title: B-type natriuretic peptide versus amino terminal pro-B type natriuretic peptide: selecting the optimal heart failure marker in patients with impaired kidney function.
abstract: BACKGROUND
  The effect of impaired kidney function on B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) is vague. This study was performed to examine the effect of kidney dysfunction on the afore-mentioned markers and determine appropriate cutoffs for systolic heart failure (SHF).
  
  
  METHODS
  In this cross sectional study adults with estimated glomerular filtration rate (eGFR) <60 ml/min for ≥3 months were identified in consulting clinics from June 2009 to March 2010. SHF was defined as documented by a cardiologist with ejection fraction of < 40% and assessed by New York Heart Association classification (NYHA). Plasma was assayed for creatinine (Cr), BNP and NT-proBNP.
  
  
  RESULTS
  A total of 190 subjects were enrolled in the study, 95 with and 95 without SHF. The mean age of patients was 58 (±15) years, 67.4% being males. Mean BNP levels showed a 2.5 fold and 1.5 fold increase from chronic kidney disease (CKD) stage 3 to stage 5 in patients with and without SHF respectively. NT-proBNP levels in non-heart failure group were 3 fold higher in CKD stage 5 compared to stage 3. Mean NT-proBNP levels were 4 fold higher in CKD stage 5 compared to stage 3 in patients with SHF. Optimal BNP and NT-proBNP cutoffs of SHF diagnosis for the entire CKD group were 300 pg/ml and 4502 pg/ml respectively.
  
  
  CONCLUSIONS
  BNP and NT-proBNP were elevated in kidney dysfunction even in the absence of SHF; however the magnitude of increase in NT-proBNP was greater than that of BNP. BNP and NT-proBNP can be useful in diagnosing SHF, nonetheless, by using higher cutoffs stratified according to kidney dysfunction. NT-proBNP appears to predict heart failure better than BNP.
authors.affiliation: Department of Pathology & Microbiology, Aga Khan University, Stadium Road, P.O. Box 3500, Karachi 74800, Pakistan.
authors.forename: Lena
authors.initials: L
authors.lastname: Jafri
authors.forename: Waqar
authors.initials: W
authors.lastname: Kashif
authors.forename: Javed
authors.initials: J
authors.lastname: Tai
authors.forename: Imran
authors.initials: I
authors.lastname: Siddiqui
authors.forename: Iqbal
authors.initials: I
authors.lastname: Azam
authors.forename: Hira
authors.initials: H
authors.lastname: Shahzad
authors.forename: Farooq
authors.initials: F
authors.lastname: Ghani
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D006333:Heart Failure / Q000097:blood* / Q000175:diagnosis* / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*; D051436:Renal Insufficiency, Chronic / Q000097:blood* / Q000175:diagnosis* / Q000453:epidemiology
chemical_list: D015415:Biomarkers; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain