Thrombectomy stent

Abstract

The thrombectomy stent comprises a stent body with a radial compression state and a radial expansion state, a far-end protection structure is arranged at the far end of the stent body and comprises a plurality of far-end rods, one ends of the far-end rods are connected with the far end of the stent body, and the other ends of the far-end rods are connected in a converging mode. A far-end grid is defined by any two adjacent far-end rods and the far end of the stent body, the far end of the stent body is provided with an outwards-protruding structure, the outwards-protruding structure is connected to the far-end grid, the projection of the outwards-protruding structure on the stent body is located in the far-end grid, and when the thrombectomy stent is in a compressed state, the outwards-protruding structure is located in the far-end grid. When the thrombectomy stent is in an expanded state, the convex structure protrudes and extends from the stent main body to the outer side of the stent main body, so that the convex structure can be utilized to intercept a complicated thrombus which cannot enter an inner cavity of the stent main body.

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 using thrombolytic drugs, thus reducing the risk of intracranial hemorrhage; 2. The treatment time window may be extended, with the standard time reaching 8 hours, and some patients with good collateral circulation can reach 2 days; 3. Directly remove thrombus and accelerate vascular recanalization.

[0003] From the current research, thrombus can be roughly divided 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 mesh. Macroscopically, it appears grayish-white, with a rough and corrugated 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 falling off and causing 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, thrombus with a relatively complex structure (mainly including white thrombus and hyaline thrombus with a relatively long, large or hard structure) often has difficulty entering the inner cavity of the thrombectomy stent, but is at least partially located between the outside of the stent body of the thrombectomy stent and the blood vessel inner wall. When the thrombectomy stent is retracted, such thrombus is very easy to fall off from the thrombectomy stent, resulting in an unsatisfactory thrombectomy effect. 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 stent body with a radial compression state and a radial expansion state, a distal protection structure is provided at the distal end of the stent body, the distal protection structure comprises a plurality of distal rods, one end of the plurality of distal rods is connected to the distal end of the stent body, and the other end is converged and connected, any two adjacent distal rods and the distal end of the stent body form a distal grid, the distal end of the stent body is provided with an outer convex structure, the outer convex structure is connected to the distal grid and the projection on the stent body is located in the distal grid, when the thrombus removal stent is in a compressed state, the outer convex structure is located in the distal grid, and when the thrombus removal stent is in an expanded state, the outer convex structure protrudes and extends from the stent body toward the outside of the stent body.

[0007] In one embodiment, when the thrombectomy stent is in an expanded state, the angle between the distal rod and the axial center line of the stent body is 15° to 45°, so that the distal grid formed between the distal rod and the distal end of the stent body is of appropriate size.

[0008] In one embodiment, the distal rod is gradually contracted from the end connected to the stent body to the end away from the stent body.

[0009] In one of the embodiments, a distal development structure is provided at the retracted portion of the distal rod.

[0010] In one embodiment, the distal development structure is fixed to the distal rod by winding or welding and the distal rod is gathered together.

[0011] In one embodiment, the outer convex structure is provided in plurality, and the plurality of outer convex structures are evenly arranged in a circumferential manner on the outer circumference of the distal end of the stent body.

[0012] In one embodiment, the outer convex structure has a first end connected to the bracket body and a second end away from the bracket body, and the outer diameter corresponding to the second end is greater than the outer diameter corresponding to the first end.

[0013] In one embodiment, the outward convex structure includes a first rod segment and a second rod segment, the proximal end of the first rod segment and the proximal end of the second rod segment are respectively connected to different parts of the distal end of the stent body, and the distal end of the first rod segment and the distal end of the second rod segment are connected and form a rounded corner at the connection.

[0014] In one embodiment, the first rod segment and the second rod segment are connected to the third rod segment and the fourth rod segment, the proximal end of the third rod segment and the proximal end of the fourth rod segment are respectively connected to the first rod segment and the second rod segment, and the distal end of the third rod segment and the distal end of the fourth rod segment are connected to form a suspended end.

