Pilot Trial Evaluating Mid-Regional Pro-Atrial Natriuretic Peptide as a Marker of Sepsis after Abdominal Surgery

Abstract

Mid-regional pro-atrial natriuretic peptide (MR pro-ANP) has been shown to be a diagnostic marker for sepsis. The objective of this pilot study was to evaluate the potential of MR pro-ANP in the diagnosis of postoperative sepsis. We enrolled 18 patients with postoperative sepsis, 19 patients who underwent major abdominal surgery without sepsis and 9 healthy individuals as control subjects. MR pro-ANP, interleukin-6 (IL-6) and procalcitonin (PCT) were measured on the day of inclusion in the study, and at days 3, 7 and 10. The mean levels of MR pro-ANP were significantly higher in patients with postoperative sepsis than in patients without sepsis (two-way ANOVA p <0.0001). The best cut-off level for MR pro-ANP was determined to be 162.5 pmol/l, with a sensitivity of 100% and specificity of 68%. On the day of inclusion in the study, MR pro-ANP detected postoperative sepsis equally as well as PCT (Youden test P = 0.17). MR pro-ANP levels in patients with postoperative sepsis remained significantly elevated for 10 days, regardless of the clinical state, whereas falling levels of IL-6 and PCT indicated improvement of sepsis. The overall correlation of MR pro-ANP with IL-6 and PCT was therefore low (Pearson´s r 0.15 and 0.36, respectively). MR pro-ANP may contribute to the diagnosis of postoperative sepsis, as its level can differentiate between elevation of other inflammatory markers due to abdominal surgery alone or postoperative sepsis.