Embolectomy stent for ischemic stroke

Abstract

The invention provides a thrombus extraction stent for ischemic stroke, and the thrombus extraction stent comprises a stent which is a frame structure for fixing thrombus; the core wire is connected to the far end of the stent; the sleeve is connected to the near end of the support; the handle is provided with a button capable of sliding in the front-and-back direction relative to the handle or rotating relative to the handle, the sleeve is connected to the button, the sleeve can move in the front-and-back direction by operating the button, and therefore force is applied to the support, and when the button is pushed forwards, the sleeve can move in the front-and-back direction. When the button is pulled or pulled backwards, the support can expand, and when the button is pulled backwards or pulled, the support can contract. By the adoption of the technical scheme, when the stent shrinks, the near end of the stent moves, and in the process that thrombus is collected into the guide catheter, the thrombus and the stent can be stably fixed.

Description

Technical Field

[0001] This application belongs to the field of medical devices, and particularly relates to a thrombectomy stent for ischemic stroke. Background Art

[0002] Ischemic stroke, also known as cerebral infarction, is called stroke or apoplexy in traditional Chinese medicine. This disease is caused by blood supply disorders in local brain tissue regions due to various reasons, leading to ischemic and hypoxic pathological necrosis of brain tissue, and then corresponding neurological deficits clinically. According to different pathogenesis, cerebral infarction is divided into main types such as cerebral thrombosis, cerebral embolism, and lacunar infarction.

[0003] Cerebral thrombosis is the most common type of cerebral infarction, accounting for about 60% of all cerebral infarctions. Therefore, the so-called "cerebral infarction" actually refers to cerebral thrombosis.

[0004] Interventional treatment includes intravascular mechanical thrombectomy and arterial thrombolysis.

[0005] (1) Intravascular mechanical thrombectomy can significantly improve the prognosis of patients with ischemic stroke caused by acute large artery occlusion. The 2018 Guidelines for the Diagnosis and Treatment of Acute Ischemic Stroke recommend that conditional medical institutions be implemented by a clinically trained medical team, and strictly master the indications for intravascular mechanical thrombectomy.

[0006] (2) Arterial thrombolysis. Arterial thrombolysis makes the thrombolytic drug directly reach the local thrombus. Theoretically, the vascular recanalization rate is higher than that of intravenous thrombolysis, and the bleeding risk is reduced. However, due to the lack of clinical evidence to confirm the benefit of arterial thrombolysis, currently, the first-line intravascular treatment is mechanical thrombectomy.

[0007] For patients with stroke who are sent to the hospital in time, the conventional treatment plan is drug thrombolysis. However, the best window time for drug thrombolysis (the time from onset to treatment) is within 4 hours. Such a short thrombolysis time window results in less than 10% of patients being able to receive effective thrombolytic treatment; secondly, drug thrombolysis is basically ineffective for large thrombi.

[0008] To solve the above problems of drug thrombolysis, the method of mechanically removing thromboembolism has become a research hotspot in recent years:

[0009] In the invention patent "Intravascular Thrombus and Embolus Remover" of CN101396295A, there is a thrombus remover with a thrombus removal spring and a basket in a contracted or released state. The basket is located at the distal end of the thrombus remover, catches the thrombus by winding the thrombus removal spring, and takes out the blood clots and thrombus fragments generated during the thrombectomy process together to protect the distal end of the blood vessel.

[0010] In the utility model "thrombus remover" of CN200620164685.4, a three-claw umbrella with two long and one short claws with elastic memory function and a net attached to the periphery forms a circular structure of the thrombus remover. The three claws are closed by pulling the push-pull rod outward to collect the thrombus in the umbrella part and return it to the outer sleeve to remove the thrombus. However, the above obvious defect is that when the thrombus cannot be directly seen, the basket or net-shaped capture device often cannot cover the blood clot, resulting in failure of thrombus removal.

