An implantable intraluminal filter

Abstract

This invention relates to the field of implantable medical device technology, and in particular to an intracavitary implant structure, especially a vena cava filter. Specifically, it discloses an intracavitary implant structure and a vena cava filter having the structure, including a central part with a central axis and a peripheral functional part consisting of several rods extending outward from the central part. By improving the arrangement, structure and shape of the rods constituting the functional part, the implant has better neutralization and other effects.

Description

Technical Field

[0001] This invention relates to the field of implantable medical device technology, and in particular to an intraluminal implant, especially a vena cava filter. Background Technology

[0002] Implantable medical devices are those that can remain in the body for short or long periods to support or maintain life, posing potential risks to the human body, and whose safety and effectiveness must be strictly controlled. 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 human cavities through interventional procedures. After the compressed device is released and expanded at the desired location in the body, it achieves therapeutic effects, such as expanding, supporting, occluding, reducing the volume of blood vessels or body cavities, or preventing the flow of blood clots.

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

[0004] However, achieving a good neutralization effect may be difficult. A typical example is the parachute-shaped vena cava filter, such as the Gunther Tulip manufactured and sold by William Cook. TM Filter and Electron TM Filters, with relevant literature such as US5324304A and CN101031254A. This type of filter mainly consists of a self-expanding umbrella-shaped filtration section composed of slender supports arranged or woven together to block thrombi in veins. At least one end of the slender supports is gathered at the central position of the umbrella-shaped body, where a release or retrieval section, such as a retrieval hook, is usually provided to release or retrieve the umbrella-shaped body in conjunction with a retrieval device such as a sheath.

[0005] The parachute-shaped inferior vena cava filter lacks effective restraint near the retrieval hook, resulting in a higher probability of filter tilting during and after implantation. Filter tilt is defined as an angle >15° between the filter's longitudinal axis and the central longitudinal axis of the inferior vena cava. Severe filter tilt can cause the retrieval hook to adhere to or become stuck to the wall of the inferior vena cava, leading to uneven umbrella-shaped unfolding, resulting in serious events such as inability to retrieve the filter, reduced thrombus filtration efficiency, and perforation. The causes of filter tilt may be related to factors such as the pulsation of the main vein, gastrointestinal peristalsis, the anatomical morphology of the inferior vena cava itself, and the placement of the filter.

[0006] Improved filter structures have been disclosed, such as in patent publications US20100049239A1, WO2018120414A1, CN105193521A, and CN102470028A. These designs incorporate a limiting mechanism near the recovery hook, which improves filter tilt and neutralization. However, these improved filter structures still have some drawbacks. For example, the limiting mechanism is typically composed of rods attached to the filter. While longer or more numerous rods can improve neutralization, they also significantly increase the difficulty of filter release. In particular, more rods complicate the control and adjustment of the filter release posture. Positional deviations of the first released rod can amplify the positional deviations of the subsequent released rods, and this phenomenon becomes increasingly unavoidable as the distance between the two rods along the filter's axial direction increases. Another typical scenario involves a delivery sheath containing the filter that is not coaxial with the lumen of the vein. In this case, the extension space of the rods as they are released from the delivery sheath into the vein varies in different directions. Rods closer to the inner wall of the vein are more likely to deflect laterally or exhibit abnormal release patterns. These situations can exacerbate filter tilting or uneven distribution of the filter rods within the vein, ultimately leading to filter retrieval failure, reduced thrombus filtration efficiency, and various complications.

[0007] In addition, the presence of more rods in the filter increases resistance when it is released from the sheath, and the release operation within the body cavity is difficult to perform with large forces due to its delicate nature, further reducing the controllability of the release operation.

[0008] Filter release is typically achieved by manipulating the delivery cable and delivery sheath. The filter is detachably connected to the delivery cable and is embedded within the delivery sheath. Within the lumen (e.g., an inferior vena cava filter), the relative sliding of the delivery cable and delivery sheath is manipulated to release the filter from the delivery sheath into the lumen. After expansion, the filter is positioned within the lumen, and finally, the delivery cable is detached. This process usually includes a pre-release observation and adjustment step, where the filter is released within the lumen but not disconnected from the delivery cable. X-ray transmission or angiography allows for detailed observation of the filter's deployment and positioning within the lumen. In certain cases, filters with unsatisfactory release posture or position can be reinserted into the delivery sheath. During the aforementioned steps, it is desirable to slightly adjust the filter's position and posture within the lumen by manipulating the delivery cable. This may avoid the aforementioned reinsertion into the delivery sheath, and in particular, adjustments can lead to better therapeutic outcomes and reduce the risk of complications after filter implantation. Summary of the Invention

[0009] The present invention provides an implantable filter, particularly an inferior vena cava filter, which has features that address or improve one or more of the above-mentioned disadvantages.

[0010] This invention provides an implantable filter for use in a lumen, comprising:

[0011] A central component that can be detachably connected to a conveying device for conveying the filter within the lumen;

[0012] Multiple anchoring and filtering components are spaced around the central component and are limited by the central component to achieve positioning and filtration within the cavity;

[0013] The filter has both an unrestrained state and a radially compressed implanted state.

[0014] The anchoring member and the filter member are configured to undergo elastic deformation under compressive load in the implanted state, and satisfy that, under the same radial dimension after compression, the radial elastic force of the anchoring member is greater than that of the filter member.

[0015] The anchoring component and the filter component have different radial elastic forces, which provides the possibility of different operations for the release control of different components. In particular, the radial elastic force of the anchoring component is greater, and its spontaneous response during the release and attitude adjustment of the filter is the main controlled object. This helps the operator to obtain the desired filter positioning position and positioning direction in the cavity by operating the conveying device. For example, when the filter is released into the cavity and is not disconnected from the conveying device, the position and attitude of the filter can be slightly adjusted by operating the conveying device.

[0016] In addition, since both the filter component and the anchoring component are limited by the central component, the position and orientation of the filter component with a smaller radial elastic force after being released in the cavity are affected by the positioning of the anchoring component. That is, the distribution of the filter component in the cavity can also be indirectly adjusted, which is more advantageous when there are a large number of filter components, and reduces the difficulty of adjusting the filter components.

[0017] It should be understood that the aforementioned anchoring components and filter components are distinguished by their primary functions. Anchoring components are anchored to the tube wall, primarily positioning and orienting the filter within the tube to prevent migration or tilting. The spatial arrangement of multiple filter components within the tube mainly achieves the desired filtration effect. However, under normal circumstances, anchoring components, being placed within the tube, may also contribute to partial filtration, and the pressure contact between filter components and the inner wall of the tube may also provide partial anchoring or positioning.

[0018] This invention provides a preferred embodiment in which the plurality of anchoring members and filter members are arranged in layers along the axial direction of the filter. The plurality of anchoring members are arranged in one layer, forming an anchoring portion with an outer diameter, and the plurality of filter members are arranged in another layer, forming a filter portion with an outer diameter. This layered arrangement provides more space for the spatial arrangement of the filter members, thereby facilitating better filtration and reducing the risk of entanglement between the anchoring and filter members. Furthermore, the position and orientation of the anchoring members, when adjusted by an adjustment force, are more uniform in a single layer.

[0019] In addition, the relative positions of the anchoring component and the filtering component within the lumen can usually be distinguished. In the direction of blood flow within the implanted lumen, the filtering component should first respond to the blood flow in order to achieve the filtering effect.

[0020] In a further preferred embodiment, the anchoring portion is closer to the central component than the filtering portion. From a maneuverability perspective, the single-layered anchoring members allow for more precise application of adjustment forces, improving the responsiveness of the anchoring portion to the conveying device's adjustment performance and enhancing the overall filter's attitude and position adjustment effectiveness.

[0021] Typically, the multiple anchoring structures within the anchoring section are symmetrically arranged, as are the multiple filtering structures within the filtering section. This allows for more uniform circumferential compressive force distribution within the tube for both the anchoring and filtering sections, resulting in more stable filter placement.

[0022] In a preferred embodiment of the present invention, when the filter is in an unrestrained state, the outer diameter of the anchoring portion is smaller than the outer diameter of the filtering portion. This ensures that the multiple filtering components have sufficient deformation to form and maintain the filtering functional configuration when the filter is in the implanted state. Furthermore, this arrangement allows the filtering components to have greater deformation and displacement relative to the anchoring components when compressed to the same diameter. Even a small adjustment to the anchoring component can result in a correspondingly larger adjustment to the filtering components, thus improving the ability to indirectly manipulate the filtering components.

[0023] In a preferred embodiment of the present invention, a connecting portion is provided at one end of the central component along the filter axial direction for connection with the conveying device; a retrieval portion is provided at the other end of the central component, which can be captured by a retrieval device for removing the implanted filter within the lumen. After the filter has been implanted in the lumen for a certain period, removal from the lumen may be considered. The retrieval portion and the connecting portion are designed to face each other, facilitating the retrieval operation. Furthermore, along the filter axial direction, the anchoring portion and the filtering portion are located on one side of the connecting portion of the central component, further avoiding direct interference of the anchoring portion and the filtering portion with the retrieval operation, providing greater operating space within the lumen for the retrieval operation, and reducing the difficulty of retrieval.

