bracket

Abstract

A stent includes a wire woven into a tubular fence to form a stent body, a plurality of tubular units connected around a longitudinal central axis of the stent body, and a plurality of connection sites configured to connect adjacent tubular units of the plurality of tubular units and arranged along a plurality of circumferences with respect to the longitudinal central axis of the stent body. The plurality of circumferences includes a first circumference having a first radius and a second circumference having a second radius, and the first radius is different in length from the second radius.

Description

[0001] Related Application Data

[0002] This application is based on and claims priority to U.S. Provisional Application No. 63 / 149,686, filed on February 16, 2021, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present invention relates to a stent, and more particularly, to a self-expanding stent. BACKGROUND

[0004] In recent years, stent placement has been used to expand and maintain the lumen of a tubular organ by placing a stent made of a wire or the like in a stenosed or occluded site in the lumen of the tubular organ of a patient.

[0005] Generally, a stent will have an unexpanded (reduced or closed) diameter for placement and an expanded (open) diameter after placement in a blood vessel or duct. Some stents are self-expanding; some stents mechanically expand using a radially outward force from within the stent, such as by inflation of a balloon; some stents, known as hybrid stents, have one or more features in common with both self-expanding and mechanically expandable stents.

[0006] Figure 1A is a perspective side view schematically illustrating a portion of a conventional self-expanding stent formed by weaving a wire into a cylindrical stent. The conventional stent includes a plurality of tubular cells connected by a plurality of connecting portions arranged along a circumferential line defined by the cylindrical shape of the stent. For illustrative purposes, Figure 1A only two such tubular cells connected at a plurality of connecting sites (A1-A5 shown in Figure 1A are shown. Figure 1B is a front view (or cross-sectional view) schematically illustrating a tubular cell of Figure 1A the first wire in Figure 1B . As shown, the plurality of circumferential segments 1-11 are arranged along one circumferential line (the first line in Figure 1A ). Although not labeled in Figure 1B , there are also a plurality of connecting sites and a plurality of circumferential segments arranged along another circumferential line (the second line in Figure 1A ).

[0007] Figure 2A and Figure 2Bis a front view (or cross-sectional view) schematically showing a conventional stent in a delivery configuration. Since the stent must be delivered to a desired body site in an unexpanded diameter state (a reduced diameter state) via an inner sheath 50 and covered by an outer sheath 60. Once reaching the desired body site, the outer sheath 60 is pulled back to expose the stent so that the stent can be expanded and implanted in a body lumen. As shown in Figure 2A and Figure 2B When the conventional stent is reduced in diameter to be accommodated between the inner sheath 50 and the outer sheath 60, an external force is required to deform the wire by pushing adjacent circumferential segments 1-11 of the wire against each other. As a result, the stent is accommodated disorderly or cannot be uniformly accommodated, so that the space between the inner sheath 50 and the outer sheath 60 becomes dense or sparse depending on the location of the connection site, which results in an increase in radial thickness due to the disorderly overlapping of the wire at the connection site. This situation also results in difficulty in recapturing the stent in the body. SUMMARY

[0008] Accordingly, the present disclosure relates to a stent that substantially obviates one or more problems due to limitations and disadvantages of the related art stent delivery devices and systems.

[0009] An object of the present disclosure is to provide a stent including a wire woven into a tubular fence to form a stent body, a plurality of tubular units connected around a longitudinal center axis of the stent body, and a plurality of connection sites configured to connect adjacent tubular units of the plurality of tubular units and arranged along a plurality of circumferences with respect to the longitudinal center axis of the stent body. The plurality of circumferences includes a first circumference having a first radius and a second circumference having a second radius, and the first radius is different in length from the second radius.

[0010] Another object of the present disclosure is to provide a stent including a wire woven into a tubular fence, a first intertwined connection part formed by hooking a first bend part with a second bend part of the wire, and a second intertwined connection part formed by hooking a third bend part with a fourth bend part of the wire. The first bend part is adjacent to the third bend part in a circumferential direction, and the second bend part is adjacent to the fourth bend part in the circumferential direction. A first radial distance between the first intertwined connection part and a longitudinal center axis of the stent is different from a second radial distance between the second intertwined connection part and the longitudinal center axis of the stent.

[0011] Additional features and advantages will be set forth in the description which follows, and in part will be apparent from the description, or can be learned by practice of the application. The objectives and other advantages of the disclosed stent, as well as stent delivery devices and systems, will be realized and attained by the structure particularly pointed out in the written description and claims thereof as well as the appended drawings. Attached Figure Description

[0012] The following detailed description of the preferred embodiments can be read in conjunction with the accompanying drawings, in which the same numbers represent the same elements, wherein:

[0013] Figure 1A This is a schematic perspective view of a portion of a conventional self-expanding stent. Figure 1B yes Figure 1A The front view (or cross-sectional view).

[0014] Figure 2A and Figure 2B This is a schematic illustration of the conveyor structure. Figure 1A A cross-sectional view of a conventional support structure.

[0015] Figure 3 This is a schematic diagram illustrating the overall structure of a support according to an exemplary embodiment.

[0016] Figure 4 It is a projection of a circular surface onto a plane. Figure 3 Another view of a portion of the support structure.

[0017] Figure 5 An exemplary embodiment of a braided pattern of multiple tubular units of a support is shown, according to an exemplary embodiment.

[0018] Figure 6 It shows the basis Figure 5 An exemplary woven pattern in which a tubular unit located on a first longitudinal side is connected from a second longitudinal side to another tubular unit.

[0019] Figure 7 yes Figure 4 An enlarged view of region P1, indicated by the dashed line.

