Vascular implant with asymmetric stent spring

Abstract

The present invention relates to a self-expanding vascular implant (10) implanted in a blood vessel, comprising a hollow cylinder (24) having a proximal end (12) and a distal end (14) and being in a longitudinal direction; comprising stent springs (15, 16, 17, 18, 19, 20) spaced apart from each other and arranged continuously in the longitudinal direction of the hollow cylinder, each stent spring being meandering; and comprising an implant material (22) fixed to the stent springs (15, 16, 17, 18, 19, 20) and connecting them. The support spring (15, 16, 17, 18, 19, 20) has ogives which point alternately in the proximal and distal directions and comprise alternating peaks (26a, 26b, 26c) and valleys (28a, 28b, 28c) connected to each other via legs (30, 31, 32, 33) of different lengths, wherein the support spring (15, 16, 17, 18, 19, 20) has ogives (50, 60) which are arranged circumferentially and continuously and have different heights, and which consist of taller (50a, 60a) and shorter (50b, 60b) ogives.

Description

[0001] This application is a divisional application of Chinese patent application No. 201380070675.7, whose application date is November 21, 2013 and whose invention name is “Vascular implant with asymmetric stent spring”. Technical Field

[0002] The present invention relates to a self-expanding vascular implant for implantation in a blood vessel, comprising a hollow cylinder having a first end and a second end and a longitudinal direction, and further comprising stent springs which are arranged continuously in its longitudinal direction at a certain interval and respectively meander on a circumference, and comprises an implant material fixed to the stent springs and connecting them, the stent springs are connected only via the implant material and are not connected to each other, and the stent springs on the circumference have pointed arches alternately facing the proximal direction and the distal direction and have alternating apexes and lowest points connected to each other by legs. Background Art

[0003] Such vascular implants are known in the prior art, for example from DE 103 37739.5.

[0004] In order to treat an aneurysm in an artery, it is generally known to implant an intraluminal vascular implant, which is also called an intravascular stent / stent graft. An aneurysm is understood to be a widening or bulging (protrusion) of an arterial vessel as a result of congenital or acquired changes in the wall. The protrusion may have an effect on the wall as a whole or, in the case of a so-called pseudoaneurysm or a so-called dissection, blood may flow from the lumen of the artery between the layers of the wall and may tear them apart. Not treating an aneurysm may lead to a rupture of the artery in a late stage, with the result that the patient has internal bleeding.

[0005] The self-expanding vascular implant for treating such aneurysms is usually composed of a hollow cylindrical metal frame, whose side surface is covered with a fabric or polymer film, thereby obtaining a hollow cylinder. In order to implant, the vascular implant is axially compressed so that its cross section is significantly reduced. Subsequently, with the help of an insertion system, the vascular implant is brought into the region of the aneurysm, where it is released. Due to the rebound of the metal frame, the vascular implant is expanded into its original shape again, thereby unfolding its outer jacket surface, which becomes clamped from the inside in the proximal and distal blood vessels relative to the aneurysm. In this way, blood can now flow through the vascular implant, and further avoids the load of protrusion.

[0006] The metal frame of such a vascular implant usually consists, for example, of a wire mesh or of so-called stent springs arranged one after the other in a row, which are possibly connected to one another via a support of connecting wires or simply connected to one another via the implant material. The wire mesh or stent spring is usually a shape memory metal, usually nitinol, which, after being introduced into the tube, changes back into an expanded state for release and thus "unfolds" the vascular implant.

[0007] In the case of vascular implants known from the prior art, in particular those with circumferentially meandering stent springs (which are either connected to one another only by the implant material and thus only indirectly, or are additionally connected to one another by connecting legs or supports), there is a risk of kinking / buckling during introduction into the vessel, and in particular whenever the vascular implant is introduced or guided through a bend in the vessel. This kinking occurs in particular whenever an attempt is made to adapt the vascular implant to the natural shape of a curved vessel and to advance said bend in the region of two or more stent springs arranged one behind the other: in this region, the lowest point of one stent spring and the apex of the stent spring arranged distally thereafter are usually located opposite one another, so that the vascular implant is susceptible to buckling here due to the small intermediate space located between these two points and formed only by the implant material.

[0008] Such kinks / folds are extremely disadvantageous since, when a kink is present, a regular blood flow through the vessel is no longer ensured and, as a result, stenosis and turbulence of the blood within the vascular implant may occur, or even vessel occlusion may occur. Summary of the invention

[0009] It is therefore an object of the present invention to provide a vascular implant with which the risk of kinking of the vascular implant can be avoided or at least minimized while maintaining the longitudinal stability of the vascular implant.

[0010] According to the invention, this object is achieved by developing the vascular implant described at the beginning, wherein at least two support springs are arranged successively one after another in the longitudinal direction, respectively having legs of different lengths, for forming circumferentially successive pointed arches of different heights, with higher and shorter pointed arches, and the higher pointed arch of the first support spring in the proximal direction is positioned opposite the shorter pointed arch of the second support spring arranged behind it on the proximal side in the distal direction at a certain distance and at a virtual line running parallel to the longitudinal direction of the vascular implant.

