Comparison of 4 cerebral protection filters for carotid angioplasty: an in vitro experiment focusing on carotid anatomy.

PURPOSE: To assess the influence of internal carotid artery (ICA) tortuosity on the effectiveness of 4 cerebral protection filters in an in vitro bench-top model. METHODS: To simulate the anatomical arterial variants, 3 open flow models were constructed: one with normal carotid anatomy, 1 representing a mildly tortuous ICA, and a third imitating a severely tortuous ICA. Polyvinyl alcohol particles (150-1000 microm) served as the embolic material; the emboli were divided into 3 groups according to size: small (150-250 microm), medium (355-500 microm), and large (710-1000 microm). Five milligrams of each size group were injected separately into the ICA proximal to each of 4 protection filters: AngioGuard, FilterWire EX, TRAP, and NeuroShield. Emboli that were not caught by the protection system or were washed into the external carotid artery (ECA) ran into an effluent filter and were weighed and classified according to size. RESULTS: In 240 test runs, the FilterWire EX presented the lowest weight of emboli in the ICA effluent under all anatomical conditions: normal anatomy 0.39 mg (2.58%), mild tortuosity 0.45 mg (2.99%), and severe tortuosity 0.50 mg (3.33%) (p>0.05). The Angioguard system showed the worst results: normal 1.21 mg (98.03%), mild tortuosity 2.54 mg (16.84%), and severe tortuosity 3.14 mg (20.91%) (p<0.001) compared to the FilterWire EX and the NeuroShield systems. The only protection device displaying no significant differences in all of the 3 emboli sizes was the FilterWire EX (p>0.05). Relevant differences in effectiveness in mildly and severely tortuous ICAs were apparent among the other devices. For all emboli sizes, the differences of the AngioGuard and TRAP systems were highly significant (p<0.001). There was no significant difference between the FilterWire EX and the NeuroShield. CONCLUSIONS: The only protection device showing no significant decrease in efficacy in the tortuous ICA models was the FilterWire EX. In both tested anatomical variants, the protection systems ranked in the same order of effectiveness. None of the tested devices prevented embolization completely.

Management of unexpected balloon rupture during deployment of balloon-expandable stents.

PURPOSE: To describe a method for dealing with balloon rupture during stent deployment. TECHNIQUE: A 10-mL Luer-Lock syringe containing contrast material and heparinized saline is used to re-expand a balloon ruptured during stent deployment, permitting maximum balloon expansion and successful initial stent-wall apposition. No adjunctive use of probing catheters or a power injector is necessary to achieve adequate stent expansion. Analysis of the rupture may identify procedural deficiencies that can be rectified. CONCLUSIONS: This technique is simple and timesaving, and interventionists should maintain vigilance when handling of balloon-expandable stents.