A thrombectomy stent and thrombectomy system

Abstract

The application provides a thrombus extraction stent and a thrombus extraction system, and belongs to the technical field of medical devices; wherein the thrombus extraction stent comprises a stent body formed by a filament member and having a mesh structure, the stent body has a compressed state and an expanded state, and the filament member is integrally arranged with fiber filaments, the density and / or length of the fiber filaments gradually increase from the proximal end to the distal end in the extending direction; and the application is mainly used to solve the technical problems of the insufficient thrombus capturing force of the existing thrombus extraction device, and the thrombus slipping or fragmentation to cause embolism.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology, specifically relating to a thrombectomy stent and thrombectomy system. Background Technology

[0002] Acute ischemic stroke (AIS) and other occlusive vascular diseases are among the leading causes of death and disability. Mechanical thrombectomy has become the standard treatment for large vessel occlusion, which involves delivering a thrombectomy device to the thrombus site via a microcatheter to capture and remove the thrombus to restore blood flow.

[0003] Currently, mainstream thrombectomy devices, such as stent-type thrombectomy devices, typically employ a self-expanding mesh structure made of woven metal wires. This device is constrained into a slender shape when passing through a microcatheter, and upon release, it self-expands to its pre-set shape at the thrombus site. The mesh structure embeds itself within the thrombus, and during retraction, the mechanical friction between the metal mesh and the thrombus pulls the thrombus into the guiding catheter, thereby achieving vascular recanalization.

[0004] However, existing thrombectomy devices have the following problems: First, the smooth surface of the metal wire has a limited coefficient of friction with the thrombus, making it difficult for the mesh structure to form an effective mechanical interlock. When the device is withdrawn through a bend in the blood vessel or into the catheter, the thrombus easily slips out of the mesh, leading to thrombectomy failure or requiring multiple procedures, prolonging the operation time and increasing the risk. Second, the pure metal mesh structure is difficult to fully embed within the thrombus. During device withdrawal, the device primarily exerts a pulling force on the thrombus as a whole, easily tearing large thrombi into fragments. These fragments escape with the bloodstream to distal sites, causing catastrophic distal or peripheral embolism, thus worsening the condition. This is one of the most significant safety risks in current thrombectomy procedures.

[0005] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Summary of the Invention

[0006] The purpose of this invention is to provide a thrombectomy stent and thrombectomy system to solve the technical problems of insufficient thrombus capture force of existing thrombectomy devices, which easily lead to thrombus slippage or fragmentation and embolism.

[0007] To achieve the above objectives, the thrombectomy stent of the present invention provides the following technical solution: A thrombectomy stent includes a stent body formed of filamentous components and having a mesh structure. The stent body has a compressed state and an expanded state. The filamentous components are integrated with fiber filaments, and the density and / or length of the fiber filaments gradually increase from the proximal end to the distal end.

[0008] As a further optimized technical solution, one end of the fiber is fixedly connected to the filamentous component, while the other end extends freely, and the fiber between the two ends is spiral or corrugated.

[0009] As a further optimized technical solution, at least a portion of the fibers are configured such that their free ends are inclined toward the proximal end of the scaffold body.

[0010] As a further optimized technical solution, at least a portion of the fiber filaments include a main fiber and a cilia structure extending from the surface of the main fiber.

[0011] As a further optimized technical solution, the fiber filament is coated with at least one agent, which includes one or more of anticoagulants, antiplatelet agents, or thrombolytic agents.

[0012] As a further optimized technical solution, the support body is provided with intercepting wires at intervals along the vertical axial direction. Both ends of the intercepting wires are fixedly connected to the filamentous components. The length of the intercepting wires is not less than the chordal dimension of the support body after expansion corresponding to the position of the intercepting wire.

[0013] As a further optimized technical solution, the proximal end of the stent body has a first developing component and / or the distal end has a plurality of circumferentially arranged second developing components.

[0014] As a further optimized technical solution, the mesh size of the support body gradually decreases from the proximal end to the distal end.

[0015] As a further optimized technical solution, the distal end of the stent body is a micro-flare structure that expands outward, so that the radial dimension of the distal end of the stent body in the expanded state is larger than the radial dimension of other positions.

