Secondary vena cava filter

Abstract

The vena cava secondary filter comprises: a recovery body and a filter body, wherein the recovery body and the filter body are fixedly connected and suitable for recovering the filter body; the filter body comprises a plurality of first filter rods and a plurality of second filter rods; the first filter rod comprises: a long rod extending outward from the proximal end of the filter body, the plurality of long rods forming a radial structure; a first anchor provided at the distal end of the long rod; the second filter rod comprises: a first support portion extending outward from the proximal end of the filter body to the maximum diameter of the filter body and then extending inward to support the blood vessel wall; a cutting portion, one end of which is fixedly connected to the first support portion and curled in the reverse direction at the bottom of the filter body to extend toward the recovery body; a second anchor provided at the end of the cutting portion facing the recovery body. The above-mentioned vena cava secondary filter can reduce the resistance during the transportation and recovery of the vena cava secondary filter, and perform secondary filtration and cutting on thrombi formed in the vena cava.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of medical devices, and in particular to a vena cava secondary filter. Background Art

[0002] Pulmonary embolism (PE) and deep venous thrombosis (DVT) are collectively referred to as venous thromboembolism (VTE). Among vascular diseases, VTE is estimated to be the third most common, after acute coronary syndrome and stroke. Due to its lack of specific clinical manifestations, misdiagnosis and missed diagnosis are common, making it a significant cause of mortality.

[0003] The vena cava filter (VCF) is a filtration device designed to prevent pulmonary embolism (PE) caused by dislodged thrombi in the superior and inferior vena cava systems. Since the first generation of filters were first used clinically in 1967, over 50 years of continuous improvement and innovation have resulted in the development of various types and structures of venous filters for clinical use. Currently, they are primarily categorized as permanent and non-permanent filters.

[0004] Permanent filters are more suitable for patients with advanced age, a clear underlying condition causing VTE (such as thrombophilia, immune disorders, or other conditions that cause hypercoagulability) that is difficult to resolve in the short term, contraindications to long-term anticoagulation (such as hemophilia), or a neoplastic disease with a short life expectancy. Studies have demonstrated that filter implantation can effectively reduce the incidence of PE. However, long-term implantation can lead to complications such as inferior vena cava perforation, filter migration, secondary thrombosis leading to inferior vena cava occlusion, and recurrent DVT, limiting their widespread use.

[0005] Non-permanent filters are new products designed to replace permanent filters. They primarily include retrievable and temporary filters. Temporary filters are associated with a high incidence of complications (such as infection, filter displacement, and rupture). Retrievable filters also present some clinical challenges, but they remain a major area of ​​filter development.

[0006] The key points of recyclable filters are to optimize the concept of "recyclability". The main points are:

[0007] 1. Extend the time window for retrievability. Currently, most retrievable filters are allowed to remain in the body for a very short time window, often 2 to 3 weeks. During this period, many patients' VTE risks or anticoagulation contraindications have not been completely eliminated, so the filter retention time has to be extended. Once this time window is exceeded, problems such as thrombosis and endometrialization often make the filter difficult to remove, resulting in a permanent filter being placed in the body, which in turn faces a series of problems faced by permanent filter implantation.

[0008] 2. Improve the retrieval rate. Improve the design in terms of structure and operability to increase the filter retrieval rate. Mainly in terms of stability, increase the filter's ability to resist tilting, perforation, and displacement.

[0009] Figure 1 It is a vena cava filter in the prior art, referring to Figure 1 The vena cava filter includes a first filter portion 1100 and a second filter portion 1200 with opposite openings; the first filter portion 1100 is formed by gradually extending outward in a positive direction from the center and gradually flipping and curling in the opposite direction, and the first filter portion 1100 is point-supported on the inner wall of the blood vessel; the second filter portion 1200 is formed by gradually extending outward in a positive direction from the center; the first filter portion 1100 is provided with an anchor barb 1300 extending in a reverse direction for anchoring on the inner wall of the blood vessel, and the second filter portion 1200 is provided with an anchor barb 1400 extending in a forward direction for anchoring on the inner wall of the blood vessel. The first filter portion 1100 of the vena cava filter, including the anchor barb 1300, has a small overall bending radius, a large angle, and great rigidity. The resistance when retracting into the sheath is great, and the filter is easily stuck on the outer wall of the sheath, thereby increasing the difficulty of retrieval. At the same time, the vena cava filter can only filter once and does not have the function of cutting blood clots. Since blood clots with a diameter greater than 1 cm may cause pulmonary embolism in clinical practice, the vena cava filter is prone to cause pulmonary embolism and large venous thrombosis in the lower limbs to block the vena cava. Summary of the Invention

[0010] In view of this, an embodiment of the present invention provides a vena cava secondary filter, which can reduce the resistance during the delivery and recovery process, and perform secondary filtration and cutting of thrombi formed in the vena cava.

[0011] An embodiment of the present invention provides a vena cava secondary filter, comprising: a recovery body and a filter body, wherein the recovery body and the filter body are fixedly connected and suitable for recovering the filter body; the filter body comprises a plurality of first filter rods and a plurality of second filter rods; the first filter rod comprises: a long rod extending outward from the proximal end of the filter body, and a plurality of the long rods form a radial structure; a first anchor is arranged at the distal end of the long rod; the second filter rod comprises: a first support portion extending outward from the proximal end of the filter body to the maximum diameter of the filter body and then extending inward to support the blood vessel wall; a cutting portion, one end of which is fixedly connected to the first support portion, and is reversely curled at the bottom of the filter body and extends toward the recovery body; a second anchor is arranged at the end of the cutting portion facing the recovery body.

[0012] Optionally, the cutting portion includes: a first cutting portion, one end of which is fixedly connected to the first supporting portion, extending toward the bottom of the filter body, and suitable for cutting thrombus; a second cutting portion, one end of which is fixedly connected to the first cutting portion, extending toward the bottom of the filter body, and curling in the opposite direction to extend toward the recovery body, and suitable for cutting thrombus.

[0013] Optionally, the filter body further includes: a plurality of balance rods; the balance rod includes: a first extension portion extending outward from the proximal end of the filter body; a second extension portion fixedly connected to the first extension portion and extending in a direction parallel to the axis of the filter body to form linear contact with the blood vessel wall.

