Mild Obstructive Sleep Apnea Group Research Articles

Relationship Between Snoring Intensity and Severity of Obstructive Sleep Apnea.

ObjectivesThe aim of this study was to determine the relationship between the intensity of snoring and severity of sleep apnea using Watch-PAT (peripheral arterial tone) 100.MethodsA total of 404 patients (338 males and 66 females) who underwent home-based portable sleep study using Watch-PAT 100 for obstructive sleep apnea (OSA) from January 2009 through December 2011 were included in this study. Subjects were divided into 4 groups; no OSA (PAT apnea hypopnea index [pAHI]<5/hour), mild OSA (5≤pAHI<15/hour), moderate OSA (15≤pAHI<30/hour), or severe OSA groups (pAHI≥30/hour). Mean snoring intensity and percent sleep time with snoring intensity greater than 40, 50, and 60 dB were measured by Watch-PAT 100. Correlations of these parameters with apnea hypopnea index (AHI), respiratory disturbance index (RDI), and oxygen desaturation index were assessed.ResultsThe mean age and body mass index were 46.5±14.8 years and 24.7±3.4 kg/m2, respectively. Mean AHI and RDI were 16.5±15.3/hour and 20.8±14.3/hour, respectively. The mean snoring intensity in the no, mild, moderate, and severe OSA groups was 44.0±2.7, 45.4±6.0, 47.7±5.0, and 50.5±5.6 dB, respectively (P<0.001). There was a positive correlation between snoring intensity and pAHI or PAT RDI (pRDI) (r=0.391 and r=0.385, respectively, both P<0.001). There was also a positive correlation between percent sleep time with the snoring intensity greater than 50 dB and pAHI or pRDI (r=0.423 and r=0.411, respectively, both P<0.001).ConclusionThis study revealed that the intensity of snoring increased with the severity of sleep apnea, which suggests that the loudness of snoring might be an indicator of the severity of OSA.

Vibration signals of snoring as a simple severity predictor for obstructive sleep apnea.

Polysomnography (PSG), which involves simultaneous monitoring of various physiological monitors, is the current comprehensive tool for diagnosing obstructive sleep apnea (OSA). We aimed at validating vibrating signals of snoring as a single physiological parameter for screening and evaluating severity of OSA. Totally, 111 subjects from the sleep center of a tertiary referral center were categorized into four groups according to the apnea hypopnea index (AHI) obtained from PSG: simple snoring group (5 > AHI, healthy subjects, n = 11), mild OSA group (5 ≤ AHI < 15, n = 11), moderate OSA group (15 ≤ AHI < 30, n = 30) and severe OSA group (AHI ≥ 30, n = 59). Anthropometric parameters and sleep efficiency of all subjects were compared. Frequencies of amplitude changes of vibrating signals on anterior neck during sleep were analyzed to acquire a snoring burst index (SBI) using a novel algorithm. Data were compared with AHI and index of arterial oxygen saturation (Δ Index). There were no significant differences in age and sleep efficiency among all groups. Bland-Altman analysis showed better agreement between SBI and AHI (r = 0.906, P < 0.001) than Δ Index and AHI (r = 0.859, P < 0.001). Additionally, receiver operating characteristic (ROC) showed substantially stronger sensitivity and specificity of SBI in distinguishing between patients with moderate and severe OSA compared with Δ Index (sensitivity: 81.4% vs 66.4%; specificity: 96.7% vs 86.7%, for SBI and Δ Index, respectively). SBI may serve as a portable tool for screening patients and assessing OSA severity in a non-hospital setting.

