CN115040287A - Secondary filter for vena cava - Google Patents

Abstract

A vena cava secondary filter, comprising: the recovery body is fixedly connected with the filtering body and is suitable for recovering the filtering body; the filter body comprises a plurality of first filter rods and a plurality of second filter rods; the first filter rod includes: the long rods extend outwards from the near end of the filter body, and the long rods form a radial structure; the first anchoring piece is arranged at the far end of the long rod; the second filter rod includes: a first support portion extending outwardly from the proximal end of the filter body to a maximum diameter of the filter body and extending inwardly to support the vessel wall; a cutting part, one end of which is fixedly connected with the first supporting part and is reversely curled at the bottom of the filter body to extend towards the direction of the recovery body; and a second anchor provided at an end of the cutting section in a direction toward the recovery body. The vena cava secondary filter can reduce the resistance of the vena cava secondary filter in the conveying and recovering process, and can perform secondary filtration and cutting on thrombus formed in the vena cava.

Description

Secondary filter for vena cava

Technical Field

The embodiment of the invention relates to the technical field of medical instruments, in particular to a vena cava secondary filter.

Background

Pulmonary artery Embolism (PE) and Deep Vein Thrombosis (DVT) are collectively referred to as Venous Thromboembolism (VTE). It is estimated that the incidence of VTE is the third most common vascular disease in vascular diseases, following acute coronary syndrome and stroke. Because of the lack of specific clinical manifestations, the misdiagnosis and missed diagnosis rate are high, which is now an important cause of death of people.

The Vena Cava Filter (VCF) is a filtering device designed for preventing pulmonary artery embolism (PE) caused by the shedding of emboli of the superior and inferior Vena Cava systems. Since the filter is applied clinically for the first time in the early 1967, the vein filter has developed various products with various types and structures to enter the clinic after more than 50 years of continuous improvement and innovation. Currently, there are major classifications of permanent filters and non-permanent filters.

The permanent filter is suitable for the old VTE patients with the diseases (such as thrombosis and immune diseases) which clearly cause the VTE and are difficult to relieve in a short term, long-term anticoagulation contraindications (such as hemophilia) and the VTE patients with neoplastic diseases and short expected survival time. Research has proved that the filter can effectively reduce the incidence rate of PE after being implanted, but the long-term implantation in vivo can cause complications such as inferior vena cava perforation, filter displacement, inferior vena cava occlusion caused by secondary thrombus, DVT recurrence and the like, thereby limiting the popularization of the filter.

The semipermanent filter is a new product aiming at replacing the permanent filter, mainly comprising a recyclable filter and a temporary filter. The temporary filter has more complications (such as infection, filter displacement, breakage and the like) after being placed, and the recyclable filter also has some clinical application difficulties, but the development of the filter is a main direction.

The key point of the recoverable filter optimizes the concept of "recoverable". Mainly comprises the following steps:

1. the recoverable time window is extended. At present, the time window of most recyclable filters allowed to be placed in the body is very short, often 2-3 weeks, VTE risks or anticoagulation contraindications of many patients are not completely eliminated in the period, the filter placement time has to be prolonged, and once the time window is exceeded, the filter is difficult to take out due to problems of thrombosis, intimation and the like, so that the filter becomes a permanent filter to be placed in the body, and a series of problems faced after the permanent filter is placed are faced;

2. the extraction rate is improved. The design is improved in structure, operability, etc., and the filter extraction rate is increased. The ability of the filter to resist tipping, perforation, displacement, etc. is increased primarily in terms of stability.

Fig. 1 is a vena cava filter of the prior art, and referring to fig. 1, the vena cava filter comprises a first filter portion 1100 and a second filter portion 1200 with opposite openings; the first filter part 1100 is formed by extending outwards from the center in a forward direction step by step and turning and curling in a reverse direction step by step, and the first filter part 1100 is supported on the inner wall of the blood vessel; the second filter portion 1200 is formed by extending outward gradually from the center forward direction; the first filter portion 1100 is provided with anchoring barbs 1300 extending in the opposite direction for anchoring on the inner wall of the blood vessel, and the second filter portion 1200 is provided with anchoring barbs 1400 extending in the forward direction for anchoring on the inner wall of the blood vessel. The first filtering part 1100 of the vena cava filter, which comprises the anchor thorn 1300, has the advantages of small integral bending radius, large angle, high rigidity, high resistance during sheath recovery, and easy clamping on the outer wall of a sheath tube to increase the recovery difficulty; meanwhile, the vena cava filter can only carry out one-time filtration, has no function of cutting thrombus, and is easy to cause pulmonary embolism and the vena cava is blocked by thrombus with large lower limb vein because the thrombus with the diameter of more than 1cm can cause pulmonary embolism clinically.

Disclosure of Invention

In view of the above, the present invention provides a secondary vena cava filter, which can reduce resistance during delivery and recovery, and perform secondary filtration and cutting on thrombus formed in the vena cava.

The embodiment of the invention provides a vena cava secondary filter, which comprises: the recovery body is fixedly connected with the filtering body and is suitable for recovering the filtering body; the filter body comprises a plurality of first filter rods and a plurality of second filter rods; the first filter rod includes: the long rod extends outwards from the near end of the filter body, and a plurality of long rods form a radial structure; the first anchoring piece is arranged at the far end of the long rod; the second filter rod includes: a first support portion extending outwardly from a proximal end of the filter body to a maximum diameter of the filter body and extending inwardly to support a vessel wall; a cutting part, one end of which is fixedly connected with the first supporting part and is reversely curled at the bottom of the filter body to extend towards the direction of the recovery body; and a second anchor provided at an end of the cutting portion in a direction toward the recovery body.

Optionally, the cutting portion comprises: one end of the first cutting part is fixedly connected with the first supporting part, extends towards the bottom of the filter body and is suitable for cutting thrombus; and one end of the second cutting part is fixedly connected with the first cutting part, extends to the bottom of the filter body, is reversely curled and extends towards the direction of the recovery body, and is suitable for cutting thrombus.

