A filter recycling device

Abstract

The present invention provides a filter recovery device, including a separation unit. The separation unit includes a catheter and a separation part, and the separation part is connected to the proximal end of the catheter. The separation part is configured to be able to contract or expand radially along the catheter, and when the separation part is in the expanded state, at least part of the edge of the separation part forms a three-dimensional spiral configuration. The filter recovery device can, when recovering a filter implanted in the inferior vena cava and already wrapped by vascular endothelium, use the part of the edge of the separation part with a three-dimensional spiral configuration to cut the vascular endothelium, so as to separate the inferior vena cava wall from the filter, relieve the obstruction caused by the vascular endothelium to the filter recovery, reduce the recovery difficulty, and improve the recovery success rate.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and particularly relates to a filter recovery device. Background Art

[0002] Pulmonary embolism (PE) is a common disease. An inferior vena cava filter (hereinafter referred to as a filter) is implanted into the inferior vena cava as a medical implant to prevent thrombus detached from the inferior vena cava from reaching the lungs along the blood flow. Clinical trials have proved that filter implantation is an effective means to prevent pulmonary embolism and can effectively reduce the incidence of pulmonary embolism.

[0003] Filters can be divided into two types: permanent filters and retrievable filters. Permanent filters are used to provide a lifelong filtering function and are not retrieved after being implanted into the inferior vena cava. Long-term implantation of permanent filters may cause long-term complications such as inferior vena cava perforation, filter migration, secondary thrombosis leading to inferior vena cava occlusion, and recurrence of deep vein thrombosis. A retrievable filter refers to a filter that can be retrieved after being implanted in a patient's body for a certain period of time. After retrieval, it effectively avoids the occurrence of long-term complications, making retrievable filters widely used clinically. However, the retrievable filters in the prior art cannot be retrieved successfully one hundred percent after being implanted in a patient's body because the recovery time window of the retrievable filter is short. Once the implantation time is too long, the barbs on the filter cause endothelialization problems, resulting in varying degrees of endothelial cell overgrowth of the blood vessels, causing the endothelial cells of the blood vessels to wrap the support rods of the filter, making it difficult for the support rods to separate from the vascular endothelium, increasing the difficulty of filter recovery and easily leading to recovery failure. In addition, the filter may tilt during implantation, which also increases the difficulty of filter recovery. Summary of the Invention

[0004] The purpose of the present invention is to provide a filter recovery device for peeling off the filter and the vascular endothelium when retrieving a filter implanted in the inferior vena cava, thereby improving the success rate of filter recovery.

[0005] To achieve the above purpose, the present invention provides a filter recovery device, including a separation unit. The separation unit includes a catheter and a separation part, and the separation part is connected to the proximal end of the catheter; the separation part is configured to be able to contract or expand radially along the catheter, and when the separation part is in an expanded state, at least part of the edge of the separation part forms a three-dimensional spiral configuration.

[0006] Optionally, the separation part includes a first edge and a second edge extending along the axial direction of the catheter. The proximal end of the first edge is connected to the proximal end of the second edge, and when the separation part is in an expanded state, the first edge is in a straight configuration and the second edge is in the three-dimensional spiral configuration.

[0007] Optionally, the number of the separation parts is from 1 to 6; when the number of the separation parts is more than two, the two or more separation parts are arranged along the circumferential direction of the catheter, and adjacent separation parts are partially stacked in the circumferential direction.

[0008] Optionally, the number of the separation parts is from 2 to 3.

[0009] Optionally, both the inner diameter and the outer diameter of the separation part increase in the direction from the distal end to the proximal end.

[0010] Optionally, the filter recovery device further includes a sheath assembly, and the sheath assembly has a first channel extending axially therethrough; the separation unit is partially inserted into the first channel and is configured to be movable along the first channel;

[0011] When the separation part is located in the first channel, the separation part contracts radially, and when the separation part extends out of the first channel, the separation part expands radially.

[0012] Optionally, the proximal end portion of the sheath assembly has a straight state and a bent state.

[0013] Optionally, the sheath assembly includes a first sheath and a second sheath; the first sheath has the first channel, and the proximal end portion of the first sheath has a first pre-bent section that bends toward a first direction; the proximal end portion of the second sheath has a second pre-bent section that bends toward a second direction; the second sheath is configured to be sleeved on the outer peripheral surface of the first sheath, and the second sheath and the first sheath can perform circumferential relative movement;

[0014] The sheath assembly is configured such that when the second sheath is sleeved on the outer peripheral surface of the first sheath and the angle between the first direction and the second direction is 180°, the proximal portion of the sheath assembly is straight, and when the second sheath and the first sheath perform circumferential relative movement so that the angle between the first direction and the second direction is less than 180°, the proximal portion of the sheath assembly bends, and the smaller the angle between the first direction and the second direction, the greater the bending degree of the proximal portion of the sheath assembly.

