Nighttime blood pressure in patients with obstructive sleep apnea syndrome (OSAS)

Introduction: Obstructive sleep apnea syndrome (OSAS) is often associated with increased prevalence of hypertension. It is well known that elevated nocturnal blood pressure increase prevalence of cardiovascular complications. Therefore the aim of our study was to investigate the nocturnal systolic, diastolic and mean blood pressure (RRs, RRr and MAP) and also puls pressure (PP) and heart rate (HR) depending on severity of OSAS. Material and methods: In the course of OSAS (obstructive sleep apnea syndrome) diagnostic workup systolic, diastolic and mean blood pressure (RRs, RRr and MAP), pulse pressure (PP) and heart rate (HR) were assessed during polysomnografy (PSG) in 20 patients, aged 33-66. Patients were randomized in three groups: patients with AHI (apnea-hypopnea index) < 5, as a reference group 1, patients with AHI within 5 and 30 (group 2), and patients with AHI >30 (group 3). Results: RRs in group 3 (133 mmHg) was higher than in group 1(118.5 mmHg, p<0.01) and group 2 (114.5 mmHg; p<0.05). In group 3, RRr (81 mm Hg) was higher if compared with group 2 (74.0 mm Hg; p<0.02) and it was comparable to that of group 1 (72.5 mm Hg). MAP was higher in group 3 (100.0 mm Hg) than in group 1 (88.0 mm Hg; p<0.02) and group 2 (87.5 mm Hg; p<0.01). PP in group 3 (50.5 mm Hg) was increased compared with both group 1 (47.0 mm Hg; p<0.01) and group 2 (42.0 mm Hg; p<0.01). HR in group 3 (65.0 min-1) was higher than in patient in group 1 (63.0 min-1; p<0,05) but it did not differ from group 2 (66.0 min-1). There was no significant difference between group 2 and 1. Conclusions: The severity of respiratory abnormalities in OSAS significantly affects RRs, RRr, MAP, PP and HR. The severe OSAS is associated with significant HA risk. (Clin Exp Med Lett 2007; 48(4): 249-253)

Keywords: obstructive sleep apnea syndrome (OSAS),, blood pressure (BP),, polysomnografy (PSG), apnea-hypopnea index (AHI)