Study of conformability of the new leo plus stent to a curved vascular model using flat-panel detector computed...

In a previous study, we assessed the conformability limitations of self-expandable stents to a curved vascular model. The LEO stent (Balt Extrusion, Montmorency, France), one of the current self-expandable models available for intracranial aneurysm stenting, displayed 2 adverse mechanics: flattening of the stent midsection and inward crimping of the proximal and distal ends. We present a follow-up study in which we evaluate the conformability to curved vessels of a second-generation stent, LEO PLUS.

A 3.5-x 25-mm LEO PLUS stent was deployed inside a 3-mm x 10-cm polytetrafluoroethylene tube (vascular model) with a simulated 5-mm aneurysm neck at its midsection. The polytetrafluoroethylene tube was then placed in a polystyrene block (styrofoam; Dow Chemical Co., Midland, MI) and bent at different angles ranging from 0 to 150 degrees. For each angle, a rotational radiogram was performed using a C-arm angiographic system with a 30-x 43-cm CsI/amorphous silicon flat detector operated with 23-second rotations, 0.80-degree increments, 166 projections, and a 2480 x 1920 matrix (2K matrix).

The LEO PLUS stent showed symmetric deployment at all tested degrees of curvature, without flattening or kinking. The stent retained its round cylindrical shape at all curvatures without inward crimping of its proximal and distal ends.

The previously documented adverse mechanics of the LEO stent were not observed with the new LEO PLUS stent. This suggests better conformability to curved or tortuous vasculature owing to design improvements.