Self-expanding tissue luminal stent with enhanced drainage function

Abstract

The present disclosure provides a tissue lumen stent having an elongated tubular configuration and a shortened configuration. In the shortened configuration, the upstream end, the downstream end, or both the upstream and downstream ends are radially expanded flange and / or flared structures, while the region therebetween is generally cylindrical. The upstream flange structure has a greater maximum transverse dimension, axial width, and / or axial radius than the downstream flange structure, and may include a tapered portion having an axial length at least as long as the maximum diameter of the saddle region when the body is in the shortened configuration.

Description

[Technical Field]

[0001] FIELD OF THE INVENTION This application relates generally to medical methods and devices. More particularly, the present disclosure relates to luminal stents and methods of use for maintaining luminal patency in medical procedures. [Background technology]

[0002] Tissue luminal stents are often used in medical procedures to maintain luminal patency. Typically, a tissue luminal stent has a body with upstream and downstream ends and a central region between the upstream and downstream ends. A medical procedure can be provided that includes (a) accessing a patient's biliary system with an endoscope, and (b) deploying the tissue luminal stent within the patient's biliary system such that the tissue luminal stent contacts a lumen within the patient's biliary system, such as the common bile duct, pancreatic duct, or hepatic duct. Summary of the Invention

[0003] The embodiments described herein provide tissue lumen stents with features for improving, enhancing, or promoting drainage. Generally, tissue lumen stents have an elongated tubular configuration and a shortened configuration. In the shortened configuration, the upstream end, the downstream end, or both the upstream and downstream ends are radially expanded flange and / or flared structures, while the region therebetween is generally cylindrical.

[0004] In some cases, when the stent is in the shortened configuration, the upstream flange structure may have a larger maximum transverse dimension, axial width, and / or axial radius than the downstream flange structure and may include a tapered portion having an axial length at least as long as the largest diameter of the saddle region of the body in the shortened configuration. On the other hand, some embodiments are characterized in that the downstream flange structure has a larger maximum transverse dimension, axial width, and / or axial radius than the upstream flange structure. Alternatively or additionally, the upstream flange structure may include a distal-most opening having a diameter larger than the largest inner diameter of the saddle region when the body is in the shortened configuration. In certain embodiments, the body includes a coated mesh, and in some cases, may include both coated and uncoated meshes. Also, some embodiments include a coating or membrane that covers at least the cylindrical saddle region of the stent and, optionally, may cover either or both the upstream flange structure and / or the downstream flange structure.

[0005] In some embodiments, the present disclosure may be embodied as a stent. For example, the stent may include a body having an elongated tubular configuration and a shortened configuration, wherein an upstream end of the body expands into an upstream configuration and a downstream end of the body expands into a flange configuration in the elongated tubular configuration. The body may include a cylindrical saddle region disposed between the upstream configuration and the flange configuration, and a channel extending helically around the periphery of the body, the channel being formed on the exterior of the body and mirrored on the interior of the body.

[0006] Alternatively or additionally, in any of the stent embodiments described above, the channels have a constant pitch along the length of the body. Alternatively or additionally, in any of the stent embodiments described above, the pitch of the channels increases along the length of the body.

[0007] Alternatively or additionally, in any of the stent embodiments described above, the pitch increases along the length of the body from the upstream end to the downstream end. Alternatively or additionally, in any of the stent embodiments described above, the width of the channel can be wider at the upstream end of the body than at the downstream end of the body.

[0008] Alternatively or additionally, in any of the stent embodiments described above, the width of the channel can be wider at the downstream end of the body than at the upstream end of the body. Alternatively or additionally, in any of the stent embodiments described above, the upstream structure includes a flange or a flare.

[0009] In some embodiments, the present disclosure may be embodied as a stent. For example, the stent may include a body having an elongated tubular configuration and a shortened configuration, wherein an upstream end of the body expands into an upstream structure and a downstream end of the body expands into a flange structure in the elongated tubular configuration. The body includes a cylindrical saddle region disposed between the upstream structure and the flange structure, and a covering covering the downstream end of the body and the cylindrical saddle region. The upstream structure also includes a plurality of anti-migration fins disposed on an outer surface thereof.

[0010] Alternatively or additionally, in any of the stent embodiments described above, the plurality of anti-migration fins comprise wire fins arranged to flare outward from the upstream structure.

[0011] Alternatively or additionally, in any of the stent embodiments described above, the plurality of anti-migration fins include tips that face toward the downstream end of the body. Alternatively or additionally, in any of the stent embodiments described above, at least one of the anti-migration fins may have a tip that faces toward the downstream end of the body, and at least another of the anti-migration fins may have a tip that faces toward the upstream end of the body.

