Hypoxaemic burden in heart failure patients receiving adaptive servo-ventilation

Aims: This study aimed to assess the effectiveness of adaptive servo-ventilation (ASV) for lowering hypoxaemic burden components in heart failure with reduced ejection fraction (HFrEF) patients. Methods and results: Fifty-six stable HFrEF patients with left ventricular ejection fraction = 40 were randomized to receive either ASV (n = 27; 25 males) or optimal medical management or optimal medical management alone (n = 29; 26 males). Patients underwent overnight polysomnography at baseline and a 12 week follow-up visit. We quantified hypoxaemic as time spent at <90% oxygen saturation (T90) decomposed into desaturation-related components (T90desaturation) and non-specific drifts (T90non-specific). In the ASV arm, T90 significantly shortened by nearly 60% from 50.1 ± 95.8 min at baseline to 20.5 ± 33.0 min at follow-up compared with 59.6 ± 88 and 65.4 ± 89.6 min in the control arm (P = 0.009). ASV reduced the apnoea-related component (T90desaturation) from 37.7 ± 54.5 to 2.1 ± 7.3 min vs. 37.7 ± 54.5 and 40.4 ± 66.4 min in the control arm (P = 0.008). A significant non-specific T90 component of 19.6 ± 31.8 min persisted during ASV. In adjusted multivariable regression, T90desaturation was significantly associated with the ratio of the forced expiratory volume in the first second to the forced vital capacity of the lungs (ß = 0.336, 95% confidence interval 0.080 to 0.593; P = 0.011) and T90non-specific with left ventricular ejection fraction (ß = -0.345, 95% confidence interval -0.616 to -0.073; P = 0.014). Conclusions: ASV effectively suppresses the sleep apnoea-related component of hypoxaemic burden in HFrEF patients. A significant hypoxaemic burden not directly attributable to sleep apnoea but related to the severity of heart failure remains and may adversely affect cardiovascular long-term outcomes.