Stent system for maintaining patency of a body lumen

Abstract

A system for maintaining patency of a body lumen may include a first endoprosthesis configured to transition from a straight configuration to a helical configuration forming a plurality of loops, and a second endoprosthesis configured to transition from a radially contracted configuration to a radially expanded configuration. The plurality of loops define a passageway having an inner diameter. At least a portion of the second endoprosthesis is disposed within the passageway in the radially expanded configuration.

Description

[Technical Field]

[0001] The present disclosure relates to medical devices and methods for making and / or using the medical devices. More particularly, the present disclosure relates to improved designs for stent systems for maintaining patency of a body lumen at a bifurcation. [Background technology]

[0002] One currently known treatment for alleviating biliary obstruction in the biliary system is the placement of a covered endoprosthesis or stent within a restricted body lumen (e.g., bile duct, pancreatic duct, etc.), such as that caused by stricture formation. For example, to relieve acute painful symptoms, it may be necessary to open a body lumen (e.g., bile duct, pancreatic duct, etc.) to allow the passage of bile and stone-related debris. In addition, the biliary system has several branches, bifurcations, and / or adjacent lumens. Placing a covered endoprosthesis or stent across the opening of a bifurcation and / or adjacent branch or lumen to treat a stenosed or obstructed body lumen may result in further obstruction of the currently open or unrestricted lumen, which may be undesirable. There remains a need to provide alternative endoprostheses or stents and alternative methods for manufacturing and using endoprostheses or stents. Summary of the Invention

[0003] In one example, a system for maintaining patency of a body lumen may include a first endoprosthesis having a lumen extending from a first end to a second end, the first endoprosthesis configured to transition from a straight configuration to a helical configuration forming a plurality of loops, and a second endoprosthesis configured to transition from a radially contracted configuration to a radially expanded configuration. The plurality of loops may define a passageway having an inner diameter. At least a portion of the second endoprosthesis may be disposed within the passageway in the radially expanded configuration.

[0004] Additionally or alternatively to any of the examples described herein, when the second endoprosthesis is positioned in the passage in a radially expanded configuration, at least a portion of the second endoprosthesis extends away from the passage.

[0005] Additionally or alternatively to any of the examples described herein, at least a portion of the first endoprosthesis extends away from the plurality of loops. Additionally or alternatively to any of the examples described herein, when the second endoprosthesis is positioned in a radially expanded configuration within the passage, the first end portion of the first endoprosthesis extends away from the second endoprosthesis in a direction transverse to the central longitudinal axis of the second endoprosthesis.

[0006] Additionally or alternatively to any of the examples described herein, when the second endoprosthesis is positioned in a radially expanded configuration within the passage, the second end portion of the first endoprosthesis extends away from the second endoprosthesis generally parallel to the central longitudinal axis of the second endoprosthesis.

[0007] Additionally or alternatively to any of the examples described herein, the first endoprosthesis is formed from a polymeric material. Additionally or alternatively to any of the examples described herein, a system for maintaining patency of a body lumen may include a first endoprosthesis having a lumen extending from a first end to a second end, the first endoprosthesis configured to transition from a straight configuration to a helical configuration forming a plurality of loops, and a second endoprosthesis configured to transition from a radially contracted configuration to a radially expanded configuration. The plurality of loops may define a passageway having an inner diameter. The second endoprosthesis may be configured to be disposed within the passageway. The second endoprosthesis may have an outer diameter in the radially expanded configuration. The outer diameter of the second endoprosthesis may be within 20% of the inner diameter of the passageway.

[0008] Additionally or alternatively to any of the examples described herein, the plurality of loops defines an outer diameter of between about 6 French and about 12 French. Additionally or alternatively to any of the examples described herein, the first endoprosthesis is self-biased toward a helical configuration.

[0009] Additionally or alternatively to any of the examples described herein, the second endoprosthesis is self-biased toward the radially expanded configuration. Additionally or alternatively to any of the examples described herein, the second endoprosthesis includes a polymeric covering extending along at least a portion of the length of the second endoprosthesis.

[0010] Additionally or alternatively to any of the examples described herein, the first endoprosthesis includes a corrugated section disposed between the first end and the plurality of loops.

[0011] Additionally or alternatively to any of the examples described herein, the first endoprosthesis includes one or more drainage holes extending through a sidewall of the first endoprosthesis. Additionally or alternatively to any of the examples described herein, the first endoprosthesis includes one or more anti-migration elements extending radially outward from the first endoprosthesis.

[0012] Additionally or alternatively to any of the examples described herein, a method of maintaining patency of a body lumen may include the steps of advancing a first endoprosthesis into a first body lumen in a straight configuration, deploying the first endoprosthesis into a spiral configuration forming a plurality of loops within the first body lumen, advancing a second endoprosthesis into the first body lumen in a radially contracted configuration, and transitioning the second endoprosthesis into a radially expanded configuration within the plurality of loops.

[0013] Additionally or alternatively to any of the examples described herein, the step of advancing the first endoprosthesis in a linear configuration into the first body lumen includes positioning a first end portion of the first endoprosthesis into a second body lumen adjacent to the first body lumen.

[0014] Additionally or alternatively to any of the examples described herein, when the second endoprosthesis is positioned in a radially expanded configuration within the multiple loops, the first end portion of the first endoprosthesis extends away from the second endoprosthesis in a direction transverse to the central longitudinal axis of the second endoprosthesis.

[0015] Additionally or alternatively to any of the examples described herein, the first endoprosthesis is self-biased toward a helical configuration when unconstrained. Additionally or alternatively to any of the examples described herein, the first endoprosthesis is constrained in a straight configuration by a guidewire when the first endoprosthesis is advanced into the first body lumen.

[0016] Additionally or alternatively to any of the examples described herein, the first endoprosthesis is constrained in a linear configuration by the delivery sheath when the first endoprosthesis is advanced into the first body lumen.

[0017] The above summary of some embodiments, aspects, and / or examples is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The following figures and detailed description more particularly exemplify these embodiments. [Brief explanation of the drawings]

[0018] The present disclosure can be more fully understood in consideration of the following detailed description in conjunction with the accompanying drawings. [Figure 1] 1A-1D illustrate selected aspects of a stent system and a method of using the stent system for maintaining patency of a body lumen. [Figure 2] 1A-1D illustrate selected aspects of a stent system and a method of using the stent system for maintaining patency of a body lumen. [Figure 3] 1A-1D illustrate selected aspects of a stent system and a method of using the stent system for maintaining patency of a body lumen. [Figure 4] 1A-1D illustrate selected aspects of a stent system and a method of using the stent system for maintaining patency of a body lumen. [Figure 5] 5A-5C show selected aspects of the stent of the stent system of FIGS. 1-4. [Figure 6] 6A-6C show selected aspects of alternative configurations of the stent of FIG. 5. [Figure 7] 1A-1D illustrate selected aspects of a stent system for maintaining patency of a body lumen. DETAILED DESCRIPTION OF THE INVENTION

[0019] While aspects of the present disclosure are susceptible to various modifications and alternative forms, specifics thereof are shown by way of example in the drawings and will be described in detail below. It should be understood, however, that the intention is not to limit aspects of the disclosure to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure.

[0020] The following description should be read with reference to the drawings, which are not necessarily to scale, in which like reference numerals indicate like elements throughout the several views. The detailed description and drawings are intended to illustrate, not limit, the present disclosure. Those skilled in the art will understand that the various elements described and / or illustrated can be arranged in various combinations and configurations without departing from the scope of the present disclosure. The detailed description and drawings illustrate example embodiments of the present disclosure.

[0021] For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification. All numerical values ​​herein are assumed to be modified by the term "about," whether explicitly stated or not. The term "about" in the context of numerical values ​​generally refers to a range of numbers that one of ordinary skill in the art would consider equivalent to the recited value (e.g., having the same function or result). In many cases, the term "about" may include numbers that are rounded to the nearest significant figure. Other uses of the term "about" (e.g., in contexts other than numerical values) can be assumed to have their ordinary and customary definition as understood from and consistent with the context of this specification, unless otherwise specified.

[0022] The recitation of numerical ranges by endpoints includes all numbers within that range, inclusive of the endpoints (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). Although certain preferred dimensions, ranges and / or values ​​for various components, features and / or specifications are disclosed, those skilled in the art, inspired by this disclosure, will understand that the desired dimensions, ranges and / or values ​​may deviate from those expressly disclosed.