[0011] The most commonly used thrombus removal systems in clinical practice are Solitaire from ev3 in the United States and TrevoDevice from Stryker in the United States. The designs of the two are very similar, and the methods of use are almost the same. The entire device is contained in a microcatheter with an inner diameter of less than 0.6 mm. During interventional surgery, the doctor pushes the microcatheter with the device over the thrombus and then pushes out the core device. After the device has engulfed the thrombus, it begins to slowly withdraw the microcatheter and transfer the engulfed thrombus to a guide catheter with a larger inner diameter.

[0012] like Figure 1 As shown, there is a thrombectomy stent that can be controlled to expand in the prior art, which includes a stent 1, a core wire 2, a sleeve 3, a handle 4 and a button 5. The button 5 can be slidably mounted on the handle 4 along the front-to-back direction X relative to the handle 4, one end of the sleeve 3 is connected to the proximal end of the stent 1, and the other end of the sleeve 3 is connected to the handle 4. One end of the core wire 2 is connected to the distal end of the stent 1, and the other end of the core wire 2 is connected to the button 5. The stent 1 can be expanded by withdrawing the button 5, and the stent 1 can be contracted by pushing the button 5 forward. The distal end of the stent 1 can be controlled by the button 5 to move toward the proximal end of the stent 1 under the traction of the core wire 2, so that the stent 1 can be expanded.

[0013] The above-mentioned controllable expansion thrombectomy stent requires that stent 1 be moderately contracted before being withdrawn into the guide catheter to facilitate the collection of the thrombus into the guide catheter. However, during the contraction of stent 1, the proximal end of stent 1 is fixed and the distal end of stent 1 moves forward, causing the thrombus to move along with stent 1 toward the distal end of stent 1, resulting in the thrombus easily falling off. Summary of the invention

[0014] The present application aims to provide a thrombus removal stent, which makes it difficult for the thrombus to fall off the stent when the stent is contracted.

[0015] The present application proposes a thrombectomy stent for ischemic stroke, the thrombectomy stent comprising:

[0016] A stent, wherein the stent is a frame structure for fixing a thrombus;

[0017] A core wire connected to the distal end of the stent;

[0018] a sleeve connected to the proximal end of the stent; and

[0019] A handle, on which a button is installed that can slide relative to the handle in the front - rear direction or can rotate relative to the handle. The sleeve is connected to the button. By operating the button, the sleeve can be moved in the front - rear direction, thereby applying a force to the stent, where

[0020] when the button is pushed forward, the stent can expand,

[0021] when the button is pulled backward or toggled, the stent can contract.

[0022] Preferably, when using the thrombectomy stent, the handle is for gripping.

[0023] Preferably, the sleeve is tubular and the sleeve is sleeved on the core wire.

[0024] Preferably, the handle and / or the button are provided with a locking structure, and the locking structure locks the button relative to the handle.

[0025] Preferably, the stent has multiple layers of sub - stents.

[0026] Preferably, the handle is provided with scale marks located beside the button, which are used to mark the diameter of the stent when the button is in different positions.

[0027] Preferably, the button is provided with a pointer that points to the scale marks.

[0028] Preferably, a protection part is formed at the distal end of the stent, and the protection part is bent relative to the sleeve.

[0029] Preferably, the hardness of the distal part of the sleeve is less than the hardness of the proximal part of the sleeve.

[0030] Preferably, the stent is a woven or etched mesh structure.

[0031] By adopting the above - mentioned technical solution, when the stent contracts, the proximal end of the stent is moved, and during the process of the thrombus being received into the guiding catheter, the thrombus and the stent can be stably fixed. Brief Description of the Drawings

[0032] Figure 1 Shows a schematic structural diagram of a prior - art thrombectomy stent.

[0033] Figure 2 Shows a schematic structural diagram of a thrombectomy stent according to an embodiment of the present application.

[0034] Figure 3 Shows a partial enlarged view of a thrombectomy stent (stent expanded state) and a thrombus according to an embodiment of the present application.

[0035] Figure 4 Shows a partial enlarged view of a thrombectomy stent (stent contracted state) and a thrombus according to an embodiment of the present application.

