Patent Description:
The present disclosure pertains to medical devices, and methods for manufacturing medical devices. More particularly, the present disclosure pertains to stents including a valve, such as an anti-reflux valve, and methods for manufacturing and using such stents.

The lower esophageal sphincter is a muscle located between the esophagus and the stomach. The sphincter normally functions as a one-way valve, allowing material (e.g., food) that travels downward through the esophagus to enter the stomach while preventing the backflow (reflux) of hydrochloric acid and other gastric contents into the esophagus. However, in some cases the lower esophageal sphincter does not close adequately, and therefore, permits stomach acid to reflux into the esophagus, causing heartburn. A weak or inoperable lower esophageal sphincter is a major cause of gastroesophageal reflux disease (GERD).

Therefore, a variety of intracorporeal medical devices have been developed to treat gastroesophageal disease caused by a malfunctioning lower esophageal sphincter. For example, elongated stents incorporating one-way valves have been developed to allow material (e.g., food) to travel through the esophagus and enter the stomach while also preventing stomach acid to reflux into the esophagus. However, there is an ongoing need to provide alternative configurations of and/or methods of forming stents including a one-way valve to treat gastroesophageal disease, as well as other medical conditions.

<CIT> discloses a luminal endo-prosthesis, especially for expanding duct in human or animal body has expandable covering of fibrous material which permits normal cell invasion, e.g. urethane polycarbonate.

The invention relates to a method for constructing an inner layer within a stent as defined in claim <NUM>. Further embodiments of the invention are defined in the dependent claims.

This disclosure provides design, material, manufacturing method, and use alternatives for medical devices. An example medical device includes a tubular scaffold. The scaffold includes a longitudinal axis, an inner surface and an outer surface. The medical device also includes a flexible valve extending radially inward from the inner surface of the scaffold. The valve includes an annular chamber extending circumferentially around the inner surface of the scaffold and is configured to shift from a closed configuration to an open configuration.

Alternatively or additionally to any of the embodiments above, wherein the valve includes a first end and a second end, the first end spaced along the longitudinal axis from the second end, and wherein the chamber is positioned between the first end and the second end.

Alternatively or additionally to any of the embodiments above, wherein the valve narrows from the first end to the second end.

Alternatively or additionally to any of the embodiments above, wherein the valve further includes a first wall thickness adjacent the first end and a second wall thickness adjacent the second end, and wherein second wall thickness is thicker than the first wall thickness.

Alternatively or additionally to any of the embodiments above, further comprising an inner layer disposed along the inner surface of the scaffold, and wherein the valve is formed from at least a portion of the inner layer.

Alternatively or additionally to any of the embodiments above, further comprising an outer layer disposed along the outer surface of the scaffold, and wherein the annular chamber is defined between the inner layer and the outer layer.

Alternatively or additionally to any of the embodiments above, further comprising an inner layer disposed along the inner surface of the scaffold and an outer layer disposed along the outer surface of the scaffold, wherein the inner layer is circumferentially attached at a first location and a second location, wherein the outer layer extends at least between the first location and the second location, and wherein the annular chamber is defined between the inner layer and outer layer.

Alternatively or additionally to any of the embodiments above, wherein the.

medical device includes at least one aperture extending through the outer layer, the inner layer or both the inner and outer layers.

Alternatively or additionally to any of the embodiments above, wherein the chamber is substantially air-filled.

Alternatively or additionally to any of the embodiments above, wherein the chamber is filled with a material selected from the group comprising liquids, gels, foams and polymers.

Alternatively or additionally to any of the embodiments above, wherein at least a portion of the valve includes a surface texture configured to prohibit material from moving through the valve in a retrograde direction.

Alternatively or additionally to any of the embodiments above, wherein at least a portion of the valve includes a coating comprising one or more acid neutralizers.

Alternatively or additionally to any of the embodiments above, wherein the medical device includes a second valve.

Alternatively or additionally to any of the embodiments above, further comprising a coating applied to the valve, wherein the coating is configured to minimize the surface friction of the valve.

Alternatively or additionally to any of the embodiments above, wherein the coating is a silicone coating.

An esophageal stent includes an expandable tubular scaffold. The scaffold includes a longitudinal axis and an inner surface. The stent also includes a valve positioned on the inner surface of the scaffold, the valve including a first end and a second end. The valve is configured to funnel material along the longitudinal axis and to radially expand from a closed configuration to an open configuration.

Alternatively or additionally to any of the embodiments above, wherein the valve includes a widened portion adjacent the first end of the valve and a closed portion adjacent the second end of the valve.

Alternatively or additionally to any of the embodiments above, wherein the valve narrows from the widened portion to the closed portion.

Alternatively or additionally to any of the embodiments above, wherein the valve further defines an annular chamber extending circumferentially around the inner surface of the scaffold.

