Thrombectomy stent

Abstract

The present invention relates to a thrombus removal stent, comprising a hollow tubular stent body, the stent body is provided with an outer convex structure, the thrombus removal stent has a radially contracted compressed state and a radially expanded expanded state, and when the thrombus removal stent is in the expanded state, the outer convex structure protrudes and extends from the stent body toward the outside of the stent body. The thrombus removal stent provided in the present application can intercept thrombi from the outside of the thrombus removal stent by providing an outer convex structure, so that even if a complex thrombus that cannot enter the inner cavity of the stent body is encountered, the thrombus can be intercepted by the outer convex structure, so that when the thrombus removal stent is withdrawn, the occurrence of thrombus shedding is reduced, and when a bifurcated blood vessel is encountered, the thrombus can be effectively prevented from escaping into the bifurcated blood vessel.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a thrombus removal stent. Background Art

[0002] Mechanical thrombectomy has become the most important means of treating acute ischemic stroke. Mechanical thrombectomy has the following advantages in treating acute ischemic stroke: 1. No thrombolytic drugs are needed, thereby 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 compensation can reach 2 days; 3. Directly remove the thrombus and accelerate the recanalization of the blood vessels.

[0003] According to current research, thrombi can be roughly divided into the following types: 1. White thrombus, mainly composed of many platelet trabeculae aggregated in a coral-like shape, with many neutrophils adhering to its surface to form a leukocyte side layer, which is presumably attracted by the chemotaxis of cellulose disintegration products. Due to the action of activated coagulation factors, a mesh of cellulose is formed between the platelet trabeculae, and a small amount of blood cells are contained in the mesh. It is grayish white in appearance, with a rough and wavy surface, hard texture, and tightly connected to the blood vessel wall. 2. Red thrombus, dark red in appearance, fresh red thrombus is moist and has a certain elasticity, while old red thrombus becomes dry, brittle, loses elasticity, and is easy to fall off and cause embolism due to the absorption of water. 3. Mixed thrombus, with layers of red and white stripes, or a layered structure of grayish white and reddish brown alternating. 4. Hyaline thrombus, mainly composed of cellulose.

[0004] A thrombectomy stent is a medical device that achieves mechanical thrombectomy. The thrombectomy stent is usually made of nickel-titanium material. After the thrombectomy stent is placed in a blood vessel, it will automatically expand, so that the thrombus will enter the inner cavity of the thrombectomy stent and be captured by the thrombectomy stent. The thrombus can be removed by withdrawing the thrombectomy stent, so that the blood vessel can restore blood flow. However, in actual applications, thrombi with more complex structures (mainly including white thrombi with longer, larger or harder structures and transparent thrombi) are often difficult to enter the inner cavity of the thrombectomy stent, but are at least partially located between the outer side of the stent body of the thrombectomy stent and the inner wall of the blood vessel. When the thrombectomy stent is withdrawn, this type of thrombus can easily fall off 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 thrombus removal stent, comprising a hollow tubular stent body, on which an outward convex structure is provided. The thrombus removal stent has a radially contracted compressed state and a radially expanded expanded state. When the thrombus removal stent is in the expanded state, the outward convex structure protrudes and extends from the stent body toward the outside of the stent body.

[0007] In one embodiment, the stent body has a proximal end and a distal end, and the convex structure includes a main rod portion, the main rod portion has a first end connected to the stent body, and a second end away from the stent body, the first end is closer to the proximal end of the stent body than the second end.

[0008] In one embodiment, when the thrombus removal stent is in an expanded state, the main rod portion is inclined relative to the axial center line of the stent body, and the second end of the main rod portion is bent in a direction away from the stent body.

[0009] In one embodiment, the main rod portion 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 connection constitutes the second end of the main rod portion, and the other end of the first rod segment and the other end of the second rod segment are respectively connected to different parts of the bracket body and the connection constitutes the first end of the main rod portion.

[0010] In one embodiment, the first rod segment is a straight rod or a curved rod; the second rod segment is a straight rod or a curved rod.

[0011] In one embodiment, the connection between the first rod segment and the second rod segment is a rounded structure or a pointed structure.

