thrombectomy device

Abstract

This invention provides a thrombectomy device. It includes: an expandable and contractible net assembly and a delivery assembly; the net assembly includes at least one net unit; when the net assembly includes multiple net units, the multiple net units are arranged axially at intervals; each net unit includes: a net body and multiple pull rods; the net body has a flat net structure with a distally closed end, and the distal ends of the multiple pull rods are respectively connected to the proximal end of the net body; the distal end of the net unit is connected to the delivery assembly, and the proximal ends of the multiple pull rods of the net unit converge and connect to the delivery assembly, forming an opening between the multiple pull rods; the delivery assembly is used to receive the net assembly in a compressed state, and is capable of releasing the net assembly to an expanded state and pulling the expanded net assembly back into the catheter. Embodiments of this invention, using a net structure for thrombectomy, can improve the success rate of a single thrombectomy and effectively prevent thrombus escape during the thrombectomy process.

Description

Technical Field

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

[0002] Intravascular thrombosis is a systemic disease with a very wide range of effects, potentially affecting blood vessels in the upper and lower limbs, internal organs, and carotid arteries. When a thrombus occurs in the heart, it can cause a myocardial infarction; in the brain, it can cause a cerebral infarction; in the lungs, it can cause a pulmonary embolism… Statistics show that deaths caused by thrombotic diseases account for 51% of all deaths worldwide, far exceeding deaths caused by cancer, infectious diseases, and respiratory diseases.

[0003] Currently, the main treatments for thrombosis include anticoagulant therapy, interventional procedures, and surgery. For patients with mild symptoms, conservative treatment with anticoagulants is possible; however, for patients who cannot be treated with medication, surgery is necessary. Compared to surgery, interventional therapy is less invasive, has a faster recovery time, and is more readily accepted by patients. The effectiveness of interventional therapy is largely limited by the interventional devices used.

[0004] The inventors discovered that due to the diversity of thrombotic sites and the complexity of thrombus morphology, existing thrombectomy devices, such as thrombectomy stents and aspiration catheters, generally have the problems of difficulty in completely removing thrombi, low success rate of thrombectomy in a single attempt, and easy escape of fragmented thrombi that can block distal branches. Summary of the Invention

[0005] The purpose of this invention is to provide a thrombectomy device that solves the problems of low success rate of thrombectomy in one attempt and easy omission of fragmented thrombi.

[0006] To address the aforementioned technical problems, embodiments of the present invention provide a thrombus removal device, comprising:

[0007] An expandable and retractable net assembly, the net assembly comprising at least one net unit; when the net assembly comprises multiple net units, the multiple net units are arranged at axial intervals; each net unit comprises: a net body and multiple pull rods; the net body has a flat net structure with a distally closed end, and the distal ends of the multiple pull rods are respectively connected to the proximal end of the net body; and

[0008] The conveying assembly has a distal end connected to the net unit and a plurality of pull rods of the net unit converging at their proximal ends and connected to the conveying assembly, with an opening in the net unit formed between the plurality of pull rods; the conveying assembly is used to receive the net assembly in a compressed state and is capable of releasing the net assembly to an expanded state and pulling the expanded net assembly back into the conduit.

[0009] In addition, the net assembly includes multiple net units, and the multiple net units are integrally woven from multiple braided filaments.

[0010] In addition, each pull rod of the net unit is a twisted rod structure woven from the multiple braided threads.

[0011] In addition, the main body of the net bag includes a circumferentially closed-loop support section and a distal filter screen that is smoothly connected to the distal end of the support section; the mesh density of the support section is less than the mesh density of the distal filter screen; and the multiple pull rods of the net bag unit are evenly spaced circumferentially to form a conical structure.

[0012] In addition, the core tube includes an elastic telescopic section passing through the distal and proximal ends of the net assembly, and a rigid section connected to the proximal end of the elastic telescopic section.

[0013] In addition, the ratio of the axial length of the pull rod of the net unit to the axial length of the net body is greater than or equal to 0.5 and less than or equal to 5, and the ratio of the maximum diameter of the net body to the axial length of the net body can be greater than or equal to 2 and less than or equal to 20.

