Recyclable inferior vena cava filter
The retrievable inferior vena cava filter with a double-layer circumferential point contact fixed structure solves the problems of poor neutrality and difficult retrieval, improves the thrombus capture rate and reduces the risk of intimal hyperplasia, and achieves stable and low-cost production.
Patent Information
- Application Number
- CN202422838238.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-20
- Publication Date
- 2025-12-16
- Estimated Expiration
- 2034-11-20
AI Technical Summary
Existing retrievable inferior vena cava filters have structural problems such as poor alignment, difficulty in retrieval, intimal hyperplasia, and poor filtration effect. In particular, traditional umbrella-shaped filters are prone to displacement, cylindrical filters have high implantation resistance and intimal hyperplasia, and dual-headed bundled filters have high production costs and poor capture effect.
The retrievable inferior vena cava filter with a double-layer circumferential point contact fixing structure includes first and second filter rods. The first filter rod is connected to the retrieval column, and the end of the second filter rod is provided with a positioning hook, forming a concave shape to ensure centering and stability, reduce the contact area with the blood vessel wall, and improve the thrombus capture rate.
It achieves good neutrality and stability, reduces the risk of intimal hyperplasia, improves thrombus capture rate, reduces the impact on blood flow, and lowers production costs.
Smart Images
Figure CN223668114U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model belongs to the technical field of medical instrument and equipment, and relates to a recoverable inferior vena cava filter. BACKGROUND
[0002] Deep vein thrombosis (DVT) is a venous return disorder caused by abnormal blood clotting in deep veins, often occurring in the lower limbs. Thrombus detachment can cause pulmonary embolism (PE), and DVT and PE are collectively referred to as venous thromboembolism (VTE), which is a manifestation of the same disease at different stages. The main adverse consequences of DVT are PE and post-thrombotic syndrome (PTS), which can significantly affect the quality of life of patients and even cause death.
[0003] An inferior vena cava filter (IVCF) is a device designed to prevent the detachment of thrombi from the inferior vena cava system, which can cause pulmonary embolism (PE). It can effectively prevent fatal PE and is widely used in clinical practice. The inferior vena cava filter can capture large thrombus clots, and then dissolve or decompose the large thrombus clots into smaller blood clots through catheter thrombolytic therapy, which can disperse to the small branches of the pulmonary artery, reducing the impact of thrombus on pulmonary circulation.
[0004] The inferior vena cava filters on the market are mainly divided into three types: permanent, recoverable and convertible inferior vena cava filters. Permanent filters and convertible inferior vena cava filters will remain in the human body permanently. They have fewer complications in the short term after being implanted in the body, but the probability of serious complications such as displacement, fracture, perforation, and inferior vena cava obstruction will greatly increase with time, thus losing their due value. The recoverable filter can be effectively avoided after completing the filtering task, but due to the larger contact area between the support part and the blood vessel wall, it is easy to cause intimal hyperplasia and other phenomena, making the recoverable filter difficult to recover, causing damage to the blood vessel wall during recovery, incomplete collection of thrombus, and thrombus left over.
[0005] Traditional inferior vena cava filters can be divided into umbrella-shaped, cylindrical and double-head cluster-shaped in structure. The umbrella-shaped inferior vena cava filter is mainly composed of a plurality of slender filter rods and support rods to form a filtering part, which converges on a recovery body at one end. This type of filter is prone to tilting during implantation and cannot guarantee good centring. The angle of inclination is random, and a severe inclination angle can cause uneven deployment of the filter, resulting in difficulty in recovering the filter, reduced filtering effect of thrombus, and serious complications such as perforation.
[0006] The traditional cylindrical vena cava filter is mainly composed of a plurality of support rods connecting filter rods to form a support and filter part, and the filter rods are gathered on a recovery body at one end. The filter of this type ensures good centring when the filter is implanted, but has a large resistance when the filter is released from the sheath, and is prone to elastic load jumping, which causes certain damage to the cavity. On the other hand, the support body has a large contact area with the blood vessel after the filter is implanted, which is prone to intimal hyperplasia and other phenomena, causing difficulty in recovering the filter.
