Fatal Aortic Rupture following Endovascular Aneurysm Repair in a Case with Traumatic Thoracic Aortic Injury

Case Presentation

A previously healthy 16-year-old boy was transferred to a children's tertiary trauma centre after a motor vehicle accident (MVA) in which he was a restrained passenger. On presentation he was unconscious, intubated, and haemodynamically unstable with a heart rate of 140 bpm and a systolic pressure of 85 mmHg. His initial haemoglobin was 100 g/L. The chest radiograph demonstrated a widened mediastinum with effacement of the aortic knuckle consistent with a significant mediastinal haematoma. A CT scan with IV contrast confirmed an aortic injury at the level of the isthmus, 1.5 cm distal to the origin of the left subclavian artery.

The patient was admitted to the paediatric intensive care unit and stabilised, with systolic pressures maintained below 100 mmHg. Following consultation with the vascular surgery team the decision was taken to manage the aortic injury with EVAR. The patient's aortic diameters were as follows: ascending aorta above the injury: 18.6 mm×18.6 mm; aorta below the injury: 18.7 mm×19.6 mm; length from the injury to the left subclavian origin: 1.5 cm. The patient was transferred to the local vascular centre where a Cook Zenith single endovascular stent graft (diameter: 26 mm, length: 77 mm, COOK Medical Inc, Bloomington, IN, USA) was inserted under general anaesthesia ([Fig. 1]). Due to the small size of the patient, a left common femoral arterial cutdown was required to gain adequate access. The procedure was otherwise uneventful with good proximal graft deployment just distal to the left subclavian artery margin. Angiographic imaging carried out post procedure confirmed satisfactory graft placement and complete coverage of the aortic defect. 4 days after the EVAR a repeat chest CT with contrast confirmed the good position of the graft with no evidence of contrast extravasation. The patient had also sustained hepatic and renal injuries as well as pulmonary contusions and minor musculoskeletal injuries; all were managed non-operatively. The patient was discharged home on post-admission day 18 in good condition, on a daily 81 mg dose of aspirin.

Fig. 1 Angiography at the time of EVAR demonstrating complete exclusion of the pseudoaneurysm and satisfactory graft placement.

The patient presented to a peripheral hospital 1 week later with shortness of breath and chest pain, elevated WBC, bilateral lower lobe consolidation and a left pleural effusion on chest radiograph. His presumed diagnosis was pneumonia and he was started on moxifloxacin. After 3 days on antibiotics with no improvement of symptoms, a CT scan of the chest was carried out, which demonstrated aneurysmal dilatation of the thoracic aorta immediately distal to the inferior margin of the stent ([Fig. 2]). The patient was haemodynamically stable at the time of the CT scan and was transferred immediately to the regional vascular centre 1 h away where the graft had originally been inserted. On arrival the patient had sinus tachycardia of 128 bpm and was mildly hypotensive with a systolic blood pressure of 98 mmHg and haemoglobin of 98 g/L. Repair was planned for the following morning using a graft extension to cover the aneurysm; the delay was to allow for correction of the patient's unexplained coagulopathy (INR 2.1). However, within 5 h of admission, the patient became acutely unstable and died, despite all efforts at resuscitation including emergent thoracotomy and open cardiac massage. Intraoperatively a tear involving 60% of the aorta was identified just millimetres distal to the intact graft.

Fig. 2 CT at representation with a large pseudoaneurysm at the bottom end of the graft.

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