BRIEF DESCRIPTION OF THE DRAWINGS
Additional features, advantages and possible applications of the present disclosure are derived from the following description of exemplary embodiments on the basis of the drawings. All the features described and/or illustrated here may constitute the subject of the disclosure either alone or in any combination, regardless of how they are combined in individual claims or the reference back to them.
FIG. 1
a is a schematic view of a detail of a proximal or distal end section of a first exemplary embodiment of a stent shown in a view from the side with partial sectional views through the basic mesh of the stent in the area of the carrier structure, through the carrier structure and through the functional element;
FIG. 1
b is a schematic view of a proximal or distal end section of the exemplary embodiment of FIG. 1;
FIG. 2 is a schematic detail view of a proximal or distal end section of another exemplary embodiment of a stent shown in a view from the side with partial sectional views through the basic mesh of the stent in the area of the carrier structure, through the carrier structure and through the functional element;
FIG. 3 is a schematic view of the finger-shaped carrier structures of FIGS. 1a and 1b;
FIG. 4 is a schematic view of a detail of a proximal or distal end section of a further exemplary embodiment of a stent shown in a view from the side with partial sectional views through the basic mesh of the stent in the area of the carrier structure, through the carrier structure and through the functional element;
FIG. 5 is a schematic view of a detail of a proximal or distal end section of an additional exemplary embodiment of a stent shown in a view from the side with partial sectional views through the basic mesh of the stent in the area of the carrier structure, through the carrier structure and through the functional element;
FIG. 6 is a schematic view of a detail of a proximal or distal end section of yet another exemplary embodiment of a stent shown in a view from the side with partial sectional views through the basic mesh of the stent in the area of the carrier structure, through the carrier structure and through the functional element;
FIG. 7 is a schematic view of a longitudinal section through a basic mesh section of an additional exemplary embodiment of a stent having a longitudinal section through a carrier structure and a functional element; and
FIG. 8 is a schematic view of a detail of the stent wall of another exemplary embodiment of a stent in a view from the side.
DETAILED DESCRIPTION
The detail of an end section of the first exemplary embodiment shown in FIG. 1a is a basic mesh 3 with webs 4 running in the longitudinal direction L and zigzag or meandering webs 5. The zigzag or meandering pleated webs 5 are connected to the webs 4 running in the longitudinal direction L and together with the webs 4 form the basic structure of the stent, which is shaped on the whole as tubes running in the longitudinal direction L.
The basic structure of the stent preferably consists of a metallic material consisting of one or more metals from the group consisting of iron, magnesium, nickel, tungsten, titanium, zirconium, niobium, tantalum, zinc, silicon, combinations thereof and the like and optionally a second component from one or more metals from the group consisting of lithium, sodium, potassium, calcium, manganese, iron, tungsten, combinations thereof and the like, preferably a zinc-calcium alloy. In another exemplary embodiment, the basic mesh 3 consists of a memory material comprising one or more materials from the group consisting of nickel-titanium alloys and copper-zinc-aluminum alloys; the basic mesh 3 preferably consists of nitinol. In another preferred exemplary embodiment, the basic mesh 3 of the stent is made of stainless steel or, even more preferably, made of alloy 316L, preferably from a Cr—Ni—Fe steel or a Co—Cr steel. Furthermore, the basic mesh of the stent may be made at least partially of plastic and/or a ceramic.
In another exemplary embodiment the basic mesh consists of an absorbable magnesium alloy having the following composition:
- rare earths 2.0 to 30.0 weight-percent,
- yttrium 0.0 to 20.0 weight-percent,
- zirconium 0.3 to 5 weight-percent,
- remainder 0 to 10.0 weight-percent (optionally neodymium),
whereby magnesium (at least 60.0 weight-percent) constitutes the remainder of the alloy to a total of 100 weight-percent.
The stent basic mesh 3 is produced by first providing a base body in the form of a hollow cylinder (tube) from which the structure of the basic mesh is produced, e.g., by means of a cutting technique, preferably by laser beam cutting or water jet cutting, or by chemical or electrochemical etching methods, with or without the use of lithographic techniques. Then the surface of the stent basic mesh can be machined, especially finished, smoothed and/or polished.
