Research Highlights:
- In a small feasibility study of 39 patients in England, physician responders used a minimally invasive procedure called Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) to try to improve blood flow to the heart and brain during out-of-hospital cardiac arrest.
- Several key measures of circulation improved during resuscitation: the lower blood pressure number (which is particularly important for restarting the heart during CPR) increased 62%, the upper number (an important determinant of blood flow to the brain) rose 20%, and carbon dioxide in exhaled breath, an important sign of effective circulation during CPR, increased 50%.
- The technique is currently used in trauma centers to treat life-threatening internal bleeding and is now being explored as a potential way to improve outcomes after out-of-hospital cardiac arrest by prehospital professionals.
- Researchers said if future research shows that the technique can be delivered to patients earlier and on a wider scale, potentially by training advanced critical care paramedics, it could increase the chances of restarting the heart and ultimately save more lives.
- Note: The study featured in this news release is a research abstract. Abstracts presented at the American Heart Association's scientific meetings are not peer-reviewed, and the findings are considered preliminary until published as a full manuscript in a peer-reviewed scientific journal.
CHICAGO, Nov. 7, 2026 — A procedure to inflate a balloon in the body's largest artery to temporarily send more blood to the heart and brain may help improve the low chance of survival (1 in 10) for people who experience cardiac arrest outside of the hospital, according to new, independent, preliminary late-breaking science presented at the American Heart Association's Resuscitation Science Symposium 2026. The meeting will be held Nov. 7-8 in Chicago and will feature the most recent advances related to treating cardiopulmonary arrest and life-threatening traumatic injury.
"After cardiac arrest, people whose hearts cannot be restarted despite prolonged, high-quality resuscitation efforts, including CPR, breaths, use of an AED, medications and other techniques to restore the heartbeat, currently have very few treatment options and an extremely low chance of survival. Furthermore, survival and treatment options have not meaningfully increased in the last 50 years, so we need to do more in this area," said James Price, M.B.B.S., lead author of the study, who is a consultant emergency physician at Cambridge University Hospitals NHS Foundation Trust and consultant lead for research and development with the East Anglian Air Ambulance (EAAA) in Norwich, England.
During CPR (cardiopulmonary resuscitation) after cardiac arrest, only a fraction of normal blood flow is restored to vital organs, and death occurs either because the heart has not restarted or the brain is lacking oxygenated blood.
For the current feasibility study, investigators borrowed a technique used for the emergency control of internal bleeding. Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) is a minimally invasive procedure in which a small balloon is passed through an artery in the groin and inflated inside the aorta. When used for life-threatening internal bleeding, the temporary blockage reduces blood flow to areas of major bleeding below the balloon while maintaining blood flow to vital organs above it. The technique is most often used in trauma centers and is not routinely available in emergency medical services in either the United Kingdom or the United States.
Previously, laboratory studies confirmed the theory that REBOA in the upper part of the aorta (called Zone 1 – above the diaphragm) might send more blood to the brain and increase pressure from the aorta into the blood vessels that supply the heart muscle itself, making it an important technique to study in patients whose cardiac arrest had not responded to conventional advanced cardiac life support (ACLS) techniques.
The new study involves attempted use of REBOA by physicians of the East Anglian Air Ambulance helicopter emergency medical service after they arrived at out-of-hospital emergency sites — at the roadside or in the patient's home — when patients in cardiac arrest had not responded to ACLS including high-quality CPR, defibrillation when appropriate, medications, intubation to place a breathing tube in the airway and treatment of potentially reversible causes of the cardiac arrest. Researchers wanted to know whether REBOA could be deployed quickly and safely and improve blood flow to the heart and brain.
What are study's key findings?
In the 2-year feasibility study, the researchers successfully used REBOA to block the upper aorta in 33 of the 36 patients, with the procedure taking about 7 minutes from start to finish (with a median time from actual cardiac arrest to balloon inflation of 51 minutes).
Changes in patients after the REBOA procedure included:
- An immediate 59% increase in the aortic diastolic blood pressure (the lower number, which is particularly important for restarting the heart during CPR), from 26 to 42 mm Hg, reaching a maximum of 58 mm Hg (118% increase).
