Anti-migration stent

Abstract

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

Description

[Technical Field]

[0001] The present disclosure relates generally to the field of implantable medical devices and related systems and methods for adjusting accessibility through a medical device passageway. More specifically, the present disclosure relates to devices, systems, and methods for bridging two anatomical structures, such as lumen apposition devices. [Background technology]

[0002] 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 collection, gallbladder, bile duct, or jejunum. Lumenal apposition devices may be placed between the stomach or duodenum and another organ to allow the passage of substances (fluids, liquids, chyme, food, etc.) therebetween. One challenge presented by such devices is preventing migration of the device distally into the other organ or proximally into the stomach or duodenum. Thus, there is a continuing need to provide alternative medical devices and alternative methods for manufacturing and using medical devices. Summary of the Invention

[0003] The present disclosure provides design, material, manufacturing method, and use alternatives for medical devices. One embodiment includes a system comprising: a radially expanding tubular framework having a first end region, a second end region, an intermediate region positioned between the first end region and the second end region, and a lumen extending from the first end region to the second end region, the first end region comprising a first flange and the second end region comprising a second flange; and a secondary support structure configured to provide support to the first flange and the second flange when the stent is in an expanded state.

[0004] Further embodiments may include the system described above, wherein the first flange and the second flange are configured to atraumatically engage body tissue. Further embodiments may include the above system, wherein the auxiliary support structure comprises a second radially expanding tubular framework having a first end region, a second end region, an intermediate region positioned 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 expanding tubular framework comprises a first flange and the second end region of the second radially expanding tubular framework comprises a second flange.

[0005] Further embodiments may include the above system, wherein the first and second flanges of the first radially expanding tubular framework have a first diameter, and the first and second flanges of the second radially expanding tubular framework have a second diameter that is less than or equal to the first diameter.

[0006] Further embodiments may include the above system, wherein the first radially expanding tubular framework has a first longitudinal compressive force and the second radially expanding tubular framework has a second longitudinal compressive force that is greater than the first longitudinal compressive force.

[0007] Further embodiments may include the above system, wherein the auxiliary support structure comprises a proximal flange retaining member, a distal flange retaining member, and a spring coupled between the proximal and distal flange retaining members.

[0008] Further embodiments may include the above system, wherein the first and second flanges of the radially expanding tubular framework have a first diameter, and the proximal and distal flange retaining members have a second diameter, the second diameter being equal to or greater than the first diameter minus 5 millimeters (mm) and equal to or less than the first diameter plus 5 mm.

[0009] Further embodiments may include the above system, wherein the spring has an unstretched length that is less than or equal to the shortened length of the stent. Further embodiments may include the above system, wherein the auxiliary support structure comprises at least one spring integrally coupled 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 the shortened state.

[0010] Further embodiments may include the above system, wherein the spring comprises pleats or folds biased to apply a compressive force to the first flange and the second flange. Further embodiments may include the above system, wherein the spring comprises a coil.

[0011] Further embodiments may include the above 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 flange and second flange.

[0012] Further embodiments may include the above system, wherein the stent comprises a coating. Further embodiments may include the above system, wherein the stent and / or the auxiliary support structure comprises nitinol.

[0013] Further embodiments may include the above system, wherein the radially expanding tubular framework includes a coating applied onto the radially expanding tubular framework.

[0014] Another embodiment includes a stent comprising: a radially expanding tubular framework having a first end region, a second end region, an intermediate region positioned between the first end region and the second end region, and a lumen extending from the first end region to the second end region, the first end region comprising a first flange and the second end region comprising a second flange; and at least one spring integrally coupled to the first flange and the second flange, the at least one spring being biased to apply a compressive force on the flanges when the stent is in a shortened state.

[0015] Further embodiments may include the stent described above, wherein the spring comprises pleats or folds biased to apply a compressive force to the first flange and the second flange. Further embodiments may include the stent described above, wherein the spring comprises a coil.