[0014] Optionally, at least one of the plurality of first filter rods, the second filter rods, and the plurality of balance rods is symmetrically arranged along the axis of the filter body.

[0015] Optionally, an angle at which the first support portion of the second filter rod extends outward from the proximal end of the filter body is greater than an angle at which the long rod of the first filter rod extends outward from the proximal end of the filter body.

[0016] Optionally, the length of the first extension portion of the balance rod is smaller than the length of the first support portion of the second filter rod extending outward from the proximal end of the filter body to the maximum diameter of the filter body.

[0017] Optionally, the extending direction of the first anchor is the same as the extending direction of the first filter rod; and the extending direction of the second anchor is opposite to the extending direction of the first anchor.

[0018] Optionally, the first anchor and / or the second anchor includes: a base; a fixing thorn extending separately from the base; and a limiting member extending separately from the base and forming an angle with the fixing thorn.

[0019] Optionally, the length of the limiting member is greater than that of the fixing thorn, and the end of the limiting member away from the base includes an extension structure extending toward one side of the fixing thorn.

[0020] Optionally, the end of the fixing thorn away from the base is nested inside the limiting member.

[0021] Optionally, the recovery body includes: a cone, fixedly connected to the filter body; and a hook, provided on the cone, suitable for recovering the vena cava secondary filter.

[0022] Optionally, the hook portion is arranged at the top of the cone, and the center is hollowed out to form a hook-shaped structure.

[0023] Optionally, the recovery body includes: two symmetrically arranged recovery pieces, the overall outline of the recovery piece is a cone-shaped structure, and a hook portion is hollowed out at the top of the cone-shaped structure.

[0024] Optionally, the recovery body includes a base and a bending portion fixedly connected to the base, wherein:

[0025] The base portion has a first end fixedly connected to the filter body, and a second end fixedly connected to the first end of the bent portion;

[0026] The second end of the bent portion extends toward the filter body and forms a recovery hook integrally with the base.

[0027] Optionally, the base includes a first linear member; the bending portion includes: a second linear member extending radially outward, and an angle between the second linear member and the first linear member is in the range of 0 to 45 degrees.

[0028] Optionally, the base includes: a third linear member; the bending portion includes: a fourth linear member, which is fixedly connected to the third linear member and arranged parallel or nearly parallel to the third linear member, and the distance between the fourth linear member and the third linear member is less than a preset distance threshold.

[0029] According to the solution of an embodiment of the present invention, a filter body is provided, comprising a plurality of first filter rods and a plurality of second filter rods, wherein the second filter rod comprises a cutting portion, one end of the cutting portion is fixedly connected to the first support portion, and is reversely curled at the bottom of the filter body and extends toward the recovery body, and a second anchor is provided at the end of the cutting portion toward the recovery body. Since the second anchor and the cutting portion are reversely flipped and curled as a whole at the end of the vena cava secondary filter and have a large curvature, it is convenient for the vena cava secondary filter to enter the sheath and move therein during the delivery or recovery process, thereby reducing the resistance during the delivery and recovery of the vena cava secondary filter, and at the same time, the thrombus can be cut and primary filtration can be achieved. Furthermore, since the first filter rod comprises a long rod extending outward from the proximal end of the filter body, the plurality of long rods form a radial structure, and therefore, the thrombus cut and filtered by the cutting portion can be secondary filtered. In summary, the vena cava secondary filter can reduce the resistance during delivery and recovery, and has the function of secondary filtering and cutting the thrombus formed in the vena cava.

[0030] Furthermore, by arranging a plurality of balance bars on the vena cava secondary filter, the balance performance of the vena cava secondary filter in the blood vessel can be enhanced, the vena cava secondary filter can be prevented from tilting in the blood vessel, and the stability of the vena cava secondary filter in the blood vessel can be improved.

[0031] Furthermore, by setting multiple first filter rods, second filter rods, and at least one of multiple balance rods, and symmetrically arranging them along the axis of the filter body, the overall balance of the vena cava secondary filter is further enhanced, and the stability of the vena cava secondary filter in the blood vessel is improved.

[0032] Furthermore, by setting the angle at which the first support portion of the second filter rod extends outward from the proximal end of the filter body to be greater than the angle at which the long rod of the first filter rod extends outward from the proximal end of the filter body, the structure of the first filter rod and the second filter rod is made more stable, which is beneficial to the working coordination between the first filter rod and the second filter rod, and further improves the stability of the overall structure of the vena cava secondary filter.

[0033] Furthermore, by setting the length of the first extension portion of the balance rod to be smaller than the length of the first support portion of the second filter rod extending outward from the proximal end of the filter body to the maximum diameter of the filter body, the overall structure of the balance body is made more stable, thereby better exerting the balancing and stabilizing role of the balance body, and further improving the overall stability of the vena cava secondary filter.

[0034] Furthermore, by setting the extension direction of the first anchor to be the same as the extension direction of the first filter rod and the extension direction of the second anchor to be opposite to the extension direction of the first anchor, the possibility of displacement or offset of the vena cava secondary filter in the blood vessel when responding to stress from different directions can be prevented. The bidirectional setting of the first anchor and the second anchor can enable the vena cava secondary filter to have a bidirectional anti-displacement function, thereby further improving the stability of the vena cava secondary filter in the blood vessel.

[0035] Furthermore, by providing the first anchor and / or the second anchor to include a base, a fixing thorn extending separately from the base, and a limiting member extending separately from the base and having an angle with the fixing thorn, on the one hand, the vena cava secondary filter can be more stably fixed to the blood vessel wall through the fixing thorn, thereby improving the stability of the vena cava secondary filter in the blood vessel; on the other hand, since the limiting member has a certain limiting effect on the depth of the fixing thorn penetrating into the blood vessel, it can prevent the fixing thorn from penetrating too deep into the blood vessel, thereby avoiding the possibility of the fixing thorn piercing the blood vessel and causing damage to the blood vessel.

[0036] Furthermore, by setting the length of the limiter to be greater than that of the fixed thorn, and the end of the limiter away from the base including an extension structure extending toward one side of the fixed thorn, the limiter can better play a role in limiting the depth of the fixed thorn inserted into the blood vessel, thereby better avoiding the possibility of the fixed thorn causing damage to the blood vessel due to deep insertion of the blood vessel.

