Background: Moderate-to-severe obstructive sleep apnea (OSA) is highly prevalent in heart failure patients with reduced left ventricular ejection fraction (HFrEF), and is associated with worsening cardiac function and increased mortality.
Objectives: The automatic positive airway pressure (APAP) trial tested the impact of APAP treatment on changes for the pre-specified endpoints: changes in peak oxygen uptake (peak VO2), percent-predicted peak VO2 and oxygen uptake at anaerobic threshold (VO2-AT).
Methods: This randomized, controlled pilot study included patients with chronic, stable HFrEF who had moderate-to-severe OSA. Patients were randomized 1:1 to either APAP (AutoSet™, ResMed) or nasal strips (control) for 6 months.
Results: 76 patients have been randomized and 58 had complete data for final analysis. There was a statistically significant change in the APAP intervention arm for the primary endpoint percent-predicted peak VO2 in comparison to control (67 ± 17 to 73 ± 19%; p = 0.01). Additional primary endpoints peak VO2 and VO2-AT showed a trend in increase in the APAP group. Moreover, there were significant improvements within the APAP group for hypoxemia, left ventricular function and quality of life from baseline to 6 months, but not within the control group (p = 0.001 and p = 0.037, respectively).
Conclusion: APAP intervention was shown to significantly improve outcome compared to control group, represented in percent-predicted peak VO2, an established surrogate marker for cardiovascular prognosis in HFrEF. APAP has additional beneficial effects on hypoxemia, cardiac function and quality of life.
Keywords: Heart failure with reduced ejection fraction; Obstructive sleep apnea; Positive airway pressure; Sleep-disordered breathing.