[0011] Due to the design of different leg lengths and the different heights of the pointed arches that are alternately oriented in the proximal direction and the distal direction, the overall shape of the support spring is asymmetric. The support spring, i.e. at least two, preferably all support springs of the vascular implant, therefore has an irregular "amplitude", i.e., the pointed arches that vary in height due to different leg lengths. Therefore, according to the present invention, higher and shorter pointed arches are alternately formed in the circumferential direction of the support spring. Here, the terms "different heights" and "higher" and "shorter" are intended to relate to the relationship between the pointed arches. The highest pointed arch of the support spring therefore has the longest leg relative to the other legs of the same support spring. The length of the longest leg of the support spring therefore also predetermines the height of the support spring, that is to say the support spring height. It goes without saying that - although the lengths of the legs that directly follow each other are different - a support can have multiple legs of the same length, but according to definition, the connection between the legs of the same length is interrupted by the legs of other lengths.

[0012] The combination of these asymmetric stent springs with at least two stent springs arranged one after the other in the following manner advantageously achieves the following effect: the bending of the vascular implant according to the invention in the vessel does not lead to wrinkles, or this wrinkle is avoided to the greatest extent, or only occurs in the case of significantly smaller radii, and the risk of kinking is greatly reduced, the manner being such that the higher pointed arch of the first stent spring in the proximal direction is in place against the shorter pointed arch of the second stent spring arranged behind it in the distal direction. Due to the fact that the higher pointed arch of the first stent spring in the proximal direction is opposite to the shorter pointed arch of the second stent spring arranged behind it in the distal direction at a certain spacing and at a virtual line parallel to the longitudinal direction of the vascular implant, the longitudinal / axial rigidity is good, accompanied by high flexibility. Under bending, the long and short vertices quasi engage with each other. As a result, the stent graft is also very flexible in three dimensions.

[0013] The cusps that alternately face the proximal direction and face the distal direction are also referred to (in other terms) as "peaks" and "troughs", with the "peaks" referring to the cusps facing the proximal direction and the "troughs" referring to the cusps facing the distal direction. In the described embodiment, an asymmetrical meandering shape of the support spring on the circumference is obtained, with two consecutive peaks (or cusps facing the proximal direction) of different heights, and therefore also a trough (or cusps facing the distal direction) located between them of different depths. Thus, in an alternating manner, in the circumferential direction, a higher crest / apex is followed by a crest / apex that is lower or less high than the previous crest / apex, and this crest / apex is again followed by a crest / apex that is higher than the crest / apex that is directly before it, and so on, so that troughs / minimums of different depths are located between the crests / apex of different heights: and with respect to the troughs / minimums, a lower trough / minimum is again followed in an alternating manner in the direction of circumferential progression by a trough / minimum that is less low than the trough / minimum that is directly before it in the direction of circumferential progression, and this trough / minimum is again followed by a trough / minimum that is lower than the one that is before it. In other words, the support spring thus has an arch having at least two or three minima of different depths, the different depths being related to an imaginary line that runs around perpendicularly to the longitudinal direction of the hollow cylindrical body and connects the lowest minima to one another. Therefore, by definition, the less low minima are not located on this imaginary line, and the same applies to the apex.

[0014] Similarly, in other aspects, according to the vascular implant according to the present invention, at least two support springs arranged consecutively in the longitudinal direction are arranged relative to the longitudinal direction of the hollow cylindrical body and relative to each other, so that the lowest point of the pointed arch of the first support spring is positioned at a certain distance and at a virtual line advancing parallel to the longitudinal direction of the vascular implant, respectively opposite to the apex of the pointed arch of the second support spring arranged behind the first support spring in the longitudinal direction of the vascular implant, and more precisely, so that the lowest point of the pointed arch of the first support spring is positioned at a certain distance opposite to the apex of the second support spring arranged behind it on the distal side, and this apex is not as high as the highest apex of the second support spring; accordingly, in this embodiment, the lowest point that is not as low (that is, the lowest point that is not as low as the lowest lowest point of the first support spring) is also always positioned at a certain distance from the highest apex of the second support spring arranged behind it on the distal side and opposite to the highest apex of the second support spring arranged behind it on the distal side, and the highest apex is higher than the less high apex of the second support spring.

[0015] It goes without saying that the support spring as a whole can have legs of its ogive of different lengths, or in addition it can actually have only three or more different lengths. The relative spacing between a vertex and a lowest point of the support spring or the relative spacing between all vertex and lowest points can also be changed.

[0016] The vascular implant according to the invention achieves the following effect: there are two different bending planes between adjacent oppositely positioned cusps, whereby the vascular implant becomes significantly more flexible, but retains its longitudinal stability. At the same time, it can be bent in multiple planes without wrinkles.

[0017] In combination with the different leg lengths, this phase arrangement of at least two, preferably all, stent springs of the vascular implant provides the vascular implant with an asymmetric pattern, so that bending of the vascular implant according to the invention in the vessel does not lead to wrinkles, or such wrinkles are avoided to a maximum extent or only occur in the case of significantly smaller radii and the risk of wrinkles is greatly reduced.

