Kink-resistant stent devices and related methods
A device includes an elastic tubular stent including struts forming closed cells arranged in rows along a circumferential direction of the stent, with each cell having a first obtuse-angled corner on one end of the cell along a longitudinal direction of the stent and a second obtuse-angled corner on an opposing end of the cell along the longitudinal direction. The stent may be fabricated by cutting an array of quadrilateral cells in a nitinol hypotube to form a stent, with each cell having four corners with approximately equal angles. The stent may then be expanded radially such that each cell has a first obtuse-angled corner on one end of the cell along a longitudinal direction of the stent and a second obtuse-angled corner on an opposing end of the cell along the longitudinal direction, and heat treated to fix the shape of the stent.
1. A device comprising:
a self-expanding tubular stent extending in a longitudinal direction, the self-expanding tubular stent comprising:
a plurality of struts forming a plurality of closed cells arranged in rows around the self-expanding tubular stent in a circumferential direction,
wherein each of the rows comprises two to four closed cells, and wherein the closed cells of at least one of the rows are substantially equilateral cells, and
wherein, in an expanded state, each of the closed cells has a width in the circumferential direction greater than a length in the longitudinal direction, and has a longitudinal angle that is obtuse and a circumferential angle that is acute.
2. The device of claim 1 , wherein a ratio of the width to the length is between 1.5 and 3.
3. The device of claim 1 , wherein the stent is formed from a nitinol hypotube.
4. The device of claim 1 , wherein each of the rows comprises an equal number of the closed cells.
5. The device of claim 1 , wherein each of the rows comprises four of the closed cells.
6. The device of claim 1 , wherein of the rows comprises three of the closed cells.
7. The device of claim 1 , wherein each of the rows comprises two of the closed cells.
8. The device of claim 1 , wherein each of the rows comprises a different number of the closed cells.
9. The device of claim 1 , wherein the stent is configured to be crimped to a smaller diameter, such that an outward radial force is stored when crimped.
10. The device of claim 1 , wherein one or more of the struts at one or both end regions of the stent in the longitudinal direction are flared.
11. The device of claim 1 , wherein the stent further comprises a plurality of solder holes disposed at one or more struts at one or both end regions of the stent in the longitudinal direction.
12. The device of claim 11 , further comprising a thin-film tubular mesh attached to the solder holes by one or more solders.
13. The device of claim 1 , wherein at least some of the struts extend to form long interconnects, and
wherein the closed cells of at least one pair of the rows are connected together via the long interconnects.
14. A method, comprising:
cutting a nitinol hypotube to form a stent with a plurality of quadrilateral cells, the plurality of quadrilateral cells arranged in rows along a circumferential direction of the stent, and wherein the quadrilateral cells in at least one of the rows are substantially equilateral cells;
expanding the stent radially such that widths of the quadrilateral cells in the circumferential direction are greater than lengths of the quadrilateral cells in a longitudinal direction of the nitinol hypotube, and such that longitudinal angles of the quadrilateral cells are obtuse and circumferential angles of the quadrilateral cells are acute; and
annealing the stent to fix a shape of the stent.
15. The method of claim 14 , wherein a ratio of the widths to the lengths is between 1.5 and 3.
16. The method of claim 14 , wherein the cutting comprises cutting the nitinol hypotube to form two, three, or four quadrilateral cells for each row.
17. The method of claim 14 , wherein the cutting comprises cutting the nitinol hypotube to form different number of quadrilateral cells for different rows.
18. The method of claim 14 , wherein the cutting comprises cutting one or both of longitudinal ends of the nitinol hypotube to form flared ends of the stent.
19. The method of claim 14 , further comprising:
placing a nitinol thin-film tubular mesh over the quadrilateral cells of the stent; and
affixing the thin-film tubular mesh to the stent by soldering the thin-film tubular mesh at solder holes of the stent.
20. The method of claim 19 , further comprising: crimping the stent to reduce a diameter of the stent; and storing the stent in a catheter.
21. The method of claim 20 , further comprising deploying the stent from the catheter in a blood vessel.