Differential impact of body position on the severity of disordered breathing in heart failure patients with obstructive vs. central sleep apnoea

Aims Obstructive (OSA) and central sleep apnoea (CSA) are a common comorbidity in patients with heart failure. The purpose of this study was to assess and compare the impact of body position on the severity of sleep apnoea in these two groups of patients. Methods and results Standard polysomnography was performed in consecutive, clinically stable, optimally treated patients with moderate-to-severe heart failure and systolic dysfunction. Patients with an apnoea-hypopnoea index (AHI) ≥15/h (n = 120) were included in the study. The severity of sleep-disordered breathing was quantified by the AHI, the mean value of oxygen desaturations (O₂desat) and the apnoea ratio. Data from the right and left positions were combined into a single lateral position. Positional sleep apnoea was defined as a >50% reduction in the AHI between the supine and the lateral position. Twenty-nine and 91 subjects had dominant OSA and CSA, respectively. The AHI markedly decreased from the supine to the lateral position in both groups [OSA: (median [q1,q3]) 50.3 [36.9, 67.6]/h vs. 10.4 [7.0, 18.5]/h, P <0.0001; CSA: 47.4 [37.6, 56.0]/h vs. 19.3 [11.9, 33.3]/h]. The reduction was greater in OSA patients (p = 0.027). Similarly, O₂desat and the apnoea ratio decreased in the lateral position (P <0.0001). Positional sleep apnoea was observed in 76% of OSA and 53% of CSA patients (P = 0.028). Conclusion This study demonstrates that the lateral sleeping position has a major beneficial effect on the severity of sleep-disordered breathing in heart failure patients, and that this improvement is greater in subjects with OSA than in those with CSA.