[0012] In one embodiment, when the thrombus removal stent is in an expanded state, a line connecting two ends of the first rod segment is defined as a first line, a line connecting two ends of the second rod segment is defined as a second line, an angle A is formed between the first line and the second line, and 15°≤A≤80°.

[0013] In one embodiment, when the thrombus removal stent is in an expanded state, the plane where the first rod segment and the second rod segment are located is defined as a first plane, an angle B is formed between the axial center line of the stent body and the first plane, and 15°≤B<90°.

[0014] In one embodiment, the convex structure further includes a secondary rod portion, one end of which is connected to the main rod portion, and the other end of which is suspended.

[0015] In one embodiment, the outer protruding structure further includes a connecting rod portion, and the connecting rod portion connects the bracket body and the second end of the main rod portion.

[0016] In one embodiment, the stent body includes a plurality of grids, each of the grids includes a plurality of rods connected end to end, the grids include a first grid and a second grid, and when the thrombus removal stent is in an expanded state, the area of ​​the first grid is greater than the area of ​​the second grid.

[0017] In one embodiment, the convex structure is connected to the first grid, and a projection of the convex structure on the bracket body is located in the first grid.

[0018] In one embodiment, a distal protection structure is provided at the distal end of the stent body, and the distal protection structure includes a plurality of distal rods, one end of the plurality of distal rods is connected to the second grid, and the other end is converged and connected, and any two adjacent distal rods and the rod bodies of the second grid connected to the two distal rods form a distal grid; the convex structure is connected to the distal grid, and the projection of the convex structure on the stent body is located in the distal grid.

[0019] In one embodiment, the stent body has a proximal end and a distal end, and the protruding structure includes a first protruding structure disposed at a region between the proximal end and the distal end of the stent body.

[0020] In one of the embodiments, a plurality of the first outer convex structures are provided on the bracket body, and the plurality of the first outer convex structures are arranged along the circumference of the bracket body, and in the axial direction of the bracket body, any two adjacent first outer convex structures are staggered.

[0021] In one embodiment, the stent body has a proximal end and a distal end, and the convex structure includes a second convex structure disposed at the distal end of the stent body.

[0022] In one embodiment, a plurality of second convex structures are disposed on the stent body, and the second convex structures are evenly arranged in a circumferential manner on the outer circumference of the distal end of the stent body.

[0023] In one of the embodiments, the thrombus removal stent further includes a main body developing structure, and the main body developing structure is arranged on the area between the proximal end and the distal end of the stent body; the stent body includes a first grid and a second grid, and when the thrombus removal stent is in an expanded state, the area of ​​the first grid is greater than the area of ​​the second grid; the distance between two main body developing structures in the axial direction of the stent body is defined as an axial spacing, and the size of a single second grid in the axial direction of the stent body is a second size; a plurality of main body developing structures with an axial spacing less than the second size are divided into a group, and the convex structure is provided between two adjacent groups of main body developing structures in the axial direction of the stent body.

[0024] The thrombus removal stent provided by the present invention can intercept the thrombus from the outside of the thrombus removal stent by providing an external convex structure. Therefore, even if a complex thrombus is encountered that cannot enter the inner cavity of the stent body, the thrombus can be intercepted by using the external convex structure, thereby reducing the occurrence of thrombus detachment when the thrombus removal stent is withdrawn, and effectively preventing the thrombus from escaping into a bifurcated blood vessel when encountering a bifurcated blood vessel. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of the withdrawal of an existing thrombectomy stent in a bifurcated vessel;

[0026] Figure 2 This is a schematic structural diagram of a thrombus removal stent according to an embodiment of the present invention, wherein the thrombus removal stent is in a compressed state;

[0027] Figure 3 This is a schematic structural diagram of a thrombus removal stent according to an embodiment of the present invention, wherein the thrombus removal stent is in an expanded state;

[0028] Figure 4 for Figure 3 The schematic diagram of the thrombectomy stent being unfolded into a plane;

[0029] Figure 5 for Figure 4 A partial enlarged view of the M in the middle;

[0030] Figure 6 A simplified structural diagram of a thrombus removal stent according to an embodiment of the present invention;

[0031] Figure 7 A schematic diagram of a thrombectomy stent according to another embodiment of the present invention unfolded into a plane;

[0032] Figure 8 A schematic diagram of a thrombus removal stent according to another embodiment of the present invention unfolded into a plane;

[0033] Figure 9a-9e It is a simplified structural diagram of the bracket body of different embodiments unfolded into a plane;

[0034] Fig.10 A partial imaging schematic diagram of a thrombectomy stent according to an embodiment of the present invention;

[0035] Fig.11 This is a schematic diagram of the overall development of the thrombus removal stent according to an embodiment of the present invention;

[0036] Fig.12 A schematic diagram of a thrombus removal process using a thrombus removal stent according to an embodiment of the present invention;

[0037] Figure 13a-Figure 13c A schematic diagram of a thrombus removal stent capturing different types of thrombi according to an embodiment of the present invention;

[0038] Fig.14 This is a schematic diagram of a thrombectomy stent being retracted through a bifurcated vessel according to an embodiment of the present invention.

[0039] 1. The support structure of the present invention is shown in Figure 1. The support structure of the present invention is shown in Figure 1. The support structure of the present invention is shown in Figure 1. The support structure of the present invention is shown in Figure 1. The support structure of the present invention is shown in Figure 1. The support structure of the present invention is shown in Figure 1. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] It should be noted that when an element is referred to as being "provided on" another element, it may be directly provided on the other element or there may be a central element. When an element is considered to be "provided on" another element, it may be directly provided on the other element or there may be a central element at the same time. When an element is considered to be "fixed to" another element, it may be directly fixed to the other element or there may be a central element at the same time.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification 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 related listed items.

[0043] See also Figure 1 As shown, when the existing thrombus retriever captures the thrombus 400, the thrombus 400 may be located between the outer side of the stent body 10' of the thrombus retriever and the inner wall of the blood vessel 300. When the thrombus retriever is withdrawn, especially when passing through the bifurcated blood vessel 301, the thrombus 400 can easily escape into the bifurcated blood vessel 301.

[0044] See also Figure 2 , Figure 3 , Figure 4 and Fig.12 The present invention provides a thrombus removal stent for thrombus treatment. The thrombus removal stent can be made of a metal tube. Specifically, the thrombus removal stent can be made of a nickel-titanium tube by laser engraving and heat treatment, or the thrombus removal stent can be woven from nickel-titanium wire. The thrombus removal stent has a radially contracted compressed state and a radially expanded expanded state. Figure 2 As shown, the thrombus removal stent is in a compressed state, which facilitates the movement of the thrombus removal stent in the delivery tube 200, thereby facilitating the movement of the thrombus removal stent to the location of the thrombus 400. Figure 3 As shown, the thrombus removal stent is in an expanded state. After the thrombus removal stent is moved to the location of the thrombus 400, the delivery tube 200 is withdrawn, and the thrombus removal stent is released and automatically expands into Figure 3 In the expanded state, the thrombus 400 can be captured by the thrombus removal stent.

[0045] See also Figure 3 The thrombus removal stent includes a hollow tubular stent body 10, and an outer convex structure 20 is provided on the stent body 10. When the thrombus removal stent is in an expanded state, the outer convex structure 20 protrudes and extends from the stent body 10 toward the outside of the stent body 10. When in use, a thrombus 400 with a relatively simple structure (a thrombus 400 with a relatively small volume and a relatively short volume, hereinafter referred to as a simple thrombus 400) will directly enter the inner cavity of the stent body 10 and be captured by the thrombus removal stent. When encountering a thrombus 400 with a relatively complex structure (a thrombus 400 with a relatively large volume and a relatively long volume, hereinafter referred to as a complex thrombus 400), the complex thrombus 400 is at least partially located between the outside of the stent body 10 and the inner wall of the blood vessel 300. In the prior art, the thrombus removal stent is not provided with the outer convex structure 20, so when the thrombus removal stent is withdrawn, the complex thrombus 400 is easy to fall off from the thrombus removal stent, especially when the thrombus removal stent moves through the bifurcated blood vessel 301, the thrombus 400 is easy to fall off and escape into the bifurcated blood vessel 301. The thrombus removal stent provided in the present application can intercept the thrombus 400 from the outside of the thrombus removal stent by providing the convex structure 20. Therefore, even if a complex thrombus 400 that cannot enter the inner cavity of the stent body 10 is encountered, the convex structure 20 can be used to intercept the thrombus 400, thereby reducing the thrombus 400 from falling off when the thrombus removal stent is withdrawn. When encountering a bifurcated vessel 301, the convex structure 20 can firmly hook the thrombus 400 located between the outside of the stent body 10 and the inner wall of the vessel 300, thereby effectively preventing the thrombus 400 from escaping into the bifurcated vessel 301. Fig.14 As shown, Fig.14 The direction indicated by the middle arrow is the direction in which the thrombectomy stent moves when it is withdrawn.

