Anchoring system for vascular implants

Abstract

The invention relates to an anchoring system for vascular implants, comprising a plurality of anchoring elements (4) in the form of threads and / or sutures and / or knots (4a, 4b) formed by threads that are provided on the interior (i) of the vascular implant (1). The anchoring system allows for a reliable interconnection of a number of telescoping vascular implants.

Description

[0001] Anchoring system for vascular implants

[0002] The invention relates to an anchoring system for vascular implants and to vascular implants equipped with corresponding anchoring systems.

[0003] Today, a wide variety of vascular diseases and anomalies can be treated minimally invasively through the insertion of vascular implants. Depending on the condition of the vessel being treated and the type of disease or anomaly, various types of vascular implants are available to the practitioner.

[0004] One of the most common pathologies of the human vascular system is aneurysm. Aneurysms are bulges in the partially weakened vessel wall. Due to the constant pressure exerted on the weakened vessel wall, the aneurysm expands and can eventually rupture, leading to severe internal bleeding.

[0005] In principle, aneurysms can develop in any part of the vascular system. However, certain locations within the vascular system are predisposed to aneurysm formation due to their vascular anatomy, such as vascular bifurcations.

[0006] Aneurysms can cause problems if, for example, they press on other blood vessels or organs. This can lead to pain and / or impaired blood supply to other parts of the body and organs. If the brain is affected, for example, more or less severe neurological deficits can result.

[0007] If an aneurysm ruptures, it is particularly dangerous for the patient if the aneurysm is located in the brain or on a large vessel carrying a large amount of blood. Ruptured aneurysms in the brain lead to cerebral hemorrhages, which can cause mild to severe neurological damage. In the worst case, such a cerebral hemorrhage can lead to the patient's death.

[0008] If an aneurysm ruptures in a large vessel, fatal blood loss can occur within a very short time, for example in the case of ruptures of abdominal artery aneurysms or thoracic aneurysms.

[0009] Just a few years ago, many aneurysms required open surgery. Today, a wide range of alternative treatment options and medical devices are available for minimally invasive and intravascular aneurysm treatment.

[0010] One of the preferred minimally invasive, intravascular treatment options for an aneurysm is the insertion of vascular implants in the form of vascular prostheses or stent grafts. A vascular prosthesis or stent graft is a type of vascular implant consisting of a stent framework and a membranous covering, which, when combined, creates a tube-like implant. These are also referred to as covered implants or covered stents.

[0011] To treat an aneurysm, such a covered implant is used to bridge the aneurysm area. The implant connects the healthy areas of the vessel proximal and distal to the aneurysm, allowing blood to flow through the implant in the aneurysm area. Since blood flow no longer flows through the aneurysm, rupture of the aneurysm is prevented, and the pressure exerted by the aneurysm on other structures is largely eliminated. In order to avoid cutting off the blood supply to the side vessels in the area of ​​the covered implant, it is necessary to supply these side vessels, for example, via branches of the covered implant. A variety of techniques are known in the state of the art that offer possible solutions for this. Custom-made or modular vascular prostheses, which are tailored to the needs of each individual patient, have become established today.Such custom-made and modular systems are expensive.

[0012] Custom-made devices, in particular, require time, as they usually have to be individually crafted by hand. Spontaneous interventions are therefore not possible. Modular systems, as well as custom-made implant systems, are assembled by the surgeon himself within the patient's vascular system during the intervention.

[0013] A disadvantage of such implants with prefabricated branches is their high space requirement in the non-expanded state, which complicates placement via a catheter, particularly due to increased friction. Large-caliber catheters are generally required for the placement of such implants.

[0014] Alternative implants that have since become available, so-called multi-lumen implants will be discussed in particular below, differ significantly in concept from the described implants, referred to below as conventional. Conventional implants attempt to replicate the anatomy of the damaged vascular region more or less precisely in order to line the area to be repaired or to bridge an aneurysm. Accordingly, these implants are either custom-made or assembled in a modular manner, as described above.

[0015] A multi-lumen implant, on the other hand, essentially represents a type of distributor insert with a proximal opening and usually several distal branches. The multi-lumen implant is inserted proximal to the aneurysm, and its distal branches can be individually connected to the vessels distal to the multi-lumen implant via covered stents.

[0016] Such a multi-lumen implant is described, for example, in WO 2019 / 219728 A1.

[0017] The multi-lumen implant essentially comprises a tubular element and an element for securing the proximal portion of the tubular element in a vessel. The distal portion of the multi-lumen implant preferably branches into at least two lumens. The multi-lumen implant can thus be imagined as being glove-like, with the distal lumens corresponding to open-ended fingers.

