Thrombectomy stent
By designing a convex structure in the thrombectomy structure to form a three-dimensional space clamping thrombus, the problem of complex thrombus falling off during retraction is solved, and more efficient thrombus capture and preventing escape is achieved.
Patent Information
- Application Number
- CN202510477224.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2021-04-30
- Publication Date
- 2025-07-08
AI Technical Summary
When the existing thrombectomy stent is withdrawn, complex thrombosis is prone to fall off from the outer side of the stent body and the inner wall of the blood vessel, resulting in unsatisfactory thrombectomy effect.
A tamper removal stent is designed, including a stent body with a convex structure. The convex structure forms a three-dimensional space to clamp the thrombus, including the first rod segment and the second rod segment. The connection is designed as an arc-shaped or bent structure with a moderate angle to facilitate firmly clamping the thrombus in an expanded state and prevent falling off.
Effectively intercept and clamp the thrombus to prevent it from escaping into the bifurcated blood vessels during the retracement process, improving the success rate and safety of thrombectomy.
Smart Images
Figure CN120267357A_ABST
Abstract
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, thereby 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 mesh. 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 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. The thrombectomy stent is usually made of nitinol material. 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, and the thrombus can be removed by withdrawing the thrombectomy stent, so that the blood vessel can resume smooth blood flow. However, in practical 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 blood vessel wall. When the thrombectomy stent is withdrawn, such thrombi are very easy to fall off from the thrombectomy stent, resulting in 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 withdrawn.
[0006] The present invention provides a thrombectomy stent, which includes a stent body with a plurality of meshes. The stent body has a radially compressed state and a radially expanded state. An outward convex structure is provided in the area between the proximal end and the distal end of the stent body. The outward 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 stent body. A three-dimensional space for thrombus to embed is formed among the first rod segment, the second rod segment and the stent body to clamp the thrombus entering the three-dimensional space.
[0007] In one embodiment, both the first rod segment and the second rod segment are arc-shaped rods.
[0008] In one embodiment, the connection part of the first rod segment and the second rod segment is a fillet structure.
[0009] In one embodiment, the connection part of the first rod segment and the second rod segment bends towards the direction close to the stent body.
[0010] In one embodiment, the connection part of the first rod segment and the second rod segment forms a bending structure that can hook the thrombus.
[0011] In one embodiment, when the thrombectomy stent is in the expanded state, an included angle A is formed between the connection line of the two ends of the first rod segment and the connection line of the two ends of the second rod segment, where 15° ≤ A ≤ 80°. An included angle B is formed between the plane where the first rod segment and the second rod segment are located and the axial center line of the stent body, where 15° ≤ B < 90°, so that the size of the three-dimensional space formed among the first rod segment, the second rod segment and the stent body is appropriate.
[0012] In one embodiment, a plurality of main body imaging structures are provided in the area between the proximal end and the distal end of the stent body, and the distances from the plurality of main body imaging structures to the central axis K of the stent body change with the change of the expansion degree of the stent body.
[0013] In one embodiment, each mesh includes a plurality of rod bodies connected end to end, and the main body imaging structure is fixed on the rod body.
[0014] In one embodiment, the projections of any two main body imaging structures on the central axis K of the stent body do not coincide, and all the main body imaging structures are arranged on the same cylindrical spiral line.
[0015] In one embodiment, the grid includes a first grid and a second grid. The convex structure is connected to the first grid and its projection on the stent body is located within the first grid. The distance between two body imaging structures in the axial direction of the stent body is defined as the axial spacing. The size of a single second grid in the axial direction of the stent body is the second size. Multiple body imaging structures with an axial spacing smaller than the second size are divided into a group. The convex structure is located between two axially adjacent groups of body imaging structures on the stent body.
