A vena cava filter

Abstract

The present invention relates to the technical field of implantable medical devices, and in particular to an intracavitary implant structure, and more particularly to a vena cava filter. Specifically disclosed are an intracavitary implant structure and a vena cava filter having the structure, comprising a central portion having a central axis and a functional portion having an outer periphery composed of a plurality of rods extending outward from the central portion. By improving the arrangement, structure and shape of the rods constituting the functional portion, the implant has better neutropenia and other effects.

Description

Technical Field

[0001] The present invention relates to the technical field of implantable medical devices, in particular to an intracavitary implant structure, and in particular to a vena cava filter. Background Art

[0002] Implantable medical devices refer to medical devices that can be left in the body for a short or long period of time to support and maintain life, are potentially dangerous to the human body, and must be strictly controlled for their safety and effectiveness. Expandable implantable medical devices such as vascular stents, vena cava filters, occluders, and ventricular volume reduction devices can be compressed to a very small volume and implanted into the human cavity through interventional surgery. After the compressed device is released and expanded at the desired location in the body, it achieves a therapeutic effect, such as expanding, supporting, blocking, reducing the volume of blood vessels or body cavities, or preventing the circulation of blood clots in the blood.

[0003] Whether it is a short-term temporary placement or a long-term or lifelong implantation, strict requirements are required on the body shape of the compression device implanted in the cavity after it is released and expanded in the body. For example, the longitudinal axis of the implant should usually be maintained in the center of the implanted body cavity, that is, the implant has good neutrality, otherwise it may lead to weakening or loss of implant function.

[0004] However, good neutropenia can be difficult to achieve. A typical example is a parachute-shaped vena cava filter, such as the Gunther Tulip manufactured and sold by William Cook. TM Filter and Celect TM Filter, relevant documents such as US5324304A. This type of filter is mainly composed of slender support bodies arranged or woven to form an umbrella-shaped filter part to prevent thrombus in the vein from passing through the filter. At least one end of the slender support body is assembled at the central position of the umbrella-shaped body. This position is usually also provided with a release or recovery part, such as a recovery hook, for cooperating with a sheath to release or recover the umbrella-shaped body. The parachute-shaped vena cava filter lacks effective limit near the recovery hook, and the probability of filter tilting during and during filter implantation is high. Filter tilt is defined as the angle between the longitudinal axis of the filter and the longitudinal axis of the center of the vena cava>15°. Severe filter tilt causes the recovery hook to adhere to the wall of the inferior vena cava or adhere to it, and the umbrella is unevenly unfolded, resulting in serious events such as the inability to recover the filter, reduced thrombus filtering effect, and perforation. Some literature shows that the cause of filter tilt may be related to factors such as aortic pulsation, gastrointestinal motility, the anatomical morphology of the inferior vena cava itself, and the location of filter placement.

[0005] Improved filter structures have been disclosed, such as patent publications US20100049239A1, WO2018120414A1, and CN105193521A, which add a limiting mechanism near the recovery hook, which has the effect of improving the filter tilt and improving the neutralization effect. However, these improved filter structures still have some defects. For example, the limiting mechanism is usually composed of a rod arranged near the filter. When such limiting mechanism rods are arranged longer or in larger numbers, it helps to improve the neutralization effect, but at the same time, it will significantly increase the difficulty of releasing the filter. The resistance of the compressed limiting mechanism is very large when it is released from the sheath. The release operation in the body cavity will be difficult to use a large force due to its fineness, and this type of filter may not be realized when passing through a tortuous delivery cavity, and there are also higher requirements for the delivery system. On the other hand, when such a limiting mechanism is released from the sheath, a significant forward jump phenomenon will occur, and the impact of pumping may cause damage to the cavity, and the final placement position and posture of the filter cannot be effectively controlled.

[0006] However, reducing the number of rods or the length of the rods will provide low support stability, and the neutral effect may not be achieved. For example, the limiting mechanism rod may be deflected to the side when under pressure and lose the limiting effect. It is particularly typical that when the sheath and the cavity are not coaxial, the extension space and the compression force of the inner wall of the cavity when the rods of the limiting mechanism in different directions are released are different, and the limiting mechanism rod close to the inner wall of the cavity is more likely to deflect laterally. In addition, the greater the distance between the limiting mechanism and the bottom of the filter, that is, the greater the height of the filter, the more unavoidable this phenomenon is. Summary of the invention

[0007] The present invention provides an intracavitary implant structure and a vena cava filter having the structure, which at least has the feature of solving or improving one or more of the above-mentioned disadvantages.

[0008] One aspect of the present invention is to provide an intracavitary implant structure, comprising a central portion having a central axis and a functional portion having a periphery formed by a plurality of rods extending outward from the central portion, wherein the periphery of the functional portion is compressible around the central axis.

[0009] The functional part can at least serve as a positioning structure of the implant. The functional part can be compressed to make it elastic. The implant can be anchored in a human lumen, such as a blood vessel, by utilizing the elastic force of the functional part in a compressed state tending to restore to an uncompressed state. In the anchored state, the central axis can tend to be located in the center of the human lumen, or the functional part can conform to the shape of the human lumen.

[0010] Among them, at least one rod is provided with a bending portion protruding toward the outside of the functional portion, and is divided into an upper branch segment and a lower branch segment with different angles with the central axis above and below the bending portion. The rod is also provided with a side branch segment extending outward at or near the bending portion. In a non-compressed state, the farthest end of the side branch segment from the central axis is located between the end of the lower branch segment and the bending portion.

[0011] In one embodiment of the present invention, the side branch segment is coplanar with the central axis, two lower branch segments are led out from below the bent portion, and the two lower branch segments are respectively located on both sides of the coplanar surface.

[0012] In one embodiment of the present invention, the angle between the extension direction of the upper branch segment and the central axis is greater than the angle between the extension direction of the lower branch segment and the central axis.

[0013] In one embodiment of the present invention, the side branch segment comprises an arc-shaped curved segment extending upward, and the deflection angle of the end of the arc-shaped curved segment relative to the starting end thereof is greater than 90 degrees.

[0014] In a preferred embodiment of the present invention, the radius of curvature of the arc-shaped curved section gradually increases toward its end.

