KR102716297B1 - Mechanical thrombectomy device - Google Patents

Abstract

A mechanical thrombectomy device is provided. The mechanical thrombectomy device may include a support wire; and a thrombectomy device connected to the support wire and having an expandable frame. The expandable frame may include a proximal portion, wherein a first plurality of cells of the expandable frame are connected to one another; and a distal portion, wherein a second plurality of cells of the expandable frame are at least partially separated from one another.

Description

MECHANICAL THROMBECTOMY DEVICE

The present invention relates to a thrombus removal device, and more particularly, but not exclusively, to a mechanical thrombus removal device used for removing a thrombus in a blood vessel.

There are a variety of methods for treating blood clots that have formed in specific blood vessel sites in the body. Among them, mechanical clot removal devices are inserted into the blood vessel to break up or remove the clot within the blood vessel, thereby restoring perfusion through the occluded blood vessel. Mechanical clot removal devices approved for this purpose include clot filters, clot aspiration devices, coil retrievers, and more recently, stent retriever devices.

Stent retriever devices are mainly used to remove acute thrombus in stroke patients. A self-expanding stent made of a type of wire mesh is placed in a blood vessel to capture the thrombus, and the stent is retrieved from the patient together with the thrombus by pulling the support wire of the stent retriever. In terms of usability and performance, such stent retriever devices must have visibility under fluoroscopy and the ability to capture, confine, or maintain a thrombus without damaging the blood vessel in a narrow and tortuous blood vessel structure. In addition, they must not cause any hazardous situations during surgery.

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.

In addition, conventional stent retriever devices with a cylindrical structure in which all cells of the stent are open have safety issues because the thrombus removal device may be unnecessarily stretched and lose the captured thrombus when the stent retriever device is moved through a narrow and tortuous blood vessel, or the device may become fatigued due to repeated excessive tensile deformation.

Korean Patent Publication No. 10-0960974 (“Temporary Blood Flow Improvement Device”, Asan Social Welfare Foundation)

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 tensioning.

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

Another object of the present invention to solve the above-mentioned problems is to provide a mechanical thrombus removal device having an extendable frame of the thrombus remover having a proximal portion 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.

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.

According to one embodiment of the present invention for achieving the above-described purpose, a thrombectomy device is a mechanical thrombectomy device, comprising: a clot arrestor having a support wire; and an expandable frame connected to the support wire; 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.

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.

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.

According to one aspect, when the thrombus remover is moved through the 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.

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

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, the radial plane of the distal portion becomes narrower than a radial plane of the proximal portion.

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

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

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.

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

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.

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

According to one aspect, the branch sections of the branch bridge can at least partially overlap each other.

In 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.

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.

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.

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

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.

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.

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

The disclosed technology may have the following effects. However, this does not mean that a specific 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.

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.

In addition, the mechanical thrombus removal device according to one 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 deeply enter even complex and narrow blood vessels and prevent excessive tensile deformation, thereby providing a stable and excellent thrombus removal device.

FIG. 1 is a plan view of a mechanical thrombus removal device according to one embodiment of the present invention.
FIG. 2 is a plan view of a thrombus remover according to one embodiment of the present invention.
FIG. 3 is an enlarged view of a connecting bridge according to one embodiment of the present invention.
FIG. 4 is an enlarged view of a branch bridge according to one embodiment of the present invention.
FIG. 5 is a drawing partially illustrating a proximal portion of a thrombus remover according to one embodiment of the present invention.
FIG. 6 is a drawing for explaining a branch bridge according to one embodiment of the present invention.
FIG. 7 is a drawing for explaining a branch bridge according to one embodiment of the present invention.
FIG. 8 is a drawing for explaining the arrangement of a branch bridge according to one embodiment of the present invention.
FIG. 9 is a drawing for explaining another arrangement of a branch bridge according to one embodiment of the present invention.
FIG. 10 is a drawing for explaining another arrangement of a branch bridge according to one embodiment of the present invention.
FIG. 11 is a drawing for explaining another arrangement of a branch bridge according to one embodiment of the present invention.
FIG. 12 is a drawing for explaining another arrangement of a branch bridge according to one embodiment of the present invention.
FIG. 13 is a drawing for explaining another arrangement of a branch bridge according to one embodiment of the present invention.
FIG. 14 is a drawing illustrating a branch bridge shape and a radial profile of a distal portion thereof according to one embodiment of the present invention.
FIG. 15 is a drawing illustrating another form of a branch bridge and a radial profile of a distal portion thereof according to one embodiment of the present invention.
FIG. 16 is a drawing illustrating another form of a branch bridge and a radial profile of a distal portion thereof according to one embodiment of the present invention.

