Acute heart failure

Abstract

Obstructive sleep apnea (OSA) is a well-recognized risk factor for cardiovascular diseases, including heart failure (HF), which is a leading cause of morbidity and mortality worldwide. However, the relationship between OSA and HF may be bidirectional. OSA can cause HF via multiple pathways, such as hemodynamic changes, oxidative stress, and inflammation owing to repetitive respiratory effort, desaturation, and reoxygenation accompanied by OSA. In contrast, HF may also develop or worsen OSA owing to fluid retention accompanied by decompensated HF and fluid shift from the lower extremity to the upper airway, resulting in pharyngeal edema and upper airway narrowing. OSA is highly prevalent in patients with acute HF. Concomitant OSA is associated with an increased risk of cardiovascular events in patients with HF, suggesting the need for screening and appropriate treatment for OSA in patients with acute HF to improve their prognosis. Treatments for OSA in patients with acute HF include medical therapy for HF and continuous positive airway pressure (CPAP) therapy for OSA. Diuretics may improve OSA by optimizing fluid management that can alleviate pharyngeal edema, resulting in improvement in OSA. CPAP therapy is the standard therapy for OSA, regardless of the presence or absence of concomitant HF. Evidence suggests that CPAP therapy can improve left ventricular ejection fraction (LVEF) in patients with HF with reduced LVEF. However, strong evidence is scarce on the positive prognostic impact of CPAP therapy in patients with HF and OSA. A recent clinical guideline for HF recommends CPAP therapy for patients with HF with reduced LVEF and moderate to severe OSA (apnea-hypopnea index ≥ 15) to improve left ventricular function, while CPAP therapy is less recommended for improving prognosis.