Mechanical thrombectomy apparatus

Abstract

A mechanical thrombectomy apparatus is provided. The mechanical thrombectomy apparatus may comprise a support wire, and a thrombectomy device provided with an expandable frame that connects to the support wire. The expandable frame may comprise: a proximal portion in which a first plurality of cells of the expandable frame are interconnected; and a distal portion in which a second plurality of cells of the expandable frame are at least partially separated from each other.

Description

mechanical thrombectomy device

[0001] The present invention relates to a thrombus removal device, and more particularly, but not exclusively, to a mechanical thrombus removal device used for removing thrombi in blood vessels.

[0002] Various methods exist to treat thrombosis in specific blood vessels within the body. Among these, mechanical thrombectomy devices are inserted into blood vessels to break up or remove the clot, restoring perfusion through the occluded vessel. Approved mechanical thrombectomy devices for this purpose include thrombus filters, thrombus aspiration devices, coil retrievers, and, more recently, stent retrievers.

[0003] Stent retriever devices are primarily used to remove acute thrombi in stroke patients. They involve deploying a self-expanding stent, typically made of wire mesh, into a blood vessel to capture the thrombus. The stent retriever then pulls on the supporting wire, allowing the clot to be retrieved from the patient. These devices require fluoroscopic visibility and the ability to capture, confine, or maintain the thrombus without damaging the narrow, tortuous vascular structure. Furthermore, they must not pose a risk during surgery.

[0004] The existing stent retriever device, which has a cylindrical structure in which all cells of the stent are directly connected, has a problem in that when inserted into a narrow blood vessel and the expandable frame structure can no longer be compressed, the radial force of the expandable frame structure increases rapidly, causing unwanted damage to the blood vessel tissue.

[0005] In addition, the conventional stent retriever device with a cylindrical structure in which all cells of the stent are open had safety issues because the thrombus removal device was unnecessarily stretched and the captured thrombus was lost when the stent retriever device was moved through a narrow and tortuous blood vessel, or the fatigue of the device increased due to repeated excessive tensile deformation.

[0006] The radial profile of existing stent retriever devices was constant throughout the device and could not be adjusted, which could cause damage to delicate tissues such as narrow blood vessels or reduce the durability of the device due to excessive repetitive stretching.

[0007] One object of the present invention to solve the above-mentioned problems is to provide a mechanical thrombectomy device in which the cells of the expandable frame of the thrombectomy device have a distal portion that is at least partially separated, so that the radial profile of the stent retriever device can be adjusted.

[0008] Another object of the present invention to solve the above-mentioned problem is to provide a mechanical thrombectomy device having an extendable frame of the thrombectomy device with a proximal portion that is connected to each other while the radial profile can be adjusted, thereby providing excellent transmission of the propulsive or traction force of the stent retriever device and also having an axial extension that can be adjusted.

[0009] However, the problem to be solved by the present invention is not limited thereto, and may be expanded in various ways without departing from the spirit and scope of the present invention.

[0010] According to one embodiment of the present invention for achieving the above-described object, a thrombectomy device is a mechanical thrombectomy device, comprising: a support wire; and a clot arrestor connected to the support wire and having an expandable frame; wherein the expandable frame may include a proximal portion in which a first plurality of cells of the expandable frame are connected to each other; and a distal portion in which a second plurality of cells of the expandable frame are at least partially separated from each other.

[0011] According to one aspect, the first plurality of cells are connected by a connecting bridge interconnecting the respective cells, and the second plurality of cells can form a branch bridge with each of the separated cells of the distal portion.

[0012] According to one aspect, the expandable frame of the proximal portion comprises a ring of frame cells, the ring of frame cells being formed by a support strut which is part of a first plurality of cells connected to each other, one end of the support strut being attached to the support wire and the other end being connected to the connecting bridge, so as to mechanically support the expandable frame.

[0013] According to one aspect, when the thrombectomy device is moved through a curved blood vessel, the tensile strain of the first plurality of cells may be less than the tensile strain of the second plurality of cells.

[0014] According to one aspect, the distal portion may have an adjustable radial profile.

[0015] According to one aspect, the distal portion may be deformable such that, when placed in free space, a radial plane of the distal portion becomes wider than a radial plane of the proximal portion, and when introduced into a blood vessel, a radial plane of the distal portion becomes narrower than a radial plane of the proximal portion.

[0016] According to one aspect, the branch bridge can branch in the longitudinal direction of the expandable frame.

[0017] According to one aspect, the branch bridge can branch radially of the expandable frame.

[0018] According to one aspect, the branch line connecting the branch points of the branch bridge may be a straight line longitudinally along the expandable frame.

[0019] According to one aspect, the branch line may include a plurality of straight lines having different lengths.

[0020] According to one aspect, at least two of the plurality of straight lines can be arranged in a direction symmetrical to each other with respect to the longitudinal axis.

[0021] According to one aspect, the expandable frame may further include a branch line branching laterally at least partially from the longitudinal direction.

[0022] According to one aspect, the branch portions of the branch bridge may at least partially overlap each other.

[0023] According to one aspect, the branch bridges may be at least partially spaced apart from each other longitudinally or radially with cells interposed therebetween along the expandable frame of the distal portion.

[0024] According to one aspect, the branch line connecting the branch points of the branch bridge may be spiral along the circumference of the expandable frame of the distal portion.

[0025] According to one aspect, the branch lines connecting the branch points of the branch bridge may be longitudinally wavy along the expandable frame of the distal portion.

[0026] According to one aspect, the branch bridge can be ground or tapered to form a smooth edge.

[0027] According to one aspect, the longitudinal length of the proximal portion and the longitudinal length of the distal portion may be different from each other.

[0028] According to one aspect, the ratio of the longitudinal lengths of the proximal portion and the distal portion may be determined differently depending on the target blood vessel for insertion of the mechanical thrombectomy device.

[0029] According to one aspect, the expandable frame can be formed by laser cutting a shape memory alloy tube.

