Distal aortic arch aneurysm after endovascular stent graft repair for type B chronic aortic dissection

The innominate artery is the second most common site of blunt injury to the aortic vessels, and blunt trauma is responsible for 35% of innominate artery injuries. Still, fewer than 100 cases of innominate artery injury caused by blunt trauma have been documented. An interesting association has been reported between this type of injury and bovine arch anatomy, in which the left common carotid originates from the innominate artery. Although there is only an 11% normal incidence of bovine arch anatomy, 29% of patients who have innominate artery disruption exhibit this anomaly, suggesting a predisposition to sustaining blunt injury at the innominate artery. One study recommended bypass of the injured segments of the arch before exploring the hematoma. This patient was placed on cardiopulmonary bypass before dissection of the hematoma. Cardiopulmonary bypass allows for greater visualization of the arch by decompressing the heart and provides more hemodynamic control. The risk of systemic anticoagulation in the setting of a grade III liver laceration and femur fracture did not escape us, and measures were taken to reduce the patient’s risk by placement of an external fixator on the femur and by aggressive surveillance to detect early intraperitoneal bleeding. Because repair of this injury would likely disrupt most of the cerebral blood flow, the issue of cerebral perfusion had to be addressed. In this particular patient, retrograde cerebral perfusion was used in conjunction with deep hypothermia and circulatory arrest. Our center has had extensive experience with this technique in repair of complex arch reconstructions and acute type A dissections. Despite recent reports suggesting that retrograde cerebral perfusion may be linked to postoperative neurologic dysfunction, our experience is that the incidence of perioperative stroke is reduced. In addition, retrograde cerebral perfusion also extends greater latitude in operating time and cools the brain down roughly an additional 10°C. Finally, it provides a deairing capacity by continually bathing the cerebral vascular system in blood.