STENTS, SYSTEMS AND METHODS FOR GASTROINTESTINAL TREATMENT - Patent application

Abstract

To provide stents, systems, and methods for improved gastrointestinal tract treatment.SOLUTION: In some embodiments, a stent may include a tubular scaffold having a first end opposite a second end with a lumen extending between the first end and the second end. The tubular scaffold may include a flared portion and an intermediate portion extending from the flared portion, wherein a first diameter of the flared portion is greater than a second diameter of the intermediate portion. The stent may further include a liner extending partially along a surface of the tubular scaffold, the liner being spaced from an anchor region of the flared portion to promote tissue ingrowth at the flared portion.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] The present invention relates to implantable medical devices, and more particularly to stents, systems and methods for treating the gastrointestinal tract. [Background technology]

[0002] Implantable medical devices, such as expandable stents, may be designed to provide a passageway for digestive matter, blood or other fluids to flow therethrough following a medical procedure. Additionally, some implantable medical devices incorporate geometries that aid in fistula repair, bypass surgery and / or anastomosis repair. These implantable medical devices may include radially expandable or self-expanding stents that may be implanted transluminally via an endoscope. Additionally, some stents may be implanted in various body cavities, such as the esophagus, digestive tract (e.g., intestines, stomach and colon), tracheobronchial tree, urinary tract, biliary tract, vasculature, etc.

[0003] For some stents, the compressibility and flexibility that aid in the placement of the stent may also cause the stent to migrate. For example, stents designed for placement in the esophagus or digestive tract may exhibit a tendency to migrate due to peristalsis, which is the involuntary contraction and relaxation of the muscles of the esophagus, intestine, and colon. Additionally, the generally moist and inherently lubricated environment of the esophagus, intestine, and colon further contributes to the tendency of the stent to migrate after deployment. One approach to reducing stent migration involves exposing bare metal to the body cavity tissue. The stent scaffold may provide a structure that promotes tissue ingrowth to promote a hyperplastic response.

[0004] Furthermore, some stents may be removed from or repositioned within the body lumen after deployment. One approach to reducing the force required to remove a stent involves coating a portion of the stent to reduce tissue ingrowth, thereby creating a physical barrier between the body lumen and the outer surface of the stent. However, such coated stents may be more susceptible to migration than bare stents. Summary of the Invention

[0005] The present invention, in various embodiments thereof, generally relates to stents, systems and methods for gastrointestinal treatment. In one or more embodiments, the stent may include a tubular scaffold having a first end opposite a second end, the tubular scaffold having a lumen extending between the first end and the second end. The tubular scaffold may include a flaring section, an intermediate section extending from the flaring section, the intermediate section having a diameter greater than a diameter of the intermediate section, and a liner extending partially along a surface of the tubular scaffold, the liner being spaced apart from an anchor region of the flaring section to promote tissue ingrowth at the flaring section. In some embodiments, the liner is disposed spaced apart from an intermediate anchor region of the intermediate section to promote tissue ingrowth at the intermediate section. In some embodiments, the intermediate anchor region is disposed at an extension portion of the intermediate section, the extension portion having a third diameter greater than a diameter of the intermediate section. In some embodiments, the liner is spaced apart from the extension portion to promote tissue ingrowth at the extension portion. In some embodiments, the anchor region is located along a tapered portion of the flaring section, the tapered portion extending away from a central longitudinal axis extending through the lumen. In some embodiments, the intermediate section has a substantially uniform diameter. In some embodiments, the flaring section has a first scaffold configuration and the intermediate section has a second scaffold configuration, the first scaffold configuration and the second scaffold configuration being different.

[0006] In one or more embodiments, the system may include a stent including a tubular scaffold having a first end opposite a second end, the tubular scaffold having a lumen extending between the first end and the second end. The tubular scaffold may include a flaring section and an intermediate section extending from the flaring section, the intermediate section having a first diameter greater than a second diameter of the intermediate section. The stent may further include a liner extending partially along a surface of the tubular scaffold, the liner spaced from an anchor region of the flaring section to promote tissue ingrowth at the flaring section. The system may further include a sheath extending from the second end of the tubular scaffold, the sheath having a proximal end opposite the distal end, the sheath having a lumen extending between the proximal end and the distal end. In some embodiments, the system may include a second stent coupled to a distal end of the sheath. In some embodiments, the second stent may include a second tubular scaffold and a second liner extending partially along a surface of the second tubular scaffold. In some embodiments, the second tubular scaffold may include a second flaring section and a second intermediate section extending from the second flaring section, the second flaring section having a first diameter that exceeds a second diameter of the second intermediate section, and the second liner being spaced from a second anchoring region of the second flaring section to promote tissue ingrowth at the second flaring section. In some embodiments, the liner is positioned away from an intermediate anchoring region of the intermediate section to promote tissue ingrowth at the intermediate section. In some embodiments, the anchoring region is located along a tapered portion of the flaring section, the tapered portion extending away from a central longitudinal axis extending through the lumen. In some embodiments, the intermediate section includes an expanding section having a third diameter that exceeds a diameter of the intermediate section. In some embodiments, the liner is spaced from the expanding section to promote tissue ingrowth at the expanding section. In some embodiments, the sheath includes a structural support element.

[0007] In one or more embodiments, the method may include deploying in a gastrointestinal (GI) tract of a patient a system including a stent having a tubular scaffold having a first end opposite a second end, the tubular scaffold having a lumen extending between the first end and the second end. The tubular scaffold may include a flaring section and an intermediate section extending from the flaring section, the intermediate section having a diameter greater than a diameter of the flaring section. The stent may further include a liner extending partially along a surface of the tubular scaffold, the liner being spaced from an anchor region of the flaring section, the anchor region being exposed to the GI tract to promote tissue ingrowth between the anchor region and the GI tract. The method may further include positioning the flaring section along one side of a target site of the GI tract and positioning the intermediate section directly adjacent the target site of the GI tract. In some embodiments, the method may further include determining a location of the target site of the GI tract corresponding to a GI tract leak. In some embodiments, the method may further include bypassing a portion of the GI tract with a sheath extending from a second end of the tubular scaffold, the sheath having a proximal end opposite the distal end and a lumen extending between the proximal and distal ends. In some embodiments, the method may include anchoring a second stent within the GI tract coupled to a distal end of the sheath.