[0007] The traditional double-head cluster vena cava filter has a bulky waist support body structure, and the filter body is connected to the support body at both ends and gathered on a recovery body at one end. The filter of this type can ensure good support and is not prone to tilting, but has poor capture effect on free thrombus, and the length of the nickel-titanium shape memory alloy pipe required for production is too long and difficult to shape, resulting in high production cost. Similarly, the support body has a large contact area with the blood vessel after the filter is implanted, which is prone to intimal hyperplasia and other phenomena, causing difficulty in recovering the filter. Practical new type
[0008] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a recoverable inferior vena cava filter which has good structural stability, good wall adhesion, good centring, good anti-falling property, high embolus capture rate and small influence on blood flow. The main problem solved by the present application is the low capture rate and easy deviation of the traditional umbrella-shaped filter, and the poor centring. The double-layer circumferential point contact is fixed to the blood vessel wall to ensure good centring, and the problems of large contact area of the traditional cylindrical support rod, easy intimal hyperplasia and difficulty in recovering the filter are solved.
[0009] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is:
[0010] The present application provides a recoverable inferior vena cava filter, comprising a recovery column and a vena cava filter body having an expanded and contracted state, wherein the recovery column is provided with a recovery hook, and the vena cava filter body comprises a plurality of first filter rods and a plurality of second filter rods; the first filter rod comprises a first sub-rod, a second sub-rod and a third sub-rod, the top end of the first sub-rod is connected to the recovery column, the end of the first sub-rod is connected to the top end of the second sub-rod and the third sub-rod respectively, and the end of the second sub-rod and the third sub-rod is respectively provided with a first positioning hook; the top end of the second filter rod is connected to the recovery column, and the end of the second filter rod is provided with a second positioning hook; in the expanded state, each of the first filter rods and the second filter rods is uniformly distributed in a ring shape around the axis of the recovery column, and the height of the second filter rod is higher than that of the first filter rod; the distance between each of the first filter rods and the central axis of the recovery column is equal; the distance between each of the second filter rods and the central axis of the recovery column is equal; and the centers of the circular arcs of the first filter rods and the second filter rods are on the side away from the central axis of the recovery column.
[0011] In some embodiments of the utility model, when the inferior vena cava filter body is in the expanded state, the ends of the first filter rod and the second filter rod are distributed on the same diameter circle with the axis of the recovery column as the center.
[0012] In some embodiments of the utility model, when the inferior vena cava filter body is in the expanded state, the second sub-rod and the third sub-rod are evenly distributed on the circumference.
[0013] In some embodiments of the utility model, when the inferior vena cava filter body is in the expanded state, the first sub-rod and the second sub-rod and the third sub-rod form a herringbone filter rod.
[0014] In some embodiments of the utility model, when the inferior vena cava filter body is in the expanded state, the second filter rod is a semicircular filter rod away from the axis of the recovery column and with the opening direction close to the recovery column.
[0015] In some embodiments of the utility model, the number of the first filter rod and the second filter rod is the same, and the first filter rod and the second filter rod are arranged at intervals.
[0016] In some embodiments of the utility model, the number of the first sub-rod is 4-16, the number of the second sub-rod is 4-16, and the number of the third sub-rod is 4-16.
[0017] In some embodiments of the utility model, the number of the second filter rod is 4-16.
[0018] In some embodiments of the utility model, in the expanded state, the first positioning hook is respectively arranged outside the end of the second sub-rod and the end of the third sub-rod.
[0019] In some embodiments of the utility model, the shape of the first positioning hook is different from that of the second positioning hook.
[0020] In some embodiments of the utility model, the lengths of the first positioning hooks are equal.
[0021] In some embodiments of the utility model, the shape of the first positioning hook is 1 / 4 circle, and the radius of the first positioning hook is 0.1-0.5 mm.
[0022] In some embodiments of the utility model, the second positioning hook is arranged outside the end of the second filter rod.
[0023] In some embodiments of the utility model, the lengths of the second positioning hooks are equal.
[0024] In some embodiments of this utility model, the angle between the tangent direction at the connection point of the second positioning hook and the second filter rod is 30 to 60°.
[0025] Due to the application of the above technical solution, this utility model has the following advantages compared with the prior art:
[0026] This retrievable vena cava filter features a double-layered filtration structure achieved through the height adjustment of the first and second filter rods. The distances from each first filter rod to the central axis are equal, and the distances from each second filter rod to the recovery column are also equal, demonstrating excellent alignment. Furthermore, the arc centers of the first and second filter rods are located on the outer side (away from the axis), creating a concave shape. This, in addition to the aforementioned advantages, also facilitates filter recovery.