[0018] In this way, the objects on which the invention is based are fully achieved. DETAILED DESCRIPTION

[0019] As discussed at the beginning, in the present context, a "support spring" is understood to be any annular element which (due to its material) can be compressed and which can expand again in the manner of a spring after the compression pressure is removed. "Meandering" is understood in this context to mean any wavy, coiled or ring-like shape of a support spring or support wire, each support spring being formed integrally in the form of one component, that is, formed by a support spring ring that meanders circumferentially. Accordingly, a "meandering support spring" in this context is an annular support element that expands in the manner of a spring and can be compressed and has a wavy, ring-like or coiled shape with alternating peaks and troughs.

[0020] In the vascular implant according to the invention, the ogee is respectively formed by two legs and an apex (in the case of an ogee pointing in the proximal direction) or a nadir (in the case of an ogee pointing in the distal direction) located between the legs.

[0021] Due to the different lengths of the legs, cusps of different heights are obtained, whose heights are determined relative to a virtual line that advances in the circumferential direction of the support spring and is perpendicular to the longitudinal direction of the vascular implant, passing through the highest apex / apex of the cusp in the proximal direction. Due to this design and definition, there are always vertices below this virtual line passing through the highest apex and therefore representing vertices that are shorter than the highest apex. The same is true with regard to the cusp or lowest point in the distal direction: here too, a virtual line is drawn in the circumferential direction of the support spring through the apex / apex of the cusp in the distal direction, so that there are higher and shorter apex of the cusp in the distal direction.

[0022] Heights that can be given as examples for different ogives are, for example, in the range of 4 to 18 mm, preferably about 8 to 14 mm, for the tallest ogives, that is, for ogives that are taller than the shorter ogives, and 4 to 10 mm, preferably 6 to 8 mm, for the shorter ogives. A person skilled in the art will recognize that the support spring can on the one hand comprise a plurality of ogives with at least two or three or more than four ogives of different heights. If there are three ogives of different heights, the support spring therefore has three different heights in terms of the ogives, that is, at least one first, higher ogive of the tallest height, at least one second ogive of a height shorter than the height of the first ogive, and a third ogive of a height in turn shorter than the height of the second ogive, and so on. The heights that may be given as examples, which in this case are used for illustrative purposes only and are not intended to be limiting, are, for example: 10 mm (higher pointed arch) and 8 mm (shorter pointed arch); 12 mm (higher pointed arch) and 8 mm (shorter pointed arch); 12 mm (higher pointed arch) and 9 mm (shorter pointed arch); 12 mm (higher pointed arch) and 10 mm (shorter pointed arch); 16 mm (higher pointed arch) and 14 mm (shorter pointed arch), 16 mm (higher pointed arch) and 13 mm (shorter pointed arch); 16 mm (higher pointed arch), 12 mm (shorter pointed arch) and 10 mm (still shorter pointed arch); 10 mm (higher pointed arch) and 8 mm (shorter pointed arch); 12 mm (higher pointed arch), 10 mm (shorter pointed arch) and 8 mm (still shorter pointed arch).

[0023] In the present case, and throughout the specification, the term "about" is intended to indicate that the representations given for ranges and numbers are also intended to include those ranges and numbers that are included by those skilled in the art because of measurement differences or tolerances and that are suitable for achieving or contributing to the purpose on which the invention is based.

[0024] As used herein, with respect to a vascular implant, the term "proximal" generally refers to the portion or end of a vascular implant that is located proximal to the heart of a patient to be treated.

[0025] Accordingly, in this context, "distal" indicates a portion or end of a position, direction or component of the vascular implant according to the invention which is / leads to the position, direction or component which is / leads to the position, direction or component which is / are further / farthest from the heart of the patient.

[0026] Accordingly, in this context, the “proximal” end / opening and the “distal” end / opening of a vascular implant are the ends / openings through which the flow of blood through the hollow cylindrical body of the vascular implant is ensured: when the vascular implant according to the invention is implanted in a blood vessel, such as for example the aorta, blood from the heart thus flows through the proximal end / opening of the vascular implant and leaves the vascular implant through its distal opening.

[0027] By definition, the stent springs are not directly connected to one another and do not have any legs or struts or similar connecting elements between one another. The stent springs are only connected to one another by / via the implant material to which the stent springs are fixed, thereby forming an "indirect connection" between the stent springs. Thus, stent springs arranged successively in the longitudinal direction of the vascular implant are arranged at a certain distance from one another and do not touch one another in the unbent state of the vascular implant. The spacing between the stent springs can vary and depends in particular on the intended use and properties of the vascular implant; the spacing given as an example is between 1 mm (even 0 mm in the case of long points twisted relative to one another) and 20 mm, advantageously 1 to 4 mm.

[0028] Furthermore, in the context of this document, "stent" refers to any device or structure that provides expansion forces and / or support functions due to the resilient metal framework of the implant.

[0029] In this context, and also in the prior art, the expression "stent-graft" is intended to mean an implant having a stent and also attached thereto an implant ("graft") material which forms a lumen through at least a portion of the implant.

[0030] The vascular implant according to the invention furthermore has the effect of allowing a rotation of the implant, even in a bent state, so that here too a three-dimensional bending can be achieved without the product or the implant buckling in the vessel.