[0015] In a preferred embodiment of the present invention, the side branch segment further includes a straight segment, and the straight segment is led out from the bending portion substantially parallel to the lower branch segment, and then transitions to the arc-shaped curved segment.

[0016] In a preferred embodiment of the present invention, there are at least two lower branch sections, which are arranged along the width direction of the rod with the straight section located therebetween.

[0017] In a preferred embodiment of the present invention, a portion of the arc-shaped curved section near its end is substantially parallel to the central axis or nearly parallel to the central axis.

[0018] In one embodiment of the present invention, the side branch segment also includes a tail segment, which is led out from the end of the arc-shaped curved segment, the tail segment points in the direction of the central axis, and the rod width of the tail segment is smaller than the rod width of other parts in the arc-shaped curved segment.

[0019] The tail section may have a spherical structure with a flange and a spherical end or a spherical-like structure.

[0020] In some embodiments of the present invention, the width of the upper branch segment is greater than the width of the lower branch segment and the side branch segment, respectively, and the arc-shaped curved segment of the side branch segment includes a parallel segment substantially parallel to the central axis to form a pressure contact with the inner wall of the body cavity. The radius of curvature of the arc-shaped curved segment gradually increases from its starting end to the end of the pressure contact segment, and a curved tail segment is extended toward the central part after the parallel segment, and the width of the tail segment is less than the width of other segments in the side branch segment. The change in width can reduce the resistance of the rod to be returned to the sheath or released from the sheath, and the operability of the implant during release and recovery is improved. The width processing of the tail segment can effectively prevent the side branch segment from being stuck at the sheath opening when it is returned to the sheath, because when the implant implanted in the blood vessel is recovered, the central axis of the central part is almost impossible to coincide with the central axis of the sheath opening, and at least some side branch segments must be received in the sheath opening in an inclined posture, which leads to the high incidence of the side branch segment being stuck at the sheath opening.

[0021] In an optional embodiment of the present invention, the intracavitary implant structure may also have one or more of the following structural features in any combination:

[0022] Structure 1, the straight section forms an angle with the central axis;

[0023] Structure 2, the arc-shaped curved section has a lowest point along the central axis, and the lowest point is located between the proximal end and the distal end of the arc-shaped curved section;

[0024] Structure three, the deflection angle of the distal end of the arc-shaped curved section relative to its proximal end is not greater than 180 degrees.

[0025] Structure 4: The distal end of the side branch segment is deflected at an angle greater than 180 degrees relative to the proximal end thereof.

[0026] In an optional embodiment of the present invention, the rods constituting the functional part are not fixedly connected to each other.

[0027] Another aspect of the present invention is to provide a vena cava filter having the intracavitary implant structure as described above.

[0028] The bars of the functional part are evenly distributed along the circumference, and are used to prevent the thrombus in the vena cava from passing through the functional part.

[0029] In one embodiment of the present invention, each bar of the functional part leads out two lower branches extending in opposite directions at the bending part, and in the compressed state, adjacent bars are abutted against or crossed with each other through the two adjacent lower branches, so that the functional part forms a mesh structure.

[0030] The two lower branches can improve the peripheral support performance, and the staggered lower branches and side branches can reduce the release resistance of the rod. After the filter is implanted in the blood vessel for a period of time, endothelialization will occur, and the endothelium will crawl over the rod of the implant, making it difficult to recover the filter, increasing the damage to the blood vessel during recovery, and even making it impossible to recover. The two lower branches are not fixedly connected, so that the lower branches have a large degree of freedom, making it easier to extract from the endothelial tissue, reducing damage to the blood vessel. At the same time, the contact between the two lower branches can also improve the support capacity of the rod and the stability of the shape, so that the filter can be more stably maintained in the required shape at the fixed point release position in the blood vessel to prevent the filter from migrating.

[0031] In one embodiment of the present invention, in a non-compressed state, two adjacent lower branch sections between adjacent rods abut against each other away from their ends.

[0032] Another aspect of the present invention is to provide another structure of an intracavitary implant or an intracavitary implant having such a structure, comprising a central portion having a central axis and a functional portion having an outer periphery composed of a plurality of rods extending outward from the central portion, wherein the functional portion is compressible.

[0033] The functional part can at least serve as a positioning structure of the implant. The functional part can be compressed to make it elastic. The implant can be anchored in a human lumen, such as a blood vessel, by utilizing the elastic force of the functional part in a compressed state tending to restore to an uncompressed state. In the anchored state, the central axis can tend to be located in the center of the human lumen, or the functional part can conform to the shape of the human lumen.

[0034] The present invention provides an intracavitary implant structure, in a non-compressed state, the functional portion at least comprises a first periphery, a second periphery and a third periphery formed by flanges or free ends of a plurality of rods arranged around the central axis, the first periphery, the second periphery and the third periphery are arranged outward from the central portion in sequence and are not coplanar with each other, and the first periphery and the second periphery are closer to the central portion along the central axis than the third periphery;

[0035] The flange or free end of the rod can be pressed to move toward the central axis, and the second periphery and the third periphery can be pressed to position and maintain the implant in the first posture in the cavity where it is implanted;

[0036] When any one or more flanges or free ends constituting the first periphery are compressed, the implant can be positioned and maintained close to the first posture in the cavity where it is implanted.

[0037] Obviously, the flange is directed toward the outside of the functional part to provide a possible support site when the implant is in the anchored state.

[0038] The second periphery and the third periphery constitute two layers of support sites distributed along the long axis of the cavity of the functional part, which can contact the inner wall of the cavity where the implant is implanted. Compared with the non-compressed state, the second periphery and the third periphery are subjected to the pressure of the cavity inner wall, which can resist the inclination of the central part or the central axis toward the cavity inner wall, maintain a certain distance between the central part and the cavity inner wall, and form the desired first posture. When the flange or free end of any one or more rods of the second periphery loses its supporting function due to various factors, for example, the flange or free end shifts to its side, and its supporting function is lost or weakened, the flange or free end of the rod of the first periphery near the support site can be against the cavity inner wall to form a second posture, resist the inclination of the central part or the central axis toward the side of the cavity inner wall where the shifted support site is located, and prevent the central part from sticking to the wall, that is, the implant can keep the second posture close to the first posture as much as possible.