[0020] Figure 8A This is a schematic perspective side view of a portion of a self-expanding support formed by braiding wires into a tubular fence according to an exemplary embodiment. Figure 8B It is a schematic diagram. Figure 8A A front view (or cross-sectional view) of the structural configuration of multiple circumferential segments.

[0021] Figure 9 It is a schematic front view (or cross-sectional view) of the support in the conveying configuration.

[0022] Figure 10 This is a schematic diagram illustrating an exemplary construction in which steps (e.g., variations in radial distance) are formed between adjacent entanglements of a support according to an exemplary embodiment.

[0023] Figure 11 is a graph showing the radial force (N) as a function of the diameter (mm) of the stent as a stent for a conventional stent and a stent according to an exemplary embodiment.

[0024] Figure 12 is a table illustrating experimental results of a stent according to an exemplary embodiment.

[0025] Figure 13 is a front view schematically illustrating a stent according to one exemplary embodiment including a two-step configuration.

[0026] Figure 14 is a front view schematically illustrating a stent according to one exemplary embodiment including a three-step configuration.

[0027] Figures 15A-15E is a graph schematically illustrating an exemplary pattern of steps present between stent entanglements in both the circumferential direction and the longitudinal central axis direction according to one exemplary embodiment.

[0028] In all the drawings, the dimensions of the respective constituent elements are appropriately adjusted for the sake of clarity. For ease of viewing, in some cases, only some of the features in the drawings are labeled with reference numerals. DETAILED DESCRIPTION

[0029] Figure 3 is a graph schematically partially illustrating the configuration of a stent 100 according to an exemplary embodiment. Figure 4 is a plan view of the stent 100 expanded in the circumferential direction. Figure 3 Figure 3 The stent 100 in is a self-expanding stent formed by braiding wire into a cylindrical tubular fence. The stent 100 is generally placed within a lumen of the digestive system such as the bile duct, esophagus, duodenum, small intestine, and large intestine, and is mainly used for the purpose of expanding and maintaining the lumen.

[0030] The stent 100 in this exemplary embodiment is an uncoated stent, meaning that the stent 100 is not coated with a film or the like as found in so-called covered stents in which a resin film or the like is coated on the outer peripheral surface side. However, the stent 100 can also be used as a covered stent by being covered with a resin film or the like.

[0031] As shown in Figure 3 and Figure 4 , the stent 100 can include a plurality of tubular units 40 and a plurality of connection sites 20 connecting the plurality of tubular units 40 together to form the main body of the stent 100. The plurality of tubular units 40 are arranged (in the longitudinal central axis direction L) around the axis along the longitudinal central axis X of the stent in the longitudinal central axis direction L (in the longitudinal central axis direction L) in the Figure 3 Figure 4 ​​). Any adjacent tubular units 40 are connected by a plurality of connection sites 20.

[0032] In this exemplary embodiment, as will be explained in detail below, the plurality of connection sites 20 are also referred to as entanglement connection sites, since each entanglement connection site is formed by hooking two bent portions of the wire.

[0033] In the following description, the side of the axial direction L of the stent 100 on the side of the distal end portion is also referred to as "first axial direction Dl", and the other side of the axial direction L of the stent 100 on the side of the proximal end portion is also referred to as "second axial direction D2".

[0034] As a part of the tubular fence, each tubular unit 40 is formed in a circular shape with a mesh on the outer peripheral surface thereof by extending the wire in the circumferential direction C in a state of being repeatedly bent and intersected.

[0035] Each tubular unit 40 includes a plurality of first bent portions 14 in which the wire is bent toward the first axial direction Dl, a plurality of second bent portions 12 in which the wire is bent toward the second axial direction D2, and a plurality of intersection portions 13 in which the wires intersect each other, in particular, in a straight line.

[0036] In this exemplary embodiment, the plurality of first bent portions 14 are arranged along the circumferential direction C. Each first bent portion 14 is a convex portion in which the wire extending in the circumferential direction C is bent backward in the longitudinal central axis direction L and convex toward the first direction Dl. On the other hand, the plurality of second bent portions 12 are arranged along the circumferential direction C. Each second bent portion 12 is a convex portion in which the wire extending in the circumferential direction C is bent backward in the longitudinal central axis direction L and convex toward the second direction D2.

[0037] Each connection site 20 is a portion in which adjacent tubular units 40 are connected in the longitudinal central axis direction L, and is formed by hooking the first bent portion 14 of the tubular unit 40 on the second direction D2 side to the second bent portion 12 of the tubular unit 40 on the first direction Dl side. Therefore, the connection site 20 is also referred to as an entanglement connection site. Further, in each entanglement connection site 20, the first bent portion 14 and the second bent portion 12 intersect in a "hook shape" in the radial direction and the longitudinal central axis direction, so that the adjacent tubular units 40 are connected in a state of being inseparable but relatively movable.

[0038] In the intersection portion 13, the wires generally intersect and overlap each other (in the radial direction) in a straight line, and at the point of intersection / overlap, one wire is radially inward with respect to the other wire. The intersection portion 13 can be formed between adjacent entanglement connection sites 20 along the circumferential direction C, and / or can be formed between adjacent entanglement connection sites 20 in the longitudinal central axis direction L.

[0039] Figure 5 This is a diagram illustrating an exemplary embodiment of how the tubular unit 40 is woven. The tubular unit 40 is manufactured using a manufacturing jig. The manufacturing jig may be formed from a cylindrical body and a plurality of pins P standing upright on the outer peripheral surface of the body. Although Figure 5 Not shown, but multiple pins P include a first group of pins and a second group of pins. Each first group of pins includes pins that will be adjusted according to... Figure 10 The spacer 82 is described later. Each second set of pins does not have a spacer 82 and is in direct contact with the outer peripheral surface of the body.

