Abstract 10617: Antiarrhythmic Use and the Posterior Probability of Neurologically Intact Survival in a Reanalysis of the Amiodarone, Lidocaine or Placebo Study in Out-of-Hospital Cardiac Arrest

Abstract

Introduction: There are no randomized controlled trials (RCT) demonstrating improvement in neurologically intact survival from antiarrhythmic therapy given during out-of-hospital cardiac arrest (OHCA) from ventricular fibrillation/tachycardia (VF/VT). The Amiodarone, Lidocaine or Placebo Study in Out-of-Hospital Cardiac Arrest (ALPS) was an RCT of amiodarone, lidocaine or placebo whose primary end-point was survival to hospital discharge. We sought to estimate the posterior probability of the absolute risk difference of neurologically intact survival (modified Rankin Score ≤ 3) from antiarrhythmic use (amiodarone or lidocaine) compared to placebo and from the use amiodarone versus lidocaine. Methods: We performed a Bayesian reanalysis on the per-protocol population of the ALPS trial in order to calculate the posterior probability of neurologically intact survival. We derived prior probabilities from the Amiodarone for Resuscitation after Out-of-Hospital Cardiac Arrest Due to Ventricular Fibrillation (ARREST) and Amiodarone Compared with Lidocaine for Shock-Resistant Ventricular Fibrillation (ALIVE) trials. We considered a clinically meaningful absolute difference to be ≥ 1%. Results: The posterior median probability of the absolute difference in neurologically intact survival between antiarrhythmic therapy and placebo was 2.2% (95% credible interval of -0.15% to 4.7%). There is a 96% chance that antiarrhythmic improves neurologic outcome and 86% chance of a clinically meaningful improvement. The posterior median probability of the absolute difference in neurologically intact survival between amiodarone and lidocaine was 1.5% (95% credible interval -1.6% to 4.5%). Conclusion: The results of this Bayesian analysis of the ALPS trial using likely optimistic prior probabilities derived from the ARREST trial may help inform clinicians of the value of antiarrhythmic therapy in OHCA.