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.