阅读说明：本技术 具有提高的柔韧性的支架移植物 (Stent graft with improved flexibility ) 是由 D·S·埃内斯 R·金 I·坦皮亚 C·斯托登梅耶 于 2016-05-11 设计创作，主要内容包括：一种柔性支架移植物具有聚合物非纺织物移植物层,其中支架设置在两个或更多个移植物层之间,同时允许支架在两个或更多个层之间移动。支架包括设置在移植物层之间的非固定移植物部分的袋内的波状丝支架。支架可以是具有移植物层的一个或多个带的带状支架。(A flexible stent graft has polymer non-woven graft layers, where the stent is disposed between two or more graft layers while allowing the stent to move between the two or more layers. The stent comprises a wavy wire stent disposed within a pocket of the non-fixed graft portion between layers of the graft. The stent may be a ribbon stent having one or more ribbons of a graft layer.)

1. An endovascular stent-graft comprising a ribbon stent-graft, the ribbon stent-graft comprising:

a tubular stent wall having opposed first and second ends;

a wavy wire having a thickness and having opposed first and second wire ends and helically wound in a plurality of approximately circumferential turns to define the stent wall;

said undulating wire having a plurality of undulations defined by peaks and valleys and intermediate wire portions coextensive with said peaks and said valleys, wherein said peaks of adjacent approximately circumferential windings are spaced a distance apart;

the first wire end is secured to a first wave at the first end;

the second wire end is secured to a second wave at the second end;

an elongate planar tape liner having opposite first and second end portions and an intermediate portion therebetween, said planar tape liner comprising a layer of a non-woven polymeric graft material; and

an elongate planar tape cover having opposite first and second end portions and an intermediate portion therebetween, said planar tape liner comprising a layer of a non-woven polymeric graft material;

wherein the elongate ribbon cover is disposed over the mid-wire portion;

wherein the elongate tape liner is disposed below the intermediate wire portion; and is

Wherein the elongate tape covering and the elongate tape liner are securely disposed to each other and the intermediate wire portion.

2. The endovascular stent-graft as defined in claim 1, a width of the elongate ribbon cover and a width of the elongate ribbon liner do not extend to the peaks and valleys of the undulating wire.

3. The endovascular stent-graft of claim 1, further comprising:

a tubular graft liner having opposed first and second end portions and an intermediate portion between the first and second end portions, the graft liner comprising a layer of a non-woven polymeric graft material; and

a tubular graft covering having opposing first and second end portions and an intermediate portion between the first and second end portions, the graft covering comprising a layer of a non-woven polymeric graft material;

wherein the first end portion of the tubular graft liner and the first end portion of the tubular graft covering are secured to one another to define a fused first end;

wherein the second end portion of the tubular graft liner and the second end portion of the tubular graft covering are secured to one another to define a fused second end;

wherein at least a portion of the intermediate portion of the tubular graft cover and tubular graft liner are not secured to one another, defining a non-secured tubular graft portion at the at least a portion, the non-secured tubular graft portion defining a graft lumen between the tubular graft liner and tubular graft cover; and is

Wherein the ribbon stent graft is disposed within the graft lumen.

4. The endovascular stent-graft of claim 3, further comprising a plurality of non-stationary tubular graft portions.

5. The endovascular stent-graft of claim 3, wherein the non-stationary tubular graft portion extends substantially along the graft covering and the intermediate portion of the graft liner.

6. The endovascular stent-graft of claim 3, wherein the tubular graft covering between the first and second ends is configured to form a pleated portion upon longitudinal compression or axial bending of the endovascular stent-graft.

7. The endovascular stent-graft of claim 3, wherein the tubular graft covering between the first and second ends is configured to form a crimped portion upon longitudinal compression or axial bending of the endovascular stent-graft.

8. The endovascular stent-graft of claim 2, wherein adjacent proximal circumferential windings are free of interconnected struts and welds, except for the first and second wire end portions secured to the first and second undulations, respectively.

9. The endovascular stent-graft of claim 2, wherein the layer of non-woven polymeric graft material for the elongate tape-like covering comprises polytetrafluoroethylene selected from the group consisting of: porous polytetrafluoroethylene free of distinguishable node and fibril microstructure; expanded polytetrafluoroethylene having a node and fibril microstructure; polytetrafluoroethylene having low or substantially no fluid permeability, comprising a closed-cell microstructure having a high density region with grain boundaries directly interconnected with grain boundaries of an adjacent high density region, and substantially free of node and fibril microstructure; porous polytetrafluoroethylene that is not or substantially not fluid permeable; semi-permeable polytetrafluoroethylene; permeable polytetrafluoroethylene; and combinations thereof.

10. The endovascular stent-graft of claim 2, wherein the layer of non-woven polymeric graft material for the elongate tape-like liner comprises polytetrafluoroethylene selected from the group consisting of: porous polytetrafluoroethylene free of distinguishable node and fibril microstructure; expanded polytetrafluoroethylene having a node and fibril microstructure; polytetrafluoroethylene having low or substantially no fluid permeability, comprising a closed-cell microstructure having a high density region with grain boundaries directly interconnected with grain boundaries of an adjacent high density region, and substantially free of node and fibril microstructure; porous polytetrafluoroethylene that is not or substantially not fluid permeable; semi-permeable polytetrafluoroethylene; permeable polytetrafluoroethylene; and combinations thereof.

11. The endovascular stent-graft of claim 3, wherein the layer of non-woven polymeric graft material for the tubular graft covering comprises polytetrafluoroethylene selected from the group consisting of: porous polytetrafluoroethylene free of distinguishable node and fibril microstructure; expanded polytetrafluoroethylene having a node and fibril microstructure; polytetrafluoroethylene having low or substantially no fluid permeability, comprising a closed-cell microstructure having a high density region with grain boundaries directly interconnected with grain boundaries of an adjacent high density region, and substantially free of node and fibril microstructure; porous polytetrafluoroethylene that is not or substantially not fluid permeable; semi-permeable polytetrafluoroethylene; permeable polytetrafluoroethylene; and combinations thereof.

12. The endovascular stent-graft of claim 3, wherein the layer of non-woven polymeric graft material for the tubular graft liner comprises polytetrafluoroethylene selected from the group consisting of: porous polytetrafluoroethylene free of distinguishable node and fibril microstructure; expanded polytetrafluoroethylene having a node and fibril microstructure; polytetrafluoroethylene having low or substantially no fluid permeability, comprising a closed-cell microstructure having a high density region with grain boundaries directly interconnected with grain boundaries of an adjacent high density region, and substantially free of node and fibril microstructure; porous polytetrafluoroethylene that is not or substantially not fluid permeable; semi-permeable polytetrafluoroethylene; permeable polytetrafluoroethylene; and combinations thereof.

13. The endovascular stent-graft of claim 3, wherein the tubular graft liner and the tubular graft covering are laminated or adhesively bonded to each other at the fixation graft portion.

