Stent with anti-migration features

Abstract

A stent and / or intraluminal implant for spanning two non-adherent structures / tissues. An exemplary stent may include an elongate tubular body having a scaffold forming a plurality of cells and a coating disposed on an outer surface of the elongate tubular body. The coating may include a first microporous layer and a macroporous layer including a plurality of loops disposed on the microporous layer.

Description

[Technical Field]

[0001] The present disclosure relates to medical devices, methods for manufacturing medical devices, and uses of medical devices. More particularly, the present disclosure relates to stents for placement in a body lumen or transluminally, and related methods. [Background technology]

[0002] A wide variety of intracorporeal medical devices have been developed for medical applications, such as surgical and / or intravascular applications. In some cases, physicians can use stents to create a temporary opening between the gallbladder and the gastrointestinal (GI) tract, thereby allowing drainage of fluid from the gallbladder in the event of a ductal obstruction. Without this technology, other solutions include laparoscopic or percutaneous removal of the gallbladder, which poses a high risk for elderly, critically ill, and patients with coexisting medical conditions. There is a continuing need for known stents, intraluminal implants, and / or transluminal implants to provide alternative configurations for stents, intraluminal implants, and / or transluminal implants. Summary of the Invention

[0003] The present disclosure provides design, material, manufacturing methods and use alternatives for medical devices. An exemplary medical device may include a stent. In a first embodiment, a stent may comprise an elongate tubular body having a scaffolding defining a plurality of cells, and a coating disposed on an exterior surface of the elongate tubular body, the coating may include a first microporous layer and a macroporous layer disposed on the microporous layer.

[0004] Alternatively or additionally to any of the above embodiments, in another embodiment the macroporous layer may include a columnar structure. Alternatively or additionally to any of the above embodiments, in another embodiment the macroporous layer may include a plurality of loops.

[0005] Alternatively or additionally to any of the above embodiments, in another embodiment the loops may be stacked one on top of the other to form columns. Alternatively or additionally to any of the above embodiments, in another embodiment the plurality of posts may extend radially from the outer surface of the microporous layer.

[0006] Alternatively or additionally to any of the above embodiments, in another embodiment, at least some of the plurality of posts may have longitudinal axes that extend at an oblique angle relative to the longitudinal axis of the elongate tubular body.

[0007] Alternatively or additionally to any of the above embodiments, in another embodiment at least some of the plurality of posts may extend at an acute angle between 0° and 90° relative to the longitudinal axis, and at least some of the plurality of posts may extend at an obtuse angle between 90° and 180° relative to the longitudinal axis.

[0008] Alternatively or additionally to any of the above embodiments, in another embodiment at least some of the plurality of posts may have free ends oriented towards a centrally located longitudinal post.

[0009] Alternatively or additionally to any of the above embodiments, in another embodiment the density of the plurality of pillars may increase towards the pillars located at the longitudinal center. Alternatively or additionally to any of the above embodiments, in another embodiment, one loop of the plurality of loops may be at least partially laterally spaced from a preceding loop.

[0010] Alternatively or additionally to any of the above embodiments, another embodiment may further include a second microporous layer disposed over the macroporous layer. In another embodiment, a stent may include an elongate tubular body having a scaffolding forming a plurality of cells and a covering extending over the scaffolding to cover the plurality of cells of the scaffolding, and a woven sleeve disposed over at least a portion of the elongate tubular body, the woven sleeve being fabricated from one or more interwoven filaments defining a plurality of open cells.

[0011] Alternatively or additionally to any of the above embodiments, in another embodiment, the entire length of the woven sleeve may be positioned between a first flange proximate a first end of the elongated tubular body and a second flange proximate a second end of the elongated tubular body.

[0012] Alternatively or additionally to any of the above embodiments, in another embodiment the fabric sleeve may be removably disposed over the elongate tubular body. Alternatively or additionally to any of the above embodiments, in another embodiment the fabric sleeve may be formed from a bioabsorbable textile material.

[0013] Alternatively or additionally to any of the above embodiments, in another embodiment the fabric sleeve may be formed from a synthetic fiber material. In another embodiment, a stent may include an elongate tubular body having a scaffolding forming a plurality of cells, a first polymer matrix disposed over the elongate tubular body, the first polymer matrix including a plurality of first fibers defining a plurality of pores and having a first density of the plurality of first fibers, and a second polymer matrix disposed over the elongate tubular body, the second polymer matrix including a plurality of second fibers defining a plurality of pores and having a second density of the plurality of second fibers, wherein the second density of fibers may be less than the first density of fibers.

[0014] Alternatively or additionally to any of the above embodiments, in another embodiment the first polymer matrix may be configured to prevent tissue ingrowth. Alternatively or additionally to any of the above embodiments, in another embodiment the second polymer matrix may be configured to promote tissue ingrowth.

[0015] Alternatively or additionally to any of the above embodiments, in another embodiment the plurality of first fibers and the plurality of second fibers may be electrospun. Alternatively or additionally to any of the above embodiments, in another embodiment the stent may further include a bioadhesive coating disposed on the second polymer matrix.

[0016] Alternatively or additionally to any of the above embodiments, in another embodiment, the diameter of the first plurality of fibers may be smaller than the diameter of the second plurality of fibers. In another embodiment, a stent may include an elongate tubular body having a scaffold forming a plurality of cells; a first polymer matrix disposed on the elongate tubular body, the first polymer matrix including a plurality of first fibers defining a plurality of pores and having a first density of the plurality of first fibers; and a hydrogel adhesive layer disposed on the first polymer matrix.

[0017] Alternatively or additionally to any of the above embodiments, in another embodiment the hydrogel advice layer may comprise gelatin, gelatin methacryloyl (GelMA), polyethylene glycol (PEG) based bioadhesive or chitosan.

[0018] In another embodiment, a stent may include an elongate tubular body having a scaffold forming a plurality of cells; a first polymer matrix disposed on the elongate tubular body, the first polymer matrix including a plurality of first fibers defining a plurality of pores and having a first density of the plurality of first fibers; and a hemostatic agent layer disposed on the first polymer matrix.

[0019] Alternatively or additionally to any of the above embodiments, in another embodiment the hemostat layer may include kaolin and sodium montmorillonite. The above summary of some embodiments is not intended to describe each disclosed embodiment or every implementation of the present disclosure, the following figures and detailed description more particularly exemplify these embodiments. [Brief explanation of the drawings]

[0020] The present disclosure will be more fully understood from consideration of the following detailed description of various embodiments in conjunction with the accompanying drawings, in which: [Figure 1] FIG. 1 is a side view of an exemplary stent. [Figure 2] 2 is a cross-sectional view of the exemplary stent of FIG. 1. [Figure 3] 2 is a schematic diagram of the exemplary stent of FIG. 1 deployed within the body. [Figure 4] FIG. 3 is an enlarged cross-sectional view of a portion of the exemplary stent of FIG. 2. [Figure 5] Schematic diagram of an exemplary pattern of a macroporous layer. [Figure 6] 1 is a schematic top view of an exemplary macroporous layer. [Figure 7A] 2 is a partial cross-sectional view of the stent of FIG. 1 having an alternative macroporous layer with an alternative columnar structure and an outer microporous layer. [Figure 7B] 2 is a partial cross-sectional view of the stent of FIG. 1 having an alternative macroporous layer and an outer microporous layer. [Figure 8A] 2 is a partial perspective view of a portion of the stent of FIG. 1 having an alternative macroporous layer. [Figure 8B] 2 is a partial perspective view of a portion of the stent of FIG. 1 having an alternative macroporous layer. [Figure 9A] 2 is a partial schematic cross-sectional view of the exemplary stent of FIG. 1 illustrating another exemplary arrangement of multiple struts. [Figure 9B] FIG. 9B is an enlarged view of a portion of the stent of FIG. 9A. [Figure 10] 2 is a partial schematic cross-sectional view of the exemplary stent of FIG. 1 showing another exemplary arrangement of multiple struts. [Figure 11A]Schematic top view of an exemplary polymer matrix. [Figure 11B] FIG. 2 is a schematic top view of another exemplary polymer matrix. [Figure 12] FIG. 3 is an enlarged cross-sectional view of a portion of the exemplary stent of FIG. 2 having an alternative coating. [Figure 13] 1 is a side view of an exemplary outer layer for use with a stent.

[0021] The present disclosure is susceptible to various modifications and alternative forms, details of which have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that aspects of the disclosure are not limited to the particular embodiments described. On the contrary, it is intended to cover all modifications, equivalents, and alternatives falling within the scope of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0022] For the following defined terms, these definitions shall be applied unless a different definition is given in the claims or elsewhere in this specification. All numerical values, whether explicitly stated or not, are assumed herein to be modified by the term "about." The term "about" generally refers to a range of numbers that one of ordinary skill in the art would consider equivalent to the recited value (i.e., having the same function or result). In many instances, the term "about" may be expressed as including numbers that are rounded to the nearest significant figure.