[0016] To achieve the above objectives, the thrombectomy system of the present invention provides the following technical solution: A thrombectomy system, comprising: The thrombectomy stent according to any one of the above technical solutions; The feed wire is provided, and the bolt-retrieval bracket is located at the distal end of the feed wire. A microcatheter is used to deliver the compressed stent body to a target location within a blood vessel.

[0017] Beneficial effects: The thrombectomy stent of the present invention, through the density and / or length gradient design of the fiber filaments, significantly increases the contact area and mechanical interlocking force between the stent body and the thrombus, effectively preventing thrombus slippage; at the same time, the fiber filaments can evenly and gently disperse the pull-back stress, avoiding concentrated pulling on the local area of ​​the thrombus, thereby effectively preventing large thrombi from being torn apart, and significantly reducing the risk of distal embolism, the most serious surgical complication.

[0018] The beneficial effects of the thrombectomy system are similar to those of the thrombectomy stent, and will not be repeated here. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Wherein: Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of the thrombectomy system of the present invention; Figure 2 This is an enlarged structural diagram of some of the filamentous components in Embodiment 1 of the thrombectomy system of the present invention; Figure 3 This is a schematic diagram of the thrombectomy process in Embodiment 1 of the thrombectomy system of the present invention; Figure 4 This is a schematic cross-sectional view of the support body of Embodiment 2 of the thrombectomy system of the present invention.

[0020] In the diagram: 1. Stent body; 11. Filament component; 12. Fiber filament; 13. Interceptor wire; 2. First imaging component; 3. Second imaging component; 4. Microcatheter; 5. Delivery wire; 6. Blood vessel; 7. Thrombus. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0022] In the description of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. The terms "connected" and "linked" used in this invention should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; they can refer to a direct connection or an indirect connection through intermediate components. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0023] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0024] The shapes and sizes of the components in the accompanying drawings do not reflect the actual proportions of the product; they are only intended to illustrate the content of the invention.

[0025] Example 1 of the thrombectomy system like Figure 1 As shown, the thrombectomy system of this embodiment includes a thrombectomy stent, a delivery wire 5, and a microcatheter 4. The thrombectomy stent is fixedly disposed at the distal end of the delivery wire 5 (e.g., by adhesive bonding or welding). The physician can adjust the position and orientation of the thrombectomy stent by manipulating the delivery wire 5. The microcatheter 4 is used to accommodate the compressed thrombectomy stent and deliver it to the target thrombus 7 within the blood vessel 6. After the thrombectomy stent reaches the position, the stent body 1 is released and expanded by retracting the microcatheter 4, embedding itself inside the thrombus 7 to achieve capture. Finally, the stent capturing the thrombus 7 is removed from the body by retracting the delivery wire 5.

[0026] The stent body 1 of the thrombectomy stent is woven from nickel-titanium alloy filaments 11 to form a mesh structure. The nickel-titanium alloy material has good shape memory effect and biocompatibility, which can ensure that the stent can stably recover its expanded shape after compression. In the compressed state, the stent body 1 is adapted to the inner diameter of the microcatheter 4, which is convenient for delivery to the thrombus 7 through the blood vessel 6. In the expanded state, it can conform to the inner wall of the blood vessel 6 and embed itself inside the thrombus 7 to achieve capture.

[0027] like Figure 1 , Figure 2 As shown, all filamentous components 11 are integrated with fiber filaments 12, and the density and / or length of the fiber filaments 12 gradually increase from the proximal end to the distal end of the stent body 1: the proximal fiber filaments 12 have a lower density and shorter length, which can reduce friction and stimulation to the proximal vessel wall 6, and at the same time reduce the resistance during retraction; the distal fiber filaments 12 have a higher density and longer length, which can be more densely embedded in the distal thrombus 7, forming a stronger mechanical winding force, and preventing thrombus 7 fragments from slipping off from the distal end.

[0028] Furthermore, to enhance the interlocking effect between the fiber filament 12 and the thrombus 7, one end of the fiber filament 12 is fixedly connected to the filament component 11 (e.g., by laser welding, hot melt bonding, or integral molding process), while the other end extends freely. The fiber filament 12 between the two ends has a spiral or corrugated structure. Compared to the straight fiber filament 12, the spiral or corrugated structure can increase the contact area with the thrombus 7. At the same time, the structural elasticity enhances the wrapping effect on the thrombus 7. Even if the thrombus 7 has an irregular shape, it can still achieve a tight fit through the deformation of the fiber filament 12.