[0015] Optionally, the bending angle of the first pre-bent section is α, and the range of α is 0 to 90°; the bending angle of the second pre-bent section is β, and the range of β is 0 to 90°, and |α - β| ≤ 10°.

[0016] Optionally, the separation part includes a framework and a covering structure, the framework is the edge of the separation part, and the covering structure covers the inner space of the framework and is connected to the framework.

[0017] Optionally, the maximum outer diameter of the separation part is 10 mm to 40 mm, and the axial dimension of the separation part is 30 mm to 80 mm.

[0018] Optionally, the catheter has a second channel extending axially therethrough; the filter recovery device further includes a capture unit configured to be partially inserted into the second channel and capable of moving along the second channel. The capture unit includes a control guide wire and a capture loop, and the capture loop is connected to the proximal end of the control guide wire.

[0019] Compared with the prior art, the filter recovery device of the present invention has the following advantages:

[0020] The aforementioned filter recovery device includes a separation unit, and the separation unit includes a catheter and a separation part. The separation part is connected to the proximal end of the catheter; the separation part is configured to be able to radially contract or expand along the catheter, and when the separation part is in the expanded state, at least part of the edge of the separation part forms a three-dimensional spiral configuration. The separation part of the filter recovery device is used to separate the filter from the vascular endothelium wrapped around the filter when recovering the filter. Specifically, when the separation part is inserted into the inferior vena cava and the separation part expands radially, the part of the edge of the separation part in the three-dimensional spiral configuration can be brought into contact with the vascular endothelium wrapped around the filter, and then the separation part is rotated. In this way, the part of the edge of the separation part in the three-dimensional spiral configuration cuts the vascular endothelium, so that the blood vessel is separated from the filter. After that, the filter can be captured by the capture unit to complete the recovery of the filter. This filter recovery device rotates the separation part and uses the edge of the separation part to cut the vascular endothelium wrapped around the filter, avoiding the obstruction of the vascular endothelium to the recovery of the filter, reducing the difficulty of filter recovery, and increasing the success rate of filter recovery. Moreover, the separation part can be manually rotated by the operator without the need to additionally introduce a driving component, making the filter recovery device a passive device with a simple structure and convenient use.

[0021] The separation part includes a first edge and a second edge extending along the axis of the catheter. The proximal ends of the first edge and the second edge are connected. When the separation part is in the expanded state, the first edge is in a straight configuration, and the second edge is in the three-dimensional spiral configuration. Such a structure enables the separation part to have a smaller outer diameter when radially contracting, so that a sheath assembly with a smaller radial dimension can be used for delivery, reducing the delivery resistance and also reducing the size of the opening on the patient's body, thereby reducing the harm to the patient.

[0022] Further, the catheter has a second channel extending axially therethrough for the capture unit to enter and exit the inferior vena cava. Also, the filter retrieval device further includes a sheath assembly having a first channel extending axially therethrough. The separating portion enters the inferior vena cava along the first channel, and after the capture unit captures the filter, the separating portion withdraws the filter out of the body through the first channel. In particular, when the proximal portion of the sheath assembly is configured to be bendable or straightenable, if the separating portion is inclined relative to the retrieval hook of the filter when the separating portion enters the inferior vena cava, the operator can control the proximal portion of the sheath assembly to bend so that the orientation of the separating portion adapts to the orientation of the filter, and then rotate the separating portion to cut the vascular endothelium. Moreover, when both the inner diameter and the outer diameter of the separating portion gradually increase in the distal-to-proximal direction, during the process of separating the filter from the vascular endothelium, the separating portion also guides the retrieval hook of the filter to gradually approach the center of the proximal end of the catheter. Thus, when the capture unit extends out from the second channel, the filter can be captured more easily, reducing the capture difficulty and further improving the retrieval success rate of the filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings are used to better understand the present invention and do not constitute an improper limitation to the present invention. Among them:

[0024] Figure 1 is a partial structural schematic diagram of a filter retrieval device according to an embodiment of the present invention;

[0025] Figure 2 is a partial structural schematic diagram of a separating unit of a filter retrieval device according to an embodiment of the present invention;

