Temporal Intraluminal Stent, Methods of Making and Using

• US 20080103584A1
• Filed: 03/29/2007
• Published: 05/01/2008
• Est. Priority Date: 10/25/2006
• Status: Abandoned Application

• Current Assignee: Biosensors International Group, Ltd.
• Original Assignee: Biosensors International Group, Ltd.
• Inventors: Dutta, Debashis, Shulze, John E., Su, Shih-Horng
• Application Number:
  US11/693,684
• Publication Number:
  US 20080103584A1
• Time in Patent Office: Days
• US Class Current: 623/1.16
• CPC Class Codes: A61F 2/86 Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2/88 the wire-like elements formed as helical or spiral coils forming a net-like or mesh-like structure A61F2/90
• 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 2002/828 Means for connecting a plurality of stents allowing flexibility of the whole structure
• CPC Class Codes: A61F 2002/91525 within the whole structure different bands showing different meander characteristics, e.g. frequency or amplitude
• CPC Class Codes: A61F 2002/91541 Adjacent bands are arranged out of phase
• CPC Class Codes: A61F 2002/91558 connected peak to peak
• CPC Class Codes: A61F 2002/91566 connected trough to trough
• CPC Class Codes: A61F 2002/91591 Locking connectors, e.g. using male-female connections
• CPC Class Codes: A61F 2210/0076 multilayered, e.g. laminated structures
• CPC Class Codes: B29C 41/14 Dipping a core B29C41/10 takes precedence
• CPC Class Codes: B29C 41/34 Component parts, details or accessories; Auxiliary operations
• CPC Class Codes: B29K 2067/046 PLA, i.e. polylactic acid or polylactide

Abstract

A biodegradable polymer stent with radiopacity and a method of making and using a stent with enhanced mechanical strength and/or controlled degradation for use in a bodily lumen is described.

Claims

1. A polymer stent comprising:

a tubular structure formed of a polymer and including an iodinated contrast agent, said structure comprising one or more strength modules comprising one or more radially expandable tubular elements, said strength modules being interconnected by one or more axial linking elements for stent flexibility, wherein said tubular structure is radially expandable between at least an unexpanded diameter and an expanded diameter, and

wherein at least one of the strength modules has a locking mechanism comprising a first and a second locking member, said first locking member being fixedly attached at a valley of the tubular element and said second locking member being fixedly attached at the valley of the tubular element, wherein said first and second locking members are located opposite each other on radially expandable tubular elements such that said first and second locking members are not interlocked with one another when said tubular structure is in the unexpanded diameter and said first and second locking members are interlocked with one another when said tubular structure is in said expanded diameter, whereby the tubular structure is locked at said expanded diameter.

2. The polymer stent of claim 1, wherein said first and second locking members interlock by means of teeth or barbs.

3. The polymer stent of claim 1 wherein said tubular structure is radially expandable between said unexpanded diameter and two or more discrete expanded diameters, wherein said tubular structure is lockable at any of said two or more expanded diameters.

4. The polymer stent of claim 1 wherein said tubular structure is irreversibly expandable from said unexpanded diameter to said expanded diameter.

5. The polymer stent of claim 1, wherein said stent is formed of a polymer selected from the group consisting of biodegradable, bioabsorbable, and bioerodible polymers.

6. The polymer stent of claim 1, further including at least one pharmaceutical agent incorporated in the polymer and which is released from the polymer.

7. The polymer stent of claim 1, wherein said iodinated contrast agent is applied as a coating at least abluminally.

8. The polymer stent of claim 1 wherein said radially expandable tubular elements comprises at least one strut forming a substantially sinusoidal wave structure.

9. The polymer stent of claim 8, wherein said sinusoidal wave structure has more than one peak per circumference.

10. The polymer stent of claim 1, further comprising:

the strength module having at least two circumferential restraint bands facing opposite of a crown valley of the expandable tubular elements, said expandable tubular elements having four or fewer crown peaks, wherein the length of the circumferential restraint band defines a size of the stent when deployed and a length of each circumferential restraint band is less than a length of the expandable tubular elements.