[0012] Alternatively or additionally, in any of the stent embodiments described above, the upstream structure may comprise a flare. In some embodiments, the present disclosure may be embodied as a stent. For example, the stent may include a body having an elongated tubular configuration and a shortened configuration, wherein an upstream end of the body expands to an upstream flange structure and a downstream end of the body expands to a downstream flange structure in the elongated tubular configuration. The body may include a cylindrical saddle region disposed between the upstream and downstream flange structures, the cylindrical saddle region having a curve along a longitudinal axis of the body.

[0013] Alternatively or additionally, in any of the stent embodiments described above, the cylindrical saddle region may comprise another curve along the axial direction of the body. Alternatively or additionally, in any of the stent embodiments described above, the curve is closer to the upstream flange structure than to the downstream flange structure, or closer to the downstream flange structure than to the upstream flange structure.

[0014] In some embodiments, the present disclosure may be embodied as a method. For example, a method of treating a patient may include accessing the patient's biliary system with an endoscope and deploying a stent within the patient's biliary system. The stent may include a body having an elongated tubular configuration and a shortened configuration, wherein an upstream end of the body expands into an upstream structure and a downstream end of the body expands into a flange structure. The body may include a cylindrical saddle region disposed between the upstream structure and the flange structure, and a channel extending helically around the body, the channel being formed on an outer surface of the body and mirrored on an inner surface.

[0015] Alternatively or additionally, in any of the method embodiments described above, the channels may have a constant pitch along the length of the body. Alternatively or additionally, in any of the method embodiments described above, the pitch of the channels increases along the length of the body.

[0016] Alternatively or additionally, in any of the method embodiments described above, the pitch increases along the length of the body from the upstream end to the downstream end. Alternatively or additionally, in any of the method embodiments described above, the width of the channel is wider at the downstream end of the body than at the upstream end of the body.

[0017] To facilitate easy identification of any element or description of an operation, the most significant digit(s) of a reference number refers to the number of the figure in which that element first appears. [Brief explanation of the drawings]

[0018] [Figure 1A] Diagram showing the biliary system. [Figure 1B] 1B shows the biliary tree of FIG. 1A with a stent 120 placed therein. [Figure 2A] 1 illustrates a stent 200 in accordance with at least one embodiment of the present disclosure. [Figure 2B] 2 shows further details of stent 200. FIG. [Figure 3] 1 illustrates a stent 300 in accordance with at least one embodiment of the present disclosure. [Figure 4A] FIG. 4 illustrates a stent 400a in accordance with at least one embodiment of the present disclosure. [Figure 4B] FIG. 4 illustrates a stent 400b in accordance with at least one embodiment of the present disclosure. [Figure 5A] FIG. 5 illustrates a stent 500a in accordance with at least one embodiment of the present disclosure. [Figure 5B] FIG. 5 illustrates a stent 500b in accordance with at least one embodiment of the present disclosure. [Figure 6A] FIG. 6 illustrates a stent 600a in accordance with at least one embodiment of the present disclosure. [Figure 6B] FIG. 6 illustrates a stent 600b in accordance with at least one embodiment of the present disclosure. [Figure 7] Diagram showing the biliary system of a patient with a stent in place. [Figure 8A] FIG. 8 illustrates a stent 800a in accordance with at least one embodiment of the present disclosure. [Figure 8B] FIG. 8 illustrates a stent 800b in accordance with at least one embodiment of the present disclosure. [Figure 8C] FIG. 8 illustrates a stent 800c in accordance with at least one embodiment of the present disclosure. [Figure 8D] FIG. 8 illustrates a stent 800d in accordance with at least one embodiment of the present disclosure. [Figure 9A] Diagram showing the patient's biliary system. [Figure 9B] 9B shows the biliary tree of FIG. 9A in further detail. DETAILED DESCRIPTION OF THE INVENTION

[0019] In this disclosure, the terms antegrade, retrograde, downstream, upstream, proximal, distal, inferior, superior, downside, and superior are used to refer to various directions. Unless the context clearly indicates otherwise, the terms antegrade, downstream, proximal, inferior, and inferior are used interchangeably to generally refer to a direction along fluid flow and toward the surgeon along devices and instruments. Conversely, the terms retrograde, upstream, distal, superior, and superior are generally used interchangeably to refer to a direction against fluid flow and away from the surgeon along devices and instruments. However, it should be noted that this nomenclature is defined for clarity of the following description, not to limit the scope of the invention. While the exemplary embodiments disclosed herein focus on insertion and placement in a retrograde direction, the disclosed methods, systems, and devices may be placed in an antegrade direction under some circumstances. In such circumstances, "upstream" and "downstream" may refer to opposite meanings.

