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

AIM

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-MRI) 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.