What is your approach for a patient with an acute ischemic stroke caused by an aortic thrombus?

It depends upon the risks, factors, and age of the patients. If they have hypercoagulable states then the patient needs anticoagulation otherwise, aortic atheroma is generally "white" clot which is made up of platelets and cholesterol and hence, treatment would be anti-platelets and cholesterol lowering medicine. If it had caused acute Intracranial occlusion, then obviously if the patient is in beyond 41/2 hours IV thrombolytic window then EVT by expert hands. There are not that many literatures available to specifically this situation.

Aortic thrombus or complex atheroma >4mm or hypermobile need anticoagulation and hypercoagulable work up.

If no hypercoagulable condition is identified then after 4-8 weeks reimage and, if resolved, de-escalate to antiplatelet.