Prehospital resuscitative endovascular balloon occlusion of the aorta in non-traumatic out-of-hospital cardiac arrest (REBOARREST): an international, multicentre, open label, pragmatic, randomised, controlled trial.

BACKGROUND: Most patients with out-of-hospital cardiac arrest do not achieve sustained return of spontaneous circulation (ROSC). Resuscitative endovascular balloon occlusion of the aorta (REBOA) may increase blood pressure proximal to the ballon. If this technique is used during advanced life support (ALS), and occlusion is performed in the thoracic aorta, it may augment aortic pressure and coronary perfusion pressure. We investigated whether prehospital REBOA as an adjunct to ALS increased the rate of ROSC.

METHODS: REBOARREST was a pragmatic, parallel-group, multicentre, randomised controlled trial conducted at 12 sites in Norway, Denmark, and Italy. Adult patients (18-80 years) with non-traumatic out-of-hospital cardiac arrest were randomly assigned (1:1) to either a control group that received ALS or to an intervention group that received ALS combined with REBOA as an adjunct. Fulfilment of eligibility criteria was determined by the physician on scene and sealed envelopes were used to allocate patients. The statistician that performed the analyses was blinded for group allocation. The primary outcome was sustained ROSC, defined as lasting ≥ 20 min, assessed in the intention-to-treat population.

RESULTS: From June 7, 2021, to June 28, 2025, 200 patients were randomly assigned to the study groups. Due to lack of consent 21 patients dropped out of the trial, hence data from 179 patients are presented, 88 in the intervention group and 91 in the control group. Most patients were male (76%), with median age of 68 years (IQR 58-74). Median time from arrest to randomisation was 33 min (IQR 23-39) in the intervention group and 29 min (IQR 23-38) in the control group. Twenty-five of 88 patients (28%) in the intervention group and 24 of 91 patients (26%) in the control group achieved sustained ROSC (adjusted risk difference 1.8% [-11, 15, 95% CI], p = 0.78). Adverse events were registered in 19 patients.

CONCLUSIONS: Among patients with non-traumatic out-of-hospital cardiac arrest, a strategy of prehospital deployment of REBOA as an adjunct to ALS was feasible but did not significantly improve rates of sustained ROSC compared to ALS alone. Deployment of prehospital REBOA is safe and manageable in a two-person team with low procedure time.

TRIAL REGISTRATION: Clinicaltrials.gov ID NCT04596514. Registered 22.10.2020.