Extensive Mobile Thrombus of the Internal Carotid Discovered After Intravenous Thrombolysis: What Do I Do Now?

Abstract

This case report describes a rare presentation of ischemic stroke secondary to an extensive internal carotid artery thrombus, subsequent therapeutic dilemma, and clinical management. A 58-year-old man was administered intravenous (IV) thrombolysis for right middle cerebral artery territory ischemic stroke symptoms. A computed tomography angiogram of the head and neck following thrombolysis showed a longitudinally extensive internal carotid artery thrombus originating at the region of high-grade calcific stenosis. Mechanical embolectomy was deferred because of risk of clot dislodgement and mild neurological symptoms. Recumbency and hemodynamic augmentation were used acutely to support cerebral perfusion. Anticoagulation was started 24 hours after thrombolysis. Carotid endarterectomy was completed successfully within 1 week of presentation. Clinical outcome was satisfactory with discharge modified Rankin Scale score 0. A longitudinally extensive carotid artery thrombus poses a risk of dislodgement and hemispheric stroke. Optimal management in these cases is not known with certainty. In our case, IV thrombolysis, hemodynamic augmentation, delayed anticoagulation, and carotid endarterectomy resulted in a favorable clinical outcome.

Keywords: carotid artery thrombosis; cerebrovascular disorders; stroke.

Figure 1.

Computed tomography angiography. A high-grade calcific stenosis was present in the right internal carotid artery just distal to the bifurcation on axial sequencing (blue arrow, A). Emanating from the stenosis was an intraluminal thrombus (blue arrow, B). The intraluminal clot was longitudinally extensive as seen on sagittal views (blue arrows, C) and terminated at the petrous junction (blue arrow, D).

Figure 2.

Magnetic resonance imaging. Three representative diffusion-weighted slices completed within hours of symptom onset show hyperintense acute infarctions with embolic appearance in the distribution of the right middle cerebral artery (A, arrows). Repeat diffusion-weighted imaging completed at 48 hours shows development of interval ischemic infarctions consistent with continued embolization (arrows, B). Magnetic resonance imaging with 2-dimensional time-of-flight sequencing completed at 48 hours shows focal carotid stenosis (arrow) and the intraluminal clot is not seen (C).