title: Intraindividual variation of amino-terminal pro-B-type natriuretic peptide levels in patients with stable heart failure.
abstract: This study aimed to evaluate how large the variation between measurements of N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) can be in patients with clinically stable heart failure (HF). The fluctuation of NT-pro-BNP in patients with HF has not been previously evaluated. Patients with chronic, stable HF were evaluated at 3-week intervals. The relative (percentage of baseline) difference between the 2 NT-pro-BNP measurements and their mean were calculated. In total, 118 double measurements of NT-pro-BNP were obtained. Changes in NT-pro-BNP measurements were determined according to quartiles of mean NT-pro-BNP. The median baseline NT-pro-BNP level was 1,323 pg/ml (25th and 75th percentiles 433 and 2,258), and the median second NT-pro-BNP level was 1,394 pg/ml (25th and 75th percentiles 475 and 2,353) (p = 0.34). Among pairs of measurements in the first quartile (NT-pro-BNP <450 pg/ml), the 5th and 95th percentiles of the distribution of relative differences were -86% and +197%. In the second (450 to 1,300 pg/ml), third (1,300 to 2,300 pg/ml), and fourth (>2,300 pg/ml) quartiles, the 5th and 95th percentiles of relative differences were -42% and +78%, -29% and +38%, and -30% and +37%, respectively, of the baseline values. In conclusion, the results support the clinical use of NT-pro-BNP in the monitoring of patients with HF with NT-pro-BNP levels >1,300 pg/ml. In these patients, variations between 1/3 less and about 40% more can be expected without clinical improvement or deterioration.
authors.affiliation: Serviço de Medicina Interna, Hospital S. João, Faculdade de Medicina da Universidade do Porto, Unidade I&D Cardiovascular do Porto, Porto, Portugal. pauloaraujo@netc.pt
authors.forename: José Paulo
authors.initials: JP
authors.lastname: Araújo
authors.forename: Ana
authors.initials: A
authors.lastname: Azevedo
authors.forename: Patrícia
authors.initials: P
authors.lastname: Lourenço
authors.forename: Francisco
authors.initials: F
authors.lastname: Rocha-Gonçalves
authors.forename: António
authors.initials: A
authors.lastname: Ferreira
authors.forename: Paulo
authors.initials: P
authors.lastname: Bettencourt
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D005260:Female; D006333:Heart Failure / Q000097:blood* / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D015588:Observer Variation; D010446:Peptide Fragments / Q000097:blood*
chemical_list: D015415:Biomarkers; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain