Cerebral protection during carotid artery stenting: collection and histopathologic analysis of embolized debris.

BACKGROUND AND PURPOSE Histopathologic analysis was performed to better understand quantity, particle size, and composition of embolized debris collected in protection filters during carotid artery stent implantation. METHODS Elective carotid stent implantation with the use of a distal filter protection was attempted in 38 consecutive lesions (36 patients) of the internal carotid artery presenting >70% diameter stenosis (mean, 82.1+/-11.1%). Mean age of the patients was 70.7+/-7.7 years; 75% were men, and 50% of patients had previous neurological symptoms. RESULTS In 37 lesions (97.4%) it was possible to position the filter device, and in all lesions a stent was successfully implanted. The only complication occurring in the hospital and during the 30-day follow-up was 1 death due to acute myocardial infarction. Neurological sequelae did not occur. Histomorphometric analysis was performed on the filters. Presence of debris was detected in 83.7% of filters. The mean surface area of the polyurethane membrane filter covered with material was 53.2+/-19.8%. Particle size ranged from 1.08 to 5043.5 microm (mean, 289.5+/-512 microm) in the major axis and 0.7 to 1175.3 microm (mean, 119.7+/-186.7 microm) in the minor axis. Collected debris consisted predominantly of thrombotic material, foam cells, and cholesterol clefts. CONCLUSIONS By the use of distal protection filters during carotid artery stenting, it was possible to collect particulate debris potentially leading to distal vessel occlusion in a high percentage of cases. Qualitative analysis of embolized material showed debris dislocated during the percutaneous intervention from atheromatous plaques.