A filter

Abstract

This invention provides a filter comprising multiple first filter rods and multiple second filter rods. The first filter rods are arranged around the axis of the filter, and the second filter rods are also arranged around the axis of the filter. The proximal ends of all the first and second filter rods are converged and interconnected. The first filter rods are located outside the proximal ends of the second filter rods, and the thickness of the first filter rod is less than the thickness of the second filter rod. This filter, while ensuring implantation stability, also rationally adjusts its radial support force through differentiated filter rod thickness design, thereby reducing stimulation to the target lumen, reducing endothelial hyperplasia, and thus reducing the encapsulation of the filter by the vascular endothelium, which is beneficial for extending the retrieval time window.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and more specifically to a filter. Background Technology

[0002] Venous thromboembolism (VTE) is a common clinical condition with a high incidence and mortality rate. VTE includes deep vein thrombosis (DVT) and pulmonary embolism (PE). DVT commonly occurs in the veins of the lower extremities, while PE is mainly caused by thrombi forming in the venous system or right heart and then detaching into the pulmonary artery. It is a major cause of disease and death.

[0003] Anticoagulation therapy has always been the gold standard for VTE treatment, aiming to prevent thrombus formation, prevent pulmonary embolism (PE), and restore patency of the embolized vein. When patients have contraindications to anticoagulation or develop blood complications that necessitate discontinuation of anticoagulation, a vena cava filter (VCF) can be implanted in the inferior vena cava to intercept detached thrombi and prevent fatal PE. However, current filters, after implantation in the inferior vena cava, often cause excessive vascular stimulation due to the excessive support provided by the filter, leading to endothelial cell proliferation and encapsulation of the filter, which hinders subsequent filter retrieval. Summary of the Invention

[0004] The purpose of this invention is to provide a filter that improves the filter's support performance and reduces irritation to blood vessels.

[0005] To achieve the above objectives, the present invention provides a filter comprising a plurality of first filter rods and a plurality of second filter rods, wherein the plurality of first filter rods are arranged around the axis of the filter, and the plurality of second filter rods are arranged around the axis of the filter, and the proximal ends of all the first filter rods and all the second filter rods are converged and interconnected; the first filter rods are located outside the proximal ends of the second filter rods, and the thickness of the first filter rods is less than the thickness of the second filter rods.

[0006] Optionally, the thickness of the first filter rod is 0.25mm to 0.35mm, and the thickness of the second filter rod is 0.3mm to 0.4mm.

[0007] Optionally, the surface of the second filter rod is smooth and includes a first segment and a second segment. The first segment is partially located inside the first filter rod, and the distance from the first segment to the axis of the filter first increases and then decreases along the direction from the proximal end to the distal end. The second segment is connected to the distal end of the first segment, and the distance from the second segment to the axis of the filter gradually increases along the direction from the proximal end to the distal end.

[0008] Optionally, the distal end of the first filter rod is located on the proximal side of the intersection of the first segment and the second segment of the second filter rod, and the distance H4 from the distal end of the first filter rod to the intersection of the first segment and the second segment of the second filter rod in the axial direction of the filter is 1mm to 3mm.

[0009] Optionally, the second filter rod is in a straight configuration, and the distance from the second filter rod to the axis of the filter gradually increases from the proximal end to the distal end.

[0010] Optionally, the surface of the first filter rod is smooth, and the distance from the first filter rod to the axis of the filter first increases and then decreases along the direction from the proximal end to the distal end; or, the distance from the first filter rod to the axis of the filter first increases and then remains constant along the direction from the proximal end to the distal end.

[0011] Optionally, the first filter rod includes at least a first arc segment and a second arc segment, the convex side of the first arc segment is arranged toward the interior of the filter, the second arc segment is located at the distal end of the first arc segment, and the concave side of the second arc segment is arranged toward the interior of the filter.

[0012] Optionally, the filter further includes an anchoring portion connected to the distal end of the second filter rod, and includes an anchoring element and a puncture-resistant structure. The anchoring element is used to penetrate the wall of the target cavity, and the puncture-resistant structure is used to limit the penetration depth of the anchoring element.

[0013] Optionally, the puncture-resistant structure is at least partially linear and connected to the distal end of the second filter rod, and the angle θ3 formed by the puncture-resistant structure and the axis of the filter is 4° to 10°.

[0014] The anchoring components include a first anchoring component and a second anchoring component; the first anchoring component is a barb and is connected to the junction of the anti-puncture structure and the second filter rod, with the free end of the barb facing the proximal end of the filter; a V-shaped structure is formed between the first anchoring component and the second filter rod, the sharp corner of the V-shaped structure is rounded, the fourth radius R4 of the rounded corner is 0.4mm to 0.6mm, and the opening angle θ4 of the V-shaped structure is 65° to 85°, the length L1 of the line connecting the free end and the fixed end of the first anchoring component is 0.8mm to 1.6mm; the second anchoring component has a straight line configuration, with the free end of the second anchoring component facing the distal end of the filter, the fourth acute angle θ5 formed by the second anchoring component and the anti-puncture structure is 30° to 50°, and the length L2 of the second anchoring component is 1mm to 1.5mm.

[0015] To achieve the above objectives, the present invention also provides a filter, comprising a plurality of first filter rods and a plurality of second filter rods, wherein the plurality of first filter rods are arranged around the axis of the filter, and the plurality of second filter rods are arranged around the axis of the filter, and the proximal ends of all the first filter rods and all the second filter rods are converged and interconnected; the surface of the first filter rods is smooth, and the distance from the first filter rod to the axis of the filter first increases and then decreases along the direction from the proximal end to the distal end.

[0016] Optionally, the surface of the second filter rod is smooth and includes a first segment and a second segment. The first segment is partially located inside the first filter rod. The distance from the first segment to the axis of the filter first increases and then decreases in the direction from the proximal end to the distal end. The second segment is connected to the distal end of the first segment. The distance from the second segment to the axis of the filter gradually increases in the direction from the proximal end to the distal end.

[0017] Optionally, the first filter rod includes a first arc segment, a first straight segment, a second arc segment, a third arc segment, and a second straight segment that are smoothly connected sequentially from the proximal end to the distal end; the convex sides of the first arc segment and the third arc segment are arranged towards the interior of the filter, and the concave side of the second arc segment is arranged towards the interior of the filter; the distance from the first straight segment to the axis of the filter gradually increases from the proximal end to the distal end, and the distance from the second straight segment to the axis of the filter gradually decreases from the proximal end to the distal end.

[0018] Optionally, the radius R1 of the first arc segment is 8mm to 10mm, the radius R2 of the second arc segment is 4mm to 6mm, and the radius R3 of the third arc segment is 5mm to 8mm; the angle θ1 formed by the first straight segment and the axis of the filter is 55° to 75°, and the angle θ2 formed by the second straight segment and the axis of the filter is 8° to 12°.

[0019] Optionally, the first filter rod has a widest point, which is the point where the distance from the first filter rod to the axis of the filter is the greatest; in the axial direction of the filter, the distance H1 between the widest point and the proximal end of the first filter rod is 6mm to 10mm, and the widest points of multiple first filter rods are located on a first circle with a diameter D1 of 28mm to 30mm; the axial distance H2 between the distal end of the first filter rod and the proximal end of the first filter rod is 16mm to 24mm, and the distal ends of multiple first filter rods are located on a second circle with a diameter D2 of 22mm to 24mm.

[0020] Optionally, the distal end of the first filter rod is located on the proximal side of the intersection of the first segment and the second segment of the second filter rod, and the distance H4 from the distal end of the first filter rod to the intersection of the first segment and the second segment of the second filter rod in the axial direction of the filter is 1mm to 3mm.

[0021] Compared with the prior art, the filter of the present invention has the following advantages:

[0022] The aforementioned filter includes multiple first filter rods and multiple second filter rods. The multiple first filter rods are arranged around the axis of the filter, and the multiple second filter rods are arranged around the axis of the filter. The proximal ends of all the first filter rods and all the second filter rods converge and connect to each other. The first filter rods are located outside the proximal ends of the second filter rods, and the thickness of the first filter rods is less than the thickness of the second filter rods. By differentiating the thicknesses of the first and second filter rods, after the filter is implanted into the target lumen, the first filter rods can provide less support force, while the second filter rods can provide greater support force. While ensuring the stability of the filter, the stimulation to the target lumen is minimized, thereby reducing endothelial cell proliferation, reducing the vascular endothelium's coverage of the filter, and improving the filter's recovery time window.

[0023] The aforementioned filter includes multiple first filter rods and multiple second filter rods. The multiple first filter rods are arranged around the axis of the filter, and the multiple second filter rods are arranged around the axis of the filter. The proximal ends of all the first filter rods and all the second filter rods are converged and interconnected. The surfaces of the first filter rods are smooth, and the distance from the first filter rod to the axis of the filter first increases and then decreases along the direction from the proximal end to the distal end. This allows the first filter rod to contact the target lumen line with a contact area as small as possible, maintaining the filter in a centered position within the target lumen. It also reduces the supporting force to minimize stimulation of the target lumen, thereby reducing the encapsulation of the filter caused by endothelial hyperplasia of the target lumen and extending the filter's recovery time window.

[0024] Furthermore, the surface of the second filter rod is smooth and includes a first segment and a second segment. The first segment is partially located inside the first filter rod, and the distance from the first segment to the axis of the filter first increases and then decreases in the direction from the proximal end to the distal end. The second segment is connected to the distal end of the first segment, and the distance from the second segment to the axis of the filter gradually increases in the direction from the proximal end to the distal end. Thus, near the intersection of the first segment and the second segment of the second filter rod, the density of the filter rod is relatively high, which is beneficial for intercepting small plugs. Attached Figure Description

[0025] The accompanying drawings are provided to better understand the invention and are not intended to unduly limit the scope of the invention. Wherein:

[0026] Figure 1 This is a schematic diagram of the filter provided in Embodiment 1 of the present invention;

[0027] Figure 2 This is a partial structural diagram of the filter provided according to Embodiment 1 of the present invention, mainly showing the recovery hook and the first filter rod;

[0028] Figure 3 This is a partial structural diagram of the filter provided according to Embodiment 1 of the present invention, in which the relevant dimensions of the first filter rod are mainly marked;

[0029] Figure 4 This is a partial structural schematic diagram of the filter provided in Embodiment 1 of the present invention. The figure mainly marks the acute angles formed by the first straight line segment and the second straight line segment of the first filter rod with the axis of the filter.