[0046] See also Figure 2 and Figure 3 The stent body 10 has a proximal end 101 and a distal end 102. It is understood that the "proximal end 101" refers to an end for connecting to a delivery system, and the "distal end 102" refers to an end away from the delivery system. During surgery, medical personnel operate the proximal end 101 of the stent body 10 to withdraw the thrombectomy stent. Specifically, when withdrawing the thrombectomy stent, the thrombectomy stent moves toward the proximal end 101 of the stent body 10.

[0047] See also Figure 4 and Figure 5 The outer convex structure 20 includes a main rod 21, which has a first end 2101 connected to the stent body 10 and a second end 2102 away from the stent body 10, and 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 is relatively protruding from 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 the thrombus removal stent is withdrawn, the outer diameter corresponding to the front end of the thrombus removal stent (corresponding to the proximal end 101 of the stent body 10) is relatively small, which is conducive to the smooth withdrawal of the thrombus removal stent.

[0048] Furthermore, if Figure 6 As shown, when the thrombus removal stent is in an expanded state, the main rod portion 21 is tilted relative to the axial center line K of the stent body 10, and the second end 2102 of the main rod portion 21 is bent in a direction away from the stent body 10 ( Figure 6 (not shown). Since the thrombus retriever moves in the direction from the distal end 102 of the stent body 10 to the proximal end 101 when the thrombus retriever is withdrawn, the second end 2102 of the main rod 21 bends in the direction away from the stent body 10, and the main rod 21 can more firmly hook the thrombus 400 when withdrawn, thereby effectively preventing the thrombus 400 from escaping. When the thrombus retriever passes through the bifurcated vessel 301, the thrombus 400 is less likely to escape into the bifurcated vessel 301, and the second end 2102 of the main rod 21 bends in the direction away from the stent body 10, so that the thrombus retriever has a better effect of preventing the thrombus 400 from escaping. Of course, in other embodiments, the second end 2102 of the main rod 21 can also be bent in the direction close to the stent body 10. Alternatively, the second end 2102 of the main rod 21 is not bent, that is, the main rod 21 extends obliquely from the first end 2101 to the second end 2102 relative to the axial center line of the stent body 10.

[0049] See also 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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 is understandable that the "first plane" and the "axial centerline" are not physical structures existing on the thrombus removal stent, but are names defined for the convenience of description. If the angle B is too small, the protrusion 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 angle B is too large, the design length of the first rod segment 211 and the second rod segment 212 will be subject to certain restrictions and cannot be designed too long, and the shorter first rod segment 211 and the second rod segment 212 are also not conducive to intercepting the thrombus 400. In this embodiment, 15°≤B<90°, so that the protrusion 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 a suitable length, which is conducive to intercepting the thrombus 400.

[0054] In one embodiment, 15°≤A≤80°, and 15°≤B<90°, a three-dimensional space of appropriate size for the thrombus 400 to be embedded 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 providing a good clamping force for the thrombus 400 located outside the stent body 10, thereby effectively intercepting the thrombus 400 and preventing the thrombus 400 from falling off and escaping.

[0055] See also Figure 7 In one embodiment, the external convex structure 20 further includes a secondary rod portion 22, one end of which 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 the main rod portion 21, except that the secondary rod portion 22 is connected to the main rod portion 21, and 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 external convex structure 20 further includes a connecting rod segment 223, which is connected to the secondary rod portion 22 and the main rod portion 21 to enhance the structural strength of the external convex structure 20 and the ability to capture the thrombus 400. One or more auxiliary rods 22 may be provided on the main rod 21. The auxiliary rods 22 may increase the gripping points of the thrombus 400, which is conducive to gripping the thrombus 400, thereby preventing the thrombus 400 from escaping. The auxiliary rods 22 may be provided inside the main rod 21 or outside the main rod 21, and the present application does not limit this.

