Vena cava filter

Abstract

The embodiment of the present specification provides a vena cava filter, comprising: a stent part having a telescopic state, being in contact with a vena cava wall after being unfolded, and being formed with a hollow channel; a filter part being arranged in the hollow channel, one end of the filter part being in a radial structure and being connected with the stent part, the other end of the filter part being in a converging state and being suitable for collecting embolic materials; and the filter part comprising: a degradable structure and a non-degradable coating layer coated on the degradable structure, and the degradable structure being suitable for being degraded after the non-degradable coating layer is removed. By using the above scheme, the transformation process of the vena cava filter can be controlled, and the embolic materials in the vena cava wall can be more effectively treated.

Description

Technical Field

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

[0002] Pulmonary embolism (PE) is a pathological and clinical condition in which a blood clot remains in the pulmonary artery and obstructs the flow of blood to other parts of the lungs. It is the third most common cardiovascular disease after coronary heart disease and stroke.

[0003] Currently, traditional treatment methods mainly include systemic anticoagulation therapy, local thrombolysis, and thrombectomy. However, for patients with contraindications to anticoagulation, bleeding complications during anticoagulation, or recurrent thrombotic disorders, an inferior vena cava filter (IVCF) is needed to prevent pulmonary embolism caused by embolus dislodgement. The earliest permanent IVCFs were left in the body for a long time, which easily caused complications such as vena cava obstruction, filter breakage, displacement, and recurrent deep vein thrombosis, and required lifelong medication.

[0004] Currently, retrievable IVCFs are widely used. However, after two weeks of implantation, some of the retrievable IVCF filters are covered by the vascular endothelium, resulting in a short retrieval window, difficulty in retrieval, and a low retrieval rate. This means that the risk of venous thromboembolism or contraindications to anticoagulation in many patients is not completely eliminated, forcing them to prolong the filter retention time. Once the time window is exceeded, it becomes difficult to remove, leading to the problem of permanent filters.

[0005] In recent years, some convertible filters have emerged. After being implanted in the body for a period of time, they can filter blood clots. As some materials degrade, the filter deforms and transforms into a normal vascular support structure, at which point it supports the blood vessel, blood flow is restored, the risk of secondary removal is avoided, and the probability of complications is effectively reduced.

[0006] However, existing bioconvertible filters still have many shortcomings. For example, the conversion process of vena cava filters is uncontrollable. When the biodegradable switch is triggered prematurely, the filter fails prematurely and cannot perform its filtering function. Especially for patients who are in a hypercoagulable state, at high risk of PE, or have thrombotic disorders, a longer period of filter protection is required. Summary of the Invention

[0007] In view of this, embodiments of this specification provide a vena cava filter that can control the conversion process of the vena cava filter and more effectively treat emboli in the vena cava wall.

[0008] First, this specification provides an embodiment of a vena cava filter, comprising:

[0009] The support section has a telescopic state, and after unfolding, it contacts the cavity wall and forms a hollow channel;

[0010] A filter section is disposed within the hollow channel. One end of the filter section has a radial structure and is connected to the support section, while the other end is in a converged state, suitable for collecting emboli. The filter section includes a biodegradable structure and a non-biodegradable coating applied to the biodegradable structure. The biodegradable structure is adapted to degrade after the non-biodegradable coating is removed.

[0011] Optionally, the support portion includes: multiple expansion units, which are coupled together to form a ring structure.

[0012] Optionally, the expansion unit includes multiple expansion members, which are arranged in a circumferential array.

[0013] Optionally, the expansion unit is a concave expansion structure, and adjacent expansion members along the axial direction share the same end, while adjacent expansion members along the circumferential direction are fixedly connected.

[0014] Optionally, the concave tautology structure includes:

[0015] The first and second arc-shaped components are set relative to each other;

[0016] A first bent member and a second bent member are disposed on both sides of the first arc-shaped member and the second arc-shaped member, respectively, and are bent toward each other; and

[0017] The protruding ends are provided on both sides of the first bent member and the second bent member.

[0018] Optionally, the expansion unit is a tension-torsion expansion structure, and the expansion members adjacent along the axial direction and the expansion members adjacent along the circumferential direction are fixedly connected.

[0019] Optionally, the tension-torsion type expansion structure includes:

[0020] Ring-shaped component;

[0021] And a plurality of linear members distributed along the outer side of the annular member, and each adjacent expansion unit is fixedly connected by adjacent linear members.

[0022] Optionally, the expansion unit is an outwardly convex expansion structure, and adjacent expansion members are fixedly connected along the axial and circumferential directions.

[0023] Optionally, the convex expansion structure includes:

[0024] A first convex member and a second convex member are arranged opposite each other along the axial direction;

[0025] A first concave part and a second concave part are arranged opposite each other in the circumferential direction;

[0026] Furthermore, adjacent expansion units are fixedly connected axially via adjacent first concave and second concave members, respectively; and circumferentially via adjacent first convex and second convex members, respectively.

[0027] Optionally, the expansion unit is a rotary expansion structure, and adjacent expansion members are fixedly connected along the axial and circumferential directions.

[0028] Optionally, the rotary expansion structure includes a first shank and a second shank arranged in an alternating manner, and teeth disposed at both ends of the first shank and the second shank and arranged in a centrally symmetrical manner;

[0029] Furthermore, adjacent expansion units are fixedly connected axially via adjacent teeth connected to the second shank; and circumferentially via adjacent teeth connected to the first shank.

[0030] Optionally, the support portion further includes:

[0031] The groove structure is provided on the side of each expansion unit near the wall of the lumen. The groove structure arranged along the central axis of the vena cava filter is perpendicular to the central axis, and the groove structure arranged in the direction perpendicular to the central axis is parallel to the central axis. The groove structures in the two directions are orthogonally arranged.

[0032] Optionally, the groove structure is one or more of the following: a straight line, a cross, or a cross.

