Aim: Intraoperative cerebral embolization is a greater concern in patients undergoing carotid-artery stenting (CAS) than in those undergoing the reference standard treatment carotid endarterectomy (CEA). We evaluated cerebral embolism with diffusion-weighted magnetic resonance imaging (DW-MRI) and transcranial Doppler monitoring during CAS and CEA.
Methods: A series of 75 patients with carotid stenosis, 40 undergoing CEA and 35 transfemoral protected CAS, underwent preoperative and postoperative cerebral DW-MRI. Of the 75 patients, 64 (85%) underwent intraoperative transcranial Doppler monitoring to evaluate the mean number of microembolic signals (MES) recorded in each procedure.
Results: None of the patients died. No patient in the CEA but two in the CAS group had strokes (5.7%, P=NS). The mean MES count on transcranial Doppler monitoring was higher in the CAS than in the CEA group (330.0 MES, range 2754 vs 13.2, range 0-49 MES; P<0.01). DW-MRI disclosed a significantly larger number of new ischemic lesions in the CAS than in the CEA group (40 lesions in 12/35 patients, 34.3% vs 4 lesions in 3/40 patients, 7.5%; P<0.01). In the CEA group, all patients with ischemic lesions were asymptomatic whereas in the CAS group 5 were symptomatic (14.3%) and 7 asymptomatic (20%). The cerebral distribution also differed in the two groups: no CEA but 20% of CAS lesions were contralateral.
Conclusion: CAS is associated with a significantly higher rate of cerebral embolization than CEA. Even though the clinical meaning of new postoperative ischemic lesions remains debatable, it seems prudent to reduce the embolic load by improving procedural techniques and cerebral protection devices.