[0056] See also Figure 8In one embodiment, the outer convex structure 20 further includes a connecting rod portion 23, and the connecting rod portion 23 connects the stent body 10 and the second end 2102 of the main rod portion 21. The connecting rod portion 23 makes the connection between the outer convex structure 20 and the stent body 10 more secure, which is more conducive to firmly hooking the thrombus 400 when withdrawing the thrombus removal stent.

[0057] See also Figure 4 The support body 10 includes a plurality of grids, each of which may include a plurality of rods 110 connected end to end. The rods 110 may be straight rods or curved rods. In this embodiment, the rods 110 are curved rods. Figure 4 As shown, each grid is roughly diamond-shaped. Each grid may include four, six or eight rods 110 connected end to end.

[0058] The grid includes a first grid 111 and a second grid 112. When the thrombectomy stent is in an expanded state, the area of ​​the first grid 111 is larger than the area of ​​the second grid 112. The second grid 112 with a smaller area can provide better radial support, which is beneficial for the stent body 10 to fully expand in the blood vessel 300 and support the blood vessel 300. The first grid 111 with a larger area can provide a larger space for capturing thrombi 400, that is, thrombi 400 can more easily enter the inner cavity of the stent body 10 from the first grid 111, so that it is easier to capture thrombi 400 with larger sizes and more complex structures. In addition, the first grid 111 with a larger area can reduce the contact area between the stent body 10 and the inner wall of the blood vessel 300. Furthermore, when the thrombectomy stent is in an expanded state, the area of ​​the first grid 111 is 2 to 6 times the area of ​​the second grid 112. Preferably, when the thrombectomy stent is in an expanded state, the area of ​​the first grid 111 is 20 mm 2 ~24mm 2 , the area of ​​the second grid 112 is 5 mm 2 ~6mm 2 The first grid 111 and the second grid 112 of this area make it easier for the thrombus removal stent to capture the thrombus 400 and have better radial supporting force.

[0059] It is understandable that the first grid 111 and the second grid 112 can be arranged in a variety of ways, such as Figure 4 and Figure 9a As shown, in one embodiment, the first grid 111 and the second grid 112 are arranged crosswise in the axial direction of the stent body 10. Figure 9b-9e , illustrating other forms of the bracket body 10. In other embodiments, the distribution of the first grid 111 and the second grid 112 is different from Figure 9a The embodiment shown is slightly different. Figure 9dAs shown, the first grid 111 and the second grid 112 are arranged crosswise in the circumferential direction of the stent body 10. Figure 9b , 9c As shown in FIG9e , the first grid 111 and the second grid 112 are cross-arranged in the axial direction and the circumferential direction of the stent body 10. The stent body 10 of these embodiments can better capture the thrombus 400 and provide better radial support force, thereby achieving better thrombus 400 capture effect.

[0060] See also Figure 4 In one embodiment, the convex structure 20 is connected to the first grid 111, and the projection of the convex structure 20 on the stent body 10 is located in the first grid 111. In this way, in the expanded state, the convex structure 20 can intercept the thrombus 400 from the outside, thereby preventing the thrombus 400 that has entered the inner cavity of the stent body 10 from escaping from the first grid 111. The projection of the convex structure 20 on the stent body 10 is located in the first grid 111, and in the compressed state, the convex structure 20 can be located in 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, thereby facilitating the delivery of the thrombus removal stent in the delivery tube 200 in the compressed state.

[0061] See also Figure 3 Furthermore, the distal end 102 of the stent body 10 is provided with a distal protection structure 30, and the distal protection structure 30 includes a plurality of distal rods 31, one end of the plurality of distal rods 31 is connected to the second grid 112, and the other end is convergently connected. In other words, the distal protection structure 30 is gradually gathered 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 form a distal grid 311. The distal protection structure 30 can effectively prevent the thrombus 400 that has entered the inner cavity of the stent body 10 from escaping, and has a good effect of capturing the thrombus 400.

