Guidewire with a variable stiffness distal portion
First Claim
Patent Images
1. An intravascular guidewire comprising:
- a) an elongated proximal core section which has proximal and distal ends;
b) an intermediate core section which has proximal and distal ends, which is formed of a shape memory alloy with an Af above 37°
but not more than about 50°
C. and which is secured by its proximal end to the distal end of the proximal core section;
c) a heating mechanism energetically coupled to the intermediate core section to heat the intermediate core section;
d) a distal core section which has proximal and distal ends, at least one distally tapered section, and which is secured by its proximal end to the distal end of the intermediate core section, and which is electrically isolated from the intermediate core section; and
e) a flexible body disposed about and secured to the distal core section.
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Accused Products
Abstract
A guidewire having a core section formed of a NiTi alloy which is in an austenite phase when being manufactured but which is converted to the martensite phase at operating (body) temperature (37° C.) and can be transformed to an austenite phase by heating to a temperature above body temperature but below 50° C. When in the austenite phase, the core section is at a high strength level which ensures the tracking of a catheter over the guidewire within a patient'"'"'s body lumen. In one preferred embodiment the core section is heated by electrical resistance or inductance.
144 Citations
34 Claims
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1. An intravascular guidewire comprising:
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a) an elongated proximal core section which has proximal and distal ends; b) an intermediate core section which has proximal and distal ends, which is formed of a shape memory alloy with an Af above 37°
but not more than about 50°
C. and which is secured by its proximal end to the distal end of the proximal core section;c) a heating mechanism energetically coupled to the intermediate core section to heat the intermediate core section; d) a distal core section which has proximal and distal ends, at least one distally tapered section, and which is secured by its proximal end to the distal end of the intermediate core section, and which is electrically isolated from the intermediate core section; and e) a flexible body disposed about and secured to the distal core section. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. An intravascular guidewire comprising:
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a) an elongated proximal core section which has proximal and distal ends; b) an intermediate core section which has proximal and distal ends, which is formed of a shape memory alloy with an Af above 37°
but not more than about 50°
C. and which is secured by its proximal end to the distal end of the proximal core section;c) a heating mechanism energetically coupled to the intermediate core section to heat the intermediate core section; d) a distal core section which has proximal and distal ends and which is secured by its proximal end to the distal end of the intermediate core section; and e) a flexible body disposed about and secured to the distal core section; f) a first electrical conductor in electrical contact with a proximal extremity of the intermediate core section and a second electrical conductor in electrical contact with a distal extremity of the intermediate core section to facilitate heating the intermediate core section by induction wherein the first and second electrical conductors are layers of electrical conducting material, a first layer of insulating material is disposed on the exterior of the proximal core section, the layer of conducting material of the first electrical conductor is disposed on the layer of insulating material, a second layer of insulating material is disposed on the electrical conducting material of the first electrical conductor and the layer of conducting material of the second electrical conductor is disposed on the second layer of insulating material; and g) a first electrode which is disposed on a proximal portion of the proximal core section and which is electrically connected to the first electrical conductor, and a second electrode which is disposed on the proximal portion of the proximal core section and which is spaced distal to the first electrode and which is electrically connected to the second electrical conductor. - View Dependent Claims (27, 28)
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29. An intravascular guidewire comprising:
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a) an elongated proximal core section which has proximal and distal ends; b) an intermediate core section which has proximal and distal ends, which is formed of a shape memory alloy with an Af above 37°
but not more than about 50°
C. and which is secured by its proximal end to the distal end of the proximal core section;c) a heating mechanism energetically coupled to the intermediate core section to heat the intermediate core section; d) a distal core section which has proximal and distal ends and which is secured by its proximal end to the distal end of the intermediate core section by a cylindrical connecting member formed of a superelastic NiTi alloy with an Af greater than body temperature; and e) a flexible body disposed about and secured to the distal core section.
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30. An intravascular guidewire comprising:
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a) an elongated proximal core section which has proximal and distal ends; b) an intermediate core section having a substantially round transverse cross section which has proximal and distal ends, which is formed of a shape memory alloy with an Af above 37°
but not more than about 50°
C. and which is secured by its proximal end to the distal end of the proximal core section;c) a heating mechanism energetically coupled to the intermediate core section to heat the intermediate core section; d) a distal core section which has proximal and distal ends, at least one distally tapered section, and a length of at least 3 cm, and which is secured by its proximal end to the distal end of the intermediate core section, and which is electrically isolated from the intermediate core section; and e) a flexible body disposed about and secured to the distal core section. - View Dependent Claims (31, 32, 33)
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34. An intravascular guidewire comprising:
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a) an elongated proximal core section which has proximal and distal ends; b) an intermediate core section which has proximal and distal ends, which is formed of a shape memory alloy with an Af above 37°
but not more than about 50°
C. and which is secured by its proximal end to the distal end of the proximal core section by a cylindrical connecting member formed of a superelastic NiTi alloy with an Af greater than body temperature;c) a heating mechanism energetically coupled to the intermediate core section to heat the intermediate core section; d) a distal core section which has proximal and distal ends and which is secured by its proximal end to the distal end of the intermediate core section; and e) a flexible body disposed about and secured to the distal core section.
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Specification