The characteristics and prognostic importance of NT-ProBNP concentrations in critically ill patients

BACKGROUND: There are limited data for prognostic and diagnostic use of natriuretic peptides in intensive care unit (ICU) patients. We evaluate amino-terminal brain natriuretic peptide (NT-proBNP) in the medical ICU, specifically its correlation with noncardiac admission diagnosis and prognosis of critically ill patients. METHODS: NT-proBNP (pg/mL) was measured in 179 ICU patients without acute decompensated heart failure or acute coronary syndrome. Death during hospitalization ( mortality), APACHE II score, laboratory data, echocardiograms, medical history, and demographics were assessed. NT-proBNP concentrations were compared with established cutoffs for congestive heart failure (> 450 pg/mL for patients < 50 years of age, > 900 pg/mL for patients 50-70 years of age, and > 1800 pg/mL for patients > 70 years of age). Predictors of mortality and of NT-proBNP were analyzed by regression analysis. Tertiles were compared by analysis of variance and chi-squared test. RESULTS: NT-proBNP was elevated in these ICU patients (median 2139 pg/mL, 25(th) percentile 540 pg/mL, 75% percentile 7389 pg/mL). Severity of illness and renal dysfunction ( APACHE II score and serum creatinine) increased with rising NT-proBNP. The incidence of acute respiratory distress syndrome, sepsis, death, history of coronary artery disease (CAD) or congestive heart failure (all P <.05) increased with each tertile. Independent predictors of increased NT-proBNP were creatinine (P <=.001), CAD (P <.001), APACHE II score (P <.05), and sepsis (P <.001). Overall hospital mortality was 26%, and log NT-proBNP (P <.05), APACHE II (P <=.001), and CAD (P <.05) were independent predictors of mortality. CONCLUSIONS: For patients admitted to the ICU without decompensated heart failure or acute coronary syndrome, NT-proBNP concentrations are markedly elevated, especially in patients with sepsis. NT-proBNP strongly and independently predicts mortality. However, NT-proBNP should not be used to direct volume management in critically ill patients. (c) 2007 Elsevier Inc. All rights reserved.