Stent retrievers for ischemic stroke

Abstract

The present application proposes a thrombectomy stent for ischemic stroke, the thrombectomy stent comprises: a stent, the stent is a frame structure for fixing a thrombus; a core wire, the core wire is connected to the distal end of the stent; a sleeve, the sleeve is connected to the proximal end of the stent; and a handle, the handle is equipped with a button that can slide in the front-to-back direction relative to the handle or can rotate relative to the handle, the sleeve is connected to the button, and the sleeve can be moved in the front-to-back direction by operating the button, thereby applying force to the stent, wherein when the button is pushed forward, the stent can expand, and when the button is pulled backward or pulled, the stent can shrink. By adopting the above technical solution, when the stent shrinks, the proximal end of the stent moves, and the thrombus and the stent can be fixed and stabilized during the process of the thrombus being taken into the guide catheter.

Description

Technical Field

[0001] The present application belongs to the field of medical equipment, and in particular, relates to a thrombectomy stent for ischemic stroke. Background Art

[0002] Ischemic stroke is also called cerebral infarction, and Chinese medicine calls it stroke or apoplexy. This disease is caused by various reasons that lead to blood supply disorders in the local brain tissue area, resulting in ischemic hypoxic lesions and necrosis of brain tissue, and then produce clinically corresponding neurological dysfunction. Cerebral infarction is divided into major types such as cerebral thrombosis, cerebral embolism and lacunar cerebral infarction according to different pathogenesis.

[0003] Cerebral thrombosis is the most common type of cerebral infarction, accounting for about 60% of all cerebral infarctions. Therefore, what is commonly referred to as "cerebral infarction" actually refers to cerebral thrombosis.

[0004] Interventional treatment includes intravascular mechanical thrombectomy and intra-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 recommends that medical institutions with the necessary conditions and a clinical medical team with standardized training should strictly follow the indications for intravascular mechanical thrombectomy.

[0006] (2) Arterial thrombolysis: Arterial thrombolysis allows thrombolytic drugs to directly reach the thrombus site. Theoretically, the vascular recanalization rate is higher than that of intravenous thrombolysis, and the risk of bleeding is reduced. However, due to the lack of clinical evidence to prove the benefits of arterial thrombolysis, the current first-line intravascular treatment is mechanical thrombectomy.

[0007] For stroke patients who are sent to the hospital in time, the conventional treatment option is drug thrombolysis. However, the optimal 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 larger blood clots.

[0008] In order to solve the above-mentioned problem of drug thrombolysis, mechanical elimination of thromboembolism has become a research hotspot in recent years:

[0009] In the invention patent "Intravascular Thrombus and Embolic Material Removal Device" of CN101396295A, the thrombectomy device has a thrombectomy spring and a net basket in a contracted or released state. The net basket is located at the distal end of the thrombectomy device, and the thrombus is captured by the winding of the thrombectomy spring. The blood clots and thrombus fragments generated during the thrombectomy process are removed together with the net basket 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 is provided with a button that can slide in the front-rear direction relative to the handle or can rotate in the front-rear direction relative to the handle, the sleeve is connected to the button, and the sleeve can be moved in the front-rear direction by operating the button, thereby applying force to the bracket, wherein

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

[0021] When the button is pulled back or flipped, the bracket can be retracted.

[0022] Preferably, when the thrombus removal bracket is used, the handle is used for holding.

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

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

[0025] Preferably, the support has multiple layers of sub-supports.

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

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

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

[0029] Preferably, the hardness of the distal portion of the cannula is less than the hardness of the proximal portion of the cannula.

[0030] Preferably, the stent is a mesh structure formed by weaving or etching.

[0031] By adopting the above technical solution, when the stent contracts, the proximal end of the stent moves, and the thrombus is stably fixed to the stent during the process of being received into the guide tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic structural diagram of a prior art thrombus removal stent is shown.

[0033] Figure 2 A schematic structural diagram of a thrombus removal stent according to an embodiment of the present application is shown.

