-1 and E-selectin levels were not. Morning ICAM-1 levels of controls were significantly lower than night levels (p = 0.031), while morning ICAM-1, VCAM-1, and E-selectin levels of patients with OSA and morning VCAM-1 and E-selectin levels of controls were not. After CPAP treatment, the morning ICAM-1 levels, but not VCAM-1 levels, of patients with OSA were significantly lower than night levels (p = 0.006) and E-selectin levels showed a tendency for reduction (p = 0.06). CONCLUSIONS: OSA is associated with elevated night and morning ICAM-1 levels in adult men with OSA. Even one night of CPAP treatment restores the normal night-morning variation of ICAM-1 levels and may have an effect on E-selectin levels, as well.

The effect of continuous positive airway pressure therapy on blood pressure and arterial stiffness in hypertensive patients with obstructive sleep apnea.

AIM: We aimed to evaluate the effect of continuous positive airway pressure (CPAP) therapy on blood pressure (BP) and arterial stiffness in hypertensive patients with obstructive sleep apnea (OSA). PATIENTS AND METHODS: We studied 38 hypertensive patients who suffered from severe OSA. Ambulatory BP measurement was performed at baseline and after at least 3 months of uninterrupted CPAP therapy. In 19 of these patients, we also measured pulse wave velocity (PWV) at baseline, after the first night of CPAP therapy and at 3 months. Fifteen normotensive subjects without OSA comprised the control group. RESULTS: CPAP therapy reduced systolic BP from 141.5 ± 12.1 to 133.5 ± 9.7 mmHg (p = 0.007) and diastolic BP from 87.8 ± 6.8 to 83 ± 5.4 mmHg (p = 0.004). CPAP also reduced the PWV from 8.81 ± 1.4 to 8.18 ± 1 m/s after the first night of CPAP therapy (p = 0.003) and to 7.37 ± 1 m/s at 3 months (p = 0.007). CONCLUSIONS: To the best of our knowledge, this is the first study demonstrating that CPAP therapy in hypertensive patients with OSA improves arterial stiffness from the first night and that this favorable effect is maintained for at least 3 months of CPAP use. A reduction in BP was also observed, even though BP control was not always achieved.

Low-grade albuminuria in children with obstructive sleep apnea.

Small urinary protein loss (low-grade albuminuria or microalbuminuria) may reflect altered permeability of the glomerular filtration barrier. In the present study, it was hypothesized that children with obstructive sleep apnea have an increased risk of microalbuminuria compared with control subjects without sleep-disordered breathing. Albumin-to-creatinine ratio was measured in morning spot urine specimens collected from consecutive children with or without snoring who were referred for polysomnography. Three groups were studied: (i) control subjects (no snoring, apnea-hypopnea index < 1 episode h(-1) ; n = 31); (ii) mild obstructive sleep apnea (snoring, apnea-hypopnea index = 1-5 episodes h(-1) ; n = 71); and (iii) moderate-to-severe obstructive sleep apnea (snoring, apnea-hypopnea index > 5 episodes∙h(-1) ; n = 27). Indications for polysomnography in control subjects included nightmares, somnambulism and morning headaches. An albumin-to-creatinine ratio > median value in the control group (1.85 mg of albumin per g of creatinine) was defined as elevated. Logistic regression analysis revealed that children with moderate-to-severe obstructive sleep apnea, but not those with mild obstructive sleep apnea, had increased risk of elevated albumin-to-creatinine ratio relative to controls (reference) after adjustment for age, gender and presence of obesity: odds ratio 3.8 (95% confidence interval 1.1-12.6); P = 0.04 and 1.5 (0.6-3.7); P > 0.05, respectively. Oxygen desaturation of hemoglobin and respiratory arousal indices were significant predictors of albumin-to-creatinine ratio (r = 0.31, P = 0.01; and r = 0.43, P < 0.01, respectively). In conclusion, children with moderate-to-severe obstructive sleep apnea are at significantly higher risk of increased low-grade excretion of albumin in the morning urine as compared with control subjects without obstructive sleep apnea. These findings may reflect altered permeability of the glomerular filtration barrier related to nocturnal hypoxemia and sympathetic activation which are induced by obstructive sleep apnea.