[0015] In one embodiment, a connecting rod segment is provided between a connection point between the distal ends of the third rod segment and the fourth rod segment and a connection point between the distal ends of the first rod segment and the second rod segment.

[0016] The thrombectomy stent provided by the present invention has an outward convex structure connected to the distal mesh and its projection on the stent body is located within the distal mesh. Thus, in the compressed state, the outward convex structure is located within the distal mesh, facilitating the delivery of the thrombectomy stent within the delivery tube in the compressed state. In the expanded state, the outward convex structure can intercept thrombus from the outside. Therefore, even when encountering complex thrombus that cannot enter the lumen of the stent body, the outward convex structure can be used to intercept the thrombus. Description of the Drawings

[0017] Figure 1 Schematic diagram of the retraction of an existing thrombectomy stent in a bifurcated blood vessel; Figure 2 Schematic diagram of the structure of the thrombectomy stent according to an embodiment of the present invention, the thrombectomy stent being in a compressed state; Figure 3 Schematic diagram of the structure of the thrombectomy stent according to an embodiment of the present invention, the thrombectomy stent being in an expanded state; Figure 4 For Figure 3 Schematic diagram of the thrombectomy stent shown being unfolded into a plane; Figure 5 For Figure 4 Local enlarged view at M in Figure 6 Schematic diagram of the structure of the thrombectomy stent according to an embodiment of the present invention; Figure 7 Schematic diagram of the thrombectomy stent according to another embodiment of the present invention being unfolded into a plane; Figure 8 Schematic diagram of the thrombectomy stent according to yet another embodiment of the present invention being unfolded into a plane; Figures 9a - 9e Schematic diagram of the structure of the stent body of different embodiments being unfolded into a plane; Figure 10 Partial imaging schematic diagram of the thrombectomy stent according to an embodiment of the present invention; Figure 11 Overall imaging schematic diagram of the thrombectomy stent according to an embodiment of the present invention; Figure 12 Schematic diagram of the thrombectomy process of the thrombectomy stent according to an embodiment of the present invention; Figures 13a - 13c Schematic diagram of the thrombectomy stent according to an embodiment of the present invention capturing different types of thrombus; Figure 14 Schematic diagram of the thrombectomy stent according to an embodiment of the present invention when retracting through a bifurcated blood vessel.

[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] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to 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 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 1 As shown, when the existing thrombus removal stent captures the thrombus 400, the thrombus 400 may be located between the outside of the stent body 10' of the thrombus removal stent and the inner wall of the blood vessel 300. When withdrawing the thrombus removal 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 radially contracted compressed state and a radially expanded expanded state. As Figure 2 shown, the thrombectomy stent is in the compressed state, which facilitates the movement of the thrombectomy stent 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, the delivery tube 200 is withdrawn, and the thrombectomy stent is released and can 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 hollow tubular stent body 10, and an outward convex structure 20 is provided on the stent body 10. When the thrombectomy stent is in the expanded state, the outward convex structure 20 protrudes and extends outward from the stent body 10 towards 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 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 long length, hereinafter referred to as a complex thrombus 400), at least 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, when the thrombectomy stent does not have the outward convex structure 20, when the thrombectomy stent is withdrawn, the complex thrombus 400 is likely to fall off from the thrombectomy stent. In particular, when the thrombectomy stent moves through 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, by providing the outward convex structure 20, can intercept the thrombus 400 from the outside of the thrombectomy stent. Thus, even when encountering a complex thrombus 400 that cannot enter the inner cavity of the stent body 10, the outward convex structure 20 can be used to intercept the thrombus 400, thereby reducing the occurrence of the thrombus 400 falling off when the thrombectomy stent is withdrawn. When encountering the bifurcated blood vessel 301, the outward convex 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, thereby effectively preventing 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 to the delivery system, and the "distal end 102" refers to the end away from the delivery system. During the operation, medical staff withdraw the thrombectomy stent by operating the proximal end 101 of the stent body 10. Specifically, when withdrawing the thrombectomy stent, the thrombectomy stent moves towards 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. In this way, 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 larger than the corresponding outer diameter at the first end 2101. Therefore, when withdrawing the thrombectomy stent, the outer diameter corresponding to the front end of the moving thrombectomy stent (corresponding to the proximal end 101 of the stent body 10) is relatively small, which is beneficial to the smooth withdrawal of the thrombectomy stent.

