Thrombus filtering device

Abstract

A thrombus filtering device, comprising: an outer sheath tube (201), a middle sheath tube (202), a proximal filter (204), an inner sheath tube (203) and a distal filter (205). The middle sheath tube (202) comprises a pushing tube (2021) and a steerable tube, the distal end of the pushing tube (2021) being connected to the proximal end of the steerable tube, and the proximal filter (204) being connected to the pushing tube (2021). The outer sheath tube (201) is movably sleeved outside the middle sheath tube (202). The distal filter (205) is connected to the distal end of the inner sheath tube (203); and the inner sheath tube (203) movably penetrates through the middle sheath tube (202), and comprises a proximal delivery tube (2033) and a distal fixing tube (2032) which are connected to each other, the distal fixing tube (2032) being a metal tube and comprising a spring tube section (20321).

Description

Thrombus filtration device

[0001] Related applications

[0002] This application claims priority to the Chinese patent application filed on December 25, 2023, with application number 202311796401.8 and title “Thrombus Filtering Device”, the relevant contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of medical device technology, and in particular to a thrombus filtering device. Background Art

[0004] In the human body, brain cells have a high demand for oxygen in the blood. Four arteries deliver oxygenated blood to the brain, supplying it. Referring to Figure 1 , these arteries are the left vertebral artery 111, the left common carotid artery 12, the right vertebral artery 113, and the right common carotid artery 112.

[0005] With the increasing popularity of heart and aorta-related surgeries, such as transcatheter aortic valve replacement and mitral valve annuloplasty, these surgeries may directly or indirectly cause the shedding of some substances, such as platelets, fibrinogen, fibrocartilage, bacterial clots and other small pieces of tissue, during the process.

[0006] These detached substances may flow along the arteries to the brain with the blood. When the arteries are blocked by these substances, they cause tissue ischemia, further triggering cerebral vascular embolism, leading to myocardial infarction, stroke, or even death. Currently, cerebral vascular embolism has become a very common complication of aortic valve surgery14 (Figure 1) and other heart surgeries.

[0007] Therefore, in some related technical solutions, in order to reduce the complications of cerebral vascular embolism caused by cardiac surgery, a thrombus filtration device with a filter is implanted in the blood vessels supplying blood to the brain to prevent cerebral embolism. A typical thrombus filtration device includes a proximal filter and a distal filter. The proximal filter needs to be placed in the brachiocephalic artery 13, and the distal filter needs to be placed in the left common carotid artery 12.

[0008] However, arterial vessels vary in length, angle, etc. Conventional thrombus filtering devices have a fixed relative distance between the proximal and distal filters, making it difficult to place them in appropriate locations in the arteries of different patients.

[0009] Summary of the Invention

[0010] Based on this, it is necessary to provide a thrombus filtering device to address the problem that the relative distance between the proximal filter and the distal filter of the thrombus filtering device in the prior art is fixed, making it difficult to place them in appropriate vascular positions in the arteries of different patients.

[0011] The present application provides a thrombus filtering device, which comprises: an outer sheath, an intermediate sheath, a proximal filter, an inner sheath, and a distal filter;

[0012] The intermediate sheath tube includes a push tube and a bend adjustment tube, the distal end of the push tube is connected to the proximal end of the bend adjustment tube, the proximal filter is connected to the push tube, and the outer sheath tube is movably sleeved outside the intermediate sheath tube;

[0013] The distal filter is connected to the distal end of the inner sheath tube, and the inner sheath tube is movably arranged in the middle sheath tube;

[0014] The inner sheath tube comprises a proximal delivery tube and a distal fixing tube connected to each other, wherein the distal fixing tube is a metal tube; the distal fixing tube comprises a spring tube segment.

[0015] In one embodiment, the distal fixing tube includes a cutting tube segment, and the cutting tube segment is provided with a plurality of cutting grooves sequentially arranged along the axial direction.

[0016] In one embodiment, the proximal filter includes a first elastic metal skeleton and a first polymer membrane, the first polymer membrane includes a first porous filter membrane, the first porous filter membrane is covered on the first elastic metal skeleton, the first porous filter membrane has a contracted state and an expanded state, and the first porous filter membrane is contracted from the distal end to the proximal end in the expanded state.

[0017] In one embodiment, the distal filter includes a second elastic metal skeleton and a second polymer membrane, and the second polymer membrane includes a second porous filter membrane; the second porous filter membrane is connected to the second elastic metal skeleton, and the second porous filter membrane has a contracted state and an expanded state, and the second porous filter membrane is contracted from the proximal to the distal direction in the expanded state.

[0018] In one embodiment, the first elastic metal skeleton includes a first support ring, a first support wire and a first fixing wire, the distal end of the first porous filter membrane is connected to the first support ring and the shapes of the two are adapted; the first fixing wire is fit and fixed to the push tube, the proximal end of the first support wire is connected to the first fixing wire, and the distal end of the first support wire is connected to the first support ring.

[0019] In one embodiment, the first polymer membrane further includes a support membrane, and the support membrane surrounds and is attached to the proximal end of the first porous filter membrane.

[0020] In one embodiment, the first polymer membrane further includes an inner sleeve segment, which is sleeved on and attached to the push tube, and the proximal end of the first porous filter membrane is sleeved on and attached to the inner sleeve segment.

[0021] In one embodiment, the first polymer membrane further includes an outer casing segment, which is sleeved and attached to the proximal end of the first porous filter membrane.

[0022] In one embodiment, the inner sheath comprises a proximal delivery tube and a distal fixing tube connected to each other. The distal fixing tube is a metal tube and is used to fix the distal filter.

[0023] In one embodiment, the inner sheath tube includes a head end tube, the head end tube is a polymer tube, and the proximal end of the head end tube is connected to the distal end of the distal fixing tube;

[0024] The distal end of the second elastic metal skeleton is connected to the proximal end of the second porous filter membrane and supports the shape of the proximal end of the second porous filter membrane. The distal end of the second porous filter membrane is connected to the head end tube, and the second elastic metal skeleton is connected to the distal fixed tube.

[0025] In one embodiment, the second polymer membrane includes a head end cap, which is connected to the distal end of the second porous filter membrane and wraps the distal end of the head end tube.

