Pro-atrial natriuretic peptide in patients with sepsis, severe sepsis and septic shock

Introduction

The natriuretic peptides are counter-regulatory hormones involved in volume homeostasis and cardiovascular remodeling. Both ANP and BNP are released by the heart in response to several stimuli, the most prominent of which being increased intravascular volume and increased intraventricular pressure. Recently, interest has focused on their significance in patients with sepsis and septic shock. A correlation between ANP and IL-6 was found in patients with septic shock [1].

Objectives

The present study aimed at examining: serum levels of the stable midregional prohormone forms of ANP in patients with sepsis, severe sepsis and septic shock; and correlations of proANP with cytokines involved in the pathogenesis of the sepsis.

Patients and methods

Serum concentrations of proANP were determined using the immunoluminometric assay in 17 consecutive patients admitted to the medical intensive care unit for sepsis (two patients) severe sepsis (five patients) and septic shock (10 patients). ProANP levels as well as those of procalcitonin, IL-6, IL-10 and lipopolysaccharide binding protein were measured at day 1 and in the course of the stay at the intensive care unit. ProANP was also determined in 12 healthy adults.

Results

The median APACHE II score of surviving patients was 18; minimum 5, maximum 25; of non-survivors median APACHE II score was 22.5; minimum 5, maximum 31 on day 1. Eight of the 17 patients died (47%). Significantly higher concentrations (P = 0.001) of proANP were measured in survivors (412.1 pmol/l; minimum 89; maximum 1486.1) and non-survivors (447.5 pmol/l; minimum 201.8; maximum 1876) as compared with controls (50.7 pmol/l; minimum 33.4; maximum 64.5). Significantly higher concentrations (733.8 pmol/l; minimum 201.8; maximum 1876) of proANP were in patients with severe sepsis and septic shock as compared with patients with sepsis (399.9 pmol/l; minimum 89; maximum 897), P = 0.0053. There were no differences of proANP levels between survivors and non-survivors. There was no significant correlation between proANP and cytokine levels measured simultaneously.

Conclusions

ProANP levels are elevated in the course of sepsis, severe sepsis and septic shock. The ANP levels do not correlate with the levels of PCT, IL-6, IL-10, LBP.