Microscopic and macroscopic evaluation of emboli captured during angioplasty and stent procedures in extracranial vertebral and internal carotid arteries

Purpose: To compare the quantities of emboli dislodged during percutaneous transluminal angioplasty/stenting in the vertebral artery (VA) with those released during stent placement in the internal carotid artery (ICA). Methods: Macroscopic images of distal protection devices (DPD) used during 30 stent procedures in 16 ICAs (11 men; mean age 64.6±10.6 years) and 14 VAs (9 men; mean age 67.1 ±9.8 years) were reviewed. The amount of captured embolic debris was calculated and expressed as a proportion to the size of the filter. Histological examinations were performed to characterize the material trapped in the filters. Results: Relative to the size of the filter, the proportion of captured debris ranged from 0.1% to ∼22% in the ostial VA filters and from 0.1% to ∼21% in the filters used in the ICA procedures (p=NS). Plaque fragments with or without thrombus were discovered in the histological examinations of captured material. There were no significant differences in the characteristics of the debris between the 2 vascular regions, nor did sex, race, or plaque morphology correlate significantly with the proportion of captured debris. However, the severity of stenosis was significantly (p<0.029) greater in the ICA (73%±0.11%) than the VA (63%±0.09%) territory. Conclusion: The study suggests that the frequency and amount of captured emboli during stent procedures in ICA and ostial VAs are comparable. Therefore, the use of a DPD for stent placement in the vertebral artery may be advisable.