[0030] The disclosed technology may have the following effects. However, this does not mean that a particular embodiment must include all or only the following effects, and thus the scope of the disclosed technology should not be construed as being limited thereby.

[0031] According to the mechanical thrombus removal device according to one embodiment of the present invention described above, since the thrombus remover includes a proximal portion that is connected to each other and a distal portion that is at least partially separated, the radial force of the mechanical thrombus removal device can be partially varied, so that a mechanical thrombus removal device with excellent structural support can be provided while causing less damage to delicate blood vessels.

[0032] In addition, the mechanical thrombus removal device according to the embodiment of the present invention described above can partially adjust the radial profile of the mechanical thrombus removal device differently, thereby providing a mechanical thrombus removal device that can penetrate deep into complex and narrow blood vessels and prevent excessive tensile deformation, thereby providing a stable and excellent thrombus removal device.

[0033] FIG. 1 is a plan view of a mechanical thrombus removal device according to one embodiment of the present invention.

[0034] FIG. 2 is a plan view of a thrombus remover according to one embodiment of the present invention.

[0035] FIG. 3 is an enlarged view of a connecting bridge according to one embodiment of the present invention.

[0036] FIG. 4 is an enlarged view of a branch bridge according to one embodiment of the present invention.

[0037] FIG. 5 is a partial view of a proximal portion of a thrombus remover according to one embodiment of the present invention.

[0038] FIG. 6 is a drawing for explaining a branch bridge according to one embodiment of the present invention.

[0039] FIG. 7 is a drawing for explaining a branch bridge according to one embodiment of the present invention.

[0040] FIG. 8 is a drawing for explaining the arrangement of a branch bridge according to one embodiment of the present invention.

[0041] FIG. 9 is a drawing for explaining another arrangement of a branch bridge according to one embodiment of the present invention.

[0042] FIG. 10 is a drawing for explaining another arrangement of a branch bridge according to one embodiment of the present invention.

[0043] FIG. 11 is a drawing for explaining another arrangement of a branch bridge according to one embodiment of the present invention.

[0044] FIG. 12 is a drawing for explaining another arrangement of a branch bridge according to one embodiment of the present invention.

[0045] FIG. 13 is a drawing for explaining another arrangement of a branch bridge according to one embodiment of the present invention.

[0046] FIG. 14 is a drawing showing a branch bridge shape and a radial profile of a distal portion thereof according to one embodiment of the present invention.

[0047] FIG. 15 is a drawing showing another form of a branch bridge and a radial profile of the distal portion thereof according to one embodiment of the present invention.

[0048] FIG. 16 is a drawing illustrating another form of a branch bridge and a radial profile of the distal portion thereof according to one embodiment of the present invention.

[0049] The present invention can be modified in various ways and has various embodiments, and specific embodiments are illustrated in the drawings and described in detail.

[0050] However, this is not intended to limit the present invention to a specific embodiment, but should be understood to include all modifications, equivalents, or substitutes included in the spirit and technical scope of the present invention.

[0051] While terms such as "first" and "second" may be used to describe various components, these components should not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a "second component," and similarly, a second component may also be referred to as a "first component." The term "and / or" includes any combination of multiple related items described herein or any item among multiple related items described herein.

[0052] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0053] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprise" or "have" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0054] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0055] Hereinafter, with reference to the attached drawings, preferred embodiments of the present invention will be described in more detail. In order to facilitate an overall understanding in describing the present invention, identical reference numerals will be used for identical components in the drawings, and redundant descriptions of identical components will be omitted.

[0056]

[0057] As previously discussed, the conventional stent retriever device had a structure in which all cells of the stent were directly connected or entirely separated, so that the radial force of the expandable frame of the thrombus remover could not be partially varied, and accordingly, there was a problem that if the radial force increased rapidly, it could cause damage to the vascular tissue, and if the reciprocal force was too small, the thrombus remover was excessively stretched and could not effectively remove the thrombus, and there was a problem with the durability of the device due to repeated excessive tensile deformation.

[0058]

[0059] A mechanical thrombus removal device according to one embodiment of the present disclosure is intended to solve the above-described problems, and can improve the durability of the mechanical thrombus removal device by forming the proximal part of the thrombus remover with interconnected cells to provide structural support for repetitive tensile deformation, and can prevent damage to delicate vascular tissue by forming the distal part of the thrombus remover with partially separated cells to prevent abrupt changes in radial force.

[0060]

[0061] Below, a mechanical thrombus removal device according to one embodiment of the present invention will be described in more detail with reference to the drawings.

[0062]

[0063] Hereinafter, the term 'thrombus remover' in this description may refer to, for example, a part of a general stent retriever that includes a stent, but is not limited to a conventional stent retriever, and should be understood to include all components necessary to remove coagulated blood within a blood vessel and restore perfusion.

[0064] Additionally, the term 'expandable frame' in this description hereinafter shall be understood to mean a frame that is initially maintained in a compressed state and can be expanded after being moved to an appropriate location, and may be applied in any form known in the art.

[0065] Additionally, the use of relative terms throughout the description of the invention herein may indicate relative positions or directions. For example, "distal" may indicate a first direction along the longitudinal axis of the support wire or thrombectomy device. Similarly, "proximal" may indicate a second direction opposite to the first direction. However, these terms are provided to establish relative references and are not intended to limit the use or orientation of the mechanical thrombectomy device to any particular configuration described in the various embodiments below.

[0066]

[0067] FIG. 1 is a plan view of a mechanical thrombus removal device (1) according to one embodiment of the present invention. As illustrated in FIG. 1, the mechanical thrombus removal device (1) according to one embodiment may include, for example, a support wire (10) and a thrombus remover (20).

[0068] A mechanical thrombectomy device (1) is an endovascular tool that can be used to treat acute ischemic stroke. The mechanical thrombectomy device (1) includes a proximal control region that allows an operator to advance, withdraw, and rotate a distal working region of the device. More specifically, the mechanical thrombectomy device (1) includes a support wire (10) that an operator can push to advance the distal working region, pull to withdraw the distal working region, or rotate to rotate the distal working region. In one embodiment, the support wire (10) can be a flexible elongated wire formed of a resilient material, such as stainless steel or a superelastic nickel titanium alloy.

