Multi-stent with membrane

Abstract

The present invention relates to a multiple stent having at least two stents (1, 3) arranged coaxially and at least one membrane (2, 4), wherein a first stent (1) is configured as an internal stent and a second stent as an external stent, the first membrane (2) is arranged on the internal surface of the first stent (1) and / or the second membrane is arranged on the external surface of the second stent (3), and each membrane end (2A, 2B; 4A, 4B) is folded back around the respective end of the stent (1, 3) on which it is arranged, thereby clamping the membrane end (2A, 2B; 4A, 4B) between the two stents (1, 3).

Description

[Technical field]

[0001] The present invention relates to a multiple stent having at least two stents arranged coaxially and at least one membrane, the ends of which are fixed between the two stents. Multiple stents are used in particular as stent grafts for bypassing vascular malformations, such as aneurysms or shunts, but also for reinforcing unstable, brittle or thrombosed vessel walls. Multiple stents are further used to reconnect vessels branching from the stented vessel. [Background technology]

[0002] Stent grafts for bypassing vascular malformations are known in many forms. Typically, a stent graft consists of a stent that is completely or partially covered by a membrane. The membrane confines the vascular malformation to the blood vessel, and the stent holds the vessel open so that the membrane fits closely to the vessel wall.

[0003] The problem with such known stent grafts is the reliable fixation of the membrane to the stent. For example, suturing the membrane to the stent framework is fundamentally very reliable and durable, but is also very time-consuming and correspondingly expensive. In an alternative development, the membrane is fixed to specific clip-like holding elements of the stent.

[0004] Another development in this field concerns stent grafts in the form of so-called double stents, in which a membrane is held between two radially arranged stents, an outer stent and an inner stent, when such a double stent is expanded, the membrane is involved in the radial expansion and remains sandwiched between the two stents.

[0005] Such a double stent is known, for example, from US Pat. No. 5,399,323. This known double stent, as explained above, is provided with a separate material layer or membrane which is held between the two stents.

[0006] An alternative double stent is described in US Pat. No. 5,399,633, in which a second membrane is arranged on the outer stent, the membrane ends of the first membrane as well as the membrane ends of the second membrane meeting at the ends of the stent, folded back on the inner surface of the inner stent and fastened firmly under flexible tongues of the inner stent.

[0007] Although the known double stents are basically functional, there are several areas in which they could be improved.

[0008] For example, the layer of material placed between the two stents of the first described double stent is subjected to friction between the inner and outer stents during expansion, which friction can cause damage to the layer of material. If these damages cause holes or tears in the layer of material, either immediately or after some time of use, leakage problems can occur. Thus, for example, closure of the vascular malformation can no longer take place.

[0009] Another known variant with two membranes has the particular disadvantage that the respective membrane ends must be clamped in a double layer in the flexible tongue in the lumen of the double stent, which not only imposes a lot of manual demands but also inevitably leads to considerable material accumulation and thus to bulges in the stent lumen due to the protruding clips and possibly due to the bulging membrane ends, which inevitably become starting points for the formation of thrombi, which can lead to occlusion of the stent.

[0010] A further drawback of known double stents is that the inner lumens are formed by the respective bare stents without any inner covering, the bare struts of the stents creating another target surface for plaque and thrombus formation which can cause turbulence in the blood flow and lead to occlusion of the stent. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] DE 19720115 A1 [Patent Document 2] DE 102016120445 A1 Summary of the Invention [Problem to be solved by the invention]

[0012] The problem underlying the present invention is therefore to provide an improved stent graft which does not have the above-mentioned disadvantages of the known double stents.

[0013] A further object of the present invention is to provide a stent graft that can be easily fabricated. [Means for solving the problem]

[0014] This problem is solved by a multiple stent of the type mentioned at the beginning, which has at least two coaxially arranged stents and at least one membrane, with a first stent on the inside and a second stent on the outside, the first membrane being arranged on the inside surface of the first stent and / or the second membrane being arranged on the outside surface of the second stent, and each membrane end is folded back around the respective end of the stent on which it is arranged, so that the membrane ends are clamped between the two stents.

[0015] Thus, in principle, an arrangement of multiple stents and membranes arranged thereon is conceivable, but an embodiment substantially as described below having two or three stents and one or two membranes has proven to be advantageous.