[0030] Figure 5 This is a partial structural schematic diagram of the filter provided according to Embodiment 1 of the present invention. The figure mainly shows the second filter rod and its distal anchoring part.

[0031] Figure 6 This is a partial structural schematic diagram of the filter provided according to Embodiment 1 of the present invention, mainly showing the anchoring part and its related dimensions;

[0032] Figure 7 This is a top view of the filter provided according to Embodiment 1 of the present invention;

[0033] Figure 8 This is a schematic diagram of the filter provided according to Embodiment 1 of the present invention, mainly showing the relevant dimensions of the second filter rod;

[0034] Figure 9 This is a schematic diagram of the filter provided in Embodiment 2 of the present invention;

[0035] Figure 10 This is a schematic diagram of the filter provided in Embodiment 3 of the present invention;

[0036] Figure 11 This is a schematic diagram of the filter provided in Embodiment 4 of the present invention;

[0037] Figure 12 This is a schematic diagram of the filter provided in Embodiment 5 of the present invention;

[0038] Figure 13 This is a schematic diagram of the filter provided according to Embodiment Six of the present invention.

[0039] [The annotations in the attached figures are explained below]:

[0040] 100 - Filter; 110 - First filter rod 110; 111 - First arc segment; 112 - First straight segment; 113 - Second arc segment; 114 - Third arc segment; 115 - Second straight segment; 116 - Third straight segment; 117 - Fourth straight segment; 120 - Second filter rod; 130 - Retrieval hook; 101 - First connecting ring; 102 - Second connecting ring; 121 - First segment; 122 - Second segment; 140 - Anchoring part; 140a - First anchoring part; 140b - Second anchoring part; 141 - First anchoring element; 142 - Second anchoring element; 143 - Puncture-resistant structure. Detailed Implementation

[0041] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show components related to the present invention and are not drawn according to the actual number, shape, and size of components in the actual implementation. In the actual implementation, the type, quantity, and proportion of each component can be arbitrarily changed, and the component layout may also be more complex.

[0042] Furthermore, while each embodiment described below possesses one or more technical features, this does not imply that users of the present invention must simultaneously implement all technical features in any embodiment, or can only separately implement some or all technical features in different embodiments. In other words, provided it is feasible, those skilled in the art can, based on the disclosure of the present invention and depending on design specifications or implementation requirements, selectively implement some or all technical features in any embodiment, or selectively implement a combination of some or all technical features in multiple embodiments, thereby increasing the flexibility in implementing the present invention.

[0043] As used herein, the singular forms “a,” “an,” and “the” include plural objects, and the plural form “a plurality” includes two or more objects, unless otherwise expressly indicated. As used herein, the term “or” is generally used to include the meaning of “and / or,” unless otherwise expressly indicated, and the terms “install,” “connect,” and “link” should be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection. Connections can be mechanical or electrical. Connections can be direct or indirect through an intermediate medium, and can represent internal communication between two elements or an interaction between two elements. Those skilled in the art will understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0044] In this article, the terms "proximal" and "distal" refer to the relative orientation, position, and direction of the components or actions of the medical device relative to the heart during normal use. Although "proximal" and "distal" are not restrictive, "proximal" usually refers to the end of the medical device that is closer to the heart during normal use, while "distal" usually refers to the end that is farther away from the heart.

[0045] To make the objectives, advantages, and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clearly illustrate the objectives of the embodiments of the present invention. The same or similar reference numerals in the drawings represent the same or similar parts.

[0046] <Example 1>

[0047] Figure 1 A schematic diagram of the filter 100 provided in this embodiment is shown. Figure 1 As shown, the filter 100 includes multiple first filter rods 110 and multiple second filter rods 120. The multiple first filter rods 110 are arranged around the axis of the filter 100, and the multiple second filter rods 120 are arranged around the axis of the filter 100. The proximal ends of all the first filter rods 110 and all the second filter rods 120 are converged and interconnected. The first filter rods 110 are located outside the proximal ends of the second filter rods 120, and the thickness of the first filter rods 110 is less than the thickness of the second filter rods 120.

[0048] The filter 100 is implanted into a target lumen to intercept emboli, such as the vena cava. A portion of the first filter rod 110 contacts the wall of the vena cava, and the distal end of the second filter rod 120 can make point contact with the vena cava wall. Generally, the greater the thickness of the filter rod, the greater the radial support force it provides to the vena cava, and the greater the stimulation to the vena cava. Therefore, this embodiment differentiates the thicknesses of the first filter rod 110 and the second filter rod 120 to minimize stimulation to the vena cava while ensuring the stability of the filter 100 after implantation, thereby reducing endothelial cell proliferation and the encapsulation of the filter 100 by the proliferating vascular endothelium, which helps to extend the retrieval time window of the filter 100. Preferably, the thickness of the first filter rod 110 can be 0.25 mm to 0.35 mm, and the thickness of the second filter rod 120 can be 0.3 mm to 0.4 mm.