[0008] One or more of the various features summarized above may be substituted, interchanged, combined, or replaced with other features summarized above for use with the medical systems and methods summarized above, and with the embodiments described in more detail below, and with other embodiments within the scope of the present invention.

[0009] Non-limiting embodiments of the present invention are described, by way of example, with reference to the accompanying drawings, which are not drawn to scale. In the figures, each identical or nearly identical illustrated component is typically represented by a single numeral. For clarity, not every component is labeled in every figure, nor are every component of each embodiment shown unless illustration is necessary to enable those skilled in the art to understand the disclosure. Furthermore, some of the drawings include cross-sectional views in the form of "slices" or "close-up" cross-sections that omit, for clarity, certain background lines or shapes that would otherwise be visible in a "true" cross-section. [Brief description of the drawings]

[0010] [Figure 1A] FIG. 2 is a side view of a stent according to an embodiment of the present invention. [Figure 1B] FIG. 2 is a side view of a stent according to an embodiment of the present invention. [Figure 1C] FIG. 2 is a side view of a stent according to an embodiment of the present invention. [Diagram 2] 1 illustrates a stent in a patient's GI tract in accordance with an embodiment of the present invention. [Diagram 3] FIG. 2 is a side view of a stent according to an embodiment of the present invention. [Figure 4A] 1A-1D are side views of a stent having various expansion portions in accordance with an embodiment of the present invention. [Figure 4B] 1A-1D are side views of a stent having various expansion portions in accordance with an embodiment of the present invention. [Figure 4C] 1A-1D are side views of a stent having various expansion portions in accordance with an embodiment of the present invention. [Figure 4D] 1A-1D are side views of a stent having various expansion portions in accordance with an embodiment of the present invention. [Figure 4E] 1A-1D are side views of a stent having various expansion portions in accordance with an embodiment of the present invention. [Figure 5A] FIG. 2 is a side view of a stent including a liner having recesses in accordance with an embodiment of the present invention. [Figure 5B] 5B is a cross-sectional view of the stent and liner of FIG. 5A in accordance with an embodiment of the present invention. [Figure 6A] FIG. 2 is a side view of a stent including a liner having recesses in accordance with an embodiment of the present invention. [Figure 6B] 6B is a cross-sectional view of a stent and liner similar to that of FIG. 6A in accordance with an embodiment of the present invention. [Figure 6C] FIG. 2 is a side view of a stent including a liner having recesses in accordance with an embodiment of the present invention. [Figure 7] 1 is a perspective view of a system according to an embodiment of the present invention. [Figure 8A] 8 is a cross-sectional view of the system of FIG. 7 placed within the GI tract during restrictive bariatric treatment in accordance with an embodiment of the present invention. [Figure 8B] 8 is a cross-sectional view of the system of FIG. 7 placed within the GI tract to treat a leak in accordance with an embodiment of the present invention. [Figure 9A] 1 is a cross-sectional view showing a system placed in the GI tract during restrictive obesity treatment according to an embodiment of the present invention. [Figure 9B] 1 is a cross-sectional view showing a system provided within the GI tract for treating a leak according to an embodiment of the present invention. [Figure 10] 1 is a cross-sectional view showing a system provided within the GI tract for treating a leak according to an embodiment of the present invention. [Figure 11] FIG. 2 is a side perspective view of a sheath according to an embodiment of the present invention. [Figure 12] FIG. 2 is a side perspective view of a sheath according to an embodiment of the present invention. [Figure 13] 1 is a side perspective view of a system according to an embodiment of the present invention. [Figure 14A] 1 is a side perspective view of a stent according to an embodiment of the present invention. [Figure 14B] 14B is a side cross-sectional view of the stent of FIG. 14A according to one embodiment of the present invention. [Figure 14C] 14B is a side cross-sectional view of the stent of FIG. 14A according to one embodiment of the present invention. [Figure 15A] FIG. 2 is a side view of a system according to an embodiment of the present invention. [Figure 15B] FIG. 15B is a side view of the system of FIG. 15A within the GI tract in accordance with an embodiment of the present invention. [Figure 16] 1 is a flow diagram of a method according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention is not limited to the specific embodiments described herein. The terms used herein are intended to describe specific embodiments only and are not intended to be limiting beyond the scope of the appended claims. Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by those skilled in the art of the present invention.

[0012] As previously mentioned, self-expanding metal stents (SEMS) are widely used throughout the gastrointestinal (GI) tract in a minimally invasive manner to treat numerous disease states, including but not limited to vascular lumen obstruction (e.g., stenosis due to neoplastic growth, surgical etiology, etc.) and GI bypass complications (e.g., treatment of leaks after bariatric surgery). SEMS can be removable or permanent depending on the condition being treated, with removability usually being dictated by the presence or absence of a durable coating. Permanent SEMS, when placed within the GI tract, may not have a coating that allows for vascular tissue ingrowth due to induced hyperplasia of the blood vessels. Ultimately, the SEMS becomes embedded in place as a result of tissue ingrowth.

[0013] As described in further detail herein, embodiments of the present invention provide stents, systems and methods for treating GI tract diseases, for resistance to migration, for a consistent and repeatable approach to treating multiple underlying diseases. In some embodiments, the stent may include a tubular scaffold having a first end opposite a second end, with a lumen extending between the first end and the second end. The tubular scaffold may include a flared section and an intermediate section extending from the flared section, the intermediate section having a diameter greater than a diameter of the flared section. The stent may further include a liner extending partially along a surface of the tubular scaffold, the liner being spaced from an anchor region of the flared section to promote tissue ingrowth at the flared section.

[0014] 1A, a stent 100 according to an embodiment of the present invention will be described in more detail. As shown, the stent 100 may include a tubular scaffold (hereinafter "scaffold") 102 having a first end 104 opposite a second end 106. The scaffold 102 may define a lumen 105 extending, for example, along a central longitudinal axis 108, between the first end 104 and the second end 106. When positioned within a body cavity, for example, within the GI tract of a patient, the first end 104 (in this case, the proximal end) may be positioned proximate to the patient's mouth.