[0024] In an optional embodiment, the central component is a hub, the connecting part of which is a thread provided on the inner circumference of the hub, which can be threadedly connected to the conveying device; the recovery part is a hook-shaped body formed by slotting the hub or a hook-shaped body attached to the hub, which can be captured by a recovery device with a collar.

[0025] In a preferred embodiment of the present invention, the anchoring member has a load-buffering structure with a curved configuration for buffering compressive loads. During implantation, the compressive load on the filter from the lumen varies. The load-buffering structure can buffer the impact of the compressive load on the anchoring member, especially at the location where the anchoring member is confined, reducing the risk of fatigue fracture. Furthermore, the load-buffering structure provides more adjustment space for the attitude and position of the anchoring member within the lumen, and in particular, can effectively improve the contact mode between the anchoring member and the inner wall of the lumen.

[0026] In one embodiment of the invention, the anchoring member extends substantially in the axial and radial directions of the filter, but not substantially in the circumferential direction, and the load-bearing structure formed by the bending configuration therein also extends substantially in the axial and radial directions of the filter.

[0027] In one embodiment of the present invention, the anchoring member and the filter member are arranged in corresponding groups. The anchoring member and the filter member in each group are connected by a coupling member, so that the anchoring member and the filter member in each group are linked together and can be actuated by each other through the coupling member.

[0028] The linkage between the anchoring and filtering components within each group can refer to:

[0029] The elastic deformation of the anchoring components within each group actuates the filtering and coupling components;

[0030] Or / and, the elastic deformation of the filter structure within each group actuates the anchoring and coupling components.

[0031] Preferably, the anchoring member or filtering member is actuated at least in the radial direction of the filter.

[0032] An actuation relationship is formed between the anchoring component and the filter component, further enhancing the ability to indirectly control and adjust the filter component.

[0033] It should be understood that the anchoring components or filtering components of the above groups are not directly fixedly connected; otherwise, the actuation effect within the group cannot be formed.

[0034] In one embodiment, the anchoring members and filtering members within the assembly are staggered along the circumferential direction of the filter. In the implanted state, the anchoring members and filtering members provide elastic forces in different radial directions. This staggered arrangement further improves the stability of the filter within the lumen during implantation.

[0035] In a preferred embodiment of the above filter solution, the anchoring member, the filtering member, and the coupling member are all rod-shaped members;

[0036] The coupling member extends from the central part and away from the central part to its end. Each coupling member then extends an anchoring member and two filter members from its end, with the anchoring member located between the two filter members.

[0037] In a further improvement, the coupling member has a bend near its end, and the angle between the coupling member and the axial centerline of the central portion decreases in the direction toward its end after passing through the bend.

[0038] The filter element extends axially downwards from the bend in the filter, and two adjacent filter elements extending from adjacent coupling elements extend toward each other. The two adjacent filter elements extending toward each other may not form contact, but preferably form movable contact. For example, in the implanted state, the contact position between the two adjacent filter elements may change with load variations, but a small change in contact position is generally desirable.

[0039] In a further improvement, the anchoring member is basically coplanar with the coupling member from which it is derived, and the anchoring member extends towards its tail section in a generally U-shaped or V-shaped curved configuration, forming a load buffer structure.

[0040] The addition of a bend in the coupling component further enhances the load buffering effect of the U-shaped or V-shaped load buffer structure of the anchoring component within the group, allowing the anchoring component to bear more of the load. On the one hand, the anchoring component can respond to the dynamic load applied to the inner wall of the lumen more quickly, resulting in better long-term anchoring performance in the implanted state. At the same time, the overall positional change of the filter in response to dynamic loads is also smaller. On the other hand, the reduced load on the coupling component results in lower stress at the root of the coupling component, which can significantly reduce the risk of fatigue fracture at the root of the coupling component.

[0041] A further improvement is that the tail section of the anchoring member is positioned above the bend along the filter's axial direction and tends towards the central component. This reduces the risk of the anchoring member expanding and piercing the inner wall of the lumen when the filter is released within the lumen.

[0042] A further improvement is that the width of the anchoring member and the filter member is smaller than the width of the coupling member, and the length of the anchoring member is smaller than the length of the filter member but larger than the length of the coupling member. The relatively larger width of the coupling member can improve the stability of the filter configuration in the implanted state and further improve the load-bearing capacity of the anchoring member.

[0043] In one preferred embodiment of the filter of the present invention, both the anchoring member and the filtering member are non-invasive structures that do not penetrate the inner wall of the lumen. Neither the anchoring member nor the filtering member has any structure that could cause damage to the inner wall of the lumen. Common structures that could cause damage to the inner wall of the lumen include, for example, anchor spikes, sharp ends of rods, or hooks.

[0044] One preferred embodiment of the filter of the present invention is a thrombus filter that can be implanted in the inferior vena cava.

[0045] In one preferred embodiment of the filter of the present invention, the anchoring member and the filtering member are configured to have different radial compression ratios for the same radial dimension after compression, wherein the anchoring member has a radial compression ratio of less than 30% and the filtering member has a radial compression ratio of more than 50% when the radial dimension after compression is 18-32 mm.

[0046] The radial compression ratio is the ratio of the difference in radial length before and after compression to the radial length before compression.

[0047] Preferably, the radial elastic force of the anchoring member is 2 to 8 times that of the radial elastic force of the filter member.

[0048] For example, the radial elastic force of the anchoring component can be 0.2-0.8 N, and the radial elastic force of the filter component can be 0.05-0.2 N.

[0049] In summary, the present invention provides an implantable filter that has better maneuverability. The posture and position of the filter in the implanted state are easy to adjust. At the same time, the better structural design helps to improve the filter's centering, anti-migration ability, anti-tilting ability, fatigue fracture resistance, and recyclability in the lumen, thereby improving the treatment effect and reducing the risk of complications.

[0050] Another aspect of the invention is to provide another implantable lumen filter, which may include:

[0051] A central component that can be detachably connected to a conveying device for conveying the filter within the lumen;

[0052] Multiple anchoring and filtering components are spaced apart around the central component and are limited by the central component to achieve positioning and filtration within the cavity;

[0053] The plurality of anchoring members and filter members are arranged in layers along the axial direction of the filter, wherein the plurality of anchoring members are arranged in one layer to form an anchoring part with an outer edge diameter, and the plurality of filter members are arranged in another layer to form a filter part with an outer edge diameter.

[0054] The radial support force of the anchoring part is greater than the radial support force of the filter part.

[0055] The number of anchoring members constituting the anchoring part may not be greater than the number of filtering members constituting the filtering part.

[0056] The anchoring member and the filter member are configured to undergo elastic deformation under compressive load in the implanted state, and satisfy that, under the same radial dimension after compression, the radial elastic force of the anchoring member is greater than that of the filter member.

[0057] Unless otherwise specified, the radial elastic force referred to in this invention generally refers to the mechanical test results of a single component, while the radial support force referred to in this invention generally refers to the force applied to the cavity or circumferential compression device by the aforementioned anchoring part or filter part as measured.

[0058] Another aspect of the present invention is to provide an intracavitary implant structure applicable to the aforementioned implantable intracavitary filter, 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, the outer periphery of the functional portion being compressible around the central axis.

[0059] The functional part can at least serve as a positioning structure for the implant. The functional part is compressible to make it elastic, and by utilizing its tendency to recover its uncompressed elastic force when compressed, the implant can be anchored within a human lumen, such as a blood vessel. In the anchored state, the central axis can be positioned towards the center of the human lumen, or the functional part can conform to the shape of the human lumen.

[0060] At least one rod has a bent portion protruding outward from the functional part, and is divided into an upper support section and a lower support section above and below the bent portion, with different angles from the central axis. The rod also has an outwardly extending side support section near the bent portion. In the non-compressed state, the farthest end of the side support section from the central axis is located between the end of the lower support section and the bent portion.

[0061] In one embodiment of the present invention, the side branch is coplanar with the central axis, and two lower branches extend from below the bent portion, the two lower branches being located on opposite sides of the coplanar portion.

[0062] In one embodiment of the present invention, the angle between the extension direction of the upper branch and the central axis is greater than the angle between the extension direction of the lower branch and the central axis.

[0063] In one embodiment of the present invention, the side branch includes an upwardly extending arcuate bend, the end of the arcuate bend having a deflection angle greater than 90 degrees relative to its starting end.

[0064] In a preferred embodiment of the present invention, the radius of curvature of the arc-shaped curved segment gradually increases towards its end.

[0065] In a preferred embodiment of the present invention, the side branch further includes a straight section, which is substantially parallel to the lower branch and extends from the bending portion before transitioning into the arc-shaped curved section.

[0066] In a preferred embodiment of the present invention, there are at least two lower support segments, which are arranged along the width direction of the rod together with the straight segment located therebetween.

