A medical device formed of a coil with repeating loops, each loop forming apolygon andeach successive loop being slightly rotated with respect to its adjacent loopsto form a spiralconfiguration. The polygon in a preferred embodiment is a triangle, and therepeating triangularloop coil can be used as a guidewire in a stent delivering catheter. Theguidewire can furtherinclude a stiff core wire that is disposed within the triangular loop coil,where the stiff core wireincludes tapered sections that reduce the stiffness in the distal direction.The coil can includemultiple sections of different loop shapes, including circular, to alter thestiffness of theguidewire to meet the needs of the application.
