Fixation system for vascular implants

Abstract

The present invention relates to a fastening system for a vascular implant, comprising a number of fastening elements (4) in the form of threads and / or seams and / or knots (4a, 4b) formed from threads, said fastening elements being provided on the inner surface (i) of said vascular implant (1). The fastening system allows a secure coupling of a number of telescopically arranged vascular implants.

Description

[Technical field]

[0001] The present invention relates to a fastening system for a vascular implant and to a vascular implant equipped with a corresponding fastening system. [Background technology]

[0002] Today, many vascular diseases and vascular abnormalities can already be treated minimally invasively by the insertion of vascular implants. Depending on the vascular condition and the type of disease or abnormality to be treated, the recipient is provided with different types of vascular implants.

[0003] Aneurysms are one of the most frequent pathologies in the human vascular system. An aneurysm is a bulge in a partially weakened blood vessel wall. Constant pressure on the weakened vessel wall can cause the aneurysm to expand and eventually rupture, causing severe internal bleeding.

[0004] Aneurysms can in principle occur in any part of the vascular system, however, at certain points in the vascular system, the formation of aneurysms is expected due to vascular anatomy, such as branching points of blood vessels, so-called bifurcations.

[0005] Aneurysms become problematic, for example, when they compress another blood vessel or organ, which can cause pain and / or undersupply to other body areas and organs, such as the brain, resulting in more or less severe neurological disorders.

[0006] In particular, when an aneurysm is present in the brain or in a large blood vessel that carries a large amount of blood, the aneurysm may rupture, which may be dangerous for the patient. In the brain, the rupture of an aneurysm may cause cerebral hemorrhage, which may lead to mild to severe neurological disorders. In the most severe cases, such cerebral hemorrhage may result in the death of the patient.

[0007] When an aneurysm ruptures in a large blood vessel, such as an abdominal or thoracic aneurysm, fatal blood loss can occur in a very short period of time.

[0008] Until a few years ago, most aneurysms had to be treated surgically. In recent years, there has been a considerable expansion of alternative treatment options and medical devices for minimally invasive and endovascular treatment of aneurysms.

[0009] One of the preferred minimally invasive endovascular treatment options for aneurysms is the insertion of a vascular implant in the form of a vascular prosthesis or stent graft. A vascular prosthesis or stent graft is a form of vascular implant that consists of a stent support structure and a membranous covering that are combined to form a tubular implant, also called a covered implant or covered stent.

[0010] For the treatment of aneurysms, such covered implants bridge the aneurysmal region by connecting the robust regions of the blood vessel proximal and distal to the aneurysm, and allowing blood to flow correspondingly through the implant in the aneurysmal region. Since blood flow no longer flows through the aneurysm, on the one hand, rupture of the aneurysm is prevented, and on the other hand, the pressure exerted by the aneurysm on other tissues is substantially eliminated.

[0011] In order not to block the blood supply to collateral vessels in the region of the covered implant, it is necessary to supply the collateral vessels with blood, for example via the outlet of the covered implant. In the prior art, a number of techniques are known which provide a solution for this. Today, among other things, custom-made or modular vascular prostheses have become established, which are in each case adapted to the individual needs of the patient. Such custom-made and modular systems are expensive.

[0012] Special customizations have to be individually and mainly manually manufactured, which is time-consuming. Emergency interventions are therefore not possible. Both modular and custom implant systems are joined in the patient's own vascular system by the surgeon during the intervention.

[0013] A disadvantage of corresponding implants with prefabricated branches is their high space requirement in the unexpanded state, which makes placement by catheter difficult, especially due to increased friction. Generally, large-caliber catheters are required for placement of such implants.

[0014] Alternative implants, which have become known in the meantime and which are referred to hereinafter in particular as so-called multi-lumen implants, are conceptually significantly different from the implants described so far and which are referred to hereinafter as conventional implants, which attempt to more or less accurately reproduce the anatomical structure of the damaged vascular site in order to cover the area to be treated or to bridge an aneurysm. Such implants are therefore either individually manufactured or modularly assembled, as mentioned at the outset.