Optionally, the filter body further comprises: a plurality of balance bars; the balance bar includes: a first extension extending outwardly from a proximal end of the filter body; and the second extension part is fixedly connected with the first extension part and extends along the direction parallel to the axis of the filter body so as to form line contact with the blood vessel wall.

Optionally, at least one of the first filter rod, the second filter rod and the balance rod is arranged symmetrically along the axis of the filter body.

Optionally, the angle at which the first support portion of the second filter rod extends outwardly from the proximal end of the filter body is greater than the angle at which the elongate rod of the first filter rod extends outwardly from the proximal end of the filter body.

Optionally, the length of the first extension of the balance bar is less than the length of the first support portion of the second filter rod extending outwardly from the proximal end of the filter body to the maximum diameter of the filter body.

Optionally, the extension direction of the first anchor is the same as the extension direction of the first filter rod; the second anchor extends in a direction opposite to the direction in which the first anchor extends.

Optionally, the first and/or second anchors comprise: a base; a fixed thorn, which is separated and extends from the base; the limiting piece is separated and extends out from the base and forms an included angle with the fixed thorn.

Optionally, the length of the limiting member is greater than that of the fixing spine, and one end of the limiting member away from the base portion includes an extending structure extending toward one side of the fixing spine.

Optionally, one end of the fixing thorn, which is far away from the base, is nested inside the limiting piece.

Optionally, the recovery body comprises: the cone is fixedly connected with the filter body; and the hook part is arranged on the cone and is suitable for recovering the vena cava secondary filter.

Optionally, the hook part is arranged at the top of the cone, and the center of the hook part is hollowed to form a hook-shaped structure.

Optionally, the recovery body comprises: the novel garbage recycling device comprises two recycling pieces which are symmetrically arranged, wherein the whole outline of each recycling piece is of a conical structure, and the top of each conical structure is hollowed to form a hook part.

Optionally, the recovery body comprises a base portion and a bent portion fixedly connected with the base portion, wherein:

the first end of the base part is fixedly connected with the filter body, and the second end of the base part is fixedly connected with the first end of the bent part;

the second end of the bending part extends towards the direction of the filter body and forms a recovery hook with the base part.

Optionally, the base comprises a first linear member; the kink includes: and the second linear piece extends outwards along the radial direction, and the angle between the second linear piece and the first linear piece ranges from 0 degree to 45 degrees.

Optionally, the base comprises: a third linear element; the kink includes: and the fourth linear piece is fixedly connected with the third linear piece, is arranged in parallel or nearly in parallel, and has a distance smaller than a preset distance threshold value with the third linear piece.

By adopting the scheme of the embodiment of the invention, the filter body comprises a plurality of first filter rods and a plurality of second filter rods, wherein each second filter rod comprises a cutting part, one end of each cutting part is fixedly connected with the corresponding first supporting part, the bottom of each filter body is reversely curled and extends towards the direction of the corresponding recovery body, and a second anchoring part is arranged at the end part of each cutting part towards the direction of the corresponding recovery body; and because the first filter rod comprises long rods which extend outwards from the near end of the filter body, and the long rods form a radial structure, thrombus cut and filtered by the cutting part can be filtered for the second time, so that the vena cava secondary filter can reduce the resistance in the conveying and recovering processes, and has the functions of filtering and cutting thrombus formed in the vena cava for the second time.

Furthermore, a plurality of balance rods are arranged on the vena cava secondary filter, so that the balance performance of the vena cava secondary filter in a blood vessel can be enhanced, the vena cava secondary filter is prevented from being inclined in the blood vessel, and the stability of the vena cava secondary filter in the blood vessel is improved.

Furthermore, at least one of the first filter rod, the second filter rod and the balance rods is arranged symmetrically along the axis of the filter body, so that the overall balance of the vena cava secondary filter is further enhanced, and the stability of the vena cava secondary filter in a blood vessel is improved.

Furthermore, the angle of the first supporting part of the second filter rod extending outwards from the near end of the filter body is larger than the angle of the long rod of the first filter rod extending outwards from the near end of the filter body, so that the structures of the first filter rod and the second filter rod are more stable, the working fit between the first filter rod and the second filter rod is facilitated, and the stability of the overall structure of the vena cava secondary filter is further improved.

Furthermore, the length of the first extending part of the balance rod is smaller than the length of the first supporting part of the second filter rod extending outwards from the near end of the filter body to the maximum diameter of the filter body, so that the overall structure of the balance body is more stable, the balance and stable effect of the balance body is better exerted, and the overall stability of the vena cava secondary filter is further improved.

Further, by providing the first anchoring member to extend in the same direction as the first filter rod and the second anchoring member to extend in the opposite direction to the first anchoring member, the second vena cava filter can be prevented from being displaced or displaced when the vena cava filter is subjected to stresses from different directions in a blood vessel.

Furthermore, by arranging the first anchoring piece and/or the second anchoring piece to comprise a base part, a fixing thorn which is separated and extended from the base part and a limiting part which is separated and extended from the base part and forms an included angle with the fixing thorn, on one hand, the vena cava secondary filter can be more stably fixed on a blood vessel wall through the fixing thorn, and the stability of the vena cava secondary filter in the blood vessel is improved; on the other hand, the limiting piece has a certain limiting effect on the depth of the fixed stabbed blood vessel, so that the depth of the fixed stabbed blood vessel can be prevented from being too deep, and the possibility that the fixed stabbed blood vessel is damaged due to the fact that the fixed stabbed blood vessel is pierced is avoided.

Furthermore, the length of the limiting part is larger than that of the fixed thorn, and one end, far away from the base part, of the limiting part comprises an extension structure extending towards one side of the fixed thorn, so that the limiting part can better play a role in limiting the depth of the fixed thorn penetrating into the blood vessel, and the possibility that the fixed thorn is damaged by penetrating into the blood vessel deeply is better avoided.