[0026] Figure 3 is Figure 2 the axial schematic diagram of the filter retrieval device shown;

[0027] Figure 4 is the axial schematic diagram of a separating unit of a filter retrieval device according to an embodiment of the present invention, showing two separating portions in the figure;

[0028] Figure 5 is the axial schematic diagram of a separating unit of a filter retrieval device according to an embodiment of the present invention, showing three separating portions in the figure;

[0029] Figure 6 is a partial structural schematic diagram of a filter retrieval device according to an embodiment of the present invention, with the connecting portion of the separating portion and the catheter not shown in the figure;

[0030] Figure 7It is a schematic structural diagram of a sheath tube assembly of a filter recovery device provided by the present invention according to an embodiment;

[0031] Figure 8 It is a schematic diagram of the assembly relationship between the sheath tube assembly of the filter recovery device provided by the present invention according to an embodiment and the separation unit;

[0032] Figure 9 It is a schematic diagram of the cooperation relationship between the sheath tube assembly of the filter recovery device provided by the present invention according to an embodiment and the dilator;

[0033] Figure 10 It is a schematic diagram of the pre-bending direction of the first sheath tube and the second sheath tube of the sheath tube assembly of the filter recovery device provided by the present invention according to an embodiment;

[0034] Figure 11 It is a schematic diagram of the pre-bending angle of the first sheath tube of the sheath tube assembly of the filter recovery device provided by the present invention according to an embodiment;

[0035] Figure 12 It is a schematic diagram of the pre-bending angle of the second sheath tube of the sheath tube assembly of the filter recovery device provided by the present invention according to an embodiment;

[0036] Figure 13 It is a schematic diagram of the application scenario of the filter recovery device provided by the present invention according to an embodiment, and the figure shows a schematic diagram of the separation part peeling off the vascular endothelium and the filter;

[0037] Figure 14 It is a schematic diagram of the application scenario of the filter recovery device provided by the present invention according to an embodiment. In the figure, the recovery hook of the filter is guided by the separation part to the proximal center attachment of the catheter, and the capture unit captures the filter.

[0038] [Explanation of reference numerals is as follows]:

[0039] 100 - separation unit, 110 - catheter, 111 - second channel, 112 - catheter body, 113 - connection part, 114 - catheter seat, 120 - separation part, 121 - first edge, 122 - second edge, 123 - coating structure, 200 - capture unit, 210 - conduction wire, 220 - capture ring, 230 - drive mechanism, 300 - sheath tube assembly, 301 - first channel, 310 - first sheath tube, 320 - second sheath tube, 330 - first sheath tube seat, 340 - second sheath tube seat;

[0040] 10 - filter, 11 - recovery hook;

[0041] 20 - dilator. Detailed implementation manners

[0042] The following uses specific specific examples to illustrate the implementation manners 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 implementation manners. 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 diagrams provided in this embodiment only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The types, quantities, and proportions of the components in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0043] In addition, each of the following description embodiments has one or more technical features. However, this does not mean that those using the present invention must implement all the technical features in any one embodiment at the same time, or can only separately implement some or all of the technical features in different embodiments. In other words, on the premise that implementation is possible, those skilled in the art can, according to the disclosure of the present invention and depending on design specifications or implementation requirements, selectively implement some or all of the technical features in any one embodiment, or selectively implement the combination of some or all of the technical features in multiple embodiments, thereby increasing the flexibility when implementing the present invention.

[0044] As used in this specification, the singular forms "a", "an", and "the" include plural objects, and the plural form "plural" includes more than two objects, unless the content clearly indicates otherwise. As used in this specification, the term "or" is generally used in the sense of including "and / or", unless the content clearly indicates otherwise, and the terms "mounted", "connected", "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be directly connected or indirectly connected through an intermediate medium. It can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] In this article, the terms "proximal" and "distal" are the relative orientations, relative positions, and directions of elements or actions relative to each other from the perspective of a doctor using the medical device. Although "proximal" and "distal" are not restrictive, "distal" generally refers to the end of the medical device that is closer to the doctor during normal operation, while "proximal" generally refers to the end that first enters the patient's body.

[0046] 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 in very simplified forms and use non-precise scales, and are only used to conveniently and clearly assist in explaining the objectives of the embodiments of the present invention. The same or similar reference numerals in the drawings represent the same or similar components.