[0016] In a further embodiment, the auxiliary support structure may include a stent as described above that 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 flange and second flange.

[0017] Further embodiments may include the stent described above, wherein the stent comprises a coating. Further embodiments may include the stents described above, wherein the stent and / or the supporting support structure comprises nitinol.

[0018] Further embodiments may include the stent described above, wherein the radially expanding tubular framework includes a coating applied over the radially expanding tubular framework.

[0019] Another embodiment may include a method including forming an anastomosis in tissue; deploying a radially expanding tubular framework within the anastomosis, the radially expanding tubular framework comprising a first end region, a second end region, an intermediate region positioned between the first end region and the second end region, and a lumen extending from the first end region to the second end region, the first end region comprising a first flange and the second end region comprising a second flange; and deploying a supplemental support structure around the deployed radially expanding tubular framework.

[0020] Further embodiments may include the auxiliary support structure comprising a second radially expanding tubular framework having a first end region, a second end region, an intermediate region positioned 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 expanding tubular framework comprises a first flange and the second end region of the second radially expanding tubular framework comprises a second flange.

[0021] Further embodiments may include the first and second flanges of the first radially expanding tubular framework having a first diameter and the first and second flanges of the second radially expanding tubular framework having a second diameter less than or equal to the first diameter.

[0022] Further embodiments may include the first radially expanding tubular framework having a first longitudinal compressive force and the second radially expanding tubular framework having a second longitudinal compressive force greater than the first longitudinal compressive force.

[0023] Further embodiments may include the auxiliary support structure comprising a proximal flange retaining member, a distal flange retaining member, and a spring coupled between the proximal and distal flange retaining members.

[0024] The above summary of some embodiments is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The following disclosure more particularly exemplifies these embodiments.

[0025] The present disclosure may be more fully understood from the following detailed description considered in conjunction with the accompanying drawings, in which: [Brief explanation of the drawings]

[0026] [Figure 1] 1 shows a perspective view of a stent positioned between the stomach and a portion of the small intestine. [Figure 2] 2 shows a cross-sectional view of a stent positioned between the stomach and a portion of the small intestine at line 2-2 of FIG. 1. [Figure 3A] 1 illustrates an embodiment of a stent. [Figure 3B] 1 illustrates an embodiment of a stent. [Figure 4] 1 illustrates one embodiment of a stent flange retention member. [Figure 5] 10 illustrates an embodiment of an alternative stent flange retention member. [Figure 6] 1 shows a stent delivery device. [Figure 7] 1 shows a deployed stent with a retention member. [Figure 8A] 1 shows a stent and a stent deployment device. [Figure 8B] 1 shows a stent and a stent deployment device. [Figure 9A] 1 shows a stent and a retention member. [Figure 9B] 1 shows a stent and a retention member. [Figure 10] 1 shows an auxiliary compression support structure for a stent. [Figure 11A] 10A-10C show the stent and the auxiliary compression support structure for the stent in various states of deployment. [Figure 11B] 10A-10C show the stent and the auxiliary compression support structure for the stent in various states of deployment. [Figure 11C] 10A-10C show the stent and the auxiliary compression support structure for the stent in various states of deployment. [Figure 12] 1 shows a stent deployed over another stent. DETAILED DESCRIPTION OF THE INVENTION

[0027] While the present disclosure is susceptible to various modifications and alternative forms, specifics of which have been shown by way of example in the drawings and will be described in detail. It should be understood, however, 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 disclosure.

[0028] For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification. All numerical values ​​are assumed to be modified herein by the term "about," whether explicitly stated or not. The term "about" generally refers to a range of numbers that one of ordinary skill in the art would consider equivalent to the recited value (e.g., having the same function or result). In many instances, the term "about" may include numbers that are rounded to the nearest significant figure.

[0029] The recitation of numerical ranges by endpoints includes all numbers within that range (eg, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is used generally in its sense including "and / or" unless the content clearly dictates otherwise.