Furthermore, one end of the fixing thorn, which is far away from the base, is arranged in the limiting piece in a nested manner, so that the structure of the first anchoring piece and/or the second anchoring piece is simpler, the structural design of the first anchoring piece and/or the second anchoring piece is optimized, and the risk of falling off of the components is reduced; on the other hand, the limiting piece can limit the depth of the fixed puncture into the blood vessel, so that the damage to the blood vessel caused by the deep depth of the fixed puncture into the blood vessel is reduced.

Furthermore, the recycling body comprises a cone fixedly connected with the filter body, so that the recycling body has a certain taper integrally, the diameter size of the head end of the recycling body is reduced, and the vena cava secondary filter is convenient to be caught by a catheter of a catching system in the recycling process; on the other hand, the cone has a self-centering function, and in the recovery process, after the hook part is connected with the catheter of the capturing system, the center of the recovery body can be automatically aligned with the axis of the catheter of the capturing system under the action of pulling force, so that the vena cava secondary filter can conveniently and stably enter the sheath tube in the recovery process, and the recoverability of the vena cava secondary filter is improved.

Furthermore, the hook part is arranged at the top of the cone, and the center of the cone is hollowed to form a hook-shaped structure, so that the vena cava secondary filter can be caught by a catheter of a catching system more conveniently in the recycling process, and the recyclability of the vena cava secondary filter is further improved.

Furthermore, through setting up the recovery body includes the recovery piece of two symmetry settings, the overall profile of recovery piece is the cone structure, and the top fretwork of cone structure forms hook portion, and the fault-tolerant rate of being arrested by capture system's pipe at the in-process of retrieving can be improved to the recovery piece that the symmetry set up in one side, and on the other hand, because the overall profile of recovery piece is the cone structure to make the recovery piece have certain tapering, and then reduced recovery body head end diameter size, make vena cava secondary filter be convenient for more by capture system's pipe capture at the in-process of retrieving.

Further, by arranging the base part of the recovery body with the first end fixedly connected with the filter body and the second end fixedly connected with the first end of the bending part, the second end of the bending part of the recovery body extends towards the direction of the filter body, and the recovery hook is integrally formed with the base part, the recovery hook can be more easily caught by the catching system, and the recoverability of the vena cava filter is improved.

Furthermore, the second linear piece provided with the bending part extends outwards along the radial direction, and the angle range between the second linear piece and the first linear piece is 0-45 degrees, so that the vena cava filter is not easy to separate when being caught by a catching system, the catching success rate of the vena cava filter is improved, and the recoverability of the vena cava filter is further improved.

Furthermore, through setting up the fourth linear member of kink with third linear member fixed connection, and with third linear member is parallel or nearly parallel arrangement, with the interval of third linear member is less than predetermineeing interval threshold value, thereby makes the vena cava filter is difficult for breaking away from when being arrested by the capture system, and then has improved the capture success rate of vena cava filter, further improves the recyclability of vena cava filter.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 shows a schematic diagram of a vena cava filter of the prior art;

FIG. 2 is a schematic diagram illustrating a vena cava secondary filter according to an embodiment of the present invention;

FIG. 3 is a schematic diagram illustrating another vena cava secondary filter according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a first anchor or a second anchor according to an embodiment of the present invention;

fig. 5 is a schematic structural diagram of another first anchor or second anchor provided by the embodiment of the invention;

fig. 6 is a schematic structural diagram of a first anchor or a second anchor according to another embodiment of the present invention;

FIG. 7 is a partial schematic view showing the structure of a recovery body of a vena cava secondary filter according to an embodiment of the present invention;

FIGS. 8 and 9 are schematic diagrams showing different angles of another vena cava secondary filter retriever provided by embodiments of the present invention;

FIG. 10 is a schematic view showing the structure of another recycling body provided in the embodiment of the present invention;

FIG. 11 is a schematic structural diagram of a recycling body according to another embodiment of the present invention;

FIG. 12 shows a schematic diagram of the structure of an experimental filter as a control of simulation experiment 1 in an example of the present invention;

FIG. 13 is a photograph showing the capture of thrombus by a control of simulation experiment 2 in the example of the present invention;

fig. 14 is a photograph showing thrombus capture by an experimental article of simulation experiment 2 in the example of the present invention.

Detailed Description

In order to make the aforementioned objects, features and advantages of the embodiments of the present invention comprehensible, specific embodiments accompanied with figures are described in detail below.

Fig. 2 is a schematic structural diagram of a vena cava secondary filter provided by an embodiment of the present invention, and referring to fig. 2, the vena cava secondary filter comprises: the recovery body 1 and the filter body 2 are fixedly connected, and the recovery body 1 and the filter body 2 are suitable for recovering the filter body 2; the filter body 2 comprises a plurality of first filter rods 21 and a plurality of second filter rods 22.

Wherein the first filter rod 21 may include: an elongated rod 211 extending outwardly from the proximal end of the filter body 2, wherein a plurality of the elongated rods 211 form a radial structure; a first anchor 212 disposed at a distal end of the long rod 211; the second filter rod 22 may include: a first support part 221 extending from the proximal end of the filter body 2 to the maximum diameter of the filter body 2 and extending inward to support the vessel wall; a cutting part 222, one end of which is fixedly connected with the first supporting part 221 and is reversely curled at the bottom of the filter body 2 to extend towards the direction of the recovery body 1; and a second anchor 223 provided at an end of the cutting part 222 in a direction toward the recovery body 1.

In the embodiment of the invention, the vena cava secondary filter comprises a recovery body 1 and a filter body 2, wherein the recovery body 1 and the filter body 2 are fixedly connected, and a welded fixed connection mode can be particularly adopted. The recovery body 1 can be docked with a filter catching means and temporarily connected to the filter catching means, so that the filter catching means can be operated and the filter body 2 can be recovered by the recovery body 1.