[0015] Additionally, stent 100 may include one or more strut members 109 that form tubular scaffolding 102. Strut members 109 may extend helically, longitudinally, circumferentially, or otherwise along stent 100. Although Figure 1A shows strut members 109 extending generally along the entire length of stent 100, in other embodiments, strut members 109 may extend only along a portion of stent 100.

[0016] As further shown, the scaffold 102 may include a flange or flared portion 110 connected to or integrally formed with an intermediate portion 112. In some embodiments, a first diameter "D1" of the flared portion 110 may exceed a second diameter "D2" of the intermediate portion 112. As shown, the intermediate portion 112 may have a generally uniform diameter along its entire length. The flared portion 110 may include an angled portion 114 extending away from the central longitudinal axis 108. In some embodiments, the angled portion 114 is an intersection between the flared portion 110 and the intermediate portion 112.

[0017] In some embodiments, the stent 100 may be balloon or self-expanding. Examples of self-expanding stents may include stents having one or more strut members 109 that combine to form a rigid and semi-rigid stent structure or a rigid or semi-rigid stent structure. For example, the strut members 109 may be one or more wires or filaments that are braided, wrapped, entangled, interwoven, woven, knitted, looped (e.g., in a bobbinette fashion), or the like, to form the scaffold 102. Alternatively, the stent 100 may be a monolithic structure formed of a cylindrical tubular member, such as a single cylindrical tubular laser-cut Nitinol tubular member, with the remaining portions of the tubular member forming the strut members 109. Openings or gaps through the wall of the stent 100 may be defined between adjacent strut members 109.

[0018] Stent 100 may be constructed from a variety of non-limiting materials. For example, if balloon or self-expanding, stent 100 may be constructed from metals (e.g., Nitinol, Elgiloy, stainless steel, cobalt chrome, positive temperature coefficient of resistivity, etc.). In other examples, stent 100 may be constructed from polymeric materials (e.g., polyethylene terephthalate, poly(methyl methacrylate)). In yet other examples, stent 100 may be constructed from a combination of metallic and polymeric materials. In still other examples, stent 100 may include bioabsorbable and / or biodegradable materials (e.g., poly(lactic-co-glycolic acid) polymers).

[0019] As shown in FIG. 1B, the stent 100 may include a liner 120 extending between the first end 104 and the second end 106. The liner 120 may be provided to prevent tissue ingrowth along the scaffold 102 in certain areas as well as to maintain a passageway through the stent 100. In the non-limiting embodiment shown, the liner 120 may be formed on the outer surface 122 of the scaffold 102. However, the liner 120 may be formed only partially along the exterior of the scaffold 102, as described in more detail herein. In yet other embodiments, the liner 120 may be formed along the inner surface 124 of the scaffold 102. In other embodiments, the liner 120 may be formed along both the outer and inner surfaces 124 of the scaffold.

[0020] In various embodiments, the liner 120 may be a polymeric material such as silicone, polyurethane, polyvinylidene difluoride (PVDF), Chronoflex®, or similar biocompatible polymer blends. In yet other embodiments, the liner 120 may include a ciliated coating (not shown) along its inner surface. As shown, the liner 120 may extend between the strut members 109, thereby filling any spaces between the strut members 109 of adjacent scaffolding 102. A liner may be understood to be a coating in which a portion of the coating is coupled to at least a portion of the stent and a portion of the coating may be floating relative to the stent.

[0021] In some embodiments, the liner 120 is spaced from the anchor region 125 of the flaring portion 110 to promote tissue ingrowth between the GI tract and the anchor region 125 of the flaring portion 110. For example, the liner 120 at the anchor region 125 may extend radially inward toward the central longitudinal axis 108 such that the liner 120 does not generally contact the inner surface 124 of the scaffold 102. As a result, the anchor region 125 may promote or allow tissue ingrowth to secure the flaring portion 110 in place within the GI tract.

[0022] In some embodiments, the liner 120 may include an elastic material component configured to stretch radially inward, for example, as tissue grows through interstices of the scaffold 102 in the anchoring regions 125. The liner 120 may flex, stretch, etc. radially inward in response to an inward force (e.g., tissue ingrowth) acting on the liner 120.

[0023] In other embodiments, it may be desirable to limit the amount of inward deflection of the liner 120. For example, the liner 120 may define a lumen extending into the liner 120 that is designed to allow food and other digestible materials or food or other digestible materials to flow therethrough. Thus, in some cases, it may be desirable to design the liner 120 to maintain the passageway defined by the lumen 105. In other words, in some cases, it may be desirable to prevent or minimize the amount of radial closure of the liner 120. In some cases, the liner 120 may include reinforcing filaments (e.g., fibers) embedded within the material of the liner 120 that may be tensioned after stretching the material of the liner 120 to a threshold amount to prevent further stretching of the liner 120. In some cases, the reinforcing filaments may be arranged longitudinally, circumferentially, helically, randomly, or otherwise.

[0024] Examples of liners and stent / liner configurations may include, but are not limited to, those shown and described in U.S. Patent Application Publication No. 2018 / 0250118, entitled "Esophageal Stent Including an Inner Liner," filed March 1, 2018, and U.S. Patent Application Publication No. 2018 / 0280167, entitled "Retrievable Stent System," filed March 27, 2018, both of which are incorporated by reference into this application for all purposes.

[0025] As shown in FIG. 1C, the scaffold 102 may include multiple portions that are joined together. For example, the middle section 112 may include a first component 128 connected to a second component 130. The first component 128 and the second component 130 may be joined together using any type of attachment means. In the non-limiting embodiment shown, the strut members 109 of the first component 128 may be arranged in a first configuration, such as a weave, and the strut members 109 of the second component 130 may be arranged in a second configuration, such as a braid. In some embodiments, the first component 128 and the second component 130 may have the same or different weave patterns. The embodiments herein are not limited in this context.

[0026] FIG. 2 illustrates the use of a stent 100 within a patient's GI tract 132, according to an embodiment of the present invention. In this non-limiting example, the GI tract 132 may include a staple line 131, for example, as a result of a sleeve gastrectomy. As shown, the stent 100 may be deployed at a target site 134 of the GI tract, thereby addressing a leak, perforation, or tear along the staple line 131. As shown, the flaring portion 110 may be positioned within a proximal portion of the GI tract 132 (in this case, the patient's esophagus), and the intermediate portion 112 may extend further down within the GI tract 132 (in this case, the stomach remnant). An anchor region 125 of the flaring portion 110 may be provided adjacent the GI tract 132 to promote tissue ingrowth between the GI tract 132 and the flaring portion 110. Meanwhile, the liner 120 along the intermediate portion 112 may be positioned directly adjacent the target site 134 of the GI tract to prevent or minimize leakage.

