Anti-migration stent

Abstract

Stents, auxiliary compression structures for stents, and techniques to avoid migration of deployed stents are provided. An auxiliary support structure may be provided to apply a compressive force to the flange of the stent to further compress the stent or provide axial or radial support to the flange. The auxiliary support structure may be integrated into the stent or provided as a separate device.

Description

Cross - Reference to Related Applications

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 437,499, filed on January 6, 2023, the disclosure of which is incorporated herein by reference. Technical Field

[0002] The present disclosure generally relates to the field of implantable medical devices, and related systems and methods for regulating access through the channels of a medical device. More specifically, the present disclosure relates to devices, systems, and methods for bridging two anatomical structures, such as lumen apposition devices. Background Art

[0003] Treatment methods for various medical conditions, such as obesity, diabetes, pancreatic pseudocysts, biliary obstruction, and duodenal ulcers, involve creating an anastomosis between the stomach or duodenum and other structures, such as a pancreatic fluid accumulation area, gallbladder, bile duct, or jejunum. A lumen apposition device can be placed between the stomach or duodenum and another organ to allow materials (fluids, liquids, chyme, food, etc.) to pass between them. One challenge presented by such devices is preventing the device from migrating distally into another organ or proximally into the stomach or duodenum. Accordingly, there has been a continuing need to provide alternative medical devices and alternative methods for manufacturing and using medical devices. Summary of the Invention

[0004] The present disclosure provides alternatives in the design, materials, manufacturing methods, and uses of medical devices. One embodiment includes a system that includes a radially expandable tubular stent having a first end region, a second end region, an intermediate region located between the first end region and the second end region, and a lumen extending from the first end region to the second end region, wherein the first end region includes a first flange, the second end region includes a second flange, and an auxiliary support structure configured to provide support to the first flange and the second flange when the stent is in an expanded state.

[0005] Further embodiments may include the above system, wherein the first flange and the second flange are configured to engage body tissue without trauma.

[0006] Further embodiments may include the above system, wherein the auxiliary support structure includes a second radially expandable tubular stent having a first end region, a second end region, an intermediate region located between the first end region and the second end region, and a lumen extending from the first end region to the second end region, wherein the first end region of the second radially expandable tubular stent includes a first flange, and the second end region of the second radially expandable tubular stent includes a second flange.

[0007] Further embodiments may include the above-described system, wherein the first and second flanges of the first radially expandable tubular stent have a first diameter, and the first and second flanges of the second radially expandable tubular stent have a second diameter that is less than or equal to the first diameter.

[0008] Further embodiments may include the above-described system, wherein the first radially expandable tubular stent has a first longitudinal compression force, and the second radially expandable tubular stent has a second longitudinal compression force that is greater than the first longitudinal compression force.

[0009] Further embodiments may include the above-described system, wherein the auxiliary support structure includes a proximal flange retaining member, a distal flange retaining member, and a spring coupled between the proximal and distal flange retaining members.

[0010] Further embodiments may include the above-described system, wherein the first and second flanges of the radially expandable tubular stent have a first diameter, and wherein the proximal and distal flange retaining members include a second diameter that is greater than or equal to the first diameter minus 5 millimeters (mm) and less than or equal to the first diameter plus 5 mm.

[0011] Further embodiments may include the above-described system, wherein the unstretched length of the spring is less than or equal to the shortened length of the stent.

[0012] Further embodiments may include the above-described system, wherein the auxiliary support structure includes at least one spring integrally coupled to the first and second flanges, the at least one spring being biased to apply a compressive force to the flanges when the stent is in the shortened state.

[0013] Further embodiments may include the above-described system, wherein the spring includes a corrugation or fold that is biased to apply a compressive force to the first and second flanges.

[0014] Further embodiments may include the above-described system, wherein the spring includes a coil.

[0015] Further embodiments may include the above-described system, wherein the auxiliary support structure applies a compressive force to the stent, thereby reducing the longitudinal length of the stent and increasing or maintaining the radial diameter of the first and second flanges.

[0016] Further embodiments may include the above-described system, wherein the stent includes a coating.

[0017] Further embodiments may include the above-described system, wherein the stent and / or the auxiliary support structure includes nitinol.

[0018] Further embodiments may include the above-described system, wherein the radially expandable tubular stent includes a coating applied to the radially expandable tubular stent.