[0033] Optionally, the stent portion further includes a drug-carrying structure disposed on the side of each expansion unit away from the cavity wall, suitable for accommodating thrombolytic agents.

[0034] Optionally, the stent portion further includes an encapsulation layer adapted to be coated on the drug-loaded structure and used to release the thrombolytic agent after degradation to dissolve the embolus in the lumen.

[0035] Optionally, the filter section includes:

[0036] The filtration unit includes multiple filtration structures, one end of each filtration structure is connected to the support portion, and is adapted to collect the embolus, and each filtration structure is coated with the non-degradable coating.

[0037] A constraint unit is connected to the other end of each filter structure to form the aggregated state, and the constraint unit is coated with the non-degradable coating.

[0038] Optionally, the filter structure is a multi-layered radial structure.

[0039] Optionally, the filtration structure includes a plurality of first filter elements, the plurality of first filter elements having equal or unequal lengths and being staggered to form the multi-layer radial structure.

[0040] Optionally, the filter structure includes a plurality of second filter elements, the plurality of second filter elements having equal or unequal lengths, interwoven to form the multi-layer radial structure.

[0041] Optionally, the filtering unit and the constraint unit are made of shape memory material.

[0042] Optionally, the support portion is made of a biodegradable or non-biodegradable metal material.

[0043] Using the vena cava filter provided in the embodiments of this specification, the stent portion, after unfolding, can contact the lumen wall and form a hollow channel. The filter portion can be disposed within the hollow channel. Since one end of the filter portion is in a converged state, it can collect emboli in the lumen and contain them within the hollow channel. Moreover, since the filter portion includes a biodegradable structure and a non-biodegradable coating applied to the biodegradable structure, the filter portion will not be degraded during the collection of emboli, thereby enabling continuous collection of emboli and preventing their leakage. By removing the non-biodegradable coating, the biodegradable structure can be exposed, and the biodegradable structure can be degraded, thereby controlling the conversion process of the vena cava filter.

[0044] Furthermore, the support unit may include multiple expansion units, which are coupled and connected to each other to form a ring-shaped support unit. When the support unit is fully deployed, on the one hand, each expansion unit can directly contact the cavity wall and play a supporting role; on the other hand, the ring-shaped structure formed between each expansion unit has a hollow channel, which plays a role in accommodating the embolus, avoiding damage to the embolus, and thus can remove the embolus in one go, improving the treatment efficiency.

[0045] Furthermore, the expansion unit can include multiple expansion members. By circumferentially distributing the expansion members in an array, expansion units with different structures can be obtained, thereby forming a support part with a corresponding structure. This allows it to adapt to different luminal walls, especially some luminal walls with more tortuous shapes, enhancing the universality of the vena cava filter.

[0046] Furthermore, by making the concave expansion structure include a first arc-shaped member and a second arc-shaped member arranged opposite to each other, it is possible to achieve smooth contact with the cavity wall when the support part is fully extended, preventing puncture or scratching of the cavity wall; and the first bending member and the second bending member arranged on both sides of the first arc-shaped member and the second arc-shaped member, arranged opposite to each other and bent in opposite directions, can provide support stress for the support part.

[0047] Furthermore, by providing a groove structure on the side of the expansion unit near the cavity wall, the friction between it and the cavity wall can be increased, and the inner wall of the cavity can fully contact the groove structure. This can prevent the support part from moving axially and rotating along the central axis, effectively improving the support rigidity of the support part, reducing the risk of tilting and displacement, and enabling the support part to maintain a stable shape in the cavity, thereby improving the removal effect of the embolus.

[0048] Furthermore, by setting a drug-loaded structure on the side of the expansion unit away from the cavity wall, since the inside of the drug-loaded structure can accommodate thrombolytic agents, and the thrombolytic agents can dissolve emboli, the large emboli can be dissolved into smaller embolic blocks, which are easier to remove, thereby reducing the probability of embolism.

[0049] Furthermore, by coating the drug-loaded structure with an encapsulation layer, it is possible to ensure that when the vena cava filter reaches the embolus, the encapsulation layer degrades and releases a thrombolytic agent to dissolve the embolus in the lumen, thereby achieving the best thrombectomy effect. This allows larger emboli to be dissolved into smaller embolic fragments, making them easier to remove and reducing the probability of embolism.

[0050] Furthermore, the filtration section may include a filtration unit and a constraint unit. On one hand, the filtration unit may include multiple filtration structures, one end of each filtration structure being connected to the support section, and the other end being connected to the constraint unit to form a convergent state for collecting emboli. The constraint unit and the multiple filtration structures are coated with a non-degradable coating, thereby enabling continuous collection of the emboli and preventing the emboli from flowing out. On the other hand, after the non-degradable coating is removed, each filtration structure and constraint unit can be degraded, thereby enabling control of the conversion process of the vena cava filter.

[0051] Furthermore, by setting the filter structure to a multi-layered radial structure, the resulting filter structure has a lower density. While ensuring the smooth flow of fluid in the cavity, it can improve the capture effect of emboli and prevent emboli from flowing to other places, thereby reducing the probability of blockage.

[0052] Furthermore, the filter structure includes multiple second filter elements of equal or unequal length, which are interwoven to form the multi-layered radial structure. The weaving method is simple and can improve the weaving efficiency of the filter structure.