[0023] The recitation of numerical ranges by endpoints includes all numbers within that range (eg, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). Although certain preferred dimensions, ranges and / or values ​​for various components, features and / or specifications are disclosed, one of ordinary skill in the art motivated by this disclosure will understand that the desired dimensions, ranges and / or values ​​may deviate from those explicitly disclosed.

[0024] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally used in its sense including "and / or" unless the content clearly dictates otherwise.

[0025] The following detailed description should be read with reference to the drawings, in which like elements in different drawings are numbered the same. The detailed description and drawings are not necessarily to scale and depict exemplary embodiments and are not intended to limit the scope of the present disclosure. The exemplary embodiments shown are intended as examples only. Selected features of any exemplary embodiment may be incorporated into additional embodiments unless expressly stated to the contrary.

[0026] In some cases, physicians can use stents or transluminal implants to create an anastomosis, or temporary opening, between the gallbladder and the gastrointestinal (GI) tract, thereby allowing drainage of fluid from the gallbladder in the event of ductal obstruction. Without this technology, other solutions include laparoscopic or percutaneous removal of the gallbladder, which poses a high risk for elderly, critically ill, and patients with coexisting medical conditions. While this technology has significantly advanced patient care, challenges associated with transluminal drainage remain. For example, placing a stent between two non-adherent structures to form an anastomosis (e.g., gastrojejunostomy, hepaticogastrostomy, or gallbladder drainage into either the stomach or duodenum) is technically challenging due to a lack of tools for visualizing, stabilizing, and in some cases, distending the target site. These challenges can lead to the stent failing to create a hold between the two non-adherent structures / tissues. All of these challenges can lead to a failed procedure with serious complications. What is desired are devices and related methods that make the post-procedure process easier for patients and reduce long-term complications. While the present disclosure is discussed with respect to transluminal implants for creating an anastomosis, it should be understood that the devices described herein can also be intraluminal implants. Furthermore, the implant location is not limited to a particular anatomical location.

[0027] FIG. 1 shows a side view of an exemplary implant 10, such as a stent, without limitation. FIG. 2 shows a cross-sectional view of the exemplary stent 10 taken along line 2-2 in FIG. 1 . FIG. 3 shows a schematic diagram of the exemplary stent 10 deployed within a patient to form an anastomosis. In some cases, the stent 10 may be formed from an elongated tubular member 12. While the stent 10 is described as generally tubular, it is contemplated that the stent 10 may have any desired cross-sectional shape. The stent 10 may have a first or proximal end 14, a second or distal end 16, and an intermediate region 18 disposed between the first and second ends 14, 16. The stent 10 may have a lumen 20 extending from a first opening adjacent the first end 14 to a second opening adjacent the second end 16, thereby allowing fluids and the like to pass through the lumen.

[0028] Stent 10 may be radially expandable from a first radially contracted configuration (not explicitly shown) to a second radially expanded configuration as shown in Figures 1-3. Stent 10 may be structured to extend across and apply radially outward pressure to two non-adhered structures / tissues to create an opening or passage between the two non-adhered structures / tissues, thereby forming an anastomosis between two separate anatomical structures.

[0029] The tubular member 12 of the stent 10 may have a scaffold structure assembled from one or more interwoven filaments or struts 22. The scaffold structure may extend from the first end 14 to the second end 16 of the stent 10. For example, the scaffold structure, i.e., its filaments, may extend continuously from the first end 14 to the second end 16 of the stent 10. In some embodiments, the stent 10 may be formed of a single filament interwoven (e.g., braided) with itself to form the scaffold structure. In other embodiments, the stent 10 may be formed of several filaments interwoven (e.g., braided) to form the scaffold structure. Thus, in such cases, one or more of the filaments forming the scaffold structure may extend continuously from the first end 14 to the second end 16 of the stent 10. In yet another embodiment, the stent 10 may include a tubular member that has been laser cut to form the scaffold structure. The laser-cut tubular members may have open and / or closed cell geometries, including one or more interconnected struts formed from the tubular members as a monolithic structure. In such cases, the laser-cut tubular members forming the scaffolding structure may extend continuously from the first end 14 to the second end 16 of the stent 10.

[0030] In some cases, the inner and / or outer surfaces of the scaffolding of stent 10 may be entirely, substantially, or partially coated with a polymeric coating or layer 24, 26 (see, e.g., FIG. 2 ). For example, the coating or layer may extend through the open cells of the scaffolding to prevent tissue ingrowth into the lumen of stent 10. However, in some embodiments, one or both of the polymeric coatings 24, 26 may be omitted. For example, in some embodiments, stent 10 may include only an outer polymeric coating 26 on the outer surface of the scaffolding. In other embodiments, stent 10 may include only an inner polymeric coating 24 on the inner surface of the scaffolding. In some cases, the inner layer 24 and the outer layer 26 may be formed as a unitary structure. In other embodiments, the inner layer 24 and the outer layer 26 may be formed as separate layers. The inner layer 24 and the outer layer 26 may be formed from the same or different materials, as desired. As shown more clearly in FIG. 4 , which depicts an enlarged view of a portion of stent 10 shown in dashed lines in FIG. 2 , the inner layer 24 and / or the outer layer 26 may extend or be disposed within openings or interstice spaces defined between adjacent stent filaments or struts 22 of the scaffolding. It will be appreciated that because the inner layer 24 and the outer layer 26 extend outwardly and inwardly, respectively, the inner layer 24 and the outer layer 26 can form interface regions and / or contact spaces 23 (e.g., openings, cells, interstice spaces) in the wall of the scaffolding of stent 10. For example, the detailed view of FIG. 4 illustrates that both the inner layer 24 and the outer layer 26 may extend and form interface regions within openings 23 defined between adjacent stent struts 22. Additionally, the inner layer 24 and the outer layer 26 may extend between adjacent filaments or struts 22, thereby filling any spaces between adjacent filament or strut members 22 and preventing tissue ingrowth into the lumen of stent 10.

[0031] The scaffolding structure of stent 10, e.g., the filaments and / or struts, can be made from several different materials, such as, but not limited to, metals, metal alloys, shape memory alloys, and / or polymers, as desired, and it is contemplated that stent 10 can be expanded into a certain shape once properly positioned within the body. In some instances, materials may be selected to also allow stent 10 to be relatively easily removed. For example, stent 10 can be formed from alloys such as, but not limited to, Nitinol and Elgiloy®. Depending on the materials selected for construction, stent 10 may be self-expanding or require an external force to radially expand stent 10. In some embodiments, filaments may be used to fabricate stent 10, and the filaments may be composite filaments, e.g., having an outer shell made from Nitinol and a platinum core. It is further contemplated that the filaments of stent 10 can be formed from polymers, including, but not limited to, polyethylene terephthalate (PET).

[0032] In some cases, in the radially expanded configuration, the stent 10 may include a first end region 28 proximate the first end 14 and a second end region 30 proximate the second end 16. In some embodiments, the first end region 28 and the second end region 30 may include shoulders or enlarged regions, such as a plurality of flanges 32, 34, positioned adjacent the first end 14 and the second end 16 of the stent 10. The flanges 32, 34 may be configured to engage an interior portion of the wall of a body cavity or lumen. For example, the first flange 32 may be positioned relative to the interior of a first body lumen, and the second flange 34 may be positioned relative to the interior of a second body lumen different from the first body lumen. Thus, the stent 10 may be positioned to cross between two separate anatomical structures. For example, referring to FIG. 3 , the stent 10 is positioned to extend between the gallbladder 90 and the duodenum 92. The first flange 32 is positioned within the gallbladder 90, and the second flange 34 is positioned within the duodenum 92. The intermediate region or body 18 of the stent 10 extending between the first flange 32 and the second flange 34 may extend through a wall 94 of the gallbladder 90 and a wall 96 of the duodenum 92. In some cases, the first flange 32 may contact the interior of the wall 94 of the gallbladder 90 and / or the second flange 34 may contact the interior of the wall 96 of the duodenum, although this is not required.

[0033] In some embodiments, the flanges 32, 34 have a larger diameter than the midregion or body 18 of the stent 10 located between the end regions 28, 30, thereby preventing or helping to prevent migration of the stent 10 once the stent 10 is deployed in or across a body lumen. It is contemplated that the transition from the cross-sectional area of ​​the midregion or body 18 to the retention features or flanges 32, 34 may occur in a gradual, sloped, or abrupt stepwise manner, as desired. In some cases, the flanges 32, 34 may have a shape approximating a curved hemisphere, gradually increasing in cross-sectional dimension in one direction and then gradually decreasing in cross-sectional dimension, such that the first and / or second ends 14, 16 have similar cross-sectional dimensions as the midregion or body 18. However, this is not required. Other shapes and / or configurations may be used as desired.

