Thrombectomy stent

Abstract

The utility model discloses a thrombectomy stent which comprises an outer stent body, an inner stent body and an outer stent body. The inner-layer stent is provided with a second contraction configuration for radial contraction and a second expansion configuration for radial expansion; the inner-layer bracket is arranged in the outer-layer bracket; when the outer-layer stent is in the first expansion configuration and the inner-layer stent is in the second expansion configuration, a distance is formed between the inner-layer stent and the outer-layer stent in the radial direction, and a clamping position for fixing thrombus is formed between the outer side wall of the inner-layer stent and the inner side wall of the outer-layer stent. By controlling the releasing sequence of the outer-layer stent and the inner-layer stent, part of thrombus can be pressed towards the position of the outer-layer stent when the inner-layer stent is released, the thrombus is caught in an embedded mode through a clamping position formed between the inner-layer stent and the outer-layer stent, and then the thrombus is not prone to escaping in the thrombus taking process.

Description

Technical Field

[0001] The utility model relates to the technical field of medical devices, in particular to a thrombus removal bracket. Background Art

[0002] Stroke is a disease caused by sudden rupture of blood vessels in the brain or blockage of blood vessels that prevents blood from flowing into the brain, resulting in brain tissue damage. It includes ischemic stroke and hemorrhagic stroke. Stroke is one of the main diseases that cause death and disability in humans.

[0003] Endovascular thrombectomy is the first choice for patients with acute ischemic stroke caused by large vessel occlusion. The current thrombectomy stent can remove the thrombus in the artery, but because the thrombectomy of the thrombectomy stent is completely dependent on the stent embedding of the thrombus, a large number of thrombi are not firmly embedded. During the thrombectomy process, the thrombus escapes, and the thrombectomy stent needs to be used repeatedly. Utility Model Content

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the current thrombus removal stent is not firmly embedded in the thrombus, thereby providing a thrombus removal stent.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0006] A thrombectomy stent, comprising:

[0007] The outer stent has a radially contracted first contracted configuration and a radially expanded first expanded configuration;

[0008] The inner stent has a radially contracted second contracted configuration and a radially expanded second expanded configuration;

[0009] The inner layer support is arranged inside the outer layer support;

[0010] When the outer stent is in the first expansion configuration and the inner stent is in the second expansion configuration, the inner stent and the outer stent have a distance in the radial direction, and a clamping position for fixing the thrombus is formed between the outer wall of the inner stent and the inner wall of the outer stent.

[0011] To further optimize the technical solution, the outer layer stent has a plurality of first mesh units that allow thrombus to enter, and the inner layer stent has a plurality of second mesh units that allow thrombus to enter, and the size of the second mesh units is larger than the size of the first mesh units.

[0012] To further optimize the technical solution, the inner support can move relative to the outer support.

[0013] To further optimize the technical solution, a first pushing wire is disposed at the proximal end of the outer layer stent, and a second pushing wire is disposed at the proximal end of the inner layer stent.

[0014] To further optimize the technical solution, a first thrombus positioning portion is provided on the outer layer stent extending inwardly; and / or a second thrombus positioning portion is provided on the inner layer stent extending outwardly.

[0015] To further optimize the technical solution, the first thrombus positioning portion and / or the second thrombus positioning portion may be elastically deformed in a radial direction.

[0016] To further optimize the technical solution, a first thrombus locating portion is provided on the outer layer stent extending inwardly, and the first thrombus locating portion includes at least one first barb, and the first barb points to the proximal end of the outer layer stent.

[0017] To further optimize the technical solution, a second thrombus positioning portion is provided on the inner layer stent extending outwardly, and the second thrombus positioning portion includes at least one second barb, and the second barb points to the proximal end of the inner layer stent.

[0018] To further optimize the technical solution, the outer layer stent is provided with a first barb extending inwardly, and the inner layer stent is provided with a second barb extending outwardly, and after the outer layer stent and the inner layer stent are radially expanded, the first barb and the second barb are arranged in a staggered manner.

[0019] To further optimize the technical solution, the clamping position is an annular clamping position.

[0020] The technical solution of the utility model has the following advantages:

[0021] 1. The utility model provides a thrombus removal stent, in which the clamping position formed between the inner stent and the outer stent realizes the embedded capture of the thrombus. The thrombus is clamped by the inner stent and the outer stent, and the bonding strength with the thrombus removal stent is increased, so that the problem of thrombus escape is not likely to occur during the thrombus removal process.