[0053] Furthermore, the stent portion can be made of a non-degradable metal material, which makes the stent portion flexible, improving the flexibility of the vena cava filter in specially shaped lumens and reducing damage to the lumen wall; or the stent portion can be made of a degradable metal material, which enables the degradation of the entire structure of the vena cava filter, eliminating the need for secondary removal and reducing the probability of complications. Attached Figure Description

[0054] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0055] Figure 1 This is a schematic diagram of the structure of a vena cava filter as described in the embodiments of this specification;

[0056] Figure 2a This is a schematic diagram of the structure of a bracket portion in one of the embodiments of this specification;

[0057] Figure 2b This is a schematic diagram showing the positional distribution of a drug-loaded structure on the support portion in one of the embodiments of this specification;

[0058] Figure 3a This is a schematic diagram of another support portion in an embodiment of this specification;

[0059] Figure 3b for Figure 3a A partial structural diagram of the central support section;

[0060] Figure 4a This is a schematic diagram of another type of support structure in the embodiments of this specification;

[0061] Figure 4b for Figure 4a A partial structural diagram of the central support section;

[0062] Figure 5a This is a schematic diagram of another support portion in an embodiment of this specification;

[0063] Figure 5b for Figure 5a A partial structural diagram of the central support section;

[0064] Figure 6 This is a schematic diagram of the structure of a filter section in one of the embodiments of this specification;

[0065] Figure 7a This is a schematic diagram of another vena cava filter in the embodiments of this specification;

[0066] Figure 7b A side view of the 7a vena cava filter;

[0067] Figures 8 to 10 This is a schematic diagram illustrating the working process of a vena cava filter in a blood vessel, as described in the embodiments of this specification. Detailed Implementation

[0068] As described in the background section, the conversion process of existing vena cava filters is uncontrollable. When the biodegradable switch is triggered prematurely, the filter fails prematurely and cannot perform its filtering function, causing the embolus to flow away with the lumen fluid.

[0069] To address the aforementioned issues, this specification provides a vena cava filter, wherein the stent portion, after being deployed, can contact the lumen wall and form a hollow channel, and the filter portion can be disposed within the hollow channel. Since one end of the filter portion is in a converged state, it can collect emboli in the lumen and contain the emboli within the hollow channel.

[0070] Since the filter section can include a biodegradable structure and a non-biodegradable coating applied to the biodegradable structure, the filter section will not be degraded during the collection of the embolus, thereby enabling continuous collection of the embolus and preventing embolus leakage. Subsequently, by removing the non-biodegradable coating, the biodegradable structure can be exposed and degraded, thereby controlling the conversion process of the vena cava filter and more effectively treating the embolus in the lumen.

[0071] To enable those skilled in the art to better understand and implement the embodiments of the present invention, the following describes in detail the concept, scheme, principle, and advantages of the embodiments of this specification in conjunction with the accompanying drawings and specific application examples.

[0072] Reference Figure 1 The diagram shown is a structural schematic of a vena cava filter in one embodiment of this specification. In some embodiments of this specification, such as... Figure 1 As shown, the vena cava filter M may include a stent section M1 and a filter section M2, wherein:

[0073] The support portion M1 has a telescopic state, and after unfolding, it contacts the cavity wall ( Figure 1 (Not shown) Contact, and a hollow channel K is formed;

[0074] The filter section M2 is disposed within the hollow channel K. One end (the end closer to the right in the current viewing angle) has a radial structure and is connected to the support section M1. The other end (the end closer to the left in the current viewing angle) is in a converging state, suitable for collecting emboli. Figure 1 (Not shown); and the filter section includes: a biodegradable structure M21, and a non-biodegradable coating applied to the biodegradable structure (…). Figure 1 (not shown), and the degradable structure M21 is adapted to degrade after the non-degradable coating is removed.

[0075] When the support part M1 is fully extended in the cavity wall, the edge of the support part M1 can contact the cavity wall and form a hollow channel K. The filter part M2 can be disposed in the hollow channel K. Since one end of the filter part M2 is in a gathered state, it can collect the embolus in the cavity and contain the embolus in the space where the hollow channel K is located.

[0076] Since the filter section M2 may include a degradable structure M21 and a non-degradable coating applied to the degradable structure, the filter section M2 will not be degraded during the collection of the embolus, thereby enabling continuous collection of the embolus and preventing its leakage. Subsequently, by removing the non-degradable coating, the degradable structure M21 can be exposed. The degradable structure M21 can be degraded, thereby controlling the conversion process of the vena cava filter and more effectively treating the embolus in the lumen wall.

[0077] To enable those skilled in the art to better understand and implement the embodiments of the present invention, some specific examples of the specific implementation of the vena cava filter in the embodiments of this specification are given below.

[0078] In some embodiments of this specification, the support portion may include multiple expansion units, which are coupled together to form a ring structure.

[0079] In practice, the expansion units can be connected sequentially in a preset order. When the support is fully expanded, on the one hand, each expansion unit can directly contact the cavity wall and play a supporting role; on the other hand, the annular structure formed between each expansion unit has a hollow channel, which can accommodate the embolus, avoid damaging the embolus, and thus remove the embolus in one go, improving the processing efficiency.

[0080] In practice, the support structure may include non-degradable metal materials, and the manufacturing method of the support structure may include at least one of the following: weaving, laser cutting, and 3D printing (3DP). For example, the support structure may be integrally formed by laser cutting, making the overall structure of the support structure more stable and reliable.

[0081] In other embodiments, the stent portion may also be made of a biodegradable metal material, thereby enabling the degradation of the entire vena cava filter structure without the need for secondary removal, reducing the probability of complications.

[0082] In some embodiments of this specification, the expansion unit may include multiple expansion members, which may be arranged in a circumferential array. By circumferentially arranging the expansion members, expansion units with different structures can be obtained, thereby forming a support portion with a corresponding structure, which can then adapt to different luminal walls, especially some more tortuous luminal walls, enhancing the universality of the vena cava filter.

[0083] In specific implementation, the expansion unit can be a concave expansion structure, and adjacent expansion members along the axial direction share the same end, while adjacent expansion members along the circumferential direction are connected by connectors.

[0084] As a specific example, combined with Figure 1 , refer to Figure 2a and Figure 2b The diagram shows some of the expansion units of the support section. For example, it illustrates that expansion units 10 and 20 can both be concave expansion structures, and adjacent expansion members share the same end along the axial direction. For example, expansion members 101 and 104 of expansion unit 10 can share the same end with other adjacent expansion units. Similarly, expansion members 201 and 204 of expansion unit 20 can share the same end with other adjacent expansion units. Expansion members 103 and 203 that are adjacent along the circumferential direction can be fixedly connected.

