Cardiopulmonary coupling-derived sleep quality is associated with improvements in blood pressure in patients with obstructive sleep apnea at high-cardiovascular risk

Objective: Investigate if changes in objective sleep quality index (SQI) assessed through cardiopulmonary-coupling analysis impacts blood pressure (BP) in patients with obstructive sleep apnea at high-cardiovascular risk. Methods: Secondary analysis of ECG and pulse-oximetry-[oxygen saturation (SpO 2 )] data from the Heart Biomarker Evaluation in Apnea Treatment study, multicenter, controlled trial in patients with cardiovascular disease and moderate-severe obstructive sleep apnea, randomly assigned to intervention of healthy lifestyle and sleep hygiene education (HLSE; control group), continuous positive airway pressure (CPAP) or nocturnal supplemental oxygen (NSO). Participants with good-quality ECG-signal and SpO 2 -signal ( n = 241) were included. Results: CPAP-therapy significantly improved BP, with net average improvement in mean arterial blood pressure during sleep (MAP Sleep ) when compared with nocturnal supplemental oxygen-therapy or healthy lifestyle and sleep education-therapy, −3.92 ( P = 0.012) and −3.83 ( P = 0.016), respectively. When stratified on the basis of baseline-SQI, CPAP-therapy improves 24-h MAP 24 −3.02 ( P = 0.030) and MAP Sleep −5.00 ( P = 0.001), in patients with compromised baseline-SQI (SQI < 55). Stratifying the cohort based on changes in SQI during the study period (SQI Baseline -SQI Follow-up ), controlling for sex, age over 60, apnea–hypopnea index, SpO 2 less than 80%, baseline BP and cardiovascular disease, significant differences are observed comparing the groups that Improved-SQI (SQI Baseline < 55, SQI Follow-up ≥ 55) and Declined-SQI (SQI Baseline ≥ 55, SQI Follow-up < 55) in MAP 24 −4.87 ( P = 0.046) and mean diastolic blood pressure (MDP 24 ) −4.42 ( P = 0.026) as well as MAP Wake −6.36 ( P = 0.015), mean systolic blood pressure wake (MSP Wake ) −7.80 ( P = 0.048) and MDP Wake −5.64 ( P = 0.009), respectively. Improved SQI reflects the magnitude of positive effect on BP which is reached mostly through initiation of CPAP-therapy. Conclusion: Cardiopulmonary coupling-derived sleep quality impacted 24-h MAP and MDP, as well as BP during wake, in patients participating in the Heart Biomarker Evaluation in Apnea Treatment-study.