Patent Description:
Esophageal stents have been used to treat patients suffering from a range of malignant and non-malignant diseases. Most commonly, esophageal stents have been associated with the treatment of esophageal cancers. Esophageal stents have also been used to reduce symptoms resulting from non-esophageal tumors that grow to obstruct the esophagus and to treat benign esophageal disorders, including but not limited to refractory strictures, fistulas and perforations. In each of these cases, esophageal stents may provide mechanical support to the esophageal wall and may maintain luminal patency. Because of the structure of the esophagus and conditions such as peristalsis, esophageal stents have been prone to stent migration.

One way to reduce the risk of stent migration has been to expose bare metal portions of the stent to esophageal tissue. The open, braided structure of the stent may provide a scaffold that promotes tissue ingrowth into the stent. This tissue ingrowth may aid anchoring the stent in place and may reduce the risk of migration. In some cases, however, tissue ingrowth has been known to lead to reocclusion of the esophagus. In addition, esophageal stents anchored by tissue ingrowth cannot be moved or removed without an invasive procedure. To reduce tissue ingrowth, stents have been covered with a coating (e.g., made of a polymer, etc.) to create a physical barrier between the lumen and the esophageal wall. However, in some circumstance, such stents can have an unacceptable occurrence of migration, as compared to bare metal counterparts.

Another way to reduce the risk of stent migration has been to use a flared stent in the esophagus. However, stents having flares can have an unacceptable occurrence of migration.

Improved stents with, for example, improved resistance to migration, improved stent adhesion to the esophageal wall, and/or improved removability are desired. Previous tracheal stents, such as those discussed in <CIT> and <CIT> have incorporated bumps or other surface features incorporated into the stent itself. Another tracheal stent described in co-owned <CIT> provides a plurality of surface protrusions on the outer surface of the stent. <CIT> discloses an intraluminal prosthesis including an outer three-dimensional anti-migration structure that is attached to the outer wall of a covered stent to prevent migration.

Without limiting the scope of the present disclosure, a brief summary of some of the claimed embodiments is set forth below. Additional details of the summarized embodiments of the present disclosure and/or additional embodiments of the present disclosure may be found in the Detailed Description of the Invention below. A brief abstract of the technical disclosure in the specification is also provided. The abstract is not intended to be used for interpreting the scope of the claims.

The invention is defined in the claims. The present disclosure provides an endoprosthesis where a preferably polymeric coating has a number of surface features such as protrusions that are arranged in a micropattern. As used herein, a micropattern may include a regular or irregular
array of micro-scale features (e.g., protrusions such as micropillars). Generally, micro-scale feature means a feature having a dimension (e.g., length, width, or height) in a range of from about <NUM> micrometer to about <NUM> micrometers. Herein, unless the context indicates otherwise, micro-scale features are referred to as micropillars (e.g., extending from a base).

In at least one embodiment, an endoprosthesis, having an expanded state and a contracted state, includes a stent with a polymeric coating adhered to an outer surface of the stent. The stent has an inner surface defining a lumen. In at least one embodiment, the stent is a flared stent. The polymeric coating includes a base and a plurality of protrusions (e.g., micropillars, etc.) extending outwardly from the base. In at least one embodiment, the protrusions are arranged in a micropattern. When the endoprosthesis is expanded to the expanded state in a lumen defined by a vessel wall, the micropillars apply a force that creates an interlock between the vessel wall and the endoprosthesis.

Although not wishing to be bound by theory, tissue may engage a micropatterned coating as a result of one or more mechanisms. For example, tissue may interlock with a micropatterned coating having one or more micropillars by growing around and/or between the one or more micropillars. In one or more embodiments, a chemical bond mechanism may be formed between a tissue in contact with a micropatterned coating that may include, for example, a mucoadhesive gel. In one or more embodiments, engagement of tissue with a micropattern having an appropriate geometry may be by proximity attraction by van der Waals bonding.

The micropattern is specifically designed for a particular tissue in order to effectively interlock the stent with the tissue. In at least one embodiment, the micropattern is present along at least a portion of the endoprosthesis. In at least one embodiment, the protrusions of the micropattern can be uniform or the micropattern can be formed of protrusions having a first configuration and protrusions having at least a second configuration.