14. The endovascular stent-graft of claim 3, wherein the endovascular stent-graft is configured to bend about 180 ° with a gap of about 6mm or less between portions of the tubular graft covering proximal to the bend; and wherein the endovascular stent-graft is retained in a substantially tubular shape by the bend.

15. The endovascular stent-graft of claim 3, wherein the endovascular stent-graft is configured to bend about 180 ° or more without a substantial reduction in diameter of the endovascular stent-graft in a portion of the bend.

16. The endovascular stent-graft of claim 3, wherein the tubular graft liner and the fixed tubular graft portion of the tubular graft covering are free of sutures.

Technical Field

The present technology relates to stent grafts. In particular, the present technology relates to flexible stent grafts having polymeric nonwoven graft layers wherein the stent is disposed between two or more graft layers while allowing the stent to move between the two or more layers.

Background

The stent graft may comprise a stent associated with one or more layers of textile graft. As used herein, a textile graft layer refers to a layer formed by a typical textile process such as weaving, knitting, braiding, and the like. Sutures are commonly used to secure the stent to the graft layer. A disadvantage of such textile-containing stent grafts is the high profile, i.e. relatively thick, layer of textile fabric, especially in cases where the stent graft is to be fluid-tight, e.g. in order to restrict, prevent or otherwise control blood flow through some or all of the textile fabric walls of the graft layer or layers.

To reduce the profile of the stent graft, a layer of polymeric nonwoven may be used. As used herein, polymeric nonwoven layer refers to a sheet or cylinder of polymeric material, such as but not limited to extruded polymeric sheets and cylinders. Typically, such stent grafts may be fabricated on a cylindrical mandrel, with the graft laminated in a purely cylindrical form, which limits the motion of the stent graft when attempting to accommodate longitudinal compression. However, the ability of the stent graft to be longitudinally compressed is useful so that the stent graft can bend and more readily conform to particular anatomical structures, and facilitate introduction or delivery procedures. However, shear forces are often present in certain stent grafts, which limit the amount of flexibility when the stent graft is manufactured in a pure cylindrical form. This is particularly the case when the top or outer layer and the bottom or inner layer are fully fused together during the formation of the stent graft.

Accordingly, there is a need for a flexible stent graft having one or more polymer nonwoven graft layers, wherein the stent is disposed between two or more graft layers.

Disclosure of Invention

The present technology provides a low profile flexible stent graft having a polymer nonwoven graft layer, wherein the stent is disposed between two or more graft layers. One or more layers of nonwoven graft may be fabricated to have increased flexibility between the zig-zag or open lattice of the stent. In addition, the stent grafts of the present technology may contain areas where the inner and outer graft layers are not laminated to one another, thereby allowing the stent portion to move or float between such open pockets of graft material. In some embodiments, a substantial portion of the scaffold may be free floating between the graft layers. Other methods and embodiments are described for removing or reducing the constraint, thereby allowing the stent to float freely within the graft material to varying degrees, e.g., fully, substantially, significantly, or partially.

In one embodiment, an intravascular stent graft includes: a tubular stent wall having opposed first and second ends; a wavy wire having a thickness and having opposite first and second ends and helically wound into a plurality of approximately circumferential turns to define a stent wall; the undulating wire has a plurality of undulations defined by peaks and valleys, the peaks of adjacent approximately circumferential windings being spaced apart by a distance; a first wire end secured to the first wave at a first end; a second wire end is secured to the second wave at a second end; an implant liner comprising a layer of a non-woven polymeric implant material; and a graft covering comprising a layer of non-woven polymeric graft material. The graft liner and the graft cover can be selectively secured to one another, defining a fixed graft portion at the graft liner and the graft cover, and defining a non-fixed graft portion between the graft liner and the graft cover, the non-fixed graft portion defining a graft lumen between the graft liner and the graft cover. A tubular stent wall is disposed within the graft lumen. The graft cavity may have a longitudinal extent greater than the thickness of the undulating wire.

In another embodiment, an intravascular stent graft includes: a tubular stent wall having opposed first and second ends; a wavy wire having a thickness and having opposite first and second ends and being helically wound into a plurality of approximately circumferential turns to define a stent wall; the undulating wire having a plurality of undulations defined by peaks and valleys, the peaks of adjacent approximately circumferential windings being spaced apart by a distance; a first wire end is secured to the first wave at a first end; a second wire end is secured to the second wave at a second end; a graft lining having opposed first and second end portions and an intermediate portion therebetween, the graft lining comprising a layer of a non-woven polymeric graft material; and a graft covering having opposed first and second end portions and an intermediate portion therebetween, the graft covering comprising a layer of a non-woven polymeric graft material; wherein the first end portion of the graft lining and the first end portion of the graft covering are secured to one another; wherein the second end portion of the graft lining and the second end portion of the graft covering are secured to one another; wherein at least one of the graft covering and the intermediate portion of the graft lining are secured to one another, defining a non-fixed graft portion at the at least one portion, the non-fixed graft portion defining a graft lumen between the graft lining and the graft covering; and wherein the tubular stent wall is disposed within the graft lumen.

In yet another embodiment, an intravascular stent graft includes a ribbon stent graft comprising: a tubular stent wall having opposed first and second ends; a wavy wire having a thickness and having opposite first and second ends and helically wound into a plurality of approximately circumferential turns to define a stent wall; the undulating wire having a plurality of undulations defined by peaks and valleys and intermediate wire portions coextensive with the peaks and valleys, wherein peaks of adjacent approximately circumferential windings are spaced a distance apart; a first wire end is secured to the first wave at a first end; a second wire end is secured to the second wave at a second end; an elongate planar tape liner having opposed first and second end portions and an intermediate portion therebetween, the planar tape liner comprising a layer of a non-woven polymeric graft material; and an elongate planar tape covering having opposite first and second end portions and a middle portion therebetween, the planar tape liner comprising a layer of non-woven polymeric graft material; wherein the elongate ribbon shroud is disposed over the mid-wire portion; wherein the elongate tape liner is disposed below the intermediate wire portion; wherein the elongate tape covering and the elongate tape lining are securely arranged to each other and to the intermediate wire portion. The endovascular stent-graft can also include: a tubular graft liner having opposed first and second end portions and an intermediate portion therebetween, the graft liner comprising a layer of a non-woven polymeric graft material; and a tubular graft covering having opposed first and second end portions and an intermediate portion therebetween, the graft lining comprising a layer of non-woven polymeric graft material; wherein the first end portion of the tubular graft liner and the first end portion of the tubular graft covering are secured to each other; the second end portion of the tubular graft liner and the second end portion of the tubular graft covering are secured to one another; wherein at least a portion of the intermediate portion of the tubular graft cover and tubular graft liner are not secured to one another, defining a non-secured tubular graft portion at the at least a portion, the non-secured tubular graft portion defining a tubular graft liner and a tubular graft cover; and wherein the ribbon stent graft is disposed within the graft lumen.

These features of the embodiments will become more apparent from the following detailed description in conjunction with the accompanying exemplary drawings. Corresponding element reference numerals or characters indicate corresponding parts throughout the several views of the drawings.

