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EP-4093327-B1 - ENDOPROSTHESES WITH INTERLOCKING STENTS HAVING VARYING STIFFNESS

EP4093327B1EP 4093327 B1EP4093327 B1EP 4093327B1EP-4093327-B1

Inventors

  • SILVERMAN, JAMES D.
  • SKELTON, Tyson J.

Dates

Publication Date
20260506
Application Date
20210120

Claims (14)

  1. An endoprosthesis (100) having a length (106), a first end (102), a second end (104), and a longitudinal axis (107), the endoprosthesis being expandable from a compact, delivery configuration to an enlarged, deployed configuration, wherein the endoprosthesis (100) comprises: a plurality of rows of stent elements (108) along the length (106) of the endoprosthesis (100), the plurality of rows (108) including a first row (108A) and a second row (108B) located adjacent to the first row, the first row (108A) of stent elements having a first plurality of alternating apices (200A, 200B) and the second row (108B) of stent elements having a second plurality of alternating apices (200A, 200B), the first and second pluralities of alternating apices (200A, 200B) defining a spaced apart, interlocking arrangement, wherein the spaced apart, interlocking arrangement is defined by a portion of each of the first row and second row crossing over a center line located midway between the first and second rows and extending perpendicularly to the longitudinal axis, when the endoprosthesis is in the enlarged, deployed configuration; and a discontinuous web (110) of material comprising a plurality of web elements (118A) spaced from one another and interconnecting the first and second pluralities of alternating apices (200A, 200B), the plurality of web elements (118A) being arranged along a first, common circumference such that the plurality of web elements (118A) restrict torsion and axial compression of the endoprosthesis (100) between the first and second rows of stent elements (108A, 108B) when the endoprosthesis (100) is in the enlarged, deployed configuration; and wherein the plurality of web elements each extend at an acute angular offset relative to the circumference of the endoprosthesis (100) when the endoprosthesis (100) is in the enlarged, deployed configuration; or wherein the plurality of web elements (118A) each extend at an obtuse angle relative to the longitudinal axis (107) of the endoprosthesis (100) when the endoprosthesis (100) is in the enlarged, deployed configuration.
  2. The endoprosthesis of claim 1, wherein the discontinuous web (110) of material further comprises a second plurality of web elements (118B) spaced from one another and interconnecting the first and second pluralities of alternating apices (200A, 200B), the second plurality of web elements (118B) being arranged along a second, common circumference longitudinally spaced from the first, common circumference such that the second plurality of web elements (118B) restrict torsion and elongation of the endoprosthesis (100) between the first and second rows of stent elements (108A, 108B) when the endoprosthesis (100) is in the enlarged, deployed configuration.
  3. The endoprosthesis of claims 1 or 2, wherein the discontinuous web (110) of material is a polymeric film defining a plurality of apertures (116) between the first and second rows of stent elements (108A, 108B)
  4. The endoprosthesis of any one of claims 2 to 3, wherein the second plurality of web elements (118B) each extend at an angular offset relative to the circumference of the endoprosthesis (100).
  5. The endoprosthesis of any one of claims 1 to 4, wherein circumferentially-adjacent ones of the plurality of web elements (118A, 118B) extend at alternating, opposite angles relative to one another.
  6. The endoprosthesis of any one of claims 2 to 5, wherein the second plurality of web elements (118B), each extend at an acute angular offset relative to the circumference of the endoprosthesis (100) when the endoprosthesis (100) is in the enlarged, deployed configuration.
  7. The endoprosthesis of any one of claims 2 to 3, wherein the second plurality of web elements (118B), each extend along a circumference of the endoprosthesis (100).
  8. The endoprosthesis of any one of claims 1 to 6, wherein the first and second rows of stent elements (108A, 108B) and the plurality of web elements (118A, 118B) interconnecting the first and second pluralities of alternating apices (200A, 200B) of the first and second rows of stent elements are located within a first section (112) along the length (106) of the endoprosthesis (100), and further wherein a second section (113) of the endoprosthesis (100) along the length (106) of the endoprosthesis (100) includes a third row of stent elements (108C) having alternating apices (200A, 200B) and a fourth row of stent elements (108D) having alternating apices (200A, 200B), the third and fourth rows (108C, 108D) defining a spaced apart arrangement when the endoprosthesis (100) is in the enlarged, deployed configuration, the endoprosthesis (100) including a second discontinuous web (110) of material interconnecting the third and fourth row of stent elements (108C, 108D) such that the endoprosthesis (100) is axially compressible between the third and fourth rows of stent elements (108C, 108D) when the endoprosthesis (100) is in the enlarged, deployed configuration, optionally wherein the second discontinuous web of material (110) includes a plurality of web elements (118A) each extending at an acute angle with respect to the longitudinal axis (107) of the endoprosthesis (100).
  9. The endoprosthesis of claim 8, wherein one of: the first section (112) is adjacent the first end (102) of the endoprosthesis (100) and the second section (113) is located closer to a mid-point between the first (102) and second (104) ends of the endoprosthesis (100) than the first section; or wherein the endoprosthesis (100) is more axially rigid at the first section (112) than at the second section (113) when the endoprosthesis (100) is in the enlarged, deployed configuration; or the first section (112) is adjacent the first end (102) of the endoprosthesis (100) and the second section (113) is located closer to a mid-point between the first (102) and second (104) ends of the endoprosthesis (100) than the first section (112) and wherein the endoprosthesis (100) is more axially rigid at the first section (112) than at the second section (113) when the endoprosthesis (100) is in the enlarged, deployed configuration.
  10. The endoprosthesis of any one of claims 8 or 9, further comprising a third section (115) toward the second end (104) of the endoprosthesis (100) that is as axially rigid as the first section (112).
  11. The endoprosthesis of any one of claims 8 to 10, wherein the third and fourth rows (108C, 108D) define a spaced apart, interlocking arrangement when the endoprosthesis (100) is in the enlarged, deployed configuration; or wherein the third and fourth rows (108C, 108D) define a spaced apart, non-interlocking arrangement when the endoprosthesis (100) is in the enlarged, deployed configuration.
  12. The endoprosthesis of any one of claims 1 to 11, wherein the plurality of rows (108) of stent elements are formed of an elastically deformable material, optionally, a nickel-titanium alloy; or wherein the plurality of rows (108) of stent elements are formed of a plastically deformable material, optionally, a stainless steel alloy.
  13. The endoprosthesis of any one of claims 1 to 12, wherein the discontinuous web (110) of material comprises a thin film, optionally wherein the discontinuous web (110) of material comprises an ePTFE membrane.
  14. The endoprosthesis of any one of claims 1 to 13, wherein the first plurality of alternating apices (200A, 200B) are axially aligned with the second plurality of alternating apices (200A, 200B) to define a plurality of interlocked peaks and a plurality of interlocked valleys.