Finger-shaped carrier structures 6 are attached to the zigzag or meandering webs 5 arranged at the farthest point in the direction of the proximal or distal end of the stent illustrated in FIG. 1a. Along a direction k, which indicates the direction of extent of the longitudinal axis of the carrier structure and which runs, in this case, parallel to the longitudinal direction L of the stent, the carrier structures 6 have their greatest extent. The carrier structures 6 may have a cylindrical or cubic shape, for example, so that the cross section perpendicular to the direction k is designed to be essentially rectangular or round. The carrier structures 6 are attached to the web 5 at the first finger-shaped end along the direction k and protrude in the longitudinal direction L away from the basic mesh 3 of the stent such that the second protruding end of the carrier structure 6 is directed away from the basic mesh 3.
By analogy with the carrier structure 6, another finger-shaped carrier structure 6′ is arranged with the finger-shaped end on the zigzag or meandering web 5. This carrier structure 6′ protrudes away from the web 5 in the longitudinal direction L of the stent such that the second end in the longitudinal direction k of the carrier structure 6′ points in the direction of the basic mesh. In this way, this carrier structure 6′ is “framed” by the zigzag or meandering web 5 in the area of the stent wall, i.e., the meandering areas of the stent 5 surround the carrier structure 6′ on three sides in the area of the stent wall. Because of the attachment of the carrier structure 6, 6′ to the basic mesh 3 at their first finger-shaped end, the respective carrier structure 6, 6′ can be adapted flexibly to the movements of the zigzag or meandering web 5.
In one exemplary embodiment in FIG. 1b, two or more carrier structures 6″ protrude essentially away from the web 5 in the longitudinal direction L of the stent.
A functional element 8 having a spherical shape on the second end opposite the first end in the longitudinal direction is arranged on the carrier structures 6, 6′ on the second end opposite the first end in the longitudinal direction of the carrier structure 6, 6′. The functional element 8 surrounds the second end of the carrier structure 6, 6′ completely. In another exemplary embodiment, the functional element 8 may also have a disk shape whereby the circular cross section extends essentially in a plane running tangentially to the lateral surface of the cylindrical stent (tangential plane). The spherical functional element 8 completely surrounds the end of the carrier structure 6, 6′ protruding away from the basic mesh. In this way, the largest possible extent of the functional element in the direction of the tangential plane is achieved.
The functional element 8 may contain radiopaque material, preferably one or more of the radiopaque elements indicated above and/or one or more of the radiopaque compounds listed above. Examples of the material of the functional element are also listed above.
Additionally or alternatively, the functional element 8 may contain pharmaceutically active substances having an anti-inflammatory, antiproliferative and/or spasmolytic effect and consisting of, for example, the aforementioned group of active ingredients, which may be bonded to the carrier structure 6, 6′ with the help of a carrier matrix, preferably a polymer. After implantation of the stent, these active ingredients can elute into the body tissue and manifest their anti-inflammatory, antiproliferative and/or spasmolytic effects in the body tissue. In an especially preferred exemplary embodiment, the functional elements designed as an active ingredient depot are arranged so the functional elements are uniformly distributed over the entire wall of the mesh structure.
In one exemplary embodiment, the carrier structures 6, 6′ are made of an insulating material, e.g., a ceramic or a plastic.
In the exemplary embodiment shown in FIG. 2, the carrier structures 16 are shown; they are designed to be finger shaped at the first end and are attached at the first end to the basic mesh 3 of the stent. On the second end, the carrier structures 16 each have two fingers 17 protruding laterally, i.e., perpendicular to the direction k. The carrier structure 16 thus forms a cross shape at the second end. The carrier structure 16 is connected to the zigzag or meandering web 5. Another carrier structure 16′, having a similar design, is connected at the first finger-shaped end to the web 4 of the basic mesh 3 running in the longitudinal direction L and protrudes away from the web 4 in the tangential plane essentially perpendicular to the longitudinal direction L.
In the case of the carrier structure 16, the functional element 18 arranged at the end of the carrier structure 16 and protruding away from the basic mesh 3 of the stent is designed to be essentially spherical or disk-shaped by analogy with the exemplary embodiment depicted in FIGS. 1a or 1b. The functional elements 18′ provided on the carrier structures 16′ are essentially droplet-shaped, each surrounding the second end of the carrier structure 16′ including the finger 17′ protruding laterally away at a right angle to the direction k.