[0062] Furthermore, the number of the distal rods 31 can be 4 to 8, and the present invention is not limited thereto. Furthermore, the angle C between the distal rods 31 and the axial centerline K of the stent body 10 is 15° to 45°. Figure 6 As shown, in this way, a plurality of distal rods 31 form a distal grid 311 of appropriate size, which can effectively prevent the thrombus 400 from falling off and escaping.

[0063] See also Figure 3In 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 entering the inner cavity of the stent body 10 from escaping from the second grid 112, further improving the role of the distal protection structure 30 in preventing the thrombus 400 from escaping. The projection of the convex structure 20 on the stent body 10 is located in the distal grid 311, and in the compressed state, the convex structure 20 can be located in the distal grid 311, so that it will not protrude relative to the stent body 10 or will not protrude too much relative to the stent body 10, thereby facilitating the delivery of the thrombus removal stent in the delivery tube 200 in the compressed state.

[0064] The convex structure 20 includes a first convex structure 20a disposed at 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 action region of the stent body 10. When in use, the main action region of the stent body 10 (i.e., the region between the proximal end 101 and the distal end 102 of the stent body 10) is usually extended to the target thrombus 400, such as Figure 3 As shown, the first convex structure 20a is disposed in 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 well prevent the target thrombus 400 from escaping, thereby making the thrombus removal stent have a better thrombus removal effect. In this embodiment, the first convex structure 20a is connected to the first grid 111.

[0065] The stent body 10 is provided with a plurality of first external convex structures 20a, and the plurality of first external convex structures 20a are arranged along the circumference of the stent body 10, and any two adjacent first external convex structures 20a are arranged staggered in the axial direction of the stent body 10. The staggered arrangement means that the projections on the axial center line of the stent body 10 do not overlap, so that the layout outer diameter of the stent body 10 will not be too large, thereby preventing the first external convex structures 20a from causing damage to the inner wall of the blood vessel 300 when the thrombectomy stent is withdrawn.

[0066] See also Figure 3, the convex structure 20 also includes a second convex structure 20b disposed at the distal end 102 of the stent body 10. The second convex structure 20b can prevent the thrombus 400 located outside the stent body 10 from falling off and escaping. This embodiment can play a dual anti-falling role by providing the second convex structure 20b and the first convex structure 20a. When the thrombus removal stent is withdrawn, the thrombus 400 located outside the stent body 10 can be intercepted by the second convex structure 20b even if it escapes from the first convex structure 20a, and thus captured by the thrombus removal stent. It can be seen that the thrombus removal stent of this embodiment has a better thrombus removal effect. In this embodiment, the second convex structure 20b is connected to the distal grid 311.

[0067] The stent body 10 is provided with a plurality of second convex structures 20b, and the second convex structures 20b are evenly arranged in a circumferential manner on the outside of the stent body 10. In this way, the thrombus 400 located around the outside of the stent body 10 can be intercepted by the second convex structures 20b, thereby effectively preventing the thrombus 400 located outside the thrombus removal stent and scattered at the distal end 102 of the stent body 10 from falling off.

[0068] See also Figure 3 The thrombectomy stent further includes a proximal developing structure 40, a distal developing structure 50 and a main developing structure 60. The proximal developing structure 40 is arranged at the proximal end 101 of the stent main body 10, the distal developing structure 50 is arranged at the distal end of the stent main body 10, and the main developing structure 60 is arranged on the area between the proximal end 101 and the distal end 102 of the stent main body 10. The proximal developing structure 40, the distal developing structure 50 and the main developing structure 60 can display the position of the thrombectomy stent in the blood vessel 300, present the overall structure of the thrombectomy stent, and help medical staff perform surgical operations.

[0069] The proximal developing structure 40, the distal developing structure 50 and the main developing structure 60 can all be made of metal materials such as platinum-tungsten alloy, platinum-iridium alloy or tantalum alloy, which can provide good radiopaque linearity and thus have a good developing effect. However, the proximal developing structure 40, the distal developing structure 50 and the main developing structure 60 can also be made of other X-ray opaque materials.

[0070] The proximal end developing structure 40 , the distal end developing structure 50 and the main developing structure 60 can all be spring coils or annular structures.