[0023] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally employed in its sense including "and / or" unless the content clearly dictates otherwise. For ease of understanding, it should be noted that some features of the present disclosure may be described in the singular even though they may be multiple or repeat within the disclosed embodiments. Each instance of a feature may include and / or be encompassed by the singular disclosure unless expressly stated otherwise. For simplicity and clarity, not all elements of the present disclosure are necessarily shown in each figure or discussed in detail below. It will be understood, however, that the following discussion may equally apply to any and / or all of the components where more than one is present, unless expressly stated otherwise.

[0024] Relative terms such as "proximal," "distal," "advance," "retract," and variations thereof may generally be considered with respect to the positioning, orientation, and / or movement of various elements relative to a user / operator / pilot of a device, with "proximal" and "retract" indicating or referring to being closer to or toward the user and "distal" and "advance" indicating or referring to being farther from or away from the user. In some cases, the terms "proximal" and "distal" may be assigned arbitrarily to facilitate understanding of the present disclosure, and such instances will be readily apparent to those skilled in the art. Other relative terms, such as "upstream," "downstream," "inflow," and "outflow," refer to the direction of fluid flow within a body lumen, a lumen such as a blood vessel, or within a device. Still other relative terms, such as "axial," "circumferential," "longitudinal," "lateral," "radial," and / or variations thereof, generally refer to directions and / or orientations relative to a central longitudinal axis of the disclosed structures or devices.

[0025] The term "range" can be understood to mean the maximum measurement of the stated or specified dimension unless the range or dimension is preceded by "minimum," which can be understood to mean the minimum measurement of the stated or specified dimension, or the maximum measurement of the stated or specified dimension unless the range or dimension is identified as a "minimum." For example, an "outer range" can be understood to mean the outer dimension, a "radial range" can be understood to mean the radial dimension, a "longitudinal range" can be understood to mean the longitudinal dimension, etc. A "range" may vary from case to case (e.g., axial, longitudinal, lateral, radial, circumferential, etc.) and will be apparent to one of ordinary skill in the art from the context of a particular use. Generally, a "range" can be considered the maximum possible dimension measured according to the intended use, and a "minimum range" can be considered the minimum possible dimension measured according to the intended use. In some cases, a "range" may generally be measured diagonally in a plane and / or cross-section, but may also be measured differently (including, but not limited to, diagonally, radially, circumferentially (e.g., along an arc), etc.) as is apparent from the particular context.

[0026] The terms "monolithic" and "integral" shall generally refer to an element or elements made from or consisting of a single structure or basic unit / element. Monolithic and / or integral elements shall exclude structures and / or features made by assembling or otherwise joining together multiple separate structures or elements.

[0027] It should be noted that references in the specification to "one embodiment," "some embodiments," "other embodiments," etc., indicate that the described embodiment may include a particular feature, structure, or characteristic, but not all embodiments necessarily include that particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or measurement is described in connection with one embodiment, it is within the knowledge of one skilled in the art to implement that particular feature, structure, or characteristic in connection with other embodiments, whether or not explicitly stated, unless expressly stated otherwise. That is, various individual elements described below, even if not explicitly shown in specific combinations, are contemplated as being combinable or configurable with one another to form other or additional embodiments or to complement and / or expand the described embodiments, as understood by one skilled in the art.

[0028] For purposes of clarity, certain distinguishing numerical nomenclature (e.g., first, second, third, fourth, etc.) may be used throughout the specification and claims to name and / or identify various described and / or claimed features. It should be understood that this numerical nomenclature is not intended to be limiting and is merely exemplary. In some embodiments, for brevity and clarity, variations may be made and deviate from previously used numerical nomenclature. That is, a feature identified as a "first" element may later be referred to as a "second," "third," etc., or may be omitted entirely, and / or a different feature may be referred to as the "first" element. The meaning and / or designation in each instance will be apparent to those of ordinary skill in the art.

[0029] The figures show selected components and / or arrangements of the system. It should be noted that in any given figure, some features of the system may not be shown or may be shown in schematic form for ease of illustration. Additional details regarding some of the system's components may be shown in greater detail in other figures. For ease of understanding, it should be noted that some features of the present disclosure may be described in the singular even though they may be multiple or repeat within the disclosed embodiments. Each instance of a feature may include and / or be encompassed by the singular disclosure unless expressly stated otherwise. Accordingly, it will be understood that the following discussion may apply equally to any and / or all of the components present in multiples within a system unless expressly stated otherwise. Furthermore, for clarity, each figure may not show every instance of some elements or features.

[0030] The following disclosure describes aspects of a stent system. For clarity and / or brevity, the term "stent" will be used herein, and the term "stent" shall include and / or encompass other similar terminology, such as, but not limited to, "endoprosthesis." The present disclosure also refers to the treatment of body lumens, particularly body lumens having bifurcations and / or adjacent bifurcations. For brevity, the term "body lumen" includes, but is not limited to, specific body lumens such as the bile duct, hepatic duct, cystic duct, common bile duct, pancreatic duct, and bronchi. The system is also contemplated for use in other body lumens.

[0031] FIG. 1 illustrates selected features of a first body lumen 10 and a second body lumen 20 (e.g., a branch lumen) adjacent to the first body lumen 10. In some examples, the first body lumen 10 and the second body lumen 20 may meet at a bifurcation 12. In other words, the second body lumen 20 may branch or diverge from the first body lumen 10 at the bifurcation 12, or the first body lumen 10 may branch or diverge from the second body lumen 20 at the bifurcation 12. Thus, the first body lumen 10 and the second body lumen 20 may be connected or joined at the bifurcation 12. As shown in FIG. 1, the first body lumen 10 may include a stricture 14 (e.g., an occlusion) disposed along the inner surface of the wall of the first body lumen 10. As shown in FIG. 1, the stricture 14 may be located upstream of the bifurcation 12, for example. However, in other instances, the stenosis 14 may be located downstream of the bifurcation 12. When a covered endoprosthesis or stent is placed within the stenosis 14 formed in the first body lumen 10, the second body lumen 20 may be partially or completely occluded because the covered endoprosthesis or stent spans the bifurcation 12. Thus, fluid flowing from the second body lumen 20 may be prevented from flowing downstream into the first body lumen 10. When treating the first body lumen 10, it is desirable to maintain the patency of the second body lumen 20 to allow fluid to flow from the second body lumen 20 into the first body lumen 10.

[0032] A method of maintaining patency of a body lumen using the systems disclosed herein may include advancing a guidewire 90 into a first body lumen 10. In some embodiments, the method may further include advancing the guidewire 90 from the first body lumen 10 into a second body lumen 20 upstream of a bifurcation 12. The method may include advancing a first endoprosthesis 100 in a straight configuration over the guidewire 90 into the first body lumen 10, as shown in FIG. 1 . It should be understood that the term “endoprosthesis” as used herein may be used interchangeably with the term “stent.” In some embodiments, the first endoprosthesis 100 may be constrained in a straight configuration by the guidewire 90 as the first endoprosthesis 100 is advanced through the first body lumen 10 into the second body lumen 20. In some alternative embodiments, the first endoprosthesis 100 may be constrained in a straight configuration by a delivery sheath (not shown) that surrounds the first endoprosthesis 100 as it is advanced through the first body lumen 10 and into the second body lumen 20. Other configurations, including combinations thereof, are also contemplated.

[0033] In some embodiments, as shown in FIG. 1 , advancing a first endoprosthesis 100 in a straight line through a first body lumen 10 into a second body lumen 20 downstream of a bifurcation 14 may include positioning a first end portion 110 of the first endoprosthesis 100 within the second body lumen 20, such as upstream of the bifurcation 12, and leaving a second end portion 112 of the first endoprosthesis 100 within the first body lumen 10, such as downstream of the bifurcation 12.

