Stent with anti-migration features

Abstract

A stent and / or endoluminal implant for extending across two non-adhesive structures / tissues. An illustrative stent may include an elongate tubular body having a skeleton forming a plurality of cells; and a coating disposed over an outer surface of the elongated tubular body. The coating may include a first microporous layer and a macroporous layer including a plurality of rings disposed over the microporous layer.

Description

Cross - Reference to Related Applications

[0001] This application claims the benefit and priority of U.S. Provisional Patent Application Serial No. 63 / 422,519, filed on November 4, 2022, the disclosure of which is incorporated herein by reference. Technical Field

[0002] The present invention relates to medical devices, methods for manufacturing medical devices, and their uses. More particularly, the present invention relates to a stent for implantation into a body cavity or for transluminal implantation and associated methods. Background Art

[0003] A variety of in vivo medical devices have been developed for medical use, such as surgical and / or endovascular use. In some cases, physicians have been able to use stents to create a temporary opening between the gallbladder and the gastrointestinal (GI) tract to allow for the drainage of fluid from the gallbladder in the event of a blocked catheter. Without using this technique, another solution includes laparoscopic or percutaneous cholecystectomy, which is high risk for the elderly, critically ill patients, and patients with comorbidities. In known stents, endoluminal implants, and / or transluminal implants, there is a continuing need to provide alternative configurations of stents, endoluminal implants, and / or transluminal implants. Summary of the Invention

[0004] The present invention provides alternative designs, materials, manufacturing methods, and uses for medical devices. An example medical device may include a stent.

[0005] In a first example, a stent may include an elongated tubular body having a framework forming a plurality of compartments; and a coating disposed on an outer surface of the elongated tubular body. The coating may include a first microporous layer and a macroporous layer disposed on the microporous layer.

[0006] Alternatively or additionally to any of the above examples, in another example, the macroporous layer may include columnar structures.

[0007] Alternatively or additionally to any of the above examples, in another example, the macroporous layer may include a plurality of rings.

[0008] Alternatively or additionally to any of the above examples, in another example, the plurality of rings may be stacked on top of one another to form a plurality of columns.

[0009] Alternatively or additionally to any of the above examples, in another example, the plurality of columns may radially extend from an outer surface of the microporous layer.

[0010] Alternatively or additionally, for any of the above examples, in another example, at least some of the plurality of posts may have a longitudinal axis that extends at an oblique angle to the longitudinal axis of the elongate tubular body.

[0011] Alternatively or additionally, for any of the above examples, in another example, 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.

[0012] Alternatively or additionally, for any of the above examples, in another example, at least some of the plurality of posts may have a free end that is oriented towards the longitudinally centered post.

[0013] Alternatively or additionally, for any of the above examples, in another example, the density of the plurality of posts may increase towards the post located longitudinally in the center.

[0014] Alternatively or additionally, for any of the above examples, in another example, one of the plurality of rings may be at least partially laterally spaced apart from the previous ring.

[0015] Alternatively or additionally, for any of the above examples, in another example, the stent may further include a second microporous layer disposed on the macroporous layer.

[0016] In another example, a stent may include an elongate tubular body having a framework that forms a plurality of compartments and a covering that extends over the plurality of compartments of the framework; and a fabric sleeve disposed on at least a portion of the elongate tubular body. The fabric sleeve may be made of one or more interwoven filaments that define a plurality of open compartments.

[0017] Alternatively or additionally, for any of the above examples, in another example, the entire length of the fabric sleeve may be positioned between a first flange that is adjacent to the first end of the elongate tubular body and a second flange that is proximal to the second end of the elongate tubular body.

[0018] Alternatively or additionally, for any of the above examples, in another example, the fabric sleeve may be removably disposed on the elongate tubular body.

[0019] Alternatively or additionally, for any of the above examples, in another example, the fabric sleeve may be formed of a bioabsorbable textile material.

[0020] Alternatively or additionally, for any of the above examples, in another example, the fabric sleeve may be formed of a synthetic textile material.

[0021] In another example, a scaffold may include an elongate tubular body having a framework that forms a plurality of compartments; a first polymer matrix disposed on the elongate tubular body, the first polymer matrix including a first plurality of fibers that define a plurality of small pores and having a first density of the first plurality of fibers; and a second polymer matrix disposed on the elongate tubular body, the second polymer matrix including a second plurality of fibers that define a plurality of small pores and having a second density of the second plurality of fibers. The second density of the fibers may be less than the first density of the fibers.

[0022] Alternatively or additionally, for any of the above examples, in another example, the first polymer matrix may be configured to prevent tissue ingrowth.

[0023] Alternatively or additionally, for any of the above examples, in another example, the second polymer matrix may be configured to promote tissue ingrowth.

[0024] Alternatively or additionally, for any of the above examples, in another example, the first plurality of fibers and the second plurality of fibers may be electrospun.

[0025] Alternatively or additionally, for any of the above examples, in another example, the scaffold may further include a bioadhesive coating disposed on the second polymer matrix.

[0026] Alternatively or additionally, for any of the above examples, in another example, the diameter of the first plurality of fibers may be less than the diameter of the second plurality of fibers.

[0027] In another example, a scaffold may include an elongate tubular body having a framework that forms a plurality of compartments; a first polymer matrix disposed on the elongate tubular body, the first polymer matrix including a first plurality of fibers that define a plurality of small pores and having a first density of the first plurality of fibers; and a hydrogel adhesion layer disposed on the first polymer matrix.

[0028] Alternatively or additionally, for any of the above examples, in another example, the hydrogel adhesion layer may include gelatin, methacrylated gelatin (GelMA), polyethylene glycol (PEG)-based bioadhesive, or chitosan.

[0029] In another example, a scaffold may include an elongate tubular body having a framework that forms a plurality of compartments; a first polymer matrix disposed on the elongate tubular body, the first polymer matrix including a first plurality of fibers that define a plurality of small pores and having a first density of the first plurality of fibers; and a hemostatic agent layer disposed on the first polymer matrix.

[0030] Alternatively or additionally, for any of the above examples, in another example, the hemostatic layer may include kaolin and sodium montmorillonite.

[0031] The foregoing summary of some embodiments is not intended to describe every disclosed embodiment or every implementation of the present invention. The following drawings and detailed description more particularly exemplify these embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention can be more fully understood by considering the following detailed description of various embodiments in conjunction with the accompanying drawings, in which:

[0033] Figure 1 is a side view of an illustrative stent;

[0034] Figure 2 is Figure 1 a cross-sectional view of an illustrative stent of

[0035] Figure 3 is a schematic view of an illustrative stent implanted in a body of Figure 1 ;

[0036] Figure 4 is Figure 2 an enlarged cross-sectional view of a portion of an illustrative stent of

[0037] Figure 5 is a schematic view of an illustrative pattern of a macroporous layer;

[0038] Figure 6 is a schematic top view of an illustrative macroporous layer;

[0039] Figure 7A is a partial cross-section of a stent having an alternative macroporous layer with an alternative columnar structure and an outer microporous layer of Figure 1 ;

[0040] Figure 7B is a partial cross-section of a stent having an alternative macroporous layer and an outer microporous layer of Figure 1 ;

[0041] Figure 8A is a partial perspective view of a portion of a stent having an alternative macroporous layer of Figure 1 ;

[0042] Figure 8B is a partial perspective view of a portion of a stent having an alternative macroporous layer of Figure 1 ;

[0043] Figure 9A is a partial schematic cross-sectional view of an illustrative stent depicting another illustrative arrangement of a plurality of columns of Figure 1 ;

[0044] Figure 9B is Figure 9A an enlarged view of a portion of a stent;

[0045] Figure 10 is a partial schematic cross-sectional view of an illustrative stent depicting another illustrative arrangement of a plurality of struts; Figure 1 of an illustrative stent;

[0046] Figure 11A is a schematic top view of an illustrative polymer matrix;

[0047] Figure 11B is a schematic top view of another illustrative polymer matrix;

[0048] Figure 12 is an enlarged cross-sectional view of a portion of an illustrative stent having an alternative coating; and Figure 2 of an illustrative stent;

[0049] Figure 13 is a side view of an illustrative outer layer for use with a stent.