[0031] In the case of vascular implants known from the prior art with stent springs arranged one behind the other, rotation in the bent state is not possible, because here, as a result of the symmetrical stent springs, buckling occurs. The buckling in the case of stent springs known from the prior art is therefore due to the symmetrical meandering form of the stent springs and the symmetrical arrangement of the stent springs in the longitudinal direction. This symmetrical arrangement of the stent springs in the longitudinal direction leads to the above-mentioned buckling when the vascular implant from the prior art undergoes bending.

[0032] Furthermore, with the alternating position of the pointed arches of the vascular implant or stent spring according to the invention and after loading the vascular implant into an insertion system (in which the arches of the stent spring in particular take up a lot of space), the vascular implant can advantageously be compressed to a significantly higher degree and can thereby be loaded into a small insertion catheter.

[0033] According to a further embodiment of the vascular implant according to the present invention, it is preferred that if at least three legs directly following one another in the circumferential direction of the support spring have different lengths, the first leg connects the first lowest point to the first vertex, the second leg connects the first vertex to the second lowest point following in the circumferential direction, and the third leg connects the second lowest point to the second vertex following in the circumferential direction.

[0034] According to an embodiment of the vascular implant according to the invention, it is preferred if the proximally directed cusps are each formed by two legs of equal length and if, in the circumferential direction of the support spring, the higher cusps in the proximally directed direction alternate with the shorter cusps in the proximally directed direction. Thus, in the case of this embodiment, the higher cusps in the proximally directed direction always alternate with the shorter cusps in the proximally directed direction which are shorter than the higher cusps; the shorter cusps in turn are followed by the higher cusps in the distal direction, which may be as high as the higher cusps preceding the shorter cusps, etc. Due to the design of the support spring, i.e. because the cusps in the proximally directed direction always share a leg with the cusps in the distal direction which directly follows them, the cusps in the distal direction of this embodiment are each formed by two legs of different lengths. Thus, the cusps in the distal direction all have the same height, so that the support spring is particularly suitable for attachment as a terminal support spring at the distal end of the vascular implant.

[0035] In another embodiment, it is preferred if, in the circumferential direction of the support spring, higher pointed arches in the proximal direction x alternate with shorter pointed arches in the proximal direction x, and higher pointed arches in the distal direction y alternate with shorter pointed arches in the distal direction y.

[0036] In yet another embodiment, it is preferred if at least one support spring has in its circumferential direction ogives in the proximal and / or distal direction x or y which are formed as follows: a high ogive is followed by a shorter ogive, and a shorter ogive is followed by an ogive that is shorter than the previously arranged shorter ogive, and this shorter ogive is in turn followed by a higher ogive, etc. In this embodiment, therefore, the “triple pattern” consisting of high ogives, shorter ogives and still shorter ogives is actually in accordance with such a triple pattern, by which, by definition, an asymmetrical support spring is again provided.

[0037] According to yet another embodiment, it may be preferred if in at least one stent spring, in its circumferential direction, the ogives in the proximal direction are all of the same height and alternate with ogives in the distal direction of different height.

[0038] In the case of the various embodiments presented above, an asymmetrical support spring and an asymmetrical support-spring arrangement according to the invention can be obtained.

[0039] According to another embodiment, it is preferred if the distance z1 between a first apex in the circumferential direction and a first lowest point after the first apex of at least one support spring is different from the distance z2 between the first lowest point in the circumferential direction and a second apex after the first lowest point of the same support spring.

[0040] This embodiment has the advantage that additional asymmetries can be created, whereby buckling of the vascular implant can be further reduced.

[0041] According to an embodiment of the vascular implant according to the invention, it is preferred if the self-expanding vascular implant according to the invention has at least three stent springs arranged in series in the longitudinal direction which are not directly connected to one another but are connected to one another only via implant material.

[0042] According to a further embodiment, it is preferred if the vascular implant according to the invention has between three and ten, preferably three, four, five, six, seven, eight, nine or ten, stent springs arranged one behind the other.

[0043] The number of stent springs will depend on the desired length of the vascular implant to be used, or on the patient's vascular defect to be bridged.

[0044] Furthermore, the number of apexes and nadirs, or the number of cusps alternating in the proximal and distal directions, of the vascular implant according to the invention will depend on the diameter of the vessel or the portion of the vessel to be treated. Thus, for example, in the case of a vascular implant for use in the arterial system of an adult patient, it is preferred if it has between six and twelve cusps in the proximal direction and between six and twelve cusps in the distal direction.

[0045] It is self-evident that the treating surgeon, based on the diameter of the tube and the extent of the vascular region to be treated, can pre-set the size, based on which the optimal number of stent springs can be determined, and the number of apexes or apices and nadirs can also be determined.

[0046] In the case of the vascular implant according to the invention, the support springs are fixed to the implant material at a specific spacing from each other. The support springs are preferably attached by sewing or adhesive. The spacing between the support springs arranged consecutively in the longitudinal direction is such that the vascular implant has sufficient overall stability and good bending ability. Therefore, the spacing between two support springs arranged consecutively in the longitudinal direction, measured between the lowest lowest point of the first support spring and the highest vertex of the second support spring arranged thereafter on the distal side, is between about 0 mm and about 5 mm - the lowest lowest point and the highest vertex do not necessarily have to be in position opposite each other.

