Anti-migration stent

Abstract

A stent includes an expandable tubular body formed from one or more interwoven threads and including a plurality of anti-migration features each having a first end secured to the tubular body and a second end extending radially outward from an outer surface of the tubular body. The anti-migration feature may be formed from a closed loop of one or more of the interlaced threads extending from the outer surface of the tubular body. The closed loop may be formed at the first end, the second end, and / or an intermediate region along the tubular body. In some cases, the base of the loop may be an intersection of the lines forming the closed loop. The wires may be welded at the intersections.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of and priority to U.S. Provisional Patent Application Serial No. 63 / 393,516, filed on July 29, 2022, the disclosure of which is incorporated herein by reference. Technical Field

[0003] The present invention relates to medical devices, and more particularly to implantable stents having anti-migration characteristics, and methods of using such medical devices. Background Art

[0004] Various medical devices for medical use have been developed, including, for example, medical devices for treating body cavities. One type of intraluminal prosthesis for repairing and / or treating diseases in various body cavities is a stent. A stent is a generally longitudinal tubular device formed of a biocompatible material that can be used to open and support various cavities in the body. The stent can be used in various cavities in the body, such as in the vascular system, bile duct, urogenital tract, gastrointestinal tract, esophagus, trachea / bronchus and bile duct, and in various other cavities in the body. Each of the known medical devices and methods has certain advantages and disadvantages. There is a need to provide alternative medical devices and alternative methods for making and using medical devices. Summary of the invention

[0005] The present invention provides designs, materials, manufacturing methods and use alternatives for medical devices. An example stent includes a tubular body formed of interwoven wires, the tubular body having a first open end, an opposite second open end and a central longitudinal axis extending therebetween, the tubular body being movable between a radially compressed state and a radially expanded state; and a plurality of anti-migration features, each of the plurality of anti-migration features having a first end positioned at an outer surface of the tubular body and a second end extending radially outward from the outer surface of the tubular body, wherein each of the plurality of anti-migration features is defined by a closed loop of one or more of the interwoven wires, wherein the base of the closed loop is located at the outer surface of the tubular body.

[0006] Alternatively or additionally to the above embodiments, the base of the closed loop includes intersections of the one or more interwoven threads forming the closed loop.

[0007] Alternatively or additionally to any of the above embodiments, one or more interwoven wires are welded at the intersection points.

[0008] Alternatively or additionally to any of the above embodiments, any tensile or compressive forces applied to any of the plurality of anti-migration features do not reduce the outer diameter of the tubular body or axially lengthen or shorten the tubular body.

[0009] Alternatively or additionally to any of the above embodiments, a first portion of the plurality of anti-migration features is coupled to the tubular body adjacent the first open end and extends toward the second open end at an acute angle relative to an outer surface of the tubular body.

[0010] Alternatively or additionally to any of the above embodiments, a second portion of the plurality of anti-migration features is coupled to the tubular body adjacent the second open end and extends at an acute angle toward the first open end.

[0011] Alternatively or additionally to any of the above embodiments, a first portion of the plurality of anti-migration features is connected to the middle region of the tubular body and extends at an acute angle toward the first open end, and a second portion of the plurality of anti-migration features is connected to the middle region of the tubular body and extends at an acute angle toward the second open end.

[0012] Alternatively or additionally to any of the above embodiments, the base of each anti-migration feature of the first portion and the base of each anti-migration feature of the second portion are circumferentially spaced apart at a single longitudinal location along the tubular body.

[0013] Alternatively or additionally to any of the above embodiments, a closed loop defining a plurality of anti-migration features is located at the first open end and extends radially outward from the tubular body.

[0014] Alternatively or additionally to any of the above embodiments, the stent further comprises a plurality of elongated closed loops at the first open end that are substantially parallel to the central longitudinal axis.

[0015] Alternatively or additionally to any of the above embodiments, a plurality of elongated closed loops are interposed between adjacent ones of the closed loops defining the plurality of anti-migration features.

[0016] Alternatively or additionally to any of the above embodiments, each closed loop is formed from a plurality of interwoven wires, wherein ends of the plurality of interwoven wires are welded around a perimeter of the closed loop.

[0017] Alternatively or additionally to any of the above embodiments, each closed loop is formed by segments of four of the interwoven wires that together define the perimeter of the closed loop.

[0018] Alternatively or additionally to any of the above embodiments, the base comprises an intersection of first and second threads of interwoven threads forming a closed loop.

[0019] Alternatively or additionally to any of the above embodiments, the first and second wires are welded together at the intersection.

[0020] Another example stent includes a tubular body formed by interwoven wires, the tubular body having a first open end, an opposing second open end, and a central longitudinal axis extending therebetween, the tubular body being movable between a radially compressed state and a radially expanded state; and a plurality of anti-migration features, each of the plurality of anti-migration features having a first end welded to one or more intersections of one or more interwoven wires forming the tubular body, and a second end extending radially outward from an outer surface of the tubular body.

[0021] Alternatively or additionally to any of the above embodiments, each of the plurality of anti-migration features is at least partially formed from a wire of the interwoven wires forming the tubular body.

[0022] Alternatively or additionally to any of the above embodiments, each of the plurality of anti-migration features is formed from a plurality of wires of the interwoven wires arranged in a closed loop, wherein ends of the plurality of wires are welded around a perimeter of the closed loop.

[0023] Another example stent includes a radially expandable tubular body formed by interwoven wires, the tubular body having a first open end, an opposite second open end and a central longitudinal axis extending therebetween, the tubular body being movable between a radially compressed state and a radially expanded state; and a plurality of anti-migration features located at the first open end, each of the plurality of anti-migration features having a first end positioned at an outer surface of the tubular body and a second end extending radially outward from the outer surface of the tubular body, wherein each of the plurality of anti-migration features is formed by a plurality of wires of the interwoven wires arranged in a closed loop, wherein the ends of the plurality of wires are arranged around the periphery of the closed loop.

[0024] Alternatively or additionally to the above embodiments, the ends of the plurality of wires are welded around the perimeter of the closed loop.

[0025] The above summary of some embodiments, aspects and / or examples is not intended to describe every embodiment or every implementation of the present invention. The following figures and detailed description more particularly exemplify these embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention may be more fully understood by considering the following detailed description of various embodiments in conjunction with the accompanying drawings, in which:

[0027] Figure 1 is a side view of an example bracket;

[0028] Figure 1A yes Figure 1 illustrative views of end regions of a stent;

[0029] Figure 1B and Figure 1C yes Figure 1 an alternative end region of the stent;

[0030] Figures 2 to 8 is a side view of an additional example bracket;

[0031] Fig.9A is a partial side cross-sectional view of another example stent;

[0032] Fig. 9B yes Fig.9A An end view of the bracket;

[0033] Fig.10 is a side view of another example bracket;

[0034] Fig.11A is a side cross-sectional view of another example stent deployed between two body lumens; and

[0035] Fig. 11B is extended through the tissue Fig.11A A stereo end view of the stent.

[0036] Although the various aspects of the present invention are suitable for various modifications and alternative forms, the specific details thereof have been shown in the drawings by way of example and will be described in more detail. However, it should be understood that it is not intended to limit the various aspects of the present invention to the specific embodiments described. On the contrary, it is intended to cover all modifications, equivalents and substitutes that fall within the spirit and scope of the present invention. DETAILED DESCRIPTION

[0037] For the following defined terms, these definitions shall apply unless a different definition is given in the claims or elsewhere in this specification.

[0038] All numerical values ​​are assumed to be modified by the term "about" herein, whether or not explicitly indicated. In the context of numerical values, the term "about" generally refers to a numerical range that is considered by those skilled in the art to be equivalent to the quoted value (e.g., having the same function or result). In many cases, the term "about" may include numbers rounded to the nearest significant figure. Unless otherwise specified, the term "about" (e.g., in contexts other than numerical values) may be assumed to have its ordinary and customary definition, as understood and consistent with the context of this specification.

[0039] References to numerical ranges by endpoints include all values ​​within that range, including the endpoints (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). Although some suitable sizes, ranges, and / or values ​​are disclosed for various components, features, and / or specifications, those skilled in the art to which the present invention relates will appreciate that the desired sizes, ranges, and / or values ​​can be derived from those explicitly disclosed.