Mild obstructive sleep apnea: beyond the AHI

A common conundrum faced by sleep medicine practitioners is how to manage the large group of patients with mild sleep apnea. Many patients are referred for sleep evaluation, with symptoms thought to be due to obstructive sleep apnea (OSA). Often polysomnography demonstrates only mild sleep apnea, and the clinician and patient are faced with the dilemma of whether to use continuous positive airway pressure (CPAP) therapy or an oral appliance. In making this important decision the clinician incorporates the commonly used definition of mild sleep apnea as an apnea-hypopnea index of between 5 and 14 apneas or hypopneas per hour of sleep. Moderate sleep apnea is defined as 15-29 events per hour, and severe is 30 and above events per hour. These arbitrary thresholds originated in the early 1980s when knowledge of this condition was in its infancy and little was known about the long term health effects. The definition was based on the finding of apneas, defined by the complete cessation of airflow for at least 10 seconds. The concept of hypopnea and respiratory-effort related arousal (RERA) came later and with frequently changing definitions that have been the subject of significant controversy throughout the last 30 years. Many sleep centers include these RERA’s in the definition of respiratory disturbance index, which is incorrectly used interchangeably with AHI. While the sleep literature has demonstrated the untoward effects of moderate to severe sleep apnea, there has been considerable debate about the clinical significance of mild sleep apnea, that is, an AHI between 5 and 15. The current paper by Quan, et al (1) is a significant contribution to the literature in sleep medicine addressing this important clinical question. This paper reports data drawn from the APPLES study, a large multi-center, well-conducted study designed to determine if CPAP therapy improves sleepiness, mood disorder, or cognitive function in patients with OSA, that has subsequently produced several important publications (2-6). As part of the study, extensive data was obtained on each of these neurocognitive parameters including the Epworth Sleepiness Scale, Stanford Sleepiness Scale, Hamilton Rating Scale for Depression, Profile of Mood States, and Sleep Apnea Quality of Life Index, all validated questionnaires used frequently in the sleep literature. In this part of the study, 199 patients with an AHI>5 but <15 were compared to 40 patients enrolled in the study, but with and AHI<5. The mean AHI was 10 per hour in the mild OSA group, and was 3 per hour in the non-OSA group. Size of the study was statistically large enough to determine significant differences. Remarkably, there

Uric Acid as a Potential Mediator of Cardiovascular Morbidity in Obstructive Sleep Apnea Syndrome

Abstract Background and aims Obstructive sleep apnea (OSA) is now considered as an independent risk factor for cardiovascular (CV) disease. Although uric acid is increasingly being implicated in CV morbidity and mortality, no study attempted to determine independent role of uric acid in CV morbidity of OSA patients. We aimed to assess the role of serum uric acid as a potential mechanism of CV morbidity in a nonselected cohort of OSA patients. Methods This was a cohort study in which patients who had undergone a formal sleep study for diagnosis of OSA were recruited. Included patients were grouped according to apnea–hypopnea index (AHI) as mild, moderate and severe OSA. Patients with AHI Results 436 OSA patients included (72 controls, 97 with mild, 75 with moderate, and 192 with severe OSA). The severe group also had higher serum uric acid level compared with the control and other OSA groups. Linear regression showed that the Ln uric acid was positively associated with Ln AHI score. In unadjusted logistic regression, severe OSA was associated with higher odds of a cardiovascular event, OR = 2.81 (1.307–6.041), p = 0.0081 while the other categories of sleep apnea were not. However, severe OSA was no longer significant after adjusting for age, gender, diabetes mellitus status, hypertension status, BMI, and smoking, OR = 1.882 (0.826–4.287), p = 0.1322. Uric acid was significantly higher in those who had a cardiovascular event even in the mild, moderate and severe OSA groups. Conclusion Hyperuricemia is strongly associated with cardiovascular disease in OSA patients. This strong relationship persists even after controlling for well-known traditional risk factors for cardiovascular disease.

