Radially expandable polymer prosthesis and method of making same

• US 9,079,354 B2
• Filed: 10/31/2012
• Issued: 07/14/2015
• Est. Priority Date: 05/04/2007
• Status: Active Grant

• Current Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories Incorporated)
• Inventors: Lord, Brenna Hearn, Limon, Timothy A., Perzov, Nicole F.
• Primary Examiner(s): Sweet, Thomas J
• Assistant Examiner(s): Mathew, Seema
• Application Number:
  US13/665,529
• Publication Number:
  US 20130090718A1
• Time in Patent Office: 986 Days
• Field of Search: 623/1.15
• US Class Current: 1/1
• CPC Class Codes: A61F 2/0077 Special surfaces of prostheses, e.g. for improving ingrowth A61F2/30767 takes precedence
• 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: 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 2002/91558 connected peak to peak
• CPC Class Codes: A61F 2002/91566 connected trough to trough
• CPC Class Codes: A61F 2002/91575 connected peak to trough
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2230/0069 cylindrical
• CPC Class Codes: A61F 2250/0067 Means for introducing or releasing pharmaceutical products into the body
• CPC Class Codes: A61L 31/06 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds A61L31/041 takes precedence
• CPC Class Codes: B26D 3/10 Making cuts of other than simple rectilinear form cutting-out B26F
• CPC Class Codes: B26D 7/14 by tensioning the work
• CPC Class Codes: B29C 2793/0009 Cutting out
• CPC Class Codes: B29C 53/02 Bending or folding B29C53/22, B29C53/34, B29C53/36, B29C53/56 take precedence
• CPC Class Codes: B29C 55/24 radial
• CPC Class Codes: B29C 67/0014 for shaping tubes or blown tubular films
• CPC Class Codes: B29L 2031/7534 Cardiovascular protheses
• CPC Class Codes: Y10T 156/1043 Subsequent to assembly
• CPC Class Codes: Y10T 29/49826 Assembling or joining
• CPC Class Codes: Y10T 29/49925 : Inward deformation of aperture or hollow body wall
• CPC Class Codes: Y10T 83/0424 : By stretching

Abstract

Polymeric stents having fracture toughness and resistance to recoil after deployment are disclosed along with methods of manufacturing such stents. Improvements to mechanical characteristics and other improvements may be achieved by having polymer chains within individual stent struts oriented in a direction that is closer to or in line with the axis of the individual stent struts. The struts are connected to each other by hinge elements that are configured to bend during crimping and deployment of the stent. Ring struts form ring structures. A ring structure can have an overall curvilinear length from about 12 mm to about 15 mm.

Claims

1. An endoprosthesis comprising:

a tubular network of struts cut from a radially expanded PLLA polymer tube, the tubular network comprising W-shaped closed cells, each W-shaped closed cell abutting six other W-shaped closed cells, each W-shaped closed cell comprising ring struts, link struts, U-shaped hinge elements, and Y-shaped hinge elements, the ring struts forming a plurality of ring structures, each ring structure connected to another one of the ring structures by at least one link strut, each U-shaped hinge element connecting exactly two ring struts to each other, the U-shaped hinge element being tangent to the two ring struts, each Y-shaped hinge element connecting a link strut to exactly two ring struts,

wherein the tubular network has an outer diameter of about 3.5 mm and is configured to be crimped to an outer diameter of about 1.3 mm and expanded to an outer diameter of about 3.8 mm without substantial damage to the U-shaped hinge elements, and

wherein each ring structure has an overall curvilinear length from about 12 mm to about 15 mm, and the overall curvilinear length for each ring structure is measured along an imaginary curve that runs continuously through the center of the linear ring struts and the hinge elements of the ring structure.

2. The endoprosthesis of claim 1, wherein when the tubular network is at about 3.5 mm in outer diameter, each of the ring struts are at a selected angle relative to a link strut, the selected angle being from about 40 degrees to about 50 degrees.

3. The endoprosthesis of claim 1, wherein when the tubular network is at about 3.5 mm in outer diameter, one of the link struts is connected to a first ring strut and a second ring strut, the first and second ring struts connected to opposite ends of the link strut, the first ring strut oriented at about 40 degrees relative to the link strut, the second ring strut oriented at about 50 degrees relative to the link strut.

4. The endoprosthesis of claim 3, wherein the first ring strut is connected to a first U-shaped hinge element and the second ring strut is connected to a second U-shaped hinge element circumferentially offset from the first U-shaped hinge element when the tubular network is at about 3.5 mm in outer diameter.