[0036] Figure 5 Shows a schematic structural diagram of a stent, a core wire, and a cannula of a thrombectomy device according to an embodiment of the present application.

[0037] Figure 6 Shows an enlarged structural view of a stent of a thrombectomy device according to an embodiment of the present application.

[0038] Figure 7 Shows a schematic structural diagram of another stent of a thrombectomy device according to an embodiment of the present application.

[0039] Figure 8 Shows a schematic structural diagram of a stent, a core wire, and a cannula of a thrombectomy device according to another embodiment of the present application.

[0040] Figure 9 Shows a schematic structural diagram of a stent of a thrombectomy device according to another embodiment of the present application.

[0041] Figure 10 Shows a schematic structural diagram of another stent of a thrombectomy device according to another embodiment of the present application.

[0042] Figure 11 Shows a schematic structural diagram of a stent, a core wire, and a cannula of a thrombectomy device according to yet another embodiment of the present application.

[0043] Figure 12 Shows a schematic structural diagram of a stent of a thrombectomy device according to yet another embodiment of the present application.

[0044] Description of Reference Numerals

[0045] 1 Stent

[0046] 2 Core Wire

[0047] 3 Cannula

[0048] 4 Handle

[0049] 5 Button

[0050] 100 Thrombus

[0051] X Front - Back Direction. Detailed Embodiments

[0052] To more clearly elaborate on the above-mentioned objects, features, and advantages of the present application, the specific implementation manners of the present application will be described in detail in conjunction with the accompanying drawings in this section. In addition to the various implementation manners described in this section, the present application can also be implemented in other different ways. Without departing from the spirit of the present application, those skilled in the art can make corresponding improvements, deformations, and substitutions. Therefore, the present application is not limited by the specific embodiments disclosed in this section. The protection scope of the present application shall be subject to the claims.

[0053] As Figures 2 to 4 shown, the present application proposes a thrombectomy stent, which includes a stent 1, a core wire 2, a sleeve 3, a handle 4, and a button 5.

[0054] In the following description, one end of the stent 1 close to the handle 4 (the operator) is referred to as the proximal end of the stent 1 ( Figure 2 the right end), and the end of the stent 1 far from the handle 4 (the operator) is referred to as the distal end of the stent 1 ( Figure 2 the left end).

[0055] One end of the core wire 2 is connected to the distal end of the stent 1, and the other end of the core wire 2 is connected to the handle 4.

[0056] One end of the sleeve 3 is connected to the proximal end of the stent 1, and the other end of the sleeve 3 is connected to the button 5.

[0057] The sleeve 3 can be a hollow cylindrical shape. The sleeve 3 is sleeved on the core wire 2, and the sleeve 3 can slide relative to the core wire 2 in the front-back direction X.

[0058] Furthermore, the sleeve 3 can be made of woven metal wires, can be made of a metal tube, or can be formed by a combination of metal wires and a metal tube. The metal tube can be cut (such as laser cutting) along the axial direction of the tube wall to form a spiral structure. This spiral structure can adjust the hardness of the metal tube, so that the sleeve 3 has better anti-bending properties. At different parts of the sleeve 3, the pitch of the spiral structure can be different, so that the corresponding section of the sleeve 3 has appropriate hardness. For example, the pitch of the sleeve 3 at the proximal end is smaller, and the pitch of the sleeve 3 at the distal end is larger.

[0059] Generally, the hardness of the distal part of the sleeve 3 is less than the hardness of the proximal part of the sleeve 3. The distal part of the sleeve 3 is softer and easier to move in the blood vessel, and the proximal part of the sleeve 3 is harder and easier to transmit the pushing force. The distal end of the sleeve 3 (the part close to the stent 1) uses a softer structure (such as woven metal wires, a metal tube with a spiral structure, or a combination of the two); the proximal end of the sleeve 3 (the part close to the handle 4) uses a harder structure (such as a metal tube without a spiral structure).