Drawings

Fig. 1 is a perspective and schematic view of a stent graft according to the present technique.

Fig. 2 is a side elevation view of the stent graft of fig. 1 taken along the 2-2 axis depicting a stent according to the techniques of the present invention.

Fig. 3 is a side elevational view of the stent graft of fig. 2 with graft material trimmed from the ends of the stent graft.

Fig. 4 is a cross-sectional view of the stent graft of fig. 2 taken along the 4-4 axis.

Fig. 5 is a partial side elevational view of a stent graft according to the present techniques, showing a portion of an undulating wire stent disposed within a graft lumen or a non-fixed graft portion defined by a graft fixation portion.

Fig. 6 is a partial cross-sectional view of the stent graft of fig. 5.

Fig. 7 depicts the stent graft of fig. 6 partially compressed.

Fig. 8-10 depict the stent graft of fig. 5 with various embodiments of graft securing portions.

Figure 11 is a partial view of a stent crown of a stent graft according to the present technique.

Fig. 12A-12D depict various embodiments of graft fixed and non-fixed portions forming pleats or pleats.

Fig. 13A depicts a stent graft disposed between a graft covering and a graft liner having graft ends secured to one another in accordance with the techniques of the present invention.

Fig. 13B depicts another embodiment of the stent graft of fig. 13A.

Fig. 14 is a cross-sectional view of the stent graft of fig. 13A taken along the 14-14 axis.

Fig. 15 is a cross-sectional view of the stent graft of fig. 13A taken along the 15-15 axis.

Fig. 16 is a partial side elevational view of a stent graft according to the techniques of the present invention, showing the orientation of the stent filaments as the stent graft is bent.

Fig. 17 is a partial front view of a stent graft according to the techniques of the present invention showing the orientation of the stent filaments as the stent graft is longitudinally compressed.

Fig. 18A-18D depict graft pleats and graft pleats according to techniques of the present disclosure.

Fig. 19 depicts the formation of graft pleats upon longitudinal compression of a stent graft in accordance with the present techniques.

Fig. 20 depicts a bend of a stent graft according to the techniques of the present invention, where the stent wire element is movable near the bend and the graft portion forms a pleat near the bend.

Fig. 21 depicts the bending of a prior art stent graft.

Fig. 22 depicts increased bending of the stent graft of fig. 20.

Fig. 23 depicts the increased bending of the prior art stent graft of fig. 21.

FIG. 24 depicts the formation of a ribbon stent graft on a mandrel according to the techniques of the present invention.

Fig. 25 and 26 depict the ribbon stent graft of fig. 24.

Fig. 27 and 28 depict the bending of an endovascular stent-graft in accordance with the techniques of the present invention with the ribbon stent-graft of fig. 25 and 26.

Fig. 29 and 30 depict a ribbon-like stent graft with axial ribbons according to the present technique.

FIG. 31 depicts one embodiment of a stent structure useful in the present techniques.

Fig. 32A and 32B depict various embodiments of stent structures that may be used with the present techniques.

Fig. 33A-33E depict various arrangements of a helically wound stent of the present technology.

Fig. 34A and 34B depict stent-graft assemblies that can be used with the present techniques.

Detailed Description

For the graft, stent, or stent-graft embodiments and components thereof discussed herein, the term "proximal" refers to a location toward the patient's heart, while the term "distal" refers to a location away from the patient's heart. For the delivery system catheters and components thereof discussed herein, the term "distal" refers to a location disposed away from an operator using the catheter, while the term "proximal" refers to a location toward the operator.

FIG. 1 is a perspective and schematic view of a stent graft 10 in accordance with the present techniques, the stent graft 10 being a hollow tubular device having a tubular wall 12, a first open end 14, and an opposing second open end 16 to define an open lumen 18, the tubular wall 12 having a longitudinal length L or an axis L, although the stent graft 10 is depicted in FIG. 1 as being substantially tubular, the present techniques are not so limited, for example, portions of the stent graft wall 12 at either or both of the open ends 14,16 may be flared (inward or outward) or flanged (inward or outward), further, portions of the stent graft wall 12 between the open ends 14,16 may also have non-straight tubular portions, such as portions along the flared (inward or outward) portion of the stent graft wall 12 or having a curved bend.

Furthermore, the techniques of the present invention are not limited to a continuous tubular wall 12 as depicted in FIG. 1. For example, the stent graft 10 may have one or more fenestrations (not shown) in the tubular wall 12. Such fenestrations may be useful in a branch lumen where additional stent-grafts may be deployed and enter the fenestrations. In addition, the stent graft 10 may have one or more side branches (not shown) extending from a middle portion of the tubular wall 12 for deployment into or toward the branch lumens.

Fig. 2 is a side elevational view of the stent graft 10 of fig. 1 taken along the 2-2 axis. The stent graft 10 includes a stent 20 formed from undulating filaments 22. The wavy filaments 22 may be helically wound or otherwise formed into a stent 20 having a series of peaks 28 and valleys 30. Further details of the stent 20 are described below in connection with fig. 31, fig. 32A-32B, fig. 33A-33E, and fig. 34A-34B. The stent graft 10 includes a graft covering 24. A graft lining 26 (not shown) is disposed beneath the graft covering 24. Further details of the graft covering 24 and graft lining 26 and graft lining are described below in connection with fig. 34A and 34B. The graft covering 24 and graft lining 26 can be one or more layers of polymeric material.

The graft covering 24 (and graft lining 26-not shown) may extend to the first end 14 and the second end 16 of the stent graft 10. As depicted in fig. 2, the stent graft 10 may have a graft covering and graft lining material (not shown) extending beyond the end portions of the undulating wire at the first end 14 and the second end 16. Such a configuration may be useful, for example, where additional areas for fusing other graft components at first end 14 and second end 16 are desired. However, the technique of the present invention is not limited thereto. For example, as depicted in fig. 3, embodiments of the stent graft 10 may have the graft covering 24 (and graft lining 26-not shown) trimmed from the first end 14 and the second end 16, or be absent.

Fig. 4 is a cross-sectional view of the stent graft 10 of fig. 1 taken along the 4-4 axis. As depicted in fig. 2, the stent 20 is disposed between a graft covering 24 and a graft lining 24. Unlike typical prior art stent grafts, the stent 20 or portions of the stent 20 of the present technology are free to move or float between the graft covering 24 and the graft lining 26. This self-movement or floating imparts greater flexibility to the stent graft 10 of the present technology during assembly as well as during and after deployment than prior art stent grafts.

