Diagnosis and Treatment of Sleep Apnea in the Acute Exacerbation of Heart Failure

Overview

Congestive heart failure affects 2.3 percent of the population (approximately 4,900,000) with an incidence of 10 per 1,000 of the population after the age of 65 (1). The admission rate for patients with heart failure is on the rise, so is the mortality associated with it and its national annual bill, now exceeding $21 billion (1). Obstructive Sleep Apnea (OSA) is present in 11-37 percent of patients with heart failure (2,3), and tends to increase in severity when the heart failure is less controlled (4, 5). Therefore, the actual prevalence of OSA in patients hospitalized with acute heart failure is likely higher. There is now evidence that treatment of OSA with nasal Continuous Positive Pressure (nCPAP) in outpatients with stable heart failure improves left ventricular ejection fraction, and quality of life (6), and confers a reduction in fatal and non-fatal cardiovascular events (7). However, there has not been any evaluation of the role of diagnosis and treatment of OSA in patients hospitalized with acute heart failure. This uncertainty about the true prevalence and role of OSA in exacerbations of heart failure, and the role of its treatment in the acute setting may explain why aggressive diagnostic and therapeutic strategy for OSA in patients admitted to the hospital with acute heart failure is not part of the standard clinical practice in acute care centers. Given the rising admission rate, and mortality associated with heart failure, an evaluation of the role of OSA and its treatment in this patient population is highly significant.

OSA is associated with large negative swings in the intrathoracic pressure, significant increase in the sympathetic nerve activity and repetitive surges in blood pressure, along with episodic hypoxia and hypercapnea (8, 9). These autonomic and respiratory changes may increase the cardiac muscle workload, cardiac dysrrhythmia, and exacerbate ischemia (10,11,12). Treatment with continuous positive airway pressure (CPAP) is the most successful therapeutic modality available for obstructive sleep apnea. It is still not clear whether establishing the diagnosis of OSA and initiating treatment with CPAP while still in the hospital carries any benefit in the management of patients with acute heart failure. This study will evaluate the effect of work up and treatment of OSA on the outcome of patients hospitalized with acute congestive heart failure (CHF).