[0022] 2. The utility model provides a thrombus removal stent, wherein the outer stent has a plurality of first mesh units for allowing thrombi to enter, and the inner stent has a plurality of second mesh units for allowing thrombi to enter, the size of the second mesh units is larger than the size of the first mesh units, and the second mesh units can further hold the thrombi entering from the first mesh units, that is, the thrombi can be fixed by both the outer stent and the inner stent at the same time.

[0023] 3. The utility model provides a thrombus removal stent, in which the inner layer stent can move relative to the outer layer stent, and accordingly, the position of the second mesh unit relative to the first mesh unit changes, so that the thrombus that enters the second mesh unit and the first mesh unit at the same time forms a dislocation card, further enhancing the fixation ability of the thrombus.

[0024] 4. The utility model provides a thrombus removal stent. When a first thrombus locating portion is provided on an outer layer stent and a second thrombus locating portion is provided on an inner layer stent at the same time, the first thrombus locating portion and the second thrombus locating portion are relatively arranged inwardly and outwardly in an extending direction, respectively locating different positions of the thrombus, which can better achieve the thrombus fixation effect.

[0025] 5. The utility model provides a thrombus removal stent, wherein the first barb points to the proximal end of the outer stent, and then after the first barb is inserted into the thrombus, it will limit the thrombus from moving toward the distal end of the outer stent, and can drive the thrombus to move toward the proximal end during the thrombus removal process. The second barb points to the proximal end of the inner stent, and then after the second barb is inserted into the thrombus, it will limit the thrombus from moving toward the distal end of the inner stent, and can drive the thrombus to move toward the proximal end during the thrombus removal process.

[0026] 6. The utility model provides a thrombus removal bracket, in which the first barb and the second barb are staggeredly arranged, so that the thrombus can be better located from multiple points and angles, and the thrombus can be further stabilized. The first barb and the second barb cooperate with each other, and the fixation effect on the thrombus is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 A schematic diagram of the structure of a thrombus removal bracket provided by the utility model from a first perspective;

[0029] Figure 2 A schematic diagram of the structure of a thrombus removal bracket provided by the utility model from a second viewing angle;

[0030] Figure 3 A side view of a thrombus removal bracket provided by the utility model;

[0031] Figure 4 A schematic diagram of the structure of an outer layer support of a thrombus removal support provided by the utility model;

[0032] Figure 5 A schematic structural diagram of an inner layer support of a thrombus removal support provided by the utility model.

[0033] Reference numerals:

[0034] 1. Outer layer support, 11. First barb, 12. First push wire, 2. Inner layer support, 21. Second barb, 22. Second push wire, 3. Clamping position. DETAILED DESCRIPTION

[0035] The technical solution of the utility model will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0036] In the description of the present invention, it should be noted that the terms "inside" and "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0037] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the term "distal end" generally refers to the end of the medical implant away from the operator; "proximal end" is the opposite of "distal end" and refers to the end of the medical implant close to the operator. The term "radial end" refers to the direction perpendicular to the axis of the medical implant. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0039] Stroke is a disease in which brain tissue is damaged due to sudden rupture of blood vessels in the brain or blockage of blood vessels, which prevents blood from flowing into the brain. It includes ischemic stroke and hemorrhagic stroke. Stroke is one of the main diseases that cause death and disability in humans. Since 2015, many clinical trials at home and abroad have shown that endovascular mechanical thrombectomy for acute ischemic stroke has good postoperative results and a higher clinical recovery rate than the simple intravenous thrombolysis group. Therefore, endovascular thrombectomy is unanimously recommended as the first choice for patients with acute ischemic stroke caused by large vessel occlusion.

[0040] Intracranial artery thrombectomy is actually a stent thrombectomy. Its principle is to use microcatheter technology. The stent thrombectomy device passes through the arterial channel in the body along the lower limb artery to reach the intracranial artery. Then the thrombectomy device at the front of the catheter actively "captures" the blood clot blocking the blood vessel and restores blood vessel patency. During the operation, the doctor only needs to make a small incision of a few millimeters in the patient's thigh to deliver the stent into the blood vessel to the site of the disease, saving the patient from the pain of undergoing craniotomy.

[0041] The current thrombectomy stent can remove blood clots in arteries, but because the thrombectomy of the thrombectomy stent is completely dependent on the embedding of the thrombus by the stent, a large number of thrombi are not firmly embedded. During the thrombectomy process, the thrombus escapes, and the thrombectomy stent needs to be used repeatedly.

