Thrombectomy device

Abstract

Disclosed is a thrombectomy device (1), which comprises a cutting stent (10) with an inner cavity, wherein the cutting stent (10) is a grid structure composed of a plurality of grid units (12), and each grid unit (12) comprises a plurality of support rods (121) connected end to end; the cutting stent (10) comprises a cutting part (11) located at the proximal end, and the cutting stent (10) comprises a first extension region (14), a second extension region (15), a third extension region (16), and a fourth extension region (17) which are extending in the axial direction; the first extension region (14), the second extension region (15), the third extension region (16), and the fourth extension region (17) are sequentially arranged and connected in the circumferential direction, and the cutting part (11) is connected to the proximal ends of the first extension region (14), the second extension region (15), the third extension region (16), and the fourth extension region (17); a distal end portion (111) of the cutting part (11) is adjacent to a proximal end portion of the first extension region (14), and a proximal end portion (112) of the cutting part (11) is adjacent to a proximal end portion of the third extension region (16); the hardness of the first extension region (14) is greater than the hardness of the second extension region (15) and the fourth extension region (17), and the hardness of the third extension region (16) is greater than the hardness of the second extension region (15) and the fourth extension region (17). The cutting part (11) of the thrombectomy device (1) is not easily separated from the blood vessel wall.

Description

Thrombus extraction device TECHNICAL FIELD

[0001] The present application relates to the technical field of medical devices, and in particular to a thrombus extraction device. BACKGROUND

[0002] The background section provided herein is merely for information and is not necessarily prior art.

[0003] Referring to FIG. 1, a thrombus extraction device 1' known to the applicant includes a thrombus extraction stent 10' and a stretch tube 20'.

[0004] The thrombus extraction stent 10' includes a plurality of mesh rods 11' connected end to end, and the thrombus extraction stent 10' forms an inner cavity. The proximal end of the thrombus extraction stent 10' forms an opening portion 12' that communicates with the inner cavity. The opening portion 12' is a beveled opening (rather than a flat opening perpendicular to the axial direction). The distal end of the stretch tube 20' is connected to the proximal end of the thrombus extraction stent 10'. During thrombus extraction, the thrombus extraction stent 10' is delivered to the distal end of the thrombus. The stretch tube 20' is driven to move the thrombus extraction stent 10' proximally in the blood vessel under the action of tension. The opening portion 12' of the thrombus extraction stent 10' can separate the thrombus on the inner wall of the blood vessel from the blood vessel wall, so that the thrombus is captured in the inner cavity of the thrombus extraction stent 10' and the captured thrombus is taken out of the patient's body by the thrombus extraction stent 10'.

[0005] In some applications, the inner diameter of the blood vessel gradually decreases along the movement direction of the thrombus extraction stent 10', and the opening portion 12' is a beveled opening. Therefore, when the thrombus extraction stent 10' enters the blood vessel with a smaller inner diameter from the blood vessel with a larger inner diameter, the part of the opening portion 12' located at the proximal end enters the blood vessel with a smaller inner diameter first, which easily causes the mesh rods 11' to be concentrated at the distal end of the opening portion 12', and further causes the mesh rods 11' near the distal end to be folded inward under the action of the radial inward force exerted by the inner wall of the blood vessel, forming a depression 121' at the distal end as shown in FIG. 2, and further causing the opening portion 12' to separate from the inner wall of the blood vessel at the depression 121', resulting in a lower thrombus extraction efficiency.

[0006] SUMMARY

[0007] Therefore, it is necessary to provide a thrombus extraction device with an opening portion that is less likely to separate from the blood vessel wall.

[0008] The application discloses a kind of taking plug devices, including cutting support with inner cavity, the cutting support is grid structure with multiple grid units, each described grid unit includes multiple support rods connected head to tail, the cutting support includes cutting part located in proximal end, the cutting part is the opening communicated with the inner cavity, the cutting part includes proximal end and distal end, the cutting support includes first extension zone, second extension zone, third extension zone and fourth extension zone extending in axial direction, the first extension zone, the second extension zone, the third extension zone and the fourth extension zone are sequentially arranged and connected in circumferential direction, the cutting part is connected with the proximal end of the first extension zone, second extension zone, third extension zone and fourth extension zone, and the distal end of the cutting part is adjacent to the proximal end of the first extension zone, the proximal end of the cutting part is adjacent to the proximal end of the third extension zone, the first extension zone and the third extension zone are radially opposite, the second extension zone and the fourth extension zone are radially opposite, the hardness of the first extension zone is greater than the hardness of the second extension zone, the hardness of the first extension zone is greater than the hardness of the fourth extension zone, the hardness of the third extension zone is greater than the hardness of the second extension zone, and the hardness of the third extension zone is greater than the hardness of the fourth extension zone.