[0016] For the thrombectomy stent provided by the present invention, a three-dimensional space for thrombus to embed is formed among the first rod segment, the second rod segment of the convex structure and the stent body, which is beneficial to clamping the thrombus entering this three-dimensional space and can provide a good clamping force for the thrombus located outside the stent body, so as to effectively intercept the thrombus and prevent the thrombus from falling off and escaping. Brief Description of the Drawings
[0017] Figure 1 It is a schematic diagram of the retraction 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, and the thrombectomy stent is in a compressed state; Figure 3 It is a schematic structural diagram of the thrombectomy stent according to an embodiment of the present invention, and the thrombectomy stent is in an expanded state; Figure 4 It is Figure 3 a schematic diagram of the thrombectomy stent shown being deployed into a plane; Figure 5 It is 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 partial imaging schematic diagram of the thrombectomy stent according to an embodiment of the present invention; Figure 11 It is an overall imaging schematic diagram 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 It is a schematic diagram of the thrombectomy stent according to an embodiment of the present invention capturing different types of thrombi; Figure 14 Schematic diagram of the retrieval stent of 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, sub-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 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 1 As shown, when the existing retrieval stent captures the thrombus 400, the thrombus 400 may be located between the outside of the stent body 10' of the retrieval stent and the inner wall of the blood vessel 300. When retracting the retrieval 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 nickel-titanium tube and heat treatment for shaping, or the thrombectomy stent can also be woven from nickel-titanium wires. The thrombectomy stent has a compressed state with radial contraction and an expanded state with radial expansion. As shown in Figure 2 , the thrombectomy stent is in the compressed state, which is convenient for the thrombectomy stent to move within the delivery tube 200, so as to facilitate the movement of the thrombectomy stent to the location where the thrombus 400 is located. As shown in Figure 3 , 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 expanded state shown in Figure 3 . 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 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 from the stent body 10 toward the outside of the stent body 10. In 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 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, 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 also be used to intercept the thrombus 400, so as to reduce 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, so as to effectively prevent the thrombus 400 from escaping into the bifurcated blood vessel 301. As shown in Figure 14 , Figure 14 , the direction indicated by the arrow in
[0025] Please refer to Figure 2 andFigure 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 relative to the stent body 10, that is, the outer diameter corresponding to the second end 2102 is larger than the outer diameter corresponding to 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 is bent 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 is bent in the 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 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 may also be bent in the direction towards 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 5The main rod 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 constitutes the second end 2102 of the main rod 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 constitutes the first end 2101 of the main rod 21. In this way, the second end 2102 of the main rod 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 rod, which has a simple structure and is easy to process. Similarly, the second rod segment 212 is a straight rod or an arc rod, which has a simple structure and is easy to process.
[0030] Furthermore, the connection between the first rod segment 211 and the second rod segment 212 is a rounded structure. The rounded structure design can prevent the connection from piercing the inner wall of the blood vessel 300, thereby reducing 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-angle structure.
[0031] See also 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, the first line 2111 and the second line 2121 form an angle A, 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 removal 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 overlap, which is not conducive to forming a space between the first rod segment 211 and the second rod segment 212 to clamp the thrombus 400; 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 clamping space of appropriate size 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 a 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°. 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°, 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, thereby 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 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, thereby preventing the thrombus 400 from escaping. The secondary rod portion 22 can be provided inside or outside the main rod portion 21, and this 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 provision 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 expanded state, the area of the first mesh 111 is larger than the area 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 expansion 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 the thrombus 400 with a larger size and more complex structure. 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 expanded state, the area of the first mesh 111 is 2 to 6 times the area 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 methods. 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 methods of the first mesh 111 and the second mesh 112 are slightly different from those of the embodiment shown in Figure 9a . As Figure 9dAs shown, the first grid 111 and the second grid 112 are arranged to cross each other 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 to cross each other both in the axial direction and the circumferential direction of the stent body 10. The stent bodies 10 of these embodiments can all capture 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 thrombus 400 from the outside, thereby preventing the thrombus 400 entering the inner cavity of the stent body 10 from escaping outside 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 relative to the stent body 10, thus facilitating the delivery of the thrombus extraction stent within the delivery tube 200 in the compressed state.