[0050] While the invention is susceptible to various modifications and alternative forms, specific details thereof have been shown by way of example in the drawings and will be described in more detail. It should be understood, however, that the invention is not intended to limit the various aspects of the invention to the particular embodiments described. On the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the scope of the invention. Detailed Description

[0051] For the terms defined below, unless a different definition is given in the claims of this specification or elsewhere, these definitions shall apply.

[0052] All numerical values herein are assumed to be modified by the term "about" whether or not explicitly indicated. The term "about" generally refers to a range of numbers that a person of ordinary skill in the art would consider equivalent to the recited number (i.e., having the same function or result). In many instances, the term "about" may indicate numbers that include the number rounded to the nearest significant figure.

[0053] The recitation of a numerical range by endpoints includes all numbers within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

[0054] Although some suitable dimensions, ranges, and / or values have been disclosed for various components, features, and / or specifications, those skilled in the art to which the invention pertains will understand that desired dimensions, ranges, and / or values can be derived from those explicitly disclosed.

[0055] As used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally employed in its sense including "and / or" unless the context clearly dictates otherwise.

[0056] 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 the drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the invention. The illustrative embodiments depicted are merely exemplary. Any selected features of any illustrative embodiment may be incorporated into additional embodiments unless expressly stated to the contrary.

[0057] In some cases, physicians have been able to create an anastomosis or a temporary opening between the gallbladder and the gastrointestinal (GI) tract using a stent or a transluminal implant to allow for drainage of fluid from the gallbladder in the event of catheter blockage. Without using this technique, another solution involves laparoscopic or percutaneous cholecystectomy, which is high risk for the elderly, critically ill, and patients with comorbidities. Although this technique has helped make significant progress in patient care, there are still challenges associated with transluminal drainage. For example, placing a stent between two non-adherent structures (e.g., gastrojejunostomy, hepaticogastrostomy, or gallbladder drainage into the stomach or duodenum, etc.) to form an anastomosis is technically challenging due to the lack of tools for visualization, stabilization, and in some cases for inflating the target site. These challenging situations may result in the stent being unable to create a hold between the two non-adherent structures / tissues. All of these challenges can lead to a failed procedure with severe complications. There may be a need for a device and an associated method that make it easier to perform the postoperative process on a patient and reduce long-term complications. Although the present invention is discussed in terms of a transluminal implant for forming an anastomosis, it should be understood that the devices described herein may also be endoluminal implants. Additionally, the location of the implant is not limited to a specific anatomical location.

[0058] Figure 1 A side view of an illustrative implant 10, such as, but not limited to, a stent, is shown. Figure 2 A cross-sectional view of the illustrative stent 10 taken along Figure 1 line 2-2 is shown. Figure 3A schematic view of an illustrative stent 10 implanted in a patient's body to form an anastomosis is shown. In some cases, the stent 10 may be formed of an elongate tubular member 12. Although the stent 10 is described as being generally tubular, it is contemplated that the stent 10 may assume 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 end 14 and the second end 16. The stent 10 may include a lumen 20 extending from a first opening adjacent the first end 14 to a second opening adjacent the second end 16 to permit fluid etc. to pass therethrough.

[0059] The stent 10 may be radially expanded from a first radially collapsed configuration (not explicitly shown) to a second radially expanded configuration, as Figures 1 to 3 shown. The stent 10 may be configured to extend across two non-adherent structures / tissues and apply a radially outward pressure to create an opening or passageway between the two non-adherent structures / tissues, thereby forming an anastomosis between two separate anatomical structures.

[0060] The tubular member 12 of the stent 10 may have a skeletal structure made of one or more or a plurality of intertwined filaments or struts 22. The skeletal structure may extend from the first end 14 to the second end 16 of the stent 10. For example, the skeletal structure and thus 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 with a single filament that intertwines with itself (e.g., knitted) to form the skeletal structure. In other embodiments, the stent 10 may be formed with several intertwined filaments (e.g., braided) to form the skeletal structure. Thus, in such cases, one or more of the filaments forming the skeletal structure may extend continuously from the first end 14 to the second end 16 of the stent 10. In another embodiment, the stent 10 may include a laser-cut tubular member to form the skeletal structure. The laser-cut tubular member may have an open lattice and / or closed-cell geometry that includes one or more interconnected struts formed integrally from the tubular member. In such cases, the laser-cut tubular member forming the skeletal structure may extend continuously from the first end 14 to the second end 16 of the stent 10.

[0061] In some cases, the inner surface and / or outer surface of the skeletal structure of the stent 10 may be completely, substantially, or partially covered with a polymer covering or layer 24, 26 (see, for example, Figure 2)。For example, the covering or coating can extend across the open cells of the skeletal structure to prevent tissue ingrowth into the lumen of the stent 10. However, in some embodiments, one or both of the polymeric coverings 24, 26 can be omitted. For example, in some embodiments, the stent 10 can include only the outer polymeric covering 26 on the outer surface of the skeletal structure. In other embodiments, the stent 10 can include only the inner polymeric covering 24 on the inner surface of the skeletal structure. In some cases, the inner layer 24 and the outer layer 26 can be formed as an integral structure. In other embodiments, the inner layer 24 and the outer layer 26 can be formed as separate layers. The inner layer 24 and the outer layer 26 can be formed of the same material or different materials as needed. The inner layer 24 and / or the outer layer 26 can span or be disposed within an opening or void defined between adjacent stent filaments or struts 22 of the skeletal structure, as Figure 4 more clearly shown in Figure 4 which shows an enlarged view of a portion of the stent 10 shown in dashed lines in Figure 2 . It should be understood that since the inner layer 24 and the outer layer 26 extend outwardly and inwardly, respectively, they can contact and / or form an interfacial region within a space (e.g., an opening, a hole, a void) 23 in the wall of the skeletal structure 10 of the stent 10. For example, Figure 4 the detailed view of

[0062] shows that the inner layer 24 and the outer layer 26 can extend into the opening 23 defined between adjacent stent struts 22 and form an interfacial region. Additionally, the inner layer 24 and the outer layer 26 can additionally extend between adjacent filaments or struts 22, thereby filling any space between adjacent filament or strut members 22 and thus preventing tissue ingrowth into the lumen of the stent 102.

[0063] It is contemplated that the skeletal structure, e.g., the filaments and / or struts of the stent 10, can be made of a variety of different materials as needed, such as but not limited to metals, metal alloys, shape memory alloys, and / or polymers, such that the stent 10 can expand to an appropriate shape when accurately positioned within the body. In some cases, the material can be selected such that the stent 10 can also be relatively easily removed. For example, the stent 10 can be formed of an alloy, such as but not limited to Nitinol and Elgiloy formed. Depending on the material selected for construction, the stent 10 can be self-expanding or require an external force to radially expand the stent 10. In some embodiments, filaments can be used to fabricate the stent 10, which can be composite filaments, e.g., having a sheath made of Nitinol and a platinum core. It is also contemplated that the filaments of the stent 10 can be formed of a polymer, including but not limited to polyethylene terephthalate (PET).

[0063] In some cases, in a radially expanded configuration, the stent 10 can include a first end region 28 adjacent to the first end 14 and a second end region 30 adjacent to the second end 16. In some embodiments, the first end region 28 and the second end region 30 can include shoulders or enlarged regions, such as flanges 32, 34 positioned near the first end 14 and the second end 15 of the stent 10. The flanges 32, 34 can be configured to engage an inner portion of the wall of a body cavity or lumen. For example, the first flange 32 can be positioned against the interior of a first lumen, and the second flange 34 can be positioned against the interior of a second lumen different from the first lumen. Thus, the stent 10 can be positioned to span between two separate anatomical structures. For example, referring to Figure 3 , the stent 10 is positioned such that it extends between the gallbladder 90 and the duodenum 92. The first flange 32 can be positioned within the gallbladder 90, and the second flange 34 can be 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 can extend through the wall 94 of the gallbladder 90 and the wall 96 of the duodenum 92. In some cases, the first flange 32 can contact the interior of the wall 94 of the gallbladder 90, and / or the flange 34 can contact the interior of the wall 96 of the duodenum. However, this is not required.