The protrusions may be micropillars and may be selected from a group including cylinders, rectangular prisms, and similar structures. In at least one embodiment, the protrusions of the micropattern are cylindrical micropillars, each cylindrical micropillar having a diameter and a height, wherein the diameter of each cylindrical micropillar is equal to its height. In at least one embodiment, the cylindrical micropillar has a lateral surface, wherein the lateral surface of the cylindrical micropillar is separated from the lateral surfaces of an adjacent micropillar by a distance greater than the diameter of the cylindrical micropillar. In at least one embodiment, the micropattern is a grid pattern.

In at least one embodiment, each protrusion of the micropattern has a first dimension and a second dimension, wherein the first dimension is between about <NUM> and <NUM> (e.g., between about <NUM> and <NUM>), wherein the second dimension is between about <NUM> and <NUM> (e.g., between about <NUM> and <NUM>), and wherein each protrusion is spaced apart from an adjacent protrusion by a distance, wherein a ratio between the distance and the first dimension is between about <NUM> and <NUM>. In at least one embodiment, each protrusion has a ratio between the first dimension and the second dimension that is between about <NUM> and <NUM>.

In at least one embodiment, the endoprosthesis is retrievable by, for example, a retrieval loop at a distal end of the stent.

Several methods of manufacturing an embodiment of the endoprosthesis are provided. One method of manufacturing includes forming a polymeric coating, wherein the polymeric coating includes a base and a plurality of protrusions extending outwardly from the base in a micropattern; providing a stent having an inner surface defining a lumen and an outer surface; and adhering the base of the polymeric coating to the outer surface of the stent. The polymeric coating can be formed using a mold having an inverse of the micropattern and injecting a polymeric material into the mold and, in some cases applying temperature or pressure to the mold, before the polymeric material cures; using soft lithography techniques, or by etching the polymeric coating from a layer of the polymeric material. In at least one embodiment, an adhesive layer is applied to at least one of a surface of the base and the outer surface of the stent. In at least one embodiment, the polymeric coating is formed as a tubular structure. In one or more embodiments, the polymeric coating is formed in a strip, which is wrapped (e.g., helically wrapped, circumferentially wrapped, randomly wrapped, etc.) about the outer surface of the stent.

<FIG> do not show embodiments of the invention.

While the subject matter of the present disclosure may be embodied in many different forms, there are described in detail herein specific preferred embodiments of the present disclosure. This description is an exemplification of the principles of the present disclosure and is not intended to limit the present disclosure to the particular embodiments illustrated.

For the purposes of this disclosure, like reference numerals in the figures shall refer to like features unless otherwise indicated.

The present disclosure relates to micropatterned polymeric coatings for use on medical devices. In some embodiments, the micropatterned polymeric coatings are utilized with implantable medical devices, such as stents, to reduce or prevent stent migration, particularly for stents used in the gastroesophageal system, including, but not limited to, esophageal, biliary, and colonic stents. The stents described in this application may be used in the trachea, the cardiovascular system, and elsewhere in the body (e.g., any body lumen).

<FIG> show an esophageal endoprosthesis <NUM> of the present disclosure with a proximal end <NUM> and a distal end <NUM>. The endoprosthesis <NUM> includes an expandable stent <NUM> and a polymeric coating <NUM>. Expandable stent <NUM> can be self-expanding, balloon expandable, or hybrid expandable. Embodiments of the expandable stent <NUM> contemplate stents having a constant diameter, tapers, flares and/or other changes in diameter in the body and/or at an end. The expandable stent <NUM> has an inner surface <NUM>, an outer surface <NUM>, a first end <NUM> and a second end <NUM>, and the polymeric coating <NUM> is disposed about at least a portion of the outer surface <NUM>. In at least one embodiment, the polymeric coating <NUM> substantially covers the entire outer surface <NUM> of the expandable stent <NUM>. In other embodiments, the polymeric coating <NUM> covers a portion of the outer surface <NUM> of the expandable stent <NUM>. As shown in <FIG>, the polymeric coating <NUM> can be directly connected to the outer surface <NUM> of the expandable stent <NUM>. In one or more embodiments, the polymeric coating <NUM> can be connected to the outer surface <NUM> of the expandable stent <NUM> using an adhesive or other means of attaching the coating to the device. In at least one embodiment, the polymeric coating at least partially covers the inner surface <NUM> also. In at least one embodiment, partial coverage can include partial coverage of the perimeter and/or the length.