[0047] Figure 1 FIG. shows a partial structural schematic diagram of a filter recovery device provided by an embodiment of the present invention. As Figure 1 shown, the filter recovery device includes a separation unit 100, and the separation unit 100 includes a catheter 110 and a separation part 120. The separation part 120 is connected to the proximal end of the catheter 110 and extends along the axial direction of the catheter 110. The separation part 120 is configured to be able to contract or expand radially along the catheter 110, and when the separation part 120 is in an expanded state, at least part of the edge of the separation part 120 forms a three-dimensional spiral configuration. In other words, when the separation part 120 is in an expanded state, the separation part 120 has a channel, and the proximal side wall of the channel has a spiral incision. It can be understood that the "edge" is the part along the edge of the separation part 120 and is also the edge part of the separation part 120 away from the center.

[0048] The filter recovery device can be used to recover a filter 10 implanted in the inferior vena cava and at least partially wrapped by vascular endothelium (such as Figure 13 and Figure 14 shown). The specific process is to send the separation part 120 in a radially contracted state into the inferior vena cava, then expand the separation part 120 radially, and make the part of the edge of the separation part 120 with a three-dimensional spiral configuration contact the vascular endothelium. Then the operator manipulates the catheter 110 to rotate, thereby driving the separation structure to rotate, so that the part of the edge of the separation part 120 with a three-dimensional spiral configuration can cut the vascular endothelium covering the filter 10, so as to strip the filter 10 from the blood vessel and remove the obstacle of the vascular endothelium to the recovery of the filter 10. After that, the recovery hook 11 of the filter 10 can be captured by any suitable method.

[0049] Please continue to refer to Figure 1 and in combination with Figure 6, in an optional implementation, the catheter 110 has a second channel 111 extending therethrough along its axial direction. The filter retrieval device may further include a capture unit 200, which includes a conductive wire 210 and a capture loop 220. The capture loop 220 is connected to the proximal end of the conductive wire 210. The capture unit 200 is configured to be partially disposed in the second channel 111 of the catheter 110 and be movable along the second channel 111 under the action of an external force, so that the capture loop 220 can enter the inferior vena cava along the second channel 111, and can also be rotated under the action of an external force to adjust the orientation of the capture loop 220 to capture the filter 10. Optionally, the distal end of the conductive wire 210 extends out of the second channel 111, and the capture unit 200 further includes a driving mechanism 230. The driving mechanism 230 is connected to the distal end of the conductive wire 210 and is configured to receive the external force. That is to say, the operator can apply the external force to the driving mechanism 230 to move the conductive wire 210 along the second channel 111, thereby causing the capture loop 220 to extend out of or retract into the second channel 111. Moreover, the operator can also apply the external force to the driving mechanism 230 to cause the conductive wire 210 to rotate, thereby driving the capture loop 220 to rotate.

[0050] Thus, the filter retrieval device provided by the embodiment of the present invention cuts the vascular endothelium covering the filter 10 through the edge of the separation part 120 of the separation unit 100 to relieve the obstruction caused by the vascular endothelium to the retrieval of the filter 10, reduce the difficulty of retrieving the filter 10, and improve the retrieval success rate. Moreover, the operator can manually drive the catheter 110 to rotate and drive the separation part 120 to rotate without additionally introducing a driving component, making the separation unit 100 a passive structure, which is simpler in structure and more convenient to use.

[0051] In a non-limiting embodiment, as Figure 2 and Figure 3 shown, the edge part of the separation part 120 partially forms the three-dimensional spiral configuration. Specifically, the separation part 120 includes a first edge 121 and a second edge 122 extending along the axial direction of the catheter 110. The distal ends of the first edge 121 and the second edge 122 are connected to the proximal end of the catheter 110, and the proximal ends of the first edge 121 and the second edge 122 are connected to each other. When the separation part 120 is in the expanded state, the first edge 121 is in a straight configuration, and the second edge 122 is in the three-dimensional spiral configuration. Thus, the angle at which the second edge 122 extends around the axis of the catheter 110 is less than 360°. Such a structure can make the separation part 120 have a smaller outer diameter when radially contracting, so that it can use a sheath assembly 300 with a smaller radial dimension (such asFigure 7 and Figure 8 as shown) into the inferior vena cava. Those skilled in the art can understand that the "flat configuration" is a straight line shape.

[0052] In addition, the separation part 120 can be wound by a planar structure of any shape and then cut to form the first edge 121 and the second edge 122.