[0049] Those skilled in the art will understand that the filter 100 further includes a retrieval hook 130, which is connected to the proximal ends of the first filter rod 110 and the second filter rod 120. Preferably, the retrieval hook 130 is bent toward the axis of the filter 100, so that the axis of the filter 100 passes through the retrieval hook 130. Additionally, a contrast-enhancing element (not shown in the figure) may be provided on the retrieval hook 130 to facilitate determining the position of the retrieval hook 130 within the vena cava. The contrast-enhancing element can be manufactured using any suitable contrast-enhancing material such as tantalum, platinum-iridium alloy, or platinum-tungsten alloy. Furthermore, the number of the first filter rods 110 can be 3 to 12, and preferably all the first filter rods 110 are evenly arranged around the axis of the filter 100. Similarly, the number of the second filter rods 120 can be 3 to 12, and preferably all the second filter rods 120 are evenly arranged around the axis of the filter 100. This ensures that the filter 100 has a uniform supporting force in the circumferential direction, allowing it to remain centered within the vena cava and preventing tilting that would cause the retrieval hook 130 to adhere to the wall (i.e., the retrieval hook 130 to rest against the vena cava). This facilitates the snare of the catcher encircling the retrieval hook 130 when retrieving the filter 100. Here, "centered" means that the axis of the filter 100 is substantially coincident with the axis of the vena cava.

[0050] Preferably, the first filter rod 110 can be obtained by cutting and shaping a first tube with a wall thickness of 0.25mm to 0.35mm, and the second filter rod 120 can be obtained by cutting and shaping a second tube with a wall thickness of 0.3mm to 0.4mm, with the first and second tubes nested together. This allows for the convenient acquisition of first filter rods 110 and second filter rods 120 of different thicknesses. Furthermore, by cutting the first filter rod 110 and second filter rod 120 from two separate tubes, more options are available for the width of the first filter rod 110 and second filter rod 120, thus enabling more flexible adjustment of the radial support force of the filter 100. Here, the width of the first filter rod 110 can be smaller than the width of the second filter rod 120; more specifically, the width of the first filter rod 110 can be 0.3mm to 0.6mm, and the width of the second filter rod 120 can be 0.4mm to 0.8mm. It can be understood that the nesting arrangement of the first tube and the second tube means that the first tube is located outside the second tube, or the second tube is located outside the first tube.

[0051] The recycling hook 130 can be obtained by cutting and shaping the first tube alone, or by cutting and shaping the second tube alone, or by cutting and shaping both the first and second tubes simultaneously. The recycling hook 130 is formed by cutting at least one tube, eliminating the need for additional connection between it and the first filter rod 110 and / or the second filter rod 120, thus ensuring greater stability and reliability. Figure 2 As shown, the forming method of the filter 100 is illustrated by taking the example of the retrieval hook 130 being obtained solely by cutting and shaping the first tube body, and the first tube body being positioned outside the second tube body: The first tube body includes a first proximal end, a middle part, and a second distal end connected in sequence, wherein the first proximal end is cut and shaped to form the retrieval hook 130. The middle part is not cut and is retained as a circular structure to serve as a first connecting ring 101. The first distal end is cut and shaped to form multiple first filter rods 110, such that the proximal ends of these multiple first filter rods 110 are all gathered together and connected to the first connecting ring 101. Figure 5As shown, the second tube includes a second proximal end and a second distal end connected in sequence. The second proximal end is not cut and remains in a circular structure to serve as a second connecting ring 102. The second distal end is cut and shaped to obtain multiple second filter rods 120, meaning that the proximal ends of all the second filter rods 120 are gathered and connected to the second connecting ring 102. Furthermore, the outer diameter of the second tube matches the inner diameter of the first tube. Therefore, the second connecting ring is inserted into the first connecting ring, and the second connecting ring 101 is connected to the first connecting ring 102 by any suitable method, such as welding or mechanical connection. Thus, the proximal ends of the first filter rod 110 and the second filter rod 120 are connected by the first connecting ring 101 and the second connecting ring 102. Of course, in other embodiments, the first tube can be pre-fitted onto the second tube, and then cut and shaped to obtain the recovery hook 130, the first filter rod 110, and the second filter rod 120.

[0052] Please continue to refer to this. Figure 1 and combined Figures 2 to 4 In this embodiment, the surface of the first filter rod 110 is smooth, and the distance from the first filter rod 110 to the axis of the filter 100 first increases and then decreases along the direction from the proximal end to the distal end, so that multiple first filter rods 110 together constitute a structure similar to... Figure 2 and Figure 3 The crown structure shown. This structure not only improves the stability of the filter 100 within the vena cava and prevents tilting, but also facilitates the removal of the first filter rod 110 from the vena cava when the filter 100 is retracted.

[0053] For details, please refer to the following: Figure 3 and Figure 4 The first filter rod 110 includes a first arc segment 111, a first straight segment 112, a second arc segment 113, a third arc segment 114, and a second straight segment 115, which are smoothly connected sequentially from proximal to distal end. The convex sides of the first arc segment 111 and the third arc segment 114 face inwards towards the interior of the filter 100, while the concave side of the second arc segment 113 faces inwards towards the interior of the filter 100. The distance from the first straight segment 112 to the axis of the filter 100 gradually increases from proximal to distal end, while the distance from the second straight segment 115 to the axis of the filter 100 gradually decreases from proximal to distal end. In actual use, the second arc segment 113 is used to contact the wall of the vena cava. This minimizes the contact area between the first filter rod 110 and the vena cava, thereby reducing stimulation of the vena cava and reducing endothelial cell proliferation.