In at least one embodiment, shown in <FIG> and <FIG>, the polymeric coating <NUM> includes a base <NUM> and a plurality of protrusions, such as micropillars <NUM>, extending outwardly from the base <NUM>. In at least one embodiment, the micropillars are seamlessly incorporated into the base of the coating. In at least one embodiment, the base <NUM> is coterminous with the expandable stent <NUM>. What is meant by "coterminous" is that the base <NUM> of the polymer coating <NUM> and the expandable stent <NUM> have the same boundaries, cover the same area, and are the same in extent. In other words, the expandable stent <NUM> and the base <NUM> each have first and second ends, and the expandable stent <NUM> and the base <NUM> extend between their first and second ends. The first end of the expandable stent <NUM> is the same as first end of the base <NUM>, and the second end of the expandable stent <NUM> is the same as the second end of the base <NUM>. Since the expandable stent <NUM> and the base <NUM> extend between their first and second ends, the expandable stent <NUM> and the base <NUM> have the same boundaries, cover the same area, and are the same in extent. Thus, the base <NUM> and the expandable stent <NUM> are coterminous. The expandable stent <NUM> and the base <NUM> therefore are coterminous in at least one embodiment. Also, base <NUM> is tubular in at least one embodiment.

In some embodiments as shown in <FIG>, the micropillars are cylinders (<FIG>), prisms with a rectangular or polygonal base (<FIG>), pyramids (<FIG>), bumps (<FIG>), or has a non-traditional shape with a plurality of bumps and ridges on multiple surfaces that do not define a cross-section that is circular, square, polygonal, etc. (<FIG>). Each micropillar can have a circular cross-section (<FIG>), square cross-section (<FIG>), rectangular cross-section (<FIG>), star-shaped cross-section (<FIG>), hexagonal cross-section (<FIG>), pentagonal cross-section (<FIG>), heptagonal (<FIG>), octagonal cross-section (<FIG>), nonagonal cross-section (<FIG>), decagonal cross-section (<FIG>), other polygonal cross-sections, or non-traditional shaped cross-sections. Each cross-section has a first dimension h that is the greatest distance between the outer surface of the base and the end of the pillar and a second dimension d that is the greatest distance between two opposite sides (e.g., of the pillar). For example, for the circular cross-section the second dimension d is the diameter, for the square d is between two sides, for the rectangle, the major dimension is between the two shorter sides, for the star, the major dimension is between two points, for the hexagon the major dimension is between two opposite points. In some embodiments, the second dimension d is between midpoints of two opposite sides. In at least one embodiment, a cross section of the micropillar taken in the radial direction has at least four sides. Embodiments of the present disclosure contemplate polygonal cross-sections having all sides of equal length, combinations of sides of equal length and unequal length, or all sides of unequal length. Embodiments of the present disclosure contemplate multiple pillars of multiple cross-sectional shapes including traditional shapes (e.g. circles, squares, rectangles, hexagons, polygons, etc.) and non-traditional shapes having a perimeter where at least a portion of the perimeter is curvilinear. In at least one embodiment, the micropillars are solid structures, but in other embodiments they can be hollow structures. In at least one embodiment, each micropillar has a constant cross-section, but in other embodiments the micropillars have variable cross-sections. In at least one embodiment, a micropillar extends perpendicularly from a base (e.g., <FIG>). In at least one embodiment, a micropillar extends from a base in a non-perpendicular angle (e.g., <FIG>) wherein geometric center <NUM> (see <FIG>) of the lateral surface <NUM> of the micropillar is offset laterally from the geometric center of the area of the base covered by the micropillar (e.g., <FIG>). In <FIG>, a longitudinal axis of the micropillar <NUM> extending through the geometric centers of the lateral cross-sections forms an angle that is less than <NUM> degrees with base <NUM>. In at least one embodiment, the plurality of micropillars <NUM> can be arranged in one or more particular micropatterns. Although not wishing to be bound by theory, the micropattern may affect the strength of the frictional engagement or interlock between the endoprosthesis and the vessel wall. Likewise, the micropattern is dependent upon the desired frictional engagement or interlock between the micropillars of the endoprosthesis and the tissue. For this reason, in at least one embodiment, a particular microstructure can be selected that has a micropattern geometry and dimensions suitable for a particular application (e.g., implantation site, biological tissue, desired tissue engagement properties, etc.).

It should be noted that the surface features of micropillars or holes described herein (e.g., bumps of <FIG>, bumps and ridges of <FIG>, etc.) may have one or more micro-scale or nano-scale (e.g., from about <NUM> nanometer to about <NUM> nanometers) dimensions.

