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ECMO-resuscitation tied to better survival in out-of-hospital cardiac arrest

The Lancet
AHA 2020
Reuters Health - 18/11/2020 - Patients with out-of-hospital cardiac arrest and refractory ventricular fibrillation are far more likely to survive when treated with extracorporeal membrane oxygenation (ECMO)-facilitated resuscitation than with standard advanced cardiac life support (ACLS), a small trial finds.

With 6 out of 14 patients randomly assigned to receive ECMO surviving versus 1 of 15 who received standard ACLS, the benefits appeared so dramatic that the phase 2 trial was halted early after enrolling just 30 of the planned 165 patients, according to the report published in The Lancet and presented at the American Heart Association's Scientific Sessions 2020, held virtually this year.

The trial, known as the Advanced Reperfusion Strategies for Refractory Cardiac Arrest (ARREST), was funded by the National Heart, Lung and Blood Institute. NHLBI opted to end the trial after a unanimous recommendation from the Data and Safety Monitoring Board.

"Having an organized system of care that allows for the early identification of candidates that can be transferred quickly to an experienced ECMO center with centralized care similar to what is found at trauma or burn centers can significantly improve survival in this very grim disease prognosis state," said the study's lead author, Dr. Demetris Yannopoulos of the Center for Resuscitation Medicine at the University of Minnesota Medical School in Minneapolis.

While the machine itself makes a big difference, Dr. Yannopoulos told Reuters Health, he emphasized the importance of having a dedicated center and team available 24/7 to care for these patients, as well as a network of paramedics and community members who can provide CPR.

Although there were hints that ECMO might improve survival in certain cardiac arrest patients, there was no proof. To at least demonstrate that treatment with the machine was safe, Dr. Yannopoulos and his colleagues set up the trial.

The researchers enrolled all consecutive adults presenting to the University of Minnesota Medical Center, presumed or known to be between 18 and 75 years old with an initial rhythm of ventricular fibrillation or pulseless ventricular tachycardia, no return of spontaneous circulation (ROSC) after three defibrillation shocks, a body morphology able to accommodate a Lund University Cardiopulmonary Assist System, and an estimated transfer time to the emergency department shorter than 30 minutes. Exclusion criteria included: valid do-not-resuscitate orders; blunt or penetrating or burn related injury; drowning; and known overdose.

The 30 patients who were entered into the trial were randomized to receive treatment with either ECMO or ACLS. One patient in the ECMO group withdrew consent three days after randomization, which left 15 in the ACLS group and 14 in the ECMO group.

Just one patient from the ACLS group survived to discharge from the hospital, as compared with six in the ECMO group. Many patients in the ECMO group could not walk at the time of hospital discharge due to prolonged hospitalization and physical deconditioning, which reduced their functional scores. But those scores improved with time, physical rehabilitation and reconditioning and all had good functional assessment scores at six months.

The one survivor in the ACLS group died before the 3-month evaluation, which meant the researchers could not compare neurological status between the two groups.

There were complications in those who received ECMO. "As expected, serious multi-organ injury was frequent in the very critically ill population undergoing early ECMO, including cardiopulmonary resuscitation trauma, aspiration pneumonia, bleeding, cardiogenic shock, liver injury, and renal failure," Yannopoulos and his colleagues write.

At three and six months after hospital discharge, the six ECMO patients were alive and well.

Experts welcomed the new study and praised the authors' dedication.

"This is a very exciting, amazing and promising trial," said Dr. Umesh Gidwani, an associate professor of medicine and chief of cardiac critical care at the Zena and Michael A. Wiener Cardiovascular Institute at the Icahn School of Medicine at Mount Sinai in New York City. "This very solid trial is one of the few studies that will change the way we practice medicine."

While it would be best if a larger phase 3 trial could be performed, that's not likely, Dr. Gidwani said. "But researchers can do observational studies using historical controls," he added.

The new research is "remarkable work," said Dr. Zach Rhinehart, an assistant professor of medicine at the University of Pittsburgh School of Medicine and director for the UPMC Heart and Vascular Institute clinical program. "A lot of experts in the field wanted to believe ECMO would work but they were waiting on randomized data. I think this team should be commended for putting together such convincing evidence."

"I witnessed one of these," Dr. Rhinehart said. "Their team was exceptionally well coordinated pre-hospital and in the cath lab. I think all those factors contributed to their results."

One thing to keep in mind is that the treatment is "fraught with complications," Dr. Rhinehart said. "That being said, it's better having a complication and surviving than dying."

By Linda Carroll

SOURCE: https://bit.ly/32S4srZ The Lancet, online November 13, 2020, and https://bit.ly/3feqjyw AHA Scientific Sessions 2020.

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