We aimed to evaluate the effect of prolonged targeted temperature management (TTM) in patients with out-of-hospital cardiac arrest (OHCA) on the levels of midregional pro-atrial natriuretic peptide (MR-proANP) and N-terminal pro b-type natriuretic peptide (NT-proBNP) and assess their potential as prognostic biomarkers. A preplanned post hoc analysis of "Targeted temperature management for 48 h vs 24 h and neurologic outcome after out-of-hospital cardiac arrest: A randomized clinical trial (TTH48 trial)," where patients were randomized to TTM at 33°C ± 1°C of standard duration (24 hours) versus prolonged (48 hours). Blood samples were drawn from patients with OHCA at two Scandinavian university hospitals at admission to the ICU and at 24, 48, and 72 hours after reaching the target temperature. Primary outcome was levels of MR-proANP and NT-proBNP. Secondary outcome was cerebral performance category (CPC 1-5) at 6 months. Samples from 114 patients were analyzed. Prolonged TTM significantly decreased the levels of MR-proANP and NT-proBNP at 48 hours compared with standard 24 hours-TTM (p < 0.01). However, there were no significant differences at other time points. Patients with poor outcome (CPC 3-5) had a statistically significantly increased MR-proANP level at 24 hours (p < 0.01) and 72 hours (p < 0.01) compared with the good outcome group (CPC 1-2). Prognostic performance was best at 24 hours for both MR-proANP and NT-proBNP; with an AUC of 0.73 (confidence interval [95% CI]: 0.63-0.83) and 0.72 (95 % CI: 0.59-0.85), respectively. Prolonged TTM lowered the levels of both MR-proANP and NT-proBNP at 48 hours. MR-proANP may add prognostic information in postcardiac arrest patients. ClinicalTrials.gov ID: NCT01689077.
Keywords: MR-proANP; NT-proBNP; cardiac arrest; natriuretic peptide; prognostication; targeted temperature management.