[0040] As used in this specification and the appended claims, the singular forms "a", "an" and "the" include plural referents unless the content clearly indicates otherwise. As used in this specification and the appended claims, the term "or" is generally used in a sense that includes "and / or" unless the content clearly indicates otherwise. It should be noted that, for ease of understanding, certain features of the present invention may be described in the singular, even if those features may be plural or repeated in the disclosed embodiments. Each instance of a feature may include and / or contain a singular disclosure unless expressly indicated to the contrary. For simplicity and clarity, not all elements of the present invention must be shown in each figure or discussed in detail below. However, it will be understood that, unless expressly indicated to the contrary, the following discussion may also apply to any and / or all of more than one component. Additionally, for clarity, all instances of some elements or features may not be shown in each figure.

[0041] Relative terms, such as "proximal", "distal", "advance", "extraction", variations thereof, and the like, may generally be considered with respect to the positioning, orientation, and / or operation of various elements relative to a user / operator / manipulator of the device, with "proximal" and "extraction" meaning or referring to closer to or toward the user and "distal" and "advance" meaning or referring to farther from or away from the user. In some instances, the terms "proximal" and "distal" may be arbitrarily assigned to facilitate understanding of the present disclosure, and such instances will be apparent to a skilled person. Other related terms, such as "upstream", "downstream", "inflow", and "outflow" refer to the direction of liquid flow within a cavity, such as a body cavity, a blood vessel, or a device.

[0042] The term "range" may be understood to mean the maximum measure of the dimensions described and identified, unless the range and dimensions in question are preceded by "minimum" or identified as "minimum", which may be understood to mean the minimum measure of the dimensions described and identified. For example, "external range" may be understood to mean the maximum external dimension, "radial range" may be understood to mean the maximum radial dimension, "longitudinal range" may be understood to mean the maximum longitudinal dimension, etc. Each instance of "range" may be different (e.g., axial, longitudinal, lateral, radial, circumferential, etc.), and will become apparent to the skilled person based on the context of individual use. Generally, "range" may be considered to be the maximum possible dimension measured according to the intended use, while "minimum range" may be considered to be the minimum possible dimension measured according to the intended use. In some instances, "range" may generally be measured orthogonally in a plane and / or cross section, but may also be measured differently, such as, but not limited to, angularly, radially, circumferentially (e.g., along an arc), etc., as will be apparent from the particular context. Additionally, the term "substantially" when used to refer to two dimensions being "substantially the same" generally refers to a difference of less than or equal to 5%.

[0043] The terms "integral" and "unitary" shall generally refer to an element or elements that are made or composed of a single structure or base unit / element. Integral and / or unitary elements shall exclude structures and / or features that result from assembling or otherwise combining together multiple discrete elements.

[0044] It should be noted that references in the specification to "one embodiment", "some embodiments", "other embodiments", etc. indicate that the described embodiments may include a particular feature, structure, or characteristic, but each embodiment may not necessarily include the particular feature, structure, or characteristic. In addition, such phrases do not necessarily refer to the same embodiment. In addition, when a particular feature, structure, or characteristic is described in conjunction with one embodiment, whether or not explicitly described, it is within the knowledge of a person skilled in the art to implement such particular feature, structure, or characteristic in conjunction with other embodiments, unless explicitly stated to the contrary. That is, even if not explicitly shown in a particular combination, the various individual elements described below are still considered to be combinable or arranged with each other to form other additional embodiments or to supplement and / or enrich the described embodiments, as will be understood by a person of ordinary skill in the art.

[0045] For the sake of clarity, various descriptions and / or claimed features can be named and / or distinguished using certain identifying digital nomenclature (e.g., first, second, third, fourth, etc.) throughout the specification and / or claims. It is to be understood that the digital nomenclature is not intended to be limiting and is merely exemplary. In certain embodiments, for the sake of brevity and clarity, the digital nomenclature previously used can be changed and deviated from. That is, the feature identified as a "first" element can be referred to as a "second" element later, a "third" element, etc., or can be completely omitted, and / or different features can be referred to as a "first" element. The meaning and / or name in each instance will be apparent to the technician.

[0046] The following description should be read with reference to the accompanying drawings, which are not necessarily drawn to scale, in which similar elements in different figures have the same numbering. The detailed description and the accompanying drawings are intended to illustrate rather than limit the present invention. Those skilled in the art will recognize that the various elements described and / or shown may be arranged in various combinations and configurations without departing from the scope of the present invention. The detailed description and the accompanying drawings illustrate example embodiments of the present invention. However, for the purpose of clarity and ease of understanding, although each feature and / or element may not be shown in each figure, the features and / or elements may also be understood to be present unless otherwise stated.

[0047] Self-expanding stents, such as fully covered stents, may be subject to stent migration. Current self-expanding stents, such as those used in endoscopic applications, may have features that promote resistance to migration, such as flared or tapered regions. These mechanical changes have achieved varying degrees of success in reducing stent migration.

[0048] Figure 1 An expandable stent 100 having a plurality of anti-migration features 150 is shown. The stent 100 includes an expandable tubular body 120 having a first open end 122 and an opposing second open end 124, and a central longitudinal axis XX extending therebetween. The walls of the expandable stent 100 can define a cavity extending through the stent 100 along the central longitudinal axis XX from the first open end 122 to the second open end 124. In some cases, for example, the stent 100 can have a length of 30 mm to 200 mm and an outer diameter of about 4 mm to about 28 mm. These dimensions are merely exemplary. Other lengths and / or diameters are also contemplated. As Figure 1 As shown, the tubular body 120 can be expanded from a radially compressed delivery state to a radially expanded deployment state. As known in the art, the stent 100 can be self-expanded from a compressed delivery state to an expanded deployment state, or can be expanded from a compressed delivery state to an expanded deployment state by a balloon or other expansion device. The tubular body 120 can be defined by a stent wall having an inner surface and an outer surface.

[0049] The stent 100 described herein may have a substantially constant diameter from the first open end 122 to the second open end 124, such as Figure 1 Alternatively, the stent 100 may have one or both end regions with a diameter greater than the middle region, such as Figure 2 As shown. Such a stent may be considered to have a first flared end region and / or a second flared end region as desired.

[0050] The stent 100 may be formed from one or more interwoven threads or a plurality of interwoven threads 140 that form a tubular body 120 of the stent 100. The interwoven threads 140 may be knitted, braided, wrapped, looped, or otherwise interwoven along the length of the tubular body 120. Figure 1 As shown, the tubular body 120 may include a series of closed loops at one or both of the opposing first and second open ends 122, 124. As used herein, the term "closed loop" means a loop having a closed perimeter, wherein the entire perimeter of the loop is defined by one or more of the wires 140. In some embodiments, one or both of the open ends 122, 124 may include an elongated closed loop 160. Figure 1 As shown, the closed loop at the first open end 122 is an elongated closed loop 160, and the closed loop 161 at the second open end 124 is similar in size to the unit defined by the woven or braided wires 140 along the tubular body 120. In some cases, the ends of each of the interwoven wires 140 may be located at the first open end 122, so that the ends of the interwoven wires 140 form a closed loop 160 at the first open end 122, and the curved portion along the middle region of the interwoven wires 140 may form a closed loop 161 at the second open end 124. In other embodiments, if desired, the ends of some of the interwoven wires 140 may be located at the second open end 124, while the ends of other interwoven wires 140 may be located at the first open end 122. In other embodiments, the tubular body 120 may take the form of a mesh that is laser cut from a tube or laser cut from a sheet of material that is welded to form a tube.

[0051] The stent 100 may include a plurality of anti-migration features 150 extending radially outward from the outer surface of the tubular body 120. In some embodiments, one or more of the elongated closed loops 160 formed at one or both of the first open end 122 and the second open end 124 may define the anti-migration features 150. The anti-migration features 150 may be formed by one or more of the interwoven wires 140 that form the tubular body 120. In this embodiment, the anti-migration features 150 may be formed with the same wires that are interwoven to form the body of the stent 100. In other embodiments, the anti-migration features 150 may be formed separately and then secured to the tubular body 120 at, for example, the wire intersections 126. In this case, the anti-migration features 150 may be attached to the tubular body 120 by welding or adhesively bonding the base of the anti-migration features to, for example, the interwoven wires that form the body of the stent 100.

