STENT WITH VARIABLE FEATURES TO OPTIMIZE SUPPORT AND METHOD OF MAKING SUCH STENT

• US 20100280593A1
• Filed: 05/10/2010
• Published: 11/04/2010
• Est. Priority Date: 09/19/1996
• Status: Active Grant

• Current Assignee: Medinol Limited (Medinol USA Incorporated)
• Original Assignee: Medinol Limited (Medinol USA Incorporated)
• Inventors: RICHTER, Jacob
• Granted Patent: US 7,998,193 B2
• Time in Patent Office: Days
• US Class Current: 623/1.16
• 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 2230/0054 V-shaped
• CPC Class Codes: A61F 2250/0018 differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2250/0042 differing in shape-memory transition temperatures, e.g. in martensitic transition temperature, in austenitic transition temperature
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

An intravascular stent especially suited for implanting in curved arterial portions or ostial regions. The stent can include an end region which is fabricated to have a greater radial strength than the remaining axial length of the stent. Such a stent is particularly suited for use in ostial regions, which require greater support near the end of the stent. The stent alternatively can include sections adjacent the end of the stent with greater bending flexibility than the remaining axial length of the stent. Such a stent is particularly suited for use in curved arteries. The stent can also be constructed with an end that has greater radial strength and sections adjacent the end with greater bending flexibility. Such a stent prevents flaring of the stent end during insertion.

Claims

1. An expandable stent, comprising:

a) a plurality of interconnected flexible cells defining a stent having a proximal end and a distal end and a longitudinal axis, the cells arranged in a plurality of interconnected flexible rows disposed along the longitudinal axis of the stent with a distal row disposed at the distal end of the stent and a proximal row disposed at the proximal end of the stent, each of the flexible cells comprising a first member, a second member, a third member and, a fourth member;

b) a first C-shaped loop disposed between the first member and the third member;

c) a second C-shaped loop disposed between the second member and the fourth member;

d) a first flexible connector disposed between the first member and the second member; and

e) a second flexible connector disposed between the third member and the fourth member, wherein the cells of the distal row have first and third members that are shorter than the second and fourth members.

2. The stent of claim 1, wherein the first and the third members in the cells of the distal row are about 15% shorter than the second and the fourth members.

3. An expandable stent, comprising:

a) a plurality of interconnected flexible cells defining a stent having a proximal end and a distal end and a longitudinal axis, the cells arranged in a plurality of interconnected flexible rows disposed along the longitudinal axis of the stent with a distal row disposed at the distal end of the stent and a proximal row disposed at the proximal end of the stent, each of the flexible cells comprising a first member, a second member, a third member and, a fourth member;

b) a first C-shaped loop disposed between the first member and the third member;

c) a second C-shaped loop disposed between the second member and the fourth member;

d) a first flexible connector disposed between the first member and the second member; and

e) a second flexible connector disposed between the third member and the fourth member, wherein the cells of the proximal row have second and fourth members that are shorter than the first and third members.

4. The stent of claim 3, wherein the second and the fourth members in the cells of the proximal row are about 15% shorter than the first and the third members.

5. An expandable stent comprising:

a) a plurality of flexible cells defining a stent having a proximal end and a distal end and a longitudinal axis, the cells arranged in a plurality of flexible rows along the longitudinal axis with a distal row of cells disposed at the distal end of the stent and a proximal row of cells disposed at the proximal end of the stent, each of the flexible cells comprising a first member, a second member, a third member, and a fourth member;

b) a first C-shaped loop disposed between the first member and the third member;

c) a second C-shaped loop disposed between the second member and the fourth member;

d) a first flexible connector disposed between the first member and the second member; and

e) a second flexible connector disposed between the third member and the fourth member, wherein the cells of the distal row have first and third members that are shorter than the second and fourth members, and wherein the cells of the proximal row have second and fourth members that are shorter than the first and third members.

9. An expandable stent having a proximal end, a distal end and a longitudinal axis, comprising:

a) a plurality of first circumferential bands arranged along the longitudinal axis of the stent, each first circumferential band defining a generally serpentine pattern comprising a plurality of strut members and a plurality of loops;

b) a second circumferential band disposed at least at one end of the stent, each second circumferential band defining a generally serpentine pattern comprising a plurality of strut members and a plurality of loops, wherein the strut members of each second circumferential band are shorter in length than the strut members of each first circumferential band; and

c) a plurality of flexible connectors coupling adjacent circumferential bands.

10. The stent of claim 9 where the strut members of each second circumferential band have a length in the longitudinal direction of the stent that is less than the length in the longitudinal direction of the strut members of each first circumferential band.

