Double-layer thrombus extraction stent

Abstract

The invention belongs to the field of medical instruments, particularly relates to a double-layer thrombus extraction stent, and provides the following scheme aiming at the problems that an existing thrombus extraction stent is large in damage to blood vessels, thrombus remains and poor in adaptability, a main body of the double-layer thrombus extraction stent is made of a nickel-titanium alloy material, and the double-layer thrombus extraction stent comprises a handle, a double-layer mesh cage stent, a core wire, a conical flexible head and a catheter. The head is of a conical flexible structure, and friction damage to the blood vessel wall is reduced. According to the inner-layer and outer-layer mesh cage support, outer-layer large meshes capture large thrombus, inner-layer small meshes capture small-particle thrombus, and the removing efficiency is improved. The puller is exquisite in design, a doctor presses a button and pushes a push block to control the support to unfold and contract, and scale marks of a handle assist in accurate operation. The nickel-titanium alloy enables the stent to adapt to vascular expansion, and the stent has a temperature control memory function. The thrombus extraction stent improves operation safety, thrombus removal efficiency and treatment success rate, can be accurately controlled and adapted to different blood vessels, and reduces complications and thrombus residual risks.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a double-layer thrombectomy stent. Background Technology

[0002] Thrombosis, as the primary culprit behind a series of acute vascular diseases such as stroke, myocardial infarction, and pulmonary embolism, poses a significant potential danger. When a thrombus silently forms and accumulates within a blood vessel, it acts like a series of roadblocks on a vital artery, relentlessly obstructing the blood flow and instantly cutting off normal blood supply. Once blood perfusion to vital organs is interrupted, cells rapidly damage due to hypoxia and nutrient deficiency, leading to a series of serious and irreversible medical consequences. These can range from mild decline in bodily functions and impaired quality of life to life-threatening conditions, inflicting a heavy blow on patients and their families. In the current medical technology system, thrombolysis and mechanical thrombectomy are the two main treatment methods for thrombosis. Thrombolysis, with its unique pharmacological effects, can dissolve thrombi to a certain extent and restore vascular patency. However, this method is not without its limitations. Its application window is extremely narrow, like searching for a fleeting door of hope in the dark; medication must be administered within a specific timeframe after thrombus formation to achieve optimal efficacy. If this critical period is missed, the thrombolytic effect of the drug will be greatly reduced, or even rendered ineffective. More problematic is the risk of bleeding side effects associated with thrombolysis. During the process of dissolving blood clots, the drug may interfere with the normal clotting mechanism of the blood vessel wall, leading to an increased tendency to bleed and potentially causing serious complications such as intracranial hemorrhage and gastrointestinal bleeding, further threatening the patient's life.

[0003] In contrast, mechanical thrombectomy, as a more direct physical treatment method, demonstrates unique advantages. Especially in challenging situations involving large-area thrombi or unresponsive drug therapy, it acts like a precise "vascular scavenger," quickly and effectively removing thrombi and restoring blood flow. By precisely delivering a thrombectomy stent to the thrombus site, deploying the stent to capture the thrombus, and then safely removing the thrombus from the blood vessel using a catheter, mechanical thrombectomy offers patients new hope for treatment.

[0004] However, the thrombectomy stents widely used in the market are not without flaws, and a series of technical problems that urgently need to be solved have been exposed in actual use.

[0005] 1. Most existing thrombectomy stents employ a mesh-like structure design. While this design helps capture thrombi to some extent, it harbors significant risks during deployment within the blood vessel. The blood vessel wall itself is quite fragile, especially when facing small vessels, where its tolerance is even more limited, as exemplified by the thrombectomy stent in patent document CN201811338404.6. As the stent gradually deploys within the vessel, attempting to cover and capture the thrombus, its rigid mesh structure easily rubs and collides with the vessel wall, much like a rough brush scraping soft silk, inevitably causing damage. This damage can lead to vessel rupture, bleeding, and even serious problems such as vasospasm, further aggravating the patient's condition and increasing the complexity and risk of treatment. Especially in areas with tortuous or narrow blood vessels, stent deployment is more difficult, and the risk of damage to the vessel wall is higher, posing a significant challenge to the surgical procedure.