[0037] Furthermore, by arranging the end of the fixing thorn away from the base to be nested inside the limiting member, the structure of the first anchor and / or the second anchor is made simpler, the structural design of the first anchor and / or the second anchor is optimized, and the risk of component falling off is reduced; on the other hand, the limiting member can limit the depth of the fixing thorn inserted into the blood vessel, thereby reducing the damage to the blood vessel caused by the fixing thorn being inserted too deep into the blood vessel.

[0038] Furthermore, by arranging the recovery body to include a cone fixedly connected to the filter body, the recovery body as a whole has a certain taper, which reduces the diameter of the head end of the recovery body, so that the vena cava secondary filter is easy to be captured by the capture system catheter during the recovery process; on the other hand, since the setting of the cone has a self-centering function, during the recovery process, after the hook contacts the capture system catheter, the center of the recovery body and the axis of the capture system catheter can be automatically aligned under the action of tension, so that the vena cava secondary filter can be conveniently and stably entered into the sheath during the recovery process, thereby improving the retrievability of the vena cava secondary filter.

[0039] Furthermore, by arranging the hook portion at the top of the cone and hollowing out the center of the cone to form a hook-shaped structure, the vena cava secondary filter can be more easily captured by the capture system catheter during the recovery process, further improving the retrievability of the vena cava secondary filter.

[0040] Furthermore, by setting the recovery body to include two symmetrically arranged recovery parts, the overall outline of the recovery part is a conical structure, and the top of the conical structure is hollowed out to form a hook. On the one hand, the symmetrically arranged recovery parts can improve the fault tolerance of being captured by the capture system catheter during the recovery process. On the other hand, since the overall outline of the recovery part is a conical structure, the recovery part has a certain taper, thereby reducing the diameter of the head end of the recovery body, making the vena cava secondary filter easier to be captured by the capture system catheter during the recovery process.

[0041] Furthermore, by setting the base of the recovery body, the first end of which is fixedly connected to the filter body, and the second end of which is fixedly connected to the first end of the bending portion, the second end of the bending portion of the recovery body extends toward the filter body, forming a recovery hook with the base as a whole, so that the capture system can more easily capture the recovery hook, thereby improving the recyclability of the vena cava filter.

[0042] Furthermore, by setting the second linear member of the bending portion to extend radially outward and the angle between it and the first linear member is in the range of 0 to 45 degrees, the vena cava filter is not easy to fall off when it is captured by the capture system, thereby improving the capture success rate of the vena cava filter and further improving the recyclability of the vena cava filter.

[0043] Furthermore, by setting the fourth linear member of the bending portion to be fixedly connected to the third linear member, and being arranged parallel or nearly parallel to the third linear member, and the distance between the fourth linear member and the third linear member is less than a preset distance threshold, the vena cava filter is less likely to be detached when captured by the capture system, thereby improving the capture success rate of the vena cava filter and further improving the retrievability of the vena cava filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0045] Figure 1 A schematic structural diagram of a vena cava filter in the prior art is shown;

[0046] Figure 2A schematic structural diagram of a vena cava secondary filter provided by an embodiment of the present invention is shown;

[0047] Figure 3 A schematic structural diagram of another vena cava secondary filter provided by an embodiment of the present invention is shown;

[0048] Figure 4 A schematic structural diagram of a first anchor or a second anchor provided by an embodiment of the present invention is shown;

[0049] Figure 5 A schematic structural diagram of another first anchor or second anchor provided by an embodiment of the present invention is shown;

[0050] Figure 6 A schematic structural diagram of another first anchor or second anchor provided by an embodiment of the present invention is shown;

[0051] Figure 7 A schematic diagram of the partial structure of a recovery body of a vena cava secondary filter provided by an embodiment of the present invention is shown;

[0052] Figure 8 and Figure 9 Shows a schematic structural diagram of another vena cava secondary filter recovery body provided by an embodiment of the present invention at different angles;

[0053] Figure 10 A schematic structural diagram of another recovery body provided by an embodiment of the present invention is shown;

[0054] Figure 11 A schematic structural diagram of another recovery body provided by an embodiment of the present invention is shown;

[0055] Figure 12 Schematic diagram of the structure of the experimental filter used as a reference substance in simulation experiment 1 according to an embodiment of the present invention is shown;

[0056] Figure 13 A photograph showing the control substance capturing thrombus in simulation experiment 2 according to an embodiment of the present invention is shown;

[0057] Figure 14 A photograph showing the experimental article capturing thrombus in simulation experiment 2 according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0058] In order to make the above-mentioned objects, features and advantages of the embodiments of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0059] Figure 2 A schematic diagram of the structure of a vena cava secondary filter provided by an embodiment of the present invention is shown. Figure 2The vena cava secondary filter includes: a recovery body 1 and a filter body 2, wherein the recovery body 1 and the filter body 2 are fixedly connected and suitable for recovering the filter body 2; the filter body 2 includes a plurality of first filter rods 21 and a plurality of second filter rods 22.

[0060] In which, the first filter rod 21 may include: a long rod 211, extending outward from the proximal end of the filter body 2, and multiple long rods 211 form a radial structure; a first anchor 212, arranged at the distal end of the long rod 211; the second filter rod 22 may include: a first support part 221, extending outward from the proximal end of the filter body 2 to the maximum diameter of the filter body 2 and then extending inward to support the blood vessel wall; a cutting part 222, one end of which is fixedly connected to the first support part 221, and is reversely curled at the bottom of the filter body 2 and extends toward the recovery body 1; a second anchor 223, arranged at the end of the cutting part 222 facing the recovery body 1.

[0061] In an embodiment of the present invention, a secondary vena cava filter comprises a recovery body 1 and a filter body 2, which are fixedly connected, specifically by welding. The recovery body 1 can be docked with a filter capture tool and temporarily connected to the filter capture tool, allowing the filter capture tool to be operated and the filter body 2 to be retrieved through the recovery body 1.

[0062] Continue to refer Figure 2 In an embodiment of the present invention, the filter body 2 may be composed of a plurality of first filter rods 21 and a plurality of second filter rods 22. The plurality of first filter rods 21 and the plurality of second filter rods 22 are formed by extending outward from the proximal end of the filter body 2. The proximal end of the filter body 2 is where the filter body 2 is connected to the recovery body 1.

