Patent Description:
In general, the human body includes various lumens, such as a trachea, blood vessels, urinary, biliary, esophageal, or renal tracts, etc. These lumens sometimes become occluded or weakened, or otherwise in need of structural support. For example, the body lumen can be constricted by a tumor, occluded by plaque or a stricture, or weakened by an aneurysm. Endoprostheses or stents have been developed that may be implanted in a passageway or lumen in the body. In general, such endoprostheses are tubular members with a circular cross-section, examples of which include stents, stent grafts, covered stents, etc..

Current braided or knitted self-expanding endoprostheses may express a large degree of longitudinal flexibility due to design and device length. This may be advantageous for the purpose of device delivery, especially in more tortuous anatomical regions and for reduction in lumen straightening post-delivery, which is typically seen as being less traumatic on target lumens. In some cases, a bare endoprosthesis may include an additional coating where benign strictures are to be treated, stent removal may be a requirement, and/or where the coating is used to isolate a treated lumen from nutritional impaction (e.g., post bariatric surgery leak treatment, fistula treatment, etc.). Braided and knitted stents are sometimes used in the tracheobronchial lumens to help keep the airway open.

An issue with braided and knitted stents in the tracheobronchial lumens is the possibility of fracture and/or failure as a result of fatigue. Forced inspiration/expiration and/or coughing may lead to large deformation of the body lumen and corresponding deformation of a stent disposed in the body lumen. Due to the anatomy of the trachea and bronchi, the deformations of these lumens may be radially non-uniform and result in concentrated areas of high stress on the implanted stent. In the trachea, during forced inspiration/expiration and/or coughing the cartilage rings compress radially and the smooth muscle tissue indents. Sharp fold lines are formed resulting in a crescent shape. The implanted stent will deform in a similar manner causing areas of high stress and eventually possible stent fractures along the sharp fold lines. The bronchi undergo a more complete radial compression because the smooth muscle tissue and cartilage rings are more evenly distributed around the lumen, however there can still be stress concentrations in areas around the stent.

In isolation, these movements may be generally unharmful to the stent. However, repeated exposure to significant amounts of deformation may cause fatigue and/or fractures in the filament(s) that form the stent over time. In some cases, the fatigue and/or fracture may further cause a loss of covering integrity. There is an ongoing need to provide alternative endoprostheses or stents as well as alternative methods for manufacturing and using endoprostheses or stents.

Known stents are, for example, disclosed in <CIT>, <CIT> and <CIT>. In particular, <CIT> discloses an endoprosthesis comprising a tubular scaffold with a polymeric covering, wherein the tubular scaffold does not have any cutout.

All embodiments not falling under the scope of the independent claims do not form part of the invention. Devices and methods mentioned in the following, which do not form part of the invention are show for illustrative purposes only.

A first aspect of the invention is directed to an endoprosthesis configured to shift between a collapsed configuration and an expanded configuration comprises a tubular scaffold formed from a single filament knitted about a central longitudinal axis and defining a length from a proximal end to a distal end, the tubular scaffold including a plurality of rows of loops and a plurality of rows of rungs arranged around the central longitudinal axis in an alternating fashion; and a polymeric covering extending along the tubular scaffold. Each row of loops extends longitudinally along the tubular scaffold between the proximal end and the distal end. Each row of rungs extends longitudinally along the tubular scaffold between the proximal end and the distal end. The tubular scaffold includes a first cutout region extending along a majority of the length of the tubular scaffold and defining a first proximal end oriented toward the proximal end of the tubular scaffold and a first distal end oriented toward the distal end of the tubular scaffold, and a second cutout region extending along a majority of the length of the tubular scaffold and defining a second proximal end oriented toward the proximal end of the tubular scaffold and a second distal end oriented toward the distal end of the tubular scaffold. The polymeric covering is uninterrupted along the first cutout region and the second cutout region.

According to a preferred embodiment of the first aspect of the invention, the first cutout region is formed by removing a medial portion of a first row of loops and medial portions of rows of rungs immediately adjacent to the first row of loops along the majority of the length of the tubular scaffold.

According to a preferred embodiment of the first aspect of the invention, forming the first cutout region causes the single filament to be discontinuous within the first cutout region.

According to a preferred embodiment of the first aspect of the invention, the discontinuous single filament comprises a first plurality of terminal ends extending along the first cutout region.

According to a preferred embodiment of the first aspect of the invention, the second cutout region is formed by removing a medial portion of a second row of loops and medial portions of rows of rungs immediately adjacent to the second row of loops along the majority of the length of the tubular scaffold.

According to a preferred embodiment of the first aspect of the invention, forming the second cutout region causes the single filament to be discontinuous within the second cutout region.

According to a preferred embodiment of the first aspect of the invention, the discontinuous single filament comprises a second plurality of terminal ends extending along the second cutout region.

According to a preferred embodiment of the first aspect of the invention, the second cutout region is circumferentially spaced apart from the first cutout region.

According to a preferred embodiment of the first aspect of the invention, the first proximal end and the second proximal end are disposed distal of the proximal end of the tubular scaffold. The first distal end and the second distal end are disposed proximal of the distal end of the tubular scaffold.

According to a preferred embodiment of the first aspect of the invention, the first cutout region extends along at least <NUM>% of the length of the tubular scaffold.

A second aspect of the invention is directed to a method of making an endoprosthesis configured to shift between a collapsed configuration and an expanded configuration comprises: knitting a tubular scaffold from a single filament, the tubular scaffold including a plurality of rows of loops and a plurality of rows of rungs arranged around a central longitudinal axis in an alternating fashion; heat setting the tubular scaffold in the expanded configuration; after the heat setting step, removing a medial portion of a first row of loops and medial portions of rows of rungs immediately adjacent to the first row of loops along a majority of a length of the tubular scaffold to form a first cutout region; and after the removing step, applying a polymeric covering to the tubular scaffold, wherein the polymeric covering is uninterrupted along the first cutout region.

According to a preferred embodiment of the second aspect of the invention, the method may further comprise: after the heat setting step, removing a medial portion of a second row of loops and medial portions of rows of rungs immediately adjacent to the second row of loops along the majority of the length of the tubular scaffold to form a second cutout region.

According to a preferred embodiment of the second aspect of the invention, the second cutout region is circumferentially spaced apart from the first cutout region.

According to a preferred embodiment of the second aspect of the invention, forming the first cutout region causes the single filament to be discontinuous within the first cutout region.

According to a preferred embodiment of the second aspect of the invention, the discontinuous single filament comprises a first plurality of terminal ends extending along the first cutout region. The first plurality of terminal ends is embedded within the polymeric covering.

