Method of fabricating a biaxially oriented implantable medical device

• US 7,875,233 B2
• Filed: 07/18/2005
• Issued: 01/25/2011
• Est. Priority Date: 09/30/2004
• Status: Expired due to Fees

• Current Assignee: Advanced Cardiovascular Systems Incorporated (Abbott Laboratories)
• Original Assignee: Advanced Cardiovascular Systems Incorporated (Abbott Laboratories)
• Inventors: Gale, David C., Huang, Bin
• Primary Examiner(s): HUSON, MONICA ANNE
• Application Number:
  US11/184,130
• Publication Number:
  US 20060076708A1
• Time in Patent Office: 2,017 Days
• Field of Search: 264/573, 264/291, 264/482
• US Class Current: 264/512
• CPC Class Codes: A61F 2/91 made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
• CPC Class Codes: A61F 2/915 with bands having a meander structure, adjacent bands being connected to each other
• CPC Class Codes: A61F 2002/91533 characterised by the phase between adjacent bands
• CPC Class Codes: A61F 2230/0013 Horseshoe-shaped, e.g. crescent-shaped, C-shaped, U-shaped
• CPC Class Codes: A61L 31/14 Materials characterised by their function or physical properties , e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
• CPC Class Codes: B23K 2103/42 Plastics B23K2103/16 takes precedence
• CPC Class Codes: B23K 2103/50 Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26

Abstract

Methods of manufacturing a radially expandable stent, including radial expansion and axial elongation of a polymer tube, are disclosed.

Claims

1. A method for fabricating a stent having increased strength, comprising:

providing a first polymeric tube having a cylindrical axis;

providing a stent pattern defining an orientation and shape of a bending portion of a stent strut relative to the cylindrical axis;

applying a radial pressure and axial tension to the tube, including the steps of

raising the temperature of the tube to above the glass transition temperature of the tube, and while at the raised temperature

expanding the tube including simultaneously applying the axial tension and radial pressure to the tube according to a selected axial and radial draw ratio, respectively, wherein the axial and radial draw ratios are selected to cause polymer chains to align with the direction of stress and strain for the bending portion,

after expanding the tube, cooling the tube to a temperature below the glass transition temperature while maintaining the applied pressure and tension to the tube;

forming the stent from the deformed tube according to the stent pattern;

crimping the stent to create a crimped state of the stent and then examining the stent'"'"'s mechanical properties when in the crimped state;

deploying the stent from the crimped state to a deployed state and then examining the stent'"'"'s mechanical properties in the deployed state;

selecting a new axial and radial draw ratio;

providing a second polymeric tube having a cylindrical axis; and

repeating the applying, forming, crimping and deploying step using the second tube and the new axial and radial draw ratio.

2. The method of claim 1, wherein the tube comprises a biostable and/or bioabsorbable polymer.

3. The method of claim 1, wherein the tube is deformed radially by applying a radial pressure.

4. The method of claim 3, wherein applying radial pressure comprises conveying a gas at a selected pressure into the tube.

5. The method of claim 1, wherein the tube is deformed axially by applying a tensile force along the cylindrical axis.