Patent Description:
Stents may be used to maintain a pathway within a bodily lumen. However, in many bodily areas, such as the esophageal tract, such stents are susceptible to migration from the area in which originally deployed. Such migration is generally undesired because the stent may damage surrounding tissue and may no longer maintain a pathway of the desired lumen. One solution to stent migration is providing a stent with openings that facilitate tissue ingrowth. However, tissue ingrowth is problematic when the stent is designed for temporary deployment. When tissue ingrowth occurs, removal and/or repositioning of the stent is difficult or dangerous.

<CIT> describes a bioabsorbable implant including an elongated metallic element including more than <NUM>% metal substantially free of rare earth metals, with the elongated metallic element defining at least a portion of the bioabsorbable implant. A hybrid stent may include thin proximal and distal ring segments made from a biostable and radio-opaque material, a larger center ring segment including, e.g., a plurality of rings made of a bioabsorbable magnesium alloy or a helical continuous sinusoid, and filament connectors,.

The invention is set out in claim <NUM> and preferred features are set out in the dependent claims.

In one aspect, the present disclosure provides a stent with a tubular stent body having a lumen extending therethrough. The stent may further include an anchor portion attached to an end of the tubular stent body, where the lumen continues through the anchor portion, and where the anchor portion includes at least one opening configured to facilitate tissue ingrowth. The anchor portion may be detachable from the tubular stent body while the stent is in a deployed state.

The embodiments will be further described in connection with the attached drawings. It is intended that the drawings included as a part of this specification be illustrative of the exemplary embodiments and should in no way be considered as a limitation on the scope of the present disclosure. Indeed, the present disclosure specifically contemplates other embodiments not illustrated but intended to be included in the claims.

The embodiments illustrated herein can be used in any portion of the body benefiting from a removable or repositionable indwelling medical device, such as a stent, including but not limited to, the gastrointestinal region, esophageal region, duodenum region, biliary region, colonic region, as well as any other bodily region or field, and they are not limited to the sizes or shapes illustrated herein.

Throughout, patients are not limited to being a human being, and indeed animals and others are contemplated. Users contemplated throughout the disclosure may be anyone or thing capable of using the device, including but not limited to a human being (e.g., a medical professional) and machine.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the present document, including definitions, will control. Preferred methods and materials are described below, although methods and materials similar or equivalent to those described herein can be used in practice or testing of the present invention. The materials, methods, and examples disclosed herein are illustrative only and not intended to be limiting.

The invention is described with reference to the drawings in which like elements are referred to by like numerals. The relationship and functioning of the various elements of this invention are better understood by the following detailed description. However, the embodiments of this invention are not limited to the embodiments illustrated in the drawings. It should be understood that the drawings are not to scale, and in certain instances details have been omitted which are not necessary for an understanding of the present invention, such as conventional fabrication and assembly.

As used in the specification, the terms proximal and distal should be understood as being in the terms of a physician delivering the medical device to a patient. Hence the term "distal" means the portion of the medical device that is farthest from the physician and the term "proximal" means the portion of the medical device that is nearest to the physician.

<FIG> is an illustration showing a stent <NUM> with a stent body <NUM> and an anchor portion <NUM>, and <FIG> is a magnified view showing a proximal end of <FIG>. While such a device can be used in any suitable application (and within any body lumen or other location of a patient body), the stent <NUM> of <FIG> is particularly suitable for use in the GI tract, including biliary and esophageal locations. For example, when treating benign strictures in the esophagus a removable stent is often desired, but existing removable stents do not provide sufficient anchorage and thus tend to migrate. The stent <NUM> provides a solution to this issue because it includes the stent body <NUM> (e.g., a covered stent portion) that may be removed after a predetermined period of time in combination with the anchor portion <NUM> that provides sufficient anchoring. As described in more detail below, the anchor portion <NUM> may be detachable from the stent body <NUM> such that the stent body <NUM> can be removed from a patient body, leaving the anchor portion <NUM> behind. The anchor portion <NUM> may remain in the patient body permanently, may be removed separately, and/or may at least partially degrade over time due to its material composition, as described in more detail below.

