Transcranial Doppler and diffusion-weighted magnetic resonance evaluation of cerebral embolization occurring during transfemoral carotid stenting with proximal flow blockage

BACKGROUND: Transfemoral carotid artery stenting (CAS) with endovascular proximal flow blockage is deemed able to reduce the cerebral embolization observed during filter-protected CAS. We evaluated clinical outcome and intraoperative embolization rates, measured by diffusion weighted magnetic resonance imaging (DW-IVIRI) and transcranial Doppler monitoring, in a series of patients undergoing CAS with proximal flow blockage. METHODS: A series of 35 consecutive patients with symptomatic or asymptomatic internal carotid artery stenosis >= 70% were included to undergo CAS with proximal flow blockage, obtained with the Mo.Ma system. All patients underwent preoperative and postoperative DW-MRI in order to detect new ischemic lesions. Of the 35 patients, 31 (89%) underwent intraoperative transcranial Doppler monitoring to record the microembolic signals (MES) produced during each procedure. RESULTS: The MoMa system was successfully used in 34 patients (technical success: 97%). Intolerance to balloon occlusion was observed in 4 patients (12%), but never compromised the completion of the procedure. No deaths or neurological events occurred in the postoperative period. DW-MRI disclosed 74 new ischemic lesions in 8 patients (8/34, 23.5%). All lesions except one were ipsilateral to the treated carotid artery. MES were detected in all procedures, with a mean number of 33.2 +/- 23.2 (range 3-103). In 20 procedures (20/31, 65%), MES were detected also during flow blockage (mean: 9.1 +/- 7; range 2-28). CONCLUSION: While achieving good technical and clinical results, CAS with proximal flow blockage is still accompanied by a non-negligible cerebral embolization. The detection of MES during ICA flow blockage suggests the need for a better selection of patients.