[0026] In one embodiment, the second elastic metal skeleton includes a second support ring, a second support wire and a second fixing wire, the proximal end of the second porous filter membrane is connected to the second support ring and the shapes of the two are adapted; the second fixing wire is fit and fixed to the distal fixing tube, the proximal end of the second support wire is connected to the second fixing wire, and the distal end of the second support wire is connected to the second support ring.

[0027] When the above-mentioned thrombus filtering device is used, it is first adjusted to a retracted state, and then inserted into the right subclavian artery and brachiocephalic artery by puncturing the radial artery; then, by withdrawing the outer sheath, the proximal filter is exposed from the distal end of the outer sheath to be placed in the brachiocephalic artery; then, by moving the inner sheath distally relative to the intermediate sheath and extending it into the aortic arch, the proximal filter is exposed from the distal end of the bending tube. The bending tube is then bent, so that the distal filter extending out of the bending tube enters the left common carotid artery from the aortic arch as the bending tube bends, while the proximal filter can be retained in the brachiocephalic artery. Among them, since the inner sheath can move relative to the intermediate sheath, the relative distance between the distal filter set on the inner sheath and the proximal filter set on the intermediate sheath can be adjusted, and thus the relative distance between the proximal filter and the distal filter can be adjusted. In this way, the above-mentioned thrombus filtering device can adjust the relative distance between the proximal filter and the distal filter according to the actual conditions of the blood vessels of different patients, so that both the proximal filter and the distal filter can be quickly and accurately placed in the appropriate blood vessel position, thereby making the above-mentioned thrombus filtering device flexible to adapt to the arterial blood vessels of different patients. Moreover, since the inner sheath can move relative to the middle sheath, the proximal filter and the distal filter can move relatively independently, which facilitates the independent adjustment of the positions of the proximal filter and the distal filter. In the process of retrieving the spring tube segment into the bending tube, it can adapt to the bending part of the bending tube through its elastic bending deformation, thereby facilitating the inner sheath to carry the distal filter back into the bending tube.

[0028] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the disclosed drawings without any creative work.

[0030] FIG1 is a schematic structural diagram of the aortic arch of a human body.

[0031] FIG2 is a schematic structural diagram of a thrombus filtering device according to an embodiment.

[0032] FIG3 is a schematic diagram showing the relationship between the inner and outer layers of each tube and filter of the thrombus filtering device of FIG2 .

[0033] FIG4 is a schematic diagram of the bending tube of the thrombus filtering device of FIG2 during one bending adjustment.

[0034] FIG5 is a schematic diagram of the bending tube of the thrombus filtering device of FIG2 during double bending.

[0035] FIG6 is a schematic diagram of the thrombus filtering device of FIG2 in use when implanted in a human body.

[0036] FIG7 is a schematic diagram of the recovery state of the thrombus filtering device in FIG2 .

[0037] FIG8 is a schematic structural diagram of a first elastic metal bracket according to an embodiment.

[0038] FIG9 is a partial enlarged view of area A in FIG8 .

[0039] FIG10 is a schematic structural diagram of a first porous filter membrane according to an embodiment.

[0040] FIG. 11 is a schematic diagram showing the connection relationship between the first porous filter membrane in FIG. 10 in an expanded state and the support membrane.

[0041] FIG12 is a schematic structural diagram of a first porous filter membrane, an inner casing section, an outer casing section, and a fixing wire according to an embodiment of the present invention.

[0042] FIG13 is a schematic diagram showing the relationship between the inner and outer layers of the components of the proximal filter according to an embodiment.

[0043] FIG14 is a schematic structural diagram of the distal end fixing section of the inner sheath according to an embodiment.

[0044] FIG15 is a schematic structural diagram of an inner sheath tube according to an embodiment.

[0045] FIG16 is a schematic diagram showing the connection relationship between the inner sheath and the distal filter according to an embodiment.

[0046] FIG17 is a schematic diagram showing the relationship between the inner and outer layers of the components of the inner sheath tube of FIG16 .

[0047] FIG18 is a schematic structural diagram of a second elastic metal bracket according to an embodiment.

[0048] FIG19 is a partial enlarged view of area B in FIG18 .

[0049] FIG20 is a schematic structural diagram of a second porous filter membrane according to an embodiment.

[0050] FIG. 21 is a schematic diagram of the expanded state of the second porous filter membrane in FIG. 20 .

[0051] Explanation of Reference Numerals: 11. Left subclavian artery; 12. Left common carotid artery; 13. Brachiocephalic artery; 14. Aortic valve; 111. Left vertebral artery; 112. Right common carotid artery; 113. Right vertebral artery; 114. Right subclavian artery; 201. Outer sheath; 202. Intermediate sheath; 2021. Push tube; 2022. First tube; 2023. Second tube; 20221. Connector; 20231. Bending wire; 203. Inner sheath; 2031. Head tube; 2032. Distal fixing tube; 20321. Spring tube segment; 20322. Connecting portion; 20323. Cutting tube segment; 20324. Cutting groove; 2033. Proximal delivery tube; 204. Proximal filter; 2041, first elastic metal skeleton; 20411, first support ring; 20411A, connection point; 20411B, connection point; 20412, first support wire; 20413, first fixing wire; 2042, first polymer membrane; 20421, first porous filter membrane; 20422, support membrane; 20423, inner casing segment; 20424, outer casing segment; 205, distal filter; 2051, second elastic metal skeleton; 20511, second support ring; 20511A, connection point; 20511B, connection point; 20512, second support wire; 20513, second fixing wire; 2052, first polymer membrane; 20521, second porous filter membrane; 2053, head cap; 206, first handle; 207, sheath push knob; 208, second handle; 209, filter push knob; 210, bend control knob. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0053] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0055] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0056] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0057] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0058] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0059] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0060] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0061] In the description of the embodiments of the present application, the terms "proximal" and "distal" refer to the relative orientation, relative position, and direction of elements or actions relative to each other from the perspective of a doctor using the medical device. Although "proximal" and "distal" are not restrictive, "proximal" generally refers to the end of the medical device that is close to the doctor during normal operation, and "distal" generally refers to the end that first enters the patient's body.