[0014] In addition, the tether removal device includes multiple net bag units, each of which is formed by interlacing multiple braided filaments.

[0015] Additionally, the delivery assembly includes a core tube; the net assembly further includes a proximal imaging fixation ring;

[0016] The core tube is inserted through the plurality of net units, and the distal ends of the plurality of net units are connected to the core tube. Multiple braided wires between two adjacent net units are woven into a connecting net tube, which is sleeved on the core tube. Multiple pull rods of the proximal net units in the plurality of net units converge and are connected to the proximal developing and fixing ring, which is fixedly sleeved on the core tube.

[0017] In addition, the conveying assembly also includes:

[0018] The operating handle is a hollow tubular structure with a groove extending along its own axis on its peripheral wall.

[0019] A sheath, the proximal end of which is movably inserted through the operating handle and used to house the net assembly in a retracted state;

[0020] A sheath connector, which is a tubular structure and disposed at the distal end of the operating handle, is connected at its distal end to the proximal end of the sheath. A core tube passes through the sheath and the sheath connector and is sealed to the proximal end of the sheath connector, and is axially movable relative to the sheath and the sheath connector. The proximal end of the core tube protrudes and is fixed to the proximal end of the operating handle.

[0021] A drive unit is disposed within the slide groove. The inner end of the drive unit is connected to the sheath tube connector and can drive the sheath tube connector to move the sheath tube along the slide groove within the operating handle towards the proximal end, so as to release the net assembly.

[0022] In addition, the operating handle includes a first housing and a second housing that are snapped together;

[0023] Both the first outer shell and the second outer shell are provided with positioning posts and positioning holes; the positioning posts and the positioning holes cooperate to make the first outer shell and the second outer shell aligned and snapped together.

[0024] As can be seen from the above technical solution, the present invention has at least the following advantages and positive effects:

[0025] The thrombectomy device of this invention includes a net bag assembly that can include one or more net bag units. The multiple net bag units are arranged at intervals along the axial direction. The net bag body of each net bag unit adopts a flat net bag structure with a closed distal end, and its proximal end is provided with multiple pull rods that converge and connect to the delivery component. This allows each net bag unit to not only have a large opening to facilitate the entry of thrombi into the net bag body, but also to select a thrombectomy device with an appropriate number of net bag units according to the length of the thrombus, so as to catch the thrombus in segments and remove it completely. Therefore, the thrombectomy device of this invention helps to improve the success rate of thrombectomy in one attempt, and can effectively prevent the thrombus from breaking and escaping to block distal blood vessels, thus having a better thrombectomy effect. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. It is understood that the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the thrombectomy device provided in an embodiment of the present invention;

[0028] Figure 2 This is a three-dimensional structural schematic diagram of the net bag assembly of a tether removal device according to an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of the structure of the net bag assembly of the thrombus removal device provided in an embodiment of the present invention;

[0030] Figure 4 A schematic diagram of the braided structure of the pull rod of the net bag unit of the tethering device provided in an embodiment of the present invention;

[0031] Figure 5a , 5b These are schematic diagrams of the weaving structure of the net bag unit of the tethering device provided in an embodiment of the present invention;

[0032] Figure 6 This is a schematic diagram of the thrombectomy device provided in another embodiment of the present invention;

[0033] Figure 7 This is a schematic diagram of the delivery assembly of the thrombectomy device provided in an embodiment of the present invention;

[0034] Figure 8 An exploded view of the delivery assembly of the thrombectomy device provided in an embodiment of the present invention;

[0035] Figure 9 A schematic diagram of the connection structure between the sheath and the core tube of the delivery assembly of the thrombectomy device provided in an embodiment of the present invention;

[0036] Figure 10 A partial structural schematic diagram of a tack-removing device with the net assembly in a compressed state, provided in an embodiment of the present invention;

[0037] Figure 11 This is a schematic diagram of the net assembly in a released state provided in an embodiment of the present invention. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been presented in the various embodiments of the present invention to enable the reader to better understand the present invention. However, the technical solutions claimed in the present invention can be implemented even without these technical details and various changes and modifications based on the following embodiments.