[0034] In some embodiments, the first flange 32 may have a first outer diameter, and the second flange 34 may have a second outer diameter. The outer diameter of the first flange 32 and / or the second flange 34 may be larger than the outer diameter of the intermediate region or body 18. In some instances, the first outer diameter and the second outer diameter may be substantially the same, while in other instances, the first outer diameter and the second outer diameter may be different. In some embodiments, the stent 10 may include only one flange 32, 34, or the stent 10 may not include a flange, if desired. For example, the first end region 28 may include the flange 32, and the second end region 30 may have an outer diameter similar to the outer diameter of the intermediate region or body 18. It is further contemplated that the second end region 30 may include the flange 34, and the first end region 28 may have an outer diameter similar to the outer diameter of the intermediate region or body 18. In some embodiments, the stent 10 may have a uniform outer diameter from the first end 14 to the second end 16. In some embodiments, the outer diameter of the intermediate region or body 18 may be in the range of 15 to 25 millimeters. The outer diameter of the flanges 32, 34 may be in the range of 20 to 30 millimeters. It is contemplated that the outer diameter of the stent 10 may be varied to suit a desired application.

[0035] As can be seen more clearly in FIG. 4 , in some embodiments, the outer surface of the stent 10 can include a coating 36 configured to promote tissue ingrowth after treatment and / or deployment of the stent 10. The coating 36 can be deposited on at least a portion of the outer coating 26, or on at least a portion of the inner coating 24 in instances where the outer coating 26 is not present. In the absence of the inner coating 24 and / or outer coating 26, the coating 36 can be deposited on the struts 22 and / or within at least a portion of the plurality of openings 23. In some cases, the coating 36 can be configured to induce new tissue ingrowth around and through the stent 10. Referring briefly to the example of FIG. 3 , the coating 36 can be configured to induce tissue growth such that the openings formed through the walls 94, 96 of the cavities 90, 92 described above become natural parts of the body. For example, in this situation, the orifices described above would remain open to permanently drain the gallbladder regardless of whether the stent 10 is in place. Stent 10 may be deployed at the desired treatment location and left in place until tissue ingrowth forms a natural orifice or pathway between the two non-adherent tissues / structures. It is contemplated that the ingrowth of new, healthy tissue around stent 10 will reduce the likelihood of stent migration, as healthy tissue will grip stent 10 and the body's natural peristalsis is believed to be insufficient to dislodge stent 10 from the ingrowth tissue. However, in some cases, stent 10 may be removed through endoscopic means after several weeks, if necessary, leaving a newly formed tissue conduit spanning the two non-adherent tissues / structures, forming an anastomosis between them.

[0036] Returning to FIG. 4 , the coating 36 may include a first or inner microporous layer 38 and a second or outer macroporous layer 40 positioned over the inner microporous layer 38. Although not explicitly shown, in some cases, a second microporous layer may be deposited over the macroporous layer 40. Generally, the inner microporous layer 38 can limit stent migration by improving cellular adhesion to the surface of the stent 10, while the macroporous layer 40 can promote anastomosis formation by encouraging vascular structures to grow along the surface of the stent 10. For example, the inner microporous layer 38 can promote cellular attachment, while the outer macroporous layer 40 can promote tissue ingrowth. It is further contemplated that the coating 36 may inhibit or limit a foreign body response. The inclusion of both the inner microporous layer 38 and the macroporous layer 40 can promote anastomosis growth from the natural tissue between the gallbladder 90 and the stomach / duodenum 92 (or two other non-adherent structures / tissues) without the stent 10 migrating from its original position. In some embodiments, the inner microporous layer 38 and / or the outer macroporous layer 40 will be absorbed into the body tissue over time as new tissue ingrowth occurs. As tissue from the two non-adhered structures grows, the tissue from each of the non-adhered structures will grow together or connect to form a tissue conduit between the non-adhered structures. This may allow the formed tissue anastomosis to remain in the body even after the stent 10 (with its inner and outer layers 24, 26) is removed.

[0037] The coating 36 may be formed by any desired process. For example, the coating 36 may be formed by a combination of spray coating and direct ink writing (DIW). For example, the inner microporous layer 38 may be created by spraying a sprayable ink onto the stent 10. As used herein, "ink" may refer to a liquid used to print the inner microporous layer 38 on the stent 10. The ink may be sprayed in liquid form, and any solvent may be evaporated to leave a solid having a micropatterned texture. In some cases, the inner microporous layer 38 may require curing to solidify the coating. The inner microporous layer 38 may have a plurality of interconnected pores in the 2 micrometer (μm) or less range, or in the range of about 0.05 μm to about 2 μm. The inner microporous layer 38 may have a thickness in the micrometer range. For example, the inner microporous layer 38 may have a thickness in the range of about 10 μm to about 80 μm, about 20 μm to about 60 μm, or about 40 μm. In some cases, the sprayable ink may be a sprayable silicone ink. It is contemplated that the sprayable ink may include an additive configured to increase porosity by removing the additive after the sprayable ink is cured.

[0038] The macroporous layer 40 may be formed by extruding a high viscosity material onto the stent 10 using, for example, 3D printing, thereby forming a columnar structure extending above the microporous layer 38. In some embodiments, the columnar structure may include a plurality of columns extending from the microporous layer 38 with spaces between them. In some embodiments, the columnar structure forming the macroporous layer may be considered a rope coil layer. A rope coil layer derives its name from the material's tendency to coil like a rope when ejected from an extruder. It is contemplated that the material may have a viscosity that allows the material to retain the cross-sectional dimensions of the extruder when applied to the stent 10. For example, the material may be resistant to flow during and / or after extrusion. It is contemplated that the material may be any biocompatible or bioabsorbable material, as desired. The thickness of the macroporous layer 40 may range from at least 1 micron (μm) to at least 1 millimeter (mm) (measured in a direction extending outward from the outer surface of the microporous layer 38), such as from about 1.5 μm to about 850 μm, from about 5 μm to about 10 μm, from about 50 μm to about 250 μm, from about 350 μm to about 750 μm, from about 450 μm to about 600 μm, from about 650 μm to about 950 μm, or from about 300 μm to about 550 μm. The pattern of the macroporous layer 40 will be determined at least in part by the speed of movement of the stent 10 (e.g., axial movement relative to the extruder), the flow rate of the material from the extruder, the diameter of the extruder, and / or the distance between the extruder and the stent 10. For example, when stent 10 moves relative to the extruder, the material may form multiple loops, while when stent 10 is stationary, the multiple loops may coil together to form vertically rising coils (e.g., similar to a spring).

[0039] 5 shows a schematic diagram of an exemplary pattern 100 of the macroporous layer 40 as the stent 10 moves relative to the extruder. The macroporous layer 40 may be formed as one or more rows 112 of a plurality of loops 102a, 102b, 102c (collectively 102). Each loop 102 may include a loop portion 104a, 104b, 104c (collectively 104) and an overlapping base portion 106a, 106b, 106c (collectively 106). The overlapping base portions 106a, 106b, 106c are understood to be portions of the plurality of loops 102 where one segment of the filament overlaps or crosses over a second segment of the filament, forming the intervening loop portions 104a, 104b, 104c. In the illustrated pattern 100, gaps 108a, 108b exist between adjacent loop portions 104, such that the trailing loops 102b, 102c do not contact the leading loops 102a, 102b. However, this is not required. The pattern 100 may be formed such that adjacent loops 102 overlap one another. The degree of overlap may range from one loop 102 formed on top of the other to adjacent loop portions 104 just touching one another. For example, the distance 110a, 110b (collectively 110) between similar locations on adjacent loops 102 may be zero or substantially zero, resulting in the loops 102 being vertically stacked on top of one another. In other cases, the distance 110 between similar locations on adjacent loops 102 may be less than the width of the loops 102, such that the trailing loop is partially formed on top of the leading loop 102. It is further contemplated that laterally adjacent loops 102 may not be connected to one another. For example, in some cases, the plurality of loops 102 may form a first vertically extending column of stacked loops 102, as described in more detail herein.

[0040] FIG. 6 shows an enlarged plan view of a portion of the macro-porous layer 40. The macro-porous layer 40 may include multiple layers 114a, 114b (collectively 114), each having multiple rows 112a-h formed from multiple loops 102a-f, although not all loops are formally identified with reference numerals for the sake of brevity and ease of understanding. The innermost layer 114a may be applied to the outer surface of the stent 10 (e.g., over the inner micro-porous layer 38), and then the outer layer 114b may be disposed over the inner layer 114a. In some cases, the inner micro-porous layer 38 and the macro-porous layer 40 may be applied and adhered directly to the outer surface (e.g., the outer layer 26, if present), while in other cases, the inner micro-porous layer 38 and the macro-porous layer 40 may be applied to a sleeve positioned on, but not necessarily connected to, the outer surface of the stent 10. Although FIG. 6 shows two layers 114, it is contemplated that the macroporous layer 40 may include fewer or more than two layers, as desired.

