title: Renal dysfunction is a confounder for plasma natriuretic peptides in detecting heart dysfunction in uremic and idiopathic dilated cardiomyopathies.
abstract: BACKGROUND
  The diagnostic value of natriuretic peptides in uremic cardiomyopathy has not been defined, nor has the effect of a hemodialysis (HD) session on peptides.
  
  
  METHODS
  We performed an observational study of 100 white adult outpatients in New York Heart Association class I-II, with neither diabetes nor ischemic heart disease, 50 of whom had idiopathic dilated cardiomyopathy (DCM) and 50 of whom had uremic cardiomyopathy and were undergoing HD. We measured plasma N-terminal proB-type natriuretic peptide (NT-proBNP), BNP, and atrial natriuretic peptide (ANP) both before and after a dialysis session. Doppler echocardiograms were evaluated. We performed multiple regression analysis on the logarithm of peptide concentrations using clinical, laboratory, and echocardio-Doppler data as explanatory variables.
  
  
  RESULTS
  Mean peptide concentrations were higher in the HD group, with an HD:DCM ratio of 25 for NT-proBNP and 5 for BNP and ANP. Peptides were correlated with each other (r > 0.85). After HD, NT-proBNP significantly increased by 14%, BNP decreased by 17%, and ANP decreased by 56%. Predialysis concentrations correlated with postdialysis values (r > 0.85). A multiple regression equation significantly fitted the observed peptide concentrations, both pre- and postdialysis, using the same set of 4 variables: disease group (DCM or HD), diastolic pattern, left atrial volume, and body mass index.
  
  
  CONCLUSIONS
  Renal dysfunction was a confounder for natriuretic peptides, which were present in higher concentrations in the uremic patients with milder cardiac dysfunction than in those with idiopathic DCM without renal dysfunction. Left diastolic function pattern and atrial volume were cardiac determinants of peptide concentrations in DCM and HD.
authors.affiliation: Division of Nephrology, University Hospital, University of Padova, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: Codognotto
authors.forename: Antonio
authors.initials: A
authors.lastname: Piccoli
authors.forename: Martina
authors.initials: M
authors.lastname: Zaninotto
authors.forename: Monica
authors.initials: M
authors.lastname: Mion
authors.forename: Mario
authors.initials: M
authors.lastname: Plebani
authors.forename: Ugo
authors.initials: U
authors.lastname: Vertolli
authors.forename: Francesco
authors.initials: F
authors.lastname: Tona
authors.forename: Luisa
authors.initials: L
authors.lastname: Ruzza
authors.forename: Agata
authors.initials: A
authors.lastname: Barchita
authors.forename: Giovanni M
authors.initials: GM
authors.lastname: Boffa
mesh_terms: D009320:Atrial Natriuretic Factor / Q000097:blood*; D002311:Cardiomyopathy, Dilated / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D015986:Confounding Factors, Epidemiologic; D003430:Cross-Sectional Studies; D005260:Female; D005919:Glomerular Filtration Rate; D006321:Heart / Q000503:physiopathology*; D006801:Humans; D007668:Kidney / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*; D012044:Regression Analysis; D006435:Renal Dialysis; D014511:Uremia / Q000453:epidemiology / Q000503:physiopathology*
chemical_list: D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain; D009320:Atrial Natriuretic Factor