A double guide wire includes two guidewires (100, 300) deployed concentrically, one within the other, Each guidewire is formed as an elongated flexible shaft (1 10, 120, 310. 320) having a distal portion including a deflectable helical coil (111, 314) terminating at a distal tip (11 5, 311). The first guidewire (100) is implemented as a hollow guidewire having a central lumen (150) extending along: its length, while the second guidewire (300) is configured as a smaller gauge guidewire deployed within the central lumen of the first guidewire. Art adjuster mechanism (210) allows the inner guidewire to be advanced and retracted relative to the outer guidewire, transforming the guidewire between! a first state in which the distal, tip of the second guidewire is adjacent to the distal tip of the first guidewire； and a second state in which at least part of the distal portion of the inner guidewire is advanced beyond distal tip of the first guidewire.
