REBOA is an endovascular approach to aortic occlusion that aims to prevent cardiac arrest in cases of severe haemorrhagic shock. It is less invasive than RTACC, which may be used for the same purpose, and it can be used in interventions that require precision, including partial or intermittent occlusion. However, REBOA may be more time-consuming than RTACC. These aspects of both procedures need to be considered to identify the approach that is most likely to yield desirable patient outcomes.
Previously, Inoue et al. performed a propensity score-based analysis of the Japan Trauma Data Bank to evaluate mortality rates associated with REBOA, [8] which were found to be higher than those associated with non-REBOA interventions. The median time required from hospital arrival to intervention in the REBOA group was 97 minutes. This finding suggests that the use of REBOA in situations where it is not indicated and the lack of systems that enable to rapidly perform definitive haemostasis may have worsened the outcomes of patients undergoing REBOA. These patterns may reflect the specific Japanese context, which lacks standardised protocols for the use REBOA across trauma centres.
The 31st Annual Meeting of the Japanese Association for the Surgery of Trauma in 2018 resulted in two sets of guidelines on the adaptation and utilisation of IABO/REBOA for trauma care. The first one states that IABO/REBOA should not be implemented for the sole purpose of obtaining a computed tomography scan, but to shorten the time to controlled bleeding. The second one states that the aim of employing IABO/REBOA is to prevent cardiac arrest.8 Matsumoto et al. reported that RTACC is more frequently performed in patients with thoracic trauma than in those without thoracic trauma in Japan.9 Matsumura et al. performed a study based on a Japanese multi-institutional dataset, showing that partial occlusion, conversion from thoracotomy, and timely but shorter occlusion might be related to successful hemodynamic stabilisation and improved survival.10 Early recognition of patients who may require REBOA following early arterial access may help improve outcomes.11
This study showed that the time to intervention and total occlusion time were correlated with 24-hour survival rates in the shock group, suggesting that prolonged shock and coagulopathy due to delayed haemostatic intervention and the progression of lower organ ischaemia due to a delay in deflation of REBOA may worsen outcomes. Factors associated with survival may include shortening the time to the start of haemostatic intervention and early deflating of REBOA, i.e., immediate definitive haemostasis.
Our previous study (n=14) showed that blood pressure increased significantly with REBOA use without affecting outcomes. Meanwhile, reduced transfusion volume and total occlusion time (i.e., immediate definitive hemostasis) were factors associated with survival.12 In addition, another study (n=46) suggested that REBOA may be effective in the treatment of shock, either combined with haemostatic intervention for hemodynamic stabilisation or by achieving temporary hemostasis, and that prior insertion of REBOA (prophylactic use) may be effective if the patient is not in shock at the time of admission (unpublished data). In a case reported in Japan, intraoperative bleeding was controlled and a good surgical field was secured by the combined use of REBOA with haemostatic laparotomy, resulting in improved rates of hemostasis completion and survival.13 Reports from abroad, in which proximal control with REBOA was useful before intraoperative retroperitoneal hematoma exploration, support these findings.14,15
In summary, for traumatic haemorrhagic shock, it is important to combine the use of REBOA with immediate haemostatic intervention to achieve hemostasis first; alternatively, REBOA may be performed followed by hemostasis, provided delays can be avoided. The time window is approximately <1 h, based on the present findings; delays of >1 h to obtain a computed tomography scan or due to REBOA-associated factors may be detrimental to outcomes.
In the CPA group, the severity of injury and mortality rates were high; however, in some cases, the use of RTACC (conversion to REBOA) was effective. Conversion to REBOA helps reduce lower organ ischaemia, prevent hypothermia, and reduce chest wall bleeding (associated with thoracotomy) by shifting from complete occlusion by RTACC to partial or intermittent occlusion by REBOA, while ensuring the rapidity and certainty of RTACC. The REBOA handbook, the first official textbook in Japan, reports the usefulness of REBOA.16 In addition, the position of the catheter tip can be confirmed visually and by palpation under thoracotomy. A combination of interventions may expand the range of protocols available and improve patient outcomes. RTACC should be performed promptly for cases of impending cardiac arrest, and early conversion to REBOA may improve outcomes in some cases. The combined and conversion approaches are consistent with the original purpose of REBOA (resuscitative use by physiological indication).
In contrast, prophylactic REBOA use was helpful in some cases in the non-shock group. Prophylactic use may help achieve rapid definitive hemostasis by stabilising hemodynamic and maintaining a good field of view by controlling bleeding. Previous case reports from Japan have shown the benefits of prophylactic use in patients at high risk of major bleeding due to intraoperative manipulation,17,18 and those of intraoperative placement for patients with more stable admission physiology.19 Such a “non-resuscitative use” may seem paradoxical, given the name of REBOA, but it may lead to good outcomes.
Overall, REBOA may be used in different ways, some of which may help improve outcomes, provided great care is executed and the intervention is delivered at the right time. REBOA has been nicknamed the ‘countdown to death’, referring to the risks associated with lower organ ischaemia that increase while temporary hemodynamic stabilisation is achieved; consequently, this approach should be used judiciously. RTACC for the same purpose can be used differently or in combination with REBOA, as required; however, the timing of intervention remains paramount to outcomes.
This study, however, is subject to a limitation owing to its small sample size because it is a single-centre study and the use of REBOA is generally limited to severe cases including CPA. Although it is difficult to conduct prospective studies on REBOA, it is desirable to collect data and provide evidence through multicentre studies in Japan.