[0027] 3 illustrates a stent 300 according to an embodiment of the present invention. Stent 300 may be the same or similar in many respects to previously described stent 100. Thus, for the sake of brevity, only certain aspects of stent 300 will be described below.

[0028] As shown, the stent 300 may include a scaffolding 302 having a first end 304 opposite a second end 306. The scaffolding 302 may define a lumen 305 extending between the first end 304 and the second end 306, for example, along a central longitudinal axis 308. The scaffolding 302 may include a flared portion 310 connected to or formed integrally with an intermediate portion 312. The flared portion 310 may include an angled portion 314 extending away from the central longitudinal axis 308. In some embodiments, the angled portion 314 connects the flared portion 310 to the intermediate portion 312.

[0029] As shown, the intermediate section 312 may include an intermediate anchor region 335, which is a bare portion of the scaffold 302 to promote tissue ingrowth between the intermediate section 312 and the GI tract. As shown, the liner 320 extending along the scaffold 302 may be spaced apart from the intermediate anchor region 335 to promote tissue ingrowth. In some embodiments, the liner 320 at the intermediate anchor region 335 may extend radially inward toward the central longitudinal axis 308. The liner 320 may be spaced apart from the anchor region 325 of the flaring section 310 to promote tissue ingrowth between the GI tract and the flaring section 310. In some embodiments, the anchor region 325 is located along the angled portion 314. When inserted into a patient, the anchor region 325 of the flared portion 310 may be positioned along one side (e.g., the upper side) of a target site of the GI tract (not shown), while the intermediate anchor region 335 of the intermediate portion 312 may be positioned adjacent to, or adjacent to or below, the target site of the GI tract to isolate a leak at the target site of the GI tract.

[0030] 4A illustrates a stent 400 in accordance with an embodiment of the present invention. Stent 400 may be the same or similar in many aspects to the previously described stents 100 and / or 200. Thus, for the sake of brevity, only certain aspects of stent 400 are described below.

[0031] As shown, the stent 400 may include a scaffolding 402 having a first end 404 opposite a second end 406. The scaffolding 402 may define a lumen 405 extending between the first end 404 and the second end 406, for example, along a central longitudinal axis 408. A liner 420 may be provided along the scaffolding 402. The scaffolding 402 may include a flared portion 410 connected to or integrally formed with an intermediate portion 412. In some embodiments, a first diameter "D1" of the flared portion 410 may exceed a second diameter "D2" of the intermediate portion 412. The flared portion 410 may include an angled portion 414 extending away from the central longitudinal axis 408. In some embodiments, the angled portion 414 joins the flared portion 410 to the intermediate portion 412.

[0032] As shown, the intermediate section 412 may include an intermediate anchor region 435, which may be a bare spot / area along the scaffold 402 to promote tissue ingrowth between the intermediate section 412 and the GI tract. In some embodiments, the intermediate anchor region 435 may be provided at an extended portion 440 of the intermediate section 412. As shown, the extended portion 440 may have a third diameter "D3" that exceeds D2 of the intermediate section 412. The extended portion 440 may have a curvature, e.g., bulging radially outward from the intermediate section 412, such that the third diameter D3 is the maximum diameter of the curvature. In some embodiments, D3 may also exceed D1 of the flared section 410. In other embodiments, D3 is equal to or less than D1. The embodiments herein are not limited in this context.

[0033] As further shown, the liner 420 extending along the scaffold 402 may be spaced from the extension portion 440 to promote tissue ingrowth along certain portions of the middle section 412, such as the middle anchor region 435. In some embodiments, the liner 420 located radially inward from the extension portion 440 may be curved or extend toward the central longitudinal axis 408. In other embodiments, the liner 420 may be generally straight at the extension portion 440, as shown. When inserted into a patient, the anchor region 425 of the flaring portion 410 may be positioned along one side (e.g., the upper portion) of a target site of the GI tract (not shown), while the extension portion 440 of the middle section 412 may be positioned at or below the target site of the GI tract. The anchor region 425 may secure the flaring portion 410 within the GI tract, while the extension portion 440 may interact with the target site of the GI tract to promote a hyperplastic response from tissue of the GI tract. In some embodiments, a distal portion 442 of the intermediate section 412 may extend from the dilated portion 440 to function as a conduit to form a bypass at a target site in the GI tract.

[0034] It will be apparent that extension portion 440 may have a variety of different configurations. For example, extension portion 440 in Fig. 4A may have a generally spherical cross-section, extension portion 440B in Fig. 4B may have a generally trapezoidal cross-section, extension portion 440C in Fig. 4C may have a generally pentagonal cross-section, and extension portion 440D in Fig. 4D may have a generally chordal cross-section. The embodiments herein are not limited in this context.

[0035] Additionally, it will be apparent that the length of the various extension portions 440A-440E may be altered to affect the amount of interaction between the intermediate anchor region 435 and the GI tract. For example, as shown in FIG. 4E, the length "L1" of extension portion 440E may be increased relative to the overall length "L2" of intermediate section 412. As will be apparent, GI tract tissue ingrowth generally increases as length L1 increases.

[0036] 5A-5B, the liner 520 of the stent 500 according to an embodiment of the present invention will be described in more detail. As shown, the liner 520 may have a non-circular cross-section to promote tissue ingrowth between the scaffold 502 of the stent 500 and the GI tract. In this embodiment, the liner 520 may include a recess 550 spaced from the inner surface 524 of the scaffold 502. The recess 550 may provide an intermediate anchoring region 535 of the scaffold 502. In some embodiments, the intermediate anchoring region 535 may be provided in an expanded portion 540 of the intermediate section 512. In other embodiments, the intermediate section 512 may have a substantially constant diameter along its entire length.