[0054] Optionally, in its natural state, the radius R1 of the first arc segment 111 is 8mm to 10mm, the radius R2 of the second arc segment 113 is 4mm to 6mm, and the radius R3 of the third arc segment 114 is 5mm to 8mm. The angle θ1 formed by the first straight segment 112 and the axis of the filter 100 is 55° to 75°, and the angle θ2 formed by the second straight segment 115 and the axis of the filter 100 is 8° to 12°. Furthermore, the first filter rod 110 has a widest point M, which refers to the point on the second arc segment 113 where the distance to the axis of the filter 100 is the greatest. Along the axial direction of the filter 100, the distance H1 between the widest point M and the proximal end of the first filter rod 110 is 6mm to 10mm, and the widest points M of multiple first filter rods 110 are located on a first circle with a diameter D1 of 28mm to 30mm. The axial distance H2 between the distal end and the proximal end of the first filter rod 110 is 16mm to 24mm, and the distal ends of multiple first filter rods 110 are located on a second circle with a diameter D2 of 22mm to 24mm. Through reasonable dimensional design, after the filter 100 is implanted into the vena cava, the second arc segment 113 can contact the vena cava wall line under the compression of the vena cava wall, which is beneficial to maintain good support with a small thickness, so that the filter 100 remains in a centered state. The "natural state" refers to the state when the filter 100 is naturally expanded and not implanted into the vena cava. The dimensions of the components mentioned herein generally refer to the dimensions of the corresponding components in the filter 100 in its natural state, unless otherwise specified. Furthermore, in the axial direction of the filter 100, the distance H3 from the proximal end of the recovery hook 130 to the proximal end point of the first filter rod 110 is 6 mm to 8 mm.

[0055] Please refer to this again. Figure 5 The second filter rod 120 has a smooth surface and includes a first segment 121 and a second segment 122. The first segment 121 is partially located inside the first filter rod 110, and the distance from the first segment 121 to the axis of the filter 100 increases and then decreases along the proximal-to-distal direction. The second segment 122 is connected to the distal end of the first segment 121, and the distance from the second segment 122 to the axis of the filter 100 gradually increases along the proximal-to-distal direction. Thus, a waist is formed in the second filter rod 120 at the intersection of the first segment 121 and the second segment 122, recessed towards the axis of the filter 100. Near the proximal end of the waist, the filter rod density of the filter 100 is relatively high, which can effectively intercept small plugs.

[0056] Specifically, the distal end of the first filter rod 110 is located proximally at the intersection of the first segment 121 and the second segment 122 of the second filter rod 120. Preferably, in the axial direction of the filter 100, the distance H4 between the distal end of the first filter rod 110 and the intersection of the first segment 121 and the second segment 122 of the second filter rod 120 is 1 mm to 3 mm. Typically, when the filter 100 is implanted into and dilated in the vena cava, it is subjected to radial compression from the vena cava. Compared to its natural state, the first filter rod 10 is closer to the axis of the filter 100 at this time, therefore the distal end of the first filter rod 110 is also closer axially to the intersection of the first segment 121 and the second segment 122. Generally, in the vena cava, the axial distance from the distal end of the first filter rod 110 to the intersection of the first segment 121 and the second segment 122 is 1 mm to 2 mm. Thus, on the plane where the distal end of the first filter rod 110 is located, the distance between the multiple first filter rods 110 is relatively close, and the distance between the multiple second filter rods 120 is also relatively close. This results in a higher density of filter rods in the filter 100 at that location, which also provides a better interception effect for smaller plugs.

[0057] For further information, please refer back to the reference section. Figure 1 and combined Figure 5 and Figure 6 The filter 100 further includes an anchoring portion 140, which is disposed at the distal end of the second filter rod 120. The anchoring portion 140 includes at least one anchoring element, which, under the radial support force generated by the second filter rod 120, penetrates the vena cava, allowing the distal end of the second filter rod 120 to make point contact with the vena cava wall. The second filter rod 120 has a relatively large thickness, preferably 0.3mm to 0.4mm, precisely to provide sufficient radial support force for the anchoring element to penetrate the vena cava. If the thickness of the second filter rod 120 is small, it will be correspondingly softer, resulting in insufficient radial support force, making it difficult for the anchoring element to penetrate the vena cava, and thus preventing stable contact between the distal end of the second filter rod 120 and the vena cava wall. The anchoring portion 140 can also be obtained by cutting the second tube body.

[0058] Please refer to this carefully. Figure 6In this embodiment, each anchoring portion 140 includes two anchoring elements, namely a first anchoring element 141 and a second anchoring element 142. The first anchoring element 141 is used to penetrate the vena cava wall to prevent the filter 100 from moving from the distal end to the proximal end, and the second anchoring element 142 is used to penetrate the vena cava wall to prevent the filter 100 from moving from the proximal end to the distal end. Furthermore, the anchoring portion 140 also includes a puncture-resistant structure 143, which limits the depth to which the first anchoring element 141 and the second anchoring element 142 penetrate the vena cava wall to avoid puncturing the vena cava wall.

