Method for making a balloon catheter stent deployment system

• US 6,289,568 B1
• Filed: 11/16/1998
• Issued: 09/18/2001
• Est. Priority Date: 11/16/1998
• Status: Expired due to Term

• Current Assignee: Cardinal Health Switzerland 515 GmbH (Cardinal Health, Inc.)
• Original Assignee: Cordis Corporation (Cardinal Health, Inc.)
• Inventors: Miller, Jay F., Play, Edward J.
• Primary Examiner(s): Hughes, S. Thomas
• Assistant Examiner(s): Cozart, Jermie E.
• Application Number:
  US09/192,899
• Time in Patent Office: 1,037 Days
• Field of Search: 295/05, 295/16, 294/23, 606/108, 606/198, 623/1.11, 623/1.15, 623/1.2, 623/1.23
• US Class Current: 29/423
• CPC Class Codes: A61F 2/958 Inflatable balloons for placing stents or stent-grafts
• CPC Class Codes: A61M 25/0014 Connecting a tube to a hub
• CPC Class Codes: Y10T 29/4981 Utilizing transitory attached element or associated separate material
• CPC Class Codes: Y10T 29/49927 Hollow body is axially joined cup or tube

Abstract

A balloon catheter and stent delivery system for medical treatment of a patient includes a balloon inflatable to an inflated shape having a cylindrical working portion, and a deflated shape that is temporarily reformed to enhance longitudinal retention of the stent while the catheter system is advanced or withdrawn. The balloon catheter provides for uniform expansion of the stent when the balloon is inflated. In addition, the balloon catheter system can be modified to initiate partial inflation of the proximal and distal ends of the stent, to further resist longitudinal motion of the stent during inflation, and to facilitate more effective tacking of the stent. One possible feature of the catheter system is that the balloon is pleated in a particular pattern when deflated, whereby the central balloon portion carrying the stent has a greater number of pleats than the shoulder portions proximal and distal of the stent. Another possible feature is the formation of small channels that facilitate fluid communication from the proximal end of the balloon to the distal end, even when the balloon is deflated. The balloon may be formed to protrude partially outward among the stent interstices while in its deflated state, further enhancing stent position retention. The present invention also protects the leading or distal end of the stent during advancement, and protects the proximal end of the stent during any withdrawal of the catheter system.

Claims

1. A method for making a balloon catheter stent deployment system, comprising the steps of:

providing a balloon catheter with an elongated flexible shaft having proximal and distal ends, a hub affixed to the shaft proximal end and having an inflation port, and an inflatable balloon affixed to the shaft near the shaft distal end;

the shaft defining an inflation lumen providing fluid communication of an inflation fluid between the hub inflation port and the balloon, such that the balloon is adapted for selective inflation from a deflated state to an inflated state, as well as later deflation;

the balloon being formed of a substantially inelastic material;

the balloon having a cylindrical working portion with an inflated cross-sectional area located between a pair of conical portions and a pair of leg portions when the balloon is in the inflated state;

pleating the balloon in a deflated state into multiple longitudinal pleats and wrapping the pleats around a portion of the shaft;

providing a cylindrical phantom stent defining a tubular wall thickness;

mounting the phantom stent around the balloon;

inserting the balloon and phantom stent into a tubular mold defining a single inner diameter throughout its working length;

pressurizing the balloon with a pressurized fluid to a first pressure, and simultaneously heating the balloon, phantom stent and mold;

thereby causing the balloon to form a first and second shoulder located immediately proximal and distal of the phantom stent;

each balloon shoulder having an initial outer diameter equal to the initial outer diameter of the phantom stent;

such that the balloon defines an indented nest shape for the stent in the deflated state;

removing the balloon and phantom stent from the mold;

removing the phantom stent from the balloon catheter; and

providing a cylindrical medical stent having a wall thickness less than the phantom stent wall thickness;

sliding the medical stent over the balloon and crimping the medical stent around the balloon;

such that the balloon shoulders have an outer diameter greater than an outer diameter of the crimped medical stent;

wherein the balloon is temporarily reformed into a modified shape, and is adapted to inflate and expand the stent to a deployed larger diameter, whereby the balloon forms said cylindrical working portion at above a preselected transition pressure, such that the cylindrical working portion and the portions defining the balloon shoulders in the deflated state have substantially the same diameter in the inflated state;

thereby causing said indented nest shape to substantially disappear.

2. The method of claim 1, wherein the phantom stent is made of a polymer material, and the medical stent is metal.

3. The method of claim 1, wherein the phantom stent has a cut extending from a proximal end to a distal end of the phantom stent, for facilitating removal of the phantom stent from the balloon.

4. The method of claim 1, wherein the phantom stent and the medical stent have equal lengths, such that after the step of crimping, the balloon shoulders are located immediately proximal and distal of the medical stent.