The stent body <NUM> may include a generally-tubular shape with a proximal end <NUM>, a distal end <NUM>, and a lumen extending therethrough for providing an interior passage from the proximal end <NUM> to the distal end <NUM>. The lumen <NUM> may continue through the anchor portion <NUM>, which may also be generally-tubular in shape. As shown, the anchor portion <NUM> may be attached to an end of the stent body <NUM> (e.g., the proximal end, as shown, or the distal end), and in some embodiments an anchor portion <NUM> may be attached to each of the proximal end <NUM> and distal end <NUM> (e.g., as shown in <FIG>). Including an anchor portion at the proximal end <NUM> may be particularly advantageous in the GI tract due to the flow-direction of food and other GI contents. To prevent tissue ingrowth through the walls of the stent body <NUM>, the stent body <NUM> may be covered, coated, or otherwise sealed. For example, the stent body <NUM> may include a silicone membrane covering, although other materials are contemplated, to seal the exterior surface of the stent body <NUM>. In contrast, the anchor portion <NUM> may include one or more openings, cells, or other spaces or cavities to promote tissue ingrowth such that the anchor portion <NUM> becomes sufficiently anchored in an appropriate position within the patient body, thus preventing migration of the stent <NUM>.

The stent body <NUM> may be any suitable stent structure, such as a self-expanding stent body or a body that expands under pressures or other influence from another device, such as an inflatable balloon at the tip of a balloon catheter. One example of an exemplary stent body is a self-expanding woven or braided stent body, such as a woven stent body formed from a plurality of wires <NUM> extending in opposite-helical directions around the outer perimeter of the stent body's outer surface. Certain examples of woven stent bodies are described in more detail in <CIT>. One particular example is the Evolution® stent commercialized by Cook® Medical.

In other embodiments, the stent body <NUM> may be formed by a Z-stent design or Gianturco stent design (commercialized by Cook® Medical). In this instance, the stent body <NUM> may include a series of substantially straight segments or struts interconnected by a series of bent segments or bends. The bent segments may include acute bends or apices. The segments may be arranged in a zigzag configuration where the straight segments are set at angles relative to one another and are connected by the bent segments. The first stent may additionally or alternatively be formed of another stent pattern, such as an annular or helical stent pattern.

Without limitation, the stent segments and/or woven wires mentioned herein may be made from standard medical grade stainless steel or from nitinol or other shape-memory materials, and/or other metals/polymers in either a permanent or bioabsorbable design. It is also contemplated that the stent body <NUM> may be something other than a self-expanding stent, such as a substantially rigid or obstinate tube formed of a biocompatible material and/or any other suitable device for temporarily or permanently providing support to a body lumen.

The anchor portion <NUM> may incorporate any of the structures described with respect to the stent body <NUM> (e.g., the anchor portion <NUM> may incorporate wires <NUM> woven in opposite helical directions in certain exemplary embodiments). In some embodiments, the anchor portion <NUM> may be at least partially formed of a biodegradable and/or bioabsorbable material, such as a material that degrades at a known rate (e.g., hours, days, weeks, or months as required) when the anchor portion <NUM> is located inside a patient body. For example, without limitation, the frame member(s) (e.g., woven wires or other structure-providing device) may be formed of the materials and techniques discussed in <CIT>.