[0071] The proximal visualization structure 40 can be wound and fixed or welded to the connection between the thrombectomy stent and the delivery system. The proximal visualization structure 40 not only provides visualization, but also serves to connect the delivery system and the thrombectomy stent together.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] See also Figure 4, the distance between the two main body developing structures 60 in the axial direction of the bracket body 10 is defined as the axial spacing X, and the size of a single second grid 112 in the axial direction of the bracket body 10 is the second size Y. A plurality of main body developing structures 60 whose axial spacing X is smaller than the second size Y are divided into a group, and the convex structure 20 is arranged between two adjacent groups of main body developing structures 60 in the axial direction of the bracket body 10. In this embodiment, the first convex structure 20a is arranged between two adjacent groups of main body developing structures 60. Please refer to Fig.10 and Fig.11 As shown in FIG. 1 , it is a schematic diagram of the development of the thrombus removal stent. In this way, the main development structure 60 can be used to determine the position of the first convex structure 20a in the blood vessel 300, so as to facilitate the first convex structure 20a to be extended to the position where the thrombus 400 is located, which is conducive to the smooth progress of the operation. Figure 4 As shown, the three main body developing structures 60 in the oval dotted frame form a group, and the first outer protruding structure 20 a is disposed between two adjacent groups of main body developing structures 60 .

[0077] See also Fig.12 The thrombus removal process of the thrombus removal 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, and the thrombus removal stent is delivered to the location of the thrombus 400 by using the delivery tube 200, and then the delivery tube 200 is withdrawn, the thrombus removal stent is released and expanded into an expanded state, and the thrombus 400 gradually enters the inner cavity of the stent body 10, and finally the delivery tube 200 and the thrombus removal stent are withdrawn at the same time, and the thrombus 400 is removed together by using the stent body 10, the outer convex structure 20 and the distal protection structure 30, and finally the blood resumes normal circulation.

[0078] See also Figures 13a-13c As shown, the thrombus retriever stent provided by the present invention can be used to capture thrombi 400 of different sizes and types. Fig.13a Shown is a common thrombus 400 (e.g., a red thrombus). During the expansion of the stent body 10, the thrombus 400 enters the inner cavity of the stent body 10 through the first grid 111 and the second grid 112 and is captured. The distal protection structure 30 can prevent the thrombus 400 from escaping from the distal end 102. Fig.13b Shown is a complex thrombus 400 (such as a white thrombus, a mixed thrombus, a transparent thrombus). During the expansion of the stent body 10, part of the thrombus 400 enters the inner cavity of the stent body 10 and part of it is located outside the stent body 10. The outer convex structure 20 can intercept the thrombus 400 from the outside, so that the thrombus removal stent can be used to capture the complex thrombus 400. Fig.13cThe figure shows a thrombus 400 that is small in size, fragile, and easy to fall off (for example, a red thrombus). After the thrombus 400 enters the inner cavity of the stent body 10, the distal protection structure 30 can intercept the thrombus 400 to prevent the thrombus 400 from escaping. It can be seen that the thrombus removal stent provided by the present invention can be used to capture various types of thrombi 400, especially when capturing complex thrombi 400. For complex thrombi 400 that cannot enter the inner cavity of the stent body 10, the convex structure 20 can be used to effectively intercept the thrombus 400 from the outside, thereby reducing the occurrence of thrombus 400 falling off when the thrombus removal stent is withdrawn. Fig.14 As shown, when encountering a bifurcated vessel 301 , the thrombus 400 can be effectively prevented from escaping into the bifurcated vessel 301 .

[0079] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, 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, they should be considered to be within the scope of this specification.

[0080] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, appropriate changes and modifications to the above embodiments are within the scope of protection claimed by the present invention.