[0040] Please refer to Figure 3 . Further, the distal end 102 of the stent body 10 is provided with a distal protection structure 30. 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 the 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 inner cavity of the stent body 10 from escaping, and achieve a good effect of capturing 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° - 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 mesh 311, and the projection of the convex structure 20 on the stent body 10 is located within the distal mesh 311. Thus, in the expanded state, the convex structure 20 can intercept the thrombus 400 from the outside, thereby preventing the thrombus 400 that has entered the lumen of the stent body 10 from escaping outside the second mesh 112, further enhancing the function of the distal protection structure 30 in preventing the thrombus 400 from escaping. If the projection of the convex structure 20 on the stent body 10 is located within the distal mesh 311, then in the compressed state, the convex structure 20 can be located within the distal mesh 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, so that the first convex structure 20a can effectively prevent the target thrombus 400 from escaping, thereby enabling the thrombus retrieval stent to have a better thrombus retrieval effect. In this embodiment, the first convex structure 20a is connected to the first mesh 111.
[0044] A plurality of first convex structures 20a are provided on the stent body 10, 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. Thus, it will not cause the outer diameter of the layout of the stent body 10 to be too large, thereby avoiding damage to the inner wall of the blood vessel 300 when retracting the thrombus retrieval stent due to the setting of the first convex structure 20a.
[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 mesh 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 uniformly 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 and present 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 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 size of a single second grid 112 in the axial direction of the stent main body 10 is the second size Y. A plurality of main body imaging structures 60 with the axial spacing X less than the second size 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 determined 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 is beneficial to the smooth progress of the operation. As Figure 4 shown, the three main body imaging structures 60 within the elliptical dashed 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 retracted, 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 retracted 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 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 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 while part is located outside the stent main body 10. The convex structure 20 can intercept the thrombus 400 from the outside. Thus, the thrombectomy stent can be used to capture complex thrombi 400. Figure 13cShown is a small-sized, fragile and easily detachable thrombus 400 (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, and 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, 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 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 and are not used 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 protection required by the present invention.
Claims
1. A thrombectomy stent, comprising a stent body with a plurality of meshes, the stent body having a radially compressed state and a radially expanded state, characterized in that, An outward convex structure is provided in the area between the proximal end and the distal end of the stent body. The outward 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 stent body. A three-dimensional space for thrombus embedding is formed among the first rod segment, the second rod segment and the stent body to clamp the thrombus entering the three-dimensional space.
2. The thrombectomy stent according to claim 1, wherein Both the first rod segment and the second rod segment are arc-shaped rods.
3. The thrombectomy stent according to claim 1, wherein, The connection part of the first rod segment and the second rod segment is a rounded corner structure.
4. The thrombectomy stent according to claim 1, wherein, The connection part of the first rod segment and the second rod segment is bent towards the direction close to the stent body.
5. The thrombectomy stent according to claim 4, wherein The connection part of the first rod segment and the second rod segment forms a bending structure that can hook the thrombus.
6. The thrombectomy stent according to claim 1, wherein, When the thrombectomy stent is in the expanded state, an included angle A is formed between the connection line of the two ends of the first rod segment and the connection line of the two ends of the second rod segment, where 15° ≤ A ≤ 80°. An included angle B is formed between the plane where the first rod segment and the second rod segment are located and the axial center line of the stent body, where 15° ≤ B < 90°, so that the size of the three-dimensional space formed among the first rod segment, the second rod segment and the stent body is appropriate.
7. The thrombectomy stent according to claim 1, wherein A plurality of main body imaging structures are provided in the area between the proximal end and the distal end of the stent body, and the distances from the plurality of main body imaging structures to the central axis K of the stent body change with the change of the expansion degree of the stent body.
8. The thrombectomy stent according to claim 7, wherein, Each grid includes a plurality of rod bodies connected end to end, and the main body imaging structure is fixed on the rod bodies.
9. The thrombectomy stent according to claim 7, wherein The projections of any two main body imaging structures on the central axis K of the stent body do not coincide, and all the main body imaging structures are arranged on the same cylindrical helix.
10. The thrombectomy stent according to claim 8, wherein, The grid includes a first grid and a second grid. The outward convex structure is connected to the first grid and its projection on the stent body is located in the first grid. The distance between two main body imaging structures in the axial direction of the stent body is defined as the axial pitch. The size of a single second grid in the axial direction of the stent body is the second size. A plurality of main body imaging structures with an axial pitch less than the second size are divided into a group, and the outward convex structure is located between two groups of main body imaging structures adjacent in the axial direction of the stent body.