Intravascular thrombus removal device

Abstract

The present invention relates to an intravascular thrombus removal device, comprising a self-expandable stent body in a mesh tube structure, the stent body comprising a proximal end and a distal end, the mesh tube structure gathered at the proximal end and the distal end; the stent body comprising a plurality of repeating units, the plurality of repeating units being arranged in sequence along the axial direction; the repeating unit comprising a plurality of closed grid units arranged in sequence along the circumference of the mesh tube structure; the closed grid unit comprising a first mesh and a plurality of second meshes arranged adjacent to the first mesh. The present invention arranges the first mesh and the plurality of second meshes adjacent to each other, and the area of ​​the first mesh is larger than the area of ​​the second mesh, so that the larger-sized first mesh can facilitate the removal of thrombus, and can allow the removed thrombus fragments to enter the stent body in the mesh tube structure through the first mesh; the smaller-sized second mesh can effectively prevent the thrombus fragments from escaping from the inside of the stent body, and the first mesh and the plurality of second meshes cooperate with each other to better capture the thrombus fragments.

Description

Technical Field

[0001] The invention relates to an interventional treatment medical device in the field of medical devices, and in particular to an intravascular thrombus removal device. Background Art

[0002] Acute ischemic stroke refers to the obstruction of blood supply to the brain tissue caused by stenosis or occlusion of the blood supply arteries to the brain, which leads to localized brain tissue necrosis and symptoms and signs of focal neurological deficits. Among all stroke patients, acute ischemic stroke accounts for about 70%-80%. At present, there are two main treatment methods for acute ischemic stroke, drug thrombolysis and mechanical thrombectomy. Arterial and intravenous drug thrombolysis is a conventional method for the treatment of acute ischemic stroke, but this method has a relatively high requirement for the rescue time window. Intravenous thrombolysis should be performed within 3 hours of onset, and the time window for arterial thrombolysis is only 6 hours; secondly, the vascular recanalization time of drug thrombolysis is long, and thrombolytic therapy is only suitable for smaller thrombi. The vascular recanalization rate of acute ischemic stroke caused by severe large vessel occlusion is low. Mechanical thrombectomy has become the preferred treatment for anterior circulation and large vessel occlusion stroke. The mechanical thrombectomy process is to pass the stent body through the intracranial blood vessels through the vascular pathway, use the porous mesh structure of the stent body to capture the thrombus and mechanically remove the thrombus from the body, thereby restoring blood flow in the intracranial blood vessels.

[0003] Because of its adhesion to the blood vessel wall, the radial supporting force of the stent body in the prior art is too great, which can easily cause irreversible damage to the blood vessel wall. In severe cases, it can lead to other complications such as blood vessel rupture. The stent body in the prior art is not conducive to capturing thrombus fragments and dragging thrombi. In the process of capturing and dragging thrombi, small thrombus fragments may fall off from the stent body. The detached thrombus fragments flow to the distal end of the blood vessel under the impact of blood flow to form new embolism, thereby causing the risk of stroke. Summary of the invention

[0004] Based on this, it is necessary to provide an intravascular thrombus removal device that is conducive to removing thrombi and capturing thrombus fragments and can prevent thrombus fragments from escaping.

[0005] An intravascular thrombus removal device comprises a stent body having a mesh tube-like structure along the axial direction, wherein the stent body has a self-expanding state and a compressed state after being stressed;

[0006] The stent body comprises a proximal portion, a middle portion and a distal portion arranged along the axial direction, the middle portion comprises a plurality of repeating units, and the plurality of repeating units are arranged in sequence along the axial direction;

[0007] The repeating unit includes a plurality of closed mesh units arranged in sequence along the circumference of the mesh tube-like structure; each closed mesh unit includes a first mesh hole and a plurality of second mesh holes arranged adjacent to the first mesh hole, and the area of ​​the first mesh hole is larger than the area of ​​the second mesh hole.