[0042] Based on this, the utility model provides a thrombus removal stent, which uses the clamping position formed between the inner stent and the outer stent to achieve embedded capture of the thrombus. The utility model adopts a double-layer stent design, each layer of the stent is a multi-mesh unit design, the outer stent is designed with a first barb pointing inward and pointing to the proximal end, and the inner stent is designed with a second barb pointing outward and pointing to the proximal end. The inner and outer layer barbs are staggered and arranged to stably embed the thrombus, effectively reducing the movement of the thrombus, and the problem of thrombus escape is not likely to occur during the thrombus removal process.

[0043] The specific embodiments of the present invention are described in detail below in conjunction with the thrombus removal bracket of the present invention.

[0044] like Figures 1 to 5 As shown, this embodiment discloses a thrombus removal stent, comprising an outer stent 1 and an inner stent 2. The inner stent 2 is arranged inside the outer stent 1, and can be coaxially arranged or non-coaxially arranged.

[0045] The outer layer stent 1 has a first contracted configuration of radial contraction and a first expanded configuration of radial expansion. When the radial restraining force is removed, the first contracted configuration is transformed into the first expanded configuration; when the radial restraining force is applied, the first expanded configuration is transformed into the first contracted configuration.

[0046] The inner layer stent 2 has a second contracted configuration of radial contraction and a second expanded configuration of radial expansion. When the radial restraining force is removed, the second contracted configuration changes to the second expanded configuration; when the radial restraining force is applied, the second expanded configuration changes to the second contracted configuration.

[0047] When the outer layer stent 1 is in the first expanded configuration state, and when the inner layer stent 2 is in the second expanded configuration state, the inner layer stent 2 and the outer layer stent 1 have a distance in the radial direction (similar to the part left after a small circle is dug out from a large circle), and the outer wall of the inner layer stent 2 and the inner wall of the outer layer stent 1 form a clamping position 3 for fixing the thrombus.

[0048] In the above-mentioned thrombus removal stent, the radial expansion of the inner stent 2 occurs simultaneously with the radial expansion of the outer stent 1, and the clamping position 3 formed between the inner stent 2 and the outer stent 1 is configured to achieve embedded capture of the thrombus. The thrombus is clamped by the inner stent 2 and the outer stent 1, and the strength of the combination with the thrombus removal stent is increased, so that the problem of thrombus escape is less likely to occur during the thrombus removal process.

[0049] In some embodiments, the outer stent 1 is composed of a plurality of stent ribs, and the inner stent 2 is composed of a plurality of stent ribs. Both the outer stent 1 and the inner stent 2 are multi-mesh stents, that is, the outer stent 1 and the inner stent 2 are in a mesh tube structure. The outer stent 1 has a plurality of first mesh units that can allow thrombi to enter, and the inner stent 2 has a plurality of second mesh units that can allow thrombi to enter. The first mesh unit and the second mesh unit are respectively surrounded by at least two curved stent ribs, and the first mesh unit and the second mesh unit are irregular holes. The area of ​​the second mesh unit is larger than the first mesh unit, that is, the size of the second mesh unit is larger than the size of the first mesh unit, and thus the inner stent 2 does not block the thrombus from entering the mesh of the outer stent 1, and at the same time, the thrombus can pass through the mesh of the outer stent 1 into the mesh of the inner stent 2, and the second mesh unit can further hold the thrombus entering from the first mesh unit, so that the thrombus can be fixed by the outer stent 1 and the inner stent 2 at the same time.

[0050] In some embodiments, a first thrombus locating portion is provided on the outer layer stent 1 to extend inwardly, and the first thrombus locating portion can be inserted into the thrombus to locate the thrombus; and / or a second thrombus locating portion is provided on the inner layer stent 2 to extend outwardly, and the second thrombus locating portion can be inserted into the thrombus to locate the thrombus. In this embodiment, the first thrombus locating portion can be provided only on the outer layer stent 1, or the second thrombus locating portion can be provided only on the inner layer stent 2, or the first thrombus locating portion can be provided on the outer layer stent 1 and the second thrombus locating portion can be provided on the inner layer stent 2 at the same time. When the first thrombus locating portion is provided on the outer layer stent 1 and the second thrombus locating portion is provided on the inner layer stent 2 at the same time, the first thrombus locating portion and the second thrombus locating portion are provided opposite to each other in the extension direction inside and outside, and different positions of the thrombus are located respectively, so as to better achieve the fixation effect of the thrombus.