A configuration not falling under the scope of the claims is directed to an endoprosthesis configured to shift between a collapsed configuration and an expanded configuration may comprise a tubular scaffold formed from a single filament knitted about a central longitudinal axis and defining a length from a proximal end to a distal end, the tubular scaffold including a plurality of rows of loops and a plurality of rows of rungs arranged around the central longitudinal axis in an alternating fashion; and a polymeric covering extending along the tubular scaffold. Each row of loops may extend longitudinally along the tubular scaffold between the proximal end and the distal end. each row of rungs may extend longitudinally along the tubular scaffold between the proximal end and the distal end. A first row of loops of the plurality of rows of loops may be discontinuous along a medial region of the tubular scaffold and rows of rungs on circumferentially opposite sides of the first row of loops may be discontinuous along the medial region of the tubular scaffold. A second row of loops of the plurality of rows of loops circumferentially opposite the first row of loops may be discontinuous along the medial region of the tubular scaffold and rows of rungs on opposite sides of the second row of loops may be discontinuous along the medial region of the tubular scaffold. The polymeric covering may be continuous along the medial region of the tubular scaffold. The polymeric covering may be formed from silicone. The medial region may extend along at least <NUM>% of the length of the tubular scaffold.

According to a preferred embodiment of said configuration, within the medial region the single filament comprises a plurality of discontinuous segments.

According to a preferred embodiment of said configuration, the plurality of discontinuous segments forms a plurality of terminal ends along the medial region, the plurality of terminal ends being embedded within the polymeric covering.

According to a preferred embodiment of said configuration, the endoprosthesis is self-biased toward the expanded configuration.

The above summary of some embodiments, aspects, and/or examples is not intended to describe each disclosed embodiment or every implementation of the present is disclosure.

While aspects of the disclosure are amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit aspects of the invention to the particular embodiments described.

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

For simplicity and clarity purposes, not all elements of the disclosure are necessarily shown in each figure or discussed in detail below.

Still other relative terms, such as "axial", "circumferential", "longitudinal", "lateral", "radial", etc. and/or variants thereof generally refer to direction and/or orientation relative to a central longitudinal axis of the disclosed structure or device.

The term "extent" may be understood to mean a greatest measurement of a stated or identified dimension, unless the extent or dimension in question is preceded by or identified as a "minimum", which may be understood to mean a smallest measurement of the stated or identified dimension. For example, "outer extent" may be understood to mean an outer dimension, "radial extent" may be understood to mean a radial dimension, "longitudinal extent" may be understood to mean a longitudinal dimension, etc. Each instance of an "extent" may be different (e.g., axial, longitudinal, lateral, radial, circumferential, etc.) and will be apparent to the skilled person from the context of the individual usage. Generally, an "extent" may be considered a greatest possible dimension measured according to the intended usage, while a "minimum extent" may be considered a smallest possible dimension measured according to the intended usage. In some instances, an "extent" may generally be measured orthogonally within a plane and/or cross-section, but may be, as will be apparent from the particular context, measured differently - such as, but not limited to, angularly, radially, circumferentially (e.g., along an arc), etc..

The terms "monolithic" and "unitary" shall generally refer to an element or elements made from or consisting of a single structure or base unit/element. A monolithic and/or unitary element shall exclude structure and/or features made by assembling or otherwise joining multiple discrete structures or elements together.

Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it would be within the knowledge of one skilled in the art to implement the particular feature, structure, or characteristic in connection with other embodiments, whether or not explicitly described, unless clearly stated to the contrary.

In some embodiments, alterations of and deviations from previously used numerical nomenclature may be made in the interest of brevity and clarity.

The figures illustrate selected components and/or arrangements of an endoprosthesis or stent. It should be noted that in any given figure, some features of the endoprosthesis or stent may not be shown, or may be shown schematically, for simplicity. Additional details regarding some of the components of the endoprosthesis or stent may be illustrated in other figures in greater detail. For example, a reference to "the filament", "the cell", "the strut", or other features may be equally referred to all instances and quantities beyond one of said feature. As such, it will be understood that the following discussion may apply equally to any and/or all of the components for which there are more than one within the endoprosthesis or stent, unless explicitly stated to the contrary.

In some patients, a stricture may form or develop that may partially or completely block a body lumen such as the trachea, the esophagus, the common bile duct, the pancreatic duct, etc., thus requiring treatment. It will be appreciated that this disclosure may be directed to features that facilitate and/or permit treatment of body lumens.

A prior art knitted stent <NUM> is illustrated in <FIG>. The prior art knitted stent <NUM> has been used to treat body lumens. The prior art knitted stent <NUM> may include a plurality of spines <NUM> and a plurality of rungs <NUM> interposed between adjacent spines of the plurality of spines <NUM>. The prior art knitted stent <NUM> may be formed from one continuous wire. When unconstrained, the prior art knitted stent <NUM> may have a generally circular cross-sectional shape and/or extent. When placed in the anatomy for treatment, the prior art knitted stent <NUM> may be flexible enough to approximate the shape of the body lumen in which it is implanted, as seen in <FIG> for example, which illustrates a cross-section of a portion of a patient's trachea <NUM> with the prior art knitted stent <NUM> implanted therein.

The trachea <NUM> is a passage that enables air to travel between the oral and nasal cavities into the bronchi, in order to reach the lungs during breathing. The trachea <NUM> may include an anterior wall <NUM>, a posterior wall <NUM>, and lateral walls <NUM> extending between the anterior wall <NUM> and the posterior wall <NUM>. The trachea <NUM> may have an elongated D-shaped cross-section with the flat posterior wall <NUM>. When implanted, the prior art knitted stent <NUM> may naturally settle into the lumen <NUM> of the trachea <NUM> with spines (e.g., corner spines <NUM>) of the plurality of spines <NUM> positioned adjacent the flat posterior wall <NUM>.

Several C-shaped bars of the hyaline cartilage <NUM> prevent the trachea <NUM> from collapsing. The posterior wall <NUM> includes a trachealis muscle <NUM> that constricts into the lumen <NUM> of the trachea <NUM> to narrow the airway in order expel air from the trachea <NUM> during a cough, as shown in <FIG>, and the anterior wall <NUM> includes cartilage rings. The trachea <NUM> is oriented anterior to the esophagus <NUM>, with the trachealis muscle <NUM> positioned between the lumen <NUM> of the trachea <NUM> and the esophagus <NUM>.

<FIG> illustrates how during forced inspiration/expiration and/or coughing the lumen <NUM> of the trachea <NUM> is deformed by the trachealis muscle <NUM> constricting into the lumen <NUM>. Sharp fold lines for formed in lateral corners of the lumen <NUM> adjacent the posterior wall <NUM> resulting in a crescent shape. The implanted stent <NUM> will deform in a similar manner causing areas of high stress in the corner spines <NUM> and eventually possible stent fractures along the sharp fold lines and/or the corner spines <NUM>.

<FIG> illustrates a side view of the prior art knitted stent <NUM> subjected to a lateral force LF, as would occur during inspiration/expiration and/or coughing. A portion of the prior art knitted stent <NUM> is deflected inward along the corner spines <NUM>. This portion travels longitudinally along the length of the prior art knitted stent <NUM> as the lateral force LF moves, as would occur during forced inspiration/expiration and/or coughing. As such, the areas of high stress would not be limited to a single portion the knitted stent <NUM> but would instead extend along the length of the knitted stent <NUM>.

