Guidewire with adjustable stiffness

Abstract

A medical guidewire system including an inner member having an outer diameter and an outer member having an inner diameter, the inner diameter being larger than the outer diameter. The inner and outer members are relatively slidable to adjust a stiffness of the guidewire system. The lumen of the outer member forms a gap for fluid flow therethrough. A connector to the inner member and a fluid infusion channel communicating with the gap for injection of fluid through the gap to exit a distal portion of the outer member.

What is claimed is: 
     
         1 . 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.   
     
     
         2 . The guidewire system of  claim 1 , wherein the inner wire member comprises a tip. 
     
     
         3 . The guidewire system of  claim 2 , wherein the tip is integral to the inner wire member. 
     
     
         4 . The guidewire system of  claim 2 , wherein the tip is attached to the inner wire member. 
     
     
         5 . The guidewire system of  claim 2 , wherein the tip is selected from one of a coiled tip, a ball tip, a blunt tip, and a conical tip. 
     
     
         6 . The guidewire system of  claim 1 , wherein the outer tube member comprises a hypotube. 
     
     
         7 . The guidewire system of  claim 1 , wherein the outer tube member comprises a wound wire. 
     
     
         8 . The guidewire system of  claim 7 , wherein the wound wire comprises a rectangular wire. 
     
     
         9 . The guidewire system of  claim 7 , wherein the wound wire comprises a round wire. 
     
     
         10 . The guidewire system of  claim 1 , further including a hydrophilic coating on the outer tube member. 
     
     
         11 . The guidewire system of  claim 1 , wherein the outer tube member comprises a polymeric portion. 
     
     
         12 . The guidewire system of  claim 11 , wherein at least a distal portion of the outer tube member includes the polymeric portion. 
     
     
         13 . The guidewire system of  claim 11 , wherein the polymeric portion includes a coating. 
     
     
         14 . The guidewire system of  claim 13 , wherein the coating comprises a hydrophilic coating. 
     
     
         15 . The guidewire system of  claim 11 , wherein the polymeric portion comprises a heat shrink covering of a polymer. 
     
     
         16 . The guidewire system of  claim 15 , wherein the polymer includes polyethylene terephthalate. 
     
     
         17 . The guidewire system of  claim 1 , wherein the inner member has a polymeric portion comprising a polytetrafluoroethylene or polyethylene terephthalate coating. 
     
     
         18 . The guidewire system of  claim 1 , wherein a portion of the inner member includes a hydrophilic coating. 
     
     
         19 . The guidewire system of  claim 1 , wherein the lumen of the outer tube member forms a gap with the inner wire member for fluid flow therethrough. 
     
     
         20 . The guidewire system of  claim 19 , further including a fluid infusion channel in communication with the gap for injection of fluid through the gap and out of the outer tube member.