[0039] In one embodiment, the number of flanges or free ends constituting the first outer periphery is not less than the number of flanges or free ends constituting the second outer periphery, and they are at least one-to-one corresponding. The flanges or free ends constituting the first outer periphery and the corresponding flanges or free ends constituting the second outer periphery may be located substantially in the same radial direction. For example, a preferred embodiment of the one-to-one correspondence may be that one flange or free end constituting the first outer periphery and another flange or free end constituting the second outer periphery are located substantially in the same radial direction.

[0040] In one embodiment, the first periphery is located between the second periphery and the third periphery along the direction of the central axis, or the second periphery is located between the first periphery and the third periphery along the direction of the central axis.

[0041] In one embodiment, the first outer periphery is formed by a flange of the rod.

[0042] Optionally, any periphery may be optionally constituted by a flange or a free end. For example, the third periphery and the second periphery are both constituted by the free ends, or the third periphery is constituted by the free ends and the second periphery is constituted by the flange.

[0043] The rods constituting the outer periphery may include at least a first array of rods and a second array of rods.

[0044] In one embodiment, the third periphery is formed by arranging the free ends of the first array of rods, and the second periphery is formed by arranging the free ends or flanges of the second array of rods.

[0045] In one embodiment, the third periphery is formed by arranging the free ends of the first array rods, the first array rods are further provided with branches, and the second periphery is formed by arranging the free ends or flanges of the branches of the first array rods.

[0046] As a further improvement, the first array rods are further provided with flanges, and the first periphery is formed by the flanges of the first array rods. For example, the first array rods all have a bending portion, and the front section and the rear section of the first array rods at the respective bending portions form an angle at the bending portion, and the bending portion of the first array rods forms the flanges.

[0047] In one embodiment, the rod where the free end or flange constituting the second outer periphery is located has a curved section extending in a direction away from the third outer periphery, and the end or protruding end of the curved section constitutes the free end or flange of the second outer periphery.

[0048] Preferably, the second outer periphery is radially closer to the first outer periphery.

[0049] Optionally, the first periphery, the second periphery and the third periphery are all located on the same side of the central portion.

[0050] Preferably, the flange or the free end has a smooth curved surface, and can contact the inner wall of the cavity where the implant is implanted through the smooth curved surface.

[0051] Preferably, the number of flanges or free ends constituting the third outer periphery is greater than the number of flanges or free ends constituting the second outer periphery.

[0052] As a further improvement, the number of flanges or free ends constituting the third outer periphery is twice the number of flanges or free ends constituting the second outer periphery, and the flanges or free ends constituting the third outer periphery are distributed in pairs, and each pair of flanges or free ends constituting the third outer periphery are staggered with the flanges or free ends constituting the second outer periphery along the circumferential direction of the central axis.

[0053] Preferably, each bar of the functional part is made by integrally cutting a tube and then shaping it.

[0054] Another aspect of the present invention is to provide a vena cava filter having the intracavitary implant structure as described above, wherein the bars of the functional part are evenly distributed along the circumference to prevent thrombus in the vena cava from passing through the functional part.

[0055] Another aspect of the present invention provides a retrievable intracavitary implant structure or a retrievable intracavitary implant having such a structure, comprising a central portion having a central axis and a functional portion consisting of a plurality of rods extending outward from the central portion and arranged around the central axis; the implant can be positioned and maintained in the cavity where it is implanted by compression of the functional portion by the inner wall of the cavity.

[0056] The functional part can at least serve as a positioning structure of the implant. The functional part can be compressed to make it elastic. The implant can be anchored in a human lumen, such as a blood vessel, by utilizing the elastic force of the functional part in a compressed state tending to restore to an uncompressed state. In the anchored state, the central axis can tend to be located in the center of the human lumen, or the functional part can conform to the shape of the human lumen.

[0057] Wherein, at least one rod comprises an arc-shaped curved section, and the radius of curvature of the arc-shaped curved section gradually increases from its proximal end close to the central portion to its distal end.

[0058] In one embodiment of the present invention, the radius of curvature gradually increases, and the arc-shaped curved section tends to be straighter toward its distal end, and the resistance when it is returned to the sheath tube is smaller.

[0059] In one embodiment of the present invention, the arc-shaped curved section is substantially parallel to the central axis or nearly parallel to the central axis near its distal end.

[0060] In one embodiment of the present invention, the rod further extends to have a tail section at the distal end of the arc-shaped curved section.

[0061] In one embodiment of the present invention, the tail section is parallel to the central axis or bends toward the central axis.

[0062] In one embodiment of the present invention, the end of the rod is a spherical body or a spherical body similar to a spherical body with a flange spherical surface structure.

[0063] In one embodiment of the present invention, the rod as a whole has a tendency of decreasing in width toward its end.

[0064] In one embodiment of the present invention, the diameter of the spherical body or spherical body at the end of the rod is greater than the rod width of the adjacent section. For example, the rod width of the tail section is smaller than the rod width of the arc-shaped curved section.

[0065] In one embodiment of the present invention, the rod is further provided with a straight section on the proximal side of the arcuate curved section, the rod extends from the straight section out of the arcuate curved section, and the straight section forms an angle with the central axis.

[0066] In one embodiment of the present invention, the arc-shaped curved section has a lowest point along the direction of the central axis, and the lowest point is located between the proximal end and the distal end of the arc-shaped curved section.

[0067] In one embodiment of the present invention, the distal end of the arc-shaped curved segment is deflected at an angle greater than 90 degrees relative to the proximal end thereof.

[0068] Another aspect of the present invention is to provide a vena cava filter having the aforementioned retrievable intracavitary implant structure.

[0069] In summary, the intracavitary implant structure and the vena cava filter having the structure as the preferred or better embodiment of the present invention can have good neutropenia, transportability, safety and ease of operation.

