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For out-of-hospital cardiac arrest (OHCA) that doesn't respond to initial resuscitation attempts, extracorporeal membrane oxygenation (ECMO) might improve survival, results of two studies published Friday suggested.

In a 30-patient , six of 14 patients randomized to early ECMO-facilitated resuscitation survived to hospital discharge compared with one of 15 patients treated with standard advanced cardiac life support (43% vs 7%).

Given the risk difference of 36.2% with a posterior probability of ECMO superiority of 0.9861 by Bayesian methods, the trial was terminated early for efficacy, Demetris Yannopoulos, MD, of the University of Minnesota in Minneapolis, reported at the virtual and simultaneously online in .

The same group also reported an identical survival rate when an ECMO intervention for OHCA was introduced in a community setting.

Despite long, complicated hospital stays that left ARREST trial survivors deconditioned and weak, their neurologic function was largely preserved, the group noted, citing "consistent recovery and improvement observed at the 3-months and 6-months follow-up visits, after physical therapy and rehabilitation was undertaken."

In the ECMO group, modified Rankin scores at 6 months were 3 for one patient, 2 for two patients, 1 for two, and 0 for one. The sole survivor in the standard care group did so with a modified Rankin score of 5 and died before the 3-month follow-up.

"Survival from cardiac arrest has remained poor for decades," the group noted, adding that their control group survival was on par with prior studies.

"ECMO-facilitated resuscitation... normalises perfusion reliably, provides cardiopulmonary support to facilitate identification and treatment of the most common cause of refractory arrest (severe coronary artery disease with chronic and acute coronary occlusion) with consistent access to the catheterisation laboratory for angiography and angioplasty when needed, and becomes the bridge to recovery in ICU when the multiorgan injury sustained during long resuscitation can otherwise lead to accelerated deterioration and death," the researchers noted.

"Therefore, it is important to note that early implementation of ECMO is the enabling and necessary condition that allows additional advanced targeted therapies to be delivered in these critical patients. In its absence, what follows is just not possible."

However, this strategy still needs to be proven definitively in a multicenter phase III trial before wider implementation, they acknowledged, "but only after programmes have matured and restructured the systemic responses to these patients."

In a , Yannopoulos and colleagues detailed the results after a similar program launched in the Minneapolis-St. Paul area with a 24/7 mobile ECMO cannulation team. It, too, achieved a rate at 3 months with Cerebral Performance Category 1 or 2 among the 58 patients treated who met the specified criteria.

Their early ECMO strategy was for OHCA with refractory ventricular fibrillation and no return of spontaneous circulation after three shocks in patients who received automated cardiopulmonary resuscitation with a Lund University Cardiac Arrest System and could be transferred to the hospital within 30 minutes.

Once there, patients were taken immediately to the cardiac cath lab regardless of pulse and, if arterial blood gas was favorable, they got peripheral veno-arterial ECMO support and an angiogram followed by revascularisation as clinically indicated.

The standard care patients stayed in the emergency department for at least 15 minutes of continued treatment or at least 60 minutes after the 911 call. Patients who achieved a pulse or spontaneous circulation at any point during resuscitation were transferred for angiography, angioplasty, and circulatory support as needed.

Those who survived to hospital admission were treated similarly in a dedicated cardiac ICU in both groups. CPR duration averaged close to 60 minutes.

Starting ECMO in the cath lab took advantage of interventional cardiologists' expertise in large bore percutaneous vascular access and the immediate availability of fluoroscopy and ultrasound vascular access guidance, which Yannopoulos's group noted adds a layer of safety and minimizes vascular access complications.

"This can serve as a model, but it is not the only potential successful approach," they wrote.