[0030] It should be noted that references herein to "embodiments," "some embodiments," "other embodiments," etc., indicate that the described embodiments may include one or more features, structures, and / or characteristics. However, such descriptions do not necessarily mean that all embodiments include the feature, structure, and / or characteristic. In addition, 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 expressly stated otherwise.

[0031] In accordance with various principles of the present disclosure, an implantable device may be used to extend across an anatomical structure to control or adjust the size of a passage therethrough. For example, the implantable device may extend across a body passageway or lumen (such terms are used synonymously herein and without limitation). A body passageway or lumen may include, but is not limited to, a portion of a passageway or lumen, a passageway or lumen between anatomical structures (passageways, lumens, cavities, organs, etc.), a passageway formed across apposing tissue walls (such as to form an anastomosis), etc. The device has a passageway or lumen (such terms are used synonymously herein and without limitation) therethrough that may be used to form an anastomosis and allow the passage of substances (e.g., fluids, liquids, chyme, food, etc.) between anatomical structures in which the device is positioned. Thus, the device may be considered and referred to as an occlusion device or a lumen apposition device or an anastomosis device or a flow enabling device or a flow regulating device or a flow control device, and such terms and various other alternatives thereof may be used interchangeably herein without any limitation intended.

[0032] The following detailed description should be read with reference to the drawings, in which like elements in different drawings are numbered the same. The drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the invention.

[0033] FIG. 1 shows a perspective view of an exemplary stent 10 positioned between a stomach 20 and a jejunum 30 (a portion of the small intestine), and FIG. 2 shows a cross-sectional view of the stent 10 positioned between the stomach 20 and the jejunum 30 along line 2-2 in FIG. 1. The stomach 20 normally allows food material (e.g., chyme, partially digested food material, fluid, etc.) to pass through the pylorus 60 into the duodenum 40. In some cases, treatment for patients experiencing obesity, diabetes, or duodenal ulcers may include bypassing the duodenum 40 or restricting the flow of material through the duodenum 40. If treatment requires complete bypass of the duodenum 40, an obstruction (e.g., a total obstruction) of the pylorus 60 may be identified, and an anastomosis 15 may be formed between the stomach 20 and the jejunum 30; this anastomosis may be known as a gastrojejunostomy. 1 illustrates an exemplary bypass procedure in which a flow restricting device 50 is positioned within the pylorus 60, thereby restricting access (e.g., complete bypass) of food material from the stomach 20 to the duodenum 40. As shown in FIGS. 1 and 2, a lumen-apposing metal stent (LAMS), such as stent 10, may be placed between the stomach 20 and the jejunum 30, thereby forming an anastomosis 15, allowing food material (fluids, liquids, chyme, etc.) to pass from the stomach 20 into the jejunum 30 through the lumen 11 of the stent 10.

[0034] Stent 10 is held in place by flanges 12 located on both the proximal and distal ends of stent 10. Flanges 12 are located on either side of an intermediate region 13 having a smaller radial diameter than flanges 12. Flanges 12 and intermediate region 13 are configured to engage tissue surfaces 14 of both stomach 20 and jejunum 30 and exert both radial and compressive forces on tissue 14 to assist in retaining stent 10 at anastomosis 15.

[0035] While stent 10 is shown as being used in forming an anastomosis 15 between stomach 20 and jejunum 30, it is envisioned that stent 10 may also be used to drain a pancreatic collection, pancreatic duct, bile duct, or gallbladder into the stomach or duodenum, to treat a stricture in a blood vessel, to maintain a fluid opening or pathway in a blood vessel, urinary tract, bile duct, tracheobronchi, esophagus, or renal tract, or in some cases, to position a device such as a prosthetic valve or filter within a body lumen. Although illustrated as a stent, stent 10 may be any of a number of 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 collection, gallbladder, etc.

