ARREST: ECMO-facilitated protocol improves survival in out-of-hospital cardiac arrest
A protocol with extracorporeal membrane oxygenation-facilitated resuscitation improved survival in patients with out-of-hospital cardiac arrest vs. standard advanced cardiac life support, according to results of the ARREST trial.
The trial, planned for 150 patients, was stopped after 30 patients were enrolled because the extracorporeal membrane oxygenation (ECMO) group had dramatically better survival rates than the standard group, Demetris Yannopoulos, MD, professor of medicine in the Center for Resuscitation Medicine at the University of Minnesota Medical School, said during a presentation at the virtual American Heart Association Scientific Sessions.
The results were simultaneously published in The Lancet.
“Standard resuscitation strategies are inefficient as the duration of CPR increases,” Yannopoulos said during his presentation. “Survival is grim after 30 minutes of CPR, even in patients with initial shockable rhythms.”
The researchers enrolled patients aged 18 to 75 years (mean age, 59 years; 83% men) who had out-of-hospital cardiac arrest with an initial shockable rhythm of ventricular tachycardia or ventricular fibrillation, no return of spontaneous circulation after three shocks, the body morphology to accommodate an automated CPR device and an estimated transfer time of less than 30 minutes to the University of Minnesota Medical Center.
Patients assigned to the ECMO group who had no return of spontaneous circulation had ongoing CPR during transport to the cath lab. They were then assessed for three resuscitation discontinuation criteria: end-tidal carbon dioxide less than 10 mm Hg upon arrival; arterial partial pressure of oxygen less than 50 mm Hg or oxygen saturation less than 85%; and serum lactate greater than 18 mmol/L, Yannopoulos said. Patients who had more than one of those criteria had resuscitation terminated and were declared dead. Patients who had one or none of those criteria received venous arterial ECMO and, if appropriate, coronary angiography and PCI. Advanced life support was continued for up to 90 minutes after ECMO. Patients who had sustained organized electrical rhythm after those 90 minutes were admitted to the cardiac care unit, and those who had not were declared dead.
Patients assigned to the ECMO group who had return of spontaneous circulation were given coronary angiography and PCI if appropriate, and were given venoarterial ECMO or another circulatory support device if clinically unstable. They were then admitted to the cardiac care unit.
Patients assigned to the standard group were given standard advanced cardiac life support for 60 minutes from the 911 call and 15 minutes from arrival to the ED. Those who had no return of spontaneous circulation during that time and were deemed futile by the ED physician were pronounced dead, Yannopoulos said. Those who had return of spontaneous circulation and were clinically stable were given angiography and PCI. Those who were not clinically stable were considered for venoarterial ECMO or another circulatory support device.
For the first 30 patients enrolled, the primary outcome of survival to hospital discharge was 7% of the standard group and 43% of the ECMO group (risk difference, 36.2 percentage points; 95% CI, 3.7-59.2; posterior probability of ECMO superiority = 0.9861), according to the researchers.
Survival at 6 months was also greater in the ECMO group (ECMO, 43%; standard, 0%; HR = 0.16; 95% CI, 0.06-0.41; log-rank P < .0001), Yannopoulos said.
“Early ECMO-facilitated resuscitation for refractory ventricular fibrillation out-of-hospital cardiac arrest significantly improved survival to hospital discharged compared to standard advanced cardiac life support treatment,” Yannopoulos said during the presentation. “Functional status of survivors at 3 and 6 months post-discharge was favorable, consistent with our prior published work.”
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Yannopoulos D, et al. Featured science: Cardiac procedural innovation for special patient groups. Presented at: American Heart Association Scientific Sessions; Nov. 13-17, 2020 (virtual meeting).