title: C-reactive protein is elevated in heart failure patients with central sleep apnea and Cheyne-Stokes respiration.
abstract: BACKGROUND
  Manifestation of central sleep apnea (CSA) with Cheyne-Stokes respiration is of major prognostic impact in chronic heart failure (CHF). Inflammatory processes have been linked to a progression of cardiovascular diseases, including heart failure. While an association of C-reactive protein (CRP) levels to obstructive sleep apnea has been documented before, there is a lack of information regarding variation of CRP levels in patients with CSA.
  
  
  OBJECTIVE
  The objective of this study was to investigate a potential association of CRP levels to CSA severity in CHF patients.
  
  
  METHODS
  High sensitivity CRP levels were analyzed in 966 patients with CHF (BMI 26.3 ± 4.6, New York Heart Association class 2.6 ± 0.5, left ventricular ejection fraction 29.4 ± 7.9%, N-terminal pro-brain natriuretic peptide, NT-proBNP, level 2,209 ± 3,315 pg/ml) without sleep-disordered breathing (SDB; Apnea-Hypopnea Index, AHI, <5/h) or various degrees of CSA, documented by in-hospital cardiorespiratory polygraphy or polysomnography.
  
  
  RESULTS
  The CRP concentration in CHF patients was 0.550 ± 0.794 mg/dl in patients without SDB (AHI 0-4/h, n = 403) versus 0.488 ± 0.708 mg/dl in patients with mild CSA (AHI 5-14/h, n = 123, p = n.s.) and 0.660 ± 0.963 mg/dl in patients with moderate CSA (AHI 15-29/h, n = 160, p = n.s.). In patients with severe CSA (AHI ≥ 30/h, n = 280), significantly higher CRP concentrations were documented (0.893 ± 1.384 mg/dl, p < 0.05). Stepwise regression analysis revealed AHI, NT-proBNP and heart rate to be independently associated with elevated CRP levels.
  
  
  CONCLUSIONS
  Severe CSA in CHF patients is associated with elevated levels of CRP, a systemic marker of inflammation and cardiovascular risk. This might explain in part the negative prognostic impact of CSA in these patients.
authors.affiliation: Department of Cardiology, Heart and Diabetes Centre North Rhine-Westphalia, Ruhr University Bochum, Bad Oeynhausen, Germany.
authors.forename: Heidi
authors.initials: H
authors.lastname: Schmalgemeier
authors.forename: Thomas
authors.initials: T
authors.lastname: Bitter
authors.forename: Thomas
authors.initials: T
authors.lastname: Fischbach
authors.forename: Dieter
authors.initials: D
authors.lastname: Horstkotte
authors.forename: Olaf
authors.initials: O
authors.lastname: Oldenburg
mesh_terms: D000368:Aged; D002097:C-Reactive Protein / Q000378:metabolism*; D002639:Cheyne-Stokes Respiration / Q000097:blood* / Q000150:complications; D005260:Female; D006333:Heart Failure / Q000097:blood* / Q000150:complications; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D020182:Sleep Apnea, Central / Q000097:blood* / Q000150:complications
chemical_list: D002097:C-Reactive Protein