Embolization via collateral circulation during carotid stenting with the distal balloon protection system

Purpose: To describe a potential route for embolization to the middle cereb ral artery (MCA) during carotid stenting with the distal balloon protection system. Case Report. An 82-year-old man with symptomatic severe carotid artery sten osis underwent elective carotid stenting with distal-balloon protection. De spite complete occlusion of the distal internal carotid artery, frequent em boli were detected in the ipsilateral MCA by transcranial Doppler (TCD) dur ing the procedure. Intracranial angiography, performed during the distal-ba lloon protection, revealed filling of the MCA through collaterals from the ipsilateral external carotid artery. The procedure was successfully complet ed without complications. The patient remains asymptomatic at 6 months. Conclusions: During carotid stenting with distal-balloon protection, asympt omatic embolization into the ipsilateral MCA may occur through collateral c irculation. The clinical significance of these emboli is uncertain.