Autonomic regulation of blood circulation in hypertensive patients with obstructive sleep apnea syndrome

Abstract

Objective. To assess autonomic regulation in hypertensive patients with and without obstructive sleep apnea syndrome and in relation to the severity of sleep-disordered breathing. Design and methods. We included 107 subjects, mean age 53,0 ± 8,4 years, 85 males and 22 females. The main group included 77 hypertensive patients who were divided into 2 groups based on the results of sleep study: 37 patients with obstructive sleep apnea syndrome and 40 subjects without sleep-breathing disorders. Control group included 30 normotensive subjects without sleep apnea. All patients underwent clinical examination, 24-hour blood pressure monitoring (SpaceLabs 90207, USA), cardiorespiratory study (Embletta Pds, MedCare Flaga, Iceland), assessment of autonomic regulation of blood circulation by Finometer (FMS, Amsterdam) and vasomotor reactivity by occlusion plethysmography according to Dohn. Results. Sleep apnea patients and hypertensives without sleep-breathing disorders had lower autonomic barorefl ex than controls (5,6 ± 2,8; 6,7 ± 1,6 and 9,8 ± 2,4 ms/mmHg, p < 0,005 and p < 0,01, respectively). Subjects with more severe sleep apnea demonstrated lower parameters of spontaneous arterial barorefl ex. Valsalva index was reduced in sleep apnea patients (1,45 ± 0,22) compared to hypertensive patients without sleep-breathing disorders (1,71 ± 0,31, p < 0,01) and controls (1,72 ± 0,25, p < 0,01). Forearm cutaneousmuscular blood fl ow velocity was decreased in patients with obstructive sleep apnea syndrome (3,7 ± 1,7 ml/ min×100 cm 2 ) compared to controls (5,8 ± 2,2 ml/min×100 cm 2 , p < 0,05) and subjects without sleep apnea (6,5 ± 2,6 ml/min×100 cm 2 , p < 0,01). Conclusions. Lower control of arterial hypertension in hypertensive