6A.06

Abstract

Abstract Obstructive sleep apnea (OSA) causes blood pressure (BP) surge while OSA episode occurs. It could lead to increase of not only nocturnal BP level but also nocturnal BP variability, both of which increase the cardiovascular risk. Therefore, the assessment of BP surge could be valuable for the risk stratification and predicting cardiovascular events. We recently developed a trigger sleep BP monitoring (TNP) method that initiates BP measurement when oxygen desaturation falls below a variable threshold, and demonstrated that it can detect BP surge during apnea episodes. In this study, we evaluated the reproducibility of nocturnal BP parameters measured by TNP. 149 outpatients in whom polysomnography (PSG) was planned for the diagnosis of OSA (mean age 59.5 ± 13.7, 86.6% men) were subjected to TNP with PSG in the hospital for 2 consecutive days. In the same way as our previous study (J Clin Hypertens. 2014;16:459-466), we defined the hypoxia-peak SBP as the maximum SBP measured by an oxygen-triggered function, sleep SBP surge as the difference between hypoxia-peak SBP and the average of the SBPs measured by a fixed-interval function (30 min. intervals) within 30 minutes before and after the hypoxia-peak SBP, mean sleep SBP as the average of the sleep BPs measured only by the fixed-interval function, and minimum (basal) sleep SBP as the lowest SBP among all the sleep BPs measured by both oxygen-triggered and fixed-interval functions. Reproducibility was evaluated using the Repeatability Coefficient (RC), and the Intraclass Correlation Coefficient (ICC) for agreement. Mean SBP and mean DBP measured by both fixed-interval function and oxygen-triggered function, and hypoxia-peak SBP measured by oxygen-triggered function corresponded well in each day (ICC ranged 0.69 - 0.88). On the other hand, the reproducibility of sleep SBP surge (ICC 0.33) and minimum (basal) sleep SBP (ICC 0.39) was low. In conclusion, in the TNP parameters, the reproducibility of the hypoxia-peak SBP was good and comparable to mean sleep SBP measured by ordinary fixed interval BP monitoring.(Figure is included in full-text article.).