Claims

1. A thrombus removal stent, characterized in that: The invention comprises a hollow tubular stent body, on which an outer convex structure is arranged, and the thrombus removal stent has a radially contracted compressed state and a radially expanded expanded state, and when the thrombus removal stent is in the expanded state, the outer convex structure protrudes and extends from the stent body toward the outside of the stent body; the stent body has a proximal end and a distal end, and the outer convex structure comprises a main rod portion, and the main rod portion has a first end connected to the stent body, and a second end away from the stent body, and the first end is closer to the proximal end of the stent body than the second end; when the thrombus removal stent is in the expanded state, the main rod portion is inclined relative to the axial center line of the stent body, and the main rod portion comprises 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 connection constitutes the second end of the main rod portion, the other end of the first rod segment and the other end of the second rod segment are respectively connected to different parts of the stent body and the connection constitutes the first end of the main rod portion, the corresponding outer diameter at the second end is larger than the corresponding outer diameter at the first end, so as to intercept the thrombus located between the outer side of the stent body and the inner wall of the blood vessel from the outside of the stent body, and the second end is formed into a bent structure, and when encountering a bifurcated blood vessel, the second end hooks the thrombus located between the outer side of the stent body and the inner wall of the blood vessel, thereby preventing the thrombus from escaping into the bifurcated blood vessel; The stent body includes a plurality of grids, each grid includes a plurality of rod bodies connected end to end, 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 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 rod bodies at the distal end of the stent body connected to the two distal rods form a distal grid, the convex structure includes a first convex structure provided in the area between the proximal end and the distal end of the stent body and a second convex structure provided at the distal end of the stent body, the second convex structure is connected to the distal grid and its projection on the stent body is located in the distal grid.

2. The thrombus removal stent according to claim 1, characterized in that: The second end of the main rod portion is bent in a direction away from the bracket body, or the second end of the main rod portion is bent in a direction close to the bracket body.

3. The thrombus removal stent according to claim 1, characterized in that: The first rod segment is a straight rod or a curved rod; the second rod segment is a straight rod or a curved rod.

4. The thrombus removal stent according to claim 1, characterized in that: The connection between the first rod segment and the second rod segment is a rounded structure or a pointed structure.

5. The thrombus removal stent according to claim 1, characterized in that: When the thrombectomy stent is in an expanded state, a line connecting two ends of the first rod segment is defined as a first line, a line connecting two ends of the second rod segment is defined as a second line, an angle A is formed between the first line and the second line, and 15°≤A≤80°.

6. The thrombus removal stent according to claim 1, characterized in that: When the thrombectomy stent is in an expanded state, the plane where the first rod segment and the second rod segment are located is defined as a first plane, an angle B is formed between the axial center line of the stent body and the first plane, and 15°≤B<90°.

7. The thrombus removal stent according to claim 1, characterized in that: The external convex structure also includes a secondary rod portion, one end of which is connected to the main rod portion, and the other end of which is suspended.

8. The thrombus removal stent according to claim 1, characterized in that: The outer protruding structure further includes a connecting rod portion, and the connecting rod portion connects the bracket body and the second end of the main rod portion.

9. The thrombus removal stent according to claim 1, characterized in that: The grid includes a first grid and a second grid. When the thrombus retriever stent is in an expanded state, the area of ​​the first grid is greater than the area of ​​the second grid.

10. The thrombus removal stent according to claim 9, characterized in that: The first convex structure is connected to the first grid, and a projection of the first convex structure on the bracket body is located in the first grid.

11. The thrombus removal stent according to claim 9, characterized in that: Any two adjacent distal rods and the rod bodies of the second grid connected to the two distal rods form a distal grid.

12. The thrombus removal stent according to claim 1, characterized in that: There are a plurality of the first external convex structures, and the plurality of the first external convex structures are arranged along the circumferential direction of the bracket body, and in the axial direction of the bracket body, any two adjacent first external convex structures are staggered.

13. The thrombus removal stent according to claim 1, characterized in that: There are a plurality of second outer protrusion structures, and the second outer protrusion structures are evenly arranged in a circumferential manner on the outer circumference of the distal end of the stent body.

14. The thrombus removal stent according to claim 1, characterized in that: The thrombus removal stent further comprises a main body developing structure, and the main body developing structure is arranged on the area between the proximal end and the distal end of the stent body; The stent body comprises a first grid and a second grid, and when the thrombus removal stent is in an expanded state, the area of ​​the first grid is greater than the area of ​​the second grid; The distance between the two main developing structures in the axial direction of the bracket body is defined as an axial spacing, and the size of a single second grid in the axial direction of the bracket body is a second size; multiple main developing structures with axial spacing less than the second size are divided into a group, and the convex structure is provided between two adjacent groups of main developing structures in the axial direction of the bracket body.

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