Optimal ratio of polar and bending moment of inertia for stent strut design

• US 8,328,863 B2
• Filed: 04/22/2010
• Issued: 12/11/2012
• Est. Priority Date: 04/22/2010
• Status: Expired due to Fees

• Current Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories)
• Original Assignee: Abbott Cardiovascular Systems Incorporated (Abbott Laboratories)
• Inventors: Abunassar, Chad
• Primary Examiner(s): Sweet, Thomas J
• Assistant Examiner(s): PRESTON, REBECCA STRASZHEIM
• Application Number:
  US12/765,080
• Publication Number:
  US 20110264193A1
• Time in Patent Office: 964 Days
• Field of Search: None
• US Class Current: 623/1.15
• CPC Class Codes: A61F 2/82 Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95; for closing wounds, or holding wounds closed A61B17/04 - A61B17/115; dilators A61M29/00
• CPC Class Codes: A61F 2/848 having means for fixation to the vessel wall, e.g. barbs
• CPC Class Codes: A61F 2/89 the wire-like elements comprising two or more adjacent rings flexibly connected by separate members
• CPC Class Codes: A61F 2/915 with bands having a meander structure, adjacent bands being connected to each other
• CPC Class Codes: A61F 2/958 Inflatable balloons for placing stents or stent-grafts
• CPC Class Codes: A61F 2002/825 having longitudinal struts
• CPC Class Codes: A61F 2002/91558 connected peak to peak
• CPC Class Codes: A61F 2002/91566 connected trough to trough
• CPC Class Codes: A61F 2230/0013 Horseshoe-shaped, e.g. crescent-shaped, C-shaped, U-shaped
• CPC Class Codes: A61F 2230/0026 trapezoidal
• CPC Class Codes: A61F 2250/0036 differing in thickness
• CPC Class Codes: A61F 2250/0039 differing in diameter

Abstract

An intravascular stent is provided to be implanted in coronary arteries and other body lumens. The transverse cross-section of at least some of the stent struts have a ratio of polar and bending moments of inertia, which results in optimal resistance to stent twisting. This resistance to twisting ratio for the stent struts minimizes out of plane twisting of the struts or projecting edges of the struts when the stent is expanded from a compressed diameter to an expanded diameter in a coronary artery.

Claims

1. A stent, comprising:

an elongated tubular member having struts forming a stent pattern;

at least some of the struts each having a transverse cross-section that is a four sided polygon, a first side and a second side are opposite each other and have substantially the same height;

a third side and a fourth side are opposite each other, the third side being shorter than the fourth side; and

the lengths of the first side, second side, third side and fourth side are selected so that a ratio of twisting resistance to bending resistance in the at least some of the struts is 1.51.

2. The stent of claim 1, wherein the third side forms an inner surface of the elongated tubular member.

3. The stent of claim 1, wherein the fourth side forms an outer surface of the elongated tubular member.

4. The stent of claim 1, wherein the fourth side is longer than the first side and the second side.

5. The stent of claim 1, wherein at least some of the struts are linear and some of the struts are curved.

6. The stent of claim 1, wherein the third side and the fourth side are non-linear.

7. The stent of claim 6, wherein the third side and the fourth side are arcuate.

8. The stent of claim 1, wherein the third side forms an inner surface of the elongated tubular member and the fourth side forms an outer surface of the elongated tubular member.

9. A stent, comprising:

an elongated tubular member having struts forming a stent pattern;

at least some of the struts each having a transverse cross-section that is a trapezoidal-shaped polygon, a first side and a second side are opposite each other and have the same length;

a third side and a fourth side are opposite each other, the third side being shorter than the fourth side;

the length of the third side plus the length of the fourth side, divided by two, is longer than the length of the first side or the second side; and

the lengths of the first side, the second side, the third side and the fourth side are selected to provide a ratio of twisting resistance to bending resistance of the at least some of the struts of 1.51.