[0063] In a specific implementation, the material used for the filter body 2 may be a shape memory alloy, such as nickel-titanium alloy.

[0064] In the embodiment of the present invention, the first filter rod 21 can be a long rod 211, which, as the name implies, is relatively long. In specific implementations, the number of the multiple long rods 211 can be selected according to actual conditions and is not specifically limited here. For example, in some embodiments, the number of the multiple long rods 211 can be selected within the range of 2 to 6 according to actual conditions. Figure 2 As shown, in this embodiment of the present invention, the number of the plurality of long rods 211 is four.

[0065] In a specific embodiment, multiple long rods 211 extend outward from the proximal end of the filter body 2 to form a radial structure. Specifically, the multiple long rods 211 extend from the proximal end of the filter body 2 in a direction parallel to the axis of the filter body 2 for a short distance, and then extend relatively straight in a direction at a certain angle to the axis of the filter body 2. The angle between the multiple long rods 211 and the axis of the filter body 2 can be selected according to actual circumstances, for example, it can be selected between 20° and 45°, and is not specifically limited here. Specifically, the short distance between the head ends of the multiple long rods 211 and the axis of the filter body 2 allows the multiple long rods 211 to converge at the proximal end of the filter body 2, thereby making the overall structure of the vena cava secondary filter more harmonious and smooth, which is beneficial to improving the overall stability of the vena cava secondary filter.

[0066] In some embodiments of the present invention, the first filter rod 21 may further include a first anchor 212, which may be disposed at the distal end of the long rod 211, wherein the first anchor 212 may fix the vena cava secondary filter in the blood vessel, and may enable the vena cava secondary filter to cope with stress from the direction from the recovery body 1 to the filter body 2 in the blood vessel, thereby preventing the vena cava secondary filter from being displaced toward the filter body 2.

[0067] In a specific implementation, multiple first filter rods 21 can be symmetrically arranged along the axis of the filter body 2. Specifically, when multiple first filter rods 21 are symmetrically arranged along the axis of the filter body 2, the axis of the radial structure formed by multiple long rods 211 coincides with the axis of the filter body 2. As a result, the multiple first filter rods 21 are more symmetrical in structure, so that the multiple first anchors 212 can be anchored more symmetrically and firmly on the blood vessel wall, thereby maximizing the stability of the vena cava secondary filter in the blood vessel.

[0068] Continue to refer Figure 2 In some embodiments of the present invention, the second filter rod 22 may be composed of a first support portion 221 and a cutting portion 222. It should be noted that the first support portion 221 and the cutting portion 222 may be fixedly connected or integrated, and the specific choice may be based on actual needs.

[0069] In a specific implementation, the number of the second filter rods 22 can be selected according to actual conditions and is not specifically limited here. For example, in some embodiments, the number of the second filter rods 22 can be selected in the range of 2 to 6 according to actual conditions. Figure 2 As shown, in a specific embodiment, the number of the second filter rods 22 is 4. Due to the viewing angle, Figure 2 The number of the plurality of second filter rods 22 is shown as 2, but is actually 4.

[0070] In some embodiments of the present invention, the first support portion 221 may extend outward from the proximal end of the filter body 2 to the maximum diameter of the filter body 2 and then extend inward. Specifically, the maximum diameter of the filter body 2 is located at the outermost side of the filter body 2. The first support portion 221 forms an arch-shaped support structure at the maximum diameter of the filter body 2. In this way, the first support portion 221 forms a point contact with the blood vessel wall in the blood vessel. The first support portion 221 supports the vena cava secondary filter, thereby ensuring that the vena cava secondary filter can be stably located in the blood vessel, thereby improving the stability of the vena cava secondary filter.

[0071] It should be noted that the first support portion 221 extends outward from the proximal end of the filter body 2 to the maximum diameter of the filter body 2, and may continue to extend a short distance in a direction parallel to the axis of the filter body 2 before extending inward. In this way, the first support portion 221 forms linear contact with the blood vessel wall within the blood vessel, thereby enabling the first support portion 221 to better perform its supporting function, allowing the vena cava secondary filter to be more stably located within the blood vessel, further improving the stability of the vena cava secondary filter.

[0072] In some embodiments of the present invention, the cutting portion 222 of the second filter rod 22 reversely curls at the bottom of the filter body 2 and extends toward the recovery body 1. Specifically, the cutting portion 222 can continue to extend toward the bottom of the filter body 2 along the extension direction of the first support portion 221, and reversely curl at the bottom of the filter body 2. After the cutting portions 222 of multiple second filter rods 22 intersect at the bottom of the filter body 2, they each reversely curl and extend toward the recovery body 1, thereby forming a first-level filtration structure at the bottom of the filter body 2; at the same time, due to the structural arrangement of the cutting portions 222 of the multiple second filter rods 22, a larger volume of thrombus can be cut, so that the larger volume of thrombus is divided into multiple smaller volumes of thrombus after cutting.

[0073] In a specific implementation, since the multiple first filter rods 21 are composed of multiple long rods 211, and the multiple long rods 211 are radially arranged toward the bottom of the filter body 2, the filter structure formed by the multiple first filter rods 21 can recover thrombi from the filter body 2 to the recovery body 1; and since the cutting portions 222 of the multiple second filter rods 22 are reversely curled at the bottom of the filter body 2 and extend toward the recovery body 1, the filter structure formed by the cutting portions 222 of the multiple second filter rods 22 can recover thrombi from the recovery body 1 to the filter body 2; at the same time, it can also accommodate smaller volumes of thrombi after being cut by the cutting portions 222, thereby achieving secondary filtration.

[0074] It is understood that the configuration of the multiple long rods 211 and the multiple cutting portions 222 of the vena cava secondary filter can, on the one hand, achieve a bidirectional thrombus recovery function, that is, the vena cava secondary filter can recover thrombi in both the direction from the filter body 2 to the recovery body 1 and from the recovery body 1 to the filter body 2; on the other hand, it can cut and secondary filter larger thrombi, thereby, to a certain extent, preventing large thrombi in the lower limb veins from blocking the vena cava. In summary, the configuration of the multiple cutting portions 222 curling in opposite directions at the bottom of the filter body 2 further enhances the secondary filtration function of the vena cava secondary filter.

