Aortic Rupture, Traumatic (Tai)

Basics

Traumatic aortic rupture (also referred to as traumatic aortic injury or TAI) is the cause of death in an estimated 20% of lethal motor vehicle collisions
An estimated 85% of patients with TAI die before reaching the hospital
Patients surviving to the ED usually have a contained rupture as aortic blood is tamponaded by the adventitia
Without proper treatment, of the 15% that survive the initial event, 49% will die within the first 24 hr, and 90% within 4 mo
Mean age of patients sustaining aortic rupture is 33 yr, and 70% are male
Most tears are transverse, not longitudinal
Tears may be partially or completely circumferential

Most commonly results from motor vehicle collisions >30 mph
Unrestrained passengers, driver seat occupants (injuries from steering column and instruments), and ejected occupants
Other mechanisms: Auto vs. pedestrian, airplane crashes, falls from height >10 ft, crush and blast injuries, direct blow to chest
Proposed mechanisms of aortic injury:
- Shear forces arising from unequal rates of deceleration of the relatively fixed descending aorta and the more mobile arch
- “Bending” stress at the aortic isthmus may cause flexion of the aortic arch on the left mainstem bronchus and pulmonary artery
- Twisting of the arch forces it superiorly and causes it to stretch
- Osseous structures (e.g., medial clavicles, manubrium, first rib) cause pinching of the trapped aorta as they strike the vertebral column
- “Water hammer” fluid wave causes explosive rupture of aorta just distal to the aortic valve

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