[0006] 2. While existing thrombectomy stents have shown some effectiveness in capturing large thrombi, rapidly removing them, they fall short when dealing with small, granular thrombi. These small thrombi act like cunning thieves, easily slipping through the stent's mesh and escaping throughout the blood vessel, leading to thrombus residue. This residue may re-aggregate with blood flow, forming new thrombi and causing further thrombus formation and re-blockage of the vessel, significantly reducing treatment effectiveness. For example, patent document CN202211662064.9 describes a double-layered thrombectomy stent and system. Furthermore, the composition and properties of thrombi are complex and diverse; some thrombi are loosely structured and easily break into small particles, further increasing the difficulty of capturing thrombi with existing stents and reducing the success rate and reliability of treatment.

[0007] 3. The human vascular system is like a complex maze, with various bends, bifurcations, and narrowings. However, existing thrombectomy stents are too rigid, lacking sufficient flexibility and adaptability. Like a ruler struggling to pass through a curved pipe, they are cumbersome when faced with complex vascular anatomy. When a stent attempts to pass through a bend in the blood vessel, its rigid structure creates significant resistance against the vessel wall, making it difficult to advance smoothly, and it may even become stuck in the vessel, unable to reach the thrombus. This not only increases the complexity and risk of the procedure and prolongs the operation time, but may also cause further damage to the blood vessel. Furthermore, at vascular bifurcations, existing stents are difficult to accurately locate and deploy, failing to effectively capture the thrombus, thus affecting the treatment's effectiveness and safety.

[0008] Therefore, there is an urgent need for a well-designed, safe, efficient, and adaptable thrombectomy stent to address the shortcomings of existing technologies. Summary of the Invention

[0009] The purpose of this invention is to address the following issues in existing technologies: 1. Most existing thrombectomy stents employ a mesh-like structure design. While this design helps capture thrombi to some extent, it also harbors significant risks during deployment within the blood vessel. The blood vessel wall itself is very fragile, especially when facing small vessels, where its tolerance is even more limited. As the stent gradually deploys within the blood vessel, attempting to cover and capture the thrombus, its rigid mesh structure easily rubs and collides with the vessel wall, much like a rough brush scraping soft silk, inevitably causing damage to the vessel wall. This damage can lead to vessel wall rupture, bleeding, and even serious problems such as vasospasm, further aggravating the patient's condition and increasing the complexity and risk of treatment. Especially in areas where blood vessels are more tortuous or narrow, stent deployment is more difficult, and the risk of damage to the vessel wall is higher, posing a significant challenge to the surgical procedure.

[0010] 2. While existing thrombectomy stents have shown some effectiveness in capturing large thrombi, rapidly removing them, they fall short when dealing with small, granular thrombi. These small thrombi act like cunning thieves, easily slipping through the stent's mesh and escaping throughout the blood vessel, leading to thrombus residue. This residue can re-aggregate with blood flow, forming new thrombi and causing further thrombus reformation and re-blockage of the vessel, significantly reducing treatment effectiveness. Furthermore, the complex and diverse composition and properties of thrombi, with some being loosely structured and easily breaking into small particles, further increases the difficulty of capturing thrombi with existing stents, reducing treatment success rates and reliability.

[0011] 3. The human vascular system is like a complex maze, with various bends, bifurcations, and narrowings. However, existing thrombectomy stents are too rigid, lacking sufficient flexibility and adaptability. Like a ruler struggling to pass through a curved pipe, they are cumbersome when faced with complex vascular anatomy. When the stent attempts to pass through a bend in the blood vessel, its rigid structure creates significant resistance against the vessel wall, making it difficult to advance smoothly, and it may even become stuck in the vessel, unable to reach the thrombus. This not only increases the complexity and risk of the procedure and prolongs the operation time, but may also cause further damage to the blood vessel. Furthermore, at vascular bifurcations, existing stents are difficult to accurately locate and deploy, failing to effectively capture the thrombus, affecting the treatment's effectiveness and safety. Therefore, a double-layered thrombectomy stent is proposed.