[0018] Distal refers to the part of a structure that lies in the direction of blood flow and thus represents the end of the implant; proximal refers to the part that lies against the direction of blood flow and thus represents the beginning of the implant. Further information on the location designations can also be found in the figures.

[0019] What the described conventional implants and the multi-lumen implants have in common is that they usually comprise several elements - usually various covered implants as well as stent grafts - which must be joined together in the vascular system and anchored to each other.

[0020] What these known implants or implant systems have in common is that they usually comprise a proximal main element, which can be a multi-lumen implant, and distal and / or laterally connected secondary elements, which are usually stent grafts.

[0021] For the long-term safety of the implant as a whole, it is crucial that the individual elements are securely attached to or within each other. The individual elements are typically attached telescopically, by inserting a proximal section of the distal element into a distal section of the proximal element. Subsequently, at least the proximal section of the distal element is expanded to such an extent that it forms a force-locking or frictional connection with the proximal element.

[0022] The distal sections of the proximal element can often be shaped into special connection points that enable the most effective connection possible. For example, these sections are provided with a distal taper, distal stiffeners, or combinations thereof, which allows for a secure fit of the elements inserted there.

[0023] It has been shown that, despite the presence of special connection points, dislocations can still occur if the inserted elements become loose, shift or, in the worst case, even slip out of the connection in the seat.

[0024] A further disadvantage of known connection points, particularly in the form of stiffeners, which usually comprise stent-like elements or rings, is that these stiffeners increase the volume of the corresponding implant and especially the diameter in the compressed state for delivery through a catheter and stiffen the compressed implant.

[0025] This means, on the one hand, that large-caliber delivery catheters must be used to deliver the implant, and, on the other hand, that the stiffness of the implant impairs maneuverability within the vascular system.

[0026] The object of the invention is therefore to provide anchoring elements for vascular implants, and in particular for covered vascular implants such as vascular prostheses, covered stents, and multi-lumen implants, which do not have the disadvantages described above and which enable improved retention of distal and proximal sections in such a system. This object is achieved by an invention having the features of claim 1. Advantageous embodiments are the subject of the dependent claims. It should be noted that the features listed individually in the claims can also be combined with one another in any technologically expedient manner, thus demonstrating further embodiments of the invention.

[0027] The anchoring system for vascular implants according to the invention comprises a plurality of anchoring elements in the form of threads and / or sutures formed from threads and / or knots formed from threads, which are provided at least partially on the inside of the vascular implant.

[0028] The inner lumen of the vascular graft refers to the lumen of the vascular graft enclosed by the membrane or stent framework. The inner side of the vascular graft refers to the side of the vascular graft adjacent to the inner lumen. Accordingly, the sutures and / or knots, which are primarily intended for the inner side of the vascular graft, are usually located on the inner side of the membrane or stent framework.

[0029] According to the invention, the term "thread" refers not only to yarns and threads, but also broadly to filaments and fibers. The material of a thread according to the invention is also not limited by this term; it can be natural or synthetic materials. The thread can be monofilament, i.e., made of a single fiber, or polyfilament, i.e., made of multiple fibers (e.g., braided fibers, etc.).

[0030] However, the thread does not have to be made of fibers; in principle, it can also be made of fine wires or wire mesh made of metal.

[0031] It is essential for the thread according to the invention that it exhibits the desired properties, such as tensile strength and biocompatibility, in order to provide a reliable and permanent connection point. Preferably, the sutures have loops that extend into the interior of the vascular implant, thus forming a particularly advantageous connection point for additional vascular implants inserted therein.

[0032] The knots, sutures, and threads can be arranged symmetrically, for example, in a ring-shaped, helical, spiral, or screw-shaped pattern, but can also be randomly distributed. The knots, sutures, and threads arranged in a ring-shaped pattern can be arranged in multiple planes, for example, in several superimposed rings, or in a single plane.

[0033] Such a ring comprises at least three nodes, but preferably 4 to 16 and in particular 6 to 8 nodes, which are preferably arranged hexagonally in an equilateral hexagon or octagonally in an equilateral octagon.

[0034] Preferably, at least some of the nodes are connected to each other by threads such that the threads run through the lumen of the vascular graft and are not fixed regularly along the membrane or stent framework, as is the case with a suture, for example. Thus, the threads preferably run freely from one node to the next through the lumen of the vascular graft.