[0075] In some embodiments of the present invention, a second anchor 223 can be provided at the end of the cutting portion 222 in the direction toward the recovery body 1, wherein the second anchor 223 can fix the vena cava secondary filter in the blood vessel, and can enable the vena cava secondary filter to cope with the stress from the direction from the filter body 2 to the recovery body 1 in the blood vessel, thereby preventing the vena cava secondary filter from being displaced toward the recovery body 1.

[0076] In order to further realize the cutting function of the vena cava secondary filter, the cutting portion can be configured to include a plurality of cutting portions of different shapes.

[0077] Continue to refer Figure 2 The cutting portion 222 may include: a first cutting portion 2221 and a second cutting portion 2222, wherein: the first cutting portion 2221, one end of which is fixedly connected to the first supporting portion 221, extends toward the bottom of the filter body 2, and is suitable for cutting thrombus; the second cutting portion 2222, one end of which is fixedly connected to the first cutting portion 2221, extends toward the bottom of the filter body 2, and curls in the opposite direction to extend toward the recovery body 1, and is suitable for cutting thrombus.

[0078] In a specific implementation, the shape of the first cutting portion 2221 can be various, for example, it can be a straight line shape, or it can be a shape with a certain curvature. As a specific example, Figure 2 As shown, the first cutting portion 2221 is in a straight line shape, suitable for cutting thrombus.

[0079] In some embodiments of the present invention, the second cutting portion 2222 is curled and has a large curvature. First, the second cutting portion 2222 can cut the thrombus. Second, the second cutting portion 2222 with a large curvature can reduce the resistance during the delivery and recovery of the vena cava secondary filter. Finally, the second cutting portion 2222 can recover the thrombus from the recovery body 1 to the filter body 2, thereby realizing two-way recovery of the thrombus.

[0080] In a specific implementation, since the first anchor 212 can prevent the vena cava secondary filter from being displaced toward the filter body 2, and the second anchor 223 can prevent the vena cava secondary filter from being displaced toward the recovery body 1, the vena cava secondary filter can achieve bidirectional anti-displacement through the first anchor 212 and the second anchor 223, thereby making the vena cava secondary filter more stably present in the blood vessel, further improving the stability of the vena cava secondary filter.

[0081] like Figure 2 As shown, in a specific implementation, the extension direction of the first anchor 212 can be the same as the extension direction of the first filter rod 21; the extension direction of the second anchor 223 can be opposite to the extension direction of the first anchor 212, thereby enabling the vena cava secondary filter to more stably cope with stress from different directions in the blood vessel, thereby better realizing the bidirectional anti-displacement function.

[0082] In a specific implementation, multiple second filter rods 22 can be symmetrically arranged along the axis of the filter body 2, so that the overall structure of the multiple second filter rods 22 is more symmetrical, so that the multiple second anchors 223 can be more symmetrically and firmly anchored on the blood vessel wall, thereby further improving the stability of the vena cava secondary filter in the blood vessel.

[0083] In the embodiment of the present invention, since the second anchor 223 and the cutting portion 222 are reversely curled as a whole at the bottom of the filter body 2 and have a large curvature, it is beneficial for the vena cava secondary filter to enter the sheath and move therein during the transportation or recovery process, thereby reducing the resistance and the risk of scraping out powder during the transportation and recovery of the vena cava secondary filter, thereby improving the retrievability of the vena cava secondary filter.

[0084] Figure 3 FIG. 1 shows a schematic diagram of the structure of another vena cava secondary filter provided by an embodiment of the present invention, with reference to FIG. Figure 3 ,and Figure 2 The difference of the illustrated vena cava secondary filter is that the filter body 2 further includes: a plurality of balance bars 23. The balance bars 23 may include: a first extension portion 231 extending outward from the proximal end of the filter body 2; and a second extension portion 232 fixedly connected to the first extension portion 231 and extending in a direction parallel to the axis of the filter body 2 to form linear contact with the blood vessel wall.

[0085] In the embodiment of the present invention, the number of the balance bars 23 can be selected according to actual conditions and is not specifically limited herein. For example, in some embodiments, the number of the balance bars 23 can be selected within the range of 4 to 8 according to actual conditions. Figure 3 As shown, as an optional example, the number of the balancing poles 23 is four.

[0086] Continue to refer Figure 3 The balance bar 23 is composed of a first extension portion 231 and a second extension portion 232. In a specific implementation, the connection between the first extension portion 231 and the second extension portion 232 can be a fixed connection, such as welding, or the two can be integrally formed. The specific connection method can be selected according to actual conditions.

[0087] In some embodiments of the present invention, the first extension portion 231 first extends a short distance from the proximal end of the filter body 2 toward the bottom of the filter body 2 at a relatively small angle to the axis of the filter body 2, and then extends outward for a distance at a relatively large angle to the axis of the filter body 2. The range of the relatively large angle to the axis of the filter body 2 can be set according to specific circumstances and is not specifically limited herein. For example, in some embodiments, the angle range is selected between 45° and 85°. Because the first extension portion 231 first extends a short distance from the proximal end of the filter body 2 toward the bottom of the filter body 2 at a relatively small angle, the multiple balance bars 23 converge at the proximal end of the filter body 2, thereby making the overall structure of the secondary vena cava filter more harmonious and compact, and further improving the overall stability of the secondary vena cava filter.

[0088] In some embodiments of the present invention, the second extension portion 232 is fixedly connected to the first extension portion 231 and extends a distance parallel to the axis of the filter body 2. It should be noted that the second extension portion 232 can contact the blood vessel wall, thereby providing support for the vena cava secondary filter. Because the first support portion 221 also supports the vena cava secondary filter, the combined support of the multiple second extension portions 232 and the multiple first support portions 221 can prevent the vena cava secondary filter from tilting, thereby maintaining a more stable position within the blood vessel.

[0089] In a specific implementation, multiple balance rods 23 can be symmetrically arranged along the axis of the filter body 2, so that the overall structure of the multiple second filter rods 22 is more symmetrical, preventing the vena cava secondary filter from tilting in the blood vessel, enhancing the balance of the vena cava secondary filter in the blood vessel, and further improving the stability of the vena cava secondary filter in the blood vessel.