[0047] According to a preferred embodiment of the self-expanding vascular implant according to the invention, the stent spring consists of a self-expanding material, preferably Nitinol.

[0048] Nitinol is currently the material most frequently used for self-expanding vascular implants with stent springs. Nitinol has the following advantages: it has a "shape memory" property, which means that the stent springs of Nitinol are made in an expanded state, can be compressed for insertion into a tube, and after the compression means (usually the sheath is withdrawn) are removed, the stent springs return to their own expanded initial state again due to the "shape memory" property. As a result, the vascular implant as a whole settles against the vessel wall, and it is pressed against the vessel wall due to the spring behavior of the stent spring, so that it is firmly anchored in the vessel.

[0049] As already mentioned above, it is preferred if the stent springs are sewn to the implant material one behind the other in the longitudinal direction of the vascular implant at a certain distance from one another.

[0050] This approach has the advantage that the support springs can be fixed to the implant material differently and even at different spacings from each other, so that, for example, two support springs arranged one after the other have a greater spacing from each other than two other support springs located further distally or more proximally. In this way, the vascular implant can be adapted to the tube portion to be treated, where the vascular implant can also have, for example, fenestrations in its longitudinal direction and / or on its circumference, which represent openings for the output tube in the area to be treated. Providing fenestrations in the implant material (usually side branches extending from the vascular implant to the connection) ensures the blood supply of the tube branching out in this area, even after the vascular implant has been introduced into the tube.

[0051] It goes without saying that the fenestration in the implant material is arranged between two support springs arranged one behind the other. In this case, the fenestration can be adapted to the spacing between the two support springs, or else the spacing of the two support springs from each other can be adapted to the size of the fenestration. Furthermore, several fenestrations can be arranged circumferentially on the implant material between two support springs arranged one behind the other, and the fenestrations can be distributed in the longitudinal direction of the vascular implant.

[0052] A person skilled in the art will recognize at which points of the vascular implant according to the invention fenestrations must be provided and will be able to arrange them according to the specific properties of the individual tubes.

[0053] In the case of the vascular implant according to the invention, it is preferred if the implant material comprises a material selected from polyester, polyurethane, polystyrene, polytetrafluoroethylene or ultra-high molecular weight polyethylene (UHMPE) or mixtures thereof.

[0054] The use of these materials in medicine is known per se, in particular also for vascular implants, so that a person skilled in the art can select a suitable material for the specific use of a vascular implant based on his knowledge.

[0055] The present invention therefore also relates to another embodiment of the vascular implant according to the invention, which is formed in the following way: in addition to at least one hollow cylinder, there is at least one branching side body branching off from the hollow cylinder of the vascular implant. The side body is also a hollow cylinder, which contains the stent springs arranged in succession and the implant material connecting them, and the side body is intended for the tube branching off from the main tube. The side body usually has a smaller diameter than the "main body" of the vascular implant.

[0056] At least one side body can be made of a scaffolded part (i.e. a part with a scaffold spring or a scaffold wire mesh), or can have such a scaffolded part, or otherwise can have an unscaffolded part made of only implant material, or be made of such an unscaffolded part. The materials constituting the side body are usually also those materials from which the main body is made.

[0057] In a special embodiment of the vascular implant according to the invention, it may also be preferred if the vascular implant has different diameters in its longitudinal direction.

[0058] This embodiment has the advantage that it can be used in narrowed or tapered tubes, or otherwise in branched tubes, such as for example at the bifurcation of the aorta.

[0059] Further advantages and features will become apparent from the following description and the accompanying drawings.

[0060] It goes without saying that the features mentioned above and still to be explained below can be used not only in the respectively specified combination but also in other combinations or alone without departing from the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Exemplary embodiments of the invention are shown in the accompanying drawings and are described in more detail below with reference to them. In the drawings:

[0062] FIG. 1 shows an exemplary embodiment of a prior art vascular implant in an unbent form.

[0063] Fig. 2a shows an embodiment of a vascular implant according to the invention in an unbent state.

[0064] FIG. 2 b shows an enlarged portion of the vascular implant according to the present invention from FIG. 2 a ;

[0065] FIG3 a shows a diagram of an exemplary embodiment of a prior art vascular implant in a bent state;

[0066] FIG. 3 b shows the exemplary embodiment of the vascular implant according to the invention from FIG. 2 a , also in a bent state.

[0067] 4 shows schematic diagrams of an exemplary design and arrangement of two stent springs arranged one after another according to a vascular implant of the present invention, A: two different heights for the pointed arch facing the proximal direction or the distal direction; and B: three different heights for the pointed arch facing the proximal direction or the distal direction; and

[0068] Figure 5 A schematic diagram showing an exemplary routing of a stent spring for use with a vascular implant according to the invention is shown.

[0069] 1 shows a self-expanding vascular implant as known in the prior art. This vascular implant 100 has support springs 101, 102, 103, 104, 105, 106 arranged one behind the other in the longitudinal direction, each having a vertex 108 and a lowest point 109, or a pointed arch 120 in the proximal direction x and a pointed arch 130 in the distal direction y.