Fig. 5 is a partial side elevational view of the stent graft 10 of fig. 1 showing a portion of the undulating wire 22 disposed within the graft lumen 38 or the non-stationary graft portion 38. The undulating wire 22 is disposed between a graft covering 24 and a graft liner 26. The fixed graft portion 36 may be formed around both sides of the undulating wire 22. As depicted in fig. 5, the peaks 28, valleys 30, and intermediate portions 32 of the wavy filaments 22 may be disposed within a graft lumen 38 or a non-fixed graft portion 38. The terminal portions of the peaks 28 and/or valleys 30 may be referred to as crowns 34, which will be described in further detail below. Although fig. 5 depicts the entire portions of the peaks 28, valleys 30, crowns 34, and medial portion 32 of the undulating wire 22 as being disposed within the graft cavity 38 or the non-stationary graft portion 38, the present techniques are not so limited. By way of example only, only portions of the peaks 28, valleys 30, crowns 34, and/or medial portion 32 of the undulating wire 22 may be disposed within the graft cavity 38 or the non-fixed graft portion 38.

The fixation graft portion 36 may be formed by applying heat with or without pressure (e.g., lamination), by adhesive bonding, ultrasonic bonding, or any combination thereof. The fixed graft portion 36 may be laminated by selective application of heat, such as by use of a laser or heated probe. Additionally, a tool (not shown) may be provided below the portion 38 to assist in forming the fixation graft portion 36 when the stent graft 10 is positioned on a mandrel (not shown). In addition, an inflation tool (not shown) may be used to provide an inflation medium, such as, but not limited to, air or other suitable fluid, to inflate the area between the graft covering 24 and the graft lining 26 to form the cavity 38 after selectively securing a portion of the graft covering 26 and the graft lining 26 to one another. Further, the techniques of the present invention are not limited to forming graft lumens 38 having stents 20 or undulating filaments 22 disposed therein. If desired, the graft cavity 38 can be formed at a location within the graft covering 26 and graft lining 26 that does not have a portion of the stent 20. Between the wavy filament 22 and the fixed graft portion 36 is a non-fixed graft portion 38 or graft lumen portion 38. Such an unsecured graft portion or lumen 38 allows the undulating filaments 22 or stent 20 to move within the stent graft 10 as the stent graft moves (e.g., without limitation, bending of the stent graft 10, axial or longitudinal compression or expansion of the stent graft 10, radial compression or expansion of the stent graft 10). Such stent-graft movement is often encountered during deployment of the stent-graft 10 to a desired body location or lumen or even after deployment of the stent-graft 10 within the body.

In one embodiment of the present technique, a method may involve welding or bonding (by heat, ultrasound, adhesive, or other means) the pathways between stent members or zigzags to seal each zigzag pattern within its own pocket or area of non-laminated graft material layer. Sintering/lamination can be accomplished with minimal pressure, e.g., no compressive force during lamination, such as is typically used with shrink or compressible tubes, so that the graft layers are not typically fused together locally around the stent member or filament, thereby allowing free relative movement within the pocket of the non-laminated graft layer. Such selective welding may simply leave a weld line path between stent members or wires. Devices having a hot tip or ultrasonic horn may be suitable for forming such weld lines. The device may be operated manually or may be automated, i.e. robotic movement control.

Fig. 6 is a partial cross-sectional view of the stent graft 10 of fig. 1. The undulating wire 22 is movable within the graft cavity 38. For example, as depicted in fig. 7, when the stent graft 10 of fig. 6 is compressed, the wavy filaments are free to move within the lumen 38. Further, the graft covering 24 and/or graft lining 26 may also be free to move when compressed, as depicted in fig. 7 (both the graft covering 24 and graft lining may be free to move).

As depicted in fig. 6, the fixed graft portion 36 may have a short or small longitudinal extent 35, e.g., less than or substantially less than the diameter 37 of the wavy wire 22 or, e.g., about the diameter 37 of the wavy wire 22. The longitudinal extent 39 of the non-fixation portion or lumen 38 may be greater than the small longitudinal extent 35 and may be greater than the diameter 37 of the wavy filaments. However, the technique of the present invention is not limited thereto. A substantial portion or substantial portion of the graft covering 24 and graft lining 26 may be secured to one another, such as substantial or substantial covering 24 and lining 26 portions between adjacent undulating wire portions. Such substantial or basic cover and liner portions 24, 26 forming the fixed graft portion 36 may be about the size of the diameter of the wavy filaments 22 or significantly larger.

In general, as the volume or extent of the graft lumen 38 increases relative to the undulating filaments 22, the flexibility of the stent graft 10 may also increase. However, the techniques of the present invention are not limited to increasing the volume or extent of the graft lumen 38 to increase the flexibility of the stent graft 10, and other techniques such as crimping and/or pleating, as described below, may be suitably used.

Furthermore, the techniques of the present invention are not limited to a fixed graft portion 36 surrounding a wavy wire 22 as depicted in fig. 5. For example, as depicted in fig. 8, the fixed graft portion 36 may be formed at the intermediate portion 32 of the wavy filament 22 between the peaks 28 and valleys 30 of the wavy filament. An unsecured graft portion or lumen 38 is formed with the fixed graft portion 36. This configuration allows for an increased likelihood of free movement of the peaks 28 and valleys 30 as compared to stent grafts having peaks and valleys encapsulated between graft components, as these peaks 28 and valleys 30 move substantially unrestrained, e.g., longitudinally and/or non-longitudinally, such as curved.

Further, as depicted in fig. 9, the fixed graft portion 36 may be located at the peaks 28 or crowns 34 of the undulating wire 22. Although the fixed graft portion 36 in fig. 9 is depicted as being located on only one side of the peak 28, the techniques of the present invention are not so limited. For example, the fixation graft portion 36 may be disposed on both sides of the peak 28 (not shown). In addition, some of the fixation graft portions 36 may be disposed on one side of the peak 28 toward one end of the stent graft 10 (e.g., the second end 16 of the stent graft 10), while other fixation graft portions 36 may be disposed on the other side of the peak toward the other end of the stent graft 10 (e.g., the first end 14 of the stent graft 10).

Further, as depicted in fig. 10, the fixed graft portion 36 may be formed laterally across a portion of the undulating wire 22, such as the depicted intermediate portion 32 or peak portion 28 (not shown) or valley portion 30 (not shown). While the embodiment of fig. 10 may represent an easier manufacturing technique for forming the fixed graft portion 36, because the specific geometry of the undulating filaments 22 need not be precisely followed, increased stent graft flexibility is still achieved compared to prior art stent grafts that completely encapsulate the stent within the graft layer.

The various configurations of the graft securing portion 36 as depicted in and described in connection with fig. 5-10 may be used alone or in any combination.

Fig. 11 is a top view of the crown 34 of the wavy filament 22. Fig. 12A-12D depict different arrangements of the graft covering 24 and graft lining 26 around the crowns 34 of the stent graft 10 of the present technique.

As depicted in fig. 12A, the graft covering portion 42 of the graft covering 24 can be disposed about the silk portion of the crown 34. Graft covering portion 42 is disposed on at least one side of crown 34. In addition, graft covering portion 42 can also be disposed above the top of crown 34 and below at least a portion of the bottom of crown 34. The graft lining 26 can have a raised graft lining portion 40 located below a portion of the crown 34. Although the graft cover 24 and graft liner 26 are secured to one another at the graft securing portion 36, the graft cover 24 and graft liner 26 may not be fully or directly secured to the crown 34, allowing the crown 34 to move between and along the graft cover 24 and graft liner 26. For example, if desired, a portion of the graft covering 42 can be laminated to the crown 34, as shown in fig. 12A.