[0069] A mechanical thrombectomy device (1) may include a thrombectomy device (20) that can be advanced through a microcatheter and deployed from the microcatheter into a target tissue. When deployed within the target tissue, the thrombectomy device (20) may capture, entrap, bind, or mechanically integrate with the thrombus. The bound thrombus may be retrieved from the patient by traction on the thrombectomy device (20) and a support wire (10) to retrieve the thrombus from the vascular structure.

[0070] The clot remover (20) can be sized and shaped to provide respective degrees of clot binding, clot capture, flexibility, or any other performance characteristic. The clot remover (20) is connected distally to the support wire (10) and can include an expandable frame (100). The expandable frame (100) is a generally elongated cylindrical frame structure capable of capturing and confining a clot within the interior of the cylindrical shape, and has flexibility, shape memory, and contraction functions and can be made of a shape memory alloy material including a nickel titanium alloy. The size and shape of each cell of the expandable frame (100) can be determined according to the performance characteristics of the clot remover as described above. The expandable frame (100) of the thrombus remover (20) can be formed by laser-cutting a cylindrical shape memory alloy tube into a three-dimensional expandable structure, or by mechanical processing, chemical processing, electromechanical processing, electric discharge processing, and various other methods known in the art, and accordingly, the expandable frame (100) of the thrombus remover (20) can have an approximately circular radial profile as illustrated in FIGS. 14 to 16, which will be described later.

[0071] Although not shown in the drawing, the expandable frame (100) may be equipped with a plurality of radiopaque markers. The radiopaque markers may enhance device visibility and provide a cue for the operator to locate a clot relative to the thrombectomy device. The radiopaque markers may include radiopaque markers mounted in a variety of ways, including radiopaque bands, wire coils, plating, welding, coating, etc., which are conventional in the art. Alternatively, the radiopaque material may be plated onto the expandable frame (100). Alternatively, the radiopaque markers may be formed as bands that are crimped onto the expandable frame (100). In one aspect, the radiopaque markers may include coils formed of radiopaque wire, which may be wound or wrapped around the expandable frame (100). In one aspect, the radiopaque markers may have an atraumatic surface that does not damage the vessel wall during use.

[0072]

[0073] FIG. 2 is a plan view of a thrombus remover (20) according to one embodiment of the present invention, FIG. 3 is an enlarged view of a connecting bridge (220) according to one embodiment of the present invention, and FIG. 4 is an enlarged view of a branch bridge (320) according to one embodiment of the present invention.

[0074] First, an expandable frame (100) will be described with reference to FIG. 2. The expandable frame (100) includes a proximal portion (200) in which a first plurality of cells (210) of the expandable frame are connected to each other, and a distal portion (300) in which a second plurality of cells (310) of the expandable frame (100) are at least partially separated from each other. While each of the cells (210, 310) is illustrated as having a pattern that generally includes a sinusoidal shape, the pattern of the cells (210, 310) is not limited thereto, and any shape may be possible depending on the performance characteristics of the thrombectomy device (20).

[0075] The proximal portion (200) may refer to a portion starting from the most proximal end of the thrombectomy device (20) connected to the support wire (10) illustrated in FIG. 1 to a point where the first plurality of cells (210) of the longitudinally expandable frame (100) are connected to each other. In addition, the distal portion (300) may refer to a portion starting from a point where the proximal portion (200) ends to a most distal end of the thrombectomy device (20) to a point where the second plurality of cells (310) of the longitudinally expandable frame (100) are at least partially separated from each other.

[0076] The first plurality of cells (210) of the proximal portion (200) are connected by a connecting bridge (220) that interconnects each cell (210), and the second plurality of cells (310) of the distal portion (300) are separated such that each cell (310) can form a branch bridge (320). The connecting bridge (220) and the branch bridge (320) are illustrated in enlarged views in FIGS. 3 and 4. Referring to FIG. 3, the connecting bridge (220) according to one aspect may be a straight strut connected to each end of the adjacent first plurality of cells (210), but is not limited thereto, and any connecting structure may be included in the connecting bridge. Referring to FIG. 4, a branch bridge (320) is formed such that the struts forming adjacent second plurality of cells (310) may contact each other but are not directly connected. Any configuration in which the struts of the second plurality of cells (310) do not contact each other may be included in the branch bridge (320). The struts forming the second plurality of cells (310) may branch in a longitudinal direction of the expandable frame (100) diverging from the contact point of each cell (310). In one aspect, the branch bridge (320) may be ground or tapered to form a smooth edge. For example, the branch bridge (320) may be rounded using any known method to form an atraumatic surface that does not damage the vessel surface. The configuration and arrangement of the branch bridge (320) will be described in detail later.

[0077] Although the proximal portion (200) and the distal portion (300) described above are illustrated as having generally similar longitudinal lengths in FIGS. 1 and 2, the longitudinal lengths of the proximal portion (200) and the distal portion (300) may be different from each other in one aspect. In addition, the ratio of the longitudinal lengths of the proximal portion (200) and the distal portion (300) may be determined differently depending on the target blood vessel for insertion of the mechanical thrombectomy device (1).

[0078] For example, when a mechanical thrombectomy device (1) is to be inserted into a relatively narrow and tortuous blood vessel structure, the longitudinal length of the proximal portion (200) is formed short and the longitudinal length of the distal portion (300) is formed long, thereby adjusting the magnitude of the radial force of the distal portion (300) to be small, thereby reducing damage to the blood vessel tissue and delivering the mechanical thrombectomy device (1) to a deeper location in the blood vessel. In addition, when a mechanical thrombectomy device (1) is to be inserted into a relatively wide and uncomplicated blood vessel structure, the longitudinal length of the proximal portion (200) is formed longer than the longitudinal length of the distal portion (300), thereby increasing the overall structural bonding force and support force of the mechanical thrombectomy device (1), thereby enabling more reliable capture and recovery of a thrombus within the blood vessel.