The present invention can have various modifications and embodiments, and specific embodiments are illustrated in the drawings and described in detail.

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

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are only used to distinguish one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component. The term and/or includes any combination of a plurality of related described items or any item among a plurality of related described items.

When it is said that a component is "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 in between. On the other hand, when it is said that a component is "directly connected" or "directly connected" to another component, it should be understood that there are no other components in between.

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 "comprises" or "has" and the like are intended to specify 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.

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 belongs. Terms defined in commonly used dictionaries, such as those defined in common dictionaries, should be interpreted as having a meaning consistent with the meaning they have in the context of the relevant art, and will not be interpreted in an idealized or overly formal sense unless expressly defined in this application.

Hereinafter, with reference to the attached drawings, a preferred embodiment of the present invention will be described in more detail. In order to facilitate an overall understanding in describing the present invention, the same reference numerals are used for the same components in the drawings, and redundant descriptions of the same components are omitted.

As discussed above, since the conventional stent retriever device has a structure in which all cells of the stent are directly connected or entirely separated, the radial force of the expandable frame of the thrombus remover cannot be partially varied, and accordingly, there was a problem that damage to the vascular tissue could occur if the radial force increased rapidly, 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.

A mechanical thrombus removal device according to one embodiment of the present disclosure is intended to solve the above-described problems, and provides a mechanical thrombus removal device in which a proximal portion of the thrombus remover is formed of cells that are interconnected to provide structural support for repetitive tensile deformation, thereby improving the durability of the mechanical thrombus remover, and a distal portion of the thrombus remover is formed of partially separated cells, thereby preventing rapid changes in radial force, thereby preventing damage to delicate vascular tissue.

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.

Hereinafter, the term 'thrombotic device' in this description may refer to, for example, a portion of a general stent retriever including 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.

Additionally, the term 'expandable frame' in the present 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.

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 clot remover. Likewise, '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 clot remover to any particular configuration described in the various embodiments below.

FIG. 1 is a plan view of a mechanical thrombus removal device (1) according to one embodiment of the present invention. As shown 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).

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 can be pushed by an operator to advance the distal working region, pulled by an operator to withdraw the distal working region, or rotated by an operator 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.

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

The clot remover (20) can be sized and shaped to provide a degree 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 contractile 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.

Although not shown in the drawing, the expandable frame (100) may be equipped with a plurality of radiopaque markers. The radiopaque markers may enhance the visibility of the device and provide a cue for the operator to locate a clot relative to the clot remover. The radiopaque markers may include radiopaque markers equipped in a variety of ways, including radiopaque bands, wire coils, plating, or 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.

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.

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 thrombus remover (20).

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) of the expandable frame (100) are connected to each other. Additionally, 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) at which the second plurality of cells (310) of the longitudinally expandable frame (100) are at least partially separated from each other.

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, the branch bridge (320) is configured such that the struts forming the 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 from each other 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 methods at all portions that may contact a vessel surface 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.

Although the proximal portion (200) and the distal portion (300) described above are depicted 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 thrombus removal device (1).

For example, when a mechanical thrombus removal 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 size of the radial force of the distal portion (300) to be small, thereby reducing damage to the blood vessel tissue and delivering the mechanical thrombus removal device (1) to a deeper location in the blood vessel. In addition, when a mechanical thrombus removal 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 supporting force of the mechanical thrombus removal device (1), thereby enabling more reliable capture and recovery of a thrombus within the blood vessel.

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.

