Thermal processing of polymer scaffolds

Patent metadata

Field	Value
Publication number	US-10278844-B2
Application number	US-201715688486-A
Country	US
Kind code	B2
Filing date	Aug 28, 2017
Priority date	Sep 18, 2014
Publication date	May 7, 2019
Grant date	May 7, 2019

Abstract

Methods are disclosed including thermally processing a scaffold to increase the radial strength of the scaffold when the scaffold is deployed from a crimped state to a deployed state such as a nominal deployment diameter. The thermal processing may further maintain or increase the expansion capability of the scaffold when expanded beyond the nominal diameter.

First claim

What is claimed is:

1. A method of fabricating a scaffold comprising:
providing a scaffold in a fabricated state;
wherein the scaffold has a scaffold pattern including a plurality of undulating rings connected by links and each ring includes crests and bar arms between the crests,
wherein the crests have angles that decrease when the scaffold is crimped and increase when the scaffold is expanded; and
thermally processing the scaffold, wherein after the thermal processing the scaffold has a processed state at room temperature, and
wherein a thickness of the scaffold in the processed state is larger than the thickness in the fabricated state.

2. The method of claim 1 , further comprising crimping the scaffold to a delivery balloon when the scaffold has the processed state.

3. The method of claim 1 , wherein a crest angle of the scaffold in the processed state is larger than the crest angle in the fabricated state.

4. The method of claim 1 , wherein the scaffold is made of a PLA polymer, and the scaffold temperature during the thermal processing is 70 to 90° C. for a duration of 5 to 15 min.

5. The method of claim 1 , further comprising disposing the scaffold over a tubular mandrel prior to the thermal processing, wherein an inner diameter of the scaffold decreases to an outer diameter of the mandrel during the thermal processing.

6. The method of claim 1 , wherein an arc length of the scaffold in the processed state is larger than the arc length in the fabricated state.

7. The method of claim 1 , wherein crest angles are less than 100° in the fabricated state and a processing temperature, duration or amount of decrease of a diameter of the scaffold during the thermal processing, or any combination thereof are selected such that the crest angles are 100° to 150° in the processed state.

8. The method of claim 1 , wherein the thickness is 75 to 100 microns in the fabricated state and increases by 10 to 30% in the processed state.

9. The method of claim 1 , wherein the thermal processing is performed during a coating process.

10. The method of claim 1 , wherein the fabricated state is an as-cut scaffold.

11. The method of claim 1 , wherein a width of a bar arm or link in the processed state is less than the width in the fabricated state.

12. A method, comprising:
making a scaffold from a radially expanded tube, wherein the scaffold has a scaffold pattern including a plurality of undulating rings connected by links, each ring includes crests and each crest defines a crest angle, and bar arms extend between crests;
thermally processing the scaffold, wherein after the thermal processing the scaffold has a processed state at room temperature; and
wherein a width of a bar arm is smaller and a thickness of the strut larger in the processed state than the bar arm's width and thickness respectively, in the fabricated state.

13. The method of claim 12 , wherein the radially expanded tube is made from a tube radially expanded by about 200 to 400%.

14. The method of claim 12 , wherein the scaffold is crimped to a balloon shortly after the thermal processing.

15. A method of fabricating a scaffold comprising:
making a scaffold from the radially expanded tube, wherein the scaffold has a scaffold pattern including a plurality of undulating rings connected by links, each ring includes crests and each crest defines a crest angle, and bar arms extend between crests;
imposing a diametric constraint on the scaffold;
thermally processing the scaffold while the scaffold has the diametric constraint, wherein after the thermal processing the scaffold has a processed state at room temperature; and
wherein before the thermal processing the scaffold has a fabricated stent; and
wherein a thickness of the scaffold in the processed state is larger than the thickness in the fabricated state.

16. The method of claim 15 , wherein the diametric constraint is a mandrel disposed within the bore of the scaffold.

17. The method of claim 15 , wherein crest angles are less than 100° in the fabricated state and a processing temperature, duration or amount of decrease of a diameter of the scaffold during the thermal processing, or any combination thereof are selected such that the crest angles are 100° to 150° in the processed state.

18. The method of claim 15 , wherein the thickness is 75 to 100 microns in the fabricated state and the thickness in the processed state is 10 to 30% higher than the thickness in the fabricated state.

19. The method of claim 15 , wherein the radially expanded tube is made from a tube that is radially expanded by about 200 to 400%.

20. The method of claim 15 , wherein the scaffold is crimped to a balloon shortly after the thermal processing.

Assignees

• Abbott Cardiovascular Systems Inc

Inventors

• Lumauig Rommel
• Pacetti Stephen D
• Ding Ni
• Harrington Joel
• Ma Xiao
• Oberhauser James P
• Mccoy Jill
• Abunassar Chad J
• Eswaran Senthil
• Ta Diem

Classifications

• A61L31/148

  Materials at least partially resorbable by the body · CPC title

• B29C2035/0822

  using IR radiation · CPC title

• A61F2230/0069

  cylindrical · CPC title

• B29L2031/7534

  Cardiovascular protheses · CPC title

• B29C71/0009

  using liquids, e.g. solvents, swelling agents (spectacle cases, e.g. for cleaning contact lenses A45C11/04; disinfecting or sterilising contact lenses A61L12/00, using liquid substances A61L2/20; cleaning involving the use of liquid in general B08B3/00; for hydrating contact lenses B29D11/00067) · CPC title