Blunt Cardiovascular Injury— TEE vs. CT

Abstract & Commentary

Source: Vignon P, et al. Comparison of multiplane transesophageal echocardiography and contrast-enhanced helical CT in the diagnosis of blunt traumatic cardiovascular injuries. Anesthesiology 2001;94:615-622.

The authors prospectively compared the accuracy of transesophageal echocardiography (TEE) and helical computed tomography (CT) in 110 consecutive patients with severe blunt chest trauma (ISS 34 ± 14). High-risk patients were defined by the presence of at least one of the following: 1) history of deceleration; 2) ejection or associated fatality; 3) pedestrian struck by vehicle; 4) external signs of major chest injury; 5) chest trauma requiring mechanical ventilation; 6) unexplained shock; or 7) wide mediastinum on chest x-ray. Studies were obtained in random order and results were interpreted independently. Standard definitions of aortic and cardiac injury were employed.

Seventeen patients (15.5%) had vascular injury, and 11 (10%) had cardiac injury. TEE and CT identified all aortic injuries necessitating surgical repair. One innominate artery injury missed by TEE was detected by CT. TEE detected four intimal lesions missed by CT; these all were managed non-operatively. Cardiac lesions were diagnosed in all but two cases by TEE alone. TEE performed as follows: sensitivity, 93%; negative predictive value, 99%; specificity, 100%; positive predictive value, 100%. CT performance, in contrast, was as follows: sensitivity, 73%; negative predictive value, 95%; specificity, 100%; positive predictive value, 100%.

Comment by Michael A. Gibbs, MD, FACEP

During the last three years, several authors have documented the high accuracy of helical CT in diagnosing blunt aortic injury.1-3 This is the first study to compare CT to TEE prospectively. In this study, TEE had a greater sensitivity for detecting aortic injury, although the clinical significance of the small intimal lesions missed by CT is unclear. CT imaging detected all aortic injuries requiring surgery. The single-arch vessel injury was missed by TEE and picked up by CT. These injuries are notoriously difficult to detect and some authors believe that formal angiography is the only method that reliably excludes them.

The ability of TEE to pick up associated cardiac lesions and myocardial dysfunction is a significant advantage of the technology. TEE should be considered when this is suspected clinically. A major benefit of TEE is the ability to perform the test in the unstable patient (e.g., in the emergency department, intensive care unit, or operating room). Finally, TEE is very operator-dependent. The investigators in this study had significant experience; this does not generalize to every hospital. Each test has important advantages and limitations. Good clinical judgment and sound management protocols will help us choose which is the right test, and the two often may be complementary.

References

1. Dyer DS, et al. Thoracic aortic injury: How predictive is mechanism and is chest computed tomography a reliable screening tool? A prospective study of 1,561 patients. J Trauma 2000;48: 673-682.

2. Fabian TC, et al. Prospective study of blunt aortic injury: Helical CT is diagnostic and antihypertensive therapy reduces rupture. Ann Surg 1998;227:666-676.

3. Mirvis SE, et al. Use of spiral computed tomography for the assessment of blunt trauma patients with potential aortic injury. J Trauma 1998;45:922-930.