[0040] Figure 5 This is a schematic view illustrating the outer peripheral surface of the main body of the manufacturing fixture projected onto a plan view. For illustrative purposes, Figure 5 Only two rows of pins P arranged around the circumferential direction C are shown.

[0041] like Figure 5 As shown, the wire forming the tubular unit 40 extends obliquely from the starting position S along the circumferential direction C, and repeatedly forms a first bend 14 and a second bend 12. The wire is formed into a first loop along the circumferential direction C, and then into a second loop along the circumferential direction C. Figure 5 Part ① shown in the diagram is then used to complete the third loop, ending at position E. Figure 3 Part ② shown.

[0042] The first coil of wire is Figure 5 The middle is represented by a dashed line, from Figure 5 The bottom S extends to Figure 5 The part shown at the top ①.

[0043] The second coil of wire is Figure 5 The middle is represented by a solid line, from Figure 5 The bottom part ① extends to Figure 5 The portion ② shown at the top. The second coil of wire extends in an inclined direction along the circumferential direction C, repeatedly forming a first bend 14 and a second bend 12. The first bend 14 formed by the wire on the second coil is formed between the first bend 14 formed by the wire on the first coil. The second bend 12 formed by the wire on the second coil is formed between the second bend 12 formed by the wire on the first coil. The second coil of wire forms a straight intersection 13 that intersects with the first coil of wire.

[0044] The wire on the third circumference (made by) Figure 5 From Figure 5The single-dot line (indicated by the portion 2 of the bottom of the circle) extending to the point E indicates that the wire formed on the third coil extends in the oblique direction along the circumferential direction C, and repeatedly forms the first curved portion 14 and the second curved portion 12. The first curved portion 14 formed by the wire formed on the third coil is formed between the first curved portion 14 formed by the wire formed on the first coil and the first curved portion 14 formed by the wire formed on the second coil. The second curved portion 12 formed by the wire formed on the third coil is formed between the second curved portion 12 formed by the wire formed on the first coil and the second curved portion 12 formed by the wire formed on the second coil.

[0045] The third coil wire forms a straight line intersection portion 13 intersecting the straight line intersection portion 13 of the first coil wire and the second coil wire. After the third coil is made along the circumferential direction C, the wire is braided to the end point E.

[0046] The end portions of the wire located at the start position S and the end point E can be connected by using a joining method such as caulking, laser welding, brazing, or the like. In the present embodiment, the wire joins the end portions of the second curved portions 12. However, in consideration of the possibility of stress concentration occurring at the end portions, the wire can be joined at the straight line portions instead of the end portions of the first curved portions 14 and the end portions of the second curved portions 12. Figure 5

[0047] The wire can be a super-elastic alloy in which the main material is NiTi. The super-elastic alloy containing NiTi as the main material does not permanently deform when braided, but memorizes the braided shape by applying heat treatment in the braided state.

[0048] As shown in FIG. 1, as described above, the braided tubular unit 40 constitutes two intersection portions 13 on the wire segment of the wire connecting the first curved portion 14 and the second curved portion 12. The tubular unit 40 of the present application is not limited to this configuration, but the intersection portions 13 can be formed at any appropriate portions depending on the type or configuration of the stent. Figure 5

[0049] An exemplary braiding method is shown in which one tubular unit 40 located on the first direction Dl side (hereinafter, "tubular unit 40A") is connected to a braided tubular unit 40 (hereinafter, referred to as "tubular unit 40B") from the second direction D2 side. As shown in FIG. 6, the tubular unit 40A is indicated by a double-dot line. Figure 6 Figure 6 When the tubular unit 40B is manufactured using a manufacturing jig, a portion of the pins used to manufacture the tubular unit 40A is shared as shown in FIG. 7. Specifically, in the present embodiment, among the pins P arranged in two rows along the circumferential direction C, the pins P arranged in one row on the second direction D2 side are shared.

[0050] When the tubular unit 40B is manufactured using a manufacturing jig, a portion of the pins used to manufacture the tubular unit 40A is shared as shown in FIG. 7. Specifically, in the present embodiment, among the pins P arranged in two rows along the circumferential direction C, the pins P arranged in one row on the second direction D2 side are shared. Figure 6 Figure 6

[0051] As shown in FIG. 1, as described above, the braided tubular unit 40 constitutes two intersection portions 13 on the wire segment of the wire connecting the first curved portion 14 and the second curved portion 12. The tubular unit 40 of the present application is not limited to this configuration, but the intersection portions 13 can be formed at any appropriate portions depending on the type or configuration of the stent. Figure 6 ​​​​As shown, the wire forming the tubular unit 40B extends obliquely from the start position S along the circumferential direction C and repeatedly forms the first bend 14 and the second bend 12.

[0052] Figure 7 is an enlarged view of the area P1 shown by the dotted line in Figure 4 . When the first bend 14 is formed, the wire forming the tubular unit 40B intersects the second bend 12 of the tubular unit 40A in a "hook-like" manner in the radial and longitudinal directions to form the entanglement 20.

[0053] As with the tubular unit 40A, after making the third turn along the circumferential direction C, the wire is knitted to the end point E. The two ends of the wire located at the start position S and the end point E are connected by using a joining method such as caulking, laser welding, brazing, or the like.

[0054] The tubular unit 40A and the tubular unit 40B are connected by the entanglement connection site 20 so that the tubular unit 40A and the tubular unit 40B are not separable but are relatively movable. With this configuration, the tubular unit 40A and the tubular unit 40B can be connected without adding a new connection member.