[0027] Furthermore, 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 bends in the direction away from the stent body 10 ( Figure 6 not shown in the figure). Since the thrombectomy stent moves along the direction from the distal end 102 to the proximal end 101 of the stent body 10 when withdrawing the thrombectomy stent, and the second end 2102 of the main rod portion 21 bends in the direction away from the stent body 10, the main rod portion 21 can hook the thrombus 400 more firmly during withdrawal, so as to effectively prevent 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 the 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 bend in the direction towards the stent body 10. Or, the second end 2102 of the main rod portion 21 does not bend, 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 is connected to one end of the second rod segment 212, and the connection point 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 points form the first end 2101 of the main rod portion 21. In this way, the second end 2102 of the main rod portion 21 is equivalent to 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] Furthermore, 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 point and reduce 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 connection line of the two ends of the first rod segment 211 is defined as the first line 2111, the connection line of the two ends of the second rod segment 212 is defined as the second line 2121, and an 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 the convenience of description. The smaller the 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 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 suitable 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 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 6As 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°. In this way, 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, 15° ≤ A ≤ 80° and 15° ≤ B < 90°. Then, 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 is 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. The connecting rod segment 223 is connected to the secondary rod portion 22 and the main rod portion 21 to enhance 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 grabbing points for the thrombus 400, which is conducive to firmly grasping the thrombus 400, thereby 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 bracket main body 10 and the second end 2102 of the main rod portion 21. The arrangement of the connecting rod portion 23 makes the connection between the convex structure 20 and the bracket main 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 bracket main body 10 includes a plurality of meshes, and each mesh may include a plurality of rod bodies 110 connected end to end. The rod body 110 may 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 may 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 inflated 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 to the full inflation of the bracket main body 10 in the blood vessel 300 and the support of the blood vessel 300. And 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 bracket main body 10 from the first mesh 111, so it is easier to capture larger and more complex-structured thrombi 400. Moreover, the first mesh 111 with a larger area can reduce the contact area between the bracket main body 10 and the inner wall of the blood vessel 300. Further, when the thrombectomy stent is in the inflated 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 inflated 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 manners. 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 bracket main body 10. Please refer to Figures 9b - 9e , which shows other forms of the bracket main body 10. In other embodiments, the distribution manners of the first mesh 111 and the second mesh 112 are slightly different from those of the Figure 9a shown embodiment. As Figure 9dAs shown, the first grid 111 and the second grid 112 are arranged crosswise in the circumferential direction of the stent body 10. As Figure 9b , 9c and as shown in 9e, the first grid 111 and the second grid 112 are arranged crosswise both in the axial direction and 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 supporting force, and achieve a 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 entering the lumen of the stent body 10 from escaping outside the first grid 111. When 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 thrombectomy 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 entering the lumen of the stent body 10 from escaping, and achieve 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 included 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 outside 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 in height relative to the stent body 10, thus facilitating the delivery of the thrombus retrieval stent within the delivery tube 200 in the compressed state.

[0043] The convex structure 20 includes a first convex structure 20a provided in the 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 location of the target thrombus 400. As Figure 3 shown, the first convex structure 20a is provided in the region between the proximal end 101 and the distal end 102 of the stent body 10, enabling the first convex structure 20a to effectively prevent the target thrombus 400 from escaping, thus endowing the thrombus retrieval stent with a better thrombus retrieval effect. In this embodiment, the first convex structure 20a is connected to the first grid 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. In the axial direction of the stent body 10, any two adjacent first convex structures 20a are arranged staggeredly. The staggered arrangement means that their projections on the axial center line of the stent body 10 do not coincide. In this way, the overall outer diameter of the stent body 10 will not be too large, thus avoiding damage to the inner wall of the blood vessel 300 caused by the setting of the first convex structures 20a when retracting the thrombus retrieval stent.

