Controlled deformation of a polymer tube with a restraining surface in fabricating a medical article

• US 8,043,553 B1
• Filed: 09/30/2004
• Issued: 10/25/2011
• Est. Priority Date: 09/30/2004
• Status: Active Grant

• Current Assignee: Advanced Cardiovascular Systems Incorporated
• Original Assignee: Advanced Cardiovascular Systems Incorporated
• Inventors: Durcan, Jonathan P.
• Primary Examiner(s): Huson; Monica
• Assistant Examiner(s): PIERY, MICHAEL T
• Application Number:
  US10/956,759
• Time in Patent Office: 2,581 Days
• Field of Search: 264/573, 264/249, 264/532, 264/570, 264/235, 604/96.01
• US Class Current: 264/573
• CPC Class Codes: A61F 2/82 Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95; for closing wounds, or holding wounds closed A61B17/04 - A61B17/115; dilators A61M29/00
• CPC Class Codes: B29C 2043/028 using radial compression
• CPC Class Codes: B29C 2043/3222 pressurized gas, e.g. air
• CPC Class Codes: B29C 2049/4605 containing an inert gas, e.g. helium
• CPC Class Codes: B29C 2049/4608 Nitrogen
• CPC Class Codes: B29C 2049/462 Oxygen
• CPC Class Codes: B29C 2949/08 Preforms made of several individual parts, e.g. by welding or gluing parts together
• CPC Class Codes: B29C 43/10 Isostatic pressing, i.e. using non-rigid pressure-exerting members against rigid parts or dies
• CPC Class Codes: B29C 49/48 Moulds
• CPC Class Codes: B29C 49/56 Opening, closing or clamping means
• CPC Class Codes: B29C 55/24 radial
• CPC Class Codes: B29L 2023/00 Tubular articles B29L2024/00 takes precedence ; catheters B29L2031/7542
• CPC Class Codes: B29L 2031/7542 Catheters
• CPC Class Codes: B29L 2031/7543 Balloon catheters

Abstract

Methods of manufacturing a medical article that include radial deformation of a polymer tube are disclosed. A medical article, such as an implantable medical device or an inflatable member, may be fabricated from a deformed tube.

Claims

1. A method for fabricating an implantable medical device having a final diameter, comprising:

disposing in a cavity a polymer tube having an initial diameter defined by an outer surface thereof, the cavity being formed by sliding wedges having respective abutting surfaces defining an opening of the cavity, the sliding wedges configured for being displaced radially outward when the tube is radially expanded within the cavity;

disposing the abutting surfaces of the sliding wedges at about the outer surface of the tube; and

radially expanding the tube from the initial diameter to the final diameter, wherein the sliding wedges apply a radial restraining force on the expanding tube as the outer surface of the tube contacts the abutting surfaces and displaces the sliding wedges radially outward; and

fabricating the implantable medical device from the expanded tube.

2. The method of claim 1, wherein the polymer comprises a bioabsorbable polymer.

3. The method of claim 1, wherein the tube is deformed axially and radially.

4. The method of claim 1, wherein the tube is radially expanded by increasing a pressure in the tube.

5. The method of claim 4, wherein the pressure is increased by conveying a fluid into the tube.

6. The method of claim 5, wherein the fluid comprises an inert gas comprising air, oxygen, nitrogen, and/or argon.

7. The method of claim 1, wherein a longitudinal axis of the cavity is parallel or approximately parallel to a cylindrical axis of the tube.

8. The method of claim 1, wherein the outer surface is exposed to at least six sliding wedges, each having an abutting surface and the respective at least six abutting surfaces are arranged to form a cavity that approximates a circle.

9. The method of claim 1, wherein a rate of deformation of the tube is slower than a rate of unrestrained deformation of the tube by the restraining force applied to the tube by the sliding wedges.

10. The method of claim 1, wherein a rate of deformation of the tube is controlled to increase a circumferential strength and circumferential modulus of the tube more than an unrestrained deformation of the tube.

11. The method of claim 1, wherein a rate of deformation is controlled to reduce or eliminate axial deformation.

12. The method of claim 1, wherein the radial expansion of the tube increases the radial strength and modulus of the tube.

13. The method of claim 1, further comprising heating the tube prior to, contemporaneously with, and/or subsequent to radially expanding the tube.

14. The method of claim 1, wherein the tube is heated by heating the abutting surfaces prior to radial expansion of the tube.

15. The method of claim 1, wherein the tube is radially expanded at a temperature greater than or equal to a glass transition temperature of the polymer and less than or equal to a melting temperature of the polymer.

16. The method of claim 1, wherein the cavity is formed by an iris mechanism comprising the sliding wedges.