Abstract: An endoprosthesis for implantation within a vessel lumen may include a tubular scaffold formed of one or more interwoven filaments, wherein the tubular scaffold is configured to shift between a radially collapsed configuration and a radially expanded configuration, a polymeric covering secured to the tubular scaffold, and an anti-migration element extending radially outward from the tubular scaffold. The anti-migration element extends helically along at least a portion of the length of the tubular scaffold in a first helical direction. The anti-migration element may include a wire extending along an outer surface of the tubular scaffold. The anti-migration element may include a second polymeric covering disposed over the wire.

Abstract: Example expandable stent designs are disclosed. An example expandable stent includes a tubular scaffold including an inner surface, an outer surface and a lumen extending therein. The expandable stent also includes an outer layer disposed along the outer surface of the tubular scaffold and a first preformed flap attached to the outer layer. Additionally, the preformed flap is configured to releasably engage a vessel wall when the stent is implanted therein.