In another example, <FIG> illustrates the prior art knitted stent <NUM> bent almost in half (approximately <NUM> degrees), to show kinking that may occur at severe bends in the anatomy due to limited flexibility of the prior art knitted stent <NUM>. The knitted pattern of the stent <NUM> does not allow for stretching over the outside of the bend or compression at the inside of the bend, thus the stent <NUM> forms a kink <NUM> at the bend. As the knitted pattern contains spines that run parallel to the stent (as seen in <FIG>), there is build-up of material at the bend, which causes the stent <NUM> to kink. The kinking tendency shown in <FIG> limits the flexibility and/or the bending capability of the prior art knitted stent <NUM>.

<FIG> illustrates aspects of an endoprosthesis <NUM> designed and configured to address shortcomings of the prior art knitted stent <NUM>. The term "endoprosthesis" may be used interchangeably with the term "stent" herein. For ease of illustration, the endoprosthesis <NUM> is shown in a flat pattern configuration. The endoprosthesis <NUM> comprises a tubular scaffold <NUM> formed from a single filament knitted about a central longitudinal axis A and defining a length from a proximal end <NUM> to a distal end <NUM>.

The endoprosthesis <NUM> and/or the tubular scaffold <NUM> is configured to shift between a collapsed configuration and an expanded configuration. The collapsed configuration may be a configuration in which the endoprosthesis <NUM> is axially elongated and/or radially collapsed or compressed compared to the expanded configuration. The expanded configuration may be a configuration in which the endoprosthesis <NUM> is axially shortened and/or radially expanded compared to the collapsed configuration. In at least some embodiments, the endoprosthesis <NUM> and/or the tubular scaffold <NUM> may be self-expandable. For example, the endoprosthesis <NUM> and/or the tubular scaffold <NUM> may be formed from a shape memory material. In some embodiments, the endoprosthesis <NUM> and/or the tubular scaffold <NUM> may be mechanically expandable. For example, the endoprosthesis <NUM> and/or the tubular scaffold <NUM> may be expandable using an inflatable balloon, using an actuation member, or other suitable means. During delivery to a treatment site, the endoprosthesis <NUM> and/or the tubular scaffold <NUM> may be disposed within a lumen of a delivery sheath in the collapsed configuration. Upon removal from the lumen of the delivery sheath, the endoprosthesis <NUM> and/or the tubular scaffold <NUM> may shift and/or may be shifted from the collapsed configuration to the expanded configuration.

The tubular scaffold <NUM> may include and/or be formed with a plurality of cells. In some embodiments, the tubular scaffold <NUM> may include and/or be formed from the single filament interwoven around the central longitudinal axis of the endoprosthesis <NUM> and/or the tubular scaffold <NUM>. In at least some embodiments, the single filament may form and/or define the plurality of cells. The tubular scaffold <NUM> is knitted from the single filament. In some embodiments, the single filament may be a wire, a thread, a strand, etc. In some embodiments, adjacent portions of the single filament may define openings or interstices through a wall of the tubular scaffold <NUM>. Alternatively, in some embodiments, the tubular scaffold <NUM> 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, in which the remaining (e.g., unremoved) portions of the tubular member form the tubular scaffold <NUM> with openings or interstices defined therebetween.

The tubular scaffold <NUM> may be substantially tubular and/or may include a lumen extending axially therethrough along the central longitudinal axis A of the tubular scaffold <NUM>. In some embodiments, the tubular scaffold <NUM> may have an axial length of about <NUM> millimeters to about <NUM> millimeters, about <NUM> millimeters to about <NUM> millimeters, about <NUM> millimeters to about <NUM> millimeters, about <NUM> millimeters to about <NUM> millimeters, about <NUM> millimeters to about <NUM> millimeters, or another suitable range. In some embodiments, the tubular scaffold <NUM> may have a radial outer dimension or radial extent of about <NUM> millimeters to about <NUM> millimeters, about <NUM> millimeters to about <NUM> millimeters, about <NUM> millimeters to about <NUM> millimeters, about <NUM> millimeters to about <NUM> millimeters, or another suitable range. Other configurations are also contemplated. Some suitable but non-limiting materials for the endoprosthesis <NUM>, the tubular scaffold <NUM>, and/or components or elements thereof, for example metallic materials and/or polymeric materials, are described below.

The tubular scaffold <NUM> includes a plurality of rows of loops <NUM> and a plurality of rows of rungs <NUM> arranged around the central longitudinal axis A in an alternating fashion. For example, one row of loops may be disposed between two adjacent rows of rungs and one row of rungs may be disposed between two adjacent rows of loops. The plurality of rows of rungs <NUM> may be more flexible than the plurality of rows of loops <NUM> and as such may provide flexibility to the tubular scaffold <NUM> as a whole. In some embodiments, each of the plurality of rows of rungs <NUM> may extend a greater circumferential distance around the tubular scaffold <NUM> than each of the plurality of rows of loops <NUM>. Other configurations are also contemplated. In some embodiments, the tubular scaffold <NUM>, the single filament, and/or the plurality of rows of loops <NUM> and the plurality of rows of rungs <NUM> may be heat set in the expanded configuration such that the endoprosthesis <NUM> and/or the tubular scaffold <NUM> is self-biased toward the expanded configuration.

Each row of loops of the plurality of rows of loops <NUM> extends longitudinally along the tubular scaffold <NUM> between the proximal end <NUM> and the distal end <NUM>. In some embodiments, at least some of the rows of loops of the plurality of rows of loops <NUM> may extend continuously from the proximal end <NUM> to the distal end <NUM>. In some embodiments, some of the rows of loops of the plurality of rows of loops <NUM> may be discontinuous between the proximal end <NUM> and the distal end <NUM>. Each row of rungs of the plurality of rows of rungs <NUM> extends longitudinally along the tubular scaffold <NUM> between the proximal end <NUM> and the distal end <NUM>. In some embodiments, at least some of the rows of rungs of the plurality of rows of rungs <NUM> may extend continuously from the proximal end <NUM> to the distal end <NUM>. In some embodiments, some of the rows of rungs of the plurality of rows of rungs <NUM> may be discontinuous between the proximal end <NUM> and the distal end <NUM>.

In some embodiments, each loop of the plurality of rows of loops <NUM> may extend about <NUM> millimeters (mm), <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, etc. around the circumference (e.g., along an arc) of the tubular scaffold <NUM>. In some embodiments, each rung of the plurality of rows of rungs <NUM> may extend about <NUM> millimeters (mm), <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, etc. around the circumference (e.g., along an arc) of the tubular scaffold <NUM>. Other configurations are also contemplated.

The tubular scaffold <NUM> includes a first cutout region <NUM> extending along a majority of the length of the tubular scaffold <NUM>. In some embodiments, the first cutout region <NUM> may extend along at least <NUM>% of the length of the tubular scaffold <NUM>. In some embodiments, the first cutout region <NUM> may extend along at least <NUM>% of the length of the tubular scaffold <NUM>. In some embodiments, the first cutout region <NUM> may extend along at least <NUM>% of the length of the tubular scaffold <NUM>. In some embodiments, the first cutout region <NUM> may extend along at least <NUM>% of the length of the tubular scaffold <NUM>. In some embodiments, the first cutout region <NUM> may extend along at least <NUM>% of the length of the tubular scaffold <NUM>. In some embodiments, the first cutout region <NUM> may extend along at least <NUM>% of the length of the tubular scaffold <NUM>. Other configurations are also contemplated.