[0079] More specifically, the advantages and disadvantages of a frame having a closed cell structure in which all cells (210) of an expandable frame (100) such as a proximal portion (200) according to one embodiment of the present invention are connected to each other will be described first.

[0080] The advantages of the closed-cell structure are as follows: 1. It can support and maintain stability of the vascular wall by providing strong mechanical support due to the structural connections between the closed cells. 2. Because the closed-cell structure is structurally connected, it is easy to accurately place within the blood vessel and experiences minimal tensile deformation during movement within the blood vessel, making it effective in capturing and retrieving clots.

[0081] Meanwhile, the disadvantages of the closed-cell structure are as follows: 1. The closed-cell structure may have reduced flexibility due to the strong structural connections, which may limit the ability of the thrombectomy device to move naturally with the movement of the vessel. 2. The closed-cell structure may have difficulty dissipating radial forces due to the structural connections between each cell, which may cause a sharp increase in radial forces at certain points and cause damage to the vessel wall. 3. The closed-cell structure may have limited adaptability to the structure of the vessel, such as in the case of special vascular anatomy such as bends or branches of the vessel.

[0082] Now, the advantages and disadvantages of an open cell structure frame, in which the cells (310) of an expandable frame (100), such as the distal portion (300) according to one embodiment of the present invention, are at least partially separated from each other, will be described. An open cell structure frame may have conflicting aspects with a closed cell structure frame.

[0083] The advantages of the open-cell structure are as follows: 1. The open-cell structure can improve the flexibility and flexibility of the thrombectomy device, allowing the thrombectomy device to bend under pressure and move along the natural movement of the blood vessel. 2. The open-cell structure can distribute the pressure between the thrombectomy device and the blood vessel wall, reduce the radial force applied to the blood vessel wall, and provide effective stability without damaging the blood vessel wall.

[0084] Disadvantages of the open-cell structure include: 1. The open-cell structure may not be able to effectively remove a thrombus if it is located in an opening or slit, which may impair blood flow. 2. The open-cell structure may have structural limitations regarding the size and shape of the opening or slit, which may make it difficult to apply to certain vascular anatomy. 3. The open-cell structure may be subject to excessive tensile deformation due to the presence of the opening or slit, which may result in loss of a captured thrombus or difficulty in capturing and removing the thrombus.

[0085] In actual surgical use, when an operator uses only a thrombus removal device having a closed cell structure or only an open cell structure, the success rate or mortality rate of the surgery are similar to each other due to the respective shortcomings of these structures. Therefore, a mechanical thrombus removal device (1) according to an embodiment of the present invention can be configured to include a proximal portion (200) having a first plurality of cells (210) that are connected to each other by an expandable frame (100), and a distal portion (300) having a second plurality of cells (310) that are at least partially separated from each other, in order to complement the advantages and disadvantages of the closed cell structure and the open cell structure. That is, according to an embodiment of the present invention, a mechanical thrombus removal device (1) including a proximal portion having a closed cell structure and a distal portion having an at least partially open cell structure can be provided.

[0086] A mechanical thrombectomy device (1) including a proximal portion of closed cells and a distal portion of open cells may have the following advantages: 1. By providing an open-cell structure at the distal portion of the thrombectomy device (20), the flexibility and pliability of the thrombectomy device (20) can be improved, and the distal portion (300) of the thrombectomy device (20) can bend under pressure and move along the natural movement of the blood vessel, so that it can be inserted more deeply into relatively narrow and tortuous blood vessels compared to a thrombectomy device having only a closed-cell structure. 2. The distal portion (300) of the open-cell structure can distribute the pressure between the thrombectomy device (20) and the blood vessel wall and reduce the radial force applied to the blood vessel wall, thereby providing effective support and stability that do not damage the blood vessel wall. 3. By providing a closed cell structure at the proximal portion (200) of the thrombus remover (20), strong mechanical support is provided due to the structural connection between the closed cells, thereby preventing excessive tension due to openings or slits of the open cell structure and stably supporting the inner wall of the blood vessel. 4. By providing a closed cell structure with excellent mechanical bonding strength at the proximal portion (200) of the thrombus remover (20), deterioration of the durability of the device due to repeated excessive tension can be compensated for.

[0087] However, if the open cell structure is located at the proximal part (200) of the thrombus remover (20) and the closed cell structure is located at the distal part (300) of the thrombus remover (20), the advantages of the mechanical thrombus remover (1) according to an embodiment of the present invention as described above will not be obtained. Specifically, if the open cell structure is located at the distal part (300) of the thrombus remover (20), the mechanical thrombus remover (1) can be inserted more deeply into a relatively narrow and tortuous blood vessel without damaging the blood vessel wall, but if the closed cell structure is located at the distal part (300) of the thrombus remover (20), it will be difficult to properly distribute the radial force of the distal part (300), making it difficult to insert it deep into the blood vessel, and if it is inserted into a part of the blood vessel where the radius is too narrow, the radial force of the thrombus remover (20) will rapidly increase, increasing the risk of damaging the blood vessel wall. In addition, when the open cell structure is placed in the proximal portion (200), the mechanical bonding strength of the proximal portion (200) of the thrombectomy device (20), which transmits the supporting force to advance, withdraw, or rotate the mechanical thrombectomy device (1) by being connected to the support wire (10), is low, so that sufficient supporting force cannot be transmitted, and the device cannot be used stably.

[0088] As described above, it is an important element in the mechanical thrombus removal device (1) that the open cell structure is located at the distal portion (300) of the thrombus remover (20) as in one embodiment of the present invention, and it can be seen that the longitudinal lengths of the distal portion (300) and the proximal portion (200) and the ratio of these lengths can be determined differently depending on the target blood vessel for insertion in consideration of the features described above.