As also depicted in fig. 12A, the graft covering pleats or pleat portions 44 are formed by the elevation of the crown 34, graft covering 24, and graft lining 26 over the longitudinal wall 12 of the stent graft 10. During manufacture, a tool (not shown) may be used to raise the portions above a mandrel (not shown) for lamination thereto. The pleated or pleated portion 44 provides flexibility at the crown 34 of the stent graft 10 during bending and/or compression. As described below, such increased flexibility includes, but is not limited to, increased longitudinal flexibility during longitudinal compression and/or expansion and increased radial flexibility, as limited or small crown movement in the radial direction is permitted upon bending or even longitudinal compression.

As depicted in fig. 12B, the technique of the present invention does not necessarily have a raised liner portion 40. A pleat or pleat 44 can be disposed below a portion of the crown 34. The size or extent of the pleats or pleats may vary. The pleats or pleats 44 in fig. 12B will allow longitudinal flexibility as described above in connection with fig. 12A, but less radial flexibility because crown portion 34 is not raised as in fig. 12A.

As depicted in fig. 12C, elongated graft pleats 46 may be disposed below the crown, with the extent of elongated graft pleats 46 being greater than the extent of pleats or pleats 44. The pleats or pleats 44 may range from about the diameter of the undulating wire 22 to a fraction (e.g., half or less) of the diameter of the undulating wire 22. The elongated graft pleats 46 are generally larger than the diameter of the undulating wire 22. Generally, increasing the extent of the elongate graft pleats 46 increases the flexibility of the stent graft.

As depicted in fig. 12A-12C, the techniques of the present invention are not limited to providing pleats or pleats 44,46 on both sides of crown 34. For example, as depicted in fig. 12D, pleats or pleats 44 (or pleats 46) may be disposed on only one side of crown 34. In other words, the increased stent graft flexibility can be configured to specific needs and configurations.

Fig. 13A-15 depict a stent graft 10 of the present technology in which a stent 20 is disposed substantially between a graft covering 24 and a graft liner 26 and within an unsecured graft portion or lumen 38.

As depicted in fig. 13A, the stent 20 may be disposed between a fused first end 48 and a fused second end 50. Between the two fused graft ends 48,50 is the non-fixed graft portion 38 of the graft covering 26 and the graft lining. The stent 20 of this embodiment will have increased flexibility in the non-fixed graft portion 38 due to the absence or substantial absence of the incorporation of undulating filaments 22 within the graft covering 24 and graft lining 26.

Although fig. 13A depicts stent 20 entirely between the fused ends, the techniques of the present invention are not so limited. For example, as depicted in fig. 13B, portions of the stent 20 may be disposed within the fused ends 48, 50. This embodiment may increase the fixation of the stent 20 within the stent graft 10 while still providing increased flexibility of the stent 2 within the stent graft 10.

Fig. 14 is a cross-sectional view of the stent graft 10 of fig. 13A taken along the 14-14 axis. As depicted in fig. 14, the graft covering 24 and graft lining 26 are secured to one another as shown by the secured graft portion 36.

Fig. 15 is a cross-sectional view of the stent graft 10 of fig. 13A taken along the 15-15 axis. As depicted in fig. 15, the graft covering 24 and graft lining 26 are not secured to one another, as shown by the non-secured graft portion or cavity 38. The stent 20 is disposed within the cavity 38, thereby allowing greater movement and flexibility of the stent 20 compared to prior art stent grafts.

Fig. 16 depicts the increased flexibility of an embodiment of the stent graft 10 when undergoing bending. The pleats or pleats 44,46 below the crown 34 allow the crown 34 to partially lift away from the wall 12 of the stent graft 10 under bending forces. In addition, as shown in fig. 16, the stent undulations become more nested on the bottom or inner radius of the curve, again because the design of the present technology imparts flexibility to the embodiments described herein. Thus, the stent graft 10 has enhanced flexibility while still maintaining the integrity of the graft covering 24 and the graft lining 26.

As depicted in FIG. 17, increased nesting of the stent undulations may also be achieved when the graft 10 is compressed axially or longitudinally along the axis L As the stent graft 10 is compressed, the peaks 28 and valleys 30 (respectively) become more nested or closer together, reflecting the increased flexibility of the stent graft due to factors such as improved graft covering and liner design and the configurations disclosed herein.

Fig. 18A-18D depict various crimping and pleating configurations that may be applied to the graft or may be formed in the graft during compression or bending of the stent graft 10 of the present techniques. Pleats 64 may be simple protrusions of graft covering 24, as depicted in fig. 18A, or may be semi-circular configured pleats 66, as depicted in fig. 18B. As depicted in fig. 18C and 18D, pleats 68 may also be formed or shaped into graft covering 24. Pleats 64, 66 and pleats 68 provide increased flexibility in graft covering 24. Stent graft 10 may include any combination of pleats 64, 66 and pleats 68. Without limiting the generality of the description of the various embodiments of the present technology, generally as used herein, the term "pleat" (e.g., pleats 64, 66) refers to graft coverings or other graft portions or layers that generally form rounded, semi-circular, or curved surfaces when stent graft 10 is in the state depicted in fig. 18A-18B, while the term "pleat" (e.g., pleat 68) refers to graft coverings or other graft portions or layers that generally form more angled, wrinkled, or folded surfaces (e.g., those that form acute angles) when stent graft 10 is in a state such as depicted in fig. 18C-18D. However, it should be understood that either term may be used interchangeably as it relates to this aspect of the present technology.

Fig. 19 depicts the formation of pleats 68 when stent graft 10 is compressed axially or longitudinally. Because of the flexibility of the device, when graft 10 is compressed, pleats 68 form because the graft covering and graft lining are not fully laminated, sintered, or otherwise attached or bonded to one another. Thus, movement of different portions of the stent 20 is not unduly impeded or limited by the graft covering 24 or graft lining 26. Indeed, as noted above, the formation of pleats 68 allows for movement of the components of stent graft 10 in cases where additional graft pleating may be achieved upon longitudinal compression.

Fig. 20 depicts the stent graft 10 of fig. 13A-15 subjected to a bending force. During bending, the pleats of the graft covering 24 are formed under force as indicated by pleats 52, as the stent 20 is free to move within the graft covering 24 and graft lining 24 through the bend. This allows the stent graft 10 to bend about 180 ° or more without a significant reduction in the diameter of the stent graft 10 in any portion of the bend. In other words, patency of the stent graft 10 is maintained during such bending, particularly in the bending region and cross-section of the lumen 18. This results in a higher performance stent graft because blood flow is only slightly reduced, or not reduced at all, during and in clinical applications after deployment. In contrast, as depicted in fig. 21, a stent graft having a stent disposed between laminated or sintered graft layers typical of the prior art forms deformed portions 54 while undergoing a similar degree of bending. The deformed portion 54 corresponds to a lumen with reduced patency and less than ideal clinical performance.