[0034] The method may include deploying the first endoprosthesis 100 in a helical configuration with a first end portion 110 of the first endoprosthesis 100 in the second body lumen 20, such as upstream of the bifurcation 12, and a second end portion 112 of the first endoprosthesis 100 in the first body lumen 10, such as downstream of the bifurcation 12. Thus, a middle portion of the first endoprosthesis 100 may be located at the bifurcation 12 when deployed in the helical configuration. When deployed in the helical configuration, the middle portion of the first endoprosthesis 100 may form a plurality of helical loops 130, as shown in FIG. As shown in FIG. 2 , the first endoprosthesis 100 may be deployed at a bifurcation with the plurality of helical loops 130 disposed within a first body lumen 10 proximal (e.g., downstream) of the bifurcation 12 and the first end region 110 of the endoprosthesis 100 disposed within a second body lumen 10 distal (e.g., upstream) of the bifurcation 12. In the deployed helical configuration, the radially outward flaring of the helical loops 130 may contact and / or press radially outward against the inner surface of the first body lumen 10. The first endoprosthesis 100 may be configured to automatically transition from a straight configuration (in which the helical loops 130 are straightened or elongated) when constrained by a guidewire 90 (or an outer sheath, if present) to a helical configuration (e.g., FIGS. 2 and 5 ) when unconstrained. In at least some embodiments, the first endoprosthesis 100 may be self-biased toward the helical configuration when unconstrained.

[0035] 5, which shows selected aspects of a first endoprosthesis 100 in more detail, the first endoprosthesis 100 may have a lumen 102 extending from a first end 104 to a second end 106. In some embodiments, the first end 104 may be the distal end of the first endoprosthesis 100 and the second end 106 may be the proximal end of the first endoprosthesis 100 during use, although this is not required.

[0036] In some embodiments, at least a portion of the first endoprosthesis 100 can extend away from the plurality of helical loops 130 in the helical configuration. In some embodiments, the first end portion 110 can extend away from the plurality of helical loops 130 in the helical configuration. In some embodiments, the first end portion 110 can extend from the plurality of helical loops 130 to the first end 104 of the first endoprosthesis 100. In some embodiments, the second end portion 112 can extend away from the plurality of helical loops 130 in the helical configuration. In some embodiments, the second end portion 112 can extend from the plurality of helical loops 130 to the second end 106 of the first endoprosthesis 100.

[0037] In some embodiments, the first endoprosthesis 100 may include one or more anti-migration elements 120. In some embodiments, the one or more anti-migration elements 120 may be integrally and / or monolithically formed with the first endoprosthesis 100. In some embodiments, the one or more anti-migration elements 120 may be configured to be disposed substantially flush with an outer surface of the first endoprosthesis 100 in a straight configuration (e.g., when the first endoprosthesis 100 is constrained in a straight configuration) and / or during advancement and / or delivery into the first body lumen 10, as shown in FIG.

[0038] In some embodiments, one or more anti-migration elements 120 may be configured to extend radially outward from first endoprosthesis 100 in a helical configuration and / or in an unconstrained state, as shown in FIGS. 2 and 5 . In some embodiments, one or more anti-migration elements 120 may be disposed within first end portion 110 and / or second end portion 112. In some embodiments, one(s) of one or more anti-migration elements 120 may be disposed within first end portion 110 and one(s) of one or more anti-migration elements 120 may be disposed within second end portion 112. In some embodiments, one or more anti-migration elements 120 may be disposed only within first end portion 110. In some embodiments, one or more anti-migration elements 120 may be disposed only within second end portion 112. In some embodiments, one or more anti-migration elements 120 can be self-biased to extend radially outward from the first endoprosthesis 100 in a helical configuration. In some embodiments, the first endoprosthesis 100 can include a mechanism configured to bias the one or more anti-migration elements 120 to extend radially outward from the first endoprosthesis 100 in a helical configuration. Other configurations are also contemplated. The one or more anti-migration elements 120 can be configured to engage with an inner surface of a body lumen in which the first endoprosthesis 100 is disposed (e.g., the one or more anti-migration elements 120 can be configured to engage with an inner surface of the first body lumen 10 and / or the second body lumen 20). In some examples, the anti-migration elements 120 can be barbs extending from a tubular wall of the first endoprosthesis. In other embodiments, anti-migration element 120 can be a pigtail or a helical anchor located on first end portion 110 and / or second end portion 112 .

[0039] Referring again to FIG. 5 , in some embodiments, the first endoprosthesis 100 may include one or more drainage ports 140 extending through a sidewall of the first endoprosthesis 100. The one or more drainage ports 140 may be in fluid communication with the lumen 102. The one or more drainage ports 140 may be disposed along the first end portion 110, the second end portion 112, and / or the plurality of helical loops 130. While shown in FIG. 5 as being disposed along the first end portion 110 and the second end portion 112, in some embodiments, the one or more drainage ports 140 may be disposed only along the first end portion 110, only along the second end portion 112, and / or only along the plurality of helical loops 130. In some embodiments, the one or more drainage ports 140 may be disposed along substantially the entire length of the first endoprosthesis 100, or along any portion thereof.

[0040] In some embodiments, the plurality of helical loops 130 form a passageway 150 having an inner diameter 132. In some embodiments, the plurality of helical loops 130 may extend circumferentially around the passageway 150 and / or a longitudinal axis of the passageway 150. In at least some embodiments, the plurality of helical loops 130 may extend helically around the passageway 150 and / or a longitudinal axis of the passageway 150 in a helical configuration.

[0041] The passageway 150 may be outlined by the inner extent of the plurality of helical loops 130 as formed by the outer surface of the tubular wall of the first endoprosthesis 100. The plurality of helical loops 130 may define an outer diameter 134 and / or an outermost extent formed by the outer surface of the tubular wall of the first endoprosthesis 100. In some embodiments, the outer diameter 134 and / or outermost extent of the plurality of helical loops 130 may be about 6 French (Fr) to about 15 Fr (e.g., about 2 millimeters to about 5 millimeters). In some embodiments, the outer diameter 134 and / or outermost extent of the plurality of helical loops 130 may be about 6 Fr to about 12 Fr (e.g., about 2 millimeters to about 4 millimeters). In some embodiments, the outer diameter 134 and / or outermost extent of the multiple spiral loops 130 can be about 6 Fr (e.g., about 2 millimeters), about 7 Fr (e.g., about 2.33 millimeters), about 8 Fr (e.g., about 2.67 millimeters), about 9 Fr (e.g., about 3 millimeters), about 10 Fr (e.g., about 3.33 millimeters), about 11 Fr (e.g., about 3.67 millimeters), about 12 Fr (e.g., about 4 millimeters), about 13 Fr (e.g., about 4.33 millimeters), about 14 Fr (e.g., about 4.67 millimeters), about 15 Fr (e.g., about 5 millimeters), etc.

[0042] In some embodiments, the elongate tube of the first endoprosthesis 100 can have a first overall length in a straight form of about 40 millimeters to about 300 millimeters, about 50 millimeters to about 275 millimeters, about 60 millimeters to about 250 millimeters, about 80 millimeters to about 225 millimeters, about 100 millimeters to about 200 millimeters, about 110 millimeters to about 175 millimeters, or another suitable range.

[0043] In at least some embodiments, the first endoprosthesis 100 may be formed from a polymeric material. For example, the first endoprosthesis 100 may be formed from a polymeric tubular member extending from the first end 104 to the second end 106 of the first endoprosthesis 100. The polymeric tubular member may maintain a constant diameter as the first endoprosthesis 100 transitions between a straight and a helical configuration. In other words, the polymeric tubular member may be a polymeric tube that does not significantly expand radially as the first endoprosthesis 100 transitions from a straight to a helical configuration, thus maintaining a constant diameter of the polymeric tubular member. The polymeric tubular member may be formed (e.g., heat-set) to include helical loops 130 along an intermediate region of the polymeric tubular member when unconstrained. When the polymeric tubular member is stretched, and thus straightened, the helical loops 130 may disappear, providing a straight configuration when constrained for delivery to the bifurcation 12. Some suitable, non-limiting examples of materials for the first endoprosthesis 100 are described herein.

[0044] 3 , once the first endoprosthesis 100 has been delivered past the bifurcation 12 and expanded into a helical configuration, the method may include advancing a guidewire 190 into the first body lumen 10. The method may further include, after deploying the first endoprosthesis in a helical configuration, advancing the guidewire 190 into and / or through the plurality of helical loops 130 and / or through the passages 150 of the first endoprosthesis 100. The method may further include advancing a second endoprosthesis 200 over the guidewire 190 into the first body lumen 10 in a radially contracted configuration. Thus, the second endoprosthesis 200 can be positioned in a radially constrained or contracted configuration within the spiral loop 130 such that the spiral loop 130 surrounds the radially constrained or contracted second endoprosthesis 200, with the second endoprosthesis 200 extending from a portion of the first body lumen 10 proximal (e.g., downstream) of the bifurcation 12 to a portion of the first body lumen 10 distal (e.g., upstream) of the bifurcation 12. The second endoprosthesis 200 may be positioned so that the distal end region of the second endoprosthesis 200 extends beyond the stenosis 14 (in the first body lumen 10 upstream of the bifurcation 12) in a radially constrained or contracted form, and the proximal end region of the second endoprosthesis 200 passes through the spiral loop 130 of the first endoprosthesis 100 in the first body lumen 10 downstream of the bifurcation 12.

