Continuous positive airway pressure improves exercise capacity and heart rate recovery in obstructive sleep apnea

Abstract

BackgroundThere is a relationship between obstructive sleep apnea (OSA) and heart failure (HF). Peak oxygen consumption (peak VO2), heart rate recovery, and N-terminal-pro-BNP (NT-proBNP) are strong prognostic predictors in HF. The effects of nasal continuous positive airway pressure (nCPAP) on these parameters in OSA patients are not well defined. MethodsForty patients with newly diagnosed OSA [apnea–hypopnea index (AHI) 37 (20–65) h−1] underwent cardiopulmonary exercise testing for assessment of peak VO2 and heart rate recovery at one (HRR-1) and two (HRR-2) minutes after exercise termination as well as NT-proBNP measurement at baseline and after 7.9±1.4 months of effective nCPAP (nightly usage>3.5 h). The effects of nCPAP were compared in patients with mild-to-moderate (AHI<30 h−1; n=16) vs. severe (AHI≥30 h−1; n=24) OSA. ResultsIn the group as a whole, peak VO2 (baseline: 31.9±9.3 vs. follow-up: 33.7±9.0 ml/kg/min; p=0.02) and HRR-2 [38 (32–43) vs. 42 (32–47) bpm; p=0.01] but not HRR-1 [22 (15–26) vs. 22 (16–27) bpm; p=0.16] improved from baseline to follow-up. The effect on peak VO2 was mainly driven by a trend towards an increase in patients with mild-to-moderate OSA (31.8±10.7 vs. 33.9±10.2 ml/kg/min; p=0.08), whereas an effect on HRR-1 [20 (15–23) vs. 21 (16–26) bpm; p=0.03] and HRR-2 [38 (29–42) vs. 42 (33–47) bpm; p=0.004] was observed only in those with severe OSA. NT-proBNP levels remained unchanged [21 (11–45) vs. 26 (5–52) pg/ml; p=0.6]. ConclusionsTreatment with nCPAP is associated with an improvement in peak VO2 and heart rate recovery in patients with OSA.