[0064] In some embodiments, the flanges 32, 34 can have a larger diameter than the intermediate region or body 18 of the stent 10 located between the end regions 28, 30 to prevent or help prevent migration of the stent 10 once placed within a body cavity, lumen, or across a body cavity or lumen. It is contemplated that the transition from the cross-sectional area of the central region or body 18 to the retention features or flanges 32, 34 can occur gradually, obliquely, or in a sudden stepped manner as needed. In some cases, the flanges 32, 34 can have a curved hemispherical shape with a gradually increasing cross-sectional size and then a gradually decreasing cross-sectional size in one direction such that the first end 14 and / or the second end 16 have a cross-sectional size similar to the intermediate region or body 18. However, this is not required. Other shapes and / or configurations can be used as needed.

[0065] 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 greater than the outer diameter of the intermediate region or the body 18. In some cases, the first outer diameter and the second outer diameter may be substantially the same, while in other cases, 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 if desired, the stent 10 may not include a flange. For example, the first end region 28 may include the flange 32, while the second end region 30 may have an outer diameter similar to that of the intermediate region or the body 18. It is also contemplated that the second end region 30 may include the flange 34, while the first end region 28 may have an outer diameter similar to the outer diameter of the intermediate region or the 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 central region or the 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 vary to suit the desired application.

[0066] As Figure 4 can be seen more clearly in, in some embodiments, the outer surface of the stent 10 may include a coating 36, which is configured to facilitate the ingrowth of tissue into the stent 10 postoperatively and / or after implantation. The coating 36 may be deposited on at least a portion of the outer covering 26, or in the absence of the outer covering 26, on at least a portion of the inner covering 24. In the absence of the inner and / or outer coverings 24, 26, the coating 36 may be provided on the struts 22 and / or within at least a portion of the plurality of openings 23. In some cases, the coating 36 may be configured to induce the ingrowth of new tissue around and through the stent 10. Briefly referring to Figure 3 the example of, the coating 36 may be configured to induce tissue growth such that the openings formed through the walls 94, 96 of the cavities 90, 92 become a natural part of the body. For example, in such a case, the orifice will remain open whether or not the stent 10 is in place to permanently drain the gallbladder. The stent 10 may be placed in the desired treatment location and left in place until tissue ingrowth has formed a natural orifice or path between two non-adherent tissues / structures. It is contemplated that the ingrowth of new healthy tissue around the stent 10 may reduce the likelihood of stent migration, as the healthy tissue may grip the stent 10 and the natural peristalsis of the body may not be sufficient to move the stent 10 out of the ingrown tissue. However, in some cases, if desired, the stent 10 may still be removed endoscopically after a few weeks, leaving a conduit of newly formed tissue spanning two non-adherent tissues / structures to form an anastomosis therebetween.

[0067] ReturnFigure 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 may enhance cell adhesion to the surface of the stent 10 to limit stent migration, while the macroporous layer 40 may facilitate the growth of vascular structures along the surface of the stent 10 to promote the formation of an anastomosis. For example, the inner microporous layer 38 may facilitate cell attachment, while the outer macroporous layer 40 may facilitate tissue ingrowth. It is also contemplated that the coating 36 may inhibit or limit the foreign body response. The inclusion of the inner microporous layer 38 and the macroporous layer 40 may promote the formation of an anastomosis from natural tissue growth between the gallbladder 90 and the stomach / duodenum 92 (or other two non-adherent structures / tissues) without causing the stent 10 to migrate out of position. In some cases, as new tissue ingrowth occurs, the inner microporous layer 38 and / or the outer macroporous layer 40 may be absorbed into the body tissue over time. As tissue grows from the two non-adherent structures, the tissue from each of the non-adherent structures may grow together or join to form a tissue conduit between the non-adherent structures. This may allow the formed tissue anastomosis to remain in the body even after the stent 10 (having the inner layer 24 and the outer layer 26) is removed.

[0068] The coating 36 may be formed by any desired process. For example, the coating 36 may be formed by a combination of spraying and direct ink writing (DIW). For example, the inner microporous layer 38 may be created by spraying the stent 10 with a sprayable ink. As used herein, "ink" may be a liquid for printing the inner microporous layer 38 on the stent 10. The ink may be sprayed in liquid form and any solvent will evaporate, leaving behind a solid with a micropatterned texture. In some cases, it may be necessary to cure the inner microporous layer 38 to solidify the coating. The inner microporous layer 38 may have interconnected small pores in the range of 2 micrometers (μm) or less, 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 additives that are configured to increase porosity by removing the additives after curing the sprayable ink.

[0069] The macroporous layer 40 can be formed by extruding a high-viscosity material, for example, using 3D printing, onto the scaffold 10 to form columnar structures extending over the microporous layer 38. In some cases, the columnar structures can include a plurality of columns extending from the microporous layer 38 with spaces therebetween. In some cases, the columnar structures forming the macroporous layer can be considered a coiled rope layer. The coiled rope layer derives its name from the tendency of the material to coil like a rope as it exits the extruder. It is contemplated that the material can have a viscosity that allows the material to maintain the cross-sectional dimensions of the extruder when applied to the scaffold 10. For example, the material may be anti-flowable during and / or after extrusion. It is contemplated that the material can be any biocompatible or bioabsorbable material as needed. The thickness of the macroporous layer 40 can have a thickness in the range of at least 1 micrometer (μm) to at least one millimeter (mm), such as, for example, 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 (measured in a direction extending outward from the outer surface of the microporous layer 38). The pattern of the macroporous layer 40 can be determined at least in part by the speed of movement of the scaffold 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 scaffold 10. For example, if the scaffold 10 moves relative to the extruder, the material can form a plurality of rings, and if the scaffold 10 is stationary, the rings can coil on top of each other to form vertically ascending windings (e.g., similar to a spring).

[0070] Figure 5A schematic diagram showing an illustrative pattern 100 of the macroporous layer 40 when the stent 10 is moved relative to the extruder. The macroporous layer 40 can be formed as one or more rows 112 of a plurality of rings 102a, 102b, 102c (collectively 102). The rings 102 can each include ring portions 104a, 104b, 104c (collectively 104) and overlapping base portions 106a, 106b, 106c (collectively 106). The overlapping base portions 106a, 106b, 106c are understood to be part of the ring 102, where a segment of a filament overlaps or crosses a second segment of the filament, and the segments of the filament forming the ring portions 104a, 104b, 104c extend therebetween. In the illustrated pattern 100, there are gaps 108a, 108b between adjacent ring portions 104 such that subsequent rings 102b, 102c do not contact the previous rings 102a, 102b. However, this is not necessary. The pattern 100 can be formed such that adjacent rings 102 overlap each other. The amount of overlap can range from one ring 102 formed on top of another to adjacent ring portions 104 that just touch each other. For example, the distances 110a, 110b (collectively 110) between similar positions on adjacent rings 102 can be zero or substantially zero such that the rings 102 are vertically stacked on top of each other. In other cases, the distance 110 between similar positions on adjacent rings 102 can be less than the width of the ring 102 such that the subsequent ring is partially formed on the previous ring 102. It is also contemplated that laterally adjacent rings 102 can be unconnected to each other. For example, in some cases, the rings 102 can form a first column of vertically extending stacked rings 102, as will be described in more detail herein.

[0071] Figure 6 An enlarged top view showing a portion of the macroporous layer 40 is shown. The macroporous layer 40 can include a plurality of layers 114a, 114b (collectively 114), each having a plurality of rows 112a-h formed by a plurality of rings 102a-f, where not all of the rings are formally identified with reference numerals for the sake of brevity and ease of understanding. The innermost layer 114a can be applied to the outer surface of the stent 10 (e.g., on the inner microporous layer 38), and then the outer layer 114b is positioned on the inner layer 114a. In some cases, the inner microporous layer 38 and the macroporous layer 40 can be directly applied and adhered to the outer surface (e.g., the outer layer 26, if so provided), while in other cases, the inner microporous layer 38 and the macroporous layer 40 can be applied to a sleeve positioned on the outer surface of the stent 10 but not necessarily coupled thereto. Although Figure 6 Two layers 114 are shown, but it is contemplated that the macroporous layer 40 can include fewer or more than two layers as needed.