[0009] The taking plug device described above includes cutting support, cutting support includes first extension zone, second extension zone, third extension zone and fourth extension zone extending in axial direction, first extension zone, second extension zone, third extension zone and fourth extension zone are sequentially arranged and connected in circumferential direction, first extension zone and third extension zone are radially opposite, second extension zone and fourth extension zone are radially opposite. The distal end of the cutting part is adjacent to the proximal end of the first extension zone, and the proximal end of the cutting part is adjacent to the proximal end of the third extension zone. The taking plug device provided by the embodiment of the application sets the hardness of the first extension zone to be greater than the hardness of the second extension zone, and sets the hardness of the first extension zone to be greater than the hardness of the fourth extension zone, so that in the process of gradually entering the cutting support into the blood vessel with small inner diameter, the support rods in the second extension zone and the fourth extension zone are deformed in the circumferential direction at a greater amplitude than the support rods in the first extension zone, thereby reducing or avoiding excessive accumulation of the support rods in the first extension zone, avoiding excessive accumulation of the support rods near the distal end of the cutting part, and reducing or avoiding the support rods near the distal end of the cutting part from being folded inward due to excessive accumulation, so as to improve the wall adhesion of the distal end of the cutting part in the blood vessel. Moreover, the hardness of the third extension zone is greater than the hardness of the second extension zone, and the hardness of the third extension zone is greater than the hardness of the fourth extension zone, so that the third extension zone can have relatively high hardness, thereby reducing the amplitude of being stretched in axial direction during the process of taking plug, reducing the amplitude of being deformed inward due to the axial elongation of the cutting part, and improving the wall adhesion of the cutting part. Therefore, the wall adhesion of the taking plug device provided by the embodiment of the application is better. BRIEF DESCRIPTION OF DRAWINGS

[0010] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiments description. Obviously, the drawings described in the following are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without any creative effort.

[0011] Wherein:

[0012] Fig. 1 is a structural schematic diagram of a thrombus extraction device known to the applicant;

[0013] Fig. 2 is a diagram of a state in which the distal end of the opening part of a thrombus extraction stent known to the applicant is inwardly recessed;

[0014] Fig. 3 is a perspective view of a thrombus extraction device according to an embodiment;

[0015] Fig. 4 is an exploded perspective view of the thrombus extraction device according to an embodiment;

[0016] Fig. 5 is a structural schematic diagram of the thrombus extraction device according to an embodiment;

[0017] Fig. 6 is a plan view of Fig. 5;

[0018] Fig. 7A is a diagram of a state in which a first stent according to an embodiment is expanded in a planar state after being cut from the distal end of the cutting part along the axial direction of the cutting stent;

[0019] Fig. 7B is a diagram of a state in which the first extension area of the first stent shown in Fig. 7A is expanded in a planar state;

[0020] Fig. 7C is a diagram of a state in which the second extension area and the third extension area of the first stent shown in Fig. 7A are expanded in a planar state;

[0021] Fig. 7D is a diagram of a state in which the fourth extension area of the first stent shown in Fig. 7A is expanded in a planar state;

[0022] Fig. 7E is a diagram of a state in which the cutting part of the first stent shown in Fig. 7A is expanded in a planar state;

[0023] Fig. 8 is a diagram of a state in which part of the structure of the first stent shown in Fig. 7A is expanded in a planar state. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings of the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, and not all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without any creative effort are within the scope of the present application.

[0025] In the description of the embodiments of the present application, it should be noted that the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the embodiments of the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0026] In the description of the embodiments of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be replaceably connected, or it can be integrally connected, it can be mechanically connected, or it can be electrically connected, it can be directly connected, or it can be indirectly connected through an intermediate medium, it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0027] In the field of interventional medical devices, the end of a medical device implanted in the human or animal body closer to the operator is generally referred to as the "proximal end", and the end farther from the operator is referred to as the "distal end", and the "proximal end" and "distal end" of any component of the medical device are defined according to this principle. "Axial" generally refers to the length direction of the medical device when it is being delivered, and "radial" generally refers to the direction of the medical device that is not parallel to its "axial" direction, and the "axial" and "radial" directions of any component of the medical device are defined according to this principle. "Circumferential" refers to the circumferential direction, i.e. the direction around the axis of the lumen structure, the cylinder.

[0028] Please refer to FIG. 3 and FIG. 4, the present disclosure provides a thrombectomy device 1, which can be used to remove a thrombus in a blood vessel of a patient. The thrombectomy device 1 comprises a cutting stent 10, a push-pull tube 20, and an outer tube 30, wherein the distal end of the push-pull tube 20 is connected to the proximal end of the cutting stent 10, and the outer tube 30 is slidably sleeved on the push-pull tube 20. The outer tube 30 can slide axially along the push-pull tube 20 to load and release the cutting stent 10.

