Shape memory guide wire

Abstract

A guide wire is described for navigating body channels such as vessels. The guide wire can include an elongated member having a proximal portion and a distal portion, and a fluid passage to transport a fluid from the proximal portion to the distal portion. The distal portion of the elongated member can include a shape memory material with two way memory effect. The shape memory material can have a transition temperature less than a body temperature such that the distal portion has a first shape at the body temperature and a second shape different from the first shape at a temperature less than the transition temperature.

1 . A method of using a guide wire comprising:
 inserting a guide wire into a body channel, the guide wire including
 an elongated member having a proximal portion and 
 a distal portion and a fluid passage to transport a fluid from the proximal portion to the distal portion; and 
   selectively transitioning the distal portion of the elongated member between a first shape and a second shape different from the first shape by controlling flow of the fluid through the fluid passage, including
 starting flow of the fluid through the fluid passage to transition the distal portion of the elongated member from the first shape to the second shape and 
 stopping flow of the fluid through the fluid passage to transition the distal portion of the elongated member from the second shape to the first shape. 
   
     
     
         2 . The method of  claim 1 , wherein flow of the fluid through the fluid passage cools the distal portion of the elongated member to a temperature below body temperature at which temperature the distal portion of the elongated member transitions from the first shape to the second shape. 
     
     
         3 . The method of  claim 1 , further comprising navigating the guide wire through the body channel to a desired location after starting flow of the fluid through the fluid passage while the distal portion of the elongated member has the second shape, stopping flow of the fluid through the fluid passage to transition the distal portion of the elongated member from the second shape to the first shape, and continuing to navigate the guide wire through the body channel while the distal portion of the elongated member has the first shape. 
     
     
         4 . The method of  claim 1 , further comprising navigating the guide wire through the body channel to a desired location after stopping flow of the fluid through the fluid passage while the distal portion of the elongated member has the first shape, starting flow of the fluid through the fluid passage to transition the distal portion of the elongated member from the first shape to the second shape, and continuing to navigate the guide wire through the body channel while the distal portion of the elongated member has the second shape. 
     
     
         5 . The method of  claim 1 , further comprising controlling a flow rate of the fluid through the fluid passage to transition the distal portion of the elongated member from the first shape or the second shape to a third shape different from the first shape and the second shape. 
     
     
         6 . The method of  claim 1 , further comprising controlling a temperature of the fluid through the fluid passage to transition the distal portion of the elongated member from the first shape or the second shape to a third shape different from the first shape and the second shape. 
     
     
         7 . The method of  claim 1 , wherein the distal portion of the elongated member comprises a shape memory material with two way memory effect, the shape memory material having a transition temperature less than a body temperature such that the distal portion has the first shape at the body temperature and the second shape at a temperature less than the transition temperature. 
     
     
         8 . The method of  claim 1 , wherein the distal portion comprises a port extending from the fluid passage to an outer surface of the elongated member. 
     
     
         9 . The method of  claim 1 , further comprising an outer member having a secondary passage, the elongated member at least partially disposed within the secondary passage. 
     
     
         10 . The method of  claim 9 , wherein the distal portion of the elongated member comprises a first shape memory material with two way memory effect, the first shape memory material having a transition temperature less than a body temperature such that the distal portion has the first shape at the body temperature and the second shape at a temperature less than the transition temperature, and the outer member comprises a second shape memory material with two way memory effect, the second shape memory material having a transition temperature less than the body temperature. 
     
     
         11 . The method of  claim 10 , wherein the transition temperature of the second shape memory material is substantially the same as the transition temperature of the first shape memory material. 
     
     
         12 . The method of  claim 9 , wherein the outer member comprises an opening extending from the secondary passage to an outer surface of the outer member. 
     
     
         13 . The method of  claim 9 , wherein outer member comprises a coil having windings spaced a distance from one another. 
     
     
         14 . The method of  claim 13 , wherein the distal portion of the elongated member comprises a first shape memory material with two way memory effect, the first shape memory material having a transition temperature less than a body temperature such that the distal portion has the first shape at the body temperature and the second shape at a temperature less than the transition temperature, and the coil comprises a second shape memory material with two way memory effect, the second shape memory material having a transition temperature less than the body temperature. 
     
     
         15 . The method of  claim 13 , wherein the coil extends along the proximal portion and the distal portion of the elongated member, and the guide wire further comprises a tubular sheath covering a proximal portion of the coil while a distal portion of the coil is uncovered by the tubular sheath. 
     
     
         16 . The method of  claim 13 , wherein the distal portion of the elongated member comprises a port extending from the fluid passage to an outer surface of the elongated member. 
     
     
         17 . The method of  claim 16 , wherein the distal portion of the elongated member is radially spaced inward from the coil a distance and the proximal portion of the elongated member is in contact with the coil. 
     
     
         18 . The method of  claim 9 , wherein a distal end of the elongated member is engaged with a distal end of the outer member. 
     
     
         19 . The guide wire of  claim 11 , further comprising a return passage in fluid communication with the fluid passage to transport fluid from the distal portion to the proximal portion, wherein the return passage and the fluid passage are fluidly sealed from an outer surface of the guide wire. 
     
     
         20 . The guide wire of  claim 19 , further comprising an outer member having a secondary passage being the return passage, the elongated member disposed within the secondary passage.