[0045] The second endoprosthesis 200 can be configured to transition from a radially contracted configuration to a radially expanded configuration (e.g., FIG. 4 ). In at least some embodiments, the second endoprosthesis 200 can be self-biased toward the radially expanded configuration. In some embodiments, the second endoprosthesis 200 can be formed from a superelastic and / or shape-memory material, such as Nitinol. In some embodiments, the second endoprosthesis 200 can be constrained in the radially contracted configuration by the properties of the shape-memory material when the second endoprosthesis 200 is advanced into the first body lumen 10. In some embodiments, the second endoprosthesis 200 can be constrained in the radially contracted configuration by a delivery sheath 210 surrounding the second endoprosthesis 200 when the second endoprosthesis 200 is advanced into the first body lumen 10, as shown in FIG. 3 . Other configurations, including combinations thereof, are also contemplated.

[0046] The second endoprosthesis 200 may include an expandable framework extending axially from a first end (which in some instances may be considered the proximal end) to a second end (which in some instances may be considered the distal end) along a central longitudinal axis of the second endoprosthesis 200 and / or the expandable framework. In at least some embodiments, the second endoprosthesis 200 and / or the expandable framework may be self-expandable when unconstrained. In some embodiments, the second endoprosthesis 200 and / or the expandable framework may be mechanically expandable. For example, the second endoprosthesis 200 and / or the expandable framework may be expandable using an inflatable balloon, using an actuation member, or using other suitable means.

[0047] The expandable framework can include and / or be formed of multiple cells. In some embodiments, the expandable framework can include and / or be formed from one or more filaments woven around a central longitudinal axis of the second endoprosthesis 200 and / or the expandable framework. In at least some embodiments, the one or more filaments can form and / or define multiple cells. In some embodiments, the expandable framework can be braided, knitted, or woven from one or more filaments. In some embodiments, the one or more filaments can be wires, threads, strands, etc. In some embodiments, adjacent filaments of the one or more filaments can define cells (i.e., openings or gaps) that penetrate the wall of the expandable framework. Alternatively, in some embodiments, the expandable framework may be a monolithic structure formed from a cylindrical tubular member, such as a single cylindrical laser-cut nickel-titanium (e.g., nitinol) tubular member, with the remaining (e.g., unremoved) portions of the tubular member forming the stent struts and / or framework with cells (i.e., openings or gaps) defined therebetween.

[0048] The second endoprosthesis 200 and / or the expandable framework may be substantially tubular and / or may include and / or define a lumen extending axially through the second endoprosthesis 200 and / or the expandable framework from a first end to a second end along a central longitudinal axis of the second endoprosthesis 200 and / or the expandable framework. In some embodiments, the second endoprosthesis 200 and / or the expandable framework may have an axial length of about 20 millimeters to about 200 millimeters, about 30 millimeters to about 175 millimeters, about 40 millimeters to about 150 millimeters, about 50 millimeters to about 125 millimeters, about 75 millimeters to about 100 millimeters, or another suitable range. In some embodiments, the second endoprosthesis 200 and / or the expandable framework may have an outer diameter of about 0.5 millimeters to about 5 millimeters, about 0.75 millimeters to about 4.5 millimeters, about 1 millimeter to about 4 millimeters, about 1.5 millimeters to about 3.5 millimeters, or another suitable range. In some embodiments, the second endoprosthesis 200 and / or the expandable framework can have an outer diameter of about 4 millimeters to about 28 millimeters, about 4 millimeters to about 14 millimeters, about 14 millimeters to about 28 millimeters, and / or any other subset thereof. Other configurations are also contemplated. Some suitable, but non-limiting, materials for the second endoprosthesis 200, the expandable framework, and / or their components or elements, such as metallic and / or polymeric materials, are described below.

[0049] In some embodiments, the first overall length of the elongate tube of the first endoprosthesis 100 in the straight configuration may be related to the axial length of the second endoprosthesis 200. As shown and / or described herein, at least a portion of the first end portion 110 and the second end portion 112 of the first endoprosthesis 100 may extend proximally and distally, respectively, of the second endoprosthesis 200. In some embodiments, the first overall length of the first endoprosthesis 100 in the straight configuration may be approximated as the axial length of the second endoprosthesis 200 + (the circumference of the second endoprosthesis 200 × the number of helical loops in the plurality of helical loops 130) + the length of the first end portion 110 and the second end portion 112 of the first endoprosthesis 100 extending away from each end of the second endoprosthesis 200.

[0050] The approximate overall length of the elongate tube of the first endoprosthesis 100 in the helical configuration is less than the first overall length. In one non-limiting example, the axial length of the second endoprosthesis 200 may be approximately 100 millimeters, and the outer diameter of the second endoprosthesis 200 may be approximately 10 millimeters. One example of a first endoprosthesis 100 associated with and / or used with the example second endoprosthesis 200 described above has a first overall length in the straight configuration of approximately 300 millimeters and an approximate overall length in the helical configuration of approximately 120 millimeters. Other configurations and / or examples are contemplated.

[0051] In some embodiments, the expandable framework may include a first flared portion proximate a first end of the expandable framework. The first flared portion may extend from the first end toward a second end. In some embodiments, the expandable framework may include a second flared portion proximate a second end of the expandable framework. The second flared portion may extend from the second end toward the first end. In at least some embodiments, the second flared portion may be longitudinally and / or axially spaced from the first flared portion by the body portion. In some embodiments, the first flared portion and / or the second flared portion may be configured to exert a radially outward force on the wall of the first body lumen 10 to prevent migration of the second endoprosthesis 200 within the first body lumen 10.

[0052] In some embodiments, the delivery sheath 210 may be an elongate catheter or other tubular shaft suitable for and / or known in the art for delivering an endoprosthesis. The second endoprosthesis 200 may be disposed within the lumen of the delivery sheath 210 in a radially constrained or contracted configuration. In the radially constrained or contracted configuration, the expandable framework may be substantially straight and / or fully extended. The second endoprosthesis 200 may be deployed from the delivery sheath 210 using one or more known techniques, such as by retracting the delivery sheath 210 proximally from the second endoprosthesis 200 to eject the second endoprosthesis 200 from the delivery sheath 210. Other techniques commonly known, but not described for the sake of brevity, may be used to deploy the second endoprosthesis 200 from the delivery sheath 210.

[0053] The method may include transitioning the second endoprosthesis 200 to a radially expanded configuration within the plurality of loops 130 and / or passages 150, as shown in Figure 4. In some embodiments, transitioning the second endoprosthesis 200 to a radially expanded configuration may include withdrawing and / or retracting the delivery sheath 210 relative to the second endoprosthesis 200 to expose the second endoprosthesis 200 within the first body lumen 10 and / or within the plurality of loops 130 and / or passages 150, thereby allowing the second endoprosthesis 200 to radially expand.

[0054] In at least some embodiments, the second endoprosthesis 200 and / or the expandable framework can be deployed within a body lumen extending through a stricture to maintain and / or re-establish patency of the body lumen. In some embodiments, the second endoprosthesis 200 and / or the expandable framework can be configured to expand at least a portion of the body lumen in a radially expanded configuration. For example, the second endoprosthesis 200 and / or the expandable framework can be configured to exert a radially outward force against the wall of the body lumen and / or against a stricture formed within the body lumen.

[0055] In some embodiments, at least a portion of the second endoprosthesis 200 can be disposed within the plurality of loops 130 and / or passages 150 in the radially expanded configuration. In some embodiments, at least a portion of the second endoprosthesis 200 can extend away from the plurality of loops 130 and / or passages 150 when the second endoprosthesis 200 is disposed within the plurality of loops 130 and / or passages 150 in the radially expanded configuration.

[0056] In some embodiments, the second endoprosthesis 200 and / or the expandable framework can be configured to engage the plurality of loops 130 and / or passages 150 in the radially expanded configuration. In the radially expanded configuration, the second endoprosthesis 200 and / or the expandable framework can be configured to apply a radially outward force to the first endoprosthesis 100 and / or plurality of loops 130 in the helical configuration, thereby engaging and / or urging the first endoprosthesis 100 and / or plurality of loops 130 against the wall of the first body lumen 10. In some examples, a portion of the second endoprosthesis 200 extending between adjacent loops 130 can extend radially outward and contact the wall of the first body lumen 10.