[0085] Furthermore, continue to refer to Figure 2a The concave expansion structure may include: a first arc-shaped member 101 (also referred to as an expansion member 101) and a second arc-shaped member 104 disposed opposite to each other; a first bending member 102 and a second bending member 103 disposed on both sides of the first arc-shaped member 101 and the second arc-shaped member 104, disposed opposite to each other and bent in opposite directions; and protruding ends disposed on both sides of the first bending member 102 and the second bending member 103, for example, protruding ends 12 disposed on both sides of the first bending member 102 and protruding ends 13 disposed on both sides of the second bending member 103. Since the first bending member 102 and the second bending member 103 can be bent relative to each other, a concave portion of the concave expansion structure can be formed.

[0086] In some embodiments of this specification, the protruding end 12 may be directly connected to the protruding end 13 to form an annular support portion.

[0087] The support portion with the above structure, by including the concave expansion structure including the first arc-shaped member and the second arc-shaped member arranged opposite to each other, can achieve smooth contact with the cavity wall when the support portion is fully extended, preventing puncture or scratching of the cavity wall; and the first bending member and the second bending member arranged on both sides of the first arc-shaped member and the second arc-shaped member, arranged opposite to each other and bent in opposite directions, can provide support stress for the support portion.

[0088] In some embodiments, the connector may be flexible, meaning that the connector may be made of flexible materials / structures.

[0089] In another specific embodiment, the expansion unit can be a tension-torsion expansion structure, and the expansion members adjacent along the axial direction are connected by a connector, and the ends of the expansion members adjacent along the circumferential direction with an arc are connected.

[0090] As a specific example, combined with Figure 1 , refer to Figure 3a and Figure 3b The diagram shows a portion of the expansion unit of the support section, such as... Figure 3a The bracket portion may include expansion units 30 to 60, and expansion units 30 to 60 are all tension-torsion type expansion structures, and expansion members adjacent along the axial direction and expansion members adjacent along the circumferential direction are fixedly connected.

[0091] For example, the expansion members of expansion units 30 and 40 that are adjacent along the axial direction can be fixedly connected; the expansion members of expansion units 50 and 60 that are adjacent along the axial direction can be fixedly connected; the expansion members of expansion units 30 that are adjacent along the circumferential direction can be fixedly connected to the expansion members of expansion unit 50; and the expansion members of expansion units 40 that are adjacent along the circumferential direction can be fixedly connected to the expansion members of expansion unit 60.

[0092] In some embodiments of this specification, when the expansion unit is a tension-torsion type expansion structure, each expansion unit may adopt the same structure. For example, the tension-torsion type expansion structure includes: an annular member; and a plurality of linear members distributed along the outer side of the annular member, and each adjacent expansion unit is fixedly connected by adjacent linear members.

[0093] As an example, such as Figure 3b As shown, the expansion unit 30 may include an annular member 31 and a plurality of linear members (e.g., ...) distributed along the outer side of the annular member 31. Figure 3b The linear members 32 to 35 shown are provided, wherein the expansion unit 30 can be fixedly connected to the linear member of the expansion unit 40 via the linear member 35.

[0094] It is understood that the above example illustrates a tensile unit having one annular member and four connected linear members. In other embodiments, the tensile unit may have other numbers of linear members, and this specification does not limit this, and the linear members can still be connected according to the above connection relationship.

[0095] In specific implementations, the support portion having the above structure can be obtained in the following ways. For example, the support portion can be integrally cut to form the support portion; or, for example, each expansion unit can be manufactured separately first, and then the tension-torsion structures can be welded together sequentially according to the above connection relationship. The embodiments in this specification do not limit the formation process of the support portion.

[0096] In another specific embodiment, the expansion unit can be an outwardly convex expansion structure, and adjacent expansion members are fixedly connected along the axial and circumferential directions.

[0097] As a specific example, combined with Figure 1 , refer to Figure 4a and Figure 4b The diagram shows a portion of the expansion unit of the support section, such as... Figure 4a The support portion may include expansion units 70 to 100, and the expansion units 70 to 100 are all convex expansion structures, and adjacent expansion members along the axial and circumferential directions can be fixedly connected.

[0098] For example, the expansion member of the axial expansion unit 70 can be fixedly connected to the expansion member of the adjacent expansion unit 80, the expansion member of the circumferential expansion unit 70 can be fixedly connected to the expansion member of the adjacent expansion unit 90, the expansion member of the axial expansion unit 90 can be fixedly connected to the expansion member of the adjacent expansion unit 100, and the expansion member of the circumferential expansion unit 80 can be fixedly connected to the expansion member of the adjacent expansion unit 100.

[0099] In some embodiments of this specification, when the expansion unit is an outwardly convex expansion structure, each expansion unit can adopt the same structure. For example, the outwardly convex expansion structure includes: a first convex member and a second convex member arranged opposite each other along the axial direction; a first concave member and a second concave member arranged opposite each other along the circumferential direction; and adjacent expansion units are respectively fixedly connected along the axial direction by adjacent first concave members and second concave members; and are respectively fixedly connected along the circumferential direction by adjacent first convex members and second convex members.

[0100] As an example, such as Figure 4b As shown, the expansion unit 70 may include a first convex member 72 and a second convex member 74 arranged opposite each other along the axial direction, and a first concave member 71 and a second concave member 73 arranged opposite each other along the circumferential direction. The expansion units 70 and 80 are fixedly connected along the axial direction through adjacent first concave members 71 and second concave members 73, the expansion units 90 and 100 are fixedly connected along the axial direction through adjacent first concave members and second concave members, and the expansion units 70 and 90 are fixedly connected along the circumferential direction through adjacent first convex members 72 and second convex members 74.

[0101] In specific implementation, we will continue to refer to Figure 4a and 4bThe first concave member 71 and the second concave member 73 may have the same structure. For example, the first concave member 71 may include a first component 711 and a second component 712, and the first concave member 73 may include a first component 731 and a second component 732.

