Pro-B-type natriuretic peptide predicts mortality in critically ill patients

Background

Natriuretic peptides have emerged during recent years as potent prognostic markers in patients with heart failure and other cardiovascular diseases. Moreover, natriuretic peptides show strong predictive value in patients with pulmonary embolism, sepsis and renal failure. Also, first data imply that BNP is a good predictor of outcome in a selected population (shock) of critically ill patients.

Aim

To test the hypothesis that N-terminal pro-B-type natriuretic peptide (pro-BNP) serves as a prognostic marker in an unselected cohort of intensive care patients.

Design

A prospective, observational study at a tertiary ICU.

Methods

Eighty-one consecutive patients (age 63 ± 16 years, male n = 51, SAPS 2 score 49 ± 11, mechanical ventilation n = 50, vasopressors n = 56, renal failure n = 19, postoperative n = 23) admitted to the ICU during a 3-month period were evaluated. Plasma samples of all patients were obtained upon ICU admission. Pro-BNP was determined using commercially available kits (Roche Diagnostics). Subgroup analyses comprised main diagnosis (cardiologic/non-cardiologic and medical/postsurgery) and presence and category of shock. Data were compared after logarithmic transformation.

Results

Pro-BNP levels were significantly higher in patients who died (n = 17) than in ICU survivors (13,871 ± 19,869 vs 5304 ± 8211 pg/ml, n = 17 vs n = 64, P = 0.02). There was no significant difference in pro-BNP between cardiologic and other medical patients (9794 ± 14,379 vs 7099 ± 11,208, P = 0.91) but pro-BNP was significantly lower in postoperative patients (3671 ± 6600 vs 9131 ± 14,090 pg/ml, P = 0.045, surgical and medical patients, respectively). Patients presenting with shock showed significantly higher levels of pro-BNP (14,321 ± 17,653 vs 5264 ± 8605 pg/ml, P < 0.001); however, no difference was observed between cardiogenic and septic shock categories.

Conclusion

Pro-BNP might be a strong predictor of outcome even in an unselected population of critically ill patients.