[Successful recanalization of intracranial internal carotid artery occlusion by rapidly changing from the Penumbra System® to the Merci® Retrieval System to retrieve a predicted white thrombus: a case report].

This report describes a case of successful recanalization of intracranial internal carotid artery occlusion by rapidly changing from the Penumbra System® to the Merci® Retrieval System for the retrieval of a predicted white thrombus. A 72-year-old man was consulted to our department with a consciousness disturbance. The patient had undergone graft placement for the management of a thoracic aortic aneurysm 14 days prior. Neurological examination revealed left-sided severe motor weakness and dysarthria. Magnetic resonance(MR)imaging showed a cerebral infarction in the territory of the right internal carotid artery(ICA), while MR angiography revealed occlusion of the right ICA. The systemic intravenous injection of recombinant tissue plasminogen activator was contraindicated, so a mechanical thrombectomy was performed. The use of the Penumbra System® failed to achieve recanalization of the right ICA;therefore, revascularization using the Merci® Retrieval System was performed. As a result, complete recanalization was achieved approximately 2 hours and 45 minutes after symptom onset. The retrieved specimen was elastic and hard, and histological examination revealed a white thrombus without endovascular organization. Postoperatively, the patient was restless for 1 day but did not show any neurological abnormalities. His postoperative course was uneventful, and he was discharged 7 days later without any neurological deficits.