The first cutout region <NUM> is disposed between the proximal end <NUM> of the tubular scaffold <NUM> and the distal end <NUM> of the tubular scaffold <NUM>. The first cutout region <NUM> may define and extend continuously from a first proximal end <NUM> oriented toward the proximal end <NUM> of the tubular scaffold <NUM> and a first distal end <NUM> oriented toward the distal end <NUM> of the tubular scaffold <NUM>. In some embodiments, the first proximal end <NUM> may be disposed distal of the proximal end <NUM> of the tubular scaffold <NUM>. In some embodiments, the first distal end <NUM> may be disposed proximal of the distal end <NUM> of the tubular scaffold <NUM>.

The first cutout region <NUM> is formed by removing a medial portion of a first row of loops <NUM> of the plurality of rows of loops <NUM> and medial portions of rows of rungs <NUM> of the plurality of rows of rungs <NUM> immediately adjacent to the first row of loops <NUM> along the majority of the length of the tubular scaffold <NUM>. In some embodiments, the first row of loops <NUM> of the plurality of rows of loops <NUM> may be discontinuous along a medial region of the tubular scaffold <NUM> and rows of rungs <NUM> on opposite sides of the first row of loops <NUM> in a circumferential direction from the first row of loops <NUM> are discontinuous along the medial region of the tubular scaffold <NUM>.

The medial region of the tubular scaffold <NUM> may extend along a majority of the length of the tubular scaffold <NUM>. In some embodiments, the medial region of the tubular scaffold <NUM> may extend along at least <NUM>% of the length of the tubular scaffold <NUM>. In some embodiments, the medial region of the tubular scaffold <NUM> may extend along at least <NUM>% of the length of the tubular scaffold <NUM>. In some embodiments, the medial region of the tubular scaffold <NUM> may extend along at least <NUM>% of the length of the tubular scaffold <NUM>. In some embodiments, the medial region of the tubular scaffold <NUM> may extend along at least <NUM>% of the length of the tubular scaffold <NUM>. In some embodiments, the medial region of the tubular scaffold <NUM> may extend along at least <NUM>% of the length of the tubular scaffold <NUM>. In some embodiments, the medial region of the tubular scaffold <NUM> may extend along at least <NUM>% of the length of the tubular scaffold <NUM>. Other configurations are also contemplated.

The first cutout region <NUM> may be formed after heat setting the tubular scaffold <NUM>, the single filament, and/or the plurality of rows of loops <NUM> and the plurality of rows of rungs <NUM>. In at least some embodiments, forming the first cutout region <NUM> may cause the single filament to be discontinuous within the first cutout region <NUM> and/or along the length of the tubular scaffold <NUM>. Similarly, forming the first cutout region <NUM> may cause the first row of loops <NUM> and rows of rungs <NUM> immediately adj acent the first row of loops <NUM> to be discontinuous within the first cutout region <NUM> and/or along the length of the tubular scaffold <NUM>. In some embodiments, within the medial region of the tubular scaffold <NUM> the single filament may comprise a plurality of discontinuous segments <NUM>.

The discontinuous single filament may comprise and/or the plurality of discontinuous segments <NUM> may form a first plurality of terminal ends <NUM> extending along the first cutout region <NUM> and/or the medial region. The first plurality of terminal ends <NUM> may be in close proximity to one of the plurality of rows of loops <NUM> and/or a perimeter of the first cutout region <NUM>. For example, the first plurality of terminal ends <NUM> may be within about <NUM> millimeters (mm), <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, etc. of one of the plurality of rows of loops <NUM>. Since the tubular scaffold <NUM>, the single filament, and/or the plurality of rows of loops <NUM> and the plurality of rows of rungs <NUM> were heat set prior to forming the first cutout region <NUM> and/or prior to removing the medial portion of the first row of loops <NUM> of the plurality of rows of loops <NUM> and medial portions of rows of rungs <NUM> of the plurality of rows of rungs <NUM> immediately adjacent to the first row of loops <NUM> along the majority of the length of the tubular scaffold <NUM>, the tubular scaffold <NUM> is prevented from unraveling even when the medial portion(s) is removed and/or the first cutout region <NUM> is formed.

In some embodiments, the first cutout region <NUM> may be formed by removing several adjacent rows of loops of the plurality of rows of loops <NUM> and rows of rungs immediately adjacent the several adjacent rows of loops. In one example, the first cutout region <NUM> may be formed by removing two adjacent rows of loops, the row of rungs disposed between the two adjacent rows of loops, and the rows of rungs on either circumferential side of the two adjacent rows of loops. In another example, the first cutout region <NUM> may be formed by removing three adjacent rows of loops, the two rows of rungs disposed between the three adjacent rows of loops, and the rows of rungs on either circumferential side of the three adjacent rows of loops. Other configurations are also contemplated.

The tubular scaffold <NUM> includes a second cutout region <NUM> extending along a majority of the length of the tubular scaffold <NUM>. In some embodiments, the second cutout region <NUM> may extend along at least <NUM>% of the length of the tubular scaffold <NUM>. In some embodiments, the second cutout region <NUM> may extend along at least <NUM>% of the length of the tubular scaffold <NUM>. In some embodiments, the second cutout region <NUM> may extend along at least <NUM>% of the length of the tubular scaffold <NUM>. In some embodiments, the second cutout region <NUM> may extend along at least <NUM>% of the length of the tubular scaffold <NUM>. In some embodiments, the second cutout region <NUM> may extend along at least <NUM>% of the length of the tubular scaffold <NUM>. In some embodiments, the second cutout region <NUM> may extend along at least <NUM>% of the length of the tubular scaffold <NUM>. Other configurations are also contemplated.

The second cutout region <NUM> is disposed between the proximal end <NUM> of the tubular scaffold <NUM> and the distal end <NUM> of the tubular scaffold <NUM>. The second cutout region <NUM> may define and extend continuously from a second proximal end <NUM> oriented toward the proximal end <NUM> of the tubular scaffold <NUM> and a second distal end <NUM> oriented toward the distal end <NUM> of the tubular scaffold <NUM>. In some embodiments, the second proximal end <NUM> may be disposed distal of the proximal end <NUM> of the tubular scaffold <NUM>. In some embodiments, the second distal end <NUM> may be disposed proximal of the distal end <NUM> of the tubular scaffold <NUM>. In some embodiments, the second cutout region <NUM> may be circumferentially spaced apart from the first cutout region <NUM>. In some embodiments, the second cutout region <NUM> may be disposed on an opposite side of the tubular scaffold <NUM> from the first cutout region <NUM> relative to the central longitudinal axis A.

