Disclosed is an anchoring element for an implantable prosthesis that includes a barb, wherein the anchoring element, which includes a basal portion, comprises a thin layer of material, such as a cannula or sheet of metal, that extends or wraps at least partially around the strut of the prosthesis to which it is attached. The barb is configured to extend outward from the basal portion to penetrate adjacent tissue. The anchoring element is either permanently affixed to the strut, such as by laser or spot welding, crimping, or some other method of bonding, or allowed to slide longitudinally over the strut between two points or stops in order to relieve any excessive loads placed upon the barb that could cause fracture. The anchoring element and strut may be configured to limit axial rotation of the barb, while still allowing longitudinal movement. In another embodiment, the slidable anchoring element may be manipulated following initial deployment to reorient the barb toward the implantation site.