[0057] In some embodiments, the second endoprosthesis 200 can be configured to expand at least a portion of the first body lumen 10 in the radially expanded configuration. For example, the second endoprosthesis 200 can be configured to exert a radially outward force on the wall of the first body lumen 10 and / or the stricture 14 in the radially expanded configuration. In some embodiments, the second endoprosthesis 200 and / or the expandable framework can be configured to extend beyond an opening to an adjacent body lumen (e.g., the second body lumen 20). In other words, the second endoprosthesis 200 can be configured to extend beyond the bifurcation 12 such that a first end region of the second endoprosthesis 200 is positioned within the first body lumen 10 upstream of the bifurcation 12 (e.g., beyond the stricture 14) and a second end region of the second endoprosthesis 200 is positioned within the first body lumen 10 downstream of the bifurcation 12.

[0058] In some embodiments, when the second endoprosthesis 200 is disposed in a radially expanded configuration within the plurality of loops 130 and / or passages 150, the first end portion 110 of the first endoprosthesis 100 can extend away from the second endoprosthesis 200 in a direction transverse to a central longitudinal axis of the second endoprosthesis 200. In some embodiments, when the second endoprosthesis 200 is disposed in a radially expanded configuration within the plurality of loops 130 and / or passages 150 (the second endoprosthesis 200 can be disposed in the first body lumen 20 downstream of the bifurcation 12), the first end portion 110 of the first endoprosthesis 100 can extend away from the second endoprosthesis 200 into the second body lumen 20.

[0059] In some embodiments, when the second endoprosthesis 200 is disposed in a radially expanded configuration within the plurality of loops 130 and / or passages 150 (which may be disposed in the first body lumen 20 downstream of the bifurcation 12), the second end portion 112 of the first endoprosthesis 100 may extend away from the second endoprosthesis 200 generally parallel to a central longitudinal axis of the second endoprosthesis 200. In some embodiments, when the second endoprosthesis 200 is disposed in a radially expanded configuration within the plurality of loops 130 and / or passages 150, the second end portion 112 of the first endoprosthesis 100 may extend away from the second endoprosthesis 200 within the first body lumen 10.

[0060] In some embodiments, the second endoprosthesis 200 can have an outer diameter and / or outward extent in the radially expanded configuration. In some embodiments, the outer diameter and / or outward extent of the second endoprosthesis 200 can be within about 20% of the inner diameter 132 of the passageway 150. In some embodiments, the outer diameter and / or outward extent of the second endoprosthesis 200 can be within about 15% of the inner diameter 132 of the passageway 150. In some embodiments, the outer diameter and / or outward extent of the second endoprosthesis 200 can be within about 10% of the inner diameter 132 of the passageway 150. In some embodiments, the outer diameter and / or outward extent of the second endoprosthesis 200 can be within about 5% of the inner diameter 132 of the passageway 150. In some embodiments, the outer diameter and / or outward extent of the second endoprosthesis 200 can be substantially the same as the inner diameter 132 of the passageway 150.

[0061] In some embodiments, the portion of the second endoprosthesis 200 extending between adjacent loops of the plurality of loops 130 (when radially expanded within the plurality of loops 130 of the first endoprosthesis 100) may have a second outer diameter and / or second outward extension that is greater than the outer diameter and / or outward extension of the second endoprosthesis 200 disposed within the passage 150 and / or the plurality of loops 130, such that the portion of the second endoprosthesis 200 extends radially outward between adjacent loops 130.

[0062] In some embodiments, the second endoprosthesis 200 and / or the expandable framework may include a polymeric covering 220 disposed on, covering, and / or extending along at least a portion of its length. In some embodiments, the polymeric covering 220 may be disposed on and / or along the first flared portion, the second flared portion, and / or the body portion extending between the first and second flared portions. In some embodiments, the polymeric covering 220 may be disposed on and / or along the outer surface of the expandable framework. In some embodiments, at least a portion of the expandable framework may be embedded in the polymeric covering 220. In some embodiments, the polymeric covering 220 may be fixedly or releasably secured, adhered, or otherwise attached to the expandable framework. In some embodiments, the polymeric covering 220 may be impermeable to fluids, debris, medical devices, etc. Some suitable, but non-limiting, materials for the polymeric covering 220 are described below.

[0063] In some embodiments, the polymeric covering 220 can extend along the entire length and / or circumference of the second endoprosthesis 200 and / or expandable framework. In some embodiments, the polymeric covering 220 can extend along a portion of the length of the second endoprosthesis 200 and / or expandable framework. In some embodiments, the polymeric covering 220 can be discontinuous. In some embodiments, the polymeric covering 220 can extend discontinuously between a first end (e.g., a proximal end) of the second endoprosthesis 200 and / or expandable framework and a second end (e.g., a distal end) of the second endoprosthesis 200 and / or expandable framework in the radially expanded configuration. In some embodiments, the polymeric covering 220 can extend continuously from a first end (e.g., a proximal end) of the second endoprosthesis 200 and / or expandable framework to a second end (e.g., a distal end) of the second endoprosthesis 200 and / or expandable framework in the radially expanded configuration. Other configurations are also contemplated.

[0064] After the second endoprosthesis 200 is deployed within the plurality of loops 130 and / or passageways 150, the second endoprosthesis 200 and the polymer cover 220 (if present) may cooperate with the first endoprosthesis 100 to form a spiral fluid pathway around (e.g., on its exterior) the second endoprosthesis 200 from the second body lumen 20 to the lower portion of the first body lumen 10. In at least some embodiments, the first endoprosthesis 100 may form a gap 30 between the exterior (e.g., outer surface) of the second endoprosthesis 200 and the wall of the first body lumen 10, and the gap 30 may form a spiral fluid pathway around the exterior (e.g., outer surface) of the second endoprosthesis 200.

[0065] In some embodiments, the first endoprosthesis 100 can be configured to provide drainage from the second body lumen 20 into the first body lumen 10 internally and / or through the lumen 102 of the first endoprosthesis 100. In some embodiments, the first endoprosthesis 100, in cooperation with the second endoprosthesis 200 and the polymer cover 220 (if present), can provide drainage from the second body lumen 20 to the first body lumen 10 externally along and / or using a spiral fluid path around the exterior of the second endoprosthesis 200. In some embodiments, the first endoprosthesis 100 may be configured to provide a drainage path from the second body lumen 20 to the first body lumen 10 both internally (e.g., through the lumen 102 of the first endoprosthesis 100) and externally (e.g., along the exterior of the first endoprosthesis 100 forming a gap 30 along the exterior of the second endoprosthesis 200).

[0066] 6 illustrates selected aspects of alternative configurations of the first endoprosthesis 100. In some embodiments, the first endoprosthesis 100 may include a flexible region, such as a corrugated portion 160, disposed between the first end 104 and the plurality of loops 130. The flexible region (e.g., corrugated portion 160) may be more flexible than the remainder of the length of the first endoprosthesis 100, including portions of the tubular member of the first endoprosthesis 100 on either side of the flexible region. In some embodiments, the first end portion 110 may include the corrugated portion 160. In some embodiments, the corrugated portion 160 may separate the first end portion 110 into a first portion 162 and a second portion 164, with the flexible region (e.g., corrugated portion 160) being between the first portion 162 and the second portion 164. In some embodiments, the first portion 162 may be positioned proximal to the flexible or corrugated portion 160 and / or between the flexible or corrugated portion 160 and the plurality of loops 130, and the second portion 164 may be positioned distal to the flexible or corrugated portion 160 and / or between the flexible or corrugated portion 160 and the first end 104.

[0067] In some embodiments, the corrugated portion 160 may resemble an accordion and / or a bellows. The corrugated portion 160 may add an additional aspect of flexibility and / or bendability to the first end portion 110 of the first endoprosthesis 100. In some embodiments, the first endoprosthesis 100 having the corrugated portion 160 may be configured to easily conform to the irregular nature of tortuous anatomy. In some embodiments, the corrugated portion 160 may be configured to bend and / or deflect the second portion 164 relative to the first portion 162. In other words, the central longitudinal axis of the second portion 164 may extend at a non-parallel angle (e.g., an acute angle, a right angle, or an obtuse angle) relative to the central longitudinal axis of the first portion 162. In some embodiments, the second portion 164 may bend and / or deflect in the same plane as the first portion 162. In some embodiments, second portion 164 may bend and / or deflect at an angle and / or non-coplanarly relative to first portion 162. Other configurations are also contemplated.