[0062] Referring to Figure 1 , the aortic arch 15 has three blood vessels: the left subclavian artery 11, the left common carotid artery 12, and the brachiocephalic artery 13. The left subclavian artery 11 branches into the left vertebral artery 111, the brachiocephalic artery 13 has a bifurcation connecting to the right common carotid artery 112 and the right vertebral artery 113, and the brachiocephalic artery 13 also connects to the right subclavian artery 114. During aortic valve replacement 14 or other types of heart surgery, some substances, such as platelets, fibrinogen, fibrocartilage, bacterial clots, and other small pieces of tissue, may be released and flow through the blood vessels above the aortic arch 15. The left vertebral artery 111, right vertebral artery 113, left common carotid artery 12, and right common carotid artery 112, located above the aortic arch 15, supply blood to the brain. If these substances flow along these four vessels to the brain, various complications can occur.

[0063] 2 to 7 , an embodiment of the present application provides a thrombus filtering device, which includes: an outer sheath 201 , an intermediate sheath 202 , a proximal filter 204 , an inner sheath 203 , and a distal filter 205 .

[0064] The intermediate sheath 202 includes a push tube 2021 and a bend adjustment tube. The distal end of the push tube 2021 is connected to the proximal end of the bend adjustment tube. The proximal filter 204 is connected to the push tube 2021. The outer sheath 201 is movably mounted outside the intermediate sheath 202 to mount or expose the proximal filter 204. Specifically, by retracting the outer sheath 201 proximally relative to the intermediate sheath 202, the proximal filter 204 can be exposed from the distal end of the outer sheath 201. Conversely, by moving the outer sheath 201 distally, the outer sheath 201 can be mounted outside the proximal filter 204. The push tube 2021 is used to push the bend adjustment tube, thereby achieving the overall movement of the intermediate sheath 202.

[0065] The distal filter 205 is connected to the distal end of the inner sheath 203. The inner sheath 203 is movably disposed within the intermediate sheath 202, thereby driving the distal filter 205 to extend or retract from the bend. Specifically, moving the inner sheath 203 distally relative to the intermediate sheath 202 exposes the proximal filter 204 from the distal end of the bend. Conversely, moving the inner sheath 203 proximally retracts the proximal filter 204 into the bend.

[0066] The bend adjustment tube can be bent so that the distal filter 205 extending out of the bend adjustment tube can be located in the left common carotid artery 12, and the proximal filter 204 can be located in the brachiocephalic artery 13. Specifically, a bend adjustment pull wire 20231 can be provided, the distal end of the bend adjustment pull wire 20231 is connected to the bend adjustment tube, the bend adjustment pull wire 20231 passes through the bend adjustment tube and the push tube 2021, and the bend adjustment pull wire 20231 is pulled from the proximal end of the bend adjustment pull wire 20231, thereby driving the bend adjustment tube to bend.

[0067] Referring to Figures 14 to 16 , the inner sheath 203 includes a proximal delivery tube 2033 and a distal fixing tube 2032, the distal end of which is connected to the proximal end of the distal fixing tube 2032. The distal fixing tube 2032 is a metal tube and is used to secure the distal filter 205. Specifically, it can be connected to the distal filter 205 by welding, bonding, or other methods. The distal fixing tube 2032 includes a spring tube segment 20321, which can be a coil spring.

[0068] The thrombus filtering device has a recovery state and an in-use state. In the recovery state (see FIG7 ), the distal filter 205 is retracted into the bend tube, and the outer sheath 201 is positioned over the proximal filter 204 to facilitate entry and withdrawal from a human blood vessel. In the in-use state (see FIG5 ), the distal filter 205 is extended from the bend tube, and the outer sheath 201 exposes the proximal filter 204, allowing the proximal and distal filters 204 and 205 to filter within corresponding blood vessels.

[0069] The following describes the process of implanting the aforementioned thrombus filtering device into a patient's body: the thrombus filtering device is initially in a recovered state, puncturing the radial artery and extending into the right subclavian artery 114 and the brachiocephalic artery 13. The outer sheath 201 is then withdrawn, exposing the proximal filter 204 from the distal end of the outer sheath 201 for placement within the brachiocephalic artery 13. The inner sheath 203 is then moved distally relative to the intermediate sheath 202 and extended into the aortic arch 15, exposing the distal filter 205 from the distal end of the bend tube. The bend wire 20231 is then pulled proximally to bend the bend tube, allowing the distal filter 205 extending from the bend tube to enter the left common carotid artery 12 from the aortic arch 15 as the bend tube bends, while the proximal filter 204 remains within the brachiocephalic artery 13.

[0070] Because the inner sheath 203 can move relative to the intermediate sheath 202, the relative distance between the distal filter 205 disposed on the inner sheath 203 and the proximal filter 204 disposed on the intermediate sheath 202 can be adjusted, and thus the relative distance between the proximal filter 204 and the distal filter 205 can be adjusted. In this way, the thrombus filtering device can adjust the relative distance between the proximal filter 204 and the distal filter 205 according to the actual conditions of the blood vessels of different patients, allowing both the proximal filter 204 and the distal filter 205 to be quickly and accurately placed in the appropriate blood vessel position, thereby enabling the thrombus filtering device to flexibly adapt to the arterial vessels of different patients. Furthermore, because the inner sheath 203 can move relative to the intermediate sheath 202, the proximal filter 204 and the distal filter 205 can move independently of each other, facilitating the independent adjustment of the positions of the proximal filter 204 and the distal filter 205.

[0071] When the thrombus filtering device is in use, the spring tube segment 20321 extends out of the distal end of the bend tube. When the device is removed from the human body after use, it is adjusted to a recovery state, thereby requiring the distal filter 205 to be retracted into the bend tube. Consequently, the spring tube segment 20321 also needs to be retracted into the bend tube. During the process of retraction of the spring tube segment 20321 into the bend tube, it can adapt to the bend of the bend tube through its elastic bending deformation, thereby facilitating the retraction of the inner sheath tube 203, carrying the distal filter 205, into the bend tube.