In at least one embodiment, the micropillars in the micropattern all have the same shape, and in other embodiments, the micropillars vary in shape along the polymeric coating. Thus, in at least one embodiment, the micropattern can include portions where the micropillars have a first configuration and portions where the micropillars have a second configuration. Moreover, embodiments include the polymeric coating having only one micropattern or the polymeric coating having multiple micropatterns. Thus, the polymeric coating can be tailored to specific structural characteristics of the body lumen (e.g., a vessel, etc.) and a desired frictional engagement or interlock can be achieved, while using a single stent.

In at least one embodiment, the dimension d is between <NUM> and <NUM>. In at least one embodiment, the dimension d is between about <NUM> and <NUM>. In at least one embodiment, the dimension d is at least equal to the dimension h. In at least one embodiment, a ratio of h to d is between about <NUM> and <NUM>. In at least one embodiment, two adjacent micropillars are spaced apart by a distance s (shown in <FIG>). In at least one embodiment, the ratio of the spacing s to the dimension d is between about <NUM> and <NUM>.

In some embodiments, the ends of the protrusions, such as micropillars <NUM>, that are furthest away from the outer surface of the base can be shaped to improve tissue attachment. In one or more embodiments, the ends can be tapered, pointed, rounded, concave, convex, jagged, or frayed. The ends of each protrusion (micropillar <NUM>) can include a plurality of pillars on an even smaller scale than micropillars <NUM>.

In at least one embodiment, the protrusions such as micropillars <NUM> can also include features such as smooth surfaces, rough surfaces 55a (<FIG>), a plurality of bumps 55b extending outwardly from a surface of the micropillar (<FIG>), a plurality of indentations 55c extending inwardly from a surface of the micropillar (<FIG>), a plurality of ridges 55d on a surface of the micropillar (<FIG>), a tip 55e at or near the end of the protrusion that either softer or more rigid than the remainder of the protrusion (<FIG>), a frayed tip 55f (<FIG>), a convex (e.g., rounded) tip (<FIG>), a flared (e.g., flat top) tip (<FIG>), a concave (e.g., rounded) tip (<FIG>), a tip having a first dimension dt that is greater than a dimension d of the micropillar column extending between the base <NUM> and the tip (<FIG>), and other features that may impart desirable gripping, stiffness, or flexibility characteristics for the endoprosthesis, and any combination of features thereof. In at least one embodiment, the tip 55e can include a different material than the remainder of the protrusion.

<FIG> shows an enlarged view of the polymeric coating <NUM>. In at least one embodiment, the micropillars are cylinders that each have a diameter d and a height, h measured from an outer surface of the base <NUM> to a top surface of the cylinder <NUM>. In at least one embodiment, the diameter d is between <NUM> and <NUM> (e.g., between <NUM> and <NUM>, between <NUM> and <NUM>, between <NUM> and <NUM>, etc.). In at least one embodiment, the diameter d is between about <NUM> and <NUM>. In at least one embodiment, the diameter d of the micropillar is at least equal to its height h. In at least one embodiment, a ratio of height h of the micropillar <NUM> to diameter d of the micropillar is between about <NUM> and <NUM>. In at least one embodiment, the micropillars each have a lateral surface <NUM>. In at least one embodiment, two adjacent micropillars are spaced apart. The micropillars should be spaced apart enough so that the tissue of the bodily vessel can fill the negative space (e.g., void space) between the pillars. If the spacing is too small, the tissue may not be able to actually interlock. In at least one embodiment, the spacing between the micropillars is dependent upon (e.g., may be selected based upon) the particular type of tissue of the bodily vessel. In at least one embodiment, the spacing s measured between the centers <NUM> of one micropillar and an adjacent micropillar is greater than the diameter d of the one micropillar. In at least one embodiment, the ratio of the spacing s to the diameter d is between about <NUM> and <NUM>.