For example, one or more bioabsorbable polymer materials may be used to form the anchor portion <NUM>. Using polymer materials provide the ability to enhance certain characteristics such as flexibility, compliance, and rate of bioabsorption. The properties of the bioabsorbable polymers may differ considerably depending on the nature and amounts of the comonomers, if any, employed and/or the polymerization procedures used in preparing the polymers. Biodegradable polymers that can be used to form the support frame of a medical device (such as the anchor portion <NUM>), or can be coated on a frame member, include a wide variety of materials. Examples of such materials, include but are not limited to, polyesters, polycarbonates, polyanhydrides, poly(amino acids), polyimines, polyphosphazenes and various naturally occurring biomolecular polymers, as well as co-polymers and derivatives thereof. Certain hydrogels, which are cross-linked polymers, can also be made to be biodegradable. These include, but are not necessarily limited to, polyesters, poly(amino acids), copoly(ether-esters), polyalkylenes oxalates, polyamides, poly(iminocarbonates), polyorthoesters, polyoxaesters, polyamidoesters, polyoxaesters containing amido groups, poly(anhydrides), polyphosphazenes, poly-alpha-hydroxy acids, trimethlyene carbonate, poly-beta-hydroxy acids, polyorganophosphazines, polyanhydrides, polyesteramides, polyethylene oxide, polyester-ethers, polyphosphoester, polyphosphoester urethane, cyanoacrylates, poly(trimethylene carbonate), poly(iminocarbonate), polyalkylene oxalates, polyvinylpyrolidone, polyvinyl alcohol, poly-N-(<NUM>-hydroxypropyl)-methacrylamide, polyglycols, aliphatic polyesters, poly(orthoesters), poly(ester-amides), polyanhydrides, modified polysaccharides and modified proteins. Some specific examples of bioabsorbable materials include poly(epsilon-caprolactone), poly(dimethyl glycolic acid), poly(hydroxyl butyrate), poly(p-dioxanone), polydioxanone, PEO/PLA, poly(lactide-co-glycolide), poly(hydroxybutyrate-covalerate), poly(glycolic acid-eo-trimethylene carbonate), poly(epsilon-caprolactone-co-p-dioxanone), poly-Lglutamic acid or poly-L-lysine, polylactic acid, polylactide, polyglycolic acid, polyglycolide, poly(D,L-lactic acid), L-polylactic acid, poly(glycolic acid), polyhydroxyvalerate, cellulose, chitin, dextran, fibrin, casein, fibrinogen, starch, collagen, hyaluronic acid, hydroxyethyl starch, and gelatin.

If a metallic bioabsorbable material is used, it may be selected from a first group consisting of: magnesium, titanium, zirconium, niobium, tantalum, zinc and silicon. Mixtures and alloys of metallic bioabsorbable materials including those selected from the group in the preceding sentence are also contemplated. In some embodiments, the metallic bioabsorbable material can be an alloy of materials from the first group and a material selected from a second group consisting of: lithium, sodium, potassium, calcium, iron and manganese. Without being limited to theory, it is believed that the metallic bioabsorbable material from the first group may form a protective oxide coat upon exposure to blood or interstitial fluid. The material from the second group is preferably soluble in blood or interstitial fluid to promote the dissolution of an oxide coat. The bioabsorption rate, physical properties and surface structure of the metallic bioabsorbable material can be adjusted by altering the composition of the alloy. In addition, other metal or non-metal components, such as gold, may be added to alloys or mixtures of metallic bioabsorbable materials. Some preferred metallic bioabsorbable material alloy compositions include lithium-magnesium, sodium-magnesium, and zinctitanium, which can optionally further include gold. The frame members themselves, or any portion of the anchor portion <NUM>, can be made from one or more metallic bioabsorbable materials, and can further include one or more non-metallic bioabsorbable materials, as well as various non-bioabsorbable materials. The bioabsorbable material can be distributed throughout the entirety of the frame member(s), or any localized portion thereof, in various ways. In some embodiments, the frame member(s) can include a bioabsorbable material or a non-bioabsorbable material as a "core" material, which can be at least partially enclosed by other materials. The frame can also have multiple bioabsorbable materials stacked on all or part of the surface of a non-bioabsorbable core material. The frame member(s) can also include a surface area presenting both a bioabsorbable material and a non-bioabsorbable material.

In some embodiments, the anchor portion <NUM> may have a diameter <NUM> (e.g., an outer diameter) that is larger than a diameter <NUM> of the stent body <NUM>. Advantageously, the larger diameter <NUM> of the anchor portion <NUM> may ensure that appropriate contact and pressure is experienced between the anchor portion <NUM> and an inner surface of a body lumen to prevent migration, promote tissue ingrowth, promote bioabsorption, etc. The diameter <NUM> of the anchor portion <NUM> may be at least about <NUM>% larger than the diameter <NUM> of the central portion <NUM> of the stent body <NUM>, such as about <NUM>% greater. In one non-limiting embodiment for use in a human esophagus, the outer diameter <NUM> of the anchor portion <NUM> may be about <NUM>,<NUM> (<NUM> ") and the outer diameter <NUM> of the central portion <NUM> may be about <NUM> (<NUM>"). When the unit inches (") is mentioned in the following, the conversion is <NUM> "=<NUM>,<NUM>.