[0016] "Externally or externally" in the sense of the present invention is understood to mean that this part of the multiple stent is placed close to the vessel wall, whereas "internally" refers to the part of the multiple stent that is placed further away from the vessel wall and thus closer to the lumen of the multiple stent. More details on the spatial information can be taken from the drawings.

[0017] In a first preferred embodiment, a multiple stent according to the invention comprises an inner stent having a first end and a second end and an outer stent having a first end and a second end, the stents being arranged coaxially with each other.

[0018] In a first preferred embodiment, the multiple stent according to the present invention further comprises an inner membrane and an outer membrane, the inner membrane being disposed on the inner surface of the inner stent and the outer membrane being disposed on the outer surface of the outer stent.

[0019] The ends of the membrane are folded back around the ends of the stents on which they are disposed, such that each end of the membrane is sandwiched between the stents.

[0020] In a second preferred embodiment, a multiple stent according to the invention comprises an inner stent having a first end and a second end and an outer stent having a first end and a second end, the stents being arranged coaxially with each other.

[0021] In a second preferred embodiment, the multiple stent according to the present invention further comprises an inner membrane, which is disposed on the inner surface of the inner stent.

[0022] The ends of the inner membrane are folded back around the ends of the inner stent so that they are sandwiched between the stents.

[0023] In a third preferred embodiment, a multiple stent according to the invention comprises an inner stent having a first end and a second end and an outer stent having a first end and a second end, the stents being arranged coaxially with each other.

[0024] In a third preferred embodiment, the multiple stent according to the present invention further comprises an outer membrane, which is disposed on the outer surface of the outer stent.

[0025] The ends of the outer membrane are folded back around the ends of the outer stent so that they are sandwiched between the stents.

[0026] In one variation of the preferred described embodiment, each multiple stent has an additional third or middle stent disposed between the inner and outer stents.

[0027] The intermediate stent may be provided to stabilize the multiple stents, which may also or additionally be provided to further fix the membrane. To further fix the membrane, the intermediate stent may, for example, have a corresponding surface structure or be made of such a material that resists the displacement of the membrane. For the intermediate stent, surfaces and materials such as, for example, surfaces that are easily roughened to increase frictional forces are also correspondingly conceivable. These surfaces are not advantageous for the inner and outer stents, because they are in direct contact with the vessel wall or blood flow, at least in certain embodiments.

[0028] In an additional variant of the described embodiment, it is conceivable that certain stents of the multiple stent, and thus for example the inner stent and / or the middle stent and / or the outer stent, are not configured as a unitary or through stent body, but are composed of several possibly connected or unconnected stent elements (i.e. individual stent bodies), which in their entirety may correspond to the length of the multiple stent or to the length of the remaining stents of the multiple stent, but which may in their entirety be shorter and therefore have gaps with respect to the remaining stents, or may be longer and therefore form overlaps.

[0029] In the context of this additional variation, terms such as "inner stent" or "outer stent" may better be understood herein as "inner stent layer" or "outer stent layer," in the sense that this is a specific layer within a multi-layer stent, which may be comprised of an integral or continuous stent body, or alternatively of multiple stent elements that may be joined or not joined.

[0030] At least one stent of the multiple stent preferably comprises a through or connected stent body, which is preferably a membrane constructed stent.

[0031] The following description applies to all embodiments of the multiple stent according to the invention, and in particular to the preferred embodiment and the variants described.

[0032] For all membranes, all suitable biological or artificial materials can be used. Usually, the membrane is made of plastic, preferably a plastic tube, which is put on the respective stent. Suitable materials are, for example, polytetrafluoroethylene, PTFE, especially ePTFE, which have the necessary elasticity for expansion. Other medically suitable plastics, such as polyester, polyolefin, polyurethane, polyurethane carbonate, etc., can be used as well. Also, for example, knitted, woven or sewn membranes made of fibers, especially polymer fibers, are conceivable.

[0033] The length of the membranes can be selected such that their ends, after being folded back, overlap between the stents, and preferably in this case the membranes are 5% to 25%, more preferably 25% to 50%, even more preferably 50% to 75% and in particular 75% to 100% longer than the stents on which they are arranged.

[0034] However, embodiments are also envisaged in which the ends of at least one membrane overlap, ie the membrane is more than twice as long as the stent on which it is placed.

[0035] The membranes may be constructed from different materials and may have different lengths if multiple membranes are used in a multiple stent.

[0036] When multiple membranes are provided, the membranes may be of the same length or of different lengths, the membranes may be symmetrically arranged or in other configurations.

