Stent

Abstract

The invention relates to a stent for transluminal implantation into hollow organs, in particular into blood vessels, ureters, oesophagi, colon, duodenum or bile ducts, comprising a substantially tubular body which extends in an axial direction and can be changed from a compressed state wtih a first cross-sectional diameter to an expanded state with an enlarged second cross-sectional diameter. The stent comprises a plurality of cells which are defined by web-like edge elements formed by the tubular body, the edge elements comprising at least one support strut running annularly about the axial direction. The stent is characterised in that the support strut has at least one V-shaped support portion which comprises a web angle from 90° to 150° when the stent has the second cross-sectional diameter.

Description

Technical Field The present disclosure relates to a stent for transluminal implantation into hollow organs, in particular into blood vessels, ureters, esophagi, the colon, the duodenum or the biliary tract, comprising a substantially tubular body that extends along an axial direction and that can be converted from a compressed state having a first cross-sectional diameter into an expanded state having an enlarged second cross-sectional diameter. The stent comprises a plurality of cells that are defined by strut-like bordering elements formed by the tubular body. The bordering elements comprise at least one support strut revolving in a ring shape about the axial direction. Background Stents of this kind are used for the recanalization of pathologically altered hollow organs. In this respect, in the compressed state having the first cross-sectional diameter, the stents are brought via an introduction catheter to the position to be treated within the hollow organ where they are expanded by different measures to a diameter that corresponds to the diameter of the healthy hollow organ such that a supporting effect of the hollow organ, for example of a vessel wall, is achieved. After the expansion, the stent in particular has the second cross-sectional diameter. A reference herein to a patent document or any other matter identified as prior art, is not to be taken as an admission that the document or other matter was known or that the information it contains was part of the common general knowledge as at the priority date of any of the claims. 2020274853   16 Sep 2026 Summary It may be desirable to provide a stent that can generate as high a deployment force as possible, i.e. a force in the radial direction that, for example, presses against the wall of a blood vessel. It may be desirable to provide a stent of the initially mentioned kind such that as high as possible a deployment force is provided, in particular also when the stent is formed from relatively soft materials. There is disclosed herein a stent for transluminal implantation into hollow organs, in particular into blood vessels, ureters, esophagi, the colon, the duodenum or the biliary tract, comprising a substantially tubular body that extends along an axial direction and that can be converted from a compressed state having a first crosssectional diameter into an expanded state having an enlarged second crosssectional diameter, wherein the stent comprises a plurality of cells that are defined by strut-like bordering elements formed by the tubular body, wherein the bordering elements comprise at least one support strut revolving in a ring shape about the axial direction, wherein the support strut has at least one V-shaped support section that comprises a strut angle of 90° to 150° when the stent has the second cross-sectional diameter; a longitudinal connector is attached to the support strut in the region of the strut angle and connects the support strut to at least one further support strut, and the bordering elements at least regionally comprise a bioresorbable material that comprises zinc. According to an aspect, there is provided a stent for transluminal implantation into hollow organs, in particular into blood vessels, ureters, esophagi, the colon, the duodenum or the biliary tract, comprising a substantially tubular body that extends along an axial direction and that can be converted from a compressed state having a first cross-sectional diameter into an expanded state having an enlarged second cross-sectional diameter, wherein the stent comprises a plurality of cells which are 2020274853   16 Sep 2026 defined by strut-like bordering elements formed by the tubular body, wherein the bordering elements comprise at least one support strut revolving in a ring shape about the axial direction, and wherein a longitudinal connector is attached to the support strut and connects the support strut to at least one further support strut, wherein no longitudinal connectors are arranged within a predefined vessel branching areal region, and the bordering elements at least regionally comprise a bioresorbable material which comprises zinc. The V shape of the support section can be formed by two limbs. The limbs can be part of the bordering elements. It has been recognised that a high radial deployment force can also be generated by the relatively large strut angle of 90° to 150° if the stent is, for example, formed from materials having a rather lower tensile strength. In contrast to, for example, common