[0070] In the embodiments of the present invention, the intracaval implant or vena cava filter can be used as a retrievable device, which can have the effects of a longer implantation period, a higher success rate of retrieval, and less damage to the vena cava. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 and Figure 2 Schematic diagram of a single rod of two implant structure embodiments of the present invention;

[0072] Figure 3-9 Schematic diagram of two symmetrical rods of different implant structure embodiments of the present invention;

[0073] Figure 10-12 The three implant structure embodiments of the present invention are views along the central axis direction;

[0074] Fig.13 and Fig.14 They are schematic diagrams of different directions of a preferred embodiment of the vena cava filter of the present invention;

[0075] Fig.15 for Fig.13 A partial enlarged schematic diagram;

[0076] Fig.16 and Fig.17 They are two different effect diagrams of a preferred embodiment of a vena cava filter of the present invention after being released from the implant cavity;

[0077] Fig.18 and Fig.19 The finite element analysis diagrams of two embodiments of vena cava filters simulating the stress after implantation into the cavity are shown respectively.

[0078] In each of the drawings, the reference numerals are described as follows:

[0079] 1. Central portion; 2. First array rod; 21. Upper branch segment; 211. Bending portion; 22, 221, 222. Lower branch segment; 23. Side branch segment; 31. First periphery; 32. Second periphery; 33. Third periphery; 4. Second array rod; 5. Inner wall of the cavity. DETAILED DESCRIPTION

[0080] A type of intracavitary implant structure in the prior art includes a central portion with a central axis and a functional portion with a periphery formed by a plurality of rods extending outward from the central portion, wherein the periphery of the functional portion surrounds the central axis and can be compressed by the inner wall of the cavity toward the central axis, so that the implant is positioned and maintained in the cavity where it is implanted. A typical structure of this type of implant can be found in the filter structure disclosed in WO2017186025A1 of the inventor of the present application, and the entire text is introduced into this patent. The aforementioned implant in a stronger compression state has a small shape and volume and can be placed in a sheath tube, and is transported in a human cavity through the sheath tube. At the required placement position, the implant is released from the sheath tube by the operator, and the aforementioned implant in a stronger compression state expands and tends to a non-compressed state, and its functional portion rod expands away from the central axis and presses against the inner wall of the implanted cavity, and multiple rods form a circumferential support for the implant, and at this time, the functional portion expands relative to its stronger compression state and is maintained to a weaker compression state so that the implant is positioned and maintained in the cavity where it is implanted.

[0081] However, the above description is non-limiting. For example, the intracavitary implants disclosed in CN1399530A, CN1842354A, CN105208947A, etc. also have similar structures.

[0082] The embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0083] Intracavitary implant structure

[0084] One object of the present invention is to provide an improved intracavitary implant structure, in which, in a non-compressed state, the functional portion at least comprises a first periphery 31, a second periphery 32 and a third periphery 33 formed by flanges or free ends of a plurality of rods arranged around a central axis, the first periphery 31, the second periphery 32 and the third periphery 33 are arranged outward from a central portion 1 in sequence and are not coplanar with each other, and the first periphery 31 and the second periphery 32 are closer to the central portion 1 along the central axis than the third periphery 33;

[0085] The flange or free end of the rod can be pressed to move toward the central axis, and the second periphery 32 and the third periphery 33 can be pressed to position and maintain the implant in the first posture in the cavity where it is implanted;

[0086] When any one or more flanges or free ends constituting the first periphery 31 are compressed, the implant can be positioned and maintained in the cavity where it is implanted so as to approach the first posture.

[0087] The flange faces the outer side of the functional part.

[0088] The flange of the embodiment of the present invention may be the bent portion 211 of the rod, facing the outer side of the functional portion, as shown in FIG. Figure 1-9 , or the farthest end of the arc-shaped curved segment from the central axis, refer to Fig.15 The curvature radius of the segment is D2. However, non-limitingly, those skilled in the art may also choose other forms of flanges, which can serve as support sites and contact the inner wall of the implanted cavity to limit and support the implant. The flange is preferably the bent portion 211 of the rod, Figure 1-9 or Fig.13 The bending portion 211 has a non-arc-shaped bend, so that the rod forms a relatively fixed angle above and below the bending portion 211, which can reduce the compression force transmitted to the root of the rod when the end of the rod is compressed by the inner wall of the cavity, because the angle of the bending portion 211 can be reduced due to the pressure on the end of the rod, which plays a role in buffering or reducing the force transmitted to the root of the rod. At the same time, the lower branch section of the rod led out from the bottom of the bending portion 211 provides the end of the rod, and the lower branch section has a greater elastic restoring force due to the smaller angle of the bending portion 211, thereby providing the implant with stronger support and positioning in the implant cavity.

[0089] Continue to refer Fig.15 and Fig.16 The segment with a radius of curvature D2 can be a pressure contact segment that is basically parallel to the central axis or tends to be parallel to the central axis, and can be pressed against the inner wall of the implanted cavity to form a support or support for the positioning of the implant. The radius of curvature of the entire arc-shaped curved segment gradually increases from its starting end to the end of the pressure contact segment. The pressure contact segment, which tends to be parallel to the central axis and can be a basically straight line, has an angle of no more than 15 degrees with the central axis. This arrangement is beneficial for the pressure contact segment to be collected into the recovery sheath when the implant is recovered, thereby reducing the recovery resistance to the deformation of the implant caused by the inner wall of the body cavity and the recovery sheath opening, and is also beneficial for the pressure contact segment to provide a larger area of ​​contact with the inner wall of the body cavity when implanted, thereby improving the stability of the anchoring effect.

[0090] See also Figure 10-12 , three implant structure embodiments of the present invention are shown, all of which have a first periphery 31, a second periphery 32 and a third periphery 33 formed by the flange or free end of the rod, and their radii are a, b, c respectively. Fig.12 The shape of each rod constituting the functional part of the implant can be Figure 7-9 Any of Fig.10 and Fig.11 The shape of each rod constituting the functional part of the implant can be Figure 1-6 Any one of . Fig.10 and Fig.11 The main difference in the functional part of the implant lies in the number and shape of the lower branch segments of the rod.

[0091] The second periphery 32 and the third periphery 33 constitute two layers of support sites distributed along the long axis of the cavity of the functional part, which can contact the inner wall of the cavity where the implant is implanted. Compared with the non-compressed state, the second periphery 32 and the third periphery 33 are subjected to the pressure of the cavity inner wall, which can resist the inclination of the central part 1 or the central axis toward the cavity inner wall, maintain a certain distance between the central part 1 and the cavity inner wall, and form the desired first posture. When the flange or free end of any one or more rods of the second periphery 32 loses its supporting function due to various factors, for example, the flange or free end shifts to its side, and its supporting function is lost or weakened, the flange or free end of the rod of the first periphery 31 near the support site can be against the cavity inner wall to form a second posture, resist the inclination of the central part 1 or the central axis toward the side of the cavity inner wall where the offset support site is located, and prevent the central part 1 from sticking to the cavity wall, that is, the implant can keep the second posture close to the first posture as much as possible.