[0015] In contrast, a multi-lumen implant is essentially a type of distributor insert with one proximal opening and usually multiple distal branches or branches that are placed proximally to the aneurysm and whose distal branches can then be individually coupled via covered stents to blood vessels distal to the multi-lumen implant.

[0016] Such a multi-lumen implant is described, for example, in US Pat. No. 5,399,323.

[0017] The multi-lumen implant comprises a substantially tubular element and an element for fixing the proximal region of the tubular element in the blood vessel. The distal section of the multi-lumen implant preferably branches into at least two cavities. The multi-lumen implant may therefore be considered as a glove, with the distal cavities corresponding to the open terminating fingers.

[0018] Distal means the part of the structure that is located in the direction of blood flow and thus the end of the implant, and correspondingly proximal means the part that is located against the direction of blood flow and thus the beginning of the implant. Further information regarding the position definition can be seen from the drawings.

[0019] The conventional implants described and multi-lumen implants have in common that they usually have several elements (usually various covered implants, also called stent grafts) that must be joined and fixed to each other within the vascular system.

[0020] What these known implants or implant systems have in common is that they include a proximal main element, which may typically be a multi-lumen implant, and a secondary element, which is typically a stent graft, connected distally and / or laterally to the main element.

[0021] In this case, it is important for the permanent safety of the entire implant that the individual elements are reliably fixed in contact with one another or nested within one another.

[0022] Fixation of the individual elements is usually performed in a telescopic manner, by inserting the proximal section of the distal element into the distal section of the proximal element, at least the proximal section of the distal element is then significantly spread apart so that it couples force- or frictionally to the proximal element.

[0023] Regularly, the distal section of the proximal element can be shaped to provide a special connection point that allows for the most effective possible coupling: this section can thus be provided, for example, with a distal reduction, a distal reinforcement or a combination thereof, which allows for a stationary attachment of the element introduced therein.

[0024] In this case, it has been found that, despite the presence of special connections, there is still a risk of displacement occurring if the introduced elements become unfastened, shift or, in the worst case, slip out of the connection.

[0025] A further disadvantage of known connection points, particularly in the form of reinforcements, which usually include stent-like elements or rings, is that these reinforcements increase the volume of the corresponding implant and its diameter in the compressed state precisely for delivery through a catheter, making the compressed implant stiff.

[0026] On the one hand, this necessitates the use of large-caliber delivery catheters for delivery of the implant, and on the other hand, the stiffness of the implant impairs maneuverability within the vasculature. [Prior art documents] [Patent documents]

[0027] [Patent Document 1] International Publication No. 2019 / 219728 Summary of the Invention [Problem to be solved by the invention]

[0028] It is therefore an object of the present invention to provide a fixing element for vascular implants, in particular for covered vascular implants, such as vascular prostheses, covered stents and multi-lumen implants, which does not have the above-mentioned disadvantages and allows improved retention of the distal and proximal sections within such systems. [Means for solving the problem]

[0029] This problem is solved according to the invention with the features of claim 1. Advantageous configurations are the subject of the respective dependent claims. It should be noted that the features individually recited in the individual claims can also be combined with one another in any technically expedient manner, which represents further configurations of the invention.

[0030] The fixation system for the vascular implant according to the invention comprises a plurality of fixation elements in the form of threads and / or seams formed from threads and / or nodes formed from threads, which fixation elements are at least partially provided on the inner surface of the vascular implant.

[0031] The lumen of the vascular implant refers to the cavity of the vascular implant that is surrounded by the membrane or stent support structure. The inner surface of the vascular implant refers to the side of the vascular implant that defines the lumen. Thus, seams and / or nodes that are substantially located on the inner surface of the vascular implant are typically located on the inner surface of the membrane or the inner surface of the stent support.