[0059] Specifically, the puncture-resistant structure 143 is at least partially linear and is connected to the distal end of the second filter rod 120. The first anchor 141 is connectable to the puncture-resistant structure 143 and is located at the junction of the second filter rod 120 and the puncture-resistant structure 143. The first anchor 141 is barbed, and the free end of the barb (i.e., the end of the barb away from the puncture-resistant structure) faces towards the proximal end of the filter 100. The second anchor 142 is connected to the puncture-resistant structure 143 and is located on the distal side of the first anchor 141. The second anchor 142 is linear, and the free end of the anchor 142 faces towards the distal end of the filter 100.

[0060] More specifically, the third acute angle θ3 formed by the anti-puncture structure 143 and the axis of the filter 100 is 4° to 10°. This ensures that when the filter 100 expands in the vena cava, the anti-puncture structure 143 can abut parallel against the vena cava wall, making contact with the vena cava wall. A V-shaped structure is formed between the first anchor 141 and the second filter rod 120, with rounded corners at the sharp edges. The fourth radius R4 of the rounded corners is 0.4mm to 0.6mm, and the opening angle θ4 of the V-shaped structure is 65° to 85°. Furthermore, the length L1 of the line connecting the free end and the fixed end (i.e., the end where the first anchor 141 connects to the anti-puncture structure 143) is 0.8mm to 1.6mm. The angle θ5 formed by the second anchor 142 and the anti-puncture structure 143 is 30° to 50°, and the length L2 of the second anchor 142 is 1mm to 1.5mm. Additionally, the overall length L3 of the anti-puncture structure 143 can be 3mm to 6mm, and the distance H5 from the distal end of the anti-puncture structure 143 to the connection point between the anti-puncture structure 143 and the second anchor 142 is 1mm to 2mm. This dimensional arrangement allows for the expansion of the filter 100 within the vena cava, while also enabling the first anchor 141 and the second anchor 142 to penetrate the vena cava wall without puncturing it. Furthermore, when retrieving the filter 100, the first anchor 141 and the second anchor 142 can be smoothly withdrawn from the vena cava wall, especially allowing the first anchor 141 to be withdrawn from the vena cava wall at a near-vertical angle, reducing damage to the vena cava.

[0061] Furthermore, it is preferable that at least a portion of the first anchoring member 141 is located on different circumferences, and it is also preferable that at least a portion of the second anchoring member 142 is located on different circumferences. This has the advantage that at least a portion of the first anchoring member 141 is staggered into the vena cava wall, rather than being located on the same circumference of the vena cava wall, and at least a portion of the second anchoring member 142 is staggered into the vena cava wall, rather than being located on the same circumference of the vena cava, further reducing stimulation of the vena cava, reducing endothelial cell proliferation, and consequently reducing the encapsulation of the filter 100 by the proliferating vascular endothelium, thus allowing the filter 100 to have a longer recovery time window.

[0062] To achieve this, please refer to Figure 7 and Figure 8In the filter 100, at least some of the second filter rods 120 have unequal lengths. Preferably, all the second filter rods 120 are divided into two or more filter rod groups, with the second filter rods 120 in different filter rod groups having unequal lengths, and each filter rod group including at least two second filter rods 120 of equal length. The second filter rods 120 in the same filter rod group are arranged symmetrically about the axis of the filter 100. This structure can provide a uniform radial support force to the filter 100, so that the filter 100 remains centered. For example, please refer to... Figure 7 and Figure 8 The second filter rod 120 of the filter 100 may include three filter rod groups, wherein the lengths of the second filter rods 120 in the three filter rod groups are not equal, and each filter rod group includes two second filter rods 120 of equal length, and the two second filter rods 120 of equal length are arranged symmetrically about the axis of the filter 100. Optionally, when the second filter rod 120 of the filter 100 includes three filter rod groups, in the axial direction of the filter 100, the distance H6 from the proximal end to the distal end of the shortest second filter rod 120 is 34mm to 40mm, the distance H7 from the proximal end to the distal end of the second filter rod 120 with the middle length is 36mm to 42mm, and the distance H8 from the proximal end to the distal end of the longest second filter rod 120 is 38mm to 44mm. In addition, the diameter D3 of the third circle where the free end of the second anchor 142 of the anchoring part 140 located on the longest second filter rod 120 is located is 38mm to 42mm, so that all the first anchors 141 and the second anchors 142 can be inserted into the vena cava wall, and the puncture-proof structure 143 prevents puncture of the vena cava wall.

[0063] <Example 2>

[0064] Figure 9 shows a schematic diagram of the structure of the filter 100 provided in this embodiment. Figure 9 As shown, the difference between this embodiment and Embodiment 1 is that each anchoring portion 140 includes an anchoring element and a puncture-resistant structure 141, and the anchoring element is either the first anchoring element 141 or the second anchoring element 142. In other words, in this embodiment, the anchoring portion 140 includes a first anchoring portion 140a and a second anchoring portion 140b, wherein the first anchoring portion 140a includes the first anchoring element 141 and the puncture-resistant structure 143, and the second anchoring portion 140b includes the second anchoring element 142 and the puncture-resistant structure 143. The first anchoring portion 140a is disposed at the distal end of some of the second filter rods 120, and the second anchoring portion 140b is disposed at the distal end of other second filter rods 120.