[0092] However, the above description is non-restrictive, and the implant can directly present the second posture instead of the first posture after being released from the cavity through the sheath, and the first posture can be the ideal implantation state desired by the operator. For example, the implant is released when the sheath and the cavity have a poor overlap along the long axis.

[0093] As a non-limiting example, another possible situation is that the peristalsis, contraction, etc. of the cavity causes the position or shape of the implanted implant to change from the initial first posture to the second posture.

[0094] Fig.13 and 14 The preferred embodiment of an implant of the present invention is shown in FIG. 1 , and the top view along the central axis of the central part 1 is similar to FIG. Fig.11 , with three peripheries, Fig.16 and 17 Showing two postures of the implanted cavity. Fig.16 The implant posture shown is generally desirable. Fig.17 At least one supporting point of the second periphery 32 fails due to lateral deviation, and the bent portion 211 of the rod constituting the first periphery 31 nearby acts as a supporting point. The implant posture avoids more excessive tilting of the central part 1 or the central axis, and maintains an appropriate distance between the central part 1 and the cavity wall.

[0095] As a preferred embodiment, the number of flanges or free ends constituting the first outer periphery 31 is not less than the number of flanges or free ends constituting the second outer periphery 32 , and they are at least one-to-one corresponding. Fig.10 and Fig.11A radially corresponding method along the periphery is shown, wherein the number of flanges or free ends constituting the first periphery 31 is equal to the number of flanges or free ends constituting the second periphery 32, and the corresponding flanges or free ends of the two peripheries are basically located in the same radial direction, which enables the first periphery 31 to have a better effect of supplementing the support sites, and the supplementary support for the failure sites of the second periphery 32 is more precise, so that the inclination angle of the filter can be controlled to be smaller. Fig.12 Another non-radial corresponding manner is shown, which is that the flanges or free ends of any two adjacent second peripheries 32 correspond to a flange or free end of the first periphery 31. Figure 10-12 The number of flanges or free ends of the first outer periphery 31 is equal to the number of flanges or free ends of the second outer periphery 32.

[0096] As a preferred embodiment, the first periphery 31 is located between the second periphery 32 and the third periphery 33 along the central axis direction. Figure 1 and Figure 2 In other optional embodiments, the second periphery 32 is located between the first periphery 31 and the third periphery 33 along the central axis, for example Figure 5 .

[0097] The third outer periphery 33, the second outer periphery 32 and the first outer periphery 31 can all be formed by free ends of rods, for example, by the free ends of the first array rods 2, the second array rods 4 and the third array rods in sequence.

[0098] In a preferred embodiment, the first periphery 31 is formed by the flange of the rod, the third periphery 33 and the second periphery 32 are both formed by the free ends, or the third periphery 33 is formed by the free ends and the second periphery 32 is formed by the flange. For example, the third periphery 33 is formed by the free ends of the first array rods 2, and the second periphery 32 is formed by the free ends or flanges of the second array rods 4. Fig.12 , the shape of each rod can be Figure 7-9 For example, the third periphery 33 is composed of the free ends of the first array rod 2, the first array rod 2 is also provided with branches, the second periphery 32 is composed of the free ends or flanges of the first array rod 2 branches, reference Fig.10 Or 11, the shape of the first array rod 2 and its branches can be Figure 1-9 Any one of .

[0099] The first array rods 2 may also be provided with flanges, and the first periphery 31 is formed by the flanges of the first array rods 2. For example, the first array rods 2 all have a bending portion 211, and the first array rods 2 form an angle at the bending portion 211 at the front section and the rear section of each bending portion 211, and the bending portion 211 of the first array rods 2 forms a flange. Figure 1-6 .

[0100] The rod where the free end or flange constituting the second outer periphery 32 is located has a curved section extending in a direction away from the third outer periphery 33 , and the end or protruding end of the curved section constitutes the free end or flange of the second outer periphery 32 . Figure 1-4 and Figure 6 The first array rod 2 has branches, and a lower branch section 22 and a side branch section 23 extend from an upper branch section 21, wherein the side branch section 23 has a curved section. According to the shape of the curved section, the second periphery 32 can be formed by the end of the curved section as a free end, or by the outermost protruding end of the curved section as a flange.

[0101] In a preferred embodiment, the second outer periphery 32 is radially close to the first outer periphery 31. That is, the radial distance between the first outer periphery 31 and the second outer periphery 32 may be smaller than the radial distance between the second outer periphery 32 and the third outer periphery 33.

[0102] Optionally, the first periphery 31 and the second periphery 32 are located on both sides of the central portion 1 and the third periphery 33 is located on one side. However, preferably, the first periphery 31, the second periphery 32 and the third periphery 33 are all located on the same side of the central portion 1.

[0103] In a preferred embodiment, the flange or the free end has a smooth curved surface, and can contact the inner wall of the cavity where the implant is implanted through the smooth curved surface.

[0104] In a preferred embodiment, the number of flanges or free ends constituting the third periphery 33 is greater than the number of flanges or free ends constituting the second periphery 32. For example, Fig.11 In the implant shown in the figure, the first array rod 2 is divided into two lower branches 221 and 222 from the bent portion 211. The adjacent lower branches of two adjacent first array rods 2 can be in contact with each other but are not fixedly connected. Fig.12 , 16 or 19. In this case, the number of flanges or free ends constituting the third outer periphery 33 is twice the number of flanges or free ends constituting the second outer periphery 32, and the flanges or free ends constituting the third outer periphery 33 are distributed in pairs, and each pair of flanges or free ends constituting the third outer periphery 33 and the flanges or free ends constituting the second outer periphery 32 are staggered along the circumferential direction of the central axis, see Fig.14 .