[0072] The first layer 114a can be formed by rotating the stent 10 about its longitudinal axis (relative to the extruder) while the material is extruded to form a circumferentially extending row 112a. The stent 10 can then be axially displaced and another circumferentially extending row 112b can be deposited. This operation can be repeated for multiple rows as needed. In another example, the first layer 114a can be formed by axially displacing the stent 10 (relative to the extruder) while the material is extruded to form a longitudinally extending row. The stent 10 can then be rotated about the longitudinal axis and another longitudinally extending row can be deposited. This operation can be repeated for multiple rows as needed.

[0073] Once the first layer 114a is complete, one or more additional layers 114b can be deposited on the previous layer. In Figure 6 the illustrated embodiment, a second layer 114b is shown such that the rows 112e-h are vertically and horizontally offset from the rows 112a-d of the first layer 114a. However, this is not required. In some cases, the second layer 114b can be applied such that the rows 112e-h (and corresponding loops 102d-f) are aligned with or stacked on the rows 112a-d (and corresponding loops 102a-c) of the previous layer 114a. In other examples, the second layer 114b can be applied at an angle relative to the first layer 114a. For example, the rows 112e-h of the second layer 114b can be non-parallel to the rows 112a-d of the first layer 114a. In other examples, the rows 112e-h of the second layer 114b can be vertically and horizontally offset from the rows 112a-d of the first layer 114a.

[0074] The inner microporous layer 38 and / or the macroporous layer 40 can be deposited on the entire outer surface of the stent 10 or less than the entire outer surface as needed. For example, in some cases, the inner microporous layer 38 and / or the macroporous layer 40 can be deposited on the intermediate region or body 18 of the stent 10 extending between the flanges 32, 34, as Figure 2 shown, while the flanges 32, 34 may be without the inner microporous layer 38 and / or the macroporous layer 40. However, it should be understood that the inner microporous layer 38 and / or the macroporous layer 40 can be deposited in any desired pattern, including a uniform pattern, an eccentric 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 microporous layer 38 and / or the macroporous layer 40 can be selectively deposited on the stent 10 to control the fixation characteristics of the stent 10 to the target treatment site.

[0075] In some examples, the surface of the stent 10 can be mapped or scanned prior to depositing the inner microporous layer 38 and / or the macroporous layer 40. This can allow the control panel of the extruder to understand the topography of the surface and apply the coating 36 to a desired height. For example, the extruder can be configured to apply the coating 36 in a manner that allows the outer surface to have a uniform outer dimension regardless of any variations in the cross-sectional dimensions of the substrate (e.g., the backbone structure of the stent 10).

[0076] Figure 7A is a partial cross-section of a stent 10 having an alternative macroporous layer 40' with an alternative ring arrangement. The coating 36 can include a first or inner microporous layer 38 and a second or intermediate macroporous layer 40' positioned above or external to the inner microporous layer 38, and a third or outer microporous layer 42 positioned above or external to the macroporous layer 40'. The macroporous layer 40' can include columnar structures, such as a plurality of posts 44. Each post 44 can be formed by a plurality of wound rings 46 that are stacked on top of one another like a rope coil or a spring and extend radially outward from the microporous layer 38. While the posts 44 are shown as each having five rings 46, each post 44 can also have fewer than five or more than five rings 46 as needed to achieve a desired height. It is also contemplated that the posts 44 can have different numbers of rings 46 to create posts 44 having different heights. The posts 44 can be axially and / or circumferentially spaced from one another in any desired arrangement. In some examples, two or more of the posts 44 can be in contact with one another.

[0077] The outer microporous layer 42 can be created by spraying the stent 10 with a sprayable ink after depositing the macroporous layer 40'. The ink can be sprayed in a liquid form, and any solvent will evaporate, leaving behind a solid with a micropatterned texture. In some cases, it may be necessary to cure the outer microporous layer 42 to solidify the coating. The outer microporous layer 42 can have interconnected small holes 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 can have a thickness in the micrometer range. For example, the outer microporous layer 42 can 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 can be a sprayable silicone ink. It is contemplated that the sprayable ink can include additives that are configured to increase porosity by removing the additives after curing the sprayable ink.

[0078] In some embodiments, the outer microporous layer 42 can be formulated to provide additional nutrients to further promote ingrowth of cells inwardly. For example, the outer microporous layer 42 can comprise or be derived from a nutrient solution, such as, but not limited to, nutrient agar or nutrient broth. Alternatively or additionally, a coating comprising or derived from a nutrient solution can be sprayed or otherwise deposited on the outer microporous layer 42 (or on the macroporous layers 40, 40' in the absence of the outer microporous layer 42). Nutrient solutions are typically used in tissue cultures to promote tissue growth in micropropagation cultures and similarly to promote tissue growth in vivo postoperatively. Such an added spray / coating can be continued for a predetermined length of time, such as a few days or weeks, after which the stent 10 (if applicable) can be removed and the body will naturally form an anastomosis where natural tissue grows and connects between the gallbladder and the duodenum or stomach (or other two non-adherent tissues / structures).

[0079] The inner microporous layer 38, the macroporous layer 40', and / or the outer microporous layer 42 can be deposited on the entire outer surface of the stent 10 or less than the entire outer surface as needed. For example, in some cases, the inner microporous layer 38, the macroporous layer 40', and / or the outer microporous layer 42 can be deposited on an intermediate region or body 18 of the stent 10 that extends between the flanges 32, 34, while the flanges 32, 34 can be without 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 can be deposited in any desired pattern, including a uniform pattern, an eccentric arrangement, less than the entire circumference of the stent 10, less than the entire length of the stent 10, combinations thereof, etc.

[0080] As Figure 7A shown, the outer microporous layer 42 can extend over a columnar structure formed by a plurality of posts 44 and span the space between adjacent posts 44. By spanning the space between adjacent posts 44, a void 45 can be defined between the outer surface of the inner microporous layer 38 between adjacent posts 44 and the outer microporous layer 42. The void 45 can allow tissue to grow inwardly therein after implantation, which can facilitate the formation of a tissue conduit to form an anastomosis between two anatomical structures.

[0081] In Figure 7B an alternative configuration shown, the outer microporous layer 42 can extend over a columnar structure formed by a plurality of posts 44 and extend radially inwardly in the space between adjacent posts 44 to contact the outer surface of the inner microporous layer 38 between adjacent posts 44.

[0082] Figure 8A Another configuration of the macroporous layer 40'' extending over the inner microporous layer 38 is shown. It should be noted that, for clarity,[[]] Figure 8A the outer microporous layer 42 is excluded, but the outer microporous layer 42 can be provided on the macroporous layer 40'', asFigure 7A or Figure 7B As shown. The macroporous layer 40'' may include a columnar structure formed by a plurality of pillars, such as elongated baffles or partitions 47. The baffles or partitions 47 may extend longitudinally, circumferentially, sinusoidally, or in another starting point or arrangement. The baffles or partitions 47 may extend between the outer surface of the inner microporous layer 38 and the inner surface of the outer microporous layer 42, thereby providing a void therebetween for tissue ingrowth. The baffles or partitions 47 may be formed similarly to the column 44 discussed above, by a multi-layer 3D printing process.

[0083] Figure 8B Another configuration of the macroporous layer 40''' extending over the inner microporous layer 38 is shown. It should be noted that, for clarity, Figure 8B the outer microporous layer 42 is excluded, but the outer microporous layer 42 may be provided on the macroporous layer 40''', as Figure 7A or Figure 7B shown. The macroporous layer 40''' may include a columnar structure formed by a plurality of pillars, such as walls or struts 49. The walls or struts 49 may extend in any desired starting point or arrangement. The walls or struts 49 may extend between the outer surface of the inner microporous layer 38 and the inner surface of the outer microporous layer 42, thereby providing a void therebetween for tissue ingrowth.