[0029] Furthermore, at least some of the free ends of the fiber filaments 12 are inclined toward the proximal end of the stent body 1. This design allows the free ends of the fiber filaments 12 to "hook" onto the internal structure of the thrombus 7 when the stent expands and embeds into the thrombus 7. When the thrombectomy stent is withdrawn, the inclination direction is consistent with the withdrawal direction, which can further enhance the drag force on the thrombus 7 and prevent the thrombus 7 from slipping off the fiber filaments 12.

[0030] To further enhance the ability to lock onto the thrombus 7, at least a portion of the filaments 12 include a main fiber and a ciliary structure extending from the surface of the main fiber. The cilia can penetrate deep into the tiny pores of the thrombus 7, forming a "microscopic interlock," which significantly increases the friction between the filaments 12 and the thrombus 7, while reducing the risk of thrombus 7 fragmentation during capture. Even if there are minor breaks on the surface of the thrombus 7, the villous structure can still adsorb small thrombus 7 particles, preventing distal embolism.

[0031] To meet the anticoagulation and thrombolysis requirements during thrombectomy, the fiber filament 12 is coated with at least one agent, including one or more of anticoagulants (such as heparin and warfarin), antiplatelet agents (such as aspirin and clopidogrel), or thrombolytic agents (such as urokinase and alteplase). The agent can be attached to the surface of the fiber filament 12 using a sustained-release coating technology and slowly released after the stent body 1 expands. This prevents the formation of new thrombi 7 in the blood vessel 6 during thrombectomy and allows for preliminary thrombolysis of the captured thrombi 7, reducing their hardness and facilitating greater embedding of the stent body within the thrombi 7, thereby enhancing the gripping force on the thrombi 7.

[0032] To meet the positioning requirements of the stent during surgery, the stent body 1 has a first imaging component 2 at its proximal end and / or multiple circumferentially arranged second imaging components 3 at its distal end. The first imaging component 2 helps the doctor confirm the position of the proximal end of the stent, avoiding excessive insertion of the stent into the blood vessel 6; the multiple circumferentially arranged second imaging components 3 can clearly show the expansion state of the distal end of the stent and the coverage area of ​​the thrombus 7, ensuring that the stent completely covers the thrombus 7. The imaging components can be made of high-density metal materials such as tungsten or platinum-iridium alloy, and are fixed to the stent body 1 by inlay or welding.

[0033] Furthermore, the mesh size of the stent body 1 gradually decreases from the proximal end to the distal end. As a result, the proximal end of the stent body 1 has a larger mesh size, making it easier to compress. This allows the stent body 1 to be easily compressed and recycled into the microcatheter 4 later, facilitating its recovery.

[0034] To further improve the sealing of thrombus 7 capture, the distal end of the stent body 1 features an outwardly expanding micro-flare structure, making the radial dimension of the distal end of the expanded stent body 1 larger than that of other locations. In this way, after thrombus 7 is embedded on one side of the stent body 1, the micro-flare structure can form a blocking structure at the distal end of the stent body 1 for the portion of thrombus 7 not embedded in the stent body 1. This allows the micro-flare structure to fit more tightly against the distal inner wall of the vessel 6, preventing thrombus 7 on the outside of the stent body 1 from slipping out of the gap between the stent body 1 and the vessel 6 wall.

[0035] like Figure 3 As shown, the usage process of the thrombectomy system in this embodiment is as follows: First, the distal end of the microcatheter 4 is delivered to the vicinity of the thrombus 7 in the blood vessel 6 through the blood vessel 6 access. The first imaging component 2 and the second imaging component 3 are observed by imaging equipment to confirm that the distal end of the stent body 1 extends beyond the distal end of the thrombus 7. Then, keeping the delivery wire 5 in place, slowly retract the microcatheter 4, so that the stent body 1 is released from the microcatheter 4 and automatically expands. The mesh structure of the stent body 1 is embedded inside the thrombus 7, the spiral structure of the fiber filament 12 and the nanofibers wrap around the thrombus 7, and the distal microflare structure adheres to the distal inner wall of the blood vessel 6, forming a stop structure to prevent the thrombus 7 from escaping to the distal end. After the stent body 1 expands, the delivery wire 5 is slowly retracted, causing the stent body 1 and the captured thrombus 7 to move together; the stent body 1 and the thrombus 7 are pulled into the microcatheter 4, and then the microcatheter 4 and the delivery wire 5 are withdrawn from the body together to complete the thrombus removal operation.