[0036] Once deployed, it is important that the lumen-apposing stent remain in place, holding the two lumens together and bridging the opening in their walls. If it migrates from its position, the contents of the lumen may leak into the peritoneal cavity. This poses a significant risk to the patient's health if partially digested food leaks from the stomach, digestive fluids leak from the bile or pancreatic duct, or infected necrosis leaks from a pancreatic fluid collection into the abdomen. The present disclosure provides methods, techniques, devices, and systems that enable physicians to prevent migration of lumen-apposing stents.

[0037] The present disclosure provides devices that prevent migration of a luminal apposing stent and / or anchor two tissue planes and / or stents together, preventing the distal tissue from migrating away from the proximal tissue during and / or after stent placement.

[0038] In some embodiments of the present disclosure, flanged retaining members are integrally disposed within stent 10 and biased to exert a compressive force against tissue 14 of anastomosis 15. As noted above, the stents described herein may be used during several procedures, for example, when creating an anastomosis for gallbladder drainage.

[0039] 3A and 3B show a stent 310 comprising flange retention members 316. The flange retention members 316 include retention member ends 318 configured to engage with the flanges 312 of the stent 310. In some embodiments, the retention member ends 318 may be hooks, arrows, or other features or shapes configured to engage with and / or mechanically couple with structure of the stent 310. As a particular example, the retention member ends 318 may be hook-shaped and may hook onto and / or mechanically couple to portions of the wire mesh on both the distal and proximal flanges 312 of the stent 310. Additionally, as shown, a pair of flange retention members 316 are provided, integrally formed to couple to each pair of distal and proximal flanges 312 and exert a compressive force against each pair of distal and proximal flanges 312.

[0040] The flange retaining member 316 may be made from nitinol and may include various shapes or designs (see, e.g., FIGS. 4 and 5). Generally, the flange retaining member 316 may be integrally packaged with the stent 310 and a delivery device. Various stent delivery devices are known in the art. For example, a typical stent delivery device holds the stent 310 in a compressed, stretched state within a delivery sheath 302. The delivery sheath 302 is configured to be delivered to the anastomosis site via an endoscope. During delivery, the stent 310 is held in a stretched, flat state by the sheath 302, as shown in FIG. 3A. However, once deployed, the flange retaining member 316 is biased to apply pressure in the direction of arrow 350, drawing the flange 312 into the tissue 14 of the anatomical structure (e.g., the stomach 20 and jejunum 30) where the anastomosis will be formed.

[0041] It is important to note that although only two flange retaining members 316 are shown herein, the stent 310 can include more than two flange retaining members 316, for example, three, four, five, six, etc.

[0042] FIG. 4 illustrates a flange retaining member 400, which in some embodiments may be implemented as flange retaining member 316. Flange retaining member 400 includes a distal retaining member end 462 and a proximal retaining member end 464, and a central biasing region 466. Central biasing region 466 may comprise pleats or tubes that are folded or stacked within one another and biased to return to a shortened length upon release from delivery device sheath 302. In other words, central biasing region 466 may be configured to be compressed to an extended state and biased to return to a shortened state. Thus, upon deployment, central biasing region 466 can return flange retaining member 400 to the shortened state, thereby exerting pressure in the direction of arrow 350 against flange 312.

[0043] 5 illustrates a flange retaining member 500 that may be implemented as flange retaining member 316 in some embodiments. Flange retaining member 500 includes a distal retaining member end 562 and a proximal retaining member end 564, as well as a central biasing region 566. Central biasing region 566 may comprise a spring. The spring may be configured to be stretched to an extended state and biased to return to a shortened state. Thus, upon deployment, central biasing region 566 can return flange retaining member 500 to the shortened state, thereby exerting pressure on flange 312 in the direction of arrow 350.

[0044] As mentioned above, stents are often used to drain adherent structures (e.g., pancreatic fluid collections, etc.). However, stents may also be used with non-adherent structures (e.g., the stomach, gallbladder, and jejunum). If the stent is dislodged or removed prematurely, there is a risk of leakage, which can be catastrophic for the patient and require surgical intervention.