[0055] The other tubular units 40 can all be connected to the adjacent tubular units 40 by the entanglement connection site 20 in the same manner as the tubular unit 40A and the tubular unit 40B are connected by the entanglement connection site 20. By connecting all of the tubular units 40, the main body of the stent 100 is thereby formed.

[0056] Figure 8A is a perspective side view schematically illustrating a portion of a self-expanding stent 100 formed by knitting a wire into a cylindrical tubular fence according to one example embodiment. The stent 100 includes a plurality of tubular units 40 connected by a plurality of entanglement connection sites 20 arranged along circumferential lines of the main body of the stent 100. As will be explained in detail below, these circumferential lines include circumferential lines such as a first line and a second line in Figure 8A , which are arranged parallel to each other in the longitudinal center axis direction L, and also include circumferential lines C1-C4 in Figure 14 , which are arranged parallel to each other in the radial direction of the stent 100 with respect to the longitudinal center axis X of the stent 100 as concentric circles.

[0057] For the purpose of explanation, Figure 8A only two such tubular units 40 connected by a plurality of entanglement connection sites 20 are shown. The difference between the stent 100 and a conventional stent is shown in Figure 8B , not in Figure 8A . Figure 8B is a perspective view schematically illustrating Figure 8Ais a front view (or cross-sectional view) schematically illustrating a configuration of a plurality of entanglement connection sites 20. In Figure 8B the figure, reference numeral 1 indicates an element representing an intersection 13(1) formed between two adjacent entanglement connection sites 20. Reference numerals 2-11 indicate ten elements representing respective entanglement connection sites 20(2) to 20(11).

[0058] As Figure 8B shown, the plurality of entanglement connection sites 20(2)-20(11) are configured along two concentric circumferential lines Cl and C2, the centers of which are located on the longitudinal center axis X of the stent 100. Since the radius Rl of the circumferential line Cl is greater than the radius R2 of the circumferential line C2, there is a gap between the circumferential line Cl and the circumferential line C2. In this exemplary embodiment, five entanglement connection sites 20(3), 20(5), 20(7), 20(9), and 20(11) are configured along the circumferential line Cl and five entanglement connection sites 20(2), 20(4), 20(6), 20(8), and 20(10) are configured along the circumferential line C2. Any two adjacent entanglement connection sites 20 are configured along the respective circumferential lines Cl and C2, respectively. The intersection 13 can be configured on the circumferential line Cl or the circumferential line C2.

[0059] In the radial direction, the five entanglement connection sites 20(3), 20(5), 20(7), 20(9), and 20(11) do not overlap with the five entanglement connection sites 20(2), 20(4), 20(6), 20(8), and 20(10). Thus, there is a step Sl between any two adjacent entanglement connection sites 20(2)-20(11). The radius Rl is equal to a first distance between each of the entanglement connection sites 20(3), 20(5), 20(7), 20(9), and 20(11) and the longitudinal center axis X. The radius R2 is equal to a second distance between each of the entanglement connection sites 20(2), 20(4), 20(6), 20(8), and 20(10) and the longitudinal center axis X. As will be described later, the difference between the first distance and the second distance, or the difference between the radii Rl and R2, can be set as the height H of the step Sl between two adjacent entanglement connection sites 20, as Figure 10 shown.

[0060] Figure 9 is a front view (or cross-sectional view) schematically illustrating the stent 100 in a delivery configuration. Since the stent 100 has to be delivered to a desired body site via the inner sheath 50 in a state where the diameter is reduced by external radial force so that the stent 100 can be compressed to an unexpanded diameter state covered by the outer sheath 60. Once reaching the desired body site, the outer sheath 60 is pulled back to expose the stent 100 so that the stent 100 can self-expand and be implanted into the target region of the lumen. As Figure 9As shown, during the transport operation where the stent 100 must be housed between the inner sheath 50 and the outer sheath 60, an external radial force is required to push the entangled connection portion 20 of the stent 100 to reduce the diameter of the stent 100. Since the step S1 is formed between any two adjacent entangled connection portions 20, each pair of adjacent entangled connection portions 20 is pushed into its corresponding position along different circumferences. Therefore, any two adjacent entangled connection portions 20 are prevented from pushing against each other, thus avoiding a chaotic configuration of the entangled connection portions 20. With this configuration, the stent 100 can be housed uniformly because the space between the inner sheath 50 and the outer sheath 20 can be used evenly and orderly regardless of the location of the entangled connection portions 20. As a result, this configuration facilitates the release and recapture of the stent 100 within the body.

[0061] Figure 10 This diagram schematically illustrates an exemplary construction in which steps are formed between adjacent entangled connection portions 20 of the support 100 according to the exemplary embodiment. As described above, the support 100 is formed by connecting a plurality of tubular units 40 along the longitudinal central axis direction L. Figure 10 As shown, the support 100 having multiple tubular units 40 can be manufactured using a manufacturing fixture, which includes a cylindrical body 80 and multiple pins P erected on the outer peripheral surface 81 of the body 80.

[0062] like Figure 10 As shown, the entangled connection portions 20(1) and 20(2) are formed adjacent to each other along the circumferential direction C. The wire forming the entangled portion 20(1) is entangled around pin 71, which is one of the second set of pins, and the wire forming the entangled portion 20(2) is entangled around pin 72, which is one of the first set of pins. The entangled portion 20(1) is arranged to be in direct contact with the outer peripheral surface 81 of the body 80, while the entangled portion 20(2) is arranged on the outer peripheral surface 81 with a spacer 82 in between, such that the entangled portion 20(2) can be radially outward than the entangled portion 20(1). In other words, the spacer 82 is arranged between the entangled portion 20(2) and the outer peripheral surface 81 of the body 80. The spacer 82 is configured to create a radial step S1 (or radial offset) between the entangled connection portions 20(1) and 20(2). Figure 8B (Middle). The height H of the spacer 82 is set to the height of the step S1 formed between the entangled connection portions 20(1) and 20(2).