[0060] The handle 4 is installed with a button 5 that can slide relative to the handle 4 in the front-rear direction X. By pushing and pulling the button 5 in the front-rear direction X, the sleeve 3 can be driven to move in the front-rear direction X, so that the proximal end of the stent 1 moves in the front-rear direction X. When using the thrombectomy stent, the handle 4 is for holding, and the button 5 can be controlled by fingers.

[0061] The handle 4 and / or the button 5 are provided with a locking structure, and the locking structure locks the button 5 relative to the handle 4, so that the shape of the stent 1 can be kept unchanged.

[0062] Preferably, the handle 4 can be provided with scale marks, and the scale marks are located beside the button 5. The scale marks are used to mark the relationship between the displacement of the button 5 and the diameter of the stent 1. The button 5 is provided with a pointer, and the pointer points to the scale marks, so that the position of the button 5 can accurately correspond to the scale marks.

[0063] The stent 1 can be a mesh structure formed by weaving or etching, etc. The stent 1 can be deformed by applying a force in the front-rear direction X. When the two end portions of the stent 1 approach under the action of an external force, the stent 1 can expand, making the diameter of the stent 1 larger. The expanded stent 1 can be in a spindle shape with a thick middle and thin ends.

[0064] A protection part (also called a tip) is formed at the distal end of the stent 1. The protection part is bent relative to the sleeve 3. The protection part can be made of a soft material, which is beneficial for the stent 1 to turn in the blood vessel and avoid damaging the blood vessel by the stent 1. It can be understood that the protection part can also be straight when not affected by an external force and does not necessarily need to be bent relative to the sleeve 3.

[0065] When the operation button 5 moves forward, the sleeve 3 can push the proximal end of the stent 1 close to the distal end of the stent 1, so that the stent 1 expands.

[0066] When the operation button 5 moves backward, the sleeve 3 can pull the proximal end of the stent 1 away from the distal end of the stent 1, so that the stent 1 contracts.

[0067] The stent 1 can include multiple layers of sub-stents. When the stent 1 expands or contracts, the multiple layers of sub-stents can expand or contract together. The multiple layers of sub-stents can make the thrombus fixed stably with the stent 1, and the thrombus is not easy to fall off.

[0068] Specifically, as Figures 5 to 7As shown in the figure, the stent 1 includes an inner thrombus extraction net 11 and an outer thrombus extraction net 12. In a state without external force restraint, the radial dimension of the outer thrombus extraction net 12 is generally larger than that of the inner thrombus extraction net 11, and the outer thrombus extraction net 12 wraps around the outside of the inner thrombus extraction net 11. The inner thrombus extraction net 11 and the outer thrombus extraction net 12 can be different types of thrombus extraction nets. The inner thrombus extraction net 11 can be an adjustable thrombus extraction net, and the inner thrombus extraction net 11 can be woven, also known as a woven thrombus extraction net. The outer thrombus extraction net 12 can be a self-expanding thrombus extraction net, and the outer thrombus extraction net 12 can be engraved, also known as an engraved thrombus extraction net. Both the inner thrombus extraction net 11 and the outer thrombus extraction net 12 can be made of nitinol, and nitinol has elasticity. In different parts of the stent 1, the density of its mesh structure can be different.

[0069] The proximal end of the inner thrombus extraction net 11 is connected to the sleeve 3, and the distal end of the inner thrombus extraction net 11 is connected to the core wire 2. The core wire 2 can slide relative to the sleeve 3 in the front-back direction. Pulling the core wire 2 proximally by the operation button 5 can cause the inner thrombus extraction net 11 to expand into a shape with thinner ends and thicker middle, enabling the inner thrombus extraction net 11 to embed into the thrombus.

[0070] The proximal end of the outer thrombus extraction net 12 is connected to the sleeve 3. After the outer thrombus extraction net 12 removes the restraint of the guiding catheter, the distal end of the outer thrombus extraction net 12 can expand by relying on its own memory performance and thus embed into the thrombus.