[0032] The term "yarn" according to the invention refers not only to spun and twisted yarns, but also to filaments and fibers in the broad sense. The material of the yarn according to the invention is also not limited by the concept, i.e. it can be a natural or artificial material. The yarn can be a monofilament, i.e. a yarn consisting of only one fiber, or a polyfilament, i.e. a yarn consisting of several fibers (e.g. knitted fibers, etc.).

[0033] The threads also do not have to consist of fibers and can in principle be fine wires or metallic mesh wires.

[0034] For threads according to the present invention, it is important that the threads have the desired properties, such as breaking strength and biocompatibility, to provide a secure and durable bond.

[0035] Preferably, the seam has a loop which reaches into the interior of the vascular implant, thereby forming a particularly advantageous connection point for another vascular implant which is introduced therein.

[0036] The nodes, seams and threads may be arranged symmetrically, for example in rings, helices, spirals or helices, but may also be randomly distributed. The nodes, seams and threads arranged in rings may be arranged in several planes, i.e., in several rings located above and below each other, or only in one plane.

[0037] Such a ring comprises at least 3 nodes, but preferably 4 to 16, in particular 6 to 8 nodes, which are preferably arranged in a hexagonal shape in a regular hexagon or in an octagonal shape in a regular octagon.

[0038] Preferably, at least some of the nodes are connected to one another by threads, which threads extend through the cavity of the vascular implant and are not regularly fixed in position along the membrane or stent support structure, as is the case for example with seams, i.e. the threads preferably extend freely through the cavity of the vascular implant from one node to the other.

[0039] The thread extending between the nodes is preferably tensioned and does not form a loop, thus forming an additional fixation point for another vascular implant introduced in this area, but the tensioned arrangement does not prevent the introduction of another vascular implant, since it only reduces the opening of the cavity to a limited extent.

[0040] Preferably, each adjacent node is connected by a thread, so that the thread together with the nodes between which it extends and the sections of the vascular implant that correspond to them form an arc in which the thread forms a chord or, as the case may be, a side of the resulting polygon, i.e., for example, a hexagon or octagon.

[0041] The connections between the nodes may accordingly be restricted to one plane in each case or may additionally or alternatively take place between a number of planes, either once or multiple times, for example alternating in a zigzag manner.

[0042] In particular, the fixation system according to the invention is suitable for combination with a multi-lumen implant, as known, for example, from WO 2019 / 219728, in which case the fixation system according to the invention can be provided, inter alia, at the distal end of the distal branch of the implant.

[0043] Even though the fixation system according to the invention is substantially described below on the example of a multi-lumen implant, this fixation system is generally suitable for vascular implants and in particular for covered vascular implants.

[0044] Known multi-lumen implants comprise a substantially tubular element and a fixing element in the form of a stent or a clamping ring for fixing the tubular element in the blood vessel.

[0045] The tubular element is divided into a proximal and a distal segment, the distal segment bifurcating into at least two cavities.

[0046] The tubular element is positioned proximal to the aneurysm within the target vessel by one or more positional fixation elements. The tubular element may be attached to the one or more positional fixation elements by other techniques, such as clamping, welding, gluing, suturing, or other known techniques. The positional fixation elements are provided on a proximal section of the tubular element.

[0047] The distal section of the tubular element preferably divides into at least two branches, where the number of branches or branches is arbitrary and can be adjusted, for example, depending on the number of blood vessels to be treated. Preferred are embodiments with 2 to 5 branches.

[0048] The distal branch of the implant is usually connected to the blood vessel distal to the implant via a covered stent, a so-called stent graft, which bridges the aneurysmal region and effectively blocks blood flow to the aneurysm, relieving the aneurysm of stress, while at the same time allowing the distal vessel to receive the desired blood supply via the stent graft.

[0049] In order to improve the fixation of the stent graft, in the distal region of the implant, at least some of the branches can be provided with a fixation system according to the invention, which is preferably provided in the membrane of the implant.