[0063] In this exemplary embodiment, the height H of step Sl is set to be at least equal to or greater than the radius of the wire used to manufacture the bracket 100. For example... Figure 8B and Figure 9As shown, the steps S1 formed between any adjacent entanglement connection sites 20 are configured to provide a spacing such that, when the stent is in the delivery configuration, the entanglement connection sites 20(2), 20(4), 20(6), 20(8) and 20(10) can be compressed to a position along the circumference C2 proximate to the inner sheath 50, while the corresponding adjacent entanglement connection sites 20(3), 20(5), 20(7), 20(9) and 20(11) can be compressed to a position along the circumference C1 proximate to the outer sheath 60. Thus, in the delivery (diameter-reduced) configuration, when the stent 100 is housed between the inner sheath 50 and the outer sheath 60, the adjacent entanglements do not push against each other. With this configuration, the stent 100 can be orderly and uniformly housed between the inner sheath 50 and the outer sheath 60 during delivery or recapturing operations.

[0064] Figure 11 is a graph illustrating the relationship between the radial force and the diameter of a conventional stent compared to the stent according to the present embodiment, Figure 12 is a table showing the experimental results of the stent according to the exemplary embodiment. In Figure 11 , the line 200 represents the relationship between the expanding radial force and the diameter of a conventional stent when the conventional stent is released, and the line 205 represents the relationship between the anti-diameter-reducing force (radial force resisting diameter reduction) and the diameter of the conventional stent when the conventional stent is housed between the inner sheath and the outer sheath of a delivery device. The line 210 represents the relationship between the expanding radial force and the diameter of the stent 100, and the line 215 represents the relationship between the anti-diameter-reducing force and the diameter of the stent 100.

[0065] As described above, since the conventional stent does not have a radial offset configuration that forms at least one step between any adjacent entanglements, a greater radial force is required to release and recapture the conventional stent. Thus, as Figure 11 and Figure 12 shown, an anti-diameter-reducing force of 89.9 Newtons (N) is required to maintain the conventional stent inside a delivery device when the conventional stent is housed in the delivery configuration. In contrast, an anti-diameter-reducing force of 54.8 (N) is required to house the stent 100 between the inner sheath 50 and the outer sheath 60. The difference is 35.1 (N) or 39%.

[0066] On the other hand, an expanding force of 89.9 (N) is required to fully expand the conventional stent when the conventional stent is in the released configuration in which the conventional stent self-expands into a target site. In contrast, the stent 100 only requires an expanding force of 54.8 (N) to fully expand into a target site. The difference is 35.1 (N) or 39%. With the radial offset configuration, the stent 100 is easily released and recaptured.

[0067] As described above, in the radially offset configuration of the stent 100, a step is formed in the radial direction between any adjacent entanglements arranged along the circumferential direction C. Further, a step can be formed in the radial direction between any adjacent entanglements in the longitudinal central axis direction L. Further, the present application is not limited to the above-described configuration, and the stent 100 can have a multi-step configuration in the entanglements along the circumferential direction C and / or in the longitudinal direction L.

[0068] Figure 13 is a front view schematically illustrating a stent 100a including a two-step configuration according to one example embodiment, Figure 14 is a front view schematically illustrating a stent 100b including a three-step configuration according to one example embodiment.

[0069] In Figure 13 the example embodiment shown. The stent 100a is the same as the above-described stent 100 except that the stent 100a includes the intersection 1' and a plurality of entanglements 2'-11' arranged along at least three circumferences CI-C3. The three circumferences CI-C3 are concentric circles having different radii. In this example embodiment, the intersection 1' and three entanglements 2', 6', and 10' are arranged along the circumference CI; five entanglements 3', 5', 7', 9', and 11' are arranged along the circumference C2; and two entanglements 4' and 8' are arranged along the circumference C3.

[0070] As Figure 13 shown, the multi-step configuration of the stent 100a includes at least two steps SI and S2 formed between two entanglements adjacent to each other but arranged along different circumferences CI to C3, respectively. Since the circumferences CI to C3 are concentric circles having different radii, both steps SI and S2 are formed by arranging any adjacent entanglements along different circumferences so as to produce a radial offset. For example, the step SI between adjacent entanglements 2' and 3' is formed by arranging the adjacent entanglements 2' and 3' along the respective circumferences CI and C2 such that the entanglement 2' is located radially outward of the entanglement 3'. Further, the step S2 between adjacent entanglements 3' and 4' is formed by arranging the adjacent entanglements 3' and 4' along the respective circumferences C2 and C3 such that the entanglement 3' is located radially outward of the entanglement 4'.

[0071] The intersection 1' is arranged on the circumference line CI, but can also be arranged along the circumference line C2 or C3.

[0072] In Figure 14In the illustrated example embodiment, the stent 100b is identical to the stent 100 described above except that the stent 100b includes a plurality of entanglements 1" - 11" arranged along at least four circumferences CI - C4. The four circumferences CI - C4 are concentric circles and have different radii. In this example embodiment, two entanglements 1" and 7" are arranged along the circumference CI; three entanglements 2", 6" and 11" are arranged along the circumference C2; four entanglements 3", 5", 8" and 10" are arranged along the circumference C3; and two entanglements 4" and 9" are arranged along the circumference C4.