[0045] The present disclosure provides stents with additional members configured to provide internal support for the stent. The additional members and internal support can reduce the likelihood of the stent collapsing or migrating.

[0046] 6 shows a stent delivery device 600 having a handle 603 and a tip 601. The tip 601 may be configured to form an anastomosis 15, and the handle 603 may be configured to deploy a stent 610 within 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 proximally to the anastomosis 15. As described above, the delivery device includes a sheath within which the stent is held in a compressed, extended position. The delivery device 600 includes a sheath 602 from which the stent 610 can be deployed. Additionally, delivery device 600 includes a plastic pigtail stent 670 mounted on or distal to sheath 602, and a pigtail stent pusher 604 configured to deploy the pigtail stent within the lumen of stent 610 once stent 610 is deployed (see FIG. 7). Pigtail stent pusher 670 may be used to push pigtail stent 670 out of the sheath so that pigtail stent 670 is deployed and the ends are straight both proximal and distal to stent 610.

[0047] Pigtail stent 670 is located within the lumen of stent 610, with the two curled ends of the stent providing a secondary means of holding the two lumens together. The pigtail stent may be hollow, allowing for fluid flow and drainage and providing a backup if primary lumen apposition stent 610 becomes clogged. In some embodiments, delivery device 600 may be packaged to include both stent 610 and pigtail stent 670.

[0048] 7 shows an example of a deployed stent 610 and a pigtail stent 670. The outer diameter of the pigtail stent 670 may be small compared to 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 may be similar, so that they can both exert pressure on the lumen wall. It should be understood that the device shown in this figure is not to scale, and furthermore, the size of the pigtail stent 670 relative to the stent 610 may vary.

[0049] 8A and 8B show a stent 810 and a delivery system 800 including a sheath 802 within which the stent 810 is held in a compressed, extended position from which the stent 810 can be deployed. The delivery system 800 includes a distal end 801 for forming an anastomosis as described above. The stent 810 further includes a flange 812 and a flange support structure 880. The auxiliary support structure 880 may be a formed metal wire, a spring, or other structure; when the stent 810 is deployed and the flange 812 opens to its expanded state, the auxiliary support structure 880 also opens and provides support to the flange 812. In some embodiments, one of the flanges may include the flange support structure 880. In other embodiments, both flanges 812 may include the flange support structure. In some embodiments, the auxiliary support structure 880 may be provided in the intermediate region 813 in addition to or as an alternative to the flange 812. Providing support to the flanges helps prevent migration of the stent from the anastomosis.

[0050] In some embodiments, auxiliary support structure 880 may be provided on either or both of the distal and proximal flanges 812, thereby allowing the flanges 812 to be more rigid while the intermediate (or central saddle) region 813 remains flexible. Thus, the radial and axial stiffness profiles of the flanges 812 can be decoupled from the intermediate region 813.

[0051] 9A and 9B show alternatives for providing support to the flange. Figures 9A and 9B show alternative designs for stents 910 and 910', respectively, in an expanded state. As can be seen, flange 912 and secondary support structure 980 are expanded, with secondary support structure 980 providing radial and axial support to the expanded flange 912.

[0052] As mentioned above, stents are often placed between two non-adherent structures (e.g., gastrojejunostomy, hepatogastrostomy, gallbladder drainage to either the stomach or duodenum, etc.). Once the anastomosis is achieved, it is important to ensure that the stent remains in place. For example, a migrated stent may lead to leakage of infectious materials into the peritoneal cavity, resulting in infection or other complications, and may require surgical intervention to correct. The present disclosure provides auxiliary compression and / or expansion support for a stent. In particular, the auxiliary compression support structure may carry some of the tension between the two non-adherent structures, thereby relieving some of the tension carried by the stent flanges.