[0105] The bars of the functional part of the implant of the present invention are preferably made by cutting a pipe integrally and then shaping it. The pipe can be made of shape memory materials such as stainless steel and nickel-titanium alloy, and the designed shape in a non-compressed state is obtained by heat shaping.

[0106] Rods that constitute the functional part

[0107] In some implant embodiments of the present invention, among the multiple rods constituting the functional portion, at least one rod is provided with a bending portion 211 protruding toward the outside of the functional portion, and is divided into an upper branch segment 21 and a lower branch segment 22 with different angles to the central axis above and below the bending portion 211. The rod is also provided with a side branch segment 23 extending outward at the bending portion 211 or near the bending portion 211. In the non-compressed state, the farthest end of the side branch segment 23 from the central axis is located between the end of the lower branch segment 22 and the bending portion 211.

[0108] by Figure 1 and Figure 2 As an example, the two figures show two rods constituting the functional part, wherein the distance between the farthest end of the side branch section 23 and the central axis is b, the distance between the bent portion 211 and the central axis is c, and the distance between the end of the lower branch section 22 and the central axis is a. Obviously, in the non-compressed state, a>b>c. In this embodiment, the side branch section 23 includes an arc-shaped curved section extending upward. The flange formed at the end or the outermost end of the arc-shaped curved section can abut against the inner wall of the implanted cavity in the cavity, thereby playing a supporting role.

[0109] The rod where the bent portion 211 is located is implanted in the cavity, and the farthest end of the side branch segment 23 and the end of the lower branch segment 22 form two supporting sites of the functional portion distributed along the long axis of the cavity to prevent the central portion 1 from tilting toward the side of the cavity wall where the rod is located, and keep a certain distance between the central portion 1 and the cavity wall, see Fig.12 Example.

[0110] When the side branch segment 23 is affected by various factors and is in the side of its non-compressed state, its function as a support site may be lost, and the bent portion 211 of the rod can abut against the inner wall of the cavity, thereby resisting the inclination of the central portion 1 toward the inner wall of the cavity where the rod is located. In addition, at this time, the bent portion 211 and the lower branch segment 22 can abut against the inner wall of the cavity as a whole, the support area of ​​the rod is increased, and the support of the functional part is more stable, but the unit pressure on the inner wall of the cavity is weak, which can avoid crushing or puncturing the inner wall of the blood vessel, see Fig.17 Example.

[0111] The side branch section 23 can be arranged to be led out from the bent portion 211 of the rod, see Figure 1 and Figure 5 , Figure 1 The side branch section 23 is an arc-shaped curved section extending upward. Figure 5 The side branch section 23 shown is a straight section extending downward.

[0112] Alternatively, the branch section 23 is arranged to be led out from the vicinity of the bent portion 211 of the rod.

[0113] In one embodiment, the side branch section 23 is led out from the upper branch section 21, see Figure 2 and Figure 4 , Figure 2 The side branch section 23 shown may be an arc-shaped curved section extending upward. Figure 4 The side branch section 23 shown is an arc-shaped curved section extending downward.

[0114] In another embodiment, the side branch section 23 can be led out from the lower branch section 22, see Figure 3 and Figure 6 .

[0115] Those skilled in the art may select different styles of the side branch segment 23 as needed, which is not limited to the embodiment of the present invention.

[0116] Figure 6 The structure and shape of the rod shown is a preferred embodiment, the rod has an upper branch section 21 extending from the central portion 1, and a lower branch section 22 extending from the bent portion 211. A side branch section 23 is extended from the lower branch section 22 and includes an arc-shaped curved section. The deflection angle of the end of the side branch section 23 relative to its starting end is greater than 180 degrees, and the end thereof points to the direction of the central axis.

[0117] In a further preferred embodiment, the radius of curvature of the arc-shaped curved section gradually increases toward its end. Fig.13 and Fig.15 , Fig.15 The arc-shaped curved section in the embodiment is composed of three sections, and the curvature radius diameters are D1, D2, and D3 in sequence, and increase in sequence, so that the side branch section 23 can fit the blood vessel wall as closely as possible. On the one hand, the side branch section 23 is drawn out from the vicinity of the bending portion 211, and can have a shorter length than that drawn out from the central portion 1, so that its anti-deflection ability is stronger. On the other hand, the gradual increase in the curvature radius can make the side branch section 23 contact the blood vessel wall in line contact rather than point contact.

[0118] The flange formed at the end or the outermost end of the arc-shaped curved section can abut against the inner wall of the implanted cavity in the cavity to play a supporting role. The rod where the bent portion 211 is located is implanted in the cavity, and the farthest end of the side branch segment 23 and the end of the lower branch segment 22 form two supporting sites of the functional part distributed along the long axis of the cavity to prevent the functional part from tilting toward the side of the cavity wall where the rod is located, and keep a certain distance between the central part 1 and the cavity wall, see Fig.16 Embodiment. When the side branch segment 23 is affected by various factors and is in the side of its non-compressed state, its function as a support site may be lost, and the bent portion 211 of the rod can abut against the inner wall of the cavity, thereby resisting the inclination of the functional part toward the inner wall of the cavity where the rod is located. Moreover, at this time, the bent portion 211 and the lower branch segment 22 can abut against the inner wall of the cavity as a whole, the support area of ​​the rod is increased, and the support for the functional part is more stable, but the unit pressure on the inner wall of the cavity is weak, which can avoid crushing or puncturing the inner wall of the blood vessel, see Fig.17 Example.

[0119] For further improvements, see Fig.13 and Fig.15 The side branch section 23 also includes a straight section L, which is substantially parallel to the lower branch section 22 and is led out from the bending portion 211, and then transitions to an arc-shaped curved section. The lower branch section 22 can be one, two or more, and those skilled in the art can set it as needed. When there are at least two lower branch sections 22, in a preferred embodiment, the side branch section 23 is located between the two lower branch sections 221 and 222, and the straight section of the side branch section 23 and the lower branch section are arranged along the rod width direction.

[0120] Based on the above description, the branch segment 23 can be selected to be coplanar or non-coplanar with the central axis. The non-coplanar branch segment 23 may be more difficult to release and recover.

