Thrombectomy stent

Abstract

The thrombectomy stent comprises a hollow tubular stent body, the stent body is provided with a near end and a far end, the far end of the stent body is folded, a far-end grid is arranged at the folded position, and an outward protruding structure is arranged on the stent body. The convex structure comprises a first convex structure located in an area between the near end and the far end of the stent main body and a second convex structure located at the far end of the stent main body, and the first convex structure and the second convex structure protrude and extend towards the outer side of the stent main body to form a dual anti-escape structure for preventing thrombus outside the thrombus extraction main body from escaping; the second convex structure is connected to the far-end grid, and the projection of the second convex structure on the stent body is located in the far-end grid.

Description

Technical Field

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

[0002] Mechanical thrombectomy has currently become one of the most important means for treating patients with acute ischemic stroke. Mechanical thrombectomy for treating acute ischemic stroke has the following advantages: 1. Without thrombolytic drugs, thus reducing the risk of intracranial hemorrhage; 2. The treatment time window may be extended, the standard time reaches 8 hours, and some patients with good collateral circulation can reach 2 days; 3. Directly remove thrombus and accelerate vascular recanalization.

[0003] From current research, thrombi can be roughly classified into the following types: 1. White thrombus, mainly composed of many platelet trabeculae aggregated in a coral shape, with many neutrophils adhering to its surface, forming a leukocyte marginal layer, presumably attracted by the chemotactic effect of fibrin degradation products. Between the platelet trabeculae, reticular fibrin is formed due to the action of activated coagulation factors, and a small amount of blood cells are contained in its meshwork. Macroscopically, it appears grayish-white, with a rough and wavy surface, hard in texture, and tightly connected to the blood vessel wall. 2. Red thrombus, macroscopically appears dark red, fresh red thrombus is moist and has a certain elasticity, and old red thrombus becomes dry, brittle, loses elasticity due to water absorption, and is prone to detachment and embolism. 3. Mixed thrombus, showing alternating layers of red and white stripes, or a layered structure of grayish-white and reddish-brown alternating. 4. Hyaline thrombus, mainly composed of fibrin.

[0004] A thrombectomy stent is a medical device for realizing mechanical thrombectomy. Thrombectomy stents are usually made of nitinol materials. After the thrombectomy stent is placed in the blood vessel, the thrombectomy stent will automatically expand, so that the thrombus will enter the inner cavity of the thrombectomy stent and be captured by the thrombectomy stent. By retracting the thrombectomy stent, the thrombus can be removed, and thus the blood vessel can resume smooth blood flow. However, in actual applications, thrombi with relatively complex structures (mainly including white thrombi and hyaline thrombi with longer, larger or harder structures) are often difficult to enter the inner cavity of the thrombectomy stent, but are at least partially located between the outer side of the stent body of the thrombectomy stent and the inner wall of the blood vessel. When the thrombectomy stent is retracted, such thrombi are very easy to fall off from the thrombectomy stent, resulting in unsatisfactory thrombectomy effects. Summary of the Invention

[0005] In view of this, it is necessary to provide a thrombectomy stent that can reduce the occurrence of thrombus detachment when the thrombectomy stent is retracted.

[0006] The present invention provides a thrombus removal stent, comprising a hollow tubular stent body, the stent body having a proximal end and a distal end, the distal end of the stent body being folded and provided with a distal grid at the folded position, and an outward convex structure being provided on the stent body, the outward convex structure comprising a first outward convex structure located in an area between the proximal end and the distal end of the stent body and a second outward convex structure located at the distal end of the stent body, the first outward convex structure and the second outward convex structure protruding and extending toward the outside of the stent body to form a double anti-escape structure for preventing the thrombus outside the thrombus removal body from escaping, the second outward convex structure being connected to the distal grid and a projection of the second outward convex structure on the stent body being located in the distal grid.

[0007] In one embodiment, there are multiple first convex structures and multiple second convex structures, and no two first convex structures or no two second convex structures are connected.

[0008] In one of the embodiments, the first external convex structures are staggered along the circumference of the stent body in the area between the proximal end and the distal end of the stent body, so that the projections of any two adjacent first external convex structures on the axial center line of the stent body do not overlap, and the second external convex structures are evenly arranged at the distal end of the stent body.

[0009] In one embodiment, the first convex structure and the second convex structure each have a first end connected to the stent body and a second end away from the stent body, and the corresponding outer diameter at the second end is greater than the corresponding outer diameter at the first end.

[0010] In one embodiment, a plurality of first grids are provided in the region between the proximal end and the distal end of the stent body, and the first convex structure is connected to the first grids and its projection on the stent body is located in the first grids.

[0011] In one embodiment, the first convex structure includes a first rod segment and a second rod segment, one end of the first rod segment is connected to one end of the second rod segment, and the other end of the first rod segment and the other end of the second rod segment are respectively connected to different parts of the first grid.