Fig. 22 depicts the stent graft 10 of fig. 13A bent at about 180 °, with a gap of about 6mm or less between portions of the tubular stent graft 10 in the region of the bend. The stent graft 10 is held in a substantially tubular shape by the bend; in particular, in the region 18 of the bend, the lumen 18 of the stent graft 10 remains patent and there is little or no reduction in the cross-sectional diameter of the stent graft 10 or lumen 18. In contrast, as depicted in fig. 23, stent grafts having stents disposed between layers of laminated or sintered graft typical of the prior art form kinks 56 and lumens of reduced patency while experiencing similar degrees of bending.

Figure 24 depicts an embodiment of a ribbon stent graft 10' in accordance with the present technique. During manufacture, the ribbon stent graft 10' may be formed by disposing a wavy filament 22 on a mandrel 58, as shown in fig. 24, the wavy filament 22 having a top strip 60 of polymeric nonwoven graft material disposed on a portion (e.g., a middle portion) of the wavy filament 22 and a bottom strip 62 of polymeric nonwoven graft material disposed below the portion (e.g., the middle portion) of the wavy filament 22. The strips 58, 60 may then be securely disposed to one another by lamination, sintering, adhesive bonding, or the like, as described elsewhere herein. Fig. 25 depicts the ribbon stent graft 10' after removal from the mandrel 58.

Fig. 26 is an enlarged view of a portion of the ribbon stent graft 10' of fig. 25, further detailing the apparatus. Since the bands 60, 62 are provided only on the middle portion of the undulating wire 22, the bands 60, 62 do not form a continuous graft wall. As a result, the ribbons 60, 62 are free to move with the movement of the undulating filaments 22 of the ribbon-like stent graft. In other words, the bands 60, 62 do not unduly inhibit movement of the wavy filaments 22 when moving longitudinally and/or bending.

Fig. 27 and 28 depict the flexibility of the stent graft 10' when undergoing bending, including bending by about 180 ° with a gap of about 6mm as described above and depicted in fig. 27. In fig. 27 and 28, the stent graft 10' is disposed between the graft covering 24 and the graft liner as depicted in fig. 13A-15. The stent graft 10' depicted in fig. 28 is subjected to multiple bending forces resulting in an "S" shaped stent graft 10' with two major bends, as may be experienced when deployed in certain anatomical structures, demonstrating the increased flexibility and patency of the lumen of the stent graft 10' in a challenging configuration.

As depicted in fig. 29 and 30, the ribbon-like stent graft 10 'can also include axial bands 64 disposed along the longitudinal length of the stent graft 10', if desired. Such axial bands 64 will only slightly affect flexibility while providing some increased control of the wavy filaments 22 during longitudinal movement and/or bending, and the design of the present technique provides varying degrees of stability and deployability in vivo.

The graft portions (e.g., cover 24 and liner 26) of the stent grafts 10, 10' of the present technology may include wall portions made of any biocompatible, durable material, including, for example: polyethylene; polypropylene; polyvinyl chloride; polytetrafluoroethylene (PTFE); fluorinated ethylene propylene; fluorinated ethylene propylene; polyvinyl acetate; polystyrene; polyethylene terephthalate; naphthalate derivatives such as polyethylene naphthalate, polybutylene naphthalate, polypropylene naphthalate and butylene naphthalate; polyurethanes, polyureas; silicone rubber; a polyamide; a polyimide; a polycarbonate; polyaldehyde; polyether ether ketone; natural rubber; a polyester copolymer; a silicone resin; styrene-butadiene copolymers; polyethers, such as fully or partially halogenated polyethers; and copolymers and combinations thereof. As used herein, textile materials are woven, knitted, braidedFilament spinning, etc. to form filaments or yarns of the textile graft material. Desirably, the graft material of the present technology is a non-woven graft material, such as a material that is not woven, braided, knitted, filament spun, etc., that may be used with a woven graft. Such useful graft materials may be extruded materials. Particularly useful materials include: porous polytetrafluoroethylene having no discernable node and fibril microstructure and a layer of (wet) stretched PTFE having low or substantially no fluid permeability and comprising a closed-cell microstructure having regions of high density with grain boundaries directly interconnected to grain boundaries of adjacent regions of high density and having substantially no node and fibril microstructure; and porous PTFE having no or substantially no fluid permeability. PTFE layers lacking different parallel fibrils interconnecting adjacent nodes of ePTFE and having no discernable node and fibril microstructure are also useful when viewed at 20,000 times Scanning Electron Microscope (SEM) magnification. A porous PTFE layer that has no or substantially no fluid permeability may have a gurley value greater than about 12 hours (43,200 seconds), or up to a substantially infinite or high to immeasurable gurley value, indicating no measurable fluid permeability. Some PTFE layers that are substantially free of fluid permeability may have a thickness of greater than about 10 at 100cc of air⁶In contrast, embodiments of PTFE layers having low fluid permeability discussed herein may have a Gurley number greater than about 1500 seconds, wherein 100cc of air is used in the test.embodiments of fluid permeable layers of PTFE, such as ePTFE, may have a Gurley air permeability measurement of less than about 10 or 15 Gurley secondsThis patent is incorporated herein by reference in its entirety.

Further, useful PTFE molecules have an average molecular weight of about 2000 to about 5000 tens of thousands or more. Optionally, additives may be added to the PTFE material, such as powdered or liquid color pigments or other resin additives. For example, a fluorine-containing copolymer (e.g., perfluoropropyl vinyl ether modified PTFE) may be added to improve the bondability of the PTFE layer. The additives are typically provided in a mass of less than 2% of the mass of the PTFE material, but may be provided in any amount that produces the desired result.

Although the porous PTFE layer may be configured to have low or substantially zero fluid permeability, the porous PTFE layer 110 still has porosity. The porous PTFE layer can have an average porosity of about 20% to about 80%, specifically about 30% to about 70%. Porosity represents the volume of solid PTFE material as a percentage of the total volume of the PTFE layer. The average pore size in the PTFE layer can be less than about 20 microns, specifically less than about 0.5 microns, for example from about 0.01 microns to about 0.5 microns. The PTFE layer can have an average pore size greater than about 6.0 microns if tissue ingrowth is desired.

The graft portion may be formed of one or more inner layers and one or more outer layers of flexible graft material such as PTFE or ePTFE. In one embodiment, the flexible graft material comprises PTFE, which is substantially porous but does not include a discernable node and fibril structure. The inner and outer layers of graft material may be formed from tubular extrusions, laminated wraps, etc. of multiple layers of one or more graft materials. For some embodiments, the inner or outer layer of the graft material can be permeable (e.g., less than about 10 gurley seconds), semi-permeable (e.g., greater than about 1,500 gurley seconds and optionally less than about 30,000), or substantially impermeable (e.g., greater than about 10 gurley seconds)⁶Gurley seconds).

