Thrombectomy Device

Abstract

The present invention relates to a thrombectomy device comprising a substantially cylindrical structure (1), the cylindrical structure (1) having a proximal end and a distal end and comprising a plurality of meshes (3, 4) consisting of a plurality of braces, the thrombectomy device comprising two proximally extending connecting braces (5, 5') disposed on a proximal mesh provided at the proximal end of the cylindrical structure (1), and a connecting member (11) disposed on the proximal side of the cylindrical structure (1), to which the connecting braces (5, 5') are connected, the connecting member (11) being connected to a pusher / insertion wire, the braces of the proximal mesh, the connecting braces (5, 5') and the connecting member (11) and a tensioning brace (9) that may be disposed between the proximal mesh form a closed ring structure (6), the ring structure (6) comprising an annular marker (12) having a radiopaque material for identifying the spatial position of the ring structure (6). The present invention allows visualization of the opening behavior of the thrombectomy device upon release from the catheter and the orientation of the device within the vessel.

Description

[Technical Field]

[0001] The present invention relates to a thrombectomy device with improved marking of the proximal section. The thrombectomy device comprises a substantially cylindrical structure, the proximal end of which is connected to a linking member via a connecting brace. The thrombectomy device is specifically designed for removing thrombi located within the cerebral vasculature. [Background technology]

[0002] Thromboembolic events, such as myocardial infarction, pulmonary embolism, peripheral embolism, and organ thrombosis, are generally caused by thromboemboli (hereafter simply referred to as thrombi or clots), i.e., viscoelastic blood clots composed of platelets, fibrinogen, clotting factors, etc., that lodge within a blood vessel and completely or partially occlude it. Occlusion of an organ artery also leads to the interruption of oxygen and nutrient supply to dependent tissues. Functional metabolic disturbances with loss of function are quickly followed by structural metabolic failures that result in destruction (infarction) of the affected tissue. The organs most commonly affected in this manner are the heart and brain. However, these abnormalities also affect the arteries of the limbs and pulmonary arteries. Furthermore, venous thrombosis and thromboembolic obstruction frequently occur in the veins of the lower extremities and pelvis. The clinical picture of thrombotic obstruction of an intracranial sinus can lead to severe intracerebral hemorrhage due to insufficient venous return to brain tissue.

[0003] In view of the seriousness of the clinical picture and morbidity associated with thromboembolism, different techniques aimed at dissolving or removing thrombi have been developed.

[0004] Apart from treatment with thrombolytic drugs designed to dissolve blood clots and open surgical intervention to remove them, minimally invasive forms of vascular treatment are increasingly being used.

[0005] One of these known forms of treatment involves the use of what is known as a thrombectomy device. Patent Document 1 describes such a thrombectomy device, which has a cylindrical structure with multiple meshes, similar to those found in vascular stents. The cylindrical structure, essentially similar to known stent structures, includes two connecting braces that terminate within a connecting member and are connected to a pusher wire via the connecting member. The pusher wire allows for precise placement of the thrombectomy device at the treatment site. The connecting member is located at the proximal end of the device and connects the proximal end to the distal end of the pusher wire.

[0006] Known thrombectomy devices have slits arranged in a cylindrical, tubular structure that extend in a coiled or spiral fashion around the circumference. Such thrombectomy devices can be manufactured, inter alia, from tubing by laser cutting, although alternative manufacturing methods, for example via intertwined filaments or wires, are also possible.

[0007] The periphery of the cylindrical structure remains open in the area of ​​the slit, which allows the diameter of the cylindrical structure to adapt to some extent to the diameter present at the treatment site, i.e. the lumen of the blood vessel.

[0008] To fixate and apply a predetermined amount of tension to the cylindrical structure with the slit, a tensioning clip or tensioning brace is used to span the slit at the proximal end of the cylindrical structure, thereby producing a circumferentially closed overall structure that is closed at the proximal end, and the cylindrical structure is further provided with a spiral slit on the distal side. The tensioning clip increases the radial force of the cylindrical structure in the proximal region and also serves to maintain the opposing edges of the slit in a predetermined position relative to each other.

[0009] When the term "proximal" is used herein in connection with the present invention, it refers to the end of the device that faces the person administering the procedure when the device is inserted into the patient's body, whereas the term "distal" refers to the end of the device that faces away from the person administering the procedure.