[0052] like Figure 1A , Figure 1B and Figure 1CAs shown, the elongated closed loop 160 at the first open end 122 is bent outward to form the anti-migration feature 150. Each of the anti-migration features 150 or closed loops 160 can have a first end 152 located at the wall of the tubular body 120 or otherwise coupled to the tubular body 120 and a second end 154 extending radially outward from the outer surface of the tubular body 120 to the apex of the anti-migration loop 160. As described herein, the extension direction of the anti-migration loop 160 is a direction from the first base end 152 located at the tubular body 120 to the second free end 154 of the anti-migration loop 160. The anti-migration feature 150 (e.g., the anti-migration loop 160) can have a length measured from the first end 152 to the second end 154. In some embodiments, at least some of the anti-migration features 150 can have a length of at least one-third of the outer diameter of the tubular body 120 measured at the widest point of the tubular body 120. In other embodiments, the length of the anti-migration feature 150 may be at least one-half of the outer diameter of the tubular body 120. In some cases, the first end 152 or base of each anti-migration feature 150 (e.g., anti-migration ring 160) may be fixed or fixedly attached to the tubular body 120 such that any pulling or compressive force applied to the anti-migration feature 150 (e.g., anti-migration ring 160) in any direction does not cause the size of the anti-migration feature 150 (e.g., anti-migration ring 160) to increase or decrease, and does not reduce or expand the outer diameter of the tubular body 120, or lengthen or shorten the tubular body 120. Thus, in some cases, the size of each anti-migration feature 150 may be fixed. In some cases, when the wires 51 / 52 extend from the tubular body 120 to begin to form the closed loop 160, the base or first end 152 of the closed loop 160 is formed by the first wire 51 crossing over / under the second wire 52. In other words, in embodiments where the anti-migration feature 150 is formed from a plurality of wires 140 forming an interwoven tubular body 120, the first end 152 can be defined by an intersection 126 where two wires 140 extend from the interwoven tubular body 120 and cross each other when the wires 140 form the anti-migration feature 150. Thus, the intersection 126 of the first and second wires 51 / 52 can define a portion of the closed perimeter of the closed loop 160. In some cases, the first end 152 or base of each anti-migration closed loop 160 of the plurality of anti-migration loops 160 can be arranged at a single circumferential row of intersections 126 located at the first end 122 of the stent 100. In other words, the intersection of the plurality of anti-migration loops 160 located at one end of the stent can be located at a single longitudinal position circumferentially around the tubular body 120.

[0053] exist Figure 1A It is shown in Figure 1 FIG. 1 is an enlarged view of the end region of the stent 10. Figure 1AAs shown, each closed loop 160 forming the anti-migration feature 150 may be formed by a plurality of wires 140 extending from the interwoven tubular body 120 and fixed to each other (e.g., welded). For example, a first wire 51 extending along the interwoven tubular body 120 in a first spiral direction may extend from the interwoven tubular body 120 and bend to form an apex 64 of the loop 160 at a free end 154 of the loop 160. A second wire 52 extending along the interwoven tubular body 120 in a second spiral direction opposite to the first spiral direction may cross over the first wire 52 at a base end 152 of the loop 160 and may have an end joined to an end of the first wire 51 at a first fixed position 61 along the periphery of the loop 160. A third wire 53 may extend along the interwoven tubular body 120 in the first spiral direction parallel to the first wire 51 and may have an end joined to an end of the first wire 51 and / or the second wire 52 at a first fixed position 61. The fourth wire 54 can extend along the interwoven tubular body 120 in a second spiral direction parallel to the second wire 52, and can have an end joined to the first wire 51 at a second fixing location 62. In some cases, the first and second fixing locations can be welding locations. For example, the ends of the first, second, and third wires can be welded together at the first fixing location 61, and the end of the fourth wire 54 can be welded to the first wire 51 at the second fixing location 62. For example, the first and second fixing locations can be located on opposite sides of the ring 160. Therefore, the periphery of each ring 160 can be formed by a portion of the four individual wires 140 of the tubular body 120. Therefore, in some cases, the stent 100 can include four times the number of wires forming the tubular body 120 as the ring 160 at the first end of the stent 100. Figure 1A In an embodiment of the present invention, the first wire 51 may cross over the second wire 52, but is not fixed to the second wire 52 at the intersection 126 of the base 152 of the loop 160. In another embodiment, as Figure 1B As shown, the first wire 51 may cross over the second wire 52 at the intersection 126 of the base 152 of the loop 160 and be welded together at the intersection 126. When the wires 51 / 52 are welded together at the intersection 126, the deflection of the anti-migration feature 150 may not reduce or increase the diameter or length of the tubular body 120 and therefore will not act as a retrieval element.

[0054] The second end 154 of the closed loop 160 may be a free end that forms the apex 64 of the closed loop 160. The second ends 154 of at least some of the anti-migration features 150 may extend radially outward beyond the outermost extent of the outer surface of the tubular body 120. In some cases, the first end 152 of the anti-migration feature 150 may include a single attachment point to the tubular body 120, while in other cases, the first end 152 of the anti-migration feature 150 may include multiple attachment points to the tubular body 120. For example, the anti-migration feature 150 may be defined by a wire or multiple wires 140 that exit and subsequently re-enter the tubular body 120 at different spaced-apart locations, such that the first end 152 of the anti-migration feature 150 is defined by multiple wire intersections 126 and / or multiple weld locations. In some embodiments, as shown in FIG. Figure 1A and Figure 1B As shown, the first end 152 of the anti-migration feature 150 coupled to the tubular body 120 can be defined at a single wire intersection 126 where two wires (e.g., the first wire 51 and the second wire 52) cross each other as they extend from the tubular body 120. In some cases, such as Figure 1B As shown, weld 153 can secure first end 152 to prevent anti-migration feature 150 from expanding at intersection 126. Regardless of how many wire intersections 126 are involved in defining anti-migration feature 150, wire intersections 126 can be welded so that any tensile or compressive forces applied to anti-migration feature 150 do not change the diameter of tubular body 120 or lengthen / shorten tubular body 120. In such a case, anti-migration feature 150 does not act as a retrieval element that compresses and / or lengthens stent 100 for removal.

[0055] exist Figure 1CIn another embodiment shown, the first end 122 of the stent 100 may include a plurality of large closed loops 160 forming an anti-migration feature 150, wherein a plurality of smaller closed loops 165 are interposed between adjacent closed loops in the larger closed loops 160. Each closed loop 160 and each smaller closed loop 165 forming the anti-migration feature 150 may be formed by a plurality of wires 140 extending from the interwoven tubular body 120 and fixed to each other. For example, a first wire 51 extending in a first spiral direction along the interwoven tubular body 120 may extend from the interwoven tubular body 120 and bend to form an apex 64 of the large closed loop 160 at a free end 154 of the closed loop 160. A second wire 52 extending along the interwoven tubular body 120 in a second spiral direction opposite to the first spiral direction may cross over the first wire 52 at a base end 152 of the loop 160, and may have an end joined to an end of the first wire 51 along the periphery of the loop 160 at a first fixed position 61. A third wire 53, which may extend along the interwoven tubular body 120 in a first helical direction parallel to the first wire 51, may bend around to form the apex of a smaller closed loop 165. A fourth wire 54, which may extend along the interwoven tubular body 120 in a second helical direction parallel to the second wire 52, may have an end joined to the third wire 51 at a second fixed position 63. In some cases, larger loops 160 alternate with smaller loops 165 around the circumference of the end 122 of the tubular body 120 of the stent 100. In some cases, the smaller loops 165 may be juxtaposed with the larger closed loops 160, but the perimeter of the smaller closed loops 165 may not be fixed to the perimeter of the larger closed loops 160. In other words, the perimeter of the larger closed loop 160 may not be fixed (e.g., welded) to the perimeter of the smaller loop 165, so that the larger loop 160 may be free to deflect relative to the smaller loop 165. The larger closed loop 160 may bend radially outward relative to the smaller loop 165. For example, the smaller closed loop 165 may extend longitudinally substantially parallel to the wall of the tubular body 120 , while the larger loop 160 may extend radially outward at an oblique angle (ie, acute or obtuse) or perpendicular to the smaller loop 165 .