[0020] As mentioned above, this disclosure describes an expandable stent for use in a patient's biliary system. Accordingly, a description of the biliary system is provided herein. Bile, necessary for the digestion of food, is secreted by the liver and passes through bile-carrying channels into the left hepatic duct 102 and the right hepatic duct 104. These two hepatic ducts join to form the common hepatic duct 106. After leaving the liver, the common hepatic duct 106 joins with the cystic duct 108, which extends from the gallbladder 110, which stores bile, to form the common bile duct 112. The common bile duct 112 further joins with the pancreatic duct 114, which extends from the pancreas, and delivers bile, pancreatic juices, and insulin to the descending portion of the duodenum 116 via the papilla of Vater 118. A sphincter known as the sphincter of Oddi is located where the papilla of Vater 118 opens into the duodenum 116 and prevents material in the duodenum 116 from flowing back into the common bile duct 112.

[0021] Tumor growth, hyperplasia, pancreatitis, or other strictures in or around the biliary system can obstruct or block the flow of fluid from the liver, gallbladder, and / or pancreas to the duodenum. To alleviate the effects of the stricture, it may be necessary to place a stent in a portion of the biliary system. Stents can be placed endoscopically. One procedure for placing a stent is endoscopic retrograde cholangiopancreatography (ERCP). ERCP is a technique that combines endoscopy and fluoroscopy to diagnose and treat specific problems in the biliary or pancreatic systems. This procedure involves inserting an endoscope down the esophagus, through the stomach, and into the duodenum, then inserting various accessories through the endoscope's instrument channels and into the biliary or pancreatic system via the papilla of Vater. Alternatively, a specialized, thin-bore endoscope, sometimes called a peroral cholangioscope, can be inserted directly into the biliary or pancreatic duct.

[0022] Thus, stents currently placed by ERCP are used to facilitate drainage of bile through the biliary system. Drainage is a common desire for self-expanding stents, allowing residual drainage from secondary sources. This disclosure describes and illustrates several self-expanding stents with improved drainage features or characteristics.

[0023] 1B shows an exemplary biliary stent 120 placed at the lower end of the common bile duct 112. In this configuration, the stent 120 may be used to treat papillary strictures. In other embodiments, the stent 120 may be designed to be longer to span a biliary stricture further upstream. The stent 120 has a downstream end 122 that protrudes into the duodenum 116 and an upstream end 124 that extends into the common bile duct 112. The stent 120 is shown in a generally radially expanded and axially shortened state so as to continuously contact the wall of the common bile duct 112 along its entire length, or at least in some locations.

[0024] FIG. 2A illustrates a stent 200 in accordance with at least one embodiment of the present disclosure. The stent 200 includes a body 202 having a generally tubular structure. The body 202 may be formed from a woven filament braid. The filaments are typically metal wires, more typically nickel-titanium or other metal wires with superelastic or shape-memory properties. Alternatively, when elasticity is less important, the filaments may be formed from a polymeric material such as polypropylene, polyethylene, polyester, nylon, PTFE, or the like. In some cases, bioabsorbable or biodegradable materials may be used, typically biodegradable polymers such as poly-L-lactic acid (PLLA).

[0025] The body 202 has both an elongated tubular configuration (during stent delivery) and a shortened configuration (during deployment), in which the downstream and upstream ends of the body radially expand (as the body shortens). One or both ends of the body 202 may expand into a flange 204 (e.g., a double-walled flange structure). Such a "double-walled flange structure" may be formed when a portion of the body moves inward (toward the center), typically at the extreme end but optionally at a portion further inward from the end. The portion of the body moves such that a pair of adjacent body segments of the portion are drawn toward their bases to expand radially into a pair of adjacent annular rings defining the flange 204 with a curved centerline or crest. After shortening and deployment of such a double-walled flange structure, the body 202 may further have a cylindrical saddle region 206 formed between the flanges 204.

[0026] Additionally, the body 202 may have a channel 208 that spirals around the body 202 and the cylindrical saddle region 206. The channel 208 may run the entire length of the stent 200. Note that FIG. 2A shows an external view of the stent 200, while FIG. 2B shows two longitudinal cross-sections of the stent 200, illustrating the inner lumen 210 of the stent 200. As can be seen from these figures, the channel 208 depicted on the outer surface of the stent 200 is also transferred to the inner lumen 210. As described herein, the stent 200 may be formed as a single-walled braided device. In this manner, the channel 208 extending the entire length of the stent 200 will be depicted on both the outer and inner surfaces of the body 202, thereby facilitating the flow of bile (or other substances) through the stent 200. As shown, the channel 208 can be defined from the distal end of the stent 200 to the proximal end of the stent 200 .