[0010] The proximal region of the known thrombectomy device, which includes a slit, forms a closed ring structure extending from the tensioning clip through the proximal mesh brace and connecting brace to the connecting member. This closed ring structure can also be achieved at the proximal end without the slit, but in this case, a tensioning clip spanning the slit is not required. The ring structure is tilted or inclined relative to the longitudinal axis of the cylindrical structure. In other words, the (approximate) plane formed by the ring structure is oblique to the longitudinal axis of the cylindrical structure and extends from the proximal to the distal end.

[0011] In either case, to achieve optimal functionality of the thrombectomy device, it is extremely important that the ring structure opens wide enough at the treatment site and does not contract, or at least not contract disproportionately, even during retraction of the device.

[0012] Only a sufficiently wide open proximal end allows the device to successfully remove the thrombus. To achieve this, a device that allows the person performing the procedure to assess the three-dimensional state of the proximal ring structure during the intervention is desirable. Such assessment or appraisal is paramount to the success of the procedure, both during insertion of the thrombectomy device and during retraction of the thrombectomy device.

[0013] Assistance in assessment or identification during intervention can be provided by X-ray visible or radiopaque markers. Markers of this nature have long been known in the field of medical implants and devices, such as stents and catheter balloons. Suitable markers are usually applied at specific points, for example, to mark the proximal and distal ends of the stent or catheter, or, in the case of bifurcated implants, specific regions or areas of the stent or catheter, such as fenestrations.

[0014] However, known markers are not suitable for the necessary assessment of the opening behavior or opening of the proximal ring structure of a thrombectomy device because, due to their mainly point-like attachment, they can only provide insufficient information about the spatial state of the ring structure. Furthermore, known markers negatively affect the functionality required for thrombus removal, i.e., the shear force of the device.

[0015] However, since it is especially the proximal section of the thrombectomy device that is crucial for successful thrombus removal, it is crucial to have very accurate information regarding the open state of the ring structure during each step of the intervention. Indeed, it should be noted that successful removal of a thrombus from a blood vessel essentially depends on the requirement that the device, especially the proximal ring structure, have the best possible contact with the vessel wall, since this is the only way to detach the thrombus from the vessel wall. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] International Publication No. 2012 / 156069 Summary of the Invention [Problem to be solved by the invention]

[0017] It is therefore an object of the present invention to provide a thrombectomy device with radiopaque markings that allow the person performing the procedure to assess and evaluate the three-dimensional condition of the annular structure, particularly the proximal annulus, during the intervention without compromising the functionality of the device. [Means for solving the problem]

[0018] This object is achieved, according to the present invention, by a thrombectomy device comprising a substantially cylindrical structure, the cylindrical structure having a proximal end and a distal end and comprising a plurality of meshes consisting of a plurality of braces, the thrombectomy device further comprising two connecting braces arranged on the mesh proximal to the proximal end of the cylindrical structure and extending in the proximal direction, and a connecting member arranged on the proximal side of the cylindrical structure, to which the connecting braces are connected, the connecting member being connected to an insert or pusher wire, the braces of the proximal mesh, the connecting brace and the connecting member, and a tensioning brace that may be arranged between the proximal mesh form a closed ring structure, the ring structure comprising an annular marker having a radiopaque material for identifying the spatial position of the ring structure.

[0019] The thrombectomy device proposed by the present invention comprises a substantially cylindrical structure having a proximal end and a distal end, the cylindrical structure being formed by a plurality of meshes. Although the cylindrical structure is essentially a typical stent, the thrombectomy device serves a different purpose.

[0020] The substantially cylindrical structure of the thrombectomy device has a plurality of openings distributed around its circumference, which are referred to in the context of the present invention as a mesh. In other words, a lattice or mesh structure made up of braces is formed such that a plurality of openings or meshes are formed around the circumference of the basic cylindrical structure. Other regions of the thrombectomy device, particularly the proximal section proximally adjacent to the cylindrical structure, may have a lattice structure with openings formed by the braces, and the diameter of the proximal section typically decreases in the proximal direction, and therefore the proximal section is not cylindrical.

