Stent and method and apparatus for forming and delivering the same

• US 5,746,765 A
• Filed: 05/17/1996
• Issued: 05/05/1998
• Est. Priority Date: 05/01/1992
• Status: Expired due to Fees

• Current Assignee: NMT Medical Incorporated
• Original Assignee: Nitinol Medical Technologies Incorporated
• Inventors: Kleshinski, Stephen J., Rabkin, Dmitry, Simon, Morris A.
• Primary Examiner(s): Buiz, Michael
• Assistant Examiner(s): Mulcare, Nancy Connolly
• Application Number:
  US08/649,289
• Time in Patent Office: 718 Days
• Field of Search: 623/1, 623/12, 606/191-192, 606/195, 606/198, 604/96, 604/104-106, 604/284
• US Class Current: 128/898
• CPC Class Codes: A61F 2/0077 Special surfaces of prostheses, e.g. for improving ingrowth A61F2/30767 takes precedence
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2/95 Instruments specially adapted for placement or removal of stents or stent-grafts
• CPC Class Codes: A61F 2002/8483 Barbs
• CPC Class Codes: A61F 2002/9534 for repositioning of stents
• CPC Class Codes: A61F 2210/0023 operated at different temperatures whilst inside or touching the human body, heated or cooled by external energy source or cold supply
• CPC Class Codes: A61F 2210/009 magnetic
• CPC Class Codes: A61F 2220/0008 Fixation appliances for connecting prostheses to the body
• CPC Class Codes: A61F 2220/0016 with sharp anchoring protrusions, e.g. barbs, pins, spikes
• CPC Class Codes: A61F 2230/0013 Horseshoe-shaped, e.g. crescent-shaped, C-shaped, U-shaped
• CPC Class Codes: A61F 2230/0017 Angular shapes
• CPC Class Codes: A61F 2240/001 Designing or manufacturing processes
• CPC Class Codes: A61F 2250/0018 differing in elasticity, stiffness or compressibility
• CPC Class Codes: Y10S 623/901 Method of manufacturing prosthetic device

Abstract

A stent comprising a wire skeletal frame, the frame being adapted to assume a first condition in which the frame is relatively rigid and substantially tubular in configuration and a second condition in which the frame is flexible, of reduced stress, and collapsible, such that in the second condition walls of the frame are adapted to be positioned against each other to form a stent diameter substantially equal to the combined thickness of the frame walls in abutting engagement with each other, the frame in its second condition being substantially devoid of bias therein urging the frame to assume the first configuration.

Claims

1. A method for forming a stent from an elongate strand of a metallic thermal shape memory material having a longitudinal axis, said material including martensite variants and/or a metallic grain structure, said method including the steps of:

magnetically orienting said martensite variants at an angle to the longitudinal axis of said elongate strand;

forming a plurality of open cells from said elongate strand by placing said elongate strand on a cell forming mandrel to form said open cells and, subsequently joining said open cells by welding on said mandrel.

2. The method of claim 1 which includes magnetically orienting said metallic grain structure at an angle to the longitudinal axis of said elongate strand before forming a plurality of cells from said elongate strand.

4. The method of claim 1 which includes forming a plurality of adjacent open cells which extend completely around said mandrel, each such cell being formed with two spaced, substantially parallel sidewalls arranged to extend substantially parallel to the longitudinal axis of said mandrel and joining said cells only along the sidewalls of adjacent cells.

3. A method for forming a stent from an elongate strand of a metallic thermal shape memory material having a longitudinal axis, said material including a metallic grain structure, said method including the steps of:

magnetically orienting said metallic grain structure at an angle to the longitudinal axis of said elongate strand;

forming a plurality of open cells from said elongate strand by placing said elongate strand on a cell forming mandrel to form said open cells and,

subsequently joining said open cells by welding on said mandrel.

5. The method of claim 3 which includes forming a plurality of adjacent open cells which extend completely around said mandrel, each such cell being formed with two spaced, substantially parallel sidewalls arranged to extend substantially parallel to the longitudinal axis of said mandrel and joining said cells only along the sidewalls of adjacent cells.