[0029] The cutting stent 10 is a mesh structure having an inner cavity. The mesh structure comprises a plurality of mesh units 12, each of which comprises a plurality of support rods 121 connected end to end, and the hollow part of each mesh unit 12 is a mesh hole. The cutting stent 10 can be woven by a woven wire and then heat set. The cutting stent 10 can also be cut from a hollow pipe and then heat set. The woven wire can be a nickel-titanium alloy wire, a stainless steel wire or other metal wire. The hollow pipe can be a nickel-titanium alloy pipe, a stainless steel pipe or other metal pipe, or a polymer pipe.

[0030] The cutting stent 10 has radial compressibility and can be compressed to a loading size under the constraint force (a radial compression force on the cutting stent 10 or an axial tension force applied to both ends of the cutting stent 10) so that the cutting stent 10 is loaded in the outer tube 30, thereby being delivered in the blood vessel of the patient through the outer tube 30. When reaching the intended position, the outer tube 30 is moved proximally relative to the cutting stent 10 and the push-pull tube 20 to expose the cutting stent 10.

[0031] The cutting stent 10 has self-expanding property and can expand to a radially expanded state when the constraint force acting on the cutting stent 10 is removed. For example, after the outer tube 30 sheathed on the cutting stent 10 is removed and separated from the cutting stent 10, the cutting stent 10 can radially self-expand to a radially expanded state.

[0032] Please continue to refer to FIGS. 3 and 4, the proximal end of the cutting stent 10 forms a cutting part 11 communicating with the inner cavity, and the cutting part 11 is a circumferentially closed structure that can cut thrombus when moving in the blood vessel under the action of external force.

[0033] Please continue to refer to FIGS. 3 and 4, the cutting part 11 comprises a distal end 111 and a proximal end 112, and the distal end 111 is located distally of the proximal end 112. When the cutting stent 10 is located in the blood vessel and the constraint force acting on the cutting stent 10 is removed, the cutting stent 10 can self-expand to a radially expanded state, so that the cutting part 11 is in close contact with the inner wall of the blood vessel.

[0034] Please refer to FIGS. 3 and 4, the thrombus removal device 1 further comprises a mounting ring 41 connected to the proximal end 112 of the cutting part 11 through a connecting rod 51.

[0035] The push-pull tube 20 is a hollow tubular structure. The distal end of the push-pull tube 20 is connected to the mounting ring 41, and thus connected to the proximal end 112 of the cutting portion 11 through the mounting ring 41 and the connecting rod 51, so that the push-pull tube 20 can exert a force on the cutting stent 10, thereby pushing the cutting stent 10 to the distal end of the thrombus during the thrombus extraction process, and after the cutting stent 10 is delivered to the intended position (for example, at the distal end of the thrombus), a pulling force is exerted on the cutting stent 10 to move the cutting stent 10 within the blood vessel to scrape the thrombus.

[0036] Please refer to FIGS. 5 and 6, the cutting stent 10 includes a first stent A and a second stent B connected in series in the axial direction. The first stent A is located at the proximal end of the second stent B, and both the first stent A and the second stent B are part of a mesh structure and both include a plurality of mesh cells 12. The circumferential closed edge of the proximal end of the first stent A forms the cutting portion 11. The first stent A and the second stent B are connected and jointly form the inner cavity of the cutting stent 10.

[0037] Please refer to FIGS. 5 and 6, the first stent A includes a first axial interval segment A1 and a second axial interval segment A2 connected in series from proximal to distal. It should be noted that when a mesh cell 12 is formed by a portion of the cutting portion 11 and other support rods 121 jointly enclosing the portion, the portion of the cutting portion 11 forming the mesh cell 12 can also be referred to as a support rod 121.

[0038] Please refer to FIGS. 5 and 6, the first axial interval segment A1 is an axial interval segment where the cutting portion 11 is located, and the axial length of the first axial interval segment A1 is equal to the axial length of the cutting portion 11. The proximal end of the second axial interval segment A2 is connected to the first axial interval segment A1.

[0039] Please refer to FIGS. 6 and 7A, when the first stent A is unfolded to be in a planar state, the first axial interval segment A1 is substantially in the shape of an isosceles triangle. The first axial interval segment A1 includes a sharp corner portion at the proximal end and a wave-shaped portion (not labeled in the figure) at the distal end. Among them, the sharp corner portion is the proximal end 112 of the cutting portion 11, and the distal end of the two legs of the isosceles triangle is closed to form the distal end 111 of the cutting portion 11. It should be noted that the above-mentioned "unfolded to be in a planar state" refers to the state of the cutting stent 10 being unfolded to be in a planar state after being cut from the distal end 111 along the axial direction of the cutting stent 10, and when the cutting stent 10 is in the "unfolded to be in a planar state", the first stent A is also necessarily in the "unfolded to be in a planar state".

[0040] Please refer to FIGS. 6 and 7A, the second axial interval segment A2 is in the shape of a cylinder and has a cylindrical inner cavity with two open ends. The distal end of the second axial interval segment A2 is connected to the proximal end of the second stent B. The end of the second axial interval segment A2 away from the second stent B is connected to the first axial interval segment A1.

