A tapered helical implantation device for peripheral arteries and other body lumina of locally varying diameter, including struts connected by loops and shaped in a helical winding. The helical winding defines turns and, when expanded, has a first end with a first expanded circumference and a second end with a second expanded circumference greater than the first expanded circumference to form a stent tapering outward from the first end towards the second end. Bridges connect adjacent ones of the turns. The struts, the loops, and the bridges define a series of pores aligned along the helix, the pores having a substantially uniform pore size. The pores has a substantially similar area. The pore size limits a size of a particle that can pass therethrough. In particular, the pore size limits a size of a spherical particle that can pass therethrough.