[0012] To achieve the above objectives, the present invention adopts the following technical solution:

[0013] A double-layer thrombectomy stent includes a main body made of nickel-titanium alloy. The main body includes a handle, a first mesh cage support, a second mesh cage support, a core wire, a head with a tapered flexible structure, and a catheter. One end of the catheter is fixedly connected to one end of the handle. One end of the first mesh cage support and one end of the second mesh cage support are both fixedly connected to one end of the core wire, and the other end is fixedly connected to one end of the head. The second mesh cage support is located inside the first mesh cage support, and the core wire is located inside the catheter and is slidably connected.

[0014] To facilitate the unfolding and retraction of the first and second mesh cage supports, a puller is also included, which can be used to pull the first and second mesh cage supports to unfold and retract.

[0015] Preferably, the puller includes a push block, a button, a spring, and a movable plate, and the top of the handle has a groove, with the bottom of the push block slidably connected to the bottom inner wall of the groove.

[0016] Preferably, the push block has a receiving groove, the outer side of the button is slidably connected to the inner wall of the receiving groove, one side of the push block has a through hole, one side of the movable plate is fixedly connected to one side of the button, and the movable plate is located in the through hole.

[0017] Preferably, the bottom end of the spring is fixedly connected to the bottom inner wall of the receiving groove, and the top end is fixedly connected to the bottom of the button. A round hole is provided on one side of the handle, and one end of the core wire passes through the round hole and is fixedly connected to one side of the push block.

[0018] Preferably, the puller further includes a post and multiple insertion holes. The bottom end of the post is fixedly connected to the top of the movable plate. A movable groove is provided on one side of the inner wall of the groove. One end of the movable plate is located in the movable groove. The width of the movable groove is the same as the width of the through hole. Multiple insertion holes are provided on the top inner wall of the movable groove. The top end of the post is inserted into the insertion hole.

[0019] Preferably, the top of the handle has a scale line for marking.

[0020] Preferably, the mesh size of the first wire mesh cage support is larger than that of the second wire mesh cage support.

[0021] Preferably, the mesh openings of the first wire mesh cage support are hexagonal, and the mesh openings of the second wire mesh cage support are irregular polygons.

[0022] The beneficial effects of this invention are as follows:

[0023] 1. The main body of the thrombectomy stent is made of nickel-titanium alloy, a material with excellent biocompatibility and superelasticity, allowing the stent to self-deploy within the blood vessel and adhere closely to the vessel wall without causing excessive irritation. Nickel-titanium alloy also has a temperature-controlled memory function, ensuring stable deployment and retrieval of the stent under different temperature conditions.

[0024] 2. The head is made of flexible material and has a conical structure. During the process of the stent being delivered to the thrombus site through the blood vessel, this design allows it to better adapt to the curvature and changes of the blood vessel, easily pass through complex blood vessel paths, significantly reduce friction and collision with the blood vessel wall, effectively avoid damage to the blood vessel wall caused by the rigid structure of the stent, and reduce the risk of serious complications such as blood vessel wall rupture, bleeding and vasospasm. The advantages are more obvious when facing more tortuous and narrow blood vessels, which greatly improves the safety of the operation.

[0025] 3. Employing a unique double-layer mesh design, the outer first mesh cage has larger, hexagonal mesh openings, enabling rapid capture of larger thrombus fragments. The inner second mesh cage has smaller, irregularly shaped polygonal mesh openings, allowing it to capture small, granular thrombi. This design ensures the stent can simultaneously capture thrombi of varying sizes, avoiding the risk of thrombus residue, significantly improving thrombus removal efficiency, reducing the possibility of thrombus reformation and re-blockage due to thrombus residue, and enhancing treatment success rate and reliability. The interlocking inner mesh openings act like multiple small stents working together to pull the thrombus, further enhancing the ability to capture small thrombi and effectively preventing their escape, providing a strong guarantee for complete thrombus removal.

[0026] 4. The equipped puller has a sophisticated structure and is easy to operate. The surgeon presses a button with their finger, compressing the spring and disengaging the insert at the top of the movable plate from the insertion hole. Then, the pusher slides within the groove, causing the core wire to slide within the catheter, thus enabling the deployment and retraction of the first and second mesh cage supports. This design allows the surgeon to precisely control the deployment degree and position of the supports during surgery, making flexible adjustments according to the actual situation, improving the precision and efficiency of the operation. The graduations on the top of the handle provide the surgeon with a visual reference, allowing them to understand the degree of support deployment and better control the force and scale of operation, further improving the controllability of the surgery. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the front view of a double-layer thrombectomy support proposed in this invention;

[0028] Figure 2 This is a front view schematic diagram of a double-layer thrombectomy stent proposed in this invention;

[0029] Figure 3This is a side view of the handle structure of a double-layer thrombectomy bracket proposed in this invention;

[0030] Figure 4 This is a cross-sectional view of the handle structure of a double-layer thrombectomy bracket proposed in this invention.