[0027] Furthermore, since the angle between the ends of the second and third sub-rods (herringbone filter rods) and the blood vessel wall is relatively large after the filter is released, an arc-shaped positioning hook is preferred; while the angle between the end of the second filter rod and the blood vessel wall is relatively small (almost 0 degrees), the angle between the second positioning hook and the tangent direction at the connection point of the second filter rod is preferably 30-60° (thus forming a Y-shaped structure similar to the end of the second filter rod). This is beneficial for accurate filter positioning and reliable fixation.
[0028] Furthermore, the second filter rod adopts a concave semi-circular shape, which facilitates filter recovery. Existing filter rods are mostly convex, which is not conducive to recovery.
[0029] Furthermore, the second and third sub-bars form a herringbone filter bar, which evenly divides the space away from the axis, preventing emboli from falling off in areas away from the axis. This helps improve the efficiency of thrombus filtration, and the increased support points contribute to the stability of the filter.
[0030] Furthermore, the ends of the first and second filter rods have the same diameter and are coaxial on the circumference. This structure offers good stability, excellent centering, and good anti-detachment properties. The first and second filter rods are evenly distributed on the circumference, resulting in a high thrombus capture rate and filtration effect. It can filter thrombi from multiple angles and directions while minimizing impact on blood flow. In the retracted state, the length of the first filter rod is greater than the length of the second filter rod, ensuring material conservation and reducing production costs. Attached Figure Description
[0031] Figure 1 This is a schematic diagram of the recyclable vena cava filter of this utility model in its deployed state;
[0032] Figure 2 for Figure 1 The right view of the retrievable vena cava filter shown;
[0033] Figure 3 for Figure 1 a top view of the retrievable vena cava filter shown in Fig.
[0034] Figure 4 for Figure 1 a structural schematic view of the retrievable vena cava filter shown in Fig.
[0035] Figure 5 a structural schematic view of the first positioning hook on the first filtering rod of the retrievable vena cava filter of the utility model;
[0036] Figure 6 a structural schematic view of the second positioning hook on the second filtering rod of the retrievable vena cava filter of the utility model.
[0037] Reference numerals in the drawing
[0038] 1 retrieval column
[0039] 2 retrieval hook
[0040] 3 first filtering rod
[0041] 31 first sub-rod
[0042] 32 second sub-rod
[0043] 33 third sub-rod
[0044] 4 second filtering rod
[0045] 5 first positioning hook
[0046] 6 second positioning hook DETAILED DESCRIPTION
[0047] In the description of the utility model, it is necessary to explain that the structure, ratio, size and the like shown in the drawings attached to the specification are merely used to cooperate with the content disclosed in the specification, for understanding and reading by the person skilled in the art, and are not used to limit the limiting conditions that the utility model can be implemented, so it does not have the substantial meaning of technology, any modification of structure, change of proportional relationship or adjustment of size, as long as it does not affect the effect and the purpose that the utility model can produce, should still fall within the range that the technical content disclosed in the utility model can cover. Meanwhile, the orientation or position relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or position relationship shown in the drawings, and is only used to facilitate the description of the utility model and simplify the description, and therefore cannot be understood as indicating or implying that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the utility model. In addition, the terms "first" and "second" are only used for description purposes and cannot be understood as indicating or implying relative importance.
[0048] In the description of the utility model, it should be explained that, unless otherwise specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected, it can be mechanically connected, or it can be electrically connected, it can be directly connected, or it can be indirectly connected through an intermediate medium, it can be the communication inside two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific situation.
[0049] In addition, in the description of the utility model, unless otherwise stated, the meaning of "multiple" is two or more.
[0050] As Figures 1 to 6 The utility model discloses an embodiment relates to a recyclable inferior vena cava filter, including recovery column 1 and having the inferior vena cava filter body of expansion and contraction state, recovery hook 2 is equipped on recovery column 1, the inferior vena cava filter body includes multiple first filter rod 3 and multiple second filter rod 4 respectively with recovery column 1 is connected.
[0051] The recyclable inferior vena cava filter provided by the utility model comprises Figure 1 And 2, the first filter rod 3 includes a first sub-rod 31, a second sub-rod 32 and a third sub-rod 33, the top end of the first sub-rod 31 is connected with the recovery column 1, the end of the first sub-rod 31 is connected with the top end of the second sub-rod 32 and the third sub-rod 33 respectively, and a plurality of first positioning hooks 5 are further connected with the end of the second sub-rod 32 and the third sub-rod 33 respectively. Figure 1 , for example, in the unfolded state, the first filter rod 3 is a herringbone filter rod.
