Dual coil steerable guidewire

• US 4,763,647 A
• Filed: 01/06/1987
• Issued: 08/16/1988
• Est. Priority Date: 01/06/1987
• Status: Expired due to Term

• Current Assignee: Medtronic Ave Incorporated (Medtronic Plc)
• Original Assignee: C.R. Bard, Inc. (Becton, Dickinson & Co)
• Inventors: Gambale, Richard A.
• Primary Examiner(s): Coven, Edward M.
• Assistant Examiner(s): SHAY, RANDY CITRIN
• Application Number:
  US07/000,847
• Time in Patent Office: 588 Days
• Field of Search: 128/657, 128/772, 604/95, 604/164, 604/170, 604/280, 604/282
• US Class Current: 600/434
• CPC Class Codes: A61M 2025/09166 having radio-opaque features
• CPC Class Codes: A61M 2025/09175 having specific characteristics at the distal tip
• CPC Class Codes: A61M 25/09033 with fixed mandrils, e.g. mandrils fixed to tip; Tensionable wires

Abstract

A steerable guidewire has an elongate main wire having a tapered distal portion and a helical coil mounted about the distal portion. The distal end of the coil extends beyond the distal tip of the tapered distal portion of the main wire. An inner helical coil is disposed within the outer coil is secured at its proximal end to the distal tip of the tapered distal portion of the main wire and at its distal end to the distal end of the outer coil. The device does not have a separate safety wire, the inner coil serving as the sole safety connection between the main wire and the outer coil. The omission of the conventional safety wire and the use of the dual coil construction provides a tip which is equally flexible in all directions. Gradual selected transitions in stiffness may be achieved by varying the spacing of the individual turns of the inner and outer coils. The guidewire also provides for a change in the radiopacity of the distal portion of the guidewire to provide a more radiopaque segment at the distal portion than at the more proximal portions by forming the inner coil from a more radiopaque material than the outer coil.

Claims

1. A guidewire comprising:

a main wire having a proximal end and a distal end and a distal tapered region;

a first outer helical coil mounted about the tapered region of the main wire and being connected to the main wire at the proximal end of the coil, the distal end of the coil extending distally beyond the distal end of the main wire;

a second, inner, helical coil having a smaller diameter than the first coil and being disposed within the first coil, the second coil being connected at its proximal end to the distal region of the main wire and at its distal end to the distal end of the outer coil;

the second, inner, coil defining a safety means to maintain connection between the main wire and a distal portion of the first coil in the event of breakage of the first coil, said second coil comprising the sole safety means connecting the distal end of the outer coil with the main wire;

the outer and second coils being wound in the same direction.

2. A guidewire as defined in claim 1 wherein said outer coil is connected to the main wire at a location adjacent the distal end of the main wire.

3. A guidewire as defined in claim 2 wherein the outer coil is longer than the second coil.

4. A guidewire as defined in claim 3 wherein one of the coils is formed from a more radiopaque material than the other of the coils.

5. A guidewire as defined in claim 4 wherein the inner coil is more radiopaque than the outer coil.

6. A guidewire as defined in claim 5 wherein the inner coil is formed from an alloy comprising 80% platinum, 15% rhodium and 5% ruthenium.

7. A guidewire as defined in claim 5 wherein the inner coil is formed from an alloy comprising 92% platinum and 8% tungsten.

8. A guidewire as defined in claims 1 or 2 wherein at least one of the coils is formed from an alloy comprising 80% platinum, 15% rhodium and 5% ruthenium.

9. A guidewire as defined in claims 1 or 2 wherein at least one of the coils is formed from an alloy comprising 92% platinum and 8% tungsten.

10. A guidewire as defined in claims 1 or 2 wherein the second coil is formed from wire having a flat rectangular cross section.