Longitudinally elongating balloon expandable stent

• US 5,695,516 A
• Filed: 02/21/1996
• Issued: 12/09/1997
• Est. Priority Date: 02/21/1996
• Status: Expired due to Term

• Current Assignee: Isostent, Inc. (Cardinal Health, Inc.)
• Original Assignee: ISO Stent Incorporated
• Inventors: Fischell, David R., Fischell, Robert E., Fischell, Tim A.
• Primary Examiner(s): Buiz, Michael
• Assistant Examiner(s): TRUONG, KEVIN THAO
• Application Number:
  US08/604,682
• Time in Patent Office: 657 Days
• Field of Search: 606/198, 606/191, 606/194, 606/197, 606/195, 606/200, 623/1, 623/12
• US Class Current: 606/194
• 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 2002/91558 connected peak to peak
• CPC Class Codes: A61F 2002/91566 connected trough to trough
• CPC Class Codes: A61F 2250/0067 Means for introducing or releasing pharmaceutical products into the body
• CPC Class Codes: A61F 2310/00131 Tantalum or Ta-based alloys
• CPC Class Codes: A61F 2310/00155 Gold or Au-based alloys

Abstract

The present invention is designed to overcome several disadvantages of prior art balloon expandable stents. Specifically, the Butterfly Expandable To Honeycomb (BETH) stent described herein consists of a collection of circumferential (or vertical) arc structures and diagonal struts. These arcs and struts form a butterfly shape before the stent is expanded and a hexagonal, honeycomb type of structure is created when the stent is fully expanded. Until the nominal stent diameter is reached, the deployed length of the stent is actually longer than the non-deployed length. At the nominal fully-deployed diameter, the deployed stent is exactly the same length as the non-deployed length. This characteristic provides better assurance of completely covering a dilated stenosis as compared to a stent that shortens in length when deployed as is typical of all prior art balloon expandable stents. Furthermore, because at least one quarter of the expanded stent'"'"'s circumference consist of vertical arcs that are arcs of a circle, they provide the BETH stent with improved radial rigidity.

Claims

1. A cylindrical stent for placement in a vessel of a human body, the stent having a longitudinal axis and also having circumferential arcs and diagonal struts with the intersection angle between the circumferential arcs and the diagonal struts being within the range of 10 to 80 degrees when the stent is in its non-deployed state, the diagonal struts being joined by curved sections to the circumferential arcs which collectively form a closed perimeter cell, the closed perimeter cell having two parallel, circumferential arcs located at the longitudinal extremities of the closed perimeter cell and the circumferential arcs lying generally perpendicular to the stent'"'"'s longitudinal axis.

2. The stent of claim 1 wherein the width of the circumferential arcs is greater than the width of the diagonal struts.

3. The stent of claim 1 wherein the stent is formed from stainless steel.

4. The stent of claim 1 wherein the stent is formed from tantalum.

5. The stent of claim 1 wherein the stent is constructed of a metal that is coated with a high density, radiopaque metal.

6. The stent of claim 5 wherein the metal is gold.

7. The stent of claim 1 wherein the stent is coated with an anti-thrombogenic coating.

8. The stent of claim 1 wherein the stent includes a radioisotope material to prevent neointimal hyperplasia subsequent to balloon angioplasty.

9. A cylindrical stent for implantation into a vessel of a human body, the stent being adapted to lengthen longitudinally as its diameter increases from its non-deployed diameter, the stent structure to accomplish lengthening including a multiplicity of closed perimeter cells each cell including within its perimeter at least two diagonal struts, which diagonal struts increase their projected length in the longitudinal direction as the stent diameter is increased from its non-deployed diameter.

10. The stent of claim 9 wherein the stent is constructed of a metal that is coated with a high density, radiopaque metal.

11. The stent of claim 10 wherein the metal is gold.

12. The stent of claim 9 wherein the stent is coated with an anti-thrombogenic coating.

13. The stent of claim 9 wherein the stent includes a radioisotope material to prevent neointimal hyperplasia subsequent to balloon angioplasty.

14. A stent in the form of a thin-walled cylinder having a longitudinal axis, the stent having a multiplicity of hexagonal cells that form a honeycomb type cylindrical structure, each side of each hexagonal cell being approximately equal in length to every other side and each hexagonal cell having a first circumferential arc located at one longitudinal extremity of the hexagonal cell and a second circumferential arc located at the opposite longitudinal extremity of the hexagonal cell, the first and second circumferential arcs being generally parallel to each other and each circumferential arc lying generally perpendicular to the stent'"'"'s longitudinal axis.

15. The stent of claim 14 wherein the width of the circumferential arcs is greater than the width of the diagonal struts.

16. The stent of claim 14 wherein the stent has curved sections that join the circumferential arcs to the diagonal struts.

17. The stent of claim 16 wherein the curved sections have a narrower width as compared to the diagonal struts.

18. The stent of claim 14 wherein the stent includes a radioisotope material to prevent neointimal hyperplasia subsequent to balloon angioplasty.