[0039] In the description of this application, the orientation or positional relationship indicated by various terms such as "center", "upper", "lower", "inner", and "outer" is based on the orientation or positional relationship shown in the accompanying drawings and is only for the convenience of description. It is not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed or operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0040] It should be noted that, unless otherwise explicitly stated, the terms “connected” and “linked” should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components.

[0041] Unless otherwise specified, the terms "proximal end" and "distal end" mentioned in this invention have the same meaning in terms of orientation. That is, in the state of use, the distal end is the end away from the operator, and the proximal end is the end closer to the operator. The operator controls the thrombectomy device at the proximal end.

[0042] Please see Figures 1-3 As shown, this embodiment of the invention provides a thrombectomy device suitable for the removal of intravascular thrombi, especially for the rapid removal of large thrombi. Figures 1 to 3 As shown, the thrombectomy device in this embodiment mainly includes: an expandable and retractable net assembly and a conveying assembly connected to the net assembly.

[0043] The net assembly includes at least one net unit 1. The net unit 1 is an expandable and contractible thrombectomy structure capable of capturing and pulling the thrombus from its distal end out of the body. The expansion capability of the net unit 1 can be formed using shape memory materials.

[0044] The net assembly may include a net unit 1, suitable for removing small amounts of thrombus. The net assembly may also include multiple net units 1, arranged axially at intervals. In this case, each net unit 1 can carry the thrombus out of the body in segments. The number of net units 1 can be determined based on the thrombus length and the thrombectomy length of each net unit, to achieve rapid removal of large amounts of thrombus.

[0045] Each net unit 1 includes a net body 11 and a plurality of pull rods 12. The net body 11 has a flat net structure with a closed distal end, and the distal ends of the plurality of pull rods 12 are respectively connected to the proximal ends of the net body 11. The distal end of the net unit 1 is connected to a conveying assembly, and the proximal ends of the plurality of pull rods 12 of the net unit 1 converge and are connected to the conveying assembly, forming an opening in the net unit 1 between the plurality of pull rods 12. The conveying assembly is also used to receive the net assembly in a compressed state, and to release the net assembly to an expanded state and to pull the expanded net assembly back into the conduit.

[0046] like Figure 11 As shown, when the net assembly is released to the thrombectomy position in the blood vessel, the net body 11 of the net unit 1 can expand, and the peripheral wall of the net body 11 can adhere to the inner wall of the blood vessel. The thrombus can enter the net body 11 through the opening between the multiple pull rods 12 and be caught by the net body 11. Then, the net assembly and the thrombus are withdrawn into the catheter 100 through the delivery assembly, so that the thrombus can be taken out of the body.

[0047] Optionally, multiple pull rods 12 of each net unit 1 are evenly spaced along the circumference and form a conical structure, so that the net body 11 is subjected to uniform force and it is easy for the net body 11 to be put into the conduit 100.

[0048] Each net unit 1 can remove thrombi within a certain length of blood vessel. This length can be the length of the blood vessel between the proximal end of the net unit 1 at its maximum diameter and the distal end of the catheter, or the length of the blood vessel between the maximum diameters of the distal and proximal ends of adjacent net units 1. In this embodiment, the net assembly can include two net units. It is understood that the number of net units 1 can be more, such as four, to meet the needs of thrombectomy within longer blood vessel lengths.

[0049] The net body 11 of the net unit 1 is used to pull out thrombi within the length of the vessel it is responsible for along the inner wall of the blood vessel. When the net body 11 has an ellipsoidal flat structure, it can not only provide good support performance, but also have a large opening, which facilitates the entry of thrombi into the net body 1 and their containment. The multiple pull rods 12 of the net unit 1 are used to pull the net body 11. At the same time, by adjusting the axial length of the pull rods 12, i.e., the taper of the multiple pull rods, the retraction of the net body 11 into the catheter can be better controlled. Optionally, the ratio of the axial length of the pull rods 12 to the axial length of the net body 11 can be greater than or equal to 0.5 and less than or equal to 5, and the ratio of the maximum diameter of the net body 11 to the axial length of the net body 11 can be greater than or equal to 2 and less than or equal to 20, so that the net unit as a whole has a flat umbrella shape or onion shape, thereby giving the net unit better thrombectomy performance.

