Purpose: Continuous positive airway pressure (CPAP) therapy is a well-established treatment for obstructive sleep apnea (OSA). In this study, we aimed to assess the effects of CPAP therapy on nocturnal blood pressure (NBP) fluctuations (NBPFs) during rapid eye movement (REM) and non-REM sleep, and the NBPF patterns in patients with OSA.
Methods: This retrospective study included 34 patients with moderate-to-severe OSA who underwent polysomnography using pulse transit time pre-CPAP therapy and 3–6 months post-CPAP therapy. We investigated NBP and the frequency of NBPFs in REM and non-REM sleep, as well as changes in NBPFpatterns post-CPAP therapy.
Results: The apnea-hypopnea index (AHI), arousal index, systolic NBP, diastolic NBP, diurnal systolic BP (SBP), diastolic BP (DBP), and frequency of NBPFs in REM and non-REM sleep were significantly reduced post-CPAP therapy (all p < 0.01). A higher pre-CPAP AHI was associated with a reduction in diurnal SBP, systolic NBP, and NBPFs post-CPAP (r = 0.32, p = 0.028; r = 0.40, p = 0.019; and r = 0.51, p = 0.002; respectively). However, 58.8% of the patients showed no NBPF pattern change with CPAP therapy.
Conclusion: In REM and non-REM sleep, almost all sleep-related parameters, NBP, and frequency of NBPFs significantly improved post-CPAP therapy, whereas NBPF patterns showed varying changes 3–6 months post-CPAP therapy. These results suggest that factors other than OSA influence NBPF pattern changes.