Super Elastic Guidewire With Shape Retention Tip

Abstract

A guidewire having a super elastic core surrounded by a shape memory polymer jacket. The super elastic core wire permits the guidewire to be navigated through tortuous vasculature without undergoing plastic deformation, and the shape memory polymer jacket permits the guidewire to be shaped by the physician.

1 . A method of manufacturing an intravascular guidewire selectively shapeable by a user, the method comprising:
 providing an elongate core wire having a distal tip portion;   surrounding the distal tip portion with a polymer jacket, the polymer comprising a shape memory polymer;   deforming the distal tip portion and the polymer jacket into a desired position;   heating the polymer jacket to a temperature at or above a glass transition temperature of the polymer;   cooling the polymer jacket;   releasing the distal tip portion and the polymer jacket.   
   
   
       2 . The method of  claim 1 , wherein the elongate core wire comprises a super elastic metal. 
   
   
       3 . The method of  claim 2 , wherein the elongate core wire comprises nitinol. 
   
   
       4 . The method of  claim 1 , wherein the elongate core wire comprises stainless steel. 
   
   
       5 . The method of  claim 1 , further comprising disposing a radiopaque coil about the distal tip portion. 
   
   
       6 . The method of  claim 5 , further comprising disposing an inner polymer layer over the radiopaque coil. 
   
   
       7 . The method of  claim 1 , wherein the polymer comprises a material and a thickness sufficient to render the polymer stiffer than the distal tip portion. 
   
   
       8 . The method of  claim 7 , wherein the polymer jacket substantially retains the deformed shape after the distal tip portion has been released. 
   
   
       9 . The method of  claim 1 , further comprising:
 reheating the polymer jacket to a temperature at or above the glass transition temperature of the shape memory polymer such that the polymer jacket returns to its original shape; and   cooling the polymer jacket to a temperature below the glass transition temperature of the polymer.   
   
   
       10 . The method of  claim 1 , further comprising:
 deforming the distal tip portion and the polymer jacket into a different shape;   reheating the polymer jacket to a temperature at or above the glass transition temperature of the polymer; and   cooling the polymer jacket to a temperature below the glass transition temperature.   
   
   
       11 . The method of  claim 1 , wherein a portion of the elongate core wire proximal to the distal tip portion includes a recess having a constant diameter portion and two tapered portions. 
   
   
       12 . The method of  claim 11 , further comprising a shape memory polymer disposed within the recess. 
   
   
       13 . A method of manufacturing an intravascular guidewire selectively shapeable by a user, the method comprising:
 providing an elongate core wire including a constant diameter portion and a tapered distal tip portion extending distally from the constant diameter portion;   surrounding the distal tip portion with a polymer jacket such that the polymer jacket has an outer diameter similar to the constant diameter portion, the polymer comprising a shape memory polymer;   deforming the distal tip portion and the polymer jacket around an object to impart a J-tip shape;   heating the polymer jacket to a temperature at or above a glass transition temperature of the polymer;   cooling the polymer jacket below the glass transition temperature of the polymer;   releasing the distal tip portion and the polymer jacket to result in a final shape of the distal tip portion and the polymer jacket.   
   
   
       14 . The method of  claim 13 , wherein the deformed J-tip shape is exaggerated relative to the final shape of the distal tip portion and polymer jacket. 
   
   
       15 . The method of  claim 13 , wherein the polymer jacket substantially retains the J-tip shape after the distal tip portion and polymer jacket have been released. 
   
   
       16 . The method of  claim 13 , wherein the distal tip portion comprises a series of tapered portions. 
   
   
       17 . The method of  claim 13 , wherein the polymer jacket includes a radiopaque filler. 
   
   
       18 . The method of  claim 13 , further comprising:
 reheating the polymer jacket to a temperature at or above the glass transition temperature of the shape memory polymer such that the polymer jacket returns to its original shape; and   cooling the polymer jacket to a temperature below the glass transition temperature of the polymer.   
   
   
       19 . The method of  claim 13 , further comprising:
 deforming the distal tip portion and the polymer jacket into a different shape;   reheating the polymer jacket to a temperature at or above the glass transition temperature of the polymer; and   cooling the polymer jacket to a temperature below the glass transition temperature.   
   
   
       20 . A method of manufacturing an intravascular guidewire selectively shapeable by a user, the method comprising:
 providing an elongate core wire, formed at least in part of nitinol, the elongate core wire including a constant diameter portion and a tapered distal tip portion extending distally from the constant diameter portion;   surrounding the distal tip portion with a polymer jacket such that the polymer jacket has an outer diameter similar to the constant diameter portion, the polymer comprising a shape memory polymer from a subset of polymers which are characterized by their responsiveness to heating at or above a glass transition temperature of the shape memory polymer to transform the shape memory polymer between a first shape and a second shape;   deforming the distal tip portion and the polymer jacket to impart a desired shape;   heating the polymer jacket to a temperature at or above the glass transition temperature of the polymer;   cooling the polymer jacket to a temperature below the glass transition temperature of the polymer; and   releasing the distal tip portion and the polymer jacket;   wherein after the distal tip portion and polymer jacket have been released, the shape memory polymer overcomes a biasing force of the nitinol wire to substantially maintain the desired shape.