EP0491349A2
Expired / Lapsed
EP
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Superelastic guiding member
Assignee: Abbott Cardiovascular Systems Inc
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Filing: 1991-12-17
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Granted: —
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Expires: 2011-12-17
Abstract
Abstract An improved guiding member for advancing a catheter within a body lumen having a unique combination of superelastic characteristics. The superelastic alloy material has a composition consisting of titanium and nickel and may have one or more elements selected from the group consisting of iron, cobalt, vanadium and copper. The alloy material is cold worked and then heat treated at a temperature well above the austenite-to-martensite transformation temperature, while being subjected to longitudinal stresses equal to about 5 to about 50% of the room temperature yield stress to impart to the metal a straight "memory". The guiding member using such improved material exhibits a stress-inducedaustenite-to-martensite phase transformation at an exceptionally high constant yield strength of at least 90 ksi for solid members and at least 70 ksi for tubular members with a broad recoverable strain of at least about 4% during the phase transformation.
Inventors
- 👤 Robert M. Abrams
- 👤 Sepehr Fariabi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 23:12
CPC Classifications
C; C22; C22F; C22F1/00; C22F1/006; A; A61; A61L; A61L31/00; A61L31/02; A61L31/022; A61M; A61M25/00; A61M25/01; A61M25/09; C22C; C22C14/00; C22C30/00; A61L2400/00; A61L2400/16; A61M2025/09008; A61M2025/09058; A61M2025/09083; A61M2025/09133; A61M2025/09141; A61M2025/09175; A61M2205/00; A61M2205/02; A61M2205/0266
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
110 words
An intravascular guidewire comprising a) an elongated member having a proximal portion and a distal portion and being formed at least in part of an superelastic alloy having an austenite phase which is stable at a temperature below body temperature, which transforms to a martensite phase at a stress above about 70 ksi and which exhibits a strain of at least about 4% from the stress applied to induce the austenite to martensite phase transformation; b) a flexible body disposed about the distal portion; and c) means on the proximal end of the elongated member to torque this member and transmit such torque to the distal end of the guidewire.
Claim 2
Dependent Claim
47 words
The guidewire of claim 1 wherein the distal section of the elongated member terminates short of the distal extremity of the guidewire and a shaping ribbon extends from the distal end of the elongated member to a rounded plug on the distal end of the flexible body.
Claim 3
Dependent Claim
13 words
The guidewire of claim 1 wherein the superelastic portion has a straight memory.
Claim 4
Dependent Claim
55 words
A superelastic body formed of an alloy having an austenite phase which is stable at a desired operating temperature, which will transform to martensite phase upon the application thereto of a stress, the body exhibiting a recoverable strain of at least about 4% upon the application of the stress which induces the austenite-to-martensite phase transformation.
Claim 5
Dependent Claim
16 words
The body of claim 4 wherein the body exhibits a strain of at least about 5%.
Claim 6
Dependent Claim
32 words
The body of claim 5 wherein the strain of the body during the transformation from the austenite phase to the martensite phase is within the range of about 2% to about 8%.
Claim 7
Dependent Claim
20 words
The body of claim 4 wherein the austenite-to-martensite transformation occurs at a relatively constant yield stress above about 90 ksi.
Claim 8
Dependent Claim
29 words
The body of claim 4 wherein the alloy consists essentially of about 40 to about 49% titanium and the balance nickel and up to 10% of other alloying elements.
Claim 9
Dependent Claim
22 words
The body of claim 8 wherein the other alloying elements are selected from the group consisting of iron, cobalt, vanadium and copper.
Claim 10
Dependent Claim
29 words
The body of claim 9 wherein the alloy contains vanadium or copper in amounts up to about 10% and the other alloying elements in amounts up to about 3%.
Claim 11
Dependent Claim
24 words
The body of claim 4 wherein the distal portion thereof has a plurality of sections which have progressively smaller cross-sections in the distal direction.
Claim 12
Dependent Claim
16 words
The body of claim 4 further comprising a flexible member disposed about the distal portion thereof.
Claim 13
Dependent Claim
22 words
The body of claim 12 wherein the flexible member is a helical coil with a rounded plug on the distal end thereof.
Claim 14
Dependent Claim
16 words
The body of claim 4 wherein a lubricous polymer coating covers at least a portion thereof.
Claim 15
Dependent Claim
40 words
The body of claim 4 wherein the elongated body terminates short of the distal end of the flexible member and a shaping ribbon extends from the distal end of the elongated body to the distal end of the flexible body.
Claim 16
Dependent Claim
122 words
A fixed-wire balloon angioplasty catheter comprising: a) an elongated catheter body with an inner lumen extending therein; b) an inflatable balloon on the distal extremity of the catheter body and having an interior in fluid communication with the inner lumen of the catheter body; and c) a guiding member which is disposed within the inner lumen of the catheter body and which is formed at least in part of a superelastic alloy having an austenite phase which is stable at a temperature below body temperature and which transforms to martensite at a stress above about 70 ksi, the body exhibiting a strain of at least about 4% upon the application of the stress which induces the austenite phase to transform martensite phase.
Claim 17
Independent Claim
111 words
A method of forming a superelastic elongated member having a straight memory comprising: providing an elongated member formed of an alloy consisting essentially of about 40 to about 49% titanium and the balance nickel and up to about 10% of an element selected from the group consisting of iron, cobalt, chromium and vanadium; cold working the elongated member to effect a size reduction of about 30 to about 70%; and heat treating the cold worked elongated member at a temperature between about 350 and about 600° C while subjecting the cold worked elongated member to a longitudinal tension of about 5 to about 50% of the yield strength of the metal.
Claim 18
Independent Claim
94 words
A method of forming a superelastic elongated member having a straight memory comprising: providing an elongated member formed of an alloy consisting essentially of about 40 to about 49% titanium and the balance nickel and up to about 10% of an element selected from the group consisting of iron, cobalt, chromium and vanadium; cold working the elongated member to effect a size reduction of about 30 to about 60%; mechanically straightening the cold worked elongated member; heat treating the straightened, cold worked elongated member at a temperature between about 300 and about 400° C.
Claim 19
Independent Claim
27 words
The method of claims 17 or 18 which includes the step of heat treating the elongated member to relieve internal stress prior to the cold working thereof.
Claim 20
Independent Claim
21 words
The method of claims 17 or 18 wherein the cold-worked metal is heat treated from about 0.5 to about 60 minutes.
Claim 21
Independent Claim
48 words
The device of any one of claims 4 to 14 further comprising an elongated tubular body suitable for use in a medical device within a human body having a continuous cylindrical wall defining an inner lumen therein which is formed at least in part of said superelastic alloy.
Claim 22
Dependent Claim
29 words
The tubular body of claim 21 wherein the stress level at which the austenite phase transforms to the martensite phase at a relatively constant level is above 70 ksi.
Claim 23
Independent Claim
30 words
The device of any one of claims 4 to 14 and 22 further comprising an elongated body for intravascular devices having a straight memory and being formed of said alloy.
Claim 24
Dependent Claim
28 words
The tubular body of claim 23 having an outer diameter of about 0.006 to about 0.05 inch and a wall thickness of about 0.001 to about 0.004 inch.
References Cited (Backward Citations)
No citation records indexed.
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