[0027] When the stent 200 is formed from shape memory alloy wires such as Nitinol or Elgilloy, the wires can have a relatively small diameter. The diameter typically ranges from 0.001 inch (approximately 0.0254 mm) to 0.02 inch (approximately 0.508 mm), and typically ranges from 0.002 inch (approximately 0.0508 mm) to 0.01 inch (approximately 0.254 mm). The braid can include as few as 10 metal wires and as many as 200 metal wires, more typically 20 to 200 metal wires. In exemplary cases, the wires are round, have diameters ranging from 0.003 inch (approximately 0.0762 mm) to 0.007 inch (approximately 0.1778 mm), and have a total number of wires ranging from 24 to 60. The wires can be braided into a tubular shape by conventional techniques, and the tubular shape can be heat treated to impart the desired shape memory properties. Typically, the braided tube is formed into a desired final (e.g., deployed) configuration with a flange at each end. Such a flanged configuration can then be heat set or formed into the braid so that, in the absence of a radial restraining force or an axial elongation force, the stent will assume a shortened configuration with a flange at each end. Such a shortened memory configuration allows the stent to be delivered in a constrained configuration (e.g., a radially or axially elongated configuration) and then released from the restraint so that the body 202 will assume the desired flanged configuration (e.g., flanges 204) at the target site.

[0028] However, in alternative embodiments, the woven filament braid can be heat-set into an elongated tubular configuration and transitioned to a shortened, flanged configuration by application of an axial compression force. Such axial compression compresses the flanges and radially expands them, allowing for controllable, adjustable shortening, allowing the stent to be adjusted to a desired length. According to this embodiment, the woven filament braid can be heat-set into an expanded configuration and includes a mechanism for mechanically shortening the stent beyond its normal, fully expanded configuration, allowing the stent to be automatically or manually adjusted to the length of the stenosis. The shortened structure and flanges can be formed by providing sleeves, tubes, rods, filaments, tethers, springs, elastic members, etc., which cause the shortened structure and flanges to form upon application of a spontaneous or applied force to the tube. Optionally or additionally, the body 202 can have weakened or reinforced regions or be otherwise modified to form the desired flange shape upon application of an axial shortening force.

[0029] The stents described herein (e.g., stent 200) can be adapted to be delivered by a delivery device, typically an endoscopic delivery catheter. The catheter typically has a small diameter ranging from 1 mm to 8 mm, typically ranging from 2 mm to 5 mm. Thus, the elongated tubular configuration of body 202 typically has a diameter smaller than the diameter of the catheter, typically ranging from 0.8 mm to 7.5 mm, more typically ranging from 0.8 mm to 4.5 mm. The flange structure in such a configuration is highly expandable, typically ranging from 3 mm to 70 mm, more typically ranging from 5 mm to 40 mm. Various stents having different lengths for use in strictures at different sites can be provided, for example, in kit form. In some embodiments, the overall length of the stent in its fully expanded / deployed state is 7 cm, 9 cm, and 11 cm. In other embodiments, the overall length is 6 cm, 8 cm, and 10 cm. In yet another embodiment, the stent is between 1 cm and 6 cm. The cylindrical saddle region 206 of the stent 200 often does not increase in diameter during deployment, but may optionally increase in diameter from 2 mm to 50 mm, more typically from 5 mm to 12 mm. Lumens or passageways through the deployed stent 200, if present, typically vary in diameter from as little as 0.2 mm to as much as 40 mm, more typically from 1 mm to 20 mm, and even more typically slightly smaller than the expanded outer diameter of the cylindrical saddle region 206. The length of the body can vary considerably. Typically, when in the elongated tubular configuration, the body length ranges from 7 mm to 200 mm, usually from 12 mm to 70 mm. When deployed, the body 202 can be shortened, typically by at least 20%, more typically by at least 40%, and often by 70% or more. Thus, the shortened length typically ranges from 2 mm to 80 mm, usually from 30 mm to 60 mm.

[0030] The body 202 of the stent 200 may be comprised solely of a woven filament braid, with no other coatings or layers. However, in other cases, the stent 200 may further include a membrane or other coating formed over at least a portion of the body 202. Often, the membrane is intended to prevent or inhibit tissue ingrowth so that the device can be removed after being in place for weeks, months, or longer. Suitable membrane materials include polytetrafluoroethylene (PTFE), porous PTFE (EPTFE), silicone, polypropylene, urethane polyether block amide (PEBA), polyethylene terephthalate (PET), polyethylene, C-Flex® thermoplastic elastomer, Krator® SEBS and SBS polymers, and the like.

[0031] Such a membrane may be formed over the entire or only a portion of the body 202 of the stent 200, over the entire exterior or interior of the body 202. The membrane is typically elastomeric so as to conform to the body 202 in both the elongated tubular configuration and the shortened configuration. Optionally, the membrane may be formed over only the central portion of the cylindrical saddle region 206, in which case the membrane need not be flexible when the central portion of the cylindrical saddle region 206 is not radially expanded.

[0032] The coating or membrane inhibits tissue ingrowth into the interstices of the wire mesh, minimizing fluid leakage when the stent is deployed. Reducing tissue ingrowth improves the removability of the stent. In contrast to vascular stents, which are typically not designed for migration or retrieval, the stents described herein are collapsible and designed to be removable and retrievable. Additionally, the stents typically do not include barbs or other sharp projections that are used on other types of stents to permanently anchor them to surrounding tissue.