[0068] In some embodiments, the undulating portion 160 can be manipulated by the guidewire 90 during delivery of the first endoprosthesis 100. In some embodiments, the undulating portion 160 can be steerable using one or more mechanisms incorporated into the first endoprosthesis 100. For example, one or more steering wires can be disposed within the first endoprosthesis 100 and / or can extend along the wall of the first endoprosthesis 100. Other configurations are also contemplated.

[0069] 7 illustrates selected aspects of alternative uses and / or configurations of the systems and / or methods for maintaining patency of a body lumen disclosed herein. In some embodiments, the method may include advancing a guidewire into a first body lumen 10 such that the guidewire extends upstream of a bifurcation 12. The method may include advancing a first endoprosthesis 100 in a straight configuration over the guidewire into the first body lumen 10 to a position where the first endoprosthesis 100 spans the bifurcation 12, with a distal end region of the first endoprosthesis 100 positioned in the first body lumen 10 upstream of the bifurcation 12 and a proximal end region of the first endoprosthesis 100 positioned in the first body lumen 10 downstream of the bifurcation 12. In some embodiments, the first endoprosthesis 100 may be constrained in a straight configuration by a guidewire as the first endoprosthesis 100 is advanced through the first body lumen 10 and past the bifurcation 12. In some alternative embodiments, the first endoprosthesis 100 may be constrained in a straight configuration by a delivery sheath that surrounds the first endoprosthesis 100 as the first endoprosthesis 100 is advanced through the first body lumen 10 and past the bifurcation 12. Other configurations, including combinations thereof, are also contemplated. In some embodiments, advancing the first endoprosthesis 100 in a straight line into the first body lumen 10 may include positioning a first end portion 110 of the first endoprosthesis 100 in the first body lumen 10 upstream of the bifurcation 12 and positioning a second end portion 112 of the first endoprosthesis 100 in the first body lumen 10 downstream of the bifurcation 12 so that an intermediate region of the first endoprosthesis 100 spans the bifurcation 12.

[0070] The method may include deploying the first endoprosthesis 100 in a helical configuration that forms multiple loops 130 within the first body lumen 10, with a first end portion 110 of the first endoprosthesis 100 in the first body lumen 10 on a first side of the bifurcation 12, such as upstream of the bifurcation 12, and a second end portion 112 of the first endoprosthesis 100 in the first body lumen 10 on a second side of the bifurcation 12, such as downstream of the bifurcation 12, as shown in FIG. 7 . Thus, a middle portion of the first endoprosthesis 100 may be located at the bifurcation 12 when deployed in the helical configuration. When deployed in the helical configuration, the middle portion of the first endoprosthesis 100 may form multiple helical loops 130. The first endoprosthesis 100 can be configured to automatically transition from a straight configuration (in which the helical loops 130 are straightened or elongated) when constrained by the guidewire 90 (or the outer sheath, if present) to a helical configuration when unconstrained. In at least some embodiments, the first endoprosthesis 100 can be self-biased toward the helical configuration when unconstrained.

[0071] In some embodiments, at least a portion of the first endoprosthesis 100 can extend away from the plurality of loops 130 in a spiral configuration. In some embodiments, the first end portion 110 can extend away from the plurality of loops 130 in a spiral configuration. In some embodiments, the first end portion 110 can extend from the plurality of loops 130 to the first end 104 of the first endoprosthesis 100. In some embodiments, the second end portion 112 can extend away from the plurality of loops 130 in a spiral configuration. In some embodiments, the second end portion 112 can extend from the plurality of loops 130 to the second end 106 of the first endoprosthesis 100.

[0072] Once the first endoprosthesis 100 has been delivered past the bifurcation 12 and expanded into a helical configuration, the method may include advancing a second guidewire into the first body lumen 10. The method may further include, after deploying the first endoprosthesis in a helical configuration, advancing a second guidewire into and / or through the plurality of helical loops 130 and / or through the passages 150 of the first endoprosthesis 100. The method may further include advancing a second endoprosthesis 200 into the first body lumen 10 over the second guidewire in a radially contracted configuration. Thus, the second endoprosthesis 200 can be positioned within the helical loop 130 in a radially constrained or contracted configuration such that the helical loop 130 surrounds the radially constrained or contracted second endoprosthesis 200, with the second endoprosthesis 200 extending from a portion of the first body lumen 10 proximal (e.g., downstream) of the bifurcation 12 to a portion of the first body lumen 10 distal (e.g., upstream) of the bifurcation 12. The second endoprosthesis 200 can be positioned such that a distal end region of the second endoprosthesis 200 extends distal to the bifurcation 12 in the radially constrained or contracted configuration and a proximal end region of the second endoprosthesis 200 extends proximal to the bifurcation 12 in the radially constrained or contracted configuration.

[0073] The second endoprosthesis 200 can be configured to transition from a radially contracted configuration to a radially expanded configuration. In at least some embodiments, the second endoprosthesis 200 can be self-biased toward the radially expanded configuration. In some embodiments, the second endoprosthesis 200 can be formed from a superelastic and / or shape-memory material, such as Nitinol. In some embodiments, the second endoprosthesis 200 can be constrained in the radially contracted configuration by the properties of the shape-memory material when the second endoprosthesis 200 is advanced into the first body lumen 10. In some embodiments, the second endoprosthesis 200 can be constrained in the radially contracted configuration by a delivery sheath surrounding the second endoprosthesis 200 when the second endoprosthesis 200 is advanced into the first body lumen 10. Other configurations, including combinations thereof, are also contemplated.

[0074] In some embodiments, the delivery sheath may be an elongate catheter or other tubular member suitable for and / or known in the art for delivering an endoprosthesis. The second endoprosthesis 200 may be disposed within the lumen of the delivery sheath in a radially constrained or contracted configuration. In the radially contracted configuration, the expandable framework may be substantially straight and / or fully extended. The second endoprosthesis 200 may be deployed from the delivery sheath using one or more known techniques, such as by retracting the delivery sheath proximally from the second endoprosthesis 200 to eject the second endoprosthesis 200 from the delivery sheath. Other techniques commonly known, but not described for brevity, may be used to deploy the second endoprosthesis 200 from the delivery sheath.

[0075] The method may include transitioning the second endoprosthesis 200 to a radially expanded configuration within the plurality of loops 130 and / or passages 150, as shown in Figure 7. In some embodiments, transitioning the second endoprosthesis 200 to a radially expanded configuration may include withdrawing and / or retracting a delivery sheath relative to the second endoprosthesis 200 to expose the second endoprosthesis 200 within the first body lumen 10 and / or within the plurality of loops 130 and / or passages 150, thereby allowing the second endoprosthesis 200 to radially expand.

[0076] In at least some embodiments, the second endoprosthesis 200 and / or expandable framework may be deployed within the first body lumen 10 extending through the stenosis to maintain and / or re-establish patency of the body lumen 10. In some embodiments, the second endoprosthesis 200 and / or expandable framework may be configured to expand at least a portion of the first body lumen 10 in a radially expanded configuration. For example, the second endoprosthesis 200 and / or expandable framework may be configured to exert a radially outward force against the wall of the first body lumen 10 and / or against a stenosis formed within the first body lumen 10.

[0077] In some embodiments, at least a portion of the second endoprosthesis 200 can be disposed within the plurality of loops 130 and / or passages 150 in the radially expanded configuration. In some embodiments, at least a portion of the second endoprosthesis 200 can extend away from the plurality of loops 130 and / or passages 150 when the second endoprosthesis 200 is disposed within the plurality of loops 130 and / or passages 150 in the radially expanded configuration.

[0078] In some embodiments, the second endoprosthesis 200 can be configured to engage the plurality of loops 130 and / or passages 150 in the radially expanded configuration. In the radially expanded configuration, the second endoprosthesis 200 can be configured to apply a radially outward force to the first endoprosthesis 100 and / or plurality of loops 130 in the helical configuration, thereby engaging and / or urging the first endoprosthesis 100 and / or plurality of loops 130 against the wall of the first body lumen 10. In some examples, a portion of the second endoprosthesis 200 extending between adjacent loops 130 can extend radially outward and contact the wall of the first body lumen 10.