[0073] As Figure 14 illustrated, the multi-step configuration of the stent 100b includes at least three steps SI - S3 formed between any two entanglements 1" - 11" arranged adjacent to each other but along respective two of the different circumferences CI - C4. Since the circumferences CI - C4 are concentric circles having different radii, the three steps SI - S3 are each formed by arranging any adjacent entanglements along different circumferences so as to create a radial offset. For example, the step SI between the adjacent entanglements 1" and 2" is formed by arranging the adjacent entanglements 1" and 2" along respective circumferences CI and C2 such that the entanglement 1" is located radially outward relative to the entanglement 2". The step S2 between the adjacent entanglements 2" and 3" is formed by arranging the adjacent entanglements 2" and 3" along respective circumferences C2 and C3 such that the entanglement 2" is located radially outward relative to the entanglement 3". Further, the step S3 between the adjacent entanglements 3" and 4" is formed by arranging the adjacent entanglements 3" and 4" along respective circumferences C3 and C4 such that the entanglement 3" is located radially outward relative to the entanglement 4".

[0074] Figures 15A-15E is a diagram schematically illustrating an example pattern of steps between entanglement connections of a stent in both circumferential and longitudinal central axis directions according to one example embodiment. Figures 15A-15E Both illustrate a tubular stent cut along a longitudinal axis direction (arrow direction) and unfolded as a plan view.

[0075] The dashed lines and double-dot chain lines are wires that make up the stent. The points N1 circled by the dashed lines are entanglement connection nodes where the dashed lines and double-dot chain lines are entangled. When the stent is in a tubular state or fully self-expanded state, the distance between the longitudinal central axis of the stent and the points N1 circled by the dashed lines is greater than the distance between the longitudinal central axis and the points N2 not circled by the dashed lines.

[0076] Figures 15A-15EVarious exemplary configuration patterns of the point N1 (winding joint) circled by dashed lines are shown. When a tubular stent is placed in the lumen of a body, the stent may undesirably shrink. In this case, the function of the stent in ensuring the lumen space is compromised. Therefore, it is important to vary the configuration pattern and the number of points N1 circled by dashed lines according to the stent material and the properties of the lumen, so that the ease with which the tubular stent shrinks can be appropriately adjusted, thereby avoiding undesirable shrinkage.

[0077] Using the above-described structure, stents 100, 100a, or 100b can be housed in a delivery system in a reduced-diameter state and transported to the affected area where stenosis or occlusion has occurred. Upon release from the delivery system, stents 100, 100a, or 100b expand their diameter through self-expansion, thereby widening stenosis and occlusion. Because stents 100, 100a, or 100b have the aforementioned structural configuration, delivery and recapture operations of stents 100, 100a, or 100b are facilitated.

[0078] Stents 100, 100a, and 100b can be made of any suitable implantable material, including but not limited to nitinol, stainless steel, and other materials. Cobalt-based alloys, platinum, gold, titanium, tantalum, niobium, polymeric materials, and combinations thereof. Examples of useful and non-limiting polymeric scaffold materials include poly(L-lactide) (PLLA), poly(D,L-lactide) (PLA), poly(glycolic acid) (PGA), poly(L-lactide-co-D,L-lactide) (PLLA / PLA), poly(L-lactide-co-glycolic acid) (PLLA / PGA), poly(D,L-lactide-co-glycolic acid) (PLA / PGA), poly(glycolic acid-co-trimethylene carbonate) (PGAIPTMC), polydioxanone (PDS), polycaprolactone (PCL), polyhydroxybutyrate (PHBT), poly(phosphazene)poly(D,L-lactide-co-caprolactone) PLA / PCL, poly(glycolic acid-co-caprolactone) (PGAIPCL), poly(phosphate esters), etc.

[0079] Furthermore, stents 100, 100a, and 100b and portions thereof may have a composite construction. For example, stents 100, 100a, and 100b may have an inner core made of tantalum, platinum, iridium, or a combination thereof, and an outer member or outer layer made of nitinol to provide composite wiring to improve radioactivity or visibility. Alternatively, stents 100, 100a, and 100b may be made of nitinol.

[0080] In addition, the stents 100, 100a and 100b can be treated with any known or useful bioactive or pharmaceutical agent, including but not limited to: anti-thrombogenic agents (such as heparin, heparin derivatives, urokinase, and PPack (dextrophenylalanine proline arginine chloromethylketone); anti-proliferative agents (such as enoxaparin, hirudin, or monoclonal antibodies capable of blocking smooth muscle cell proliferation, as well as angiopeptin and acetylsalicylic acid); anti-inflammatory agents (such as dexamethasone, prednisolone, corticosterone, budesonide, estrogen, sulfasalazine, and mesalamine); antineoplastic / anti-proliferative / anti-miotic agents (such as paclitaxel, 5-fluorouracil, cisplatin, vinblastine, vincristine, epothilones, endostatin, angiostatin and thymidine kinase inhibitors); anesthetic agents (such as lidocaine, bupivacaine and ropivacaine); anti-coagulants (such as D-Phe-Pro-Arg chloromethylketone, an RGD peptide-containing compound, heparin, anti-thrombin antibodies, anti-thrombotic antibodies, platelet receptor antagonists, anti-coagulants agents such as water soluble heparin derivatives, prostaglandin inhibitors, platelet inhibitors and snake venom agents); vascular cell growth promoters (such as growth factor inhibitors, growth factor receptor antagonists, transcriptional activators, and translational promoters); vascular cell growth inhibitors (such as growth factor inhibitors, growth factor receptor antagonists, transcriptional repressors, translational repressors, replication inhibitors, inhibitory antibodies, antibodies directed against growth factors, bifunctional molecules consisting of a growth factor and a cytotoxin, bifunctional molecules consisting of an antibody and a cytotoxin); cholesterol-lowering agents; vasodilating agents; and agents which interfere with endogenous vascoactive mechanisms.