[0008] By arranging the first mesh and a plurality of second meshes adjacent to each other, and the area of ​​the first mesh is larger than that of the second mesh, the larger-sized first mesh can be beneficial for removing thrombus, and can allow the removed thrombus fragments to enter the stent body with a mesh tube-like structure through the first mesh; the smaller-sized second mesh can effectively prevent thrombus fragments from escaping from the inside of the stent body, and the first mesh and the plurality of second meshes cooperate with each other to better capture thrombus fragments.

[0009] In one embodiment, the proximal portion, the plurality of repeating units and the distal portion are distributed in a spiral along the axial direction.

[0010] In one embodiment, two adjacent repeating units are connected by rotating upwardly along the axis at an angle α.

[0011] In one embodiment, a plurality of developing units are distributed on the proximal portion, the distal portion and a plurality of the repeating units; the plurality of developing units on the proximal portion and the distal portion are arranged at intervals; and the developing units on two adjacent repeating units are distributed in an axial spiral.

[0012] In one embodiment, the developing units on the distal end portion form a plurality of developing structures spaced apart along the circumference of the mesh tube-like structure, and two adjacent developing units in the same group are arranged in parallel in the axial direction and spaced apart from each other in the circumference of the mesh tube-like structure.

[0013] In one embodiment, each of the repeating units includes two developing units, and the two developing units in the same repeating unit are symmetrically arranged along the axial direction.

[0014] In one embodiment, the proximal portion is gathered at an end away from the distal portion to form a proximal tubular structure, and the intravascular thrombus removal device further includes:

[0015] A first developing spring, the first developing spring comprising a proximal connecting portion and a distal connecting portion, the proximal connecting portion being connected to the proximal tubular structure;

[0016] A push rod, wherein a connecting clamp is formed at one end of the push rod close to the proximal end; the end of the push rod close to the proximal end is passed through the proximal connecting portion and the proximal tubular structure, the distal connecting portion is arranged between the connecting clamp and the proximal tubular structure, and the connecting clamp is abutted against the distal connecting portion.

[0017] In one embodiment, the distal portion gathers at an end away from the proximal portion to form a distal tubular structure, and the intravascular thrombus removal device further includes a second developing spring connected to the distal tubular structure.

[0018] In one embodiment, the area of ​​the first mesh is 1.5-2.5 times the area of ​​the second mesh; the distal end portion includes a plurality of closed meshes, and the plurality of closed meshes are arranged in a preset manner so that the end of the distal end portion away from the proximal end portion presents a closed structure, and the area of ​​the closed mesh is ≤ the area of ​​the second mesh.

[0019] In one embodiment, the material of the stent body is a nickel-titanium alloy tubular material, and the diameter of the nickel-titanium alloy tubular material is ≤0.4 mm.

[0020] In the above scheme, by arranging the first mesh and several second meshes adjacent to each other, and the area of ​​the first mesh is larger than that of the second mesh, the larger-sized first mesh can be beneficial for removing thrombus, and can allow the removed thrombus fragments to enter the stent body with a mesh tube-like structure through the first mesh; the smaller-sized second mesh can effectively prevent thrombus fragments from escaping from the inside of the stent body, and the first mesh and several second meshes cooperate with each other to better capture thrombus fragments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic structural diagram of an intravascular thrombus removal device according to an embodiment of the present invention;

[0022] Figure 2 It is a structural schematic diagram of a bracket body shown in one embodiment of the present invention;

[0023] Figure 3 It is a schematic diagram of a plane expansion of a bracket body shown in an embodiment of the present invention;

[0024] Figure 4 It is a schematic diagram of the connection structure of the bracket body, the pushing rod and the first developing spring shown in one embodiment of the present invention.

