Bioabsorbable implantable endoprosthesis with reservoir

• US 5,980,564 A
• Filed: 08/01/1997
• Issued: 11/09/1999
• Est. Priority Date: 08/01/1997
• Status: Expired due to Term

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Schneider Electric SE
• Inventors: Stinson, Jonathan S.
• Primary Examiner(s): Yu, Mickey
• Assistant Examiner(s): Nguyen, Dinh X.
• Application Number:
  US08/905,806
• Time in Patent Office: 830 Days
• Field of Search: 623/1, 623/2, 623/11, 623/12, 623/66, 606/191, 606/192, 606/194
• US Class Current: 623/23.7
• CPC Class Codes: A61B 2017/00004 (bio)absorbable, (bio)resorbable, resorptive for implantable prostheses A61F2210/0004
• CPC Class Codes: A61F 2/01 Filters implantable into blood vessels
• CPC Class Codes: A61F 2/24 Heart valves ; Vascular valves, e.g. venous valves; Heart implants, e.g. passive devices for improving the function of the native valve or the heart muscle; Transmyocardial revascularisation [TMR] devices; Valves implantable in the body
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61L 27/18 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 27/58 Materials at least partially resorbable by 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: A61L 31/148 Materials at least partially resorbable by the body
• CPC Class Codes: C08L 67/04 Polyesters derived from hydroxycarboxylic acids, e.g. lactones C08L67/06 takes precedence

Abstract

A bioabsorbable implantable endoprosthesis having elongate elements including hollow, cavity or porous portions adapted to accumulate by-product from the degradation of the bioabsorbable material and shortening the diffusion distance for water absorption and thereby relatively increasing the degradation of the structure.

Claims

1. A bioabsorbable implantable endoprosthesis comprising:

a tubular, radially compressible, axially flexible, and radially self-expandable braided and annealed structure having a diameter in a free state, the structure including from about 10 to about 36 filaments including poly (alpha-hydroxy acid), the structure having a radial force of from about 40 grams to about 300 grams at about one-half diameter, each filament having a tensile strength of from about 20 ksi to about 120 ksi, and a tensile modulus of from about 400,000 psi to about 2,000,000 psi, and an average diameter of from about 0.15 mm to about 0.6 mm, the filaments having a crossing angle of from about 120 degrees to about 150 degrees in a free state, each filament including one or more reservoir portions with an average cross-sectional area greater than about 7.9×

10^-7 mm² and in each filament, the sum of the one or more reservoir portions when empty represents a total volume percentage greater than about 10% of the total filament volume.

2. The bioabsorbable implantable endoprosthesis of claim 1 wherein the sum of the one or more reservoir portions when empty represents a total volume percentage of from about 20% to about 40%.

3. The bioabsorbable implantable endoprosthesis of claim 1 wherein the degradation by-products at least partially collect in the reservoir portions.

4. The bioabsorbable implantable endoprosthesis of claim 1 wherein the degradation by-products in the reservoir portions have an average pH level which decreases over time in vivo.

5. The bioabsorbable implantable endoprosthesis of claim 1 wherein the reservoir portions are hollow, cavity, porous, or combinations thereof.

6. The bioabsorbable implantable endoprosthesis of claim 3 wherein the average pH level in the reservoir is between about 3 and 7.

7. The bioabsorbable implantable endoprosthesis of claim 1 wherein the endoprosthesis substantially degrades in vivo in less than 3 years.

8. The bioabsorbable implantable endoprosthesis of claim 1 wherein the endoprosthesis provides structural integrity to a body lumen for less than 2 years.

9. The bioabsorbable implantable endoprosthesis of claim 1 wherein the filaments are mono-filament, multi-filament, ribbon, suture, thread, fiber, or combinations thereof.

10. The bioabsorbable implantable endoprosthesis of claim 1 wherein the implantable endoprosthesis is a stent, stent-graft, graft, filter, occlusive device, or valve.

11. The bioabsorbable implantable endoprosthesis of claim 1 wherein the filaments gain weight in vivo in an amount of from about 0.1% to about 20% of initial mass prior to losing weight in an amount of from about 0.1% to about 70% of initial mass prior to disintegration.

12. The bioabsorbable implantable endoprosthesis of claim 1 wherein the reservoir portions accumulate the degradation by-product for a predetermined amount of time.

13. The bioabsorbable implantable endoprosthesis of claim 1 wherein the filaments comprise PLLA, PDLA, or combinations thereof and substantially degrade in vivo in from about 1 year to about 2 years.

14. The bioabsorbable implantable endoprosthesis of claim 1 wherein the filaments comprise polylactide, polyglycolide, or combinations thereof and substantially degrade in vivo in from about 3 months to about 1 year.

15. The bioabsorbable implantable endoprosthesis of claim 1 wherein the filaments comprise polyglycolide, polygluconate, polydioxanone, or combinations thereof and substantially degrade in vivo in from about 1 week to about 3 months.

16. The bioabsorbable endoprosthesis of claim 1 wherein the thickness of the filament t, in mm, is equal to about (D/(1.8D+15))±

0.03 mm, where D, in mm, is the free state diameter.

17. The bioabsorbable endoprosthesis of claim 1 wherein the number of filaments, N, is equal to about (D/(0.022D+0.17))±

4 filaments, where D, in mm, is the free state diameter.

18. The bioabsorbable endoprosthesis of claim 1 wherein the endoprosthesis has at least one end of diminishing diameter.

19. The bioabsorbable endoprosthesis of claim 1 wherein the filaments have a tensile modulus of from about 700,000 to about 1,200,000 psi.

20. The bioabsorbable endoprosthesis of claim 1 wherein the endoprosthesis has a braid angle of from about 60 degrees to about 150 degrees when implanted in vivo.

21. The bioabsorbable endoprosthesis of claim 1 wherein the filament further comprises a water absorption diffusion distance of from about 1 micron to about 250 microns.

22. The bioabsorbable implantable endoprosthesis of claim 21 further comprising hollow portions when empty which represent a volume percentage of at least 10 percent, cavity portions when empty which represent a volume percentage of at least 10 percent, and porous portions when empty which represent a volume percentage of at least 10 percent.