The sleep analysis included overnight polysomnography, which documented the sleep disturbances and severity of the OSAS according standard

criteria [1]. The investigation was performed with MEPAL (MAP, Medizin – Technologie, Martinsried, Germany) monitoring system. According to the known diagnostic standards, the minimal time for examination was 6 h. For the documentation of the sleep, we used standard 16–18 channel polysomnography, including electroencephalogram (C3–A2, C4–A1, O1–A2, O2–A1), electro-oculograms, electromyograms (EMG) of the left/right extremity, electrocardiogram (ECG), heart rate, nasal and oral air flow, thoracic and abdominal movements, registration of snoring, position of the body, pulseoxymetry-monitored BMN 673 concentration oxygen saturation (SaO2) and a polysomnography with video-watching. The sleep phases and arousals were analyzed in conformity with Rechtschaffen and Kales’ criteria [14]. All the results were analyzed manually. The breathing was registered by nasal cannulas and combined respiratory inductive

plethysmography, which uses composed signal and a thermistor. Apneas and hypopneas were evaluated in accordance with the accepted international criteria [1]. The apnea index (AI) was defined as the number of apneas per hour sleep while hypopnea index (HI) – the number of hypopneas buy SCR7 per 1 h sleep. The apnea/hypopnea index (AHI), combined the number of apnea and hypopnea per 1 h sleep. The index of desaturation was defined as episodes of O2 desaturation >3% per hour sleep compared to a stable basic value. The severity of

the sleep apnea was graded as: mild, with AHI 5–15 episodes of apnea and hypopnea per hour of sleep; moderate, with AHI 16–30 episodes of apnea and hypopnea per hour of sleep and severe, AHI more than 30 episodes of apnea and hypopnea per hour of sleep. The main arteries of the head were examined with color-coded duplex sonography using a 7.5 MHz transducer on Sonix SP (Canada). Real time B-mode imaging was used to measure the thickness of the intima CYTH4 media complex (IMT) of the carotid arteries (mm) with a standard method, using a program for automatic value averaging [2], [5], [17] and [18]. The rate of the stenosis was determined with the morphologic method in longitudinal and transversal slice of the examining vessel. They were categorized as: no observable stenosis (1–24%), low grade stenosis (25–49%), moderate stenosis (50–74%), high grade stenosis (75–99%) and thrombosis (100%) [3]. According to their structure the plaques were determined as homogeneous, heterogeneous, mixed and calcified. Their surfaces were evaluated as smooth (regular), rugged (irregular) or having cavities (more than 2 mm concaves and ulcers). Clinically, the plaques were characterized as stable (homogeneous, smooth and fibrous cover) and non-stable (heterogeneous, with inner hemorrhages and cholesterol spots) [1].