A9803 The effect of obstructive sleep apnea on blood pressure variability in resistant hypertension

Abstract

Objectives: Obstructive sleep apnea is a common respiratory disorder associated with hypertension and cardiovascular complications. Blood pressure variability may be a sign of risk of cardiovascular events. Methods: The aim of this study was to investigate the hypothesis that OSA syndrome is associated with increased blood pressure variability (BPV) in patient with resistant hypertension. Based on polysomnography, 74 patients were categorized into two groups: AHI ≤ 15 episodes per hour (mean 8.60 ± 4.67) and apnea/hypopnea index (AHI) > 15 episodes per hour (mean 36.53 ± 20.79). A 24-h noninvasive blood pressure monitoring was performed. The standard deviation of mean blood pressure was used as the indicator of BPV. Results: In patients with moderate-to sever OSA, compared with control group, increased diastolic BPV (11.06 ± 2.99 vs. 10.06 ± 2.18, p < 0.05) was detected. There was no statistical differences in mean systolic and mean diastolic blood pressure. There was a positive linear correlation between diastolic BPV and arausal index (r = 0.45, p < 0.05) and also diastolic BPV and N1 duration [%TST] (r = 0.450, p < 0.05). We have observed positive linear corralation between nocturnal diastolic BPV and arousal index (r = 0.35, p < 0.05), and also diastolic BPV and N1 duration (%TST) (r = 0.32,p < 0.05). There was negative linear correlation between nocturnal diastolic BPV and N3 duration (%TST) (r = −0.26, p < 0.05). Conclusion: The findings of the study point to increased diastolic blood pressure variability as risk factor of cardiovascular complications in patients with moderate to severe OSA and resistant hypertension.