Study reveals classification scheme for treatment of blunt aortic injury

New research at the University of Washington's (UW) Harborview Medical Center in Seattle reveals a classification scheme for the treatment of blunt aortic injury (BAI). The authors used the radiographic and clinical data of 140 patients with BAI in an effort to provide clear treatment guidelines. The study has been published in the December 2011 issue of the Journal of Vascular Surgery®, the official publication of the Society for Vascular Surgery®.

Patient data was collected from 1999 to 2008 and studied retrospectively. Patients with a radiographically or operatively confirmed diagnosis of BAI by echocardiogram, computed tomography or angiography were included.

"Most of the injuries were pseudoaneurysms at the isthmus (70 percent)," said Benjamin W. Starnes, MD, Professor of Surgery and Chief of the vascular surgery division at UW. "Our classification system was based on the presence or absence of an aortic external contour abnormality, defined as an alteration in the symmetric round shape of the aorta." Injury characteristics were as follows:

• an intimal tear (IT) - absence of an aortic external contour abnormality and intimal defect and/or thrombus of less than 10 mm in length or width (16.4 percent)
• a large intimal flap (LIF) - the absence of aortic external contour abnormality and intimal defect and/or thrombus of more than 10 mm in length or width (5.7 percent)
• a pseudoaneurysm - the presence of aortic external contour abnormality and contained rupture (71 percent)
• a rupture with the presence of aortic external contour abnormality and free contrast extravasation or hemothorax at thoracotomy (6.4 percent).

Researchers also reported survival rates by classification were IT, 87 percent; LIF, 100 percent; pseudoaneurysm, 76 percent; and rupture, 11 percent (1 patient). Of the IT's, LIF's, and pseudoaneurysms treated nonoperatively, none worsened, and 65 percent completely healed. No patient with an IT or LIF died. Most patients with ruptures lost vital signs before presentation or in the emergency department and did not survive. Hypotension before or at hospital presentation and size of the peri-aortic hematoma at the level of the aortic arch predicted the likelihood of death from BAI.

"Our classification scheme showed that no patient with a normal external contour of the aorta died of the BAI and ITs can be managed non-operatively," said Dr. Starnes. "Patients with ruptures will die, and resources may be prioritized elsewhere. Patients with LIFs do well; most are treated with a stent graft."

Dr. Starnes added that if a pseudoaneurysm is going to rupture, it does so early, before or in the operating room, and at UW current practice is to treat all pseudoaneurysms with endovascular repair if the patient has a reasonable likelihood of survival. Hematoma at the arch on CT scan and hypotension before or at ED arrival also will help to predict which pseudoaneurysms need urgent instead of semi-elective repair. Researchers concluded that longer-term follow-up of these BAI patients is needed to determine the durability of an "endovascular (EVAR) first" strategy. The following recommended University of Washington clinical treatment guidelines for the management of BAI are:

1. All patients with radiographic evidence of BAI should undergo anti-impulse therapy with β-blockade, if tolerated, coupled with antiplatelet therapy (81 mg aspirin).

2. Observation alone with interval follow-up computed tomography angiography within 30 days is appropriate for all IT's less than 10 mm.

3. Selective management of LIF's less than 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.

4. All patients with an aortic external contour abnormality should be considered for semi-elective (1 week or less) EVAR 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 aortic arch hematoma of more than 15 mm should be repaired with EVAR methods on a more urgent basis.

5. Intentional left subclavian artery coverage without revascularization is well tolerated in a majority of patients with BAI.

6. Patients with traumatic brain injury and an aortic external contour abnormality should be considered for earlier repair if a deliberate increase in mean arterial pressure is deemed beneficial for the patient.

Source: Journal of Vascular Surgery