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

[0035] Figure 4 A partially enlarged view of a thrombus retriever stent (stent contracted state) and a thrombus according to an embodiment of the present application is shown.

[0036] Figure 5 A schematic diagram of the structure of a stent, a core wire and a sleeve of a thrombus removal device according to an embodiment of the present application is shown.

[0037] Figure 6 An enlarged structural view of a bracket of a thrombus removal device according to an embodiment of the present application is shown.

[0038] Figure 7 Another schematic diagram of the support structure of the thrombus removal device according to the embodiment of the present application is shown.

[0039] Figure 8 A schematic structural diagram of a stent, a core wire and a sleeve of a thrombus removal device according to another embodiment of the present application is shown.

[0040] Fig. 9 A schematic structural diagram of a bracket of a thrombus removal device according to another embodiment of the present application is shown.

[0041] Fig.10 A schematic structural diagram of another bracket of a thrombus removal device according to another embodiment of the present application is shown.

[0042] Fig.11 A schematic structural diagram of a stent, a core wire and a sleeve of a thrombus removal device according to another embodiment of the present application is shown.

[0043] Fig.12 A schematic structural diagram of a bracket of a thrombus removal device according to another embodiment of the present application is shown.

[0044] Description of Reference Numerals

[0045] 1 Bracket

[0046] 2 core wire

[0047] 3 Casing

[0048] 4 Handles

[0049] 5 Buttons

[0050] 100 Blood clots

[0051] X Front-to-back direction. DETAILED DESCRIPTION

[0052] In order to more clearly explain the above-mentioned purposes, features and advantages of the present application, the specific implementation methods of the present application are described in detail in this section in conjunction with the accompanying drawings. In addition to the various implementation methods described in this section, the present application can also be implemented in other different ways. Without violating the spirit of the present application, those skilled in the art can make corresponding improvements, deformations and substitutions, so the present application is not limited by the specific embodiments disclosed in this section. The scope of protection of the present application shall be subject to the claims.

[0053] like Figures 2 to 4 As shown, the present application proposes a thrombus removal 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, the end of the bracket 1 close to the handle 4 (operator) is referred to as the proximal end of the bracket 1 ( Figure 2 The end of the bracket 1 away from the handle 4 (operator) is called the distal end of the bracket 1 ( Figure 2 left end of the ).

[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 may be in a hollow cylindrical shape. The sleeve 3 is sleeved on the core wire 2 . The sleeve 3 may slide along the front-rear direction X relative to the core wire 2 .

[0058] Furthermore, the sleeve 3 can be woven from metal wires, or made from metal tubes, or can be made from a combination of metal wires and metal tubes. The metal tube can be cut (e.g., laser cut) along the axial direction of the tube wall to form a spiral structure, and this spiral structure can adjust the hardness of the metal tube, so that the sleeve 3 has better bending resistance. The pitch of the spiral structure can be different at different parts of the sleeve 3, so that the corresponding sections of the sleeve 3 have appropriate hardness, for example, the proximal pitch of the sleeve 3 is smaller, and the distal pitch of the sleeve 3 is larger.

[0059] Generally, the hardness of the distal end of the sleeve 3 is less than that of the proximal end of the sleeve 3. The distal end of the sleeve 3 is relatively soft and easy to move in the blood vessel, while the proximal end of the sleeve 3 is relatively hard and easy to transmit the pushing force. The distal end of the sleeve 3 (the part close to the stent 1) uses a relatively soft structure (such as a metal wire braid, 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 relatively hard structure (such as a metal tube without a spiral structure).

[0060] The handle 4 is provided with a button 5 that can slide relative to the handle 4 in the front-to-back direction X. By pushing and pulling the button 5 in the front-to-back direction X, the sleeve 3 can be driven to move in the front-to-back direction X, thereby causing the proximal end of the stent 1 to move in the front-to-back direction X. When the thrombectomy stent is used, the handle 4 is used 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 bracket 1 can remain unchanged.