[0041] The first layer 114a may be formed by rotating the stent 10 about its longitudinal axis (relative to the extruder) as the material is extruded to form circumferentially extending rows 112a. The stent 10 can then be displaced axially to deposit another circumferentially extending row 112b. This can be repeated for as many rows as desired. In another embodiment, the first layer 114a may be formed by displacing the stent 10 axially (relative to the extruder) as the material is extruded to form longitudinally extending rows. The stent 10 can then be rotated about its longitudinal axis to deposit another longitudinally extending row. This can be repeated for as many rows as desired.

[0042] Once the first layer 114a is completed, one or more additional layers 114b can be deposited on top of the preceding layer. In the embodiment shown in FIG. 6, the second layer 114b is shown with columns 112e-h vertically and horizontally offset from columns 112a-d of the first layer 114a. However, this is not required. In some cases, the second layer 114b can be applied such that columns 112e-h (and corresponding loops 102d-f) are aligned with or stacked on top of columns 112a-d (and corresponding loops 102a-c) of the preceding layer 114a. In other examples, the second layer 114b can be applied at an angle relative to the first layer 114a. For example, columns 112e-h of the second layer 114b can be non-parallel to columns 112a-d of the first layer 114a. In other embodiments, columns 112e-h in second layer 114b may be vertically or horizontally offset from columns 112a-d in first layer 114a.

[0043] The inner micro-porous layer 38 and / or macro-porous layer 40 may be deposited over the entire outer surface of the stent 10, or less than the entire outer surface, as desired. For example, in some cases, the inner micro-porous layer 38 and / or macro-porous layer 40 may be deposited on the mid-region or body 18 of the stent 10 extending between the flanges 32, 34, as shown in FIG. 2 , although the flanges 32, 34 may lack the inner micro-porous layer 38 and / or macro-porous layer 40. However, it should be understood that the inner micro-porous layer 38 and / or macro-porous layer 40 may be deposited in any desired configuration, including a uniform pattern, an offset arrangement, less than the entire circumference of the stent 10, less than the entire length of the stent 10, combinations thereof, etc. For example, the inner micro-porous layer 38 and / or macro-porous layer 40 may be selectively deposited on the stent 10 to control the anchoring characteristics of the stent 10 at the target treatment site.

[0044] In some embodiments, the surface of the stent 10 may be mapped or scanned prior to depositing the inner microporous layer 38 and / or macroporous layer 40. This would allow the extruder control panel to understand the surface topography and apply the coating 36 to a desired height. For example, the extruder may be configured to apply the coating 36 in a manner that allows the outer surface to have uniform outer dimensions despite variations in the cross-sectional dimensions of the substrate (e.g., the scaffolding structure of the stent 10).

[0045] FIG. 7A is a partial cross-sectional view of a stent 10 having an alternative macroporous layer 40′ with an alternative loop arrangement. The coating 36 can include a first or inner microporous layer 38, a second or intermediate macroporous layer 40′ positioned on or outside the inner microporous layer 38, and a third or outer microporous layer 42 positioned on or outside the macroporous layer 40′. The macroporous layer 40′ can include a columnar structure, such as a plurality of posts 44. Each post 44 can be formed from a plurality of coiled loops 46 stacked one on top of the other like the coils of a spring or rope and extending radially outward from the microporous layer 38. While the plurality of posts 44 are shown each having five loops 46, each post 44 can have fewer or more than five loops 46 as needed to achieve a desired height. It is further contemplated that the plurality of posts 44 can have a varying number of loops 46 to form multiple posts 44 having different heights. The multiple posts 44 may be axially and / or circumferentially spaced from one another in any desired arrangement. In some embodiments, two or more posts 44 may contact one another.

[0046] The outer microporous layer 42 may be created by spraying a sprayable ink onto the stent 10 after the macroporous layer 40' has been deposited. The ink can be sprayed in liquid form, and any solvent can be evaporated to leave a solid having a micropatterned texture. In some cases, the outer microporous layer 42 will need to be cured to solidify the coating. The outer microporous layer 42 may have a plurality of interconnected pores in the range of 2 micrometers (μm) or less, or in the range of about 0.05 μm to about 2 μm. The outer microporous layer 42 may have a thickness in the micrometer range. For example, the outer microporous layer 42 may have a thickness in the range of about 10 μm to about 80 μm, about 20 μm to about 60 μm, or about 40 μm. In some cases, the sprayable ink may be a sprayable silicone ink. It is contemplated that the sprayable ink may include an additive configured to increase porosity by removing the additive after the sprayable ink is cured.

[0047] In some embodiments, the outer microporous layer 42 may be formulated to provide additional nutrients to further promote cellular ingrowth. For example, the outer microporous layer 42 may contain or be derived from a nutrient solution, such as, but not limited to, a nutrient agar or nutrient broth. Alternatively or additionally, a coating containing or derived from a nutrient solution may be sprayed or otherwise deposited over the outer microporous layer 42 (or over the macroporous layer 40, 40′ in the absence of the outer microporous layer 42). Nutrient solutions may be commonly used in tissue culture to promote tissue growth in micropropagation cultures and would similarly be used to promote tissue growth in the body after treatment. This added spray / coating can be allowed to remain for a predetermined length of time, such as several days or weeks, after which point the stent 10 can be removed, if applicable, and the body will naturally form an anastomosis with natural tissue growing between and connecting the gallbladder and the duodenum or stomach (or between two other non-adherent tissues / structures).

[0048] The inner microporous layer 38, the macroporous layer 40′, and / or the outer microporous layer 42 may be deposited over the entire or less than the entire outer surface of the stent 10, as desired. For example, in some cases the inner microporous layer 38, the macroporous layer 40′, and / or the outer microporous layer 42 may be deposited on the middle region or body 18 of the stent 10 extending between the flanges 32, 34, while the flanges 32, 34 may lack the inner microporous layer 38, the macroporous layer 40′, and / or the outer microporous layer 42. However, it should be understood that the inner microporous layer 38, the outer microporous layer 42, and / or the macroporous layer 40 may be deposited in any desired configuration, including a uniform pattern, an offset arrangement, less than the entire circumference of the stent 10, less than the entire length of the stent 10, combinations thereof, etc.

[0049] 7A, the outer microporous layer 42 may extend over the columnar structure formed by the plurality of posts 44 and may span the spaces between adjacent posts 44. By spanning the spaces between adjacent posts 44, a void 45 may be defined between the outer surface of the inner microporous layer 38 and the outer microporous layer 42 between the adjacent posts 44. The void 45 may allow tissue ingrowth into the void 45 after deployment, which may facilitate the formation of a tissue conduit to form an anastomosis between two anatomical structures.

[0050] In an alternative configuration shown in FIG. 7B, the outer microporous layer 42 would extend over the columnar structure formed by the pillars 44 and would extend radially inward in the spaces between adjacent pillars 44 to contact the outer surface of the inner microporous layer 38 between adjacent pillars 44.

[0051] FIG. 8A shows another configuration of a macro-porous layer 40″ extending over the inner micro-porous layer 38. Note that the outer micro-porous layer 42 is omitted from FIG. 8A for clarity, but can be provided over the macro-porous layer 40″ as shown in FIG. 7A or 7B. The macro-porous layer 40″ can include a columnar structure formed from multiple posts, such as elongated baffles or dividers 47. The baffles or dividers 47 may extend longitudinally, circumferentially, sinusoidally, or at another origin or arrangement. The baffles or dividers 47 may extend between the outer surface of the inner micro-porous layer 38 and the inner surface of the outer micro-porous layer 42, providing a gap therebetween for tissue ingrowth. The baffles or dividers 47 may be formed, such as by multiple layers of a 3D printing process, similar to the posts 44 described above.

[0052] FIG. 8B shows another configuration of a macro-porous layer 40'" extending over the inner micro-porous layer 38. Note that the outer micro-porous layer 42 is omitted from FIG. 8B for clarity, but may be provided over the macro-porous layer 40'" as shown in FIG. 7A or 7B. The macro-porous layer 40'" may include a columnar structure formed from a plurality of columns, such as walls or struts 49. The walls or struts 49 may extend at any desired origin or arrangement. The walls or struts 49 may extend between the outer surface of the inner micro-porous layer 38 and the inner surface of the outer micro-porous layer 42, providing a space therebetween for tissue ingrowth.