[0056] Anti-migration characteristics 150 (in Figures 1A to 1C , some examples of which are shown in FIG. 1 ), can extend outwardly from the outer surface of tubular body 120 at an angle θ (such as an oblique angle or a perpendicular angle) relative to the central longitudinal axis and / or the outer surface of tubular body 120. In some cases, the angle can be an obtuse angle, such as Figure 1120 , wherein the anti-migration feature 150 extends toward the first open end 122. In other cases, the angle may be an acute angle, if desired, wherein the anti-migration feature 150 bends back toward the second open end 124. In other cases, the angle may be a vertical angle. In some cases, the angle θ may be between about 10 degrees and about 160 degrees, between about 100 degrees and about 160 degrees, between about 100 degrees and about 140 degrees, between about 90 degrees and about 120 degrees, between about 20 degrees and about 90 degrees, between about 30 degrees and about 80 degrees, between about 20 degrees and about 45 degrees, etc. The second ends 154 of at least some of the anti-migration features 150 extend radially outward beyond the outermost extent of the surface of the tubular body 120. The plurality of anti-migration features 150 may be biased in an extended angled position relative to the tubular body 120 when unconstrained and / or when the stent is deployed to an expanded configuration.

[0057] In some embodiments, the stent 100 may include a covering 70 (see Figure 1 ), which is disposed over at least a portion of the tubular body 120 of the stent 100. For example, the covering 70 may completely cover the entire length of the tubular body 120 of the stent 100, thereby forming a fully covered stent, wherein all gaps or closed cells defined by an interlaced pattern (e.g., a braided pattern) of the tubular body 120 are covered with the covering 70 to prevent tissue ingrowth and / or fluid leakage into the lumen of the tubular body 120. In other examples, the covering 70 may only cover a portion of the length of the tubular body 20 of the stent 100, thereby forming a partially covered stent, wherein a portion of the gaps or closed cells defined by an interlaced pattern (e.g., a braided pattern) remain uncovered, thereby allowing tissue ingrowth. In some cases, the anti-migration feature 150 may be covered by the covering 70, and thus the entire stent 100, including the entire tubular body 120 and the anti-migration feature 150 and the closed loop 60, may be covered by the covering 70. In some cases, the stent 100 can be immersed in a solution of silicone or other polymers to form the covering 70, or the stent 100 can be sprayed with silicone or other polymers to form the covering 70. In other cases, a polymer sheet or tube can be placed around and / or inside the tubular body 120 to form the covering 70. The covering 70 can be disposed on the outer or inner surface of the tubular body 120, or on both the inner and outer surfaces of the tubular body 120, thereby embedding the tubular body 120 of the stent 100 in a polymer material. The coating or covering can be a polymer covering, such as polytetrafluoroethylene (PTFE) or a silicone covering, however, other coverings, particularly elastomeric polymers, can also be used. Non-limiting examples of useful polymer materials include polyester, polypropylene, polyethylene, polyurethane, polynaphthalene, polytetrafluoroethylene, expanded polytetrafluoroethylene, silicone, and combinations and copolymers thereof.

[0058] In another embodiment, stent 200, similar to stent 100, can have a plurality of anti-migration features 250 formed by closed loops 260 extending radially outward from the outer surface of tubular body 220 at an angle of approximately 90 degrees, such as Figure 2 As shown. The anti-migration feature 250 can be configured as a closed loop formed by one or more or more wires forming the interwoven tubular body 200, similar to the anti-migration feature 150 described above. The plurality of anti-migration features 250 can be biased in an extended angled position relative to the tubular body 220 when unconstrained and / or when the stent is deployed to an expanded configuration. The tubular body 220 may include a first outwardly flared region 227 at the first open end 222 and / or a second outwardly flared region 229 at the second open end 224. The first and / or second outwardly flared regions 227, 229 may have an outer diameter that is larger than the outer diameter of the remainder of the tubular body 220. The plurality of anti-migration features 250 may extend from the first and / or second outwardly flared regions 227, 229. Although in Figure 2 Only two anti-migration features 250 (e.g., closed loops) are visible in the side view shown, but it is readily understood that additional anti-migration features 250 (e.g., closed loops) may extend around the circumference of the first open end 222, similar to Figure 1 In some cases, the first end 252 or base of each anti-migration closed loop 260 in the plurality of anti-migration loops 260 can be arranged at a single circumferential row of intersections 220 of lines forming the tubular body 220 located at the first end 222 of the stent 200. In other words, the intersection of the plurality of anti-migration loops 260 located at one end of the stent can be located at a single longitudinal position circumferentially around the tubular body 220.

[0059] Figure 3Another embodiment of a stent 300 is shown in which a plurality of anti-migration features 350 formed as closed loops 360 alternate with elongated closed loops 368 extending parallel to the longitudinal axis of the tubular body 320, wherein the anti-migration features 350 are formed at the first open end 322 of the tubular body 320. The closed loops 360 and the formation of the closed loops 368 can be similar to the closed loops 160 described above. It should be understood that the anti-migration features 350 and the longitudinally elongated closed loops 368 can be arranged in any arrangement, such as every second, third, fourth, or fifth loop is an anti-migration feature 350 and the remaining loops are longitudinally elongated closed loops 368. In some cases, each anti-migration loop 360 can be circumferentially positioned between adjacent ones of the longitudinally elongated closed loops 368. Additionally, the anti-migration features 350 and the longitudinally elongated closed loops 368 can form an irregular pattern around the open end of the stent 300. The anti-migration feature 350 may extend from the first open end 322 at an angle (such as an oblique angle or a perpendicular angle) relative to the central longitudinal axis and / or the outer surface of the tubular body 320 of the stent 100. Figure 3 As shown, in some cases, the closed loop 360 defining the anti-migration feature 350 can extend toward an end 324 of the stent 300 opposite the longitudinal elongated loop 368. In other cases, the closed loop 360 defining the anti-migration feature 350 can extend toward the same end 322 of the stent 300 as the longitudinal elongated loop 368. In some cases, the anti-migration feature 350 can extend from about 20 degrees to about 60 degrees relative to the outer surface of the tubular body 320. In some cases, the angle θ can be between about 10 degrees and about 160 degrees, between about 100 degrees and about 160 degrees, between about 100 degrees and about 140 degrees, between about 90 degrees and about 120 degrees, between about 20 degrees and about 90 degrees, between about 30 degrees and about 80 degrees, between about 20 degrees and about 45 degrees, etc. The plurality of anti-migration features 350 can be biased in an extended angled position when unconstrained and / or when the stent is deployed to an expanded configuration.

[0060] In some cases, the first end 352 or base of each anti-migration ring 360 and each longitudinally elongated ring 368 at the first end 322 of the stent 300 can be arranged at a single circumferential row located at the intersection of the lines forming the tubular body 320 at the first end 322 of the stent 300. In other words, the intersection of the plurality of anti-migration rings 360 and longitudinally extending rings 368 at one end of the stent can be located at a single longitudinal position circumferentially around the tubular body 320. The second free ends 354 of the anti-migration rings 360 can extend from the circumferential row at the base end 322 in a first longitudinal direction, while the second free ends 354 of the longitudinally extending rings 368 can extend from the circumferential row at the base end 322 in a second, opposite longitudinal direction.

[0061] In the illustrated embodiment, the first open end 322 is substantially cylindrical, wherein the outer diameter from the first open end 322 to the second flared region 329 adjacent the second open end 324 remains constant. Alternatively, the entire tubular body 320 may be cylindrical with a constant outer diameter, similar to Figure 1A The bracket 100 is shown.