[0067] In a preferred embodiment of the present invention, the portion of the arc-shaped curved segment near its end is substantially parallel to or nearly parallel to the central axis.

[0068] In one embodiment of the present invention, the side branch further includes a tail section extending from the end of the arc-shaped curved section, the tail section pointing in the direction of the central axis, and the width of the tail section being smaller than the width of the other parts within the arc-shaped curved section.

[0069] The tail section may have a flanged spherical structure with a spherical or similar end.

[0070] In some embodiments of the present invention, the width of the upper branch is greater than the width of the lower branch and the side branch, respectively. The arc-shaped curved section of the side branch includes a parallel section 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 section gradually increases from its starting end to the end of the pressure contact section. After the parallel section, a curved tail section extends towards the center, and the width of the tail section is smaller than the width of other sections within the side branch. This variation in width can reduce the resistance when the rod is retracted into or released from the sheath, improving the operability of the implant during release and retrieval. The width treatment of the tail section can effectively prevent the side branch from getting stuck at the sheath orifice when retracted into the sheath, because when an intravascular implant is retrieved, it is almost impossible for its central axis to coincide with the central axis of the sheath orifice. At least some side branches will inevitably be retracted into the sheath orifice in an inclined posture, which makes the phenomenon of side branches getting stuck at the sheath orifice highly common.

[0071] In optional embodiments of the present invention, the intracavitary implant structure may also have one or more of the following structural features in any combination:

[0072] Structure 1: The straight section forms an angle with the central axis;

[0073] Structure 2, the arc-shaped curved segment has a lowest point along the central axis, the lowest point being located between the proximal and distal ends of the arc-shaped curved segment;

[0074] Structure 3: The distal end of the arc-shaped curved segment deflects at an angle of no more than 180 degrees relative to its proximal end.

[0075] Structure 4: The distal end of the side branch has a deflection angle greater than 180 degrees relative to its proximal end.

[0076] In an alternative embodiment of the present invention, the rods constituting the functional part are not fixedly connected.

[0077] Another aspect of the present invention is to provide a vena cava filter having the endovascular implant structure as described above.

[0078] The functional section has its bars evenly distributed circumferentially to prevent thrombi in the vena cava from passing through it.

[0079] In one embodiment of the present invention, each rod of the functional part extends two counter-extending lower branches at the bending portion, and in the compressed state, adjacent rods abut or cross each other through the two adjacent lower branches, so that the functional part forms a mesh structure.

[0080] The two lower branches enhance peripheral support, and their offset from the para-branch reduces release resistance. After implantation, the filter undergoes endothelialization, with the endothelium covering the implanted rod, making retrieval difficult, increasing vascular damage, and potentially rendering it unretrievable. The non-fixed connection between the two lower branches allows for greater freedom of movement, facilitating extraction from the endothelial tissue and reducing vascular damage. Furthermore, the contact between the two lower branches improves rod support and morphological stability, ensuring the filter remains stably positioned within the vessel for optimal release and preventing migration.

[0081] In one embodiment of the present invention, in the uncompressed state, two adjacent lower branches of the adjacent rods abut each other at a distance from their ends.

[0082] Another aspect of the present invention is to provide another structure of an intracavitary implant or an intracavitary implant having such a structure, which is applicable to the aforementioned implantable intracavitary filter, comprising a central portion having a central axis and a peripheral functional portion consisting of a plurality of rods extending outward from the central portion, said functional portion being compressible.

[0083] The functional part can at least serve as a positioning structure for the implant. The functional part is compressible to make it elastic, and by utilizing its tendency to recover its uncompressed elastic force when compressed, the implant can be anchored within a human lumen, such as a blood vessel. In the anchored state, the central axis can be positioned towards the center of the human lumen, or the functional part can conform to the shape of the human lumen.

[0084] In a non-compressed state, the functional part of the present invention includes at least a first outer periphery, a second outer periphery, and a third outer periphery, which are formed by the flanges or free ends of a plurality of rods arranged around the central axis. The first outer periphery, the second outer periphery, and the third outer periphery are arranged outward from the center and are not coplanar with each other. The first outer periphery and the second outer periphery are closer to the center along the central axis than the third outer periphery.

[0085] The flange or free end of the rod can be compressed and moved toward the central axis, and the compression of the second and third outer peripheries can cause the implant to be positioned and held in a first posture within the cavity in which it is implanted.

[0086] When any one or more flanges or free ends constituting the first outer periphery are compressed, the implant can be positioned and held in the first posture within the cavity in which it is implanted.

[0087] Clearly, the flange refers to the outward direction of the functional part to provide a possible support point when the implant is anchored.

[0088] The second and third outer peripheries constitute two layers of support sites distributed along the long axis of the cavity of the functional part. They can contact the inner wall of the cavity into which the implant is inserted. Compared to the uncompressed state, the second and third outer peripheries are subjected to the pressure of the inner wall of the cavity, which can resist the tilting of the central part or the central axis towards the inner wall of the cavity, maintaining a certain distance between the central part and the inner wall of the cavity, forming the desired first posture. When the support function of the flange or free end of any one or more rods of the second outer periphery is lost due to various factors, such as the flange or free end shifting to its side, its support function is lost or weakened. The flange or free end of the rod of the first outer periphery near the support site can abut against the inner wall of the cavity, forming a second posture, resisting the tilting of the central part or the central axis towards the side where the offset support site is located, preventing the central part from sticking to the wall. That is, the implant can keep the second posture as close as possible to the first posture.

[0089] 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 their corresponding flanges or free ends constituting the second outer periphery may be substantially located in the same radial direction. For example, a preferred embodiment of the one-to-one correspondence may mean that one flange or free end constituting the first outer periphery and its corresponding other flange or free end constituting the second outer periphery are substantially located in the same radial direction.

[0090] In one embodiment, the first outer periphery is located between the second and third outer peripheries along the central axis. Alternatively, the second outer periphery is located between the first and third outer peripheries along the central axis.

[0091] In one embodiment, the first outer periphery is formed by the flange of the rod.

[0092] Optionally, either outer periphery may be formed by a flange or a free end. For example, both the third and second outer peripheries may be formed by the free end, or the third outer periphery may be formed by the free end and the second outer periphery may be formed by the flange.

[0093] The aforementioned rods constituting the outer periphery may include at least a first array rod and a second array rod.

[0094] In one embodiment, the third outer periphery is formed by the arrangement of the free ends of the first array rods, and the second outer periphery is formed by the arrangement of the free ends or flanges of the second array rods.

[0095] In one embodiment, the third outer periphery is formed by the arrangement of the free ends of the first array rods, the first array rods are further provided with branches, and the second outer periphery is formed by the arrangement of the free ends or flanges of the branches of the first array rods.

[0096] In a further improvement, the first array rod is also provided with a flange, and the first outer periphery is formed by the flange of the first array rod. For example, each of the first array rods has a bent portion, and the front and rear sections of the first array rod form an angle at the bent portion, with the bent portion of the first array rod forming the flange.

[0097] In one embodiment, the rod containing the free end or flange constituting the second outer periphery has a curved section extending in a direction away from the third outer periphery, the end or protruding end of the curved section constituting the free end or flange of the second outer periphery.

[0098] Preferably, the second outer periphery approaches the first outer periphery radially.

[0099] Optionally, the first outer periphery, the second outer periphery, and the third outer periphery are all located on the same side of the center.

[0100] Preferably, the flange or free end has a smooth curved surface and can contact the inner wall of the cavity where the implant is inserted through the smooth curved surface.

[0101] 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.

[0102] In 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, with each pair of flanges or free ends constituting the third outer periphery and the flanges or free ends constituting the second outer periphery being staggered along the central axis in the circumferential direction.

[0103] Preferably, each rod of the functional part is made by integrally cutting a tube and then shaping it.

[0104] Another aspect of the present invention is to provide a vena cava filter having an intracavitary implant structure as described above, wherein the bars of the functional portion are evenly distributed circumferentially to prevent thrombi in the vena cava from passing through the functional portion.

[0105] Another aspect of the present invention provides a retrievable intracavitary implant structure or a retrievable intracavitary implant having the structure, comprising a central portion having a central axis and a plurality of rods extending outward from the central portion and arranged around the central axis, wherein the implant is positioned and held within the cavity in which it is implanted by compression of the functional portion by the cavity wall.

[0106] The functional part can at least serve as a positioning structure for the implant. The functional part is compressible to make it elastic, and by utilizing its tendency to recover its uncompressed elastic force when compressed, the implant can be anchored within a human lumen, such as a blood vessel. In the anchored state, the central axis can be positioned towards the center of the human lumen, or the functional part can conform to the shape of the human lumen.

[0107] At least one of the rods includes an arc-shaped curved section, the radius of curvature of which gradually increases from its proximal end near the center to its distal end.

[0108] In one embodiment of the present invention, the radius of curvature gradually increases, and the arc-shaped curved section becomes straighter towards its distal end, resulting in less resistance when retracting into the sheath.

