CASE REPORT

In July 2010, a 17-year-old boy was airlifted to Harborview Medical Center in Seattle with traumatic transection of his thoracic aorta, often referred to as blunt aortic injury (BAI). The patient was cliff jumping with friends in Idaho from a 50-foot-tall ridge into still water below; he struck the water with his chest and complained of immediate, excruciating chest and back pain. His mother took him to a nearby hospital facility, where a computed tomography (CT) scan was performed (Figure 1). Upon presentation at Harborview, he was taken to the operating room and underwent thoracic endovascular repair with a device that is specifically designed to treat these types of injuries, the Conformable GORE® TAG® Device (Gore & Associates) (Figure 2). The surgery was performed as part of the Conformable GORE® TAG® Device Traumatic Transection Study (08-02) after his surgeons received approval for “emergency use” due to the fact that the patient was excluded from the study, as he was a minor.

Patients with BAI are typically young and have anatomic considerations that make conventional endovascular repair a challenge. Small and differential aortic diameters, steep “Gothic” arch configurations, and small-diameter access vessels are common in this patient population. Two-year follow-up CT scanning of this patient demonstrated a perfect result, with good apposition of the graft, no migration or in-folding, and more importantly, no adverse clinical events (Figure 3).

THE PROBLEM

During the past decade, there has been a shift toward endovascular repair of patients with BAIs. Multiple series with short- and mid-term follow-up suggest that thoracic endovascular aortic repair (TEVAR) is a viable alternative to open repair for traumatic aortic injuries. Several studies have demonstrated reduced mortality and paraplegia rates with endovascular repair of BAI compared with open repair.1 Recent clinical practice guidelines endorsed by the Society for Vascular Surgery suggest that endovascular repair of traumatic thoracic aortic injuries should be performed preferentially over open surgical repair or non-operative management.2 Paraplegia resulting from compromise to the collateral circulation of the spinal cord is reported in open repair of traumatic aortic disruptions but has been conspicuously absent in multiple meta-analyses in which TEVAR for blunt thoracic aortic injury (BTAI) has been studied.3 The only device that is currently approved by the US Food and Drug Administration to treat BAI is the Conformable GORE® TAG® Device, which was approved for this indication in January 2012.

Until recently, physicians were forced to use stent grafts that were originally designed to treat aneurysmal disease in the young patient population. Graft oversizing in small aortas can lead to device compression (Figure 4). Graft collapse can also occur due to a lack of apposition of the proximal stent graft along the inner curvature of the aortic arch. The recent release of the Conformable GORE® TAG® Device addresses the aortic size issue and allows for successful treatment of patients with aortic diameters as small as 16 mm.

THE SOLUTION

Repair is dictated by the type of injury, and the timing of repair depends on the patient's associated injuries. Intimal tears (< 10 mm) heal with non-operative management. The University of Washington clinical treatment guidelines for BAI are as follows:4

  • All patients with radiographic evidence of BAI should undergo anti-impulse therapy with beta-blockade, if tolerated, coupled with antiplatelet therapy (81 mg of aspirin).
  • Observation alone with interval follow-up CT angiography within 30 days is appropriate for all intimal tears < 10 mm.
  • Selective management of large intimal flaps (> 10 mm) is appropriate, with repeat imaging within 7 days to assess for progression. Evidence of progression should be managed, when possible, with endovascular repair.
  • All patients with an aortic external contour abnormality on CT angiography should be considered for semielective (< 1 week) endovascular repair if there is a high likelihood of survival from other associated injuries. These patients should be monitored with CT imaging as follows: 1 month, 6 months, 1 year, and every other year thereafter. Patients with hypotension on presentation and an aortic arch hematoma > 15 mm should be repaired with endovascular methods on a more urgent basis.
  • Intentional left subclavian artery coverage without revascularization is well tolerated in the majority of patients with BAI.
  • Patients with traumatic brain injuries and aortic external contour abnormalities should be considered for earlier repair if a deliberate increase in the mean arterial pressure is deemed to be beneficial for the patient.

The short- and medium-term results of TEVAR for BTAI are encouraging, but the impact of aortic growth on graft anatomy in the long-term is not known. It has been shown that the proximal thoracic aorta dilates minimally after endovascular repair of BTAI, with the segment just distal to the left subclavian artery expanding at a slightly greater rate.2 The trauma population tends to be young and is expected to live for decades following a successful repair. The concern for graft migration as aortic remodeling occurs with growth remains valid, and adherence to a long-term follow-up protocol is imperative.

CONCLUSION

Newer devices have definitely made a difference in the management options for BAI. Conformable devices with compression resistance offer a potentially permanent solution to this life-threatening situation.

Benjamin W. Starnes, MD, is a professor and Chief of the Vascular Surgery Division with the University of Washington in Seattle, Washington. He has disclosed that he has received research support from Gore & Associates, Bolton Medical, and Cook Medical. Dr. Starnes may be reached at starnes@uw.edu.

  1. Demetriades D, Velmahos GC, Scalea TM, et al. Operative repair or endovascular stent graft in blunt traumatic thoracic aortic injuries: results of an American Association for the Surgery of Trauma multicenter study. J Trauma. 2008;64:561-570.
  2. Lee WA, Matsumura JS, Mitchell RS, et al. Endovascular repair of traumatic thoracic aortic injury: clinical practice guidelines of the Society for Vascular Surgery. J Vasc Surg. 2011;53:187-192.
  3. Tang GL, Tehrani HY, Usman A, et al. Reduced mortality, paraplegia, and stroke with stent graft repair of blunt aortic transections: a modern meta-analysis. J Vasc Surg. 2008;47:671-675.
  4. Starnes BW, Lundgren RS, Gunn M, et al. A new classification scheme for treating blunt aortic injury. J Vasc Surg. 2012;55:47-54.