Prevalence of Sleep Disordered Breathing in Congestive Heart Failure as Determined by ApneaLink, a Simplified Screening Device

Background: Sleep disordered breathing (SDB) is very common in patients with congestive heart failure (CHF), with some studies reporting an incidence of 50%. Increased sympathetic activity, caused by frequent arousals (increased ApneaHypopnea Index [AHI]) during the night has been implicated as a contributing factor in a four-fold increase in mortality for CHF patients. Many patients are undiagnosed for SDB due to lack of awareness of the disorder and access to an easy, reliable screening test. The purpose of this study is to evaluate the prevalence of SDB in patients with CHF in the inpatient and outpatient settings using the ApneaLink (AL) (ResMed Corp, San Diego, CA) screening device. Methods: 86 patients with CHF from the VA San Diego Healthcare System were enrolled. Eligible patients are those with diagnosis of CHF, treatment naïve for SDB, and symptomatic for sleep apnea (SA) per an SDB questionnaire created by study personnel. The mean age was 66 years, and the mean BMI was 32 kg/m2. SDB was defined using an AHI result of "5 events/hour. The prevalence of SA was determined from the Apnea-Hypopnea Index (AHI) data recorded by the AL. Patients were included in the analysis if they had a minimum of 4 hours evaluation time (ET). Determination for the presence of Cheyne-Stokes respiration (CSR) was performed by evaluation of the flow signal data. Results: Seventy percent (61/86) of the patients met the enrollment criteria. The overall prevalence of SA was 85% (52/61 subjects). CSR was detected in 33% (20/61 subjects). For the 46 subjects who completed the study in the outpatient setting, the prevalence of SAand CSR are 83% and 26%, respectively. In the inpatient setting, 15 patients with an admission diagnosis of CHF completed the study with a prevalence of 93% and 53% for SA and CSR, respectively. Conclusions: SDB appears to be relatively common in the CHF population, regardless of age. Preliminary results provide supportive evidence for the clinical need to identify, diagnose and treat the CHF patient with SDB. The AL is a relatively simple test to administer to patients and easy to use by patients in the home setting. A larger sample size of hospital patients using the device is required to evaluate utility in the