Can N-terminal pro-B-type natriuretic peptide and troponin T predict ICU and hospital mortality in patients with septic shock?

Introduction

The counter-regulatory neurohormone N-terminal pro-B-type natriuretic peptide (NT-proBNP) is predominantly released from the left ventricle in response to increasing wall tension and is a useful prognostic marker in patients with-established cardiac failure [1]. Myocardial dysfunction commonly occurs in septic patients. Cardiac biomarkers, including NT-proBNP, have been shown to be predicators of mortality in unselected critically ill patients [2].

Objectives

To evaluate the role of NT-proBNP and troponin T (TnT) as predictors of mortality in patients with severe sepsis and septic shock.

Methods

A prospective observational study was carried out on patients admitted to a noncardiothoracic tertiary ICU within 24 hours of the development of severe sepsis or septic shock. Plasma samples were taken on all patients on admission. NT-proBNP and TnT were determined using commercially available assays. Data were compared after logarithmic transformation, where appropriate.

Results

Thirty-four patients met the entry criteria (mean age 61.3 ± 14.9 years, male n = 19, all patients were mechanically ventilated). The APACHE II score of ICU survivors (median [range]) was 19 (12–33) and for nonsurvivors was 22.5 (14–38) (P = 0.19). Of the 34 patients, 11 died during their ICU admission (32%). Hospital mortality was 15/34 (44%). NT-proBNP was elevated (>150 ng/l) in all patients and TnT (>0.1 ng/ml) in 13 patients. Results are summarised in Table 1.

Table 1 ICU and hospital outcomes related to admission NT-proBNP and TnT levels

Conclusion

NT-pro-BNP and TnT are frequently elevated in severe sepsis. However admission values are not prognostic markers of ICU and hospital survival.