[0037] The stent may be configured to be balloon expandable or self-expandable. Correspondingly, the stent may be braided or cut by a laser beam from a tube of appropriate diameter. The stent may have a woven or lattice structure.

[0038] The basic approach according to the invention of multiple stents essentially results in a relatively large wall thickness of the construct, which may limit its maneuverability in the vasculature of the patient. This can be countered by choosing a small wall thickness of the tube used to cut the stent or a small diameter of the wire used to knit the stent, for example in the range of 0.05 mm to 0.50 mm, preferably 0.10 mm to 0.20 mm, in particular about 0.15 mm. The web width can also be reduced, for example to 0.05 mm to 0.50 mm, preferably 0.10 mm to 0.20 mm, in particular about 0.15 mm. By using at least two stents, high radial forces are achieved even with a small wall density or wire diameter.

[0039] Correspondingly, for the stent, customary materials come into consideration, such as medical steel, cobalt-chromium alloys and nickel-titanium alloys or any combination thereof. Plastics (polymers), such as absorbable plastics, among others the numerous polylactic acids known from the prior art, can also be used, as can combinations consisting of metal stents and plastic stents. The arrangement and material of the stent are selected by the skilled person according to the respective task. For example, the inner stent can comprise metal and the outer stent can comprise plastic, or vice versa. However, it is also possible that all the stents are made of the same material.

[0040] It is clear that the different stents may have different thicknesses and different lengths, and at least the inner and outer stents of a multiple stent according to the invention are preferably arranged symmetrically with respect to each other.

[0041] However, embodiments in which the stents are staggered or have different lengths are also conceivable, provided that the required clamping effect is still achieved.

[0042] Likewise, different designs of the stents can be used. For example, the more externally arranged or outer stent preferably has a finer mesh than the more internally arranged or inner stent. This creates compressive stresses during expansion, which advantageously affect the radial forces and the bonds of the construct. This results in a high stability and robustness of the construct.

[0043] The nominal diameter of the further inwardly placed stent or inner stent is at least as large as the nominal diameter of the further outwardly placed stent, which should preferably be selected to be slightly larger than the nominal diameter of the further outwardly placed stent in order to achieve a greater clamping effect.

[0044] Fixing the membrane ends between the stents by clamping provides a reliable fixation of the membrane and is easy to manufacture since it is not necessary to make and handle multiple small clamp elements or to perform tedious sewing.

[0045] In one development of the multiple stent according to the invention, the multiple stent is particularly suitable for use in a multi-lumen implant, which is understood to mean an implant that is adapted for implantation in the vascular system and has branches that are adapted to the vascular morphology of the patient. Typically, the multi-lumen implant is a multi-lumen stent graft.

[0046] Multi-lumen implants are often provided as kits, since the individual vascular morphology can vary greatly from patient to patient, and custom-making would be expensive and time-consuming. Correspondingly, during or before the intervention, the individual branches of the multi-lumen implant are selected to the respective diameter of the vessel to be treated. Critical here is the connection of the individual components, which should be reliably and easily produced.

[0047] In this development, correspondingly, at least one end or edge region of the multiple stent is provided with a retaining element, by means of which the multiple stent can be fixed to the multi-lumen implant. The retaining element can be configured, for example, in the form of a hook-shaped and radially outwardly oriented element. The hook-shaped and radially outwardly oriented elements can preferably be parts of the stent that are bare, i.e. not covered with a membrane.

[0048] As retaining elements, specific deformations of the stent ends or edge regions of the stents can also be used. For example, it is conceivable to extend outwards at least one end region of at least one stent that is part of the multi-stent. For this purpose, for example, the end struts of the stent can be specially shaped, in particular longer than the remaining struts, in order to facilitate such deformations.

[0049] It is also conceivable, in particular, for a hook-like retaining element to be provided on the covered stent and to be able to additionally fix the membrane at the turn-back point in addition to its retaining function in the multi-lumen implant, the retaining element being in any case arranged to protrude far enough from the multi-lumen stent in order to allow sufficient fixation in the multi-lumen implant.

[0050] For this purpose, for example, the end of the stent equipped with the retaining element may be somewhat long and thus may already protrude from the multiple stents, which is particularly advantageous when one of the inner stents is equipped with a retaining element.

