Screening for Blunt Thoracic Aortic Injuries: Are Chest X-Rays Adequate?

Document Type

Presentation

Publication Date

4-8-2006

Abstract

Objective: Thoracic aortic injuries following blunt trauma mechanisms are associated with high mortality rates. For survivors, chest X-rays (CXR) have traditionally been used as the screening modality to decide on the need for further diagnostic testing. The liberal use of spiral chest CT angiography (CTA) following all high-speed crashes regardless of CXR findings has been advocated. We set to determine the adequacy of utilizing CXR alone as a screening tool for blunt thoracic aortic injury (BTAI) at a Level I Trauma Center.

Methods: All patients with BTAI diagnosed clinically or at autopsy admitted to a Level I Trauma Center between Jan 1998 and Dec 2004 were identified. The CXRs of these patients and those of a cohort of blunt trauma patients with an ISS > 15 (control group) in the same time period were retrospectively reviewed by 4 trauma surgeons who were blinded to the diagnosis. Each of the trauma surgeons decided, based on each film viewed, if they would have proceeded to chest CTA, conventional aortic angiography or required no further studies to rule out BTAI.

Results: In the 7-year period, there were 83 patients with BTAI. CXRs were available for 47 patients, all motor vehicle crash victims. The CXRs of these patients and those of 49 controls were reviewed. Of the 47 patients with BTAI, the surgeons chose to proceed to chest CTA in 38 patients (81%), conventional aortography in 2 patients (4%) and no further testing in 7 patients (15%). A widened mediastinum was the most common CXR feature chosen to decide the need for further studies - 34/47 (72%). Loss of AP window (38%), indistinct aortic knob (28%) and pleural capping (4%) were other reasons. Patients with BTAI were more likely to have a positive CXR (40/47) when compared with the controls (25/49), statistically significant by chi-square testing (p<0.001). CXR sensitivity and specificity were 85.1% and 51%, respectively.

Conclusions: CXR is sensitive as a sole screening test for BTAI, but failed to identify up to 15% of patients with BTAI. Liberal use of chest CTA, especially following high-speed motor vehicle crashes, is highly recommended to minimize the incidence of missed thoracic aortic injuries. A widened mediastinum was the most frequent criterion used to indicate a positive CXR.

Comments

This paper was presented at the 16th Annual Scientific Meeting of the Society of Black Academic Surgeons, Cincinnati, OH.

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