With continued reference to fig. 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. Wherein, a plurality of the first filter rods 21 and a plurality of the second filter rods 22 are formed by extending the proximal end of the filter body 2 outwards. The proximal end of the filter body 2 is the place of connection between the filter body 2 and the recovery body 1.

In a specific embodiment, the material used for the filter body 2 may be a shape memory alloy, such as nitinol.

In the embodiment of the present invention, the first filtering rod 21 may be a long rod 211, which has a relatively long size as the name implies. In a specific implementation, the number of the plurality of long rods 211 may be selected according to actual conditions, and is not specifically limited herein, for example, in some embodiments, the number of the plurality of long rods 211 may be selected in a range of 2 to 6 according to actual conditions. As shown in fig. 2, in the embodiment of the present invention, the number of the plurality of long bars 211 is 4.

In a specific implementation, the plurality of long rods 211 extend outward from the proximal end of the filter body 2 to form a radial structure, and specifically, the plurality of long rods 211 extend a short distance from the proximal end of the filter body 2 to a direction parallel to the axis of the filter body 2, and then extend straight to a direction forming a certain angle with the axis of the filter body 2. The angle between the long rods 211 and the axis of the filter body 2 can be selected according to the actual situation, for example, can be selected between 20 ° and 45 °, and is not limited specifically herein. Specifically speaking, the head ends of the long rods 211 and the small distance parallel to the axis of the filter body 2 can make the long rods 211 shrink at the near end of the filter body 2, so that the overall structure of the vena cava secondary filter is harmonious and smooth, and the stability of the overall structure of the vena cava secondary filter is improved.

In some embodiments of the present invention, the first filter rod 21 may further include a first anchoring member 212 which may be disposed at a distal end of the long rod 211, wherein the first anchoring member 212 may fix the vena cava secondary filter in the blood vessel and may make the vena cava secondary filter cope with stress from the direction from the recovery body 1 to the filter body 2 in the blood vessel, so that the vena cava secondary filter may be prevented from being displaced toward the filter body 2.

In a specific implementation, a plurality of the first filter rods 21 may be symmetrically disposed along the axis of the filter body 2, specifically, when a plurality of the first filter rods 21 are symmetrically disposed along the axis of the filter body 2, the axis of the radial structure formed by the plurality of long rods 211 coincides with the axis of the filter body 2, so that a plurality of the first filter rods 21 are more symmetrical structurally, and thus a plurality of the first anchors 212 may be anchored on the blood vessel wall more symmetrically and firmly, thereby improving the stability of the vena cava secondary filter in the blood vessel as much as possible.

With continued reference to fig. 2, in some embodiments of the invention, the second filter rod 22 may be comprised of a first support portion 221 and a cutting portion 222. The first supporting portion 221 and the cutting portion 222 may be fixedly connected, or may be integrally formed, and may be selected according to actual requirements.

In a specific implementation, the number of the second filter rods 22 can be selected according to actual situations, and is not limited in particular. For example, in some embodiments, the number of the second filter rods 22 may be selected from 2 to 6 according to practical situations. In one embodiment, as shown in fig. 2, the number of the second filter rods 22 is 4, and the number of the plurality of second filter rods 22 in fig. 2 is shown as 2, actually 4, for the sake of viewing angle.

In some embodiments of the present invention, the first supporting portion 221 may extend from the proximal end of the filter body 2 to the maximum diameter of the filter body 2. Specifically, the position of the maximum diameter of the filter body 2 is the outermost position of the side edge of the filter body 2, and the first supporting part 221 forms a supporting structure similar to an arch at the maximum diameter of the filter body 2, so that the first supporting part 221 forms a point contact with the wall of the blood vessel in the blood vessel, and the first supporting part 221 plays a role of supporting the vena cava secondary filter, so that the vena cava secondary filter can be stably present in the blood vessel, and the stability of the vena cava secondary filter is improved.

It should be noted that the first supporting portion 221 extends from the proximal end of the filter body 2 to the maximum diameter of the filter body 2, and may continue to extend for a short distance in a direction parallel to the axis of the filter body 2 and then extend inward. In this way, the first support part 221 is in line contact with the blood vessel wall in the blood vessel, so that the first support part 221 can better play a role of supporting, the vena cava secondary filter can be more stably present in the blood vessel, and the stability of the vena cava secondary filter is further improved.

In some embodiments of the invention, the cut portion 222 of the second filter rod 22 is reversely curled at the bottom of the filter body 2 to extend in a direction toward the recovery body 1. Specifically, the cutting portion 222 may continue to extend toward the bottom of the filter body 2 in the extending direction of the first support portion 221, and may be reversely curled at the bottom of the filter body 2. The cutting portions 222 of the plurality of second filter rods 22 are respectively curled and extended in a direction opposite to the direction of the recovering body 1 after meeting at the bottom of the filter body 2, thereby forming a primary filtering structure at the bottom of the filter body 2; meanwhile, due to the structural arrangement of the cutting parts 222 of the plurality of second filter rods 22, a thrombus with a larger volume can be cut, so that the thrombus with the larger volume is divided into a plurality of thrombus with smaller volume after being cut.

In a specific implementation, since the plurality of first filtering rods 21 are composed of a plurality of long rods 211, and the plurality of long rods 211 are in a radial structure towards the bottom of the filtering body 2, the filtering structure formed by the plurality of first filtering rods 21 can recover thrombus from the filtering body 2 to the recovering body 1; since the cutting portions 222 of the plurality of second filter rods 22 are reversely curled at the bottom of the filter body 2 and extend in the direction of the restoration body 1, the thrombus in the direction from the restoration body 1 to the filter body 2 can be restored by the filter structure formed by the cutting portions 222 of the plurality of second filter rods 22; meanwhile, the thrombus with smaller volume cut by the cutting part 222 can be accommodated, so that the secondary filtration is realized.

