Simulation Study of Distal Balloon Protection Systems during Carotid Artery Stenting

The purpose of our experimental study was to assess the pitfalls of distal balloon protection systems and to learn any technique tips to increase safety. Silicone carotid artery models were connected to a circulatory system to simulate arterial flow. A distal balloon protection device, PercuSurge GuardWire Plus (GWP, Medtronic Vascular) was delivered to the internal carotid artery (ICA), then was inflated to occlude ICA flow temporarily. A debris aspiration catheter (Export catheter) was delivered just proximal to the GuardWire Plus balloon coaxially, in order to introduce and diffuse particulate debris (200-500micro meter in diameter) in the ICA stump. Then, after debris in the stump was aspirated, the GWP balloon was deflated. We recorded all the processes of our simulation experiments on a digital video and observed the movements of debris during these experiments. Exp 1) We simulated the movements of debris in the ICA stump when the GWP balloon was gradually deflated to produce a crevice between the balloon and vessel wall, simulating accidental movement of the GWP balloon during the procedure. Exp 2) In order to assess the optimal placement of the tip of aspiration catheter, the debris in the ICA stump was aspirated from three different sites(from just below the GuardWire balloon, from 2 cm below it, and from 5 cm below it). Exp 1) When the crevice appeared between GuardWire balloon and silicone tube, simulated debris began to concentrate just below the balloon. Then, some debris migrated distally from the crevice, and another part crowded in the crevice so that was impossible to aspirate and migrated in the end. Exp. 2) Debris aspiration was most effective from immediately below the GuardWire balloon, and the aspiration ability declined as the distance between the balloon and aspiration catheter became longer. According to our simulation studies, when the GWP balloon was moved accidentally during CAS procedures, or when the aspiration catheter was not delivered all the way to the GuardWire Plus balloon, distal embolization might still occur, even under protection.