System for bi-directionally controlling the cryo-tip of a cryoablation catheter

• US 20050288656A1
• Filed: 06/24/2004
• Published: 12/29/2005
• Est. Priority Date: 06/24/2004
• Status: Active Grant

• Current Assignee: CryoCor Incorporated (Boston Scientific Corporation)
• Original Assignee: CryoCor Incorporated (Boston Scientific Corporation)
• Inventors: Koerner, Richard J., Lentz, David J., O'Donnell, Joseph A., Salinas, Alvin B.
• Granted Patent: US 7,374,553 B2
• Time in Patent Office: Days
• US Class Current: 606/21
• CPC Class Codes: A61B 18/02 by cooling, e.g. cryogenic techniques devices for cooling specific reflex points of the body within cell-life limits A61H39/06
• CPC Class Codes: A61B 2017/003 Steerable
• CPC Class Codes: A61B 2018/0212 using an instrument inserted into a body lumen, e.g. catheter
• CPC Class Codes: A61B 2018/0262 using a circulating cryogenic fluid
• CPC Class Codes: A61M 2025/0161 wherein the distal tips have two or more deflection regions
• CPC Class Codes: A61M 25/0043 characterised by structural features
• CPC Class Codes: A61M 25/0136 Handles therefor
• CPC Class Codes: A61M 25/0138 having flexible regions as a result of weakened outer material, e.g. slots, slits, cuts, joints or coils
• CPC Class Codes: A61M 25/0147 with movable mechanical means, e.g. pull wires

Abstract

A bi-directional system for actively deflecting the distal tip of a catheter includes a reconfigurable tube that is positioned proximal to the catheter'"'"'s distal tip. The tube is formed with slits that are arranged to allow the tube to be transformed from a relaxed, cylindrical configuration to a plurality of deflected configurations. First and second pull wires are provided, with each wire having a respective distal end that is attached to the distal end of the tube. Each wire extends to a catheter handle where it is attached to a respective reel. The reels can be rotated, back and forth, to selectively deflect or relax the tube. To ensure a smooth recovery after a relatively large deflection, a mechanism is disclosed for delaying an application of tension on one of the pull wires until at least a portion of any tension on the other pull wire is released.

Claims

1. A system for steering a catheter through the vasculature of a patient using bi-directional control, said system comprising:

a tubular catheter structure having a proximal end and a distal end;

a clockwise (CW) reel;

a first pull wire having a first end attached to said catheter structure and a second end attached to said CW reel, said first pull wire for deflecting said catheter structure distal end in a first direction in response to a rotation of said CW reel about a rotation axis;

a counterclockwise (CCW) reel;

a second pull wire having a first end attached to said catheter structure and a second end attached to said CCW reel, said second pull wire for deflecting said catheter structure distal end in a second direction in response to a rotation of said CCW reel about the rotation axis, with the second direction being substantially coplanar and opposite to the first direction; and

a means operable on said CW and CCW reels for applying a tension to said first pull wire to deflect said catheter structure distal end in the first direction and thereafter for delaying an application of tension to said second pull wire until at least a portion of said tension on said first pull wire is selectively released to respectively deflect said catheter structure distal end from the first direction to the second direction.

2. A system as recited in claim 1 wherein said tubular catheter structure comprises a tube having a wall formed with a plurality of slits, said tube being transformable between a first, relaxed configuration wherein said tube is substantially cylindrical shaped and a second, deflected configuration.

3. A system as recited in claim 1 wherein said tube is made of a metal.

4. A system as recited in claim 3 wherein said tube wall has an inner wall surface and said system further comprises a guiding means for maintaining said first pull wire along said inner wall during a movement of said first pull wire.

5. A system as recited in claim 4 wherein said guiding means comprises a plurality of indentations, with each indentation formed in said tube wall between a pair of axially adjacent slits, and wherein each indentation forms a passageway for threading said first pull wire therethrough.

6. A system as recited in claim 1 further comprising a catheter handle having a handle housing, and wherein said CW reel is attached to said housing for rotation relative to said housing about the rotation axis in a first rotation direction to pull said first pull wire and a CCW reel attached to said housing for rotation relative to said housing about the rotation axis in a second rotation direction to pull said second pull wire, with said first rotation direction being opposite said second rotation direction.