[0070] As shown in Fig. 1, the apex 108 of the support springs 101, 102, 103, 104, 105, 106 is connected to the lowest point 109 of the same support spring 101, 102, 103, 104, 105, 106 respectively by a leg 110, and the lowest point is then connected to the following apex 108 by a leg 110. Fig. 1 also shows that the alternating route between the apex and the lowest point results in a symmetrical serpentine shape of the support springs 101, 102, 103, 104, 105, 106. The support springs 101 to 106 are attached to the implant material 112 and more precisely in such a way that the support springs 101 to 106 are arranged symmetrically: on the one hand, the legs of all the support springs 101, 102, 103, 104, 105, 106, which respectively connect the apex 108, the lowest point 109, the apex 108, the lowest point 109, etc. of the support springs 101, 102, 103, 104, 105, 106 to each other, are of the same length, so that the apex 108 and the lowest point 109 on the circumference are at the same height - or, in other words, at the same amplitude. On the other hand, the support springs of the vascular implant of the prior art, which are arranged one after another in the longitudinal direction, are arranged at a certain distance from each other in such a way that the lowest point 109 of the support spring 101 is located opposite the apex 108 of the support spring 102 located distally, and they do not directly touch or directly connect to each other. Accordingly, the lowest point 109 of the second support spring 102 is then also directly assigned to the apex 108 of the distal support spring 103, so that the two points of the two support springs 102, 103 are located opposite each other, and here there is also a certain distance between the two support springs 102, 103. Due to this arrangement, an overall symmetrical pattern or symmetrical arrangement of the support springs 101, 102, 103, 104, 105, 106 arranged in the longitudinal direction of the vascular implant 100 is obtained.

[0071] Embodiments of a vascular implant according to the invention are described below. One embodiment is drawn schematically and not to scale in Figures 2a and 2b.

[0072] The embodiment of the vascular implant 10 according to the invention shown in FIG. 2 a has a proximal end 12 and a distal end 14 and has support springs 15 , 16 , 17 , 18 , 19 , 20 arranged one after the other in the longitudinal direction, which are not directly connected to one another but are connected only via implant material 22 , thus forming a hollow cylinder 24 .

[0073] The support springs 15 to 20 are each formed integrally in the form of one component and are formed in a wave-like or ring-like manner on the circumference, and thus extend in a meandering manner on the circumference of the vascular implant 10. In FIG. 2 , the proximal direction is also indicated by x and the distal direction is also indicated by y, and the respective directions are also indicated by arrows. According to the present invention, the support springs 15, 16, 17, 18, 19, 20 of the vascular implant 10 have a pointed arch 50 facing the proximal direction x and a pointed arch 60 facing the distal direction y, and not all of the pointed arches are provided with reference numerals, but only two pointed arches 50 and 60 of the support springs 18 and 19 are provided as examples for the purpose of clarity. In other words, the pointed arches 50, 60 of the support springs form a wave on the circumference, with a wave crest corresponding to the pointed arch 50 and a wave trough corresponding to the pointed arch 60.

[0074] The individual support springs 15 to 20 each have a vertex 26a, 26b, 26c and a nadir 28a, 28b, 28c, wherein the term "vertex" is used here to designate the highest point / peak of a wave when viewed in the proximal direction, and the term "nadir" is used here to designate the lowest point / trough of a wave. Here, too, for the sake of clarity, not all vertexes and nadirs of all support springs are provided with reference numerals. The vertex 26a, 26b, 26c thus respectively designates the highest point of the cusp 50 in the proximal direction x, and the nadir 28a, 28b, 28c respectively designates the highest point of the cusp 60 in the distal direction y.

[0075] As shown in FIG. 2 , the support springs 16 , 17 , 18 , 19 are sewn to the implant material 22 by means of sutures 40 .

[0076] Typically (and as already mentioned further above), when referring to a self-expanding vascular implant or a stent graft or an intraluminal implant, the terms "distal" and "proximal" are (typically and in this context) used to refer to the respective ends of the vascular implant, the term "distal" referring to the portion or end that is located further downstream relative to the blood flow. On the other hand, the term "proximal" refers to the portion or end that is located further upstream of the blood flow, also relative to the blood flow. In other words, the term "distal" means in the direction of the blood flow, and the term "proximal" means opposite to the direction of the blood flow. In contrast, when referring to a catheter or an insertion system for a self-expanding vascular implant, the term "distal" refers to the end of the catheter or insertion system that is inserted into the patient or is seen as further away from the user of the catheter / insertion system; and the term "proximal" refers to the end of the catheter / insertion system that is closer to the user.

[0077] FIG. 2 a and FIG. 2 b , which is partially enlarged, show that at least one of the support springs 15 to 20 has legs 30, 31, 32, 33, which respectively connect the first lowest point 28a with the first vertex 26a, the vertex with the second lowest point 28b, the lowest point 28b with the second vertex 26b, and the vertex 26b with the third lowest point 28c, and the lowest point 28c subsequently with the vertex 26c. The legs 30, 31, 32 have different lengths, thereby forming ogives 50, 60 with different heights (see also FIG. 4 ). As a result, an overall asymmetrical shape of the ogives or “waves” of the support springs 15, 16, 17, 18, 19, 20 is obtained, thereby achieving reduced buckling.