Severity of obstructive sleep apnea is associated with elevated plasma fibrinogen in otherwise healthy patients

Obstructive sleep apnea (OSA) has been implicated in both cardiovascular and cerebrovascular diseases. Systemic inflammation and coagulation may be related to cardiovascular pathophysiology in patients with OSA. Fibrinogen is a major coagulation protein associated with inflammation, and long-term elevated plasma fibrinogen is associated with an increased risk of major cardiovascular diseases. We assessed whether severity of OSA is associated with levels of fibrinogen in newly diagnosed, untreated, and otherwise healthy OSA patients. We studied 36 men with OSA and 18 male control subjects (apnea-hypopnea index [AHI]<5 events/h). OSA patients were divided into mild (AHI≥5<15 events/h) and severe (AHI≥15 events/h) OSA groups. Morning fibrinogen levels in OSA patients were compared to those in control subjects of similar age, body mass index, blood pressure, smoking habits, and alcohol consumption. Fibrinogen levels were significantly elevated in patients with severe OSA compared to both control (P=0.003) and mild OSA (P=0.02) subjects after adjustment for covariates. However, there were no significant differences in fibrinogen levels between mild OSA and control subjects. Fibrinogen levels were directly related to AHI and arousal index and inversely related to mean and lowest oxygen saturation during sleep. Severity of OSA was associated with increased fibrinogen level independent of other factors, suggesting that apneic events and oxygen desaturation during sleep are mechanisms for increased fibrinogen levels in patients with OSA.

Gender‐Related Changes of the Epicardial Fat Thickness and Leptin in Obstructive Sleep Apnea

Epicardial fat thickness (EFT), an indicator of visceral obesity, and leptin are 2 novel markers for studying the obstructive sleep apnea (OSA) population. This study aimed to investigate the effects of gender on leptin levels and EFT, and the relation with OSA severity. A total of 149 patients with OSA (female/male 55/94 and mean age 50.8 ± 9.2 years) and 50 control patients (female/male 24/26 and mean age 48.9 ± 8.8 years) were included in the study. The study population was divided into 4 groups according to apnea/hypopnea index (AHI) as control (AHI <5), the mild OSA (AHI 5-14), the moderate OSA (AHI 15-29), and the severe OSA (AHI ≥30). EFT was obtained from parasternal long-axis and parasternal short-axis echocardiographic images. Leptin levels among females were significantly higher than among males (10.5 [7.8] vs. 5.4 [4.5] ng/mL, P = 0.001, respectively). Among women, leptin levels were significantly higher in the severe OSA group compared to the control group (9.8 [9.0] vs. 15.5 [10.1] ng/mL, P = 0.05, respectively). Conversely, no relation was observed between OSA severity and the leptin levels among men. EFT was not significantly different between the 2 genders (P > 0.05). EFT was thicker in the severe OSA group than in the control and mild OSA groups among women, whereas EFT was not changed according to OSA severity among males (P > 0.05). Leptin and EFT may be a valuable parameter in the evaluation of OSA severity in women than in men.

Mortality in middle-aged men with obstructive sleep apnea in Finland

Obstructive sleep apnea (OSA) has been associated with an elevated rate of cardiovascular mortality. However, this issue has not been investigated in patients with elevated proneness to cardiovascular diseases. Our hypothesis was that OSA would have an especially adverse effect on the risk of cardiovascular mortality in Finnish individuals exhibiting elevated proneness for coronary heart diseases. Ambulatory polygraphic recordings from 405 men having suspected OSA were retrospectively analyzed. The patients were categorized regarding sleep disordered breathing into a normal group (apnea hypopnea index (AHI) < 5, n = 104), mild OSA group (5 ≤ AHI < 15, n = 100), and moderate to severe OSA group (AHI ≥ 15, n = 201). In addition, basic anthropometric and health data were collected. In patients who died during the follow-up period (at least 12 years and 10 months), the primary and secondary causes of death were recorded. After adjustment for age, BMI, and smoking, the patients with moderate to severe OSA suffered significantly (p < 0.05) higher mortality (hazard ratio 3.13) than their counterparts with normal recordings. The overall mortality in the moderate to severe OSA group was 26.4 %, while in the normal group it was 9.7 %. Hazard ratio for cardiovascular mortality was 4.04 in the moderate to severe OSA and 1.87 in the mild OSA group. OSA seems to have an especially adverse effect on the cardiovascular mortality of patients with an elevated genetic susceptibility to coronary heart diseases. When considering that all our patients had possibility of continuous positive airway pressure treatment and our reference group consisted of patients suffering from daytime somnolence, the hazard ratio of 4.04 for cardiovascular mortality in patients with moderate to severe disease is disturbingly high.

