Comparison of various cerebral protection devices used for carotid artery stent placement: an in vitro experiment

PURPOSE: To compare the effectiveness of five basic cerebral protection devices designed for carotid angioplasty in an in-vitro bench-top model. MATERIALS AND METHODS: Simulation of embolization from carotid angioplasty (n = 180) was performed with polyvinyl alcohol (PVA) particles (Contour; 150-1,000- micro m) in an open flow model simulating the aortic arch with a carotid bifurcation made from elastic silicone tubes. Particles (150-250 micro m [small], 355-500 micro m [medium], 710-1,000 micro m [large]; 5 mg each) were injected separately into the internal carotid artery (ICA) proximal to the placed protection device. Five devices were tested: the Angioguard (AG), Filter Wire EX (EX(A), EX(B)), Trap, Neuroshield (NS), and GuardWire Plus (GW). Particles getting past the protection device or flowing into the external carotid artery (ECA) were caught in a filter at the end of both arteries and their weight was determined. RESULTS: For small, medium, and large particles, the lowest weight of emboli in the effluent of the ICA was obtained with the NS (0.28 mg, 0.18 mg, and 0.07 mg, respectively; P <.001 compared to all other devices except the GW for small particles only). The GW had the highest embolization rate into the ECA for all particle sizes. When combining the particle weights for the different protection devices, the NS showed the lowest weight of emboli into the ICA filter (0.53 mg/3.5%; P <.001 compared to all [>1.1 mg/7.0%]). The GW revealed the highest weight of emboli into the ECA (1.2 mg/7.6%; P <.001 compared to all [<0.59 mg/0.09%]). Effectiveness of the EX(B) device was enhanced when circumferentially deployed under direct view (EX(B), 0.39 mg/2.58%; EX(A), 1.18 mg/7.81%; P <.001). CONCLUSIONS: In vitro, none of the tested devices or modifications has the ability to prevent embolization completely. An occlusion balloon leads to increased embolization into the ECA. The effectiveness of the EX might be enhanced with design improvements. During this evaluation, the NS was most effective for preventing PVA particle embolization of the three different particle groups within this in-vitro model.