UK-REBOA Trial: Innovative or Over-Inflated?

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Jansen JO, Hudson J, Cochran C, et al. Emergency Department Resuscitative Endovascular Balloon Occlusion of the Aorta in Trauma Patients With Exsanguinating Hemorrhage: The UK-REBOA Randomized Clinical Trial. JAMA. 2023;e2320850. PMID: 37824132

Hemorrhage is a major cause of preventable death in trauma patients, and early, expeditious, definitive hemorrhage control is a critical focus in trauma resuscitation. Theoretically, the use of REBOA (Resuscitative Endovascular Balloon Occlusion of the Aorta) with aortic occlusion should help limit hemorrhage, maintain cerebral and myocardial perfusion, and allow more time for interventional and surgical procedures. Military practice guidelines, along with ACEP and the American College of Surgeons, recommend REBOA for traumatic life-threatening hemorrhage below the diaphragm in patients with hemorrhagic shock who are unresponsive or transiently responsive to resuscitation. Despite these recommendations, the UK-REBOA trial is the first randomized clinical trial to compare REBOA to standard of care.

Clinical Question:
In trauma patients aged 16 years or older with life-threatening torso hemorrhage, does the use of REBOA and standard care (SC) compared to standard care alone (SCA) improve mortality at 90 days?
The UK-REBOA trial, which was stopped early due to a prespecified stopping rule for harm, randomized 90 patients (46 to REBOA+SC and 44 to SCA). The primary outcome showed higher mortality in the REBOA+SC group (54%) compared to the SCA group (42%), with an odds ratio (OR) of 1.58 (95% CI 0.72 – 3.52) and a posterior probability of OR > 1 at 86.9%. Secondary outcomes revealed increased odds of death at all time points in the REBOA+SC group, with more deaths due to bleeding (32% vs. 17%) and longer median times to definitive hemorrhage control (19 minutes longer) compared to the SCA group. Patients in the SCA group also had more intensive care unit-free and hospital-free days, with no significant differences in complications or serious adverse device events between the groups.
Key Points:
Small Sample Size:
The UK-REBOA trial’s findings are based on a small sample size, with only 46 patients randomized to the REBOA+SC arm and many protocol violations. Only 19 patients in this group underwent complete REBOA, while others had incomplete or no attempts at arterial access and balloon inflation. Early trial termination due to evidence of harm introduces the risk of overestimating the intervention’s effect. Baseline demographic differences persisted despite randomization, suggesting a worse prognosis for the REBOA+SC group. These factors, combined with the small sample size and early termination, raise the possibility that the results could be due to chance.

Protracted Treatment:
In the UK-REBOA trial, the timeliness of hemorrhage control was critical, but patients faced extended pre-hospital transit times exceeding 90 minutes. The REBOA+SC group experienced a median time to hemorrhage control 19 minutes longer than the SCA group, resulting in overall times approaching 3 hours. This delay likely contributed to higher mortality rates due to prolonged exsanguination, with more deaths from bleeding in the REBOA+SC group (32%) compared to the SCA group (17%). These findings suggest that the prolonged times observed may reflect the specific healthcare system’s resources, and further investigation into pre-hospital REBOA deployment could address these delays and improve outcomes.

REBOA Placement:
Unlike medication trials, this study focuses on a procedural intervention, highlighting the importance of clinician proficiency and experience. The trial’s median time from ED arrival to balloon inflation was 32 minutes, with a 17% failure rate in arterial cannulation, indicating deployment challenges. The training protocol was condensed and varied across sites, potentially impacting performance. A sensitivity analysis excluded initial REBOA attempts, but patient recruitment varied widely among centers, with one site conducting only one REBOA attempt every six months. This infrequency may contrast with larger trauma centers where more frequent use could enhance clinician skill.
Clinical Bottom Line:
The UK-REBOA Trial reveals that REBOA combined with standard care did not reduce 90-day mortality rates compared to standard care alone; instead, it showed a higher probability of increased mortality in the REBOA group. Methodological challenges, such as extended prehospital transport times, limited operator experience, and small sample size, introduce uncertainty to these findings. While REBOA may not be a universal solution, further research is needed to determine specifically which patients or injury patterns would benefit from its deployment.

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