[0012] In one embodiment, a three-dimensional space is formed between the first protruding structure and the first grid for embedding a thrombus so as to clamp the thrombus entering the three-dimensional space, and provide a clamping force to the thrombus located outside the stent body to effectively intercept the thrombus.

[0013] In one of the embodiments, a plurality of second grids are further provided in the area between the proximal end and the distal end of the stent body, and the area of ​​the first grid is larger than the area of ​​the second grid to form a larger three-dimensional space.

[0014] In one embodiment, the first grid and the second grid are arranged crosswise in the axial direction of the stent body; alternatively, the first grid and the second grid are arranged crosswise in the circumferential direction of the stent body; alternatively, the first grid and the second grid are arranged crosswise both in the axial direction and in the circumferential direction of the stent body.

[0015] In one embodiment, the second convex structure includes a first rod segment and a second rod segment. One end of the first rod segment is connected to one end of the second rod segment, and the other ends of the first rod segment and the second rod segment are respectively connected to different parts of the distal grid.

[0016] The thrombectomy stent provided by the present invention can play a dual anti - detachment role by providing a first convex structure in the area between the proximal end and the distal end of the stent body and a second convex structure at the distal end of the stent body. When withdrawing the thrombectomy stent, even if the thrombus located outside the stent body escapes from the first convex structure, it can still be intercepted by the second convex structure and thus be captured by the thrombectomy stent. Description of the Drawings

[0017] Figure 1 It is a schematic diagram of the withdrawal of an existing thrombectomy stent in a bifurcated blood vessel; Figure 2 It is a schematic structural diagram of the thrombectomy stent according to an embodiment of the present invention, with the thrombectomy stent in a compressed state; Figure 3 It is a schematic structural diagram of the thrombectomy stent according to an embodiment of the present invention, with the thrombectomy stent in an expanded state; Figure 4 For Figure 3 A schematic diagram of the thrombectomy stent shown being deployed into a plane; Figure 5 For Figure 4 A partial enlarged view at M in Figure 6 It is a schematic structural diagram of the thrombectomy stent according to an embodiment of the present invention; Figure 7 It is a schematic diagram of the thrombectomy stent according to another embodiment of the present invention being deployed into a plane; Figure 8 It is a schematic diagram of the thrombectomy stent according to yet another embodiment of the present invention being deployed into a plane; Figures 9a - 9e It is a schematic structural diagram of the stent body of different embodiments being deployed into a plane; Figure 10 It is a schematic diagram of the partial imaging of the thrombectomy stent according to an embodiment of the present invention; Figure 11 It is a schematic diagram of the overall imaging of the thrombectomy stent according to an embodiment of the present invention; Figure 12 It is a schematic diagram of the thrombectomy process of the thrombectomy stent according to an embodiment of the present invention; Figures 13a - 13c Schematic diagram of a thrombectomy stent capturing different types of thrombi according to an embodiment of the present invention; Figure 14 Schematic diagram of the thrombectomy stent being retracted through a bifurcated blood vessel according to an embodiment of the present invention.

[0018] Reference numerals: 10, stent body; 101, proximal end; 102, distal end; 110, rod body; 111, first grid; 112, second grid; 20, convex structure; 20a, first convex structure; 20b, second convex structure; 21, main rod portion; 211, first rod segment; 2111, first line; 212, second rod segment; 2121, second line; 2101, first end; 2102, second end; 22, auxiliary rod portion; 221, third rod segment; 222, fourth rod segment; 223, connecting rod segment; 23, connecting rod portion; 30, distal protection structure; 31, distal rod; 311, distal grid; 40, proximal imaging structure; 50, distal imaging structure; 60, main body imaging structure; 200, delivery tube; 300, blood vessel; 301, bifurcated blood vessel; 400, thrombus. Detailed implementation manners

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] It should be noted that when an element is referred to as being "provided on" another element, it can be directly provided on the other element or there may also be an intermediate element. When an element is considered to be "disposed on" another element, it can be directly disposed on the other element or there may be an intermediate element at the same time. When an element is considered to be "fixed to" another element, it can be directly fixed to the other element or there may be an intermediate element at the same time.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0022] Please refer to Figure 1As shown, when the existing thrombectomy stent captures the thrombus 400, the thrombus 400 may be located between the outside of the stent body 10' of the thrombectomy stent and the inner wall of the blood vessel 300. When withdrawing the thrombectomy stent, especially when passing through the bifurcated blood vessel 301, the thrombus 400 is very likely to escape into the bifurcated blood vessel 301.