Optionally, the stent body <NUM> may include a proximal flange <NUM> and/or a distal flange <NUM> that have diameters greater than the diameter <NUM> of the central portion. As shown, the diameter of the flanges <NUM>, <NUM> is approximately equal to the diameter <NUM> of the anchor portion <NUM>, but this is not required. The flanges <NUM>, <NUM> may be advantageous to enhance anchorage of the stent body <NUM> when it is deployed and to accommodate engagement with the anchor portion <NUM>. While not shown in the depicted embodiment, it is contemplated that the flanges <NUM>, <NUM> may be sized such that their inner diameters are slidably received by the inner diameter of the anchor portion <NUM>, or vice versa. To prevent tissue ingrowth through the outer walls of the flanges <NUM>, <NUM>, the flanges <NUM>, <NUM> may be covered (as described above), but it is also contemplated that limited tissue ingrowth may be desirable through the flanges <NUM>, <NUM> in some situations (e.g., to prevent migration of the stent body <NUM> when the anchor portion <NUM> degrades).

While the central portion <NUM> may have a smaller diameter (as shown) than the above-described flanges and/or anchor portions, it is contemplated that the central portion <NUM> may be more rigid than other portions or otherwise configured to provide a relatively high radial force (e.g., to press back benign tumors), while the flange <NUM>, <NUM> and/or the anchor portion <NUM> may be relatively compliant to provide comfort to a patient (particularly when the flange <NUM>, <NUM> and/or the anchor portion <NUM> is configured to abut patient tissue (e.g., healthy patient tissue).

As shown in <FIG>, the anchor portion <NUM> may be substantially shorter in length than the stent body <NUM>. For example, the anchor portion <NUM> may have a length that is about <NUM>% of the length of the stent body <NUM>, or less. In one non-limiting embodiment, the length of the anchor portion <NUM> may be about <NUM>" and the length of the stent body <NUM> may be about <NUM>", but other dimensions are contemplated for patients of different sizes, different medical conditions, different target body lumens, etc..

Referring to <FIG>, it is also contemplated that the anchor portion <NUM> may be longer than <NUM>% of the length of the stent body <NUM>, particularly when a high-degree of anchoring is desirable. Further, like the stent body <NUM>, the anchor portion <NUM> may have different diameters along its length, which is illustrated by the flange <NUM> on the proximal end <NUM> of the anchor portion <NUM> of <FIG>.

As described above, the anchor portion <NUM> may be detachable from the stent body <NUM>. Preferably, such detachability can occur when the stent <NUM> is in a deployed state located within the patient body. Advantageously, the anchor portion <NUM> can be left in the body (or it can disintegrate prior to stent removal) while the stent body <NUM> can be removed. This detachability may be provided by the attachment mechanism that initially secures the stent body <NUM> to the anchor portion <NUM>, the material of the stent body <NUM> and/or the anchor portion <NUM>, by a separate medical instrument, etc..

For example, referring to <FIG>, the stent body <NUM> and the anchor portion <NUM> may initially (e.g., prior to and during deployment) be attached and secured to one another by interlocking one or more wires <NUM> forming stent body <NUM> with one or more wires <NUM> forming the anchor portion <NUM>. While the attachment may be relatively secure prior to spending a predetermined amount of time deployed within the body, at least one of the wires <NUM>, <NUM> (specifically the wires <NUM> of the anchor portion <NUM> in certain exemplary embodiments) may weaken over time due to degradation (e.g., by being formed of a bioabsorbable material). After a predetermined amount of time, the wire <NUM> may be sufficiently degraded such that the wires <NUM> are easy broken, or are no longer present, when it comes time for removal of the stent body <NUM>. This embodiment may be advantageous since no additional components are needed to attach the two components together, thus simplifying manufacturing and certain medical procedures. While all the wires <NUM> may be made of the same material, it is also contemplated that the wires <NUM> that interlock the wires <NUM> may degrade faster than other wires of the anchor portion <NUM>, which may be advantageous where it is desirable to detach the two elements while the anchor portion <NUM> is still in-tact enough to provide support to a body lumen.

