Guide wire core wire made from a substantially titanium-free alloy for enhanced guide wire steering response

Abstract

Guide wire devices and methods for their manufacture. Guide wire devices include an elongate guide wire member that includes at least one section fabricated from a substantially titanium-free Co—Ni—Cr—Mo alloy. The substantially titanium-free Co—Ni—Cr—Mo alloy exhibits superior stiffness (i.e., greater Young's and shear moduli) as compared to stainless steel (e.g., 304V stainless steel) and nickel-titanium (Ni—Ti) and a greater yield strength as compared to stainless steel. Increasing the Young's and shear moduli can significantly improve torque transmission and steerability of the guide wire device and increasing the yield strength can significantly improve the kink resistance of the guide wire device.

What is claimed is: 
     
         1 . A method for fabricating a guide wire device, comprising:
 fabricating an elongate guide wire member having a proximal section and a distal section, wherein at least the distal section is fabricated from a cobalt-nickel-chromium-molybdenum (Co—Ni—Cr—Mo) alloy that comprises less than 0.05% of titanium by weight; and   imparting at least 50% to 95% cold work to at least a portion of the Co—Ni—Cr—Mo alloy to yield a Co—Ni—Cr—Mo alloy having a Young's modulus of at least about 230 GPa and a yield strength of about 1 GPa to about 2 GPa.   
     
     
         2 . The method of  claim 1 , wherein the method further comprises one or more of:
 grinding the distal end section to a distally tapered cross sectional dimension of about 0.1 mm to about 0.05 mm;   disposing a helical coil section about at least a distal end portion of the distal section and joining the helical coil to the elongate guide wire member at a proximal location;   forming a rounded cap section on a distal end of the elongate guide wire member; or   applying at least one lubricious outer coating layer over at least a portion of the elongate guide wire member.   
     
     
         3 . The method of  claim 1 , wherein the cold work includes one or more of drawing, swaging, cold rolling, stamping, extrusion, forging, or flattening. 
     
     
         4 . The method of  claim 1 , further comprising:
 fabricating the distal section of the elongate guide wire member from the Co—Ni—Cr—Mo alloy;   cold working at least a portion of the Co—Ni—Cr—Mo alloy to yield a cold worked section that exhibits at least about 50-95% cold work.   
     
     
         5 . The method of  claim 1 , further comprising:
 fabricating the proximal and distal sections of the elongate guide wire member from the Co—Ni—Cr—Mo alloy;   cold working at least a portion of the Co—Ni—Cr—Mo alloy to yield a cold worked section that exhibits at least about 50-95% cold work.   
     
     
         6 . The method of  claim 1 , wherein the Co—Ni—Cr—Mo alloy comprises:
 about 31.5 wt % to about 39 wt % cobalt; 
 about 33 wt % to about 37 wt % nickel; 
 about 19 wt % to about 21 wt % chromium; 
 about 9 wt % to about 10.5 wt % molybdenum; and 
 less than about 0.05 wt % titanium. 
 
     
     
         7 . The method of  claim 1 , wherein the Co—Ni—Cr—Mo alloy exhibits about 80% to about 95% cold work. 
     
     
         8 . A method for fabricating a guide wire device, comprising:
 fabricating an elongate guide wire member having a proximal section and a distal section, wherein at least the distal section is fabricated from a cobalt-nickel-chromium-molybdenum (Co—Ni—Cr—Mo) alloy that comprises less than 0.05% of titanium by weight;   grinding the distal end section to a distally tapered cross sectional dimension of about 0.1 mm to about 0.05 mm;   imparting at least 50% to 95% cold work to at least a portion of the Co—Ni—Cr—Mo alloy to yield higher Young's and shear moduli and greater yield strength, as compared to a non-cold worked portion of the Co—Ni—Cr—Mo alloy;   disposing a helical coil section about at least a distal end portion of the distal section;   joining the helical coil to the elongate guide wire member at a proximal location;   forming a rounded cap section on a distal end of the helical coil; and   applying at least one lubricious outer coating layer over at least a portion of the elongate guide wire member to form the guide wire device.   
     