[0089]

[0090] FIG. 5 is a partial view of a proximal portion (200) of an expandable frame (100) according to one embodiment of the present invention. The proximal portion (200) of the expandable frame (100) can include a ring of frame cells (230) formed of cells (210) forming the expandable frame (100). For example, the ring of frame cells (230) can include a plurality of cells (210) circumferentially interconnected to form a cylindrical expandable frame (100) structure. The cell pattern can include one or more struts or bridges, forming an expandable structure having proximal and / or distal openings for confining a thrombus. The ring of frame cells (230) can also be formed in a ring shape connected together by support struts (231) that are part of a first plurality of interconnected cells (210). One end of a support strut (231) proximal to the thrombus remover (20) is attached to a support wire (10), and the other end is connected to a connecting bridge (220) so as to mechanically support the expandable frame (100).

[0091] For this mechanical support, the support strut (231) on one side may be formed thicker than the struts of other parts forming the expandable frame (100). For example, the thickness of the support strut (231) may be formed to be about 0.025 to 0.04 mm thicker than the struts of other parts of the expandable frame (100), and preferably, about 0.028 to 0.038 mm thicker. Additionally, in the embodiment of FIG. 5, the most proximal end of the proximal portion (200), where the two support struts (231) meet, may be formed to be thicker than the support struts (231). For example, the thickness of the proximal end of the support strut (231) may be formed to be about 0.01 to 0.03 mm thicker than the support strut (231), and preferably about 0.012 to 0.025 mm thicker. As described above, by partially adjusting the strut thickness of the proximal portion (200) of the expandable frame (100) differently, the mechanical support capacity of the proximal portion (200) can be further increased.

[0092] Accordingly, higher mechanical support and bonding strength can be provided to the first plurality of cells (210) located at the proximal portion (200) of the thrombectomy device (20) compared to other portions of the thrombectomy device (20). Accordingly, when the thrombectomy device (20) is advanced or withdrawn through a narrow and tortuous blood vessel, the tensile strain of the proximal portion (200) can be smaller than the tensile strain of other portions of the thrombectomy device (20). That is, the tensile strain of the first plurality of cells (210) can be smaller than the tensile strain of the second plurality of cells (310).

[0093]

[0094] Hereinafter, the branching direction of the branch bridge (320) will be described in detail with reference to FIGS. 6 and 7. FIGS. 6 and 7 are drawings for explaining a branch bridge according to an embodiment of the present invention. In FIGS. 6 and 7, the branch bridge (320) is highlighted for convenience of explanation. In the embodiment of FIG. 6, the branch bridge (320) branches in the radial direction of the expandable frame (100), and in the embodiment of FIG. 7, the branch bridge (320) can branch in the longitudinal direction of the expandable frame (100).

[0095] As illustrated in FIG. 6, when the branch bridge (320) branches radially, the second plurality of cells (310) can have the same effect as two cells connected as one in the radial direction. When the expandable frame (100) is compressed longitudinally by the radial branch bridge (320), the force inside the expandable frame (100) can be effectively distributed due to the creation of an opening caused by the branch bridge (320), and even when the thrombus remover (20) can no longer be compressed, it can be partially overlapped instead of being folded longitudinally, thereby ensuring safety when using the mechanical thrombus remover (1).

[0096] Meanwhile, as illustrated in FIG. 7, when the branch bridge (320) branches longitudinally, the second plurality of cells (310) can have the same effect as being longitudinally connected to each other while forming a radially closed cell structure with the branch bridge (320) in between. When the expandable frame (100) is compressed radially by the longitudinal branch bridge (320), the radial force inside the expandable frame (100) can be effectively distributed due to the creation of an opening caused by the branch bridge (320), and even when the thrombus remover (20) is pressurized in a blood vessel such as a bend or branch portion of a narrow blood vessel, the distal portion (300) of the thrombus remover (20) in which the branch bridge (320) is formed can be adjusted to a smaller radial profile according to the blood vessel structure. The radial profile of the distal portion (300) will be described in detail later with reference to FIGS. 14 to 16.

[0097]

[0098] Hereinafter, various arrangements of branch bridges according to an embodiment of the present invention will be described with reference to FIGS. 8 to 12. FIG. 8 is a drawing for explaining an arrangement of a branch bridge according to an embodiment of the present invention. FIG. 9 is a drawing for explaining another arrangement of a branch bridge according to an embodiment of the present invention. FIGS. 10 to 13 are drawings for explaining still another arrangement of a branch bridge according to an embodiment of the present invention, respectively. An expandable frame (100) according to an embodiment of the present invention is briefly illustrated in a cylindrical shape in FIGS. 8 to 12 for ease of explanation.

[0099]

[0100] Referring to FIG. 8, the distal portion (300) of the expandable frame (100) may include a straight branch as briefly illustrated in the drawing. More specifically, by connecting the branch points (330) of each branch bridge formed throughout the distal portion (300) of the expandable frame (100) with a line, a branch line (340) having a shape as illustrated in the expandable frame (100) illustrated in a two-dimensional plan view may be obtained. The branch line (340) may be a first straight branch line (341) extending longitudinally along the expandable frame (100), as illustrated in the cylindrical expandable frame (100) of FIG. 8. When the distal portion (300) of the expandable frame (100) is viewed from the distal end, the circular perimeter forming the radial plane of the distal portion (300) may be seen to be interrupted by a first branch line (341). This first branch line (341) may distribute the radial force of the distal portion (300) of the expandable frame (100). The radial profile and action of the first branch line (341) will be described later with reference to FIG. 14.

[0101]

[0102] Referring to FIG. 9, in one aspect, the branch lines (341, 342) may include a plurality of straight lines having different lengths. For example, as illustrated in FIG. 9, when each of the branch points (330) formed in the distal portion (300) of the expandable frame (100) is connected with a line along the longitudinal direction of the distal portion (300), two branch lines (341, 342) may be obtained in the longitudinal direction of the expandable frame (100). These branch lines may include a first branch line (341) in the form of a straight line formed across the entire distal portion (300) of the expandable frame (100), similar to that illustrated in FIG. 8, and a second branch line (342) having a different length from the first branch line (341).