[0053] FIG. 9A shows a partial schematic cross-sectional view of an exemplary stent 10 illustrating another exemplary arrangement of pillar-like structures including a plurality of pillars 52a-m (collectively 52) forming another exemplary macroporous layer 40''''. The pillars 52 may be similar in form and function to the pillars 44 described herein. In the illustrated embodiment, the plurality of pillars 52 may be deposited such that tissue growth from two different non-adherent tissues / structures is directed toward one another (e.g., toward the central pillar 52g). For example, the macroporous layer 40'''' may include a first group 48 of pillars 52a-f extending from a location adjacent the first flange 32 toward the midpoint of the plurality of pillars 52 (e.g., toward the middle pillar 52g) at a medial point of the body 18 of the stent 10, and a second group 50 of pillars 52h-m extending from a location adjacent the second flange 34 toward the midpoint of the plurality of pillars 52 (e.g., toward the centrally located pillar 52g) at a medial point of the body 18 of the stent 10. While intermediate post 52g is shown as being centrally located along the length of stent 10, this is not required. In some cases, the midpoint of the plurality of posts 52 may not correspond to the midpoint of stent 10, but may be at another location closer to the center of body 18 of stent 10. First group 48 of posts 52a-f may be oriented such that the longitudinal axes of posts 52a-f extend at a non-orthogonal angle (e.g., an oblique angle) relative to the longitudinal axis of stent 10, such that the free end of each of posts 52a-f (e.g., radially spaced from stent 10) points toward centrally located post 52g. Similarly, second group 50 of posts 52h-m may also be oriented such that the longitudinal axes of posts 52h-m extend at a non-orthogonal angle (e.g., an oblique angle) relative to the longitudinal axis of stent 10, such that the free end of each of posts 52h-m (e.g., radially spaced from stent 10) points toward centrally located post 52g. Note that the outer microporous layer 42 is omitted from FIG. 9A for clarity, but may be provided on the macroporous layer 40'''' as shown in FIG. 7A or 7B.

[0054] FIG. 9B shows an enlarged view of a portion of stent 10 indicated by the dashed line in FIG. 9A. A middle or centrally located post 52g can have a longitudinal axis 56 that forms a substantially orthogonal angle 58 with respect to the longitudinal axis 54 of stent 10. A first group 48 of posts 52a-f can extend at an oblique angle between 0° and 90° with respect to the longitudinal axis. The angle of the first group 48 of posts 52a-f can be uniform along the length of stent 10, or the angle of the first group 48 of posts 52a-f can increase gradually toward the centrally located post 52g. For example, a first post 52f adjacent to the centrally located post 52g can have a longitudinal axis 60 that extends at a first non-orthogonal angle (e.g., acute angle) 62 with respect to the longitudinal axis 54 of stent 10, and a subsequent second post 52e can have a longitudinal axis 64 that also extends at a second non-orthogonal angle (e.g., acute angle) 66 with respect to the longitudinal axis 54. The first acute angle 62 may be less than 90° but greater than the second acute angle. Moving from the centrally located post 52g toward the first flange 32, each post 52a-f in the first group 48 may have an acute angle that is less than the acute angle of its immediate neighbors 52a-f. However, this is not required. In some cases, each of the posts 52a-f in the first group 48 may have the same non-orthogonal angle (e.g., acute angle). In still other embodiments, the angles of the posts 52a-f in the first group 48 may vary unevenly or non-uniformly.

[0055] The second group 50 of pillars 52h-m may extend at an oblique angle between 90° and 180° with respect to the longitudinal axis. The angle of the second group 50 of pillars 52h-m may be uniform along the length of the stent 10, or the angle of the second group 50 of pillars 52h-m may decrease gradually toward the centrally located pillar 52g. For example, a first pillar 52h adjacent to the centrally located pillar 52g may have a longitudinal axis 68 that extends at a third non-orthogonal (e.g., obtuse) angle 70 with respect to the longitudinal axis 54 of the stent 10, and the next second pillar 52i may also have a longitudinal axis 72 that extends at a fourth non-orthogonal (e.g., obtuse) angle 74 with respect to the longitudinal axis 54. The third obtuse angle 70 may be greater than 90° but less than the fourth obtuse angle. Moving from the centrally located post 52g toward the second flange 34, each post 52h-m in the second group 50 may have a larger obtuse angle than its immediately adjacent post 52h-m. However, this is not required. In some cases, each of the posts 52h-m in the second group 50 may have the same non-orthogonal angle (e.g., obtuse angle). In still other embodiments, the angles of the posts 52h-m in the second group 50 may vary unevenly or non-uniformly.

[0056] FIG. 10 depicts a partial schematic cross-sectional view of an exemplary stent 10 illustrating another exemplary arrangement of a columnar structure formed of multiple pillars 80a-k (collectively 80) forming another exemplary macroporous layer 40'''''. The pillars 80 may be similar in form and function to the pillars 44 described herein. The pillars 80 may extend radially from the outer surface of the inner microporous layer 38. While the multiple pillars 80 are shown extending generally perpendicular to the longitudinal axis of the stent 10, it is contemplated that one or more of the multiple pillars 80 may extend at a non-orthogonal angle if desired. In the illustrated embodiment, the multiple pillars 80 may be deposited such that tissue growth from two different non-adherent tissues / structures is directed toward one another (e.g., toward the central pillar 80f). For example, the pillars 80 may have varying longitudinal and / or circumferential spacing along the length and / or circumference of the stent 10. While the central pillar 80f is shown as being centrally located along the length of the stent 10, this is not required. In some cases, the midpoints of the posts 80 may not correspond to the midpoint of the stent 10 .

[0057] In some cases, the longitudinal and / or circumferential spacing between adjacent posts 80 may decrease toward the centrally located post 80f, resulting in a higher density of posts 80 adjacent to the centrally located post 80f than near either the first flange 32 or the second flange 34. For example, there may be a first distance 82 between the distal-most post 80k (closer to the distal end 16) and the post 80j proximally adjacent to post 80. There may be a second distance 84 between the second-most post 80j from the distal end and the post 80i proximally adjacent to post 80j. The second distance 84 may be less than the first distance 82. There may be a third distance 86 between the centrally located post 80f and the post 80g distally adjacent to post 80f. The third distance 86 may be less than either the first or second distances 82, 84. The pillars 80a-80e proximal to the centrally located pillar 80f (e.g., closer to the proximal end 14) may have similar spacing, with the distance between adjacent pillars 80 decreasing toward the centrally located pillar 80f. While the spacing between the pillars 80 is shown in terms of longitudinal spacing, it is contemplated that the circumferential spacing may also decrease toward the centrally located pillar 80f, but this is not required. In other examples, the longitudinal spacing may remain constant, but the circumferential spacing decreases toward the centrally located pillar 80f. In still other embodiments, the longitudinal and circumferential spacing of the pillars 80 may increase toward the centrally located pillar 80f, or the pillars may be unevenly or unevenly spaced.

[0058] After creating an anastomosis between two separate anatomical structures by placing the stent 10, tissue can grow into the void space along the macro-porous layers 40, 40', 40'', 40'', 40'''', 40'''' from one or both anatomical structures (e.g., the gallbladder and gastrointestinal (GI) tract), thereby forming a tissue conduit from the native tissue around the stent 10. For example, as described above, the inner micro-porous layer 38 can promote cellular attachment, and the outer macro-porous layer 40 can promote tissue ingrowth. It is further contemplated that the coating 36 can inhibit or limit a foreign body reaction. The inclusion of both the inner micro-porous layer 38 and the macro-porous layer 40 can promote the growth of an anastomosis from the native tissue between the gallbladder 90 and the stomach / duodenum 92 (or two other non-adherent structures / tissues) without the stent 10 migrating from its position. In some embodiments, the inner micro-porous layer 38 and / or the outer macro-porous layer 40 will be absorbed into the body tissue over time as new tissue ingrowth occurs. As tissue from the two non-adherent structures grows, the tissue from each of the non-adherent structures will grow together or connect to form a tissue conduit between the non-adherent structures. In some embodiments, once sufficient native tissue has formed along the body 18 of the stent 10, the stent 10 may be removed, leaving a native tissue conduit for fluid drainage between multiple anatomical structures (e.g., the gallbladder and the gastrointestinal (GI) tract) as an anastomosis.