[0023] Please refer to Figure 2 , Figure 3 , Figure 4 and Figure 12 , the present invention provides a thrombectomy stent for thrombus treatment. The thrombectomy stent can be processed from a metal tube. Specifically, the thrombectomy stent can be formed by laser engraving a nitinol tube and heat treatment for shaping, or the thrombectomy stent can also be woven from nitinol wires. The thrombectomy stent has a compressed state with radial contraction and an expanded state with radial expansion. As Figure 2 shown, the thrombectomy stent is in the compressed state, so it is convenient for the thrombectomy stent to move within the delivery tube 200, thereby facilitating the movement of the thrombectomy stent to the location where the thrombus 400 is located. As Figure 3 shown, the thrombectomy stent is in the expanded state. After moving the thrombectomy stent to the location where the thrombus 400 is located, withdraw the delivery tube 200, and the thrombectomy stent will be released and automatically expand into the Figure 3 shown expanded state. In the expanded state, the thrombectomy stent can capture the thrombus 400.

[0024] Please refer to Figure 3, the thrombectomy stent includes a stent body 10 in a hollow tubular shape, and an outwardly protruding structure 20 is provided on the stent body 10. When the thrombectomy stent is in an expanded state, the outwardly protruding structure 20 protrudes and extends from the stent body 10 toward the outside of the stent body 10. During use, a thrombus 400 with a relatively simple structure (a thrombus 400 with a small volume and a short length, hereinafter referred to as a simple thrombus 400) will directly enter the inner cavity of the stent body 10 and be captured by the thrombectomy stent. When encountering a thrombus 400 with a relatively complex structure (a thrombus 400 with a large volume and a long length, hereinafter referred to as a complex thrombus 400), at least a part of the complex thrombus 400 is located between the outside of the stent body 10 and the inner wall of the blood vessel 300. In the prior art, since the thrombectomy stent is not provided with the outwardly protruding structure 20, when the thrombectomy stent is retracted, the complex thrombus 400 is likely to fall off from the thrombectomy stent. In particular, when the thrombectomy stent moves past the bifurcated blood vessel 301, the thrombus 400 is very likely to fall off and escape into the bifurcated blood vessel 301. The thrombectomy stent provided in the present application can intercept the thrombus 400 from the outside of the thrombectomy stent by providing the outwardly protruding structure 20. Thus, even when encountering a complex thrombus 400 that cannot enter the inner cavity of the stent body 10, the outwardly protruding structure 20 can be used to intercept the thrombus 400, so that when the thrombectomy stent is retracted, the situation of the thrombus 400 falling off is reduced. When encountering the bifurcated blood vessel 301, the outwardly protruding structure 20 can firmly hook the thrombus 400 located between the outside of the stent body 10 and the inner wall of the blood vessel 300, so as to effectively prevent the thrombus 400 from escaping into the bifurcated blood vessel 301, as Figure 14 shown, Figure 14 the direction indicated by the arrow in

[0025] Please refer to Figure 2 and Figure 3 , the stent body 10 has a proximal end 101 and a distal end 102. It can be understood that the "proximal end 101" refers to the end for connecting the delivery system, and the "distal end 102" refers to the end away from the delivery system. During the operation, medical staff retract the thrombectomy stent by operating the proximal end 101 of the stent body 10. Specifically, when retracting the thrombectomy stent, the thrombectomy stent moves in the direction of the proximal end 101 of the stent body 10.

[0026] Please refer to Figure 4 and Figure 5, the convex structure 20 includes a main rod portion 21. The main rod portion 21 has a first end 2101 connected to the stent body 10 and a second end 2102 away from the stent body 10. The first end 2101 is closer to the proximal end 101 of the stent body 10 than the second end 2102. Thus, the first end 2101 is connected to the stent body 10, and the second end 2102 protrudes relatively from the stent body 10, that is, the corresponding outer diameter at the second end 2102 is greater than the corresponding outer diameter at the first end 2101. Therefore, when withdrawing the thrombectomy stent, the outer diameter corresponding to the front end (corresponding to the proximal end 101 of the stent body 10) where the thrombectomy stent moves is relatively small, which is beneficial to the smooth withdrawal of the thrombectomy stent.

[0027] Further, as Figure 6 shown, when the thrombectomy stent is in the expanded state, the main rod portion 21 is inclined with respect to the axial center line K of the stent body 10, and the second end 2102 of the main rod portion 21 is bent in a direction away from the stent body 10 ( Figure 6 not shown in the figure). Since when withdrawing the thrombectomy stent, the thrombectomy stent moves along the direction from the distal end 102 to the proximal end 101 of the stent body 10, and the second end 2102 of the main rod portion 21 is bent in a direction away from the stent body 10, the main rod portion 21 can hook the thrombus 400 more firmly during withdrawal, thereby effectively preventing the thrombus 400 from escaping. When the thrombectomy stent passes through the bifurcated blood vessel 301, the thrombus 400 is less likely to escape into the bifurcated blood vessel 301. The bending of the second end 2102 of the main rod portion 21 in a direction away from the stent body 10 makes the thrombectomy stent have a better effect of preventing the thrombus 400 from escaping. Of course, in other embodiments, the second end 2102 of the main rod portion 21 can also be bent in a direction close to the stent body 10. Or, the second end 2102 of the main rod portion 21 is not bent, that is, the main rod portion 21 extends obliquely with respect to the axial center line of the stent body 10 from the first end 2101 to the second end 2102.

