Endovascular stent and delivery system

• US 5,314,444 A
• Filed: 04/02/1993
• Issued: 05/24/1994
• Est. Priority Date: 03/13/1987
• Status: Expired due to Term

• Current Assignee: Cook Incorporated (Cook Group Incorporated)
• Original Assignee: Cook Incorporated (Cook Group Incorporated)
• Inventors: Gianturco, Cesare
• Primary Examiner(s): Lewis, Ralph
• Application Number:
  US08/041,946
• Time in Patent Office: 417 Days
• Field of Search: 606/191-200, 604/8, 604/96, 604/104, 623/1, 623/12, 623/900
• US Class Current: 606/195
• CPC Class Codes: A61F 2/885 comprising a coil including a plurality of spiral or helical sections with alternate directions around a central axis
• CPC Class Codes: A61F 2/958 Inflatable balloons for placing stents or stent-grafts
• CPC Class Codes: B21F 45/008 of medical instruments, e.g. stents, corneal rings medical science A61

Abstract

A wire stent for insertion and expansion into a passageway comprises a plurality of curved sections that are formed into a generally circular configuration. Adjacent curved sections are joined by a bend or cusp, so that a series of alternating opposing loops are formed. The wire stent as formed has a cylindrical shape with a longitudinal opening through which a folded balloon catheter is inserted. The opposing loops are tightly contracted about the catheter so that the cylindrical shape has an overlapping region in which portions of adjacent loops longitudinally overlap. The loops are arranged so that when the balloon catheter is inflated, adjacent loops diverge circumferentially relative to each other, thereby decreasing the overlapping region while increasing the diameter of the cylindrical shape. As the diameter of the cylindrical shape increases, the wire stent contacts the surface of a passageway in which the stent is inserted.

In a method of the present invention, the wire stent is fabricated from a wire formed into a planar serpentine configuration. The wire is centered over a semi-cylindrical trough in a flat plate and then pressed into the trough by a forming bar so that a portion of the wire assumes the semi-cylindrical shape. A pulling tool, having a hook at one end, is engaged at the hook with the exposed loops of the serpentine configuration for pulling the exposed loops over the exposed portion of the forming bar to form a generally cylindrical shape from the wire. Once the wire is extracted from the trough and the forming bar is removed, a folded balloon catheter is inserted through the cylindrical shape and the wire is tightly pressed about the catheter.

Claims

1. A stent comprising:

a malleable wire formed into a serpentine pattern including a plurality of wire segments joined in a series by a plurality of bends;

said serpentine pattern being wrapped about a longitudinal axis to define a hollow cylinder;

said hollow cylinder having a first diameter and at least a portion of said hollow cylinder being inelastically deformable from said first diameter to a second expanded diameter; and

means, disposed within said hollow cylinder, for inelastically expanding said portion from said first diameter to said second expanded diameter.

2. The stent of claim 1 wherein said means for expanding is a balloon catheter.

3. The stent of claim 2 having a length defined by said serpentine pattern along said longitudinal axis and wherein the stent includes means for maintaining said length substantially constant when said stent is expanded from said first diameter to said second expanded diameter.

4. The stent of claim 3, wherein said means for maintaining said length includes said plurality of wire segments oriented substantially perpendicular to said longitudinal axis between said bends.

5. The stent of claim 2 wherein said bends are U-shaped bends.

6. The stent of claim 5 wherein successive U-shaped bends open in alternating directions.

7. The stent of claim 6 wherein the stent has a longitudinal axis and said U-shaped bends are distributed substantially uniformly along said longitudinal axis.

8. The stent of claim 7 wherein the stent is longitudinally flexible relative to a curved body passageway such that said longitudinal axis assumes a curved shape when positioned in a curved body passageway.