[0041] In the process of operating the thrombus extraction device 1 to extract the thrombus, the cutting part 11 of the cutting stent 10 is first located at the distal end of the thrombus, and then the binding force acting on the cutting stent 10 is removed, so that the cutting stent 10 self-expands to make the cutting part 11 adhere to the blood vessel wall. Since the cutting part 11 is a circumferentially closed structure, the cutting part 11 can adhere to the blood vessel wall in the circumferential direction of 360°. A pulling force is applied to the push-pull tube 20 to drive the cutting stent 10 to move towards the proximal end, so as to cut the thrombus on the blood vessel wall. The thrombus cut off by the cutting part 11 enters the inner cavity of the cutting stent 10 through the cutting part 11 and is captured, so as to be taken out of the body by the cutting stent 10.

[0042] Please refer to FIG. 7A, the first stent A of the embodiment includes a first extension area 14 (please refer to FIG. 7A and FIG. 7B), a second extension area 15 (please refer to FIG. 7A and FIG. 7C), a third extension area 16 (please refer to FIG. 7A and FIG. 7D) and a fourth extension area 17 (please refer to FIG. 7A and FIG. 7C) extending in the axial direction, and the first extension area 14, the second extension area 15, the third extension area 16 and the fourth extension area 17 are sequentially arranged and connected in the circumferential direction (the circumferential direction of the three-dimensional structure, not the planar unfolded diagram). The first extension area 14 is radially opposite to the third extension area 16. The second extension area 15 is radially opposite to the fourth extension area 17. The cutting part 11 (the state of the cutting part 11 unfolded in the planar state can be referred to FIG. 7A and FIG. 7E) is connected to the proximal end of the first extension area 14, the second extension area 15, the third extension area 16 and the fourth extension area 17. The first extension area 14, the second extension area 15, the third extension area 16 and the fourth extension area 17 take the support rod 121 of the cutting part 11 as the boundary of the proximal end, but the support rod 121 of the cutting part 11 does not belong to the support rod 121 in the first extension area 14, the second extension area 15, the third extension area 16 and the fourth extension area 17, that is, the cutting part 11 is located outside the first extension area 14, the second extension area 15, the third extension area 16 and the fourth extension area 17. The distal end 111 of the cutting part 11 is adjacent to the proximal end of the first extension area 14, and the proximal end 112 of the cutting part 11 is adjacent to the proximal end of the third extension area 16.

[0043] The hardness of the first extension area 14 is greater than the hardness of the second extension area 15, the hardness of the first extension area 14 is greater than the hardness of the fourth extension area 17, the hardness of the third extension area 16 is greater than the hardness of the second extension area 15, and the hardness of the third extension area 16 is greater than the hardness of the fourth extension area 17.

[0044] The first extension region 14 is directly or indirectly connected with the second extension region 15, and the first extension region 14 is directly or indirectly connected with the fourth extension region 17. When the first extension region 14 is indirectly connected with the second extension region 15, there is a transition region between the first extension region 14 and the second extension region 15, and the hardness of the transition region is between the hardness of the first extension region 14 and the hardness of the second extension region 15. When the first extension region 14 is indirectly connected with the fourth extension region 17, there is a transition region between the first extension region 14 and the fourth extension region 17, and the hardness of the transition region is between the hardness of the first extension region 14 and the hardness of the fourth extension region 17.

[0045] When the cutting stent 10 is used to perform thrombectomy, because the hardness of the first extension region 14 is greater than the hardness of the second extension region 15 and the fourth extension region 17, when the cutting stent 10 gradually enters the blood vessel with a smaller inner diameter, the support rods 121 in the second extension region 15 and the fourth extension region 17 are circumferentially deformed to a greater extent than the support rods 121 in the first extension region 14, thereby reducing or avoiding excessive accumulation of the support rods 121 in the first extension region 14, and because the distal end 111 of the cutting portion 11 is adjacent to the proximal end of the first extension region 14, reducing or avoiding excessive accumulation of the support rods 121 in the first extension region 14 can reduce or avoid the support rods 121 near the distal end 111 of the cutting portion 11 from being folded inward due to excessive accumulation, thereby facilitating improved apposition of the cutting portion 11 in the blood vessel.

[0046] In addition, the hardness of the third extension region 16 is greater than the hardness of the second extension region 15, and the hardness of the third extension region 16 is greater than the hardness of the fourth extension region 17, so that the third extension region 16 can have a relatively high hardness, thereby enabling the third extension region 16 to have a relatively high axial tensile strength. When the cutting stent 10 is driven by the push-pull tube 20 to move in the blood vessel, the extent to which the third extension region 16 is axially elongated can be reduced, thereby reducing the extent to which the cutting portion 11 is deformed inward due to axial elongation, thereby avoiding causing the cutting portion 11 to separate from the blood vessel wall. Therefore, the hardness of the first extension region 14 is greater than the hardness of the second extension region 15, the hardness of the first extension region 14 is greater than the hardness of the fourth extension region 17, the hardness of the third extension region 16 is greater than the hardness of the second extension region 15, and the hardness of the third extension region 16 is greater than the hardness of the fourth extension region 17, which can reduce the extent to which the cutting portion 11 is axially elongated while avoiding excessive accumulation of the support rods 121 near the distal end 111 of the cutting portion 11, thereby increasing the apposition of the cutting portion 11.