[0028] Please refer to Figure 5 , the main rod portion 21 includes a first rod segment 211 and a second rod segment 212. One end of the first rod segment 211 and one end of the second rod segment 212 are connected, and the connection part forms the second end 2102 of the main rod portion 21. The other end of the first rod segment 211 and the other end of the second rod segment 212 are respectively connected to different parts of the stent body 10, and the connection parts form the first end 2101 of the main rod portion 21. Thus, the second end 2102 of the main rod portion 21 is equivalent to forming a bent structure, which can better extend into the thrombus 400 and firmly hook the thrombus 400.

[0029] Optionally, the first rod segment 211 is a straight rod or an arc-shaped rod, with a simple structure and easy to process. Similarly, the second rod segment 212 is a straight rod or an arc-shaped rod, with a simple structure and easy to process.

[0030] Further, the connection between the first rod segment 211 and the second rod segment 212 is a rounded corner structure. The design of the rounded corner structure can prevent the inner wall of the blood vessel 300 from being stabbed at this connection, reducing the damage to the blood vessel 300. Of course, in other embodiments, the connection between the first rod segment 211 and the second rod segment 212 can also be a sharp corner structure.

[0031] Please refer to Figure 5 , the line connecting the two ends of the first rod segment 211 is defined as the first line 2111, the line connecting the two ends of the second rod segment 212 is defined as the second line 2121, an included angle A is formed between the first line 2111 and the second line 2121, and 15° ≤ A ≤ 80°. It can be understood that the "first line 2111" and the "second line 2121" are not physical structures existing on the thrombus extraction stent, but are only names defined for convenience of description. The smaller the included angle A, the more the first rod segment 211 and the second rod segment 212 tend to coincide, which is not conducive to forming a space for clamping the thrombus 400 between the first rod segment 211 and the second rod segment 212; the larger the included angle A, the larger the clamping space between the first rod segment 211 and the second rod segment 212, which is not conducive to intercepting the thrombus 400. In this embodiment, 15° ≤ A ≤ 80°, so that a proper clamping space is formed between the first rod segment 211 and the second rod segment 212, which is conducive to intercepting the thrombus 400.

[0032] The plane where the first rod segment 211 and the second rod segment 212 are located is defined as the first plane, and an included angle B is formed between the axial center line K of the stent body 10 and the first plane, and 15° ≤ B < 90°, as Figure 6 shown. It can be understood that the "first plane" and the "axial center line" are not physical structures existing on the thrombus extraction stent, but are only names defined for convenience of description. If the included angle B is too small, the protruding height of the first rod segment 211 and the second rod segment 212 relative to the stent body 10 is small, which is not conducive to intercepting the thrombus 400. If the included angle B is too large, the designed lengths of the first rod segment 211 and the second rod segment 212 will be limited to a certain extent and cannot be designed too long, and the shorter first rod segment 211 and second rod segment 212 are also not conducive to intercepting the thrombus 400. In this embodiment, 15° ≤ B < 90°, so that the protruding height of the first rod segment 211 and the second rod segment 212 relative to the stent body 10 is moderate, and the first rod segment 211 and the second rod segment 212 can be designed to be of appropriate lengths, thus being conducive to intercepting the thrombus 400.

[0033] In one embodiment, if 15° ≤ A ≤ 80° and 15° ≤ B < 90°, a three-dimensional space of appropriate size for the thrombus 400 to embed is formed between the first rod segment 211, the second rod segment 212 and the stent body 10, which is conducive to clamping the thrombus 400 entering the three-dimensional space and can provide a good clamping force to the thrombus 400 located outside the stent body 10, so as to effectively intercept the thrombus 400 and prevent the thrombus 400 from falling off and escaping.

[0034] Please refer to Figure 7 , in one embodiment, the convex structure 20 further includes a secondary rod portion 22. One end of the secondary rod portion 22 is connected to the main rod portion 21, and the other end is suspended. The structure of the secondary rod portion 22 is similar to that of the main rod portion 21, the difference being that the secondary rod portion 22 is connected to the main rod portion 21, while the main rod portion 21 is connected to the stent body 10. Further, the secondary rod portion 22 includes a third rod segment 221 and a fourth rod segment 222. One end of the third rod segment 221 and one end of the fourth rod segment 222 are connected to form a suspended end. The other end of the third rod segment 221 is connected to the first rod segment 211, and the other end of the fourth rod segment 222 is connected to the second rod segment 212. Further, the convex structure 20 further includes a connecting rod segment 223, and the connecting rod segment 223 is connected to the secondary rod portion 22 and the main rod portion 21 to strengthen the structural strength of the convex structure 20 and the ability to capture the thrombus 400. One or more secondary rod portions 22 can be provided on the main rod portion 21. Providing the secondary rod portion 22 can increase the grasping points for the thrombus 400, which is conducive to firmly grasping the thrombus 400 and thus preventing the thrombus 400 from escaping. The secondary rod portion 22 can be provided inside or outside the main rod portion 21, and the present application does not limit this.