[0050] In this case, for example, a substantial part of the threads forming the nodes and / or seams is provided on the inner surface of the branch, i.e. within the cavity of the branch, and this also applies correspondingly to loops that can be formed by the threads of the seam.

[0051] The possible arrangements and combinations of the fixing elements correspond to the basic disclosure of the present invention.

[0052] Fixation systems according to the present invention may be provided in addition to or may include existing elements such as, for example, nitinol rings, stent structures, or similar devices.

[0053] The fixation system according to the invention has the advantage over the prior art that the fixation elements made from threads are significantly more flexible than known stent-like fixation elements and thus form stable, load-bearing and reliable fixation points for further vascular implants.

[0054] Furthermore, the anchoring system according to the invention, consisting of anchoring elements formed by threads, can be compressed significantly better than known stent-like anchoring elements, so that the maneuverability of the vascular implant in the delivery catheter is not felt to be impaired and the use of a larger caliber delivery catheter is not necessary, since the anchoring system according to the invention does not result in excessively large diameters or stiffness of the compressed vascular implant.

[0055] The present invention and related technologies will be described in detail below with reference to the drawings. Please note that the drawings show a particularly preferred embodiment of the present invention. However, the present invention is not limited to the illustrated embodiment. In particular, the present invention includes any combination of technical features described in the claims or described in the specification as being related to the present invention, as long as it is technically significant. [Brief description of the drawings]

[0056] [Figure 1] FIG. 1 shows a first embodiment of a fastening element in the form of a ring or spiral seam. [Diagram 2] FIG. 2 shows a second embodiment of a fixation element in the form of nodes arranged in a ring or spiral. [Diagram 3] FIG. 3 shows a third embodiment of a fastening element in the form of a combination of ring-shaped or spiral seams and nodes. [Figure 4] FIG. 2 shows a combination of a fixation element according to the invention with a known reinforcement body consisting of a Nitinol ring. [Diagram 5] 3 shows another combination of a fixation element according to the invention with a known reinforcement body consisting of stent segments; FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0057] Figure 1 shows in view A a first embodiment of a fastening system according to the invention, which comprises a fastening element 4 in the form of a ring-like or spirally arranged seam 4a, which is connected to a multi-lumen implant 1, only diagrammatically shown, with a main lumen 2 and two accessory lumen 3. The fastening system 4 may consist of a single circumferentially extending seam 4a, for example provided as an edge at the proximal end of the accessory lumen 3.

[0058] The fixation system is of course suitable for many vascular implants, in particular for coated vascular implants.

[0059] The seam 4a partially thickens and at the same time stabilizes the membrane 3a, as shown in FIG. C. The seam 4a, which is provided as a ring-shaped or spiral thickening, forms a fixing point for fixing the position of an optionally inserted further vascular implant (not shown), so that the possibility of dislocation or slipping off of the further vascular implant is significantly reduced compared to the case where no corresponding fixing element 4 is provided.

[0060] Preferably, the seam 4a is provided in such a way that the section of the seam 4a located on the inner surface i of the membrane 3a at least partially comprises a loop 5 forming an additional fixing point for the inserted vascular implant, as shown in FIG. B. The opening of the loop 5 may be arranged at various angles, for example perpendicular or parallel to the opening of the vascular implant 1 or of the sublumen 3.

[0061] FIG. 2 shows a second embodiment of a fixation system according to the invention, which comprises fixation elements 4 in the form of nodes 4b arranged in a ring or spiral, which are connected to a multi-lumen implant 1 with a main lumen 2 and two accessory lumen 3, again shown only diagrammatically.

[0062] The nodes 4b essentially form individual thickened sections arranged on the inner surface i of the membrane 3a, as shown in figures B and C, and form anchoring points for an inserted vascular implant (not shown).

[0063] The nodes 4b can be arranged in a ring as shown in FIG. A1, or in a spiral as shown in FIG. A2.