[0103] In one aspect, the first branch line (341) and the second branch line (342) can be arranged symmetrically with respect to the longitudinal axis of the expandable frame (100). By arranging the first branch line (341) and the second branch line (342) symmetrically, the thrombectomy device (20) can be seen as being divided into two semicircles when the distal portion (300) of the expandable frame (100) is viewed from the distal end. The first branch line (341) and the second branch line (342) can distribute the radial force of the distal portion of the expandable frame (100) more than in the embodiment illustrated in FIG. 8, and can also allow the radial profile to be adjusted differently. The radial profile and action of the first branch line (341) and the second branch line (342) will be described in detail later with reference to FIGS. 15 and 16.

[0104]

[0105] Referring to FIG. 10, in one aspect, the branch lines (341, 343) may further include branch lines (343) that branch laterally at least partially from the longitudinal direction of the expandable frame (100). For example, in the expandable frame (100) illustrated in a two-dimensional plan view, when each of the branch points (330) formed in the distal portion (300) of the expandable frame (100) as illustrated in FIG. 10 is connected with a line, a first branch line (341) in the form of a straight line formed over the entire distal portion (300) of the expandable frame (100) as illustrated in the cylindrical expandable frame (100) can be obtained. In addition, by connecting the branch points (330) arranged laterally with respect to the longitudinal axis of the expandable frame (100) with lines, a third branch line (343) extending to branch laterally as shown in FIG. 10 can be obtained. The first branch line (341) and the third branch line (343) distribute the radial force of the distal portion of the expandable frame (100), thereby allowing the radial profile to be adjusted.

[0106] In the embodiment illustrated in FIG. 10, the opening of the distal portion (300) formed by the third branch line (343) does not appear to split the thrombectomy device (20) into two parts when viewed from the distal end of the expandable frame (100), unlike the multiple straight branch lines illustrated in FIG. 9. However, when viewed longitudinally of the expandable frame (100) illustrated as a cylindrical shape in FIG. 10, it may appear in the form of a lateral slit along the circumferential direction of the distal portion (300) of the expandable frame (100), such as the third branch line (343) indicated by a dotted line.

[0107]

[0108] Referring to FIG. 11, in one aspect, a branch line (344) connecting branch points (330) of a branch bridge (320) may be formed in a spiral shape around the circumference of the expandable frame (100) of the distal portion (300). For example, if the branch points (330) of each branch bridge formed throughout the distal portion (300) of the expandable frame (100) are connected with a line, a diagonal branch line (344) as illustrated in the two-dimensional plan view of FIG. 11 may be obtained. In the embodiment of FIG. 11, the branch line may include a fourth branch line (344) formed in a spiral shape around the circumference of the expandable frame (100), which is illustrated as a cylinder. When the distal portion (300) of the expandable frame (100) having the fourth branch line (344) formed is viewed from the distal end, the circular perimeter forming the radial plane of the distal portion (300) may be seen to be interrupted by the fourth branch line (344). This fourth branch line (344) may distribute the radial force of the distal portion (300) of the expandable frame (100). The radial profile and action of the fourth branch line (344) will be described later with reference to FIG. 14.

[0109]

[0110] Referring to FIG. 12, in one aspect, branch lines (345) connecting branch points (330) of branch bridges (320) may be longitudinally wavy along the expandable frame (100) of the distal portion (300). For example, by connecting the branch points (330) of each branch bridge formed throughout the distal portion (300) of the expandable frame (100) with a line, a branch line (345) having a wavy shape as illustrated in the two-dimensional plan view of FIG. 12 may be obtained. In the embodiment of FIG. 12, the branch line (345) may include a fifth branch line (345) having a wavy shape substantially identical to the cell pattern of the distal portion (300) of the expandable frame (100) with respect to the longitudinal axis of the expandable frame (100) illustrated as a cylinder. When the distal portion (300) of the expandable frame (100) having the fifth branch line (345) formed is viewed from the distal end, the circular perimeter forming the radial plane of the distal portion (300) may be seen to be interrupted by the fifth branch line (345). This fifth branch line (345) can distribute the radial force of the distal portion (300) of the expandable frame (100). The radial profile and action of the fifth branch line (345) will be described later with reference to FIG. 14.

[0111]

[0112] Referring to FIG. 13, in one aspect, the branch bridges (320) can be at least partially spaced apart from each other longitudinally or radially with cells (310) interposed therebetween that are connected to each other along the expandable frame (100) of the distal portion (300). For example, as illustrated in FIG. 13, each branch bridge (320) does not have branch points (330) that are connected to each other to form a separate branch line. The branch bridges (320) can be spaced apart from each other longitudinally of the distal portion (300) of the expandable frame (100). Alternatively, the branch bridges (320) can be spaced apart from each other radially of the distal portion (300) of the expandable frame (100). Although not illustrated in the drawing, one of the spaced apart branch bridges (320) can be arranged continuously with another branch bridge (320) to form a branch line. The arrangement of the branch bridge (320) described above can form an opening in the distal (300) side of the expandable frame (100) to disperse the radial or axial force of the expandable frame (100), and the opening can also act as an entrance through which a thrombus can enter and be captured within the expandable frame (100) within the blood vessel.

[0113] The shape of the branch bridge (320) and each branch line (341, 342, 343, 344, 345) described with respect to FIGS. 8 to 13 can be appropriately selected in consideration of various characteristic conditions such as the condition of the surgical target and the location, size, and shape of the blood vessel into which the mechanical thrombus removal device (1) is inserted.

[0114]

[0115] Hereinafter, with reference to FIGS. 14 to 16, the branch portion of the branch bridge (320) and the radial profile and operation of the distal portion (300) of the expandable frame (100) will be described. In FIGS. 14 to 16, for clarity, the radial profile is illustrated by simplifying and emphasizing the cross-sectional area of ​​the expandable frame (100), and the radial plane of the distal portion (300) is illustrated by enlarging it with a dotted line centered on the maximum circumference of the expandable frame (100).