[0035] Please refer to Figure 8 , in one embodiment, the convex structure 20 further includes a connecting rod portion 23, and the connecting rod portion 23 connects the stent body 10 and the second end 2102 of the main rod portion 21. Providing the connecting rod portion 23 makes the connection between the convex structure 20 and the stent body 10 more firm, which is more conducive to firmly hooking the thrombus 400 when withdrawing the thrombectomy stent.

[0036] Please refer to Figure 4 , the stent body 10 includes a plurality of meshes, and each mesh can include a plurality of rod bodies 110 connected end to end. The rod body 110 can be a straight rod or a curved rod. In this embodiment, the rod body 110 is a curved rod. In the state of being unfolded into a plane, as Figure 4 shown, each mesh is generally diamond-shaped. Each mesh can include four, six or eight rod bodies 110 connected end to end.

[0037] The mesh includes a first mesh 111 and a second mesh 112. When the thrombectomy stent is in the expanded state, the area of the first mesh 111 is larger than that of the second mesh 112. The second mesh 112 with a smaller area can provide better radial support force, which is beneficial for the stent body 10 to fully expand in the blood vessel 300 and support the blood vessel 300. The first mesh 111 with a larger area can provide a larger thrombus 400 capture space. That is to say, the thrombus 400 is more likely to enter the inner cavity of the stent body 10 from the first mesh 111, so it is easier to capture larger-sized and more complex-structured thrombi 400. Moreover, the first mesh 111 with a larger area can reduce the contact area between the stent body 10 and the inner wall of the blood vessel 300. Further, when the thrombectomy stent is in the expanded state, the area of the first mesh 111 is 2 to 6 times that of the second mesh 112. Preferably, when the thrombectomy stent is in the expanded state, the area of the first mesh 111 is 20 mm 2 ~24 mm 2 , and the area of the second mesh 112 is 5 mm 2 ~6 mm 2 . The first mesh 111 and the second mesh 112 with such areas make the thrombectomy stent easier to capture the thrombus 400 and have better radial support force.

[0038] It can be understood that the first mesh 111 and the second mesh 112 can have various arrangement modes, such as Figure 4 and Figure 9a shown. In one embodiment, the first mesh 111 and the second mesh 112 are arranged crosswise in the axial direction of the stent body 10. Please refer to Figures 9b - 9e , which shows other forms of the stent body 10. In other embodiments, the distribution modes of the first mesh 111 and the second mesh 112 are slightly different from those of the embodiment shown in Figure 9a . As shown in Figure 9d , the first mesh 111 and the second mesh 112 are arranged crosswise in the circumferential direction of the stent body 10. As shown in Figure 9b , 9c and 9e, the first mesh 111 and the second mesh 112 are arranged crosswise both in the axial direction and in the circumferential direction of the stent body 10. The stent bodies 10 of these embodiments can all capture the thrombus 400 well, provide good radial support force, and achieve good thrombus 400 capture effect.

[0039] Please refer to Figure 4, in one embodiment, the convex structure 20 is connected to the first grid 111, and the projection of the convex structure 20 on the stent body 10 is located in the first grid 111. In this way, in the expanded state, the convex structure 20 can intercept the thrombus 400 from the outside, thereby preventing the thrombus 400 that enters the lumen of the stent body 10 from escaping from the first grid 111. Since the projection of the convex structure 20 on the stent body 10 is located in the first grid 111, in the compressed state, the convex structure 20 can be located within the first grid 111, so that it will not protrude relative to the stent body 10 or will not protrude too much height relative to the stent body 10, thus facilitating the delivery of the thrombus removal stent within the delivery tube 200 in the compressed state.

[0040] Please refer to Figure 3 , further, a distal protection structure 30 is provided at the distal end 102 of the stent body 10. The distal protection structure 30 includes a plurality of distal rods 31. One ends of the plurality of distal rods 31 are connected to the second grid 112, and the other ends converge and are connected. That is to say, the distal protection structure 30 is gradually converging from one end connected to the second grid 112 to the other end. Any two adjacent distal rods 31 and the rod body 110 of the second grid 112 connected to the two distal rods 31 enclose a distal grid 311. The distal protection structure 30 can effectively prevent the thrombus 400 that enters the lumen of the stent body 10 from escaping, and has a good effect of capturing the thrombus 400.