[0084] Figure 9AFIG. 0 shows a partial schematic cross-sectional view of an illustrative stent 10 depicting another illustrative arrangement of a columnar structure including a plurality of posts 52a-m (collectively 52) forming another illustrative macroporous layer. The posts 52 may be similar in form and function to the posts 44 described herein. In the illustrated embodiment, the posts 52 may be deposited such that tissue growth from two different non-adherent tissues / structures is towards each other (e.g., towards the central post 52g). For example, the macroporous layer 40 may include a first set 48 of posts 52a-f that extend from a position adjacent to the first flange 32 and towards the midpoint of the posts 52 at an inner point of the body 18 of the stent 10 (e.g., towards the intermediate post 52g); and a second set 50 of posts 52h-m that extend from a position adjacent to the second flange 34 and towards the midpoint of the posts 52 at an inner point of the body 18 of the stent 10 (e.g., towards the centrally located post 52g). Although the intermediate post 52g is shown centered along the length of the stent 10, this is not required. In some cases, the midpoint of the posts 52 may not correspond to the midpoint of the stent 10, but may be located at different inner positions along the body 18 of the stent 10. The posts 52a-f of the first set 48 may be oriented such that the longitudinal axes of the posts 52a-f extend at a non-orthogonal angle (e.g., an oblique angle) relative to the longitudinal axis of the stent 10 such that the free end of each of the posts 52a-f (e.g., radially spaced from the stent 10) points towards the centrally located post 52g. Similarly, the posts 52h-m of the second set 50 may also be oriented such that the longitudinal axes of the posts 52h-m extend at a non-orthogonal angle (e.g., an oblique angle) relative to the longitudinal axis of the stent 10 such that the free end of each of the posts 52h-m (e.g., radially spaced from the stent 10) points towards the centrally located post 52g. It should be noted that, for clarity, Figure 9A the outer microporous layer 42 is excluded, but the outer microporous layer 42 may be provided on the macroporous layer 40 as Figure 7A or Figure 7B shown.

[0085] Figure 9B shows Figure 9AAn enlarged view of a portion of the bracket 10 shown in dashed lines. The centrally or centered post 52g may have a longitudinal axis 56 that is at a generally orthogonal angle 58 with respect to the longitudinal axis 54 of the bracket 10. The posts 52a-f of the first set 48 may extend at an oblique angle between 0° and 90° with respect to the longitudinal axis. The angles of the posts 52a-f of the first set 48 may be uniform along the length of the bracket 10, or the angles of the posts 52a-f of the first set 48 may gradually increase toward the centrally located post 52g. For example, the first post 52f adjacent to the centrally located post 52g may have a longitudinal axis 60 that extends at a first non-orthogonal angle 62 (e.g., an acute angle) with respect to the longitudinal axis 54 of the bracket 10, and the next second post 52e may also have a longitudinal axis 64 that extends at a second non-orthogonal angle 66 (e.g., an acute angle) 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 set 48 may have an acute angle that is less than the acute angle of the adjacent post 52a-f. However, this is not required. In some cases, each of the posts 52a-f in the first set 48 may have the same non-orthogonal angle (e.g., an acute angle). In other embodiments, the angles of the posts 52a-f of the first set 48 may vary in an eccentric or non-uniform manner.

[0086] The posts 52h-m of the second set 50 may extend at an oblique angle between 90° and 180° with respect to the longitudinal axis. The angles of the posts 52h-m of the second set 50 may be uniform along the length of the bracket 10, or the angles of the posts 52h-m of the second set 50 may gradually decrease toward the centrally located post 52g. For example, the first post 52h adjacent to the centrally located post 52g may have a longitudinal axis 68 that extends at a third non-orthogonal angle 70 (e.g., an obtuse angle) with respect to the longitudinal axis 54 of the bracket 10, and the next second post 52i may also have a longitudinal axis 72 that extends at a fourth non-orthogonal angle 74 (e.g., an obtuse angle) 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 set 50 may have an obtuse angle that is greater than the obtuse angle of the adjacent post 52h-m. However, this is not required. In some cases, each of the posts 52h-m in the second set 50 may have the same non-orthogonal angle (e.g., an obtuse angle). In other embodiments, the angles of the posts 52h-m of the first set 50 may vary in an eccentric or non-uniform manner.

[0087] Figure 10FIG. 0 shows a partial schematic cross-sectional view of an illustrative stent 10 depicting another illustrative arrangement of a columnar structure including a plurality of posts 80a-k (collectively 80) forming another illustrative macroporous layer 40””’. The posts 80 may be similar in form and function to the posts 44 described herein. The posts 80 may extend radially from the outer surface of the inner microporous layer 38. Although the posts 80 are shown as generally extending orthogonally to the longitudinal axis of the stent 10, it is contemplated that one or more of the posts 80 may extend at a non-orthogonal angle, if desired. In the illustrated embodiment, the posts 80 may be deposited such that tissue growth from two different non-adherent tissues / structures is towards each other (e.g., towards the central post 80f). For example, the posts 80 may have varying longitudinal and / or circumferential spacing along the length and / or circumference of the stent 10. Although the central post 80f is shown as being centered along the length of the stent 10, this is not required. In some cases, the midpoint of the struts 80 may not correspond to the midpoint of the stent 10.

[0088] In some cases, the longitudinal and / or circumferential spacing between adjacent posts 80 may decrease towards the central post 80f such that the density of the posts 80 is greater near the central post 80f compared to near the first or second flanges 32, 34. For example, there may be a first distance 82 between the most distal post 80k (closest to the distal end 16) and the adjacent post 80j proximal thereto. For example, there may be a second distance 84 between the second post 80j from the distal end and the adjacent post 80i proximal thereto. 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 adjacent post 80g distal thereto. The third distance 86 may be less than the first or second distance 82, 84. The posts 80a-80e proximal to the centrally located post 80f (e.g., closer to the proximal end 14) may have a similar spacing arrangement where the distance between adjacent posts 80 decreases towards the central post 80f. Although the spacing between the posts 80 is shown in relation to the longitudinal spacing, it is contemplated that the circumferential spacing may also decrease towards the central post 80f, although this is not required. In other examples, the longitudinal spacing may remain constant while the circumferential spacing decreases towards the central post 80f. In other embodiments, the longitudinal and circumferential spacing of the posts 80 may increase towards the central post 80f, or the posts may be spaced unevenly or eccentrically.

[0089] After implanting the stent 10 to create an anastomosis between two separate anatomical structures, tissue can grow from one or both anatomical structures (e.g., the gallbladder and the gastrointestinal (GI) tract) along the macroporous layers 40, 40', 40", 40"', 40"", 40""" into the void space to form a tissue conduit around the stent 10 by natural tissue. For example, as described above, the inner microporous layer 38 can facilitate cell attachment, while the outer macroporous layer 40 can facilitate tissue ingrowth. It is also contemplated that the coating 36 can inhibit or limit the foreign body response. The inclusion of the inner microporous layer 38 and the macroporous layer 40 can promote natural tissue growth of the anastomosis between the gallbladder 90 and the stomach / duodenum 92 (or other two non-adherent structures / tissues) without causing the stent 10 to migrate out of position. In some cases, as new tissue ingrowth occurs, the inner microporous layer 38 and / or the outer macroporous layer 40 can be absorbed into the body tissue over time. As tissue grows from both non-adherent structures, the tissue from each of the non-adherent structures can grow together or join to form a tissue conduit between the non-adherent structures. In some cases, once sufficient natural tissue has formed along the body 18 of the stent 10, the stent 10 can be removed, leaving a natural tissue conduit as the anastomosis between the anatomical structures (e.g., the gallbladder and the gastrointestinal (GI) tract) for fluid drainage therebetween.