[0019] Another embodiment includes a stent comprising: a radially expandable tubular stent having a first end region, a second end region, an intermediate region between the first and second end regions, and a lumen extending from the first end region to the second end region, wherein the first end region includes a first flange, the second end region includes a second flange, and at least one spring integrally coupled to the first and second flanges, the at least one spring being biased to apply a compressive force to the flanges when the stent is in a shortened state.

[0020] A further embodiment may include the above stent, wherein the spring includes a crinkle or fold biased to apply a compressive force to the first and second flanges.

[0021] A further embodiment may include the above stent, wherein the spring includes a coil.

[0022] A further embodiment may include the above stent, wherein an auxiliary support structure applies a compressive force to the stent, thereby reducing the longitudinal length of the stent and increasing or maintaining the radial diameter of the first and second flanges.

[0023] A further embodiment may include the above stent, wherein the stent includes a coating.

[0024] A further embodiment may include the above stent, wherein the stent and / or the auxiliary support structure includes nitinol.

[0025] A further embodiment may include the above stent, wherein the radially expandable tubular stent includes a coating applied to the radially expandable tubular stent.

[0026] Another embodiment may include a method comprising: forming an anastomosis in tissue; deploying a radially expandable tubular stent into the anastomosis, the radially expandable tubular stent having a first end region, a second end region, an intermediate region between the first and second end regions, and a lumen extending from the first end region to the second end region, wherein the first end region includes a first flange and the second end region includes a second flange; and deploying an auxiliary support structure around the deployed radially expandable tubular stent.

[0027] A further embodiment may include, wherein the auxiliary support structure includes a second radially expandable tubular stent having a first end region, a second end region, an intermediate region between the first and second end regions, and a lumen extending from the first end region to the second end region, and wherein the first end region of the second radially expandable tubular stent includes a first flange and the second end region of the second radially expandable tubular stent includes a second flange.

[0028] Further embodiments may include, wherein the first and second flanges of the first radially expandable tubular stent have a first diameter, and the first and second flanges of the second radially expandable tubular stent have a second diameter that is less than or equal to the first diameter.

[0029] Further embodiments may include, wherein the first radially expandable tubular stent has a first longitudinal compression force, and the second radially expandable tubular stent has a second longitudinal compression force that is greater than the first longitudinal compression force.

[0030] Further embodiments may include, wherein the auxiliary support structure includes a proximal flange retaining member, a distal flange retaining member, and a spring coupled between the proximal and distal flange retaining members.

[0031] The foregoing summary of some embodiments is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The following disclosure more specifically illustrates these embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present disclosure may be more fully understood when the following detailed description is considered in conjunction with the accompanying drawings, in which:

[0033] Figure 1 A perspective view of a stent located between a portion of the stomach and the small intestine is shown;

[0034] Figure 2 A cross-sectional view of a stent located between a portion of the stomach and the small intestine taken along line 2-2 is shown; Figure 1

[0035] Figure 3A And Figure 3B An embodiment of a stent is shown;

[0036] Figure 4 An embodiment of a stent flange retaining member is shown.

[0037] Figure 5 An embodiment of another stent flange retaining member is shown;

[0038] Figure 6 A stent delivery device is shown;

[0039] Figure 7 A deployed stent with a retaining member is shown;

[0040] Figure 8A And Figure 8B A stent and a stent deployment device are shown;

[0041] Figure 9A And Figure 9B A stent and a retaining member are shown; ​

[0042] Figure 10 shows an auxiliary compression support structure for a stent;

[0043] Figure 11A , Figure 11B and Figure 11C shows an auxiliary compression support structure for a stent in various deployment states; and

[0044] Figure 12 shows a stent deployed on top of another stent.

[0045] Although the present disclosure may be subject to various modifications and alternative forms, specific examples thereof have been shown in the drawings and will be described in detail. However, it should be understood that the intention is not to limit the invention to the described embodiments. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit of the present disclosure. Detailed Description

[0046] For the terms defined below, these definitions shall apply unless a different definition is given in the claims or elsewhere in this specification.

[0047] 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 skilled 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 include numbers rounded to the nearest significant figure.

[0048] The recitation of a numerical range defined 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).

[0049] As used in this specification and the appended claims, the singular forms "a" 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 used in its inclusive sense of "and / or" unless the context clearly dictates otherwise.

