[Case of internal carotid artery stenosis complicated with filter obstruction during carotid artery stenting with an embolus protection filter].

The SAPPHIRE trial has established carotid artery stenting (CAS) in high-surgical-risk patients as an effective alternative to carotid endarterectomy. Since the occurrence of distal embolization with CAS is still a major concern, an embolus protection device is usually employed during the procedure. Although the advantage of the filter device is continuation of blood flow during the procedure, blood flow is occasionally reduced due to plaque debris or thrombus. Here, we report a case of internal carotid artery (ICA) stenosis complicated with filter obstruction during CAS. A 74-year-old woman who had a history of coronary artery stenting was referred to our hospital for the treatment of carotid artery stenosis. Angiography showed occlusion of the right ICA and high-grade stenosis at the origin of the left ICA. Since cerebral circulation was impaired significantly in the left cerebral hemisphere, CAS was performed for the left ICA stenosis using an embolus protection filter. Self-expandable stent was placed into the left ICA following predilation. The patient developed consciousness disturbance and right hemiparesis during postdilation. Angiography showed impairment of blood flow, indicating filter obstruction. The debris containing blood stasis was removed with an aspiration catheter and the flow was restarted retrieving the filter. The symptom recovered within one hour. Appropriate antithrombotic therapy and preparation for filter obstruction such as the provision of an aspiration catheter are important in CAS using an embolus protection filter.