Alternatively or additionally to any of the embodiments above, wherein the chamber is filled with a material selected from the group comprising liquids, gels and polymers.

Alternatively or additionally to any of the embodiments above, further comprising an inner layer extending from a first end of the stent to a second end of the stent, and wherein the valve is formed from at least a portion of the inner layer.

An example esophageal stent for treating acid reflux includes an expandable tubular member. The tubular member includes a longitudinal axis and an inner surface. The stent also includes a valve positioned on the inner surface of the scaffold. The valve includes an annular chamber extending circumferentially around the inner surface of the tubular member. The valve is configured to funnel material along the longitudinal axis and to permit material to pass through the valve in a first direction and to prevent material from passing through the valve a second direction, wherein the first direction is opposite the second direction.

On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.

The drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the disclosure.

Gastroesophageal reflux disease (GERD) is a medical condition whereby stomach acids enter the lower portion of the esophagus because the lower esophageal sphincter (positioned at the entrance of the stomach) fails to close properly. In some instances, the lower esophageal sphincter's inability to close is due to disease or general atrophy. When left open, the sphincter may permit reflux of stomach acids into the esophagus, causing severe heartburn and potentially contributing to the onset of other diseases.

One method of treating GERD is to place an anti-reflux stent into the entrance of the stomach. An anti-reflux stent may include an expandable valve which allows food and liquid to enter the stomach but prevents liquids from passing back through the valve. In general, there is an ongoing need for an anti-reflux stent to provide a smooth lumen opening into the stomach while preventing stomach acids from passing back through the valve and into the esophagus.

<FIG> shows an example stent <NUM>. Stent <NUM> may include one or more stent strut members <NUM>. Stent strut members <NUM> may extend longitudinally along stent <NUM>. While <FIG> shows stent strut members <NUM> extending along the entire length of stent <NUM>, in other examples, the stent strut members <NUM> may extend only along a part of stent <NUM>.

Additionally, <FIG> shows example stent <NUM> including one or more flared end portions <NUM> proximate the first and second ends of the stent <NUM>. In some instances, flared portion <NUM> may be defined as an increase in the outer diameter, the inner diameter or both the inner and outer diameter along one or both of the end portions <NUM> of stent <NUM>.

In some instances, stent <NUM> may be a self-expanding stent or stent <NUM> may be a balloon expandable stent. Self-expanding stent examples may include stents having one or more struts <NUM> combined to form a rigid and/or semi-rigid stent structure. For example, stent struts <NUM> may be wires or filaments braided, intertwined, interwoven, weaved, knitted or the like to form the stent structure. Alternatively, stent <NUM> may be a monolithic structure formed from a cylindrical tubular member, such as a single, cylindrical tubular laser-cut Nitinol tubular member, in which the remaining portions of the tubular member form the stent struts <NUM>. Openings or interstices through the wall of the stent <NUM> may be defined between adjacent stent struts <NUM>.

Stent <NUM> in examples disclosed herein may be constructed from a variety of materials. For example, stent <NUM> (e.g., self-expanding or balloon expandable) may be constructed from a metal (e.g., Nitinol). In other instances, stent <NUM> may be constructed from a polymeric material (e.g., PET). In yet other instances, stent <NUM> may be constructed from a combination of metallic and polymeric materials. Additionally, stent <NUM> may include a bioabsorbable and/or biodegradable material.

In some instances, example stent <NUM> may include one or more layers positioned on and/or adjacent to the outer surface of stent <NUM>. For example, <FIG> shows example stent <NUM> including an outer layer <NUM> disposed along the outer surface of stent <NUM>. In some instances, outer layer <NUM> may be an elastomeric or non-elastomeric material. For example, outer layer <NUM> may be a polymeric material, such as silicone, polyurethane, or the like. Further, the outer layer <NUM> may span the spaces (e.g., openings, cells, interstices) in the wall of stent <NUM>. For example, <FIG> shows outer layer <NUM> extending inwardly from the outer surface of stent <NUM> such that the outer layer <NUM> spans one or more of spaces (e.g., openings, cells, interstices) between struts <NUM> in the wall of stent <NUM>.

Additionally, example stent <NUM> may include one or more layers positioned on and/or adjacent to the inner surface of stent <NUM>. <FIG> shows example stent <NUM> including an inner layer <NUM> disposed along the inner surface of stent <NUM>. In some instances, inner layer <NUM> may be an elastomeric or non-elastomeric material. For example, inner layer <NUM> may be a polymeric material, such as silicone, polyurethane, or the like. Further, the inner layer <NUM> may span the spaces (e.g., openings, cells, interstices) in the wall of stent <NUM>. For example, <FIG> shows inner layer <NUM> extending outwardly from the inner surface of stent <NUM> such that the inner layer <NUM> spans one or more of spaces (e.g., openings, cells, interstices) between struts <NUM> in the wall of stent <NUM>.

