Stent design with struts of various angles and stiffness

• US 20080221661A1
• Filed: 03/09/2007
• Published: 09/11/2008
• Est. Priority Date: 03/09/2007
• Status: Active Grant

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Inventors: Tischler, Brian, Bidne, Ben
• Granted Patent: US 8,512,392 B2
• Time in Patent Office: Days
• US Class Current: 623/1.15
• CPC Class Codes: A61F 2/915 with bands having a meander structure, adjacent bands being connected to each other
• CPC Class Codes: A61F 2002/91508 the meander having a difference in amplitude along the band
• CPC Class Codes: A61F 2002/91516 the meander having a change in frequency along the band
• CPC Class Codes: A61F 2002/91558 connected peak to peak
• CPC Class Codes: A61F 2002/91575 connected peak to trough
• CPC Class Codes: A61F 2230/0054 V-shaped
• CPC Class Codes: A61F 2250/0018 differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2250/0036 differing in thickness

Abstract

The present invention is directed to stent that has a plurality of axially spaced serpentine bands. Each serpentine band comprises a plurality of struts, wherein adjacent struts are connected to each other forming a plurality of peaks and valleys. The plurality of struts comprise a plurality of adjacent pairs of struts, wherein each adjacent pair of struts comprises a first strut and a second strut and wherein the first and second struts have a first end, a second end and a length and a plurality of interconnecting struts axially connect the serpentine bands. The stent further includes a plurality of connector nodes, wherein a plurality of first and second struts that are associated with a connector node have a greater stiffness than a plurality of struts that are not associated with a connector node.

Claims

1. A stent having a proximal end, a distal end, a longitudinal axis extending through the proximal and distal ends, the stent further comprising:

a plurality of axially spaced serpentine bands, each serpentine band comprising a plurality of struts, wherein adjacent struts are connected to each other forming a plurality of peaks and valleys, wherein the plurality of struts comprise a plurality of adjacent pairs of struts, each adjacent pair of struts comprising a first strut and a second strut, wherein the first and second struts have a first end, a second end and a length,

a plurality of interconnecting struts axially connecting the serpentine bands, and

a plurality of connector nodes, wherein an interconnecting strut and the first ends of a first and second strut of an adjacent pair of struts converge to form each connector node, wherein, within at least one of the serpentine bands, a plurality of first and second struts that are associated with a connector node have a greater stiffness than a plurality of struts that are not associated with a connector node.

2. The stent of claim 1, wherein, within a majority of the serpentine bands, a plurality of first and second struts that are associated with a connector node are stiffer than a plurality of struts that are not associated with a connector node.

3. The stent of claim 1, wherein the plurality of connector nodes comprise a plurality of valley connector nodes, wherein an interconnecting strut and the first ends of a first and second strut of an adjacent pair of struts converge to form each valley connector node and wherein, at a point where the interconnecting strut and the first ends of a first and second strut of an adjacent pair of struts converge, the plurality of valley connector nodes have a circumferential width that is at least the combined width of the interconnecting strut and the first and second struts of the adjacent pair of struts and extend axially to form a peak.

4. The stent of claim 3, wherein a first node valley is formed between the first strut and the interconnecting strut and a second node valley is formed between the second strut and the interconnecting strut, the first and second node valleys each having a bottom center point, wherein the bottom center point of the first node valley is at a point that is between 3/16 and ½

of the length of the first strut from its first end to its second end and the bottom center point of the second node valley is at a point that is between 3/16 and ½

of the length of the second strut from its first end to its second end.

5. The stent of claim 4, wherein the bottom center point of the first node valley is at a point that is between ¼

and 7/16 of the length of the first strut from its first end to its second end and the bottom center point of the second node valley is at a point that is between ¼ and

7/16 of the length of the second strut from its first end to its second end.

6. The stent of claim 4, wherein the bottom center point of the first node valley is at a point that is between ¼

and ⅜

of the length of the first strut from its first end to its second end and the bottom center point of the second node valley is at a point that is between ¼ and

⅜

of the length of the second strut from its first end to its second end.