[0051] If the outer stent is equipped with hook-like retaining elements, it is preferred, particularly in relation to the second described embodiment, that the uncovered outer stent is configured as a whole shorter than the inner covered stent, so that the outer stent is completely covered with respect to the vascular lumen by the inner stent or by a membrane arranged on said stent.

[0052] Other configurations of retention elements besides the hooks described above are contemplated, such as retention elements similar to a lock and key system or a hook and clasp system that are specifically adapted for corresponding extension points in a multi-lumen implant.

[0053] The combination of an inner stent with an outer membrane and / or an inner membrane and an outer stent results in a surprisingly stable implant, which nevertheless has high flexibility. The membrane and at least the double stent layer contribute to the stabilization of the multiple stent, which allows the stent wall to remain relatively thin. Nevertheless, the multiple stent has good radial strength.

[0054] The invention will now be described in more detail with reference to the accompanying drawings, in which preferred embodiments of the invention are shown, and it is clear that each of the features shown in the drawings is part of the invention in itself and should not be understood solely in relation to other features of the drawings. [Brief description of the drawings]

[0055] [Figure 1] 1 is a schematic diagram showing the structure of a first embodiment of a multiple stent according to the present invention; [Diagram 2]FIG. 2 shows detail B of FIG. 1 with a stent and membrane arrangement according to a first embodiment of a multiple stent according to the invention. [Diagram 3] FIG. 2 is a schematic diagram showing the structure of a second embodiment of a multiple stent according to the present invention. [Figure 4] FIG. 4 shows detail B of FIG. 3 with a stent and membrane arrangement according to a second embodiment of a multiple stent according to the invention. [Diagram 5] FIG. 2 is a schematic diagram showing the structure of a third embodiment of a multiple stent according to the present invention. [Figure 6] FIG. 6 shows detail B of FIG. 5 with a stent and membrane arrangement according to a third embodiment of a multiple stent according to the invention. [Figure 7] FIG. 1 illustrates the use of multiple stents according to the present invention in a multi-lumen implant. [Figure 8] FIG. 2 shows details of a development of a multiple stent according to the invention with a retaining element for use in a multilumen implant. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0056] In Fig. 1, a first embodiment of a multiple stent M according to the invention is shown, which has an inner stent 1 with a first end 1A and a second end 1B, and an outer stent 3 with a first end 3A and a second end 3B. Stents 1 and 3 are arranged coaxially with each other. The multiple stent M is shown in an unexpanded state. An inner membrane 2 is arranged on the inner surface of the inner stent 1, and an outer membrane 4 is arranged on the outer surface of the outer stent 3.

[0057] Membranes 2 and 4 are folded back around ends 1A, 1B, 3A and 3B of stents 1 and 3, respectively, so that the ends of membranes 2 and 4 are sandwiched between stents 1 and 3.

[0058] The stents 1 and 3 may be constructed to be balloon expandable or self-expandable and may be made of any known material. The stents 1 and 3 may be constructed from different materials. The nominal diameter of the inner stent 1 is at least as large as the nominal diameter of the outer stent 3, and should preferably be selected to be slightly larger than the nominal diameter of the outer stent 3 in order to achieve a greater clamping effect.

[0059] The membranes 2 and 4 can be made from a wide variety of known materials, with a hose-like membrane made of ePTFE being preferred. It is also possible for the membranes 2 and 4 to be made from different materials.

[0060] 2 shows a detail view B of FIG. 1 for arranging the stent 1, stent 3 and the membrane 2, 4 relative to each other. The two ends 2A, 2B, 4A, 4B of the inner membrane 2 and the outer membrane 4 are folded back around the ends 1A, 1B, 3A, 3B of the stent 1, 3, respectively, in the region between the stent 1 and the stent 3, where the inner membrane 2 and the outer membrane 4 abut the stent 1, stent 3 on the inside or outside. Thus, the ends 2A, 2B, 4A, 4B, or more precisely the end regions of the membrane 2, 4 are sandwiched between the two stents 1, 3. The membranes 2, 4 may have different lengths as shown, but they may also be configured to be the same length. The lengths of membranes 2 and 4 can be selected so that their respective ends 2A, 2B or 4A, 4B do not contact or overlap between stents 1 and 3 as shown, but the lengths of membranes 2 and 4 may also be selected so that their respective ends 2A, 2B or 4A, 4B do contact or overlap between stents 1 and 3.