[0037] 6A-6B, the liner 620 of the stent 600 may include a plurality of recesses 650 spaced apart from the inner surface 624 of the scaffolding 602 of the stent 600. The recesses 650 (different configurations are shown in FIGS. 6A and 6B as non-limiting examples) may be spaced apart circumferentially along the liner 620, and may provide a plurality of intermediate anchoring regions 635 along the scaffolding 602 to promote tissue ingrowth between the scaffolding 602 and the intermediate section 612. In some embodiments, the intermediate anchoring regions 635 may be provided at an extended portion 640 of the intermediate section 612. In other embodiments, the intermediate section 612 may have a substantially constant diameter along its entire length.

[0038] 6C, the extension portion 640 of the middle section 612 may not include a liner 620. Instead, the extension portion 640 remains exposed to promote hyperplastic tissue growth 627 between the body cavity (not shown) and the exposed portion of the scaffold 602. The hyperplastic tissue growth 627 may act as a seal to form a continuous channel through the interior of the scaffold 602.

[0039] Turning now to Figure 7, a system 701 according to an embodiment of the present invention will be described in more detail. As shown, system 701 may include a stent 700 having a tubular scaffolding (hereinafter "scaffolding") 702. Stent 700 may be the same or similar in many aspects to stents 100, 300, 400, 500 and 600 previously described. Thus, for the sake of brevity, only certain aspects of stent 700 will be described below.

[0040] As shown, the stent 700 may include a first flared portion 710 at a first end 704 and a second flared portion 711 at a second end 706. An intermediate portion 712 is located between the first flared portion 710 and the second flared portion 711. As shown, the intermediate portion 712 may have a reduced diameter compared to the diameters of the first flared portion 710 and the second flared portion 711. As further shown, the stent 700 may include a liner 720 disposed along a surface of the scaffold 702.

[0041] In some embodiments, the sheath 760 may be coupled to the second end 706 of the stent 700. The sheath 760 may be a flexible tube having a proximal end 762 and a distal end 764, where the sheath 760 defines a lumen extending between the proximal end 762 and the distal end 764. Without limitation, the sheath 760 may be silicone, UE, PTFE, ePTFE, Chronoflex, PMMA, PVDF, or the like.

[0042] As further shown, the system 701 may include a second stent 765 coupled to a distal end 764 of the sheath 760. In some embodiments, the second stent 765 may include a second tubular scaffold (hereinafter, "second scaffold") 768 defined by a plurality of stent members 769 arranged in any type of configuration. The second scaffold 768 of the stent 765 may have a constant diameter or a varying diameter. For example, in the latter case, the second scaffold 768 may include a first flared portion 770 connected to or integrally formed with a second intermediate portion 772. In some embodiments, the second tubular scaffold 768 may include a second flared portion 773 extending from an opposite side of the second intermediate portion 772. In some embodiments, the diameters of the first flared portion 770 and the second flared portion 773 of the second scaffold 768 exceed the diameter of the second intermediate portion 772. The embodiments herein are not limited in this context.

[0043] Although not shown, a second liner may extend along a surface (e.g., inner and / or outer surface) of the second scaffold 768. In some embodiments, the second liner may be spaced apart from the second scaffold 768 at one or more second anchor regions to promote tissue ingrowth between the second scaffold 768 and the GI tract of the patient. In other embodiments, no liner is present along the second scaffold 768.

[0044] 8A-8B illustrate an example of the use of system 701 within a patient's GI tract 732, in accordance with an embodiment of the present invention. Without limitation, FIG. 8A illustrates system 701 disposed within GI tract 732 for restrictive bariatric treatment. As shown, sheath 760 may form a bypass for a portion of GI tract 732. FIG. 8B illustrates system 701 used for treatment of a gastrocutaneous fistula. As shown, stent 700 may be positioned within a proximal portion of GI tract 732, while sheath 760 may extend further down within GI tract 732. An anchor region 725 of flaring portion 710 may be disposed immediately adjacent the interior of GI tract 732 to promote tissue ingrowth between GI tract 732 and flaring portion 710.

[0045] A second stent 765 coupled to the sheath 760 may be positioned within the GI tract 732, such as below the pylorus portion 780 thereof. In some embodiments, the second stent 765 may include one or more second anchoring regions (not shown) to promote tissue growth between the GI tract 732 and the second scaffold 768.

[0046] In some embodiments, the system 701 may not include a second stent connected to the sheath 760. For example, as shown in FIGS. 9A-9B, the stent 700 may be placed in a proximal portion of the GI tract 732, while the sheath 760 may extend further down into the GI tract 732. In some embodiments, the sheath 760 may extend beyond the pylorus portion 780 of the GI tract 732. Without limitation, FIG. 9A illustrates the system 701 in the GI tract 732 for restrictive bariatric treatment, while FIG. 9B illustrates the system 701 used to treat leaks, such as enteric, extraintestinal, gastrocutaneous, and combined fistulas. As shown in FIG. 9A, the sheath 760 may extend further along the GI tract 732, for example, into the duodenum 782 (also known as a gastrojejunal bypass (GJ) procedure).

[0047] Turning now to FIG. 10, a system 701 for use within a patient will be described according to another embodiment of the present invention. Without limitation, the system 701 may be particularly useful in restrictive bariatric treatment, for example, using a gastrojejunostomy. As shown, the stent 700 may be positioned within a proximal portion of the GI tract 732 while the sheath 760 may extend through the stomach 781 of the patient. A second stent 765 coupled to the sheath 760 may be positioned within the GI tract 732, for example, between both the stomach 781 and the duodenum 782 extending from the stomach 781. As shown, the second scaffold 768 of the second stent 765 may be positioned such that the first flaring portion 770 is positioned within the stomach 781 while the second flaring portion 773 is positioned within the duodenum 782. The second intermediate section 772 may extend between the first flaring section 770 and the second flaring section 773 to form a bypass between the stomach 781 and the duodenum 782. Although not shown in FIG. 10 , a second liner 775 may extend through the second intermediate section 772. Additionally, one or more anchor regions may be located along the first flaring section 770, the second flaring section 773, and / or the second intermediate section 772 to secure the second stent 765 in place between the stomach 781 and the duodenum 782.