[0050] It should be noted that references in this specification to "one embodiment", "some embodiments", "other embodiments", etc., indicate that the described embodiments may include one or more features, structures, and / or characteristics. However, such references do not necessarily mean that all embodiments include the recited features, structures, and / or characteristics. Furthermore, when a feature, structure, and / or characteristic is described in connection with one embodiment, such feature, structure, and / or characteristic may also be used in connection with other embodiments whether or not explicitly described, unless clearly stated to the contrary.

[0051] According to various principles of the present disclosure, an implantable device can be used to extend through an anatomical structure to control or adjust the size of a passage therethrough. For example, an implantable device can extend through a body passage or lumen, and these terms are used interchangeably herein without any intention to limit it. A body passage or lumen can include, but is not limited to, a portion of a passage or lumen, a passage or lumen between anatomical structures (a passage, a lumen, a cavity, an organ, etc.), a passage formed through an attached tissue wall (e.g., to create an anastomosis), etc. The device has a passage or lumen therethrough (these terms are used interchangeably herein without any intention to limit it), which can be used to allow material (e.g., fluid, liquid, chyme, food, etc.) to pass between anatomical structures in which an anastomosis is formed and in which the device is located. Therefore, the device can be considered and referred to as an occlusion device, a lumen attachment device, or an anastomotic device, or a flow facilitating device, or a flow regulating device, or a flow control device, and these terms and various other alternative terms can be used interchangeably herein without any intention to limit it.

[0052] The following detailed description should be read in conjunction with the accompanying drawings, in which similar elements in different drawings are numbered the same. The drawings are not necessarily drawn to scale, depict illustrative embodiments, and are not intended to limit the scope of the invention.

[0053] Figure 1 A perspective view of an exemplary stent 10 is shown positioned between the stomach 20 and the jejunum 30 (a portion of the small intestine), and Figure 2 Shown along Figure 1 2-2 is a cross-sectional view of the stent 10 positioned between the stomach 20 and the jejunum 30. The stomach 20 typically passes food material (e.g., chyme, partially digested food material, fluids, etc.) into the duodenum 40 through the pylorus 60. In some cases, treatment for a patient with obesity, diabetes, or duodenal ulcers may involve bypassing the duodenum 40 or restricting the flow of material through the duodenum 40. If treatment requires completely bypassing the duodenum 40, then blocking the pylorus 60 (e.g., complete blocking) may be indicated, and a stoma (anastomosis) 15 may be created between the stomach 20 and the jejunum 30, which may be referred to as a gastrojejunostomy. Figure 1 An exemplary bypass procedure is shown in which a flow restrictor 50 has been placed within the pylorus 60 to restrict the passage of food material from the stomach 20 to the duodenum 40 (e.g., complete bypass). A lumen-attached metal stent (LAMS), such as stent 10, can be placed between the stomach 20 and the jejunum 30 to form an anastomosis 15 to allow food material (fluid, liquid, chyme, etc.) to pass from the stomach 20 through the lumen 11 of the stent 10 into the jejunum 30, as shown. Figure 1 and Figure 2 shown.

[0054] The stent 10 is held in place by flanges 12 provided on both the proximal and distal ends of the stent 10. The flanges 12 are provided at both ends of an intermediate region 13, the radial diameter of which is smaller than the radial diameter of the flanges 12. The flanges 12 and the intermediate region 13 are configured to engage the tissue surface 14 of both the stomach 20 and the jejunum 30 and apply a radial force and a compressive force to the tissue 14 to help hold the stent 10 in the anastomosis 15.

[0055] Although the stent 10 is shown as being useful for forming an anastomosis 15 between the stomach 20 and the jejunum 30, it is contemplated that the stent 10 can be used to drain a pancreatic fluid accumulation area, a pancreatic duct, a bile duct, or a gallbladder into the stomach or duodenum, for treating stenosis in a blood vessel, for maintaining a fluid opening or path in a blood vessel, urinary, biliary, tracheobronchial, esophageal, or renal tract, or for placing a device such as an artificial valve or filter at an internal body cavity location, in some cases. Although shown as a stent, the stent 10 can be any of several devices that can be introduced endoscopically, subcutaneously, percutaneously, or surgically to be positioned within an organ, tissue, or lumen, such as the heart, artery, vein, urethra, esophagus, trachea, bronchus, bile duct, pancreatic duct, pancreatic fluid accumulation area, gallbladder, etc.