The advantages of the closed-cell structure are as follows: 1. It can support and maintain stability of the blood vessel inner wall by providing strong mechanical support due to the structural connection between the closed cells. 2. Since the closed-cell structure is structurally connected, it is easy to accurately place in the blood vessel, and it is effective in capturing and retrieving blood clots because it has little tensile deformation when moving in the blood vessel.

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 connection, which may limit the ability of the thrombectomy device to move naturally with the movement of the blood vessel. 2. The closed-cell structure may have difficulty in dissipating radial forces due to the structural connection between each cell, which may cause a sharp increase in radial force at a certain point and cause damage to the blood vessel wall. 3. The closed-cell structure may have limited adaptability to the structure of the blood vessel, such as in the case of special vascular anatomy characteristics such as bends or branching areas of the blood vessel.

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. A frame of an open cell structure may have conflicting aspects with a frame of a closed cell structure.

The advantages of open cell structure are as follows: 1. The open cell structure can improve the flexibility and flexibility of the thrombectomy device, and help 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.

Disadvantages of open cell structures include: 1. Open cell structures may not be able to effectively remove clots once they are located in the openings or slits, which may impair blood flow. 2. Open cell structures may have structural limitations in the size and shape of the openings or slits, which may make them difficult to apply to certain vascular anatomy. 3. Open cell structures may be subject to excessive tensile deformation due to the presence of the openings or slits, which may result in loss of captured clots or difficulty in capturing and removing the clots.

In an actual surgical operation, when an operator uses only the closed-cell structure thrombus removal device or only the open-cell structure thrombus removal device alone, 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, 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 according to an embodiment of the present invention.

A mechanical thrombus remover (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 thrombus remover (20), the flexibility and adaptability of the thrombus remover (20) can be improved, and the distal portion (300) of the thrombus remover (20) can bend according to pressure and move according to the natural movement of the blood vessel, so that it can be inserted more deeply into a relatively narrow and tortuous blood vessel compared to a thrombus remover having only a closed-cell structure. 2. The distal portion (300) of the open-cell structure can distribute the pressure between the thrombus remover (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.

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 the embodiment of the present invention 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 thrombus remover (20), which is connected to the support wire (10) and transmits a supporting force to advance, withdraw, or rotate the mechanical thrombus remover (1), is low, so that sufficient supporting force cannot be transmitted, and thus the device cannot be used stably.

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.

FIG. 5 is a partial diagram illustrating 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 and can form an expandable structure having proximal and/or distal openings to confine a clot. The ring of frame cells (230) can also be formed in a ring shape that is connected as one by support struts (231) that are part of a first plurality of cells (210) that are connected to each other. One end of a support strut (231) proximal to the thrombus remover (20) is attached to the support wire (10), and the other end is connected to a connecting bridge (220) so as to mechanically support the expandable frame (100).

For this mechanical support, the support strut (231) on one side can be formed thicker than the struts of other parts forming the expandable frame (100). For example, the thickness of the support strut (231) can 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, can be formed to be 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 can 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 that of 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.

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 thrombus remover (20) compared to other portions of the thrombus remover (20). Accordingly, when the thrombus remover (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 thrombus remover (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).

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 one embodiment of the present invention. In FIGS. 6 and 7, the branch bridge (320) is emphasized 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).

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).

Meanwhile, as illustrated in FIG. 7, when the branch bridge (320) branches longitudinally, the second plurality of cells (310) may have an effect as if they are longitudinally connected to each other while forming a closed cell structure in the radial direction with the branch bridge (320) therebetween. When the expandable frame (100) is compressed radially by the longitudinal branch bridge (320), the radial force inside the expandable frame (100) may 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) where the branch bridge (320) is formed may 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.

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.

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, when 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 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 as being interrupted by the first branch line (341). The 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.

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 by 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).

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.

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) disperse the radial force of the distal portion of the expandable frame (100), thereby allowing the radial profile to be adjusted.

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 divide the thrombus remover (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 cylinder in FIG. 10, it may be viewed 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.