In other embodiments, including the embodiment depicted in <FIG>, a separate component, such as a ripcord (or other strand), a clamp, a tie, or any other suitable fastening device may be used to initially secure and attach the stent body <NUM> with the anchor portion <NUM>. In the depicted embodiment, a cord <NUM> (which may be a ripcord or any other suitable strand) is used. The cord <NUM> may extend through openings of one or both of the stent body <NUM> and the anchor portion <NUM>. Alternatively (and as shown), the cord <NUM> may extend only through openings in the crown <NUM> of the stent body <NUM>, which may be advantageous for ease of manufacturing/assembly and/or for consistency in removal of the cord <NUM>. The attachment is accomplished in this embodiment because the cord <NUM> prevents the protrusions of the crown <NUM> from being pulled away from the respective openings <NUM> formed by wires <NUM> of the anchor portion <NUM>.

To detach the anchor portion <NUM> from the stent body <NUM>, the cord <NUM> can be removed. For example, the cord <NUM> may be formed of a biodegradable material to allow detachment of the anchor portion <NUM> from the stent body <NUM> after a predetermined amount of time in the body (e.g., due to degradation of the cord <NUM>). It is contemplated that the cord <NUM> may be configured to degrade faster than the material of the anchor portion <NUM>, and thus the anchor portion <NUM> can be left in the patient body for additional time to provide structure to the body lumen even after the stent body <NUM> is separated and removed. Additionally or alternatively, the cord <NUM> can be cut (e.g., with a separate cutting device, such as a knife or scissors) and then pulled out of the patient, leaving the stent body <NUM> and the anchor portion <NUM> separated. As shown in <FIG>, an optional handle <NUM> (shown in <FIG> but only labeled in <FIG>) may be included to facilitate removal of the cord <NUM>. For example, a separate medical instrument may be configured to find and grasp the handle <NUM>, and then pull on the handle <NUM> to remove the cord <NUM>.

<FIG> shows an embodiment with a cord <NUM> that engages a first string <NUM> and a second string <NUM>. In particular, the cord <NUM> alternates between interlocking with the first string <NUM> and the second string <NUM> as it extends around the circumference of the stent <NUM> at a junction <NUM> between the stent body <NUM> and the anchor portion <NUM>. The first string <NUM> may be secured to the anchor portion <NUM> (e.g., due to extending through the openings <NUM> formed by the wires <NUM>), and the second string <NUM> may similarly be secured to the crown <NUM> of the stent body <NUM> (e.g., it may extend through openings formed by the crown <NUM>). It is contemplated that the first string <NUM> and the second string <NUM> may be one continuous strand, but they are separate strands in the depicted embodiment. Further, it is contemplated that neither of, or only one of, the first string <NUM> and the second string <NUM> may be included. For example, if neither of the first string <NUM> and the second string <NUM> is included, the cord <NUM> extend through the openings <NUM> and openings of the crown <NUM> in a zig-zag patter. If only one of the strings is included, the cord <NUM> may directly secure to one of the anchor portion <NUM> and the stent body <NUM> but may be secured to the other by way of a string, for example.

To detach the anchor portion <NUM> from the stent body <NUM>, at least one of the anchor portion <NUM>, the first string <NUM>, the second string <NUM>, and the cord <NUM> (or even the stent body <NUM>) may degrade during its time in the body due to including a bioabsorbable material, and/or at least one of those components can be broken (e.g., cut with a cutting device). In one exemplary embodiment, the first string <NUM> is configured to be cut and removed or weaken by degradation to detach the anchor portion <NUM> from the remainder of the stent <NUM>. The second string <NUM> and the cord <NUM> may then function to at least partially collapse an end of the stent body <NUM> for ease of removal, as shown in <FIG>.

<FIG> shows an intentional force being applied to the second string <NUM> and/or the cord <NUM> by way of a grasping strand <NUM>. The grasping strand <NUM> may include an optional handle <NUM>, as shown. The force may be transferred to the crown <NUM> of the stent body <NUM> through the second string <NUM> (or another string). Particularly when the flange <NUM>, the crown <NUM>, and/or other end structure of the stent body <NUM> is relatively compliant, such a tension may provide a drawstring effect, thus pulling the diameter of the end of the stent body <NUM> inwards towards a central point along the stent's longitudinal axis. This collapsing feature may be limited to the end of the stent body <NUM> (e.g., the crown or flange), or it may extend along the central portion of the stent body <NUM>. Thus, at least one location of the stent body <NUM>, and preferably a location with a maximum diameter when in a default state, decreases in diameter in a collapsed state initiated by tension in the cord <NUM> and the second string <NUM>. Advantageously, this decrease in diameter/size may facilitate removal of the stent body <NUM> from the patient body without requiring an invasive removal procedure. A similar feature is described in <CIT>, filed as <CIT>.