- A 20% increase in average systolic blood pressure (the upper number, an important determinant of blood flow to the brain), from 76 to 91 mm Hg.
- A 50% increase in the average amount of carbon dioxide measured in exhaled breath, an important indicator of blood flow through the lungs and the effectiveness of circulation during resuscitation.
- There were no serious adverse effects related to the procedures.
"Taken together, these findings suggest that aortic occlusion was redirecting blood flow towards the heart and brain as intended," Price said. "What surprised us most was the size of the physiological response despite the relatively late stage at which REBOA was performed in our study. To still see substantial improvements in blood pressure after such a prolonged period of cardiac arrest (average of 51 minutes after cardiac arrest) is really encouraging."
Although this preliminary study was not intended to assess changes in long-term patient outcomes, there were indications that survival might be enhanced by adding REBOA to other resuscitation and life support techniques, particularly in certain patient groups and when the procedure is done earlier after cardiac arrest:
- Overall, in 33 patients in which the balloon successfully blocked blood flow to the lower aorta (confirmed occlusion), 8 patients regained a sustained return of spontaneous circulation (pulse and effective circulation to hospital), and 2 survived and were discharged from the hospital with a good neurological outcome.
- In a subgroup of patients with witnessed cardiac arrest related to ventricular fibrillation (a life-threatening abnormal heart rhythm with rapid and uncoordinated contractions of the heart's lower pumping chambers) and who were treated with REBOA earlier (with occlusion achieved at a median of 44 minutes after cardiac arrest), 4 out of 5 regained a sustained return to spontaneous circulation, and 2 survived and were discharged from the hospital with a good neurological outcome.
- Although this was a very small sub-group of patients, these findings are particularly encouraging given that the chances of surviving with good brain function after such a prolonged cardiac arrest, despite repeated attempts at resuscitation, are normally extremely low.
"This study is an important first step, but it is not yet proof that REBOA saves lives. A key part of our additional work will be to understand which patients are more likely to benefit from this advanced technique and at what point in their resuscitation care," Price said. "These questions will need larger prospective studies with appropriate comparison groups and a focus on patient-centered outcomes rather than physiological measurements alone. Future research should also explore strategies for delivering the procedure earlier in resuscitation, potentially by expanding its use to specially trained non-physician emergency responders, such as advanced paramedics."
What are the study's details, background, design and limitations?
- Participants included 39 adults (average age of 59 years; 35 male and 4 female) experiencing out-of-hospital cardiac arrest who had not responded to standard advanced cardiac life support by the time helicopter emergency medical services arrived. The cardiac arrests resulted from medical conditions rather than injury.
- The study was conducted between June 2024 and June 2026 by the East Anglian Air Ambulance, in the Eastern region of England, United Kingdom.
- Patients received REBOA, a minimally invasive technique using a small balloon inserted through an artery in the groin and inflated in the upper part of the aorta to temporarily block blood flow to the lowest part of the body, if ongoing advanced cardiac life support was not successful.
- In addition to timing and safety information, data was collected on 3 measures that may indicate increased blood flow to the brain and heart muscle: aortic diastolic blood pressure, with numbers above 35 mmHg associated with a higher chance of restarting the heart; systolic blood pressure; and end-tidal carbon dioxide, the amount of carbon dioxide measured in exhaled breath, an important indicator of blood flow through the lungs and the effectiveness of circulation during resuscitation.
- This feasibility study did not include a control group and was not designed to determine if REBOA improves survival or long-term patient outcomes.
Co-authors, disclosures and funding sources are listed in the manuscript.
Statements and conclusions of studies that are presented at the American Heart Association's scientific meetings are solely those of the study authors and do not necessarily reflect the Association's policy or position. The Association makes no representation or guarantee as to their accuracy or reliability. Abstracts presented at the Association's scientific meetings are not peer-reviewed, rather, they are curated by independent review panels and are considered based on the potential to add to the diversity of scientific issues and views discussed at the meeting. The findings are considered preliminary until published as a full manuscript in a peer-reviewed scientific journal.