[0056] Once a lumen-apposing stent is placed, it is crucial that it remains in place to hold the two lumens together and bridge the openings in their walls. If it migrates out of position, the contents of the lumens may leak into the peritoneal cavity. If partially digested food leaks from the stomach, or digestive fluid leaks from the bile duct or pancreatic duct, or infected necrotic tissue leaks from the pancreatic fluid accumulation area and enters the abdomen, this would pose a significant risk to the patient's health. The present disclosure provides methods, techniques, devices, and systems that allow a physician to prevent the migration of a lumen-apposing stent.

[0057] The present disclosure provides a device that prevents the migration of a lumen-apposing stent, and / or a device that anchors two tissue planes and / or a stent together to prevent the distal tissue from moving away from the proximal tissue during and / or after stent placement.

[0058] In some embodiments of the present disclosure, a flange retaining member is integrally provided within the stent 10 and is biased to apply a compressive force to the tissue 14 of the anastomosis 15. As noted, the stents described herein can be used during several procedures, for example, when creating an anastomosis for gallbladder drainage.

[0059] Figure 3A and Figure 3BIllustrated is a stent 310 including a flange retaining member 316. The flange retaining member 316 includes a retaining member end 318 configured to engage a flange 312 of the stent 310. In some embodiments, the retaining member end 318 can be a hook, arrow, or other mechanism or shape arranged to engage and / or mechanically couple to the structure of the stent 310. As a specific example, the retaining member end 318 can be hook-shaped and can be configured to engage and / or mechanically couple to a portion of a wire mesh on both the distal and proximal flanges 312 of the stent 310. Additionally, as shown, a pair of flange retaining members 316 are provided and integrally formed to couple to and apply a compressive force to each pair of distal and proximal flanges 312.

[0060] The flange retaining member 316 can be made of nitinol and can include various shapes or designs, for example, see Figure 4 and Figure 5 . Generally, the flange retaining member 316 can be packaged integrally with the stent 310 and the delivery device. Various stent delivery devices are known in the art. For example, a common stent delivery device holds the stent 310 in a compressed and expanded state within a delivery sheath 302. The delivery sheath 302 is configured to be delivered to an anastomosis site via an endoscope. During delivery, the stent 310 is held by the sheath 302 in an expanded and flattened state, as Figure 3A shown. However, once deployed, the flange retaining member 316 is biased to apply pressure in the direction of arrow 350 to pull the flange 312 towards the tissue 14 of the anatomical structure forming the anastomosis (e.g., the stomach 20 and jejunum 30, etc.).

[0061] It is important to note that although only two flange retaining members 316 are shown herein, the stent 310 can be provided with more than 2 flange retaining members 316, for example, 3, 4, 5, 6, etc.

[0062] Figure 4 Illustrated is a flange retaining member 400 which, in some embodiments, can be implemented as the flange retaining member 316. The flange retaining member 400 includes a distal retaining member end 462 and a proximal retaining member end 464 and a central biasing region 466. The central biasing region 466 can include pleats or tubes that are folded or stacked on each other and is biased to return to a shortened length when released from the delivery device sheath 302. In other words, the central biasing region 466 can be arranged to be compressed into an expanded state and is biased to return to a shortened state. Thus, once deployed, the central biasing region 466 can cause the flange retaining member 400 to return to a shortened state, thereby applying pressure to the flange 312 in the direction of arrow 350.

[0063] Figure 5Shown is a flange retention member 500 which, in some embodiments, may be implemented as flange retention member 316. The flange retention member 500 includes a distal retention member end 562 and a proximal retention member end 564 and a central biasing region 566. The central biasing region 566 may include a spring. The spring may be arranged to be stretched into an extended state and biased to return to a shortened state. Thus, once deployed, the central biasing region 566 may cause the flange retention member 500 to return to the shortened state, thereby applying pressure to the flange 312 in the direction of arrow 350.

[0064] As noted, stents are commonly used to drain adherent structures (e.g., areas of pancreatic fluid accumulation, etc.). However, stents may also be used in non-adherent structures (e.g., the stomach, gallbladder, and jejunum). If the stent migrates or is removed prematurely, there is a risk of leakage, which can be catastrophic for the patient and require surgical intervention.

[0065] The present disclosure provides a stent including an additional member arranged to provide internal support to the stent. The additional member and the internal support may reduce the likelihood of stent collapse or migration.