[0090] In some embodiments of the present invention, multiple first filter rods 21, second filter rods 22 and multiple balance rods 23 can be symmetrically arranged along the axis of the filter body 2, thereby making the overall vena cava secondary filter a symmetrical structure, thereby improving the balance and stability of the vena cava secondary filter; on the other hand, multiple first anchors 212 and second anchors 223 of the vena cava secondary filter are also symmetrical structures, thereby making the vena cava secondary filter more firmly present in the blood vessel and less likely to be displaced.

[0091] Continue to refer Figure 3 In the embodiment of the present invention, the angle at which the first support portion 221 of the second filter rod 22 extends outward from the proximal end of the filter body 2 is greater than the angle at which the long rod 211 of the first filter rod 21 extends outward from the proximal end of the filter body. As a result, the first support portion 221 of the second filter rod 22 can form an arch-shaped supporting body outside the long rod 211 of the first filter rod 21, thereby effectively exerting the supporting role of the first support portion 221; on the other hand, the angle at which the first support portion 221 extends outward is greater than the angle at which the long rod 211 extends outward, which can make the cutting portion 222 of the second filter rod 22 have a larger curvature, thereby facilitating the entry and movement of the vena cava secondary filter into the sheath during transportation or recovery, reducing the resistance of the vena cava secondary filter during transportation and recovery and the risk of scraping out powder, thereby improving the recyclability and safety of the filter.

[0092] In some embodiments of the present invention, the length of the first extension portion 231 of the balance bar 23 can be set to be less than the length of the first support portion 221 of the second filter bar 22 extending outward from the proximal end of the filter body 2 to the maximum diameter of the filter body 2. It should be noted that this configuration is equivalent to setting the angle at which the first extension portion 231 of the balance bar 23 extends outward from the proximal end of the filter body 2 to be greater than the angle at which the first support portion 221 of the second filter bar 22 extends outward from the proximal end of the filter body 2. This allows the multiple balance bars 23 to better balance and stabilize the vena cava secondary filter, thereby improving the stability of the vena cava secondary filter within the blood vessel.

[0093] In a specific implementation, since the angle at which the first support portion 221 of the second filter rod 22 extends outward from the proximal end of the filter body 2 is greater than the angle at which the long rod 211 of the first filter rod 21 extends outward from the proximal end of the filter body, and the angle at which the first extension portion 231 of the balance rod 23 extends outward from the proximal end of the filter body 2 is greater than the angle at which the first support portion 221 of the second filter rod 22 extends outward from the proximal end of the filter body 2, multiple first filter rods 21, multiple second filter rods 22 and multiple balance rods 23 form a clearly layered structure, thereby giving the vena cava secondary filter a multi-layered structure, further improving the stability of the overall structure of the vena cava secondary filter.

[0094] Figure 4 A schematic structural diagram of a first anchor or a second anchor provided by an embodiment of the present invention is shown. Figure 4The first anchor 212 and the second anchor 223 serving as anchors may adopt the same structure. As an optional example, the first anchor 212 or the second anchor 22 may include: a base 203; a fixing thorn 201, which is separated and extended from the base 203; and a limiting member 202, which is separated and extended from the base 203 and has an angle with the fixing thorn 201.

[0095] In which, the base 203 can be fixedly connected to the end of the first filter rod and / or the second filter rod, and the vena cava secondary filter can be fixed on the blood vessel wall without displacement by the fixing thorn 201 piercing the blood vessel wall, and the limiting piece 202 at a certain angle to the fixing thorn 201 can prevent the fixing thorn 201 from penetrating the blood vessel wall too deeply and causing damage to the blood vessel wall. Therefore, through the mutual cooperation between the fixing thorn 201 and the limiting piece 202, on the one hand, the damage to the blood vessel wall caused by the fixing thorn 201 can be reduced, and on the other hand, it can be firmly fixed on the blood vessel wall to work safely.

[0096] Figure 5 FIG2 shows a schematic structural diagram of another first anchor or second anchor provided by an embodiment of the present invention, wherein the first anchor 212 or the second anchor 223 can also be composed of a base 203, a fixing thorn 201 and a limiter 202, but the structure and shape are different from those of the above embodiment, such as Figure 5 As shown, in a specific embodiment, the length of the stopper 202 is greater than the length of the fixing thorn 201, and the end of the stopper 202 away from the base 203 includes an extension structure that extends toward the fixing thorn 201. Thus, the fixing thorn 201 cooperates with the stopper 202 to better control the depth of penetration of the fixing thorn 201 into the blood vessel wall, further reducing damage to the blood vessel wall caused by the fixing thorn 201 penetrating too deeply.

[0097] Figure 6 FIG2 shows a structural diagram of another first anchor or second anchor provided by an embodiment of the present invention, wherein the first anchor 212 or the second anchor 223 can also be composed of a base 203, a fixing thorn 201 and a limiter 202, but the structure and shape are different from those of the above embodiments, such as Figure 6 As shown, the end of the fixing spike 201 away from the base 203 is nested within the retaining member 202. This simplifies the overall structure of the first or second anchor. In a specific implementation, the fixing spike 201, retaining member 202, and base 203 can be integrally formed, thereby reducing the risk of components of the first or second anchor falling off. Furthermore, the retaining member 202 can better control the depth of penetration of the fixing spike 201 into the vessel wall, further reducing damage to the vessel wall caused by the fixing spike 201 penetrating too deeply.

[0098] Continue to refer Figure 3 The recovery body 1 may include: a cone 11 and a hook 12, wherein the cone 11 may be fixedly connected to the filter body 2; the hook 12 may be arranged on the cone 11 and is suitable for recovering the vena cava secondary filter.

[0099] Figure 7 The schematic diagram of the partial structure of the recovery body of the vena cava secondary filter provided by the embodiment of the present invention is shown. Figure 7 The recovery body 1 is composed of a cone 11 and a hook 12. In a specific embodiment, the hook 12 is provided at the top of the cone 11, and the center is hollowed out to form a hook-shaped structure. The cone 11 and the hook 12 can be fixedly connected by welding. Due to the presence of the cone 11, the diameter of the head end of the recovery body 1 is reduced, so that the recovery body 1 can more conveniently enter the capture system catheter (not shown) during the recovery process; on the other hand, since the setting of the cone 11 has a self-centering function, during the recovery process, after the recovery body 1 contacts the capture system catheter (not shown), the center of the vena cava secondary filter and the axis of the capture system catheter can be self-aligned under the action of tension, further improving the retrievability of the vena cava secondary filter.