It is understood that the vena cava secondary filter, by setting the plurality of long rods 211 and the plurality of cutting portions 222, on the one hand, can achieve the function of recovering thrombus in both directions, i.e., the vena cava secondary filter can recover thrombus in the direction from the filtering body 2 to the recovering body 1 and in the direction from the recovering body 1 to the filtering body 2; on the other hand, can cut and secondary filter the thrombus of great volume, consequently can avoid lower limbs vein thrombosis to a certain extent to block up vena cava. In conclusion, the secondary filtering function of the vena cava secondary filter can be further improved by the arrangement that the plurality of cutting portions 222 are reversely curled at the bottom of the filter body 2.

In some embodiments of the present invention, a second anchor 223 may be provided at an end of the cutting part 222 facing the direction of the recovery body 1, wherein the second anchor 223 may fix the vena cava secondary filter in the blood vessel and may allow the vena cava secondary filter to cope with 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 in the direction of the recovery body 1.

In order to further realize the cutting function of the vena cava secondary filter, the cutting part can be set to comprise a plurality of cutting parts with different shapes. The following description is made with reference to the accompanying drawings.

With continued reference to fig. 2, the cutting 222 may include: a first cutting part 2221 and a second cutting part 2222, wherein: one end of the first cutting portion 2221 is fixedly connected to the first support portion 221, extends toward the bottom of the filter body 2, and is adapted to cut thrombus; and a second cutting part 2222 having one end fixedly connected to the first cutting part 2221, extending toward the bottom of the filter body 2, and curling in the opposite direction toward the recovery body 1, and adapted to cut the thrombus.

In a specific embodiment, the first cutting portion 2221 may have various shapes, for example, a straight shape or a shape with a certain arc. As a specific example, as shown in fig. 2, the first cutting portion 2221 has a straight line shape suitable for cutting a thrombus.

In some embodiments of the present invention, the second cutting portion 2222 is in a curled shape and has a larger curvature, first, the second cutting portion 2222 can cut the thrombus, second, the second cutting portion 2222 with a larger curvature can reduce the resistance in the process of delivering and recovering the vena cava secondary filter, and finally, the second cutting portion 2222 can recover the thrombus from the recovering body 1 to the filtering body 2, thereby achieving bidirectional recovery of the thrombus.

In specific implementation, since the first anchoring member 212 can prevent the vena cava secondary filter from displacing towards the filter body 2 and the second anchoring member 223 can prevent the vena cava secondary filter from displacing towards the recovery body 1, the vena cava secondary filter can realize bidirectional displacement prevention through the first anchoring member 212 and the second anchoring member 223, so that the vena cava secondary filter can exist in a blood vessel more stably, and the stability of the vena cava secondary filter is further improved.

In particular implementations, as shown in fig. 2, the first anchor 212 may extend in the same direction as the first filter rod 21; the second anchor 223 may extend in a direction opposite to the first anchor 212, so that the vena cava secondary filter can more stably cope with stresses from different directions in the blood vessel, thereby better performing a bidirectional displacement prevention function.

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

In the embodiment of the present invention, since the second anchoring member 223 and the cutting portion 222 are reversely curled at the bottom of the filter body 2 as a whole and have a large curvature, it is advantageous for the vena cava secondary filter to enter and move in the sheath during the transportation or recovery process, so that the resistance and the risk of scraping off dusts during the transportation and recovery process of the vena cava secondary filter can be reduced, and the recoverability of the vena cava secondary filter can be further improved.

Fig. 3 shows a schematic structural diagram of another vena cava secondary filter provided by an embodiment of the present invention, and referring to fig. 3, the difference from the vena cava secondary filter shown in fig. 2 is that the filter body 2 further comprises: a plurality of balance bars 23. Wherein the balance bar 23 may include: a first extension 231 extending outwardly from a proximal end of the filter body 2; and a second extension 232 fixedly connected to the first extension 231 and extending in a direction parallel to the axis of the filter body 2 to make line contact with the wall of the blood vessel.

In the embodiment of the present invention, the number of the balance bars 23 may be selected according to actual conditions, and is not specifically limited herein, for example, in some embodiments, the number of the balance bars 23 may be selected in a range of 4 to 8 according to actual conditions. As an alternative example, the number of said balancing bars 23 is 4, as shown in figure 3.

With continued reference to fig. 3, the balance bar 23 is composed of a first extension 231 and a second extension 232, in a specific implementation, the connection manner between the first extension 231 and the second extension 232 may be a fixed connection, such as a welding manner, or may be an integral formation of the two, and the specific connection manner may be selected according to the actual situation.

In some embodiments of the present invention, the first extension 231 first extends from the proximal end of the filter body 2 to the bottom of the filter body 2 at a small angle with respect to the axis of the filter body 2 for a short distance, and then extends outward at a large angle with respect to the axis of the filter body 2 for a short distance, wherein the range of the large angle with respect to the axis of the filter body 2 can be set according to specific situations, and is not particularly limited herein, for example, in some embodiments, the range of the angle is selected from 45 ° to 85 °. Since the first extension 231 first extends from the proximal end of the filter body 2 to the bottom of the filter body 2 at a small angle for a short distance, the balance rods 23 are contracted at the proximal end of the filter body 2, and the overall structure of the vena cava secondary filter is more harmonious and compact, thereby further improving the stability of the overall structure of the vena cava secondary filter.

In some embodiments of the present invention, the second extension 232 is fixedly connected to the first extension 231 and extends for a distance in a direction parallel to the axis of the filter body 2. It should be noted that the second extension 232 can be in line contact with the wall of the blood vessel, thus supporting the vena cava secondary filter. Since the first support part 221 can also support the vena cava secondary filter, the vena cava secondary filter is less likely to be inclined by the supporting effect of the plurality of second extension parts 232 and the plurality of first support parts 221, and thus can be more stably present in the blood vessel.

In a specific implementation, a plurality of the balance rods 23 can be symmetrically arranged along the axis of the filter body 2, so that the overall structure of the second filter rods 22 is more symmetrical, the inclination of the vena cava secondary filter in a blood vessel is prevented, the balance of the vena cava secondary filter in the blood vessel is enhanced, and the stability of the vena cava secondary filter in the blood vessel is further improved.