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

[0063] The stent 1 may be a mesh structure formed by weaving or etching, etc. The stent 1 may be deformed by applying a force along the front-to-back direction X. When the two ends of the stent 1 are brought close together under the action of an external force, the stent 1 may expand to increase the diameter of the stent 1. The expanded stent 1 may be spindle-shaped with a thick middle and thin ends.

[0064] The distal end of the stent 1 is formed with a protection portion (also called a tip), which is bent relative to the sleeve 3. The protection portion can be made of a soft material, and is conducive to the stent 1 turning in the blood vessel to prevent the stent 1 from damaging the blood vessel. It can be understood that the protection portion can also be straight when not subject to external force, and does not have to be bent relative to the sleeve 3.

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

[0066] When the operating 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 shrinks.

[0067] The stent 1 may include multiple layers of sub-stents, and when the stent 1 expands or contracts, the multiple layers of sub-stents may expand or contract together. The multiple layers of sub-stents may stabilize the thrombus and the stent 1, and the thrombus is not likely to fall off.

[0068] Specifically, Figures 5 to 7As shown, the stent 1 includes an inner layer thrombus retrieval net 11 and an outer layer thrombus retrieval net 12. When not constrained by external forces, the radial dimension of the outer layer thrombus retrieval net 12 is larger than the radial dimension of the inner layer thrombus retrieval net 11 as a whole, and the outer layer thrombus retrieval net 12 is wrapped outside the inner layer thrombus retrieval net 11. The inner layer thrombus retrieval net 11 and the outer layer thrombus retrieval net 12 can be different types of thrombus retrieval nets. The inner layer thrombus retrieval net 11 can be an adjustable thrombus retrieval net. The inner layer thrombus retrieval net 11 can be woven, also known as a woven thrombus retrieval net. The outer layer thrombus retrieval net 12 can be a self-expanding thrombus retrieval net. The outer layer thrombus retrieval net 12 can be carved, also known as a carved thrombus retrieval net. Both the inner layer thrombus retrieval net 11 and the outer layer thrombus retrieval net 12 can be made of nickel-titanium alloy, which 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 layer thrombectomy net 11 is connected to the sleeve 3, and the distal end of the inner layer thrombectomy net 11 is connected to the core wire 2, and the core wire 2 can slide in the front-back direction relative to the sleeve 3. The operating button 5 pulls the core wire 2 toward the proximal end, so that the inner layer thrombectomy net 11 can expand to form a shape with thin ends and thick middle, so that the inner layer thrombectomy net 11 is embedded in the thrombus.

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

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

[0072] The inner layer thrombus removal net 11 can be deformed by applying a force in the front-back direction. When the two ends of the inner layer thrombus removal net 11 are close to each other under the action of external force, the inner layer thrombus removal net 11 can be expanded to increase the diameter of the inner layer thrombus removal net 11. The expanded inner layer thrombus removal net 11 can be spindle-shaped with a thick middle and thin ends. The inner layer thrombus removal net 11 can be elastic, and the expanded inner layer thrombus removal net 11 can have a tendency to return to its original shape under the action of elastic force.

[0073] Before use, the inner thrombus removal net 11 and the outer thrombus removal net 12 are both in a contracted state. When in use, the outer thrombus removal net 12 expands and embeds into the thrombus by virtue of the shape memory property of nickel-titanium alloy after being untied, and the inner thrombus removal net 11 expands and embeds into the thrombus in an adjustable manner through the core wire 2.

[0074] In a possible implementation, Figures 8 to 10 As shown, the bracket 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 the same type of thrombus retrieval nets, and both the inner thrombus retrieval net 11 and the outer thrombus retrieval net 12 can be woven adjustable thrombus retrieval nets.

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

[0076] In a possible implementation, Fig.11 and Fig.12 As 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 the inner layer thrombus removal net 11 and the outer layer thrombus removal net 12 are both connected to the sleeve 3 , and the distal end of the outer layer thrombus removal net 12 is connected to the core wire 2 .

