Plasma atrial natriuretic peptide and brain natriuretic peptide are increased in septic shock: impact of interleukin-6 and sepsis-associated left ventricular dysfunction.

OBJECTIVE: Interest has recently focused on the use of neurohormonal markers such as atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) as indices of left ventricular systolic dysfunction and prognosis in heart failure. Also, peptides belonging to the interleukin-6 (IL-6) family have been shown to induce ANP and BNP secretion. We hypothesized that BNP and ANP spillover in the peripheral circulation reflects left ventricular dysfunction and IL-6 production in septic shock.

DESIGN AND SETTING: Retrospective, clinical study in the medical intensive care unit of a university hospital.

PATIENTS AND PARTICIPANTS: 17 patients with septic shock and 19 control subjects.

INTERVENTIONS: Collection of clinical and demographic data in relation to ANP, BNP, IL-6, and soluble TNF receptors (sTNF-R-p55, sTNF-R-p75) in plasma over a period of 4 days.

MEASUREMENTS AND RESULTS: In septic shock we found a significant increase in ANP (82.7+/-9.9 vs. 14.9+/-1.2 pg/ml) and BNP (12.4+/-3.6 vs. 5.5+/-0.7 pg/ml). Plasma ANP peaked together with IL-6. Peaks of ANP and IL-6 were significantly correlated (r=0.73; p<0.01). BNP was inversely correlated to cardiac index (r=-0.56; p<0.05).

CONCLUSIONS: ANP and BNP increase significantly in patients with septic shock. BNP reflects left ventricular dysfunction. ANP is related to IL-6 production rather than to cardiovascular dysfunction.