Published in:
01-12-2018 | Sleep Breathing Physiology and Disorders • Original Article
Nocturnal blood pressure fluctuation and associated influential factors in severe obstructive sleep apnea patients with hypertension
Published in: Sleep and Breathing | Issue 4/2018
Login to get accessAbstract
Purpose
Obstructive sleep apnea syndrome (OSAS) can induce dramatic blood pressure (BP) fluctuations during sleep and it can be associated with hypertension. We investigated the properties and associated influential factors of BP fluctuation in severe OSAS with and without hypertension.
Methods
Two hundred one severe OSAS subjects were divided into hypertensive and normotensive groups. BP was continuously monitored via measurement of pulse transmit time (PTT). The value of apnea-related systolic BP elevation (ΔSBP) was used to reflect the amplitude of BP fluctuation, and the SBP index (the number of ΔSBP > 10 mmHg per hour of sleep time) was used to stand for the frequency of significant BP fluctuations.
Results
Compared with the normotensive group, △SBP and SBP index were higher in the hypertensive group (13.8 ± 4.4 mmHg vs 10.9 ± 3.1 mmHg; 44.8 ± 21.3 events/h vs 26.8 ± 15.8 events/h, all p < 0.001). Multiple regression analysis showed that percentage of sleep time with oxygen saturation < 90% (TST90) and SBP index correlated more with mean level of awakeness and sleep SBP than with apnea-hypopnea index (AHI). Analysis of all apnea events demonstrated that △SBP and the frequency of BP fluctuations were more remarkable following hypoxia than following arousal; △SBP correlated more with oxygen desaturation degree (r = 0.388, p < 0.01) and minimal SpO2 (r = 0.392, p < 0.01) than with apnea length and desaturation duration.
Conclusions
In severe OSAS, nocturnal and awake BP levels are associated more with the nocturnal hypoxic duration and BP fluctuation than with AHI. Nocturnal BP fluctuation can be induced by both hypoxia and arousal, and especially by hypoxia.
Trial registration
NCT02876471