In some embodiments, the second cutout region <NUM> may be formed by removing a medial portion of a second row of loops <NUM> of the plurality of rows of loops <NUM> and medial portions of rows of rungs <NUM> of the plurality of rows of rungs <NUM> immediately adjacent to the second row of loops <NUM> along the majority of the length of the tubular scaffold <NUM>. The second row of loops <NUM> of the plurality of rows of loops <NUM> may be circumferentially spaced apart from the first row of loops <NUM> of the plurality of rows of loops <NUM>. In some embodiments, the second row of loops <NUM> of the plurality of rows of loops <NUM> may be disposed on an opposite side of the tubular scaffold <NUM> from the first row of loops <NUM> of the plurality of rows of loops <NUM> relative to the central longitudinal axis A. In some embodiments, the second row of loops <NUM> of the plurality of rows of loops <NUM> may be circumferentially opposite the first row of loops <NUM> of the plurality of rows of loops <NUM>. In some embodiments, the second row of loops <NUM> of the plurality of rows of loops <NUM> may be discontinuous along the medial region of the tubular scaffold <NUM> and rows of rungs <NUM> on opposite sides of the second row of loops <NUM> in a circumferential direction from the second row of loops <NUM> are discontinuous along the medial region of the tubular scaffold <NUM>.

The second cutout region <NUM> may be formed after heat setting the tubular scaffold <NUM>, the single filament, and/or the plurality of rows of loops <NUM> and the plurality of rows of rungs <NUM>. In at least some embodiments, forming the second cutout region <NUM> may cause the single filament to be discontinuous within the second cutout region <NUM> and/or along the length of the tubular scaffold <NUM>. Similarly, forming the second cutout region <NUM> may cause the second row of loops <NUM> and rows of rungs <NUM> immediately adjacent the second row of loops <NUM> to be discontinuous within the second cutout region <NUM> and/or along the length of the tubular scaffold <NUM>.

The discontinuous single filament may comprise and/or the plurality of discontinuous segments <NUM> may form a second plurality of terminal ends <NUM> extending along the second cutout region <NUM> and/or the medial region. The second plurality of terminal ends <NUM> may be in close proximity to one of the plurality of rows of loops <NUM> and/or a perimeter of the second cutout region <NUM>. For example, the second plurality of terminal ends <NUM> may be within about <NUM> millimeters (mm), <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, etc. of one of the plurality of rows of loops <NUM>. Since the tubular scaffold <NUM>, the single filament, and/or the plurality of rows of loops <NUM> and the plurality of rows of rungs <NUM> were heat set prior to forming the second cutout region <NUM> and/or prior to removing the medial portion of the second row of loops <NUM> of the plurality of rows of loops <NUM> and medial portions of rows of rungs <NUM> of the plurality of rows of rungs <NUM> immediately adjacent to the second row of loops <NUM> along the majority of the length of the tubular scaffold <NUM>, the tubular scaffold <NUM> is prevented from unraveling even when the medial portion(s) is removed and/or the second cutout region <NUM> is formed.

In some embodiments, the second cutout region <NUM> may be formed by removing several adjacent rows of loops of the plurality of rows of loops <NUM> and rows of rungs immediately adjacent the several adjacent rows of loops. In one example, the second cutout region <NUM> may be formed by removing two adjacent rows of loops, the row of rungs disposed between the two adjacent rows of loops, and the rows of rungs on either circumferential side of the two adjacent rows of loops. In another example, the second cutout region <NUM> may be formed by removing three adjacent rows of loops, the two rows of rungs disposed between the three adjacent rows of loops, and the rows of rungs on either circumferential side of the three adjacent rows of loops. Other configurations are also contemplated.

As shown in <FIG>, the endoprosthesis <NUM> includes a polymeric covering <NUM> extending along the tubular scaffold <NUM>. In some embodiments, the polymeric covering <NUM> may be fixedly secured to, bonded to, or otherwise attached about the entire circumference of the tubular scaffold <NUM>. For example, the polymeric covering <NUM> may be continuously attached to the tubular scaffold <NUM> about its entire length, width, and/or circumference. In some embodiments, anywhere the polymeric covering <NUM> touches the tubular scaffold <NUM>, the polymeric covering <NUM> may be fixedly secured to, bonded to, or otherwise attached to the tubular scaffold <NUM>. In some embodiments, portions of the tubular scaffold <NUM> may be embedded within the polymeric covering <NUM>. In some embodiments, the tubular scaffold <NUM> may be continuously and/or completely embedded within the polymeric covering <NUM>.

The polymeric covering <NUM> is uninterrupted along the first cutout region <NUM>. The polymeric covering <NUM> is uninterrupted along the second cutout region <NUM>. In some embodiments, the first plurality of terminal ends <NUM> and/or the second plurality of terminal ends <NUM> may be embedded within the polymeric covering <NUM>, as shown in the cross-sectional detail view of <FIG>. In some embodiments, the polymeric covering <NUM> may be continuous along the medial region of the tubular scaffold <NUM>.

In some embodiments, the polymeric covering <NUM> may extend along an entire length of the endoprosthesis <NUM> and/or the tubular scaffold <NUM>. In some embodiments, the polymeric covering <NUM> may extend along a portion of the length of the endoprosthesis <NUM> and/or the tubular scaffold <NUM>. In some embodiments, the polymeric covering <NUM> may extend discontinuously between the proximal end <NUM> of the endoprosthesis <NUM> and/or the tubular scaffold <NUM> and the distal end <NUM> of the endoprosthesis <NUM> and/or the tubular scaffold <NUM>. In some embodiments, the polymeric covering <NUM> may extend continuously from the proximal end <NUM> of the endoprosthesis <NUM> and/or the tubular scaffold <NUM> to the distal end <NUM> of the endoprosthesis <NUM> and/or the tubular scaffold <NUM>. In some embodiments, all cells of the plurality of cells may be completely covered by the polymeric covering <NUM>. Other configurations are also contemplated.

In use, when the endoprosthesis <NUM> is positioned within a body lumen, the polymeric covering <NUM> may form a substantially continuous outer covering disposed on and/or over the tubular scaffold <NUM>, thereby forming a barrier, such as a sealed interface, between the lumen of the endoprosthesis <NUM> and/or the tubular scaffold <NUM> and the wall of the body lumen positioned radially outward of the polymeric covering <NUM>. The polymeric covering <NUM> may isolate the lumen of the endoprosthesis <NUM> and/or the tubular scaffold <NUM> from the wall of the body lumen. The polymeric covering <NUM> may prevent tissue ingrowth into the lumen and/or the tubular scaffold <NUM> of the endoprosthesis <NUM> and thereby permit and/or aid removal of the endoprosthesis <NUM> and/or the tubular scaffold <NUM> from the body lumen. Some suitable examples of materials for the polymeric covering <NUM>, including but not limited to PTFE, silicone, and the like, are discussed below.