5. The endoprosthesis of claim 1, wherein each W-shaped closed cell has a perimeter that includes eight of the ring struts and two of the link struts.

6. The endoprosthesis of claim 1, wherein each W-shaped closed cell has a perimeter that includes four of the U-shaped hinge elements and six of the Y-shaped hinge elements.

7. The endoprosthesis of claim 1, wherein each ring structure is connected to an adjacent ring structure by exactly three of the link struts so as to form a ring structure pair, there being a plurality of ring structure pairs and there being exactly three W-shaped closed cells within each of the ring structure pairs.

8. The endoprosthesis of claim 7, wherein each of the W-shaped closed cells within each ring structure pair has a curvilinear length from about 4 mm to about 5 mm, wherein the curvilinear length of each of the W-shaped closed cells is measured along an imaginary curve that runs continuously through the center of the linear ring struts and the hinge elements at one side of the W-shaped closed cell.

9. The endoprosthesis of claim 8, wherein each of the W-shaped closed cells within each ring structure pair has a curvilinear length of about 4.5 mm.

20. The endoprosthesis of claim 1, wherein each ring structure has an overall curvilinear length of about 13.5 mm.

10. A method of making an endoprosthesis, the method comprising:

cutting a radially expanded PLLA polymer tube to form a tubular network of struts, the tubular network comprising W-shaped closed cells, each W-shaped closed cell abutting six other W-shaped closed cells, each W-shaped closed cell comprising ring struts, link struts, U-shaped hinge elements, and Y-shaped hinge elements, the ring struts forming a plurality of ring structures, each ring structure connected to another one of the ring structures by at least one link strut, each U-shaped hinge element connecting exactly two ring struts to each other, the U-shaped hinge element being tangent to the two ring struts, each Y-shaped hinge element connecting a link strut to exactly two ring struts,

wherein the tubular network has an outer diameter of about 3.5 mm and is configured to be crimped to an outer diameter of about 1.3 mm and expanded to an outer diameter of about 3.8 mm without substantial damage to the U-shaped hinge elements, and

wherein each ring structure has an overall curvilinear length from about 12 mm to about 15 mm, and the overall curvilinear length for each ring structure is measured along an imaginary curve that runs continuously through the center of the linear ring struts and the hinge elements of the ring structure.

11. The method of claim 10, further comprising radially expanding a stock tube of PLLA polymer from an outer diameter of about 1.7 mm to an outer diameter of 3.5 mm in order to form the radially expanded PLLA polymer tube at a temperature above Tg of the PLLA polymer.

12. The method of claim 11, further comprising crimping the tubular network onto a catheter, the crimping comprising reducing the tubular network from an outer diameter of about 3.5 mm to a finished diameter of 1.3 mm.

13. The method of claim 10, wherein when the tubular network is at an outer diameter of 3.5 mm, each of the ring struts are at a selected angle relative to a link strut, the selected angle being from about 40 degrees to about 50 degrees.

14. The method of claim 10, wherein when the tubular network is at about 3.5 mm in outer diameter, one of the link struts is connected to a first ring strut and a second ring strut, the first and second ring struts connected to opposite ends of the link strut, the first ring strut oriented at about 40 degrees relative to the link strut, the second ring strut oriented at about 50 degrees relative to the link strut.

15. The method of claim 14, wherein the first ring strut is connected to a first U-shaped hinge element and the second ring strut is connected to a second U-shaped hinge element circumferentially offset from the first U-shaped hinge element when the tubular network is at about 3.5 mm in outer diameter.

16. The method of claim 10, wherein each W-shaped closed cell has a perimeter that includes eight of the ring struts and two of the link struts.

17. The method of claim 10, wherein each W-shaped closed cell has a perimeter that includes four of the U-shaped hinge elements and six of the Y-shaped hinge elements.

18. The method of claim 10, wherein each ring structure is connected to an adjacent ring structure by exactly three of the link struts so as to form a ring structure pair, there being a plurality of ring structure pairs and there being exactly three W-shaped closed cells within each of the ring structure pairs.

19. The method of claim 18, wherein each of the W-shaped closed cells within each ring structure pair has a curvilinear length from about 4 mm to about 5 mm, wherein the curvilinear length of each of the W-shaped closed cells is measured along an imaginary curve that runs continuously through the center of the linear ring struts and the hinge elements at one side of the W-shaped closed cell.