Process of making a stent

Patent metadata

Field	Value
Publication number	US-9655710-B2
Application number	US-201414152626-A
Country	US
Kind code	B2
Filing date	Jan 10, 2014
Priority date	Jan 28, 2011
Publication date	May 23, 2017
Grant date	May 23, 2017

Abstract

A stent or other prosthesis may be formed by coating a single continuous wire scaffold with a polymer coating. The polymer coating may consist of layers of electrospun polytetrafluoroethylene (PTFE). Electrospun PTFE of certain porosities may permit endothelial cell growth within the prosthesis.

First claim

The invention claimed is:

1. A method of constructing a stent, the method comprising:
electrospinning a first tube of PTFE onto a rotating mandrel;
heating the first tube to between 360° C. to 400° C.;
applying a scaffolding structure around the first tube after the first tube has been heated;
applying a fluorinated ethylene propylene (FEP) layer around the first tube and the scaffolding structure; and
applying a second tube of porous PTFE around the FEP layer;
applying a compressive wrap around the second tube; and
heat-treating the stent above the melting temperature of FEP but below 325° C. while the compressive wrap is disposed around the second tube;
wherein the first tube of PTFE is an innermost tube of he stent that is configured for contact with bodily fluid.

2. The method of claim 1 , wherein the FEP partially coats fibers of the first and second tubes.

3. The method of claim 1 , wherein the second tube comprises electrospun PTFE formed by a method comprising:
electrospinning the second tube of PTFE onto a rotating mandrel; and
sintering the second tube.

4. The method of claim 1 , wherein electrospinning the first tube of PTFE comprises:
mixing a PTFE dispersion with PEO, wherein the PEO is dissolved in water to form a mixture; and
discharging the mixture from an orifice onto the rotating mandrel.

5. The method of claim 4 , wherein the PEO is dissolved in water to form a mixture before the PEO and water mixture is mixed with the PTFE dispersion.

6. The method of claim 1 , wherein at least one of the first and second tubes of PTFE have an average pore size between about 2 microns and about 8 microns.

7. The method of claim 1 , wherein at least one of the first and second tubes of PTFE have an average pore size between about 3 microns and about 5 microns.

8. The method of claim 1 , wherein at least one of the first and second tubes of PTFE have an average pore size of about 1.5 microns or less.

9. The method of claim 1 , further comprising coupling a cuff adjacent an end of the stent, wherein the cuff is configured to promote rapid cellular ingrowth into the cuff.

10. The method of claim 1 , wherein the FEP layer is substantially impermeable to tissue ingrowth.

11. The method of claim 1 , wherein at least one of the first and second tubes of PTFE is configured to permit tissue growth.

12. The method of claim 1 , wherein all the PTFE in the stent comprises electrospun PTFE.

13. A method of constructing a stent covering, the method comprising:
electrospinning a first tube of PTFE onto a rotating mandrel;
heating the first tube to between 360° C. to 400° C.;
applying a tie layer around the first tube after the first tube has been heated;
applying a second tube of PTFE around the tie layer;
applying a compressive wrap around the second tube; and
heat-treating the stent covering above the melting temperature of the tie layer but below the 325° C. while the compressive wrap is disposed around the second tube;
wherein the first tube of PTFE is an innermost tube of the stent that is configured for contact with bodily fluid.

14. The method of claim 13 , wherein the tie layer comprises fluorinated ethylene propylene (FEP).

15. The method of claim 14 , wherein the second tube of PTFE is formed by a method comprising:
electrospinning the second tube of PTFE onto a rotating mandrel; and
sintering the second tube.

16. The method of claim 13 , wherein electrospinning the first tube of PTFE comprises:
mixing a PTFE dispersion with PEO, wherein the PEO is dissolved in water to form a mixture before the PEO and water mixture is mixed with the PTFE dispersion; and
discharging the mixture from an orifice onto the rotating mandrel.

Assignees

• Merit Medical Systems Inc

Inventors

• Eller Zeke
• Hall John William
• Kellar Robert S
• Simmons Rachel Lynn
• Radford Robert J
• Dolmatch Bart

Classifications

• D01D5/0007

  Electro-spinning (non-woven fabrics produced by electro-spinning D04H1/728) · CPC title

• A61L31/146

  Porous materials, e.g. foams or sponges · CPC title

• A61L31/10

  Macromolecular materials · CPC title

• A61F2002/072

  Encapsulated stents, e.g. wire or whole stent embedded in lining · CPC title

• A61F2/915

  with bands having a meander structure, adjacent bands being connected to each other · CPC title