Description

This application claims the benefit of Provisional Application No. 62/963,917, filed January 21, 2020. FIELD The present disclosure generally relates to implantable medical devices, and more particularly, to implantable stents having flexibly connected adjacent stent elements. BACKGROUND Implantable stents are typically required to have a small, compact diameter for insertion into an intended body conduit, typically via a catheter, to a desired site for deployment, at which site they are expanded to a larger diameter. Balloon expandable stents are expanded with an inflatable balloon. Self-expanding stents are restrained at a compact diameter by a constraining sleeve or other means and spring open upon release. Self-expanding stents are generally formed of shape memory, or super-elastic materials that are biocompatible. Nitinol stents are one common material employed for self-expanding stents. The evolution of implantable stents has included the use of a tubular covering fitted to the stent. Covered stents have generally come to be referred to as stent-grafts. As an alternative to a continuous, or substantially continuous covering (e.g., substantially fluid impermeable covering), flexible elements (e.g., film or membrane material) may be employed to interconnect stent elements while leaving openings between the flexible elements. U.S. Patent 8,926,688 to Burkart et al., entitled "Stent Having Adjacent Elements Connected by Flexible Webs," describes such alternatives to covered stents. Burkart et al. describes stents incorporating flexible, preferably polymeric, connecting elements wherein these elements connect adjacent, spaced-apart stent elements. Generally, a fully covered stent-graft can be considered to have a surface area (hereinafter Amax) equal to the outer circumference of the expanded stent multiplied by the length of the stent. For a conventional, open frame stent (as opposed to a stent-graft), the surface area represented by all of the stent elements is only a small portion of the maximum surface area Amax. The actual surface area covered by the stent, meaning the area covered by all components of the stent (including connecting elements) in their deployed state, is Astent. The porosity index, or P.I., describes the open area (the portion of the maximum surface area not covered by all components of the stent assembly) as a percentage of maximum surface area, wherein: P.I. = (1 - (Astent / Amax)) × 100%. Some methods of measuring the actual surface area covered by the stent (Astent), involves the use of a machine provided Visicon Inspection Technologies, LLC (Napa, Calif.). The Visicon Finescan™ Stent Inspection System (Visicon Finescan machine model 85) uses a 6000 pixel line scan camera to generate a flat, unrolled view of a stent. In operation, the stent is mounted on a sapphire mandrel with a fine diffuse surface. This mandrel is held under the linear array camera and rotated by the system electronics and is used to trigger the linear array camera to collect a line of image data in a precise line-by-line manner. After a complete revolution an entire image of the stent is acquired. When the entire stent has been imaged, the software differentiates between the stent with cover and the background. The total number of picture elements (pixels) is compared to the total number of pixels associated with the stent and cover to determine Astent. Basic settings on the machine used for this type of determination are (for example): light, 100%; exposure, 0.3 ms/line; gain, 5; threshold, 50; noise filter, 20; smoothing, 4. The open area may be a continuous single space, such as the space between windings of a single helically wound stent element. Likewise the open area may be represented by the space between multiple individual annular or ring-shaped stent elements. The open area may also be represented by the total area of multiple apertures provided by either a single stent element (e.g., as shown by FIGS. 1B and 2B of U.S. Pat. No. 4,776,337 to Palmaz) or by multiple stent elements providing multiple apertures. If multiple apertures are provided, they may be of equal or unequal sizes. The use of a perforated graft covering or of polymeric elements in addition to metallic stent elements may also reduce the open area. Stents having a porosity index of greater than 50% are considered to be substantially open stents. In addition to the porosity index, the size of any aperture providing the open area must be considered if it is intended to cover only a portion of a stent area for a specific stent application. For multiple apertures, often the consideration must be for the largest size of any individual aperture, particularly if the apertures are to provide for a "filtering" effect whereby they control or limit the passage of biologic materials from the luminal wall into the flow space of the body conduit. Various stent devices combining metallic stent elements with polymeric connecting elements are known; se