Obstructive sleep apnoea syndrome promotes reversal albuminuria during sleep.

INTRODUCTION: Sleep apnoea syndrome (OSAS) may induce albuminuria during sleep which could reflect one of the possible pathogenetic mechanisms regarding cardiovascular risk. MATERIALS AND METHODS: We studied 224 patients with newly diagnosed OSAS, free of any chronic disease, and any regular drug therapy. The levels of urine albumin/creatinine ratio (ACR) before (ACR-bsleep) and immediately after (ACR-asleep) a sleep study were determined. The same procedure was repeated during the first night on CPAP treatment (n = 121) and in 46 reevaluated patients, after 3 months, on CPAP therapy. Ambulatory blood pressure was monitored in 133 of the patients. RESULTS: ACR-asleep was significantly higher in patients (17.82 ± 31.10 mg/g) compared with controls (6.54 ± 6.53 mg/g, p < 0.001). The mean percent change in ACR levels between after and before sleep (%dACR) was increased by 8.82% ± 61.06 in OSAS patients and reduced by 26.87% ± 18.95 in controls (p < 0.001). During the first sleep study on CPAP, the %dACR was reduced by 21.40% ± 24.59, in contrast to the increase observed during the initial study (10.73% ± 69.93, p < 0.001). This beneficial effect of CPAP treatment was preserved in the reevaluated patients. The %dACR was +29.33% ± 57.67 in nondippers (44% of the patients) and -5.57% ± 40.81 in dippers (p < 0.001). It was negatively correlated to the percent change of systolic (rho = -0.284, p = 0.003) and diastolic (rho = -0.341, p < 0.001) blood pressure between wakefulness and sleep. Contrary to normal people, ACR is increased in OSAS patients during sleep, at least partially, related to the nondipping phenomenon observed in these patients. Following CPAP treatment, urinary albumin excretion is reduced.

Sleep apnea syndrome, inflammation and oxidative stress in hemodialysis patients.

INTRODUCTION: Sleep apnea syndrome (SAS) is an established cardiovascular risk factor in the general population related to inflammation and oxidative stress and is very common among hemodialysis patients. Cardiovascular disease and its complications is the main cause of death among hemodialysis patients. The aim of the present study was to investigate the role of SAS in the promotion of inflammation and oxidative stress and thus in the augmentation of cardiovascular risk in hemodialysis patients. METHODS: Thirty-seven hemodialysis patients underwent an overnight full polysomnography study. The following morning blood samples were obtained and TNF-α (tumor necrosis factor-α), IL-6 (interleukin-6), MPO (myeloperoxidase), and oxLDL (oxidized low density lipoprotein) were measured. FINDINGS: We investigated the correlation of patients' markers of inflammation and oxidative stress with their sleep parameters (total sleep time, AHI, apnea/hypopnea index; RDI, respiratory disturbance index; DI, desaturation index, mean and minimum SpO2 and percentage of sleep time with SpO2 < 90%). TNF-α correlated positively with BMI (r = 0.510, P < 0.0001) and total sleep time (r = 0.370, P = 0.027). IL-6 correlated positively with age (r = 0.363, P = 0.027), AHI (r = 0.385, P = 0.018), DI (r = 0.336, P = 0.042) and percentage of sleep time with SpO2 < 90% (r = 0.415, P = 0.012) and negatively with mean SpO2 (r = -0.364, P = 0.027). Myeloperoxidase correlated positively with AHI (r = 0.385, P = 0.018), DI (r = 0.380, P = 0.02) and percentage of sleep time with SpO2 < 90% (r = 0.388, P = 0.019). Finally, oxLDL correlated positively with BMI (r = 0.443, P = 0.007), AHI (r = 0.395, P = 0.015), RDI (r = 0.328, P = 0.048) and total sleep time with SpO2 <90% (r = 0.389, P = 0.019). CONCLUSIONS: These results indicate that, in hemodialysis patients, the severity of SAS and nocturnal hypoxia correlated positively with markers of inflammation and oxidative stress.

Inspiration during the sleep stages without and after preceding exercise, as a factor supporting circulation of blood and the "resting procedure".

