Multi-property nitinol by heart treatment

a technology of nitinol and heart treatment, applied in the field of shape memory materials, can solve the problems of destroying the superelastic properties of the local treatment area, and achieve the effect of reducing the risk of heart diseas

US20060100693A1Inactive Publication Date: 2006-05-11BOSTON SCI SCIMED INC
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Patent Information

Authority / Receiving Office
US · United States
Patent Type
Applications(United States)
Current Assignee / Owner
Publication Date
2006-05-11
Estimated Expiration
Not applicable · inactive patent

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Abstract

Medical devices may be made of shape-memory materials portions of which have been heat treated to exhibit spatial variations in the stiffness of the material. Devices including stents, vena cava filters and guidewires may be constructed from such materials. Devices may also be made from shape-memory materials which have been locally heat treated such that the superelasticity of the treated portion is destroyed while the remainder of the shape-memory material can transition between the martensitic and austenitic states.
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Description

BACKGROUND OF THE INVENTION

[0001] The present invention is related to the use of shape memory materials in medical devices.

[0002] A shape memory material can assume an initial high temperature configuration and a deformed low temperature configuration and revert back to the initial high temperature configuration upon the application of heat. The high temperature configuration of the material is set into the material or memorized during an initial shaping step in which the material is maintained at a high temperature in a desired shape for a period of time.

[0003] This shape memory exhibited by metals results from the metal undergoing a reversible solid state phase transition. Specifically, the metal transitions from an austenitic state to a martensitic state with a decrease in temperature. The temperature at which the transition begins is typically designated Ms (martensite start temperature) while the temperature at which the transition finishes is designated Mf (martensite finis...

Examples

Embodiment Construction

[0036] While this invention may be embodied in many different forms, there are described in detail herein specific preferred embodiments of the invention. This description is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiments illustrated.

[0037] The present invention is directed to the selective treatment of portions of a medical device containing a shape memory material. More specifically, the invention is directed to differential treatment of the shape memory material in a medical device to achieve different physical properties in different portions of the device.

[0038] Medical devices made of a shape memory material such as Nitinol typically have shape memory characteristics. The shape memory characteristics of the material may be altered by heat treating the material. By locally treating portions of a shape-memory metal, it is possible to produce a metal with spatial variations in the elasticity and sti...