[0061] In Fig. 3 a second embodiment of a multiple stent M according to the invention is shown, which has a first inner stent 1 with a first end 1A and a second end 1B and a second outer stent 3 with a first end 3A and a second end 3B. The stents 1 and 3 are arranged coaxially with each other. The multiple stent M is shown in the unexpanded state. In this embodiment only one membrane 2 is arranged on the inner surface of the inner stent 1.

[0062] The membrane 2 is folded back around the ends 1A, 1B of the inner stent 1 so that the ends of the membrane 2 are sandwiched between the stents 1 and 3.

[0063] The stents 1, 3 may be constructed to be balloon expandable or self-expandable and may be made of any known material. The stents 1, 3 may be constructed of different materials. The nominal diameter of the inner stent 1 is at least as large as the nominal diameter of the outer stent 3, and should preferably be selected to be slightly larger than the nominal diameter of the outer stent 3 in order to achieve a greater clamping effect.

[0064] The membrane 2 can be made from a wide variety of known materials, with a hose-like membrane made from ePTFE being preferred.

[0065] 4 shows a detail view B of FIG. 3 for arranging the stent 1, stent 3 and membrane 2 relative to each other. The two ends 2A, 2B of the inner membrane 2 are folded back around the ends 1A, 1B of the inner stent 1, respectively, in the area between the stent 1 and the stent 3. The ends 2A, 2B of the membrane 2 are thus sandwiched between the two stents 1 and 3. The length of the membrane 2 can be selected such that its ends 2A, 2B do not contact or overlap between the stent 1 and the stent 3 as shown, but the length of the membrane 2 may also be selected such that its ends 2A, 2B contact or overlap between the stent 1 and the stent 3.

[0066] In Fig. 5 a third embodiment of a multiple stent M according to the invention is shown, which has a first inner stent 1 with a first end 1A and a second end 1B and a second outer stent 3 with a first end 3A and a second end 3B. The stents 1 and 3 are arranged coaxially with each other. The multiple stent M is shown in the unexpanded state. In this embodiment only one membrane 4 is arranged on the outer surface of the outer stent 3.

[0067] The membrane 4 is folded back around the ends 3A, 3B of the outer stent 3 so that the ends of the membrane 4 are sandwiched between the two stents 1 and 3.

[0068] The stents 1 and 3 may be constructed to be balloon expandable or self-expandable and may be made of any known material. The stents 1 and 3 may be constructed of different materials.

[0069] The nominal diameter of the inner stent 1 is at least as large as the nominal diameter of the outer stent 3, and should preferably also be selected to be slightly larger than the nominal diameter of the outer stent 3 in order to achieve a greater clamping effect.

[0070] The membrane 4 can be made from a wide variety of known materials, with a hose-like membrane made from ePTFE being preferred.

[0071] 6 shows detail B of FIG. 5 for arranging the stent 1, stent 3 and membrane 4 relative to one another. The two ends 4A, 4B of the outer membrane 4 are folded back around the ends 3A, 3B of the outer stent 3, respectively, in the area between the stent 1 and the stent 3. Thus, the ends 4A, 4B of the membrane 4 are sandwiched between the two stents 1 and 3.

[0072] The length of membrane 4 can be selected so that its ends 4A, 4B do not contact or overlap between stent 1 and stent 3, as shown, but the length of membrane 4 may also be selected so that its ends 4A, 4B contact or overlap between stent 1 and stent 3.

[0073] FIG. 7 shows the use of a development of multiple stents M according to the invention in a multilumen implant ML, ie in a bifurcated stent graft.

[0074] FIG. 8 shows in detail the edge region of a development of a multiple stent M according to the invention for use in a multi-lumen implant ML according to FIG. 7. In this development, a retaining element 5 is arranged at at least one end of the multiple stent M, with which the multiple stent M can be fixed to the multi-lumen implant ML. The multi-lumen implant ML is often provided as a kit, the individual branches of the multi-lumen implant ML being selected for the respective diameter of the vessel to be treated. It is the connection of the individual components that is critical. For this purpose, in this development, the retaining elements 5 are preferably configured in the form of hook-shaped and radially outwardly oriented elements 5. These may preferably be part of the uncovered stent, since the ends of the covered stent are covered by a folded membrane. Piercing the membrane by the retaining elements would cause unnecessary material damage. However, it is also conceivable for the retaining elements 5 to be configured with a dual function, in that they are provided on the covered stent and, in addition to their retaining function in the multi-lumen implant ML, allow additional fixing of the membrane at the turn-over point. In any case the retaining element 5 must be arranged to protrude far enough from the multiple stents to allow sufficient fixation in the multi-lumen implant ML. [Explanation of symbols]