[0053] FIG. 10 shows an auxiliary compression support structure 1000 that may be provided and deployed within a stent. The auxiliary compression support structure 1000 includes proximal and distal flange retention ends 1002 and a spring structure 1004 disposed between the retention ends 1002. The auxiliary compression support structure 1000 may be formed from a metal or a shape-memory alloy (e.g., Nitinol) and biased to return to its formed shape. Thus, the auxiliary compression support structure 1000 may be flattened into a delivery device (e.g., a catheter delivery tube, etc.) and delivered within the stent. The retention ends 1002 may be configured (or shaped) to mechanically couple to the outer wall of the flange 12 of the stent 10. Thus, the spring 1004 relieves some tension from the flange itself, increasing the force on the stent 10.

[0054] 11A, 11B, and 11C show images illustrating how the auxiliary compression support structure 1000 of FIG. 10 may be deployed within a deployed stent (e.g., as shown in FIG. 2). Referring first to FIG. 11A, once the stent 10 is deployed, the distal flange retention end 1002 of the auxiliary compression support structure 1000 may be deployed (e.g., using a catheter and deployment handle, etc.) onto the distal flange 12 of the stent 10.

[0055] 11B , the proximal flange retaining end 1002 of the auxiliary compression support structure 1000 may be deployed (e.g., using the same catheter and deployment handle) onto the proximal flange 12 of the stent 10. It should be appreciated that when both the distal and proximal flange retaining ends 1002 of the auxiliary compression support structure 1000 are deployed onto their respective distal and proximal flanges 12, tension is released from the flange 12 of the stent 10, and further, the stent 10 is more compressed than it would be without the assistance of the auxiliary compression support structure 1000. Thus, the diameter of the flange 12 increases. That is, the longitudinal length of the stent 10 is reduced by the compressive support of the auxiliary compression support structure 1000, further resulting in an increase in the diameter of the flange 12.

[0056] 11C shows an axial view of the stent 10 with an auxiliary compression support structure 1000 disposed therein. FIG. 11C shows a retention end 1002 coupled to the flange 12 and a spring 1004 disposed within the lumen of the stent 10. In some embodiments, the size and shape of the retention end may be tailored to a particular flange diameter. Additionally, the spring 1004 may be tailored to have a particular spring constant and unbiased length for various lengths of stents or procedures.

[0057] In another embodiment, the auxiliary compression support structure 1000 may be coupled directly to the flanges of the stent 10 during manufacture. Similar to the concept shown in Figure 3, the stent 10 can assume an elongated position when compressed within a delivery catheter and the shape shown in Figure 1 IB when the stent 10 is deployed.

[0058] In some embodiments, the auxiliary compression support structure 1000 may be provided by another stent. For example, FIG. 12 shows an inner stent 10a positioned in an anastomosis with an outer stent 10b deployed around the inner stent 10a. In some embodiments, the inner stent 10a may have a flange with a larger diameter than the outer stent 10b, which may have a higher compression force. In this manner, the flange diameter of the inner stent 10a may be increased as described above.

[0059] Generally, the stents described herein may have an expanded outer diameter in the range of 6 to 70 millimeters (mm), a shortened length (e.g., uncompressed length) in the range of 8 to 120 mm, and a midsection diameter in the range of 5 to 30 mm. Additionally, the support structures described herein may have dimensions sized to mechanically couple to the deployed stent and provide auxiliary support as detailed herein.