11. The stent of claim 9, wherein a second circumferential band is disposed at the distal end of the stent.

12. The stent of claim 9, wherein a second circumferential band is disposed at the proximal end of the stent.

13. The stent of claim 9, wherein a second circumferential band is disposed at the distal end of the stent and a second circumferential band is disposed at the proximal end of the stent.

14-67. -67. (canceled)

68. An expandable stent, comprising a plurality of interconnected flexible cells defining a stent having a proximal end and a distal end and a longitudinal axis and which when expanded in a lumen exerts radial force along its length against the lumen wall, the cells arranged in a plurality of interconnected flexible rows disposed along the longitudinal axis of the stent with a distal row disposed at the distal end of the stent and a proximal row disposed at the proximal end of the stent, wherein a row of cells at an end of the stent exerts greater radial force than each row of cells disposed between the distal row and the proximal row of the stent.

6. The stent according to claim 68, wherein said end row of cells comprises the distal row of cells.

7. The stent according to claim 68, wherein said end row of cells comprises the proximal row of cells.

8. The stent according to claim 68, wherein said end row of cells comprises each of the distal row cells and the proximal row of cells.

69. A method of making an expandable stent having increased radial strength at an end, comprising:

etching a stent pattern, said stent pattern comprising a longitudinal axis having a first end and a second end, a plurality of bands arranged along said longitudinal axis of said stent pattern, and a plurality of flexible connectors disposed between adjacent bands, wherein each of said bands defines a generally serpentine pattern comprising strut members alternating with C-shaped members, and wherein at least one of said serpentine bands at an end of said stent pattern imparts greater radial force than serpentine bands between said first and second ends.

70. The method of claim 69, wherein said strut members of said end serpentine band configured to impart greater radial force are shorter than said strut members in serpentine bands between said first and second ends.

71. The stent according to claim 69 or 70, wherein said etching step includes etching said stent pattern into a flat sheet, said stent pattern further comprising a first longitudinal side, a second longitudinal side;

said method further comprising;

forming said stent pattern into a tubular shape so that said first and second longitudinal sides meet, and so that said plurality of serpentine bands become a plurality of circumferential serpentine bands.

72. A method of making an expandable stent having increased radial strength at an end, comprising:

etching a stent pattern, said stent pattern comprising a longitudinal axis having a first end and a second end, and a plurality of flexible cells arranged in a plurality of flexible rows, said flexible rows of cells arranged along said longitudinal axis, wherein each of said flexible cells comprises a first member, a second member, a third member, and a fourth member, a first C-shaped loop disposed between the first member and the third member, a second C-shaped loop disposed between the second member and the fourth member, a first flexible connector disposed between the first member and the second member, and a second flexible connector is disposed between the third member and the fourth member, wherein cells of an end row at an end of said stent pattern are configured to impart greater radial force than cells in rows between said first and second ends of said stent pattern.

73. The stent according to claim 72, wherein said end having end row cells configured to impart greater radial force is said first end, and said end row of cells of said first end have first and third members that are shorter than said second and fourth members.

74. The stent according to claim 72, wherein said end configured to impart greater radial force is said second end, and said end row of cells of said second end have second and fourth members that are shorter than said first and third members.

75. The stent according to claim 72, wherein said end configured to impart greater radial force includes said first end and said second end, and said end row of cells of said first end have first and third members that are shorter than said second and fourth members, and said end row of cells of said second end have second and fourth members that are shorter than said first and third members.

76. The stent according to any one of claims 72-75, wherein said etching step includes etching said stent pattern into a flat sheet, said stent pattern further comprising a first longitudinal side, a second longitudinal side;

said method further comprising;

forming said stent pattern into a tubular shape so that said first and second longitudinal sides meet.

77. A method of making an expandable stent having increased radial strength at an end, comprising:

twisting a wire into a stent pattern, said stent pattern comprising a longitudinal axis having a first end and a second end, a plurality of bands arranged along said longitudinal axis of said stent pattern, and a plurality of flexible connectors disposed between adjacent bands, wherein each of said bands defines a generally serpentine pattern comprising strut members alternating with C-shaped members, and wherein at least one of said serpentine bands at an end of said stent pattern is configured to impart greater radial force than serpentine bands between said first and second ends.

78. The method of claim 77, wherein said strut members of said at least one end serpentine band configured to impart greater radial strength are shorter than said strut members of said serpentine bands between said first and second ends.

79. The method of claim 77 or 78, further comprising:

welding a plurality of contact points of said twisted wire.