[0109] In one embodiment of the present invention, the arc-shaped curved segment is substantially parallel to or nearly parallel to the central axis near its distal end.

[0110] In one embodiment of the invention, the rod further extends into a tail section at the distal end of the arc-shaped curved section.

[0111] In one embodiment of the present invention, the tail section is parallel to or bent toward the central axis.

[0112] In one embodiment of the present invention, the end of the rod is a spherical or similar spherical body with a flanged spherical structure.

[0113] In one embodiment of the present invention, the rod generally exhibits a trend of decreasing width towards its end.

[0114] In one embodiment of the invention, the diameter of the spherical or spherical end of the rod is greater than the width of its adjacent segment. For example, the width of the tail segment is smaller than the width of the curved segment.

[0115] In one embodiment of the present invention, the rod is further provided with a straight section on the proximal side of the arc-shaped curved section, the rod extends from the straight section out of the arc-shaped curved section, and the straight section forms an angle with the central axis.

[0116] In one embodiment of the present invention, the arc-shaped curved segment has a lowest point along the direction of the central axis, the lowest point being located between the proximal and distal ends of the arc-shaped curved segment.

[0117] 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 its proximal end.

[0118] Another aspect of the present invention is to provide a vena cava filter having the aforementioned retrievable intracavitary implant structure.

[0119] In summary, the intraluminal implant structure and the implantable filter having the structure, such as the inferior vena cava filter, of the embodiments of the present invention can improve performance in terms of neutrality, delivery, safety and ease of operation.

[0120] In embodiments of the present invention, the intraluminal implant, such as a filter that can be implanted into the lumen, can serve as a retrievable device, and can have the effects of a longer implantation period, a higher success rate of retrieval, and less damage to the vena cava. Attached Figure Description

[0121] Figure 1 and Figure 2 This is a schematic diagram of a single rod in two embodiments of the implant structure of the present invention;

[0122] Figure 3-9 This is a schematic diagram of two symmetrical rods in different implantation structures of the present invention;

[0123] Figure 10-12 These are views along the central axis of three implant structure embodiments of the present invention;

[0124] Figure 13 and Figure 14 These are schematic diagrams from different directions of a preferred embodiment of the vena cava filter of the present invention;

[0125] Figure 15 for Figure 13 Enlarged view of a portion of the image;

[0126] Figure 16 and Figure 17 These are two different effect diagrams after the preferred embodiment of the vena cava filter of the present invention is released into the implantation cavity;

[0127] Figure 18 and Figure 19 The figures show finite element analysis diagrams simulating the forces acting on the vena cava filter after implantation into the cavity, representing two different embodiments.

[0128] Figure 20a 20b and 20c are diagrams showing different deployment states of the aforementioned preferred embodiment of the inferior vena cava filter after delivery via the femoral vein to the subject, implanted into the inferior vena cava. It can be seen that the delivery cable remains connected to the filter. Figure 20a The shown portion of the vena cava filter shows the delivery sheath; the filter components remain bound by the delivery sheath and are not released. Figure 20b 20c shows the complete release of the delivery sheath from the vena cava filter, and... Figure 20bThe image shows that one of the filter's anchoring components did not deploy as ideally as intended within the inferior vena cava and requires adjustment.

[0129] The reference numerals in the accompanying drawings are explained as follows:

[0130] 1. Central part; 2. First array rod; 21. Upper support section; 211. Bending part; 22, 221, 222. Lower support section; 23. Side support section; 31. First outer perimeter; 32. Second outer perimeter; 33. Third outer perimeter; 4. Second array rod; 5. Inner wall of the cavity. Detailed Implementation

[0131] One type of existing intracavitary implant structure includes a central portion with a central axis and a functional portion with an outer periphery consisting of several rods extending outward from the central portion. The outer periphery of the functional portion surrounds the central axis and can be compressed towards the central axis by the inner wall of the cavity, thereby positioning and maintaining the implant within the cavity in which it is implanted. A typical implant structure of this type can be found in the filter structure disclosed in WO2017186025A1 by the inventors of this application, the entire contents of which are incorporated herein by reference. The aforementioned implant in a strongly compressed state has a small shape and volume and can be placed in a sheath and transported through the sheath into the body cavity. At the desired placement position, the implant is released from the sheath by the surgeon's manipulation. The aforementioned implant in a strongly compressed state expands and tends towards a non-compressible state. Its functional rods expand away from the central axis and press against the inner wall of the implanted cavity. The multiple rods form circumferential support for the implant. At this time, the functional portion expands relative to its strongly compressed state and remains in a weakly compressed state, thereby positioning and maintaining the implant within the cavity in which it is implanted.

[0132] However, the above description is not restrictive, and intracavitary implants disclosed in CN1399530A, CN1842354A, CN105208947A, etc., also have similar structures.

[0133] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation details.

[0134] Intracavitary implant structure

[0135] One object of the present invention is to provide an improved intracavitary implant structure, wherein, in a non-compressed state, the functional part includes at least a first outer periphery 31, a second outer periphery 32, and a third outer periphery 33, which are formed by the flanges or free ends of a plurality of rods arranged around a central axis. The first outer periphery 31, the second outer periphery 32, and the third outer periphery 33 are arranged sequentially outward from the central part 1 and are not coplanar with each other. The first outer periphery 31 and the second outer periphery 32 are closer to the central part 1 along the central axis direction than the third outer periphery 33.

[0136] The flange or free end of the rod can be compressed and moved toward the central axis, and the compression of the second outer periphery 32 and the third outer periphery 33 can make the implant be positioned and held in a first posture within the cavity in which it is implanted.

[0137] When any one or more flanges or free ends constituting the first outer periphery 31 are compressed, the implant can be positioned and maintained in a first posture within the cavity where it is implanted.

[0138] The flange faces outward from the functional part.

[0139] In this embodiment of the invention, the flange can be a bent portion 211 of the rod, facing outwards from the functional part. (See reference...) Figure 1-9 Alternatively, it can be the farthest point of the curved segment from the central axis, as referenced. Figure 15 The segment has a radius of curvature of D2. However, without limitation, those skilled in the art may choose other forms of flanges, which can serve as support points, contacting the inner wall of the implanted cavity to limit and support the implant. The flange is preferably the bent portion 211 of the rod, see reference... Figure 1-9 or Figure 13 The bend 211 has a non-arc-shaped bend, which creates a relatively fixed angle between the top and bottom of the rod. This reduces the transmission of compressive force 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 bend 211 decreases due to pressure on the end of the rod, thus buffering or reducing the force transmitted to the root of the rod. At the same time, the lower branch extending from below the bend 211 provides support for the end of the rod. This lower branch has greater elastic recovery force due to the smaller angle of the bend 211, thus providing stronger support and positioning for the implant within the implantation cavity.

[0140] Continue to refer to Figure 15 and Figure 16 The segment with a radius of curvature D2 can be a pressure contact segment that is substantially parallel to or tends to be parallel to the central axis, and can press against the inner wall of the implanted cavity to support or stabilize 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 substantially straight, has an angle with the central axis of no more than 15 degrees. This design is beneficial because, during implant retrieval, the pressure contact segment is retracted into the retrieval sheath, reducing the retrieval resistance to implant deformation caused by the inner wall of the body cavity and the retrieval sheath opening. It also allows the pressure contact segment to provide a larger contact area with the inner wall of the body cavity during implantation, improving the stability of the anchoring effect.

[0141] See Figure 10-12The illustration shows three implant structure embodiments of the present invention, each having a first outer periphery 31, a second outer periphery 32, and a third outer periphery 33 formed by the flange or free end of a rod, with radii of a, b, and c respectively. Figure 12 The shape of each rod in the functional part of the implant can be: Figure 7-9 Any one of them, Figure 10 The shapes of the rods in the functional components of the implant shown in Figure 11 can be as follows: Figure 1-6 Any one of them. Figure 10 and Figure 11 The main difference between the functional parts of the implant lies in the number and shape of the lower support segments of the rod.

[0142] The second outer periphery 32 and the third outer periphery 33 constitute two layers of support sites distributed along the long axis of the cavity of the functional part. They can contact the inner wall of the cavity into which the implant is inserted. Compared with the non-compressed state, the second outer periphery 32 and the third outer periphery 33 are subjected to the pressure of the inner wall of the cavity, which can resist the tilting of the central part 1 or the central axis towards the inner wall of the cavity, and maintain a certain distance between the central part 1 and the inner wall of the cavity, forming the desired first posture. When the support function of the flange or free end of any one or more rods of the second outer periphery 32 is lost due to various factors, such as the flange or free end shifting to its side, its support function is lost or weakened. The flange or free end of the rod of the first outer periphery 31 near the support site can abut against the inner wall of the cavity, forming a second posture, resisting the tilting of the central part 1 or the central axis towards the side where the offset support site is located, preventing the central part 1 from sticking to the cavity wall. That is, the implant can keep the second posture as close as possible to the first posture.