[0121] Fig.10 The side branch section 23 is coplanar with the central axis, and a lower branch section 22 is led out from the bent portion 211 of the rod where the side branch section 23 is located. Fig.11 The side branch section 23 is coplanar with the central axis, and the bending portion 211 of the rod where the side branch section 23 is located leads to two lower branch sections 221 and 222, and the two lower branch sections 221 and 222 are respectively located on both sides of the coplanar surface.

[0122] Fig.10 and Fig.11 The functional part of the implant is composed of the ends of the lower branches of the six first array rods 2 arranged at equal intervals around the central axis to form a third periphery 33, the farthest ends of the side branches 23 of the six first array rods 2 arranged at equal intervals around the central axis to form a second periphery 32, and the bent portions 211 of the six first array rods 2 arranged at equal intervals around the central axis to form a first periphery 31. Fig.12 The functional part of the implant is composed of six first array rods 2 and six second array rods 4 alternating along the circumferential direction.

[0123] In the non-compressed state, the diameter of the third outer periphery 33 is preferably 1.5-4 times the diameter of the second outer periphery 32 , and the second outer periphery 32 is radially close to the first outer periphery 31 .

[0124] The upper branch section 21 and the lower branch section 22 may have a bend or a bend. Fig.11 , 13 , 14, the lower branch segments 221, 222 both have S-shaped curved segments.

[0125] in, Fig.10 The implant has 6 lower branch ends, and Fig.11 The implant can have 6 or 12 lower branch ends. Figure 8 The two adjacent rods of the implant body are abutted or crossed by two adjacent lower branches, so that the functional part forms a mesh structure, but the 12 ends are still kept as free ends, see Fig.13and Fig.14 However, another option is Figure 8 Every two adjacent rods of the implant are joined and fixed to one end through two adjacent lower branch segments, so that the implant can have 6 ends.

[0126] Based on the above description, the preferred embodiment of the present invention is as follows: Figure 1 and Figure 2 , the angle α between the extension direction of the upper branch segment 21 and the central axis is greater than the angle β between the extension direction of the lower branch segment and the central axis. Under the condition that the maximum periphery of the functional part is determined, this structure can have a relatively small height (i.e., the length along the central axis), which is very advantageous in most cases.

[0127] In the present invention, the width of the rod constituting the functional part decreases from the central part 1 toward the outside as a whole.

[0128] For example, the width of the upper branch segment 21 is greater than that of the lower branch segment 22 (or 221 , 222 ) and the side branch segment 23 .

[0129] In a further preferred embodiment, the width of the side branch section 23 decreases from its starting end to its end. For example, the side branch section 23 is divided into two sections with different widths from the bottom of the arc-shaped curved section extending upward. The end of the narrower rear half section can be provided with a spherical round head to avoid puncturing the inner wall of the cavity.

[0130] In the present invention, the length of the upper branch section 21 is preferably much smaller than the length of the lower branch section 22 (or 221 , 222 ), and the length ratio may be in the range of 0.2-0.05.

[0131] In the present invention, the end of the branch segment 23 is preferably located at or near the central portion 1 along the central axis.

[0132] Vena cava filter

[0133] Another aspect of the present invention is to provide a vena cava filter having any of the above-mentioned intracavitary implant structures, wherein the bars of the functional part are evenly distributed along the circumference to prevent thrombus in the vena cava from passing through the functional part.

[0134] See also Figure 10-12 , showing three types of vena cava filters.

[0135] Fig.13 , 14 In a preferred vena cava filter provided by the present invention, each bar of the functional part leads out two lower branches 221 and 222 extending in opposite directions at the bending part 211, and in the compressed state, adjacent bars are abutted or crossed with each other through two adjacent lower branches, so that the functional part forms a mesh structure, see Fig.16 , 17and 19.

[0136] Optionally, in the non-compressed state, two adjacent lower branches between adjacent rods abut against each other at a point away from their ends, and the two lower branches are parallel and close to each other from the abutment point to the end, see Fig.13 , 14 .

[0137] In the preferred embodiment of the vena cava filter of the present invention, the side branch section 23 is led out from the bending portion 211, and is first led out as a straight section substantially parallel to the lower branch section, and then transitions to an arc-shaped curved section with a gradually increasing radius of curvature, and the deflection angle of the end of the arc-shaped curved section relative to its starting end can be greater than or less than 180 degrees, and its end points to the direction of the central axis. The side branch section 23 is located between the two lower branch sections 221 and 222, and the straight section of the side branch section 23 and the lower branch section 22 are arranged along the rod width direction.

[0138] Under the same conditions, compared with the comparative vena cava filter without a bending portion and the lower branch directly leading to the side branch 23 as an arc-shaped curved section, the preferred vena cava filter embodiment of the present invention has better structural mechanics, overall reduced stress, and more uniform stress distribution, see Fig.18 and Fig.19 , Fig.19 The stress at the root (i.e., the starting end) of the lateral branch segment 23 of the preferred vena cava filter embodiment of the present invention is significantly reduced, and there is no stress concentration area at the root, compared with Fig.18 The comparative example shown can significantly reduce the risk of the side branch segment 23 breaking at the root, and at the same time, the lower stress is conducive to the compression and recovery of the side branch segment 23, avoiding forward jumping or reducing the recovery resistance, and the operability and safety are greatly improved.

[0139] Based on the embodiments and related descriptions of the present invention, at least one vena cava filter as described below can be provided.

[0140] 1. A vena cava filter, comprising a central portion having a central axis and a functional portion having an outer periphery formed by a rod extending outward from the central portion, wherein the functional portion is compressible, and the filter can be positioned and maintained in the cavity where it is implanted by compression of the functional portion by the inner wall of the cavity;

[0141] A plurality of the rods are arranged around the central portion to form a first array, the first array rods are provided with a bending portion protruding toward the outside of the functional portion, and are divided into an upper branch section and a lower branch section above and below the bending portion with different angles to the central axis, and the first array rods are also provided with a side branch section protruding outward at the bending portion;

[0142] The side branch section includes a straight section and an arc-shaped curved section, the straight section of the side branch section is substantially parallel to the lower branch section and is led downward from the bending portion, and then transitions to the arc-shaped curved section extending upward;

[0143] The lower branch segments are two and extend in opposite directions, and the side branch segment is located between the two lower branch segments;

[0144] The width of the upper branch segment is greater than the width of the lower branch segment and the side branch segment, respectively; the arc-shaped curved segment of the side branch segment includes a pressure contact segment substantially parallel to the central axis or inclined to be parallel to the central axis; the radius of curvature of the arc-shaped curved segment gradually increases from its starting end to the end of the pressure contact segment; a curved tail segment is extended toward the central portion after the pressure contact segment; and the width of the tail segment is less than the width of other segments in the side branch segment;

[0145] In the non-compressed state, the pressure contact segment constitutes the farthest end of the side branch segment from the central axis, and is located between the end of the lower branch segment and the bent portion;

[0146] In the compressed state, adjacent lower branch sections of two adjacent first array rods are in contact but not fixedly connected.