[0078] 2a and 2b also show that the support springs 17 and 18 are arranged relative to each other in the following manner: the taller cusps 50a of the first support spring 18 in the proximal direction x are positioned opposite the shorter cusps 60b of the second support spring 17 arranged behind it in the proximal direction x in the distal direction y at a certain distance and at an imaginary line (A) parallel to the longitudinal direction of the vascular implant 10. Similarly, the shorter cusps 50b of the first support spring 18 in the proximal direction x are positioned opposite the taller cusps 60a of the second support spring 17 arranged behind it in the proximal direction x in the distal direction y at a certain distance and at an imaginary line (A) parallel to the longitudinal direction of the vascular implant 10.

[0079] Combined with the asymmetric meandering shape of the individual stent springs 15, 16, 17, 18, 19, 20, this arrangement also provides the vascular implant with an asymmetric arrangement of the individual stent springs 15, 16, 17, 18, 19, 20 relative to each other, and this further asymmetric design also enhances the effect of avoiding wrinkles.

[0080] The effect of avoiding buckling is shown diagrammatically in Figure 3: In this case, Figure 3a shows a vascular implant 100 known from the prior art and placed in a bent state. The vascular implant 100 known from the prior art buckles severely at the bends, which can significantly impair the blood flow through the vessel.

[0081] In contrast, as shown in FIG. 3 b , an embodiment of the vascular implant 10 according to the invention does not show any wrinkles in the bent state; here, at most small creases are formed in the implant material 22 , rather than wrinkles between two support springs 15 , 16 , 17 , 18 , 19 , 20 arranged one after another as in the case of the vascular implant 100 known in the prior art.

[0082] FIG. 4 additionally shows two (or three) downstream support springs 17 and 18 ( Figure 4A ) and 17, 18 and 19 ( Figure 4B ) are shown in two exemplary schematic designs and arrangements. Here, in order to indicate the same features as in Figures 1 to 3, the same reference numerals are used.

[0083] Figure 4A The asymmetrical meandering shape of two support springs 17 and 18 of an exemplary embodiment of a vascular implant according to the present invention is shown: the support springs 17 and 18 have alternating cusps 50 in the proximal direction x and cusps 60 in the distal direction y. The cusps 50 in the proximal direction x alternately include high or taller cusps 50a and shorter cusps 50b, which are shorter than the cusps 50a in the proximal direction x arranged before them respectively. In addition, the support springs 17 and 18 each include cusps 60 in the distal direction y, with taller cusps 60a and shorter cusps 60b. In this case, the two support springs 17, 18 are arranged with respect to their cusps: the taller cusps 60a in the distal direction x of the support spring 17 are positioned opposite the shorter cusps 50b of the support spring 18 arranged behind it in the distal direction y at a certain spacing and at an imaginary line A parallel to the longitudinal axis of the vascular implant or perpendicular to the circumference of the support springs 17, 18.

[0084] Figure 4BAnother embodiment is shown: here, three cusps of different heights in the proximal direction x are alternated in the following manner: a taller cusp 50a adjoins a shorter cusp 50b, and the latter adjoins a cusp 50c which is even shorter than cusp 50b; the shorter cusp 50c then adjoins a taller cusp 50a, which in turn is followed by a shorter cusp 50b, etc. Due to this design, cusps 60 in the distal direction y are arranged in the circumferential direction of the support spring 17 such that a shorter cusp 60c is followed by a cusp 60b which is taller than cusp 60c, and this cusp 60b is followed by a taller cusp 60a which is taller than cusp 60b. Thus, cusps 50b and 60b each have a height between the heights of the taller and shorter cusps 50a and 50c, and the heights of 60a and 60c, respectively.

[0085] With the vascular implant according to the present invention, the two stent springs 17 and 18 are arranged one after another so that the taller pointed arch 50a of the stent spring 18 in the proximal direction is positioned against the shorter pointed arch 60c of the stent spring 17 in the distal direction, the pointed arch 50b of the stent spring 18 is positioned against the pointed arch 60b, and the shorter pointed arch 50c of the stent spring 18 in the proximal direction is positioned against the taller pointed arch 60a of the stent spring 17 in the distal direction. Figure 4B The support springs 17 , 18 and 19 shown in FIG. 1 and arranged one behind the other allow the overall asymmetrical arrangement to be easily recognized.

[0086] Figure 5 Finally, various designs of support springs suitable for the purposes of the present application are shown, with asymmetrically formed ogives of different heights. With an asymmetrical arrangement according to the invention of such support springs relative to one another and in a continuous sequence, and in combination with individual asymmetrical support springs, vascular implants can be formed, by which buckling in the tube can be advantageously avoided as described herein.

[0087] exist Figure 5 The exemplary stent spring shapes shown in the four embodiments in FIG. 1 show different variants and possibilities for forming an asymmetric stent spring, wherein in the three embodiments above, two different heights of the pointed arches in the proximal direction x and in the distal direction y are described, while in Figure 5 The bottom bracket spring has three pointed arches of different heights.

[0088] Moreover, in Figure 5 The two upper support springs shown in FIG. 1 show two different heights of the pointed arches, respectively in the distal direction and in the proximal direction, which can also have different values: thus, in Figure 5 In the uppermost example shown in , the difference between the heights of the pointed arches is greater than in the second uppermost example.