[0021] At the proximal end of the cylindrical structure, two connecting braces are placed on the (usually different) mesh. These connecting braces terminate in a connecting member to which a pusher wire is attached for positioning the device. A proximal marker may be provided in the area of ​​the connecting member, and a distal marker may be located at the distal end of the device. The proximal and distal markers may comprise known radiopaque materials, as described below.

[0022] A detachment point may be provided on the connecting member or in the area of ​​the pusher wire so that the cylindrical structure can be detached if necessary. However, since for thrombectomy purposes the thrombectomy device is primarily intended to be withdrawn from the vasculature, a detachment point is not strictly necessary, but rather simply serves to detach if the thrombectomy device cannot be retracted. The detachment point may be, for example, an electrolytic corrosion system that allows the cylindrical structure to detach from the insertion / pusher wire. Other detachment methods, such as mechanical, thermal, or chemical release mechanisms, are known to those skilled in the art.

[0023] Optionally, the slits may be arranged to extend helically around the circumference of the cylindrical structure, with one tensioning brace, which may also be called a tensioning clip, spanning the slits at the proximal end of the cylindrical structure.

[0024] At least some of the braces, connecting braces and linking members of the proximal mesh together form a closed ring structure, and thus the ring structure is formed by the associated braces, connecting braces and linking members of the proximal mesh.

[0025] If the thrombectomy device is provided with a slit, the tensioning brace spanning the slit at the proximal end of the cylindrical structure also forms part of the ring structure, i.e., the tensioning brace, some braces of the proximal mesh, the connecting brace, and the linking member together form a closed ring structure.

[0026] As proposed by the present invention, the ring structure includes at least one annular marker arranged on the ring structure such that the marker can indicate the spatial position or orientation of the ring structure during the intervention, thus allowing the user to assess the open state of the ring structure. The marker of the ring structure will be referred to hereinafter as the "annular marker" to distinguish it from the separate distal and proximal markers. Because the ring structure typically extends obliquely through the lumen of the blood vessel, the annular marker also allows the treating physician to visualize the orientation of the thrombectomy device about its longitudinal axis.

[0027] In a preferred embodiment, the annular marker comprises a radiopaque material, such as gold, platinum, palladium, tantalum, or suitable combinations based on precious metals or possible alloys and combinations such as platinum-iridium. Such radiopaque materials may also be used for other markers on the thrombectomy device.

[0028] Preferably, the annular marker is wire-like. It is also preferred that the annular marker is provided as a unitary element, i.e. that the annular marker comprises a continuous wire.

[0029] The wire itself may comprise a plurality of individual strands that are, for example, braided, intertwined, twisted or otherwise connected. Thus, according to the present invention, the wire may be of stranded design. Within the meaning of the present invention, an annular marker formed from a continuous wire should be understood as meaning that the wire, or the annular marker, is not interrupted along its length.

[0030] The wire-like annular marker is preferably wrapped around the brace to form a ring structure, but alternatively the annular marker may be located on only one side of the ring structure, for example on the inside or outside, or the annular marker may simply be wrapped around the ring structure one or several times.

[0031] It may be advantageous for the annular marker to wrap around the entire length of the ring structure, i.e., starting for example from the connecting member or from the proximal marker, through the first connecting brace and the proximal mesh brace, towards the tensioning brace if one is located, and then through the proximal mesh brace and the second connecting brace back to the connecting member or proximal marker.

[0032] The end of the annular marker is preferably fixed to the proximal marker or the connecting member.

[0033] In alternative embodiments, placement of the annular markers may be limited to only one or more portions of the ring structure, such as the tensioning brace and / or connecting brace and / or proximal mesh brace, but again, it is desirable for the annular markers to outline the ring structure to the extent that the deployment and orientation of the ring structure as a whole can be derived based on visualization with appropriate imaging techniques.

[0034] It is therefore conceivable that the annular marker is made up of a number of individual annular marker elements.

[0035] Apart from being provided in the form of a wire, the annular marker and annular marker elements may have other shapes, for example, spiral, tubular or sleeve-like structures.

[0036] In another embodiment, additional markers are provided that are located at predetermined positions along the cylindrical structure, for example in the central region, and these markers may likewise be of continuous design or comprise multiple marker elements, for example in the form of wires, spirals, tubes or sleeves.

[0037] The cross-section of the wire-like annular markers and other markers is preferably circular, although embodiments featuring oval or bent wires are also contemplated.