[0053] Alternatively, the separation part 120 can be formed by winding a planar structure with a suitable shape. That is to say, the planar structure has two interconnected edges. When winding, one edge forms the first edge 121 and the other edge forms the second edge 122. For example, the separation part 120 can include a skeleton and a covering structure 123. The material of the skeleton can be shape memory alloy wire, such as nitinol wire. The skeleton forms the edges of the separation part 120. That is, a part of the skeleton is pre-shaped into the first edge 121 in a flat configuration, and another part of the skeleton is pre-shaped into the second edge 122 in a three-dimensional spiral configuration. The covering structure 123 covers the inner space of the first edge 121 and the second edge 122, and connects the covering structure 123 and the skeleton in any suitable way such as heat melting or sewing or bonding. Optionally, the cross-section of the skeleton can be rectangular or circular. When the cross-section of the skeleton is circular, preferably the diameter of the skeleton is 0.3 mm to 0.5 mm. The covering structure 123 can allow blood to pass through or not, and the covering structure 123 does not allow thrombus to pass through. The covering structure 123 can be a polymer membrane material such as PTFE, or a mesh structure woven from PET filaments or other polymer filaments, and the thickness of the covering structure 123 is not more than 0.1 mm.

[0054] Optionally, please continue to refer to Figure 2 and Figure 3 , the inner diameter and the outer diameter of the separation part 120 both gradually increase in the direction from the distal end to the proximal end. Thus, on the axial projection of the separation unit 100, the projection line of the second edge 122 is also a spiral line. Optionally, the maximum outer diameter of the separation part 120 is 10 mm to 40 mm, which is specifically set according to the diameter of the inferior vena cava, so that the maximum outer diameter of the separation part 120 is equivalent to the diameter of the inferior vena cava. The advantage of this is that when the filter recovery device enters the inferior vena cava from the jugular vein approach to recover the filter 10 (that is, the recovery hook 11 of the filter 10 is located at the proximal end of the filter 10), the separation part 120 can also cover the cross-section of the inferior vena cava to the greatest extent to intercept thrombus and prevent thrombus from flowing into the heart with the blood flow.

[0055] Here, please continue to refer to Figure 2and Figure 3 , and in combination with Figure 4 and Figure 5 , the number of the separation parts 120 is at least one, for example, the number of the separation parts 120 is 1 to 6. When the number of the separation parts 120 is more than two, the two or more separation parts 120 are arranged along the circumferential direction of the catheter 110, and two adjacent separation parts 120 are partially stacked in the circumferential direction. Here, when the number of the separation parts 120 is multiple, the multiple separation parts 120 are collectively referred to as a separation structure. It can be understood that the more the number of the separation parts 120, the closer the outer shape of the separation structure is to a conical shape, and the stronger the ability of the separation structure to intercept thrombus at the proximal end of the filter 10. However, the more the number of the separation parts 120, the greater the manufacturing difficulty of the separation structure. At the same time, when the multiple separation parts 120 radially contract, the outer diameter of the separation structure will increase due to the rotational folding of the multiple separation parts 120, which is not conducive to being transported by the sheath assembly 300 with a smaller radial size. Based on this, it is preferred that the number of the separation parts 120 is 2 or 3.

[0056] In addition, the axial dimension of the separation part 120 is 30 mm to 80 mm, which is specifically set according to the axial dimension of the filter 10 so that the axial dimension of the separation part 120 is equivalent to the axial dimension of the filter 10. And, the catheter 110 may include a catheter body 112, a connection part 113, and a catheter seat 114. The distal end of the connection part 113 is connected to the proximal end of the catheter body 112, and the proximal end of the connection part 113 is connected to the distal end of the separation part 120. The connection methods include but are not limited to gluing, injection molding, screw connection, etc. The catheter seat 114 is connected to the distal end of the catheter body 112.

[0057] Further, please refer to Figure 7 and Figure 8, the filter recovery device further includes the sheath assembly 300, and the sheath assembly 300 has a first channel 301 extending therethrough axially. The separation unit 100 is configured to be partially inserted into the first channel 301 and is configured to be movable along the first channel 301. Specifically, when recovering the filter 10, the proximal end of the sheath assembly 300 is first introduced into the inferior vena cava, and then the separation structure of the separation unit 100 is inserted into the first channel 301. The operator pushes the separation unit 100 along the first channel 301 so that the separation structure extends out of the distal end of the first channel 301 and enters the inferior vena cava. It can be understood that when the separation structure is located within the first channel 301, the inner wall of the first channel 301 applies a radially inward squeezing force to the separation portion 120, causing the separation portion 120 to radially contract (i.e., the separation structure is in a contracted state). When the separation structure extends out of the first channel 301, the inner wall of the first channel 301 no longer applies a radially inward squeezing force to the separation portion 120, so that the separation portion 120 expands radially, causing the entire separation structure to expand radially. It can also be understood that during the process of introducing the proximal end of the sheath assembly 300 into the inferior vena cava, the sheath assembly 300 cooperates with the dilator 20 (as Figure 9 shown), specifically, the dilator 20 is partially inserted into the first channel 301, and the proximal end of the dilator 20 extends out of the proximal end of the first channel 301, and then the proximal ends of the dilator 20 and the sheath assembly 300 are introduced into the inferior vena cava according to conventional methods. After the dilator 20 is withdrawn, the separation unit 100 can be delivered through the first channel 301.