coronary stents that have strut angles in the range between 60° and 80°, a number of advantages may be achieved, as will be explained in more detail in the following. The strut angle is in this respect in particular to be understood as the angle that is spanned or defined by the two limbs of the V-shaped support section. In this respect, unless otherwise specified herein, the strut angle is always determined when the stent is in the expanded state having the second cross-sectional diameter, wherein the second cross-sectional diameter typically defines the nominal diameter. The nominal diameter is the diameter that is permanently required during the regular use of the stent. The stent can generally be formed from said bordering elements, wherein the bordering elements can also be designated as stent struts that together form a lattice framework that in turn defines the tubular body of the stent. 2020274853   16 Sep 2026 The bordering elements in this respect preferably form a plurality of cells, wherein a respective cell comprises the respective bordering element bounding it and can be connected to further cells by means of further bordering elements. In accordance with a first advantageous embodiment, the strut angle has an angle of 90° to 140°, preferably of 100° to 130°. The strut angle can further preferably have an angle of 105° to 115°. The angular indications mentioned herein are to be understood such that said limits are each included. The strut angle can in particular amount to 110°. It has been found that a particularly high radial deployment force can be achieved in the range around 110°. It must be noted only for clarification that the above-mentioned strut angles again refer to the state when the stent is expanded to the second cross-sectional diameter. In the first cross-sectional diameter, in which the stent can be introduced reduced in size into the body, the angle of the V-shaped support section can be considerably smaller and can in particular even amount to 0° if the limbs extend in parallel. More specifically, the angle of the V-shaped support section can in particular be less than 30°, preferably less than 15°, in the compressed state having the first cross-sectional diameter. Due to the use of a bioresorbable material, the stent does not remain in the body for a unlimited time period or has to be surgically removed. Instead, the material dissolves in the body after a few months and is absorbed via natural metabolic processes and is completely eliminated. In this way, biocompatibility problems and the body's own defense reactions can be minimized which can lead to the reclosing of vessels (for example due to late arteriosclerosis or thrombus formation). Polymeric materials, for example poly-lactic acid (PLA) or poly-L-lactic acid (PLLA), are in particular known as bioresorbable materials. However, such 2020274853   16 Sep 2026 polymeric materials have a low mechanical stability such that a bioresorbable material having a zinc portion is preferably used. Due to the use of zinc or a zinc alloy, the radiopacity of the stent compared to PLA, PLLA, or magnesium alloys can also be considerably increased. The insertion of the stent under X-ray observation can hereby be considerably facilitated and separate X-ray markers are not necessarily required. Other known bioresorbable materials are magnesium and magnesium-containing alloys, as already indicated above. In the body, magnesium reacts adversely with the water contained in the body tissue while releasing energy to form magnesium hydroxide and hydrogen. The hydrogen is then present in gaseous form and can lead to life-threatening embolisms at a corresponding concentration in the bloodstream, for example. Stents composed of magnesium alloys are therefore typically provided with PLLA coatings in a complex and / or expensive manner to be able to control the degradation process. In addition, the mechanical properties are especially worse than those of zinc alloys with respect to the elongation at break. Pure zinc or a zinc alloy can in particular be used as the bioresorbable material. The zinc alloy can, for example, be produced by admixing silver (Ag) and / or titanium (Ti). The zinc alloy can preferably have 90.0 to 99.95 mass % zinc and 0.05 to 10.0 mass % silver. Likewise, 0.05 to 10.0 mass % titanium can be admixed to the zinc alloy. However, a portion of 0.9 to 4.0% by mass of silver and / or titanium is / are preferably used, wherein the zinc alloy is also composed of zinc. Only 3.0% by mass of silver and / or titanium is / are particularly preferably used in addition to zinc, in particular between 2.8 and 3.2% by mass. A combination of 3.0 mass % silver and 97 mass % zinc has been found to be advantageous with respect to the mechanical stability for the stents described herein. In accordance with a further advantageous embodiment, the bioresorbable material consists of zinc and silver, wherein the bioresorbable material includes 2020274853   16 Sep 2026 90.0 to 99.95 mass % zinc and 0.05 to 10.0 mass % silver. Accordingly, the bioresorbable material can consist solely of zinc and silver. Such an alloy is described in the European patent application with the application number EP 16 702 899.2. For example, the zinc alloys of zinc and silver and / or titanium mentioned herein can have a tensile strength of 180 to 