[0143] However, the above description is not limiting. After the implant is released from the cavity via the sheath, it may directly assume the second position instead of the first position. In this case, the first position can be the ideal implantation state desired by the surgeon. For example, the implant may be released when the sheath and the cavity have poor alignment along their long axis.

[0144] As a non-limiting possibility, another possibility is that the peristalsis, contraction, etc. of the cavity cause changes in the position or shape of the implanted implant, changing from the initial first posture to the second posture.

[0145] Figure 13 and 14 The image shown is a preferred embodiment of an implant according to the present invention, and its top view along the central axis of the central portion 1 is similar to... Figure 11 It has three peripheries. Figure 16 and 17 The image shows two postures of the implanted cavity. Figure 16 The implant orientation shown is typically the desired one. Figure 17At least one support point of the second outer periphery 32 fails due to lateral displacement, and the bend 211 of the rod constituting the first outer periphery 31 nearby acts as a support point. The implant posture avoids 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.

[0146] In 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. Figure 10 and Figure 11 A radially corresponding arrangement along the outer periphery is shown, wherein the number of flanges or free ends constituting the first outer periphery 31 is equal to the number of flanges or free ends constituting the second outer periphery 32, and the corresponding flanges or free ends of the two outer peripheries are substantially located in the same radial direction. This makes the first outer periphery 31 have a better support site replenishment effect, and the replenishment support for the failure sites of the second outer periphery 32 is more precise. The tilt angle of the filter can therefore be controlled to be smaller. Figure 12 Another non-radial correspondence is shown, in which any two adjacent flanges or free ends of the second outer periphery 32 correspond to a flange or free end of the first outer 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.

[0147] In a preferred embodiment, the first outer periphery 31 is located between the second outer periphery 32 and the third outer periphery 33 along the central axis direction. See [link / reference] Figure 1 and Figure 2 The distribution of the outer circumferences is shown. In other optional embodiments, the second outer circumference 32 is located between the first outer circumference 31 and the third outer circumference 33 along the central axis direction, for example... Figure 5 .

[0148] The third outer perimeter 33, the second outer perimeter 32, and the first outer perimeter 31 can all be formed by the free ends of the rods, for example, by the free ends of the first array rod 2, the second array rod 4, and the third array rod in sequence.

[0149] In a preferred embodiment, the first outer periphery 31 is formed by the flange of the rod, and both the third outer periphery 33 and the second outer periphery 32 are formed by free ends, or the third outer periphery 33 is formed by free ends and the second outer periphery 32 is formed by flanges. For example, the third outer periphery 33 is formed by the arrangement of the free ends of the first array rods 2, and the second outer periphery 32 is formed by the arrangement of the free ends or flanges of the second array rods 4, see reference. Figure 12 The shape of each rod can be Figure 7-9Any one of the following; for example, the third outer periphery 33 is formed by arranging the free ends of the first array rods 2, the first array rods 2 also having branches, and the second outer periphery 32 is formed by arranging the free ends or flanges of the branches of the first array rods 2, see reference. Figure 10 Or 11, the shape of the first array rod 2 and its branches can be Figure 1-9 Any one of them.

[0150] The first array rod 2 may also be provided with a flange, and the first outer periphery 31 is formed by the flange of the first array rod 2. For example, each of the first array rods 2 has a bent portion 211, and the front and rear sections of the first array rod 2 form an angle at the bent portion 211. The bent portion 211 of the first array rod 2 forms a flange. (See reference) Figure 1-6 .

[0151] The rod forming the free end or flange of the second outer periphery 32 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 forms the free end or flange of the second outer periphery 32. (Reference) Figure 1-4 and Figure 6 The first array rod 2 has branches, with a lower branch 22 and a side branch 23 extending from the upper branch 21. The side branch 23 has a curved section. Depending on the shape of the curved section, the end of the curved section can be used as a free end to form the second outer periphery 32, or the outermost protruding end of the curved section can be used as a flange to form the second outer periphery 32.

[0152] In a preferred embodiment, the second outer periphery 32 approaches the first outer periphery 31 radially. That is, the radial distance between the first outer periphery 31 and the second outer periphery 32 can be less than the radial distance between the second outer periphery 32 and the third outer periphery 33.

[0153] Optionally, the first outer periphery 31 and the second outer periphery 32 are located on both sides of the central portion 1, and the third outer periphery 33 is located on one side. However, preferably, the first outer periphery 31, the second outer periphery 32 and the third outer periphery 33 are all located on the same side of the central portion 1.

[0154] In a preferred embodiment, the flange or free end has a smooth curved surface and can contact the inner wall of the cavity where the implant is inserted through the smooth curved surface.

[0155] In a preferred embodiment, the number of flanges or free ends constituting the third outer periphery 33 is greater than the number of flanges or free ends constituting the second outer periphery 32. For example, Figure 11 The implant shown has two lower branches 221 and 222 branched from the bend 211 of the first array rod 2. Adjacent lower branches of two adjacent first array rods 2 can contact each other but are not fixedly connected. (Refer to...) Figure 12 , 16Or 19. In this case, the number of flanges or free ends constituting the third outer perimeter 33 is twice the number of flanges or free ends constituting the second outer perimeter 32, and the flanges or free ends constituting the third outer perimeter 33 are distributed in pairs. Each pair of flanges or free ends constituting the third outer perimeter 33 is staggered with the flanges or free ends constituting the second outer perimeter 32 along the central axis. See [reference needed]. Figure 14 .

[0156] The rods of the implant functional part of this invention are preferably made by integrally cutting and shaping tubing. The tubing can be shape memory materials such as stainless steel or nickel-titanium alloy, and the designed shape in a non-compressible state is obtained through heat setting.

[0157] • Rods constituting functional parts

[0158] In some embodiments of the implant of the present invention, among the multiple rods constituting the functional part, at least one rod is provided with a bent portion 211 protruding outward from the functional part, and is divided into an upper branch 21 and a lower branch 22 with different angles to the central axis above and below the bent portion 211. The rod is also provided with an outwardly extending side branch 23 near the bent portion 211. In the non-compressed state, the farthest end of the side branch 23 from the central axis is located between the end of the lower branch 22 and the bent portion 211.

[0159] by Figure 1 and Figure 2 Taking this example, the two figures illustrate two types of rods constituting the functional part. The distance from the farthest end of the side branch 23 to the central axis is b, the distance from the bent portion 211 to the central axis is c, and the distance from the end of the lower branch 22 to the central axis is a. Obviously, in the uncompressed state, a > b > c. In this embodiment, the side branch 23 includes an upwardly extending arc-shaped curved section. 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, providing support.

[0160] The rod containing the bent portion 211, within the implantation cavity, forms two support points along the long axis of the cavity through the distal end of the side branch 23 and the end of the lower branch 22. These points counteract the tilting of the central portion 1 towards the side of the rod on the cavity wall, maintaining a certain distance between the central portion 1 and the cavity wall. (See [reference]). Figure 12 Example.

[0161] When the collateral branch 23 is in its uncompressed lateral state due to various factors, its function as a support point may be lost. The bent portion 211 of the rod can abut against the inner wall of the lumen, resisting the tilting of the central portion 1 towards the side of the rod on the inner wall. Furthermore, at this time, the bent portion 211 and the lower branch 22 can abut against the inner wall as a whole, increasing the support area of ​​the rod and making the support of the functional part more stable. However, the unit pressure on the inner wall is weak, avoiding pressure injury or puncture to the vessel wall. See [link to relevant documentation]. Figure 17 Example.

[0162] Side support 23 can be provided where it extends from the bend 211 of the rod, see [reference]. Figure 1 and Figure 5 , Figure 1 The side branch segment 23 shown is an upwardly extending arc-shaped curved segment. Figure 5 The side branch segment 23 shown is a straight segment extending downwards.

[0163] Alternatively, the side branch 23 may be positioned near the bend 211 of the rod.

[0164] In one embodiment, the side branch 23 is derived from the upper branch 21, see [link to previous embodiment]. Figure 2 and Figure 4 , Figure 2 The side branch segment 23 shown can be an upwardly extending arc-shaped curved segment. Figure 4 The side branch segment 23 shown is a downward-extending arc-shaped curved segment.

[0165] In another embodiment, the side branch 23 can be derived from the lower branch 22, see [reference]. Figure 3 and Figure 6 .

[0166] Those skilled in the art can select different styles of the side branch 23 as needed, and are not limited to the embodiments of the present invention.

[0167] Figure 6 The structure and shape of the rod shown represent a preferred embodiment. The rod has an upper branch 21 extending from a central portion 1, and a lower branch 22 extending from a bend 211. A side branch 23 extends from the lower branch 22 and includes an arc-shaped bend. The end of the side branch 23 has a deflection angle greater than 180 degrees relative to its starting end, and its end points towards the central axis.