7. The stent of claim 4, wherein the bottom center point of the first node valley is at a point that is about 5/16 of the length of the first strut from its first end to its second end and the bottom center point of the second node valley is at a point that is about 5/16 of the length of the second strut from its first end to its second end.

8. The stent of claim 3, wherein, within at least one of the serpentine bands, a plurality of first and second struts that are associated with a valley connector node are shorter than a plurality of struts that are not associated with a valley connector node.

9. The stent of claim 3, wherein the valley connector nodes each comprise an outer edge and a peak formed by the juncture of the first and second struts and wherein the outer edge has a constant curvature from the first strut to the second strut.

10. The stent of claim 3, wherein, within each serpentine band, there are a plurality of adjacent pairs of strut that are not associated with a valley connector node between the valley connector nodes in the serpentine band.

11. The stent of claim 3, wherein the stent has an as-cut state, a crimped state and an expanded state, wherein the stent is contractable from the as-cut state to the crimped state and expandable from the crimped state to the expanded state, the stent further comprising a plurality of strut pair opening angles formed by the first and second struts of the adjacent pairs of struts, the plurality of strut pair opening angles comprising a plurality of first opening angles and a plurality of second opening angles, wherein the first and second opening angles all face the same direction relative to the longitudinal axis of the stent and wherein, when the stent is in its as-cut state, the first opening angles are larger than the second opening angles.

12. The stent of claim 11, wherein, when the stent is in its as-cut state, the first opening angles are twice as large as the second opening angles.

13. The stent of claim 11, wherein a plurality of the first opening angles are formed by a strut that is associated with a valley connector node and a strut that is not associated with a valley connector node.

14. The stent of claim 11, wherein, within each serpentine band, there are a plurality of adjacent pairs of strut that are not associated with a valley connector node between the valley connector nodes in the serpentine band.

15. The stent of claim 11, wherein all of the first opening angles are formed by strut pairs that have one strut associated with a valley connector node.

16. The stent of claim 3, wherein a plurality of the interconnecting struts that are associated with a valley connector node are connected to a peak of an adjacent serpentine band.

17. The stent of claim 11, the stent further comprising a plurality of node approach opening angles, each being formed by a strut and an interconnecting strut that are associated with the same valley connector node, wherein, when the stent is in its as-cut state, the node approach opening angles are larger than the second opening angles.

18. The stent of claim 11, wherein, when the stent is in its crimped state, the first opening angles are substantially similar to the second opening angles.

19. The stent of claim 18, wherein, when the stent is in its expanded state, the first opening angles are substantially similar to the second opening angles.

20. The stent of claim 17, wherein, when the stent is in its crimped state, the first opening angles are substantially similar to the second opening angles and substantially similar to the node approach opening angles.

29. The stent of claim 1, wherein, within at least one of the serpentine bands, a plurality of first and second struts that are associated with a connector node are shorter than a plurality of struts that are not associated with a connector node.

30. The stent of claim 29, wherein the plurality of first and second struts that are associated with a connector node are about 75%-90% of the length of the plurality of struts that are not associated with a valley connector node.

31. The stent of claim 29, wherein the plurality of first and second struts that are associated with a connector node are about 75%-85% of the length of the plurality of struts that are not associated with a valley connector node.

32. The stent of claim 1, wherein, within at least one of the serpentine bands, a plurality of first and second struts that are associated with a connector node have a greater girth than a plurality of struts that are not associated with a connector node.

33. The stent of claim 32, wherein, within at least one of the serpentine bands, a plurality of first and second struts that are associated with a connector node have a greater width than a plurality of struts that are not associated with a connector node.

34. The stent of claim 33, wherein the plurality of first and second struts that are associated with a connector node are about 1.2 to 2.5 times the width of the plurality of struts that are not associated with a connector node.

35. The stent of claim 33, wherein the plurality of first and second struts that are associated with a connector node are about 1.4 to 2 times the length of the plurality of struts that are not associated with a connector node.

36. The stent of claim 33, wherein the plurality of first and second struts that are associated with a connector node are about 1.4 to 1.6 times the length of the plurality of struts that are not associated with a connector node.

37. The stent of claim 33, wherein a plurality of first and second struts that are associated with a connector node have a greater width substantially along at least majority of their effective strut lengths than a plurality of struts that are not associated with a connector node.