[0035] The sutures running between the knots are preferably taut and do not form loops. Thus, they provide additional anchorage points for a subsequent vascular implant inserted into this area. However, their taut arrangement does not hinder the insertion of another vascular implant, as they only slightly reduce the opening of the lumen.

[0036] Preferably, adjacent nodes are connected by threads. The threads, together with the nodes between which they run and the corresponding section of the vascular implant, form an arc, in which the thread forms the chord or one side of the resulting polygon, for example, a hexagon or octagon. The connections between the nodes can be limited to one level or, additionally or alternatively, alternate between the levels once or multiple times, for example, in a zigzag pattern.

[0037] The anchoring system according to the invention is particularly suitable in conjunction with the multi-lumen implant known, for example, from WO 2019 / 219728 A1. Here, the anchoring system according to the invention can be provided primarily at the distal ends of the distal branches of the implant.

[0038] Even if the anchoring system according to the invention is described below essentially using the example of a multi-lumen implant, it is suitable for vascular implants in general and for covered vascular implants in particular.

[0039] The known multi-lumen implant comprises a substantially tubular element and a fixing element in the form of a stent or tension ring for fixing the tubular element in a vessel.

[0040] The tubular element is divided into a proximal and a distal section, with the distal section branching into at least two lumens.

[0041] The tubular element is fixed in the target vessel proximal to the aneurysm using one or more fixation elements. The tubular element can be secured to the fixation element(s) by additional means, such as stapling, welding, gluing, suturing, or other known methods. The fixation elements are located in the proximal section of the tubular element.

[0042] The distal section of the tubular element preferably branches into at least two branches, whereby the number of branches is arbitrary and can be determined, for example, by the number of vessels to be supplied. Embodiments with two to five branches are preferred.

[0043] The distal branches of the implant are usually connected to the vessels distal to the implant via covered stents, so-called stent grafts. This bridges the area of ​​the aneurysm, largely preventing blood flow into the aneurysm, and relieving pressure on the aneurysm. At the same time, the distal vessels are specifically supplied with blood via the stent grafts.

[0044] For better fixation of the stent grafts, the anchoring system according to the invention can be provided in the distal regions of the implant, at least in some of the branches. The anchoring system is preferably provided on the membrane of the implant.

[0045] For example, the majority of the threads forming the knots and / or sutures are located on the inside of the branches, i.e., in the lumen of the branches. This also applies to the loops that can be formed by the threads of the sutures.

[0046] The possible arrangements and combinations of the anchoring elements correspond to the basic disclosure of the invention.

[0047] The anchoring system according to the invention can also be provided in addition to already existing elements, such as nitinol rings, stent structures or similar devices, or can comprise these elements.

[0048] The anchoring system according to the invention has the advantage over the prior art that the anchoring elements made of threads are significantly more flexible than known stent-like anchoring elements, while being stable and forming resilient and reliable anchoring points for additional vascular implants. Furthermore, the anchoring system according to the invention, made of anchoring elements formed by threads, can be compressed significantly better than known stent-like anchoring elements. Thus, the anchoring system according to the invention does not lead to an excessive increase in diameter or to a stiffening of the compressed vascular implant, so that there is no noticeable impairment in the maneuverability of the vascular implant in the delivery catheter, and the use of larger-caliber delivery catheters is unnecessary.

[0049] The invention and the technical environment are explained in more detail below with reference to the figures. It should be noted that the figures show a particularly preferred embodiment of the invention. However, the invention is not limited to the embodiment shown. In particular, the invention encompasses, to the extent technically feasible, any combination of the technical features listed in the claims or described in the description as relevant to the invention.

[0050] They show:

[0051] Fig. 1 shows a first embodiment of the

[0052] Anchoring elements in the form of ring or screw-shaped seams;

[0053] Fig. 2 a second embodiment of the

[0054] Anchoring elements in the form of ring- or screw-shaped nodes;

[0055] Fig. 3 a third embodiment of the

[0056] Anchoring elements in the form of a combination of ring or screw-shaped sutures and knots.

[0057] Fig. 4 a combination of the inventive

[0058] Anchoring elements with known reinforcements made of nitinol rings.

[0059] Fig. 5 shows a further combination of anchoring elements according to the invention with known reinforcements made of stent segments.

[0060] Figure 1 shows in Figure A a first embodiment of the anchoring system according to the invention with anchoring elements 4 in the form of ring-shaped or screw-shaped sutures 4a in connection with a multi-lumen implant 1, shown only schematically, with a main lumen 2 and two secondary lumens 3. The anchoring system 4 can also be provided from a single circumferential suture 4a, for example at the proximal end of the secondary lumen 3 as a seam.