[0100] Figure 8 and Figure 9 The schematic diagram of the structure of another vena cava secondary filter recovery body provided by the embodiment of the present invention at different angles is shown. Figure 8 is an oblique view of the vena cava secondary filter recovery body 100, Figure 9 FIG. 1 is a side view of the vena cava secondary filter recovery body 100. Figure 8 and Figure 9 The recovery body 100 may include: two symmetrically arranged recovery parts 110, the overall outline of the recovery parts 110 is a cone-shaped structure, and the top of the cone-shaped structure is hollowed out to form a hook portion 120. In some embodiments of the present invention, the structure of the vena cava secondary filter recovery body 100 is formed by cutting the tube as a whole and then moving it toward the center. Specifically, the recovery body 100 forms two symmetrical recovery parts 110 with an overall cone-shaped outline after the tube is cut as a whole, and then the top of the cone-shaped structure is hollowed out to move toward the center to form a hook portion 120. Since the welding parts are reduced by cutting the tube as a whole, the falling of the welding parts during the recovery process can be avoided, thereby enhancing the safety of the vena cava secondary filter during the recovery process; on the other hand, since the recovery body 100 has a certain taper, the recovery body 100 can more conveniently enter the capture system catheter during the recovery process, thereby further improving the recyclability of the vena cava secondary filter.

[0101] Figure 10A schematic diagram of the structure of another recovery body provided by an embodiment of the present invention is shown. Figure 10 The recovery body 200 includes a base 210 and a bent portion 220 fixedly connected to the base 210, wherein the first end 210a of the base 210 is fixedly connected to the filter body (not marked in the figure), and the second end 210b is fixedly connected to the first end 220a of the bent portion 220; the second end 220b of the bent portion 220 extends toward the filter body and cooperates with the base 210 to form a recovery hook as a whole.

[0102] In a specific implementation, the base portion 210 and the bent portion 220 can be fixedly connected or integrally formed, and the specific method is not limited and can be selected according to specific needs. The bent portion 220 and the base portion 210 as a whole form a retrieval hook that can be matched with a capture system to retrieve the vena cava filter.

[0103] In some embodiments of the present invention, continue to refer to Figure 10 , the base 210 may include a first linear member 2101; the bending portion 220 may include a second linear member 2201, extending radially outward. In a specific implementation, the angle between the second linear member 2201 and the first linear member 2101 may range from 0 to 45 degrees, which may be selected according to the specific situation. It should be noted that since the first linear member 2101 and the second linear member 2201 are linear components, the recovery body composed of linear components has a certain fold angle. The existence of the fold angle can make it easier for the capture system to capture the recovery body, thereby further improving the retrievability of the vena cava filter.

[0104] Figure 11 A schematic diagram of the structure of another recovery body provided by an embodiment of the present invention is shown. Figure 11 ,and Figure 10 The difference between the recycling body shown is that the base 210 of the recycling body may include: a third linear member 2102; the bending portion 220 includes: a fourth linear member 2202, which is fixedly connected to the third linear member 2102 and is arranged parallel or nearly parallel to the third linear member 2102, and the spacing between the fourth linear member 2202 and the third linear member 2102 is less than a preset spacing threshold.

[0105] In a specific implementation, the preset distance threshold can be set according to actual conditions.

[0106] With the above embodiment, when the vena cava filter is captured by the capture system, the linear components arranged in parallel or nearly parallel can be more firmly matched with the capture system, and the distance between the fourth linear component 2202 and the third linear component 2102 is less than the preset distance threshold. Therefore, when the capture system captures the recovery body, the recovery body is not easy to separate from the capture system, thereby improving the success rate of the post-capture recovery operation of the vena cava filter and improving the retrievability of the vena cava filter.

[0107] In order to enable those skilled in the art to further understand the technical effects of the vena cava secondary filter provided by the embodiment of the present invention, the following description is made in conjunction with specific experimental records.

[0108] Simulation Experiment 1

[0109] Experimental topic: Testing the pushing and retrieving forces during filter delivery and retrieval; Experimental apparatus: Pushing force tester, blood vessel model;

[0110] Test samples: a certain experimental filter, as a control; the vena cava secondary filter provided in an embodiment of the present invention, as an experimental product.

[0111] Figure 12 The schematic diagram of the structure of the experimental filter used as a reference in the simulation experiment 1 in the embodiment of the present invention is shown. Figure 12 The experimental filter includes multiple filter rods 1201 and multiple balance rods 1202, and has only one filtering function.

[0112] Test steps:

[0113] 1. Connect the vascular model to the water bath circulation system of the push force tester. The circulating medium is normal saline and the temperature is set to 37°C.

[0114] 2. Delivery Simulation Test: Follow clinical procedures to release the vena cava filter into the vena cava model via the delivery system. During this process, test the force meter and record the maximum force. Perform three tests on each filter type.

[0115] 3. Retrieval Simulation Test: Follow the retrieval procedure to retrieve the vena cava filter from the vena cava model into the retrieval sheath using the capture system. During this process, test the force meter and record the maximum retrieval force. Perform the test three times for each filter.

[0116]

[0117] Table 1 Test data record of pushing force and recovery force during filter transportation and recovery

[0118] Referring to Table 1, it can be seen from the above experimental data that relative to Figure 12The vena cava filter shown, the vena cava secondary filter provided by the embodiment of the present invention can reduce the resistance during the delivery and recovery process.

[0119] Simulation Experiment 2

[0120] Experimental topic: Experiment on the ability to capture and cut blood clots;

[0121] Experimental equipment: peristaltic pump, vena cava vascular structure model;

[0122] Experimental materials: fresh porcine blood (containing 4% sodium citrate), normal saline, 100 U thrombin, 10-16 mm silicone tubing;

[0123] Test samples: a certain experimental filter as a control sample, and the vena cava secondary filter provided in an embodiment of the present invention as an experimental sample.