[0050] Multiple mesh units 1 can be formed by interlacing multiple braided filaments. The interlaced filaments form mesh openings, which can be regular polygonal structures such as rhombuses or rectangles. The number of braided filaments can be even. The braided filaments can be shape memory metal wires, such as nickel-titanium alloy wires, or a combination of shape memory metal wires and polymer wires.

[0051] Please see Figure 5a The mesh density of the 11 surrounding walls of the net body can be the same. As an alternative example, the mesh density of the 11 surrounding walls of the net body can also vary; please refer to [link to relevant documentation]. Figure 5bThe mesh density at the distal end of the net body 11 is less than that at the proximal end. Furthermore, the net body 11 includes a circumferentially closed-loop support segment 111 and a distal filter 112 smoothly connected to the distal end of the support segment 111. The mesh density of the support segment 111 can be less than that of the distal filter 112, thereby giving the net body better adhesion to the wall and better preventing thrombus leakage. It should be noted that the proximal end of the support segment 111 of the net body 11 can be further woven into a net bag closing segment, with the distal ends of multiple pull rods 12 connected to the proximal ends of the net bag closing segment.

[0052] Please see Figure 4 Each pull rod 12 of the net bag unit 1 can be a twisted rod structure woven from multiple braided threads. The number of pull rods in the net bag unit can be determined according to the difficulty of the weaving process and the pullback performance. For example, the number of pull rods 12 in each net bag unit can be 3 or 4. During weaving, an even number of braided threads can be used to weave the main structure of the net bag unit first. Then, the even number of braided threads of the main body of the net bag can be evenly combined and wound into a twisted rod structure. When it is necessary to continue weaving the next net bag unit, the braided threads of the twisted rod structure can be dispersed, and then the weaving of the next net bag unit can be carried out.

[0053] Please see Figures 7-9 The delivery assembly may include: a core tube 2, a guide head 3, an operating handle 5, a sheath tube 4, a sheath tube connector 6, and a drive unit 7. The net assembly may also include a proximal imaging retaining ring 13. Please refer to [link / reference needed]. Figure 6 When the net assembly includes one net unit, the core tube 2 passes through the net unit 1, and the distal end of the net unit 1 is connected to the core tube 2. Multiple pull rods 12 converge at their proximal ends to connect to a proximal developing and fixing ring 13, which is fixedly fitted onto the core tube 2. Please continue reading. Figure 1 When the netting assembly includes multiple netting units 1, the multiple netting units 2 are arranged axially at intervals and integrally connected. A core tube 2 passes through the multiple netting units 1, and the distal ends of the multiple netting units 1 are connected to the core tube 2. Multiple braided wires between adjacent netting units 1 are woven into a connecting netting tube 14, which is sleeved on the core tube 2. Multiple pull rods 12 of the proximal netting unit 1 converge and connect to a developing fixing ring 13, which is fixedly sleeved on the core tube 2. For example, the netting assembly may include two netting units 1, with the core tube 2 sequentially passing through the two netting units 1, and the distal end of the farthest netting unit 1 connected to the core tube 2. The two netting units 1 are connected by the connecting netting tube 14, and the proximal ends of the multiple pull rods 12 of the proximal netting unit 1 converge and connect to the proximal developing fixing ring 13, which is fixedly sleeved on the core tube 2.

[0054] It should be noted that each of the multiple net bag units 1 can be formed by interlacing multiple braided filaments and then connected to the core tube 2 respectively. The braided filaments between adjacent net bag units can be connected to the core tube 2 through a developing fixing ring.