[0061] The anchoring system is of course suitable for a wide range of vascular implants, especially for covered vascular implants.

[0062] The sutures 4a thicken the membrane 3a in sections and simultaneously stabilize it, as shown in Figure C. The ring- or screw-shaped sutures 4a form anchor points for the fixation of an optionally inserted additional vascular implant (not shown), so that dislocation or slipping out of the additional vascular implant is significantly less likely than without corresponding anchoring elements 4.

[0063] Preferably, the sutures 4a, as shown in Figure B, are provided such that the section of the suture 4a located on the inner side i of the membrane 3a at least partially has loops 5, which form additional anchor points for an inserted vascular implant. The openings of the loops 5 can be arranged at different angles, for example, perpendicular or parallel to the opening of the vascular implant 1 or the secondary lumen 3.

[0064] Figure 2 shows a second embodiment of the anchoring system according to the invention with anchoring elements 4 in the form of ring- or screw-shaped nodes 4b, again by way of example in connection with a multi-lumen implant 1, shown only schematically, with a main lumen 2 and two secondary lumens 3.

[0065] The nodes 4b form - as shown in Figures B and C - individual thickenings arranged essentially on the inner side i of the membrane 3a, which form anchor points for an inserted vascular implant (not shown).

[0066] The nodes 4b can be arranged in a ring shape, as shown in Figure A1, or in a helical shape, as shown in Figure A2.

[0067] In addition to these two arrangements, various other symmetrical or random arrangement patterns are of course conceivable, which can be adapted to the structure of the vascular implant to be inserted.

[0068] Figure 3 shows a third embodiment of the anchoring system according to the invention with anchoring elements 4 in the form of ring- or helically arranged nodes 4b. The nodes 4b can be arranged in multiple planes; for example, the nodes 4b form a first plane or a first ring, and further nodes 4b form a second plane or a second ring. Preferably, adjacent nodes 4b are each connected by a thread 4c extending into the lumen of the secondary lumens 3.

[0069] The anchoring elements 4 are again shown as an example in connection with a multi-lumen implant 1, which is only shown schematically, with a main lumen 2 and two secondary lumens 3.

[0070] The threads 4c projecting into the lumen are preferably taut between the knots 4a, 4b and thus form the essential anchoring elements 4 alongside the knots 4a, 4b. In this third embodiment, taut tension, as opposed to loose, loop-forming tension as shown, for example, in Figure 1B, has the advantage that an inserted further vascular implant (not shown) cannot become caught in the threads 4c, which might otherwise loop around uncontrollably in the bloodstream.

[0071] This third embodiment preferably comprises the arrangement of at least three nodes 4b, which are connected to one another by three threads 4c, as shown in Figure B2. A plurality of nodes 4b and threads 4c, even in multiple planes, is conceivable, as shown in Figures B1, B3, and C. The nodes 4b are preferably arranged in a ring-shaped, hexagonal, or octagonal configuration.

[0072] Furthermore, embodiments are also conceivable in which not all nodes 4a, 4b are connected to one another by threads 4c, but for example only in pairs, as shown in Figures B4 and B5, wherein embodiment B5 has anchoring elements in several levels, similar to B1.

[0073] Essential to distinguishing this third embodiment from embodiments with sutures, as shown, for example, in Figure 1, is that the anchoring elements 4 according to the third embodiment do not form loose loops and the threads 4c enter the inner lumen i of the multi-lumen implant 1 in such a way that they form abutments for further vascular implants. The threads 4c, together with the nodes 4b between which they run, and the associated section of the secondary lumen 3, accordingly form an arc bo, as shown by way of example in Figure B4. The thread(s) 4c form the chord of the arc, or in other words, the sides of the potentially resulting polygon, for example the hexagon as shown in Figure B3.

[0074] It is clear to the person skilled in the art that this third embodiment does not have to follow the rather symmetrical arrangements of the examples, but here too the nodes 4b and the resulting threads 4c can be arranged asymmetrically and thus lead to asymmetric polygons.

[0075] It is also clear to the person skilled in the art that combinations of the three embodiments mentioned according to Figures 1 to 3 are possible. Figure 4 shows a first possibility of combining the anchoring system according to the invention with anchoring elements 4 with reinforcements made of nitinol rings 6, which are known in vascular implants - such as multi-lumen implants 1. The anchoring elements 4, in the form of nodes 4b, represent anchor points on the inner side i of the membrane 3a and can simultaneously serve as connection points between the membrane 3a and the nitinol ring 6. The nitinol ring 6 can also or alternatively be completely or partially folded into the membrane 3a, with the distal part of the membrane 3a preferably being folded inwards or outwards around the nitinol ring(s) 6 for this purpose. In such a case, the nodes 4b can also serve to fix the folded membrane 3a.