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

[0079] Preferably, the support 1 may be made of a material that can be developed by a developing instrument, or the support 1 may include a developing material, for example, including a plurality of developing points, so that the support 1 can be observed by a developing instrument.

[0080] like Figures 2 to 4 As shown, during the operation, the stent 1 first passes through the thrombus 100, and then the button 5 is pushed forward to move the sleeve 3 forward, the stent 1 expands, and the thrombus 100 is fixed to the stent 1. The thrombus 100 is moved along the blood vessel toward the outside of the body, gradually approaching the opening of the guide catheter. Afterwards, the handle 4 is held to retract the thrombus removal stent as a whole, so that the thrombus 100 can be recovered through the guide catheter. Before the stent 1 and the thrombus 100 enter the guide catheter, the stent 1 is retracted to a certain extent to facilitate the stent 1 and the thrombus 100 to enter the guide catheter. The handle 4 remains stationary, that is, when the overall position of the thrombus removal stent remains unchanged, the button 5 is pulled backward, and the sleeve 3 is pulled backward for easy control. When the stent 1 is retracted, the distal end position of the stent 1 remains unchanged, and the proximal end of the stent 1 moves toward the guide catheter. The thrombus 100 is fixed stably with the stent 1, and the thrombus 100 is not easy to fall off. Even if it falls off, the thrombus 100 can be easily collected into the guide 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-back direction X, but the button can be configured to be rotatable relative to the handle 4, in which case the button can also be called a trigger. In this case, for example, when the button is rotated backward away from the stent 1 (or called pressed or pulled), the button drives the sleeve 3 to move backward (toward the proximal end), thereby shrinking the stent 1.

[0082] Although the present application is described in detail using the above-mentioned 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 modified embodiment without departing from the subject matter and scope of the present application as determined by the claims. Therefore, the description in this specification is for the purpose of illustration and does not have any restrictive meaning for the present application.

Claims

1. A thrombectomy stent for ischemic stroke, characterized in that: The thrombus removal stent comprises: A stent (1), wherein the stent (1) is a frame structure for fixing a 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 capable of sliding relative to the handle (4) in a front-to-back direction (X) or capable of rotating relative to the handle (4), the sleeve (3) being connected to the button (5), and the sleeve (3) being able to move in the front-to-back direction (X) by operating the button (5), thereby applying force to the bracket (1), wherein When the button (5) is pushed forward, the bracket (1) can expand. When the button (5) is pulled backward or flipped, the bracket (1) can be retracted.

2. The thrombectomy stent for ischemic stroke according to claim 1, characterized in that: When the thrombus removal bracket is used, the handle (4) is used for holding.

3. The thrombectomy stent for ischemic stroke according to claim 1, characterized in that: The sleeve (3) is tubular and is sleeved on the core wire (2).

4. The thrombectomy stent for ischemic stroke according to claim 1, characterized in that: 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).

5. The thrombectomy stent for ischemic stroke according to claim 1, characterized in that: The support (1) has multiple layers of sub-supports.

6. The thrombectomy stent for ischemic stroke according to claim 1, characterized in that: The handle (4) is provided with a scale mark, and the scale mark is located next to the button (5) and is used to mark the diameter of the bracket (1) when the button (5) is in different positions.

7. The thrombectomy stent for ischemic stroke according to claim 6, characterized in that: The button (5) is provided with a pointer, and the pointer points to the scale mark.

8. The thrombectomy stent for ischemic stroke according to claim 1, characterized in that: A protection portion is formed at the distal end of the stent (1), and the protection portion is bent relative to the sleeve (3).

9. The thrombectomy stent for ischemic stroke according to claim 1, characterized in that: The hardness of the distal end portion of the sleeve (3) is smaller than the hardness of the proximal end portion of the sleeve (3).

10. The thrombectomy stent for ischemic stroke according to claim 1, characterized in that: The support (1) is a mesh structure formed by weaving or etching.

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