[0055] It is worth mentioning that the core tube 2 may include an elastic telescopic section passing through the net assembly and a rigid section connected to the proximal end of the elastic telescopic section. The length of the elastic telescopic section can be determined according to the elasticity of the material and the required range of expansion. The elastic telescopic section of the core tube 2 can expand and contract axially with the net assembly, thereby utilizing the characteristic that the net assembly compresses radially when it extends axially and expands radially when it shortens axially to accommodate and release the net assembly. This not only makes it easy to store and release, but also prevents the expanded shape of the net assembly from easily deforming. The materials used to make the elastic telescopic section of the core tube 2 include, but are not limited to: pebax (nylon elastomer), TPU (Thermoplastic Polyurethanes), TPE (Thermoplastic Elastomer), or silicone. The proximal end of the elastic telescopic section of the core tube 2 can be connected to the rigid section by heat welding or other physical connection methods. It is understood that the core tube 2 as a whole can also adopt a rigid structure.

[0056] The guide head 3 is connected to the distal end of the core tube 2. The distal end of the guide head 3 is a pointed tip and can adopt a conical head structure, thereby improving the propulsion ability of the thrombectomy device in the blood vessel.

[0057] The operating handle 5 is a hollow tubular structure with a groove extending along its axial direction on its peripheral wall. The proximal end of the sheath 4 is movably inserted into the operating handle 5. The sheath connector 6 is a tubular structure located inside the operating handle 5 on the distal side, with its distal end connected to the proximal end of the sheath 4. The core tube 2 is inserted into the sheath 4 and the sheath connector 6 and is sealed to the proximal end of the sheath connector 6, and can move axially relative to the sheath 4 and the sheath connector 6. The proximal end of the core tube 2 protrudes and is fixed to the proximal end of the operating handle 5. The driving member 7 is located in the groove, with its inner end connected to the sheath connector 6 and its outer end protruding outside the groove. The driving member 7 can drive the sheath connector 6 to move the sheath 4 along the groove within the operating handle 5 towards the proximal end to release the net assembly. That is, the driving member 7 can drive the sheath 4 to slide axially relative to the core tube 2 within the operating handle 5.

[0058] The operating handle 5 can be designed to be shaped and sized for easy gripping, and the drive component 7 can be designed to be shaped and sized for easy finger operation. By gripping the operating handle 5 and pulling back the drive component 7, the sheath 4 can be moved proximally along the groove within the operating handle 5 to release the net assembly into an expanded state, facilitating the removal of the tether. It is understood that the sheath connector 6 and the operating handle 5 can be locked together by friction or by other locking structures to prevent unauthorized movement of the sheath 4.

[0059] Please continue reading. Figure 8 The operating handle 5 may include a first housing 51 and a second housing 52 that are snapped together.

[0060] Both the first outer shell 51 and the second outer shell 52 are provided with positioning posts and positioning holes. The positioning posts and positioning holes cooperate to align and engage the first outer shell 51 and the second outer shell 52. For example, the second outer shell 52 is provided with positioning posts 522 and positioning holes 521, and correspondingly, the first outer shell 51 is provided with corresponding positioning holes and positioning posts. The first outer shell 51 and the second outer shell 52 can be aligned and engaged through their respective positioning posts and positioning holes. It is understood that the first outer shell 51 and the second outer shell 52 can also be aligned and engaged through other positioning structures, and no specific limitations are made here.

[0061] Optionally, the inner walls of the first housing 51 and / or the second housing 52 are provided with a number of intersecting reinforcing ribs 523 to improve the overall strength of the operating handle 5 and better meet the operating requirements.

[0062] Please see Figure 8 The delivery assembly may further include an O-ring 61 disposed between the inner wall of the proximal end of the sheath connector 6 and the outer wall of the core tube 2. The sheath connector 6 and the core tube 2 are sealed together by the O-ring 61. That is, the core tube 2 and the proximal end of the sheath connector 6 are sealed and slidingly connected, which can ensure the flexibility of the sheath 4 retraction operation and prevent blood leakage during the operation.