[0033] Different portions of a stent may or may not be coated depending on the particular application. In some embodiments, one end of a stent may be uncoated. In some embodiments, any stent disclosed herein may include a coating on one end of the stent. The coating may be provided on the flanged or non-flanged end of the stent. For example, if one end of a stent is deployed in the liver and the other end in the stomach, the end of the stent located in the liver may have a cylindrical saddle region 206 and be uncoated, while the end that contacts the stomach may be covered. If one end of a stent is deployed near the papilla of Vater and the duodenum and the other end is deployed in the bile duct, the end adjacent to the bile duct may be covered. In some embodiments, any stent disclosed herein may include a coating on both ends of the stent. In some embodiments, the central portion or the portion between the upstream and downstream flanges may be uncoated. The uncoated central portion may be used for drainage of fluid from the pancreatic duct when both ends of the stent are placed in the duodenum and bile duct.

[0034] In some embodiments, the cylindrical saddle region 206 is coated to prevent fluid leakage outside the cylindrical saddle region 206 of the stent 200. The stents disclosed herein can be deployed within the body, as described herein, such that the cylindrical saddle region 206 forms a fluid conduit between body lumens within the peritoneum. The coated cylindrical saddle region 206 can prevent leakage into the peritoneum. Leakage of biological materials into the peritoneum can cause serious complications. As a result, stents can have a coating to prevent fluid or materials from leaking outside the cylindrical saddle region 206 of the stent 200. Coatings can also be used on the ends of the stent that are configured to connect to the stomach or duodenum.

[0035] Examples of manufacturing techniques that can be used to produce the stents disclosed herein include the use of laser cutting, braiding, welding, etching, and wire forming. A membrane material, such as silicone, can be applied to the wire stent frame to prevent the passage of fluids through the stent wall. The membrane or coating material can be applied by painting, brushing, spraying, dipping, or molding.

[0036] Additionally, in some embodiments, stent 200 can be formed by braiding a wire (or multiple wires) on a mandrel and then crimping a sleeve over the mandrel to form stent 200. In particular, the mandrel can have an inverse shape of the channels 208 cut into the mandrel, and a matching sleeve with protruding channel 208 structures can fit over the mandrel to form the channels 208 in the body 202 of stent 200. Additionally, the formed stent can be annealed using an annealing process.

[0037] 3 illustrates a stent 300 according to some embodiments of the present disclosure. Similar to stent 200 of FIGS. 2A and 2B, stent 300 may have a body 302, a flange 304, a cylindrical saddle region 306, and a channel 308. However, stent 300 may have flange 304 at one end and a flare 310 at the opposite end. Generally, flare 310 is configured to prevent or inhibit downstream migration of stent 300.

[0038] 4A and 4B show stents 400a and 400b, respectively, according to some embodiments of the present disclosure. The stents 400a and 400b shown in these figures have a body 402, a flange 404, a cylindrical saddle region 406, and channels 408a and 408b. However, the helical channels 408a and 408b are not symmetrical. For example, FIG. 4A shows stent 400a having channel 408a, which is wider at the upstream end of stent 400a and narrows as channel 408a extends (or helically wraps) along the length of stent 400a.

[0039] Similarly, FIG. 4B shows a stent 400b having a channel 408b. The channel 408b is narrower at the upstream end of the stent 400b. The channel 408b widens as it extends (or spirals) along the length of the stent 400b. In some applications, repeated inflows into the spiral channel can create a path for fluid to flow along the length of the stent such that the total volume of fluid exceeds the channel's capacity, potentially causing backflow or channel blockage. However, the asymmetric channels shown in these figures can overcome this limitation. Similarly, a wider inlet channel (e.g., channel 408a) can provide more opportunities for alignment with side branches and act as a funnel to direct fluid into the spiral channel. The wider inlet can also act as a reservoir, exerting a downstream force on the fluid volume and promoting continued flow through the channel.

[0040] 5A and 5B illustrate stents 500a and 500b, respectively, according to some embodiments of the present disclosure. The stents 500a and 500b shown in these figures include a body 502, a flange 504, a cylindrical saddle region 506, and channels 508 with different pitches 510a and 510b. More specifically, the helical channels 508 vary in spacing or distance between successive channels 508. For example, FIG. 5A illustrates stent 500a with channels 508 having a pitch 510a, which is wider than the pitch 510b of the channels 508 of stent 500b shown in FIG. 5B. In some instances, stents 500a and 500b can be intended for deployment at different sites based on the density (or pitch) of the channels 508.