[0047] The rigidity of each region can be achieved by setting the rod width of the support rods 121 in each region. In other conditions being the same, the wider the rod width of the support rods 121 in a region, the greater the rigidity of the region, and vice versa.

[0048] In an embodiment, the rod width of the support rods 121 in the first extension region 14 is greater than the rod width of the support rods 121 in the second extension region 15 and the fourth extension region 17, so that the rigidity of the first extension region 14 is greater than the rigidity of the second extension region 15, and the rigidity of the first extension region 14 is greater than the rigidity of the fourth extension region 17, to avoid excessive concentration of the support rods 121 at the distal end 111 during the process of the cutting stent 10 entering a blood vessel with a smaller inner diameter.

[0049] In an embodiment, the rod width of the support rods 121 in the third extension region 16 is greater than the rod width of the support rods 121 in the second extension region 15 and the fourth extension region 17, so that the rigidity of the third extension region 16 is greater than the rigidity of the second extension region 15, and the rigidity of the third extension region 16 is greater than the rigidity of the fourth extension region 17, and thus the support strength of the third extension region 16 is greater than the support strength of the second extension region 15 and the fourth extension region 17, so as to reduce the inwardly shrinking deformation due to the axial elongation of the cutting portion 11, thereby avoiding the cutting portion 11 from being separated from the blood vessel wall.

[0050] The third extension region 16 is directly or indirectly connected to the second extension region 15, and the first extension region 14 is directly or indirectly connected to the fourth extension region 17. When the third extension region 16 is indirectly connected to the second extension region 15, there is a transition region between the third extension region 16 and the second extension region 15, and the rigidity of the transition region is between the rigidity of the third extension region 16 and the rigidity of the second extension region 15.

[0051] In an embodiment, the rigidity of the third extension region 16 is the same as the rigidity of the first extension region 14.

[0052] In the embodiment shown in FIG. 7A, in a three-dimensional state, the second extension region 15 and the fourth extension region 17 are arranged in a radial direction opposite to each other, and the rigidity of the second extension region 15 and the fourth extension region 17 is equal, so that when the cutting stent 10 enters a blood vessel with a smaller inner diameter, the second extension region 15 and the fourth extension region 17 can have the same or substantially the same circumferential shrinking amplitude, thereby avoiding the cutting stent 10 from being offset to the side (e.g., the side in the circumferential direction of the second extension region 15 or the fourth extension region 17) with a greater shrinking amplitude, and thus avoiding the cutting portion 11 from being driven to synchronously offset and separated from the blood vessel wall.

[0053] Please refer to FIG. 6, the second stent B is tapered, the smaller diameter end of the second stent B is located at the distal end, and the larger diameter end is located at the proximal end. The larger diameter end of the second stent B is connected to the distal end of the second axial interval segment A2. The radial dimension of the second stent B gradually decreases from the proximal end to the distal end. The radial dimension of the second stent B, except for the part connected to the first stent A, is smaller than the radial dimension of the first stent A. The second stent B has a tapered inner cavity, and the larger diameter end of the second stent B is an open end, and the smaller diameter end is a closed end. The closed end is the closed end of the cutting stent 10.

[0054] When the cutting stent 10 is driven to move proximally in the blood vessel to remove the thrombus, because the second stent B is tapered, the radial dimension of the second stent B gradually decreases from the proximal end to the distal end, and the radial dimension of the second stent B, except for the part connected to the first stent A, is smaller than the radial dimension of the first stent A, therefore the radial outward extrusion force of the second stent B on the blood vessel wall is smaller than the radial outward extrusion force of the first stent A on the blood vessel wall, which is beneficial to reduce the resistance between the cutting stent 10 and the inner wall of the blood vessel, and thus the driving force required to drive the cutting stent 10 to move in the blood vessel is smaller. The smaller driving force causes the first axial interval segment A1 to be stretched to a smaller extent, thereby improving the adhesion of the cutting part 11.

[0055] Please refer to FIG. 6 and FIG. 7A, the distal end of the third extension region 16 extends to the vicinity of the boundary between the first stent A and the second stent B. The support rod 121 at the distal end of the third extension region 16 is directly connected to the support rod 121 of the first stent A directly connected to the second stent B, so that the axial length of the third extension region 16 is close to the axial length of the first stent A. The closer the axial length of the third extension region 16 with greater hardness to the axial length of the first stent A, the more beneficial to improve the overall axial tensile performance of the first stent A, thereby improving the adhesion of the cutting part 11.