[0031] In the diagram: 1. Main body; 2. Handle; 3. Guide tube; 4. Core wire; 5. First cage support; 6. Second cage support; 7. Head; 8. Push block; 9. Scale line; 10. Groove; 11. Moving groove; 12. Button; 13. Receiving groove; 14. Movable plate; 15. Through hole; 16. Insert post; 17. Spring. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0033] Example 1

[0034] Reference Figure 1-4 A double-layer thrombectomy stent, used in the field of medical devices, comprises a main body 1 made of nickel-titanium alloy. The main body 1 integrates several key components such as a handle 2, a first mesh cage support 5, a second mesh cage support 6, a core wire 4, a head with a conical flexible structure 7, and a catheter 3. The components work together to achieve efficient and safe thrombectomy.

[0035] The catheter 3 is made of medical material with a certain degree of flexibility and strength, and one end is securely connected to the handle 2. The handle 2 provides a grip for the doctor's operation, and its shape is ergonomically designed to facilitate stable gripping and precise operation.

[0036] The cage support, core wire 4, and head 7: Both the first cage support 5 and the second cage support 6 are woven from nickel-titanium alloy wire, possessing good elasticity and flexibility. One end of the first cage support 5 and one end of the second cage support 6 are tightly and fixedly connected to one end of the core wire 4, while the other end is reliably connected to one end of the head 7. The second cage support 6 is cleverly positioned inside the first cage support 5, forming a double-layer structure. The core wire 4 is located inside the guide tube 3 and can slide smoothly within the guide tube 3; this sliding connection provides the basis for the expansion and contraction of the cage support.

[0037] The head 7 is made of flexible material and designed with a conical structure. This unique structure allows the head 7 to move like a flexible cone when propelled through blood vessels, easily adapting to the bends and changes in the vessels, effectively reducing friction and collision with the vessel walls, and lowering the risk of damage to the vessel walls.

[0038] To facilitate precise deployment and retraction of the first mesh cage support 5 and the second mesh cage support 6 by doctors, this thrombectomy stent is equipped with a special puller.

[0039] The puller mainly consists of a push block 8, a button 12, a spring 17, and a movable plate 14. A groove 10 is provided at the top of the handle 2, and the push block 8 is placed within the groove 10, with its bottom slidably connected to the inner wall of the groove 10. A receiving groove 13 is provided on the push block 8, and the outer side of the button 12 is tightly slidably connected to the inner wall of the receiving groove 13, ensuring that the button 12 can move stably up and down within the receiving groove 13. A through hole 15 is provided on one side of the push block 8, and one side of the movable plate 14 is fixedly connected to one side of the button 12, with the movable plate 14 located within the through hole 15, allowing it to move synchronously with the movement of the button 12. The bottom end of the spring 17 is firmly fixedly connected to the inner wall of the receiving groove 13, and the top end is fixedly connected to the bottom of the button 12, providing elastic force for the button 12 to reset. A circular hole is provided on one side of the handle 2, and one end of the core wire 4 passes through this hole and is fixedly connected to one side of the push block 8, thereby enabling the core wire 4 to slide within the guide tube 3 by the movement of the push block 8.

[0040] Operation of the puller: When the doctor needs to perform thrombectomy, first press button 12 with your finger. Button 12 moves downward under pressure, simultaneously compressing spring 17. As button 12 moves, the movable plate 14, which is fixedly connected to it, also moves downward, causing the insertion post 16 at the top of the movable plate 14 to leave the insertion hole (the structure of insertion post 16 and insertion hole will be described in detail later). At this time, the doctor can push the push block 8 to slide in the groove 10. The movement of the push block 8 causes the core wire 4 to slide in the catheter 3, thereby causing the first mesh cage support 5 and the second mesh cage support 6 to gradually leave the inside of the catheter 3, realizing the unfolding action. After the thrombectomy is completed, the doctor releases button 12. Spring 17 returns to its original state under elastic force, pushing button 12 upward, causing the movable plate 14 and insertion post 16 to reset. At the same time, the push block 8 and core wire 4 pull the first mesh cage support 5 and the second mesh cage support 6 back into the catheter 3, completing the retraction operation.

