[Prevalence of sleep-related breathing disorders in ischemic and non-ischemic heart failure]

Abstract

Background and objective: The prevalence of sleep-disordered breathing (SDB) in patients with chronic heart failure seems to be remarkably high, but existing studies are based on small cohorts of patients who were not receiving guideline-based drug treatment for heart failure. The aim of this study was to investigate the prevalence of SDB in patients with ischemic (ICM) or non-ischemic (DCM) cardiomyopathy.

Patients and methods: A total of 647 consecutive patients (130 females, 517 males; mean age 63.23 10.4 years) in stable, symptomatic chronic heart failure (NYHA class at least II) and with impaired systolic left ventricular function (ejection fraction < or = 40%) were screened by cardiorespiratory polygraphy for the presence and type of SDB. Sleep apnea was classified as obstructive (OSA) or central (CSA) according to the majority of events, and as ICM or DCM according to the results of current left heart catheterization. SDB was defined according to the apnea-hypopnea index (AHI) as: no SDB: < or = 5/h, mild: 6 -14/h, moderate: 15-29/h, and severe > or = 30/h.

Results: Prevalence of SDB was 70% among DCM and 82% among ICM patients (p < 0.05). Central sleep apnea was found in 32% of DCM and 46% of ICM patients, obstructive sleep apnea in 38% of DCM and 36% of ICM patients. Moderate (15.7% vs. 9.9%, p < 0.05) and severe central sleep apnea (24.4% vs. 15.5%, p < 0.05) was documented more often in ICM than DCM patients. Severity of obstructive sleep apnea was similar in ICM and DCM patients. ICM patients were older than DCM patients (66.4 11 years vs. 66.0 9.0 years, p < 0.01) and in general presented with a greater impairment of cardiopulmonary function.

Conclusions: There is a high prevalence of SDB in patients in chronic heart failure. Central sleep apnea can be documented particularly in ICM patients and seems to be a marker for the severity of heart failure. Because of their prognostic implications, risk stratification and identification of patients eligible for specific SDB treatment, screening for such disorders should be part of every heart failure work-up.