[0059] In some embodiments, the coating 36 may comprise a polymer matrix. FIG. 11A is a schematic top view of an exemplary polymer matrix 200. The polymer matrix 200 may comprise a plurality of fibers 202 defining a plurality of pores 204 (e.g., interstices). The plurality of fibers 202 may be disposed over the plurality of struts 22 and the plurality of openings 23 of the tubular member 12 (e.g., providing a porous matrix on the tubular member 12). Each fiber of the plurality of fibers 202 may have a diameter ranging from about 100 nanometers (nm) to about 900 nm, e.g., from about 300 nm to about 700 nm, from about 230 nm to about 550 nm, or from about 450 nm to about 650 nm. Each fiber 202 may have the same diameter, or the plurality of fibers 202 may comprise fibers of different sizes. It should be understood that the diameter of the fibers 202 may at least partially determine the size of the pores 204 defined between adjacent fibers 202. It is further contemplated that the diameter of the fibers 202 may at least partially determine the amount of tissue ingrowth that may occur through the polymer matrix 200. For example, fibers 202 having a diameter in the range of greater than about 500 nanometers (nm) may promote tissue ingrowth, while diameters less than 500 nm may render the polymer matrix 200 a barrier to tissue ingrowth. The thickness of the polymer matrix 200 may range from at least 1 micron (μm) to at least 1 millimeter (mm), such as from about 1.5 μm to about 850 μm, from about 5 μm to about 10 μm, from about 50 μm to about 250 μm, from about 350 μm to about 750 μm, from about 450 μm to about 600 μm, from about 650 μm to about 950 μm, or from about 300 μm to about 550 μm. It is contemplated that the thickness of the polymer matrix 200 may at least partially determine the ease with which the stent 10 can be removed. For example, a thinner polymer matrix 200 will allow less tissue ingrowth than a thicker polymer matrix 200. Less tissue ingrowth will increase the removability of the stent 10.Some exemplary polymer matrices can be found in commonly assigned U.S. Patent Application Publication No. 2022 / 0296396, published September 22, 2022, entitled MEDICAL IMPLANTABLE DEVICES AND METHODS OF USING THE SAME, the disclosure of which is incorporated herein by reference.

[0060] The polymer matrix 200 may be porous and thus permit the passage of one or more materials through the polymer matrix 200. For example, as described in further detail herein, the polymer matrix 200 may permit tissue growth between the plurality of fibers 202 and through the plurality of pores 204. The dimensions (e.g., thickness, diameter, etc.) of the plurality of fibers 202 and / or the dimensions of the plurality of pores 204 may at least partially determine the rate of tissue growth through the polymer matrix 200. In some embodiments, sintering the plurality of fibers 202 may strengthen the material composition of the plurality of fibers 202 and reduce the brittleness of the polymer matrix 200. According to some embodiments herein, the porosity of the polymer matrix 200 may remain substantially consistent when sintering the plurality of fibers 202. Further, for example, the porosity of the polymer matrix 200 may be fine-tuned to permit appropriate cell growth infiltration and degradation between the plurality of fibers 202 and through the plurality of pores 204.

[0061] In some examples, the stent 10 may include two or more layers of polymer matrix 200. It is contemplated that the layers may be extremely thin layers stacked one on top of the other to achieve a desired thickness. In some examples, the layers may have similar properties. For example, each layer may have similar porosity and / or include fibers of similar dimensions. However, this is not required. In some cases, different layers may provide different properties. FIG. 11B is a schematic top view of another exemplary polymer matrix 210. The polymer matrix 210 may include a plurality of fibers 212 defining a plurality of pores 214 (e.g., interstices). The plurality of fibers 212 may be similar in form and function to the plurality of fibers 202 described herein. It is contemplated that the density of the plurality of fibers 212 in the polymer matrix 210 may be greater than the density of the plurality of fibers 202 in the polymer matrix 200 of FIG. 11A. The density of the plurality of fibers 212 in the polymer matrix 210 of FIG. 11B may arrest tissue ingrowth. 11B may be positioned between the stent 10 and the polymer matrix 200 of FIG. 11A. It is contemplated that positioning a denser polymer matrix 210 between a less dense polymer matrix 200 (configured to promote tissue ingrowth) and the tubular member 12 can allow tissue ingrowth to a particular depth (e.g., the thickness of the less dense polymer matrix 200) while preventing tissue ingrowth from reaching the struts 22 of the stent 10. In some cases, the denser polymer matrix 210 can provide a lubricious, insulating layer between the target tissue and the struts 22 of the stent 10.

[0062] The polymer matrix 200 may be formed on the tubular member 12 by any suitable technique, including, for example, electrospinning. For example, the polymer matrix 200 may be formed by electrospinning a polymer material onto the tubular member 12. Exemplary polymer materials include, but are not limited to, thermoplastic polymers, including fluoropolymers, that can be electrospun while in liquid solution form. The material may be delivered with high electrical force so that it deposits over the exterior of the tubular member 12 in a randomized, asymmetric, and / or irregular pattern. The solvent in the solution evaporates, forming polymer chains that may become, for example, mechanically entangled. The resulting structure may include a plurality of fibers 202 deposited on the tubular member 12. In some embodiments, the polymer matrix 200 may include polyvinylidene fluoride, polyvinylidene difluoride (PVDF), and / or hexafluoropropylene (HFP).

[0063] 11A , the plurality of fibers 202 may be intertwined with one another on the plurality of struts 22. It should be understood that the plurality of fibers 202 may further be intertwined with the exterior surface of the tubular member 12, such as, without limitation, the inner coating 24 and / or the outer coating 26 (if provided), to secure the polymer matrix 200 to the tubular member 12. The plurality of fibers 202 may be intermingled with the material of the outer layer 26. The outer layer 26 may include a polymer such as, for example, silicone. Thus, during the electrospinning process to produce the polymer matrix 200 on the tubular member 12, the material (e.g., a fluoropolymer) electrospun onto the tubular member 12 will mechanically entangle with the outer layer 26.

[0064] The outer layer 26 may be positioned between at least a portion of the tubular member 12 and the polymer matrix 200. A suitable polymer material, such as silicone, of the outer layer 26 may be disposed within at least a portion of the openings 23 between the struts 22, and the fibers 202 may be deposited on the struts 22 and / or the openings 23. To minimize restricting the flexibility of the tubular member 12, the fibers 202 may be concentrated on the struts 22 during the electrospinning process of the polymer matrix 200. Furthermore, the fibers 202 may be selectively directed across the struts 22 during the electrospinning process to preserve the contours of the openings 23 defined between the struts 22. Once the polymer matrix 200 is formed along the exterior of the tubular member 12, the polymer matrix 200 may provide and maintain a barrier around the lumen of the tubular member 12. As described in detail herein, the polymer matrix 200 can provide an anchoring mechanism for securing the stent 10 at a targeted treatment site within a subject. Additionally, the polymer matrix 200 can promote tissue ingrowth, thereby facilitating the formation of an anastomosis between two non-adherent tissues / structures.

[0065] The stent 10 may further include an optional bioadhesive coating 206 disposed on and at least partially covering the polymer matrix 200. The bioadhesive coating 206 may be chemically bonded to the polymer matrix 200. Thus, the polymer matrix 200 may be disposed between the bioadhesive coating 206 and the tubular member 12, such that the bioadhesive coating 206 is separated from the tubular member 12 by the polymer matrix 200. The bioadhesive coating 206 may include a biodegradable material such that the bioadhesive coating 206 is resorbed or otherwise degraded after a period of time. The bioadhesive coating 206 may maintain contact with the target treatment site (e.g., tissue) for a desired period of time, which may depend on the chemical properties and / or thickness of the bioadhesive coating 206. For example, the bioadhesive coating 206 may maintain contact with the target treatment site for about 24 hours to about 6 months, e.g., about 3 days to about 1 week, about 1 week to about 6 weeks, about 1 month to about 3 months, or about 2 months to about 5 months. The degradation time will be controlled by various factors, including, for example, the nature of the biodegradable material and / or the amount (e.g., thickness) of the bioadhesive coating 206 on the polymeric matrix 200. The thickness of the bioadhesive coating 206 on the polymeric matrix 200 can range from at least about 1 μm to at least 1 mm, and can range from about 1.5 μm to about 850 μm, about 5 μm to about 10 μm, about 50 μm to about 250 μm, about 350 μm to about 750 μm, about 450 μm to about 600 μm, about 650 μm to about 950 μm, or about 300 μm to about 550 μm. Additionally, the bioadhesive coating 206 can be chemically modified on the exterior surface of the polymeric matrix 200.

[0066] Exemplary materials suitable for the bioadhesive coating 206 include, but are not limited to, polysaccharides such as chitosan. The polysaccharide may be crosslinked with a linker molecule. Such linker molecules include, for example, polyethylene glycol (PEG). In some cases, 1-ethyl-3-(-3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) may be added to bond the chitosan and PEG. PEG can provide a hydrophilic scaffold along the polymer matrix 200 and serve as an anchor for attaching the bioadhesive coating 206 to the polymer matrix 200. The hydrophilic properties of PEG can provide adhesive capabilities for securing the bioadhesive coating 206 to the polymer matrix 200. Other suitable materials for the bioadhesive coating 206 may include, but are not limited to, polymers such as, for example, chitosan optionally modified with thiol groups, PEG modified with thiol groups, and oxidized cellulose. The bioadhesive coating 206 may have hemostatic properties to stimulate a healing response from the target treatment site (e.g., tissue) upon contact with the target treatment site. Stated another way, the bioadhesive coating 206 can treat injuries at the target treatment site, such as wounds, hemorrhage, damaged tissue, bleeding, etc. The bioadhesive coating 206 can function as a wound dressing to control excessive bleeding and / or promote rapid healing. Additionally, the bioadhesive coating 206 may have adhesive properties that can secure the tubular member 12 to the target treatment site. For example, in some cases, the bioadhesive coating 206 may have a positive charge that is complementary to the negative charge of the body's mucosal layer. In some cases, the bioadhesive coating 206 may be dried, which will further increase the attractive force between the bioadhesive coating 206 and the hydrated mucosal layer.

