Pro-atrial natriuretic peptide is a prognostic marker in sepsis, similar to the APACHE II score:: an observational study

Introduction Additional biomarkers in sepsis are needed to tackle the challenges of determining prognosis and optimizing selection of high-risk patients for application of therapy. In the present study, conducted in a cohort of medical intensive care unit patients, our aim was to compare the prognostic value of mid-regional pro- atrial natriuretic peptide (ANP) levels with those of other biomarkers and physiological scores. Methods Blood samples obtained in a prospective observational study conducted in 101 consecutive critically ill patients admitted to the intensive care unit were analyzed. The prognostic value of pro- ANP levels was compared with that of the Acute Physiology and Chronic Health Evaluation (APACHE) II score and with those of various biomarkers ( i.e. C-reactive protein, IL-6 and procalcitonin). Mid-regional pro- ANP was detected in EDTA plasma from all patients using a new sandwich immunoassay. Results On admission, 53 patients had sepsis, severe sepsis, or septic shock, and 68 had systemic inflammatory response syndrome. The median pro- ANP value in the survivors was 194 pmol/l ( range 20 - 2000 pmol/l), which was significantly lower than in the nonsurvivors ( median 853.0 pmol/l, range 100 - 2000 pmol/l; P < 0.001). On the day of admission, pro- ANP levels, but not levels of other biomarkers, were significantly higher in surviving than in nonsurviving sepsis patients ( P = 0.001). In a receiver operating characteristic curve analysis for the survival of patients with sepsis, the area under the curve (AUC) for pro- ANP was 0.88, which was significantly greater than the AUCs for procalcitonin and C-reactive protein, and similar to the AUC for the APACHE II score. Conclusion Pro-ANP appears to be a valuable tool for individual risk assessment in sepsis patients and for stratification of high-risk patients in future intervention trials. Further studies are needed to validate our results.