[0063] For example, the drive unit 7 may include two operating buttons symmetrically arranged on the sheath connector 6, and correspondingly, a slide groove is symmetrically arranged on the periphery of the operating handle 5. Each operating button may include a connecting rod 71 and an operating part 72. The connecting rod 72 is located in the slide groove and can move along the slide groove. One end of the connecting rod 72 is connected to the sheath connector 61, and the other end is connected to the operating part 71. The connecting rod 72 can move within the slide groove, and the operating part 71 is located outside the slide groove. Specifically, the operating part 71 may adopt a strip-shaped or sheet-shaped structure bent into a structure with a cross-section that is approximately triangular. The side wall of the operating part 71 parallel to the slide groove is connected to the outer end of the connecting rod 72, and the other two side walls of the operating part 71 can be used as operating surfaces for finger operation to drive the sheath connector 6 to move axially within the operating handle 5.

[0064] Optionally, the operating part 71 is also provided with anti-slip texture 73 to prevent fingers from slipping during operation.

[0065] For example, the operating handle 5 has a roughly chamfered rectangular cross-section. A groove is symmetrically arranged on two parallel sidewalls of the operating handle 5. The operating handle 5 also has graduations indicating the distance the sheath 4 moves axially along the operating handle 5. These graduations can be located on the two symmetrical rectangular sidewalls of the operating handle 5, allowing the operator to observe the distance the sheath 4 retracts (i.e., moves proximally) from either side of the operating handle 5 during operation, thus monitoring the release of the net assembly. It is understood that graduations may also be provided only on one side of the operating handle 5; no specific limitation is made here. The length of the groove represents the range of movement of the sheath 4 relative to the core tube 2.

[0066] The delivery assembly may further include a stress diffusion sleeve 53, which is fitted onto the sheath 4 and fixed to the proximal end of the operating handle 5. The stress diffusion sleeve 53 is used to prevent the sheath 4 from buckling during advancement. Specifically, the distal end of the stress diffusion sleeve 53 has an annular boss, and the inner wall of the proximal end of the operating handle 5 has an annular groove. The annular boss and the annular groove cooperate to fix the stress diffusion sleeve 5 to the operating handle 5. The stress diffusion sleeve 53 may be made of silicone material.

[0067] Optionally, the delivery device may further include an infusion tube, a first Luer connector 8, and a second Luer connector 9. One end of the infusion tube is connected to the peripheral wall of the sheath connector 6 and communicates with the gap between the sheath 4 and the core tube 2. The other end of the infusion tube is connected to the first Luer connector 8. By way of example and not limitation, the infusion tube may move within a groove, i.e., the infusion tube and the drive component are located in the same groove. The second Luer connector 9 is connected to the proximal end of the core tube 2, and the distal end of the second Luer connector 9 is fixedly connected to the proximal end of the operating handle 5, thereby fixing the proximal end of the core tube 2 to the sheath connector 6. Both the first Luer connector 8 and the second Luer connector 9 may be single-port or multi-port Luer connectors. Physiological saline can be injected into the gap between the sheath 4 and the core tube 2 through the first Luer connector 8 and the infusion tube to expel air from the gap between the sheath 4 and the core tube 2. Physiological saline can be injected into the core tube 2 through the second Luer connector 9 to expel air from the core tube 2. Of course, thrombolytic agents or other functional liquids can also be injected into the infusion tubing and core tube 2, without specific restrictions.

[0068] Combination Figure 1 , Figure 10 as well as Figure 11 The method of using the thrombectomy device in this embodiment is as follows:

[0069] The thrombectomy device of this embodiment can be used in conjunction with the catheter 100. Before the operation, saline solution is injected into the first Luer connector 8 and the second Luer connector 9 using a syringe to purge the air from the sheath 4 and the core tube 2. After the catheter 100 is advanced into place along the pre-implanted guidewire, the sheath 4 with the mesh assembly is inserted into the catheter 100 along the guidewire and advanced to the thrombectomy position. Then, the drive is operated to pull back the sheath 4, at which point the mesh assembly is released. The degree of release of the mesh assembly can be judged by the scale lines on the operating handle 5. After the mesh assembly is completely released, the operating handle 5 is withdrawn to pull the mesh assembly and the thrombus back into the catheter 100 and out of the body.

