Guidewire with an improved flexural rigidity profile

• US 8,551,021 B2
• Filed: 03/31/2011
• Issued: 10/08/2013
• Est. Priority Date: 03/31/2010
• Status: Expired due to Fees

• Current Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Inventors: Voeller, Virgil F., Northrop, Clay, Layman, Ted
• Primary Examiner(s): HINDENBURG, MAX F
• Application Number:
  US13/077,579
• Publication Number:
  US 20110245808A1
• Time in Patent Office: 922 Days
• Field of Search: 600/585
• US Class Current: 600/585
• CPC Class Codes: A61M 2025/09091 where a sheath surrounds the coil at the distal part
• CPC Class Codes: A61M 2025/09108 Methods for making a guide wire
• CPC Class Codes: A61M 2025/0915 having features for changing the stiffness
• CPC Class Codes: A61M 25/0013 Weakening parts of a catheter tubing, e.g. by making cuts in the tube or reducing thickness of a layer at one point to adjust the flexibility
• CPC Class Codes: A61M 25/0054 with regions for increasing flexibility
• CPC Class Codes: A61M 25/09 Guide wires
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

Medical devices and methods for making and using the same are disclosed. An example medical device may include a guidewire. The guidewire may include a core wire having a distal portion. A tubular member may be disposed over the distal portion. The tubular member may have a plurality of slots formed therein and may have a longitudinal axis. The tubular member may include a variably spaced slot section that has a flexural rigidity that varies from a first flexural rigidity to a second flexural rigidity. The transition from the first flexural rigidity to the second flexural rigidity may be a function of a fourth power equation. The first flexural rigidity may be in the range of about 1×10⁻⁶ to about 9×10⁻⁵ lbs-inches². The second flexural rigidity may be in the range of about 1×10⁻³ to about 5×10⁻³ lbs-inches².

Claims

1. A guidewire, comprising:

a core wire having a distal portion; and

a tubular member disposed over the distal portion, the tubular member having a plurality of slots formed therein and having a longitudinal axis;

wherein the tubular member includes a variably spaced slot section that has a flexural rigidity that varies from a first flexural rigidity to a second flexural rigidity, and wherein the transition from the first flexural rigidity to the second flexural rigidity is a function of a fourth order equation;

wherein the first flexural rigidity is in the range of about 1×

10<sup>−

6</sup> to about 9×

10<sup>−

5</sup> lbs-inches²; and

wherein the second flexural rigidity is in the range of about 1×

10<sup>−

3</sup> to about 5×

10<sup>−

3</sup> lbs-inches².

2. The guidewire of claim 1, wherein the second flexural rigidity is in the range of about 1×

10<sup>−

3</sup> to about 3×

10<sup>−

3</sup> lbs-inches².

3. The guidewire of claim 1, wherein the second flexural rigidity is in the range of about 1.42×

10<sup>−

3</sup> to about 2.64×

10<sup>−

3</sup> lbs-inches².

4. The guidewire of claim 1, wherein the tubular member has a distal end and wherein the tubular member includes a first non-slotted section disposed at the distal end, the first non-slotted section being free of slots.

5. The guidewire of claim 4, wherein the tubular member includes a first constantly spaced slot section that includes slots that have a constant spacing along the longitudinal axis, the first constantly spaced slot section being disposed adjacent to the first non-slotted section.

6. The guidewire of claim 5, wherein the tubular member includes a second constantly spaced slot section that includes slots that have a constant spacing along the longitudinal axis.

7. The guidewire of claim 6, wherein the variably spaced slot section is disposed between the first constantly spaced slot section and the second constantly spaced slot section.

8. The guidewire of claim 7, wherein the tubular member includes a second non-slotted section disposed between the first constantly spaced slot section and the variably spaced slot section, the second non-slotted section being free of slots.

9. The guidewire of claim 8, wherein the tubular member has a proximal end and wherein the tubular member includes a third non-slotted section disposed at the proximal end, the third non-slotted section being free of slots.

10. The guidewire of claim 1, wherein the slots define a beam height for a pair of beams at a longitudinal position along tubular member, wherein a distance between two longitudinally adjacent slots defines a ring width, and wherein the ratio of the beam height to ring width is constant along at least a portion of the tubular member.

11. The guidewire of claim 10, wherein the ratio of beam height to ring width is constant in a first portion of the tubular member and wherein the ratio of beam height to ring width varies in a second portion of the tubular member.

12. The guidewire of claim 11, wherein the ratio of beam height to ring width varies along the variably spaced slot section.

13. The guidewire of claim 1, wherein the slots define beams in the tubular member and wherein at least some of the beams are offset from a centerline of the tubular member.

14. The guidewire of claim 13, wherein the beams are aligned with the centerline along a portion of the tubular member and wherein the beams are offset from the centerline along a second portion of the tubular member.

15. The guidewire of claim 14, wherein the variably spaced slot section includes beams that are offset a distance from the centerline of the tubular member.

16. The guidewire of claim 15, wherein the variable spaced slot section includes a transition where the beams that are offset from the centerline transition from being offset by the distance to beams that are aligned with the centerline of the tubular member.

17. A guidewire, comprising:

a linear-elastic nickel-titanium core wire having a distal portion;

a super-elastic nickel-titanium tubular member disposed over the distal portion, the tubular member having a plurality of slots formed therein and having a longitudinal axis;

wherein the tubular member includes a variably spaced slot section that has a flexural rigidity that varies from a first flexural rigidity to a second flexural rigidity, and wherein the transition from the first flexural rigidity to the second flexural rigidity is a function of a fourth order equation;

wherein the first flexural rigidity is in the range of about 1×

10<sup>−

6</sup> to about 9×

10<sup>−

5</sup> lbs-inches²; and

wherein the second flexural rigidity is in the range of about 1×

10<sup>−

3</sup> to about 5×

10<sup>−

3</sup> lbs-inches².

18. The guidewire of claim 17, wherein the tubular member includes a first constantly spaced slot section and a second constantly spaced slot section that each include slots that are spaced a constant distance along the longitudinal axis.

19. The guidewire of claim 18, wherein the variably spaced slot section is disposed between the first constantly spaced slot section and the second constantly spaced slot section.

20. A method for manufacturing a guidewire, comprising:

providing a tubular member having a longitudinal axis;

forming a first slot in the tubular member at a first position along the longitudinal axis;

forming a second slot in the tubular member at a second position along the longitudinal axis;

forming a plurality of additional slots in the tubular members at a plurality of positions along the longitudinal axis; and

wherein the first slot, the second slot, and the plurality of additional slots are variably spaced along the longitudinal axis so as to define a variably spaced slot section wherein the tubular member includes a variably spaced slot section that has a flexural rigidity that varies from a first flexural rigidity to a second flexural rigidity, wherein the transition from the first flexural rigidity to the second flexural rigidity is a function of a fourth order equation, wherein the first flexural rigidity is in the range of about 1×

10<sup>−

6</sup> to about 9×

10<sup>−

5</sup> lbs-inches², and wherein the second flexural rigidity is in the range of about 1×

10<sup>−

3</sup> to about 5×

10<sup>−

3</sup> lbs-inches².