To further illustrate, <FIG> shows the proximal flange <NUM> in a collapsed state after the stent body <NUM> has been separated from the anchor portion <NUM>. As shown, the cord <NUM> may extend through the lumen <NUM> of the anchor portion <NUM> when being tensioned by a medical professional and/or a medical device that engages the cord <NUM>. The outer diameter of the flange <NUM> may collapse to the extent that it can freely move through the lumen <NUM> of the anchor portion <NUM>. The diameter <NUM> of the central portion <NUM> of the stent body can also collapse to some extent, or it may simply be small enough to begin with where it does not inhibit removal of the stent body <NUM> through the lumen <NUM> of the anchor portion <NUM>.

While not shown, more than one string may be included to provide a collapsing effect at more than one location. For example, the proximal end <NUM> and the distal end <NUM> (<FIG>) of the stent body <NUM> may each be associated with a string that acts as a drawstring when pulled, and/or additional strings may be placed along the length of the stent body <NUM> between the distal end <NUM> (<FIG>) and the proximal end <NUM>. Further, it is contemplated that only one strand (e.g., the second string <NUM> or the cord <NUM>) may be necessary to provide the drawstring effect. Additionally, it is contemplated that one pull of one cord or string (e.g., a pull of the cord <NUM>) may simultaneously accomplish both of (<NUM>) collapsing a diameter of a stent body, and also (<NUM>) separation of one portion of the stent from another (e.g., releasing the anchor portion <NUM> from the stent body <NUM>).

As shown in <FIG>, a delivery system <NUM> may be provided to facilitate deployment of the stent <NUM>. Without limitation, the delivery system <NUM> may include a sheath <NUM> for constricting the stent <NUM> during deployment to a target area in the body, a plunger <NUM> to press the stent <NUM> into the sheath <NUM> prior to deployment, an inner tube <NUM> that may extend through the sheath <NUM> and stent <NUM> to guide the device during deployment and/or provide fluid communication to a body area from a proximal location, and an adaptor <NUM> (where the adapter may be a luer-lock adapter used to facilitate attachment to a syringe to facilitate fluid passage). One example of a stent delivery system is the system provided with an Evolution® Esophageal Controlled-Release Stent (commercialized by Cook® Medical). The stent <NUM> is optimally packaged with the delivery system <NUM> during manufacturing or otherwise prior to delivery to a medical facility, but alternatively a medical professional may place the stent <NUM> in the delivery system <NUM> on-site prior to a medical procedure.

<FIG> shows the stent <NUM> and delivery system <NUM> in a storage state. As depicted, the sheath <NUM> surrounds the majority of the stent <NUM>, and all of (or nearly all of) the stent body <NUM> (not shown) is in a constrained state within the sheath <NUM>. The anchor portion <NUM> is depicted as being located at least partially outside the sheath <NUM> in an unconstrained state. This condition may be suitable for packaging and storage where the anchor portion <NUM> is not formed of a material with shape-recovery characteristics capable of retaining a proper "deployed" or default shape and state after remaining constrained within the sheath for a long time period (e.g., days, weeks, months, or even years). For example, while the stent body <NUM> may be formed of a nitinol or another suitable material with a high degree of shape-memory, the anchor portion <NUM> may formed of a different material selected primarily for its bioabsorbability rather than its mechanical characteristics, and therefore it may lack sufficient shape-memory to remain within the sheath <NUM> for days or weeks (or longer) without permanently changing its default shape due to plastic deformation. However, by leaving the anchor portion <NUM> in a default (substantially non-constrained) state during packaging and storage, its shape characteristics will be retained.