[0072] As described above, when the outer sheath 201 is pushed distally, the proximal filter 204 can be retracted within it; when the outer sheath 201 is withdrawn proximally, the proximal filter 204 is released for embolic filtration. Therefore, the distal end of the proximal filter 204 does not exceed the maximum distance the outer sheath 201 can be pushed. Similarly, the proximal end of the proximal filter 204 does not exceed the minimum distance the outer sheath 201 can be withdrawn. Optionally, the distance from the distal end of the proximal filter 204 to the proximal end of the push tube 2021 is greater than or equal to 800 mm and less than or equal to 1100 mm.

[0073] Similarly, when the inner sheath 203 is pushed distally, the distal filter 205 can be released for embolic protection; when the inner sheath 203 is withdrawn proximally, the distal filter 205 is retracted into the bend tube. Therefore, the overall length of the distal filter 205 should not be greater than the overall length of the bend tube.

[0074] Optionally, the proximal delivery tube 2033 is a braided tube with high strength, high toughness, and ease of delivery, facilitating delivery of the inner sheath 203. Specifically, the proximal delivery tube 2033 may include an inner layer, an outer layer, and an intermediate layer. The inner and outer layers may be made of polymer materials, such as any one or more of PU, PET, TPU, PTFE, PI, Pebax, etc. The intermediate layer may be made of a metal material woven into a mesh, basket, or spring pattern using a specific process. The intermediate layer may be made of at least one of stainless steel, nickel titanium, nickel, and the like. The inner diameter of the proximal delivery tube 2033 is greater than or equal to 0.2 mm and less than or equal to 0.5 mm; the outer diameter is greater than or equal to 0.4 mm and less than or equal to 0.6 mm.

[0075] Referring to Figures 2 to 7 , in one embodiment, the bending adjustment tube includes a first tube 2022 and a second tube 2023. The proximal end of the first tube 2022 is connected to the distal end of the push tube 2021, and the distal end of the first tube 2022 is connected to the proximal end of the second tube 2023. A bending adjustment wire 20231 can cause the first tube 2022 and the second tube 2023 to bend sequentially, wherein the first tube 2022 bends in a first direction and the second tube 2023 bends in a second direction, which is opposite to the first direction.

[0076] Specifically, the distal end of the bending adjustment wire 20231 can be connected to the second tube 2023, and the bending adjustment wire 20231 passes through the second tube 2023, the first tube 2022 and the push tube 2021. When the bending adjustment wire 20231 is pulled from the proximal end of the bending adjustment wire 20231, the second tube 2023 bends first, and when the bending adjustment wire 20231 is continued to be pulled, the first tube 2022 will also bend accordingly, achieving a double bending effect. Among them, the bending directions of the first tube 2022 and the second tube 2023 are opposite. The double bending can make the bending tube adapt to the spatial shape of the complex physiological structure of the aortic arch 15, so that the proximal filter 204 and the distal filter 205 can be quickly and accurately placed in the brachiocephalic artery 13 and the left common carotid artery 12 respectively.

[0077] The first tube 2022 can be made of a keel structure. The second tube 2023 can be made of a polymer material. As shown in FIG2 , the first tube 2022 and the second tube 2023 can be connected by a connector 20221 .

[0078] Referring to Figures 8 to 13 , in one embodiment, the proximal filter 204 includes a first elastic metal skeleton 2041 and a first polymer membrane 2042. The first polymer membrane 2042 includes a first porous filter membrane 20421. The first porous filter membrane 20421 is coated on the first elastic metal skeleton 2041, which is used to support the shape of the first porous filter membrane 20421. The first porous filter membrane 20421 has a contracted state and an expanded state. In the expanded state, the first porous filter membrane 20421 is contracted from the distal end to the proximal end.

[0079] The first elastic metal skeleton 2041 is an elastic skeleton and can be elastically compressed to retract the proximal filter 204 in a contracted state within the outer sheath 201. When the proximal filter 204 is released from the outer sheath 201, the proximal filter 204 can be elastically restored to an expanded state by the first elastic metal skeleton 2041, thereby expanding the first porous filter membrane 20421. The material of the first elastic metal skeleton 2041 is, for example, at least one metal material such as nickel-titanium alloy and chromium-nickel-inconel alloy.

[0080] When the first porous filter membrane 20421 is stretched by the first elastic metal skeleton 2041, i.e., in the expanded state, it contracts from the distal end toward the proximal end, thereby forming an opening at the distal end of the proximal filter 204, giving the overall shape of an umbrella or triangular pyramid. The first porous filter membrane 20421 has pores of a specific shape and area, which facilitate blood flow and filter emboli.

[0081] The proximal filter 204 is fixed to the push tube 2021 at the proximal end, and can be fixed by bonding, welding, hot melting, etc.

[0082] Preferably, the first porous filter membrane 20421 is covered on the outside of the first elastic metal skeleton 2041. In some cases, the first porous filter membrane 20421 can also be covered on the inside of the first elastic metal skeleton 2041.

[0083] Unlike existing pure metal braided stent filters, the proximal filter 204 in this embodiment uses an elastic metal frame, and a polymer porous filter membrane is disposed on the elastic metal frame. Compared to pure metal braided stent filters, the pore size of the polymer porous filter membrane is more flexible and controllable, and the processing difficulty is lower. At the same time, when achieving the same strength performance requirements, the thickness of the polymer porous filter membrane is much lower than that of the pure metal braided stent (up to 1 / 10), resulting in a smaller space-occupying effect during device delivery and recovery, making it easier to recover and transport.

[0084] Furthermore, due to the thinness and high strength of the polymer porous filter membrane, it is more easily able to filter large-sized thrombi, plaques, and other substances in actual use. Compared to pure metal braided stent filters, under the same filtering conditions, when filtering out larger-sized embolic objects, the structure of the proximal filter 204 of this embodiment is more easily recovered into the outer sheath 201, avoiding partial or no sheathing. At the same time, it greatly reduces the pressure on the outer sheath 201, the inner sheath 203, and the brachiocephalic artery 13 during the recovery process, greatly improving the safety of the product.