Levels of neuroglobin in serum and neurocognitive impairments in Chinese patients with obstructive sleep apnea

The impact of different severities of obstructive sleep apnea (OSA) on cognition has not well been documented. Neuroglobin, a recently discovered vertebrate protein, shows a neuroprotective function to modulate hypoxic-ischemic brain injury. This study investigated the cognitive function of patients with varying OSA severities and intended to explore the relationship between levels of neuroglobin in serum and cognitive deficits of OSA. Sixty Chinese adults aged 18-59 years old were enrolled and categorized into four groups based on apnea-hypopnea index (AHI): primary snoring (n = 7), mild (n = 13), moderate (n = 20), and severe (n = 20) OSA groups. Computer-based neurocognitive tests (including calculation, memory, and attention) and Epworth sleepiness scale were administered before polysomnographic monitoring, and blood sample was taken the next morning. Concentrations of serum neuroglobin were measured using ELISA. No significant difference was observed in cognitive function regardless of OSA severities, but patients with moderate and severe OSA presented significantly more sleepiness than patients with primary snoring and mild OSA. Memory significantly correlated with time spent with oxygen saturation below 90 % during nighttime (T < 90 %), as well as oxygen desaturation index, AHI, or NREM sleep. Calculation correlated significantly with sleepiness and respiratory arousal index. Levels of neuroglobin in serum of patients with varying OSA severities were significant elevated than that of patients with primary snoring. No relationship was found between the neurobehavioral ability index of neurocognitive tests and serum neuroglobin concentrations after controlling for gender, age, and BMI, whereas the unique association between levels of neuroglobin in serum and the scores of auditory digit span test was noted. Our findings suggest that different neurocognitive domains might specifically correlate to either sleepiness or hypoxemia. Changes of concentrations of neuroglobin in serum may possibly be used as an indicator to monitor the brain damage of OSA. Further investigations are needed to explore the relationship between regulation of neuroglobin in serum and severity of brain damage in OSA.

Use of SPECT to detect changes in diastolic and coronary reserve in patients with obstructive sleep apnea

To assess diastolic function and coronary artery reserve in patients with obstructive sleep apnea (OSA) using single-photon emission computer tomography (SPECT). Patients with OSA who had normal echocardiograph/electrocardiogram findings were divided into three groups based on OSA severity: mild (n = 15), moderate (n = 13), or severe (n = 18). A control group of participants without OSA (n = 17) was included. SPECT (with technetium-99 m-labeled red blood cells) was performed after the induction of cardiac stress by injection of dobutamine. The following ventricular parameters were determined: left ventricular ejection fraction, peak filling rate (PFR), peak ejection rate, 1/3 filling fraction (1/3FF), and regional ejection fractions (rEF). The median ages of OSA and control participants were 45.0 and 51.0 years, respectively. Median apnea-hypopnea index scores were 3.3, 9.1, 38.5, and 65.2 for the control, mild OSA, moderate OSA, and severe OSA groups, respectively. Post-stress, 1/3FF was significantly lower in the overall OSA group compared with the control group (P < 0.05). PFR was significantly lower in the overall OSA group compared with the control group (P < 0.05) and was significantly lower in the severe OSA group compared with the mild OSA group. Regional ejection fractions rEF3 (cardiac apex and a small part of the inferior wall) and rEF4 (anteroseptal wall) were significantly lower in the overall OSA group compared with the control group, suggesting decreased coronary artery reserve. Our findings suggest that SPECT can be used to detect abnormalities in diastolic function and coronary reserve in patients with OSA who have normal electrocardiogram or echocardiograph findings. SPECT may be useful for the early detection of cardiovascular disease in patients with OSA.

