N-terminal pro-B-type natriuretic peptide is an independent predictor of outcome in an unselected cohort of critically ill patients

Abstract

Objectives: Natriuretic peptides emerged during recent years as potent prognostic markers in patients with heart failure and acute myocardial infarction. In addition, natriuretic peptides show strong predictive value in patients with pulmonary embolism, sepsis, renal failure, and shock. The present study tests the prognostic information of N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) in an unselected cohort of critically ill patients.

Design: Prospective, observational study.

Setting: A tertiary intensive care unit in a university hospital.

Patients: A total of 289 consecutive patients admitted to the intensive care unit during a 16-month period with the following data: age 64 +/- 14 yrs, male n = 191, Simplified Acute Physiology Score II of 52 +/- 24, mechanical ventilation n = 180 (62%), vasopressors n = 179 (62%), renal failure n = 24 (8%).

Interventions: None.

Measurements and main results: Plasma NT-pro-BNP samples (Roche Diagnostics) were obtained on intensive care unit admission. Data are given as median [range]. Intensive care unit survivors had significantly lower NT-pro-BNP values compared with intensive care unit nonsurvivors (3394 [24-35,000] vs. 6776 [303-35,000] pg/mL, survivors vs. nonsurvivors, respectively, p = .001). Hospital survivors were characterized by significantly lower NT-pro-BNP values (2656 [24-35,000] vs. 8390 [303-35,000] pg/mL, survivors vs. nonsurvivors, respectively, p = .001). NT-pro-BNP levels were not significantly different in patients with primary cardiac diagnosis compared with those with a noncardiac admission diagnosis (4794 [26-35,000], n = 202 vs. 3349 [24-35,000], n = 87, cardiac vs. noncardiac, respectively, p = .28). In a logistic regression model, Simplified Acute Physiology Score II and NT-pro-BNP were independently associated with hospital survival (chi = 35.6, p = .0001 and chi = 11.3, p = .0008, Simplified Acute Physiology Score II and NT-pro-BNP, respectively). Areas under the receiver operating characteristic curves of NT-pro-BNP and Simplified Acute Physiology Score II were not statistically significant different regarding the prediction of outcome.

Conclusions: NT-pro-BNP on admission is an independent prognostic marker of outcome in an unselected cohort of critically ill patients. A single measurement of NT-pro-BNP might facilitate triage of emergency and intensive care unit patients.