[0102] The first convex member 72 and the second convex member 74 may have the same structure. For example, the first convex member 72 may include a third member 721 and a fourth member 722, and the second convex member 74 may include a first member 741 and a second member 742.

[0103] It is understood that the above example is illustrated using a tensile unit having two oppositely arranged concave members and two oppositely arranged convex members. In other embodiments, the number of concave members can be increased in the longitudinal direction, and the number of convex members can be increased in the transverse direction, thereby obtaining tensile units with different densities.

[0104] In another specific embodiment, the expansion unit can be a rotary expansion structure, and adjacent expansion members are fixedly connected along the axial and circumferential directions.

[0105] As a specific example, combined with Figure 1 , refer to Figure 5a and Figure 5b The diagram shows a portion of the expansion unit of the support section, such as... Figure 5a The support portion may include expansion units 110 to 140, and expansion units 110 to 140 are all rotational expansion structures, and adjacent expansion members along the axial and circumferential directions can be fixedly connected.

[0106] For example, the stretching element of the axial stretching unit 110 can be fixedly connected to the stretching element of the adjacent stretching unit 120; the stretching element of the circumferential stretching unit 110 can be fixedly connected to the stretching element of the adjacent stretching unit 130; the stretching element of the axial stretching unit 130 can be fixedly connected to the stretching element of the adjacent stretching unit 140; and the stretching element of the circumferential stretching unit 120 can be fixedly connected to the stretching element of the adjacent stretching unit 140.

[0107] In some embodiments of this specification, when the expansion unit is a rotary expansion structure, each expansion unit can adopt the same structure. For example, the rotary expansion structure may include: a first shank and a second shank arranged in an alternating manner, and teeth disposed at both ends of the first shank and the second shank and arranged in a centrally symmetrical manner; and adjacent expansion units are fixedly connected axially by adjacent teeth connected to the second shank; and fixedly connected circumferentially by adjacent teeth connected to the first shank.

[0108] As an example, such as Figure 5bAs shown, the expansion unit 110 may include a first shank 111 and a second shank 112 arranged in an alternating manner, wherein the first shank 111 and the second shank 112 may be connected at a rotation point O; teeth 113 and 114 are provided at both ends of the first shank 111, and teeth 115 and 116 are provided at both ends of the second shank 112, and the teeth 113 and 114, and teeth 115 and 116 are centrally symmetrical.

[0109] For adjacent expansion units located in different directions, their connection relationships are different. For example, adjacent expansion units 110 and 120 are fixedly connected axially by adjacent teeth 115 and 116 connected to the second shank 112, and adjacent expansion units 110 and 130 are fixedly connected circumferentially by adjacent teeth 113 and 114 connected to the first shank 111.

[0110] It is understood that the above example is illustrated using a tensioning unit having two handles and four teeth. In other embodiments, the tensioning unit may have other numbers of handles and teeth disposed on the handles, and this specification does not limit this.

[0111] In practical implementation, when the stent is fully deployed, it is easily impacted by the lumen fluid in the tube, and its shape may change or its position may deviate, thereby affecting the removal effect of the embolus. Based on this, the stent may also include: a groove structure, which is disposed on the side of each expansion unit near the lumen wall, wherein the groove structure arranged along the central axis of the vena cava filter is perpendicular to the central axis, and the groove structure arranged in the direction perpendicular to the central axis is parallel to the central axis, and the groove structures in the two directions are orthogonally arranged.

[0112] Therefore, by providing a groove structure on the side of the expansion unit near the cavity wall, the friction between it and the cavity wall can be increased, and the inner wall of the cavity can fully contact the groove structure. This can prevent the support part from moving axially and rotating along the central axis, effectively improving the support rigidity of the support part, reducing the risk of tilting and displacement, and enabling the support part to maintain a stable shape in the cavity, thereby improving the removal effect of emboli.

[0113] As an optional example, continue to refer to Figure 2a The groove structures 14 to 17 can be disposed on the side of the expansion unit 10 near the cavity wall, and the groove structures 24 to 27 can be disposed on the side of the expansion unit 20 near the cavity wall.

[0114] Among them, the groove structures 14 and 15 arranged along the central axis of the vena cava filter can be perpendicular to the central axis, and the groove structures 16 and 17 perpendicular to the central axis are parallel to the central axis, and the groove structures 14 and 15 are orthogonally arranged with the groove structures 16 and 17 respectively.

[0115] In some embodiments of this specification, the groove structure can be one or more of the following: a straight line, a cross, or an intersecting shape. In other embodiments, the shape of the groove structure can also be a regular polygonal structure such as a triangle or a square. This specification does not limit the shape of the groove structure in this way.

[0116] In practice, groove structures can be provided at the protruding ends on both sides of the first and second bent parts.

[0117] For example, continue to refer to Figure 2a Groove structures 18 are provided on the protruding ends 12 on both sides of the first bent member 102 and the protruding ends 13 on both sides of the second bent member 103.

[0118] Continue to refer to Figure 2a No groove structure is provided at the connection between the protruding end 12 and the expansion unit 10, and no groove structure is provided at the connection between the protruding end 13 and the expansion unit 20. This can improve the firmness of the connection, thereby improving the mechanical stability of the formed support part, so that the support part will not deform while supporting the cavity wall.

[0119] It should be noted that the above illustrations are for illustrative purposes only and do not represent the actual distribution of the groove structures on the expansion unit. They are only used to illustrate that the expansion unit can be equipped with groove structures; and the number and orientation of the groove structures are also for illustrative purposes. In specific implementations, the number and orientation of the groove structures can be flexibly set according to actual needs, and the embodiments in this specification do not impose any restrictions on this.

[0120] As mentioned earlier, one end of the filter section is in a converged state, which can collect the embolus and contain it within the hollow channel. In actual operation, the embolus can be directly removed from the body or dissolved within the body.