[0062] Figures 4 to 8 Stents 400 , 500 , 600 , 700 , 800 with various arrangements of anti-migration features 450 , 550 , 650 , 750 , 850 are shown. Figure 4 The stent 400 shown includes a first portion of an anti-migration feature 450 (formed as a closed loop 460) coupled to the stent 400 adjacent to the first open end 422 and extending toward an opposite second open end 424 at an acute angle relative to the outer surface of the tubular body 420. A second portion of the anti-migration feature 450 (formed as a closed loop 460) is coupled to the tubular body 420 adjacent to the second open end 424 and extending toward the first open end 422 at an acute angle relative to the outer surface of the tubular body 420. Each of the closed loops 460 can be formed by one or more or more wires forming the interwoven structure of the tubular body 420. In the illustrated embodiment, the first and second portions of the anti-migration feature 450 extend toward the first or second open end 422, 424 at an angle of about 20 to 30 degrees relative to the central longitudinal axis or outer surface of the tubular body 420. However, in other cases, as discussed above, the anti-migration feature 450 can extend at any desired angle. The plurality of anti-migration features 450 can be biased into an extended angled position when unconstrained and / or when the stent is deployed to an expanded configuration. In some embodiments, the tubular body 420 can include one or more elongated closed loops 468 extending from either or both of the first open end 422 and the second open end 424. These elongated closed loops 468 can extend parallel to a central longitudinal axis extending through the tubular body 420. In other embodiments, the elongated closed loops 468 can extend at an angle to the longitudinal axis that is different from the closed loops 460 and thereby form additional anti-migration features. Figure 4 As shown, the anti-migration closed loop 460 at the first end 422 of the stent 400 can extend toward the second end 424, while the longitudinally elongated closed loop 468 at the first end 422 extends toward the first end 422 and thus extends in a direction substantially opposite to the anti-migration closed loop 460 at the first end 422. Alternatively, the anti-migration closed loop 460 at the second end 424 of the stent 400 can extend toward the first end 422, while the longitudinally elongated closed loop 468 at the second end 424 extends toward the second end 424 and thus extends in a direction substantially opposite to the anti-migration closed loop 460 at the second end 424.

[0063] In some cases, the first end 452 or base of each anti-migration closed loop 460 and each longitudinally elongated loop 468 at the first end 422 and / or the second end 424 of the stent 400 can be arranged at a single circumferential row at the intersection of the lines forming the tubular body 420 at the first end 422 of the stent 400 or the second end 424 of the stent 400. In other words, the intersection of the plurality of anti-migration loops 460 and the longitudinally extending loops 468 at one end of the stent can be located at a single longitudinal position circumferentially around the tubular body 420. The second free ends 454 of the anti-migration loops 460 can extend from the circumferential row at the base end 422 in a first longitudinal direction, while the second free ends 454 of the longitudinally extending loops 468 can extend from the circumferential row at the base end 422 in a second, opposite longitudinal direction.

[0064] Figure 5 The stent 500 shown includes a first open end 522, a second open end 524, and a plurality of anti-migration features 550 extending at various angles at the two open ends. In some cases, the first end 522 and / or the second end 524 can be a flared end having an outer diameter greater than the outer diameter of the middle region of the tubular body 520. Figure 5 As shown, a first portion of the anti-migration features adjacent to the first open end 522 may include an anti-migration feature 550a (e.g., closed loop 560) extending from a base 552 of the closed loop 560 in a first longitudinal direction, and an anti-migration feature 550b (e.g., closed loop 560) extending from the base 552 of the closed loop 560 in a second, opposite longitudinal direction. In some cases, the anti-migration feature 550a extending away from the middle region of the stent 500 may extend at an angle greater than 90 degrees (e.g., between 100 degrees and 130 degrees) relative to the outer surface of the tubular body 520, and the anti-migration feature 550b extending toward the middle region of the stent 500 may extend at an angle less than 90 degrees (e.g., between 20 degrees and 85 degrees) relative to the outer surface 520 of the tubular body. The formation of the anti-migration feature 550 (i.e., closed loop 560) may be similar to other anti-migration features described herein. The plurality of anti-migration features 550 can be biased into an extended, angled position when unconstrained and / or when the stent is deployed to an expanded configuration.

[0065] In some cases, the first end 552 or base of each anti-migration closed loop 560 and each longitudinally elongated loop 568 at the first end 522 and / or the second end 524 of the stent 500 can be arranged at a single circumferential row at the intersection of the lines forming the tubular body 520 at the first end 522 of the stent 500 or the second end 524 of the stent 500, respectively. In other words, the intersection of the plurality of anti-migration loops 560 and the longitudinally extending loops 568 at one end of the stent can be located at a single longitudinal position circumferentially around the tubular body 520. The second free ends 554 of the anti-migration loops 560 can extend from the circumferential row at the base end 522 in a first longitudinal direction, while the second free ends 554 of the longitudinally extending loops 568 can extend from the circumferential row at the base end 522 in a second, opposite longitudinal direction.

[0066] Figure 6 The stent 600 shown includes a first flared end 627 adjacent to the first open end 622 and a second flared end 629 adjacent to the second open end 624. A plurality of elongated loops forming a vertex at the first open end 622 extend substantially parallel to the longitudinal axis of the tubular body 620 at the first open end 622. The stent 600 also includes a plurality of anti-migration features 650 in the middle region of the tubular body 620. The anti-migration features 650 can be formed as closed loops 660, similar to other anti-migration features described herein. The anti-migration features 650 can include a first portion in the anti-migration features 650a extending toward the first open end 622, and a second portion in the anti-migration features 650b extending toward the second open end 624. As shown, the first and second portions in the anti-migration features 650a and 650b alternate around the circumference of the tubular body 620. Each of the anti-migration features 650a, 650b can extend at an acute angle (such as between 10 degrees and 80 degrees) relative to the outer surface of the tubular body 620. In some embodiments, the anti-migration features 650a, 650b can each extend at a different angle.The plurality of anti-migration features 650a, 650b can be biased into an extended angled position when unconstrained and / or when the stent is deployed to an expanded configuration.

[0067] In some cases, the first end 652 or base of each anti-migration feature 650a (e.g., closed loop 660) extending toward the first end 622 and each anti-migration feature 650b (e.g., closed loop 660) extending toward the second end 624 can be arranged at a single circumferential row of intersections of lines forming the tubular body 620. In other words, the intersections of the plurality of anti-migration loops 66 extending in two longitudinal directions can be located at a single longitudinal position circumferentially around the tubular body 620. The second free ends 654 of the anti-migration features 650a can extend in a first longitudinal direction from the circumferential row of base end 622 toward the first end 622, while the second free ends 654 of the anti-migration features 650b can extend in a second, opposite longitudinal direction from the circumferential row of base end 622 toward the second end 624.

[0068] The anti-migration features 650a, 650b can be formed by radially extending loops in the wire forming the tubular body 620, with the loops extending radially outward from the outer surface of the tubular body 620. The wire loops can be closed loops in which the wire crosses over itself at the base of the loop located in the tubular body 620 before entering the interlaced structure forming the tubular body 620. In some cases, the base of the loop (e.g., the intersection) can be welded so that the loop forming the anti-migration features 650a, 650b does not expand or decrease in size. In other embodiments, the anti-migration features 650a, 650b can be formed by separately formed wire loops and attached to the tubular body 620 at the intersection, such as by welding, so that tension or compression forces on the loops do not reduce the outer diameter of the tubular body 620 or change its length. In some cases, the wire forming the wire loop may not cross over itself at the base of the wire loop, but rather two sections of the wire may enter the interlaced structure forming the tubular body 620 at spaced-apart locations. In some cases, two wire segments may be welded to additional wires forming tubular body 620 at spaced-apart locations where the wire segments enter the interwoven structure forming tubular body 620 .