[0058] Those skilled in the art know that the filter 10 may tilt in the inferior vena cava, or even if the filter 10 remains centered in the inferior vena cava (i.e., the axis of the filter 10 is substantially coincident with the axis of the inferior vena cava), but because the human blood vessels are not straight, the proximal end of the sheath assembly 300 may abut against one side of the inferior vena cava wall, resulting in the separation portion 120 tilting relative to the filter 10 when extending out of the first channel 301, so that the second edge 122 of the separation portion 120 cannot smoothly contact and wrap the vascular endothelium on the filter 10.

[0059] In view of this, the proximal end of the sheath assembly 300 is configured to be bendable or straightenable, that is, the sheath assembly 300 has a straightened state and a bent state, so that the operator can rotate the sheath assembly 300 according to the actual situation and control the bending of its proximal part to adjust the relative orientation between the proximal end of the sheath assembly 300 and the retrieval hook 11 of the filter 10, so that after the separation part 120 extends out of the second channel 301, the second edge 122 of the separation part 120 can smoothly contact the vascular endothelium wrapped on the filter 10, and the retrieval hook 11 is located inside the separation part 120.

[0060] In this embodiment, please continue to refer to Figures 7 to 9 , the sheath assembly 300 includes a first sheath 310 and a second sheath 320, and the first sheath 310 has the first channel 301. The proximal end of the first sheath 310 is pre-bent so that the proximal end of the first sheath 310 has a first pre-bent section, and the axis of the first pre-bent section is as shown by the line s1 in Figures 10 to 12 . The proximal end of the second sheath 320 is also pre-bent so that the proximal end of the second sheath 320 has a second pre-bent section, and the axis of the second pre-bent section is as shown by the line s2 in Figures 10 to 12 . In this article, the pre-bending direction of the first sheath 310 is called the first direction A1, and the pre-bending direction of the second sheath 320 is called the second direction A2.

[0061] The second sheath tube 320 is used to be sleeved on the outer peripheral surface of the first sheath tube 310, and when the second sheath tube 320 is assembled with the first sheath tube 310, the two can perform circumferential relative movement. In this embodiment, the bending force of the first pre-bent section is equal to the bending force of the second pre-bent section. Thus, when the second sheath tube 320 is sleeved on the outer peripheral surface of the first sheath tube 310, and the first direction A1 is opposite to the second direction A2, that is, the angle between the second direction A1 and the first direction A2 is 180°, since the direction of the bending force of the first pre-bent section is opposite to the direction of the bending force of the second pre-bent section, the bending forces of the two cancel each other out, and further the proximal part of the sheath tube assembly 300 does not bend (i.e., is in a straight form). When the first sheath tube 310 and the second sheath tube 320 perform circumferential relative movement so that the angle between the first direction A1 and the second direction A2 is less than 180°, the bending force of the first pre-bent section and the bending force of the second pre-bent section cannot cancel each other out, so the proximal part of the sheath tube assembly 300 bends. It can be understood that the smaller the angle between the first direction A1 and the second direction A2, the greater the bending degree of the proximal part of the sheath tube assembly 300. In other words, the operator can adjust the bending degree of the proximal part of the sheath tube assembly 300 by controlling the circumferential relative movement of the first sheath tube 310 and the second sheath tube 320. This bending adjustment method has the advantages of simple structure, convenient operation and low cost.

[0062] In this embodiment, the bending angle of the first pre-bent section is α, and the range of α is 0 to 90°; the bending angle of the second proximal pre-bent section is β, and the range of β is 0 to 90°, and |α - β| ≤ 10°. In addition, the anti-bending coefficients of the first sheath tube 310 and the second sheath tube 320 can be equal or not equal. When the anti-bending coefficients of the two are not equal, for example, the anti-bending coefficient of the first sheath tube 310 is less than the anti-bending coefficient of the second sheath tube 320, then the bending angle α of the first pre-bent section can be greater than the bending angle β of the second pre-bent section. On the contrary, if the anti-bending coefficient of the first sheath tube 310 is greater than the anti-bending coefficient of the second sheath tube 320, then the bending angle α of the first pre-bent section can be less than the bending angle β of the second pre-bent section. Here, the bending angle refers to the angle formed by the tangent line of the distal end point of the pre-bent section and the tangent line of the proximal end point of the pre-bent section.