[0090] In some embodiments, the coating 36 can comprise a polymer matrix. Figure 11AIs a schematic top view of an illustrative polymeric matrix. The polymeric matrix 200 can include multiple fibers 202 that define multiple small holes 204 (e.g., voids). The multiple fibers 202 can be disposed above the multiple struts 22 and the multiple openings 23 of the tubular member 12 (e.g., provide a porous matrix above the tubular member 12). Each of the multiple fibers 202 can have a diameter in the range of from about 100 nanometers (nm) to about 900 nm, such as 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 can have the same diameter, or the multiple fibers 202 can include fibers having different sizes. It should be understood that the diameter of the fibers 202 can at least partially determine the size of the small holes 204 defined between adjacent fibers 202. It is also contemplated that the diameter of the fibers 202 can at least partially determine the amount of tissue ingrowth that can occur through the polymeric matrix 200. For example, fibers 202 having a diameter in the range of greater than about 500 nanometers (nm) can promote tissue ingrowth, while a diameter less than 500 nm may cause the polymeric matrix 200 to be a barrier to tissue ingrowth. The thickness of the polymeric matrix 200 can range from at least 1 micrometer (μm) to at least one millimeter (mm), such as, for example, 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 polymeric matrix 200 can at least partially determine the ease of removability of the stent 10. For example, compared to a thicker polymeric matrix 200, a thinner polymeric matrix 200 can allow less tissue ingrowth. Less tissue ingrowth can increase the removability of the stent 10. Some illustrative polymeric matrices can be found in U.S. Patent Application Publication No. 2022 / 0296396, commonly assigned and entitled Medical Implantable Devices and Methods of Use Thereof, published on September 22, 2022, the disclosure of which is incorporated herein by reference.

[0091] As porous, the polymer matrix 200 may permit one or more materials to pass through the polymer matrix 200. For example, as described in further detail herein, the polymer matrix 200 may permit tissue to grow between multiple fibers 202 and through multiple small holes 204. The size (e.g., thickness, diameter, etc.) of the multiple fibers 202 and / or the size of the multiple small holes 204 may at least partially determine the growth rate of the tissue through the polymer matrix 200. In some embodiments, the multiple fibers 202 may be sintered to strengthen the material composition of the multiple fibers 202 and reduce the brittleness of the polymer matrix 200. According to some examples herein, the porosity of the polymer matrix 200 may remain substantially consistent when sintering the multiple fibers 202. Additionally, for example, the porosity of the polymer matrix 200 may be fine-tuned to allow for sufficient degradation and cell growth penetration between the multiple fibers 202 and through the multiple small holes 204.

[0092] In some examples, the scaffold 10 may include two or more layers of the polymer matrix 200. It is contemplated that the layers may be extremely thin layers, one stacked on top of the other, to achieve the desired thickness. In some examples, the layers may have similar properties. For example, each layer may have a similar porosity and / or contain fibers of similar size. However, this is not required. In some cases, different layers may provide different properties. Figure 11B is a schematic top view illustrating another illustrative polymer matrix 210. The polymer matrix 210 may include multiple fibers 212 that define multiple small holes 214 (e.g., voids). The multiple fibers 212 may be similar in form and function to the multiple fibers 202 described herein. It is contemplated that the density of the multiple fibers 212 of the polymer matrix 210 may be greater than Figure 11A the density of the multiple fibers 202 of the polymer matrix 200. Figure 11B The density of the multiple fibers 212 of the polymer matrix 210 may prevent tissue ingrowth. It is contemplated that Figure 11B the polymer matrix 210 may be positioned between the scaffold 10 and Figure 11A the polymer matrix 200. It is contemplated that positioning the polymer matrix 210 with a greater density between the polymer matrix 200 with a lower density (which is configured to encourage tissue ingrowth) and the tubular member 12 may allow tissue to ingrow to a specified depth (e.g., the thickness of the polymer matrix 200 with a lower density), but prevent tissue from ingrowing to reach the struts 22 of the scaffold 10. In some cases, the polymer matrix 210 with a greater density may provide a lubricious insulating layer between the target tissue and the struts 22 of the scaffold 10.

[0093] The polymer matrix 200 can be formed over the tubular member 12 by any suitable technique, including, for example, electrospinning. For example, a polymeric material can be electrospun over the tubular member 12 to form the polymer matrix 200. Exemplary polymeric materials include, but are not limited to, thermoplastic polymers, including fluoropolymers, which can be electrospun when in the form of a liquid solution. The material can be delivered with high electrical power such that the material can be deposited over the exterior of the tubular member 12 in a random, asymmetric, and / or irregular pattern. The solvent in the liquid solution can evaporate and form polymer chains, e.g., become mechanically entangled. The resulting structure can include multiple fibers 202 deposited onto the tubular member 12. In some embodiments, the polymer matrix 200 can include polyvinylidene fluoride, polyvinylidene difluoride (PVDF), and / or hexafluoropropylene (HFP).

[0094] As Figure 11A seen, the multiple fibers 202 can be intertwined with each other over the multiple struts 22. It should be understood that the multiple fibers 202 can be further intertwined with the outer surface of the tubular member 12, such as, but not limited to, the inner and / or outer coverings 24, 26 (if so provided), to secure the polymer matrix 200 to the tubular member 12. The multiple fibers 202 can be mixed with the material of the outer layer 26. The outer layer 26 can include a polymer, such as, for example, silicone. Thus, during the electrospinning process of generating the polymer matrix 200 over the tubular member 12, the material electrospun onto the tubular member 12 (e.g., a fluoropolymer) can be mechanically entangled with the outer layer 26.

[0095] The outer layer 26 can be positioned between at least a portion of the tubular member 12 and the polymer matrix 200. For example, the silicone or other suitable polymeric material of the outer layer 26 can be disposed within at least a portion of the multiple openings 23 located between the multiple struts 22, and the multiple fibers 202 can be deposited over the multiple struts 22 and / or the multiple openings 23. To minimize the constraint on the flexibility of the tubular member 12, during the electrospinning process of the polymer matrix 200, the multiple fibers 202 can be concentrated over the multiple struts 22. Additionally, during the electrospinning process, the multiple fibers 202 can be selectively guided over the multiple struts 22 to maintain the profile of the multiple openings 23 defined therebetween. In the case where the polymer matrix 200 is formed along the exterior of the tubular member 12, the polymer matrix 200 can provide and maintain a barrier around the lumen of the tubular member 12. As described in detail herein, the polymer matrix 200 can provide a fixation mechanism for securing the stent 10 to a target treatment site within a subject's body. Additionally, the polymer matrix 200 can promote tissue ingrowth to facilitate anastomosis formation between two non-adherent tissues / structures.

[0096] The stent 10 may further include an optional bioadhesive coating 206 disposed over and at least partially covering the polymeric matrix 200. The bioadhesive coating 206 may be chemically bonded to the polymeric matrix 200. Thus, the polymeric 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 polymeric matrix 200. The bioadhesive coating 206 may include a biodegradable material such that the bioadhesive coating 206 may be 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 amount 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 from about 24 hours to about 6 months, such as from about 3 days to about 1 week, from about 1 week to about 6 weeks, from about 1 month to about 3 months, or from about 2 months to about 5 months. The degradation time may 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 over the polymeric matrix 200 may range from about at least 1 μm to at least 1 mm, such as, for example, 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. Additionally, the bioadhesive coating 206 may be chemically modified on the outer surface of the polymeric matrix 200.

[0097] Exemplary materials suitable for the bioadhesive coating 206 can include, but are not limited to, polysaccharides such as chitosan. The polysaccharides can be crosslinked with linker molecules. Such linker molecules include, for example, polyethylene glycol (PEG). In some cases, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) can be added to bind chitosan and PEG. The PEG can provide a hydrophilic backbone along the polymer matrix 200 and can serve as an anchor for the bioadhesive coating 206 to attach to the polymer matrix 200. The hydrophilic nature of the PEG can provide the adhesive ability to fix the bioadhesive coating 206 to the polymer matrix 200. Other suitable materials for the bioadhesive coating 206 can include, but are not limited to, polymers such as chitosan optionally modified with thiol groups, PEG modified with thiol groups, and oxidized cellulose. The bioadhesive coating 206 can have hemostatic properties for promoting a healing response originating from a target treatment site (e.g., tissue) when in contact with the target treatment site. In other words, the bioadhesive coating 206 can treat injuries at the target treatment site such as wounds, bleeding, damaged tissue, hemorrhage, etc. The bioadhesive coating 206 can be used as a wound dressing to inhibit excessive bleeding and / or promote rapid healing. Additionally, the bioadhesive coating 206 can have adhesive properties capable of fixing the tubular member 12 to the target treatment site in the body. For example, in some cases, the bioadhesive coating 206 can have a positive charge complementary to the negative charge of the mucus layer of the body. In some cases, the bioadhesive coating 206 can be dried, which can further increase the attraction between the bioadhesive coating 206 and the hydrated mucus layer.

