The Effect of Embolic Protection Filters on Distal Embolization and Slow Flow Condition in Carotid Artery Stenting

Strokes are the third leading cause of death in the United States today. Carotid artery stenting (CAS) used in conjunction with a cerebral protection device (CPD) is a current alternative treatment for severe carotid artery disease. A type of CPD, an embolic protection filter (EPF), has received attention recently due to its allowance of distal perfusion during use. This investigation studied the effects of four EPFs (Spider RX, FilterWire EZ, RX Accunet, Emboshield) on both pressure gradient and flow rate in the internal carotid artery (ICA) in vitro. Dyed polymer microspheres larger than the pore size of the devices tested were injected into the ICA of a 70% stenosed carotid artery model. The percentage of particles missed was calculated. None of the devices tested were able to completely prevent embolization. Emboshield had the least desirable performance (missing 35.4% of particles) while Spider RX had the best (missing 0.06%). A decrease in flow rate and an increase in pressure drop were seen after the device was filled with particles. From these results, it is inferred that improper wall apposition is the primary cause for inadequate capture efficiency rates, which may lead to an increase in distal embolization and stroke.