[0041] The puller also includes a pin 16 and multiple insertion holes. The bottom end of the pin 16 is fixedly connected to the top of the movable plate 14. A movable groove 11 is provided on one side of the inner wall of the groove 10. One end of the movable plate 14 is located inside the groove, and the width of the movable groove 11 is the same as the width of the through hole 15, ensuring that the movable plate 14 can move stably within the movable groove 11. Multiple insertion holes are provided on the top inner wall of the movable groove 11. When the doctor presses the button 12 to move the movable plate 14 to the appropriate position, the top end of the pin 16 can be accurately inserted into the insertion hole to fix the position of the push block 8, thereby fixing the unfolding degree of the first mesh cage support 5 and the second mesh cage support 6, facilitating subsequent operations by the doctor.

[0042] Example 2

[0043] refer to Figure 1-4 An improvement upon Embodiment 1 is made by adding marking lines 9 to the top of the handle 2. These marking lines 9 provide a visual reference for the surgeon, allowing them to understand the movement distance of the pusher 8 and thus accurately control the deployment degree of the first mesh cage support 5 and the second mesh cage support 6. During the procedure, the surgeon can flexibly adjust the deployment degree of the support based on the size and location of the thrombus, combined with the indications of the marking lines 9, ensuring accurate and effective thrombus capture and improving the precision and success rate of the surgery.

[0044] The mesh size of the first mesh cage support 5 is larger than that of the second mesh cage support 6. This design with different mesh sizes has unique advantages. During thrombectomy, the first mesh cage support 5 with larger mesh sizes can quickly capture larger thrombus clots, while the second mesh cage support 6 with smaller mesh sizes can capture small granular thrombi, preventing these tiny thrombi from escaping and ensuring thorough thrombus removal.

[0045] The first mesh cage support 5 has hexagonal mesh openings. This mesh structure is stable and provides a large opening area while ensuring the flexibility of the support, which is beneficial for the entry and capture of large thrombi. The second mesh cage support 6 has irregular polygonal mesh openings. This irregular shape makes the connection between the mesh openings tighter, which can better capture small granular thrombi and further improve the efficiency of thrombus capture.

[0046] When using the thrombectomy stent described in this application, the doctor carefully inserts a catheter into the patient's blood vessel (such as the femoral or radial artery). Under the guidance of imaging equipment (such as an X-ray machine), the catheter is slowly advanced, gradually moving it closer to the thrombus site along the blood vessel. During the advancement process, the doctor needs to closely observe the imaging to ensure that the catheter passes through the blood vessel smoothly and avoids damage to the blood vessel wall. Once the catheter reaches the appropriate position, the doctor slowly delivers the main body of the thrombectomy stent (including the first mesh cage stent, the second mesh cage stent, the core wire, and the head) to the thrombus site through the catheter. During delivery, it's crucial to maintain the stent's stability and prevent collisions or friction with the vessel wall. The head's cone-shaped flexible structure better adapts to the curves and changes in the blood vessel, reducing damage and helping the stent reach its target location smoothly. The doctor holds the handle with one hand and presses the button with their finger. The button moves downwards, compressing the spring and simultaneously causing the insert at the top of the movable plate to disengage from the insertion hole. This pusher then slides within the groove. As the pusher moves, it causes the mandrel to slide within the catheter. The movement of the mandrel causes the first and second mesh cage stents to leave the catheter and gradually unfold, encapsulating the thrombus. Because the mesh size of the first mesh cage stent is larger than that of the second mesh cage stent, and the first mesh cage stent has hexagonal mesh while the second mesh cage stent has irregular polygonal mesh, this design improves the efficiency of thrombus capture. The larger mesh size of the first mesh cage stent can quickly capture larger thrombus masses, while the smaller mesh size of the second mesh cage stent can capture smaller granular thrombi, reducing thrombus residue. After the stent is deployed, the doctor adjusts its angle and position using a handle to ensure all thrombi are captured within the stent. The stent is then slowly retracted, ensuring all thrombi are completely removed. The stent employs a double-layered mesh design. The outer layer with large mesh openings captures large thrombi, while the inner layer with smaller mesh openings ensures that even small thrombus particles do not escape, greatly improving thrombus removal efficiency. The interlocking inner layers act like thrombi pulling on individual stents, preventing small thrombi from escaping. The head is made of flexible material and designed with a conical structure, significantly reducing friction and damage to the vessel wall during stent deployment. This makes it particularly suitable for navigating complex vascular anatomy. The multi-layered mesh design ensures the stent can simultaneously capture thrombi of different sizes, avoiding the risk of thrombus residue and improving treatment outcomes. The flexible material and conical design significantly reduce damage to the vessel during stent deployment and removal, making it especially safer when operating in tortuous or narrow vessels.

