Prognostic Role of NT-ProBNP in Out-Of-Hospital Cardiac Arrest

Introduction: The role of cardiac biomarkers in patients after out-of-hospital cardiac arrest (OHCA) has been subject to recent research due to myocardial stress and injury associated with cardiac arrest. However, it remains unclear to what extent NT-proBNP can be used as a prognostic tool after OHCA. Hypothesis: Baseline NT-proBNP is an independent predictor of mortality in patients after OHCA. Methods: Multicenter retrospective observational cohort study including non-traumatic OHCA patients presenting from 2/1/2017 to 4/1/2019. Relationship between NT-proBNP quartiles and mortality was assessed through unadjusted and adjusted (age, gender, presenting rhythm) analyses with logistic regression. Results: Baseline NT-proBNP values were obtained for 283 patients on presentation after OHCA with median 965 pg/mL (IQR 157-3550). Levels did not differ by arrest etiology (cardiac vs noncardiac) or presenting rhythm. NT-proBNP levels correlated with age (r = 0.44, p<0.0001), but not with lactate, CPR duration, or intra-arrest epinephrine. Overall in-hospital mortality was 68% (196/283). Mortality increased in a stepwise fashion among patients in increasing quartiles of NT-proBNP level (Figure). Mortality rate in Q1: 59% ( 42/71), Q2: 61% (43/70), Q3: 75% (54/72), Q4: 77% (54/70). Odds Ratios (OR) vs Q1 as reference: Q2 OR 1.10 [95% CI 0.56-2.17] p= 0.48; Q3 OR 2.08 [95% CI 1.01-4.17] p= 0.045; Q4 OR 2.33 [95% CI 1.11-4.76] p=0. 023. After adjusting for age, gender, and shockable rhythm there remained a stepwise relationship between higher mortality with increasing NT-proBNP quartile (Q2 OR 1.30 [95% CI 0.61-2.78] p= 0.78; Q3 OR 2.33 [95% CI 1.05-5.26] p= 0.038; Q4 OR 2.50 [95% CI 1.05-5.88] p= 0.039). Conclusion: In this multicenter cohort of patients with shockable and nonshockable OHCA, increased levels of NT-proBNP were predictive of an increased risk of in-hospital mortality even after adjustment for age, gender, and presenting rhythm.