HYBRID STENT WITH HELICAL CONNECTORS

• US 20110093059A1
• Filed: 10/20/2009
• Published: 04/21/2011
• Est. Priority Date: 10/20/2009
• Status: Active Grant

• Current Assignee: Svelte Medical Systems, Inc.
• Original Assignee: Svelte Medical Systems, Inc.
• Inventors: EASTERBROOK, WILLIAM A. III, FISCHELL, ROBERT E., KALAVALAPALLY, RAJESH, FISCHELL, DAVID R.
• Granted Patent: US 8,114,149 B2
• Time in Patent Office: Days
• US Class Current: 623/1.15
• 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 2002/91541 Adjacent bands are arranged out of phase
• CPC Class Codes: A61F 2002/91575 connected peak to trough
• CPC Class Codes: A61F 2230/0013 Horseshoe-shaped, e.g. crescent-shaped, C-shaped, U-shaped

Abstract

The present invention is a hybrid stent design using half-slot circumferential sets of strut members with short (<1.5 mm) slot length that has minimal fish scaling and excellent stent retention and flexibility. These half-slot circumferential sets of strut members are connected one to the other with helical connectors similar to those of the Palmaz stent. One important difference in the design of the stent of the present invention is that the helical connectors are attached to every other crown (rather than connected to every crown) to further improve stent flexibility. By appropriately varying the strut width of both the connected and unconnected curved crowns to be greater at the center than at their ends, an increased radial strength can be provided for a given maximum strain that is imparted to the stent when it is expanded to its maximum diameter.

Claims

1. A balloon expandable stent in the form of a thin-walled, lace-like, cylindrical tubular structure having a multiplicity of half-slot circumferential sets of strut members;

each circumferential set of strut members comprising a series of alternating straight segments and curved crowns;

each circumferential set of strut members being connected to an adjacent circumferential set of strut members by a set of helical connectors that are connected to every other curved crown of each circumferential set of strut members, the crowns attached to a connector being connected crowns and the crowns that are not connected to a connector being unconnected crowns, each of the curved crowns having a tapered width with the strut width at the center of each crown being greater than the strut width at the ends of each crown where the crown attaches to its adjacent straight segments, each crown having a curved interior surface, the sets of helical connectors having slopes which are either positive or negative as seen in the flat layout view of the stent depending on the location of the helical connector within the stent structure and the circumferential extent for each helical connector being less than 90 degrees.

2. The stent of claim 1 where there is a central circumferential set of strut members which has a half slot length and that central circumferential set of strut members is joined on one side to helical connectors having a negative slope and on its opposite side it is joined to helical connectors having a positive slope.

3. The stent of claim 1 where the shape of each connected crown is different from the shape of each unconnected crown so that both connected and unconnected crowns have approximately the same material strain when the stent is expanded to its maximum rated diameter.

4. The stent of claim 1 where the straight portion of each helical connector as seen in the flat, layout view of the stent is at least 30% smaller in width as compared to the average width of the unconnected crowns of the circumferential sets of strut members.

5. The stent of claim 1 where each helical connector has two parallel edges at least one of which is joined tangentially to an outer curve of a connected crown.

6. The stent of claim 1 where each adjacent circumferential set of strut members is out-of-phase with its adjacent circumferential set of strut members.

7. The stent of claim 1 where each adjacent circumferential set of strut members is in-phase with its adjacent circumferential set of strut members.

8. The stent of claim 1 where the length of the half-slot of the hybrid stent is less than 1.5 mm.

10. The stent of claim 1 where the stent is coated with carbon to decrease the formation of thrombus.

11. The stent of claim 1 where the stent is coated with a porous carbon which contains an anti-restenosis drug that is eluted into the arterial wall after the stent is expanded into a coronary or peripheral artery.

12. The stent of claim 10 where the drug that is eluted is chosen from the group that includes sirolimus, everolimus or any analog of sirolimus.

13. The stent of claim 1 where the stent is coated with a polymer into which an anti-restenosis drug has been placed, the anti-restenosis drug being designed to elute into the arterial wall of an artery into which the stent has been first delivered and then expanded.

14. The stent of claim 13 where the polymer is bioabsorbable.

15. The stent of claim 1 where the number of sets of helical connectors as seen in the flat, layout view of the stent that have a positive slope is equal to the number of sets of helical connectors that have a negative slope.

16. The stent of claim 1 where the number of sets of helical connectors having a positive slope and the number of sets of slated connectors having a negative slope differ by one as seen in a flat, layout view of the stent.

9. The stent of claim 9 where the length of the half-slot of the hybrid stent lies between 0.8 and 1.3 mm.

17. A balloon expandable stent in the form of a thin-walled, lace-like, cylindrical tubular structure having a multiplicity of half-slot circumferential sets of strut members;

each circumferential set of strut members comprising a series of alternating straight segments and connected and unconnected curved crowns;

each circumferential set of strut members being connected to an adjacent circumferential set of strut members by a multiplicity of helical connectors having tangential connections to the outer curves of the connected curved crowns of the adjacent circumferential sets of strut members.

18. The stent of claim 17 where the shape of each connected crown is different from the shape of each unconnected crown so that both connected and unconnected crowns have approximately the same material strain when the stent is expanded to its maximum rated diameter.

19. The stent of claim 17 where the stent is coated with carbon to decrease the formation of thrombus.

20. The stent of claim 17 where the stent is coated with a porous carbon which contains an anti-restenosis drug that is eluted into the arterial wall after the stent is expanded into a coronary or peripheral artery.

21. The stent of claim 20 where the drug that is eluted is chosen from the group that includes sirolimus, everolimus or any analog of sirolimus.

22. The stent of claim 17 where the stent is coated with a polymer into which an anti-restenosis drug has been placed, the anti-restenosis drug being designed to elute into the arterial wall of an artery into which the stent has been first delivered and then expanded.

23. A balloon expandable stent in the form of a thin-walled, lace-like, cylindrical tubular structure with a proximal portion and a distal portion having a multiplicity of circumferential sets of strut members each circumferential set of strut members having a half slot length and being connected to an adjacent circumferential set of strut members by a set of helical connectors, the sets of helical connectors having slopes which are either positive or negative as seen in the flat, layout view of the stent, the direction of the helical connectors being different in the proximal portion of the stent as compared to the distal portion of the stent