Fig. 31-34B depict more detail of a stent graft of the present technology. The first radially expandable stent 20, 300 may be interposed between an outer layer (not shown) and an inner layer (not shown) of graft material for the legs. An interposed stent disposed between outer and inner layers of graft material may be formed from an elongate resilient element helically wound with a plurality of longitudinally spaced turns into an open tubular configuration. The helically wound stent may be configured to be self-expanding or radially expandable in an inelastic manner, actuated by an outward radial force from a device such as an inflatable balloon.

The stent or wire portion of the stent graft may be made of stainless steel, nickel titanium alloy (NiTi), such as nitinol, or any other suitable material, including but not limited to cobalt-based alloys (e.g., E L GI L OY), platinum, gold, titanium, tantalum, niobium, and combinations thereof.

As shown in more detail in fig. 31, 32A-32B, 33A-33E, and 34A-B, a generally tubular stent 20, 300 can be provided for a stent graft. The tubular stent 300 comprises a helically wound undulating wire formed into a series of adjacent helical windings 302, which may be made of the materials described above, including resilient metals such as nitinol. The ends 304, 306 of the stent 300 may be secured to adjacent loop portions of the stent at discrete regions. For example, the first end may abut via a first fixation point 308 and the second end may engage at a second fixation point 310, as shown, to avoid exposure of the element ends to the PTFE graft material or possibly patient tissue. In a preferred embodiment, the fixation points 308, 310 are located proximal to the first end 304 and the second end 306, respectively, and there are no other fixation points on the stent 300. That is, adjacent approximately circumferential windings 302 in the stent 300 may be free of interconnected fixation points, except for the helical windings 302 at the first end 304 (which may be referred to as the proximal end 304) and the second end 306 (which may be referred to as the distal end 306), respectively. Any means of fixation may be used including, for example, welding, such as braces and welds. Advantageously, the relative stiffness of the stent is greater than the stiffness of the PTFE graft material to provide beneficial kink resistance.

The wavy wire may be a continuous element that forms a series of helical windings 302 extending from one end 304 of the extension to the other end 306 of the extension. The tubular stent 300 thus has an inner lumen 320 extending therethrough from the first end 304 to the second end 306. The ends 304, 306 of the elongated element may be secured to the adjacent annular member by any suitable means, for example adhesive bonding, welding such as laser welding, soldering, etc. For some embodiments, the stent element may have a transverse dimension or diameter of about 0.005 inches to about 0.015 inches. As can be seen in fig. 32A and 32B, the stent 300 may be tapered or flared. Further, if desired, adjacent helical windings 302 may be arranged 315 such that the adjacent helical winding 302 at one end (either first end 304 or second end 306) has an acute angle formation at a portion of the stent 300 proximal to an end of the stent 300. That is, if desired, the helical winding closest to the end (shown as 302') may have an angle of about 180 ° with respect to the longitudinal axis, while the helical winding immediately adjacent to the helical winding (shown as 302 ") has an angle of less than 180 °. The two helical windings (302' and 302 ") may be attached at the fixation points 308, 310.

Fig. 33A-33E depict various arrangements of helical windings 302 formed from a wavy wire during formation of the stent 300. Adjacent helical windings are depicted as 302A and 302B, but it should be understood that the arrangement depicted in fig. 33A-33E may be applied to each helical winding 302 in the stent 300. Alternatively, the arrangement depicted in fig. 33A-33E may be applied to only some of the helical windings 302 in the stent 300. The undulating wire of stent 300 includes a series of peaks 312 and valleys 314 as the wire is helically wound. The arrangement of the peaks 312 and valleys 314 may vary and may be arranged in any desired manner. In some embodiments, such as the embodiment of fig. 33A, the peaks 312 of one circumferential winding 302A may be substantially aligned with the peaks 312 of an adjacent circumferential winding 302B. As can be seen in fig. 33B, adjacent circumferential windings 302A and 302B may be spaced apart. As can be seen in fig. 33C, adjacent circumferential windings 302A and 302B may be close together. In another embodiment shown in fig. 33D, one peak 312 of one circumferential winding 302B may span two peaks 312 of adjacent windings 302A. In another embodiment shown in fig. 33E, the peaks 312 of one circumferential winding 302A may be substantially aligned with the valleys 314 of an adjacent circumferential winding 302B. Other arrangements of the helical winding 302 are contemplated and will be readily understood by those skilled in the art.

The distance between adjacent windings 302A, 302B may vary along the length of the stent 300, wherein the distance at one end 304 is different than the distance at the second end 306. In each embodiment, there are two distances that should be considered. The first distance X is the distance between the lowest valley (314) of the first winding (302A) and the highest peak (312) of the second winding (302B). The second distance Y is the distance between the highest peak (312) and the lowest valley (314) of the first winding (302A).

There may be X/Y present in the device (or equivalently) Including but not limited to three different relative ratios of these distances X/Y. The first ratio is where X/Y is a relatively large positive number, i.e., there is a relatively large spacing between the distances (X) compared to the distance (Y). The second ratio is where X/Y is a relatively small positive number, i.e., there is a relatively small spacing between the distances (X) compared to the distance (Y). Finally, the third ratio is where X/Y is negative, i.e. the lowest peak of the first winding (302A) falls below the highest peak of the second winding (302B).

The ratio X/Y can be manipulated to obtain desired properties of the stent graft in a localized area. A relatively large X/Y ratio (preferably greater than about 0.5) creates a highly flexible region of the stent graft. Smaller X/Y ratios (preferably from about 0.1 to about 0.5) produce regions of the stent graft with moderate flexibility and moderate radial force. Regions of the stent graft having an even smaller or negative X/Y ratio (preferably less than about 0.1) have relatively high radial forces and relatively little flexibility. The above ranges for X/Y are suitable when the stent height Y is from about one-third to about equal to the diameter of the stent. If Y is greater than this when compared to D, then the range of X/Y ratios referenced above will be reduced. Similarly, if Y is much smaller than the stent diameter D, the above range of values will increase.

Using the principles described above, a stent graft can be configured to have an X/Y ratio that varies along the length to achieve desired properties. For example, if the stent graft is used as an iliac limb in a modular endovascular graft for an Abdominal Aortic Aneurysm (AAA), it may be desirable for the proximal end of the stent graft to have a relatively high radial force to maximize the anchoring force into the aortic body member of the modular system. In this case, the proximal end of the iliac limb may be designed to have a small or negative X/Y ratio, such as-0.5, and Y may be selected, for example, from about one-fifth to one-half of the stent graft diameter. In this region, flexibility is less important than radial force, so a negative X/Y ratio yields the desired properties. In the middle of the stent graft, flexibility becomes important to accommodate the tortuous common iliac arteries that are common in AAA patients. Accordingly, it may be desirable to have a relatively large X/Y ratio, such as about 0.55, to achieve this flexibility. Near the distal end of the stent graft, it may also be desirable to have a greater radial force to help anchor and seal the iliac limb into the iliac aorta of the patient, but not as much as the radial force at the proximal end. In such a case, it may be desirable to have an X/Y ratio near zero or from about-0.1 to about 0.3.

