The treatment program involving the life support machine called extracorporeal membrane oxygenation (ECMO) proved so much more effective than the standard treatment for this usually fatal condition that the trial was stopped early after enrolling just 30 of the expected 165 patients.
The study, known as the Advanced Reperfusion Strategies for Refractory Cardiac Arrest (ARREST) trial, was funded by the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of Health. It found that using ECMO as part of a broader program of care for cardiac arrest resulted in the survival of six of 14 patients compared with just one of 15 patients receiving standard treatment. Standard care for cardiac arrest typically includes cardiopulmonary resuscitation (CPR), defibrillation, intubation, and intravenous medications.
“This is the first trial to show a significant difference in outcomes after hospital admission among patients treated for out-of-hospital cardiac arrest with a team-based ECMO strategy,” said George Sopko, M.D., M.P.H., program director in the NHLBI’s Division of Cardiovascular Sciences. “We can improve outcomes for this common health condition, and we believe this study is a significant step in that direction.”
Approximately 340,000 people die of cardiac arrest each year in the United States. The condition occurs when the heart suddenly stops beating. There is no blood flow to the body, including the heart and brain. Immediate emergency treatment is essential to prevent death, but standard treatments are only marginally effective. Less than 10% of people who suffer a cardiac arrest survive. Some cardiac arrest patients do not respond to any standard cardiac arrest treatments.
The ARREST investigators, led by Demetris Yannopoulos, M.D., a cardiologist and professor of medicine at the Center for Resuscitation Medicine at the University of Minnesota Medical School in Minneapolis, hypothesized that this was because these patients had severe and extensive blockages in the arteries to their heart. To find out what approach might help cardiac arrest patients, the ARREST trial compared standard treatment with treatment with ECMO as soon as possible in 30 people who suffered a cardiac arrest. The average age was 61, and 25 of the 30 patients were men.
The ECMO machine connects to a patient by tubes inserted in an artery and vein in the groin. The machine pulls blood out of the patient’s body, pumps it through a part of the machine that acts as an artificial lung, and then returns it back to the body. This gives doctors time to stabilize the patient and, if suitable, clear any blockages in the arteries of the heart.
Six of the 14 people in ARREST who received ECMO (one of the ECMO patients declined to be included in the study) survived to hospital discharge compared with only one of the 15 who received standard treatment. At three and six months after hospital discharge, all six people who received ECMO were alive and well compared with none of the patients who received standard treatment. The investigators noted that the substantial improvement in survival among those treated with ECMO was due to the full team-based program of care implemented around it, not ECMO alone. That team program included protocols for emergency medical services to identify patients who might benefit most from it, rapid transport to a hospital, rapid communication with an ECMO center to mobilize experienced operators who do a high volume of ECMO procedures, and protocols for care after the patient is resuscitated. ECMO was only one part of this treatment plan.
“The findings from the trial make an important statement that early implementation of ECMO is the enabling and necessary condition that allows further advanced targeted therapies to be delivered in those critical patients. In its absence, the life-saving treatment that follows is just not possible,” said Yannopoulos.
“The favorable survival rate in this study is very encouraging and is helping to pioneer new pathways in advanced cardiac care and transform outcomes for patients with cardiac arrest,” said Tom P. Aufderheide, M.D., ARREST co-investigator, senior study author, and professor and director of the Resuscitation Research Center at the Medical College of Wisconsin, Milwaukee.
Because of this notable improvement in survival of patients receiving this program of care, ARREST’s Data and Safety Monitoring Board recommended in June that the study be halted. However, researchers continued to monitor the survivors and found that the majority treated under the ECMO program improved both functionally and neurologically for six months and then returned to a near-normal life.
The investigators have continued to follow up on the patients and plan to conduct a full analysis of the data, including looking at longer-term outcomes and costs of care. Those results, they said, will be released in subsequent publication of study results. In a separate study, the investigators report outcomes from the University of Minnesota’s ECMO-facilitated resuscitation program that serves the Minneapolis-St. Paul metropolitan area.