[0085] The first porous filter membrane 20421 is made of a polymer material and can be any one or more of PU, PET, TPU, PTFE, etc. The first porous filter membrane 20421 is distributed with pores of a certain pore size, a certain pore spacing, and a certain area. The pore size can be 80-160 μm, and the pore spacing is generally comparable to the pore size, 80-160 μm. The pore area cannot be too large, as this will affect the overall strength and filtration performance of the first porous filter membrane 20421. It cannot be too small, as this will affect the overall blood flow, leading to localized high blood pressure and excessive pressure differentials. The pore area can be two-thirds of the total membrane area, as shown in Figure 11.

[0086] In one embodiment, a first developing ring (not shown) is sleeved on the outer periphery of the distal end of the first elastic metal skeleton 2041. The first developing ring can be made of platinum, platinum-tungsten or platinum-iridium alloy.

[0087] Referring to Figures 8 to 13 , in one embodiment, the first elastic metal skeleton 2041 includes a first support ring 20411, a first support wire 20412, and a first fixing wire 20413. The distal end of the first porous filter membrane 20421 is connected to the first support ring 20411, and the two are shaped to fit together. The first fixing wire 20413 is fixedly attached to the push tube 2021, the proximal end of the first support wire 20412 is connected to the first fixing wire 20413, and the distal end of the first support wire 20412 is connected to the first support ring 20411.

[0088] Optionally, the diameters of the first supporting ring 20411 , the first supporting wire 20412 , and the first fixing wire 20413 are greater than or equal to 0.10 mm and less than or equal to 0.35 mm.

[0089] Optionally, a dimension of the first elastic metal skeleton 2041 along the length direction of the pushing tube 2021 is greater than or equal to 40 mm and less than or equal to 70 mm.

[0090] In its natural state, the first support ring 20411 can be elliptical. Optionally, the major axis of the first support ring 20411 is greater than or equal to 6 mm and less than or equal to 12 mm; the minor axis is greater than or equal to 5 mm and less than or equal to 10 mm. The first support ring 20411 can also be circular in its natural state.

[0091] The first support ring 20411 can be a closed structure or an open ring. As shown in Figures 8 and 9, when the first support ring 20411 is an open ring, the two ends of the opening of the first support ring 20411 are respectively connected to the two first support wires 20412, thereby forming two connection points, namely connection point 20411A and connection point 20411B.

[0092] In the embodiment shown in Figures 8 and 9, there are two first support wires 20412. In other embodiments, the number of first support wires 20412 is not limited to two, and may be one, three, four, etc.

[0093] The first support wire 20412 and the axial end surface of the first support ring 20411 are set at an angle, and the angle between the two can be 60-120 degrees.

[0094] A first reference plane and a first projection plane are defined. The first reference plane is the plane defined by the central axis of the first support ring 20411 and the central axis of the first support wire 20412. The first projection plane is the plane perpendicular to the first reference plane and passing through the central axis of the first support ring 20411. Optionally, the projected length of the first support wire 20412 on the first projection plane is greater than or equal to 15 mm and less than or equal to 25 mm.

[0095] As shown in Figure 8, the first fixing wire 20413 is connected to the first support wire 20412 in a one-to-one relationship. The first fixing wire 20413 can extend in a straight line and be fixed closely to the push tube 2021. The first fixing wire 20413 can also be wrapped around the push tube 2021. Optionally, the projected length of the first fixing wire 20413 on the first projection plane is greater than or equal to 25 mm and less than or equal to 35 mm.

[0096] Specifically, the first developing ring can be sleeved on the first supporting ring 20411, and both ends of the first developing ring are flush with the first supporting ring 20411 to maintain its stability.

[0097] Referring to FIG. 11 , in one embodiment, the first polymer membrane 2042 further includes a support membrane 20422 . The support membrane 20422 surrounds and is attached to the proximal end of the first porous filter membrane 20421 .

[0098] Specifically, the proximal end of the first porous filter membrane 20421 is tubular and is used to be mounted outside the push tube 2021. The support membrane 20422 is arranged around and attached to the outer periphery of the proximal tubular structure to protect the proximal end of the first porous filter membrane 20421, thereby minimizing wear of the proximal filter 204 during movement.

[0099] The support film 20422 is made of a polymer material and can be any one or more of PU, PET, TPU, PTFE, etc.

[0100] Optionally, the length of the support film 20422 is greater than or equal to 15 mm and less than or equal to 35 mm; the width is greater than or equal to 1 mm and less than or equal to 5 mm.

[0101] Referring to Figures 12 and 13 , in one embodiment, the first polymer membrane 2042 further includes an inner sleeve segment 20423, which is sleeved and attached to the push tube 2021. The proximal end of the first porous filter membrane 20421 is sleeved and attached to the inner sleeve segment 20423. This positions the inner sleeve segment 20423 as the innermost layer of the proximal filter 204. The inner sleeve segment 20423 facilitates the connection between the proximal end of the first porous filter membrane 20421 and the push tube 2021. Optionally, the inner sleeve segment 20423 has an inner diameter greater than or equal to 1 mm and less than or equal to 1.2 mm; an outer diameter greater than or equal to 1.1 mm and less than or equal to 1.4 mm; and a length greater than or equal to 8 mm and less than or equal to 12 mm.

[0102] Referring to Figures 12 and 13 , in one embodiment, the first polymer membrane 2042 further includes an outer sleeve segment 20424, which is fitted over and attached to the proximal end of the first porous filter membrane 20421. This positions the outer sleeve segment 20424 at the outermost edge of the proximal filter 204, protecting and securing the proximal end of the proximal filter 204. The outer sleeve segment 20424 has an inner diameter greater than or equal to 1.4 mm and less than or equal to 1.6 mm, an outer diameter greater than or equal to 1.5 mm and less than or equal to 1.8 mm, and a length greater than or equal to 8 mm and less than or equal to 20 mm.

[0103] In one embodiment, when the thrombus filtering device is in use, the spring tube segment 20321 extends out of the second tube 2023. During the process of retracting the spring tube segment 20321 into the second tube 2023, it elastically deforms to conform to the curve of the second tube 2023, thereby facilitating the retraction of the inner sheath 203, carrying the distal filter 205, into the bendable tube. The length of the spring tube segment 20321 is greater than or equal to 5 mm and less than or equal to 10 mm.