In at least one embodiment, the micropillars are spaced apart equidistantly in the micropattern. In at least one embodiment, the micropattern of micropillars is a rectangular array (e.g., <FIG>, <FIG>). In at least one embodiment, the micropattern is a grid pattern (e.g., a square array as in <FIG>, <FIG>). In at least one embodiment, the micropattern is a regular n-polygonal array (e.g., hexagonal array in <FIG>), wherein a micropillar may be present in the center of the polygon (e.g., <FIG>, etc.) or may not be present in the center of the polygon (e.g., <FIG>). In other words, in the micropattern, the micropillars are arranged in rows and columns in the micropattern, wherein the rows and columns may or may not be perpendicular. For example, the micropattern of <FIG> includes rows and columns that are perpendicular, whereas the micropattern of <FIG> includes rows and columns that are not perpendicular. In one or more embodiments, each micropillar has a longitudinal axis and the micropillars are axially aligned in at least one of the axial direction (e.g., arranged in a row parallel to a longitudinal axis of a stent) and the circumferential direction of the endoprosthesis (e.g., arranged in a row extending circumferentially around a longitudinal axis of a stent). In at least one embodiment, the micropattern of micropillars includes any or all of the features described in this paragraph. In some embodiments, like the embodiments shown in 10A and 10B, the micropattern may cover only a portion of the base <NUM> rather than the entire base <NUM>. The micropattern of micropillars may be helically disposed on the base <NUM>, as shown in <FIG>. In one or more embodiments, as shown in <FIG>, a first micropattern may be disposed longitudinally along the base <NUM> and a second micropattern is disposed circumferentially about the base so that the micropattern forms a "window pane"-like configuration. As depicted in <FIG>, the micropillars arranged in a row (e.g., parallel to a longitudinal axis of a stent) may be continuous rows or discontinuous rows (e.g., aligned row segments separated by a gap having a dimension greater than s), wherein the length of the discontinuity may have any length (e.g., <NUM> or more times the dimension s). For example, the embodiment depicted in <FIG> shows discontinuous rows (and circumferentially oriented columns) extending across the window panes wherein the length of the discontinuity is five times the dimension s (see <FIG>) whereas the embodiment depicted in <FIG> shows discontinuous rows (and nonperpendicularly oriented columns) wherein the length of the discontinuity is two times the dimension s (see <FIG>). In terms of the dimension s shown in <FIG>, a row and/or column discontinuity may have any length (e.g., at least <NUM> times s, at least <NUM> times s, at least <NUM> times s, at least <NUM> times s, at least <NUM> times s, at least <NUM> times s, at least <NUM> times s, etc.).

Regarding the material used for the polymeric coating <NUM>, it is important that the material be flexible enough to create an effective interlock with the tissue and be able to withstand the processing for creating the polymer coating <NUM>. Examples of acceptable materials include, but are not limited to, flexible silicones, hydrogels, mucoadhesive substrate, pressure-sensitive adhesives, and other suitable elastomers, such as synthetic rubbers. Other acceptable materials include any flexible, biocompatible, and non-biodegradable polymer. In at least one embodiment, the polymeric coating <NUM> (e.g., having micropillars <NUM>) may include proteins capable of engaging the tissue wall in a biochemical manner. In at least one embodiment, the polymeric coating <NUM> may include at least one therapeutic agent. In other embodiments, an additional coating may be applied to the polymeric coating <NUM> that includes a therapeutic agent. A therapeutic agent may be a drug or other pharmaceutical product such as non-genetic agents, genetic agents, cellular material, etc. Some examples of suitable non-genetic therapeutic agents include but are not limited to: anti-thrombogenic agents such as heparin, heparin derivatives, vascular cell growth promoters, growth factor inhibitors, paclitaxel, etc. Where an agent includes a genetic therapeutic agent, such a genetic agent may include but is not limited to: DNA, RNA and their respective derivatives and/or components; hedgehog proteins, etc. Where a therapeutic agent includes cellular material, the cellular material may include but is not limited to: cells of human origin and/or non-human origin as well as their respective components and/or derivatives thereof.

In a preferred embodiment, the micropillars <NUM> and the base <NUM> are formed from the same material. In one or more embodiments, the micropillars <NUM> are formed from one material and the base <NUM> is formed from a different material. In one or more embodiments, the micropillars <NUM> are formed with layers of material, and these layers can be the same material or can be different materials depending on the characteristics required for the desired frictional engagement of the endoprosthesis with the vessel wall.