210 MPa, preferably of t190 to 200 MPa. The tensile strength is in this respect lower than, for example, in a 316L stainless steel that is not bioresorbable and that has a tensile strength of approximately 586 MPa. A stent having a high radial deployment force can, however, nevertheless be provided by the strut angle selected as described herein. The zinc alloys mentioned herein can furthermore have an elongation at break in the range from 80 to 180%, for example from 80 to 100%, preferably in the range from 90 to 100%. The elongation at break indicates the percentage by which a material can be stretched until it breaks. This high value of the elongation at break for said zinc alloys enables considerably more flexible support struts of the stent than would, for example, be possible with the 316L stainless steel (elongation at break 35%) or with pure zinc (elongation at break 8%). It is hereby in particular made possible to implement the large strut angle and in particular also to achieve the large angular difference of the V-shaped support section between the state having a compressed first cross-sectional diameter and an expanded second cross-sectional diameter. It must be noted that the values for the elongation at break provided herein apply to the actually processed bioresorbable material of the stent. Prior to the actual processing, the bioresorbable material can, for example, be processed by extrusion and / or tube drawing, whereby the elongation at break (and also other material properties) can also be significantly changed compared to the pure alloy. 2020274853   16 Sep 2026 In accordance with a further advantageous embodiment, the support strut comprises a plurality of V-shaped support sections that each have strut angles in the aforementioned range such that a zigzag shape of the support strut at least 5 regionally results. A plurality of V-shaped support sections can therefore be arranged behind one another such that a zigzag shape of the support strut results. The "openings" of the V-shaped support sections defined by the limbs in this respect each alternately face in opposite directions. 10 The strut angles of the individual support sections can each be different, but can lie in one of the aforementioned ranges. Alternatively, at least some or all of the strut angles can be equal, wherein a deviation of up to 10%, preferably up to 5%, particularly preferably up to 3%, is considered equal in this respect. Due to the same or at least similar strut angles, a homogeneous design of the stent can be 15 achieved. The support strut can in particular be formed from 8, 12, or 16 V-shaped support sections, for example. In accordance with a further advantageous embodiment, a longitudinal connector is attached to the support strut in the region of the strut angle and connects the 20 support strut to at least one further support strut. The longitudinal connector can in particular be attached at the point at which the two limbs of the V-shaped support section meet one another. The strut angle is preferably determined without taking the longitudinal connector into account. 25 The longitudinal connector preferably extends at least substantially in parallel with the axial direction and thus preferably approximately at a right angle to the support strut. The longitudinal connector is in particular a bordering element, wherein two longitudinal connectors and the associated sections of the support struts span or define a cell. 2020274853   16 Sep 2026 The longitudinal connector can preferably have a position marker that is approximately circular or elliptical in plan view. The position marker can comprise or consist of a thickened portion of the bioresorbable material. The position marker can in particular enable a positioning of the stent on a catheter. The position marker is preferably arranged adjoining or adjacent to the support strut. Along the extent of the support strut about the axial direction, the strut angle can in each case be alternately disposed on a side of the support strut remote from the longitudinal connector and on a side of the support strut facing the longitudinal connector. If the strut angle is disposed on the side facing the longitudinal connector, the longitudinal connector can be disposed approximately at the center in the strut angle. In addition, a longitudinal connector can be attached only in the region of every second strut angle. Viewed along the peripheral direction of a support strut, the longitudinal connectors can be alternately attached at oppositely disposed sides of the support strut. In other words, more V-shaped support sections can be present per support strut than longitudinal connectors. Alternatively, exactly the same number of V-shaped support sections can be present as there are longitudinal connectors. A plurality of longitudinal connectors, in particular exactly two or three longitudinal connectors, can preferably be attached to each support strut at the same side. This means that two adjacent support struts are connected to one another by exactly two or three longitudinal connectors. Due to the connection to two or three longitudinal connectors, it is possible to flexibly form the stent such that it can be easily adapted to curvatures and curves of the hollow organ to be supported. At the same time, a high radial deployment force is provided by the support struts. 