[0104] 14 to 16 , in one embodiment, the distal fixing tube 2032 includes a cutting tube segment 20323, which is used to secure the distal filter 205, thereby facilitating the securing of the distal filter 205 to the distal fixing tube 2032. The cutting tube segment 20323 is provided with a plurality of cutting grooves 20324 arranged in sequence along the axial direction.

[0105] When the thrombus filtering device is in use, the cut tube section 20323 extends out of the distal end of the bend tube. When the device is removed from the human body after use, it needs to be adjusted to a recovery state, thereby recovering the distal filter 205 into the bend tube, and thus also recovering the cut tube section 20323 into the bend tube.

[0106] By providing multiple cutting grooves 20324 in the cut tube segment 20323, the strength of the cut tube segment 20323 can be reduced. Therefore, during the process of retrieving the cut tube segment 20323 into the bending adjustment tube, the cut tube segment 20323 can be easily bent to conform to the curved portion of the bending adjustment tube, thereby facilitating the retraction of the inner sheath 203 carrying the distal filter 205 into the bending adjustment tube. Optionally, the length of the cut tube segment 20323 is greater than or equal to 3 mm and less than or equal to 5 mm; the length of the proximal delivery tube 2033 is greater than or equal to 1200 mm and less than or equal to 1600 mm.

[0107] 14 to 16 , in one embodiment, the distal end of the cutting tube segment 20323 is connected to the proximal end of the spring tube segment 20321 .

[0108] Specifically, the distal fixing tube 2032 includes a connecting portion 20322 , and the distal end of the cutting tube segment 20323 and the proximal end of the spring tube segment 20321 can be connected via the connecting portion 20322 .

[0109] Referring to Figures 16, 18, and 21, in one embodiment, the distal filter 205 includes a second elastic metal skeleton 2051 and a second polymer membrane 2052. The second polymer membrane 2052 includes a second porous filter membrane 20521. The second porous filter membrane 20521 is connected to the second elastic metal skeleton 2051. The second porous filter membrane 20521 has a contracted state and an expanded state. The second elastic metal skeleton 2051 is used to support the second porous filter membrane 20521. In the expanded state, the second porous filter membrane 20521 is contracted from the proximal end to the distal end.

[0110] The second elastic metal skeleton 2051 is an elastic skeleton and can be elastically compressed to retract the distal filter 205 in a contracted state within the intermediate sheath 202. When the distal filter 205 is released from the intermediate sheath 202, the second elastic metal skeleton 2051 can elastically restore the distal filter 205 to an expanded state, thereby expanding the second porous filter membrane 20521. The material of the second elastic metal skeleton 2051 is, for example, at least one of a nickel-titanium alloy, an inconel alloy, or other metal materials.

[0111] When the second porous filter membrane 20521 is stretched by the second elastic metal skeleton 2051, i.e., in the expanded state, it contracts from the proximal end to the distal end, thereby forming an opening at the distal end of the distal filter 205, giving the overall shape of an umbrella or triangular pyramid. The second porous filter membrane 20521 has pores of a specific shape and area, which facilitate blood flow and filter embolic objects.

[0112] The distal filter 205 is fixed to the inner sheath 203 at both the distal end and the proximal end, and can be fixed by bonding, welding, hot melting, etc.

[0113] Preferably, the second porous filter membrane 20521 is covered on the outside of the second elastic metal skeleton 2051. In some cases, the second porous filter membrane 20521 can also be covered on the inside of the second elastic metal skeleton 2051.

[0114] Unlike existing pure metal braided stent filters, the distal filter 205 in this embodiment uses an elastic metal frame, and a polymer porous filter membrane is disposed on the elastic metal frame. Compared to pure metal braided stent filters, the pore size of the polymer porous filter membrane is more flexible and controllable, and the processing difficulty is lower. At the same time, when achieving the same strength performance requirements, the thickness of the polymer porous filter membrane is much lower than that of the pure metal braided stent (up to 1 / 10), so there is a smaller space effect during device delivery and recovery, making it easier to recover and transport.

[0115] Furthermore, due to the thinness and high strength of the polymer porous filter membrane, it is more easily able to filter large-sized thrombi, plaques, and other substances in actual use. Compared to pure metal braided stent filters, under the same filtering conditions, when filtering out larger embolic objects, the structure of the distal filter 205 of this embodiment is more easily retracted into the intermediate sheath 202, avoiding partial or complete re-sheathing. It also significantly reduces the pressure on the intermediate sheath 202, inner sheath 203, and left common carotid artery 12 during the recovery process, greatly improving product safety.

[0116] The second porous filter membrane 20521 is made of a polymer material and can be any one or more of PU, PET, TPU, PTFE, etc. The second porous filter membrane 20521 is distributed with pores of a certain pore size, a certain pore spacing, and a certain area. The pore size can be 80-160 μm, and the pore spacing is generally comparable to the pore size, 80-160 μm. The pore area cannot be too large, as this will affect the overall strength and filtration performance of the second porous filter membrane 20521. It cannot be too small, as this will affect the overall blood flow, leading to localized high blood pressure and excessive pressure differentials.

[0117] In one embodiment, a second developing ring (not shown) is sleeved on the outer periphery of the distal end of the second elastic metal skeleton 2041. The material of the second developing ring can be at least one of platinum, platinum tungsten or platinum iridium alloy.

[0118] Referring to Figures 15 to 17 , in one embodiment, the inner sheath 203 includes a tip tube 2031, which is a polymer tube and is connected to the distal end of a distal fixing tube 2032. The distal end of a second elastic metal skeleton 2051 is connected to the proximal end of a second porous filter membrane 20521 and supports the shape of the proximal end of the second porous filter membrane 20521. The distal end of the second porous filter membrane 20521 is connected to the tip tube 2031, and the second elastic metal skeleton 2051 is connected to the distal fixing tube 2032.

[0119] In this way, the second elastic metal skeleton 2051 supports the proximal end of the second porous filter membrane 20521, and the head end tube 2031 supports the distal end of the second porous filter membrane 20521, so that the second porous filter membrane 20521 presents a shape that gradually shrinks from the proximal end to the distal end when in the expanded state.

[0120] Since the second elastic metal skeleton 2051 is also connected to the distal fixed tube 2032, when the distal filter 205 needs to be recovered into the bending tube, the distal fixed tube 2032 can pull the second elastic metal skeleton 2051 to move proximally during the process of the inner sheath 203 moving proximally, so that the distal end of the second elastic metal skeleton 2051 enters the bending tube through elastic compression, and then the distal end of the second elastic metal skeleton 2051 simultaneously compresses the second porous filter membrane 20521 and pulls it into the bending tube.

[0121] The head end tube 2031 can be a polymer tube, such as any one or more of PU, PET, TPU, PTFE, Pebax, etc.; the inner diameter is greater than or equal to 0.2mm and less than or equal to 0.5mm; the outer diameter is greater than or equal to 0.4mm and less than or equal to 0.5mm; the length is greater than or equal to 30mm and less than or equal to 60mm.

[0122] With reference to Figures 15 to 17 , in one embodiment, the proximal end of the head tube 2031 is embedded in the spring tube segment 20321 and the connecting portion 20322 of the distal fixing tube 2032, while the distal end of the proximal delivery tube 2033 is embedded in the cut tube segment 20323 of the distal fixing tube 2032. Therefore, compared to the head tube 2031 and the proximal delivery tube 2033, the distal fixing tube 2032 has the largest inner and outer diameters. Optionally, the distal fixing tube 2032 has an inner diameter greater than or equal to 0.4 mm and less than or equal to 0.6 mm; an outer diameter greater than or equal to 0.5 mm and less than or equal to 1 mm; and a length greater than or equal to 10 mm and less than or equal to 20 mm.

[0123] Referring to Figure 16 , in one embodiment, the second polymer membrane 2052 includes a head cap 2053, which is connected to the distal end of the second porous filter membrane 20521. The head cap 2053 also wraps around the distal end of the head tube 2031. Thus, when assembling the second polymer membrane 2052 and the head tube 2031, the second polymer membrane 2052 can be covered with the distal end of the head tube 2031 via the head cap 2053. The proximal end of the second porous filter membrane 20521 is then connected to the proximal end of the second elastic metal skeleton 2051. Thus, the second porous filter membrane 20521 is supported by the proximal end of the second elastic metal skeleton 2051 and the distal end of the head tube 2031. The distal end of the distal filter 205 is connected to the distal end of the inner sheath 203 by a polymer material, eliminating the need for metal materials. This allows the distal end of the distal filter 205 and the distal end of the inner sheath 203 to be made of a relatively soft material, making them easy to bend and less likely to damage blood vessels. The distal end of the head cap 2053 and the distal end of the head tube 2031 can be connected by bonding, welding, or other methods.

[0124] Referring to Figures 16 to 21 , in one embodiment, the second elastic metal skeleton 2051 includes a second support ring 20511, a second support wire 20512, and a second fixing wire 20513. The proximal end of the second porous filter membrane 20521 is connected to the second support ring 20511, and the two are shaped to fit together. The second fixing wire 20513 is fixedly attached to the distal fixing tube 2032, with the proximal end of the second support wire 20512 connected to the second fixing wire 20513, and the distal end of the second support wire 20512 connected to the second support ring 20511.

[0125] The proximal end of the second porous filter membrane 20521 surrounds the circumference of the second support ring 20511 and is supported by the second support ring 20511 so that the proximal end of the second porous filter membrane 20521 maintains its shape.

[0126] Since the proximal filter 204 and the distal filter 205 are placed in different blood vessel locations during use, they also differ in size.

[0127] Optionally, the diameters of the second supporting ring 20511 , the second supporting wire 20512 , and the second fixing wire 20513 are greater than or equal to 0.05 mm and less than or equal to 0.2 mm.

[0128] The dimension of the second elastic metal skeleton 2051 along the length direction of the inner sheath tube 203 is greater than or equal to 30 mm and less than or equal to 60 mm.

[0129] In its natural state, the second support ring 20511 can be elliptical. Optionally, the major axis is greater than or equal to 4 mm and less than or equal to 10 mm, and the minor axis is greater than or equal to 3 mm and less than or equal to 6 mm. In some cases, the second support ring 20511 can also be circular in its natural state.

[0130] The second support ring 20511 can be a closed structure or an open ring. As shown in Figures 18 and 19, when the second support ring 20511 is an open ring, the two ends of the opening of the second support ring 20511 are respectively connected to the two second support wires 20512, thereby forming two connection points, namely connection point 20511A and connection point 20511B.

[0131] In the embodiment shown in Figures 18 and 19, there are two second support wires 20512. In other embodiments, the number of second support wires 20512 is not limited to two, and may be one, three, four, etc.

[0132] The second support wire 20512 and the axial end surface of the second support ring 20511 are arranged at an angle, and the angle between the two can be 60-120 degrees.

[0133] A second reference plane and a second projection plane are defined. The second reference plane is the plane defined by the central axis of the second support ring 20511 and the central axis of the second support wire 20512. The second projection plane is the plane perpendicular to the second reference plane and passing through the central axis of the second support ring 20511. Optionally, the projected length of the second support wire 20512 on the second projection plane is greater than or equal to 10 mm and less than or equal to 20 mm.

[0134] As shown in Figures 18 and 19, the second fixing wires 20513 are connected one-to-one with the second supporting wires 20512. The second fixing wires 20513 can extend in a straight line and be fixed closely to the inner sheath 203.

[0135] The second fixing wire 20513 may also be wound around the inner sheath 203. Optionally, the projected length of the second fixing wire 20513 on the second projection plane is greater than or equal to 15 mm and less than or equal to 25 mm.

[0136] Specifically, the second developing ring can be sleeved on the second supporting ring 20511, and both ends of the second developing ring are flush with the second supporting ring 20511 to maintain its stability.

[0137] In one embodiment, the thrombus filtering device further includes an operating assembly. The proximal ends of the outer sheath 201, the intermediate sheath 202, and the inner sheath 203 are each connected to the operating assembly. The operating assembly is used to control the movement of the outer sheath 201 relative to the intermediate sheath 202, the movement of the inner sheath 203 relative to the intermediate sheath 202, and the bending of the bend adjustment tube. The proximal end of the bend adjustment wire can be connected to the operating assembly.

[0138] In conjunction with Figures 2, 4 and 5, in one embodiment, the operating component includes a first handle 206, a sheath pushing knob 207, a second handle 208, a filter pushing knob 209, and a bending control knob 210. The first handle 206 is connected to the outer sheath 201 and is used to control the movement of the outer sheath 201 relative to the middle sheath 202. The second handle 208 is used for the operator to hold. The filter pushing knob 209 is used to control the movement of the inner sheath 203 relative to the middle sheath 202. The bending control knob 210 is connected to the proximal end of the bending wire and is used to control the bending of the bending tube. The various components of the operating component can be directly connected or indirectly connected through an intermediate component, as long as the movement and control functions of the various components can be met, and there is no restriction on this.

[0139] The specific structure of the operating assembly can also refer to other operating assemblies in the prior art, as long as it can meet the relative movement of the three tubes of the outer sheath tube 201, the middle sheath tube 202, and the inner sheath tube 203, and the bending of the bending adjustment tube of the middle sheath tube 202.

[0140] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0141] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

[0142] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0143] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A thrombus filtration device, characterized in that, The thrombus filtration device includes: an outer sheath tube, an intermediate sheath tube, a proximal filter, an inner sheath tube, and a distal filter; The intermediate sheath tube includes a push tube and a bending adjustment tube. The distal end of the push tube is connected to the proximal end of the bending adjustment tube. The proximal filter is connected to the push tube. The outer sheath tube is movably sleeved outside the intermediate sheath tube; The distal filter is connected to the distal end of the inner sheath tube. The inner sheath tube is movably inserted into the intermediate sheath tube; The inner sheath tube includes a proximal delivery tube and a distal fixing tube connected to each other. The distal fixing tube is a metal tube, and the distal fixing tube includes a spring tube section.

2. The thrombus filtration device according to claim 1, wherein, The distal fixing tube includes a cutting tube section, and the cutting tube section is provided with a plurality of cutting grooves arranged axially in sequence.

3. The thrombus filtration device according to claim 1, wherein The proximal filter includes a first elastic metal framework and a first polymer membrane. The first polymer membrane includes a first porous filter membrane. The first porous filter membrane covers the first elastic metal framework. The first porous filter membrane has a contracted state and an expanded state. The first porous filter membrane converges in the distal-to-proximal direction in the expanded state; And / or, the distal filter includes a second elastic metal framework and a second polymer membrane. The second polymer membrane includes a second porous filter membrane. The second porous filter membrane is connected to the second elastic metal framework. The second porous filter membrane has a contracted state and an expanded state. The second porous filter membrane converges in the proximal-to-distal direction in the expanded state.

4. The thrombus filtration device according to claim 3, characterized in that, The first elastic metal framework includes a first support ring, a first support wire, and a first fixing wire. The distal end of the first porous filter membrane is connected to the first support ring and their shapes are adapted. The first fixing wire is fixedly attached to the push tube. The proximal end of the first support wire is connected to the first fixing wire, and the distal end of the first support wire is connected to the first support ring.

5. The thrombus filtration device according to claim 3, characterized in that, The first polymer membrane further includes a support membrane, and the support membrane surrounds and adheres to the proximal end of the first porous filter membrane.

6. The thrombus filtration device according to claim 3, characterized in that, The first polymer membrane further includes an inner sleeve section, and the inner sleeve section is sleeved and adheres to the push tube. The proximal end of the first porous filter membrane is sleeved and adheres to the inner sleeve section.

7. The thrombus filtration device according to claim 3, wherein The first polymer membrane further includes an outer sleeve section, and the outer sleeve section is sleeved and adheres to the proximal end of the first porous filter membrane.

8. The thrombus filtration device according to claim 3, wherein The inner sheath tube includes a head tube, and the head tube is a polymer tube. The proximal end of the head tube is connected to the distal end of the distal fixing tube; The distal end of the second elastic metal framework is connected to the proximal end of the second porous filter membrane and supports the shape of the proximal end of the second porous filter membrane. The distal end of the second porous filter membrane is connected to the head tube. The second elastic metal framework is connected to the distal fixing tube.

9. The thrombus filtration device according to claim 8, wherein, The second polymer membrane includes a head cap, and the head cap is connected to the distal end of the second porous filter membrane. The head cap wraps the distal end of the head tube.

10. The thrombus filtration device according to claim 3, characterized in that, The second elastic metal framework includes a second support ring, second support wires and second fixing wires. The proximal end of the second porous filter membrane is connected to the second support ring and their shapes are adapted to each other; the second fixing wires are fixedly attached to the distal fixing tube, the proximal ends of the second support wires are connected to the second fixing wires, and the distal ends of the second support wires are connected to the second support ring.

11. The thrombus filtration device according to claim 1, characterized in that, The thrombus filtration device further includes a bending adjustment wire. The distal end of the bending adjustment wire is connected to the bending adjustment tube, and the bending adjustment wire passes through the bending adjustment tube and the pushing tube.

12. The thrombus filtration device according to claim 1, wherein, The most distal position of the proximal filter does not exceed the farthest distance that the outer sheath tube can be pushed, and the nearest position of the proximal end of the proximal filter is not closer than the nearest distance that the outer sheath tube can be retracted.

13. The thrombus filtration device according to claim 11, wherein, The bending adjustment tube includes a first tube and a second tube. The proximal end of the first tube is connected to the distal end of the pushing tube, the distal end of the first tube is connected to the proximal end of the second tube, the bending adjustment wire can drive the first tube and the second tube to bend in sequence. The first tube bends in a first direction, the second tube bends in a second direction, and the second direction is opposite to the first direction.

14. The thrombus filtration device according to claim 13, wherein, The distal end of the bending adjustment wire is connected to the second tube, and the bending adjustment wire passes through the second tube, the first tube and the pushing tube.

15. The thrombus filtration device according to claim 8, wherein The distal fixing tube further includes a connecting portion and a cutting tube section. The distal end of the cutting tube section is connected to the proximal end of the spring tube section through the connecting portion. The proximal end of the head end tube is embedded in the spring tube section and the connecting portion of the distal fixing tube, and the distal end of the proximal delivery tube is embedded in the cutting tube section of the distal fixing tube.

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