Elevated serum cystatin C in severe OSA younger men without complications

Serum cystatin C is a promising new biomarker of glomerular filtration rate and cardiovascular events, but few studies focused on serum cystatin C levels in obstructive sleep apnea (OSA) patients. The aim of our study was to evaluate the association between serum cystatin C and OSA in younger men (≤40 years old of age) without complications. We prospectively recruited consecutive participants without comorbidities who underwent polysomnography. Fasting blood samples were obtained from all subjects for biological profile measurements. Statistical analysis was used to evaluate the relationship between serum cystatin C and other parameters. The population consisted of 98 subjects (mean age = 32.5 years, mean body mass index = 27.93 kg/m(2)) that were divided according to polysomnographic finding into control group (n = 23), mild (n = 15), moderate (n = 24), and severe (n = 36) OSA group. Compared with the control group, patients with severe OSA were significantly heavier (body mass index, 29.69 ± 3.81 vs. 26.42 ± 3.10) and presented significantly higher levels of high sensitive C-reactive protein (hsCRP) (1.10 ± 0.28 vs. 0.88 ± 0.20 mg/l) and serum cystatin C (0.87 ± 0.12 vs. 0.74 ± 0.10 mg/l) (p < 0.05 for all comparisons). Cystatin C was correlated with Apnea Hypopnea Index (AHI), Oxygen Desaturation Index, hsCRP, creatinine, and estimated glomerular filtration rate (r = 0.319, 0.279, 0.321, 0.233, -0.241, p = 0.001, 0.005, 0.001, 0.021, 0.017, respectively). After adjustment for confounding factors, AHI was significantly and positively associated with serum cystatin C levels (β = 0.284, p = 0.007). Our finding indicated that serum cystatin C was associated with the severity of OSA in younger men. Further study is needed to find out whether OSA patients with increased serum cystatin C levels are prone to subclinical cardiovascular and renal diseases.

Severe obstructive sleep apnea increases mortality in patients with ischemic heart disease and myocardial injury

We hypothesized that obstructive sleep apnea(OSA) has a dose-dependent impact on mortality in those with ischemic heart disease or previous myocardial injury. We performed a retrospective cohort study of 281 consecutive OSA patients with a history of myocardial injury as determined by elevated troponin levels or with known existing ischemic heart disease. We compared survival between those with severe OSA [apnea–hypopneaindex (AHI) ≥30] and those with mild to moderate OSA(AHI >5 and <30). Of the 281 patients (mean age 65 years, mean BMI34, 98% male, 58% with diabetes), 151 patients had mild moderate OSA and 130 had severe OSA. During a mean follow-up of 4.1 years, there were significantly greater deaths in the severe OSA group compared to the mild moderate OSA group [53 deaths (41%) vs. 44 deaths(29%), respectively, p00.04]. The adjusted hazard ratio for mortality with severe OSA was 1.72 (95% confidence interval1.01–2.91, p00.04). The severity of obstructive sleep apnea is associated with increased risk of death, and risk stratification based on OSA severity is relevant even in the diseased cardiac patient.

Assessment of left atrial dysfunction in obstructive sleep apnea patients with the two dimensional speckle-tracking echocardiography