[0048] 11 illustrates a sheath 1160 according to an embodiment of the present invention. The sheath 1160 may include a structural support element 1183 extending along the entire length of the sheath 1160, for example between the proximal end 1162 and the distal end 1164. In some embodiments, the structural support element 1183 may be a spiral or helical rib extending along the sheath 1160. The structural support element 1183 may be disposed along the inner and / or outer surface of the sheath 1160, or may be embedded within the sheath 1160, for example between one or more layers thereof. The structural support element 1183 may provide rigidity to the sheath 1160. In a non-limiting embodiment, the structural support element 1183 may be fabricated from a reinforced thickened or tubular hollow solid strip of a natural or high density polymer. Additionally or alternatively, the structural support element may include a section of a harder material, for example Nitinol, stainless steel, etc.

[0049] In FIG. 12, a sheath 1260 according to an embodiment of the present invention is shown. The sheath 1260 may include a flexible section 1284 disposed between a proximal end 1262 and a distal end 1264. In some embodiments, the flexible section 1284 includes a length of corrugation arranged as a series of ridges 1285 and grooves 1286. The flexible section 1284 may provide flexibility to the sheath 1260. In some embodiments, the flexible section 1284 may include one or more structural support members. In a non-limiting embodiment, the series of ridges 1285 and grooves 1286 of the corrugation may correspond to a number of ripples formed in the sheath 1260. The series of ridges 1285 and grooves 1286 may be formed by placing strips of alternating density or thickness next to each other. Alternatively or additionally, the series of ridges 1285 and grooves 1286 may be formed by placing strips of alternating polymer layers having different elastic strips next to each other. Alternatively, or in addition, the series of ridges 1285 and grooves 1286 may be formed by recessed ribs made of a material such as Nitinol, stainless steel, or the like.

[0050] Turning now to Figure 13, a system 1301 according to an embodiment of the present invention will be described. System 1301 may be the same or similar in many respects to the previously described system 701. Thus, for the sake of brevity, only certain aspects of system 1301 will be described below.

[0051] As shown, the system 1301 may include a first stent 1300 and a second stent 1365 connected by a first sheath 1360. For example, a first end 1362 of the first sheath 1360 may be connected to the first stent 1300, while a second end 1364 of the first sheath 1360 may be connected to the second stent 1365. In some embodiments, the first sheath 1360 may be a flexible conduit defining a lumen. Without limitation, the first sheath 1360 may include one or more structural support elements and / or flexible portions.

[0052] The system 1301 may further include a second sheath 1388 extending from the second stent 1365. The second sheath 1388 may include a proximal end 1389 coupled to the second stent 1365 and a distal end 1390 extending further into the patient's GI tract. The second sheath 1388 may be the same as or similar to the first sheath 1360. In other embodiments, the second sheath 1388 may be different than the first sheath 1360, for example, depending on the location of use within the patient's GI tract. Although not shown, it will be apparent that additional stents may be connected to the second sheath 1388, for example, at its distal end 1390.

[0053] As shown, the first stent 1300 may include a first flared section 1310 at a first end 1304 and a second flared section 1311 at a second end 1306. Located between the first flared section 1310 and the second flared section 1311 is an intermediate section 1312. As shown, the intermediate section 1312 may have a reduced diameter compared to the diameters of the first flared section 1310 and the second flared section 1311. A first sheath 1360 may extend from and be connected to the second end 1306 of the first stent 1300.

[0054] In some embodiments, the first stent 1300 may include a liner 1320 disposed along a surface of the scaffold 1302. The liner 1320 may be spaced apart from anchor regions 1325 along the scaffold 1302 to promote tissue ingrowth in the GI tract. Without limitation, the anchor regions 1325 may be disposed along the first flaring section 1310, the second flaring section 1311, and / or the intermediate section 1322.

[0055] As further shown, in some embodiments, the second stent 1365 may be the same or similar to the first stent 1300. For example, the second scaffold 1368 of the second stent 1365 may include a first flared portion 1370 and a second flared portion 1373 connected by a second intermediate portion 1372. In some embodiments, the second liner 1375 may extend along a surface (e.g., an inner surface and / or an outer surface) of the second scaffold 1368. The second liner 1375 may be spaced apart from the second scaffold 1368 at one or more second anchor regions 1379 to promote tissue ingrowth between the second scaffold 1368 and the GI tract. Without limitation, the second anchor regions 1379 may be disposed along the first flared portion 1370, the second flared portion 1373, and / or the second intermediate portion 1372.

[0056] 14A-14C, a stent 1400 according to an embodiment of the invention will be described in more detail. As shown, a scaffolding 1402 of the stent 1400 has a first end 1404 opposite a second end 1406, and the scaffolding 1402 may define a lumen extending between the first end 1404 and the second end 1406, for example along a central longitudinal axis 1408.

[0057] The stent 1400 may include one or more strut members 1409 (FIG. 14A) that form a tubular scaffolding 1402. The strut members 1409 may extend helically, longitudinally, circumferentially, or otherwise along the stent. As further shown, the scaffolding 1402 may include a first flared / flange portion 1410 and a second flared / flange portion 1411 connected to or integrally formed with an intermediate portion 1412. In some embodiments, the diameter of the first flared portion 1410 and / or the second flared portion 1411 may exceed the diameter of the intermediate portion 1412. As shown, the intermediate portion 1412 may have a generally uniform diameter along its entire length.

[0058] In some embodiments, the stent 1400 may be balloon or self-expanding. Examples of self-expanding stents may include stents having one or more strut members 1409 that combine to form a rigid and semi-rigid stent structure or a rigid or semi-rigid stent structure. For example, the strut members 1409 may be wires or filaments that are braided, wrapped, entangled, interwoven, woven, knitted, looped (e.g., in a bobbinette fashion), etc., to form the stent structure. Alternatively, the stent 1400 may be a monolithic structure formed of a cylindrical tubular member, such as a single cylindrical tubular laser cut Nitinol tubular member, with the remaining portions of the tubular member forming the strut members 1409. Openings or gaps through the wall of the stent 1400 may be defined between adjacent strut members 1409.

[0059] Stent 1400 in the examples disclosed herein may be constructed from a variety of materials. For example, if balloon or self-expanding, stent 1400 may be constructed from metal (e.g., Nitinol, Elgiloy, etc.). In other examples, stent 1400 may be constructed from a polymeric material (e.g., PET). In yet other examples, stent 1400 may be constructed from a combination of metallic and polymeric materials. In still other examples, stent 1400 may include bioabsorbable and / or biodegradable materials.