2020274853   16 Sep 2026 The stent can in particular have a middle part that consists solely of support struts and the longitudinal connectors connecting the support struts. The middle part is located between the two ends of the stent, viewed in the axial direction. In accordance with a further advantageous embodiment, the support strut at least substantially revolves radially about the axial direction such that the axial direction forms a normal vector to the plane defined by the support strut. For the determination of the plane defined by the support strut, a zigzag shape of the support strut is not taken into account, but is averaged out if necessary. In other words, the support strut is not arranged laterally, obliquely, or canted with respect to the axial direction. Instead, the axial direction is perpendicular to the plane defined by the support strut. The support struts consequently in particular also do not cross one another. All of the support struts are preferably arranged in this manner. In accordance with a further advantageous embodiment, the stent is expandable to a third cross-sectional diameter that is larger than the second cross-sectional diameter, with the strut angle increasing to at least 120°, preferably to at least 140° or 160°, when the stent has the third cross-sectional diameter. A strut angle of at least 165° or 170° can in particular also be present in the case of the third crosssectional diameter. The strut angle can also be at least 10° or 20° larger in the case of the third cross-sectional diameter than in the case of the second crosssectional diameter. For example, it can be necessary in the coronary region to temporarily enlarge the stent to the third cross-sectional diameter on the insertion of the stent, whereby the stent is then better embedded in the respective blood vessel and keeps a sufficiently dimensioned lumen free to ensure an unobstructed blood flow. The adhesion of blood platelets that could otherwise lead to thrombosis is hereby suppressed. 2020274853   16 Sep 2026 The third cross-sectional diameter can be at least 7 to 20% (e.g. 10% or 14%) larger than the second cross-sectional diameter. In particular due to the zinc alloy mentioned herein, the material of the stent can be so flexible that the mentioned strut angles in the case of the third cross-sectional diameter can also be achieved without a material breakage taking place. The maximum strut angle in the case of the third cross-sectional diameter can be 170°, preferably at most 150°. In accordance with a further advantageous embodiment, the stent is designed in the same manner except for the end regions in the axial direction. This means that the stent has the same design everywhere and can only deviate from this similar design at its ends, for example. The ends in the axial direction are understood as the ends at which a blood entry or exit, for example, takes place if the stent is inserted in a blood path without branching. Alternatively, it is also possible that the bordering elements have a smaller mass within a predefined vessel branching areal region than the bordering elements in another areal region of the same size, with the smaller mass, for example, being achieved by thinner bordering elements. The predefined vessel branching areal region is an area, in particular a curved area, that results when the stent is in the expanded state having the second cross-sectional diameter. The vessel branching areal region serves to be positioned at a vessel branching, wherein a dilation of the branch is then more easily possible due to the smaller mass in the region of the vessel branching areal region. Therefore, a cut-out can hereby be created in the region of the vessel branching areal region, said cut-out e.g. enabling an unobstructed blood flow for the vessel branching. To achieve the smaller mass, the mass per path length of the bordering elements can, for example, be at least 15%, preferably at least 25%, smaller than in the 2020274853   16 Sep 2026 case of the other bordering elements. Accordingly, the bordering elements and thus, for example, also a region of a support strut that extends through the vessel branching areal region can be thinner or narrower by 25%, for example. In accordance with a further advantageous embodiment, no longitudinal connectors are arranged within the vessel branching areal region. In other words, only support struts, e.g. with their V-shaped support sections, are provided within the vessel branching areal region. Due to the omission of the longitudinal connectors, the mass of the bordering elements is likewise smaller. A dilation of the branch is simplified even further in this manner, but the radial strength is still maintained. In accordance with a further advantageous embodiment, one or more X-ray markers are arranged within the vessel branching areal region and / or adjacent to the vessel branching areal region. The X-ray markers can have a radiopaque material, for example, tantalum. The radiopaque material can be held in an eyeletshaped structure of the bordering elements. Four X-ray markers can e.g. in particular be provided that are each arranged at uniform spacings at the boundary of the vessel branching areal region. Due to the X-ray markers arranged in this manner, the correct positioning of the stent or of the vessel branching areal region at a vessel branching under X-ray observation is considerably facilitated. In accordance with a further advantageous embodiment, the bordering elements are at least regionally provided with a medicine, wherein the medicine is preferably dispensed by the stent over a predetermined period of time. The medicine can have an anti-proliferative effect to prevent a tissue overgrowth of the stent. For example, anti-proliferatives of the Limus group, statins, P2Y12 antagonists, or thrombin antagonists can be used as the medicine. 