[0121] Based on this, in some embodiments of this specification, the stent portion may further include: a drug-carrying structure disposed on the side of each expansion unit away from the cavity wall, suitable for accommodating thrombolytic agents.

[0122] As an optional example, see [reference] Figure 2b The drug-loaded structure 19 can be disposed on the side of the expansion unit 10 away from the cavity wall, and the drug-loaded structure 19 can be disposed on the side of the expansion unit 20 away from the cavity wall. Both the drug-loaded structures 19 and 29 contain the thrombolytic material. The thrombolytic material can dissolve the embolism, dissolving the large embolism into a smaller embolism block, which is easier to remove, thereby reducing the probability of embolism.

[0123] In practical implementation, a groove structure can be set at the protruding end to set the drug-carrying structure.

[0124] For example, continue to refer to Figure 2b A drug-carrying structure 11 can be provided on the side of the protruding end 12(13) away from the cavity wall.

[0125] It should be noted that the above illustrations are for illustrative purposes only and do not represent the actual distribution of the drug-loaded structures on the expansion element. They are only used to illustrate that drug-loaded structures can be set in the expansion element; and the number and shape of the drug-loaded structures are also illustrative, for example, Figure 2b The cross-sectional shape of the drug-loaded structure is circular. In other embodiments, the cross-sectional shape of the drug-loaded structure can be square. This specification does not limit this embodiment.

[0126] In actual operation, a certain distance is maintained between the vena cava filter and the embolus. When the vena cava filter reaches or approaches the embolus, the release of the thrombolytic agent achieves the best thrombectomy effect, thereby dissolving larger emboli into smaller embolic fragments for easier removal and reducing the probability of embolism. Based on this, in some embodiments of this specification, the stent portion further includes an encapsulation layer adapted to coat the drug-loaded structure and, after degradation, used to release the thrombolytic agent to dissolve the embolus in the lumen.

[0127] In practice, the encapsulation layer coated on the drug-loaded structure can be removed using various methods. For example, the encapsulation layer can be shattered by ultrasound; the encapsulation layer can be destroyed by other devices; or the encapsulation layer can react with the lumen fluid in the cavity. This specification does not limit these methods.

[0128] It is understood that the solutions in the above embodiments can be combined and cross-referenced without conflict, thereby extending to a variety of possible implementation schemes. These can all be considered as the implementation schemes disclosed and made public in the embodiments of this specification, and the embodiments of this specification do not limit these extended schemes.

[0129] For example, Figures 3a to 5b The illustrated support portion may also have one or more of the following: a drug-carrying structure, a groove structure, and an encapsulation structure, and the above structures are... Figures 3a to 5b The distribution of the support components shown can be referred to the description in the foregoing embodiments, and will not be repeated here.

[0130] In a specific implementation, the filtration section may include: a filtration unit comprising multiple filtration structures, one end of each filtration structure being connected to the support section for collecting the emboli, and each filtration element being coated with the non-degradable coating; and a constraint unit connected to the other end of each filtration structure to form the agglomerated state, and the constraint unit being coated with the non-degradable coating.

[0131] As an optional example, combined Figure 1, refer to Figure 6 The filter section M2 may include a filter unit 200 and a constraint unit 300. The filter unit 200 may include filter structures 210 to 270. One end of the filter structures 210 to 270 (the end closer to the left in the current view) is connected to the support section M1 to form a radial structure. The other end of the filter structures 210 to 270 is connected to the constraint unit 300. Both the filter structures 210 to 270 and the constraint unit 300 are coated with a non-degradable coating.

[0132] In a specific implementation, when the support part M1 is fully extended, the end of the filter structure 210 to 270 connected to the support part M1 has a radial structure (i.e., has an opening), through which the embolus can be collected; the end of the filter structure 210 to 270 connected to the restraint unit 300 is in a converged state, which can prevent the embolus from flowing to other places.

[0133] During the process of dissolving the embolus, the filter structures 210 to 270 and the restraint unit 300 are coated with a non-degradable coating and will not be degraded.

[0134] Once the embolus has completely dissolved or most of the embolus has dissolved, the non-degradable coating on the filter structures 210 to 270 and the restraint unit 300 can be removed, for example, by ultrasonic removal, exposing the filter structures 210 to 270 and the restraint unit 300. Since the filter structures 210 to 270 and the restraint unit 300 are all degradable structures, they begin to degrade at this point. Therefore, by employing the above method, the conversion process of the vena cava filter can be controlled.

[0135] In some embodiments of this specification, both the filtering unit and the constraint unit may be made of shape memory material.

[0136] In some embodiments of this specification, the filter structure is a multi-layer radial structure. By setting the filter structure as a multi-layer radial structure, the resulting filter structure has a lower density, which, while ensuring unobstructed flow of the cavity fluid, can improve the capture effect of emboli and prevent emboli from flowing to other places, thereby reducing the probability of blockage.

[0137] As a specific example, the filter structure includes a plurality of first filter elements, which are of equal or unequal length and are staggered to form the multi-layered radial structure.

[0138] For example, continue to refer to Figure 6The filter structure 270 may include two first filter elements, and the lengths of these two first filter elements may be equal and they may be staggered to form two layers of radial structure; or, for example, the filter structure 240 may include three first filter elements, the lengths of these three first filter elements may be unequal, and the first filter element located above the current viewing angle has the longest length and they may be staggered to form two layers of radial structure.

[0139] It is understood that the number of first filter elements included in the above-described filter structure and the number of layers of the radial structure are merely illustrative examples. The embodiments in this specification do not limit the number of first filter elements included in each filter structure. In some embodiments, the number of first filter elements included in each filter structure may be the same or different, and in the same filter unit, the number of layers of the radial structure formed by different numbers of first filter elements may be the same or different; the number of first filter elements included in each layer of radial structure may be the same or different, for example in... Figure 6 The radial structure shown is a two-layer structure, and the number of first filter elements contained in the first layer can be less than the number of first filter elements contained in the second layer. This specification does not impose any restrictions on this embodiment, as long as the first filter elements can be staggered to form a multi-layer radial structure.