It can be appreciated that as inner layer <NUM> and outer layer <NUM> extend outwardly and inwardly, respectively, they may touch and/or form an interface region within the spaces (e.g., openings, cells, interstices) in the wall of stent <NUM>. For example, the detailed view of <FIG> shows that both the inner and outer layers <NUM>/<NUM> may extend into the openings defined between adjacent stent struts <NUM> and form an interface region. Further, the inner and outer layers <NUM>/<NUM> may additionally extend between adjacent struts <NUM>, thereby filling any space between adjacent strut members <NUM>.

As shown in <FIG>, stent <NUM> may have a first end <NUM> and a second end <NUM>. When positioned in a body lumen (e.g., esophagus) first end <NUM> may be defined as the end of stent <NUM> closest to a patient's mouth and second end <NUM> may be defined as the end of stent <NUM> closest to a patient's stomach.

As shown in <FIG>, inner layer <NUM> and outer layer <NUM> may extend along the length of stent <NUM> from first end <NUM> to second end <NUM>. In other words, in some instances inner layer <NUM> and outer layer <NUM> may be defined as continuous layers that extend from first end <NUM> to second end <NUM> of stent <NUM>. However, in other instances inner layer <NUM> and/or outer layer <NUM> may extend less than the entire length of stent <NUM>, if desired.

Additionally, <FIG> shows valve member <NUM> positioned within the lumen of stent <NUM>. As will be discussed in greater detail below, valve <NUM> may be defined as a portion of inner layer <NUM>. In other words, valve <NUM> may be a unitary structure formed in conjunction with inner layer <NUM>. For example, <FIG> illustrates that valve <NUM> may be an inwardly extending portion of inner layer <NUM>. In other words, valve <NUM> may be defined as a unitary portion of inner later <NUM> that extends radially inward from an inner surface of stent <NUM> toward the central longitudinal axis <NUM> of stent <NUM>.

Further, in some examples, valve <NUM> may be defined as a portion of inner layer <NUM> that extends circumferentially within the lumen of stent member <NUM>. In other words, it can be appreciated that valve <NUM> may be defined as an annular member that extends continuously around the lumen of stent member <NUM>. Further, valve <NUM> may be defined as an uninterrupted extension of inner layer <NUM> projecting toward central longitudinal axis <NUM>.

As will be discussed in further detail below, <FIG> illustrates that valve <NUM> may include a conical wall and generally be shaped to taper longitudinally from the portion of valve <NUM> closest to first end <NUM> to the portion of valve <NUM> closest to second end <NUM>. For example, the wall of valve <NUM> illustrated in <FIG> may bear some resemblance to a cone-shaped funnel tapering from a wide portion nearest a patient's mouth to a narrow portion nearest a patient's stomach. Further, as illustrated in <FIG>, valve <NUM> may taper inwardly toward central longitudinal axis <NUM> and close (e.g., contact, seal, etc.) onto itself such that it stops flow of material (e.g., stomach acid) from flowing through the lumen of stent <NUM>. As discussed above, it may be desirable for valve <NUM> to prevent stomach acids from flowing from a patient's stomach toward the patient's mouth. <FIG> shows valve <NUM> in a closed portion <NUM>.

However, in some instances it may be desirable for valve <NUM> to expand radially outward to permit nutritional material to pass through the lumen of stent <NUM>. For example, in some examples it is desirable for valve <NUM> to radially expand to permit food to pass from a patient's mouth, through the valve <NUM>, to the stomach.

<FIG> and <FIG> illustrate valve <NUM> expanding radially outward to allow nutritional material (e.g., food) to pass through the lumen of stent <NUM>. As shown by the arrow in <FIG>, and, in general, nutritional material <NUM> may flow through stent <NUM> from a first end <NUM> (e.g., the end closest to a patient's mouth) to a second end <NUM> (e.g., the end closest to a patient's stomach). <FIG> illustrates that valve <NUM> may permit the material <NUM> to pass through the lumen of the stent <NUM> by expanding radially outward as the material <NUM> passes through the valve <NUM>. As shown in <FIG>, in some instances, the valve <NUM> may conform to the shape of material <NUM> as it passes through the valve <NUM>.

<FIG> illustrates an example stent <NUM> including valve member <NUM>. As described above, stent <NUM> may include an outer layer <NUM> and inner layer <NUM>. Further, valve <NUM> may be defined by inner layer <NUM>. For example, <FIG> illustrates that inner layer <NUM> may include a thickness depicted as "X. " It can be appreciated that thickness "X" may be defined as depth to which inner layer <NUM> extends radially inward from the inner surface of stent member <NUM>. In some examples, the inner layer <NUM> may be formed from a silicone material.