The carrier structure 26 depicted in FIG. 3 corresponds to the finger-shaped carrier structures 6, 6′ from FIGS. 1a or 1b which are arranged on the zigzag or meandering webs 5 situated the greatest distance away in the direction of the end of the stent in the areas of these webs 5 which are curved inward in the direction of the basic mesh 3 (concave section). The zigzag or meandering webs 5 thus surround the carrier structures 6, and the functional elements 28 attach to the second end of the carrier structure 26 in the area of the stent wall on three sides. The functional elements 28 have a droplet shape here.
Another exemplary embodiment shown in FIG. 3 has two finger-shaped carrier structures 26′ arranged at opposite ends on a web 4 running in the longitudinal direction L in the tangential plane. The longitudinal direction k of the carrier structures 26′ runs perpendicular to the longitudinal direction L of the stent. The functional element 28′ in the droplet shape extends around the opposing carrier structures 26′ so that the functional element 28′ completely surrounds both carrier structures 26′ and, in addition, surrounds the nearest area of the web 4 running in the longitudinal direction to which the carrier structures 26′ are attached. This yields a particularly great extent of the functional element 28′ essentially in the longitudinal direction L of the stent.
By analogy with the functional element 28′, the droplet-shaped functional element 28 may also be extended in another exemplary embodiment to such an extent that it extends up to the respective web 5.
FIG. 4 shows another exemplary embodiment having a carrier structure 36 whereby the carrier structure 36 has essentially a Y shape in a longitudinal section. The carrier structure 36 is connected at the first finger-shaped end to a web 4 running in the longitudinal direction L. On the second end, the carrier structure 36 has two fingers 37 protruding away from one another at an acute angle. The functional element designed in a spherical or disk shape completely surrounds the second end of the carrier structure 36 having the fingers 37 protruding away from the basic mesh 3.
The exemplary embodiment illustrated in FIG. 5 has a carrier structure 46 which is designed on the first end that is connected to the web 5 of the stent. On the second end, protruding away from the basic mesh 3, the carrier structure 46 has fractal branches 47. The fractal branches are preferably provided in the plane of the stent wall. In other exemplary embodiments, branches may also be provided in a plane running radially with respect to the stent. The functional element 48 completely surrounds the second end of the carrier structure 46 with the fractal branches 47 in a droplet shape. This yields an especially tight anchoring of the functional element 48 on the carrier structure 46.
In another exemplary embodiment shown in FIG. 6, the carrier structure 56 has several fingers 57 arranged on the side of the second end, the length of the fingers in the longitudinal direction k being smaller in the direction of the second end of the carrier structure 56 so that essentially a tree structure is formed. The fingers 57 surround an area 59 of the carrier structure 56 representing the trunk, preferably around the entire circumference. By analogy with the previous exemplary embodiments, the functional element 58 surrounds the second end of the carrier structure 56 completely with the tree structure 57, 59.
In other exemplary embodiments, the carrier structure may have other shapes than those shown above on the second end, these shapes ensuring a good attachment of the functional element arranged on the second end and at least partially surrounding the carrier structure.
The exemplary embodiment shown in FIG. 7 has a finger-shaped carrier structure 66 by analogy with the structure shown in FIGS. 1a or 1b, which has a smaller thickness in the radial direction, based on the stent, then does the stent web 5. The functional element 68, which is essentially a disk shape, surrounds the carrier structure 66 on the second end, whereby the functional element 68 is arranged only on the top side of the carrier structure 66. This achieves the result that the total thickness of the element consisting of the carrier structure 66 and the functional element 68 is comparable to the thickness of the webs 4, 5 of the stent so that a large volume of the functional element 68 is achieved and a small influence of the flow of the liquids flowing in the container is also achieved.
On the whole, the stent may have the carrier structures with functional elements illustrated in FIGS. 1a through 6 distributed over the entire length, whereby approximately similarly shaped carrier structures and functional elements or differently shaped carrier structures and functional elements may be used. This exemplary variant is especially preferred when the functional elements contain pharmaceutically active substances. Such an exemplary embodiment is shown in FIG. 8. The functional elements 28 with the carrier structures 26 shown in FIG. 3 are arranged so the functional elements are distributed over the entire wall of the stent and opposite the meandering webs 5.
Alternatively, such carrier structures are arranged on the distal and/or proximal end of the endoprosthesis and especially preferably on a circumferential line.
All patents, patent applications and publications referenced herein are incorporated by reference herein in their entirety.
Patent Application
20080033531
