Effect of Obstructive Sleep Apnea Syndrome on Arterial Stiffness in Patients at High Cardiovascular Risk

Aim. To assess the impact of metabolic abnormalities in combination with obstructive sleep apnea on endothelial function and vascular stiffness parameters in patients with arterial hypertension 1-2 degrees. Material and methods. Patients (n=74) with metabolic syndrome and obstructive sleep apnea were included into the study. All patients underwent cardiorespiratory monitoring of sleep using SomnoCheck2 device (Wiennmann, Germany) and were divided into two groups based on its results. Patients with apnea-hypopnea index (AHI) <30 episodes per hour were included into group 1 and patients with AHI >30 episodes per hour – into group 2. Monitoring of ambulatory blood pressure (BP) and arterial stiffness was performed by the device BPLab ("Peter Telegin", Russia). Endothelial function was assessed in a probe of flow-mediated dilation by the ultrasound device MyLab 90 (Esaote, Italy). Diameter of the common carotid artery (DCCA) and the intima-media thickness (IMT) were determined. Results. Patients with AHI >30 episodes per hour had higher mean daily and night systolic BP and pulse BP in aorta and brachial artery. Pulse wave velocity in aorta in per day averaged was also higher in these patients (8.2±0.8 vs 9.1±1.1 m/sec; p<0.05). Mean level of flow-mediated dilation was significantly lower in patients with severe sleep apnea> (8.8% (5.6; 13.1) vs 4.5% (2.2; 8.0); p<0.05). Prevalence of negative index of reactivity in group 2 was 2 times higher than this in group 1. An increase in IMT and DCCA in patients with severe obstructive sleep apnea was also revealed. Conclusion. Severe sleep apnea in patients with metabolic syndrome in combination with hypertension aggravates structural changes and endothelial dysfunction of the main arteries, as well as contributes to the progression of atherosclerosis.