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

• US 9,782,280 B2
• Filed: 01/11/2016
• Issued: 10/10/2017
• 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:
  US14/992,199
• Publication Number:
  US 20160120669A1
• Time in Patent Office: 638 Days
• 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 comprising cylindrical rings connected by links;

the struts having a transverse cross-section that is a four sided polygon, a first side and a second side are opposite each other and spaced apart by a distance h;

a third side and a fourth side are opposite each;

the first side and second side are parallel to each other and the third side and the fourth side are non-parallel to each other; and

the lengths of the first side, second side, third side and fourth side are selected so that a ratio of twisting resistance (J) to bending resistance (I_yc) in the struts is in the range from 1.508458 to 1.538975.

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

3. The stent of claim 2, wherein the second side forms an outer surface of the elongated tubular member.

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

5. The stent of claim 1, wherein the length of the first side is in the range from 0.0054 inch to 0.0052 inch and the second side is 0.0032 inch.

6. The stent of claim 5, wherein an aspect ratio of 1.34375 results from the first side length being 0.0054 inch, the second side length being 0.0032 inch, and the distance h being 0.0032 inch.

7. The stent of claim 5, wherein an aspect ratio 1.3125 results from the first side length being 0.0052 inch and the second side length being 0.0032 inch, and the distance h being 0.0032 inch.