[0052] In the recyclable inferior vena cava filter provided by the utility model, like Figure 1 and 2 , the top end of the second filter rod 4 is connected with the recovery column 1, and the end of the second filter rod 4 is connected with the second positioning hook 6. In some specific embodiments, like Figure 1 and 2 , for example, in the unfolded state, the second filter rod 4 is a semicircular filter rod. Specifically, the second filter rod 4 is a semicircular filter rod which is away from the axis of the recovery column 1 and has an opening direction close to the recovery column 1.
[0053] When the inferior vena cava filter body is in the unfolded state, like Figure 1 and 2 , the three parts of the first filter rod 3 are unfolded, the first sub-rod 31 and the second sub-rod 32 and the third sub-rod 33 form a herringbone filter rod. The ends of the second sub-rod 32 and the third sub-rod 33 are connected with the first positioning hook 5 and are uniformly distributed on the circumference, the second filter rod 4 is unfolded, the end of the second filter rod 4 is connected with the second positioning hook 6 and is uniformly distributed on the circumference, like Figure 3 , the ends of the first filter rod 3 and the second filter rod 4 are distributed on the same diameter circumference with the axis of the recovery column 1 as the center. In the unfolded state, the ends of the first filter rod 33 and the second filter rod 44 are coaxial and have the same diameter on the circumference, and the diameter size is 22-26 mm, and the end parts of the first filter rod 3 and the second filter rod 4 are uniformly distributed on the circumference.
[0054] When the inferior vena cava filter body is in the unfolded state, like Figures 1 to 3 , the first filter rod 3 is away from the central axis of the recovery column 1 by an equal distance, the second filter rod 4 is away from the central axis of the recovery column 1 by an equal distance, and each second filter rod is away from the recovery column by an equal distance, which embodies good centering. The centers of the arcs of the first filter rod 3 and the second filter rod 4 are on the side away from the central axis of the recovery column 1, so that the filter rod arc forms a concave shape, which has the above-mentioned advantages and is also beneficial to the recovery of the filter. Figure 4When the inferior vena cava filter body is in the collapsed state, the rod members of the first filter rods and the second filter rods are collapsed towards the central axis of the recovery column 1.
[0055] In use, when the inferior vena cava filter is placed in the blood vessel, the inferior vena cava filter body naturally expands and unfolds, each first filter rod 3 is first attached to the blood vessel wall, the ends of the second sub-rod 32 and the third sub-rod 33 are connected to the first positioning hook 5, which is uniformly distributed on the blood vessel wall, then the second positioning hook 6 connected to the end of each second filter rod 4 is uniformly distributed on the blood vessel wall, which ensures the stability of the inferior vena cava filter, the double-layer structure formed by the first filter rod and the second filter rod ensures good centring, the first positioning hook 5 at the end of the first filter rod 3 and the second positioning hook 6 at the end of the second filter rod 4 prevent them from tilting under the impact of gravity or blood. Each first filter rod 3 uses point contact with the first positioning hook 5, and each second filter rod 4 uses point contact with the second positioning hook 6, which reduces the contact area with the blood vessel wall, reduces the damage to the blood vessel wall by the inferior vena cava filter, and prevents intimal hyperplasia and other phenomena.
[0056] The first filter rod 3 and the second filter rod 4 at different angles to the central axis of the recovery column 1 can further improve the filtering efficiency, the inferior vena cava filter adopts the double-layer filtering structure of the first filter rod 3 and the second filter rod 4, which can reduce the disturbance to the blood flow while ensuring the filtering of multi-angle thrombus, and can reduce the occurrence of hemolysis.
[0057] Preferably, the first group of filter rods and the second group of filter rods are uniformly distributed in a ring shape around the axis of the recovery column 1, the ends of the first filter rod 3 and the second filter rod 4 have the same diameter size on the circumference and are coaxial, which further improves the stability of the inferior vena cava filter and makes the inferior vena cava filter centring good.
[0058] According to one embodiment, each of the first filter rod 3 and the second filter rod 4 has good mechanical deformation behavior, which facilitates the unfolding and collapsing of the inferior vena cava filter body.
[0059] Further, the top end of the first sub-rod 31 of the first filter rod 3 is connected to the recovery column 1, the end of the first sub-rod 31 of the first filter rod 3 is connected to the top end of the second sub-rod 32 and the third sub-rod 33, and the end of the second sub-rod 32 and the third sub-rod 33 of the first filter rod 3 is connected to the first positioning hook 5. The top end of the second filter rod 4 is connected to the recovery column 1, and the end of the second filter rod 4 is connected to the second positioning hook 6, which ensures sufficient space for accommodating thrombus and improves the capture rate of thrombus, ensuring smooth blood flow while filtering thrombus.