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 along the circumference of an expandable frame (100) of a 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 along the circumference of the expandable frame (100), which is illustrated as a cylinder. When the distal portion (300) of the expandable frame (100) on which the fourth branch line (344) is formed is viewed from the distal end, the circular perimeter forming the radial plane of the distal portion (300) may be seen as being interrupted by the fourth branch line (344). This fourth branch line (344) may disperse 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.

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, if branch points (330) of each branch bridge formed throughout the distal portion (300) of the expandable frame (100) are connected 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) on which the fifth branch line (345) is formed is viewed from the distal end, the circular perimeter forming the radial plane of the distal portion (300) may be seen as being interrupted by the fifth branch line (345). This fifth branch line (345) may disperse 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.

Referring to FIG. 13 , in one aspect, the branch bridges (320) can be at least partially spaced apart from each other in the longitudinal or radial direction 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 of the branch bridges (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 in the longitudinal direction of the distal portion (300) of the expandable frame (100). Additionally, the branch bridges (320) can be spaced apart from each other in the radial direction 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.

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.

Hereinafter, with reference to FIGS. 14 to 16, the branch portion of the branch bridge (320) and the radial plane (360) and radial profile and their actions 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).

First, with regard to the radial profile of the expandable frame (100), the radial profile means the shape of a cross-section cut perpendicularly to the longitudinal axis of the expandable frame (100). In general, 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, when the branch line of the branch bridge (320) is one, 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, when the branch line of the branch bridge (320) is multiple, the cross section of the distal portion (300) may have a stepped profile in which the cross section is composed of multiple sections.

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 a form in which the branch points 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 a form in which the struts of each cell forming the branch bridge at least partially overlap each other as illustrated in FIG. 15, or the branch points of the branch bridge (320) may be arranged spaced apart from each other without contacting each other 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 illustrated in FIG. 14, or may be spaced apart from or at least partially overlapping each other as illustrated in FIGS. 15 and 16 without contacting each other.

The distal portion (300) including the branch portion (350) may be deformable such that when the radial plane of the distal portion (300) is 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), the radial plane of the distal portion (300) becomes wider than the radial plane of the proximal portion (200), and when introduced into a blood vessel, the radial plane of the distal portion (300) becomes narrower than the radial plane of the proximal portion (200). For example, when the branch portions (350) of the distal portion (300) are placed in contact with each other as 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 thrombus remover (20) is placed in a blood vessel and pressurized, the distal portion (300) having the branch portion (350) can effectively disperse the radial force compared to the proximal portion (200), so that the radial plane (360) of the distal portion (300) can become 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 become larger than the radial plane (240) of the proximal portion (200).

Such variations in the radial profile and radial plane (360) of the distal portion (300) are 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 such that 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 such that the separated end of the expandable frame (100) rolls outward of the radial plane (240) of the proximal portion (200).

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 thrombus remover (20) can be shape-memoriated to have different cross-sectional areas, thereby making such a change in the radial plane (360) of the distal portion (300) possible. 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 deep blood vessels during surgery while more reliably capturing thrombi in relatively wide blood vessels.

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. The radial profile of the distal portion (300) having the overlapping branch lines (350) is as illustrated and simplified for illustration at the bottom of FIG. 15. The distal portion (300) of the expandable frame (100) can have a radial profile formed of two semicircular shapes. The 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 thrombus remover (20) to be effectively distributed, allowing the distal portion (300) to be transmitted to relatively narrower and deeper blood vessels.

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 the 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 comprised of two semicircular shapes, wherein the semicircular profiles may be spaced apart without overlapping each other. The radial profile as illustrated in FIG. 16 may be seen 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), thereby effectively removing thrombi even in locations where it is difficult to place a thrombectomy device with a closed cell structure and in relatively wide intravascular locations.

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 variously modify and change the present invention without departing from the spirit and scope of the present invention as described in the claims below.

Although the present invention described above has been 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 that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention.

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.

In the above-described embodiments, the methods are described based on the flowchart as a series of steps or blocks, but 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. In addition, those skilled in the art will understand that the steps shown 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.

The above-described embodiments include examples of various aspects. Although it is not possible to describe all possible combinations to represent various aspects, those skilled in the art will recognize that other combinations are possible. Accordingly, it is intended that the present invention include all other alterations, modifications, and changes that fall within the scope of the following claims.