[0066] Figure 6 Shown is a stent delivery device 600 having a handle 603 and a tip 601. The tip 601 may be configured to form an anastomosis 15, while the handle 603 may be configured to deploy a stent 610 into the anastomosis. A first flange (e.g., a more distal flange) is deployed distal to the anastomosis 15, and then a second flange (e.g., a more proximal flange) is deployed proximal to the anastomosis 15. As described above, the delivery device includes a sheath in which the stent is held in a compressed and extended position. The delivery device 600 includes a sheath 602 from which the stent 610 may be deployed. Additionally, the delivery device 600 includes a plastic pigtail stent 670 mounted above or distal to the sheath 602, and a pigtail stent pusher 604 arranged to deploy the pigtail stent inside the lumen of the stent 610 once the stent 610 is deployed (see Figure 7 ). The pigtail stent pusher 670 may be used to push the pigtail stent 670 of the sheath such that the pigtail stent 670 is deployed and its ends unfurl on both the proximal and distal sides of the stent 610.

[0067] The pigtail stent 670 is located within the lumen of the stent 610, and the two coiled ends of the stent provide an auxiliary means of holding the two lumens together. The pigtail stent may be hollow, allowing fluid flow and drainage, providing a backup in case the main lumen-attached stent 610 becomes blocked. In some embodiments, the delivery device 600 may be packaged to include both the stent 610 and the pigtail stent 670.

[0068] Figure 7An example of a deployed stent 610 and a pigtail stent 670 is shown. The outer diameter of the pigtail stent 670 can be smaller than the inner diameter of the stent 610. The length of the straight portion of the pigtail stent 670 and the length of the stent 610 can be similar such that they can both apply pressure to the lumen wall. It should be understood that the devices shown in this figure are not to scale and the dimensions of the pigtail stent 670 relative to the stent 610 can vary.

[0069] Figure 8A and Figure 8B A stent 810 and a delivery system 800 are shown, the delivery system including a sheath 802 in which the stent 810 is held in a compressed and expanded position and deployable from the sheath. The delivery system 800 includes a tip 801 for forming an anastomosis as described above. The stent 810 also includes flanges 812 and a flange support structure 880. The auxiliary support structure 880 can be a shaped wire, spring, or other structure that unfolds and provides support to the flange 812 when the stent 810 is deployed and the flange 812 is expanded to its expanded state. In some embodiments, one of the flanges can include the flange support structure 880. In other embodiments, both flanges 812 can include the flange support structure. In some embodiments, as an addition or alternative to providing an auxiliary support structure to the flange 812, an auxiliary support structure 880 can be provided to the intermediate region 813. Providing support to the flange helps prevent migration of the stent from the anastomosis.

[0070] In some embodiments, an auxiliary support structure 880 can be provided in either or both of the distal and proximal flanges 812 such that the intermediate (or central saddle) region 813 can remain flexible while the flanges 812 are more rigid. Thus, the radial and axial stiffness distributions of the flanges 812 can be decoupled from the intermediate region 813.

[0071] Figure 9A and Figure 9B An alternative to providing support to the flange is shown. Figure 9A and Figure 9B Alternative designs of stents 910 and 910' in an expanded state are shown respectively. As can be seen, the flanges 912 and the auxiliary support structure 980 have expanded, and the auxiliary support structure 980 provides radial and axial support to the expanded flanges 912.

[0072] As noted above, stents are typically placed between two non-adherent structures (e.g., as in gastrojejunostomy, hepatogastrostomy, drainage of the gallbladder to the stomach or duodenum, etc.). Once the anastomosis is completed, it is critical to ensure that the stent will be maintained in place. For example, a migrated stent can cause infectious material to leak into the peritoneal cavity, leading to infection or other complications, and may require surgical intervention to correct. The present disclosure provides auxiliary compression and / or expansion supports for stents. In particular, the auxiliary compression support structure can withstand some of the tension between the two non-adherent structures, thereby releasing some of the tension borne by the flange of the stent.

[0073] Figure 10 An auxiliary compression support structure 1000 is shown that can be provided and deployed within a stent. The auxiliary compression support structure 1000 includes proximal and distal flange retaining ends 1002, and a spring structure 1004 disposed between the retaining ends 1002. The auxiliary compression support structure 1000 can be formed of a metal or a shape memory alloy (e.g., Nitinol) and biased to return to a formed shape. Thus, the auxiliary compression support structure 1000 can be flattened into a delivery device (e.g., a catheter delivery tube, etc.) and delivered into the stent. The retaining end 1002 can be arranged (or shaped) to be mechanically coupled to the outer wall of the flange 12 of the stent 10. Thus, the spring 1004 will release some tension from the flange itself and increase the force of the stent 10.