UNLABELLED: In a previous preliminary work we found a longer inspiration than expiration period during sleep, opposite to what normally happens during wakefulness. These results which derived from quite a few measurements, but only from two male subjects, were not categorized to sleep stages. In the present paper we have studied the heart rate/minute, the respiration rate/minute and also the duration of inspiration and expiration (respiration ratio), in six healthy subjects, four men and two women aged 23-42, in all four stages of sleep, the REM stage and in arousals. These parameters were studied in the same subjects twice, once after a resting pre-sleep period (sleep A) and another time after "exercise" before going to sleep (sleep B), in an attempt to trace any changes in the above parameters that could be related to the "resting procedure". "Exercise" before sleep B consisted of a heavy dinner taken after 21:30 h and some physical activity. Results were analyzed by the Wilcoxon non-parametric tests. The differences between sexes were analyzed by the Mann-Whitney, two independent samples, test and have shown the following: a) The heart rate and the respiration rate did not increase significantly in sleep B as compared to sleep A in most of the sleep stages and arousals. b) Respiration ratio did not change significantly between sleep A and sleep B. c) We have confirmed our previous finding that during sleep, the mean values of inspiration are longer than those of expiration and have also shown that the increase in the duration of inspiration as indicated by the respiration ratio, existed in all four stages of sleep, the REM and the arousal periods. d) Significantly higher heart rate and respiration rate and lower respiration ratio were observed in women as compared to men, throughout the study and especially during sleep B as compared to sleep A. This finding, although statistically acceptable, needs confirmation due to the small number of women studied. e) Statistical analysis by the Wilcoxon test of the accumulated means of all sleep A and B stages in heart rate, respiratory rate and respiration ratio were compared with the same findings during arousal periods and showed no significant difference except for stage 1 sleep B (P=0.002). f) The action of inspiration inducing a negative pressure in the thorax and altering the intra-abdominal pressure may be considered an "elastic" action supporting blood flow and contributing to the "resting procedure" during sleep. IN CONCLUSION: (a) The results a) and b) indicate that in the young subjects studied, the "exercise" they had before sleep B was not sufficient to significantly modify the above parameters. (b) The "arousal" period, according to the above findings, may be considered as part of the usual sleeping period. (c) Women as compared to men had higher heart rate and respiration rate and lower respiration ratio, especially in sleep B as compared to sleep A. This result needs confirmation. (d) We found increased duration of inspiration during sleep. As reminded above, inspiration has favorable hemodynamic action in the thorax, delivers oxygen to the heart and body tissues and exercises an elastic action to the abdominal vessels. Having all these in mind, inspiration may be considered as a factor supporting the circulation of blood and the "resting procedure" during sleep.

Evaluation of five different questionnaires for assessing sleep apnea syndrome in a sleep clinic.

BACKGROUND: Obstructive sleep apnea/hypopnea syndrome (OSAHS) is a major cause of morbidity and mortality. Different clinical models and questionnaires have been used to evaluate patients with the highest OSAHS probability. OBJECTIVES: To evaluate the clinical utility of five different questionnaires--STOP, STOPBang (SB), Berlin Questionnaire (BQ), Epworth Sleepiness Scale (ESS), and 4-Variable Screening Tool (4-V) - in a sleep clinic in order to identify patients at risk for OSAHS and to assess the best possible combination of these tools. METHODS: 1853 (74.4% males) patients (mean age 52±14 years; mean body mass index 32.8±7 kg/m2) visiting a sleep clinic were studied retrospectively. RESULTS: SB had the highest sensitivity (97.6%), the largest area under the receiver operating characteristics curve (AUC) (0.73; 95% CI, 0.7-0.76) and best OR (5.9; 95% CI, 3.6-9.5), but the lowest specificity (12.7%) for AHI > or =15. The 4-V > or = 14 had the highest specificity (74.4%) followed by ESS (67%). BQ had good sensitivity (87%), worse specificity (33%) than 4-V and ESS but better than STOP (13%) and SB (12.7%). The combination of questionnaires did not improve their predictive value. CONCLUSIONS: SB had the highest sensitivity, OR, and AUC, but rather low specificity, and 4-V the highest specificity. The combination of different questionnaires did not improve their predictive value.