Low-impact scenarios may account for two-thirds of blunt traumatic aortic rupture

Traumatic aortic injury presenting to an adult major trauma centre

Introduction

Traumatic aortic injury is an uncommon condition. Timely diagnosis may enable early haemostatic resuscitation, essential to prevent worsening of the injury prior to definitive management. The aim of this study was to assess the utility of initial vital signs and presenting clinical characteristics to confirm or rule out aortic injury.

Methods

A retrospective review of patients from The Alfred Trauma Registry was conducted. Patients presenting between January 2006 and July 2014 and diagnosed with aortic injury were identified. Demographics and presenting clinical characteristics were extracted. Sensitivity of individual clinical variables for the detection of aortic injury was calculated.

Results

There were 77 patients identified with aortic injury, with an in-hospital mortality rate of 19.5% (95% CI: 10.6–28.3%). Of these, 68 (88.3%) patients presented after high-energy blunt mechanisms. Clinical signs and early chest X-ray findings were poorly sensitive to detect aortic injury. Patients who presented with hypotension had a greater severity of aortic injury, more commonly had associated abnormal investigation findings and were more likely to require blood products and inotropic agents (p < 0.05). However, sensitivity of initial hypotension to rule out aortic injury was 39.0% (95% CI: 28.1–49.9%).

Conclusions

The diagnosis of aortic injury was uncommon in hospital. Most injuries were secondary to high-velocity road traffic crashes or high falls. Clinical signs were not adequately sensitive to be used for the exclusion of aortic injury. We recommend a high degree of clinical suspicion and liberal imaging among cases where aortic injury is possible.

Defining acute aortic syndrome after trauma: Are Abbreviated Injury Scale codes a useful surrogate descriptor?

BACKGROUND

The severity and location of injuries resulting from vehicular collisions are normally recorded in Abbreviated Injury Scale (AIS) code; we propose a system to link AIS code to a description of acute aortic syndrome (AAS), thus allowing the hypothesis that aortic injury is progressive with collision kinematics to be tested.

METHODS

Standard AIS codes were matched with a clinical description of AAS. A total of 199 collisions that resulted in aortic injury were extracted from a national automotive collision database and the outcomes mapped onto AAS descriptions. The severity of aortic injury (AIS severity score) and stage of AAS progression were compared with collision kinematics and occupant demographics. Post hoc power analyses were used to estimate maximum effect size.

RESULTS

The general demographic distribution of the sample represented that of the UK population in regard to sex and age. No significant relationship was observed between estimated test speed, collision direction, occupant location or seat belt use and clinical progression of aortic injury (once initiated). Power analysis confirmed that a suitable sample size was used to observe a medium effect in most of the cases. Similarly, no association was observed between injury severity and collision kinematics.

CONCLUSION

There is sufficient information on AIS severity and location codes to map onto the clinical AAS spectrum. It was not possible, with this data set, to consider the influence of collision kinematics on aortic injury initiation. However, it was demonstrated that after initiation, further progression along the AAS pathway was not influenced by collision kinematics. This might be because the injury is not progressive, because the vehicle kinematics studied do not fully represent the kinematics of the occupants, or because an unknown factor, such as stage of cardiac cycle, dominates.

LEVEL OF EVIDENCE

Epidemiologic/prognostic study, level IV.