[0060] In some embodiments, the devices disclosed herein may be made from metals, metal alloys, polymers (some examples of which are disclosed below), metal-polymer composites, ceramics, combinations thereof, or other suitable materials. Some examples of suitable polymers include polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), polyoxymethylene (POM, e.g., DELRIN® available from DuPont), polyether block esters, polyurethanes (e.g., Polyurethane 85A), polypropylene (PP), polyvinyl chloride (PVC), polyetheresters (e.g., ARNITEL® available from DSM Engineering Plastics), ether- or ester-based copolymers (e.g., butylene / poly(alkylene ether) phthalates and / or other polyester elastomers such as HYTREL® available from DuPont), polyamides (e.g., DURETHAN® or Elf® available from Bayer), and the like. CRISTAMID™ available from Atochem), elastomeric polyamides, block polyamide / ethers, polyether block amides (PEBA, e.g., available under the trade name PEBAX®), ethylene vinyl acetate copolymer (EVA), silicone, polyethylene (PE), MARLEX® high density polyethylene, MARLEX® low density polyethylene, linear low density polyethylene (e.g., REXELL®), polyester, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polytrimethylene terephthalate, polyethylene naphthalate (PEN), polyether ether ketone (PEEK), polyimide (PI), polyetherimide (PEI), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), polyparaphenylene terephthalamide (e.g., KEVLAR®), polysulfone, nylon, nylon 12 (EMS AmericanExamples of suitable materials include PEGs (e.g., GRILAMID® available from Grillon), perfluoro(propyl vinyl ether) (PFA), ethyl vinyl alcohol, polyolefins, polystyrene, epoxies, 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, and the like. In some embodiments, the sheath may be blended with a liquid crystal polymer (LCP). For example, the blend may contain up to about 6% LCP.

[0061] In at least some embodiments, some or all of the devices disclosed herein may be doped with, made from, or otherwise include a radiopaque material. A radiopaque material is understood to be a material capable of producing a relatively bright image on a fluoroscopy screen or another imaging technique during a medical procedure. This relatively bright image aids the user in determining the device's location during the procedure. Some examples of radiopaque materials include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloys, polymeric materials loaded with radiopaque fillers, and the like. Additionally, other radiopaque marker bands and / or coils may also be incorporated into the device design.

[0062] In some embodiments, the material 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 ELGILOY®, PHYNOX®), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS:R30035, such as MP35-N™), nitinol, platinol, and the like, and others.

[0063] It will be understood that this disclosure is, in many respects, merely illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of steps, without exceeding the scope of the disclosure. This may include, to the extent appropriate, the use of any of the features of one illustrative embodiment used in other embodiments. The scope of the invention will, of course, be defined in the language in which the appended claims are expressed.

Claims

1. a radially expanding tubular framework having a first end region, a second end region, an intermediate region positioned 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 comprises a first flange and the second end region comprises a second flange; a secondary support structure configured to provide support to the first flange and the second flange when the stent is in an expanded state; A system comprising:

2. The system of claim 1 , wherein the first flange and the second flange are configured to atraumatically engage body tissue.

3. the secondary support structure comprises a second radially expanding tubular framework having a first end region, a second end region, an intermediate region positioned between the first end region and the second end region, and a lumen extending from the first end region to the second end region; 3. The system of claim 1 or 2, wherein the first end region of the second radially expanding tubular framework comprises a first flange and the second end region of the second radially expanding tubular framework comprises a second flange.

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

5. 5. The system of claim 4, wherein the first radially expanding tubular framework has a first longitudinal compressive force and the second radially expanding tubular framework has a second longitudinal compressive force greater than the first longitudinal compressive force.

6. The system of claim 1 or 2, wherein the auxiliary support structure comprises a proximal flange retaining member, a distal flange retaining member, and a spring coupled between the proximal flange retaining member and the distal flange retaining member.

7. 7. The system of claim 6, wherein the first and second flanges of the radially expanding tubular framework have a first diameter, and the proximal and distal flange retaining members have a second diameter, the second diameter being equal to or greater than the first diameter minus 5 millimeters (mm) and equal to or less than the first diameter plus 5 mm.

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

9. 3. The system of claim 1, wherein the auxiliary support structure comprises at least one spring integrally coupled 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. 10. The system of claim 9, wherein the spring comprises pleats or folds biased to apply a compressive force to the first flange and the second flange.

11. The system of claim 9 , wherein the spring comprises a coil.

12. The system of any one of claims 1 to 11, 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 flange and the second flange.

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

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

15. The stent of any one of claims 1 to 14, wherein the radially expanding tubular framework comprises a coating disposed on the radially expanding tubular framework.

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