[0081] The stents 100, 100a and 100b can be coated with a polymeric material. For example, the stent wire of the stent 30 can be partially or entirely covered with a bioactive material, the bioactive material being disposed uniformly with the polymeric material. In addition, the polymeric coating can extend over or through the interstitial spaces between the stent wires so as to provide a hollow tube lining or covering on the inner or outer surface of the stent, thereby providing a stent-graft device. The polymeric material can be selected from the group consisting of polyesters, polypropylenes, polyethylenes, polyurethanes, polynaphthalenes, polytetrafluoroethylene, expanded polytetrafluoroethylene, silicones and combinations thereof. The covering can be in the form of a tubular structure. The silicone covering can be suitably formed by dip coating the stent. The present application is not limited to forming the silicone film by dip coating, but other techniques such as spray coating, etc. can be suitably used. After the silicone coating or film is applied to the stent, the silicone can be cured. The curing can be a low temperature cure, for example, from about room temperature to about 90°C for a short period of time, for example, from about 10 minutes or more to about 16 hours. The cured silicone covering can also be sterilized by electron beam radiation, gamma radiation ethylene oxide treatment, etc. The cured silicone can also be treated with argon plasma. Among other things, the argon plasma treatment of the cured silicone surface modifies the cured silicone, thereby reducing the surface tackiness. However, the present application is not limited to stent-graft devices having a polymeric coating. The graft portion can be suitably formed from polymeric films, polymeric tapes, polymeric tubes, polymeric sheets and textile materials. The textile materials can be woven, knitted, braided and / or fiber wound to provide a suitable graft.

[0082] Various biocompatible polymeric materials can be used as the textile material to form the textile structure, including polyethylene terephthalate (PET), naphthalene dicarboxylate derivatives such as polyethylene naphthalate, polybutylene naphthalate, polypropylene naphthalate, polypropylene naphthalate, ePTFE, natural silk, polyethylene and polypropylene, etc. In addition, the textile material and the stent material can be co-formed (e.g., co-braided) to form the stent-graft device.

[0083] Various self-expanding stents can be employed in the present application. Self-expanding stents can include stents having a spring-like action that causes the stent to radially expand, or stents that expand due to the memory properties of the stent material for a particular configuration at a certain temperature. Nitinol is one material that performs well in both the spring-like mode and the temperature-based memory mode. Other materials such as stainless steel, platinum, gold, titanium, and other biocompatible metals can be considered, as well as polymeric stents including biodegradable and bioabsorbable stents. The configuration of the stent can also be selected from a large number of geometries. For example, wire stents can be secured in a continuous helical pattern with or without wave or zig-zag in the wire to form a radially deformable stent. Individual rings or circular members can be linked together such as by struts of the rings, stitching, welding, or interlocking to form a tubular stent. Tubular stents for use in the present application also include those formed by etching or cutting a pattern from a tube. Such stents are commonly referred to as slotted stents. In addition, stents can be formed by etching a pattern into a material or mold and depositing the stent material such as by chemical vapor deposition into the pattern.

[0084] The inner sheath 50 and / or the outer sheath 60 can be constructed of any suitable biocompatible material such as, but not limited to, polymeric polymers and materials, including fillers, e.g., metals, carbon fibers, glass fibers, or ceramics, and combinations thereof. Usefully, but not limitingly, polymeric materials include polyethylene, polypropylene, polyvinyl chloride, polytetrafluoroethylene, fluorinated ethylene propylene copolymer, polyvinyl acetate, polystyrene, polyethylene terephthalate, naphthalene dicarboxylate derivatives such as polyethylene naphthalate, polybutylene naphthalate, polypropylene naphthalate, and polypropylene naphthalate, polyurethane, polyurea, silicone rubber, polyamide, polycarbonate, polyaldehyde, natural rubber, polyester copolymer, styrene-butadiene copolymer, polyether, fully or partially halogenated polyether, polyamide-polyether polyester, and copolymers and combinations thereof.

[0085] In addition, the inner sheath 50 and / or the outer sheath 60 can be reinforced to provide greater strength while minimizing the overall tube profile. For example, the inner sheath 50 and / or the outer sheath 60 can have reinforcing material, e.g., polymeric, metallic, or ceramic strands or tapes, wrapped around or otherwise disposed on or within the tube. The reinforcing strands or tapes can be braided, woven, wrapped, and generally form a reinforcing member for the tube.

[0086] While various embodiments of the disclosed technology have been described above, it should be understood that these embodiments are presented by way of example only and not as limitation. Similarly, various figures may depict exemplary schematics or other constructions of the disclosed technology, done to aid in understanding the features and functions that may be included in the disclosed technology. The disclosed technology is not limited to the illustrated exemplary schematics or constructions, but various alternative illustrations and constructions may be used to implement the desired features. Indeed, it will be apparent to those skilled in the art how alternative functions, logical or physical parts and constructions can be implemented to carry out the desired features of the technology disclosed herein.

[0087] While the disclosed technology has been described above with reference to various exemplary embodiments and implementations, it should be understood that the various features, aspects, and functions described in one or more individual embodiments are not limited to their applicability to the particular embodiment described therein, but can be applied individually or in various combinations to one or more other embodiments of the disclosed technology, whether or not such embodiment is described, and whether such feature is presented as part of such embodiment. Therefore, the breadth and scope of the technology disclosed herein should not be limited to any of the exemplary embodiments described above.