[0060] Preferably, when the inferior vena cava filter body is in the unfolded state, the second sub-rod 32 and the third sub-rod 33 of the first filter rod 3 are uniformly distributed on the circumference.
[0061] Preferably, the number of the first filter rods 3 and the second filter rods 4 is the same, and the first filter rods 3 and the second filter rods 4 are arranged at intervals.
[0062] Preferably, the number of the first filter rods 3 and the second filter rods 4 is the same, and the first filter rods 3 and the second filter rods 4 are arranged at intervals.
[0063] Preferably, the number of the first filter rods 3 and the second filter rods 4 is the same, and the first filter rods 3 and the second filter rods 4 are arranged at intervals.
[0064] In this embodiment, the number of the first filter rods 3 and the second filter rods 4 is 4, and the structure is symmetrical and stable, and is good in centering.
[0065] Preferably, the recovery column 1 is a cylindrical solid column or a tubular body, and the recovery hook 2 is arranged on the recovery column 1, and the recovery hook 2 is used for hanging with a recovery device, so that the whole inferior vena cava filter is separated from the blood vessel.
[0066] Preferably, the first positioning hook 5 is arranged at the outer side of the end of the second sub-rod 32 and the end of the third sub-rod 33 (the outer side is the side away from the central axis of the recovery column 1 in the expanded state). The shape of the first positioning hook 5 at the outer end of the first filter rod 3 and the second filter rod 4 is different, and the first positioning hook 5 and the second positioning hook 6 can penetrate into the inner wall of the blood vessel, so that the inferior vena cava filter is kept stable.
[0067] Further preferably, as shown in Figure 5 , the lengths of the first positioning hooks 5 are equal, for example, the first positioning hook 5 is an arc-shaped positioning hook, the shape of the first positioning hook 5 is 1 / 4 of a circle, and the radius of the first positioning hook 5 is 0.1-0.5 mm.
[0068] Further preferably, as shown in Figure 1 and 6 , the second positioning hook 6 is arranged at the outer side of the lower end of the second filter rod 4 (the outer side is the side away from the central axis of the recovery column 1 in the expanded state). The lengths of the second positioning hooks 6 are equal, the second positioning hook 6 has a certain angle with the second filter rod 4, and the angle between the tangent direction at the connection position of the second positioning hook 6 and the second filter rod 4 is 30-60° (the Y-shaped structure formed by the second positioning hook and the end of the second filter rod is shown in Figure 6 ).
[0069] The utility model discloses a filter can adopt one or more of stainless steel, memory alloy, cobalt-chromium alloy, biodegradable metal, biodegradable polymer to process. According to the path on filter design drawing paper, laser cutting is carried out, then through pickling, electrochemistry process, heat treatment and polishing treatment to obtain finished product. In addition, the filter can also adopt nickel-titanium alloy pipe material, and the finished product is formed after laser cutting and heat setting.
[0070] Preferably, after processing and shaping, the first filter rod 3 and the second filter rod 4 are both cuboid-shaped, and the width of each is 0.1-0.8mm, and the thickness is 0.1-0.8mm. In order to make the drawings more simple and clear, the filter rod assembly and the support rod in each drawing are represented by a line.
[0071] The working principle of the recyclable inferior vena cava filter provided by the utility model is as follows:
[0072] When the filter is released, the first positioning hook 5 on the first filter rod 3 is first pushed out of the outer sheath tube, the first filter rod 3 naturally expands and opens, the first positioning hook 5 pierces into the blood vessel wall, the second positioning hook 6 of the second filter rod 4 is pushed out of the outer sheath tube, the second filter rod 4 naturally expands and opens, the second positioning hook 6 pierces into the blood vessel wall, and the filter naturally expands and opens.
[0073] When the filter is recycled, the operation steps are as follows: 1. blood vessel puncture is performed, and a long sheath tube of a certain length is pushed forward; 2. the long sheath tube is used to push forward a loop catheter; 3. under the development equipment, the loop is used to catch the recovery hook 2 of the thrombus filter; 4. the loop is fixed, and the catheter is pushed forward to the thrombus filter recovery hook 2; 5. the long sheath tube is fixed, and the loop catheter is withdrawn, until the filter is completely pulled into the long sheath tube.