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

[0046] A plurality of second outward convex structures 20b are provided on the stent body 10, and the second outward 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 outward convex structures 20b, thereby effectively preventing 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 3 , the thrombectomy stent further includes a proximal imaging structure 40, a distal imaging structure 50, and a body imaging structure 60. The proximal imaging structure 40 is provided at the proximal end 101 of the stent body 10, the distal imaging structure 50 is provided at the distal end of the stent body 10, and the body imaging structure 60 is provided in the area between the proximal end 101 and the distal end 102 of the stent body 10. Providing the proximal imaging structure 40, the distal imaging structure 50, and the body imaging structure 60 can show the position of the thrombectomy stent in the blood vessel 300, presenting the overall structure of the thrombectomy stent, which is beneficial to helping medical staff perform surgical operations.

[0048] The proximal imaging structure 40, the distal imaging structure 50, and the body imaging structure 60 can all be made of metal materials such as platinum-tungsten alloy, platinum-iridium alloy, or tantalum alloy. These materials can provide good radiopacity and thus have a good imaging effect. However, it is not limited thereto. The proximal imaging structure 40, the distal imaging structure 50, and the body imaging structure 60 can also be made of other materials that are impervious to X-rays.

[0049] The proximal imaging structure 40, the distal imaging structure 50, and the body imaging structure 60 can all be coil springs or circular ring structures.

[0050] The proximal imaging structure 40 can be wound and fixed or welded and fixed at the connection between the thrombectomy stent and the delivery system. While providing imaging, the proximal imaging structure 40 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 the plurality of main body developing structures 60 on the central axis K of the stent body 10 overlap, the diameter of the circumference corresponding to the portion of the stent body 10 where the main body developing structures 60 are provided is larger, and thus the force required for the thrombectomy stent during the pushing process is larger. In this embodiment, since the projections of the plurality of main body developing structures 60 on the central axis K of the stent body 10 do not overlap, that is, the plurality of main body developing structures 60 are not concentrated on the same circumference of the stent body 10, the diameter of the circumference corresponding to the portion of the stent body 10 where the main body developing structures 60 are provided will not increase significantly relative to the diameter of the circumference corresponding to the portion of the stent body 10 where the main body developing structures 60 are not provided, and thus the force required for the thrombectomy stent during the pushing process is smaller than the force required in the case where the projections of the plurality of main body developing structures 60 on the central axis K of the stent body 10 overlap, thereby facilitating the pushing and retraction of the thrombectomy stent in the delivery tube 200 and the blood vessel 600.

[0054] When the stent body 10 is in the expanded state, the plurality of main body developing structures 60 are arranged on the same cylindrical spiral line. That is to say, the plurality of main body developing structures 60 are arranged in a spiral line along the axial direction of the stent body 10. In this way, when developing under the imaging device, it has a better developing effect, and the main body developing structure 60 can better present the expansion degree and position of the stent body 10, so as to be more conducive to the medical staff to judge the expansion degree and position of the thrombectomy stent, and more conducive to the operation of the operation.

[0055] See also Figure 4, the distance between the 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. A plurality of 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 . As shown, it is a development view of the thrombectomy stent. 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 structure 60, which is beneficial to extending the first convex structure 20a to the position where the thrombus 400 is located and beneficial to the smooth progress of the operation. As Figure 4 shown, the three main body imaging structures 60 within the elliptical dotted line frame 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 expanded state. The thrombus 400 gradually enters the inner cavity of the stent main body 10. Finally, the delivery tube 200 and the thrombectomy stent are withdrawn simultaneously, and the thrombus 400 is taken out by using the stent main body 10, the convex structure 20 and the distal protection structure 30 together. Finally, the blood resumes normal flow.