[0051] The first thrombus locating portion and / or the second thrombus locating portion can undergo elastic deformation in the radial direction, thereby enabling the first thrombus locating portion and / or the second thrombus locating portion to adaptively deform when they are pressed and gripped in the microcatheter. When the outer layer stent 1 and the inner layer stent 2 are released from the microcatheter, the first thrombus locating portion and / or the second thrombus locating portion return to a normal state.

[0052] like Figure 4As shown, in some embodiments, the first thrombus positioning portion includes at least one first barb 11, and the first barb 11 points to the proximal end of the outer stent 1. In this embodiment, because the first barb 11 points to the proximal end of the outer stent 1, the first barb 11 will limit the movement of the thrombus toward the distal end of the outer stent 1 after being inserted into the thrombus, and can drive the thrombus to move toward the proximal end during the thrombus removal process.

[0053] When the first thrombus positioning portion includes a plurality of first barbs 11 , the plurality of first barbs 11 are arranged on the outer layer stent 1 at intervals.

[0054] like Figure 5 As shown, in some embodiments, the second thrombus positioning portion includes at least one second barb 21, and the second barb 21 points to the proximal end of the inner stent 2. In this embodiment, because the second barb 21 points to the proximal end of the inner stent 2, the second barb 21 will limit the movement of the thrombus toward the distal end of the inner stent 2 after being inserted into the thrombus, and can drive the thrombus to move toward the proximal end during the thrombus removal process.

[0055] When the second thrombus positioning portion includes a plurality of second barbs 21 , the plurality of second barbs 21 are arranged on the inner layer stent 2 at intervals.

[0056] In some embodiments, after the outer stent 1 and the inner stent 2 are radially expanded, the first barbs 11 and the second barbs 21 point to each other, and the first barbs 11 and the second barbs 21 are arranged in a staggered manner. In this embodiment, the staggered first barbs 11 and the second barbs 21 can locate the thrombus from multiple points and angles, further stabilize the thrombus, and the first barbs 11 and the second barbs 21 cooperate with each other to better fix the thrombus.

[0057] In some embodiments, the inner layer support 2 can move relative to the outer layer support 1, and accordingly, the position of the second mesh unit relative to the first mesh unit changes, and the thrombus that enters the second mesh unit and the first mesh unit at the same time is dislocated, further enhancing the fixation ability of the thrombus. And when the first barb 11 is extended inwardly on the outer layer support 1, and the second barb 21 is extended outwardly on the inner layer support 2, the movement of the inner layer support 2 relative to the outer layer support 1 will change the relative position of the first barb 11 and the second barb 21. When the distance between the first barb 11 and the second barb 21 becomes smaller, it can have a better clamping effect.

[0058] like Figure 1As shown, in some embodiments, a first push wire 12 is disposed at the proximal end of the outer stent 1, and a second push wire 22 is disposed at the proximal end of the inner stent 2, and the first push wire 12 and the second push wire 22 are disposed relatively independently. When the outer stent 1 is in the first expansion configuration and the inner stent 2 is in the second expansion configuration, the outer stent 1 can be moved by the first push wire 12, and the inner stent 2 can be moved by the second push wire 22.

[0059] More specifically, the inner layer support 2 can move relative to the outer layer support 1 in ways including but not limited to axial movement, rotation around the axial direction, and change of the radial relative position of the two. It should be noted that the ways of "axial movement, rotation around the axial direction, and change of the radial relative position of the two" can be performed separately or in combination of two or more ways.

[0060] When the outer stent 1 and the inner stent 2 are both in the expanded configuration, the first push wire 12 can be fixed and the second push wire 22 can be controlled to move axially, thereby causing the inner stent 2 to move axially relative to the outer stent 1, so that the position of the second mesh unit relative to the first mesh unit changes to form a misaligned card, which can enhance the fixation effect on the thrombus on the one hand, and more effectively prevent the thrombus from escaping from the outer stent 1 on the other hand.

[0061] When the outer stent 1 and the inner stent 2 are both in the expanded configuration, the first push wire 12 can be fixed and the second push wire 22 can be controlled to rotate axially, thereby controlling the inner stent 2 to rotate axially, so that the position of the second mesh unit relative to the first mesh unit changes relatively to form a misalignment card.

[0062] When the outer layer stent 1 and the inner layer stent 2 are both in the expanded configuration, the inner layer stent 2 can be controlled to move radially, thereby changing the radial relative position between the inner layer stent 2 and the outer layer stent 1, so that the radial spacing of the second mesh unit relative to the first mesh unit changes (that is, the radial positions of the large circle and the small circle change), thereby enhancing the fixation effect on the thrombus.