[0088] The terms and phrases used herein, and their variations thereof, should be interpreted as open-ended rather than restrictive, unless otherwise expressly stated. As examples of the foregoing: the term “comprising” should be interpreted as “including, but not limited to”, etc.; the term “example” is used to provide exemplary instances of the items discussed, not an exhaustive or restrictive enumeration; the term “a” should be interpreted as “at least one,” “one or more,” etc.; adjectives such as “conventional,” “traditional,” “normal,” “standard,” “known,” etc., and terms with similar meanings, should not be interpreted as limiting the items to a given time period or restricting items available within a given time period, but should be interpreted as including conventional, traditional, normal, or standard techniques available or known at any time now or in the future. Similarly, when this document refers to techniques obvious or known to a person skilled in the art, such techniques encompass those obvious or known to a person skilled in the art at any time now or in the future.

[0089] In some cases, the presence of broadening words and phrases such as “one or more,” “at least,” “but not limited to,” or other similar phrases should not be interpreted as an intention to or requirement of a narrower situation in the absence of such a broadening phrase.

Claims

1. A stent comprising: a wire, which is woven into a tubular fence to form a stent body, the stent body comprising: a plurality of tubular units connected together, the plurality of tubular units being arranged around a longitudinal central axis of the stent body; and a plurality of connection sites configured to connect adjacent ones of the plurality of tubular units and arranged along a plurality of circumferences with respect to the longitudinal central axis of the stent body, wherein the plurality of circumferences comprises a first circumference having a first radius and a second circumference having a second radius, and the first radius is different in length from the second radius, the plurality of connection sites comprises first connection sites arranged along the first circumference and second connection sites arranged along the second circumference, each of the first connection sites is located at the first radius and each of the second connection sites is located at the second radius, and a difference between the first radius and the second radius forms a step between each of the first connection sites and each of the second connection sites.

2. The stent of claim 1, wherein A height of the step is at least equal to a radius of the wire of the stent.

3. The stent of claim 1, wherein The first circumference and the second circumference are concentric circles.

4. The stent of claim 1, wherein The first circumference is spaced apart from the second circumference along the longitudinal central axis of the stent.

5. The stent defined in Claim 1, wherein, The plurality of circumferences further comprises a third circumference having a third radius different in length from the first radius and the second radius, the plurality of connection sites further comprises third connection sites arranged along the third circumference, and each of the first connection sites is located at the first radius, each of the second connection sites is located at the second radius, and each of the third connection sites is located at the third radius.

6. The stent defined in Claim 5, wherein, A difference between the first radius and the second radius forms a first step between each of the first connection sites and each of the second connection sites, and a difference between the second radius and the third radius forms a second step between each of the second connection sites and each of the third connection sites, and a height of each of the first step and the second step is not less than a radius of the wire of the stent.

7. The stent defined in Claim 5, wherein, The first circumference, the second circumference, and the third circumference are concentric circles.

8. The stent defined in Claim 5, wherein, The plurality of circumferences further comprises a fourth circumference having a fourth radius different in length from the first radius, the second radius, and the third radius, the plurality of connection sites further comprises fourth connection sites arranged along the fourth circumference, and each of the fourth connection sites is located at the fourth radius.

9. The stent defined in Claim 8, wherein, A difference between the first radius and the second radius forms a first step between each of the first connection sites and each of the second connection sites, a difference between the second radius and the third radius forms a second step between each of the second connection sites and each of the third connection sites, a difference between the third radius and the fourth radius forms a third step between each of the third connection sites and each of the fourth connection sites, and a height of each of the first step, the second step, and the third step is not less than a radius of the wire of the stent.

10. The stent defined in Claim 8, wherein, The first circumference, the second circumference, the third circumference, and the fourth circumference are concentric circles.

11. The stent defined in Claim 1, wherein, The plurality of connection sites are each formed by hooking a first bend of the wire with a second bend of the wire.

12. The stent defined in Claim 11, wherein, The first bend is a first convex portion in which a side of the wire extending in a circumferential direction is bent rearward toward a longitudinal center axis direction, and the second bend is a second convex portion in which a side of the wire extending in the circumferential direction is bent rearward toward an opposite side of the longitudinal center axis direction.

13. A stent comprising: a wire woven into a tubular fence; a first entanglement connection formed by hooking a first bend of the wire with a second bend of the wire; and a second entanglement connection formed by hooking a third bend of the wire with a fourth bend of the wire, wherein the first bend is adjacent to the third bend in a circumferential direction, and the second bend is adjacent to the fourth bend in the circumferential direction, a first radial distance between the first entanglement connection and a longitudinal center axis of the stent is different from a second radial distance between the second entanglement connection and the longitudinal center axis of the stent, and a difference between the first radial distance and the second radial distance is a height of a step formed between the first entanglement connection and the second entanglement connection.

14. The stent defined in Claim 13, wherein, The first bend is a first convex portion in which a side of the wire extending in a circumferential direction is bent rearward toward a longitudinal center axis direction, and the second bend is a second convex portion in which a side of the wire extending in the circumferential direction is bent rearward toward an opposite side of the longitudinal center axis direction.

15. The stent defined in Claim 14, wherein, The height of the step is at least equal to a radius of the wire.

16. The stent defined in Claim 13, wherein, The first entanglement connection is disposed along a first circumference, the second entanglement connection is disposed along a second circumference, and The first circumference and the second circumference are concentric circles.

17. The stent defined in Claim 13, wherein, The first entanglement connection is disposed along a first circumference, the second entanglement connection is disposed along a second circumference, and The first circumference is adjacent to the second circumference along a longitudinal center axis of the stent.

18. The stent defined in Claim 13, wherein, The stent further comprises a third entanglement connection, and a third radial distance between the third entanglement connection and the longitudinal center axis of the stent is different from the first radial distance and the second radial distance.

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