1: Mechanical thrombus removal device
10: Support wire
20: Thrombolytic Device
100 : Expandable Frame
200 : Guards
210: The first multiple cells
220 : Connection Bridge
230: Ring of frame cell
231 : Support Strut
240: Radial plane of the proximal part
300 : Distal
310: Second Revenge Cells
320 : Branch Bridge
330 : Branching point
340 : Branch line
341: First branch line
342: Second branch line
343: Third Quarter Line
344: 4th branch line
345: Fifth branch line
350 : Branch
360: Radial plane of the distal part

Claims (20)

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 distal portion of the second plurality of cells of the expandable frame at least partially separated from one another;
The above first plurality of cells are connected by a connecting bridge that interconnects each cell,
The above second plurality of cells are separated from each other in the distal portion and form a branch bridge,
The above distal portion has an adjustable radial profile,
The branch line connecting the branch points of the above branch bridge is a straight line in the direction of the central axis from the proximal to the distal portion along the expandable frame.
Mechanical thrombectomy device.
delete In paragraph 1,
The expandable frame of the above proximal portion comprises a ring of frame cells,
The ring of the above frame cell is,
A ring-shaped structure formed by connecting a plurality of first cells connected to each other by a support strut, one end of which is attached to the support wire and the other end is connected to the connecting bridge, thereby mechanically supporting the expandable frame.
Mechanical thrombectomy device.
In the third paragraph,
When the above thrombus remover 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 due to the mechanical support force resulting from the connection between the first plurality of cells.
Mechanical thrombectomy device.
delete In paragraph 1,
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.
In paragraph 1,
The above branch bridge branches in the direction of the central axis from the proximal to the distal portion of the above expandable frame.
Mechanical thrombectomy device.
In paragraph 1,
The above branch bridge branches radially from the expandable frame,
Mechanical thrombectomy device.
delete In paragraph 1,
The above branch line includes multiple straight lines of different lengths.
Mechanical thrombectomy device.
In Article 10,
At least two of the above multiple straight lines are arranged in a direction symmetrical to each other with respect to the central axis.
Mechanical thrombectomy device.
In paragraph 1,
Further comprising a branch line branching at least partially laterally from a central axis direction from the proximal to the distal portion of the expandable frame;
Mechanical thrombectomy device.
In paragraph 1,
The branch sections of the above branch bridges at least partially overlap each other,
Mechanical thrombectomy device.
In paragraph 1,
The above branch bridge has a central axis extending from the proximal to the distal portion of the expandable frame, with cells interposed between them along the expandable frame of the distal portion. at least partially spaced apart from each other in a direction or radial direction,
Mechanical thrombectomy device.
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 distal portion of the second plurality of cells of the expandable frame at least partially separated from one another;
The above first plurality of cells are connected by a connecting bridge that interconnects each cell,
The above second plurality of cells are separated from each other in the distal portion and form a branch bridge,
The above distal portion has an adjustable radial profile,
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.
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 distal portion of the second plurality of cells of the expandable frame at least partially separated from one another;
The above first plurality of cells are connected by a connecting bridge that interconnects each cell,
The above second plurality of cells are separated from each other in the distal portion and form a branch bridge,
The above distal portion has an adjustable radial profile,
The branch line connecting the branch points of the above branch bridge is wavy in the direction of the central axis from the proximal part to the distal part of the expandable frame of the above distal part.
Mechanical thrombectomy device.
In paragraph 1,
The above branch bridges are ground or tapered to form smooth edges.
Mechanical thrombectomy device.
In paragraph 1,
The central axis length of the above proximal portion and the central axis length of the above distal portion are different from each other.
Mechanical thrombectomy device.
In Article 18,
The ratio of the length of the central axis of the above proximal and distal parts is
Depending on the target blood vessel for insertion of the mechanical thrombectomy device, it is determined differently.
Mechanical thrombectomy device.
In paragraph 1,
The above expandable frame is formed by laser cutting a shape memory alloy tube.
Mechanical thrombectomy device.

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