[0060] As further shown, the stent 1400 may include a liner 1420 extending partially along the scaffolding 1402. In the non-limiting embodiment shown, the liner 1420 may be formed along an inner surface 1424 of the scaffolding 1402. In other embodiments, the liner 1420 may be formed along an outer surface 1422 of the scaffolding 1402. In yet other embodiments, the liner 1420 may be formed along both the outer surface 1422 and the inner surface 1424 of the scaffolding 1402.

[0061] Additionally, the liner 1420 may include one or more layers provided with the liner 1420 along the scaffold 1402 to prevent or minimize tissue ingrowth. In some embodiments, the liner 1420 may be an elastomeric or non-elastomeric material. As shown, the liner 1420 may extend between the strut members 1409, thereby filling any space between adjacent strut members 1409 of the scaffold 1402.

[0062] In some embodiments, the liner 1420 is connected to the scaffold 1402 along the first flared / flange portion 1410 and the second flared / flange portion 1411 and is spaced apart from the anchor region 1425 of the middle portion 1412 to promote tissue ingrowth between the GI tract and the scaffold 1402 in the middle portion 1412. For example, the liner 1420 in the anchor region 1425 may extend radially inward toward the central longitudinal axis 1408 such that the liner 1420 is generally free of contact with the inner surface 1424 of the scaffold 1402 along the middle portion 1412. As shown in FIG. 14B, the anchor region 1425 may extend generally along the entire length of the middle portion 1412. As shown in FIG. 14C, the anchor region 1425 may extend along only a portion of the middle portion 1412. It will be apparent that the dimensions of anchor region 1425 may be selected to increase or decrease the amount of tissue ingrowth between intermediate portion 1412 and the GI tract, although the embodiments herein are not limited in this context.

[0063] 15A-15B, a system 1501 according to an embodiment of the present invention will be described. As shown, the system 1501 may include a stent 1500 coupled to a sheath 1560. The stent 1500 may be the same or substantially the same as the stent 1400 described above. As shown in FIG. 15B, the stent 1500 may be used to extend the sheath 1560 further into the duodenum 1582 to connect the stomach 1581 and the duodenum 1582 of the patient. More specifically, the scaffold 1502 of the stent 1500 may be positioned such that the first flaring portion 1510 is positioned within the stomach 1581 while the second flaring portion 1511 is positioned within the duodenum 1582. The intermediate portion 1512 may extend between the first flaring portion 1510 and the second flaring portion 1511 to form a bypass between the stomach 1581 and the duodenum 1582 .

[0064] A liner 1520 (FIG. 15A) may extend through the intermediate portion 1512. The liner 1520 may be spaced from the inner surface 1522 of the scaffold 1502 to form one or more anchoring regions 1525 along the intermediate portion 1512. The anchoring regions 1525 may promote tissue growth to secure the stent 1500 in place between the stomach 1581 and the duodenum 1582 through the pyloric valve 1587, for example, as shown in FIG.

[0065] In some embodiments, the sheath 1560 may be a length of corrugated material extending through the duodenum 1582. The corrugated material may be defined by a series of ridges 1585 and grooves 1586, which may provide flexibility to the sheath 1560 to traverse the duodenum 1582. In some embodiments, the corrugated material may act as a liner to inhibit nutrient intake, for example, to treat diabetes and promote weight loss, or to treat diabetes or promote weight loss.

[0066] 16 is a flow diagram of a method 1600 according to an embodiment of the invention. At block 1601, the method 1600 may include determining a location of a target site in the GI tract corresponding to a GI tract defect.

[0067] At block 1603, the method 1600 comprises deploying a system within the patient's GI tract, the system including a stent including a tubular scaffold including a flaring portion and an intermediate portion extending from the flaring portion, the tubular scaffold may further include a liner extending partially along a surface of the tubular scaffold, the liner spaced from an anchor region of the flaring portion, the anchor region exposed to the GI tract to promote tissue ingrowth between the anchor region and the GI tract.

[0068] At block 1605, the method 1600 may include placing the flared section along one side of the target site of the GI tract and placing the intermediate section directly adjacent to the target site of the GI tract. In some embodiments, mucosal abrasion of an insertion site in the GI tract is used to promote tissue ingrowth between one or more regions or portions of the stent, such as the anchor region and the GI tract, such as to inhibit migration of the stent from the target site. In some embodiments, the method 1600 may further include forming a bypass of a portion of the GI tract with a sheath extending from a second end of the tubular scaffold, the sheath having a proximal end opposite the distal end and a lumen extending between the proximal end and the distal end. In some embodiments, the method 1600 may further include anchoring a second stent coupled to a distal end of the sheath within the GI tract. In some embodiments, mucosal peeling of an insertion site in the GI tract is used to promote tissue ingrowth between one or more regions or portions of the second stent, such as the anchor region and the GI tract, such as to inhibit migration of the second stent from the target site.

[0069] The stents described herein may be fabricated from metals, metal alloys, polymers (some examples are disclosed below), metal-polymer composites, ceramics, combinations thereof, or the like, or other suitable materials. 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), polyvinylchloride (PVC), polyether-esters (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® available from Bayer or Elf Atochem). available from Atochem), elastomeric polyamides, block polyamide / ethers, polyether block amides (e.g., PEBA available under the trade name PEBAX), ethylene vinyl acetate copolymer (EVA), silicones, polyethylene (PE), Marlex high density polyethylene, Marlex low density polyethylene, linear low density polyethylene (e.g., REXELL), polyesters, polybutylene terephthalate (PBT), polyethylene terephthalate (PET).terephthalate), polytrimethylene terephthalate, polyethylene naphthalate (PEN), polyetheretherketone (PEEK), polyimide (PI), polyetherimide (PEI), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), polyparaphenylene terephthalamide (e.g., KEVLAR®), polysulfone, nylon, nylon-12 (e.g., GRILAMID® available from EMS American Grilon), perfluoro(propyl vinyl ether) (PFA), ethylene vinyl alcohol, polyolefins, polystyrene, epoxies, polyvinylidene chloride (PVdC), poly(styrene-b-isobutylene-b-styrene) (e.g., SIBS and SIBS 50A), polycarbonate, ionomer, biocompatible polymer, other suitable materials, or mixtures, combinations, copolymers, polymer / metal composites, etc. In some embodiments, the sheath can be blended with a liquid crystal polymer (LCP). For example, the blend can include up to about 6 percent LCP.