[0079] In some embodiments, the second endoprosthesis 200 can be configured to expand at least a portion of the first body lumen 10 in the radially expanded configuration. For example, the second endoprosthesis 200 can be configured to exert a radially outward force on the wall of the first body lumen 10 in the radially expanded configuration. In some embodiments, the first endoprosthesis 100 and the second endoprosthesis 200 can be configured to extend beyond an opening to an adjacent body lumen (e.g., the second body lumen 20), as shown in FIG. 7 . In other words, the second endoprosthesis 200 can be configured to extend beyond the bifurcation 12 such that a first end region of the second endoprosthesis 200 is disposed within the first body lumen 10 upstream of the bifurcation 12 and a second end region of the second endoprosthesis 200 is disposed within the first body lumen 10 downstream of the bifurcation 12.

[0080] In some embodiments, the first end portion 110 of the first endoprosthesis 100 can extend away from the second endoprosthesis 200 generally parallel to a central longitudinal axis of the second endoprosthesis 200 when the second endoprosthesis 200 is disposed in a radially expanded configuration within the plurality of loops 130 and / or passages 150. In some embodiments, the first end portion 110 of the first endoprosthesis 100 can extend away from the second endoprosthesis 200 within the first body lumen 10 when the second endoprosthesis 200 is disposed in a radially expanded configuration within the plurality of loops 130 and / or passages 150.

[0081] In some embodiments, the second end portion 112 of the first endoprosthesis 100 can extend away from the second endoprosthesis 200 generally parallel to a central longitudinal axis of the second endoprosthesis 200 when the second endoprosthesis 200 is disposed in a radially expanded configuration within the plurality of loops 130 and / or passages 150. In some embodiments, the second end portion 112 of the first endoprosthesis 100 can extend away from the second endoprosthesis 200 within the first body lumen 10 when the second endoprosthesis 200 is disposed in a radially expanded configuration within the plurality of loops 130 and / or passages 150.

[0082] In one example, when the second endoprosthesis 200 is positioned in a radially expanded form within the multiple loops 130 and / or passages 150, the first end portion 110 of the first endoprosthesis 100 may extend into the first body lumen 10 upstream from the second endoprosthesis 200, and when the second endoprosthesis 200 is positioned in a radially expanded form within the multiple loops 130 and / or passages 150, the second end portion 112 of the first endoprosthesis 100 may extend into the first body lumen 10 downstream from the second endoprosthesis 200. In another example, when the second endoprosthesis 200 is positioned in a radially expanded form within the multiple loops 130 and / or passages 150, the first end portion 110 of the first endoprosthesis 100 may extend into the first body lumen 10 downstream from the second endoprosthesis 200, and when the second endoprosthesis 200 is positioned in a radially expanded form within the multiple loops 130 and / or passages 150, the second end portion 112 of the first endoprosthesis 100 may extend into the first body lumen 10 upstream from the second endoprosthesis 200.

[0083] After the second endoprosthesis 200 is deployed within the plurality of loops 130 and / or passageways 150, the second endoprosthesis 200 and polymer cover 220 (if present) may cooperate with the first endoprosthesis 100 to form a spiral fluid pathway around (e.g., outside) the second endoprosthesis 200 from an upper portion (e.g., upstream portion) of the first body lumen 10 to a lower portion (e.g., downstream portion) of the first body lumen 10, and from the second body lumen 20 to a lower portion (e.g., downstream portion) of the first body lumen 10. In at least some embodiments, the first endoprosthesis 100 may form a gap 30 between the exterior (e.g., outer surface) of the second endoprosthesis 200 and the wall of the first body lumen 10, and the gap 30 may form a spiral fluid pathway around the exterior (e.g., outer surface) of the second endoprosthesis 200. The gap 30 may be fluidly accessible from the second body lumen 20, thereby maintaining fluid flow from the second body lumen 20 along the spiral gap 30 within the first body lumen 10 when the first body lumen 10 is treated with the system.

[0084] In some embodiments, the first endoprosthesis 100, in cooperation with the second endoprosthesis 200 and the polymer cover 220 (if present), may externally provide a drainage path from the second body lumen 20 to the first body lumen 10 along and / or using a spiral fluid path around the exterior of the second endoprosthesis 200. In some embodiments, the first endoprosthesis 100 may include multiple drainage ports 140 formed along a middle portion of the first endoprosthesis 100. The multiple drainage ports 140 may be in fluid communication with the lumen 102 of the first endoprosthesis 100. The middle portion of the first endoprosthesis 100 including the multiple drainage ports 140 may be positioned beyond the opening to the second body lumen 20. The plurality of drainage ports 140 may allow fluid from the second body lumen 20 to access and / or enter the lumen 102 of the first endoprosthesis 100. Thus, in some embodiments, the first endoprosthesis 100 may be configured to provide a drainage path from the second body lumen 20 into the first body lumen 10 internally and / or through the lumen 102 of the first endoprosthesis 100. In some embodiments, the first endoprosthesis 100 may be configured to provide a drainage path from the second body lumen 20 to the first body lumen 10 both internally (e.g., through the lumen 102 of the first endoprosthesis 100) and externally (e.g., along the exterior of the first endoprosthesis 100 forming the gap 30 along the exterior of the second endoprosthesis 200).

[0085] Materials that may be used for the various components of the systems disclosed herein and their various elements may include those generally associated with medical devices. For simplicity, the following description will refer to systems. However, this is not intended to limit the devices and methods described herein, as this description may apply to other elements, members, components, or apparatuses disclosed herein, such as, but not limited to, the first endoprosthesis, the second endoprosthesis, the expandable framework, the polymer cover, etc., and / or elements or components thereof.

[0086] In some embodiments, the stent system and / or its components may be made from metals, alloys, polymers (some examples of which are disclosed below), metal-polymer composites, ceramics, combinations thereof, etc., or other suitable materials.

[0087] Some examples of suitable polymers include polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), polyoxymethylene (POM, e.g., DELRIN®), polyether block esters, polyurethanes, polypropylene (PP), polyvinyl chloride (PVC), polyether esters (e.g., DSM Engineering Plastics (ARNITEL®)), ether or ester-based copolymers (e.g., butylene / poly(alkylene ether) phthalates and / or other polyester elastomers such as HYTREL®), polyamides (e.g., DURETHAN® or CRISTAMID®), elastomeric polyamides, block polyamide / ethers, polyether block amides (PEBA), e.g., available under the trade name PEBAX®), ethylene vinyl acetate copolymers (EVA), silicones, polyethylene (PE). , MARLEX high density polyethylene, MARLEX low density polyethylene, linear low density polyethylene (e.g., REXELL®), polyester, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polytrimethylene terephthalate, polyethylene naphthalate (PEN), polyether ether ketone (PEEK), polyimide (PI), polyetherimide (PEI), polyphenylene sulfide (PPS), polyphenylene oxide (PP O), polyparaphenylene terephthalamide (e.g., KEVLAR®), polysulfone, nylon, nylon-12 (GRILAMID®), perfluoro(propyl vinyl ether) (PFA), ethylene vinyl alcohol, polyolefin, polystyrene, epoxy, polyvinyl chloride (PVdC), poly(styrene-b-isobutylene-b-styrene) (e.g., SIBS and / or SIBS 50A), polycarbonate, polyurethane silicone copolymers (e.g.,These may include Elast-Eon® or ChronoSil®, biocompatible polymers, other suitable materials, or mixtures, combinations, copolymers, and polymer / metal composites thereof. In some embodiments, the system and / or its components may be blended with a liquid crystal polymer (LCP). For example, the blend may contain up to about 6 percent LCP.

[0088] Some examples of suitable metals and alloys include stainless steels such as 304V, 304L, 316LV stainless steel; mild steel; nickel-titanium alloys such as linear elastic and / or superelastic nitinol; nickel-chromium-molybdenum alloys (e.g., UNS: N06625 such as INCONEL® 625, UNS: N06022 such as HASTELLOY® C-22®, UNS: N10276 such as HASTELLOY® C276®, other HASTELLOY® alloys), nickel-copper alloys (e.g., UNS: N04400 such as MONEL® 400, NICKELVAC® 400, NICORROS® 400), nickel-chromium-molybdenum alloys (e.g., UNS: N04400 such as MONEL® 400, NICKELVAC® 400, NICORROS® 400, etc. ... Other nickel alloys, such as nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R30035, such as MP35-N®), nickel-molybdenum alloys (e.g., UNS: N10665, such as 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; cobalt-chromium alloys; cobalt-chromium-molybdenum alloys (e.g., UNS: R30003, such as ELGILOY®, PHYNOX®); platinum-rich stainless steel; titanium; platinum; palladium; gold; combinations thereof, etc.; or any other suitable material.

