The prohormone of atrial natriuretic peptide (ANP) is elevated in severe sepsis and high levels are associated with poor outcome

The prohormone of calcitonin (procalcitonin, PCT) has gained vast importance as a new marker of systemic bacterial infection, and is now established as a routine biomarker in many intensive care settings. However, there is ample demand for additional biomarkers to tackle the challenges of sepsis prognosis and optimal stratification of high risk patients for potential therapies. We describe here an additional role for another prohormone: The prohormone of atrial natriuretic peptid (proANP).

We evaluated the prognostic value of proANP levels in a cohort of medical intensive care (ICU) patients as compared to other biomarkers and physiological scores. Blood samples of a prospective observational study in 101 consecutive critically ill patients admitted to the ICU were analysed. The prognostic value of proANP levels was compared to the Acute Physiology and Chronic Health Evaluation (APACHE II) score as well as to different biomarkers (i.e., C-reactive Protein [CRP], interleukin-6 [IL-6], procalcitonin [PCT]). proANP was detected in EDTA plasma of all patients with a new sandwich immunoassay (B.R.A.H.M.S Seristra®). On admission, 53 patients had sepsis, severe sepsis or septic shock and 68 had systemic inflammatory response syndrome (SIRS). The median proANP value in the group of survivors was 194 pmol/L (range 20.0 to 2000) which was significantly lower than in the group of non survivors (median 853.0 pmol/L, range 100.0 to 2000, p<0.001). On the day of admission, proANP levels, but not other biomarkers, were significantly higher in surviving as compared to non-surviving sepsis patients (p=0.001). In a receiver operating curve analysis for the survival of sepsis patients, the AUC for proANP was 0.88, which was significantly higher as compared to the AUCs of ProCT and CRP, and similar to the AUC of the APACHE II score.

ProANP seems to be a valuable tool for individual risk assessment of sepsis patients and stratification of high risk patients in future intervention trials. Further prospective studies are endorsed to validate our results