11. A method of making a polymer stent with enhanced mechanical strength comprising the steps of:

a.) dip-coating a mandrel with a solution comprising one or more biocompatible polymers to form a polymer tube at least one of the polymers including an iodinated contrast agent;

b.) spin-drying the polymer tube around its longitudinal axis;

c.) solvent-polishing and vacuum drying the polymer tube;

d.) repeating steps a-c until the polymer tube reaches a desired thickness;

e.) necking the polymer tube by drawing the mandrel bearing the polymer tube through one or more necking dies of decreasing diameter, wherein said necking is carried out at a temperature above the glass transition temperature of the polymer and below the melting temperature of the polymer;

f.) annealing the polymer tube with an inert gas;

g.) removing the polymer tube from the mandrel; and

h.) creating a design in said polymer tube.

12. The method of claim 11, wherein said design is created by laser cutting said polymer tube.

13. The method of claim 11, wherein the solution comprising one or more biocompatible polymers also comprises one or more active pharmaceutical ingredients.

14. The method of claim 11, wherein the solution comprising one or more biocompatible polymers is used in all repetitions of the dip-coating step.

15. The method of claim 11, wherein said solution comprising one or more biocompatible polymers comprises at least two solutions and said repeating step comprises dip-coating the mandrel in a different solution in each repetition.

16. A polymeric stent, comprising:

a plurality of central lobes of approximately the same size arranged in succession at spaced intervals longitudinally defining a stent axis, there being a leading end and a trailing end for each central lobe, the trailing end of each central lobe, other than the last in the succession, being connected to the leading end of the next successive central lobe;

a plurality of peripheral lobes adjoining each central lobe regularly spaced circumferentially about each respective central lobe, there being a leading peripheral lobe and a trailing peripheral lobe for each central lobe, each leading peripheral lobe adjoining the leading end of its corresponding central lobe, each trailing peripheral lobe adjoining the trailing end of its corresponding central lobe; and

a plurality of longitudinal rods attached to the central lobes at one or more points around the periphery of the stent;

wherein said at least a portion of at least one of the central lobes, peripheral lobes, and longitudinal rods are formed of a polymer including an iodinated contrast agent.

17. The polymer stent of claim 16, where in the central lobes and peripheral lobes are formed of a continuous polymeric fiber.

19. The polymer stent of claim 17, wherein the polymeric fiber has a single-fiber construction.

20. The polymer stent of claim 17, where the polymeric fiber has a multiple-fiber ply construction.

21. The polymer stent of claim 17, wherein the polymeric material of the fiber is selected from the group consisting of bioresorbable, bioabsorbable, and bioerodible.

23. The polymer stent of claim 17, wherein the polymeric fiber cord is impregnated with one or more active pharmaceutical ingredients adapted to be released over time in a controlled manner into adjacent tissue when the stent is implanted in a host patient.

24. The polymer stent of claim 16, wherein the stent has a furled small-diameter state and an expanded large diameter state, and wherein the peripheral lobes are only present in the furled small-diameter state having been merged into the central lobes during expansion to the large-diameter state.

25. The polymer stent of claim 24, wherein the peripheral lobes are disposed exterior to the central lobes in the furled small diameter state.

26. The polymer stent of claim 24, wherein the peripheral lobes are confined within the central lobes in the furled small diameter state.

27. The polymer stent of claim 17, wherein at least a portion of the fiber includes an exterior coating that carries one or more active pharmaceutical ingredients.

28. The polymer stent of claim 17, wherein the fiber generally defines a helix in the expanded state.

18. The polymer stent of claim 18, wherein the polymeric fiber is made by thermal extrusion.

29. A method of delivering a non-metallic stent to a vessel lumen of a host, comprising;

providing a continuous cord of non-metallic material and including an iodinated contrast agent;

winding the cord to define an elongated stent having multiple successive coils, each coil having a central lobe and a plurality of peripheral lobes;

attaching at least one longitudinal support element to the stent at circumferentially spaced intervals, the longitudinal support elements extending along the length of the stent;

inserting a balloon into the stent;

positioning the stent at an implant site;

expanding the balloon to expand the stent while employing the peripheral lobes to add circumferential length to the central lobes, thus increasing the diameter of the stent;

collapsing the balloon; and

withdrawing the balloon to leave the stent in place at the implant site.

22. The polymer stent of claim 30, wherein the polymeric material of the fiber comprises Poly-L-lactide (PLLA).

30. The method of claim 29, further comprising delivering at least one therapeutic agent to host tissue adjacent to the stent from agents impregnated in the stent in a time controlled manner.