In some embodiments of the present invention, a plurality of the first filter rods 21, the second filter rods 22 and a plurality of the balance rods 23 may be symmetrically disposed along the axis of the filter body 2, so that the vena cava secondary filter has a symmetrical structure as a whole, thereby improving the balance and stability of the vena cava secondary filter; on the other hand, the plurality of first anchors 212 and the second anchors 223 of the vena cava secondary filter are also of a symmetrical structure, so that the vena cava secondary filter is more stably positioned in the blood vessel and is not easy to displace.

With continued reference to fig. 3, in the embodiment of the present invention, the angle at which the first supporting 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, so that the first supporting portion 221 of the second filter rod 22 can form an arch-like supporting main body outside the long rod 211 of the first filter rod 21, and thus the supporting function of the first supporting portion 221 can be effectively exerted; on the other hand, the angle of outward extension of the first supporting part 221 is greater than the angle of outward extension of the long rod 211, so that the cutting part 222 of the second filter rod 22 has a larger bending curvature, and thus the vena cava secondary filter can enter the sheath tube and move in the sheath tube during the conveying or recovering process, the resistance of the vena cava secondary filter during the conveying and recovering process and the risk of scraping off dusts are reduced, and the recyclability and the use safety of the filter are improved.

In some embodiments of the present invention, the length of the first extension 231 of the balancing bar 23 may be set to be smaller than the length of the first support part 221 of the second filter rod 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 the above arrangement is equivalent to setting the angle at which the first extension 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. Therefore, the balance rods 23 can better perform the balance and stabilization functions, and the stability of the vena cava secondary filter in the blood vessel is improved.

In specific implementation, since the angle at which the first supporting 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 extending portion 231 of the balancing rod 23 extends outward from the proximal end of the filter body 2 is greater than the angle at which the first supporting portion 221 of the second filter rod 22 extends outward from the proximal end of the filter body 2, the plurality of first filter rods 21, the plurality of second filter rods 22, and the plurality of balancing rods 23 are well-defined structures, so that the vena cava secondary filter has a multi-layer structure, and the stability of the overall structure of the vena cava secondary filter is further improved.

Fig. 4 shows a schematic structural diagram of a first anchor or a second anchor according to an embodiment of the present invention, and referring to fig. 4, the first anchor 212 and the second anchor 223 as anchors may adopt the same structure, and as an alternative example, the first anchor 212 or the second anchor 22 may include: a base 203; a fixed barb 201 extending away from the base 203; the limiting member 202 extends from the base 203 and forms an included angle with the fixing spine 201.

The base 203 can be fixedly connected with the end of the first filter rod and/or the second filter rod, the vena cava secondary filter can be fixed on the blood vessel wall without displacement by pricking the fixed thorn 201 into the blood vessel wall, and the limiting piece 202 with a certain included angle with the fixed thorn 201 can prevent the fixed thorn 201 from pricking the blood vessel wall deeply and damaging the blood vessel wall, so that the damage of the fixed thorn 201 to the blood vessel wall can be reduced through the mutual matching between the fixed thorn 201 and the limiting piece 202, and the other hand can work stably and safely on the blood vessel wall.

Fig. 5 shows a structural schematic view of another first anchor or second anchor according to an embodiment of the present invention, wherein the first anchor 212 or second anchor 223 may also include a base 203, a fixing spike 201, and a limiting member 202, but the structure and shape are different from those of the previous embodiments, as shown in fig. 5, in a specific implementation, the length of the limiting member 202 is greater than that of the fixing spike 201, and an end of the limiting member 202 away from the base 203 includes an extending structure extending toward a side of the fixing spike 201. Therefore, the fixing pricks 201 are matched with the limiting pieces 202, the depth of the fixing pricks 201 penetrating into the blood vessel wall can be better controlled, and the damage to the blood vessel wall caused by the fact that the fixing pricks 201 penetrate into the blood vessel wall deeply is further reduced.

Fig. 6 shows a structural schematic view of another first anchor or second anchor according to an embodiment of the present invention, wherein the first anchor 212 or second anchor 223 may also be composed of a base 203, a fixing spike 201, and a limiting member 202, but the structure and shape are different from those of the previous embodiments, as shown in fig. 6, one end of the fixing spike 201 away from the base 203 is nested inside the limiting member 202. Therefore, the overall structure of the first anchoring piece or the second anchoring piece can be simpler, and in specific implementation, the fixing thorn 201, the limiting piece 202 and the base part 203 can be integrally formed, so that the risk that the first anchoring piece or the second anchoring piece falls off can be reduced; on the other hand, the stopper 202 can better control the depth of the fixing spike 201 penetrating into the blood vessel wall, and further reduce the damage to the blood vessel wall caused by the deep penetration of the fixing spike 201 into the blood vessel wall.

With continued reference to fig. 3, the recovery body 1 may comprise: a cone 11 and a hook 12, wherein the cone 11 can be fixedly connected with the filter body 2; the hook 12, which may be arranged on the cone 11, is adapted to retrieve the vena cava secondary filter.

Fig. 7 shows a partial structural schematic diagram of a recycling body of a vena cava secondary filter provided by an embodiment of the present invention, referring to fig. 7, a recycling body 1 is composed of a cone 11 and a hook 12, in a specific implementation, the hook 12 is arranged on the top of the cone 11, and the center of the hook is hollowed to form a hook structure, and the cone 11 and the hook 12 can be fixedly connected by welding. Due to the cone 11, the diameter size of the head end of the recovery body 1 is reduced, so that the recovery body 1 can enter a catching system pipe (not shown) more conveniently during the recovery process; on the other hand, the cone 11 is set to have a self-centering function, so that the self-alignment of the center of the vena cava secondary filter and the axis of the capturing system catheter can be realized under the action of a pulling force after the recovery body 1 is contacted with the capturing system catheter (not shown) in the recovery process, and the recoverability of the vena cava secondary filter is further improved.