[0065] <Example 3>

[0066] Figure 10 A schematic diagram of the filter 100 provided in this embodiment is shown. Please refer to... Figure 10 The difference between this embodiment and Embodiment 1 is that the shape of the first filter rod 110 is different, and the distance from the first filter rod 110 to the axis of the filter 100 first increases and then remains constant along the direction from the proximal end to the distal end.

[0067] In this embodiment, the first filter rod 110 includes a first arc segment 111, a first straight segment 112, a second arc segment 113, a third straight segment 116, and a fourth straight segment 117 connected sequentially from the proximal end to the distal end. The arrangement of the first arc segment 111, the first straight segment 112, and the second arc segment 113 can be referenced in Embodiment 1. The distance from the third straight segment 116 to the axis of the filter 100 gradually increases from the proximal end to the distal end, while the distance from the fourth straight segment 117 to the axis of the filter 100 remains constant. Furthermore, the fourth straight segment 117 and the third straight segment 116 can have a rounded transition or be directly connected. The third straight segment 116 is used to contact the wall of the vena cava.

[0068] <Example 4>

[0069] Figure 11 A schematic diagram of the filter 100 provided in this embodiment is shown. Figure 11 As shown, the difference between this embodiment and Embodiment 1 lies in the shape of the first filter rod 110, and the distance from the first filter rod 110 to the axis of the filter 100 increases first and then remains constant along the proximal to distal direction. That is, the first filter rod 110 includes a first arc segment 111, a first straight segment 112, a second arc segment 113, a third straight segment 116, and a fourth straight segment 117 connected sequentially along the proximal to distal direction. The arrangement of the first arc segment 111, the first straight segment 112, and the second arc segment 113 can refer to Embodiment 1. The distance from the third straight segment 116 to the axis of the filter 100 gradually increases along the proximal to distal direction, while the distance from the fourth straight segment 117 to the axis of the filter 100 remains constant. Furthermore, the fourth straight segment 117 and the third straight segment 116 can also be transitioned by a rounded corner. The third straight segment 116 is used to contact the wall of the vena cava.

[0070] The difference between this embodiment and Embodiment 1 is that the anchoring portion 140 includes a first anchoring portion 140a and a second anchoring portion 140b. The first anchoring portion 140a includes a first anchoring element 141 and the anti-puncture structure 143, and the second anchoring portion 140b includes a second anchoring element 142 and the anti-puncture structure 143. The first anchoring portion 140a is disposed at the distal end of some of the second filter rods 120, while the second anchoring portion 140b is disposed at the distal end of others.

[0071] <Example 5>

[0072] Figure 12 A schematic diagram of the filter 100 provided in this embodiment is shown. Figure 12 As shown, the difference between this embodiment and Embodiment 1 is that the shape of the second filter rod 120 is different. Specifically, in this embodiment, the second filter rod 120 has a straight configuration, and the distance from the second filter rod 120 to the axis of the filter 100 gradually increases from the proximal end to the distal end.

[0073] <Example 6>

[0074] Figure 13 A schematic diagram of the filter 100 provided in this embodiment is shown. Figure 13 As shown, the difference between this embodiment and Embodiment 1 is that the second filter rod 120 has a straight configuration, and the distance from the second filter rod 120 to the axis of the filter 100 gradually increases from the proximal end to the distal end.

[0075] The difference between this embodiment and Embodiment 1 is that the anchoring portion 140 includes a first anchoring portion 140a and a second anchoring portion 140b. The first anchoring portion 140a includes a first anchoring element 141 and the anti-puncture structure 143, and the second anchoring portion 140b includes a second anchoring element 142 and the anti-puncture structure 143. The first anchoring portion 140a is disposed at the distal end of some of the second filter rods 120, while the second anchoring portion 140b is disposed at the distal end of others.

[0076] <Example 7>

[0077] The difference between this embodiment and Embodiment 1 is that the thicknesses of the first filter rod 110 and the second filter rod 120 can be equal.

[0078] While the present invention has been disclosed above, it is not limited thereto. Those skilled in the art can make various modifications and variations to the present invention without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims and their equivalents, the present invention also intends to include such modifications and variations.

Claims

1. A filter, characterized by, The filter comprises a plurality of first filter rods and a plurality of second filter rods, the plurality of first filter rods are arranged around the axis of the filter, the plurality of second filter rods are arranged around the axis of the filter, and the proximal ends of all the first filter rods and all the second filter rods are gathered and connected to each other; the first filter rods are located outside the proximal ends of the second filter rods, and the thickness of the first filter rods is smaller than the thickness of the second filter rods The second filter rod comprises a first segment and a second segment, the first segment is partially located inside the first filter rod, the distance of the first segment to the axis of the filter increases first and then decreases in the direction from the proximal end to the distal end, the second segment is connected to the distal end of the first segment, and the distance of the second segment to the axis of the filter gradually increases in the direction from the proximal end to the distal end, so that the second filter rod forms a waist which is concave to the direction of the axis of the filter at the intersection of the first segment and the second segment; the distal end of the first filter rod is located on the proximal side of the intersection of the first segment and the second segment, and in the axial direction of the filter, the distance H4 between the distal end of the first filter rod and the intersection of the first segment and the second segment of the second filter rod is 1mm-3mm.