[0064] Besides these two configurations, of course, various other symmetrical or random configuration patterns are also contemplated, which may possibly be tailored to the structure of the vascular implant to be inserted.

[0065] 3 shows a third embodiment of a fixation system according to the invention, which comprises fixation elements 4 in the form of nodes 4b arranged in a ring or spiral. The nodes 4b may be arranged in several planes, for example a node 4b forming a first plane or a first ring and another node 4b forming a second plane or a second ring. Preferably, adjacent nodes 4b are connected by threads 4c each protruding into the lumen of the accessory lumen 3.

[0066] The fixation element 4 is shown, for example, connected to a multi-lumen implant 1 with a main lumen 2 and two accessory lumen 3, again shown only diagrammatically.

[0067] The thread 4c protruding into the cavity is preferably tensioned between the nodes 4a, 4b and thus forms together with the nodes 4a, 4b a substantial fixation element 4. In contrast to a loose tension forming a loop as shown for example in Fig. 1B, the tensioned tension has the advantage in this third embodiment that a further introduced vascular implant (not shown) is not entangled with the thread 4c which would otherwise wind up in the bloodstream in a possibly uncontrolled manner.

[0068] Preferably, this third embodiment has an arrangement of at least three nodes 4b connected to each other by three threads 4c, as shown in Figure B2. Multiple nodes 4b and threads 4c in multiple planes are also contemplated, as shown in Figures B1, B3 and C. Preferably, the nodes 4b are arranged in a hexagon or octagon in a ring.

[0069] Furthermore, embodiments are also conceivable in which not all nodes 4a, 4b are connected to one another by threads 4c, but only in pairs, as shown, for example, in Figures B4 and B5, in which case the embodiment of Figure B5 has fixing elements in multiple planes, similar to the embodiment of Figure B1.

[0070] It is important to distinguish this third embodiment from the embodiment with seams, as shown for example in Fig. 1, that the fixing element 4 according to the third embodiment does not form a loose loop, but the thread 4c penetrates into the lumen i of the multi-lumen implant 1 so as to form a support for another vascular implant. The thread 4c, together with the nodes 4b between which it extends and the corresponding sections of the sublumen 3, forms a corresponding arc bo, as illustrated in Fig. B4. The thread 4c in this case forms the chord of the arc, in other words the side of the possibly resulting polygon, for example a hexagon, as shown in Fig. B3.

[0071] It will be clear to those skilled in the art that this third embodiment also does not have to follow the example of a rather symmetrical arrangement and that again the nodes 4b and the resulting threads 4c may be asymmetrically arranged, which may result in an asymmetrical polygon.

[0072] Furthermore, it is obvious to those skilled in the art that combinations of the three above-mentioned embodiments according to Figs. 1 to 3 are possible.

[0073] 4 shows a first possibility of combining the fixation system according to the invention with the fixation element 4 with a reinforcement consisting of a Nitinol ring 6, which is known for vascular implants such as the multi-lumen implant 1. In this case, the fixation element 4 in the form of a node 4b constitutes a fixing point on the inner surface i of the membrane 3a and can at the same time serve as a connection point between the membrane 3a and the Nitinol ring 6. The Nitinol ring 6 can additionally or alternatively be completely or partially enclosed in the membrane 3a, in which case the distal part of the membrane 3a is wrapped around one or more Nitinol rings 6, preferably inwards or outwards. In such a case, the node 4b can also serve to fix the wrapped membrane 3a in place.

[0074] Corresponding embodiments are possible with single or multiple Nitinol rings 6 in one plane and in multiple planes. Also contemplated are embodiments with a combination of multiple Nitinol rings 6, where the individual rings 6 have different diameters, such that the accessory lumen 3 tapers, for example, distally.

[0075] The nodes 4b increase the roughness of the inner membrane surface i, preventing or making more difficult the dislocation, and in particular the slippage, of an optionally introduced vascular implant (not shown).