[0089] Furthermore, the number of ogives of the support spring can be adjusted by the spacing between the ogives in the proximal direction x and the distal direction y respectively: the smaller the spacing, the more ogives the support spring can have, which can be seen in particular from the third example.

[0090] Finally, in the lowermost example, the shape of the pointed arch in the proximal and distal directions is shown, each with three different heights.

[0091] exist Figure 5 The uppermost example in FIG. 1 also shows that the spacing z1 between the first vertex 26a and the first lowest point 28a following the first vertex 26a in the circumferential direction of at least one support spring is different from the spacing z2 from the second vertex 26b following the first lowest point 28a to the first lowest point 28a in the circumferential direction of the same support spring. As a result, further asymmetry is achieved.

Claims

1. A self-expanding vascular implant (10) for implantation in a blood vessel, the self-expanding vascular implant (10) comprising a hollow cylinder (24) having a proximal end (12) and a distal end (14) and a longitudinal direction, and further comprising stent springs (15, 16, 17, 18, 19, 20) arranged continuously at a certain interval in the longitudinal direction thereof and respectively winding on the circumference, and comprising an implant material (22) fixed to the stent springs (15, 16, 17, 18, 19, 20) and connecting them, wherein The spacing between two support springs arranged consecutively in the longitudinal direction is measured between the lowest lowest point of the first support spring and the highest apex of the second support spring arranged behind it on the distal side, the support springs (15, 16, 17, 18, 19, 20) are connected only by the implant material (22) and are not connected to each other, and the support springs (15, 16, 17, 18, 19, 20) on the circumference have pointed arches that alternately face the proximal direction x and the distal direction y, and the pointed arches are connected to each other by legs, characterized in that At least three support springs (15, 16, 17, 18, 19, 20) arranged in succession in the longitudinal direction respectively have legs (30, 31, 32, 33) of different lengths to form circumferentially arranged pointed arches (50, 60) of different heights, with higher (50a) and shorter (50b) pointed arches, the higher (50a) and shorter (50b) pointed arches extending in both the proximal and distal directions of the respective support springs (15, 16, 17, 18, 19, 20), Each of the at least three support springs (15, 16, 17, 18, 19, 20) has at least three legs (30, 31, 32, 33) of different lengths arranged continuously in the circumferential direction, and wherein the taller pointed arch (50a) of the first support spring (18) in the proximal direction x is positioned opposite to the shorter pointed arch (60b) of the second support spring (17) arranged thereafter in the proximal direction x in the distal direction y at a certain distance and at a virtual line (A) parallel to the longitudinal direction of the vascular implant (10), and / or wherein the shorter pointed arch (50b) of the first support spring (18) in the proximal direction x is positioned opposite to the longer pointed arch (60a) of the second support spring (17) arranged thereafter in the proximal direction x in the distal direction y at a certain distance and at a virtual line (A) parallel to the longitudinal direction of the vascular implant (10), The legs that directly follow each other are of different lengths.

2. The self-expanding vascular implant according to claim 1, characterized in that In the circumferential direction of the support spring (15, 16, 17, 18, 19, 20), the higher pointed arches (50a) in the proximal direction x alternate with the shorter pointed arches (50b) in the proximal direction x, and the higher pointed arches (60a) in the distal direction y alternate with the shorter pointed arches (60b) in the distal direction y.

3. The self-expanding vascular implant (10) according to claim 1, characterized in that In at least one support spring (15, 16, 17, 18, 19, 20), in the circumferential direction, a pointed arch (50) is formed toward the proximal direction x so that a high pointed arch (50a) is followed by a shorter pointed arch (50b), and the shorter pointed arch (50b) is followed by a pointed arch (50c) shorter than the shorter pointed arch (50b), and the pointed arch (50c) is again followed by a high pointed arch (50a).

4. The self-expanding vascular implant (10) according to any one of claims 1 to 3, characterized in that: A distance z1 between a first vertex (26a) of at least one support spring (15, 16, 17, 18, 19; 20) and a first lowest point (28a) following the first vertex (26a) in the circumferential direction is different from a distance z2 between the first lowest point (28a) of the same support spring (15, 16, 17, 18, 19; 20) and a second vertex (26b) following the first lowest point (28a) in the circumferential direction.

5. The self-expanding vascular implant (10) according to any one of claims 1 to 3, characterized in that: It has between 6 and 12 pointed arches (50) facing in the proximal direction x and between 6 and 12 pointed arches (60) facing in the distal direction y.

6. The self-expanding vascular implant (10) according to any one of claims 1 to 3, characterized in that It has at least three support springs (15, 16, 17, 18, 19, 20) which are arranged consecutively one after the other in the longitudinal direction.

7. The self-expanding vascular implant (10) according to any one of claims 1 to 3, characterized in that: It has between three and ten support springs (15, 16, 17, 18, 19, 20) arranged in series one after the other.

8. The self-expanding vascular implant (10) according to any one of claims 1 to 3, characterized in that: The support springs (15, 16, 17, 18, 19, 20) are sewn into the implant material at certain distances from one another.

9. The self-expanding vascular implant (10) according to any one of claims 1 to 3, characterized in that: It is formed as a vascular implant (10) comprising at least one side body branching off from the hollow cylindrical body (24).

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