[0038] Preferably, the diameter of the wire is in the range of 0.01 mm to 0.5 mm, and the edge length of the wire is in the range of 0.01 mm to 0.5 mm.

[0039] The attachment of the annular marker or annular marker element and of the markers or marker elements is effected by known methods, in particular by welding (for example by laser), crimping, clamping or adhesive / bonding.

[0040] In addition to the markers described above, in another embodiment of the present invention, it is contemplated that additional markings may be provided by coating at least a portion of the cylindrical structure, e.g., the proximal, distal, or central region, with a radiopaque material. Suitable coating materials are substantially the same as the materials, alloys, and combinations previously described as suitable for the other markers. For example, a gold coating may be applied.

[0041] The thrombectomy device of the present invention can be implemented in a variety of ways: the underlying concept of placing an annular marker along the proximal ring structure is easily transferable to similar devices.

[0042] The tensioning brace may be attached to the cylindrical structure afterwards, or it may form part of the structure itself, for example being cut from the tube together with the structure.

[0043] The proximal clip in the form of a tensioning brace improves the radial force characteristics of the cylindrical structure in the proximal region. In particular, the provision of this clip reduces not only the narrowing of the cylindrical structure but also the tensile stresses that arise when the device is retracted into the catheter. At the same time, an additional stripping effect is created, similar to that achieved by the mesh and edges of the cylindrical structure.

[0044] However, of particular importance is the improved deployment force in the proximal region, which allows the cylindrical structure to optimally fit the vessel lumen, while at the same time preventing the regions of the cylindrical structure separated by the slits from shifting relative to one another.

[0045] To allow for easy retraction of the cylindrical structure into the catheter, the arched curve of the tensioning brace is configured so that its apex points toward the distal end of the cylindrical structure, i.e., the curved portion of the tensioning brace is closed distally, while proximally it forms a ring structure with the connecting brace and the proximal mesh brace that terminates within the linking member.

[0046] Alternatively, the tensioning brace spans a slit in the cylindrical structure in a wavy manner, for example, such that the tensioning brace follows the edge configuration of the mesh structure from one side of the slit to the other. According to a variation of the invention, the cylindrical structure of the invention may be occluded at its distal end by a mesh structure intended to collect thrombus material therein, such as when a capture basket is used.

[0047] The mesh structure of the cylindrical structure may be woven, i.e., composed of individual wires or wire strands, or preferably a cut-out structure, for which a tube of appropriate diameter is used and the mesh structure is cut out of the tube with a laser. The material is typically metal, but plastic materials can also be employed. The elasticity of the material must be sufficient to allow contraction appropriate for the diameter of a conventional catheter, and furthermore, cause expansion to the desired and predefined diameter upon release from the catheter. Furthermore, it may be advantageous to treat the lattice structure by electropolishing to make it smoother and rounder, thus making it less traumatic. This also reduces the risk of bacteria or other impurities adhering to the structure. The struts or wires may have a circular, oval, square, rectangular, or trapezoidal cross-section, with the edges of the square, rectangular, or trapezoidal cross-section advantageously rounded. Thin braces / wires in the form of thin strips, particularly metal strips, may also be employed.

[0048] Besides iron alloys (stainless steel, spring steel) and cobalt-chromium alloys, shape-memory alloys, such as binary nickel-titanium alloys (nitinol) and ternary nickel-titanium-chromium alloys (chromium-doped alloys), are particularly suitable for use as brace materials. Nitinol, in particular, is known for its application in self-expanding structures in the neurovascular field.

[0049] In addition to the proximal tensioning brace, a suitable thrombectomy device may be provided with separate tensioning clips in the central and distal regions, although the tensioning clips may be omitted altogether if a shape-memory material capable of exhibiting sufficient shape recovery effect is used.

[0050] The thrombectomy device is delivered to the site of use using a catheter and released within the thrombus itself, adjacent to the thrombus, or distal to the thrombus. The device expands within the blood vessel and conforms to the vessel lumen. As soon as the device is deployed, or as the device is retracted, thrombus material becomes entangled within the mesh structure and is carried into the catheter as the device is retracted. Clot debris still attached to the vessel wall is dislodged and carried away along the edges of the slits by the shearing action of the mesh. The clot is drawn into the catheter and extracted from the body when the catheter is removed.