[0089] In at least some embodiments, some or all of the stent system and / or its components may be doped with, fabricated from, or otherwise include a radiopaque material. A radiopaque material is understood to be a material that can produce a relatively bright image on a fluoroscopic screen or another imaging technique (e.g., ultrasound) during a medical procedure. This relatively bright image aids the user of the system in determining its location. Some examples of radiopaque materials may include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloys, polymeric materials filled with radiopaque fillers, and the like. Additionally, other radiopaque marker bands and / or coils may also be incorporated into the system design to achieve the same results.

[0090] In some embodiments, systems and / or other elements disclosed herein are provided with a degree of magnetic resonance imaging (MRI) compatibility. For example, systems and / or components or portions thereof may be made from materials that do not substantially distort images and do not introduce substantial artifacts (e.g., gaps in the image). For example, certain ferromagnetic materials may be unsuitable because they may introduce artifacts in MRI images. Systems or portions thereof may also be made from materials that can be imaged by MRI machines. Some materials that exhibit these properties include, for example, tungsten, cobalt-chromium-molybdenum alloys (e.g., UNS:R30003, such as ELGILOY® and PHYNOX®), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS:R30035, such as MP35-N®), nitinol, etc.

[0091] In some embodiments, the systems and / or other elements disclosed herein may include a fabric material disposed on or within the structure. The fabric material may be composed of a biocompatible material, such as a polymeric material or a biomaterial, adapted to promote tissue ingrowth. In some embodiments, the fabric material may include a bioabsorbable material. Some examples of suitable fabric materials may include, but are not limited to, polyethylene glycol (PEG), nylon, polytetrafluoroethylene (PTFE, ePTFE), polyolefin materials such as polyethylene, polypropylene, polyester, polyurethane, and / or mixtures or combinations thereof.

[0092] In some embodiments, the systems and / or other elements disclosed herein may include and / or be formed from textile materials. Some examples of suitable textile materials include synthetic yarns, which may be flat, molded, twisted, woven, preshrunk, or unshrunk. Synthetic biocompatible yarns suitable for use in the present disclosure include, but are not limited to, polyesters, including polyethylene terephthalate (PET) polyester, polypropylene, polyethylene, polyurethane, polyolefins, polyvinyl, polymethyl acetate, polyamide, naphthalene dicarboxylene derivatives, natural silk, and polytetrafluoroethylene. Additionally, at least one of the synthetic yarns may be a metal yarn, or a glass or ceramic yarn or fiber. Useful metal yarns include yarns made from or including stainless steel, platinum, gold, titanium, tantalum, or Ni-Co-Cr-based alloys. The yarns may further include carbon, glass, or ceramic fibers. Desirably, the yarns are made from a thermoplastic material, including, but not limited to, polyester, polypropylene, polyethylene, polyurethane, polynaphthalene, polytetrafluoroethylene, and the like. The yarns may be of the multifilament, monofilament or spun type. The yarn type and denier selected may be selected to form a biocompatible and implantable prosthesis, and more particularly, a vascular structure, having desirable properties.

[0093] In some embodiments, the systems and / or other elements disclosed herein may include and / or be treated with a suitable therapeutic agent. Some examples of suitable therapeutic agents include antithrombotic agents (such as heparin, heparin derivatives, urokinase, and PPack (dextrophenylalanine proline arginine chloromethyl ketone)); antiproliferative agents (such as enoxaparin, angiopeptin, monoclonal antibodies capable of inhibiting smooth muscle cell proliferation, hirudin, and acetylsalicylic acid); anti-inflammatory agents (such as dexamethasone, prednisolone, corticosterone, budesonide, estrogen, sulfasalazine, and mesalamine); antitumor / antiproliferative / antimitotic agents (such as paclitaxel, 5-fluorouracil, cisplatin, vinblastine, vincristine, epothilones, endostatin, angiostatin, and thymidine kinase inhibitors); anesthetics (such as lidocaine, bupivacaine, and ropivacaine); anticoagulants (such as D-Phe-Pro-Arg chloromethyl ketone, RGD peptide-containing compounds, heparin antithrombin compounds, platelet receptor antagonists, antithrombin antibodies, antiplatelet receptor antibodies, aspirin, prostaglandin inhibitors, platelet inhibitors and antiplatelet peptides; vascular cell growth promoters (growth factor inhibitors, growth factor receptor antagonists, transcription activators and translation promoters, etc.); vascular cell growth inhibitors (growth factor inhibitors, growth factor receptor antagonists, transcription repressors, translation repressors, replication inhibitors, inhibitory antibodies, antibodies against growth factors, bifunctional molecules consisting of a growth factor and a cytotoxin, bifunctional molecules consisting of an antibody and a cytotoxin); immunosuppressants (olimus drugs, rapamycin analogs, macrolide antibiotics, biolimus, everolimus, zotarolimus, temsirolimus, picrolimus, novolimus, myolimus, tacrolimus, sirolimus, pimecrolimus, etc.); cholesterol-lowering drugs; vasodilators; drugs that interfere with endogenous vasoactive mechanisms.

[0094] It should be understood that this disclosure is, in many respects, merely illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of steps, without exceeding the scope of the disclosure. This may include, to the extent appropriate, using any of the features of one example embodiment in other embodiments. The scope of the disclosure is, of course, defined in the language in which the appended claims are expressed.

Claims

1. 1. A system for maintaining patency of a body lumen, comprising: a first endoprosthesis having a lumen extending from a first end to a second end, the first endoprosthesis being configured to transition from a straight configuration to a helical configuration forming a plurality of loops; a second endoprosthesis configured to transition from a radially contracted configuration to a radially expanded configuration; the plurality of loops defining a passageway having an inner diameter; At least a portion of the second endoprosthesis is disposed within the passageway in the radially expanded configuration.

2. The system of claim 1 , wherein at least a portion of the second endoprosthesis extends away from the passageway when the second endoprosthesis is disposed in the radially expanded configuration within the passageway.

3. The system of claim 1 or 2, wherein at least a portion of the first endoprosthesis extends away from the plurality of loops.

4. 4. The system of claim 3, wherein when the second endoprosthesis is positioned within the passage in the radially expanded configuration, a first end portion of the first endoprosthesis extends away from the second endoprosthesis in a direction transverse to a central longitudinal axis of the second endoprosthesis.

5. 5. The system of claim 3, wherein when the second endoprosthesis is positioned within the passage in the radially expanded configuration, the second end portion of the first endoprosthesis extends away from the second endoprosthesis generally parallel to a central longitudinal axis of the second endoprosthesis.

6. the second endoprosthesis has an outer diameter in the radially expanded configuration; The system of claim 1 , wherein the outer diameter of the second endoprosthesis is within 20% of the inner diameter of the passageway.

7. The system of any one of claims 1 to 6, wherein the plurality of loops define an outer diameter of about 6 French to about 12 French.

8. The system of claim 1 , wherein the first endoprosthesis is self-biased toward the helical configuration.

9. The system of claim 1 , wherein the second endoprosthesis is self-biased toward the radially expanded configuration.

10. The system of claim 1 , wherein the second endoprosthesis includes a polymeric covering extending along at least a portion of the length of the second endoprosthesis.

11. The system of claim 1 , wherein the first endoprosthesis includes a corrugated portion disposed between the first end and the plurality of loops.

12. The system of claim 1 , wherein the first endoprosthesis includes one or more drainage holes extending through a sidewall of the first endoprosthesis.

13. The system of claim 1 , wherein the first endoprosthesis includes one or more anti-migration elements extending radially outward from the first endoprosthesis.

14. The system of claim 1 , wherein the first endoprosthesis is formed from a polymeric material.

15. 1. A method for maintaining patency of a body lumen, comprising: advancing a first endoprosthesis into a first body lumen in a straight configuration; deploying the first endoprosthesis into a helical configuration forming a plurality of loops within the first body lumen; advancing a second endoprosthesis into the first body lumen in a radially collapsed configuration; transitioning the second endoprosthesis within the plurality of loops to a radially expanded configuration.

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