2. The filter of claim 1, wherein, The thickness of the first filter rod is 0.25mm-0.35mm, and the thickness of the second filter rod is 0.3mm-0.4mm.

3. The filter according to claim 1 or 2, characterized in that The surface of the second filter rod is smooth.

4. The filter according to claim 1 or 2, characterized in that The surface of the first filter rod is smooth, and the distance of the first filter rod to the axis of the filter increases first and then decreases in the direction from the proximal end to the distal end; or the distance of the first filter rod to the axis of the filter increases first and then remains unchanged in the direction from the proximal end to the distal end.

5. The filter of claim 4, wherein, The first filter rod comprises at least a first circular arc segment and a second circular arc segment, the convex side of the first circular arc segment is arranged towards the inside of the filter, the second circular arc segment is located on the distal side of the first circular arc segment, and the concave side of the second circular arc segment is arranged towards the inside of the filter.

6. The filter of claim 1, wherein, The filter further comprises an anchoring part connected to the distal end of the second filter rod, and comprising an anchoring member and a puncture-preventing structure, the anchoring member is used for penetrating into the wall of the target cavity, and the puncture-preventing structure is used for limiting the penetration depth of the anchoring member.

7. The filter of claim 6, wherein, The puncture-preventing structure is at least partially in a straight line configuration and is connected to the distal end of the second filter rod, and the third acute angle θ3 formed by the puncture-preventing structure and the axis of the filter is 4°-10°. The anchor includes a first anchor and a second anchor; the first anchor is a barb, is connected to the joint of the anti-puncture structure and the second filter rod, and a free end of the barb faces the proximal end of the filter; a V-shaped structure is formed between the first anchor and the second filter rod, an acute angle of the V-shaped structure is a rounded corner, a fourth radius R4 of the rounded corner is 0.4mm-0.6mm, an opening angle θ4 of the V-shaped structure is 65°-85°, and a length L1 of a line connecting the free end and the fixed end of the first anchor is 0.8mm-1.6mm; the second anchor is in a straight line configuration, and a free end of the second anchor faces the distal end of the filter, an acute angle θ5 of the second anchor and the anti-puncture structure is 30°-50°, and a length L2 of the second anchor is 1mm-1.5mm.

8. A filter, characterized by The filter includes a plurality of first filter rods and a plurality of second filter rods, the plurality of first filter rods are arranged around an axis of the filter, the plurality of second filter rods are arranged around the axis of the filter, and proximal ends of all the first filter rods and all the second filter rods are gathered and connected to each other; a surface of the first filter rod is smooth, and a distance of the first filter rod to the axis of the filter increases first and then decreases in a direction from the proximal end to the distal end; The second filter rod includes a first segment and a second segment, the first segment is partially located on an inner side of the first filter rod, a distance of the first segment to the axis of the filter increases first and then decreases in a direction from the proximal end to the distal end, the second segment is connected to a distal end of the first segment, and a distance of the second segment to the axis of the filter gradually increases in the direction from the proximal end to the distal end, so that the second filter rod forms a waist which is concave to the axis of the filter at an intersection of the first segment and the second segment; a distal end of the first filter rod is located on a proximal side of the intersection of the first segment and the second segment, and in an axial direction of the filter, a distance H4 of the distal end of the first filter rod to the intersection of the first segment and the second segment of the second filter rod is 1mm-3mm.

9. The filter of claim 8, wherein, A surface of the second filter rod is smooth.

10. The filter according to claim 8 or 9, characterized in that The first filter rod includes a first circular arc segment, a first straight line segment, a second circular arc segment, a third circular arc segment and a second straight line segment which are smoothly connected in sequence from the proximal end to the distal end; convex sides of the first circular arc segment and the third circular arc segment face the interior of the filter, and a concave side of the second circular arc segment faces the interior of the filter; the distance of the first straight line segment to the axis of the filter gradually increases in the direction from the proximal end to the distal end, and the distance of the second straight line segment to the axis of the filter gradually decreases in the direction from the proximal end to the distal end.

11. The filter of claim 10, wherein, The radius R1 of the first circular arc segment is 8mm-10mm, the radius R2 of the second circular arc segment is 4mm-6mm, and the radius R3 of the third circular arc segment is 5mm-8mm; the first acute angle θ1 formed by the first straight line segment and the axis of the filter is 55°-75°, and the second acute angle θ2 formed by the second straight line segment and the axis of the filter is 8°-12°.

12. The filter of claim 11, wherein, The first filter rod has a widest point, which refers to the point where the distance from the first filter rod to the axis of the filter is the largest; in the axial direction of the filter, the distance H1 between the widest point and the proximal end point of the first filter rod is 6mm-10mm, and the widest points of a plurality of the first filter rods are located on a first circle, the diameter D1 of the first circle being 28mm-30mm; the axial distance H2 between the distal end point of the first filter rod and the proximal end point of the first filter rod is 16mm-24mm, and the distal ends of a plurality of the first filter rods are located on a second circle, the diameter D2 of the second circle being 22mm-24mm.

Images