[0063] In addition, the sheath tube assembly 300 further includes a first sheath tube seat 330 and a second sheath tube seat 340. The first sheath tube seat 330 is a hollow structure and is connected to the distal end of the first sheath tube 330. The second sheath tube 340 is also a hollow structure and is connected to the distal end of the second sheath tube 320.

[0064] Next, taking the retrieval hook 11 of the filter 10 located at the proximal end of the filter 10 as an example, the usage process of the filter retrieval device provided by the embodiment of the present invention will be introduced.

[0065] First, assemble the dilator 20 and the sheath assembly 300, and make the first direction s1 opposite to the second direction s2 (that is, the proximal part of the sheath assembly 300 is in a straight state). Then, the operator introduces the proximal ends of the dilator 20 and the sheath assembly 300 into the inferior vena cava from the jugular vein by a conventional method. After that, withdraw the dilator 20 from the body.

[0066] Next, the operator inserts the separation structure of the separation unit 100 into the first channel 301, and pushes the separation unit 100 by applying an external force to the driving mechanism 230, so that the proximal end of the separation structure reaches the proximal end of the first channel 301. Continue to push the separation unit 100 to make the separation structure partially extend out of the first channel 301. Then observe whether the separation structure is inclined relative to the retrieval hook of the filter 10. If not, continue to push the separation unit 100 until the second edge 122 of the separation part 120 contacts the vascular endothelium wrapped around the filter 10. If so, the operator controls the circumferential relative movement of the first sheath 310 and the second sheath 320 to bend the distal end of the sheath assembly 300, and controls the bending angle and bending direction until the orientation of the separation structure matches the orientation of the retrieval hook 11 of the filter 10, so that the separation part 120 is located on the outer periphery of the retrieval hook 11 of the filter 10, and the second edge 122 can contact the vascular endothelium wrapped around the filter 10. Then, continue to push the separation unit 100 until the second edge 122 of the separation part 120 contacts the vascular endothelium wrapped around the filter 10.

[0067] Next, the operator continues to push the separation unit 100 while also controlling the rotation of the separation structure (as Figure 13 shown), so that the second edge 122 cuts the vascular endothelium to strip the filter 10 and the blood vessel wall. It can be understood that when looking from the distal end to the proximal end, if the spiral direction of the second edge 122 is clockwise, the rotation direction of the separation structure is counterclockwise. In addition, during the process of the second edge 122 cutting the vascular endothelium, the retrieval hook 11 of the filter 10 gradually approaches the center of the proximal end of the catheter 110 along the inner surface of the separation part 120 (mainly the inner surface near the second edge 122).

[0068] Next, the operator introduces the capture loop 220 of the capture unit 200 into the inferior vena cava along the second channel 111 of the catheter 110. After the capture loop 220 extends from the proximal end of the second channel 111, it can successfully enclose the retrieval hook 11 (as Figure 14 shown).

[0069] Next, the operator pushes the catheter 110 to contract the capture loop 220, so that the capture loop 220 tightly encloses the retrieval hook 11 to prevent the two from separating. In addition, since the axial dimension of the separation portion 120 is equivalent to the axial dimension of the filter 10, when the proximal end of the catheter 110 contacts the distal end of the retrieval hook 11, the separation portion 120 can completely wrap the filter 10 to prevent the thrombus on the filter 10 from escaping.

[0070] Finally, the operator pushes the first sheath 310 forward to receive the separation portion 120 into the first channel 301. Then, the sheath assembly 300, the capture unit 200, and the separation unit 100 are withdrawn from the body together to complete the retrieval of the filter 10.

[0071] It can be understood that before the separation unit 100 is introduced into the inferior vena cava, the separation unit 100 and the capture unit 200 can be pre-assembled together, as long as the capture loop 220 is kept within the second channel 111 before the filter 10 is peeled off from the inferior vena cava wall. In addition, when the retrieval hook 11 is located at the distal end of the filter, the filter retrieval device can also be accessed through the femoral vein to retrieve the filter 10.