The aim of this study was to compare left atrial (LA) longutidinal myocardial function in obstructive sleep apnea (OSA) patients with healthy individuals using two-dimensional speckle-tracking echocardiography method (2D-STE). Twenty one healthy individuals and 58 OSA patients were included. According to the AHI (apnea hypopnea index) patients were examined in mild, moderate and severe OSA groups. Images of the LA were acquired from the apical two- and four-chamber views. LA strain(LA(S)) and strain rate(LA(SR)) parameters [systolic (S), early diastolic (E), late diastolic (A) during atrial contraction] were assessed. LA(S-S), LA(SR-S), LA(S-E) and LA(SR-E) values decreased with severity of OSA. Severe OSA patients have lower LA(S-S) and LA(SR-S) values (p < 0.03). While a difference in the LA(SR-E) value between groups was significant beginning with the moderate OSA group (p < 0.03), no LA(S-E) value differences were observed between moderate and mild OSA groups (p > 0.03). LA(S-A) and LA(SR-A) values were increasing with the disease severity up to moderate OSA. LA(S-A) and LA(SR-A) values of moderate OSA were greater than the mild OSA patients and healthy individuals (p < 0.03). These were lower in severe OSA than the moderate OSA (p < 0.03), however, they were greater than the healthy individuals (p < 0.03). The AHI was found to be negatively correlated with the LA(S-S), LA(SR-S) LA(S-E), LA(SR-E), whereas AHI was not correlated with the LA(S-A), LA(SR-A) values. LA remodeling and dysfunction that accompany OSA can be detected in the subclinical stage with a detailed evaluation of active and passive functions of the LA using the 2D-STE method.

Plasma Pentraxin3 and Arterial Stiffness in Men With Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) induces inflammation and vascular damage that might contribute to an increased risk of cardiovascular disease (CVD). However, the mechanisms linking OSA and CVD are not fully understood. Pentraxin3 may play a significant role in vascular inflammation and damage. Currently, there is lack of data on pentraxin3 and its role in vascular damage associated with OSA. We enrolled 50 males with OSA and 25 controls matched for age and body mass index (BMI). Patients with OSA were further divided into mild and moderate to severe groups. We measured plasma pentraxin3 and evaluated vascular damage using an arterial stiffness parameter--the cardio-ankle vascular index (CAVI)--in all subjects. In the moderate to severe OSA group, pentraxin3 and CAVI were repeatedly measured following continuous positive airway pressure (CPAP) therapy for 1 month. Pentraxin3 levels in the moderate-to-severe OSA group were significantly higher than those in the mild OSA and control groups, with median levels (25th-75th percentile) of 2.36 (1.79-2.78), 1.63 (1.15-2.05), and 1.53 (1.14-2.04) ng/ml, respectively (P < 0.01). Pentraxin3 level was independently correlated with CAVI (coefficient, 0.34 P < 0.01). In the moderate-to-severe OSA group, pentraxin3 and CAVI levels were significantly reduced (P < 0.01 and P = 0.04, respectively) after 1 month of CPAP therapy. Plasma pentraxin3 and arterial stiffness levels in the moderate-to-severe OSA group were greater than the corresponding levels in patients without OSA. However, pentraxin3 level can be managed by CPAP therapy for OSA.

Obstructive sleep apnea causes oxidative damage to plasma lipids and proteins and decreases adiponectin levels

PUPOSE: Obstructive sleep apnea (OSA) is associated with various metabolic disorders, and oxidative stress was suggested to play an important role. In the present study, we aimed to investigate serum adiponectin and oxidative stress markers, especially protein carbonyls, and to evaluate the correlation between these parameters and lipid, insulin and fasting glucose concentrations in OSA patients and controls. Blood was drawn from healthy male volunteers following full-night polysomnographic evaluation. Subjects were classified as controls (n = 24), mild OSA group (n = 9) and moderate-severe OSA group (n = 17) according to their apnea-hypopnea indices (AHIs). Serum lipids, fasting glucose, adiponectin, malondialdehyde (MDA), protein carbonyl concentrations, and paraoxonase activities were measured in all subjects. Results of this study indicated that serum adiponectin concentrations were significantly decreased and MDA and protein carbonyl concentrations were significantly elevated in OSA patients compared to the controls. Protein carbonyl and MDA concentrations were significantly and positively correlated with AHI, while a significant negative correlation was found between adiponectin concentrations and AHI. Adiponectin levels were negatively correlated with MDA levels. Results of this study, which is the first human study investigating and describing serum protein carbonyl concentrations in OSA patients, reveal that OSA causes increments in oxidative damage and decreases adiponectin levels. The recurrent hypoxia-reoxygenation attacks in OSA patients may activate oxidative stress, elevating sympathetic activity and leading to low levels of adiponectin.

