Guidewire with adjustable stiffness

A guidewire system, comprising:

• an inner wire member having a first outer diameter and a first stiffness, and
• an outer tube member having a lumen for receiving the inner wire member, the diameter of the lumen being larger than the first outer diameter of the inner wire member, the outer tube member further having regions of different flexibility along its length, and a stiffness different than the first stiffness of the inner wire member, and further wherein the outer tube member has a smooth, tapered distal tip for atraumatic entry into a patient,
• the inner wire member and outer tube member being independently slideable and selectively lockable in position relative to one another to function as a unitary guidewire structure for guiding a medical device into the patient, the system being configured such that the inner wire member is capable of being fully retracted within the outer member,
• wherein the selective sliding or locking of the inner wire member and the outer tube member in relative position to one another affects the overall rigidity and diameter of the guidewire system such that the desired degree of pushability, flexibility or stiffness is achieved as the system is advanced into the patient, the system being configured so as to allow adjustment of the overall rigidity without exchange of the members or any portion thereof.