[0056] Please refer to FIG. 7A, FIG. 7C and FIG. 7D, in an embodiment, the second extension region 15 and the fourth extension region 17 each include a plurality of first extension rods 122 and a plurality of second extension rods 123. Each first extension rod 122 is formed by a plurality of support rods 121, and each second extension rod 122 is formed by at least one support rod 121.

[0057] The proximal end of the first extension rod 122 is closer to the straight line L passing through the proximal end 112 of the cutting portion 11 and the distal end 181 of the cutting support 10 than the distal end of the first extension rod 122, the distal end of the second extension rod 123 is closer to the straight line L passing through the proximal end 112 of the cutting portion 11 and the distal end 181 of the cutting support 10 than the proximal end of the second extension rod 123, and a part of the proximal end of the second extension rod 123 abuts against the cutting portion 11, and the distal end of the second extension rod 123 abutting against the cutting portion 11 abuts against the support rod 121 in the third extension area 16, and the support effect of the second extension rod 123 on the cutting portion 11 is better than the support effect of the first extension rod 122 on the cutting portion 11.

[0058] In an embodiment, the rod width of the second extension rod 123 is set to be greater than the rod width of the first extension rod 122, so that the support strength of the second extension rod 123 is greater than the support strength of the first extension rod 122, and when the cutting support 10 enters a blood vessel with a small inner diameter, the second extension rod 123 can provide relatively large proximal end pointing support force for the cutting portion 11, which is conducive to resisting the distal end pointing resistance of the blood vessel on the cutting portion 11, thereby reducing the gathering of the support rods 121 in the axial interval segment of the cutting portion 11 to the distal end, thereby reducing the degree of axial elongation of the cutting portion 11 and avoiding the accumulation of the support rods 121 near the distal end 111 of the cutting portion 11, thereby improving the wall adhesion of the cutting portion 11. And a part of the proximal end of the second extension rod 123 abuts against the cutting portion 11, and the distal end of the second extension rod 123 abuts against the support rod 121 in the third extension area 16, so the third extension area 16 is equivalent to the support base of the second extension rod 123 abutting against the cutting portion 11, and the hardness of the third extension area 16 is set to be greater than the hardness of the second extension area 15, and the hardness of the third extension area 16 is set to be greater than the hardness of the fourth extension area 17, so that the second extension rod 123 can be stably supported, thereby facilitating the second extension rod 123 to provide support for the cutting portion 11 to reduce the possibility of the cutting portion 11 separating from the inner wall of the blood vessel during the thrombus removal process.

[0059] Although the greater the hardness of the first support A as a whole, the better the cutting portion 11 can adhere to the inner wall of the blood vessel, but since the cutting support 10 needs to pass through the curved blood vessel during the thrombus removal process, if the hardness of the first support A is too large, it will cause the radial outward extrusion force of the first support A on the inner wall of the blood vessel to be too large, thereby causing the cutting support A to be too large. stimulation to the inner wall of the blood vessel. And the hardness of the first support A is too large, which is not conducive to the cutting support 10 passing through the curved blood vessel.

[0060] Please refer to FIG. 7A and FIG. 7C, in an embodiment, the first extension rods 122 and the second extension rods 123 located at the distal end of the first extension region 14. The first extension rods 122 located at the distal end of the first extension region 14 in the second extension region 15 and the fourth extension region 17 are radially opposite to each other, and the distal ends of the two first extension rods 122 are connected. The second extension rods 123 located at the distal end of the first extension region 14 in the second extension region 15 and the fourth extension region 17 are radially opposite to each other, and the distal ends of the two second extension rods 123 are connected. In this way, the interval between the distal end of the first extension region 14 and the distal end of the second axial interval A2 has greater flexibility than the axial interval where the first extension region 14 is located, thereby reducing the stimulation of the interval between the distal end of the first extension region 14 and the distal end of the second axial interval A2 to the inner wall of the blood vessel, and facilitating the cutting stent 10 to pass through the curved blood vessel.

[0061] Please refer to FIG. 8, in an embodiment, the third extension region 16 includes a proximal segment 161 and a distal segment 162 connected to each other. The proximal end of the proximal segment 161 is directly connected to the cutting part 11, and the distal end of the proximal segment 161 is connected to the proximal end of the distal segment 162. In FIG. 8, the proximal segment 161 and the distal segment 162 are divided by a dashed line X. The maximum width of the proximal segment 161 in the circumferential direction is greater than the maximum width of the distal segment 162 in the circumferential direction.

[0062] Since the number of support rods 121 gradually increases in the first axial interval A1 from the proximal end to the distal end, the axial tensile strength of the first axial interval A1 gradually increases from the proximal end to the distal end, so the axial tensile strength of the area closer to the proximal end 112 of the first axial interval A1 is weaker. Therefore, when the area of the region with higher hardness of the cutting stent 10 is constant, the region with higher hardness of the cutting stent 10 closer to the proximal end 112 in the axial direction is more conducive to improving the overall axial tensile strength of the first axial interval A1; when the axial relative position of the region with higher hardness to the proximal end 112 is constant, the larger the area of the region with higher hardness is, the more conducive to improving the overall axial tensile strength of the first axial interval A1.