[0041] Further, the number of the distal rods 31 can be 4 to 8, and the present invention does not limit this. Further, the angle C between the distal rod 31 and the axial center line K of the stent body 10 is 15° to 45°, as Figure 6 shown. In this way, the plurality of distal rods 31 enclose a distal grid 311 with a suitable size, which can effectively prevent the thrombus 400 from falling off and escaping.

[0042] Please refer to Figure 3 , in one implementation, the convex structure 20 is connected to the distal grid 311, and the projection of the convex structure 20 on the stent body 10 is located in the distal grid 311. In this way, in the expanded state, the convex structure 20 can intercept the thrombus 400 from the outside, thereby preventing the thrombus 400 that enters the lumen of the stent body 10 from escaping from the second grid 112, further enhancing the function of the distal protection structure 30 to prevent the thrombus 400 from escaping. Since the projection of the convex structure 20 on the stent body 10 is located in the distal grid 311, in the compressed state, the convex structure 20 can be located within the distal grid 311, so that it will not protrude relative to the stent body 10 or will not protrude too much height relative to the stent body 10, thus facilitating the delivery of the thrombus removal stent within the delivery tube 200 in the compressed state.

[0043] The convex structure 20 includes a first convex structure 20a disposed in a region between the proximal end 101 and the distal end 102 of the stent body 10. The region between the proximal end 101 and the distal end 102 of the stent body 10 is the main functional region of the stent body 10. During use, the main functional region of the stent body 10 (i.e., the region between the proximal end 101 and the distal end 102 of the stent body 10) is usually extended to the target thrombus 400, such as Figure 3 as shown, the first convex structure 20a is disposed in a region between the proximal end 101 and the distal end 102 of the stent body 10, so that the first convex structure 20a can effectively prevent the target thrombus 400 from escaping, thereby enabling the thrombectomy stent to have a better thrombectomy effect. In this embodiment, the first convex structure 20a is connected to the first mesh 111.

[0044] The stent body 10 is provided with a plurality of first convex structures 20a, and the plurality of first convex structures 20a are arranged along the circumferential direction of the stent body 10. And in the axial direction of the stent body 10, any two adjacent first convex structures 20a are arranged staggeredly. The staggered arrangement means that the projections on the axial center line of the stent body 10 do not coincide. In this way, the situation of the layout outer diameter of the stent body 10 being too large will not occur, so as to avoid damage to the inner wall of the blood vessel 300 when the thrombectomy stent is withdrawn due to the setting of the first convex structure 20a.

[0045] Please refer to Figure 3 , the convex structure 20 further includes a second convex structure 20b disposed at the distal end 102 of the stent body 10. The second convex structure 20b can prevent the thrombus 400 located outside the stent body 10 from falling off and escaping. By setting the second convex structure 20b and the first convex structure 20a in this embodiment, a dual anti-detachment effect can be achieved. When the thrombectomy stent is withdrawn, even if the thrombus 400 located outside the stent body 10 escapes from the first convex structure 20a, it can still be intercepted by the second convex structure 20b and thus captured by the thrombectomy stent. It can be seen that the thrombectomy stent of this embodiment has a better thrombectomy effect. In this embodiment, the second convex structure 20b is connected to the distal mesh 311.

[0046] The stent body 10 is provided with a plurality of second convex structures 20b, and the second convex structures 20b are evenly arranged on the outer side of the stent body 10 in a circumferential manner. In this way, the thrombus 400 located around the outside of the stent body 10 can be intercepted by the second convex structure 20b, so as to effectively prevent the thrombus 400 located outside the thrombectomy stent and scattered at the distal end 102 of the stent body 10 from falling off.

[0047] Please refer to Figure 3The thrombectomy stent further includes a proximal developing structure 40, a distal developing structure 50 and a main developing structure 60. The proximal developing structure 40 is arranged at the proximal end 101 of the stent main body 10, the distal developing structure 50 is arranged at the distal end of the stent main body 10, and the main developing structure 60 is arranged on the area between the proximal end 101 and the distal end 102 of the stent main body 10. The proximal developing structure 40, the distal developing structure 50 and the main developing structure 60 can display the position of the thrombectomy stent in the blood vessel 300, present the overall structure of the thrombectomy stent, and help medical staff perform surgical operations.

[0048] The proximal developing structure 40, the distal developing structure 50 and the main developing structure 60 can all be made of metal materials such as platinum-tungsten alloy, platinum-iridium alloy or tantalum alloy, which can provide good radiopaque linearity and thus have a good developing effect. However, the proximal developing structure 40, the distal developing structure 50 and the main developing structure 60 can also be made of other X-ray opaque materials.

[0049] The proximal end developing structure 40 , the distal end developing structure 50 and the main developing structure 60 can all be spring coils or annular structures.