[0070] Based on the above technical solution, the present invention has at least the following advantages and positive effects:

[0071] The thrombectomy device of this invention includes a net bag assembly that can include one or more net bag units. The multiple net bag units are arranged at intervals along the axial direction. The net bag body of each net bag unit adopts a flat net bag structure with a closed distal end, and its proximal end is provided with multiple pull rods that converge and connect to the delivery component. This allows each net bag unit to not only have a large opening to facilitate the entry of thrombi into the net bag body, but also to select a thrombectomy device with an appropriate number of net bag units according to the length of the thrombus, so as to catch the thrombus in segments and remove it completely. Therefore, the thrombectomy device of this invention helps to improve the success rate of thrombectomy in one attempt, and can effectively prevent the thrombus from breaking and escaping to block distal blood vessels, thus having a better thrombectomy effect.

[0072] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of the present invention.

Claims

1. A device for removing a thrombus, characterized in that include: An expandable and retractable mesh assembly, the mesh assembly comprising at least one mesh unit; When the net assembly includes multiple net units, the multiple net units are arranged at intervals along the axial direction; each net unit includes: a net body and multiple pull rods; the net body has a flat net structure with the distal end closed, and the distal ends of the multiple pull rods are respectively connected to the proximal end of the net body; and A conveying assembly is provided, wherein the distal end of the net unit is connected to the conveying assembly, and the proximal ends of a plurality of pull rods of the net unit converge and are connected to the conveying assembly, with an opening of the net unit formed between the plurality of pull rods; the conveying assembly is used to receive the net assembly in a compressed state, and is capable of releasing the net assembly to an expanded state and pulling the expanded net assembly back into the guide tube; The net assembly includes multiple net units, and the multiple net units are integrally woven from multiple braided filaments; Each pull rod of the net unit is a twisted rod structure woven from multiple braided threads; The net bag body includes a circumferentially closed-loop support section and a distal filter screen that is smoothly connected to the distal end of the support section; the mesh density of the support section is less than the mesh density of the distal filter screen; multiple pull rods of the net bag unit are evenly spaced circumferentially and form a conical structure. The ratio of the axial length of the pull rod of the net unit to the axial length of the net body is greater than or equal to 0.5 and less than or equal to 5, and the ratio of the maximum diameter of the net body to the axial length of the net body is greater than or equal to 2 and less than or equal to 20. The delivery assembly includes a core tube; the net assembly further includes a proximal imaging and fixing ring. The core tube passes through the plurality of net units, and the distal ends of the plurality of net units are connected to the core tube. Multiple braided filaments between two adjacent net units are woven into a connecting net tube, which is sleeved on the core tube. Multiple pull rods of the proximal net units in the plurality of net units converge and are connected to the proximal developing and fixing ring, which is fixedly sleeved on the core tube. The core tube includes an elastic telescopic section passing through the net assembly and a rigid section connected to the proximal end of the elastic telescopic section.

2. The thrombectomy device of claim 1, wherein, The conveying assembly also includes: The operating handle is a hollow tubular structure with a groove extending along its own axis on its peripheral wall. A sheath, the proximal end of which is movably inserted through the operating handle and used to house the net assembly in a retracted state; A sheath connector, which is a tubular structure and disposed at the distal end of the operating handle, is connected at its distal end to the proximal end of the sheath. A core tube passes through the sheath and the sheath connector and is sealed to the proximal end of the sheath connector, and is axially movable relative to the sheath and the sheath connector. The proximal end of the core tube protrudes and is fixed to the proximal end of the operating handle. A drive unit is disposed within the slide groove. The inner end of the drive unit is connected to the sheath tube connector and can drive the sheath tube connector to move the sheath tube along the slide groove within the operating handle towards the proximal end, so as to release the net assembly.

3. The thrombectomy device of claim 2, wherein, The operation handle comprises a first shell and a second shell which are clamped together; The first shell and the second shell are both provided with positioning columns and positioning holes; the positioning columns and the positioning holes are matched to align and clamp the first shell and the second shell.

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