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.
Secondary analysis of ECG and pulse-oximetry-[oxygen saturation (SpO2)] 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 (control group), continuous positive airway pressure (CPAP) or nocturnal supplemental oxygen. Participants with good-quality ECG-signal and SpO2-signal (n = 241) were included.
CPAP-therapy significantly improved BP, with net average improvement in mean arterial blood pressure during sleep (MAPSleep) 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 MAP24 −3.13 (P = 0.030) and MAPSleep −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 (SQIBaseline-SQIFollow-up), controlling for sex, age over 60, apnea–hypopnea index, SpO2 less than 80%, baseline BP and cardiovascular disease, significant differences are observed comparing the groups that Improved-SQI (SQIBaseline < 55, SQIFollow-up ≥ 55) and Declined-SQI (SQIBaseline ≥ 55, SQIFollow-up < 55) in MAP24 −4.87 (P = 0.046) and mean diastolic blood pressure (MDP24) −4.42 (P = 0.026) as well as MAPWake −6.36 (P = 0.015), mean systolic blood pressure wake (MSPWake) −7.80 (P = 0.048) and mean diastolic blood pressure wake (MDPWake) −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.
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.