2020274853   16 Sep 2026 In accordance with a further advantageous embodiment, the bordering elements have a wall thickness of at most 4%, preferably of at most 2%, further preferably of at most 1.5%, of the second cross-sectional diameter. The width of the bordering elements, i.e. the dimension viewed in the peripheral direction, can preferably have at most 4%, further preferably at most 2%, particularly preferably at most 1.7%, of the second cross-sectional diameter. The bordering elements can, for example, have a width of approximately 105 to 120 pm and a wall thickness of 90 to 115 pm. The stent can thus comprise bordering elements that are approximately 25 to 40% narrower and / or thinner than bordering elements of conventional bioresorbable stents composed of PLLA. Due to the particularly thin and narrow bordering elements, a risk of thrombosis is further prevented since the accumulation of blood platelets is made more difficult. The stent can in particular be a coronary stent whose second cross-sectional diameter, for example, amounts to at most 2 mm or 4 mm. There is also described herein a stent for transluminal implantation into hollow organs, in particular into blood vessels, ureters, esophagi, the colon, the duodenum or the biliary tract, comprising a substantially tubular body that extends along an axial direction and that can be converted from a compressed state having a first cross-sectional diameter into an expanded state having an enlarged second cross-sectional diameter. The stent comprises a plurality of cells that are defined by strut-like bordering elements formed by the tubular body. The bordering elements comprise at least one support strut revolving in a ring shape about the axial direction, wherein a longitudinal connector is attached to the support strut and connects the support strut to at least one further support strut. The stent is characterized in that no longitudinal connectors are arranged within a predefined vessel branching areal region. 2020274853   16 Sep 2026 Due to the omission of the longitudinal connectors, the mass of the bordering elements is smaller and a dilation of the branch is simplified, as already stated above. In other words, only support struts, for example having V-shaped support sections, are provided within the vessel branching areal region. The vessel branching areal region can in particular have the size of an artery or a vein that opens into a blood vessel supported by the stent in the region of the stent. In accordance with an embodiment, one or more X-ray markers or position markers are arranged within the vessel branching areal region and / or adjacent to the vessel branching areal region. In accordance with an embodiment, the bordering elements have a smaller mass within the predefined vessel branching areal region than the bordering elements in another areal region of the same size, with the smaller mass, for example, being achieved by thinner bordering elements. As regards the further disclosed stent, the statements made herein with respect to the initially mentioned stent apply accordingly, this in particular applies to advantages and preferred embodiments. 2020274853   16 Sep 2026 Brief Description of Drawings Embodiments of the disclosure will be described purely by way of example with reference to the drawings in the following. There are shown: 5 Fig. 1                an outside view of a stent in the expanded state; Fig. 2                an outside view of the stent of Fig. 1, wherein the stent is in an over-expanded state; 10 Fig. 3               the stent of Fig. 1 in a compressed state; and Fig. 4               a vessel branching areal region of the stent. Detailed Description 15 Fig. 1 shows a part section of a stent 10 in an expanded state having a second cross-sectional diameter that corresponds to the nominal diameter of the stent 10. The stent 10 comprises a tubular body 12 that extends along an axial direction A. The Figures show the stent 10 from a viewing direction perpendicular to the axial direction A. The stent 10 is formed by a plurality of bordering elements 14 that 20 overall form a grid-like structure. The stent 10 continues to extend to the left and to the right of the part section shown in Fig. 1. Some of the bordering elements 14 form support struts 16 revolving in a ring shape about the axial direction A. The support struts 16 comprise a plurality of V-25 shaped support sections 18 that are arranged behind one another such that the support struts 16 have a structure of zigzag shape in the peripheral direction. Each V-shaped support section 18 comprises two limbs 20 between which a strut angle 22 is defined. In the embodiment shown, the strut angle 22 approximately amounts to between 105° and 110°. 