Efficacy of continuous positive airway pressure on arrhythmias in obstructive sleep apnea patients

The purpose of this study was to determine the relationship between obstructive sleep apnea (OSA) and cardiovascular disorders in a large Japanese population, and to assess the efficacy of continuous positive airway pressure (CPAP) in the treatment of OSA-associated arrhythmias. The study population comprised 1394 Japanese subjects (1086 men and 308 women) who were divided into four groups on the basis of polysomnography (PSG) analysis as follows: the no sleep apnea (N-SA) group (n = 44, apnea-hypopnea index [AHI] < 5), the mild OSA (Mi-OSA) group (n = 197, 5 < AHI < 15), the moderate OSA (Mo) group (n = 368, 15 < AHI < 30), and severe OSA (SOSA) group (n = 785, AHI < 30). The following baseline characteristics were significantly associated with OSA: age (P < 0.001), gender (P < 0.001), body mass index (P < 0.001), hypertension (P < 0.001), diabetes (P = 0.009), and hyperlipidemia (P = 0.013). In the OSA group, PSG revealed the predominance of paroxysmal atrial fibrillation (PAF) (P = 0.051), premature atrial complex short run (P < 0.005), premature ventricular complex (PVC, P = 0.004), sinus bradycardia (P = 0.036), and sinus pause (arrest >2 s, P < 0.001) during the PSG recording. A total of 316 patients from the group underwent CPAP titration and were then re-evaluated. Continuous positive airway pressure therapy significantly reduced the occurrences of PAF (P < 0.001), PVC (P = 0.016), sinus bradycardia (P = 0.001), and sinus pause (P = 0.004). The results of this study demonstrate a significant relationship between OSA and several cardiac disorders, and also demonstrate the efficacy of CPAP in preventing OSA-associated arrhythmias in a large population of Japanese patients.

Clinical and Polysomnographic Characteristics in Rapid Eye Movement-Related Obstructive Sleep Apnea

Background and Objectives：To evaluate the clinical and polysomnographic features of rapid eye movement (REM)-related obstructive sleep apnea (OSA). Subjects and Method：185 consecutive OSA patients were classified as having REM and nonREM OSA. Subjective symptoms, anthropometric and polysomnographic characteristics between REM OSAS and non-REM OSAS patients were compared. Results：Thirty-eight of the 185 patients (20.5%) were classified as REM OSA, and 147 patients (79.5%) were classified as non-REM OSA. Ninety five percent of the REM OSA patients belonged to the mild or moderate OSA group. The dominant occurrence of apnea and hypopnea in REM sleep did notseem to affect subjective symptoms and daytime sleepiness. Anthropometric and polysomnographic features did not help to differentiate REM OSA from non-REM OSA. Conclusion：REM OSA may not be a separate and specific disease entity of OSA. (Korean J Otorhinolaryngol-Head Neck Surg 2009;52:36-40)

Correlation Between Severity of Obstructive Sleep Apnea and Prevalence of Silent Cerebrovascular Lesions