Because the endoprosthesis <NUM> has improved frictional engagement with the tissue wall when inserted into a lumen of the patient, removal of the stent may be more difficult with some traditional removal techniques. In at least one embodiment, shown in <FIG>, the endoprosthesis <NUM> is provided with a suture or removal loop <NUM> on one end of the stent. In at least one embodiment, the removal loop <NUM> is provided on a distal end of the stent. It should be noted that references herein to the term "distal" are to a direction away from an operator of the devices of the present disclosure, while references to the term "proximal" are to a direction toward the operator of the devices of the present disclosure. While sutures or removal loops are well known in the art for removing endoprosthesis, typically sutures or removal loops are provided on the proximal end of the stent, in other words the closest end to the practitioner. Here, the suture or removal loop is applied to the opposite end of the endoprosthesis. In at least one embodiment, the practitioner grabs the loop from inside the endoprosthesis, and by applying an axial force to the loop, the distal end of the endoprosthesis is pulled through the lumen of the endoprosthesis itself. Thus, the micropillars are peeled away from the vessel wall while the stent is flipped inside out to remove the endoprosthesis. In other embodiments, the practitioner may grab the loop from outside the endoprosthesis or at an end of the endoprosthesis.

To manufacture the endoprosthesis <NUM>, several methods can be employed. The polymeric coating <NUM> can be molded separately from the stent and then adhered to the stent with an adhesive layer <NUM> between the outer surface of the endoprosthesis and the base of the polymeric coating. Polymeric material can be injected into a mold with the inverse of the micropattern to create the polymeric coating. Also, the polymeric material can be pulled through a mold using a vacuum pump system. In at least one embodiment, the polymeric coating can be created using soft lithography techniques. In one or more embodiments, etching techniques can be used to create the coating, wherein material is taken away from a layer of the coating material to create the micropattern of the polymeric coating <NUM>. In yet another embodiment, a technique called hot embossing can be used, which involves stamping partially cured polymer into the desired shape of the polymeric coating and then curing it before it is applied to the stent. Stamping may or may not include the use of a solvent.

In at least one embodiment, as shown in <FIG>, the coating <NUM> can be molded as a substantially tubular structure with a lumen defined by the base of the coating. An adhesive layer <NUM> can be applied to either the stent or to at least a portion of the inner surface of the base of the coating. In at least one embodiment, the adhesive layer <NUM> may substantially cover the entire inner surface of the base of the coating. The stent <NUM> can be inserted into the lumen of the coating <NUM>. In at least one embodiment, heat and/or pressure may be applied to ensure proper adhesion of the coating <NUM> to the stent <NUM> via the adhesive layer <NUM>. The adhesive layer may include silicone coatings, other suitable adhesives, or priming solutions that enable the coating to adhere to the metal stent (or stent coating thereon). In one or more embodiments, as shown in <FIG>, rather than being molded as a tubular structure, the coating <NUM> can be molded as a strip attached to the outer surface <NUM> of the stent <NUM>. In some embodiments, the strip can be applied as perimeter strips attached circumferentially about at least a portion of the circumferential perimeter of the stent. In some embodiments, the strip can be a longitudinal strip attached to the stent in a longitudinal direction. In some embodiments, the stent can be helically wrapped about the stent, as shown in <FIG>. In some embodiments the coating may be applied as a single strip or as multiple strips. Where the coating is applied as multiple strips, directly adjacent strips may abut one another or may be spaced apart from one another. In at least one embodiment, the strips may be partial tubular structures that extend along the length of the stent but only cover a portion of the circumference of the stent. In some embodiments, a portion of stent <NUM> may be exposed. An adhesive layer <NUM> can be applied to either the stent or to at least a portion of the base of the coating. In at least one embodiment, heat and/or pressure may be applied to ensure proper adhesion of the coating <NUM> to the stent <NUM> via the adhesive layer <NUM>. In at least one embodiment, discrete micropatterns of micropillars can be formed on and/or attached directly to either the stent <NUM> or the polymeric coating <NUM>.

Claim 1:
An endoprosthesis (<NUM>) having an expanded state and an unexpanded state, the endoprosthesis comprising:
a stent (<NUM>), wherein the stent has an inner surface (<NUM>) defining a lumen, an outer surface (<NUM>), a proximal end (<NUM>), a distal end (<NUM>), and a thickness defined between the inner surface and the outer surface, wherein the stent has a plurality of openings extending through the thickness; and
a polymeric coating (<NUM>) adhered to the outer surface of the stent, the polymeric coating comprising a base (<NUM>) and a plurality of protrusions extending outwardly from the base, wherein the protrusions are arranged in a micropattern,
characterized in that the polymeric coating is formed in at least one strip wrapped about the outer surface of the stent, and wherein a portion of the stent is exposed and not covered by the at least one strip.