[0069] Figure 7 The bracket 700 shown has Figure 5 and Figure 6 The combination of features of stents 500 and 600 shown, wherein a first portion of anti-migration feature 750 is adjacent to first open end 722, a second portion of anti-migration feature 750 is adjacent to second open end 724, and a third portion of anti-migration feature 750 is in the middle region of stent 700. The above discussion is applicable to Figure 7Embodiment. The anti-migration feature can be formed by a closed loop 760, similar to the configuration of other closed loops described herein. The closed loop 760 in the middle region can include a first portion in the anti-migration feature 750a extending in the first longitudinal direction, and a second portion in the anti-migration feature 750b extending in the second opposite longitudinal direction. Similarly, the closed loop 760 at the first open end 722 can include a first portion extending in the first longitudinal direction and a second portion extending in the second opposite longitudinal direction, and / or the closed loop 760 at the second open end 724 can include a first portion extending in the first longitudinal direction and a second portion extending in the second opposite longitudinal direction. In each of the first, second, and third portions, the anti-migration feature 750 can extend at any desired oblique angle (e.g., acute angle or obtuse angle) or vertical angle with the central longitudinal axis or outer surface of the stent 700. For example, in some cases, the closed loop 760 can extend toward the first open end 722 or the second open end 724 at an angle of 20 to 120 degrees relative to the outer surface of the stent. The plurality of anti-migration features 750 can be biased in an extended angled position when unconstrained and / or when the stent is deployed to an expanded configuration. In some cases, the first and second portions of the anti-migration features can be disposed at a first flared end region at the first end 722 and a second flared end region at the second end 724, respectively. Each of the anti-migration features 750 can extend at the same or different angles.

[0070] Figure 8 A stent 800 is shown having a first open end 822 with a first flared end region 827 and a second open end 824 with a second flared end region 829, each open end being devoid of any anti-migration features. The first open end 822 and / or the second open end 824 may include one or more elongated rings forming an apex at the first open end 822 and extending substantially parallel to the longitudinal axis of the stent 800. The stent 800 also includes a plurality of anti-migration features 850 that may be disposed on an intermediate region of the tubular body 820 between the first and second open ends 822, 824. The anti-migration features 850 may be formed as closed loops 860, similar to other anti-migration features described herein. The anti-migration features 850 may be present in a plurality of separate groups spaced apart from one another in the longitudinal direction, wherein each group includes a first portion of the anti-migration features 850 (e.g., closed loops 860) extending toward the first open end 822, and a second portion of the anti-migration features 850 (e.g., closed loops 860) extending toward the second open end 824. As Figure 8As shown, the anti-migration features 850 can alternate directions. The anti-migration features 850 can extend at any oblique angle (e.g., acute or obtuse) or perpendicular angle (e.g., 20 to 120 degrees relative to the outer surface of the stent) to the central longitudinal axis or outer surface of the stent 800 toward the first open end 822 or the second open end 824. Each of the anti-migration features 850 can extend at the same or different angles. Multiple anti-migration features 850 can be biased in an extended angled position when unconstrained and / or when the stent is deployed to an expanded configuration.

[0071] In some cases, with respect to the first set of anti-migration features 850 at a first location along the middle region of the stent 800, the first end 852 or base of each anti-migration feature 850 (e.g., closed loop 860) extending toward the first end 822 and each anti-migration feature 850 (e.g., closed loop 860) extending toward the second end 824 can be arranged at a single circumferential row of intersections of lines forming the tubular body 820. In other words, the intersection of the plurality of anti-migration loops 860 extending in two longitudinal directions can be located at a first longitudinal location circumferentially around the tubular body 820. The second free ends 854 of the first portions of the anti-migration features 850 can extend in a first longitudinal direction from the circumferential row of the base end 822 toward the first end 822, while the second free ends 854 of the second portions of the anti-migration features 850 can extend in a second, opposite longitudinal direction from the circumferential ring of the base end 822 toward the second end 824.

[0072] The stent 800 can include a second set of anti-migration features 850 located at a second location along the middle region of the stent 800 that is longitudinally spaced apart from the first set of anti-migration features 850. With respect to the second set of anti-migration features at the second location along the middle region of the stent 800, the first end 852 or base of each anti-migration feature 850 (e.g., closed loop 860) extending toward the first end 822 and each anti-migration feature 850 (e.g., closed loop 860) extending toward the second end 824 can be arranged at a single circumferential row of intersections of lines forming the tubular body 820. In other words, the intersection of the plurality of anti-migration loops 860 extending in two longitudinal directions can be located circumferentially around the tubular body 820 at a first longitudinal location. The second free end 854 of the first portion in the anti-migration feature 850 can extend in a first longitudinal direction from the circumferential row of the base end 822 toward the first end 822, while the second free end 854 of the second portion in the anti-migration feature 850 can extend in a second, opposite longitudinal direction from the circumferential ring of the base end 822 toward the second end 824.

[0073] Fig.9A and Fig. 9BA portion of a stent 900 is shown in which a plurality of anti-migration features 950 extend from a first open end 922 of a tubular body 920 of the stent 900. Each of the anti-migration features 950 can be defined by a looped portion of a wire 940 extending between two intersection points 926 as the wire 940 extends outwardly from the tubular body 920 of the stent 900. Thus, as shown in FIG. Fig.9A As shown, the anti-migration feature 950 can be formed by a wire 940 extending between two circumferentially spaced intersections 926. The wire 940 can be welded to additional wires forming the interwoven structure of the tubular body 920 at the two intersections 926 to prevent any tensile or compressive forces applied to the anti-migration feature 950 from reducing the outer diameter of the stent 900 or elongating the stent 900. The anti-migration feature 950 can extend radially outward from the outer surface of the tubular body 920 at any desired angle relative to the central longitudinal axis and / or the outer surface of the tubular body 920, such as an oblique angle (e.g., an acute angle or an obtuse angle) or a perpendicular angle. In some cases, the angle can be an obtuse angle, wherein the anti-migration feature 950 extends toward the first open end 922. In other cases, if desired, the angle can be an acute angle, wherein the anti-migration feature 950 bends back toward the opposite second open end of the stent 900 (not shown). In other cases, the angle can be a perpendicular angle. In some cases, the angle can be between about 10 degrees and about 160 degrees, between about 100 degrees and about 160 degrees, between about 100 degrees and about 140 degrees, between about 90 degrees and about 120 degrees, between about 20 degrees and about 90 degrees, between about 30 degrees and about 80 degrees, between about 20 degrees and about 45 degrees, etc. The anti-migration feature 950 can form a petal structure when viewed from the end, such as Fig. 9B As shown. The plurality of anti-migration features 950 can be biased in an extended angled position relative to the tubular body 920 when unconstrained and / or when the stent is deployed to an expanded configuration. If desired, the stent 900 can include a first flared region 927 adjacent to the first open end 922. Fig. 9B As shown, the first open end 922 may include a plurality of anti-migration features 950 arranged about the circumference of the tubular body 920 and extending radially outward therefrom.

[0074] Fig.10A stent 1000 having an alternative anti-migration structure is shown. In this embodiment, all of the closed loops 1060 at the first open end 1022 of the stent 1000 are substantially enlarged closed loops 1060 that define the anti-migration feature 1050. In some cases, the enlarged closed loops 1060 can be formed by looped portions of a single wire that cross themselves at the intersection of the bases of the closed loops 1060. In some embodiments, the enlarged closed loops 1060 can each have an outermost diameter that is at least 2 times, at least 3 times, or at least 4 times the outer diameter of the tubular body 1020 of the stent 1000. In some cases, the enlarged closed loops 1060 can have a length that is at least half or more of the outer diameter of the tubular body 1020 forming the stent 1000, or a length that is equal to or greater than the outer diameter of the tubular body 1020 of the stent 1000. The enlarged closed loops 1060 can be elliptical or polygonal, such as defining an octagon. The enlarged closed loop 1060 can extend from the first open end 1022 at any desired angle relative to the central longitudinal axis and / or outer wall of the tubular body 1020. The plurality of anti-migration features 1050 can be biased into an extended angled position when unconstrained and / or when the stent is deployed to an expanded configuration.

[0075] like Fig.11A As shown, another embodiment of the stent 1100 can have a plurality of enlarged closed loops 1160 extending from a first open end 1122 and a second open end 1124. The enlarged closed loops 1160 can extend radially outward from the tubular body 1120 forming the stent 1100 at any desired angle, such as about 45 degrees to about 90 degrees, to the longitudinal axis XX extending through the stent 1100. In some embodiments, each end of the enlarged closed loops 1160 can extend from the intersection 1126. The enlarged closed loops 1160 can be formed by the wire 1140 forming the tubular body 1120. In other embodiments, the enlarged closed loops 1160 can be formed separately and fixed to the tubular body 1120. Whether the enlarged closed loops 1160 are formed by the wire 1140 forming the tubular body 1120, or are formed separately and fixed to the tubular body 1120, the intersection 1126 can be welded, and the enlarged closed loops extend from the intersection 1126. This prevents any pulling or compressive forces applied to the enlarged closed loop 1160 from reducing the diameter of the tubular body 1120 or elongating the tubular body 1120. Therefore, the enlarged closed loop 1160 does not form a retrieval or removal structure. The enlarged closed loop 1160 can be biased in an extended angled position when unconstrained and / or when the stent is deployed to the expanded configuration.

