Superelastic guiding member

Abstract

An improved guiding member for use within a body lumen having a unique combination of superelastic characteristics. The superelastic alloy material has a composition consisting of about 30% to about 52% (atomic) titanium, and about 38% to 52% nickel and may have one or more elements selected from the group consisting of iron, cobalt, platinum, palladium, vanadium, copper, zirconium, hafnium and niobium. The alloy material is subjected to thermomechanical processing which includes a final cold working of about 10 to about 75% and then a heat treatment at a temperature between about 450° and about 600° C. and preferably about 475° to about 550° C. Before the heat treatment the cold worked alloy material is preferably subjected to mechanical straightening. The alloy material is preferably subjected to stresses equal to about 5 to about 50% of the room temperature ultimate yield stress of the material during the thermal treatment. The guiding member using such improved material exhibits a stress-induced austenite-to-martensite phase transformation at an exceptionally high constant yield strength of over 90 ksi for solid members and over 70 ksi for tubular members with a broad recoverable strain of at least about 4% during the phase transformation. An essentially whip free product is obtained.

1 - 32 . (canceled)  
     
     
         33 . A guide wire comprising: 
 an elongated core having distal and proximal portions, the core proximal and distal portions, independently including, in atomic percent, from about 30% to about 52% nickel, from about 38% to about 52% titanium, and one or more alloying element selected from the group consisting of iron, cobalt, chromium, platinum, palladium, copper, vanadium, zirconium, hafnium and niobium, wherein the guidewire is an intravascular guidewire.    
     
     
         34 . A guide wire comprising. 
 a proximal and a distal portion each having proximal and distal ends; and    connector connecting the distal end of the proximal portion and the proximal end of the distal portion, the proximal portion, the distal portion, and the connector formed of an alloy composition including, in atomic percent, from about 30% to about 52% nickel, from about 38% to about 52% titanium, and one or more additional alloying elements selected from the group consisting of iron, cobalt, chromium, platinum, palladium, copper, vanadium, zirconium, hafnium and niobium, wherein the guidewire is an intravascular guidewire.    
     
     
         35 . A guide wire having proximal and distal ends comprising: 
 an elongated high strength proximal portion having proximal and distal ends;    a distal portion having proximal and distal ends, the distal portion formed of superelastic alloy composition; and    connector connecting the distal end of the proximal portion and the proximal end of the distal portion and formed at least in part of the superelastic alloy composition, the superelastic composition including, in atomic percent, from about 30% to about 52% nickel, from about 38% to about 52% titanium, and one or more additional alloying elements selected from the group consisting of iron, cobalt, chromium, platinum, palladium, copper, vanadium, zirconium, hafnium and niobium, wherein the guidewire is an intravascular guidewire.