[0124] The structure of the experimental filter used as the control is the same as that used in the simulation experiment 1. The specific structure can be referred to Figure 12 .

[0125] Test steps:

[0126] 1. Connect the peristaltic pump to the model and turn it on. The circulating medium is normal saline and the flow rate is adjusted to 3.5 L / min to simulate the blood flow rate in the vena cava.

[0127] 2. Preparation of thrombus: Add about 2-4 mL of blood into a silicone tube, then add 0.2 mL of thrombin diluted to 0.05-0.1 U. Mix rapidly and let stand for 5 minutes to obtain thrombus.

[0128] 3. Release of the vena cava secondary filter: Release the vena cava secondary filter into the vena cava vascular model according to clinical procedures.

[0129] 4. Thrombus Capture Test: Prepared thrombi were released into the model's lower limb blood vessels through a silicone tube. The two filters were tested three times each, and their thrombus capture abilities were measured.

[0130]

[0131] Table 2 Test data record table of thrombus capture and cutting ability experiment

[0132] Figure 13 The photo shows the control sample capturing the thrombus in the simulation experiment 2, reference Figure 13 , the experimental filter can only filter the thrombus once and cannot cut it.

[0133] Figure 14 The photo shows the experimental article capturing the thrombus in the simulation experiment 2, reference Figure 14The vena cava secondary filter provided in the embodiment of the present invention as an experimental product can cut the thrombus and achieve secondary filtration of the thrombus.

[0134] Referring to Table 2, based on the experimental data above, it can be seen that the vena cava secondary filter provided by the present invention achieves the ability to capture and cut thrombi twice. Small thrombi that enter the lungs after cutting will not cause further pulmonary embolism, and large thrombi are captured again. Therefore, it can prevent large thrombi in the lower extremity veins from blocking the vena cava to a certain extent.

[0135] Although the embodiments of the present invention are disclosed above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A vena cava secondary filter, characterized in that: include: A recovery body and a filter body, wherein the recovery body and the filter body are fixedly connected and suitable for recovering the filter body; The filter body includes a plurality of first filter rods and a plurality of second filter rods; The first filter rod comprises: A long rod extending outward from the proximal end of the filter body, wherein a plurality of the long rods form a radial structure; a first anchoring piece, provided at the distal end of the long rod; The second filter rod comprises: a first supporting portion extending outward from the proximal end of the filter body to the maximum diameter of the filter body and then extending inward to support the blood vessel wall; The cutting portion has one end fixedly connected to the first supporting portion, and is curled in the opposite direction at the bottom of the filter body and extends toward the recovery body; wherein the cutting portion includes: a first cutting portion, one end fixedly connected to the first supporting portion, extending toward the bottom of the filter body, and suitable for cutting thrombus; a second cutting portion, one end fixedly connected to the first cutting portion, extending toward the bottom of the filter body, and curling in the opposite direction to extend toward the recovery body, suitable for cutting thrombus and also suitable for recovering thrombus from the recovery body to the filter body; The second anchor is provided at the end of the cutting portion facing the recovery body, and is suitable for preventing the vena cava secondary filter from being displaced toward the recovery body.

2. The vena cava secondary filter according to claim 1, characterized in that: The filter body further comprises: a plurality of balance bars; The balance bar comprises: a first extension portion extending outward from the proximal end of the filter body; The second extension portion is fixedly connected to the first extension portion and extends in a direction parallel to the axis of the filter body to form linear contact with the blood vessel wall.

3. The vena cava secondary filter according to claim 2, characterized in that: At least one of the plurality of first filter rods, the second filter rods, and the plurality of balance rods is symmetrically arranged along the axis of the filter body.

4. The vena cava secondary filter according to claim 3, characterized in that: The angle at which the first support portion of the second filter rod extends outward from the proximal end of the filter body is greater than the angle at which the long rod of the first filter rod extends outward from the proximal end of the filter body.

5. The vena cava secondary filter according to claim 4, characterized in that: The length of the first extension portion of the balance bar is smaller than the length of the first support portion of the second filter bar extending outward from the proximal end of the filter body to the maximum diameter of the filter body.

6. The vena cava secondary filter according to any one of claims 1 to 5, characterized in that: The extending direction of the first anchor is the same as the extending direction of the first filter rod; An extension direction of the second anchor is opposite to an extension direction of the first anchor.

7. The vena cava secondary filter according to claim 6, characterized in that: The first anchor and / or the second anchor comprises: base; a fixed spine extending separately from the base; A limiting member extends separately from the base and forms an angle with the fixing thorn.

8. The vena cava secondary filter according to claim 7, characterized in that: The length of the limiting member is greater than that of the fixing thorn, and one end of the limiting member away from the base includes an extension structure extending toward one side of the fixing thorn.

9. The vena cava secondary filter according to claim 7, characterized in that: One end of the fixing thorn away from the base is nested in the interior of the limiting component.

10. The vena cava secondary filter according to claim 1, characterized in that: The recyclable body comprises: A cone, fixedly connected to the filter body; The hook portion is arranged on the cone and is suitable for recovering the vena cava secondary filter.

11. The vena cava secondary filter according to claim 10, characterized in that: The hook portion is arranged on the top of the cone, and the center is hollowed out to form a hook-shaped structure.

12. The vena cava secondary filter according to claim 1, wherein: The recyclable body comprises: Two symmetrically arranged recycling pieces have an overall outline of a cone-shaped structure, and a hook portion is hollowed out at the top of the cone-shaped structure.

13. The vena cava secondary filter according to claim 1, wherein: The recovery body includes a base and a bending portion fixedly connected to the base, wherein: The base portion has a first end fixedly connected to the filter body, and a second end fixedly connected to the first end of the bent portion; The second end of the bent portion extends toward the filter body and forms a recovery hook integrally with the base.

14. The vena cava secondary filter according to claim 13, characterized in that: The base includes a first linear member; The bending portion includes a second linear member extending radially outward, and an angle between the second linear member and the first linear member is in a range of 0 to 45 degrees.

15. The vena cava secondary filter according to claim 13, wherein: The base includes: a third linear member; The bending portion includes: a fourth linear member, which is fixedly connected to the third linear member and arranged in parallel or nearly parallel to the third linear member, and a distance between the fourth linear member and the third linear member is less than a preset distance threshold.

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