title: Variability of NT-proBNP plasma and urine levels in patients with stable heart failure: a 2-year follow-up study.
abstract: OBJECTIVE
  To examine N-terminal pro-brain natriuretic peptide (NT-proBNP) variability in plasma and urine samples of patients with stable heart failure (HF) during a 24-month follow-up.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Teaching hospital based study.
  
  
  METHODS
  74 clinically and functionally stable patients (NYHA class 2+/-0.5) out of 114 patients diagnosed with HF were followed up, and NT-proBNP plasma and urine levels were measured at baseline, 12 and 24 months.
  
  
  RESULTS
  Significant differences in mean urinary levels (p<0.01) were found during follow-up, but no changes were found in plasma. Bland-Altman plots showed few variations in plasma percentages in the three intervals (stage I-basal; stage II-stage I; stage II-basal) with a coefficient of reproducibility (CR) of 22%, 21% and 25%, respectively. Changes in NT-proBNP urinary levels had a CR of 7.1%, 6.8% and 9.4% at the three intervals, respectively. A good correlation was found between plasma and urinary levels of NT-proBNP (p<0.001) and between the different NT-proBNP plasma (p<0.001) and urine measurements (p<0.001).
  
  
  CONCLUSIONS
  NT-proBNP plasma and urine levels show good stability in a 24-month follow-up of patients with stable heart failure. Thus, assessment of urinary and plasma NT-proBNP concentrations may be a useful tool for monitoring patients with HF during follow-up. The results suggest that variations in peptide concentrations exceeding 22% in plasma and 7% in urine in a 12-month follow-up and 25% and 9% in a 24-month follow-up may indicate pathophysiological changes.
authors.affiliation: Cardiology Unit, Research Centre, Hospital Universitario La Fe, Valencia, Spain.
authors.forename: Raquel
authors.initials: R
authors.lastname: Cortés
authors.forename: Miguel
authors.initials: M
authors.lastname: Rivera
authors.forename: Antonio
authors.initials: A
authors.lastname: Salvador
authors.forename: Vicente
authors.initials: V
authors.lastname: Bertomeu
authors.forename: Fernando García
authors.initials: FG
authors.lastname: de Burgos
authors.forename: Esther
authors.initials: E
authors.lastname: Roselló-Lletí
authors.forename: Manuel
authors.initials: M
authors.lastname: Portolés
authors.forename: Rafael
authors.initials: R
authors.lastname: Payá
authors.forename: Luis
authors.initials: L
authors.lastname: Martínez-Dolz
authors.forename: Vicente
authors.initials: V
authors.lastname: Climent
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D015415:Biomarkers / Q000097:blood / Q000652:urine; D015150:Echocardiography, Doppler; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000401:mortality; D006801:Humans; D007118:Immunoassay; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D009017:Morbidity; D020097:Natriuretic Peptide, Brain / Q000032:analysis* / Q000097:blood / Q000652:urine; D010446:Peptide Fragments / Q000032:analysis* / Q000097:blood / Q000652:urine; D011498:Protein Precursors / Q000032:analysis* / Q000097:blood / Q000652:urine; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D015415:Biomarkers; D010446:Peptide Fragments; D011498:Protein Precursors; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain