A woven vena cava filter

Abstract

The application discloses a woven type vena cava filter, which comprises a woven filter, and the woven filter is woven by a plurality of metal wires; the woven filter is sequentially formed with a fishing section, an abutting section and an opening section from a distal end to a proximal end; the metal wires of the abutting section are in a three-dimensional spiral shape, the three-dimensional spiral metal wires of the abutting section are overlapped and woven into a flat tubular structure, the abutting section is used for contacting with an inner wall of a blood vessel, so that the woven filter is fixed in the blood vessel; the metal wires of the fishing section are in a three-dimensional spiral shape, and the spiral radius of the three-dimensional spiral metal wires of the fishing section decreases in a distal end direction; the metal wires of the fishing section are formed with mesh holes, the mesh holes can allow blood flow and limit thrombus; the metal wires of the opening section are stranded into a plurality of metal bundles, and the metal bundles of the opening section are formed with openings, and the openings can allow the thrombus to pass. The application has better compliance and abutting property, can reduce damage to the blood vessel wall, prevents the filter from deviating, and has better developing effect.

Description

Technical Field

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

[0002] A vena cava filter (VCF) is a medical device implanted in the inferior vena cava (IVC) primarily used to prevent pulmonary embolism (PE) caused by the dislodgement of deep vein thrombosis (DVT) in the lower extremities. The VCF is typically inserted percutaneously into the inferior vena cava before venous thrombosis treatment to prevent large thrombi from entering the pulmonary circulation, thereby reducing the incidence of pulmonary embolism and preventing fatal pulmonary embolisms.

[0003] Currently, most vena cava filters on the market use a cutting-type skeleton for the retrieval part. These filters are generally large in size, have poor compliance with blood vessels, high pushing resistance, and require precise release positions. When released into curved blood vessels, they are prone to poor adhesion to the vessel wall, and when released into the vessel, they have a significant impact on the vessel wall. They are also more likely to cause damage to the blood vessel during filter retrieval. Secondly, the cutting-type vena cava filter is prone to positional displacement after release, causing the retrieval hook to adhere to the wall, making retrieval difficult. On the other hand, the current integrated cutting skeleton has poor imaging performance. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention provides a braided vena cava filter with better conformability and wall adhesion, which can reduce damage to the blood vessel wall, prevent filter displacement, and has better imaging effect.

[0005] The purpose of this invention is to provide a braided vena cava filter, comprising a braided filter made of several metal wires; the braided filter is formed sequentially from distal to proximal in the direction of a catching section, a wall-adhering section and an opening section;

[0006] The metal wires of the wall-adhering section are interlaced and woven into a straight tubular structure. The wall-adhering section is used to contact the inner wall of the blood vessel, thereby fixing the braided filter inside the blood vessel.

[0007] The fishing section is connected to the distal end of the wall-mounted section, and the radius of the fishing section decreases towards the distal end; a mesh is formed between the metal wires of the fishing section, which allows blood flow and restricts the passage of thrombi;

[0008] The opening segment is connected to the proximal end of the wall-attached segment. The metal wires of the opening segment are twisted into several metal bundles, and an opening is formed between the metal bundles of the opening segment, which allows the thrombus to pass through.

[0009] In a preferred embodiment, the braided filter further includes a proximal restraint ring and a distal restraint ring;

[0010] The proximal restraint ring includes a proximal inner ring and a proximal outer ring, with the proximal outer ring sleeved around the circumference of the proximal inner ring; the proximal end of the metal bundle is fixed between the proximal inner ring and the proximal outer ring.

[0011] The distal restraint ring includes a distal inner ring and a distal outer ring, with the distal outer ring sleeved around the distal inner ring in the circumferential direction; the distal end of the metal wire is fixed between the distal inner ring and the distal outer ring.

[0012] In a preferred embodiment, a support member is wound around the surface of the metal bundle of the opening segment;

[0013] The support is made of a developing material;

[0014] The support provides the metal bundle with an elastic force that extends radially from the proximal restraint ring.

[0015] As a preferred embodiment, it further includes a conveying sheath and a tightening wire; a tightening channel is formed inside the conveying sheath; the tightening wire passes through the conveying sheath, and both ends of the tightening wire extend from both ends of the tightening channel;

[0016] The proximal restraint ring is connected to the delivery sheath, and the distal restraint ring is connected to the distal end of the tightening wire;

[0017] By pushing and pulling the tightening yarn, the distal binding ring and the proximal binding ring are moved away from or closer to each other, allowing the braided filter to switch between a contracted state and an unfolded state.

[0018] In a preferred embodiment, the delivery sheath is provided with a distal fixing plate and a proximal fixing plate; the distal fixing plate is located at the distal end of the delivery sheath; the proximal fixing plate is located on the proximal side of the distal fixing plate; the distance between the distal fixing plate and the proximal fixing plate is l1.

[0019] The proximal restraint ring is disposed between the distal fixing plate and the proximal fixing plate, and the proximal inner ring is sleeved on the surface of the delivery sheath, so that the proximal restraint ring can slide along the axial direction of the delivery sheath between the distal fixing plate and the proximal fixing plate;

[0020] The woven filter has an unfolded state including a minimum unfolded state. When the woven filter is in the minimum unfolded state, the distance between the proximal binding ring and the distal binding ring is l2, where l2 = l1.

[0021] In a preferred embodiment, the distal inner ring has an inner ring cavity;

[0022] The end of the tightening wire is formed with a spherical head end, which engages with the inner cavity of the inner ring.

[0023] In a preferred embodiment, a plurality of sector-shaped blocks are formed on the distal inner ring, and an expansion channel is formed between the sector-shaped blocks, the expansion channel communicating with the inner cavity of the inner ring; an expansion cone surface is formed on the proximal end face of the sector-shaped blocks, the expansion cone surface being disposed towards the expansion channel;

[0024] The outer side of the distal fixing plate has a push cone surface. When the distal fixing plate approaches the distal inner ring, the push cone surface contacts the expansion cone surface. The expansion channel is opened by the push cone surface, allowing the distal fixing plate to be inserted into the inner cavity of the inner ring, so that the spherical head end of the tightening wire can be pulled out from the inner cavity of the inner ring.

[0025] In a preferred embodiment, the delivery sheath includes a body section and a release section; the release section is detachably connected to the distal end of the body section.

[0026] In a preferred embodiment, a first mating portion is formed circumferentially at the distal end of the body segment; a release device is connected to the proximal end of the release segment, the release device having a second mating portion, and the first mating portion and the second mating portion are adapted to each other.

[0027] In a preferred embodiment, the proximal end face of the release device is provided with a retrieval hook; the retrieval hook has a hook portion, and the hook portion of the retrieval hook is arranged toward the axis of the release device.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] Compared to commonly used cutting-type filters, the braided vena cava filter of this invention has a smaller compressed delivery volume, lower pushing force, and is easier to precisely deliver. Simultaneously, the braided structure allows for adaptive release in curved blood vessels, resulting in better fit. Furthermore, the braiding process of the vena cava filter is simpler than laser cutting, and the finer diameter of the braided filaments reduces damage to the vessel wall and lowers the risk of complications. Traditional braided filters are prone to displacement after release, affecting retrieval and thrombus retrieval efficiency. This invention's braided vena cava filter, by introducing a tensioning and limiting device, effectively prevents positional displacement, ensuring that the proximal opening of the filter completely covers the blood vessel, thus improving thrombus interception efficiency and optimizing retrieval convenience. The braided filter can be fitted with radiopaque fibers, giving the entire filter a radiopaque effect, making surgical observation easier. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the braided vena cava filter according to Embodiment 1 of the present invention;

[0031] Figure 2 This is a front view of the braided vena cava filter of Embodiment 1 of the present invention;

[0032] Figure 3This is a left view of the braided vena cava filter of Embodiment 1 of the present invention;

[0033] Figure 4 This is a front view of the braided filter of the braided vena cava filter according to Embodiment 1 of the present invention;

[0034] Figure 5 This is a schematic diagram of the proximal restraint ring of the braided vena cava filter according to Embodiment 1 of the present invention;

[0035] Figure 6 This is a schematic diagram of the internal structure of the proximal restraint ring of the braided vena cava filter according to Embodiment 1 of the present invention;

[0036] Figure 7 This is a schematic diagram of the connection of the distal restraint ring of the braided vena cava filter according to Embodiment 1 of the present invention;

[0037] Figure 8 This is a schematic diagram of the distal inner ring of the braided vena cava filter according to Embodiment 1 of the present invention;

[0038] Figure 9 This is a schematic diagram of the braided vena cava filter according to Embodiment 2 of the present invention;

[0039] Figure 10 This is a schematic diagram of the braided vena cava filter according to Embodiment 3 of the present invention;

[0040] Figure 11 This is a schematic diagram of the disengagement device of the braided vena cava filter according to Embodiment 3 of the present invention.

[0041] In the diagram: 10. Woven filter; 11. Fishing section; 12. Wall-mounted section; 13. Opening section; 20. Conveying sheath; 21. Body section; 211. First mating part; 22. Proximal fixing plate; 23. Release section; 24. Distal fixing plate; 241. Propulsion cone surface; 30. Tightening wire; 31. Spherical head end; 40. Release device; 41. Recovery hook; 42. Second mating part; 50. Proximal restraint ring; 51. Proximal outer ring; 52. Proximal inner ring; 60. Distal restraint ring; 61. Distal outer ring; 62. Distal inner ring; 621. Inner ring cavity; 622. Fan-shaped block; 623. Expansion channel; 624. Expansion cone surface; 70. Support member. Detailed Implementation

[0042] The invention will now be further described with reference to the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments. Unless otherwise specified, the materials and equipment used in this embodiment are commercially available. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0043] In the description of this application, it should be understood that the terms "upper," "lower," "front," "rear," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In the description of this application, "a plurality of" means two or more, unless otherwise precisely specified.

[0044] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "connected," "linked," and "connected" should be interpreted broadly. For example, they can refer to a fixed connection, a connection through an intermediary, or a connection within two elements or an interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0045] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product, or apparatus.

[0046] Example 1:

[0047] refer to Figure 1-8 As shown, this embodiment provides a braided vena cava filter, including a braided filter 10, which is made of several metal wires; the metal wires are preferably nickel-titanium wires, wherein some wires can be replaced with platinum-tungsten wires with imaging function, or the whole filter can use DFT wire with imaging function to increase imaging performance, and the metal wires are preferably round wires.

[0048] The braided filter 10 is formed sequentially from distal to proximal end into a catching section 11, a wall-adhering section 12, and an opening section 13. The metal wires of the catching section 11 and the wall-adhering section 12 of the braided filter 10 are both continuous three-dimensional spirals, and several metal wires are interwoven in the catching section 11 and the wall-adhering section 12 to form a cage-like structure. The metal wires of the proximal opening section 13 of the braided filter 10 are divided into several strands, and the openings between the strands allow thrombi to enter the filter and be blocked.

[0049] Specifically, the metal wire of the wall-attaching segment 12 is in a three-dimensional spiral shape, and the spiral radius of the three-dimensional spiral metal wire of the wall-attaching segment 12 is a constant. That is, several metal wires overlap and weave the wall-attaching segment 12 into a straight tubular structure. The wall-attaching segment 12 with the straight tubular structure can fully contact the inner wall of the blood vessel, thereby fixing the braided filter 10 in the blood vessel.

[0050] The fishing section 11 is connected to the distal end of the wall-adhering section 12. The metal wires of the wall-adhering section 12 are in a three-dimensional spiral shape. The spiral radius of the three-dimensional spiral metal wires of the fishing section 11 decreases towards the distal end. That is, several metal wires overlap and weave the fishing section 11 into a cone-shaped, umbrella-shaped, hemispherical, or semi-olive-shaped structure. Mesh holes are formed between the metal wires of the fishing section 11. The mesh holes allow blood flow and restrict the passage of thrombi, thus blocking the thrombi.

[0051] The opening segment 13 is connected to the other end of the wall-adhering segment 12. The opening segment 13 is located near the proximal end of the wall-adhering segment 12. The metal wires of the opening segment 13 are stranded into several metal bundles. Preferably, there are three or more metal bundles. The several metal bundles form a structure similar to a multi-faceted pyramid. An opening is formed between the metal bundles of the opening segment 13, and the opening allows the thrombus to pass through.

[0052] Based on the above structure, this embodiment uses a braided filter 10 made of several metal wires. The braided filter 10 has a smaller diameter when retracted into the sheath, making it easier to push into place and allowing release into curved blood vessels. When the blood vessel is compressed or bent, its metal wire braided structure can elastically deform to alleviate friction and displacement between the vena cava filter and the vessel wall, thereby reducing damage to the vessel wall. A straight tubular wall-adhering section 12 is designed between the retrieval section 11 and the opening section 13. The wall-adhering section 12 can also elastically deform to better conform to the inner wall of the blood vessel, increasing the contact area between the braided filter 10 and the vessel wall, ensuring good adhesion of the filter within the blood vessel without gaps, and preventing positional displacement of the filter, thus not affecting retrieval. By replacing some of the wires in the braided filter with platinum-tungsten wire with imaging capabilities, or using DFT wire with imaging capabilities as the entire filter, imaging properties are increased, giving the entire filter imaging effect, making surgical observation easier.

[0053] Furthermore, the woven filter 10 is provided with a proximal binding ring 50 and a distal binding ring 60 at both ends. The proximal end of the opening section 13 of the woven filter 10 is bound by the proximal binding ring 50, and the distal end of the catching section 11 of the woven filter 10 is bound by the distal binding ring 60.

[0054] The proximal restraint ring 50 is composed of a proximal inner ring 52 and a proximal outer ring 51 that are nested together. The proximal outer ring 51 is sleeved around the proximal inner ring 52. A proximal restraint gap is formed between the proximal inner ring 52 and the proximal outer ring 51. The proximal end of the metal bundle of the opening segment 13 is fixed in the proximal restraint gap by bonding or welding.

[0055] The distal restraint ring 60 includes a distal inner ring 62 and a distal outer ring 61, wherein the distal outer ring 61 is sleeved on the outer periphery of the distal inner ring 62; a distal restraint gap is formed between the distal inner ring 62 and the distal outer ring 61, and the distal restraint gap restrains the distal end of the metal wire of the fishing section 11, which is fixed by bonding or welding.

[0056] In this embodiment, the braided filter 10 is fixed at both ends by setting a proximal restraint ring 50 and a distal restraint ring 60, which prevents the metal wire from unraveling due to blood flow impact or vascular movement after the filter is released or implanted for a long time, thus maintaining the overall structural integrity of the filter. Since both the proximal restraint ring 50 and the distal restraint ring 60 are composed of interlocking inner and outer rings, a restraint gap is formed between the inner and outer rings, which can smoothly gather the end of the metal wire, preventing the free wire tip from piercing the vascular intima and reducing the risk of perforation or chronic inflammation.

[0057] A support member 70 is wound around the surface of the metal bundle in the opening segment 13. The support member 70 can be made of platinum-tungsten or other radiopaque materials to provide radiopaque properties. The support member 70 binds the stranded metal wires of the opening segment 13 and provides a certain supporting force, allowing the braided filter 10 to maintain its shape after release and expansion, so that thrombi can enter the filter through the opening and be captured. Preferably, the support member 70 is elastic, providing the metal bundle with an elastic force extending radially around the proximal binding ring 50, so that the braided filter 10 has radial expansion elasticity and better wall adhesion.

[0058] Furthermore, the braided vena cava filter of this embodiment also includes a delivery sheath 20 and a tightening wire 30; the delivery sheath 20 is a slender tubular structure with a tightening channel formed inside. The tightening wire 30 is a nickel-titanium wire or a stainless steel wire, which can be threaded through the delivery sheath 20, and the two ends of the tightening wire 30 extend from the two ends of the tightening channel, respectively.

[0059] The proximal binding ring 50 is connected to the delivery sheath 20, and the distal binding ring 60 is connected to the distal end of the tightening wire 30; by pushing and pulling the tightening wire 30, the distal binding ring 60 and the proximal binding ring 50 are moved away from or closer to each other, thereby allowing the braided filter 10 to switch between a contracted state and an unfolded state.

[0060] The delivery sheath 20 is provided with a distal fixing plate 24 and a proximal fixing plate 22; the distal fixing plate 24 is located at the distal end of the delivery sheath 20; the proximal fixing plate 22 is located on the proximal side of the distal fixing plate 24; the distance between the distal fixing plate 24 and the proximal fixing plate 22 is l1.

[0061] The proximal restraint ring 50 is disposed between the distal fixing plate 24 and the proximal fixing plate 22, and the proximal inner ring 52 is sleeved on the surface of the delivery sheath 20, so that the proximal restraint ring 50 can slide along the axial direction of the delivery sheath 20 between the distal fixing plate 24 and the proximal fixing plate 22.

[0062] The braided filter 10 has a minimum unfolded state and a maximum unfolded state. When the braided filter 10 is in the minimum unfolded state, the distance between the proximal binding ring 50 and the distal binding ring 60 is l2, where l2 = l1.

[0063] The proximal restraint ring 50 is limited by the distal fixation plate 24 and the proximal fixation plate 22. When the position of the distal restraint ring 60 is fixed, the greater the distance between the proximal restraint ring 50 and the distal restraint ring 60, that is, the larger the value of l2, the more axially the braided filter 10 is stretched, and the smaller its radial expansion. When the proximal restraint ring 50 gradually moves closer to the distal restraint ring 60, that is, when the value of l2 gradually decreases, the braided filter 10 is axially compressed, and the radial synchronous expansion of the catching section 11, the wall-adhering section 12 and the opening section 13 is increased. The radial expansion of the braided filter 10 is greater, so that after the braided filter 10 is released into the blood vessel, its state can be adaptively and passively adjusted between the minimum expansion state and the maximum expansion state with the movement of the blood vessel, always maintaining stable contact with the blood vessel wall and providing better wall-adhering ability.

[0064] In this embodiment, the distal inner ring 62 has an inner ring cavity 621; one end of the inner ring cavity 621 can be a closed structure, and the other end forms a plurality of fan-shaped blocks 622, an expansion channel 623 is formed between the fan-shaped blocks 622, and the expansion channel 623 communicates with the inner ring cavity 621; an expansion cone surface 624 is formed on the proximal end face of the fan-shaped block 622, and the expansion cone surface 624 is disposed toward the expansion channel 623.

[0065] The tightening wire 30 has a spherical head end 31 at its end, which can be engaged within the inner ring cavity 621.

[0066] The distal fixing plate 24 has a push cone surface 241 formed on its outer side. When the distal fixing plate 24 approaches the distal inner ring 62, the push cone surface 241 contacts the expansion cone surface 624. The expansion channel 623 is opened by the push cone surface 241, so that the distal fixing plate 24 is inserted into the inner ring cavity 621, and the spherical head end 31 of the tightening wire 30 can be pulled out from the inner ring cavity 621.

[0067] Initially, the spherical tip 31 of the tightening wire 30 is locked in the inner ring cavity 621 of the distal restraint ring 60. After the braided filter 10 is released in the blood vessel, the delivery sheath 20 is pushed so that the distal fixing plate 24 of the delivery sheath 20 is pushed into the expansion cone surface 624, opening the expansion channel 623 and pulling the spherical tip 31 of the tightening wire 30 out of the inner ring cavity 621. The tightening wire 30 and its tip are withdrawn along the tightening channel of the delivery sheath 20, and the distal fixing plate 24 of the delivery sheath 20 remains in the inner ring cavity 621. Together with the proximal fixing plate 22, the distance between the distal restraint ring 60 and the proximal restraint ring 50 is limited within a certain range, so that the braided filter 10 maintains its expanded shape and will not be deformed by the blood flow.

[0068] The following provides a method of using the braided vena cava filter of this embodiment:

[0069] When in use, blood flows from the proximal end to the distal end of the blood vessel.

[0070] In this embodiment, the braided vena cava filter is housed in another delivery catheter. Before delivery, the spherical end 31 of the tightening wire 30 is engaged in the inner ring cavity 621 of the distal restraint ring 60. By pulling the tightening wire 30, the braided filter 10 can move within a certain range.

[0071] The delivery sheath 20 and the tightening wire 30 are pushed forward together through the delivery conduit. The tightening wire 30 drives the braided filter 10 (as well as the proximal restraint ring 50 and the distal restraint ring 60) to be pushed together through the spherical head end 31.

[0072] Based on the angiography results, select a suitable blood vessel location to release the braided filter 10. After release, the straight tubular wall-adhering section 12 of the braided filter 10 adheres to the blood vessel wall, fixing the entire braided filter 10 in place. Depending on the release status, adjust by appropriately pulling back the tightening wire 30 to ensure that the straight wall-adhering section 12 adheres better to the blood vessel wall.

[0073] After confirming that the braided filter 10 has been released, fix the tightening wire 30 to ensure that the position of the braided filter 10 remains unchanged, push the delivery sheath 20 forward, and the distal fixing plate 24 of the delivery sheath 20 will push into the expansion cone surface 624 of the distal restraint ring 60, causing the fan-shaped block 622 to open outward and opening the expansion channel 623. The spherical head end 31 of the tightening wire 30 will be pulled out from the inner ring cavity 621 of the distal restraint ring 60 towards the proximal end and removed from the body along the inside of the delivery sheath 20. The delivery sheath 20 will continue to be pushed forward, pushing the distal fixing plate 24 of the delivery sheath 20 into the inner ring cavity 621 of the distal restraint ring 60. The fan-shaped block 622 will reset under the action of elastic force and lock the distal fixing plate 24 in place. At the same time, the proximal fixing plate 22 of the delivery sheath 20 will limit the position of the proximal restraint ring 50, and together with the distal fixing plate 24 of the delivery sheath 20, the braided filter 10 will remain in an expanded state in the blood vessel.

[0074] After the procedure, pull back the delivery sheath 20, and the entire filter is removed from the delivery catheter.

[0075] Example 2:

[0076] refer to Figure 9 As shown, this embodiment provides a braided vena cava filter based on embodiment 1. The braided vena cava filter in this embodiment is a detachable vena cava filter.

[0077] The delivery sheath 20 is divided into two interconnected sections, namely the body section 21 and the release section 23; wherein the end of the release section 23 is detachably connected to the distal end of the body section 21.

[0078] Specifically, a first mating part 211 is formed circumferentially at the distal end of the body segment 21. In this embodiment, the first mating part 211 is an external thread. A release device 40 is connected to the proximal end of the release segment 23. The release device 40 is fixed to the proximal end of the release segment 23 of the delivery sheath 20 by bonding or welding. The release device 40 has a second mating part 42. In this embodiment, the second mating part 42 is an internal thread. The first mating part 211 and the second mating part 42 are adapted to each other, so that the body segment 21 and the release segment 23 are detachably connected together by thread engagement.

[0079] After the procedure, the body section 21 of the delivery sheath 20 is rotated to separate it from the release section 23, leaving the braided filter 10, the release section 23 of the delivery sheath 20, the release device 40, the proximal restraint ring 50 and the distal restraint ring 60 in the blood vessel, while the rest are removed.

[0080] Example 3:

[0081] refer to Figure 10-11 As shown, this embodiment provides a braided vena cava filter based on embodiment 2. The braided vena cava filter in this embodiment is a retrievable and detachable vena cava filter.

[0082] The proximal end face of the release device 40 is provided with a retrieval hook 41; the retrieval hook 41 has a hook portion, and the hook portion of the retrieval hook 41 is arranged toward the axis of the release device 40.

[0083] After the braided filter 10 is released, it can be retrieved by hooking the retrieval hook 41 using a specialized retrieval device. By using the braided filter 10 as an anchor point for the retrieval hook 41, the interventional instruments (such as snares) can be stably grasped, thus improving the success rate of retrieval.

[0084] The braided vena cava filter of this invention has significant advantages over commonly used cutting filters: its compressed delivery volume is smaller, the pushing force is lower, and it is easier to accurately deliver the filter into place; at the same time, the braided filter 10 can be adaptively released in curved blood vessels, resulting in better fit. Furthermore, the braiding process is simpler than laser cutting, and because the braided filaments are thinner, it reduces damage to the vessel wall and lowers the risk of complications. However, traditional braided filters are prone to displacement after release, affecting retrieval and thrombus retrieval efficiency. The braided vena cava filter of this invention introduces a tensioning and limiting device formed by the synergistic action of the delivery sheath 20, tightening wire 30, proximal restraint ring 50, and distal restraint ring 60, effectively preventing positional displacement and ensuring that the proximal opening segment 13 of the filter completely covers the blood vessel, thus improving thrombus interception efficiency and optimizing retrieval convenience.

[0085] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A braided vena cava filter, characterized in that, The filter includes a woven filter, which is made of several metal wires woven together; the woven filter is formed sequentially from the distal end to the proximal end into a fishing section, a wall-adhering section and an open section. The metal wires of the wall-adhering section are interlaced and woven into a straight tubular structure. The wall-adhering section is used to contact the inner wall of the blood vessel, thereby fixing the braided filter inside the blood vessel. The fishing section is connected to the distal end of the wall-mounted section, and the radius of the fishing section decreases towards the distal end; a mesh is formed between the metal wires of the fishing section, which allows blood flow and restricts the passage of thrombi; The opening segment is connected to the proximal end of the wall-attached segment. The metal wires of the opening segment are twisted into several metal bundles, and an opening is formed between the metal bundles of the opening segment, which allows thrombi to pass through. The braided filter also includes a proximal restraint ring and a distal restraint ring; The proximal restraint ring includes a proximal inner ring and a proximal outer ring, with the proximal outer ring sleeved around the circumference of the proximal inner ring; the proximal end of the metal bundle is fixed between the proximal inner ring and the proximal outer ring. The distal restraint ring includes a distal inner ring and a distal outer ring, with the distal outer ring sleeved around the distal inner ring in the circumferential direction; the distal end of the metal wire is fixed between the distal inner ring and the distal outer ring; It also includes a conveying sheath and a tightening wire; a tightening channel is formed inside the conveying sheath; the tightening wire passes through the conveying sheath, and both ends of the tightening wire extend out from both ends of the tightening channel; The proximal restraint ring is connected to the delivery sheath, and the distal restraint ring is connected to the distal end of the tightening wire; By pushing and pulling the tightening wire, the distal binding ring and the proximal binding ring are moved away from or closer to each other, so that the braided filter switches between a contracted state and an unfolded state. The delivery sheath is provided with a distal fixing plate and a proximal fixing plate; the distal fixing plate is located at the distal end of the delivery sheath; the proximal fixing plate is located on one side of the proximal end of the distal fixing plate; the distance between the distal fixing plate and the proximal fixing plate is l1; The proximal restraint ring is disposed between the distal fixing plate and the proximal fixing plate, and the proximal inner ring is sleeved on the surface of the delivery sheath, so that the proximal restraint ring can slide along the axial direction of the delivery sheath between the distal fixing plate and the proximal fixing plate; The woven filter has an unfolded state including a minimum unfolded state. When the woven filter is in the minimum unfolded state, the distance between the proximal binding ring and the distal binding ring is l2, where l2 = l1.

2. The braided vena cava filter according to claim 1, characterized in that, The metal bundle surface of the opening section is wrapped with a support member; The support is made of a developing material; The support provides the metal bundle with an elastic force that extends radially from the proximal restraint ring.

3. A braided vena cava filter according to claim 1, characterized in that, The distal inner ring has an inner ring cavity; The end of the tightening wire is formed with a spherical head end, which engages with the inner cavity of the inner ring.

4. A braided vena cava filter according to claim 3, characterized in that, A plurality of fan-shaped blocks are formed on the distal inner ring, and an expansion channel is formed between the fan-shaped blocks. The expansion channel communicates with the inner cavity of the inner ring. An expansion cone surface is formed on the proximal end face of the fan-shaped block, and the expansion cone surface is oriented toward the expansion channel. The outer side of the distal fixing plate has a push cone surface. When the distal fixing plate approaches the distal inner ring, the push cone surface contacts the expansion cone surface. The expansion channel is opened by the push cone surface, allowing the distal fixing plate to be inserted into the inner cavity of the inner ring, so that the spherical head end of the tightening wire can be pulled out from the inner cavity of the inner ring.

5. A braided vena cava filter according to claim 1, characterized in that, The delivery sheath includes a body section and a release section; the release section is detachably connected to the distal end of the body section.

6. A braided vena cava filter according to claim 5, characterized in that, A first mating portion is formed circumferentially at the distal end of the body segment; a release device is connected to the proximal end of the release segment, and the release device has a second mating portion, wherein the first mating portion and the second mating portion are adapted to each other.

7. A braided vena cava filter according to claim 6, characterized in that, The proximal end face of the release device is provided with a retrieval hook; the retrieval hook has a hook portion, and the hook portion of the retrieval hook is arranged toward the axis of the release device.

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