Patent ID: 8226704

Claim:
A stent for insertion in a fluid conduit of a human or animal body when the stent is in a collapsed condition and for expansion to an expanded condition, the stent comprising: an outer wall for engagement with the fluid conduit, the outer wall defining an internal diameter of the stent, wherein in the expanded condition the stent has a center line which follows a substantially helical path, so as to promote a swirl flow effect within the fluid conduit supported by the stent, and wherein the stent when expanded ex vivo has a helix angle less than or equal to 65° and a helical center line having an amplitude less than or equal to 0.7 of the internal diameter of the stent; wherein the stent, in the expanded condition, is substantially free of ribs which would project into a flow lumen of the conduit; and wherein the helix angle and/or amplitude of the helical center line varies along the length of the stent so as to introduce a swirl flow effect at an upstream end of the stent and to increase the swirl flow effect in a downstream direction.