[0076] The stent 1100 can be used as a conduit for establishing fluid communication between adjacent body cavities. For example, the stent 1100 can be used as a drainage stent, fistula, anastomosis device, etc. Fig.11A and Fig. 11B As shown, the enlarged closed loop 1160 can be configured to engage two adjacent body cavities 1105, 1107 and hold them in place for fluid to flow therebetween. In one example, the stent 1100 can be used to drain bile and / or gallstones from the gallbladder to the duodenum. In another example, the stent 1100 can be used in endoscopic surgery, such as a gastrojejunostomy, in which the stent 1100 can be used to create an anastomosis between the stomach 1105 and the small intestine 1107 to form a duodenal bypass. The details of the surgical procedure are described in U.S. Patent Application Publication No. 2019 / 0298401, which is incorporated herein by reference in its entirety.

[0077] In all of the above embodiments, the anti-migration feature 150, 250, 350, 450, 550, 650, 750, 750, 950, 1050, 1150 can be formed by a single wire having opposite ends fixed to the tubular body to form a closed loop. The closed loop anti-migration feature can be fixed to the tubular body so that any pulling or compressive force applied to the anti-migration feature does not cause the diameter of the tubular body to be reduced or elongated or shortened. Therefore, the anti-migration feature is not intended to be used as a retrieval element. Alternatively, the anti-migration feature can be formed by multiple segments of multiple wires extending from the interwoven structure of the tubular body of the stent. In some cases, the ends of the multiple wires are welded or otherwise fixed together to form a closed loop, wherein the base end of the closed loop is fixed to the tubular body. The base end of each closed loop can be located at a single intersection in the tubular body, or the base end of each ring can be fixed to an adjacent intersection. In all of the above embodiments, the anti-migration feature 150, 250, 350, 450, 550, 650, 750, 750, 950, 1050, 1150 can be moved between a delivery configuration and a deployment configuration, in which the anti-migration feature extends substantially parallel to the central longitudinal axis of the tubular body of the stent, and in the deployment configuration, the anti-migration feature extends radially away from the central longitudinal axis, wherein the anti-migration feature is biased in the deployment configuration when unconstrained and / or when the stent is deployed to an expanded configuration. The anti-migration feature can be maintained in the delivery configuration by an outer sheath disposed on the stent. Releasing the stent from the outer sheath allows the anti-migration feature to expand to its angled configuration. In other embodiments, a suture or wire can be passed through the anti-migration feature to maintain it in the delivery configuration. During delivery, the suture or wire is removed to allow the anti-migration feature to return to its biased angled configuration.

[0078] Any of the above-mentioned stents 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100 may include a cover 170, as described with reference to Figure 1 The bracket 100 is shown as described.

[0079] It should be understood that any angles described in association with the above figure are merely illustrative, and other angles of the closed loop anti-migration feature can be envisioned. The materials that can be used for the various components of the stent 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100 and various elements thereof may include those materials that are commonly associated with medical devices. For simplicity, the discussion below refers to the stent 100 (and the variants, systems or components disclosed herein). However, this is not intended to limit the devices and methods described herein, because the discussion can be applied to other elements, components, parts or devices disclosed herein.

[0080] In some embodiments, stent 100 (and variations, systems, or components thereof disclosed herein) can be made of metals, metal alloys, ceramics, zirconium oxide, polymers (some examples of which are disclosed below), metal-polymer composites, combinations thereof, or the like, or other suitable materials. Some examples of suitable metals and metal alloys include stainless steels, such as 444V, 444L, 314LV stainless steel; mild steel; nickel-titanium alloys, such as linear elastic and / or superelastic nitinol; cobalt-chromium alloys, titanium and its alloys, aluminum oxide, metals with diamond-like coatings (DLC) or titanium nitride coatings; other nickel alloys, such as nickel-chromium-molybdenum alloys (e.g., UNS: N06625, such as 625, UNS: N06022, such as C- UNS: N10276, such as other alloys, etc.), nickel-copper alloys (e.g. UNS: N04400, such as 400, 400, 400, etc.), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R44035, such as MP35- etc.), nickel-molybdenum alloys (e.g., UNS: N10665, such as ), other nickel-chromium alloys, other nickel-molybdenum alloys, other nickel-cobalt alloys, other nickel-iron alloys, other nickel-copper alloys, other nickel-tungsten or tungsten alloys, etc.; cobalt-chromium alloys; cobalt-chromium-molybdenum alloys (e.g., UNS: R44003, such as etc.); platinum-rich stainless steel; titanium; platinum; palladium; gold; combinations thereof; etc. or any other suitable material.

[0081] As mentioned herein, within the family of commercially available nickel-titanium or Nitinol alloys, there is a category designated as "linear elastic" or "non-superelastic", although it may be chemically similar to conventional shape memory and super-elastic varieties and may exhibit different and useful mechanical properties. Linear elastic and / or non-superelastic Nitinol may be distinguished from superelastic Nitinol because linear elastic and / or non-superelastic Nitinol does not exhibit a large amount of "superelastic plateau" or "landmark area" in its stress / strain curve as superelastic Nitinol does. In contrast, in linear elastic and / or non-superelastic Nitinol, as recoverable strain increases, stress continues to increase in a substantially linear or slightly, but not necessarily completely, linear relationship until plastic deformation begins or at least increases in a more linear relationship than the superelastic plateau and / or landmark area that can be seen with super-elastic Nitinol. Therefore, for the purposes of the present invention, linear elastic and / or non-superelastic Nitinol may also be referred to as "substantially" linear elastic and / or non-superelastic Nitinol.

[0082] In some cases, linear elastic and / or non-superelastic Nitinol can also be distinguished from superelastic Nitinol because linear elastic and / or non-superelastic Nitinol can accept strains up to about 2 to 5% while remaining substantially elastic (e.g., before plastic deformation), while superelastic Nitinol can accept strains up to about 8% before plastic deformation. These two materials can be distinguished from other linear elastic materials, such as stainless steel, which can only accept strains of about 0.2 to 0.44% before plastic deformation (which can also be distinguished based on their composition).

[0083] In some embodiments, the linear elastic and / or non-superelastic nickel-titanium alloy is an alloy that does not show any martensite / austenite phase transformation detectable by differential scanning calorimetry (DSC) and dynamic metal thermal analysis (DMTA) over a wide temperature range. For example, in some embodiments, in a linear elastic and / or non-superelastic nickel-titanium alloy, there may be no martensite / austenite phase transformation detectable by DSC and DMTA analysis in the range of about -60 degrees Celsius (°C) to about 120°C. Therefore, the mechanical bending properties of this material are generally inert to temperature effects over this very wide temperature range. In some embodiments, the mechanical bending properties of the linear elastic and / or non-superelastic nickel-titanium alloy at ambient or room temperature are substantially the same as the mechanical properties at body temperature, for example, it does not show a superelastic plateau and / or signature zone. For example, over a wide temperature range, the linear elastic and / or non-superelastic nickel-titanium alloy maintains its linear elastic and / or non-superelastic characteristics and / or properties.

[0084] In some embodiments, the linear elastic and / or non-superelastic nickel-titanium alloy may contain nickel in the range of about 50 to about 60 weight percent, with the remainder being substantially titanium. In some embodiments, the composition contains nickel in the range of about 54 to about 57 weight percent. An example of a suitable nickel-titanium alloy is FHP-NT alloy commercially available from Furukawa TechnoMaterial Co. of Kanagawa, Japan. Other suitable materials may include ULTANIUM TM (available from Neo-Metrics) and GUM METAL TM (Available from Toyota.) In some other embodiments, superelastic alloys, such as superelastic Nitinol, can be used to achieve the desired properties.

