Sleep apnea in stable heart failure: Clinical, polygraphic and echocardiographic characteristics

Sleep apnea syndrome (SAS) is a frequent comorbidity in patients with heart failure (HF), contributing to disease progression and poorer outcomes, yet remains largely underdiagnosed. This study aimed to characterize the clinical, polygraphic, and echocardiographic features of sleep apnea phenotypes in patients with stable HF and to explore differences in cardiac structure and function across phenotypes.

We conducted a cross-sectional study including 80 patients with stable HF. All patients underwent transthoracic echocardiography and overnight respiratory polygraphy. SAS was defined by an apnea-hypopnea index (AHI) ≥5 events/h. Selected descriptive and effect estimates were accompanied by unadjusted 95% confidence intervals (CIs).

SAS was diagnosed in 66 patients (82.5%), including 47 (58.7%) with obstructive sleep apnea (OSA) and 19 (23.7%) with central sleep apnea (CSA). Median AHI was 11.8 [6.5-28.3] events/h, and severe SAS was observed in 18 patients (27.3%). Median BMI differed significantly across the no-SAS, OSA, and CSA groups: 25.4 (22.3-27.6), 29.3 (27.3-31.3), and 28.0 (26.8-30.7) kg/m², respectively (p = 0.015). Overall comparisons were significant for HFrEF (p = 0.008) and HFpEF (p = 0.036), with the highest proportions observed in the CSA and no-SAS groups, respectively. Mean LVEF was 43.5% (35.2-51.8), 45.4% (41.1-49.8), and 32.7% (26.7-38.7) (p = 0.009); median TAPSE was 22.0 (17.0-24.0), 19.0 (16.0-21.0), and 18.5 (17.5-20.0) mm (p = 0.044); and median PASP was 38.0 (36.0-45.0), 35.0 (32.0-41.0), and 56.0 (42.0-72.0) mmHg (p = 0.020). Bonferroni-adjusted Dunn tests showed significant pairwise differences for BMI (OSA vs no-SAS, p = 0.012), LVEF (CSA vs OSA, p = 0.006), and PASP (CSA vs OSA, p = 0.018), but not TAPSE.

SAS was highly prevalent in stable HF, with OSA predominating. In this exploratory, unadjusted study, clinical and echocardiographic characteristics differed across phenotypes, with the lowest LVEF and TAPSE and highest PASP observed in CSA. Significant pairwise differences were found for BMI, LVEF, and PASP.