Contemporary analysis of thoracic aortic injury: importance of screening based on crash characteristics.

Background: To use motor vehicle crash (MVC) characteristics to determine risk of thoracic aortic injury (TAI) and provide updated mortality data.
Methods: Vehicle crash variables and patient medical data from 64,245 MVC occupants (1988-2002) were obtained from the National Automotive Sampling System. Descriptive and logistic regression analyses were used to determine the relationship of crash and occupant characteristics to TAI.
Results: Seven hundred ninety occupants (1.2%) had TAI. Overall mortality with TAI was 92%. Prehospital mortality was 63%. Patients taken to a trauma center had significantly lower mortality (75%) than did patients taken to a non-trauma center (90%) (p = 0.006). Risk of TAI was highest with a near-side crash impact. Risk of TAI increased with increasing change in velocity and increasing mass of the striking vehicle. Seat belts were protective not only for all occupants in frontal crashes, but also for drivers and front passengers in a near side lateral impact, whereas airbags were protective only in frontal crashes. No specific injuries reliably predicted TAI with sufficient sensitivity and specificity to be clinically useful.
Conclusions: TAI remains a highly lethal injury. Prehospital mortality in this series is lower than in most previous reports, and survival is higher at trauma centers versus non-trauma centers. Associated injuries are poor predictors of TAI. Screening for TAI should include increased emphasis on crash and vehicle occupant characteristics, especially high-velocity MVC, near-side impact, and lack of seat belt use.