[0041] 6A and 6B illustrate stents 600a and 600b, respectively, according to some embodiments of the present disclosure. Generally, stents 600a and 600b may be similar to Axios® stents available from Boston Scientific® and configured for delivery via a Hot Axios® device. For example, stents 600a and 600b may include a body 602, a flange 604, and a cylindrical saddle region 606. Notably, however, stents 600a and 600b include a curved region 608 within cylindrical saddle region 606. Curved region 608 allows for bending along the length of the stent.

[0042] In some embodiments, stents 600a and 600b can be used to manage symptomatic cholecystitis in patients who are high risk for surgery or who are not candidates for surgery. It should be noted that early laparoscopic cholecystectomy is considered the treatment of choice for acute cholecystitis in most cases. However, in elderly, critically ill, and patients with significant comorbidities, cholecystectomy is considered a high-risk procedure, and gallbladder drainage (GBD) is recommended as an alternative treatment.

[0043] To date, percutaneous transhepatic gallbladder drainage (PTGBD) is the most commonly used gallbladder drainage (GBD) technique in clinical practice. Although the technical success rate of PTGBD is high (98.9%), the clinical success rate is low (86.0%), and adverse events such as intrahepatic hemorrhage, pneumothorax, bile peritonitis, and pneumonia contribute to the procedure-related mortality rate of 4.0%. Because readmission rates are up to 42% and recurrence rates range from 4.1% to 22%, additional treatment options are needed to complement existing management strategies.

[0044] When deployed via a system such as the Hot Axios® system, the present stents 600a and 600b may be an option for high-risk or non-surgical patients. Published literature demonstrates clinical and technical success in treating symptomatic cholecystitis in high-risk or non-surgical patients by creating a new provisional opening between the gallbladder and the digestive tract (e.g., duodenum). EUS-GBD using Hot Axios® is an option for high-risk patients with acute cholecystitis when performed by an experienced endoscopist.

[0045] However, there is a potential risk that food impaction from the duodenal side could impede drainage and cause infection due to trapped contents in an already diseased gallbladder. The curved region 608 can be positioned to take advantage of natural anatomical pressure-driven and gravity-based drainage to allow drainage from the gallbladder while providing a more resistant pathway to reflux drainage and impaction from the duodenal region. This is more clearly shown in FIG. 7. For example, extending the bridge distance (i.e., the length of the cylindrical saddle region 606) can achieve a similar placement, resulting in even greater resistance to reflux drainage.

[0046] In some embodiments, stents 600a and / or 600b may include multiple curved regions 608, for example, to further increase resistance to reflux into the gallbladder. Additionally, in some embodiments, curved regions 608 may be formed across multiple planes on the device, which may provide better placement options, potential repositioning of the vessel (thereby reducing tension on the device and reducing the likelihood of migration), and / or may reduce reflux pressure.

[0047] In some examples, stents 600a and / or 600b may have a tapered body combined with curved region 608 to provide a wide inlet side for drainage and a narrow outlet side to prevent backflow pressure.

[0048] In some embodiments, stents 600a and 600b may be manufactured using a curved mandrel and a clamping sleeve. In some embodiments, stents such as the Axios® stent can be used in EUS-guided hepato-gastrostomy (HGS) procedures. Figures 8A, 8B, 8C, and 8D show stents 800a, 800b, 800c, and 800d, respectively. Stents 800a-800d have a body 802, a distal flange 804, and a straight or tapered proximal end 808a with a cylindrical saddle region 806 between the flange 804 and the proximal end 808a. The distal end with the flange 804 can be positioned for insertion downstream, i.e., toward the patient's stomach, while the proximal end 808a can be positioned upstream, i.e., toward the patient's liver. The proximal end 808a can have a looped end to aid in retrieval. Additionally, in some embodiments, stents 800a-800d can be bare (e.g., uncoated) or partially coated as shown with coating 810. In some embodiments, coating 810 enables stents 800a-800d to be used to bridge the gastro-hepatic drainage space, preventing leakage into the abdominal space while allowing tissue penetration for drainage and prevention of migration with the uncoated end positioned in the hepatic space.

[0049] Stents 800a-800d further include anti-migration fins (e.g., anti-migration fin 812a or anti-migration fin 812b). Generally, anti-migration fins can be loops located at the uncovered end (e.g., the proximal end) of the stent that protrude from the longitudinal plane of the stent. The anti-migration fins can be oriented to face toward the liver, distally, or a combination of both, as shown herein. The anti-migration fins reinforce the uncovered area of ​​the stent in the hepatic region, providing a more abrupt anti-migration feature relative to the uncovered surface. The uncovered surface alone often requires time (typically days to weeks, depending on the hepatic anatomy) to form a chronic anti-migration feature.

[0050] For example, Figure 8A shows a stent 800a according to some embodiments of the present disclosure. Stent 800a has a straight proximal end 808a with anti-migration fins 812a facing downstream (e.g., away from the hepatic duct).