[0072] In the technical solution provided by the embodiment of the present invention, the three-dimensional spiral configuration part at the edge of the separation portion cuts and wraps the vascular endothelium on the filter, so that the filter is peeled off from the inferior vena cava wall, removing the obstacle of the vascular endothelium to filter retrieval and improving the success rate of filter retrieval. When the filter retrieval device accesses through the jugular vein to retrieve the filter, the conical-like structure of the separation portion can also at least partially cover the cross-section of the inferior vena cava on the proximal side of the filter to intercept the thrombus detached from the filter. Moreover, when the filter is inclined relative to the separation structure, the relative pose of the two can be adjusted by controlling the bending of the proximal part of the sheath assembly, so that the separation portion can smoothly cut the blood vessel lumen. And when the inner diameter of the separation portion gradually increases from the distal end to the proximal end, during the process of cutting the vascular endothelium, the separation portion also guides the retrieval hook of the filter, so that the retrieval hook moves near the center of the proximal end of the catheter, facilitating the capture of the retrieval hook by the capture loop extending from the second channel of the catheter, further improving the success rate of filter retrieval.

[0073] Although the present invention is disclosed as above, it is not limited thereto. Those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations therein.

Claims

1. A filter recycling device, characterized in that, Comprising a separation unit, the separation unit includes a catheter and a separation part, the separation part is connected to the proximal end of the catheter, the number of the separation parts is from 1 to 6, when the number of the separation parts is more than two, the two or more separation parts are arranged along the circumferential direction of the catheter, and the adjacent separation parts are partially stacked in the circumferential direction; the separation part is configured to be able to contract or expand radially along the catheter, and when the separation part is in the expanded state, at least part of the edge of the separation part forms a three-dimensional spiral configuration; the separation part includes a first edge and a second edge extending along the axial direction of the catheter, the proximal end of the first edge is connected to the proximal end of the second edge, and when the separation part is in the expanded state, the first edge is in a straight configuration and the second edge is in the three-dimensional spiral configuration.

2. The filter recovery device according to claim 1, wherein The number of the separation parts is from 2 to 3.

3. The filter recycling device according to claim 1, characterized in that, Both the inner diameter and the outer diameter of the separation part increase in the direction from the distal end to the proximal end.

4. The filter recycling device according to any one of claims 1-3, characterized in that, The filter recovery device further includes a sheath assembly having a first channel extending axially therethrough; the separation unit is partially inserted into the first channel and is configured to be movable along the first channel; When the separation part is located in the first channel, the separation part contracts radially, and when the separation part extends out of the first channel, the separation part expands radially.

5. The filter recycling device according to claim 4, wherein The proximal end portion of the sheath assembly has a straight state and a bent state.

6. The filter recovery device according to claim 5, characterized in that, The sheath assembly includes a first sheath and a second sheath; the first sheath has the first channel, and the proximal end portion of the first sheath has a first pre-bent section bent in a first direction; the proximal end portion of the second sheath has a second pre-bent section bent in a second direction; the second sheath is for sleeving on the outer peripheral surface of the first sheath, and the second sheath and the first sheath can perform circumferential relative movement; The sheath assembly is configured such that when the second sheath is sleeved on the outer peripheral surface of the first sheath and the angle between the first direction and the second direction is 180°, the proximal portion of the sheath assembly is straightened, and when the second sheath and the first sheath perform circumferential relative movement to make the angle between the first direction and the second direction less than 180°, the proximal portion of the sheath assembly is bent, and the smaller the angle between the first direction and the second direction is, the greater the bending degree of the proximal portion of the sheath assembly is.

7. The filter recovery device according to claim 6, characterized in that, The bending angle of the first pre-bent section is α, and the range of α is from 0 to 90°; the bending angle of the second pre-bent section is β, and the range of β is from 0 to 90°, and |α - β| ≤ 10°.

8. The filter recycling device according to claim 1, characterized in that, The separation part includes a framework and a covering structure, the framework is the edge of the separation part, and the covering structure covers the inner space of the framework and is connected to the framework.

9. The filter recovery device according to claim 1, wherein, The maximum outer diameter of the separation part is from 10 mm to 40 mm, and the axial dimension of the separation part is from 30 mm to 80 mm.

10. The filter recovery device according to claim 1, wherein, The catheter has a second channel extending axially therethrough; the filter recovery device further includes a capture unit, the capture unit is configured to be partially inserted into the second channel and is configured to be movable along the second channel, the capture unit includes a control guide wire and a capture loop, and the capture loop is connected to the proximal end of the control guide wire.

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