<FIG> is an enlarged view of the valve <NUM> within the lumen of the stent <NUM>. As shown in <FIG>, the inner layer <NUM> may separate from the inner surface of stent member <NUM> at two or more locations. For example, <FIG> shows a first detachment point <NUM> and a second detachment point <NUM>. It is noted that detachment points <NUM>/<NUM> are circumferential lines extending around the circumference of stent <NUM> where the inner layer <NUM> moves away from the inner surface of the wall of the stent <NUM> as the inner layer <NUM> moves radially inward toward the longitudinal axis <NUM> to form valve <NUM>. Detachment points <NUM>/<NUM> may be defined as locations at which the outer surface of the inner layer <NUM> separates from the inner surface of stent member <NUM>. It can be appreciated that this location may also be defined as the location at which inner layer <NUM> defines a wall having a "wall thickness" defining valve <NUM>.

<FIG> shows that in some instances the wall thickness of valve <NUM> may be substantially equal to the thickness "X" of inner layer <NUM>. In other words, inner layer <NUM> may maintain a substantially uniform wall thickness along the length of stent member <NUM> (including the wall thickness of valve <NUM>). However, as will be discussed in more detail below, in other embodiments the thickness of inner layer <NUM>, outer layer <NUM> and/or the wall thickness defining valve <NUM> may change along any portion of stent member <NUM>. For example, some portions of inner layer <NUM>, outer layer <NUM> and/or the wall thickness defining valve <NUM> may be thinner or thicker than other portions along stent member <NUM>.

As discussed above, inner layer <NUM> may separate from the inner surface of stent member <NUM> at first and second detachment points <NUM>/<NUM> and be located radially inward and unattached to the inner surface of stent <NUM> between first and second detachment points <NUM>/<NUM>. Further, <FIG> illustrates that the separation of inner layer <NUM> from the inner surface of stent member <NUM> defines a valve <NUM> having a wall thickness "X. " Further yet, <FIG> illustrates a "chamber" <NUM> (e.g., sac, cavity, void, pocket, enclosure, etc.) which may be defined as the space between the valve wall and stent member <NUM> (which may include outer layer <NUM>) between detachment points <NUM>/<NUM>. Chamber <NUM> may be positioned between detachment points <NUM>/<NUM>. In <FIG>, the chamber <NUM> is depicted with a hash-mark pattern for reference. Thus, chamber <NUM> may be defined as a space between the wall of the stent <NUM> (including outer layer <NUM>) and the wall of the valve <NUM> (formed by the inner layer <NUM>) between the circumferential detachment points <NUM>/<NUM>.

Similarly to the above discussion regarding the wall of valve <NUM>, chamber <NUM> may be defined as extending circumferentially within the lumen of stent member <NUM>. In other words, it can be appreciated that chamber <NUM> may be defined as an annular cavity that extends continuously around the lumen of stent member <NUM> radially inward of the stent wall. Further, it can be appreciated the shape of chamber <NUM> is directly related to the shape of the wall of valve <NUM>. In other words, in some instances the shape of valve <NUM> may define the shape of chamber <NUM>.

In some instances, chamber <NUM> may be filled with variety of materials. For example, chamber <NUM> may be filled with a fluid (e.g., a gas, air, liquid, gel or any other similar material). In some instances, chamber <NUM> may be filled with saline, gel or air. In other instances, chamber <NUM> may be filled with a foam material, such as an open-cell foam or a closed-cell foam, which may be readily compressible and recoverable to its original shape. As described above, in some instances it may be desirable for valve <NUM> to expand radially outward (e.g., as food passes through the valve), and therefore, it may be desirable to fill chamber <NUM> with a material that is compressible, displaceable and/or able to move in response to a variety of forces placed thereon.

In other instances chamber <NUM> may only contain air or another type of gas. Similar to that described above, a gas-filled chamber <NUM> may be able to expand radially outward (e.g., as food passes through the valve), and therefore, it may be desirable to fill chamber <NUM> with a gas at a pressure that allows the valve <NUM> to move in response to a variety of forces placed thereon.

Similarly to the example shown in <FIG>, the valve <NUM> illustrated in <FIG> may bear some resemblance to a cone-shaped funnel. For example, the radially inward surface of the wall of valve <NUM> may taper radially inward from detachment point <NUM> to closure point <NUM>. Additionally, <FIG> shows valve <NUM> including a tapered wall portion <NUM> extending from detachment point <NUM> toward central longitudinal axis <NUM>. Further, valve <NUM> may include a wide portion (depicted in <FIG> as dimension "Y") tapering to a narrower portion (depicted in <FIG> as dimension "Z"). As shown in <FIG>, the wide portion of valve <NUM> may be positioned adjacent to first detachment point <NUM>, while the narrower portion may be positioned closer to closure point <NUM>. Further, as described above with respect to <FIG>, the continuous, circumferential (e.g., annular) shape of valve <NUM> may define a funnel-shaped portion <NUM>.