[0168] In a further preferred embodiment, the radius of curvature of the arc-shaped curved segment gradually increases towards its end. See also Figure 13 and Figure 15 , Figure 15The curved segment in the vessel consists of three segments with radii of curvature and diameters of D1, D2, and D3, respectively, increasing sequentially. This allows the collateral segment 23 to fit as closely as possible to the vessel wall. On one hand, the collateral segment 23 originates near the bend 211, allowing for a shorter length compared to its origin from the central portion 1, thus enhancing its resistance to deviation. On the other hand, the gradually increasing radius of curvature ensures that the collateral segment 23 makes line contact with the vessel wall rather than point contact.

[0169] The flange formed at the end or outermost end of the curved section can abut against the inner wall of the implanted cavity, providing support. The rod containing the bent portion 211, within the implanted cavity, forms two support points along the long axis of the cavity through the distal end of the side branch 23 and the end of the lower branch 22. This prevents the functional portion from tilting towards the inner wall of the cavity on the side where the rod is located, maintaining a certain distance between the central portion 1 and the inner wall of the cavity. (See [reference]). Figure 16 Example. When the collateral segment 23 is in its uncompressed lateral state due to various factors, its function as a support point may be lost. The bent portion 211 of the rod can abut against the inner wall of the lumen, thus preventing the functional part from tilting towards the inner wall in the direction of the rod. Furthermore, at this time, the bent portion 211 and the lower branch segment 22 can abut against the inner wall of the lumen as a whole, increasing the support area of ​​the rod and providing more stable support for the functional part, but the unit pressure on the inner wall of the lumen is weak, thus avoiding pressure injury or puncture to the inner wall of the blood vessel. See [link to example]. Figure 17 Example.

[0170] For further improvements, see Figure 13 and Figure 15 The side support section 23 also includes a straight section L, which extends from the bend 211 and transitions to an arc-shaped curved section, substantially parallel to the lower support section 22. There can be one, two, or more lower support sections 22, which can be configured as needed by those skilled in the art. In a preferred embodiment where there are at least two lower support sections 22, the side support section 23 is located between two lower support sections 221 and 222, and the straight section of the side support section 23 is arranged along the width direction of the rod with the lower support section.

[0171] Based on the above explanation, the side branch 23 may be coplanar with or not coplanar with the central axis. A non-coplanar side branch 23 may be more difficult to release and retrieve.

[0172] Figure 10 The side branch 23 shown is coplanar with the central axis, and a lower branch 22 is led out from the bend 211 of the rod where the side branch 23 is located. Figure 11 The side branch 23 shown is coplanar with the central axis. Two lower branches 221 and 222 are led out from the bent part 211 of the rod where the side branch 23 is located. The two lower branches 221 and 222 are located on both sides of the coplanar axis.

[0173] Figure 10 and Figure 11 The implant's functional portion is formed by the ends of the lower branches of six first array rods 2 arranged at equal intervals around the central axis to form a third outer 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 outer 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 outer periphery 31. Figure 12 The implant's functional part is composed of 6 first array rods 2 and 6 second array rods 4 alternating in the circumferential direction.

[0174] In the uncompressed state, it is preferable that the diameter of the third outer periphery 33 is 1.5-4 times the diameter of the second outer periphery 32, while the second outer periphery 32 approaches the first outer periphery 31 radially.

[0175] The upper support segment 21 and the lower support segment 22 may be curved or bent. Figure 11 , 13 As shown in Figure 14, both the lower support segments 221 and 222 have S-shaped curved sections.

[0176] in, Figure 10 The implant has six distal segments, while Figure 11 The implant can have 6 or 12 distal inferior limb segments. This is optional. Figure 8 The implant's two adjacent rods abut or intersect each other through adjacent lower branches, forming a mesh structure for the functional parts, while still retaining the 12 aforementioned ends as free ends. See [link to relevant documentation]. Figure 13 and Figure 14 However, another option, Figure 8 Each pair of adjacent rods of the implant is joined and fixed at one end by two adjacent lower branches, thereby allowing the implant to have six ends.

[0177] Based on the above description, the preferred embodiments of the present invention are as follows: Figure 1 and Figure 2 The angle α between the extension direction of the upper support segment 21 and the central axis is greater than the angle β between the extension direction of the lower support segment and the central axis. This structure, given a fixed maximum perimeter of the functional section, can have a relatively small height (i.e., length along the central axis), which is highly advantageous in most cases.

[0178] Preferably, the width of the functional rod in this invention decreases from the center 1 outwards.

[0179] For example, the width of the upper branch 21 is greater than that of the lower branch 22 (or 221, 222) and the side branch 23.

[0180] In a further preferred embodiment, the width of the side branch 23 generally decreases from its starting end to its ending end. For example, the side branch 23 is divided into two segments of different widths at the bottom of the upwardly extending arc-shaped curved section. The end of the narrower rear half can be provided with a spherical rounded head to avoid piercing the inner wall of the cavity.

[0181] In this invention, the length of the upper support segment 21 is preferably much smaller than the length of the lower support segment 22 (or 221, 222), and the length ratio can be 0.2-0.05.

[0182] Preferably, the end of the side branch 23 is located in or near the central part 1 along the central axis direction.

[0183] ·Vacuum filter

[0184] Another aspect of the present invention is to provide a vena cava filter having any of the aforementioned intracavitary implant structures, wherein the bars of the functional part are evenly distributed circumferentially to prevent thrombi in the vena cava from passing through the functional part.

[0185] See Figure 10-12 Three types of vena cava filters are shown.

[0186] Figure 13 , 14 In a preferred vena cava filter provided by the present invention, each rod of the functional part has two counter-extending lower branches 221 and 222 extending from the bending part 211. In the compressed state, adjacent rods abut or cross each other through the two adjacent lower branches, so that the functional part forms a mesh structure, as shown in Figures 16, 17 and 19.

[0187] Optionally, in the uncompressed state, two adjacent lower support segments of adjacent rods abut each other at a point away from their ends, and the two lower support segments converge parallel to each other from the abutment point towards their ends. See [reference needed]. Figure 13 , 14 .

[0188] In a preferred embodiment of the vena cava filter of the present invention, the lateral branch 23 is led out from the bend 211, and first leads out as a straight section substantially parallel to the lower branch, then transitions into an arc-shaped curved section with a gradually increasing radius of curvature. The end of the arc-shaped curved section has a deflection angle greater than 180 degrees relative to its starting end, and its end points towards the central axis. The lateral branch 23 is located between the two lower branches 221 and 222, and the straight section of the lateral branch 23 is arranged along the width direction of the rod with the lower branch 22.

[0189] Under the same conditions, compared with the comparative vena cava filter that has no bends and whose lower branch directly leads to the arc-shaped bend of the lateral branch 23, the preferred vena cava filter embodiment of the present invention has superior structural mechanics, with overall reduced stress and more uniform stress distribution. See [link to documentation]. Figure 18 and Figure 19 , Figure 19 The preferred embodiment of the vena cava filter of the present invention shows a significant reduction in stress at the root of the lateral branch segment 23 (i.e., the starting end), and there is no stress concentration area at this root, compared to... Figure 18 The comparative example shown can significantly reduce the risk of the side branch 23 breaking at the root. At the same time, the lower stress is conducive to the compression and recovery of the side branch 23, avoiding forward jump or reducing recovery resistance, and greatly improving operability and safety.

[0190] • Implantable filters

[0191] One object of the present invention is to provide an implantable filter that can be constructed using at least the aforementioned implant structure, a rod constituting a functional part, or a vena cava filter. For example, the implantable filter has the aforementioned implant structure and can also be the aforementioned vena cava filter. The implantable filter has an anchoring member and a filtering member, both of which can be selected from the aforementioned rod constituting the functional part, and satisfies the following: the anchoring member and the filtering member are configured to undergo elastic deformation under compressive load in the implanted state, and satisfy that, under the same radial dimension after compression, the radial elastic force of the anchoring member is greater than the radial elastic force of the filtering member.

[0192] In general, the implantable filter provided by this invention typically includes:

[0193] A central component that can be detachably connected to a conveying device for conveying the filter within the lumen;

[0194] Multiple anchoring and filtering components are spaced apart around the central component and are limited by the central component to achieve positioning and filtration within the cavity;

[0195] The filter has both an unrestrained state and a radially compressed implanted state.

[0196] The anchoring member and the filter member are configured to undergo elastic deformation under compressive load in the implanted state, and satisfy that, under the same radial dimension after compression, the radial elastic force of the anchoring member is greater than that of the filter member.

[0197] Testing the radial elastic force of anchoring components and filter components is a conventional technique in this field. Those skilled in the art can design appropriate fixtures or carriers based on the configuration of the anchoring components and filter components, and obtain the force through force testing equipment, such as a tensile testing machine.