2020274853   16 Sep 2026 In the region of the strut angle 22, the support struts 16 are connected to one another by means of longitudinal connectors 24, wherein in each case only every second support section 18 is coupled to a longitudinal connector 24 in the peripheral direction. Viewed in the peripheral direction, the longitudinal connectors 24 are each alternately attached at oppositely disposed sides of the support strut 16. The zigzag shape of the support struts 16 is selected such that adjacent support struts 16 extend approximately in parallel, i.e. they are not offset from one another or rotated relative to one another. This means that the connection points of a respective two limbs 20 of different support struts 16 each extend approximately along a straight line, wherein the strut angles 22 are each arranged at the same side of the support struts 16 along the straight line. The stent 10 shown is formed from a bioresorbable material that has 97% zinc (Zn) and 3% silver (Ag). Due to the selection of this zinc alloy, the large strut angles 22 shown can be achieved without the risk of a fracture of the bordering elements 14. As shown in Fig. 2, it is even possible to temporarily bring the stent into an overexpanded state in which the cross-sectional diameter is at least 7 to 20% larger than the aforementioned second cross-sectional diameter. Such a state is shown in Fig. 2. As shown in Fig. 2, the strut angle 22 can amount to more than 120° in this state. In contrast, Fig. 3 shows the stent 10 in a compressed state having a first crosssectional diameter. In this state, the limbs 20 are approximately parallel such that the strut angle 20 does not exist or is approximately 0°. 2020274853   16 Sep 2026 Finally, Fig. 4 shows a different part section of the stent 10 than shown in Figs. 13. Fig. 4 shows a part section of the stent 10 having a vessel branching areal region 28 that is approximately circular in plan view. The support struts 16 are designed 25% thinner within the vessel branching areal region 28 than in the remainder of the stent 10. In addition, no longitudinal connectors 24 are arranged within the vessel branching areal region 28, which is indicated by (non-existent) longitudinal connectors 24 drawn as dashed lines. It is understood that the support struts 16, which extend through the vessel branching areal region 28, are coupled by longitudinal connectors 24 arranged outside the vessel branching areal region 28. They are not shown in Fig. 4. The omission of the longitudinal connectors 24 and the thinner design of the support struts 16 results in an easier dilatability of the stent in the region of the vessel branching areal region 28 such that the support struts 16 can be bent outwardly in the region of a vessel branching, i.e. they can be bent against the margin of the vessel branching areal region 28 in order, for example, to improve a blood flow through the vessel branching. In the region of the omitted longitudinal connectors 24, a total of four circular or elliptical position markers 26 are attached to the support struts 16. The position markers facilitate the positioning of the stent 10 on a catheter (not shown). Unless the context requires otherwise, where the terms “comprise”, “comprises”, “comprised” or “comprising” are used in this specification (including the claims) they are to be interpreted as specifying the presence of the stated features, integers, steps or components, but not precluding the presence of one or more other features, integers, steps or components, or group thereof. 2020274853   16 Sep 2026 10 10 12 14 16 18 20 22 24 26 28 A 15 Reference numeral list stent tubular body bordering element support strut V-shaped support section limb strut angle longitudinal connector position marker vessel branching areal region axial direction

Claims

1. A stent for transluminal implantation into hollow organs, in particular intoblood vessels, ureters, esophagi, the colon, the duodenum or the biliary tract, comprising a substantially tubular body that extends along an axial direction and that can be converted from a compressed state having a first cross-sectional diameter into an expanded state having an enlarged second cross-sectional diameter, wherein the stent comprises a plurality of cells which are defined by strutlike bordering elements formed by the tubular body, wherein the bordering elements comprise at least one support strut revolving in a ring shape about the axial direction, andwherein a longitudinal connector is attached to the support strut and connects the support strut to at least one further support strut, wherein no longitudinal connectors are arranged within a predefined vessel branching areal region, andthe bordering elements at least regionally comprise a bioresorbable material which comprises zinc.

2. A stent in accordance with claim 1, whereinone or more X-ray markers or position markers are arranged within the vessel branching areal region and / or adjacent to the vessel branching areal region.

3. A stent in accordance with claim 1 or claim 2, whereinthe bordering elements have a smaller mass within the predefined vessel branching areal region than the bordering elements in another areal region of the same size, with the smaller mass, for example, being achieved by thinner bordering elements.

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