[0076] Corresponding embodiments are possible with a single or a plurality of nitinol rings 6, both in one and multiple planes. Embodiments with a combination of multiple nitinol rings 6 are also conceivable, in which the individual rings 6 have different diameters, whereby the secondary lumens 3 taper distally, for example.

[0077] The nodes 4b increase the roughness of the inner side of the membrane i and prevent or complicate dislocation of the optionally inserted vascular implant (not shown) and in particular its slipping out.

[0078] The nodes 4b also serve as additional fixation points for the nitinol ring 6 or the membrane 3a, thus providing additional security.

[0079] The nodes 4b can be attached symmetrically or asymmetrically.

[0080] It is possible to combine the embodiment according to Figure 4 with further anchoring elements 4 according to Figures 1 to 3.

[0081] Figure 5 shows, similar to Figure 4, a further possibility of connecting the anchoring system according to the invention with reinforcements made of stent segments 7 which are known in vascular implants - such as multi-lumen implants 1.

[0082] The anchoring elements 4 in the form of nodes 4b represent anchor points on the inner side i of the membrane 3a and can simultaneously serve as connection points between the membrane 3a and the stent segment 7. The stent segment 7 can also or alternatively be completely or partially folded into the membrane 3a, whereby for this purpose the distal part of the membrane 3a is preferably folded inwardly or outwardly around the stent segment 7. In such a case, the nodes 4b can also serve to fix the folded membrane 3a.

[0083] Corresponding embodiments are possible with a single-row stent segment 7 as shown in Figure A1 or a multi-row stent segment 7 as shown in Figure A2.

[0084] The nodes 4b increase the roughness of the inner surface of the membrane i and prevent or impede dislocation of the optionally inserted vascular implant and in particular its slipping out.

[0085] The nodes 4b also serve as additional fixation points for the stent segments 7 and the membrane 3a, respectively, and thus provide additional security.

[0086] The nodes 4b can be attached symmetrically or asymmetrically.

[0087] It is possible to combine the embodiment according to Figure 5 with further anchoring elements 4 according to Figures 1 to 3.

[0088] A variety of different vascular implants are known to those skilled in the art. Accordingly, it is clear to the skilled person that the inventive anchoring system is suitable for a variety of vascular implants, and in particular for covered vascular implants. This applies in particular to the areas of a vascular implant into which additional vascular implants are to be inserted and secured. These are usually the distal areas.

[0089] List of reference symbols

[0090] 1 multi-lumen implant

[0091] 2 main lumens

[0092] 3 secondary lumens (3a: membrane)

[0093] 4 Anchoring element (4a: suture, 4b: knot, 4c: thread)

[0094] 5 loops

[0095] 6 Nitinol ring

[0096] 7 Stent segment bo arch i inside a outside p proximal d distal

Claims

Patent claims 1. Anchoring system for vascular implants comprising a plurality of anchoring elements (4) in the form of threads and / or sutures and / or knots formed from threads (4a, 4b) which are provided at least partially on the inside (i) of the vascular implant (1 ).

2. Anchoring system for stent grafts according to claim 1, characterized in that the anchoring elements (4) are arranged in a ring and / or screw shape.

3. Anchoring system for vascular implants according to claim 1 or 2, characterized in that the sutures (4a) have loops (5) which extend into the lumen of the vascular implant (1 ).

4. Anchoring system for vascular implants according to one of the preceding claims, characterized in that the ring-shaped nodes (4b) form a polygon, in particular a hexagon or oxagon.

5. Anchoring system for vascular implants according to one of the preceding claims, characterized in that at least some of the nodes (4a, 4b) are connected to each other by threads (4c).

6. Anchoring system for vascular implants according to claim 5, characterized in that the threads (4c) run through the lumen of the vascular implant (1) such that they, together with the knots (4a, 4b), between which they run, and the associated section of the vascular implant (1) forms an arc (bo) in which the thread (4c) forms the tendon.

7. Vascular implant with an anchoring system (4) according to any one of the preceding claims.

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

9. Vascular implant according to claim 8, wherein the covered vascular implant is a multilumen implant with a main lumen (2) and at least two secondary lumens (3) and wherein the anchoring system (4) is arranged in the distal region of at least one of the secondary lumens (2).

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

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