[0076] The nodes 4b further serve as additional position fixing points for the Nitinol ring 6 or membrane 3a and therefore also serve for additional security.

[0077] The attachment of the nodes 4b may be performed symmetrically or asymmetrically.

[0078] The embodiment of FIG. 4 can also be combined with further fastening elements 4 according to FIGS.

[0079] FIG. 5, similar to FIG. 4, shows another possibility of coupling the fixation system according to the invention to a reinforcement consisting of stent segments 7 as known in vascular implants such as the multilumen implant 1 .

[0080] In this case, the fixing elements 4, in the form of nodes 4b, constitute fixing points on the inner surface i of the membrane 3a and can at the same time serve as connection points between the membrane 3a and the stent segments 7. The stent segments 7 can additionally or alternatively be completely or partially enclosed in the membrane 3a, in which case the distal parts of the membrane 3a are wrapped around the stent segments 7, preferably inwards or outwards. In such a case, the nodes 4b can also serve to fix the wrapped membrane 3a in place.

[0081] Corresponding embodiments are possible including a single row of stent segments 7 as shown in FIG. A1 or multiple rows of stent segments 7 as shown in FIG. A2.

[0082] The nodes 4b increase the roughness of the inner membrane surface i, preventing or making more difficult the dislocation of the optionally introduced vascular implant, in particular its slippage.

[0083] The nodes 4b further serve as additional position fixing points for the stent segments 7 or membranes 3a and therefore also serve for additional security.

[0084] The attachment of the nodes 4b may be performed symmetrically or asymmetrically.

[0085] The embodiment of FIG. 5 can also be combined with further fastening elements 4 according to FIGS.

[0086] A person skilled in the art is familiar with a number of different vascular implants. It is therefore clear to the person skilled in the art that the fixation system according to the invention is suitable for a number of vascular implants, in particular for covered vascular implants. This applies in particular to the area of ​​the vascular implant where another vascular implant is to be introduced and fixed. Usually this is the distal area. [Explanation of symbols]

[0087] 1. Multi-lumen implant 2 Main cavity 3 Sublumen (3a: membrane) 4 Fixation elements (4a: seam, 4b: node, 4c: thread) 5. Loop 6 Nitinol Rings 7 Stent Segment bo bow shape i inside a. External p Proximal d. Distal

Claims

1. A fastening system for a vascular implant, comprising a plurality of fastening elements (4) in the form of threads and / or seams and / or knots (4a, 4b) formed from threads, said fastening elements being at least partially provided on an inner surface (i) of said vascular implant (1).

2. 2. The fixation system for vascular implants according to claim 1, characterized in that the fixation elements (4) are arranged in a ring-like and / or spiral manner.

3. 2. A fastening system for a vascular implant according to claim 1, characterized in that the seam (4a) has a loop (5) that reaches into the cavity of the vascular implant (1).

4. 2. A fastening system for a vascular implant according to claim 1, characterized in that the nodes (4b) arranged in a ring form a polygon, in particular a hexagon or an octagon.

5. 2. A fastening system for a vascular implant according to claim 1, characterized in that at least some of the nodes (4a, 4b) are connected to one another by threads (4c).

6. 6. The fixation system for a vascular implant according to claim 5, characterized in that the threads (4c) together with the nodes (4a, 4b) between which they extend and the corresponding sections of the vascular implant (1) form an arc (bo) in which the threads (4c) extend through the lumen of the vascular implant (1) so as to form a chord.

7. A vascular implant comprising a fixation system (4) according to any one of claims 1 to 6.

8. 8. The vascular implant according to claim 7, wherein the vascular implant is a vascular implant covered by a membrane (3a).

9. 9. The vascular implant according to claim 8, wherein the covered vascular implant is a multi-lumen implant with a main lumen (2) and at least two sub-lumens (3), and the fixation system (4) is arranged in a distal region of at least one of the sub-lumens (3).

10. 9. Vascular implant according to claim 8, wherein the fixation system (4) is provided on the membrane (3a).

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