Fig. 8 and 9 are schematic diagrams illustrating different angles of the vena cava secondary filter recovery body according to another embodiment of the present invention, wherein fig. 8 is an oblique view of the vena cava secondary filter recovery body 100, and fig. 9 is a side view of the vena cava secondary filter recovery body 100. Referring to fig. 8 and 9, the recovery body 100 may include: the recovery piece 110 is symmetrically arranged, the overall contour of the recovery piece 110 is a cone-shaped structure, and a hook part 120 is hollowed at the top of the cone-shaped structure. In some embodiments of the present invention, the structure of the vena cava secondary filter recovery body 100 is formed by integrally cutting a tube and then closing the tube to the center, specifically, the recovery body 100 forms two symmetrical recovery members 110 with an overall contour of a cone-shaped structure after integrally cutting the tube, and then closes the tube to the center and hollows out the top of the cone-shaped structure to form the hook 120. Because the welding parts are reduced by integrally cutting the pipe, the welding parts can be prevented from falling off in the recovery process, and the safety of the vena cava secondary filter in the recovery process is enhanced; on the other hand, the recovery body 100 has a certain taper, so that the recovery body 100 can enter the catheter of the capturing system more conveniently during the recovery process, thereby further improving the recoverability of the vena cava secondary filter.

Fig. 10 shows a schematic structural diagram of another recycling body according to an embodiment of the present invention, referring to fig. 10, the recycling body 200 includes a base portion 210 and a bending portion 220 fixedly connected to the base portion 210, wherein a first end 210a of the base portion 210 is fixedly connected to the filter (not shown) and a second end 210b of the base portion is fixedly connected to a first end 220a of the bending portion 220; the second end 220b of the bending part 220 extends toward the filter body, and is engaged with the base part 210 to form a recycling hook.

In a specific implementation, the base portion 210 and the bending portion 220 may be fixedly connected or integrally formed, and a specific manner is not limited and may be selected according to specific needs. The fold 220 and base 210 together form a retrieval hook as a unit that can be mated with a capture system to retrieve the vena cava filter.

In some embodiments of the present invention, with continued reference to fig. 10, the base 210 may include a first linear member 2101; the bent portion 220 may include a second linear member 2201 extending outward in a radial direction. In specific implementation, the angle between the second linear element 2201 and the first linear element 2101 may range from 0 to 45 °, and may be specifically selected according to the situation. It should be noted that, since the first linear element 2101 and the second linear element 2201 are linear members, the recovery body formed by the linear members has a certain folded angle, and the folded angle can make the capture system more easily capture the recovery body, thereby further improving the retrievability of the vena cava filter.

Fig. 11 shows a schematic structural view of another recycling body provided by an embodiment of the present invention, and referring to fig. 11, unlike the recycling body shown in fig. 10, a base 210 of the recycling body may include: a third linear element 2102; the bent portion 220 includes: a fourth linear element 2202 fixedly attached to the third linear element 2102 and disposed parallel or nearly parallel to the third linear element, the distance from the third linear element 2102 being less than a predetermined distance threshold.

In a specific implementation, the preset distance threshold may be set according to actual conditions.

With the above embodiment, when the vena cava filter is caught by the capturing system, since the linear members arranged in parallel or nearly in parallel can be more firmly matched with the capturing system, and the distance between the fourth linear member 2202 and the third linear member 2102 is smaller than the preset distance threshold, the recovery body is not easily separated from the capturing system when the capturing system catches the recovery body, thereby improving the success rate of the recovery operation after the capturing of the vena cava filter and improving the recoverability of the vena cava filter.

To further the understanding of the technical effects of the vena cava secondary filter provided by embodiments of the present invention, the following description is provided in conjunction with specific experimental records.

Simulation experiment 1

Subject of the experiment: testing the pushing force and the recovery force in the filter conveying and recovery process; experimental apparatus: a pushing force tester and a blood vessel model;

test samples: an experimental filter as a control; the vena cava secondary filter provided by the embodiment of the invention is used as an experimental article.

Fig. 12 shows a schematic diagram of the structure of an experimental filter as a control of simulation experiment 1 in an embodiment of the present invention, which includes a plurality of filter rods 1201 and a plurality of balance rods 1202 and has only one filtering effect, with reference to fig. 12.

The testing steps are as follows:

1. connecting the blood vessel model to a water bath circulation system of a pushing force tester, wherein a circulation medium is normal saline and the set temperature is 37 ℃;

2. conveying simulation test: and releasing the vena cava filter into the vena cava blood vessel model through a conveying system according to clinical steps, and testing and recording the maximum pushing force through a pushing force instrument in the process. Both filters were tested 3 times each.

3. And (3) recovery simulation test: and (3) according to the recovery step, recovering the vena cava filter from the vena cava blood vessel model to a recovery sheath through a capture system, and testing and recording the maximum recovery force through a push force instrument in the process. Both filters were tested 3 times each.

TABLE 1 test data record table of pushing force and recovering force in filter conveying and recovering process

Referring to table 1, it can be seen from the above experimental data that the vena cava secondary filter provided by the embodiment of the present invention can reduce the resistance during the delivery and recovery process, compared to the vena cava filter shown in fig. 12.

Simulation experiment 2

Subject of the experiment: carrying out a capture and cutting capability experiment on thrombus;

experimental apparatus: peristaltic pump, vena cava vessel structure model;

experimental materials: fresh pig blood (containing 4% of sodium citrate), normal saline, 100U thrombin and a 10-16 mm silicone tube;

test samples: the experimental filter is used as a reference substance, and the vena cava secondary filter provided by the embodiment of the invention is used as an experimental substance.

The structure of the experimental filter used as the control was the same as that of the experimental filter used in the simulation experiment 1, and the specific structure thereof can be referred to fig. 12.