[0063] In some embodiments, the first push wire 12 and the second push wire 22 are further provided with a limiting portion to prevent excessive movement between the inner layer support 2 and the outer layer support 1. The limiting portion can be in the form of a baffle / block, a limiting groove / limiting hole to limit the distance of axial movement and / or limit the angle of rotation around the axial direction.

[0064] In some embodiments, a developing coating is provided on the surface of the outer stent 1 and / or the inner stent 2. In this embodiment, the developing coating can display the position of the entire stent, thereby facilitating the operator to observe whether the entire stent has reached the lesion position.

[0065] like Figure 3As shown, in some embodiments, the clamping position 3 is an annular clamping position, which is convenient for clamping the thrombus in all directions and fixating the thrombus more stably.

[0066] The specific working process of the above-mentioned thrombectomy stent is as follows:

[0067] When in use, the microcatheter holding the thrombus removal stent (the outer stent 1 is in the first contracted configuration of radial contraction, and the inner stent 2 is in the second contracted configuration of radial contraction) is passed through the thrombus so that the distal end thereof is at a certain distance from the distal end of the thrombus. The first push wire 12 and the second push wire 22 are fixed, and the microcatheter is withdrawn. The inner stent 2 and the outer stent 1 are released at the same time (the outer stent 1 is in the first expanded configuration of radial expansion, and the inner stent 2 is in the second expanded configuration of radial expansion). The clamping position 3 formed between the inner stent 2 and the outer stent 1 realizes the embedded capture of the thrombus. The relative movement of the first push wire 12 and the second push wire 22 changes the position of the second mesh unit relative to the first mesh unit, thereby increasing the bonding strength between the thrombus and the thrombus removal stent. Finally, the thrombus removal stent is withdrawn to pull out the thrombus together, and the thrombus removal operation is completed.

[0068] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the scope of protection of the invention of the utility model.

Claims

1. A thrombus removal stent, characterized in that: include: The outer layer stent (1) has a radially contracted first contracted configuration and a radially expanded first expanded configuration; The inner layer stent (2) has a second contracted configuration of radial contraction and a second expanded configuration of radial expansion; The inner layer support (2) is arranged inside the outer layer support (1); When the outer layer stent (1) is in the first expansion configuration and the inner layer stent (2) is in the second expansion configuration, the inner layer stent (2) and the outer layer stent (1) have a distance in the radial direction, and a clamping position (3) for fixing the thrombus is formed between the outer wall of the inner layer stent (2) and the inner wall of the outer layer stent (1).

2. The thrombus removal stent according to claim 1, characterized in that: The outer layer stent (1) has a plurality of first mesh units that allow thrombus to enter, and the inner layer stent (2) has a plurality of second mesh units that allow thrombus to enter, and the size of the second mesh units is larger than the size of the first mesh units.

3. The thrombus removal stent according to claim 1, characterized in that: The inner layer support (2) is capable of moving relative to the outer layer support (1).

4. The thrombus removal stent according to claim 3, characterized in that: The proximal end of the outer layer stent (1) is provided with a first pushing wire (12), and the proximal end of the inner layer stent (2) is provided with a second pushing wire (22).

5. The thrombus removal stent according to any one of claims 1 to 4, characterized in that: A first thrombus positioning portion is provided on the outer layer support (1) and extends inwardly; and / or a second thrombus positioning portion is provided on the inner layer support (2) and extends outwardly.

6. The thrombus removal stent according to claim 5, characterized in that: The first thrombus positioning portion and / or the second thrombus positioning portion may be elastically deformed in a radial direction.

7. The thrombus removal stent according to claim 5, characterized in that: A first thrombus positioning portion is provided inwardly extending from the outer layer stent (1), and the first thrombus positioning portion includes at least one first barb (11), and the first barb (11) points to the proximal end of the outer layer stent (1).

8. The thrombus removal stent according to claim 5, characterized in that: A second thrombus positioning portion is provided on the inner layer stent (2) and extends outwardly. The second thrombus positioning portion includes at least one second barb (21). The second barb (21) points to the proximal end of the inner layer stent (2).

9. The thrombus removal stent according to claim 5, characterized in that: The outer layer stent (1) is provided with a first barb (11) extending inwardly, and the inner layer stent (2) is provided with a second barb (21) extending outwardly. After the outer layer stent (1) and the inner layer stent (2) are radially expanded, the first barb (11) and the second barb (21) are arranged in a staggered manner.

10. The thrombus removal stent according to any one of claims 1 to 4, characterized in that: The clamping position (3) is an annular clamping position.

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