Repeated thrombus formation immediately following carotid endarterectomy

A 56-year-old male presented with thrombus formation manifesting as cerebral embolic infarction suspected to be caused by hemostasis at the carotid bifurcation, not by the intimal abnormalities or hematological disorders. Thrombus repeatedly and reproducibly appeared at the same area in spite of carotid endarterectomy (CEA). Ultrasonography demonstrated a stenotic lesion of the cervical carotid bifurcation. Medical treatment reduced the stenosis, but the thrombus was repeatedly formed at the same area of the cervical carotid bifurcation. CEA was performed. Histological examination of the specimen found only the underlying thin intima consisting of mild fibrous atheromatic change without ulceration or vascular dissection. Ultrasonography following CEA showed reduced blood flow, indicating hemostasis, and moyamoya appearance in that area. The thrombus had recurred in spite of the medical treatment with anti-platelet agent. This repeated thrombus was gradually dissolved and reduced with anticoagulant therapy. Thrombus causing cerebral embolic stroke and originating at the cervical carotid bifurcation is usually due to the intimal atherosclerotic change such as ulcer formation or vascular dissection. The thrombus in this case was probably formed by hemostasis at the cervical carotid bifurcation and CEA was not effective to prevent recurrence.