title: Urinary N-terminal prohormone brain natriuretic peptide excretion in patients with chronic heart failure.
abstract: BACKGROUND
  Urinary excretion is currently regarded as the main mechanism of elimination of N-terminal prohormone brain natriuretic peptide (NT-proBNP). The clinical implications and the value of measurement of urinary NT-proBNP in patients with heart failure are largely unknown.
  
  
  RESULTS
  We studied 94 patients (age, 58+/-11 years; 79% men) with chronic heart failure (CHF) and 20 age- and sex-matched healthy control subjects. Glomerular filtration rate and effective renal plasma flow were measured as clearance of (125)I-iothalamate and (131)I-hippuran, respectively. NT-proBNP levels were determined in both plasma and 24-hour urine collections. Mean left ventricular ejection fraction of CHF patients was 0.28+/-0.09. Plasma NT-proBNP levels were higher in CHF patients compared with control subjects (median, 547 versus 41 pg/mL; P<0.001). Urinary NT-proBNP excretion, however, was substantially lower in CHF patients (median, 0.13 versus 2.3 mL/min; P<0.001). Urinary NT-proBNP excretion was independent of estimated glomerular filtration rate. In both CHF patients and control subjects, there was a strong and inverse relation between plasma NT-proBNP concentrations and urinary NT-proBNP excretion (r=-0.72 and r=-0.65 respectively; both P<0.001). Decreased renal plasma flow in CHF was significantly associated with a lower excretion of NT-proBNP (P=0.026).
  
  
  CONCLUSIONS
  Urinary NT-proBNP excretion is lower in patients with CHF compared with control subjects and is inversely related to plasma NT-proBNP. Urinary NT-proBNP is associated with renal plasma flow but not with estimated glomerular filtration rate. Elevated levels of plasma NT-proBNP in patients with CHF might be explained not only by myocardial stress but also by a marked decrease in urinary excretion.
authors: Department of Cardiology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
authors: Gerard C M
authors: GC
authors: Linssen
authors: Kevin
authors: K
authors: Damman
authors: Hans L
authors: HL
authors: Hillege
authors: Gerjan
authors: G
authors: Navis
authors: Dirk J
authors: DJ
authors: van Veldhuisen
authors: Adriaan A
authors: AA
authors: Voors
mesh_terms: D000368:Aged; D002908:Chronic Disease; D005260:Female; D005919:Glomerular Filtration Rate; D006333:Heart Failure / Q000150:complications* / Q000503:physiopathology / Q000652:urine*; D006801:Humans; D007457:Iodine Radioisotopes; D007483:Iothalamic Acid; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood / Q000652:urine*; D010446:Peptide Fragments / Q000097:blood / Q000652:urine*; D011877:Radionuclide Imaging; D012079:Renal Circulation; D051437:Renal Insufficiency / Q000000981:diagnostic imaging / Q000209:etiology* / Q000652:urine*; D014556:Urine
chemical_list: D007457:Iodine Radioisotopes; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain; D007483:Iothalamic Acid