Prognostic value of midregional pro-atrial natriuretic peptide in ventilator-associated pneumonia

Objective: This study aimed to investigate the correlation of midregional pro-atrial natriuretic peptide (MR-proANP) with severity of septic status in patients with ventilator-associated pneumonia (VAP) and the usefulness of MR-proANP for mortality prediction in VAP. Design: Prospective observational cohort study. Setting: University Hospital. Patients: Seventy-one patients consecutively admitted to ICU who developed VAP. Patients were followed for 28 days after diagnosis, when they were considered survivors. There were no interventions. Results: MR-proANP levels increased from sepsis to severe sepsis and septic shock on D0 and D4 of VAP (0.002 and 0.02 respectively). Median MR-proANP levels on day 0 and day 4 (pmol/L [interquartile range]) were 149.0 (79.8-480.0) and 249.0 (93.6-571.0) in septic patients, 438.5 (229.3-762.0) and 407.5 (197.8-738.0) in severe sepsis, 519.5 (369.5-1282.3) and 632.0 (476.0-1047.5) in septic shock. On day 0 and day 4, MR-proANP levels were significantly higher in non-survivors (525.0 [324.0-957.8] and 679.5 [435.0-879.5], respectively) than in survivors (235.0 [102.0-535.0] and 254.0 [110.0-571.0], respectively; P = 0.004). Univariate logistic regression model for mortality included age, gender, APACHE II score, creatinine, logarithmic transformed MR-proANP (LnMR-proANP). Mortality was directly related to LnMR-proANP on D0 and D4, with odds ratios (OR) of 2.06 (95% CI 1.21-3.51) and 2.63 (1.33-5.23), respectively. In multivariate logistic regression, only LnMR-proANP D0 with OR = 2.35 (1.05-5.26) and LnMR-proANP D4 with OR = 3.76 (1.39-10.18) remained significant. Conclusion: Our data demonstrated that MR-proANP levels increase progressively with the severity of sepsis and are independent predictors of mortality in VAP.