Microcatheter

• US 6,306,124 B1
• Filed: 02/24/2000
• Issued: 10/23/2001
• Est. Priority Date: 11/13/1995
• Status: Expired due to Term

• Current Assignee: Micro Therapeutics, Inc. (Medtronic Plc)
• Original Assignee: Micro Therapeutics, Inc. (Medtronic Plc)
• Inventors: Jones, Michael L., Evans, Scott, Wallace, George B.
• Primary Examiner(s): NGUYEN, ANH TUAN TUONG
• Application Number:
  US09/512,270
• Time in Patent Office: 607 Days
• Field of Search: 604/507-509, 604/99.02, 604/99.03, 604/99.04, 604/103.09, 604/167-1-1, 604/247, 604/256, 604/532, 128/898
• US Class Current: 604/509
• CPC Class Codes: A61M 2025/0042 Microcatheters, cannula or the like having outside diameters around 1 mm or less
• CPC Class Codes: A61M 25/0012 with embedded structures, e.g. coils, braids, meshes, strands or radiopaque coils
• 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 25/0051 made from fenestrated or weakened tubing layer
• CPC Class Codes: A61M 25/0053 having a variable stiffness along the longitudinal axis, e.g. by varying the pitch of the coil or braid
• CPC Class Codes: A61M 25/0054 with regions for increasing flexibility
• CPC Class Codes: A61M 25/007 Side holes, e.g. their profiles or arrangements; Provisions to keep side holes unblocked
• CPC Class Codes: A61M 25/0075 Valve means

Abstract

Disclosed is an elongate flexible microcatheter, for diagnostic and or therapeutic applications. The microcatheter is provided with a small outside diameter and high degree of flexibility, to facilitate negotiation of small, tortuous vessels such as those encountered in intercranial catheterizations. The catheter is formed from a composite of a series of tubular elements, each extending axially for a different distance along the tubular body. A distal section on one or more of the tubular components is provided with a spiral cut, to modify the flexibility properties of the finished catheter. The catheter may also be provided with an inflatable balloon, and a valve to permit the use of a single lumen for both receiving a guidewire and for conveying inflation media.

Claims

1. A method of treating a vessel, comprising the steps of:

providing a catheter having an elongate flexible tubular body having a central lumen extending axially therethrough, a distal valve within the central lumen, and an inflatable balloon on the distal end of the tubular body in fluid communication with said central lumen proximally of said valve;

advancing a guidewire through the central lumen and through the valve;

positioning the guidewire end catheter within the vessel such that balloon is at a treatment site;

withdrawing the wire from the central lumen; and

thereafter introducing inflation media into the central lumen to inflate the balloon;

wherein the valve moves into a closed position following removal of the guidewire from the central lumen to substantially prevent escape of inflation media through the valve.

2. A method as in Claim 1, wherein the elongate flexible tubular body has a first tubular element in the wall extending axially through the body and terminating in a first distal zone;

a second tubular element in the wall extending axially through the body and terminating in a second distal zone;

the first tubular element being disposed coaxially within the second tubular element; and

each of the first and second tubular elements being provided with a spiral cut in each of the first and second distal zones.

3. A method as in claim 2, wherein the second distal zone in the catheter is axially displaced form the first distal zone.

4. A method as in claim 2, wherein the catheter further comprising a spring coil coaxially disposed within the tubular wall.

5. A method as in claim 4, wherein the spring coil is coaxially disposed on the radially exterior side of the first tubular element and on the radially interior side of the second tubular element.

6. A method as in claim 5, wherein the catheter further comprising an outer tubular jacket surrounding the tubular wall.

7. A method as in claim 6, wherein the catheter further comprising a radiopaque marker disposed proximate the distal end thereof.

8. A method as in claim 2, wherein said first tubular element comprises polytetrafluoroethylene and said second tubular element comprises polyimide.

9. A method as in claim 4, wherein the spring coil comprises a proximal zone in which adjacent windings of coil are positioned in contact with each other, and a distal section in which adjacent windings of coil are spaced axially apart from each other.

10. A method as in claim 4, wherein the spring coil comprises wire having a rectangular cross sectional configuration.

11. A method as in claim 1, wherein the catheter has at least one flexibility gradient zone on the catheter body, said flexibility gradient zone having a first flexibility at a proximal end thereof, a second flexibility at a distal end thereof, and a continuous change in flexibility along the length of the zone from the first flexibility to the second flexibility.

12. A method as in claim 11, wherein said flexibility zone extends for at least about 98% of the length of the catheter.

13. A method as in claim 11, wherein said flexibility zone extends for at least about 75% of the length of the catheter.

14. A method as in claim 11, wherein said tubular body has a wall thickness between an outside surface of the tubular body and the lumen extending therethrough, and the wall thickness at the proximal end of the flexibility zone is greater than the wall thickness at the distal end of the flexibility zone.

15. A method as in claim 11, wherein said flexibility zone comprises a continuous change in wall thickness from the proximal end to the distal end thereof.

16. A method as in claim 11, wherein said flexibility zone extends for at least about 148 cm, and has a wall thickness within the range of from about 0.009 inches to about 0.012 inches at the proximal end thereof and within the range of from about 0.0005 inches to about 0.002 inches at the distal end thereof.