Additionally, valve <NUM> may include a rounded portion <NUM> and a downward-facing portion <NUM>. For simplicity purposes, the term "downward-facing" is used herein to generally describe portions of valve <NUM> which face toward the stomach distal of closure point <NUM>. As illustrated in <FIG>, rounded portion <NUM> is positioned between tapered portion <NUM> and downward-facing portion <NUM>. In other words, in some examples, valve <NUM> may be defined as including tapered portion <NUM>, rounded portion <NUM>, and downward-facing portion <NUM> (which terminates at second detachment point <NUM>). In some instances, tapered portion <NUM> begins to taper at a point adjacent to first detachment point <NUM>. Downward-facing portion <NUM> may extend from rounded portion <NUM> to second detachment point <NUM>. In some examples, closure point <NUM> may be located along a portion of rounded portion <NUM>. Closure point <NUM> may be located between first and second detachment points <NUM>/<NUM> proximate central longitudinal axis <NUM>. For example, closure point <NUM> may be at central longitudinal axis <NUM>.

Additionally, <FIG> shows outer layer <NUM> extending along stent <NUM> for the entire length of valve <NUM>. In other words, stent <NUM> may include outer layer <NUM> extending from at least detachment point <NUM> to detachment point <NUM>. However, in some examples, outer layer <NUM> may extend the entire length of stent <NUM>, while in other instances outer layer <NUM> may not extend the entire length of stent <NUM>. In some examples, the outer layer <NUM> may be configured to prevent cellular ingrowth. For instance, in some examples outer layer <NUM> may include a polymeric material, such as polyurethane or silicone (e.g., high durometer silicone) to resist cellular ingrowth. The radially outward extent of chamber <NUM> may be bounded by outer layer <NUM>, whereas the radially inward extent of chamber <NUM> may be bounded by inner layer <NUM>.

<FIG> shows a cross-sectional view along line <NUM>-<NUM> of <FIG>. In particular, line <NUM>-<NUM> of <FIG> intersects closure point <NUM> described above. Therefore, as shown in <FIG>, closure point <NUM> is positioned in the center of the lumen of stent <NUM>. Further, <FIG> shows outer layer <NUM>, stent <NUM>, chamber <NUM> and inner layer <NUM>. Additionally, <FIG> illustrates that chamber <NUM> and inner layer <NUM> extend circumferentially around the central longitudinal axis <NUM> (which coincides with closure point <NUM> in <FIG>). As described above, <FIG> shows that chamber <NUM> and inner layer <NUM> (defining the wall of valve <NUM>), extend continuously around the central longitudinal axis <NUM>. As noted above, the radially outward extent of chamber <NUM> may be bounded by outer layer <NUM> and the radially inward extent of chamber <NUM> may be bounded by inner layer <NUM>.

<FIG> shows an example stent <NUM> including features and/or elements similar to those described above. For example, <FIG> shows a valve <NUM> including stent <NUM>, outer layer <NUM>, and inner layer <NUM> defining tapered conical portion <NUM>, rounded portion <NUM> and downward-facing portion <NUM>. Additionally, valve <NUM> defines chamber <NUM> extending between first detachment point <NUM> and second detachment point <NUM> and bounded by the inner layer <NUM> and the outer layer <NUM>. Namely, the radially outward extent of chamber <NUM> may be bounded by outer layer <NUM> and the radially inward extent of chamber <NUM> may be bounded by inner layer <NUM>. However, the configuration of valve <NUM> in <FIG> does not include a closure point. Rather, <FIG> shows that in some instances while tapered portion <NUM> of valve <NUM> tapers radially inward towards the central longitudinal axis <NUM>, it does not form a closure point <NUM>. Rather, <FIG> shows that in some examples valve <NUM> includes a valve opening <NUM> located at the central longitudinal axis <NUM>.

<FIG> shows a cross-sectional view of the example stent <NUM> and valve <NUM> depicted in <FIG>. The cross-section shown in <FIG> is taken along line <NUM>-<NUM> of <FIG>. Line <NUM>-<NUM> of <FIG> transects the valve opening <NUM> described above. As noted above, the radially outward extent of chamber <NUM> may be bounded by outer layer <NUM> and the radially inward extent of chamber <NUM> may be bounded by inner layer <NUM>. As shown in <FIG> (and contrasted with the example valve shown in <FIG>), valve opening <NUM> may be defined as an aperture and/or opening centered about the central longitudinal axis <NUM> of the lumen of stent <NUM>. However, while the figures described herein depict example valves and related elements centered about the central longitudinal axis, it is contemplated that any of the examples described herein may be designed such that the structural elements defining any portion of stent <NUM> and/or valve <NUM> may be off-center. In other words, valve <NUM> may be asymmetrical about the central longitudinal axis <NUM> in one or more examples described herein.