We investigated the prevalence of silent cerebrovascular lesions in patients with obstructive sleep apnea (OSA) and the correlation between OSA severity and prevalence of silent cerebrovascular lesions in Japanese patients. Study subjects were 192 polysomnography (PSG)-confirmed patients who visited the sleep disorders clinic in our university hospital. None had a history of cerebrovascular disease (CVD). We performed a cross-sectional study on OSA severity and the prevalence of silent cerebrovascular lesions detected by brain MRI analysis. The control (AHI < 5/h) group included 19 subjects with a mean AHI of 1.7 +/- 1.6/h, the mild OSAS (AHI 5 to < 15/h) group included 25 patients with a mean AHI of 9.5 +/- 3.7/h, the moderate OSAS (AHI 15 to < 30/h) group included 35 patients with a mean AHI of 22.0 +/- 7.0/h while the severe OSAS (AHI > or = 30/h) group included 113 patients with a mean AHI of 59.9 +/- 20.5/h. A larger percentage of patients with severe OSAS had a higher BMI and hyperglycemia than those with mild or moderate OSAS and control subjects (p < 0.05). Silent lacunar infarction was identified in 4 (21.1%) control subjects, 3 (12.0%) patients with mild OSA, 17 (48.6%) with moderate OSA and 61 (54.0%) with severe OSA. Among control subjects and the mild, moderate, and severe OSA groups, 4 (21.1%), 5 (20.0%), 19 (54.3%) and 61(54.0%), respectively, had periventricular hyperintensity (PVH); most PVH was mild to moderate. Results indicate that patients with moderate to severe (AHI > or = 15/h) OSA have a higher prevalence of silent cerebrovascular lesion than those with less severe OSA.

Sleep and breathing on the first night after adenotonsillectomy for obstructive sleep apnea

Adenotonsillectomy (T&A) has established effectiveness for the treatment of obstructive sleep apnea (OSA). However, more than 20% of children with OSA have respiratory compromise requiring medical intervention in the postoperative period. The reasons for this complication are not well-defined. We aimed to compare the nature and severity of sleep-disordered breathing in children with mild and severe OSA on the first night following adenotonsillectomy. Ten children were classified into groups of mild and severe OSA, based on preoperative testing. On the first night after T&A, they underwent polysomnography, including electroencephalograph, submental electromyography, bilateral electro-oculograms, monitoring of respiratory movements, heart rate, ECG, and oxygen saturation. Sleep-disordered breathing was assessed by the apnea-hypopnea index, the SaO(2) nadir, and the desaturation index, including dips in saturation below 90% (DI(90)). Sleep quality was assessed by sleep efficiency, time spent in each sleep state, and respiratory arousal index. Obstructive events occurred postoperatively in all children, but were more frequent in those with severe OSA preoperatively: the median (interquartile range) mixed/obstructive apnea/hypopnea indicies were 6.9 (2.2-9.8) events/hr and 21.5 (15.1-112.1) events/hr for the mild OSA group and the severe OSA group, respectively (P = 0.009). Obstructive events were the major cause of desaturation during sleep postoperatively. Sleep quality was severely disrupted in both groups, with reductions in both slow-wave sleep and rapid eye movement sleep. In conclusion, despite removal of obstructing lymphoid tissue, upper airway obstruction occurred on the first postoperative night in children with OSA. This study is the first to demonstrate the mechanism of respiratory compromise after adenotonsillectomy, a common postoperative complication in children with severe OSA.

Angiotensin-converting enzyme gene insertion/deletion (I/D) polymorphism in hypertensive patients with different degrees of obstructive sleep apnea.

To investigate the role of the angiotensin-converting enzyme gene (ACE) insertion (I)/deletion (D) polymorphism in hypertensive patients with different degrees of obstructive sleep apnea (OSA). A case-control study was performed. One hundred seventy four Chinese subjects were divided into four groups depending on the severity of OSA as follows: 1) normal control group (NC, n=68), 2) isolated hypertension group (HT, n=45), 3) hypertensive patients with mild OSA group (MO, n=27), and 4) hypertensive patients with moderate to severe OSA group (MSO, n=34). The distribution of ACE gene I/D allele and genotypes were analyzed in the subject population, as was an OSA pedigree. The study showed that the frequency of ACE gene I/D polymorphism differed significantly among the four groups. The frequency of I allele and II genotype were significantly higher in the MSO group than in the other groups (p<0.05). The distribution of I allele and II genotype showed no significant difference between any of the other groups (p>0.05, respectively). Meanwhile the higher frequency of I allele and II genotype was observed in the OSA pedigree. The higher frequency of ACE gene I allele and II genotype were closely associated with the hypertensive patients with MSO. The inherited factors played an important role in the pathogenesis of hypertensive patients with MSO.