[0147] 2. For the above vena cava filter, in a non-compressed state, the adjacent lower branch segments of two adjacent first array rods have mutually abutting and contacting close segments, or the adjacent lower branch segments of two adjacent first array rods cross and overlap.

[0148] 3. In the above-mentioned vena cava filter, the side branch segment is provided with a spherical body or a nearly spherical body at the end of the tail segment, the diameter of which is larger than the width of the tail segment.

[0149] 4. In the above-mentioned vena cava filter, the bending portion includes a lead-out section, the width of the lead-out section gradually increases along the outward extension direction of the rod after bending, and then the side branch section and the lower branch section are separated.

[0150] 5. In the above-mentioned vena cava filter, the deflection angle of the end of the side branch segment relative to its starting end is greater than 180 degrees.

[0151] 6. In the above-mentioned vena cava filter, the first array rods are made by integrally cutting a tube and then shaping it.

[0152] 7. In the above-mentioned vena cava filter, the side branch segment is coplanar with the central axis, and the two lower branch segments are respectively located on both sides of the coplanar surface.

[0153] 8. In the above-mentioned vena cava filter, the angle between the extension direction of the upper branch segment and the central axis is greater than the angle between the extension direction of the lower branch segment and the central axis.

[0154] 9. In the above-mentioned vena cava filter, the pressure contact segment that tends to be parallel to the central axis means that the angle between the pressure contact segment, which is basically a straight line, and the central axis is not greater than 15 degrees. This arrangement is not only conducive to the pressure contact segment being put into the recovery sheath when the filter is recovered as an implant, reducing the recovery resistance to the deformation of the implant caused by the inner wall of the vein and the opening of the recovery sheath, but also conducive to the pressure contact segment providing a larger area of ​​contact with the inner wall of the vein when implanted, thereby improving the stability of anchoring.

[0155] 10. In the above-mentioned vena cava filter, the arc-shaped curved section has a lowest point along the direction of the central axis, and the lowest point is located between the two ends of the arc-shaped curved section.

[0156] The present invention has been introduced in detail above. The embodiments of the present invention are described by using specific examples. The description of the above embodiments is only used to help understand the present invention. It should be pointed out that for those skilled in the art, several improvements can be made to the present invention without departing from the principles of the present invention. These improvements also fall within the scope of protection of the claims of the present invention.

Claims

1. A vena cava filter, characterized in that: The filter comprises a central part with a central axis and a functional part with an outer circumference formed by a rod extending outward from the central part, wherein the functional part is compressible, and the filter can be positioned and maintained in the cavity where it is implanted by the compression of the functional part by the inner wall of the cavity; A plurality of the rods are arranged around the central portion to form a first array, the first array rods are provided with a bending portion protruding toward the outside of the functional portion, and are divided into an upper branch segment and a lower branch segment above and below the bending portion with different angles to the central axis, the bending portion has a non-arc bend, and the first array rods are further provided with a side branch segment protruding outward at the bending portion; The side branch section includes a straight section and an arc-shaped curved section, the straight section of the side branch section is substantially parallel to the lower branch section and is led downward from the bending portion, and then transitions to the arc-shaped curved section extending upward; The lower branch segments are two and extend in opposite directions, and the side branch segment is located between the two lower branch segments; The width of the upper branch segment is greater than the width of the lower branch segment and the side branch segment, respectively; the arc-shaped curved segment of the side branch segment includes a pressure contact segment substantially parallel to the central axis or inclined to be parallel to the central axis; the radius of curvature of the arc-shaped curved segment gradually increases from its starting end to the end of the pressure contact segment; a curved tail segment is extended toward the central portion after the pressure contact segment; and the width of the tail segment is less than the width of other segments in the side branch segment; In the non-compressed state, the pressure contact segment constitutes the farthest end of the side branch segment from the central axis, and is located between the end of the lower branch segment and the bent portion; In the compressed state, adjacent lower branch sections of two adjacent first array rods are in contact but not fixedly connected.

2. The vena cava filter according to claim 1, characterized in that: In the non-compressed state, the adjacent lower branch sections of two adjacent first array rods have mutually abutting and contacting closing sections, or the adjacent lower branch sections of two adjacent first array rods cross and overlap.

3. The vena cava filter according to claim 1, characterized in that: The side branch section is provided with a spherical body or a nearly spherical body at the end of the tail section, the diameter of which is greater than the width of the tail section.

4. The vena cava filter according to claim 1, characterized in that: The bending portion comprises a lead-out section, the width of the lead-out section gradually increases along the outward extension direction of the rod after bending, and then the side branch section and the lower branch section are separated.

5. The vena cava filter according to claim 1, characterized in that: The deflection angle of the end of the side branch segment relative to the starting end thereof is greater than 180 degrees.

6. The vena cava filter according to claim 1, characterized in that: The first array rods are made by integrally cutting a tube and then shaping it.

7. The vena cava filter according to claim 1, characterized in that: The side branch section is coplanar with the central axis, and the two lower branch sections are respectively located on both sides of the coplanar surface.

8. The vena cava filter according to claim 1, characterized in that: The included angle between the extension direction of the upper branch segment and the central axis is greater than the included angle between the extension direction of the lower branch segment and the central axis.

9. The vena cava filter according to claim 1, characterized in that: The pressure contact segment that tends to be parallel to the central axis means that the angle between the pressure contact segment that is substantially a straight line and the central axis is not greater than 15 degrees.

10. The vena cava filter according to claim 1, characterized in that: The arc-shaped curved section has a lowest point along the central axis, and the lowest point is located between two ends of the arc-shaped curved section.

Images