<FIG> illustrate several of a variety of possible shapes for an example valve <NUM>. It is noted that conical wall portion <NUM> may taper distally to central longitudinal axis <NUM> at any desired angle. Additionally, downward-facing portion <NUM> may extend toward central longitudinal axis <NUM> from the tubular wall of stent <NUM> at any desired angle. In some examples, such as those shown in <FIG>, the trajectory of downward-facing portion <NUM> of valve <NUM> may be characterized by defining an angle θ extending between a line drawn tangent to downward-facing portion <NUM> and stent <NUM>.

For example, <FIG> shows angle θ to be an acute angle taken from the surface defined by stent member <NUM> which is below (distal of) detachment point <NUM>. In other words, angle θ shown in <FIG> extends less than <NUM>° from the surface defined by stent member <NUM> which is below (distal of) detachment point <NUM>. Thus, downward-facing portion <NUM> may extend distally from detachment point <NUM> as downward-facing portion <NUM> extends toward central longitudinal axis <NUM>. Further, it can be seen from <FIG> that rounded portion <NUM> of valve <NUM> may extend below (distal of) the detachment point <NUM>.

<FIG> shows angle θ to be an angle generally perpendicular to the surface defined by stent member <NUM> which is below (distal of) detachment point <NUM>. In other words, angle θ shown in <FIG> extends approximately <NUM>° from the surface defined by stent member <NUM> which is below detachment point <NUM>. Thus, downward-facing portion <NUM> may extend perpendicular to central longitudinal axis <NUM> from detachment point <NUM> as downward-facing portion <NUM> extends toward central longitudinal axis <NUM>. Further, it can be seen from <FIG> that rounded portion <NUM> of valve <NUM> may not extend below the detachment point <NUM>.

<FIG> shows angle θ to be an obtuse angle taken from the surface defined by stent member <NUM> which is below (distal of) detachment point <NUM>. In other words, angle θ shown in <FIG> extends greater than <NUM>° from the surface defined by stent member <NUM> which is below (distal of) detachment point <NUM>. Thus, downward-facing portion <NUM> may extend proximally from detachment point <NUM> as downward-facing portion <NUM> extends toward central longitudinal axis <NUM>. Further, it can be seen from <FIG> that rounded portion <NUM> of valve <NUM> may extend above (proximal of) the detachment point <NUM>.

In some examples, stent <NUM> may include one or more surface textures, patterns, micro-patterns, micro-texture, roughened-surfaces, ridges or the like designed and/or configured to prevent or impede material from moving through valve <NUM> in an retrograde direction (i.e., toward the mouth of the patient). Specifically, it may be desirable to include a surface texture along a portion of valve <NUM> which prevents material (e.g., stomach acids) from migrating from a patient's stomach, through an example valve, and to a patient's esophagus proximal of the valve <NUM> and stent <NUM>.

<FIG> shows example stent <NUM> including example valve <NUM>. Further, <FIG> shows a surface texture <NUM> positioned along the downward-facing portion <NUM> of valve <NUM>. It can be appreciated that surface texture <NUM> may be positioned such that it is the first portion of valve <NUM> which may be contacted by material migrating from the stomach. It can be further appreciated that the surface texture <NUM> may include elements and/or shapes configured to alter the flow of material migrating upward from the stomach. For example, surface texture <NUM> may include points, tips, indents, cavities, holes, hooks, protrusions, etc., or any combinations thereof. Surface texture <NUM> may be configured to prevent retrograde movement of stomach acid, etc. from moving proximally along the surface of downward-facing portion <NUM> of valve <NUM>. Further, in some examples surface texture <NUM> may be located on other portions of valve <NUM> and/or stent <NUM>. For example, surface texture <NUM> may be positioned on rounded portion <NUM> and/or tapered portion <NUM>. In some instances, the surface texture may include a textured silicone.

Further, in some instances it may be desirable to include a coating on one or more portions of stent <NUM> (including example valve <NUM>). The coating may be configured to aid the passage of material through valve <NUM>. For example, the coating may reduce the surface friction of one or more portions of valve <NUM>. In other words, the coating may make the surface of valve <NUM> that contacts material more slippery. In some instances, the coating may include silicone.

In other examples, either the surface texture (described above) or the surface coating (described above) may include hydrophilic elements (e.g., hydrophilic surface texture) or may also include micro-beads (e.g., micro-bead surface texture). In some examples, the micro-beads may be filled with acid neutralizers.