[0063] The proximal end of the proximal segment 161 of the embodiment is directly connected to the cutting part 11, the maximum width of the proximal segment 161 in the circumferential direction is greater than the maximum width of the distal segment 162 in the circumferential direction, and the hardness of the proximal segment 161 of the third extension region 16 is greater than the hardness of the second extension region 15 and the fourth extension region 17, which is conducive to improving the hardness of the area close to the proximal end 112 in the axial direction, and is conducive to increasing the area of the region with higher hardness close to the proximal end 112, thereby improving the axial tensile strength of the first axial interval A1, and further improving the wall adhesion of the cutting part 11.

[0064] Please continue to refer to FIG. 8, in an embodiment, the support rod 121 at the maximum circumferential width of the proximal segment 161 is directly connected with the support rod 121 of the cutting section 11. Compared with the support rod 121 in the second extension zone 15 and the fourth extension zone 17, the support rod 121 in the proximal segment 161 is harder, and the support rod 121 at the maximum circumferential width of the proximal segment 161 is directly connected with the support rod 121 of the cutting section 11, which is conducive to improving the radial support of the cutting section 11, thereby improving the wall-adhesion of the cutting section 11.

[0065] The support strength of the support rod 121 of the cutting section 11 is greater than the support strength of the first extension rod 122, and the support strength of the support rod 121 of the cutting section 11 is greater than the support strength of the second extension rod 123. For example, by setting the rod width of the support rod 121 of the cutting section 11 to be greater than the rod width of the first extension rod 122 and the second extension rod 123, the support strength of the support rod 121 of the cutting section 11 is greater than the support strength of the first extension rod 122 and the second extension rod 123, which can improve the radial support force of the cutting section 11, thereby improving the wall-adhesion of the cutting section 11.

[0066] Please refer to FIG. 3 and FIG. 4, the thrombus extraction device 1 further comprises an inner tube 60. The inner tube 60 is slidably arranged in the push-pull tube 20, and the distal end of the inner tube 60 protrudes from the distal end of the push-pull tube 20 to be fixedly connected with the distal end of the second stent B. By applying a driving force to the inner tube 60 to make the inner tube 60 slide relative to the push-pull tube 20 to the distal end, the inner tube 60 and the push-pull tube 20 cooperate to jointly apply an axial pulling force to both ends of the cutting stent 10, thereby reducing the radial size of the cutting stent 10.

[0067] Please refer to FIG. 3 and FIG. 4, the thrombus extraction device 1 further comprises a filter membrane 70, which is located in the inner cavity of the cutting stent 10. The filter membrane 70 has a bag-like structure with an open part 71 at the proximal end and a closed end at the distal end. The open part 71 is fixedly connected (for example, fixed by suture sewing) with the distal end of the first stent A (see FIG. 5), and the thrombus scraped off by the cutting section 11 enters the inner cavity of the filter membrane 70 after entering the inner cavity of the cutting stent 10, so as to be intercepted, which can avoid the thrombus from escaping downstream.

[0068] The filter membrane 70 has flexibility, and the part of the filter membrane 70 located in the second stent B can protrude outward under the radial outward extrusion force of the mesh unit 12 of the second stent B.

[0069] After the thrombus scraping is completed, the thrombus collected by the cutting stent 10 needs to be transported to the outside of the body through the delivery channel established by the outer sheath tube for cleaning. By applying an axial pulling force to the cutting stent 10 directed to the outer sheath tube, the cutting stent 10 carrying the thrombus is driven into the inner cavity of the outer sheath tube.

[0070] Please refer to FIG. 3 and FIG. 4, the plug taking device 1 further comprises an intermediate tube 80, which is sleeved on the inner tube 60 in a slidable manner and is located between the push-pull tube 20 and the inner tube 60. The distal end of the intermediate tube 80 is connected with the distal end of the filter membrane 70, and the proximal end of the intermediate tube 80 extends axially and beyond the proximal end of the intermediate tube 80, so as to facilitate the application of a driving force to the intermediate tube 80 to drive the distal end of the filter membrane 70 to move. When it is necessary to adjust the axial position of the distal end of the filter membrane 70, an axial force is applied to the proximal end of the intermediate tube 80, so as to drive the intermediate tube 80 to move axially, and thus the distal end of the filter membrane 70 moves axially under the driving of the intermediate tube 80 between the proximal end position and the distal end position. When the distal end of the filter membrane 70 is driven to the proximal end position, the distal end of the filter membrane 70 is located outside the cutting stent 10, and the inner surface and the outer surface of the filter membrane 70 are reversed to each other, so as to pour out the thrombus in the filter membrane 70; when the distal end of the filter membrane 70 is located at the distal end position, the distal end of the filter membrane 70 is located in the inner cavity of the cutting stent 10 and can intercept the thrombus.