[0098] As mentioned 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 be crosslinked with the plurality of fibers 202 to facilitate the connection between the bioadhesive coating 206 and the polymer matrix 200. In some instances, when the plurality of fibers 202 are formed on the tubular member 12, the linker molecules can become entangled with the polymer chains of the polymer matrix 200. In some examples, plasma can be used to crosslink the polysaccharides and the linker molecules to prepare the bioadhesive coating 206. The bioadhesive coating 206 can provide a temporary fixation mechanism for fixing the stent 10 to the target treatment site in a subject's body.

[0099] In accordance with some aspects of the present invention, multiple fibers 202 can be selectively deposited over the tubular member 12 to control the fixation characteristics of the stent 10 to the target treatment site and / or other characteristics of the stent 10. For example, multiple fibers 202 can be deposited along one or more regions of the tubular member 12, thereby controlling the tissue ingrowth into the stent 10 to one or more specific regions. As discussed above, the bioadhesive coating 206 can adhere to the surface region 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 102 when multiple fibers 202 are selectively deposited over one or more regions of the tubular member 12. In other examples, the thickness and / or deposition regions of the polymer matrix 200 and / or the bioadhesive coating 206 can be strategically placed to reduce bleeding and / or irritation at the implantation site. For example, in some embodiments, the first and / or second expansion regions 32, 34 can create bleeding and / or tissue irritation at the implantation site. It is contemplated that increasing the thickness of the polymer matrix 200 and / or the bioadhesive coating 206 at the first and / or second expansion regions 32, 34 can reduce the friction between the first and / or second expansion regions 32, 34 and the tissue, and thus reduce irritation to the tissue. It is contemplated that the thickness and / or position of the polymer matrix 200 and / or the bioadhesive coating 206 on the tubular member 12 can be customized for a particular implantation location.

[0100] Generally, the stent 10 can be positioned at the target treatment site by using a medical device (e.g., an endoscope, a catheter, etc.) that is inserted through the subject's body and navigated towards the target treatment site. It should be understood that the stent 10 can be used at various locations (target treatment sites) within the subject's body, including but not limited to the gastrointestinal tract, organs, or other tissues. Upon reaching the implantation location, the stent 10 can be inserted through the medical device and deployed from it at the target location. In some embodiments, if so configured, the bioadhesive coating 206 can provide a smooth outer non-damaging surface to facilitate passage of the stent 10 through the subject and / or inhibit damage to the target location caused by the polymer matrix 200 and / or the tubular member 12.

[0101] The stent 10 can be pressed against a target location such that the bioadhesive coating 206 contacts the mucus layer or other tissue membrane 14. In the case where the tubular member 12 has a flexible form, the stent 10 can conform to the contour of the target location. Additionally, in the case where the bioadhesive coating 206 is positively charged and the mucus layer or other tissue membrane is negatively charged, the bioadhesive coating 206 can be attracted to the mucus layer and form chemical bonds with the tissue surface, thereby anchoring the stent 10 to the target location. The bioadhesive coating 206 can maintain the stent against the target location for at least a minimum duration until the bioadhesive coating 206 is resorbed or otherwise degraded. Thus, the bioadhesive coating 206 can serve as a tissue adhesion mechanism to temporarily fix the stent 10 to the target location and inhibit migration of the stent 10 from the target treatment site. Additionally, the bioadhesive coating 206 can further promote healing at the target location via the hemostatic properties of the bioadhesive coating 206 while the bioadhesive coating 206 remains in contact with the target location.

[0102] When the bioadhesive coating 206 adheres the stent 10 to the target location, the bioadhesive coating 206 can promote tissue growth from the tissue wall through the polymer matrix 200. In other words, by maintaining the polymer matrix 200 in close proximity to the tissue wall, the bioadhesive coating 206 can allow tissue cells to grow from the tissue wall through the bioadhesive coating 206 and into the plurality of compartments 204. The tissue cells may become entangled with the plurality of fibers 202, thereby anchoring the stent 100 to the tissue wall and inhibiting migration of the stent from the target treatment site. In other words, the plurality of small holes 204 can serve as sites that allow tissue growth into the polymer matrix 200. The bioadhesive coating 206 can maintain the stent 10 against the tissue wall via bonding with the mucus layer or other tissue membrane, thereby allowing tissue cells sufficient time to grow through the polymer matrix 200.

[0103] As further described above, the size of the plurality of small holes 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 small holes 204. Additionally, the diameter of the plurality of fibers 202 can correspond to or be associated with the minimum force required to dislodge the stent 10 from the target treatment site. In other words, the size and / or shape of the plurality of fibers 202 can be set to provide the stent with sufficient mechanical strength to inhibit migration of the stent 10 from the target treatment site. For example, the minimum pull-out force sufficient to move the stent 10 relative to the target treatment site can be at least partially associated with the size and / or shape of the plurality of fibers 202. Thus, the diameter of the plurality of fibers 202 can be at least partially contributory to inhibiting inadvertent release of the stent 10 from the target tissue.

[0104] When the bioadhesive coating 206 degrades, the stent 10 can remain anchored to the tissue wall via the engagement of the polymeric matrix 200 with the target tissue (e.g., ingrowth of tissue into the polymeric matrix 200). Thus, even though the bioadhesive coating 206 is removed from between the polymeric matrix 200 and the tissue wall 12, the polymeric matrix 200 and the tubular member 12 can remain attached to the target tissue in response to the growth of tissue cells through the polymeric matrix 200. By providing a physical barrier between the tubular member 12 and the target tissue, the polymeric matrix 200 can ensure that a fluid path through the tubular member 12 is retained. In addition, the polymeric matrix 200 can facilitate the removal of the stent 10 upon completion of the procedure. For example, the polymeric 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 to the subject. In addition, for example, the thickness of the stent 10, including the exposed portions of the polymeric matrix 200 and the plurality of fibers 202, can facilitate the removal of the stent 10 from the subject. Additionally, the polymeric matrix 200 can control the extent (e.g., depth) and / or degree of tissue ingrowth into the stent, thereby providing further control for the removal of the stent 10 upon completion of the procedure. For example, as described above, in some cases, an inner layer of the polymeric matrix 210 can be provided to limit the depth of tissue ingrowth.

[0105] In some embodiments, alternative materials can be used in place of the bioadhesive coating with or without the polymeric matrix 200. Figure 12 FIG. 5 is an enlarged cross-sectional view of a portion of an illustrative stent 10 having an alternative coating 220. While the stent 10 is shown as including an inner layer 24, an outer layer 26, and the polymeric matrix 200, it is contemplated that any one, any two, or all of these layers can be omitted. In some cases, the alternative coating 220 can be a hydrogel adhesion layer. Some illustrative hydrogels can include, but are not limited to, gelatin, methacrylated gelatin (GelMA), polyethylene glycol (PEG)-based bioadhesives, chitosan, and / or derivatives thereof. It is contemplated that the hydrogel adhesion layer can reduce the foreign body response. In some cases, the hydrogel can be attracted to the mucosal layer (or other body tissue) to facilitate attachment of the stent 10 at the target location and limit migration of the stent 10 after implantation. In some cases, the hydrogel can be configured to maintain the stent 10 in the implanted position for a desired period of time. For example, the hydrogel can be configured to maintain the stent 10 in the desired position until tissue ingrowth has penetrated the struts 22 and / or the polymeric matrix 200, if provided.