[0140] In practice, to further increase the density of the filter section, a weaving method can also be used to form the filter section.

[0141] As a specific example, such as Figure 7a The schematic diagram shown in this specification illustrates another vena cava filter in an embodiment of this invention. Figure 1 The difference between the vena cava filter shown in the diagram and the one in the diagram is that... Figure 1 The filter section M2 is formed by multiple first filter elements distributed in an alternating manner, and Figure 7a The filter section M2 is formed by weaving together multiple filter structures. The similarities between the two can be found in the preceding content and will not be described further here.

[0142] Correspondingly, when the filter section is a woven structure, the filter structure includes a plurality of second filter elements, the plurality of second filter elements having equal or unequal lengths, which are woven together to form the multi-layer radial structure.

[0143] For example, refer to Figure 7b The filter structure 400 may include second filter elements 410 to 470, and the second filter elements 410 to 470 may have the same length. The second filter elements 410 to 470 may be woven together to form two radial structures. Furthermore, the second filter elements 410 to 470 and the support portion M1 may be connected through the woven loops of the second filter elements 410 to 470.

[0144] In other examples, the lengths of the second filter elements 410 to 470 may not be exactly the same. The embodiments in this specification do not limit the length of the second filter element.

[0145] In practice, the second filter element can be made of flexible materials / structures, which makes the filter structure more flexible and can be smoothly deployed in cavities of various special shapes, improving the flexibility and versatility of the filter structure, and causing less damage to the blood vessel wall.

[0146] For example, as shown in 7a and 7b, the filter structure 400 can be a grid rhombus structure formed by a flexible material / structure connected to the constraint unit 500 and the support part M1, and one end of the grid rhombus structure is tapered into a cone shape, while the other end is radial.

[0147] Specifically, the flexible material / structure may include braided filaments. The type and thickness of the braided filaments can be selected according to specific scenarios and requirements. For example, the braided filaments can be metal wires and / or polymer wires, with a thickness ranging from 0.1 mm to 0.4 mm. Further, the polymer can be nickel-titanium (NiTi) alloy wire. This specification does not specifically limit the type and thickness of the braided filaments in its embodiments.

[0148] It is understood that the above-described filter structure is merely an illustrative example. In a specific embodiment, the filter structure can be a single-layer radial structure, which can be integrally formed using a cutting process.

[0149] It is understood that the solutions in the above embodiments can be combined and cross-referenced without conflict, thereby extending to a variety of possible implementation schemes. These can all be considered as the implementation schemes disclosed and made public in the embodiments of this specification, and the embodiments of this specification do not limit these extended schemes.

[0150] To enable those skilled in the art to more clearly understand and implement the working process of the vena cava filter provided in the embodiments of this specification, the following illustrative description is provided with reference to the accompanying drawings and specific examples. For ease of understanding, the following examples use thrombi in blood vessels as emboli; however, in practical applications, the emboli removal device provided in the embodiments of this specification can be applied to other emboli, and the embodiments of this specification do not limit the type of emboli.

[0151] In an optional example, such as Figures 8 to 10 The diagram shown is a schematic representation of the working process of a vena cava filter in a blood vessel, as provided in an embodiment of this specification.

[0152] Reference Figure 8In this diagram, sub-figure (a) is a schematic diagram of the unfolded vena cava filter, and sub-figure (b) is a side view of sub-figure (a). The filter unit B can consist of filter elements b1 to b2. 18 Composition, and filter elements b1 to b 18 One end is connected to the support part A to form a radial structure, and the other end is connected to the constraint unit C to form a converged state.

[0153] like Figure 8 As shown, a vena cava filter is inserted into the blood vessel from which thrombus removal is needed. When the filter passes through the thrombus a certain distance (this distance depends on the specific requirements and thrombus volume), the stent portion A can automatically deploy within the blood vessel, conforming to the inner wall of the vessel. Simultaneously, the filter portion within the hollow channel also automatically deploys. When the filter portion is fully deployed, the filter unit B and the restraint unit C are fixed together, allowing them to jointly capture the thrombus and facilitate blood flow. Since both filter unit B and restraint unit C are coated with a non-degradable coating, they will not degrade, thus continuously collecting the thrombus and preventing it from flowing out.

[0154] Reference Figure 9 In this diagram, sub-figure (a) is a schematic diagram of the partial degradation of the vena cava filter, and sub-figure (b) is a side view of sub-figure (a).

[0155] like Figure 9 As shown, once the thrombus is captured or the patient has passed the critical period, the drug-loaded structure on stent A can release thrombolytic agents to dissolve the thrombus. When the thrombus is completely or mostly dissolved, ultrasound can be used to break up the non-degradable coatings on filter unit B and restraint unit C, thereby exposing filter unit B and restraint unit C. Since filter unit B and restraint unit C are degradable structures, restraint unit C and filter unit B begin to degrade. Figure 9 As shown, the constraint unit C in the vena cava filter is completely degraded, meaning the vena cava filter no longer includes the constraint unit C. However, due to shape memory properties, filter elements b1 to b... 18 It bounces back towards the blood vessel wall and is gradually degraded, such as Figure 9 As shown in sub-figure (b), filter elements b1 to b 18 The length becomes shorter.

[0156] Reference Figure 10 In this diagram, sub-figure (a) is a schematic diagram of the complete degradation of the vena cava filter, and sub-figure (b) is a side view of sub-figure (a).

[0157] like Figure 10 As shown, during the degradation process, because stent A is a non-degradable structure, stent A remains inside the blood vessel and continues to support it, while the filter elements b1 to b...18 Continue to degrade, such as Figure 10 As shown in neutron diagram (b), up to filter element b1 to b 18 The symptoms disappear. Blood flow is also fully restored, thus reducing the chance of a recurrence.

[0158] In some embodiments of this specification, the stent portion A may also be made of a biodegradable metal material, thereby allowing the entire structure of the vena cava filter to be degraded.

