Embolism to the brain during carotid stenting and surgery

The aim of this study was to assess the prevalence and clinical relevance of microembolism in one hundred unselected patients submitted to 50 carotid endarterectomy (CEA) and 50 carotid stenting (CAS) procedures from January 2005 to January 2006 for hemodynamic lesions of the carotid bifurcation (> 70% stenosis). Material and methods: High-resolution Colour-Flow Mapping (CFM), Transcranial Doppler (TCD), cerebral computed tomography (CT) or magnetic resonance (MR) and four psychometric tests (Mini mental state, Beck depression inventory, Zung anxiety inventory, SF-12) were carried out in the preoperative evaluation in all the patients. In the CEAs loco-regional anesthesia (100%), patch angioplasty (84%) and Pruitt- Inahara shunt (4%) were employed; in the CASs local anesthesia (100%), three different carotid stents (Precise-Cordis, Acculink-Guidant and Carotid Wallstent-Boston Scientific) and three temporary distal filter protection devices (Angioguard-Cordis, Accunet-Guidant, Filterwire-EZ- Boston Scientific), without pre-dilatation, were employed. TCD monitoring was used intra-operatively and 12 hours post-operatively to evaluate the presence and the number of microembolic events (ME's) and to investigate the efficiency of neuroprotective filter devices. The efficacy of the in situ opened filter was judged evaluating the decrease of mean blood velocity in ipsilateral middle cerebral artery and the reduction rate of microembolic events (number of microemboli detected during the entire procedure/number of microemboli detected during the filter positioning). Diffusion-weighted magnetic resonance imaging (DWI) of the brain was obtained within 24 to 48 hours after the procedures to detect new ischemic brain lesions. Psychometric tests were repeated at the discharge of the patient and after two months to evaluate cognitive faculties. Results: During postoperative period (30 days) and follow-up, no procedure-related death and three regressive minor strokes occurred: 1 in CEA (2%) and 2 in CASs (4%); a cranial nerve lesion occurred in CEA (2%). TCD monitoring showed ME's (a mean of five events) in 37 CEAs (74%) and in 50 CASs (100%) (a mean of 60 ME's). In five patients submitted to CAS repeated microemboli occurred during one hour postoperative TCD control (10%). A 10-30% decrease of mean blood velocity basal value was recorded in the ipsilateral middle cerebral artery when the filter device was opened. A mean 70% reduction of ME's was obtained with a cerebral protection system deployed. Postoperative DWI detected new focal ischemic lesions in 24 patients [22 after CAS (44%) (a mean of 5 new ipsi and contra-lateral lesions), and 2 after CEA (4%). Cognitive capability worsened in 20 patients [18 after CAS (36%) e 2 after CEA (4%)]. Conclusions: Mortality and morbidity rates of patients submitted to CAS are comparable to the results obtained by CEA. A great number of ME's are recorded by TCD during endovascular procedures, more than during open surgery. ME's due to CAS are reduced by filter protection devices, but the cognitive faculties in a great number of "asymptomatic" patients are decreased after CAS. (C) 2007 The Royal Belgian Society for Surgery