[0051] By using another catheter, in particular an aspiration catheter, additionally broken down particles of the thrombus can be aspirated, minimizing the risk of further embolism that may be caused by these particles.

[0052] During clot extraction, the helical arrangement of slits across the periphery offers the particular advantage that the edges of the cylindrical structure along the slits move tangentially around the vessel wall during retraction, improving the shearing effect. Furthermore, the helical or coiled arrangement of slits improves (reduces) bending stiffness to the extent that the device can better conform to tortuous vascular patterns, facilitating both device positioning and clot extraction from complex vascular structures.

[0053] As previously described, the cylindrical structures of the present invention are preferably cut from a cylindrical tube using a laser. This method allows individual meshes to be provided with specific cross sections, such as square, rectangular, or trapezoidal. In the case of rectangular and trapezoidal shapes, the narrow side of the cross section may be located on the outer periphery, or the long side may be located on the outer periphery. However, it is preferred that the narrow side of the rectangular shape, and particularly the trapezoidal shape, faces the vessel wall, which allows thrombus to more easily penetrate into the mesh structure and efficiently displace the clot when the cylindrical structure is expanded.

[0054] A connecting brace, located at the proximal end of the cylindrical structure, extends from the proximal mesh adjacent the slit to and joins the connecting member, which forms part of the cylindrical structure and, as such, is typically constructed from the same material.

[0055] The present invention will be further illustrated by way of example with reference to the accompanying drawings. The drawings show variations of the preferred embodiments of the present invention, but it should be noted that the present invention itself is not limited to these variations. The present invention also includes, so far as it is technically significant, any combination of the technical features particularly recited in the claims or the specification as being relevant to the present invention. The present invention will be clarified by the following drawings. [Brief explanation of the drawings]

[0056] [Figure 1] 1 is a three-dimensional view of a known cylindrical structure; [Figure 2] 1 is a three-dimensional view of a preferred embodiment of the device according to the invention; DETAILED DESCRIPTION OF THE INVENTION

[0057] 1 shows a three-dimensional view of a variation of a known cylindrical structure 1, preferably with differently designed meshes 3, 4 and connecting braces 5 and 5'. The meshes 3, 4 give stability and flexibility to the whole structure.

[0058] A slit 7 extends through the cylindrical structure 1 and is spanned by a tensioning brace 9 at the proximal end of the cylindrical structure 1. The slit 7 is defined by edges 10 and 10' of a mesh structure. The slit 7 preferably extends obliquely relative to the longitudinal axis of the cylindrical structure 1, which is illustrated in a three-dimensional view as a helical extension along the periphery.

[0059] The brace of the cylindrical structure 1 located on the rear side of the cylindrical structure 1 is shown in a lighter color. It can be seen that a slit 7 is located at the proximal end of the cylindrical structure 1, passing under the tensioning clip 9 and spiraling to the right around the circumference of the cylindrical structure 1. Distally, the slit 7 terminates at the underside of the cylindrical structure 1, thus having a rotation / wrap of approximately 180°.

[0060] The connecting braces 5, 5' are joined in a single connecting member 11, via which the connection to the pusher wire, which is only suggested in FIG. 1, is made.

[0061] A proximal marker 13 is provided in the region of the connecting member 11 and indicates the proximal end of the cylindrical structure 1 .

[0062] A tensioning brace 9 spans the slit 7. The tensioning brace 9 is attached to the mesh 3, which is located at the edges 10, 10' of the mesh structure, and the arc of the tensioning brace 9 points toward the distal side of the cylindrical structure 1. This allows the cylindrical structure 1 to be easily retracted into the catheter.

[0063] In a preferred embodiment, the tensioning brace 9 can follow the shape of the side or edge 10 of the mesh structure with its wavy shape, continuing this shape to the oppositely disposed edge 10'. However, alternatively, the tensioning brace 9 can have a simple arched shape, i.e., a non-wavy shape.

[0064] The connecting braces 5, 5' together with the adjacent mesh edges and the tensioning brace 9 form a kind of loop similar to the opening of a capture basket, which facilitates the retraction of the thrombectomy device into the catheter and is further suitable for shearing off any clots or clot remnants adhering to the vessel wall.