As discussed above, inner layer <NUM> may define valve <NUM>. Further, inner layer <NUM> may define a wall thickness of one or more portions of valve <NUM>. As stated above, the wall thickness defined by inner layer <NUM> may remain substantially uniform along stent <NUM> (including the portion of inner layer <NUM> defining valve <NUM>). However, in some instances the thickness of inner layer <NUM> may vary along stent <NUM>. For example, in some instances one portion of the wall thickness defining valve <NUM> may be different than another portion of the wall thickness defining valve <NUM>.

<FIG> shows a first portion of valve <NUM> including a wall thickness depicted as "X. " Further, <FIG> shows a second portion of valve <NUM> including a wall thickness depicted as "W. " In some instances, wall thickness "W" is thicker than wall thickness "X. " Additionally, in some instances it may be desirable to include a thicker portion of valve <NUM> along downward-facing portion <NUM> of valve <NUM>. However, this is not intended to be limiting. As such, gravity pulling down on thicker portion of valve along downward-facing portion <NUM> of valve <NUM> may tend to close valve <NUM>. It is contemplated in some examples that any portion of valve <NUM> may include a wall thickness that is thicker (or different) from another portion.

In some examples, stent <NUM> may include anti-migration elements. Anti-migration elements may include openings, flares, fins, micro-patterns, controlled ingrowth features, quills, or the like. Anti-migration features may be beneficial in controlling the amount stent <NUM> moves during and/or after deployment in the body lumen.

In some instances, one or more portions of stent <NUM> may include openings configured to allow cellular in-growth into the openings or interstices between stent struts. Cellular ingrowth may prevent stent migration. <FIG> shows stent <NUM> including openings <NUM> in outer layer <NUM> configured to permit tissue in-growth therein. <FIG> shows four example openings <NUM> extending through outer layer <NUM>. It is also contemplated that stent <NUM> may include openings in inner layer <NUM> coinciding with openings in outer layer <NUM>. However, it is contemplated that more or less than four openings may be included on outer layer <NUM> and/or inner layer <NUM>. Additionally, it is contemplated that openings <NUM> may extend and be aligned through outer layer <NUM>, openings or interstices of the wall of stent <NUM> and inner layer <NUM>.

In some examples, the inner layer <NUM> and/or outer layer <NUM> may be applied by spraying, dipping, spinning or attaching a polymer material on the inner and/or outer surface of stent <NUM>. In some examples, the covering may cover the stent filaments <NUM>. Further, as described above, the inner layer <NUM> and/or outer layer <NUM> may extend between one or more openings, cells or interstices extending between adjacent stent filaments <NUM>.

<FIG> shows an example method for constructing the inner layer <NUM> within stent <NUM>. As shown in <FIG>, a mandrel <NUM> may be inserted into lumen of stent <NUM>. It can be appreciated that mandrel <NUM> may be a variety of shapes and/or configurations. For example, mandrel <NUM> may be a generally cylindrical member, which in some instances may include first and/or second flared end regions configured to form flared end regions of the stent <NUM>. Further, it can be appreciated that the shape of mandrel <NUM> may define the shape of inner layer <NUM>. For example, <FIG> shows spraying element <NUM> applying a spray <NUM> to stent <NUM> and mandrel <NUM> extending within lumen of stent <NUM>. It can be appreciated that spray <NUM> may pass through the cells of stent member <NUM>, forming a layer of material on the inner surface of stent <NUM> and/or on mandrel <NUM>. The layer of material applied to inner surface of stent <NUM> and/or mandrel <NUM> may correspond to inner layer <NUM> described in the examples above. Further, as shown in <FIG>, spraying element <NUM> may translate the full length of stent <NUM> while rotating stent <NUM> and mandrel <NUM> together, depositing material corresponding to inner layer <NUM> accordingly.

Additionally, <FIG> shows mandrel <NUM> including one or more recessed portions <NUM>. Recessed portion <NUM> may extend circumferentially around the entire circumference of mandrel <NUM>. Recessed portions <NUM> may facilitate formation of one or more portions of inner layer <NUM> that extend radially inward from the inner surface of stent member <NUM>. Accordingly, the shape/contour of inner layer <NUM> forming the valve <NUM> may be determined by the profile of the surface of recessed portion <NUM>. <FIG> shows that in some instances, the outer surface of mandrel <NUM> will be positioned and/or aligned substantially "flush" with the inner surface of stent <NUM>. Depositing layer <NUM> along portions of mandrel <NUM> which are substantially flush with the interior surface of stent <NUM> may cause inner layer <NUM> to adhere to and/or form an integral interface with the inner surface of stent member <NUM>.