[0050] The proximal visualization structure 40 can be wound and fixed or welded to the connection between the thrombectomy stent and the delivery system. The proximal visualization structure 40 not only provides visualization, but also serves to connect the delivery system and the thrombectomy stent together.

[0051] The distal developing structure 50 can be wound or welded to the distal rod 31. While providing development, the distal developing structure 50 also serves as the distal protective structure 30, thereby ensuring that the distal end of the distal protective structure 30 is gathered together to prevent the thrombus 400 from falling off and escaping.

[0052] The main body developing structure 60 can be fixed on the rod body 110 of the stent body 10 by winding, welding, bonding or inlaying. Furthermore, a plurality of main body developing structures 60 are provided on the stent body 10, and the projections of the plurality of main body developing structures 60 on the central axis K of the stent body 10 do not overlap. The distance from the main body developing structure 60 to the central axis K of the stent body 10 changes with the change of the expansion degree of the stent body 10. The position and expansion degree of the stent body 10 can be judged by the position of the main body developing structure 60 during development, that is, the position and expansion degree of the thrombus removal stent can be judged, so as to judge whether the thrombus removal stent is fully opened, which is convenient for surgical operation. And because different thrombi have different hardness, the expansion degree of the thrombus removal stent in the thrombus will also be different. Therefore, by observing the expansion degree of the thrombus removal stent, the type of thrombus in the lesion can be judged to a certain extent.

[0053] In addition, if the projections of multiple main body imaging structures 60 on the central axis K of the stent main body 10 coincide, the diameter of the circumference corresponding to the part of the stent main body 10 where the main body imaging structures 60 are provided is larger. Therefore, the force required for the stent retrieval device during the pushing process is greater. In this embodiment, since the projections of the multiple main body imaging structures 60 on the central axis K of the stent main body 10 do not coincide, that is, the multiple main body imaging structures 60 are not concentratedly distributed on the same circumference of the stent main body 10. Therefore, the diameter of the circumference corresponding to the part of the stent main body 10 where the main body imaging structures 60 are provided will not increase significantly compared to the diameter of the circumference corresponding to the part of the stent main body 10 where no main body imaging structures 60 are provided. Therefore, the force required for the stent retrieval device during the pushing process is smaller than that in the case where "the projections of the multiple main body imaging structures 60 on the central axis K of the stent main body 10 coincide", which is beneficial to the pushing and retracting of the stent retrieval device in the delivery tube 200 and the blood vessel 600.

[0054] When the stent main body 10 is in the deployed state, multiple main body imaging structures 60 are arranged on the same cylindrical helix. That is to say, the multiple main body imaging structures 60 are arranged in a spiral manner along the axial direction of the stent main body 10. In this way, when imaging is performed under an imaging device, it has a better imaging effect, and the main body imaging structures 60 can better present the deployment degree and position of the stent main body 10, which is more beneficial for medical staff to judge the deployment degree and position of the stent retrieval device and is more beneficial for the operation of the surgery.

[0055] Please refer to Figure 4 , the distance between two main body imaging structures 60 in the axial direction of the stent main body 10 is defined as the axial spacing X, and the dimension of a single second grid 112 in the axial direction of the stent main body 10 is the second dimension Y. Multiple main body imaging structures 60 with the axial spacing X less than the second dimension Y are divided into a group, and the convex structure 20 is provided between two adjacent groups of main body imaging structures 60 in the axial direction of the stent main body 10. In this embodiment, the first convex structure 20a is provided between two adjacent groups of main body imaging structures 60. Please refer to Figure 10 and Figure 11 shown in the figure, which is a schematic diagram of the imaging of the stent retrieval device. In this way, the position of the first convex structure 20a in the blood vessel 300 can be judged by using the main body imaging structures 60, which is beneficial to extending the first convex structure 20a to the position where the thrombus 400 is located and is beneficial to the smooth progress of the surgery. As Figure 4 shown in the figure, the three main body imaging structures 60 within the elliptical dashed box are a group, and the first convex structure 20a is provided between two adjacent groups of main body imaging structures 60.

[0056] Please refer to Figure 12, the thrombectomy process of the thrombectomy stent provided by the present invention is as follows: There is a thrombus 400 in the blood vessel 300. The delivery tube 200 extends into and passes through the thrombus 400. The thrombectomy stent is delivered to the position where the thrombus 400 is located by using the delivery tube 200. Then, the delivery tube 200 is withdrawn, and the thrombectomy stent is released and expanded into an inflated state. The thrombus 400 gradually enters the inner cavity of the stent body 10. Finally, the delivery tube 200 and the thrombectomy stent are withdrawn simultaneously, and the thrombus 400 is removed by using the stent body 10, the outward convex structure 20, and the distal protection structure 30 together. Finally, the blood resumes normal circulation.

