A guidewire (10) includes a flexible elongated core (20) having a proximal end (22) and a distal end (24). An anchor wire (10) has a distal end (34) connected to the distal end (24) of the core (20) and a distally located helical portion (50) that encircles the core. The guidewire (10) has an anchoring condition in which the helical portion (50) is expanded radially away from the core (20). The guidewire (10) has an advancing condition in which the helical portion (50) is stretched longitudinally and contracted radially in response to tension on the anchor wire (30).