[0071] One end of the core wire 2 is connected to the distal end of the inner thrombus extraction net 11, and the other end of the core wire 2 is connected to the button 5. One end of the sleeve 3 is connected to the proximal ends of the inner thrombus extraction net 11 and the outer thrombus extraction net 12, and the other end of the sleeve 3 is connected to the handle 4.

[0072] The inner thrombus extraction net 11 can be deformed by applying a force in the front-back direction. When the two ends of the inner thrombus extraction net 11 approach under the action of an external force, the inner thrombus extraction net 11 can expand, increasing the diameter of the inner thrombus extraction net 11. The expanded inner thrombus extraction net 11 can be in a spindle shape with a thicker middle and thinner ends. The inner thrombus extraction net 11 can have elasticity, and the expanded inner thrombus extraction net 11 can tend to return to its original state under the action of elastic force.

[0073] Before use, both the inner thrombus extraction net 11 and the outer thrombus extraction net 12 are in a contracted state. During use, the outer thrombus extraction net 12 expands and embeds into the thrombus by relying on the shape memory performance of nitinol after removing the restraint, and the inner thrombus extraction net 11 is expandably adjusted through the core wire 2 and embeds into the thrombus.

[0074] In a possible implementation manner, as Figures 8 to 10 shown in the figure, the stent 1 includes an inner thrombus extraction net 11 and an outer thrombus extraction net 12. The inner thrombus extraction net 11 and the outer thrombus extraction net 12 can be the same type of thrombus extraction net, and both the inner thrombus extraction net 11 and the outer thrombus extraction net 12 can be woven adjustable thrombus extraction nets.

[0075] The cannula 3 includes an inner cannula 31 and an outer cannula 32. The outer cannula 32 is sleeved on the inner cannula 31, and the core wire 2 passes through the inner cannula 31. The proximal end of the inner thrombus retrieval net 11 is connected to the inner cannula 31, and the distal end of the inner thrombus retrieval net 11 is connected to the core wire 2. The proximal end of the outer thrombus retrieval net 12 is connected to the outer cannula 32, and the distal end of the outer thrombus retrieval net 12 is connected to the core wire 2.

[0076] In a possible implementation, as Figure 11 and Figure 12 shown, the stent 1 includes an inner thrombus retrieval net 11 and an outer thrombus retrieval net 12. The inner thrombus retrieval net 11 and the outer thrombus retrieval net 12 can be different types of thrombus retrieval nets. The inner thrombus retrieval net 11 can be a self-expanding thrombus retrieval net, and the outer thrombus retrieval net 12 can be an adjustable thrombus retrieval net.

[0077] The proximal ends of both the inner thrombus retrieval net 11 and the outer thrombus retrieval net 12 are connected to the cannula 3, and the distal end of the outer thrombus retrieval net 12 is connected to the core wire 2.

[0078] It can be understood that the inner thrombus retrieval net 11 cannot control the degree of expansion. If the size is too large, it may interfere with the outer thrombus retrieval net 12. Therefore, the inner thrombus retrieval net 11 should not be too large. The inner thrombus retrieval net 11 is restricted by the outer thrombus retrieval net 12. After the outer thrombus retrieval net 12 expands controllably, the inner thrombus retrieval net 11 will have sufficient space to expand.

[0079] Preferably, the stent 1 can be made of a material that can be visualized by a visualization instrument, or the stent 1 can include a visualization material. For example, it includes a plurality of visualization points. In this way, the stent 1 can be observed through the visualization instrument.