Since the stent is formed as a spiral along the length of the stent graft, the X/Y ratio can be continuously varied to achieve desired properties in various regions of the stent graft having a gradual change without a sharp change along the length. These gradual changes help conform to the vasculature and avoid stress and/or strain concentrations and potential kinks that may result from sharp transitions in mechanical properties along the length of the stent graft.

The stent 300 may include a longitudinal axis (defined generally along the inner lumen 320) and a radial axis perpendicular to the longitudinal axis; wherein the helical winding 302 is wound at an acute winding angle of about 3 degrees to about 15 degrees relative to the radial axis. As can be seen in fig. 32A and 32B, the acute winding angle at a portion of stent 300 proximal to first end 304 is different than the acute winding angle at a portion of stent 300 proximal to second end 306. In some embodiments, the first helical winding 302 at the first end 304 may be perpendicular to the longitudinal axis. Further, it may be desirable for the helical winding 302 at the second end 306 to be perpendicular to the longitudinal axis. The helical windings 302 at the first end 304 and the second end 306 may both be perpendicular to the longitudinal axis, or only one may be perpendicular to the longitudinal axis. The adjacent peak 312 and adjacent valley 314 of the helical winding 302 have a peak height from the apex of the adjacent peak to the base of the adjacent valley. It may be desirable for the peak height at a portion of stent 300 proximal to first end 304 of stent 300 to be different than the peak height at a portion of stent 300 proximal to second end 306 of stent 300.

At least one graft layer may be disposed on the stent 300 having embodiments described herein. The placement of the graft layer can be seen most clearly in fig. 34A, 34B and 30. In some embodiments, an inner graft layer 318 can be disposed on the inner surface of the helically wound stent 300, forming an inner lumen 320. A second graft layer 316 can be disposed on the outer surface of the helically wound stent 300 having embodiments described herein, forming an outer surface. More than one or two layers of graft material may be disposed on the interior or exterior of the helically wound stent 300 as desired. For some embodiments of the stent graft, layers of materials having different properties may be used in combination to achieve the desired clinical performance. For example, some layers of PTFE covering the stent 300 may be permeable, semi-permeable, or substantially impermeable, depending on the desired performance and material properties. Layers 316 and 318 may be applied by a variety of methods and have various configurations as described herein. For example, some layer embodiments may include an extruded tubular structure applied axially over a mandrel or subassembly. Some layer embodiments 316 and 318 may be applied by wrapping the layers circumferentially or wrapping strips or ribbons in an overlapping spiral pattern. For some embodiments, the outer layer 316 may be made of or include a semi-permeable or substantially impermeable PTFE layer, and the inner layer 318 may be made of or include a permeable layer of PTFE.

The stent graft may be made by forming the layers 316, 318 of material together with the helically wound stent 300 on a mandrel, such as a cylindrical mandrel (not shown). Once the innermost layer 316 of the stent graft has been wrapped around the shaped mandrel, a helical nitinol stent, such as helical stent 300, may be placed over the innermost PTFE layer 316 and the underlying mandrel. If desired, one or more additional layers 318 of graft material may be wrapped or otherwise added onto the exterior of the stent 300 described herein. If desired, the outer layer 318 may comprise a low permeability PTFE membrane or a substantially non-permeable PTFE membrane that does not have the conventional node fibril microstructure.

The Graft portion may be made at least in part of Polytetrafluoroethylene (PTFE), which may include expanded polytetrafluoroethylene (ePTFE), particularly the Graft portion may include any number of layers of PTFE and/or ePTFE, including about 2 to about 15 layers, having an uncompressed layer thickness of about 0.003 inch to about 0.015 inch for only one or more soft Graft materials, without support or auxiliary structures such as high strength stents, connector rings, etc. such Graft body sections may also include any alternative high strength soft biocompatible Material suitable for Graft applications, such as DACRON Graft body sections and other components of the Graft assembly (which may be used in any suitable combination for any of the embodiments discussed herein) as described in U.S. patent No. 7,125,464 to Chototov et al, entitled "Method and Apparatus for Manufacturing and Endocaul prosthesis, Inc.; U.S. patent No. 8,728,372 to Chototov et al, entitled" Method and Apparatus for Manufacturing and Endokura et al, "incorporated by weight patent No. L, and general names of U.S. patent No. 14,539 for Manufacturing and U.S. patent application Ser. L, entitled" and grade and incorporated by weight et al, Inc.; patent No. 369, entitled "Manufacturing and patent No. cited in U.S. A. A patent for Manufacturing and A. 369, entitled Method and A.

Additional details of the above-described graft assembly including modular components may be found in U.S. patent application publication No. 2013/0261734 entitled "Advanced kit resist Stent-graft" to Young et al, which is incorporated herein by reference in its entirety. Further details of grafts and stent-graft assemblies comprising Modular components may be found in U.S. patent application publication No. 2015/0088244 entitled "Tandem Modular Endograft" to Chobotov, which is incorporated herein by reference in its entirety.

Various methods and Delivery systems for delivering devices into a patient include those described in U.S. patent application publication No. 2009/0099649 to Chobotov et al, entitled "Modular Vascular Graft for L ow Profile Percutaneous Delivery," the contents of which are incorporated herein by reference in their entirety for intravascular methods, access to the vasculature of a patient may be achieved by performing an arteriotomy or cutting into the femoral artery of a patient or by other common techniques (e.g., Percutaneous tenoning techniques).

The systems, devices, methods, and techniques of the present technology may be used with systems, devices, methods, and techniques for treating abdominal aortic aneurysms. Details of endovascular prostheses and/or graft extensions that may be used to treat abdominal aortic aneurysms may be found in commonly owned U.S. patent nos. 6,395,019; 7,081,129 No; 7,147,660 No; 7,147,661 No; 7,150,758 No; 7,615,071 No; 7,766,954 and 8,167,927, and commonly owned U.S. patent application publication No. 2009/0099649, the contents of all of which are incorporated herein by reference in their entirety. Details of the manufacture of such endovascular prostheses can be found in commonly owned U.S. patent nos. 6,776,604; 7,090,693 No; 7,125,464 No; 7,147,455 No; 7,678,217 and 7,682,475, the contents of all of which are incorporated herein by reference in their entirety. Useful inflation materials for use in inflatable implants can be found in commonly owned U.S. patent application publication nos. 2005/0158272 and 2006/0222596, the contents of all of which are incorporated by reference herein in their entirety. Additional details of suitable intravascular delivery systems for abdominal aortic aneurysms include, but are not limited to, U.S. patent nos. 9,233,015, 9,066,828, and 9,132,025, the contents of which are incorporated herein by reference in their entirety.

While various embodiments of the present technology have been particularly shown and/or described herein, it will be appreciated that modifications and variations of the present technology may be made by those skilled in the art without departing from the spirit and intended scope of the present technology. Furthermore, any of the embodiments or aspects of the invention as described in the claims or in the specification may be used with each other without limitation.

The following embodiments or aspects of the invention or of the inventive technique may be combined in any manner and combination and are within the scope of the invention as follows: