The influence of renal insufficiency on sleep-disordered breathing in patients with symptomatic chronic heart failure.
BACKGROUND
Renal insufficiency, a common condition among patients with chronic heart failure, complicates the management of heart failure. However, the influence of renal insufficiency on sleep-disordered breathing (SDB) - another important comorbidity of heart failure - has not been well studied.


METHODS
Seventy-nine patients (60 men and 19 women) with stable, symptomatic heart failure caused by left ventricular systolic dysfunction (left ventricular ejection fraction of less than 45%) were studied.


RESULTS
Thirty-nine patients (49%) had SDB as defined by an apnea-hypopnea index (AHI) of five or greater: 15 patients were classified as having mild SDB (AHI of five or greater and less than 15), 10 patients as having moderate SDB (AHI of 15 or greater and less than 30) and 14 patients as having severe SDB (AHI of 30 or greater). The etiology of SDB was predominantly central. Plasma brain natriuretic peptide concentration in the severe SDB group was 587±377 pg/mL, which was significantly higher than those of the remaining three groups (P<0.05). On the other hand, estimated glomerular filtration rate (eGFR) was comparable between non-SDB and SDB groups. There was no statistically significant correlation between eGFR and AHI, or between eGFR and the number of central sleep apneas in the study patients.


CONCLUSIONS
Higher plasma brain natriuretic peptide concentrations were associated with more severe SDB, whereas the level of eGFR was not correlated with the severity of SDB. The results suggest that renal dysfunction plays a relatively minor role in determining breathing abnormalities in chronic heart failure.
Department of Cardiology, Kyushu Kosei-Nenkin Hospital, Kitakyushu, Japan.
Umpei
U
Yamamoto
Masahiro
M
Mohri