[0057] Please refer to Figures 13a - 13c As shown, the thrombectomy stent provided by the present invention can be used to capture thrombi 400 of different sizes and types. Figure 13a As shown is a common thrombus 400 (such as a red thrombus). During the expansion of the stent body 10, the thrombus 400 enters the inner cavity of the stent body 10 through the first grid 111 and the second grid 112 and is captured. The distal protection structure 30 can prevent the thrombus 400 from escaping from the distal end 102. Figure 13b As shown is a complex thrombus 400 (such as a white thrombus, a mixed thrombus, a hyaline thrombus). During the expansion of the stent body 10, part of the thrombus 400 enters the inner cavity of the stent body 10 while part is located outside the stent body 10. The outward convex structure 20 can intercept the thrombus 400 from the outside. Thus, the thrombectomy stent can be used to capture complex thrombi 400. Figure 13c As shown is a thrombus 400 with a small size, being fragile and easy to fall off (such as a red thrombus). After the thrombus 400 enters the inner cavity of the stent body 10, the distal protection structure 30 can intercept the thrombus 400 to prevent it from escaping. It can be seen that the thrombectomy stent provided by the present invention can be used to capture various types of thrombi 400, especially when capturing complex thrombi 400, the effect is more obvious. For complex thrombi 400 that cannot enter the inner cavity of the stent body 10, the outward convex structure 20 can effectively intercept the thrombus 400 from the outside, thereby reducing the occurrence of the thrombus 400 falling off when withdrawing the thrombectomy stent. As Figure 14 shown, when encountering a bifurcated blood vessel 301, it can effectively prevent the thrombus 400 from escaping into the bifurcated blood vessel 301.

[0058] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0059] Those of ordinary skill in the art should recognize that the above embodiments are merely used to illustrate the present invention and are not intended to limit the present invention. As long as appropriate changes and variations made to the above embodiments fall within the scope of the spirit of the present invention, they fall within the scope of protection required by the present invention.

Claims

1. A thrombus removal stent, comprising a hollow tubular stent body, the stent body having a proximal end and a distal end, the distal end of the stent body being folded and having a distal grid at the folded position, characterized in that: The stent body is provided with convex structures, which include a first convex structure in the area between the proximal end and the distal end of the stent body and a second convex structure at the distal end of the stent body. The first convex structure and the second convex structure protrude and extend towards the outside of the stent body to form a double anti-escape structure for preventing blood clots outside the thrombus extraction body from escaping. The second convex structure is connected to the distal mesh and its projection on the stent body is located in the distal mesh.

2. The thrombectomy stent according to claim 1, wherein, There are multiple first convex structures and multiple second convex structures, and any two first convex structures and any two second convex structures are not connected to each other.

3. The thrombectomy stent according to claim 2, wherein, The first convex structures are arranged staggeredly in the area between the proximal end and the distal end of the stent body along the circumferential direction of the stent body, so that the projections of any two adjacent first convex structures on the axial center line of the stent body do not coincide, and the second convex structures are evenly arranged at the distal end of the stent body.

4. The thrombectomy stent according to claim 1, characterized in that, Both the first convex structure and the second convex structure have a first end connected to the stent body and a second end away from the stent body, and the corresponding outer diameter at the second end is greater than the corresponding outer diameter at the first end.

5. The thrombectomy stent according to claim 1, wherein Several first meshes are provided in the area between the proximal end and the distal end of the stent body. The first convex structure is connected to the first mesh and its projection on the stent body is located in the first mesh.

6. The thrombectomy stent according to claim 5, wherein, The first convex structure includes a first rod segment and a second rod segment. One end of the first rod segment is connected to one end of the second rod segment, and the other ends of the first rod segment and the second rod segment are respectively connected to different parts of the first mesh.

7. The thrombectomy stent according to claim 5, wherein, A three-dimensional space for thrombus embedding is formed between the first convex structure and the first mesh to clamp the thrombus entering the three-dimensional space and provide a clamping force to the thrombus located outside the stent body to effectively intercept the thrombus.

8. The thrombectomy stent according to claim 7, wherein, Several second meshes are also provided in the area between the proximal end and the distal end of the stent body, and the area of the first mesh is larger than that of the first mesh to form a larger three-dimensional space.

9. The thrombectomy stent according to claim 8, characterized in that, The first mesh and the second mesh are arranged crosswise in the axial direction of the stent body; or, the first mesh and the second mesh are arranged crosswise in the circumferential direction of the stent body; or, the first mesh and the second mesh are arranged crosswise in both the axial direction and the circumferential direction of the stent body.

10. The thrombectomy stent according to claim 1, characterized in that, The second convex structure includes a first rod segment and a second rod segment. One end of the first rod segment is connected to one end of the second rod segment, and the other ends of the first rod segment and the second rod segment are respectively connected to different parts of the distal mesh.

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