[0067] As described above, the bioadhesive coating 206 can be chemically bonded to the polymer matrix 200, including via linker molecules. Thus, the linker molecules (e.g., PEG) can crosslink with the plurality of fibers 202, facilitating a connection between the bioadhesive coating 206 and the polymer matrix 200. In some embodiments, the linker molecules can become entangled with the polymer chains of the polymer matrix 200 as the plurality of fibers 202 are formed on the tubular member 12. In some embodiments, the bioadhesive coating 206 can be prepared using a plasma to crosslink the polysaccharide and the linker molecules. The bioadhesive coating 206 can provide a temporary fixation mechanism for securing the stent 10 at a targeted treatment site within a subject.

[0068] According to some aspects of the present disclosure, the plurality of fibers 202 may be selectively deposited on the tubular member 12 to control the anchoring characteristics of the stent 10 at the target treatment site and / or other properties of the stent 10. For example, the plurality of fibers 202 may be deposited along one or more regions of the tubular member 12, thereby controlling the area of ​​tissue ingrowth into the stent 10 in one or more specific regions. As described above, the bioadhesive coating 206 may adhere to a surface area of ​​the polymer matrix 200, such that the stent 10 can include the bioadhesive coating 206 along one or more regions of the tubular member 12 when the plurality of fibers 202 are selectively deposited thereon. In other examples, the deposition area and / or thickness of the polymer matrix 200 and / or the bioadhesive coating 206 may be strategically positioned to reduce bleeding and / or irritation at the implantation site. For example, in some embodiments, the first expansion region 32 and / or the second expansion region 34 may generate bleeding and / or tissue irritation at the implantation site. It is contemplated that increasing the thickness of the polymeric matrix 200 and / or bioadhesive coating 206 in the first expansion region 32 and / or second expansion region 34 can reduce friction between the first expansion region 32 and / or second expansion region 34 and tissue, thus reducing tissue irritation. It is further contemplated that the location and / or thickness of the polymeric matrix 200 and / or bioadhesive coating 206 on the tubular member 12 can be tailored for a particular deployment location.

[0069] Generally, stent 10 may be positioned at a target treatment site through the use of a medical device (e.g., an endoscope, a catheter, etc.) that is inserted through a subject's body and navigated toward the target treatment site. It should be understood that stent 10 may be used at a variety of locations (target treatment sites) within a subject's body, including, but not limited to, tissues such as the gastrointestinal tract, organs, etc. Once at the implantation location, stent 10 may be inserted through the medical device and deployed from there to the target site. In some embodiments, if so provided, bioadhesive coating 206 may provide a smooth, outer, atraumatic surface to facilitate passage of stent 10 through a subject and / or prevent injury to the target site by polymer matrix 200 and / or tubular member 12.

[0070] The stent 10 may be pressed against the target location so that the bioadhesive coating 206 contacts a tissue membrane, such as a mucosal layer. When the tubular member 12 has a flexible configuration, the stent 10 can conform to the contours of the target location. Furthermore, with the bioadhesive coating 206 positively charged and the tissue membrane, such as a mucosal layer, negatively charged, the bioadhesive coating 206 may be attracted to the mucosal layer and form chemical bonds with the tissue surface, thereby anchoring the stent 10 to the target location. The bioadhesive coating 206 may maintain the stent relative to the target location for at least a minimum period of time until the bioadhesive coating 206 is resorbed or otherwise degraded. Thus, the bioadhesive coating 206 can function as a tissue adhesion mechanism to temporarily secure the stent 10 at the target location and prevent migration of the stent 10 from the target treatment site. Furthermore, the bioadhesive coating 206 may further promote healing of the target location via the hemostatic properties of the bioadhesive coating 206 while it remains in contact with the target location.

[0071] Once the bioadhesive coating 206 adheres the stent 10 to the target location, the bioadhesive coating 206 may promote tissue growth through the polymer matrix 200 from the tissue wall. In other words, by maintaining the polymer matrix 200 in close proximity to the tissue wall, the bioadhesive coating 206 may allow tissue cells from the tissue wall to grow through the bioadhesive coating 206 and into the plurality of pores 204. The tissue cells may become entangled with the plurality of fibers 202, thereby anchoring the stent 10 to the tissue wall and preventing migration of the stent from the target treatment site. In other words, the plurality of pores 204 may serve as sites that allow tissue growth into the polymer matrix 200. The bioadhesive coating 206 may maintain the stent 10 against the tissue wall via bonding with a tissue membrane, such as a mucus layer, thereby allowing sufficient time for the tissue cells to grow through the polymer matrix 200.

[0072] Furthermore, as described above, the size of the plurality of pores 204 can at least partially control the growth rate of tissue cells through the polymer matrix 200, and the diameter of the plurality of fibers 202 can at least partially determine the size of the plurality of pores 204. Furthermore, the diameter of the plurality of fibers 202 may correspond to or correlate with the minimum force required to disengage the stent 10 from the target treatment site. Stated differently, the plurality of fibers 202 may be sized and / or shaped to provide the stent with sufficient mechanical strength to prevent migration of the stent 10 from the target treatment site. For example, the minimum withdrawal force sufficient to move the stent 10 relative to the target treatment site may be at least partially related to the size and / or shape of the plurality of fibers 202. Thus, the diameter of the plurality of fibers 202 may at least partially contribute to preventing unintended release of the stent 10 from the target tissue.

[0073] Upon degradation of the bioadhesive coating 206, the stent 10 may remain anchored to the tissue wall via engagement of the polymer matrix 200 with the target tissue (e.g., tissue ingrowth into the polymer matrix 200). Thus, despite removal of the bioadhesive coating 206 from between the polymer matrix 200 and the target tissue, the polymer matrix 200 and tubular member 12 may remain attached to the target tissue in response to tissue cell growth through the polymer matrix 200. By providing a physical barrier between the tubular member 12 and the target tissue, the polymer matrix 200 can ensure that a fluid pathway through the tubular member 12 is preserved. Furthermore, the polymer matrix 200 can facilitate removal of the stent 10 upon completion of the procedure. For example, the polymer matrix 200 can reduce the surface area of ​​the tubular member 12 that can be anchored to the target tissue, thereby allowing the stent 10 to be removed from the subject when a force is applied thereto. Furthermore, the thickness of the stent 10, including, for example, the thickness of the polymer matrix 200 and the exposed portions of the plurality of fibers 202, may facilitate removal of the stent 10 from the subject. Additionally, polymer matrix 200 can control the extent (e.g., depth) and / or degree of tissue ingrowth into the stent, providing further control for removal of stent 10 upon completion of the procedure. For example, as described above, in some cases, the depth of tissue ingrowth can be limited by providing an inner layer of polymer matrix 210.

[0074] In some embodiments, alternative materials can be used in place of the bioadhesive coating, with or without the polymer matrix 200. FIG. 12 is an enlarged cross-sectional view of a portion of an exemplary stent 10 having an alternative coating 220. While the stent 10 is shown as including an inner layer 24, an outer layer 26, and a polymer matrix 200, it is contemplated that any one, any two, or all of these layers may be omitted. In some cases, the alternative coating 220 may be a hydrogel adhesive layer. Some exemplary hydrogels may include, but are not limited to, gelatin, gelatin methacryloyl (GelMA), polyethylene glycol (PEG)-based bioadhesives, chitosan, and / or derivatives thereof. It is contemplated that the hydrogel adhesive layer may reduce foreign body reactions. In some cases, the hydrogel may be attracted to mucosal layers (or other body tissues) to facilitate attachment of the stent 10 at the target location and limit migration of the stent 10 after deployment. In some cases, the hydrogel may be configured to maintain the stent 10 in place for a desired period of time. For example, the hydrogel may be configured to maintain the stent 10 in a desired position until tissue ingrowth is provided to penetrate the struts 22 and / or polymer matrix 200 .