[0116]

[0117] First, with regard to the radial profile of the expandable frame (100), the radial profile refers to the shape of a cross-section cut perpendicular to the longitudinal axis of the expandable frame (100). Generally, the expandable frame (100) has an overall cylindrical shape, and thus may have a circular profile of a constant size throughout the length of the expandable frame (100). However, the thrombus remover (20) of the present invention does not have a constant radial profile overall, since the shapes of the proximal portion (200) and the distal portion (300) are different. That is, the proximal portion (200) of the thrombus remover (20) of the present invention may have a circular profile, but the distal portion (300) may have different radial profiles depending on the shape of the branch bridge (320). For example, if there is only one branch line of the branch bridge (320), the radial profile of the distal portion (300) may have a tapered profile in which one end of the cross-section of the distal portion (300) becomes narrower or wider. Alternatively, if there are multiple branch lines of the branch bridge (320), the cross-section of the distal portion (300) may have a stepped profile in which the cross-section is composed of multiple sections.

[0118]

[0119] Referring to FIG. 14, a distal portion (300) of an expandable frame (100) including a straight branch line (340) as described above with respect to FIG. 8 is partially illustrated. For example, in the case of having a single straight branch line, the branch portion (350) of the branch bridge (320) may have branch points that contact each other as illustrated in FIG. 14. In the case of having a plurality of straight branch lines, the branch portion (350) of the branch bridge (320) may have struts of each cell forming the branch bridge that at least partially overlap each other as illustrated in FIG. 15, or the branch points of the branch bridge (320) may be spaced apart from each other and not in contact as illustrated in FIG. 16. In one aspect, even when the distal portion (300) has a single slit-shaped branch line that is not a straight line longitudinally to the distal end of the expandable frame (100) as described above with respect to FIGS. 11 and 12, the branch portions (350) of the branch bridges (320) may be in contact with each other as shown in FIG. 14, or may be spaced apart from each other or at least partially overlap each other as shown in FIGS. 15 and 16 without contacting each other.

[0120] The distal portion (300) including the branch portion (350) may be deformable such that the radial plane of the distal portion (300) becomes wider than the radial plane of the proximal portion (200) when placed in a free space where an external pressure applied to the expandable frame (100) from one side is smaller than a radial force inside the expandable frame (100), and such that the radial plane of the distal portion (300) becomes narrower than the radial plane of the proximal portion (200) when introduced into a blood vessel. For example, when the branch portions (350) of the distal portion (300) are placed in contact with each other in the initial shape of the cylindrical expandable frame (100) without overlapping or spacing each other, the radial planes of the proximal portion (200) and the distal portion (300) are the same size. However, when the thrombolytic device (20) is placed in a blood vessel and pressurized, the distal portion (300) having the branch portion (350) can effectively distribute the radial force compared to the proximal portion (200), so that the radial plane (360) of the distal portion (300) can be smaller than the radial plane (240) of the proximal portion (200), and in a free space where the external pressure applied to the expandable frame (100) is smaller than the radial force inside the expandable frame (100), the radial plane (360) of the distal portion (300) can be larger than the radial plane (240) of the proximal portion (200).

[0121] The variation of the radial profile and radial plane (360) of the distal portion (300) is illustrated, for example, in the lower portion of FIG. 14. When the radial plane (360) of the distal portion (300) becomes smaller, the distal portion (300) can have a tapered profile in which the separated end of the expandable frame (100) rolls inward of the radial plane (360). When the radial plane (360) of the distal portion (300) becomes larger than the radial plane (240) of the proximal portion (200), the distal portion (300) can have a profile in which the separated end of the expandable frame (100) rolls outward of the radial plane (240) of the proximal portion (200).

[0122] Alternatively, since the shape memory alloy tube has the flexibility to be deformed into various shapes and the ability to recover the shape memory, the distal portion (300) and the proximal portion (200) of the shape memory alloy tube used in manufacturing the thrombectomy device (20) can be shape-memory-formed to have different cross-sectional areas, thereby enabling such a change in the radial plane (360) of the distal portion (300). In addition, the distal portion (300) may be subjected to secondary heat treatment and cooling to form a shape memory so that the radial plane (360) becomes wider than the proximal portion (200) in a free space where the external pressure applied to the expandable frame (100) is smaller than the radial force inside the expandable frame (100), and the radial plane (360) becomes narrower than the proximal portion (200) in a narrow blood vessel where the external pressure applied to the expandable frame (100) is larger than the radial force inside the expandable frame (100), thereby enabling insertion into a deep blood vessel during surgery while more reliably capturing a thrombus in a relatively wide blood vessel.

[0123]

[0124] Referring to FIG. 15, a distal portion (300) of an expandable frame (100) including two straight branch lines is partially illustrated. For example, when having two branch lines, the branch lines (350) can at least partially overlap each other as illustrated in FIG. 15 on one side. The radial profile of the distal portion (300) having the overlapping branch lines (350) is as illustrated and simplified for illustration in the lower portion of FIG. 15. The distal portion (300) of the expandable frame (100) can have a radial profile formed of two semicircular shapes. A radial profile as illustrated in FIG. 15 can be seen when the distal portion (300) of the expandable frame (100) is pressurized by a radial force. In this case, the radial plane (360) of the distal portion (300) of the expandable frame (100) may be smaller than the radial plane (240) of the proximal portion (200). This radial profile allows the radial force of the distal portion (300) of the thrombolytic device (20) to be effectively distributed, allowing the distal portion (300) to be transmitted to relatively narrower and deeper blood vessels.

[0125]

[0126] Referring to FIG. 16, a distal portion (300) of an expandable frame (100) including two straight branch lines is partially illustrated. In the embodiment of FIG. 16, the branch lines (350) may be spaced apart without contacting each other. The radial profile of this distal portion (300) is as illustrated in the lower portion of FIG. 16. The distal portion (300) of the expandable frame (100) may have a radial profile composed of two semicircular shapes, and these semicircular profiles may be spaced apart without overlapping each other. A radial profile as illustrated in FIG. 16 may be observed when the thrombectomy device (20) is arranged in the free space described above. This radial profile effectively distributes the radial force of the distal portion (300) of the thrombectomy device (20), making it difficult to place a thrombectomy device with a closed cell structure and effectively removing thrombi even in relatively wide intravascular locations.