The testing steps are as follows:

1. connecting the peristaltic pump to the model, then starting the peristaltic pump, adjusting the flow of the circulating medium to 3.5L/min by using normal saline, and simulating the blood flow rate of the vena cava.

2. Preparing thrombus: adding about 2-4 mL of blood into a silicone tube, then adding 0.2mL of thrombin diluted to 0.05-0.1U, rapidly mixing, and standing for 5 minutes to obtain the thrombus.

3. Vena cava secondary filter release: the vena cava secondary filter was released into the vena cava vascular model following the clinical procedure.

4. And (3) thrombus capture test: and releasing the prepared thrombus into a lower limb blood vessel of the model through a silicone tube, respectively testing the two filters for 3 times, and counting the thrombus capture capacity of the two filters.

TABLE 2 Thrombus Capture and cutting Capacity test data record Table

Fig. 13 shows a photograph of a control sample of simulation experiment 2 capturing thrombus, and referring to fig. 13, the experimental filter can filter the thrombus only once and cannot cut it.

Fig. 14 is a photograph showing the capture of thrombus by the experimental article of the simulation experiment 2, and referring to fig. 14, the vena cava secondary filter provided by the embodiment of the present invention as the experimental article can cut thrombus and perform secondary filtration on the thrombus.

Referring to table 2, based on the above experimental data, it can be known that the vena cava secondary filter provided in the embodiment of the present invention realizes the secondary thrombus capture capability, and realizes thrombus cutting, and after the cut fine thrombus enters the lung, pulmonary embolism cannot be further caused, and the large thrombus can be captured secondarily. Therefore, the vena cava can be prevented from being blocked by the large thrombus of the vein of the lower limb to a certain extent.

Although the embodiments of the present invention have been disclosed, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (16)

1. A vena cava secondary filter, comprising: the recovery body is fixedly connected with the filtering body and is suitable for recovering the filtering body;

the filter body comprises a plurality of first filter rods and a plurality of second filter rods;

the first filter rod includes:

the long rod extends outwards from the near end of the filter body, and a plurality of long rods form a radial structure;

the first anchoring piece is arranged at the far end of the long rod;

the second filter rod includes:

a first support portion extending outwardly from a proximal end of the filter body to a maximum diameter of the filter body and extending inwardly to support a vessel wall;

a cutting part, one end of which is fixedly connected with the first supporting part and is reversely curled at the bottom of the filter body to extend towards the direction of the recovery body;

and a second anchor provided at an end of the cutting portion in a direction toward the recovery body.

2. The vena cava secondary filter of claim 1, wherein the cutting portion comprises:

one end of the first cutting part is fixedly connected with the first supporting part, extends towards the bottom of the filter body and is suitable for cutting thrombus;

and one end of the second cutting part is fixedly connected with the first cutting part, extends to the bottom of the filter body, is reversely curled and extends towards the direction of the recovery body, and is suitable for cutting thrombus.

3. The vena cava secondary filter of claim 1, wherein the filter body further comprises: a plurality of balance bars;

the balance bar includes:

a first extension extending outwardly from a proximal end of the filter body;

and the second extension part is fixedly connected with the first extension part and extends along the direction parallel to the axis of the filter body so as to form line contact with the blood vessel wall.

4. A vena cava secondary filter according to claim 3,

at least one of the first filter rod, the second filter rod and the balance rod is arranged symmetrically along the axis of the filter body.

5. The vena cava secondary filter of claim 4, wherein the angle at which the first support portion of the second filter rod extends outwardly from the proximal end of the filter body is greater than the angle at which the elongate rod of the first filter rod extends outwardly from the proximal end of the filter body.

6. The vena cava secondary filter of claim 5, wherein the length of the first extension of the balance bar is less than the length of the first support portion of the second filter bar extending outwardly from the proximal end of the filter body to a point of maximum diameter of the filter body.

7. A vena cava secondary filter according to any of claims 1 to 6,

the extending direction of the first anchoring piece is the same as that of the first filter rod;

the second anchor extends in a direction opposite to the direction in which the first anchor extends.

8. The vena cava secondary filter of claim 7, wherein the first anchor and/or the second anchor comprises:

a base;

a fixed spine extending separately from the base;

the limiting piece is separated and extends out from the base and forms an included angle with the fixed thorn.

9. The vena cava secondary filter of claim 8, wherein the retaining member has a length greater than the fixation spike and wherein an end of the retaining member distal from the base portion comprises an extension extending toward a side of the fixation spike.

10. The vena cava secondary filter of claim 8, wherein an end of the fixation spike distal from the base is nestingly disposed within the interior of the retainer.

11. The vena cava secondary filter of claim 1, wherein the retraction body comprises:

the cone is fixedly connected with the filter body;

and the hook part is arranged on the cone and is suitable for recovering the vena cava secondary filter.

12. The vena cava secondary filter of claim 11, wherein the hook is disposed at the top of the cone and has a central hollow forming a hook-like structure.

13. The vena cava secondary filter of claim 1, wherein the retraction body comprises:

the novel garbage recycling device comprises two recycling pieces which are symmetrically arranged, wherein the whole outline of each recycling piece is of a conical structure, and the top of each conical structure is hollowed to form a hook part.

14. The vena cava secondary filter of claim 1, wherein the retraction body comprises a base portion and a fold portion fixedly connected to the base portion, wherein:

the first end of the base part is fixedly connected with the filter body, and the second end of the base part is fixedly connected with the first end of the bent part;

the second end of the bending part extends towards the direction of the filter body and forms a recovery hook with the base part.

15. The vena cava secondary filter of claim 14, wherein the base comprises a first linear member;

the kink includes: and the second linear piece extends outwards along the radial direction, and the angle between the second linear piece and the first linear piece ranges from 0 degree to 45 degrees.

16. The vena cava secondary filter of claim 14, wherein the base comprises: a third linear element;

the kink includes: and the fourth linear piece is fixedly connected with the third linear piece, is arranged in parallel or nearly in parallel, and has a distance smaller than a preset distance threshold value with the third linear piece.

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