A new concept for covered stent protected carotid angioplasty: an ex vivo study

Objective: To determine the efficacy of a covered stent prototype designed for protected carotid angioplasty to reduce cerebral embolization. Material and Method: The covered stent tested is made of nitinol, coated with a polyurethane membrane (MembraXTM; porous size 80 μm). In a bench-top model (flow-rate 650 ml/min, pulsatile flow [dicrote] 123 Pulses/min, pressure 100/60 mm Hg [mean pressure 80 mmHg]) with inserted human carotid (n=6) stent implantation was performed (8/32 mm). Passed particles (mg) were determined in the effluent of a 100 μm filter prior to intervention, after stent deployment and after final dilation (5 mm). Results: When stenting carotid arteries obtained from human cadavers, the highest rate of particle embolization was measured while crossing the lesion with the delivery device (6,8 mg; for all p<0,05), embolization after additional balloon angioplasty and particle rates measured in the effluent filter prior covered stent placement were significantly lower (3,8 mg; p<0,05). Branches of the external carotid artery remained patent in all cases. Conclusions: The introduced concept of covered stent protected carotid angioplasty with the MembraXTM prototype has proven promising results for low cerebral embolization rates ex vivo. Further evaluations using an animal model and a miniaturization of the delivery device are warranted prior to human use. (orig.)