[0074] Figure 11A 、 Figure 11B and Figure 11C Depicted is a diagram showing Figure 10 The auxiliary compression support structure 1000 is deployed into the deployed stent (e.g., Figure 2 First, turn to Figure 11A Once the stent 10 is deployed, the distal flange retaining end 1002 of the auxiliary compression support structure 1000 can be deployed (eg, using a catheter and deployment handle, etc.) onto the distal flange 12 of the stent 10 .

[0075] Steering Figure 11B , the proximal flange retaining end portion 1002 of the auxiliary compressive support structure 1000 can be deployed (e.g., using the same catheter and deployment handle) onto the proximal flange 12 of the stent 10. It should be understood that once both the distal and proximal flange retaining end portions 1002 of the auxiliary compressive support structure 1000 are deployed onto the respective distal and proximal flanges 12, tension will be released from the flange 12 of the stent 10, and further, the stent 10 will be compressed more than without the assistance of the auxiliary compressive support structure 1000. Consequently, the diameter of the flange 12 will increase. That is, due to the compressive support of the auxiliary compressive support structure 1000, the longitudinal length of the stent 10 will decrease, further causing the diameter of the flange 12 to increase.

[0076] Figure 11C An axial view of the stent 10 with an auxiliary compression support structure 1000 deployed therein is shown. Figure 11C The retaining end 1002 coupled to the flange 12 and the spring 1004 disposed within the lumen of the stent 10 are shown. In some embodiments, the size and shape of the retaining end can be customized for a particular flange diameter. Additionally, the spring 1004 can be customized to have a particular spring stiffness and an unbiased length for various stent lengths or procedures.

[0077] In another embodiment, the auxiliary compression support structure 1000 can be directly connected to the flange of the stent 10 during manufacture. Similar to the concept shown in FIG. 3, when compressed into the delivery catheter, it can assume an elongated position and, once the stent 10 is deployed, it assumes Figure 11B the shape shown in.

[0078] In some embodiments, the auxiliary compression support structure 1000 can be provided by another stent. For example, Figure 12 An inner stent 10a deployed in an anastomosis and an outer stent 10b deployed around the inner stent 10a are shown. In some embodiments, the inner stent 10a can be provided with a flange having a larger diameter than the outer stent 10b, while the outer stent 10b can be provided with a higher compression force. In this way, the diameter of the flange of the inner stent 10a can be increased as described above.

[0079] Generally, the stents described herein can have an expanded outer diameter in the range of 6 - 70 millimeters (mm), a shortened length (e.g., uncompressed length) in the range of 8 - 120 mm, and an intermediate segment diameter in the range of 5 - 30 mm. Additionally, the support structures described herein can have dimensions sized to mechanically couple to a deployed stent and provide the auxiliary support detailed herein.

[0080] In some embodiments, the devices described herein can be made of metal, metal alloy, polymer (some examples of which are disclosed below), metal - polymer composite, ceramic, combinations thereof, etc., or other suitable materials. Some examples of suitable polymers can include polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), polyoxymethylene (POM, e.g., obtained from DuPont ), polyether block ester, polyurethane (e.g., polyurethane 85A), polypropylene (PP), polyvinyl chloride (PVC), polyether - ester (e.g., obtained from DSM Engineering Plastics ), ether or ester - based copolymers (e.g., butene / poly(alkylene ether) phthalate and / or other polyester elastomers, such as obtained from DuPont ), polyamide (e.g., obtained from Bayer or obtained from Elf Atochem ), elastomeric polyamides, block polyamide / ethers, polyether block amides (PEBA, e.g., available under the trade name ), ethylene vinyl acetate copolymers (EVA), silicones, polyethylene (PE), high density polyethylene, low density polyethylene, linear low density polyethylene (e.g., ), polyesters, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polypropylene terephthalate, polyethylene naphthalate (PEN), polyether ether ketone (PEEK), polyimide (PI), polyetherimide (PEI), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), poly(p-phenylene terephthalamide) (e.g., ), polysulfone, nylon, nylon-12 (e.g., obtained from EMS-Grilon, USA ), perfluoro(propyl vinyl ether) (PFA), ethylene vinyl alcohol, polyolefins, polystyrene, epoxy resins, polyvinylidene chloride (PVdC), poly(styrene-b-isobutylene-b-styrene) (e.g., SIBS and / or SIBS 50A), polycarbonates, ionomers, biocompatible polymers, other suitable materials, or mixtures, combinations, copolymers, polymer / metal composites, etc. In some embodiments, the sheath may be blended with a liquid crystal polymer (LCP). For example, the mixture may contain up to about 6% LCP.