<FIG> illustrates a side view of the endoprosthesis <NUM> and/or the tubular scaffold <NUM> subjected to the lateral force LF, as would occur during inspiration/expiration and/or coughing, similar to the lateral force LF applied to the prior art knitted stent <NUM> in <FIG>. As seen in <FIG>, a portion of the endoprosthesis <NUM> and/or the tubular scaffold <NUM>, and/or some of the plurality of rows of loops <NUM> and some of the plurality of rows of rungs <NUM>, is deflected inward. This portion may travel longitudinally along the length of the endoprosthesis <NUM> and/or the tubular scaffold <NUM>, as would occur during forced inspiration/expiration and/or coughing. The first cutout region <NUM> and/or the second cutout region <NUM> (not visible), and the polymeric covering <NUM>, may permit the endoprosthesis <NUM> and/or the tubular scaffold <NUM> to deflect without incurring the same high stress concentrations that are found in the prior art knitted stent <NUM> of <FIG>. The deformation found in the prior art knitted stent <NUM> of <FIG> is reduced or removed. Instead of outward stress being exerted on the single filament and/or the tubular scaffold <NUM> of the endoprosthesis <NUM>, the endoprosthesis <NUM> and/or the tubular scaffold <NUM> may collapse in a generally uniform manner. The polymeric covering <NUM> may be flexible enough to allow the endoprosthesis <NUM> and/or the tubular scaffold <NUM> to absorb the stress is deform into a flattened orientation. Once the lateral force LF has been removed, the endoprosthesis <NUM> and/or the tubular scaffold <NUM> may return to its original orientation (e.g., the expanded configuration) and patency of the body lumen is maintained.

In another example, <FIG> illustrates the endoprosthesis <NUM> and/or the tubular scaffold <NUM> bent almost in half (approximately <NUM> degrees), to show that the kinking seen in the prior art knitted stent <NUM> of <FIG> is avoided. Testing of the endoprosthesis <NUM> has shown that the first cutout region <NUM>, the second cutout region <NUM> (not visible), and/or the polymeric covering <NUM> improved the flexibility and kink resistance of the endoprosthesis <NUM> and/or the tubular scaffold <NUM> compared to the prior art knitted stent <NUM>.

<FIG> illustrates aspects of a method of making the endoprosthesis <NUM>. The method may include knitting the tubular scaffold <NUM> on a mandrel from a single filament, the tubular scaffold <NUM> including the plurality of rows of loops <NUM> and the plurality of rows of rungs <NUM> arranged around the central longitudinal axis A in an alternating fashion. In some embodiments, the mandrel may be generally cylindrical in shape and/or circular in cross-section. Other shapes, cross-sections, and/or configurations are also contemplated.

The method may include heat setting the tubular scaffold <NUM> on the mandrel. In some embodiments, the method may include heat setting the tubular scaffold <NUM> on the mandrel in the expanded configuration. In some embodiments, the method may include heat setting the tubular scaffold <NUM> on a first mandrel in the collapsed configuration at a first temperature such that the tubular scaffold <NUM> and/or the endoprosthesis <NUM> is self-biased toward the collapsed configuration at the first temperature, and heat setting the tubular scaffold <NUM> on a second mandrel in the expanded configuration at a second temperature different from the first temperature such that the tubular scaffold <NUM> and/or the endoprosthesis <NUM> is self-biased toward the expanded configuration at the second temperature. Other configurations are also contemplated.

The method includes, after the heat setting step, removing the medial portion of the first row of loops of the plurality of rows of loops <NUM> and medial portions of rows of rungs immediately adjacent to the first row of loops along a majority of the length of the tubular scaffold <NUM> to form the first cutout region <NUM>. In some embodiments, the method may include, after the heat setting step, removing the medial portion of the second row of loops of the plurality of rows of loops <NUM> and medial portions of rows of rungs immediately adjacent to the second row of loops along a majority of the length of the tubular scaffold <NUM> to form the second cutout region <NUM>. As discussed herein, the second cutout region <NUM> may be circumferentially spaced apart from the first cutout region <NUM>.

The method includes, after the removing step(s), applying the polymeric covering <NUM> to the tubular scaffold <NUM>, wherein the polymeric covering <NUM> is uninterrupted along the first cutout region <NUM> and optionally the second cutout region <NUM>. In some embodiments, the polymeric covering <NUM> may be applied via spray coating, dip coating, shrink wrap, and/or other suitable methods. In some embodiments, the polymeric covering <NUM> may be formed from silicone. In some embodiments, a thickness of the polymeric covering <NUM> may vary along the length of the endoprosthesis <NUM> and/or the tubular scaffold <NUM>. In one example, the thickness of the polymeric covering <NUM> may be increased along and/or within the first cutout region <NUM> and/or the second cutout region <NUM> compared to a remainder of the endoprosthesis <NUM> and/or the tubular scaffold <NUM>. In another example, the thickness of the polymeric covering <NUM> may be increased along the first plurality of terminal ends <NUM> and/or the second plurality of terminal ends <NUM>. Other configurations and/or materials are also contemplated.

In some embodiments, prior to applying the polymeric covering <NUM> to the tubular scaffold <NUM>, the method may include securing and/or fixedly attaching the first plurality of terminal ends <NUM> and/or the second plurality of terminal ends <NUM> to an immediately adjacent row of loops of the plurality of rows of loops <NUM>. In some embodiments, the first plurality of terminal ends <NUM> and/or the second plurality of terminal ends <NUM> may be welded (e.g., laser welded, sonic welded, etc.) to an immediately adjacent row of loops of the plurality of rows of loops <NUM>. Other configurations are also contemplated.

<FIG> illustrates an alternative configuration of the endoprosthesis <NUM>. The endoprosthesis <NUM> may be constructed substantially as described above, with changes noted below. The tubular scaffold <NUM> includes a plurality of cutout regions <NUM> extending along a majority of the length of the tubular scaffold <NUM>. In some embodiments, the plurality of cutout regions <NUM> may include two cutout regions, three cutout regions, four cutout regions, five cutout regions, etc..

In some embodiments, the plurality of cutout regions <NUM> may extend along at least <NUM>% of the length of the tubular scaffold <NUM>. In some embodiments, the plurality of cutout regions <NUM> may extend along at least <NUM>% of the length of the tubular scaffold <NUM>. In some embodiments, the plurality of cutout regions <NUM> may extend along at least <NUM>% of the length of the tubular scaffold <NUM>. In some embodiments, the plurality of cutout regions <NUM> may extend along at least <NUM>% of the length of the tubular scaffold <NUM>. In some embodiments, the plurality of cutout regions <NUM> may extend along at least <NUM>% of the length of the tubular scaffold <NUM>. In some embodiments, the plurality of cutout regions <NUM> may extend along at least <NUM>% of the length of the tubular scaffold <NUM>. Other configurations are also contemplated.

The plurality of cutout regions <NUM> may be disposed between the proximal end <NUM> of the tubular scaffold <NUM> and the distal end <NUM> of the tubular scaffold <NUM>. The plurality of cutout regions <NUM> may each define a proximal end oriented toward the proximal end <NUM> of the tubular scaffold <NUM> and a distal end oriented toward the distal end <NUM> of the tubular scaffold <NUM>. In some embodiments, the proximal end of the plurality of cutout regions <NUM> may be disposed distal of the proximal end <NUM> of the tubular scaffold <NUM>. In some embodiments, the distal end of the plurality of cutout regions <NUM> may be disposed proximal of the distal end <NUM> of the tubular scaffold <NUM>.

