New cerebral ischemic lesions after carotid endarterectomy.

BACKGROUND

We sought to investigate the incidence and location of new cerebral ischemic lesions after carotid endarterectomy (CEA) using diffusion-weighted magnetic resonance imaging (DW-MRI).

METHODS

Sixty-six consecutive patients (50 males with a mean [±SD] age of 69 ± 9 years) who underwent CEA were included in this prospective study. Seventeen patients were symptomatic and 49 patients were asymptomatic. CEA was performed with patch closure without using a shunt. Carotid plaque echostructure was evaluated with the grayscale median (GSM) score. DW-MRI scanning of the brain was performed 24 hours before and 48 to 72 hours after the procedure.

RESULTS

Thirty-day stroke and mortality rates were 0%. The mean GSM score for symptomatic patients was 27 ± 15; for asymptomatic patients, the mean GSM score was 39 ± 18 (P = 0.006). Patients were divided into 2 groups according to GSM score: GSM scores ≤25 (22 patients) and GSM scores >26 (44 patients). New brain lesions were detected after 6 endarterectomies (8.9%), and all were clinically silent. These lesions were ischemic in 5 cases (7.5%) and micro-hemorrhagic in 1 case (1.4%). In 3 cases, new ischemic lesions were located within the treated carotid artery territory. In 2 cases, new lesions on DW-MRI were located outside of the treated carotid artery territory. There was no significant difference in the incidence of ischemic lesions between the 2 groups (GSM scores ≤25, 2 lesions; GSM scores >26, 3 lesions; P = 0.544).

CONCLUSIONS

New ischemic lesions on DW-MRI are detected in 7.5% of patients after CEA, and most of these lesions are clinically silent. Plaque echogenicity does not affect their incidence. New lesions seen on DW-MRI may be generated outside of the treated carotid artery territory.