A balloon catheter having wires situated between an outer layer and a surface of a balloon is described. Each wire may be confined within an interior space of a pocket or encapsulated within a sheath. The pocket includes the outer layer and the balloon surface. The outer layer and balloon surface are unattached to allow the wire to slidably fit between therewithin. The pocket is selectively bonded to the balloon. The sheath includes a preformed shape that completely circumscribes the wire along the longitudinal and radial directions of the wire. The confined and encapsulated feature of the wires enable the wires to be atraumatic and remain spaced apart during treatment of calcification of a lesion.