[0198] For example, refer to Figure 1-6The implantable structure can serve as a filter implantable within a lumen. The upper branch 21 can function as a coupling member, the lower branch 22 as a filtering member, and the side branch 23 as an anchoring member. At least one upper branch 21, one lower branch 22, and one side branch 23 constitute a group. Multiple groups of components are arranged around the central portion 1, for example... Figure 10 The arrangement can be as follows. Alternatively, it can consist of an upper support segment 21, two lower support segments 22 (i.e., 221 and 222), and a side support segment 23, forming a group of multiple groups of components arranged around the central part 1, for example... Figure 11 The arrangement. Obviously, Figure 7-9 The implantable structure can also serve as a filter that can be implanted into a lumen. Multiple sets of components are arranged around the central part 1, such as... Figure 12 As shown.

[0199] In the aforementioned implant structure, the elastic relationship between the anchoring and filtering components can typically be satisfied by selecting the specifications (e.g., thickness) or shape of each component: both the anchoring and filtering components are constructed to undergo elastic deformation under compressive loads in the implanted state, and the radial elastic force of the anchoring component is greater than that of the filtering component under the same radial dimension after compression. This selection of component specifications or shapes is a conventional technique known to those skilled in the art. For example, thicker and shorter rod components are generally less prone to deformation than thinner and longer rod components; under the same deformation, the former can have a greater elastic force. Alternatively, different rod component shapes can be selected to create differences in deformation under compressive loads, thereby obtaining different radial elastic forces. For instance, a rod component with more bending configurations in the load application direction (e.g., the filter radial direction) can be selected. Multiple bending configurations can be constructed to undergo elastic deformation in the load application direction. Compared to a straight rod without bending configurations, the former can provide greater elastic force when the radial compressive load on the rod component is reduced by the same radial length because it accumulates greater deformation.

[0200] To verify the differences in radial elastic force among the components, measurements can be taken.

[0201] For example, for Figure 1-6To measure the radial elastic force of the lower branch 22 and the side branch 23 in the implant structure, the upper branch 21 can be positioned and fixed first. The test wall with a pressure sensor is then positioned so that it always contacts the outer edge of the lower branch 22 or the side branch 23 along the radial direction of the filter (i.e., the direction perpendicular to the MM axis). The test wall advances a preset distance radially to simulate an implantation state. The lower branch 22 or the side branch 23 is compressed and undergoes elastic deformation, exhibiting radial elastic force, which can be measured by the pressure sensor. Typically, the preset distance the test wall advances radially is different for the lower branch 22 and the side branch 23, so that the lower branch 22 and the side branch 23 have essentially the same radial dimension when measuring the radial elastic force.

[0202] The test wall should have a sufficiently large area to maintain contact with the lower support section 22 or the side support section 23 during the test.

[0203] Furthermore, to measure the radial elastic force of the lower support segment 22 and the side support segment 23, it is also possible to choose not to fix the upper support segment 21, but to directly fix the center part 1, so that the test wall with the pressure sensor always abuts against the outer edge of the lower support segment 22 or the side support segment 23 along the radial direction of the filter (i.e., the direction perpendicular to the MM axis). Then, following the aforementioned method, the radial elastic force of the lower support segment 22 and the side support segment 23 in the simulated implantation state can be measured. During the test, the upper support segment 21 can deform along with the lower support segment 22 or the side support segment 23.

[0204] Similarly, Figure 7-9 The implant structure can also serve as a filter structure, similar to the aforementioned... Figure 1-6 Unlike other filters, this one lacks coupling components. The upper support segment 21 and lower support segment 22 function as a single rod-shaped filter component, while the other rod 4 (the aforementioned first array rod) serves as an anchoring component. Both extend directly from the central portion 1 and are relatively independent, not directly connected. To measure the radial elastic force of the lower support segment 22 and rod 4, the central portion 1 is first positioned and fixed. The test wall, equipped with a pressure sensor, is then positioned against the outer edge of the lower support segment 22 or rod 4 along the radial direction of the filter (i.e., the direction perpendicular to the MM axis). The test wall is then advanced a predetermined distance radially to simulate an implantation state. The lower support segment 22 or rod 4 is compressed, undergoing elastic deformation and exhibiting radial elastic force, which can be measured by the pressure sensor.

[0205] In the above filter structure, the filter components and anchoring components are arranged in layers, but they can also be arranged in a non-layered manner. Layered arrangement means that multiple filter components are arranged in a ring-shaped central component at different positions along the filter axis, while multiple anchoring components are arranged in another ring-shaped central component at different positions along the filter axis.

[0206] In the preferred filter structure, along the filter axis, the anchoring member is closer to the central component, as referenced. Figure 1-9 The control force on the central component can be transmitted to the anchoring component more effectively, thus improving the accuracy of control.

[0207] The layered filter components and anchoring components constitute the filter section and anchoring section, respectively, and these components can have different diameters. (Reference) Figure 10-12 The outer rings of multiple filter components form the third outer perimeter 33 of the filter, and its diameter is the diameter of the filter section. The outer rings of multiple anchoring components form the second outer perimeter 32 of the filter, and its diameter is the diameter of the anchoring section. (Refer to...) Figure 1-9 The third outer periphery 33 and the second outer periphery 32 are at different distances from the center part 1 along the filter axis (MM axis), that is, the diameters of the filter part and the anchoring part are different.

[0208] The main difference between the two types of filter structures mentioned above lies in the coupling components. The coupling components should have elastic deformation capabilities so that the anchoring components and filtering components in each group can be linked together, and all coupling components are gathered and fixed at one end to the central component.

[0209] The linkage between the anchoring and filtering components within each group can refer to:

[0210] The elastic deformation of the anchoring components within each group actuates the filtering and coupling components;

[0211] Or / and, the elastic deformation of the filter structure within each group actuates the anchoring and coupling components.

[0212] refer to Figure 1-19 The central part 1 in the diagram corresponds to the central component of the aforementioned filter. In contrast to the coupling member formed by the upper support 21, the central part 1 is a hub, which is basically rigid. (See reference...) Figure 7-9 The upper support segment 21 and the lower support segment 22 together form a single rod-shaped filter component. The elastic deformation occurring under compression or tension does not cause displacement or shape change in the other rod 4. The deformation stress of the upper support segment 21 or the lower support segment 22 is transferred to the central component, but essentially cannot be transferred to the rod 4. (See also...) Figure 1-6 As shown in Figures 13-19, the anchoring member formed by the side support 23 undergoes elastic deformation under compression or tension, and the deformation stress is transmitted to the upper support 21. The upper support 21 undergoes corresponding elastic deformation, which in turn causes the lower support (22, 221 or 222) to change position or shape.

[0213] Preferably, the anchoring member or filter member is actuated at least in the radial direction of the filter, which is very advantageous for adjusting the shape, position or orientation of the anchoring member or filter member in the implanted state.

[0214] The anchoring component and the filtering component form an actuation relationship, further enhancing the ability to indirectly control and adjust the filtering component. This means that by manipulating the position or attitude change of the anchoring component, it is possible to effectively adjust the position and attitude of the filtering component simultaneously, while changes in the position or attitude of the filtering component will have little or no adjustment to the position and attitude of the filtering component.

[0215] by Figure 13-15 Taking the filter shown as an example, the filter can be implanted in a lumen (e.g., the inferior vena cava). The filter shown has a double-layer support. The anchoring component (i.e., the lateral branch 23) provides a greater radial support force and plays the main anchoring function, positioning and holding the filter within the implanted vena cava. At the same time, since the filtering components (i.e., the lower branches 221 and 222) provide a smaller radial support force, their posture and orientation within the implanted vena cava are constrained by the first layer of rods. Therefore, this filter has the following characteristics: as long as the anchoring part composed of six anchoring components is positioned in the center of the venous lumen, the second layer of rods, which mainly performs the filtering function, can also be positioned in the center of the venous lumen, effectively avoiding the phenomenon that the thrombus cannot be intercepted due to the offset of the filtering components, thus ensuring the filtering effect.

[0216] This design is more beneficial in certain specific scenarios. For example, when the filter is released at an angle in the vein, the tilting of the filter in the vein is unavoidable. When the filter is implanted into the inferior vena cava via the jugular vein, the filter component is released into the delivery sheath before the anchoring component. The filter component adheres to the inner wall of the blood vessel and plays an auxiliary anchoring role. The anchoring component, which is released later, has a greater radial elastic force, which can overcome the directional effect of the filter component's anchoring on the filter. Therefore, it helps to make the retrieval hook side of the filter released later tend towards the center of the vein lumen, reducing the tilt angle of the filter. The anchoring component has the performance of "correcting deviation" and redirecting the filter.

[0217] The aforementioned effect relies particularly on the phase-actuated design of the anchoring and filtering components. For example, in the filter shown, both the anchoring and filtering components are separated by a coupling component, which significantly improves the ability of the filtering component to be constrained by the anchoring component.

[0218] The staggered arrangement of the two components in the circumferential direction is also a means to improve the above effect. This reduces the tension between the anchoring and filtering components distributed on opposite sides, which helps to release the anchoring and filtering components and improves the effect of the redirection filter.