In some embodiments, the plurality of cutout regions <NUM> may each be formed by removing a medial portion of one row of loops <NUM> of the plurality of rows of loops <NUM> and medial portions of rows of rungs <NUM> of the plurality of rows of rungs <NUM> immediately adj acent to the one row of loops <NUM> along the majority of the length of the tubular scaffold <NUM>. In some embodiments, the one row of loops <NUM> of the plurality of rows of loops <NUM> may be discontinuous along a medial region of the tubular scaffold <NUM> and rows of rungs <NUM> on opposite sides of the one row of loops <NUM> in a circumferential direction from the one row of loops <NUM> are discontinuous along the medial region of the tubular scaffold <NUM>.

The plurality of cutout regions <NUM> may be formed after heat setting the tubular scaffold <NUM>, the single filament, and/or the plurality of rows of loops <NUM> and the plurality of rows of rungs <NUM>. In at least some embodiments, forming the plurality of cutout regions <NUM> may cause the single filament to be discontinuous within the plurality of cutout regions <NUM> and/or along the length of the tubular scaffold <NUM>. Similarly, forming the plurality of cutout regions <NUM> may cause the one row of loops <NUM> and rows of rungs <NUM> immediately adjacent the one row of loops <NUM> to be discontinuous within their respective cutout region <NUM> and/or along the length of the tubular scaffold <NUM>. In some embodiments, within the medial region of the tubular scaffold <NUM> the single filament may comprise a plurality of discontinuous segments.

The discontinuous single filament may comprise and/or the plurality of discontinuous segments may form a plurality of terminal ends extending along the plurality of cutout regions <NUM> and/or the medial region. The plurality of terminal ends may be in close proximity to one of the plurality of rows of loops <NUM> and/or a perimeter of the plurality of cutout regions <NUM>. For example, the plurality of terminal ends <NUM> may be within about <NUM> millimeters (mm), <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, etc. of one of the plurality of rows of loops <NUM>. Since the tubular scaffold <NUM>, the single filament, and/or the plurality of rows of loops <NUM> and the plurality of rows of rungs <NUM> were heat set prior to forming the plurality of cutout regions <NUM> and/or prior to removing the medial portion of the one row of loops <NUM> of the plurality of rows of loops <NUM> and medial portions of rows of rungs <NUM> of the plurality of rows of rungs <NUM> immediately adjacent to the one row of loops <NUM> along the majority of the length of the tubular scaffold <NUM>, the tubular scaffold <NUM> is prevented from unraveling even when the medial portion(s) is removed and/or the plurality of cutout regions <NUM> is formed.

In some embodiments, the plurality of cutout regions <NUM> may be circumferentially spaced apart from each other. In some embodiments, the plurality of cutout regions <NUM> may be equally circumferentially spaced apart around the circumference of the tubular scaffold <NUM> and/or the endoprosthesis <NUM>. In some embodiments, the plurality of cutout regions <NUM> may be unequally circumferentially spaced apart around the circumference of the tubular scaffold <NUM> and/or the endoprosthesis <NUM>. The endoprosthesis <NUM> includes the polymeric covering <NUM> as described herein.

In some embodiments, the polymeric covering <NUM> may be uninterrupted along and/or within the plurality of cutout regions <NUM>. In some embodiments, the polymeric covering <NUM> may be uninterrupted along and/or within at least some of the plurality of cutout regions <NUM>. In some embodiments, the polymeric covering <NUM> may be uninterrupted along and/or within each and/or all of the plurality of cutout regions <NUM>. In some embodiments, the plurality of terminal ends may be embedded within the polymeric covering <NUM>. In some embodiments, the polymeric covering <NUM> may be continuous along the medial region of the tubular scaffold <NUM>.

In an alternative configuration, the plurality of cutout regions <NUM> may each be formed by removing a medial portion of only one row of rungs of the plurality of rows of rungs <NUM> along the majority of the length of the tubular scaffold <NUM>. In some embodiments, the plurality of cutout regions <NUM> may be formed without removing any portion(s) of the plurality of rows of loops <NUM>. As such, the plurality of rows of loops <NUM> may each be continuous from the proximal end <NUM> to the distal end <NUM> and each row of rungs having a cutout region formed therein may be discontinuous between the proximal end <NUM> and the distal end <NUM>. Other configurations are also contemplated.

<FIG> illustrates an example placement of the endoprosthesis <NUM> within the trachea <NUM>. In some embodiments, the first cutout region <NUM> and/or the second cutout region <NUM> may be disposed and/or arranged along the lateral walls <NUM> of the trachea <NUM>. In this position, as the trachea <NUM> and/or the lumen <NUM> thereof is deformed by the trachealis muscle <NUM> (not shown) during forced inspiration/expiration and/or coughing, the endoprosthesis <NUM> may deflect and/or deform sufficiently to mitigate the high stresses formed at the corner spines <NUM> of the prior art knitted stent <NUM> (e.g., <FIG>), thereby reducing the effects of fatigue and increasing the longevity of the endoprosthesis <NUM>.

The materials that can be used for the various components of the endoprosthesis <NUM> and the various elements thereof disclosed herein may include those commonly associated with medical devices. For simplicity purposes, the following discussion makes reference to the endoprosthesis. However, this is not intended to limit the devices and methods described herein, as the discussion may be applied to other elements, members, components, or devices disclosed herein, such as, but not limited to, the tubular scaffold, the polymeric cover, and/or elements or components thereof.

In some embodiments, the endoprosthesis and/or components thereof may be made from a metal, metal alloy, polymer (some examples of which are disclosed below), a metal-polymer composite, ceramics, combinations thereof, and the like, or other suitable material.

Some examples of suitable polymers may include polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), polyoxymethylene (POM, for example, DELRIN® available from DuPont), polyether block ester, polyurethane (for example, Polyurethane 85A), polypropylene (PP), polyvinylchloride (PVC), polyether-ester (for example, ARNITEL® available from DSM Engineering Plastics), ether or ester based copolymers (for example, butylene/poly(alkylene ether) phthalate and/or other polyester elastomers such as HYTREL® available from DuPont), polyamide (for example, DURETHAN® available from Bayer or CRISTAMID® available from Elf Atochem), elastomeric polyamides, block polyamide/ethers, polyether block amide (PEBA, for example 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 (for example REXELL®), polyester, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polytrimethylene terephthalate, polyethylene naphthalate (PEN), polyetheretherketone (PEEK), polyimide (PI), polyetherimide (PEI), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), poly paraphenylene terephthalamide (for example, KEVLAR®), polysulfone, nylon, nylon-<NUM> (such as GRILAMID® available from EMS American Grilon), perfluoro(propyl vinyl ether) (PFA), ethylene vinyl alcohol, polyolefin, polystyrene, epoxy, polyvinylidene chloride (PVdC), poly(styrene-b-isobutylene-b-styrene) (for example, SIBS and/or SIBS 50A), polycarbonates, polyurethane silicone copolymers (for example, ElastEon® from Aortech Biomaterials or ChronoSil® from AdvanSource Biomaterials), biocompatible polymers, other suitable materials, or mixtures, combinations, copolymers thereof, polymer/metal composites, and the like. In some embodiments the sheath can be blended with a liquid crystal polymer (LCP). For example, the mixture can contain up to about <NUM> percent LCP.