[0047] The stent's high flexibility and controllable deployment design allow it to adapt to different types of blood vessels, including arteries and veins, making it more widely applicable. The main body is made of a nickel-titanium alloy with good biocompatibility and superelasticity. The first and second mesh cage stents of the main body are multi-segment elastic mesh structures with good flexibility, enabling them to deploy smoothly within blood vessels and adapt to blood vessels of different diameters.

[0048] The accompanying drawings in this application are for illustrative purposes only. The dimensions and shapes of the components shown are not actual limitations but are merely schematic representations. In actual implementation, the components can be reasonably configured and adjusted according to specific needs and actual conditions.

[0049] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A double-layer thrombectomy stent, characterized in that, The main body (1) is made of nickel-titanium alloy. The main body (1) includes a handle (2), a first wire cage support (5), a second wire cage support (6), a core wire (4), a head (7) with a conical flexible structure, and a guide tube (3). One end of the guide tube (3) is fixedly connected to one end of the handle (2). One end of the first wire cage support (5) and one end of the second wire cage support (6) are both fixedly connected to one end of the core wire (4), and the other end is fixedly connected to one end of the head (7). The second wire cage support (6) is located inside the first wire cage support (5). The core wire (4) is located inside the guide tube (2) and is slidably connected. To facilitate the unfolding and retraction of the first cage support (5) and the second cage support (6), a puller is also included, which can be used to pull the first cage support (5) and the second cage support (6) to unfold and retract.

2. The double-layer thrombectomy stent according to claim 1, characterized in that, The puller includes a push block (8), a button (12), a spring (17), and a movable plate (14). The top of the handle (2) has a groove (10). The bottom of the push block (8) is slidably connected to the inner wall of the bottom of the groove (10). The push block (8) has a receiving groove (13). The outer side of the button (12) is slidably connected to the inner wall of the receiving groove (13).

3. A double-layer thrombectomy stent according to claim 2, characterized in that, The push block (8) has a through hole (15) on one side, and the movable plate (14) is fixedly connected to the button (12) on one side. The movable plate (14) is located inside the through hole (15).

4. A double-layer thrombectomy stent according to claim 3, characterized in that, The bottom end of the spring (17) is fixedly connected to the bottom inner wall of the receiving groove (13), and the top end is fixedly connected to the bottom of the button (12). A round hole is provided on one side of the handle (2), and one end of the core wire (4) passes through the round hole and is fixedly connected to one side of the push block (8).

5. A double-layer thrombectomy stent according to claim 2, characterized in that, The puller also includes a pin (16) and multiple insertion holes. The bottom end of the pin (16) is fixedly connected to the top of the movable plate (14). A movable groove (11) is provided on one side inner wall of the groove (10). One end of the movable plate (14) is located in the movable groove (11). The width of the movable groove (11) is the same as the width of the through hole (15). Multiple insertion holes are provided on the top inner wall of the movable groove (11). The top end of the pin (16) is inserted into the insertion hole.

6. A double-layer thrombectomy stent according to claim 1, characterized in that, The top of the handle (2) is provided with scale lines (9) for marking.

7. A double-layer thrombectomy stent according to claim 1, characterized in that, The mesh size of the first wire mesh cage support (5) is larger than that of the second wire mesh cage support (6).

8. A double-layer thrombectomy stent according to claim 1, characterized in that, The mesh of the first cage support (5) is hexagonal, and the mesh of the second cage support (6) is an irregular polygon.

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