INCEPTION RCT – Early ECMO for Refractory Arrest

March 24, 2023

Corrected post with this change: The male- to-female ratio of patients in the Netherlands affected by cardiac arrest caused by ventricular arrhythmia is skewed and is 80:20.

Written by Kathryn Sulkowski

Spoon Feed
This multicenter randomized controlled trial (the INCEPTION trial), comparing ECPR vs conventional CPR for refractory cardiac arrest, showed no improvement in neurologically intact survival at 30 days.

Why does this matter?
Refractory cardiac arrest patients have notoriously poor outcomes. The introduction of ECMO and ECPR have raised the question of their potential utility in refractory cardiac arrest and limiting hypoxic brain injury due to prolonged arrest times. Two recent studies have shown conflicting evidence for the utility of ECPR: ARREST RCT – favorable; Prague OHCA group – no difference.

Early ECMO, another no go?
This was a multicenter, randomized, controlled trial in the Netherlands. Patients 18-70 years who received bystander CPR, had an initial ventricular arrhythmia, and had no ROSC at 15 minutes were randomized to receive ECPR or conventional CPR. At 30 days, 20% of the ECPR patients and 16% of the conventional CPR patients were alive with favorable neurological outcomes (measured using the Cerebral Performance Category score). This difference was not statistically significant.

There are limitations to this study which impact its applicability. The randomization design led to a large number of patients achieving ROSC prior to hospital arrival (patients were randomized during transport). With the intention-to-treat analysis, this could have contributed to there being no statistical difference between the groups. True blinding was impossible secondary to the study mechanics. Ninety percent of the patients were male; the male- to-female ratio of patients in the Netherlands affected by cardiac arrest caused by ventricular arrhythmia is skewed and is 80:20.

The authors cite that their approach to the study of ECPR and its application is pragmatic, in contrast to other trials. In assessing the utility of ECPR in out-of-hospital cardiac arrests, they point out that each system needs to critically assess its familiarity and expertise with ECPR, logistics of application, and overall caseload which likely all play a role in efficacy.

Peer Reviewed by Dr. Ketan Patel

Source
Early Extracorporeal CPR for Refractory Out-of-Hospital Cardiac Arrest. N Engl J Med. 2023 Jan 26;388(4):299-309. doi: 10.1056/NEJMoa2204511.

Editor note: This trial was powered to detect a 22% increase in the primary outcome assuming that the conventional CPR group would be at 8%. The control group doubled their estimate, leaving the trial severely underpowered. ~ Nick Zelt