[0219] Furthermore, the anchoring components, combined with the load-bearing structure, provide the filter with improved operability and redirection capabilities. For example, regardless of whether release is via the femoral vein or jugular vein, tilting the filter may result in incomplete release of some anchoring components; see [link to relevant documentation]. Figure 20bAt least one anchoring member has a significantly different contact position with the vein wall compared to the others. This may be because, during filter release, the orifice of the delivery sheath carrying the filter is off-center from the vein, causing the aforementioned anchoring members to be too close to the vein wall and unable to release fully. Therefore, the filter is susceptible to tilting under varying loads. The U-shaped load-bearing structure of the anchoring member provides radial elasticity, thus providing power and space for deformation of the anchoring or filtering member along the venous axis by dragging or pulling the delivery cable connecting the filter (depending on the pathway), which may facilitate the complete release of the anchoring or filtering member. See [link to relevant documentation]. Figure 20c This achieves the functions of "correction" and redirection filters as mentioned above.

[0220] The filter shown in the diagram has no anchors or sharp designs, and does not cause damage to the inner wall of the vein. Therefore, the twisting, vibration, and migration of the filter in the vein will not cause damage to the vein, which is very beneficial for the aforementioned "correction" and redirection operations.

[0221] Load buffer structures can typically have a bending configuration in the load direction, enabling them to undergo elastic deformation, for example... Figure 1-4 The side branch segment 23 configuration shown in 6, 13 or 15 or Figure 7 , 9 The rod has a configuration of 4.

[0222] In a preferred embodiment, the load-bearing structure of the side support 23 is generally U-shaped, as described above. Figure 13 As shown in 15.

[0223] A better design, still referencing Figure 13 , 15 Anchoring members with load buffering structures can withstand greater compressive loads and reduce strain at the root of coupling members.

[0224] Test Results

[0225] right Figure 13 The filter shown refers to the aforementioned filter. Figure 1-6 A method for measuring the radial elastic force of the inferior branch 22 and the lateral branch 23 of the implant structure was used to measure the radial elastic force of the inferior branch (221 or 222) and the lateral branch 23 when the implant was placed in a simulated inferior vena cava. The test results for two sizes (1822, 2226) of filters under compression to the target diameter are given below.

[0226] When the 1822 specification filter is not restrained, the diameter of the anchoring part is 18 mm and the diameter of the filter part is 22 mm.

[0227] When the 2226 specification filter is not restrained, the diameter of the anchoring part is 22 mm and the diameter of the filter part is 26 mm.

[0228]

[0229]

[0230] It should be understood that the radially compressed implantation state of the filter described in this patent can refer to the compressed state of the filter simulating insertion into the lumen of a real physiological and anatomical structure, such as the state in which a compressive load is applied to the filter by an expansion and compression device such as a tension machine or a gripping machine.

[0231] The present invention has been described in detail above. Specific examples have been used to illustrate the implementation of the present invention. The above description of the embodiments is only for the purpose of helping to understand the present invention. It should be noted that those skilled in the art can make several improvements to the present invention without departing from the principle of the present invention, and these improvements also fall within the protection scope of the claims of the present invention.

Claims

1. An implantable filter, characterized in that, include: A central component, detachably connected to a conveying device for transporting the filter within a lumen; a plurality of anchoring members and a plurality of filtering members, spaced apart and constrained by the central component, for positioning and filtration within the lumen; the filter has an unrestrained state and an implanted state under radial compression, wherein the anchoring members and the filtering members are configured to elastically deform under compressive load in the implanted state, and satisfying that, under the same radial dimension after compression, the radial elastic force of the anchoring members is greater than that of the filtering members; the plurality of anchoring members and the plurality of filtering members The components are arranged in layers along the axial direction of the filter, wherein the plurality of anchoring components are arranged in one layer to form an anchoring portion with an outer diameter, and the plurality of filtering components are arranged in another layer to form a filtering portion with an outer diameter; along the axial direction, the anchoring portion is closer to the central component than the filtering portion; the plurality of anchoring components and the plurality of filtering components are arranged in corresponding groups, and the anchoring components and filtering components in each group are connected by a coupling component, and the anchoring components and filtering components in each group can actuate each other through the coupling component; the coupling component in each group can be actuated by the anchoring components and / or the filtering components to undergo elastic deformation.

2. The filter according to claim 1, characterized in that: When the filter is in an unrestrained state, the outer diameter of the anchoring part is smaller than the outer diameter of the filter part.

3. The filter according to claim 1, characterized in that: The central component has a connecting part at one end along the filter axis for connecting to the conveying device; the other end of the central component has a recovery part that can be captured by a recovery device, which is used to remove the implanted filter within the lumen.

4. The filter according to claim 3, characterized in that: Along the filter axis, the anchoring part and the filtering part are located on the connecting part side of the central component.

5. The filter according to claim 3, characterized in that: The central component is a hub, and the connecting part of the central component is a thread provided on the inner circumference of the hub, which can be threadedly connected to the conveying device; the recovery part of the central component is a hook-shaped body formed by slotting the hub or a hook-shaped body attached to the hub, which can be captured by a recovery device with a collar.

6. The filter according to claim 1, characterized in that: The anchoring member has a deformable load-bearing structure with a curved configuration for buffering compressive loads.

7. The filter according to claim 6, characterized in that: The elastic deformation of the anchoring member within each group actuates the filter member and the coupling member; or / and the elastic deformation of the filter member within each group actuates the anchoring member and the coupling member.

8. The filter according to claim 7, characterized in that: The anchoring member or filtering member is actuated at least in the radial direction of the filter.

9. The filter according to claim 6, characterized in that: Along the circumferential direction of the filter, the anchoring components and filtering components within the assembly are arranged in a staggered manner.

10. The filter according to claim 6, characterized in that: The anchoring member, the filtering member, and the coupling member are all rod-shaped members; wherein, the coupling member is led out from the central member and extends away from the central member to its end, and each coupling member's end leads out an anchoring member and two filtering members extending outward from the coupling member, and the led-out anchoring member is located between the two filtering members.

11. The filter according to claim 10, characterized in that: The coupling member has a bend near its end, and the angle between the coupling member and the axial centerline of the central component decreases in the direction of its end after passing through the bend; the filter member extends downward along the filter axial direction towards the bend, and two adjacent filter members led out from two adjacent coupling members extend towards each other and form a movable contact.

12. The filter according to claim 11, characterized in that: The anchoring member is basically coplanar with the coupling member from which it is derived, and the anchoring member extends to its tail section in a generally U-shaped or V-shaped curved configuration, forming a load buffer structure.

13. The filter according to claim 12, characterized in that: The tail section of the anchoring member is located above the bend along the filter axis and tends toward the central component.

14. The filter according to claim 10, characterized in that: The width of the anchoring member and the filter member is smaller than the width of the coupling member, and the length of the anchoring member is smaller than the length of the filter member but larger than the length of the coupling member.

15. The filter according to claim 1, characterized in that: Both the anchoring component and the filtering component are non-invasive structures that do not penetrate the inner wall of the cavity.

16. The filter according to claim 1, characterized in that: The filter is a thrombus filter that can be implanted in the inferior vena cava.

17. The filter according to any one of claims 1-16, characterized in that: The anchoring member and the filtering member are configured to have different radial compression ratios for the same radial dimension after compression; wherein, when the radial dimension after compression is 18-32 mm, the anchoring member has a radial compression ratio of less than 30%, and the filtering member has a radial compression ratio of greater than 50%, and at this time the radial elastic force of the anchoring member is 2-8 times the radial elastic force of the filtering member; wherein, the radial compression ratio refers to the ratio of the difference in radial length before and after compression to the radial length before compression.

18. The filter according to claim 17, characterized in that: The anchoring component has a radial elastic force of 0.2-0.8 N, and the filter component has a radial elastic force of 0.05-0.2 N.

19. An implantable filter, characterized in that, include: A central component, detachably connected to a conveying device for conveying the filter within a cavity; a plurality of anchoring members and a plurality of filtering members, spaced apart and limited by the central component, for positioning and filtration within the cavity; the plurality of anchoring members and the plurality of filtering members are arranged in layers along the axial direction of the filter, wherein the plurality of anchoring members are arranged in one layer to form an anchoring portion with an outer diameter, and the plurality of filtering members are arranged in another layer to form a filtering portion with an outer diameter; the radial support force of the anchoring portion is greater than the radial support force of the filtering portion; along the axial direction, the anchoring portion is closer to the central component than the filtering portion; the plurality of anchoring members and the plurality of filtering members are arranged in corresponding groups, and the anchoring members and filtering members in each group are connected by a coupling member, and the anchoring members and filtering members in each group can actuate each other through the coupling member; the coupling member in each group can be actuated by the anchoring members and / or the filtering members to undergo elastic deformation.

20. The filter according to claim 19, characterized in that: The number of anchoring members constituting the anchoring part is not greater than the number of filtering members constituting the filtering part; wherein the anchoring members and the filtering members are configured to undergo elastic deformation under compressive load when implanted, and satisfy that under the same radial dimension after compression, the radial elastic force of the anchoring member is greater than the radial elastic force of the filtering member.

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