However, applying spray <NUM> along portions of mandrel <NUM> which are not substantially flush with the interior surface of stent <NUM> (e.g., recessed portions <NUM>) may result in spray <NUM> passing through the cell openings of stent <NUM> and being deposited along the surface of recessed portions <NUM> of mandrel <NUM>. It can be appreciated that the recessed portions <NUM> of mandrel <NUM> may allow space for spray <NUM> to extend radially inward beyond the inner surface of stent <NUM> such that the inner layer <NUM> is not contacting the stent <NUM> throughout recessed portion <NUM>. It can be further appreciated from <FIG> that inner layer <NUM> applied along surface of recessed portions <NUM> may, therefore, form the radially inward extending portions of valve <NUM>.

<FIG> shows stent <NUM> after manufacturing mandrel <NUM> (e.g., mandrel <NUM> described with respect to <FIG>) has been removed. It can be appreciated that valve <NUM> may be formed from a deflectable and/or compressible material which would deform as mandrel <NUM> is removed from stent <NUM>. In other words, after valve <NUM> has been constructed according to the manufacturing method described with respect to <FIG>, mandrel <NUM> may be removed by pulling it longitudinally through the lumen of stent <NUM>. The flexibility of valve <NUM> may permit mandrel <NUM> to be removed accordingly. As shown in <FIG>, stent <NUM> including inner layer <NUM> may be include all the features and/or elements described with respect to <FIG> above.

<FIG> shows an example method for constructing and/or forming the outer layer <NUM> of the stent <NUM> described with respect to <FIG> above. As illustrated in <FIG>, a second manufacturing mandrel <NUM> may be inserted into stent <NUM>. The second mandrel <NUM> may not include a annular recess, thus pushing inner layer <NUM> forming valve <NUM> radially outward. In some examples, mandrel <NUM> may be configured such that it forces the inner layer <NUM> (the construction of which is described with respect to <FIG> and <FIG> above) radially outward and substantially aligns inner layer <NUM> along the inner surface of stent <NUM>. In particular, mandrel <NUM> may force the valve portion <NUM> (which extends radially inward from the inner surface of stent <NUM>) to align with the portion of inner layer <NUM> affixed to the inner surface of stent <NUM>.

Additionally, <FIG> shows spraying element <NUM> applying a spray <NUM> to the outer surface of stent <NUM>. The layer of material applied to the outer surface of stent <NUM> may correspond to outer layer <NUM> described in the examples above. Further, as shown in <FIG>, spraying element <NUM> may translate the full length of stent <NUM> while rotating stent <NUM> and mandrel <NUM> together, depositing material corresponding to outer layer <NUM> accordingly.

In some examples, a portion of inner layer <NUM> may be masked or treated prior to the application of spray <NUM> (corresponding to outer layer <NUM>). For example, in some instances the portion of inner layer <NUM> corresponding to valve <NUM> (i.e., the circumferential portion between first detachment point <NUM> and second detachment point <NUM> may be masked or treated (e.g., a talc applied to portion of inner layer <NUM>) such that it does not adhere to the inner surface of stent <NUM> and/or outer layer <NUM> while the outer layer <NUM> is being deposited along stent <NUM>. However, circumferential portions of outer layer <NUM> proximal of first detachment point <NUM> and distal of second detachment point <NUM> may adhere to inner layer <NUM> and/or stent <NUM>, thus forming a circumferential chamber <NUM> between inner layer <NUM> and outer layer <NUM> spanning the longitudinal distance between the first and second detachment points <NUM>/<NUM>.

In some embodiments, the stent <NUM> may include a plurality of valves. For example, <FIG> shows an example stent <NUM> including two valves <NUM>/<NUM>. It can be appreciated that valves <NUM>/<NUM> may have the same shape or they may have different shapes. Further, valves <NUM>/<NUM> may be positioned along any portion of stent member <NUM>. For example, valves <NUM>/<NUM> may be spaced farther apart than illustrated in <FIG>. Additionally, one or more of valves <NUM>/<NUM> may incorporate any of the features and/or elements of any of the example stents disclosed herein.

In some examples it may be desirable to include one or more therapeutic agents designed to alleviate and/or mitigate discomfort from acid reflux. For example, any of the examples disclosed herein may include a coating including an acid neutralizer intended to neutralize stomach acids in the esophagus. For example, the down-facing portion of the valve may include a coating including an acid neutralizer. Stomach acids escaping from the stomach may be neutralized when they come into contact with the acid neutralizer.

Claim 1:
A method for constructing an inner layer (<NUM>) within a stent (<NUM>), the method comprising:
positioning a mandrel (<NUM>) within a lumen of the stent (<NUM>), the stent (<NUM>) including a plurality of filaments and a plurality of openings extending between stent filaments, the plurality of openings extending through a wall of the stent, and wherein the mandrel (<NUM>) includes a recessed portion (<NUM>);
applying a material on the stent (<NUM>) and through the openings of the stent such that the material is deposited along the recessed portion (<NUM>) of the mandrel (<NUM>) and extends radially inward beyond an inner surface of the stent; and
removing the mandrel (<NUM>).