Referring to <FIG>, the delivery system <NUM> may include a funnel <NUM> located at a proximal end <NUM> to assist loading the proximal end of the stent <NUM>, particularly the anchor portion <NUM>, to within the sheath <NUM>. As shown, the funnel <NUM> is located adjacent the proximal end of the stent body <NUM>, and the proximal end of the stent body <NUM> expands in diameter as it extends away from the funnel <NUM> until reaching the anchor portion <NUM>, which is in a default (substantially non-constrained) state. At a selected time period before the stent <NUM> is to be deployed (e.g., minutes, hours, or even several days prior to deployment), the proximal end <NUM> of the stent body <NUM> along with the anchor portion <NUM> may be moved to at least partially into the sheath <NUM> by operating a plunger <NUM>, which typically includes a pusher (e.g., a friction sleeve) that forces the stent <NUM> into the sheath <NUM> when moved distally with respect to the sheath <NUM>. Since the stent <NUM> is already partially pre-loaded into the sheath <NUM>, and since loading the remainder of the stent requires only a simple motion of the plunger <NUM>, the remainder of the loading can easily and efficiently be accomplished by a medical professional at a medical facility rather than prior to on-site delivery.

Referring now to <FIG>, in addition to the examples described above (or as an alternative), any other suitable removable/releasable attachment mechanism may be additionally or alternatively included for separating the stent body <NUM> from the anchor portion <NUM>. Referring to <FIG>, it is contemplated that a crown tip <NUM> of at least one of the stent body <NUM> and the anchor portion <NUM> may be bent outward. As shown in <FIG>, the bend may case the end of the crown tip <NUM> to extend through an opening <NUM> in the anchor portion <NUM> (and, notably, the bent crown tip may alternatively be included as a portion of the anchor portion <NUM>). As shown in <FIG>, a pin <NUM> may be inserted through the opening <NUM> defined by the end of the crown tip <NUM> to retain the end of the crown tip <NUM> in the opening <NUM>. The pin <NUM> may alternatively be a string (e.g., a drawstring) or another feature. In certain embodiments, for example, pulling a drawstring (such as the grasped strand <NUM> shown in <FIG>) may have a dual purposes: (<NUM>) removing the pin <NUM> and/or otherwise detaching the anchor portion <NUM> from the stent body <NUM>, and (<NUM>) causing the stent body <NUM> to enter a collapsed state.

In some embodiments, the anchor portion <NUM> may be secured to the stent portion <NUM> without the use of a string or pin. For example, in some embodiments, the crown tip <NUM> may have one or more wings <NUM> (shown in two of the many possible orientations in <FIG>). The crown tip <NUM> may be relatively compliant such that the wings <NUM> deform as the crown tip <NUM> is placed into an opening of another component (e.g., the opening <NUM> shown in <FIG>) such that the crown tips <NUM> are secured via clipping action. It is contemplated that the bend orientation of the crown tips <NUM> (as shown in <FIG>) may be sufficient for radial clipping even if wings are not included, but the wings <NUM> may provide enhancement.

Another embodiment is shown in <FIG>. As shown, the anchor portion <NUM> includes a set of eyelets <NUM>. Additionally or alternatively, the stent portion <NUM> may include similar or identical eyelets. The eyelets <NUM> may be formed integrally with the remainder of the anchor portion <NUM> (e.g., by twisting the wire or other material forming the anchor portion <NUM>). As shown, a cord <NUM> may extend through the eyelets <NUM> (and also through openings in the stent body <NUM>) to hold the components together. If and when detachment is desirable, the cord <NUM> may be removed with any suitable process (e.g., via one or more of the methods described above). For example (which is not limiting), the cord may be formed with a biodegradable material that dissolves over time.

While not shown, it is further contemplated that a lockstitch may be used (e.g., such that one pull of a string releases the components from one another).

Claim 1:
A stent (<NUM>) comprising:
a tubular stent body (<NUM>) having a lumen extending therethrough; and
an anchor portion (<NUM>) attached to an end of the tubular stent body, wherein the lumen continues through the anchor portion (<NUM>), and wherein the anchor portion includes at least one opening configured to facilitate tissue ingrowth,
wherein the anchor portion (<NUM>) is detachable from the tubular stent body (<NUM>) while the stent is in a deployed state,
the stent further comprising at least one strand (<NUM>, <NUM>, <NUM>) securing the end of the tubular stent body to the anchor portion wherein the at least one strand (<NUM>, <NUM>, <NUM>) is at least partially formed of a bioabsorbable material such that the at least one strand weakens over time when the stent is deployed in a patient body,
wherein the anchor portion (<NUM>) includes a bioabsorbable material configured to degrade at a predetermined rate, and the at least one strand (<NUM>, <NUM>, <NUM>) is configured to degrade faster than the material of the anchor portion (<NUM>).