38. The stent of claim 37, wherein a plurality of first and second struts that are associated with a connector node have a greater width substantially along at least 75% of their effective strut lengths than a plurality of struts that are not associated with a connector node.

39. The stent of claim 38, wherein a plurality of first and second struts that are associated with a connector node have a greater width substantially along at least 75% of their effective strut lengths than a plurality of struts that are not associated with a connector node.

40. The stent of claim 1, wherein, within at least one of the serpentine bands, a plurality of interconnecting struts that are associated with a connector node are longer than a plurality of interconnecting struts that are not associated with a connector node.

41. The stent of claim 29, wherein the plurality of connector nodes are peak connector nodes.

42. The stent of claim 32, wherein the plurality of connector nodes are peak connector nodes.

43. The stent of claim 1, wherein stiffness is measured using finite element analysis or the equation

Stiffness=W³*T/L²

wherein W=strut width, T=wall thickness and L=effective strut length.

44. The stent of claim 1, wherein the plurality of first and second struts that are associated with a connector node are at least 1.2 times as stiff as the plurality of struts that are not associated with a connector node.

45. The stent of claim 1, wherein the plurality of first and second struts that are associated with a connector node are at least 1.5 times as stiff as the plurality of struts that are not associated with a connector node.

46. The stent of claim 1, wherein the plurality of first and second struts that are associated with a connector node are at least 2 times as stiff as the plurality of struts that are not associated with a connector node.

47. The stent of claim 1, wherein the plurality of first and second struts that are associated with a connector node are at least 2.5 times as stiff as the plurality of struts that are not associated with a connector node.

48. A stent delivery system comprising a catheter having a distal portion and a stent according to claim 1.

49. A method of delivering a stent to a site comprising the steps of:

providing a stent delivery system, the stent delivery system comprising;

a stent delivery catheter, and

a stent according to claim 1,

advancing the stent delivery system to a vessels site; and

deploying the stent at the vessel site.

21. A stent having a proximal end, a distal end, a longitudinal axis extending through the proximal and distal ends, an as-cut state, a crimped state and an expanded state, wherein the stent is contractable from the as-cut state to the crimped state and expandable from the crimped state to the expanded state, the stent further comprising:

a plurality of axially spaced serpentine bands, each serpentine band comprising a plurality of struts, wherein adjacent struts are connected to each other forming a plurality of peaks and valleys, wherein the plurality of struts comprise a plurality of adjacent pairs of struts, each adjacent pair of struts comprising a first strut and a second strut, wherein the first and second struts have a first end, a second end and a length, each serpentine band further comprising strut pair opening angles formed by the first and second struts of the adjacent pairs of struts, the plurality of strut pair opening angles comprising a plurality of first opening angles and a plurality of second opening angles, wherein the first and second opening angles all face the same direction relative to the longitudinal axis of the stent and wherein, when the stent is in its as-cut state, the first opening angles are larger than the second opening angles and, when the stent is in its expanded state, the first opening angles are substantially similar to the second opening angles.

22. The stent of claim 21, wherein, when the stent is in its as-cut state, the first opening angles are at least twice as large as the second opening angles.

23. The stent of claim 21, wherein a plurality of the first opening angles are formed by a strut that is associated with a valley connector node and a strut that is not associated with a valley connector node.

24. The stent of claim 21, wherein all of the first opening angles are formed by strut pairs that have one strut associated with a valley connector node.

25. The stent of claim 21, wherein a plurality of the interconnecting struts that are associated with a valley connector node are connected to a peak of an adjacent serpentine band.

26. The stent of claim 21, the stent further comprising a plurality of node approach opening angles, each being formed by a strut and an interconnecting strut that are both associated with the same valley connector node, wherein, when the stent is in its as-cut state, the node approach opening angles are larger than the second opening angles.

27. The stent of claim 21, wherein, when the stent is in its expanded state, the first opening angles are substantially similar to the second opening angles.

28. The stent of claim 26, wherein, when the stent is in its crimped state, the first opening angles are substantially similar to the second opening angles and substantially similar to the node approach opening angles.