[0080] As Figures 2 to 4 shown, during the operation, the stent 1 first passes through the thrombus 100, and then the button 5 is pushed forward to move the cannula 3 forward. The stent 1 expands and fixes the thrombus 100 to the stent 1. The thrombus 100 is moved along the blood vessel towards the extracorporeal direction and gradually approaches the opening of the guiding catheter. Then, the handle 4 is held to retract the entire thrombus retrieval stent, so that the thrombus 100 can be retrieved through the guiding catheter. Before the stent 1 and the thrombus 100 enter the guiding catheter, the stent 1 is contracted to a certain extent to facilitate the entry of the stent 1 and the thrombus 100 into the guiding catheter. The handle 4 remains stationary, that is, when the overall position of the thrombus retrieval stent remains unchanged, the button 5 is pulled backward, and it is easy to control the backward movement of the cannula 3. When the stent 1 contracts, the distal position of the stent 1 remains unchanged, the proximal end of the stent 1 moves towards the guiding catheter, the thrombus 100 is stably fixed to the stent 1, the thrombus 100 is not easily detached, and even if it is detached, the thrombus 100 can be easily received into the guiding catheter as the proximal end of the stent 1 moves.

[0081] It can be understood that the button is not limited to moving relative to the handle 4 along the front-rear direction X. Instead, the button can be configured to be rotatable relative to the handle 4. At this time, the button can also be referred to as a trigger. At this time, for example, when the button is rotated backward (or pulled, pulled) away from the bracket 1, the button drives the sleeve 3 to move backward (move proximally), thereby causing the bracket 1 to contract.

[0082] Although the present application has been described in detail using the above embodiments, it is obvious to those skilled in the art that the present application is not limited to the embodiments described in this specification. The present application can be modified and implemented as a variant embodiment without departing from the gist and scope of the present application determined by the claims. Therefore, the descriptions in this specification are for illustrative purposes and do not have any restrictive meaning for the present application.

Claims

1. A thrombectomy stent for ischemic stroke, characterized in that, the thrombectomy stent comprises: a stent (1), the stent (1) being a frame structure for fixing thrombus; a core wire (2), the core wire (2) being connected to the distal end of the stent (1); a sleeve (3), the sleeve (3) being connected to the proximal end of the stent (1); and a handle (4), the handle (4) being provided with a button that can slide relative to the handle (4) in the front-rear direction (X) or can rotate relative to the handle (4), the sleeve (3) being connected to the button (5), and by operating the button (5), the sleeve (3) can be moved in the front-rear direction (X), so as to apply a force to the stent (1) to cause the stent (1) to contract or expand; the stent (1) has multiple layers of sub-stents; the multiple layers of sub-stents at least include an inner thrombus removal mesh (11) and / or an outer thrombus removal mesh (12), and the outer thrombus removal mesh (12) is wrapped outside the inner thrombus removal mesh (11).

2. The thrombectomy stent for ischemic stroke according to claim 1, characterized in that, the inner thrombus removal mesh (11) and the outer thrombus removal mesh (12) are of the same type of stent.

3. The thrombectomy stent for ischemic stroke according to claim 1, characterized in that, the inner thrombus removal mesh (11) and the outer thrombus removal mesh (12) are of different types of stents.

4. The thrombectomy stent for ischemic stroke according to claim 1, characterized in that, the inner thrombus removal mesh (11) is a braided stent.

5. The thrombectomy stent for ischemic stroke according to claim 1, characterized in that, the outer thrombus removal mesh (12) is a braided stent.

6. The thrombectomy stent for ischemic stroke according to claim 1, characterized in that, the outer thrombus removal mesh (12) is a carved thrombus removal mesh.

7. The thrombectomy stent for ischemic stroke according to claim 1, characterized in that, the inner thrombus removal mesh (11) is a carved thrombus removal mesh.

8. The thrombectomy stent for ischemic stroke according to any one of claims 1-7, characterized in that, when using the thrombectomy stent, the handle (4) is used for gripping, when the button is pushed forward, the stent can expand, when the button is pulled backward or toggled, the stent can contract.

9. The thrombectomy stent for ischemic stroke according to claim 1, characterized in that, the sleeve (3) is tubular, the sleeve (3) is sleeved on the core wire (2), and the handle (4) and / or the button (5) is provided with a locking structure, and the locking structure locks the button (5) relative to the handle (4); by the button (5), the distal end of the stent (1) can be controlled to move toward the proximal end of the stent (1) under the traction of the core wire (2) to expand the stent 1.

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