[0065] The connecting braces 5, 5', the mesh edges adjacent to the connecting braces 5, 5' and the tensioning brace 9 together with the linking member 11 form a ring structure.

[0066] The distal end of the cylindrical structure may additionally be closed by a mesh structure.

[0067] FIG. 2 illustrates a device proposed by the present invention, in which an annular marker 12 is provided along the proximal ring structure 6. In the preferred embodiment shown, the annular marker 12 comprises a wire-like radiopaque material that is looped around the entire circumference of the ring structure 6. Preferably, the wire-like annular marker 12 is provided as a unitary element and thus comprises only a single, continuous wire. The wire itself may comprise, for example, multiple individual strands braided, intertwined, twisted, or otherwise connected to one another. Thus, according to the present invention, a wire-like annular marker 12 made of a continuous wire is an annular marker 12 that is uninterrupted along its length, i.e., provided as a single, unitary element.

[0068] The end of the annular marker 12 is fixed in or on the proximal marker 13 .

[0069] Additional proximal markers 13 and distal markers 2 may be provided.

[0070] In the drawings, like reference numbers are meant to refer to like objects. [Explanation of symbols]

[0071] 1 Cylindrical structure 2 distal marker 3,4 mesh 5.5' Connecting Brace 6 ring structure 7 Slit 9 Tensioning Brace 10 mesh edge 11 Connecting member 12 Annular Markers 13 Proximal Marker d. distal p proximal

Claims

1. A thrombectomy device comprising a substantially cylindrical structure (1), said cylindrical structure (1) having a proximal end and a distal end and comprising a plurality of meshes (3, 4) made up of a plurality of braces, said thrombectomy device comprising: - two connecting braces (5, 5') arranged on the proximal mesh at the proximal end of the cylindrical structure (1) and extending in the proximal direction; a connecting member (11) located proximally of said cylindrical structure (1), to which said connecting braces (5, 5') are attached, said connecting member (11) being connected to an inserter / pusher wire; Including, A thrombectomy device, wherein the proximal mesh brace, the connecting braces (5, 5') and the linking member (11) and a tensioning brace (9) disposed between the proximal mesh form a closed ring structure (6), 1. A thrombectomy device, characterized in that the ring structure (6) is provided with an annular marker (12) having a radiopaque material for visualizing the spatial position of the ring structure (6), and additional markings on at least a portion of the cylindrical structure (1) are provided by coating with a radiopaque material.

2. 2. The thrombectomy device according to claim 1, characterized in that the cylindrical structure (1) has a slit (7) extending in a spiral or coil shape around its periphery, and a tensioning brace (9) straddles the slit (7) at the proximal end of the cylindrical structure (1).

3. 3. The thrombectomy device according to claim 1 or 2, characterized in that the annular marker (12) at least partially surrounds the ring structure (6) along its length.

4. 4. The thrombectomy device according to claim 3, characterized in that the annular marker (12) surrounds the ring structure (6) along its entire length.

5. 5. The thrombectomy device according to any one of claims 1 to 4, characterized in that the annular marker (12) is wire-like or sleeve-like and is wrapped or placed around the brace forming the ring structure (6).

6. Thrombectomy device according to claim 5, characterized in that the annular wire marker (12) is an annular marker of one-piece design.

7. Thrombectomy device according to any one of claims 1 to 6, characterized in that a proximal marker (13) is provided in the region of the connecting member (11).

8. 8. The thrombectomy device according to claim 7, characterized in that the end of the wire-shaped annular marker (12) is fixed within or relative to the proximal marker (13) or the connecting member (11).

9. 9. The thrombectomy device according to any one of claims 1 to 8, characterized in that the tensioning brace (9) forms a curved portion, the apex of which points towards the distal end of the cylindrical structure (1).

10. 10. The thrombectomy device according to claim 1, further comprising a distal marker and / or a proximal marker made of a radiopaque material.

11. 11. The thrombectomy device according to any one of claims 1 to 10, characterized in that the radiopaque material is selected from gold, tantalum, platinum, palladium or alloys based on precious metals or combinations of these materials such as platinum-iridium.

12. 12. The thrombectomy device according to any one of claims 1 to 11, characterized in that further markers are provided along the cylindrical structure (1), which markers may be in the form of wires, spirals, tubes or sleeves.

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