[0071] The technical features of the above embodiments can be combined in any manner. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not contradict each other, they should be considered as falling within the scope of the present disclosure.

[0072] The above only describes the preferred embodiments of the present application, and of course cannot limit the scope of the present application. Therefore, any equivalent changes made according to the claims of the present application shall be considered as falling within the scope of the present application.

Claims

1. A thrombectomy device, comprising: The cutting stent includes a cutting stent with an inner cavity, the cutting stent is a lattice structure with a plurality of lattice units, each of the lattice units includes a plurality of support rods connected end to end, the cutting stent includes a cutting part at the proximal end, the cutting part is an opening communicating with the inner cavity, the cutting part includes a proximal end and a distal end, the cutting stent includes a first extension zone, a second extension zone, a third extension zone and a fourth extension zone extending in the axial direction, the first extension zone, the second extension zone, the third extension zone and the fourth extension zone are sequentially arranged and connected in the circumferential direction, the cutting part is connected to the proximal end of the first extension zone, the second extension zone, the third extension zone and the fourth extension zone, and the distal end of the cutting part is adjacent to the proximal end of the first extension zone, the proximal end of the cutting part is adjacent to the proximal end of the third extension zone, the first extension zone and the third extension zone are radially opposite, the second extension zone and the fourth extension zone are radially opposite, the hardness of the first extension zone is greater than the hardness of the second extension zone, the hardness of the first extension zone is greater than the hardness of the fourth extension zone, the hardness of the third extension zone is greater than the hardness of the second extension zone, and the hardness of the third extension zone is greater than the hardness of the fourth extension zone.

2. The thrombectomy device of claim 1, wherein, The third extension zone includes a proximal segment and a distal segment connected, the proximal end of the proximal segment is directly connected to the cutting part, the distal end of the proximal segment is connected to the proximal end of the distal segment, and the maximum width of the proximal segment in the circumferential direction is greater than the maximum width of the distal segment in the circumferential direction.

3. The thrombectomy device of claim 2, wherein, The support rods at the maximum width of the proximal segment in the circumferential direction are directly connected to the cutting part.

4. The thrombectomy device of claim 1, wherein, The rod width of the support rods in the first extension zone is greater than the rod width of the support rods in the second extension zone, and the rod width of the support rods in the first extension zone is greater than the rod width of the support rods in the fourth extension zone; the rod width of the support rods in the third extension zone is greater than the rod width of the support rods in the second extension zone, and the rod width of the support rods in the third extension zone is greater than the rod width of the support rods in the fourth extension zone.

5. The thrombectomy device of claim 1, wherein, The hardness of the second extension zone and the fourth extension zone is the same.

6. The device according to claim 4 or 5, wherein The second extension zone and the fourth extension zone each include a plurality of first extension rods and a plurality of second extension rods, each of the first extension rods is formed by a plurality of support rods connected, and each of the second extension rods is formed by at least one support rod, the proximal end of the first extension rod is closer to a straight line passing through the proximal end of the cutting part and the distal end of the cutting stent than the distal end, the distal end of the second extension rod is closer to the straight line than the proximal end, the proximal end of part of the second extension rod abuts against the cutting part, the distal end of the second extension rod abutting against the cutting part abuts against the support rods in the third extension zone, and the support strength of the second extension rod is greater than the support strength of the first extension rod.

7. The device of claim 6, wherein the distal end of the elongate member is configured to be inserted into the lumen of the vessel. Part of the first extension rods and part of the second extension rods are located distal to the first extension region, the first extension rods located distal to the first extension region in the second extension region and the fourth extension region are diametrically opposed, the distal ends of the diametrically opposed first extension rods are connected, the second extension rods located distal to the first extension region in the second extension region and the fourth extension region are diametrically opposed, the distal ends of the diametrically opposed second extension rods are connected.

8. The thrombectomy device of claim 6, wherein, The support strength of the cutting portion is greater than the support strength of the first extension rods and the second extension rods.

9. The thrombectomy device of claim 1, wherein, The cutting support includes a first support and a second support, the first support and the second support are both part of the grid structure, the first support and the second support are connected and jointly form an inner cavity of the cutting support, a circumferentially closed edge of a proximal end of the first support forms the cutting portion, a distal end of the third extension region extends to a vicinity of a boundary between the first support and the second support, a support rod located distal to the third extension region is directly connected to a support rod of a distal end of the first support which is directly connected to the second support.

10. The thrombectomy device of claim 1, wherein, The cutting support includes a first support and a second support, the first support and the second support are both part of the grid structure, the first support and the second support are connected and jointly form an inner cavity of the cutting support, a circumferentially closed edge of a proximal end of the first support forms the cutting portion, a radial dimension of the second support gradually decreases in a direction from proximal end to distal end, the radial dimension of the second support except for a part connected to the first support is smaller than the radial dimension of the first support.

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