Some examples of suitable metals and metal alloys include stainless steel, such as 304V, <NUM>, and 316LV stainless steel; mild steel; nickel-titanium alloy such as linear-elastic and/or super-elastic nitinol; other nickel alloys such as nickel-chromium-molybdenum alloys (e.g., UNS: N06625 such as INCONEL® <NUM>, UNS: N06022 such as HASTELLOY® C-<NUM>®, UNS: N10276 such as HASTELLOY® C276®, other HASTELLOY® alloys, and the like), nickel-copper alloys (e.g., UNS: N04400 such as MONEL® <NUM>, NICKELVAC® <NUM>, NICORROS® <NUM>, and the like), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R30035 such as MP35-N® and the like), 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, and the like; cobalt-chromium alloys; cobalt-chromium-molybdenum alloys (e.g., UNS: R30003 such as ELGILOY®, PHYNOX®, and the like); platinum enriched stainless steel; titanium; platinum; palladium; gold; combinations thereof; or any other suitable material.

In some embodiments, a linear elastic and/or non-super-elastic nickel-titanium alloy may be in the range of about <NUM> to about <NUM> weight percent nickel, with the remainder being essentially titanium. of Kanagawa, Japan.

In at least some embodiments, portions or all of the endoprosthesis and/or components thereof may also be doped with, made of, or otherwise include a radiopaque material. Radiopaque materials are understood to be materials capable of producing a relatively bright image on a fluoroscopy screen or another imaging technique during a medical procedure. This relatively bright image aids the user of the endoprosthesis in determining its location. Some examples of radiopaque materials can include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloy, polymer material loaded with a radiopaque filler, and the like. Additionally, other radiopaque marker bands and/or coils may also be incorporated into the design of the endoprosthesis to achieve the same result.

In some embodiments, a degree of Magnetic Resonance Imaging (MRI) compatibility is imparted into the endoprosthesis and/or other elements disclosed herein. For example, the endoprosthesis and/or components or portions thereof may be made of a material that does not substantially distort the image and create substantial artifacts (i.e., gaps in the image). Certain ferromagnetic materials, for example, may not be suitable because they may create artifacts in an MRI image. The endoprosthesis or portions thereof may also be made from a material that the MRI machine can image. Some materials that exhibit these characteristics include, for example, tungsten, cobalt-chromium-molybdenum alloys (e.g., UNS: R30003 such as ELGILOY®, PHYNOX®, and the like), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R30035 such as MP35-N® and the like), nitinol, and the like, and others.

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

In some embodiments, the endoprosthesis and/or other elements disclosed herein may include and/or be formed from a textile material. Some examples of suitable textile materials may include synthetic yarns that may be flat, shaped, twisted, textured, preshrunk or un-shrunk. Synthetic biocompatible yarns suitable for use in the present disclosure include, but are not limited to, polyesters, including polyethylene terephthalate (PET) polyesters, polypropylenes, polyethylenes, polyurethanes, polyolefins, polyvinyls, polymethylacetates, polyamides, naphthalene dicarboxylene derivatives, natural silk, and polytetrafluoroethylenes. Moreover, at least one of the synthetic yarns may be a metallic yarn or a glass or ceramic yarn or fiber. Useful metallic yarns include those yarns made from or containing stainless steel, platinum, gold, titanium, tantalum, or a Ni-Co-Cr-based alloy. The yarns may further include carbon, glass, or ceramic fibers. Desirably, the yarns are made from thermoplastic materials including, but not limited to, polyesters, polypropylenes, polyethylenes, polyurethanes, polynaphthalenes, polytetrafluoroethylenes, and the like. The yarns may be of the multifilament, monofilament, or spun-types. The type and denier of the yarn chosen may be selected in a manner which forms a biocompatible and implantable prosthesis and, more particularly, a vascular structure having desirable properties.

In some embodiments, the endoprosthesis and/or other elements disclosed herein may include and/or be treated with a suitable therapeutic agent. Some examples of suitable therapeutic agents may include anti-thrombogenic agents (such as heparin, heparin derivatives, urokinase, and PPack (dextrophenylalanine proline arginine chloromethylketone)); anti-proliferative agents (such as enoxaparin, angiopeptin, monoclonal antibodies capable of blocking smooth muscle cell proliferation, hirudin, and acetylsalicylic acid); anti-inflammatory agents (such as dexamethasone, prednisolone, corticosterone, budesonide, estrogen, sulfasalazine, and mesalamine); antineoplastic/antiproliferative/anti-mitotic agents (such as paclitaxel, <NUM>-fluorouracil, cisplatin, vinblastine, vincristine, epothilones, endostatin, angiostatin and thymidine kinase inhibitors); anesthetic agents (such as lidocaine, bupivacaine, and ropivacaine); anticoagulants (such as D-Phe-Pro-Arg chloromethyl keton, an RGD peptide-containing compound, heparin, anti-thrombin compounds, platelet receptor antagonists, anti-thrombin antibodies, anti-platelet receptor antibodies, aspirin, prostaglandin inhibitors, platelet inhibitors, and tick antiplatelet peptides); vascular cell growth promoters (such as growth factor inhibitors, growth factor receptor antagonists, transcriptional activators, and translational promoters); vascular cell growth inhibitors (such as growth factor inhibitors, growth factor receptor antagonists, transcriptional repressors, translational repressors, replication inhibitors, inhibitory antibodies, antibodies directed against growth factors, bifunctional molecules consisting of a growth factor and a cytotoxin, bifunctional molecules consisting of an antibody and a cytotoxin); cholesterol-lowering agents; vasodilating agents; and agents which interfere with endogenous vasoactive mechanisms.

Claim 1:
An endoprosthesis (<NUM>) configured to shift between a collapsed configuration and an expanded configuration, the endoprosthesis comprising:
a tubular scaffold (<NUM>) formed from a single filament knitted about a central longitudinal axis and defining a length from a proximal end (<NUM>) to a distal end (<NUM>), the tubular scaffold (<NUM>) including a plurality of rows of loops (<NUM>) and a plurality of rows of rungs (<NUM>) arranged around the central longitudinal axis in an alternating fashion; and
a polymeric covering (<NUM>) extending along the tubular scaffold (<NUM>);
wherein each row of loops (<NUM>) extends longitudinally along the tubular scaffold (<NUM>) between the proximal end and the distal end;
wherein each row of rungs (<NUM>) extends longitudinally along the tubular scaffold (<NUM>) between the proximal end (<NUM>) and the distal end (<NUM>);
characterized in that the tubular scaffold includes:
a first cutout region (<NUM>) extending along a majority of the length of the tubular scaffold (<NUM>) and defining a first proximal end (<NUM>) oriented toward the proximal end (<NUM>) of the tubular scaffold (<NUM>) and a first distal (<NUM>) end oriented toward the distal end of the tubular scaffold; and
a second cutout region (<NUM>) extending along a majority of the length of the tubular scaffold (<NUM>) and defining a second proximal end (<NUM>) oriented toward the proximal end (<NUM>) of the tubular scaffold (<NUM>) and a second distal (<NUM>) end oriented toward the distal end (<NUM>) of the tubular scaffold (<NUM>);
wherein the polymeric covering (<NUM>) is uninterrupted along the first cutout region (<NUM>) and the second cutout region (<NUM>).