[0159] In practice, to determine the location of the vena cava filter within the blood vessel, angiography can be used to position the thrombectomy device. For example, a positioning component can be placed proximal to the stent. Angiography allows for precise determination of the vena cava filter's position within the blood vessel, ensuring that the thrombus remains within the space occupied by the deployed filter.

[0160] It should be noted that, unless otherwise explicitly specified and limited, the terms used in this specification can be understood according to different application scenarios. For example, the verb "connect" can be understood as a fixed connection, a detachable connection, a rotating connection, an integral connection, etc.; and the verb "unfold" can be understood as an expansion, extension, etc. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0161] It should be noted that in the description of this specification, terms such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with terms such as "first" and "second" may explicitly or implicitly include one or more of that feature. Furthermore, terms such as "first" and "second" are used to distinguish similar objects and are not necessarily used to describe a specific order or indicate importance. It is understood that such terms can be used interchangeably where appropriate.

[0162] While the embodiments disclosed in this specification are as described above, the present invention is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A vena cava filter, characterized in that, include: The support section has a telescopic state, and after unfolding, it contacts the cavity wall and forms a hollow channel; The filter section is located inside the hollow channel. One end of the filter section has a radial structure and is connected to the support section, while the other end is in a converging state, which is suitable for collecting emboli. Furthermore, the filter section is a biodegradable structure and also includes a non-biodegradable coating applied to the biodegradable structure, and the biodegradable structure is adapted to degrade after the non-biodegradable coating is removed, wherein the non-biodegradable coating is adapted to be removed by ultrasonic waves.

2. The vena cava filter according to claim 1, characterized in that, The support portion includes: Multiple expansion units are coupled and connected to form a ring structure.

3. The vena cava filter according to claim 2, characterized in that, The expansion unit includes multiple expansion members, which are arranged in a circumferential array.

4. The vena cava filter according to claim 3, characterized in that, The expansion unit is a concave expansion structure, and adjacent expansion members along the axial direction share the same end, while adjacent expansion members along the circumferential direction are fixedly connected.

5. The vena cava filter according to claim 4, characterized in that, The concave traction structure includes: The first and second arc-shaped components are set relative to each other; A first bent member and a second bent member are disposed on both sides of the first arc-shaped member and the second arc-shaped member, respectively, and are bent relative to each other; and The protruding ends are provided on both sides of the first bent member and the second bent member.

6. The vena cava filter according to claim 3, characterized in that, The expansion unit is a tension-torsion expansion structure, and the expansion members adjacent along the axial direction and the expansion members adjacent along the circumferential direction are all fixedly connected.

7. The vena cava filter according to claim 6, characterized in that, The tension-torsion type expansion structure includes: Ring-shaped component; And a plurality of linear members distributed along the outer side of the annular member, and each adjacent expansion unit is fixedly connected by adjacent linear members.

8. The vena cava filter according to claim 3, characterized in that, The expansion unit is an outwardly convex expansion structure, and adjacent expansion members are fixedly connected along the axial and circumferential directions.

9. The vena cava filter according to claim 8, characterized in that, The convex expansion structure includes: A first convex member and a second convex member are arranged opposite each other along the axial direction; A first concave part and a second concave part are arranged opposite each other in the circumferential direction; Furthermore, adjacent expansion units are fixedly connected axially via adjacent first concave and second concave members, respectively; and circumferentially via adjacent first convex and second convex members, respectively.

10. The vena cava filter according to claim 3, characterized in that, The expansion unit is a rotary expansion structure, and adjacent expansion members are fixedly connected along the axial and circumferential directions.

11. The vena cava filter according to claim 10, characterized in that, The rotary expansion structure includes: a first shank and a second shank arranged in an alternating manner, and teeth disposed at both ends of the first shank and the second shank and arranged in a centrally symmetrical manner; Furthermore, adjacent expansion units are fixedly connected axially via adjacent teeth that connect to the second shank; adjacent expansion units are fixedly connected circumferentially via adjacent teeth that connect to the first shank.

12. The vena cava filter according to claim 2, characterized in that, The support portion also includes: The groove structure is provided on the side of each expansion unit near the wall of the lumen. The groove structure arranged along the central axis of the vena cava filter is perpendicular to the central axis, and the groove structure arranged in the direction perpendicular to the central axis is parallel to the central axis. The groove structures in the two directions are orthogonally arranged.

13. The vena cava filter according to claim 12, characterized in that, The groove structure is one or more of the following: straight, cross, or intersecting.

14. The vena cava filter according to claim 2, characterized in that, The support portion also includes: The drug-carrying structure is located on the side of each expansion unit away from the cavity wall, and is suitable for containing thrombolytic agents.

15. The vena cava filter according to claim 14, characterized in that, The support portion also includes: An encapsulation layer, adapted to be coated on the drug-loaded structure, and used after degradation to release the thrombolytic agent to dissolve emboli in the lumen.

16. The vena cava filter according to claim 1, characterized in that, The filtration unit includes: The filtration unit includes multiple filtration structures, one end of each filtration structure is connected to the support portion, and is adapted to collect the embolus, and each filtration structure is coated with the non-degradable coating. A constraint unit is connected to the other end of each filter structure to form the aggregated state, and the constraint unit is coated with the non-degradable coating.

17. The vena cava filter according to claim 16, characterized in that, The filter structure is a multi-layered radial structure.

18. The vena cava filter according to claim 17, characterized in that, The filtration structure includes multiple first filter elements, which are of equal or unequal length and are staggered to form the multi-layered radial structure.

19. The vena cava filter according to claim 17, characterized in that, The filtration structure includes multiple second filter elements, which are of equal or unequal length and are interwoven to form the multi-layered radial structure.

20. The vena cava filter according to any one of claims 16-19, characterized in that, The filtering unit and the constraint unit are made of shape memory material.

21. The vena cava filter according to claim 1, characterized in that, The support structure is made of biodegradable or non-biodegradable metal material.

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