[0051] For example, Figure 8B shows a stent 800b according to some embodiments of the present disclosure, which has a tapered proximal end 808b with anti-migration fins 812a facing downstream (e.g., away from the hepatic duct) similar to stent 800a.

[0052] For example, Figure 8C shows a stent 800c according to some embodiments of the present disclosure. Stent 800c has a straight proximal end 808a with anti-migration fins 812a facing both upstream and downstream.

[0053] For example, Figure 8D shows a stent 800d according to some embodiments of the present disclosure, which has a tapered proximal end 808b with anti-migration fins 812a facing both upstream and downstream.

[0054] As described above, the present disclosure provides embodiments of a stent usable in an endoscopic retrograde cholangiopancreatography (ERCP) procedure. The ERCP procedure may include advancing an endoscope through the mouth and stomach into the intestine. The endoscope may be advanced to a region of the intestine adjacent to the papilla of Vater. A guidewire may be advanced through the working channel of the endoscope to the papilla of Vater and into the common bile duct or pancreatic duct. A catheter loaded with a self-expanding stent may be advanced over the guidewire to access the common bile duct or pancreatic duct. The catheter may retract a sheath to allow the self-expanding stent to expand. The sheath may be partially retracted so that a first, or upstream, end of the stent is expandable within the common bile duct or pancreatic duct. After the upstream end is deployed, the sheath may be further retracted so that a second, or downstream, end of the stent is deployable. The downstream end of the stent may be deployed into the papilla of Vater, the intestine, or another region of the common bile duct or pancreatic duct. The cylindrical saddle region of the stent creates a fluid conduit or pathway between the common bile duct or pancreatic duct and the papilla of Vater or the intestine, or other regions of the common bile duct or pancreatic duct.

[0055] 9A and 9B show examples of body lumens that can be connected by the stents disclosed herein. In each region of the abdominal cavity, the stents described herein can be used to "span" or "connect" the common bile duct to the duodenum or the stomach to various locations within the biliary tree. In other words, FIGS. 9A and 9B show various locations within the abdominal cavity where a stent can be placed. In some embodiments, any of the stents disclosed herein can be placed at any of the locations shown in these figures. For example, any of the procedures shown in FIGS. 9A or 9B can be used in place of an ERCP procedure. In some cases, an ERCP procedure may be unsuccessful or impossible. In such cases, a stent can be placed through any of the routes shown in FIGS. 9A and 9B.

[0056] 9A, various regions within the abdominal cavity 902 of a patient 904 are shown, including, for example, the stomach 906, duodenum 908, pancreas 910, liver 912, common bile duct 914, hepatic duct 916, gallbladder 918, and cystic duct 920. Additionally, various stent placement routes are shown.

[0057] For example, Figures 9A and 9B show a choledochoduodenostomy 922 connecting the common bile duct 914 and the duodenum 908. For the choledochoduodenostomy, an endoscope can be advanced through the mouth and stomach 906 into the duodenum 908. A target site within the common bile duct 914 can be identified using ultrasound guidance or other guidance techniques. A needle or catheter device can be advanced through the endoscope to puncture the walls of the duodenum 908 and common bile duct 914. When using a needle to access the common bile duct 914, a guidewire can be placed and a catheter advanced over the guidewire to access the common bile duct 914. The catheter can be positioned with its upstream end or flange within the common bile duct 914 and its downstream end or flange within the duodenum 908, and a stent can be deployed to form a fluid conduit between the common bile duct 914 and the duodenum 908.

[0058] As another example, FIGS. 9A and 9B show a hepaticogastrostomy 924 connecting the hepatic cystic duct 920 and the stomach 906. To perform the hepaticogastrostomy 924, an endoscope can be inserted through the mouth and advanced into the stomach 906. A target site in the liver 912 can be identified using ultrasound guidance or other guidance techniques. A needle or catheter device can be advanced to puncture the stomach 906 and liver 912. A guidewire can be placed in the liver 912 (after needle access), and then a catheter loaded with a stent can be advanced over the guidewire. The catheter can be used to position the upstream end of the stent in the liver 912 and hepatic duct 916. The downstream end of the stent is deployed in the stomach 906. The stent can have an uncoated portion at the end of the stent that is positioned in the liver 912 and hepatic duct 916. For example, the upstream end deployed in the liver 912 can have an uncoated portion of approximately 3-4 cm. The uncoated portions at the ends of the stent facilitate the flow of bile from the liver and out through the interior space of the stent into the stomach 906. Pressure within the liver 912 assists in the drainage of bile from the liver 912 through the stent into the stomach 906. The downstream end of the stent deployed within the stomach 906 may be coated to reduce contact between bile and the wall of the stomach 906.