[0075] In another embodiment, the alternative coating 220 may be a filler hemostatic agent. Some exemplary hemostatic agents may include, but are not limited to, kaolin and sodium montmorillonite (MMT). The hemostatic agent may have some bioadhesive properties that allow the hemostatic agent to at least temporarily adhere to body tissue after deployment. In some cases, the hemostatic agent may be configured to maintain the stent 10 in a deployed position for a desired period of time. For example, the hemostatic agent may be configured to maintain the stent 10 in a desired position until tissue ingrowth is provided to penetrate the struts 22 and / or the polymer matrix 200. In some embodiments, the hemostatic agent may be provided as a coating disposed over the polymer matrix 200, as shown in FIG. 12 . In other embodiments, the hemostatic agent may be mixed into the electrospun polymer solution to directly impart hemostatic and bioadhesive properties to the polymer matrix 200. In such cases, the polymer matrix 200 may form the outermost layer of the stent 10.

[0076] FIG. 13 is a side view of another exemplary outer mesh or woven sleeve 300 for use with a stent, such as stent 10, described herein. In some cases, outer mesh or woven sleeve 300 may be formed from an elongate tubular member 302. While outer mesh or woven sleeve 300 is described as generally tubular, it is contemplated that outer mesh or woven sleeve 300 may assume any desired cross-sectional shape. For example, outer mesh or woven sleeve 300 may be shaped to cover or conform to one or more portions of stent 10, including flanges 32, 34. Outer mesh or woven sleeve 300 may be configured to extend the entire length of stent 10 or only a portion of the length of stent 10. For example, in some cases, outer mesh or woven sleeve 300 may extend along body 18 of stent 10 but not over flanges 32, 34. Thus, the entire length of outer mesh or woven sleeve 300 may be positioned between multiple flanges 32, 34. In some cases, outer mesh or woven sleeve 300 may be provided as two or more separate components, each configured to be positioned over a different portion of stent 10 with some overlap, little overlap, or no overlap between the separate components. In some cases, outer mesh or woven sleeve 300 may be fixedly coupled to stent 10. In other cases, outer mesh or woven sleeve 300 may be positioned on stent 10 but not coupled to stent 10. For example, outer mesh or woven sleeve 300 may float on the outer surface of stent 10 such that outer mesh or woven sleeve 300 can move axially and / or circumferentially relative to stent 10.

[0077] The outer mesh or woven sleeve 300 can have a first or proximal end 304, a second or distal end 306, and an intermediate region 308 disposed between the first end 304 and the second end 306. The outer mesh or woven sleeve 300 can include a lumen 310 extending from a first opening adjacent the first end 304 to a second opening adjacent the second end 306, which can allow the outer mesh or woven sleeve 300 to be positioned over the stent 10.

[0078] The outer mesh or woven sleeve 300 may be expandable from a first radially contracted configuration (not explicitly shown) to a second radially expanded configuration along with the expansion of the stent 10. In some cases, the outer mesh or woven sleeve 300 may be disposed in a configuration between the contracted and fully expanded configurations.

[0079] The outer mesh or woven sleeve 300 may have an interwoven (e.g., knitted) structure, constructed from a single filament 312 that defines open cells 314 and is interwoven with itself, or constructed from multiple filaments that are interwoven (e.g., braided) with one another. In some cases, the filament 312 may be a single filament, while in other cases, the filament 312 may be two or more filaments that are wound, braided, or woven together. While the illustrated embodiment shows a twisted knit stitch, it is contemplated that the outer mesh or woven sleeve 300 may be formed using any desired stitch. Additionally, the outer mesh or woven sleeve 300 may be formed using other techniques, including, but not limited to, weaving or winding. The stent 10 may be positioned at a target location within the body.

[0080] The plurality of open cells 314 will allow for tissue ingrowth around the filaments 312. It is contemplated that the amount of tissue ingrowth can be controlled by the tightness of the knit. For example, the outer mesh or woven sleeve 300 can be formed so that the open cells 314 are very small (e.g., adjacent portions of the filaments 314 are touching or nearly touching). In other embodiments, the outer mesh or woven sleeve 300 may be formed with a looser knit so that adjacent portions of the filaments 314 are spaced apart from one another to form larger cells 314. The larger the cells 314, the greater the tissue ingrowth may be. Sufficient tissue ingrowth into and along the outer mesh or woven sleeve 30 may form a tissue conduit connecting two separate anatomical structures and forming an anastomosis between them. In some embodiments, once the tissue ingrowth within the outer mesh or woven sleeve 300 has sufficiently formed a tissue conduit between multiple anatomical structures, the stent 10 may be removed, leaving the outer mesh or woven sleeve 300 in place at the formed anastomosis.

[0081] It is contemplated that the outer mesh or woven sleeve 300 can be made from many different materials, including, but not limited to, synthetic or bio-absorbable textile materials. Some exemplary synthetic textile materials include, but are not limited to, polyamide, polyester, polyethylene terephthalate (PTFE), expanded PTFE, polypropylene (PP), etc. Some exemplary bio-absorbable textile materials include, but are not limited to, poly(glycolic acid) (PGA), polylactic acid (PLA), poly(L-lactide) (PLLA), poly(lactic-co-glycolic acid) (PLGA), polydioxanone (PDO), etc.

[0082] It is contemplated that any of the inner layer 24 or outer layer 26, coatings / layers 36, 38, 40, 40', 40'', 40''', 40'''', 40''''', polymer matrix 200, 210, bioadhesive coating 206, alternative outer coating 220, and / or outer mesh or woven sleeve 300 may be disposed over all or selected portions of stent 10. In some cases, the location and / or thickness of inner layer 24 or outer layer 26, coating 36, 38, 40, 40', 40'', 40''', 40'''', 40'''', 40''''', polymer matrix 200, 210, bioadhesive coating 206, alternative outer coating 220, and / or outer mesh or woven sleeve 300 may be configured to reduce bleeding and / or tissue irritation. In some cases, the inner or outer layer 24, 26, coatings 36, 38, 40, 40', 40", 40'", 40"", 40'"", 40'"", polymer matrix 200, 210, bioadhesive coating 206, alternative outer coating 220, and / or outer mesh or woven sleeve 300 may be thicker in areas of the stent 10 that may be more likely to cause bleeding and / or tissue irritation upon placement in the body, including, but not limited to, flanges 32, 34. It is further contemplated that any of the inner or outer layer 24, 26, coatings 36, 38, 40, 40', 40", 40'", 40"", 40"", 40""", 40"'", polymer matrix 200, 210, bioadhesive coating 206, alternative outer coating 220, and / or outer mesh or woven sleeve 300 may be applied as multiple layers. The number of layers can be varied to achieve a desired coating thickness.

[0083] It should be understood that the present disclosure is, in many respects, merely exemplary. Changes may be made in details, particularly with respect to shape, size, and procedural arrangement, without exceeding the scope of the present disclosure. This may include, to the extent appropriate, using any of the features of one example embodiment in another embodiment. The scope of the present disclosure is naturally defined in the language in which the appended claims are expressed.

Claims

1. an elongated tubular body having a scaffold forming a plurality of cells; a coating disposed on an outer surface of the elongated tubular body; The coating a first microporous layer; a macroporous layer disposed on the microporous layer.

2. The stent of claim 1 , wherein the macroporous layer comprises a columnar structure.

3. The stent of claim 1 , wherein the macroporous layer comprises a plurality of loops.

4. The stent of claim 3 , wherein the loops are stacked one on top of the other to form columns.

5. The stent of claim 4 , wherein the plurality of posts extend radially from an outer surface of the microporous layer.

6. 6. The stent of claim 4 or 5, wherein at least some of the plurality of struts have longitudinal axes that extend at an oblique angle relative to a longitudinal axis of the elongate tubular body.

7. 7. The stent of claim 6, wherein at least some of the plurality of posts extend at an acute angle between 0° and 90° relative to the longitudinal axis, and at least some of the plurality of posts extend at an obtuse angle between 90° and 180° relative to the longitudinal axis.

8. The stent of any one of claims 4 to 7, wherein at least some of the plurality of pillars have free ends oriented toward a centrally located pillar in the longitudinal direction.

9. The stent of any one of claims 4 to 8, wherein the density of the plurality of pillars increases toward the pillars located at the longitudinal center.

10. The stent of claim 3 , wherein one loop of the plurality of loops is at least partially laterally spaced from a preceding loop.

11. The stent of any one of claims 1 to 10, further comprising a second microporous layer disposed on the macroporous layer.

12. an elongated tubular body having a scaffold forming a plurality of cells and a covering extending over the scaffold to cover the plurality of cells of the scaffold; a woven sleeve disposed over at least a portion of the elongated tubular body; A stent wherein the woven sleeve is fabricated from one or more interwoven filaments that define a plurality of open cells.

13. 13. The stent of claim 12, wherein the entire length of the woven sleeve is positioned between a first flange proximate a first end of the elongated tubular body and a second flange proximate a second end of the elongated tubular body.

14. 14. The stent of claim 12 or 13, wherein the woven sleeve is removably disposed over the elongate tubular body.

15. The stent of any one of claims 12 to 14, wherein the woven sleeve is formed from a bioabsorbable fibrous material.

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