[0085] In at least some embodiments, part or all of the stent 100 (and its variants, systems or components disclosed herein) may also be doped with, made of or otherwise include radiopaque materials. Radiopaque materials are understood to be capable of producing relatively bright images on a fluoroscopic screen or with another imaging technique during medical surgery. This relatively bright image helps the user determine the position of the stent 100 (and its variants, systems or components disclosed herein). Some examples of radiopaque materials may include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloys, polymer materials loaded with radiopaque fillers, and the like. Additionally, other radiopaque marker bands and / or coils may also be incorporated into the design of the stent 100 (and its variants, systems or components disclosed herein) to achieve the same results.

[0086] In some embodiments, stent 100 (and variations, systems, or components thereof disclosed herein) and / or portions thereof may be made of or include a polymer or other suitable material. Some examples of suitable polymers may include polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), polyoxymethylene (POM, e.g., available from DuPont), polyoxymethylene (POM ... ), polyether block esters, polyurethanes (e.g., polyurethane 85A), polypropylene (PP), polyvinyl chloride (PVC), polyether esters (e.g., available from DSM Engineering Plastics ), ether or ester based copolymers (e.g., butylene / poly(alkylene ether) phthalate and / or other polyester elastomers such as those commercially available from DuPont ), polyamide (e.g., available from Bayer Or available from Elf Atochem ), elastomeric polyamides, block polyamide / ethers, polyether block amides (PEBA, for example, available under the trade name purchased), ethylene vinyl acetate copolymer (EVA), silicone resin, polyethylene (PE), Marlex high-density polyethylene, Low-density polyethylene, linear low-density polyethylene (e.g. ), polyester, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polytrimethylene terephthalate, polyethylene naphthalate (PEN), polyetheretherketone (PEEK), polyimide (PI), polyetherimide (PEI), polyphenylene sulfide (PPS)), polyphenylene oxide (PPO), polyparaphenylene terephthalamide (e.g., ), polysulfone, nylon, nylon-12 (such as available from EMS American Grilon ), perfluoro(propyl vinyl ether) (PFA), ethylene vinyl alcohol, polyolefins, polystyrene, epoxy resins, polyvinylidene chloride (PVdC), poly(styrene-b-isobutylene-b-styrene) (e.g., SIBS and / or SIBS 50A), polycarbonate, ionomers, polyurethane silicone copolymers (e.g., Elast- or from AdvanSource Biomaterials ), biocompatible polymers, other suitable materials or mixtures, combinations, copolymers, polymer / metal composites, etc. In some embodiments, the sheath can be mixed with a liquid crystal polymer (LCP). For example, the mixture can contain up to about 6% LCP.

[0087] In some embodiments, stent 100 (and variations, systems, or components thereof disclosed herein) may include and / or be treated with a suitable therapeutic agent. Some examples of suitable therapeutic agents may include anticoagulants (such as heparin, heparin derivatives, urokinase, and PPack (dextrophenylalanine proline arginine chloromethyl ketone); antiproliferative agents (such as enoxaparin, angiopeptin, monoclonal antibodies capable of blocking smooth muscle cell proliferation, hirudin, and acetylsalicylic acid); anti-inflammatory drugs (such as dexamethasone, prednisolone, corticosterone, budesonide, estrogen, sulfasalazine, and mesalazine); anti-tumor / antiproliferative / anti-mitotic agents (such as paclitaxel, 5-fluorouracil, cisplatin, vinblastine, vincristine, epothilone, endostatin, angiostatin, and thymidine kinase inhibitors); anesthetics (such as lidocaine, bupivacaine, and ropivacaine); anticoagulants (such as D-Phe-Pro-Arg chloromethyl ketone); ketones, compounds containing RGD peptides, heparin, antithrombin compounds, platelet receptor antagonists, antithrombin antibodies, antiplatelet receptor antibodies, aspirin, prostaglandin inhibitors, platelet inhibitors and tick antiplatelet peptides); vascular cell growth promoters (such as growth factor inhibitors, growth factor receptor antagonists, transcription activators and translation promoters); vascular cell growth inhibitors (such as growth factor inhibitors, growth factor receptor antagonists, transcription inhibitors, translation inhibitors, replication inhibitors, inhibitory antibodies, antibodies to growth factors, bifunctional molecules composed of growth factors and cytotoxins, bifunctional molecules composed of antibodies and cytotoxins); cholesterol-lowering agents; vasodilators; and agents that interfere with endogenous vasoactive mechanisms.

[0088] It should be understood that the present invention is in many respects merely illustrative. Changes may be made in details, particularly matters of shape, size, and arrangement of steps, without exceeding the scope of the present invention. To the extent appropriate, this may include using any of the features of an example embodiment used in other embodiments. Of course, the scope of the present invention is defined by the language of the appended claims.

Claims

1. A bracket, comprising: a tubular body formed from the interwoven wires, the tubular body having a first open end, an opposing second open end, and a central longitudinal axis extending therebetween, the tubular body being movable between a radially compressed state and a radially expanded state; as well as a plurality of anti-migration features, each of the plurality of anti-migration features having a first end positioned at an outer surface of the tubular body and a second end extending radially outward from the outer surface of the tubular body; Wherein each of the plurality of anti-migration features is defined by a closed loop of one or more of the interwoven threads, wherein a base of the closed loop is located on the outer surface of the tubular body. 2 . The stent of claim 1 , wherein the base of the closed loop comprises intersections of the one or more interwoven threads forming the closed loop.

3. The stent of claim 2, wherein the one or more interwoven wires are welded at the intersections.

4. The stent of any of the preceding claims, wherein any tensile or compressive forces applied to any of the plurality of anti-migration features do not reduce the outer diameter of the tubular body or axially lengthen or shorten the tubular body.

5. The stent of any of the preceding claims, wherein a first portion of the plurality of anti-migration features is coupled to the tubular body adjacent the first open end and extends toward the second open end at an acute angle relative to the outer surface of the tubular body.

6. The stent of claim 5, wherein a second portion of the plurality of anti-migration features is coupled to the tubular body adjacent the second open end and extends at an acute angle toward the first open end.

7. A stent according to claim 1, wherein a first portion of the plurality of anti-migration features is connected to a middle region of the tubular body and extends at an acute angle toward the first open end, and a second portion of the plurality of anti-migration features is connected to the middle region of the tubular body and extends at an acute angle toward the second open end.

8. The stent of claim 7, wherein the base of each anti-migration feature of the first portion and the base of each anti-migration feature of the second portion are circumferentially spaced apart at a single longitudinal location along the tubular body.

9. The stent of claim 1, wherein the closed loop defining the plurality of anti-migration features is located at the first open end and extends radially outward from the tubular body.

10. The stent of claim 9, further comprising a plurality of elongated closed loops at the first open end extending substantially parallel to the central longitudinal axis.

11. The stent of claim 10, wherein the plurality of elongated closed loops are interposed between adjacent ones of the closed loops defining the plurality of anti-migration features.

12. A stent according to any one of the preceding claims, wherein each closed loop is formed from a plurality of interwoven wires, wherein the ends of the plurality of interwoven wires are welded around the perimeter of the closed loop.

13. The stent of claim 12, wherein each closed loop is formed by segments of four of the interwoven wires that together define a perimeter of the closed loop.

14. A bracket comprising: a tubular body formed from the interwoven wires, the tubular body having a first open end, an opposing second open end, and a central longitudinal axis extending therebetween, the tubular body being movable between a radially compressed state and a radially expanded state; as well as A plurality of anti-migration features each having a first end welded to one or more intersections of the one or more interwoven wires forming the tubular body and a second end extending radially outward from an outer surface of the tubular body.

15. A bracket comprising: a radially expandable tubular body formed from the interwoven wires, the tubular body having a first open end, an opposing second open end, and a central longitudinal axis extending therebetween, the tubular body being movable between a radially compressed state and a radially expanded state; as well as a plurality of anti-migration features at the first open end, each of the plurality of anti-migration features having a first end positioned at the outer surface of the tubular body and a second end extending radially outward from the outer surface of the tubular body; Wherein each of the plurality of anti-migration features is formed by a plurality of the interwoven threads arranged in a closed loop, wherein ends of the plurality of threads are arranged around a perimeter of the closed loop.

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