Abstract
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 VO(2)), percent-predicted peak VO(2) and oxygen uptake at anaerobic threshold (VO(2)-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 VO(2) in comparison to control (67 ± 17 to 73 ± 19%; p = 0.01). Additional primary endpoints peak VO(2) and VO(2)-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 VO(2), an established surrogate marker for cardiovascular prognosis in HFrEF. APAP has additional beneficial effects on hypoxemia, cardiac function and quality of life.