[0081] In at least some embodiments, part or all of the devices described herein may be doped with, made of, or otherwise include a radiopaque material. A radiopaque material is understood to be a material that can produce a relatively bright image on a fluoroscope or another imaging technique during a medical procedure. This relatively bright image helps the user determine the position of the device during the procedure. Some examples of radiopaque materials may include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloys, polymer materials loaded with radiopaque fillers, etc. Additionally, other radiopaque marker bands and / or coils may also be incorporated into the design of the device.

[0082] In some embodiments, the materials may be compatible with magnetic resonance imaging (MRI). Some materials that exhibit these properties include, for example, polymers, tungsten, cobalt-chromium-molybdenum alloys (e.g., UNS: R30003, such as ), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R30035, such as ), nitinol, platinum-iridium alloys, etc., and other materials.

[0083] It should be understood that the present disclosure is illustrative in many respects. Changes may be made in details, particularly in the arrangement of shapes, sizes, and steps, without departing from the scope of the present disclosure. This may include using any feature of one exemplary embodiment in other embodiments where appropriate. The scope of the invention is, of course, defined by the language expressed in the appended claims.

Claims

1. A system, comprising: a radially expandable tubular stent having a first end region, a second end region, an intermediate region between the first end region and the second end region, and a lumen extending from the first end region to the second end region, wherein the first end region includes a first flange and the second end region includes a second flange; and an auxiliary support structure configured to provide support to the first flange and the second flange when the stent is in an expanded state.

2. The system according to claim 1, wherein the first flange and the second flange are configured to non-invasively engage body tissue.

3. The system according to any one of claims 1 or 2, wherein the auxiliary support structure includes a second radially expandable tubular stent having a first end region, a second end region, an intermediate region between the first end region and the second end region, and a lumen extending from the first end region to the second end region, wherein the first end region of the second radially expandable tubular stent includes a first flange and the second end region of the second radially expandable tubular stent includes a second flange.

4. The system according to claim 3, wherein the first flange and the second flange of the first radially expandable tubular stent have a first diameter, and the first flange and the second flange of the second radially expandable tubular stent have a second diameter that is less than or equal to the first diameter.

5. The system according to claim 4, wherein the first radially expandable tubular stent has a first longitudinal compression force, and the second radially expandable tubular stent has a second longitudinal compression force that is greater than the first longitudinal compression force.

6. The system according to any one of claims 1 or 2, wherein the auxiliary support structure includes a proximal flange retaining member, a distal flange retaining member, and a spring connected between the proximal flange retaining member and the distal flange retaining member.

7. The system according to claim 6, wherein the first flange and the second flange of the radially expandable tubular stent have a first diameter, and the proximal flange retaining member and the distal flange retaining member have a second diameter that is greater than or equal to the first diameter minus 5 millimeters (mm) and less than or equal to the first diameter plus 5 mm.

8. The system according to claim 6, wherein the unstretched length of the spring is less than or equal to the shortened length of the stent.

9. The system according to any one of claims 1 or 2, wherein the auxiliary support structure includes at least one spring integrally connected to the first flange and the second flange, the at least one spring being biased to apply a compressive force to the flanges when the stent is in a shortened state.

10. The system according to claim 9, wherein the spring includes a pleat or a fold that is biased to apply a compressive force to the first flange and the second flange.

11. The system according to claim 9, wherein the spring includes a coil.

12. The system according to any one of claims 1 to 11, wherein the auxiliary support structure applies a compressive force to the stent to reduce the longitudinal length of the stent and increase or maintain the radial diameters of the first flange and the second flange.

13. The system according to any one of claims 1 to 12, wherein the stent comprises a coating.

14. The stent according to any one of claims 1 to 13, wherein the stent and / or the auxiliary support structure comprises nitinol.

15. The stent according to any one of claims 1 to 14, wherein the radially expandable tubular stent comprises a coating applied to the radially expandable tubular stent.

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