     
         9 . The method of  claim 8 , wherein the cold work includes one or more of drawing, swaging, cold rolling, stamping, extrusion, forging, or flattening. 
     
     
         10 . The method of  claim 8 , further comprising:
 fabricating the distal section of the elongate guide wire member from the Co—Ni—Cr—Mo alloy;   cold working at least a portion of the Co—Ni—Cr—Mo alloy to yield a cold worked section that exhibits at least about 50-95% cold work.   
     
     
         11 . The method of  claim 8 , further comprising:
 fabricating the proximal and distal sections of the elongate guide wire member from the Co—Ni—Cr—Mo alloy;   cold working at least a portion of the Co—Ni—Cr—Mo alloy to yield a cold worked section that exhibits at least about 50-95% cold work.   
     
     
         12 . The method of  claim 8 , wherein the cold worked Co—Ni—Cr—Mo alloy has a Young's modulus of at least about 230 GPa and a yield strength of about 1 GPa to about 2 GPa. 
     
     
         13 . The method of  claim 8 , wherein the Co—Ni—Cr—Mo alloy comprises:
 about 31.5 wt % to about 39 wt % cobalt; 
 about 33 wt % to about 37 wt % nickel; 
 about 19 wt % to about 21 wt % chromium; 
 about 9 wt % to about 10.5 wt % molybdenum; and 
 less than about 0.05 wt % titanium. 
 
     
     
         14 . The method of  claim 8 , wherein the Co—Ni—Cr—Mo alloy exhibits about 80% to about 95% cold work. 
     
     
         15 . A method for fabricating a guide wire device, comprising:
 fabricating an elongate guide wire member having a proximal section joined to a distal section, wherein the distal section is fabricated from a cobalt-nickel-chromium-molybdenum (Co—Ni—Cr—Mo) alloy that comprises less than 0.05% of titanium by weight and wherein the proximal section is fabricated from a stainless steel alloy;   imparting at least 50% to 95% cold work to at least a portion of the Co—Ni—Cr—Mo alloy to yield higher Young's and shear moduli and greater yield strength, as compared to the proximal section.   
     
     
         16 . The method of  claim 1 , wherein the method further comprises one or more of:
 grinding the distal end section to a distally tapered cross sectional dimension of about 0.1 mm to about 0.05 mm;   disposing a helical coil section about at least a distal end portion of the distal section and joining the helical coil to the elongate guide wire member at a proximal location;   forming a rounded cap section on a distal end of the elongate guide wire member; or   applying at least one lubricious outer coating layer over at least a portion of the elongate guide wire member.   
     
     
         17 . The method of  claim 15 , wherein the cold work includes one or more of drawing, swaging, cold rolling, stamping, extrusion, forging, or flattening. 
     
     
         18 . The method of  claim 15 , wherein the cold worked Co—Ni—Cr—Mo alloy has a Young's modulus of at least about 230 GPa and a yield strength of about 1 GPa to about 2 GPa. 
     
     
         19 . The method of  claim 15 , wherein the Co—Ni—Cr—Mo alloy comprises:
 about 31.5 wt % to about 39 wt % cobalt; 
 about 33 wt % to about 37 wt % nickel; 
 about 19 wt % to about 21 wt % chromium; 
 about 9 wt % to about 10.5 wt % molybdenum; and 
 less than about 0.05 wt % titanium. 
 
     
     
         20 . The method of  claim 15 , wherein the Co—Ni—Cr—Mo alloy exhibits about 80% to about 95% cold work. 
     
     
         21 . The method of  claim 15 , further comprising:
 forming the proximal section to have a cross sectional diameter of 0.3 mm to 0.5 mm; and   forming the distal section to have a ground surface defining a second, smaller cross sectional dimension with a distal taper section having a cross sectional diameter of 0.1 mm to 0.05 mm.