[0074] In summary, after the utility model is released, the end of the first filter rod 3, the end of the second filter rod 4 and the first positioning hook 5 and the second positioning hook 6 contact the blood vessel wall, adopt double-layer circumferential point contact to fix and adhere to the blood vessel wall, ensure the stability and centring of the vena cava filter, and prevent it from tilting under the impact of gravity or blood. The vena cava filter adopts the double-layer different-angle structure formed by the first filter rod 3 and the second filter rod 4, improves the capture efficiency, reduces the disturbance to blood flow while filtering thrombus, can reduce the occurrence of hemolysis, and improves the thrombus filtering effect through the first filter rod 3 and the second filter rod 4.
[0075] In summary, the utility model effectively overcomes the various shortcomings in the prior art and has high industrial utilization value.
[0076] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the present application should be covered by the claims of the present application.
Claims
1. A retrievable inferior vena cava filter, comprising: The invention discloses a vena cava filter, which comprises a recovery column (1) and a vena cava filter body with an expanded and a contracted state, the recovery column (1) is provided with a recovery hook (2), the vena cava filter body comprises a plurality of first filter rods (3) and a plurality of second filter rods (4); the first filter rod (3) comprises a first sub-rod (31), a second sub-rod (32) and a third sub-rod (33), the top end of the first sub-rod (31) is connected with the recovery column (1), the end of the first sub-rod (31) is connected with the top end of the second sub-rod (32) and the third sub-rod (33) respectively, the end of the second sub-rod (32) and the third sub-rod (33) is respectively provided with a first positioning hook (5); the top end of the second filter rod (4) is connected with the recovery column (1), and the end of the second filter rod (4) is provided with a second positioning hook (6); in the expanded state, the first filter rod (3) and the second filter rod (4) are evenly distributed in a ring shape around the axis of the recovery column (1) respectively, and the height of the second filter rod (4) is higher than that of the first filter rod (3); the distance between each first filter rod (3) and the central axis of the recovery column (1) is equal; the distance between each second filter rod (4) and the central axis of the recovery column (1) is equal; the center of the circular arc of the first filter rod (3) and the second filter rod (4) is on the side away from the central axis of the recovery column (1).
2. The recoverable inferior vena cava filter of claim 1, wherein, When the vena cava filter body is in the expanded state, the ends of the first filter rod (3) and the second filter rod (4) are distributed on the same diameter circle with the axis of the recovery column (1) as the center.
3. The recoverable inferior vena cava filter of claim 1, wherein, When the vena cava filter body is in the expanded state, the second sub-rod (32) and the third sub-rod (33) are evenly distributed on the circumference. When the vena cava filter body is in the expanded state, the first sub-rod (31) forms a herringbone filter rod with the second sub-rod (32) and the third sub-rod (33). When the vena cava filter body is in the expanded state, the second filter rod (4) is a semicircular filter rod away from the axis of the recovery column (1) and with the opening direction close to the recovery column (1).
4. The recoverable inferior vena cava filter of claim 1, wherein, The number of the first filter rod (3) and the second filter rod (4) is the same, and the first filter rod (3) and the second filter rod (4) are arranged at intervals.
5. The recoverable inferior vena cava filter of claim 1, wherein, The number of the first sub-rod (31) is 4-16, the number of the second sub-rod (32) is 4-16, and the number of the third sub-rod (33) is 4-16.
6. The recoverable inferior vena cava filter of claim 1, wherein, The number of the second filter rod (4) is 4-16.
7. The recoverable inferior vena cava filter of claim 1, wherein, In the expanded state, the first positioning hook (5) is arranged outside the end of the second sub-rod (32) and the end of the third sub-rod (33) respectively.
8. The recoverable inferior vena cava filter of claim 1, wherein, The shape of the first positioning hook (5) is different from that of the second positioning hook (6).
9. The recoverable inferior vena cava filter of claim 1, wherein, The length of each first positioning hook (5) is equal. The shape of the first positioning hook (5) is 1 / 4 of a circle, and the radius of the first positioning hook (5) is 0.1-0.5 mm.
10. The recoverable inferior vena cava filter of claim 1, wherein, In the expanded state, the second positioning hook (6) is arranged outside the end of the second filter rod (4). The length of each second positioning hook (6) is equal. And / or, the angle between the tangent direction at the connection between the second positioning hook (6) and the second filtering rod (4) is 30-60°.