RETRIEVAL DEVICE MADE OF PRECURSOR ALLOY CABLE
First Claim
1. A medical device for use in a body lumen, comprising:
- a self-expanding body formed from struts having a compressed state and an expanded state;
the body including a cold formed nickel-titanium alloy having a transformation temperature greater than a mammalian body temperature, wherein the nickel-titanium alloy exhibits linear pseudoelasticity regardless of stress applied to the body; and
a sheath at least partially enclosing the body in the compressed state.
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Accused Products
Abstract
A medical retrieval device for retrieving foreign objects from a patient and the method of constructing the device are disclosed. The device incorporates a wire cable composed of a precursor alloy to a superelastic material to improve durability of the device. Because precursor alloys exhibit, a linear stress-strain relationship and a yield point associated with a relatively high stress level, the device transfers greater stresses before experiencing deformation. Thus, greater crushing forces can be achieved using a device of this type. These crushing forces may be needed when the foreign object is too large to remove intact. This property also facilitates the device in dilating ducts to retrieve foreign objects. Using the precursor alloy additionally eliminates the need for heat treatment of the cables used in constructing the device. A retrieval device made of precursor alloy cable also is less susceptible to permanent deformation and unwinding during use.
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Citations
21 Claims
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1. A medical device for use in a body lumen, comprising:
- a self-expanding body formed from struts having a compressed state and an expanded state;
the body including a cold formed nickel-titanium alloy having a transformation temperature greater than a mammalian body temperature, wherein the nickel-titanium alloy exhibits linear pseudoelasticity regardless of stress applied to the body; and
a sheath at least partially enclosing the body in the compressed state. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- a self-expanding body formed from struts having a compressed state and an expanded state;
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10. A medical device for use in a body lumen, comprising:
- a self-expanding body formed from struts;
the body including a cold formed nickel-titanium alloy, wherein the nickel-titanium alloy is in a martensitic phase when the body is stressed into a first shape and when the body is stress relieved to a second shape, and wherein the nickel-titanium alloy has a transformation temperature >
37°
C.; and
a sheath at least partially enveloping the body in its first shape. - View Dependent Claims (11, 12, 13, 14, 15)
- a self-expanding body formed from struts;
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16. A method of providing a medical device for use in a body lumen, comprising:
- providing struts including a cold formed nickel-titanium alloy;
setting a transformation temperature >
37°
C.;
cold forming the struts into a body having a shape;
stressing the body into a first shape wherein the nickel-titanium alloy is in a martensitic phase;
providing a sheath;
disposing the body in the first shape at least partially inside the sheath; and
deploying the body from the sheath to stress relieve the body into a second shape, wherein the nickel-titanium alloy remains in the martensitic phase. - View Dependent Claims (17, 18, 19, 20, 21)
- providing struts including a cold formed nickel-titanium alloy;
Specification