REBOA

by Lissiana J

Resuscitative Endovascular Occlusion of the Aorta is a new minimally invasive procedure designed to control non-compressible haemorrhages. One of the most common preventable causes of death in trauma is bleeding out so this procedure provides the potential to reduce this problem. Essentially, a balloon catheter is inserted to the desired aortic zone via the femoral artery and the balloon inflates which temporarily occludes blood flow to the wound. However, like with any procedure, there are many possible complications that can arise. For example the insertion of the balloon may cause vascular injury ( which can be treated by endovascular techniques such as stents) but it also causes limb ischemia as there is limited blood supply to the legs or the balloon may even rupture. But compared to open aortic cross clamping which is the current common practice to control haemorrhages, the rate of complications is much lower.

REBOA can be placed in Zone 1 of the Aorta which is the descending aorta or in Zone 3, right above the aortic bifurcation. Zone 2 is always avoided in order to preserve the gastrointestinal perfusion. This is because gastrointestinal hypoperfusion is considered to be the cause of intestinal necrosis and can trigger multiorgan failure associated with hemorrhagic shock. 

In theory this procedure has the potential to work really well and so it was tested in a clinical trial. In 2023, hospitals in the UK took part in a random clinical trial to truly test the effects of REBOA against standard care alone; in the trial standard care was defined as operative procedures, endovascular haemorrhage control and intubation. Because exsanguinating haemorrhage is so rare in the UK, a Bayesian design for the clinical trial was implemented which allows a relatively small number of patients to be enrolled in the study whilst still producing meaningful evidence regarding REBOA. The trial was planned for the participation of 120 patients, however it was stopped early so only 90 patients took part- 46 patients received REBOA and standard care and 44 patients received standard care alone. It is important to note that 97% of patients had experienced blunt traumas and that all patients were tachycardic but the REBOA group more so. In the REBOA group, only 19 patients actually had balloon inflation, with 8 patients experiencing unsuccessful arterial access. Additionally, the median time from arrival to balloon inflation was 32 minutes which is 32 minutes where the patient is bleeding out. 

The outcome of this clinical trial is that REBOA with standard care increased mortality compared to standard care alone which is not the result that was hypothesised. Despite the results, this trial actually experienced a lot of problems which perhaps affected the end result. For instance, the patient transit time was a median of 90 minutes so if the patients had better access to the REBOA, the outcome would have been different. Additionally, the fact that this procedure required specialist training may have created a negative effect on the results. It is important to note that this trial cannot be compared with the common placebo clinical trial. The doctors are not carrying out the same exact procedure and only changing the type of drug for each patient, instead they are having to do a whole different process for each case. They have to customise the procedure for each patient and multiple steps and skills are required for it to be successful. Even though the doctors had practised this procedure countless times with stimulators, we must keep in mind that trying to successfully access the femoral artery of a dying patient bleeding out in front of them must be very difficult and may affect the application process. Also, due to the nature of the study, the small sample size may have caused an overestimation of potential harm which may not follow through when carried out in larger groups.

Overall, although the concept of REBOA is revolutionary in theory, when performed in practice the results did not demonstrate a reduction in mortality. However, it is important to consider if any of the uncontrollable variables had any impact on the end result and if there is a subset of trauma patients where REBOA could be extremely beneficial.