[0106] In another example, the alternative coating 220 can be a filler hemostatic agent. Some illustrative hemostatic agents can include, but are not limited to, kaolin and sodium montmorillonite (MMT). The hemostatic agent can have some bioadhesiveness, which allows the hemostatic agent to adhere to body tissue at least temporarily after implantation. In some cases, the hemostatic agent can be configured to maintain the stent 10 in the implanted position for a desired period of time. For example, the hemostatic agent can be configured to maintain the stent 10 in the desired position until tissue ingrowth has penetrated the struts 22 and / or the polymer matrix 200, if provided. In some examples, the hemostatic agent can be provided as a coating that is disposed over the polymer matrix 200, as Figure 12 shown. In other examples, the hemostatic agent can 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 can form the outermost layer of the stent 10.

[0107] Figure 13 is a side view of another illustrative outer mesh or fabric sleeve 300 for use with a stent, such as the stent 10 described herein. In some cases, the outer mesh or fabric sleeve 300 can be formed from an elongate tubular member 302. Although the outer mesh or fabric sleeve 300 is described as being generally tubular, it is contemplated that the outer mesh or fabric sleeve 300 can assume any desired cross-sectional shape. For example, the outer mesh or fabric sleeve 300 can be shaped to fit over or conform to the shape of one or more portions of the stent 10, including the flanges 32, 34. The outer mesh or fabric sleeve 300 can be configured to extend over the entire length of the stent 10 or only over a portion of its length. For example, in some cases, the outer mesh or fabric sleeve 300 can extend along the body 18 of the stent 10 rather than over the flanges 32, 34. Thus, the entire length of the outer mesh or fabric sleeve 300 can be positioned between the flanges 32, 34. In some cases, the outer mesh or fabric sleeve 300 can be provided as two or more discrete components, where each of the two or more discrete components is configured to be positioned over a different portion of the stent 10, with some, little, or no overlap between the discrete components. In some cases, the outer mesh or fabric sleeve 300 can be fixedly coupled to the stent 10. In other cases, the outer mesh or fabric sleeve 300 can be positioned over the stent 10 but not coupled to the stent 10. For example, the outer mesh or fabric sleeve 300 can float over the outer surface of the stent 10 such that the outer mesh or fabric sleeve 300 can move axially and / or circumferentially relative to the stent 10.

[0108] The outer mesh or fabric sleeve 300 may 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 fabric sleeve 300 may include a lumen 310 that extends from a first opening adjacent the first end 304 to a second opening adjacent the second end 306 to permit the outer mesh or fabric sleeve 300 to be positioned over the stent 10.

[0109] The outer mesh or fabric sleeve 300 may be expanded from a first radially collapsed configuration (not explicitly shown) to a second radially expanded configuration by the expansion of the stent 10. In some cases, the outer mesh or fabric sleeve 300 may be deployed to a configuration between the collapsed configuration and the fully expanded configuration.

[0110] The outer mesh or fabric sleeve 300 may have an interlaced (e.g., knitted) structure made of a single filament 312 that interlaces with itself and defines open cells 314 or multiple filaments that interlace (e.g., are woven) with each other. In some cases, the filament 312 may be a monofilament, while in other cases, the filament 312 may be two or more filaments that are twisted, braided, or woven together. Although the illustrated embodiment shows a twisted knit stitch, it is contemplated that the outer mesh or fabric sleeve 300 may be formed using any desired stitch. Additionally, the outer mesh or fabric sleeve 300 may be formed using other techniques, including but not limited to weaving or winding. When the stent 10 is positioned at a target site within the body, the multiple open cells 314 may permit tissue to grow inwardly around the filaments 312. It is contemplated that the amount of tissue ingrowth may be controlled by the tightness of the knitted fabric. For example, the outer mesh or fabric sleeve 300 may be formed such that the open cells 312 are very small (e.g., adjacent portions of the filaments 314 contact or nearly contact each other). In other examples, the outer mesh or fabric sleeve 300 may be formed with a looser knitted fabric such that adjacent portions of the filaments 314 are spaced apart from each other to form larger pores 314. The larger the pores 314, the more tissue ingrowth may occur. Sufficient tissue ingrowth into and along the outer mesh or fabric sleeve 300 may form a tissue conduit connecting two separate anatomical structures, thereby forming an anastomosis therebetween. In some cases, once tissue ingrowth within the outer mesh or fabric sleeve 300 has sufficiently formed a tissue conduit between the anatomical structures, the stent 10 may be removed, leaving the outer mesh or fabric sleeve 300 in place at the formed anastomosis.

[0111] It is contemplated that the outer mesh or fabric sleeve 300 can be made of a variety of different materials, such as but not limited to synthetic or bioabsorbable textile materials. Some illustrative synthetic textile materials can include but are not limited to, polyamides, polyesters, polyethylene terephthalate (PTFE), expanded PTFE, polypropylene (PP), etc. Some illustrative bioabsorbable textile materials can 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.

[0112] It is contemplated that the inner or outer layers 24, 26, coatings / layers 36, 38, 40, 40', 40'', 40''', 40'''', 40''''', polymer matrices 200, 210, bioadhesive coatings 206, alternative outer coatings 220, and / or outer mesh or fabric sleeve 300 can be disposed over all or selected portions of the stent 10. In some cases, the position and / or thickness of the inner or outer layers 24, 26, coatings 36, 38, 40, 40', 40'', 40''', 40'''', 40''''', polymer matrices 200, 210, bioadhesive coatings 206, alternative outer coatings 220, and / or outer mesh or fabric sleeve 300 can be positioned to reduce bleeding and / or tissue irritation. In some cases, the inner or outer layers 24, 26, coatings 36, 38, 40, 40', 40'', 40''', 40'''', 40''''', polymer matrices 200, 210, bioadhesive coatings 206, alternative outer coatings 220, and / or outer mesh or fabric sleeve 300 can be thicker at areas of the stent 10 that are more likely to cause bleeding and / or tissue irritation upon implantation in the body, including but not limited to the flanges 32, 34. It is also contemplated that the inner or outer layers 24, 26, coatings 36, 38, 40, 40', 40'', 40''', 40'''', 40''''', polymer matrices 200, 210, bioadhesive coatings 206, alternative outer coatings 220, and / or outer mesh or fabric sleeve 300 can be applied as multiple layers. The multiple layers can vary to achieve the desired coating thickness.

[0113] It should be understood that the present invention is merely illustrative in many respects. Changes can be made in details, particularly in matters of the shape, size, and arrangement of steps, without exceeding the scope of the invention. To the appropriate extent, this can include using any of the features of one exemplary embodiment in other embodiments. Of course, the scope of the invention is defined by the language of the appended claims.

Claims

1. A stent, comprising: An elongate tubular body having a framework forming a plurality of compartments; And A coating disposed on an outer surface of the elongate tubular body, the coating comprising: A first microporous layer; And A macroporous layer disposed on the microporous layer.

2. The stent according to claim 1, wherein the macroporous layer comprises columnar structures.

3. The stent according to claim 1, wherein the macroporous layer comprises a plurality of rings.

4. The stent according to claim 3, wherein the plurality of rings are stacked one on top of another to form a plurality of columns.

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

6. The stent according to any one of claims 4 to 5, wherein at least some of the plurality of columns have a longitudinal axis that extends at an oblique angle to a longitudinal axis of the elongate tubular body.

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

8. The stent according to any one of claims 4 to 7, wherein at least some of the plurality of columns have free ends that are oriented towards a centrally longitudinally positioned column.

9. The stent according to any one of claims 4 to 8, wherein the density of the plurality of columns increases towards a centrally longitudinally positioned column.

10. The stent according to claim 3, wherein one of the plurality of rings is at least partially laterally spaced apart from a previous ring.

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

12. A stent, comprising: An elongate tubular body having a framework forming a plurality of compartments and a covering extending over the plurality of compartments of the framework; A fabric sleeve disposed on at least a portion of the elongate tubular body; Wherein the fabric sleeve is made of one or more interwoven filaments defining the plurality of open compartments.

13. The stent according to claim 12, wherein an entire length of the fabric sleeve is positioned between a first flange adjacent a first end of the elongate tubular body and a second flange proximal to a second end of the elongate tubular body.

14. The stent according to claim 12 or 13, wherein the fabric sleeve is removably disposed on the elongate tubular body.

15. The stent according to any one of claims 12 to 14, wherein the fabric sleeve is formed of a bioabsorbable textile material.

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