Amaurosis fugax associated with congenital vascular defect.

A 68-year-old female with no significant past medical history presented with loss of vision in the lower half of her left eye that lasted <5 minutes. No abnormalities were found on ocular or physical exam. Computed tomography angiography and carotid ultrasound were performed, which confirmed the diagnosis as amaurosis fugax with two abnormalities leading to the transient retinal vessel occlusion. First, it was found that the patient has a congenital vascular anomaly, which consisted most notably of a right-sided aortic arch. This vascular anomaly also consisted of abnormal branching of the left subclavian and common carotid arteries, predisposing the patient to turbulent blood flow and increased risk of the formation of an atherosclerotic plaque at the origin of the common carotid artery. This is an abnormal location for a plaque leading to amaurosis fugax compared to the most common location at the carotid bifurcation. Endarterectomy was not performed because of the difficult location of the plaque and tortuosity of the vessel. Rather, medical intervention with antiplatelet and lipid-lowering therapy was initiated to lower the risk of future retinal or cerebral thromboembolic events.