Sleep disordered breathing is not associated with excessive daytime sleepiness in congestive heart failure patients

Abstract

Background: Sleep Disordered Breathing (SDB) has important clinical implications in patients with stable Congestive Heart Failure (CHF). While OSA represents an independent risk factor for cardiovascular disease and might contribute to CHF progression, CSA seems to be a manifestation of advanced heart failure. We aimed to analyse if the Epworth Sleepiness Scale Score (ESS), a simple questionnaire to detect daytime sleepiness, is able to predict SDB in this patient population. Methods: We studied 176 consecutive subjects on Optimal Medical Therapy (OMT) who are under supervision of the heart failure clinic in our hospital. Patients had a median left ventricular ejection fraction (LVEF) of 25.0% (range: 7 - 35%) and median NT-pro BNP levels of 3413.0 pg/ml (range: 305.1 to 35000.0 pg/ml). The Epworth Sleepiness Scale (ESS) was used to assess the degree of daytime sleepiness. A patient with a score of greater than 11 was considered as being excessively sleepy. For detecting SDB, subjects underwent prospectively unattended overnight recording using a six channel recording device (Embletta X10®) irrespective of symptoms associated with SDB. Results: 50% presented with an at least a moderate form of nocturnal breathing disorder (apnea hypopnea index (AHI) ≥ 15/hr). Only 15 patients (17.1%) with AHI ≥ 15/hr reported excessive daytime sleepiness (ESS > 11). By analysing the main type of SDB, the median and the ranges of the ESS scores for an AHI < 15/hr, OSA, and CSA were 6.5 (0-24), 8.0 (0-19), 6 (0-17) showing no statistic significant difference between patients with an AHI < 15/hr and obstructive sleep apnea, an AHI < 15/hr and central sleep apnea, as well as within obstructive and central sleep apnea (p=0.249; p=0.523; p=0.249, respectively). Conclusions: Stable CHF patients with at least moderate SDB do not suffer from excessive daytime sleepiness. Therefore, SDB cannot be easily ruled out by the ESS questionnaire in this population.