[0036] Example 2 of the thrombectomy system like Figure 4 As shown, the difference between this embodiment and Embodiment 1 lies in the internal structure of the stent body 1. All other structures are identical to those in Embodiment 1. In this embodiment, intercepting wires 13 are spaced apart along the vertical axial direction on the stent body 1. The intercepting wires 13 are made of the same material as the fiber filaments 12. Both ends of the intercepting wires 13 are fixedly connected to different filamentous components 11, forming a thrombus 7 interception structure inside the stent body 1. This allows the thrombus 7 embedded inside the stent body 1 to be further intercepted laterally, effectively ensuring the strong bond between the thrombus 7 and the stent body 1. Furthermore, to prevent the intercepting wires 13 from hindering the normal expansion of the stent body 1, the length of the intercepting wires 13 is not less than the chordal dimension of the corresponding intercepting wire 13 position after the stent body 1 has expanded.

[0037] An embodiment of the thrombectomy stent of the present invention: The structure of the thrombectomy stent in this embodiment is the same as that in the thrombectomy system embodiment described above, and will not be repeated here.

[0038] In summary, the thrombectomy stent and thrombectomy system provided by this invention effectively solve the problems of thrombus slippage and fragmentation in existing thrombectomy devices through structural innovation and functional integration. It has both high capture power and high safety, and can be widely used in mechanical thrombectomy treatment of diseases such as acute ischemic stroke and peripheral vascular occlusion.

[0039] It is understood that the above description is merely exemplary and the embodiments of this application do not limit the scope of the application.

[0040] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are within the protection scope of the present invention.

Claims

1. A thrombectomy stent, characterized in that, The support body (1) is formed by filamentous components (11) and has a mesh structure. The support body (1) has a compressed state and an expanded state. Fiber filaments (12) are integrated on the filamentous components (11). The density and / or length of the fiber filaments (12) gradually increase from the proximal end to the distal end.

2. The thrombectomy bracket according to claim 1, characterized in that, One end of the fiber filament (12) is fixedly connected to the filamentous component (11), and the other end extends freely. The fiber filament (12) between the two ends is spiral or corrugated.

3. The thrombectomy bracket according to claim 2, characterized in that, At least a portion of the fiber filaments (12) are configured such that their free ends are inclined toward the proximal end of the support body (1).

4. The thrombectomy bracket according to claim 1, characterized in that, At least a portion of the fiber filaments (12) include a trunk fiber and a cilia structure extending from the surface of the trunk fiber.

5. The thrombectomy bracket according to claim 1, characterized in that, The fiber filament (12) is coated with at least one agent, which includes one or more of an anticoagulant, an antiplatelet agent, or a thrombolytic agent.

6. The thrombectomy bracket according to claim 1, characterized in that, The support body (1) is provided with intercepting wires (13) spaced apart along the vertical axial direction. Both ends of the intercepting wires (13) are fixedly connected to the filamentous component (11). The length of the intercepting wires (13) is not less than the chord dimension of the support body (1) after expansion corresponding to the position of the intercepting wires (13).

7. The thrombectomy stent according to any one of claims 1-6, characterized in that, The support body (1) has a first developing component (2) at its proximal end and / or a plurality of circumferentially arranged second developing components (3) at its distal end.

8. The thrombectomy stent according to any one of claims 1-6, characterized in that, The mesh size of the support body (1) gradually decreases from the proximal end to the distal end.

9. The thrombectomy stent according to any one of claims 1-6, characterized in that, The distal end of the stent body (1) is a micro-flare structure that expands outward, so that the radial dimension of the distal end of the stent body (1) in the expanded state is greater than the radial dimension of other positions.

10. A thrombus removal system, characterized in that, include: The thrombectomy stent according to any one of claims 1-9; The conveyor wire (5) is provided with the bolt-taking bracket located at the far end of the conveyor wire (5). Microcatheter (4) is used to deliver the compressed stent body (1) to the target location within the blood vessel (6).

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