[0070] Examples of suitable metals and metal alloys include stainless steels, such as 304V, 304L, and 316LV stainless steel; mild steel; nickel-titanium alloys, such as linear elastic and superelastic Nitinol or linear elastic or superelastic Nitinol; other nickel alloys, such as nickel-chromium-molybdenum alloys (e.g., UNS: N06625, such as INCONEL® 625; UNS: N06022, such as HASTELLOY® C-22®; UNS: N06024, such as HASTELLOY® C-22®; Nickel-copper alloys (e.g., UNS:N10276, such as HASTELLOY® C276®, other HASTELLOY® alloys, etc.), nickel-cobalt alloys (e.g., UNS:N04400, such as MONEL® 400, NICKELVAC® 400, NICORROS® 400, etc.), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS:R30035, such as MP35-N®), nickel-molybdenum alloys (e.g., HASTELLOY® ALLOY®), B2®), other nickel-chromium alloys, other nickel-molybdenum alloys, other nickel-cobalt alloys, other nickel-iron alloys, other nickel-copper alloys, other nickel-tungsten or tungsten alloys, and the like; cobalt-chromium alloys; cobalt-chromium-molybdenum alloys (e.g., UNS:R30003, such as ELGILOY®, PHYNOX®); platinum-rich stainless steels; titanium; combinations thereof, and the like; or any other suitable material.

[0071] In at least some embodiments, some or all of the stents described herein and other components of the stents may be doped with, fabricated from, or otherwise include radiopaque materials. Radiopaque materials are considered to be materials capable of producing a relatively bright image on a fluoroscopy screen or other imaging modality during a medical procedure. This relatively bright image aids the user in determining the location of the stent. Examples of radiopaque materials may include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloys, polymeric materials with radiopaque fillers, and the like. Additionally, other radiopaque marker bands and coils or other radiopaque marker bands or coils may be incorporated into the stent design to achieve the same results.

[0072] In some embodiments, a degree of Magnetic Resonance Imaging (MRI) compatibility is imparted to the stents described herein. For example, the stent and other components of the stent or portions thereof may be made of materials that do not substantially distort images or create substantial artifacts (e.g., gaps in the image). The stent may be made of materials that can be imaged by an MRI machine. Materials that exhibit these characteristics include, for example, tungsten, cobalt-chromium-molybdenum alloys (e.g., UNS:R30003, such as ELGILOY®, PHYNOX®, etc.), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS:R30035, such as MP35-N®), Nitinol, and the like.

[0073] Some embodiments may be described using the terms "coupled" and "connected," along with their derivatives. These terms are not intended to be synonyms for each other. For example, some embodiments may be described using the terms "connected" and / or "coupled" to indicate that two or more elements are in direct physical or electrical contact with each other. However, the term "coupled" may also mean that two or more elements are not in direct contact with each other, but still cooperate or interact with each other.

[0074] As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms thereof unless the context clearly dictates otherwise. It will be further understood that the terms "comprise" and / or "comrising" or "includes" and / or "including" as used herein specify the presence of stated features, regions, steps, elements and / or components, but do not exclude the presence or addition of one or more of those other features, regions, integers, steps, operations, elements, components and / or groups.

[0075] Furthermore, the terms "substantially" or "substantially" and "approximately" or "approximately" can be used interchangeably in some embodiments and can be described using any relative measure acceptable to those skilled in the art. For example, these terms can serve as a comparison to a reference parameter to indicate a deviation that still provides the intended function. Without being limited thereto, deviations from the reference parameter can be, for example, amounts of less than 1%, less than 3%, less than 5%, less than 10%, less than 15%, less than 20%, etc.

[0076] Although specific embodiments have been shown and described herein, it is understood that any configuration calculated to achieve the same purpose may be substituted for the specific embodiment shown. The present invention is intended to include any and all adaptations or modifications of the various embodiments. It should be understood that the above description is illustrative only and not limiting. Combinations of the above embodiments with other embodiments not specifically described herein will be apparent to those of skill in the art upon review of the above description. Thus, the scope of the various embodiments includes any other applications in which the above compositions, structures and methods are used.

[0077] Additionally, although the exemplary method 1600 has been described as a series of acts or events, the present invention is not limited to the illustrated ordering of such acts or events, unless specifically stated. For example, some acts may occur in a different order or contemporaneously with other acts or events, or in a different order or contemporaneously with other acts or events, apart from those illustrated and described herein in accordance with the present invention. Additionally, the illustrated acts or events are not all required to implement a methodology in accordance with the present disclosure.

[0078] Although the present subject matter has been described in terms of particular structural features and / or methodological acts, it is to be understood that the present subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms for implementing the claims.

Claims

1. 1. A stent comprising: a tubular scaffold having a first end opposite a second end, an internal lumen extending between the first end and the second end; a flared portion having an anchor region; a tubular scaffolding comprising: an intermediate section extending from the flared section, the intermediate section having a diameter greater than a diameter of the flared section; a liner extending at least partially along a surface of the tubular scaffolding, the liner extending longitudinally along the anchor region of the flaring portion and spaced radially inward from the anchor region of the flaring portion to promote tissue ingrowth at the anchor region of the flaring portion, the liner at a position along the intermediate portion positioned adjacent a target site to minimize leakage at the target site.

2. The stent of claim 1 , wherein the liner promotes tissue ingrowth at an intermediate anchor region of the intermediate section by spacing the intermediate anchor region from the intermediate section.

3. The stent of claim 2 , wherein the intermediate anchor region is disposed in an expanded portion of the intermediate section, the expanded portion having a third diameter greater than a diameter of the intermediate section.

4. The stent of claim 3 , wherein the liner is spaced from the expansion portion to promote tissue ingrowth at the expansion portion.

5. The stent of claim 1 , wherein the anchor regions are disposed along an angled portion of the flared portion, the angled portion extending away from a central longitudinal axis extending through the lumen.

6. The stent of claim 1 , wherein the intermediate section has a substantially constant diameter.

7. 10. The stent of claim 1, wherein the flaring section has a first scaffold configuration and the intermediate section has a second scaffold configuration, the first scaffold configuration and the second scaffold configuration being different.

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