[0075] 1 Inner (first) stent (1A, 1B: ends of inner stent) 2 Inner (first) membrane (2A, 2B: ends of inner membrane) 3 Outer (second) stent (3A, 3B: ends of outer stent) 4 Outer (second) membrane (4A, 4B: ends of outer membrane) 5 Retention elements M Multiple Stent ML Multi-Lumen Implant

Claims

1. A multiple stent having at least two stents (1, 3) arranged coaxially and at least one membrane (2, 4), with a first stent (1) on the inside and a second stent (3) on the outside, the membranes being composed of a first membrane (2) and a second membrane (4), the first membrane (2) being arranged on the inner surface of the first stent (1), the second membrane (4) being arranged on the outer surface of the second stent (3), and the first A multiple stent, characterized in that the membrane ends (2A, 2B) of the membrane are folded back on the outer surface around the ends (1A, 1B) of the first stent, and the membrane ends (4A, 4B) of the second membrane (4) are folded back on the inner surface around the ends (3A, 3B) of the second stent (3), thereby the first and second membrane ends (2A, 2B; 4A, 4B) are clamped between the first stent (1) and the second stent (3).

2. A multiple stent having at least two stents (1, 3) arranged coaxially and at least one membrane (2, 4), with a first stent (1) on the inside and a second stent (3) on the outside, characterized in that the membrane is a single membrane (2), the membrane (2) is arranged on the inner surface of the first stent (1), and the membrane ends (2A, 2B) of the membrane are folded back on the outer surface around the ends (1A, 1B) of the first stent (1), thereby tightening the membrane ends (2A, 2B) between the first stent (1) and the second stent (3).

3. A multiple stent having at least two stents (1, 3) arranged coaxially and at least one membrane (2, 4), with a first stent (1) on the inside and a second stent (3) on the outside, the membranes being made of a first membrane (2) and a second membrane (4), and a third stent being arranged coaxially between the first stent and the second stent, the first membrane (2) being arranged on the inner surface of the first stent (1), and the second membrane (4) being arranged on the inner surface of the first stent (1), a first stent (1) having an end (1A, 1B) of the first stent (1) folded on the outer surface thereof, said first stent (1) having an end (1A, 1B) of the first stent (1), and sandwiched between said first stent (1) and said third stent; and a second stent (4A, 4B) of the second stent (1) having an end (3A, 3B) of the second stent (1) folded on the inner surface thereof, said second stent (1) having an end (3A, 3B) of the second stent (1), and sandwiched between said second stent (1) and said third stent.

4. A multiple stent as described in any one of claims 1 to 3, characterized in that the stent (1) arranged on the inside has a nominal diameter at least as large as the stent (3) arranged on the outside, and the stent (1) arranged on the inside preferably has a nominal diameter larger than the stent (3) arranged on the outside.

5. A multiple stent according to any one of claims 1 to 4, characterized in that at least one of the membranes (2, 4) is of tubular construction.

6. 6. A multiple stent according to claim 1, characterized in that at least one of the membranes (2, 4) is 5% to 25% longer, preferably 25% to 50% longer, more preferably 50% to 75%, and in particular 75% to 100% longer than the stent (1, 3) on which it is arranged.

7. 7. A multiple stent according to claim 1, wherein at least one of the membranes (2, 4) has a length greater than twice the length of the stent (1, 3) on which it is arranged, whereby the folded membrane ends (2A, 2B; 4A, 4B) overlap each other between the stents (1, 3).

8. A multiple stent according to any one of claims 1 to 7, wherein the membranes (2, 4) are made from sheets or can be constructed from fibres by knitting, woven or stitching.

9. 9. A multiple stent according to any one of the preceding claims, characterized in that at least one end of one stent of the multiple stent (M) is provided with a fixing element (5).

10. 10. A multiple stent according to claim 9, characterized in that the fixing element (5) is configured as an extension of at least one end region of at least one stent of the multiple stent (M).

11. 10. The multiple stent according to claim 9, wherein the fixing elements (5) are configured in a hook-like manner and oriented radially outwardly.

12. 12. A multiple stent according to any one of claims 1 to 11, characterized in that at least one stent of the multiple stent (M) comprises a plurality of individual stent elements.

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