7. A system as recited in claim 6 wherein said handle further comprises:

a drive cog mounted on said handle housing for rotation about the rotation axis, said drive cog for engaging said CW reel to rotate said CW reel in the first rotation direction;

a turn knob mounted on said handle housing for rotation about the rotation axis, said turn knob for selectively rotating said drive cog about the rotation axis; and

a mechanical means for holding said turn knob in a selected position relative to said handle housing to maintain a preselected tension in said first pull wire.

8. A system as recited in claim 7 wherein said mechanical means comprises a friction washer clamped between said turn knob and said handle housing at a preselected clamping pressure.

9. A system as recited in claim 7 wherein said drive cog is engageable with said CCW reel to rotate said CCW reel in the second rotation direction.

10. A system for bi-directionally deflecting a distal portion of a catheter, said system comprising:

an elongated catheter body having a proximal portion and a distal portion, with the distal portion being formed with a lumen;

a tube disposed in said lumen and having a wall formed with a plurality of slits, said tube having a proximal end and a distal end;

a first pull wire for deflecting the distal end of said tube in a first direction, said first pull wire having a distal end and a proximal end, with the distal end thereof attached to said tube;

a second pull wire for deflecting the distal end of said tube in a second direction, with the second direction being substantially coplanar and opposite to the first direction, said second pull wire having a distal end and a proximal end, with the distal end thereof attached to said tubular structure; and

a means operable on the proximal end of said first pull wire for selectively moving said first pull wire to deflect the distal end of said tube in the first direction, with said means operable on the proximal end of said second pull wire for selectively moving said first pull wire to deflect the distal end of said tube in the second direction.

11. A system as recited in claim 10 wherein said tube wall has an inner wall surface and said system further comprises a guiding means for maintaining said first pull wire along said inner wall during a movement of said first pull wire.

12. A system as recited in claim 11 wherein said guiding means comprises a plurality of indentations, with each indentation formed in said tube wall between a pair of axially adjacent slits, and wherein each indentation forms a passageway for threading said first pull wire therethrough.

13. A system as recited in claim 10 wherein said tube is made of a metal.

14. A system as recited in claim 10 further comprising a catheter handle having a handle housing and wherein said moving means comprises a reel attached to said housing for rotation relative to said housing about a rotation axis, with said proximal end of said first pull wire attached to said reel at a distance from said rotation axis.

15. A system as recited in claim 10 wherein said plurality of slits comprises a plurality of first slits and a plurality of second slits, each first slit having a center and a substantially same arc length, with the plurality of first slits cut into the tube through the wall in planes substantially perpendicular to the axis with their respective centers aligned substantially parallel to the axis, and wherein each second slit has a center and a substantially same arc length, with the plurality of second slits cut into the tube through the wall in planes substantially perpendicular to the axis with their respective centers aligned substantially parallel to the axis;

wherein the centers of the plurality of first slits are azimuthally offset from the centers of the plurality of second slits, and the plurality of first slits are axially offset from adjacent slits in the plurality of second slits.

16. A method for bi-directionally deflecting a distal portion of a catheter, said method comprising the steps of:

providing an elongated catheter body having a proximal portion and a distal portion, with the distal portion being formed with a lumen;

disposing a tube in said lumen, said tube having a wall formed with a plurality of slits, said tube having a proximal end and a distal end;

attaching an end of a first wire to said tube;

affixing an end of a second wire to said tube;

inserting said distal catheter body portion into a body conduit of a patient;

pulling said first wire from an extracorporeal location to deflect the distal end of said tube in a first direction; and

retracting said second wire from an extracorporeal location to deflect the distal end of said tube in a second direction.

17. A method as recited in claim 16 wherein said tube wall has an inner wall surface and said method further comprises the step of maintaining said first wire along said inner wall during said pulling step.

18. A method as recited in claim 16 wherein said pulling step is accomplished using a reel attached to a catheter handle housing for rotation relative to said housing about a rotation axis, with said first wire attached to said reel at a distance from the rotation axis for movement therewith.

19. A method as recited in claim 16 wherein the body conduit is a heart chamber.

20. A method as recited in claim 16 wherein the catheter has a cryo-tip and said method further comprises the step of cooling said cryo-tip to ablate tissue in the body conduit.