Yes, a thrombus at the aortic arch origin of the left common carotid artery can absolutely embolize and cause vertebral artery territory infarcts.
A thrombus located in the aortic arch at the left carotid origin represents a high-risk embolic source that can shower emboli both antegrade into the carotid circulation and into adjacent arch vessels, including the vertebral arteries, particularly if the left vertebral artery has an aberrant origin directly from the aortic arch (present in 6% of adults) 1.
Anatomic Basis for Vertebral Territory Embolization
The key anatomic considerations are:
Standard anatomy: The left vertebral artery typically arises from the left subclavian artery, which originates from the aortic arch just distal to the left common carotid artery. A thrombus at the left carotid origin sits in close proximity to the subclavian/vertebral origin and can easily embolize into this territory 1.
Aberrant anatomy: In 6% of adults, the left vertebral artery arises directly from the aortic arch between the left carotid and left subclavian arteries 1. In this variant, the vertebral artery origin is immediately adjacent to or even overlapping with the left carotid origin, making vertebral territory embolization highly likely from a thrombus in this location.
Flow dynamics: Mobile thrombi in the aortic arch are exposed to high-velocity turbulent flow that can fragment and propel emboli into any of the arch branch vessels, not just the vessel at the thrombus origin 2, 3.
Clinical Evidence
Recent case reports confirm this mechanism:
Direct visualization: Angioscopy performed immediately after cerebral thrombectomy identified aortic arch thrombus near the left carotid origin as the embolic source, establishing the causal relationship 3.
Mobile thrombi: Floating aortic arch thrombi involving the left common carotid artery have been documented causing both carotid and other territory strokes, demonstrating the capacity for multi-territorial embolization 4, 5.
High recurrence risk: Aortic arch atheroma with mobile thrombi carries a particularly high risk of recurrent embolic events across multiple vascular territories 2, 6.
Clinical Implications
Immediate anticoagulation is indicated when mobile aortic arch thrombi are identified, as this has been shown to achieve complete thrombus resolution in 80% of cases and prevent recurrent embolization 2.
Key diagnostic points:
- Transesophageal echocardiography through the suprasternal window is highly effective for detecting and monitoring aortic arch thrombi 2.
- CT angiography provides confirmatory imaging and better visualization of arch anatomy 2, 5.
- Consider aberrant vertebral artery anatomy when evaluating embolic stroke patterns, as this increases vulnerability to vertebrobasilar embolization from arch sources 1.
Critical pitfall: Combining anticoagulation with antiplatelet therapy in this setting significantly increases hemorrhagic complications and should be avoided 2. Once the mobile thrombus resolves on follow-up imaging, anticoagulation can be discontinued if no other indication exists 2.
The location you describe—aortic arch at the left carotid origin—is a well-established embolic source for both anterior (carotid) and posterior (vertebrobasilar) circulation strokes 3, 6, 7.