[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 in the figure is a common thrombus 400 (such as a red thrombus). During the expansion of the stent main body 10, the thrombus 400 enters the inner cavity of the stent main 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 in the figure is a complex thrombus 400 (such as a white thrombus, a mixed thrombus, a hyaline thrombus). During the expansion of the stent main body 10, part of the thrombus 400 enters the inner cavity of the stent main body 10 and part is located outside the stent main body 10. The convex structure 20 can intercept the thrombus 400 from the outside. Therefore, the thrombectomy stent can be used to capture complex thrombi 400. Figure 13cShown is a thrombus 400 that is small in size, fragile and easily detachable (such as a red thrombus). After the thrombus 400 enters the lumen of the stent body 10, the distal protection structure 30 can intercept the thrombus 400 to prevent the thrombus 400 from escaping. Thus, 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 lumen of the stent body 10, the convex structure 20 can effectively intercept the thrombus 400 from the outside, so as to reduce the occurrence of thrombus 400 detachment when withdrawing the thrombectomy stent. As Figure 14 shown, it can effectively prevent the thrombus 400 from escaping into the bifurcated blood vessel 301 when encountering a 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 described in this specification.

[0059] Those of ordinary skill in the art of this technology should recognize that the above embodiments are only used to illustrate the present invention, rather than to limit the present invention. As long as it is within the scope of the spirit of the present invention, appropriate changes and variations made to the above embodiments fall within the scope of the present invention claimed.

Claims

1. A thrombectomy stent, comprising a stent body having a radially compressed state and a radially expanded state, a distal protection structure is provided at the distal end of the stent body, the distal protection structure includes a plurality of distal rods, one ends of the plurality of distal rods are connected to the distal end of the stent body, and the other ends are convergently connected, a distal mesh is formed between any two adjacent distal rods and the distal end of the stent body, and it is characterized in that, The distal end of the stent body is provided with an outward convex structure, which is connected to the distal grid and whose projection on the stent body is located in the distal grid. When the thrombus removal stent is in a compressed state, the outward convex structure is located in the distal grid. When the thrombus removal stent is in an expanded state, the outward convex structure protrudes and extends from the stent body toward the outside of the stent body.

2. The thrombectomy stent according to claim 1, wherein When the thrombectomy stent is in an expanded state, the angle between the distal rod and the axial center line of the stent body is 15° to 45°, so that the distal grid formed between the distal rod and the distal end of the stent body is of appropriate size.

3. The thrombectomy stent according to claim 1, characterized in that, The distal rod is gradually contracted from one end connected to the support body to the other end away from the support body.

4. The thrombectomy stent according to claim 3, wherein, A distal developing structure is provided at the retracted portion of the distal rod.

5. The thrombectomy stent according to claim 4, characterized in that, The distal end developing structure is fixed on the distal end rod by winding or welding and the distal end rod is gathered together.

6. The thrombectomy stent according to claim 1, wherein, There are multiple external convex structures, and the multiple external convex structures are evenly arranged in a circumferential manner on the outer periphery of the distal end of the stent body.

7. The thrombectomy stent according to claim 1, wherein, The outer convex structure has a first end connected to the bracket body and a second end away from the bracket body, and the outer diameter corresponding to the second end is greater than the outer diameter corresponding to the first end.

8. The thrombectomy stent according to claim 1, wherein The protruding structure includes a first rod segment and a second rod segment, wherein the proximal end of the first rod segment and the proximal end of the second rod segment are respectively connected to different parts of the distal end of the stent body, and the distal end of the first rod segment and the distal end of the second rod segment are connected and form a rounded corner at the connection.

9. The thrombectomy stent according to claim 8, wherein The first rod segment and the second rod segment are connected to the third rod segment and the fourth rod segment, the proximal end of the third rod segment and the proximal end of the fourth rod segment are respectively connected to the first rod segment and the second rod segment, and the distal end of the third rod segment and the distal end of the fourth rod segment are connected to form a suspended end.

10. The thrombectomy stent according to claim 9, wherein A connecting rod section is provided between the connection point between the distal ends of the third rod section and the distal ends of the fourth rod section and the connection point between the distal ends of the first rod section and the distal ends of the second rod section.

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