Blunt Aortic Injury

Blunt Aortic Injury from Sun YaiCheng

Blunt Aortic Injury
N Engl J Med  2008;359:1708-16.

Pathophysiology

• Sudden increase in intra-abdominal pressure may explain the association between blunt aortic injury and diaphragmatic rupture.
• "Water-hammer" effect: simultaneous occlusion of the aorta and a sudden elevation in blood pressure
• "Osseous pinch" effect: entrapment of the aorta between the anterior chest wall and the vertebral column.

Diagnosis

• The absence of the following signs on CXR were valuable to exclude the diagnosis of aortic injury:

• loss of the aortico-pulmonary window
• abnormality of the aortic arch
• rightward tracheal shift
• widening of the left para-spinal line without associated fracture

• Between 7.3% and 44% of patients with blunt aortic injury may have a normal mediastinum on CXR.

• Helical CT of the thorax is now the diagnostic test of choice (sensitivity 100%).

• Minimal Aortic Injury was defined as an intimalflap of less than 1 cm with no or minimal peri-aortic hematoma, 50% of minimal aortic injuries that were followed up had developed pseudo-aneurysms by 8 weeks after injury.

• If the injury is associated with significant thrombus, peri-aortic hematoma, lumen encroachment, or pseudo-aneurysm, it is our practice to proceed with endograft coverage.

Surgical Repair

• Advantages of the veno-arterial bypass include the ability to cool the patient, which potentially enhances spinal-cord protection.

Endovascular Repair

Advantages

• No physiological burden
• In brain injury, the device can be deployed with the head of the bed elevated
• Not require single-lung ventilation
• Minimal or no heparin
• No need for a bypass of any kind
• No cause of paraplegia

Technical Limitations to Endografting

• Injuries that occur adjacent to a sharp bend in the aorta may result in poor apposition of the covered stent to the aortic wall.
• Lesions adjacent to the left subclavian artery.
• Coverage of the left subclavian artery can result in ischemia of the upper extremity or territory perfused by the left vertebral artery.