[0059] 9A and 9B illustrate a pancreaticogastrostomy 926 in which an endoscope can be inserted through the mouth and advanced into the stomach 906. A target site (e.g., a duct) within the pancreas 910 can be identified using ultrasound guidance or other guidance techniques. A needle or catheter device can be advanced through the endoscope to puncture the wall of the stomach 906 and the duct within the pancreas 910. A guidewire can be placed within the pancreas 910 (after needle access), and then a catheter loaded with a stent can be advanced over the guidewire. The catheter can be used to position the upstream end of the stent in the duct within the pancreas 910. The downstream end of the stent is deployed within the stomach 906, thereby forming a fluid conduit between the duct within the pancreas 910 and the stomach 906.

[0060] In some embodiments, the stents disclosed herein can be used for antegrade stent placement. Antegrade stent placement can be performed within the common bile duct 914 and the pancreas 910. Antegrade stent placement refers to a procedure in which the surgeon accesses the upstream common bile duct 914 (or a duct within the pancreas 910). The upstream common bile duct 914 can be accessed percutaneously (e.g., transhepatically) or under EDS guidance (e.g., transgastrointestinal methods targeting the intrahepatic or extrahepatic bile duct). After gaining access to the upstream bile duct, a guidewire is inserted and advanced downstream past the stricture and the papilla of Vater into the duodenum 908. The stent is then advanced antegrade over the wire, past the stricture and the papilla of Vater, until the downstream end of the stent is positioned within the duodenum 908. The sheath is retracted relative to the stent, releasing the downstream flange or double-walled flange. The sheath and stent can then be retracted together until the flange abuts the papilla of Vater, as indicated by resistance upon retraction. The sheath is then retracted relative to the stent, deploying the upstream flange into the common bile duct 914. A similar procedure can be used to place a stent antegrade into a duct within the pancreas 910 after gaining access to the upstream portion of the pancreas 910.

[0061] It should be noted that the foregoing is not an exhaustive description of exemplary procedures in which the stents described herein may be used. Rather, the foregoing is provided merely as an example and should not be construed as limiting the scope of the disclosure herein. The scope of the disclosure is defined by the appended claims and any claims in any subsequent application claiming priority from this application.

Claims

1. 1. A stent comprising:

1. A stent comprising: a body, the body having an elongated tubular configuration and a shortened configuration, wherein in the elongated tubular configuration, an upstream end of the body expands into an upstream configuration and a downstream end of the body expands into a flange configuration, the body comprising a cylindrical saddle region disposed between the upstream configuration and the flange configuration, the body comprising a channel extending helically around the periphery of the body, the channel being defined on the exterior of the body and mirrored on the interior of the body.

2. The stent of claim 1 , wherein the channels have a constant pitch along the length of the body.

3. The stent of claim 1 , wherein the pitch of the channels increases along the length of the body.

4. The stent of claim 3 , wherein the pitch increases along the length of the body from the upstream end to the downstream end.

5. The stent of any one of claims 1 to 4, wherein the width of the channel is wider at the upstream end of the body than at the downstream end of the body.

6. The stent of any one of claims 1 to 4, wherein the width of the channel is wider at the downstream end of the body than at the upstream end of the body.

7. The stent according to any one of claims 1 to 6, wherein the upstream structure comprises a flange or a flare.

8. 1. A stent comprising:

1. A stent comprising: a body, the body having an elongated tubular configuration and a shortened configuration, wherein in the elongated tubular configuration, an upstream end of the body expands into an upstream configuration and a downstream end of the body expands into a flange configuration, the body comprising a cylindrical saddle region disposed between the upstream configuration and the flange configuration, the body comprising a covering covering the downstream end of the body and the cylindrical saddle region, and the upstream configuration comprising a plurality of anti-migration fins disposed on an outer surface thereof.

9. The stent of any one of claims 8 to 12, wherein the plurality of anti-migration fins comprise wire fins arranged to radiate outward from the upstream structure.

10. The stent of any one of claims 8 to 12, wherein the plurality of anti-migration fins have tips that point toward the downstream end of the body.

11. 13. The stent of claim 8, wherein at least one of the plurality of anti-migration fins includes a tip pointing toward the downstream end of the body and at least another has a tip pointing toward the upstream end of the body.

12. The stent according to any one of claims 8 to 12, wherein the upstream structure comprises a flare.

13. 1. A stent comprising:

1. A stent comprising: a body, the body having an elongated tubular configuration and a shortened configuration, wherein in the elongated tubular configuration, an upstream end of the body expands into an upstream flange configuration and a downstream end of the body expands into a downstream flange configuration, the body having a cylindrical saddle region disposed between the upstream and flange structures, the body having a covering covering the downstream end of the body and the cylindrical saddle region, the cylindrical saddle region having a curve along the length of the body.

14. 14. The stent of claim 13, wherein the cylindrical saddle region comprises another curve along the axial direction of the body.

15. 15. The stent of claim 13 or 14, wherein the curve is closer to the upstream flange structure than to the downstream flange structure, or closer to the downstream flange structure than to the upstream flange structure.

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