[0127]

[0128] Although the present invention has been described with reference to the drawings and embodiments, it does not mean that the scope of protection of the present invention is limited by the drawings or embodiments, and it will be understood that a person skilled in the art can modify and change the present invention in various ways without departing from the spirit and scope of the present invention as described in the following claims.

[0129] Although the present invention described above is described based on a series of functional blocks, it is not limited to the above-described embodiments and the attached drawings, and it will be apparent to those skilled in the art to which the present invention pertains that various substitutions, modifications, and changes are possible within a scope that does not depart from the technical spirit of the present invention.

[0130] The combination of the above-described embodiments is not limited to the above-described embodiments, and various combinations may be provided in addition to the above-described embodiments depending on implementation and / or needs.

[0131] In the above-described embodiments, the methods are described based on a flowchart as a series of steps or blocks. However, the present invention is not limited to the order of the steps, and some steps may occur in a different order or simultaneously with other steps described above. Furthermore, those skilled in the art will understand that the steps depicted in the flowchart are not exclusive, and other steps may be included, or one or more steps in the flowchart may be deleted without affecting the scope of the present invention.

[0132] The above-described embodiments include examples of various aspects. While not all possible combinations to illustrate the various aspects can be described, those skilled in the art will recognize that other combinations are possible. Accordingly, the present invention is intended to encompass all other alterations, modifications, and variations within the scope of the following claims.

[0133] [Explanation of symbols]

[0134] 1: Mechanical thrombectomy device

[0135] 10: Support wire

[0136] 20: Thrombolytic Device

[0137] 100: Expandable frame

[0138] 200: Guards

[0139] 210: The first multiple cells

[0140] 220: Connecting Bridge

[0141] 230: Ring of frame cell

[0142] 231: Support strut

[0143] 240: Radial plane of the proximal part

[0144] 300: Distal

[0145] 310: Second Revenge Cells

[0146] 320: Branch Bridge

[0147] 330: Branching point

[0148] 340: Branch line

[0149] 341: First branch line

[0150] 342: Second branch line

[0151] 343: Third branch line

[0152] 344: 4th branch line

[0153] 345: Fifth branch line

[0154] 350: Branch

[0155] 360: Radial plane of the distal part

Claims

1. As a mechanical thrombectomy device, support wire; and A clot arrestor connected to the support wire and having an expandable frame; The above expandable frame is, a proximal portion in which the first plurality of cells of the above expandable frame are connected to each other; and A second plurality of cells of the expandable frame, comprising a distal portion at least partially separated from each other; Mechanical thrombectomy device.

2. In paragraph 1, The above first plurality of cells are connected by a connecting bridge that interconnects each cell, The second plurality of cells are each separated from the distal portion, forming a branch bridge. Mechanical thrombectomy device.

3. In paragraph 2, The expandable frame of the above proximal portion comprises a ring of frame cells, The ring of the above frame cell is, A support strut formed by a portion of a plurality of first cells connected to each other, one end of the support strut being attached to the support wire and the other end being connected to the connecting bridge, thereby mechanically supporting the expandable frame. Mechanical thrombectomy device.

4. In paragraph 3, When the thrombolytic device is moved through the curved blood vessel, the tensile strain of the first plurality of cells is smaller than the tensile strain of the second plurality of cells. Mechanical thrombectomy device.

5. In paragraph 2, The above distal part is, Adjustable radial profile, Mechanical thrombectomy device.

6. In paragraph 5, The distal portion is deformable so that when placed in free space, the radial plane of the distal portion becomes wider than the radial plane of the proximal portion, and when introduced into a blood vessel, the radial plane of the distal portion becomes narrower than the radial plane of the proximal portion. Mechanical thrombectomy device.

7. In paragraph 5, The above branch bridge branches longitudinally of the above expandable frame, Mechanical thrombectomy device.

8. In paragraph 5, The above branch bridge branches radially from the expandable frame, Mechanical thrombectomy device.

9. In paragraph 5, The branch line connecting the branch points of the above branch bridge is a straight line longitudinally along the expandable frame. Mechanical thrombectomy device.

10. In paragraph 9, The above branch line includes multiple straight lines of different lengths, Mechanical thrombectomy device.

11. In paragraph 10, At least two of the above plurality of straight lines are arranged symmetrically with respect to the longitudinal axis, Mechanical thrombectomy device.

12. In paragraph 9, Further comprising a branch line branching laterally at least partially from the longitudinal direction of the above expandable frame, Mechanical thrombectomy device.

13. In paragraph 5, The branch sections of the above branch bridges overlap each other at least partially, Mechanical thrombectomy device.

14. In paragraph 5, The above branch bridges are spaced apart from each other at least partially in the longitudinal or radial direction with cells interposed therebetween along the expandable frame of the distal portion. Mechanical thrombectomy device.

15. In paragraph 5, The branch line connecting the branch points of the above branch bridge is spiral along the circumference of the expandable frame of the above distal part. Mechanical thrombectomy device.

16. In paragraph 5, The branch line connecting the branch points of the above branch bridge is longitudinally wavy along the expandable frame of the above distal part. Mechanical thrombectomy device.

17. In paragraph 2, The above branch bridge is ground or tapered to form a smooth edge, Mechanical thrombectomy device.

18. In paragraph 1, The longitudinal length of the proximal portion and the longitudinal length of the distal portion are different from each other. Mechanical thrombectomy device.

19. In paragraph 18, The ratio of the longitudinal lengths of the proximal and distal portions is Depending on the target blood vessel for insertion of the mechanical thrombectomy device, Mechanical thrombectomy device.

20. In paragraph 1, The above expandable frame is formed by laser cutting a shape memory alloy tube. Mechanical thrombectomy device.

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