[0025] Description of Reference Numerals

[0026] 10. Intravascular thrombus removal device; 100. Stent body; 110. Proximal portion; 120. Repeating unit; 121. Closed grid unit; 1211. First mesh; 1212. Second mesh; 130. Distal portion; 131. Closed mesh; 200. Development unit; 300. First development spring; 310. Proximal connecting portion; 320. Distal connecting portion; 400. Second development spring; 500. Push rod; 600. Connecting clamp; 700. Proximal tubular structure; 800. Distal tubular structure. DETAILED DESCRIPTION

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0028] In the description of the present invention, it is necessary to understand that the term "axial" should be understood as the direction in which the device of the present invention is advanced, that is, the longitudinal axis of the device of the present invention, and coincides with the longitudinal axis of the blood vessel along which the device of the present invention moves forward. The term "circumferential" should be understood as the circumferential direction of the device of the present invention, that is, the direction around the axis of the device of the present invention, the circumferential direction of the device of the present invention is perpendicular to the longitudinal axis of the device of the present invention, and coincides with the circumferential direction of the blood vessel along which the device of the present invention moves forward. The term "radial" should be understood as the radial direction of the device of the present invention, that is, the straight line direction perpendicular to the longitudinal axis of the device of the present invention, and coincides with the radial direction of the blood vessel along which the device of the present invention moves forward.

[0029] For ease of description and understanding, the terms "distal" and "proximal" should be understood as viewed from the direction of the handheld end of the attending physician or medical interventionist. The distal end is the side away from the handheld end of the attending physician or medical interventionist, while the proximal end refers to the side toward the handheld end of the attending physician or medical interventionist. If the phrase "axial" is used in this document, it is understood to mean the direction in which the device of the present invention is advanced, that is, the longitudinal axis of the device also coincides with the longitudinal axis of the blood vessel along which the device moves forward.

[0030] See also Figure 1 As shown, an embodiment of the present invention provides an intravascular thrombus removal device 10, comprising a stent body 100 having a mesh tube structure along the axial direction, the stent body 100 having a self-expanding state and a compressed state after being subjected to force, in the compressed state, it can be easily delivered in the blood vessel to deliver the stent body 100 to the thrombus position. In the self-expanding state, the thrombus at the thrombus position can be cut and captured, and finally the captured thrombus can be withdrawn, thereby achieving dredging of the blocked blood vessel to restore blood flow in the blood vessel artery.

[0031] It should be understood that the degree of compression or self-expansion of the stent body 100 is mainly affected by the thickness of the blood vessel at the location. The thinner the blood vessel, the greater the degree of compression, and the smaller the degree of self-expansion of the stent body 100. The degree of expansion of the stent body 100 is also affected by the texture of the embolic thrombus at the location. The softer and looser the texture of the thrombus, the greater the expansion of the stent body 100; the harder and denser the texture of the thrombus, the smaller the expansion of the stent body 100. Usually, after being released, the stent body 100 will stay for 3 minutes to 5 minutes to expand the stent body 100 as much as possible, so that it can be more embedded in the thrombus tissue and fully combined with the stent body 100.

[0032] See also Figure 1 , Figure 2 and Figure 3 As shown, the stent body 100 includes a proximal portion 110, a middle portion and a distal portion 130 arranged in the axial direction. Among them, the middle portion includes a plurality of repeating units 120, and the plurality of repeating units 120 are arranged in sequence in the axial direction. The repeating unit 120 includes a plurality of closed mesh units 121 arranged in sequence along the circumference of the net-tube-like structure. Each closed mesh unit 121 includes a first mesh 1211 and a plurality of second meshes 1212 arranged adjacent to the first mesh 1211, and the area of ​​the first mesh 1211 is greater than the area of ​​the second mesh 1212. In this embodiment, the first mesh 1211 in the same repeating unit 120 is arranged adjacent to the first mesh 1211 in the circumference of the net-tube-like structure.

[0033] The area of ​​the first mesh 1211 is 1.5-2.5 times the area of ​​the second mesh 1212. In this embodiment, the middle portion includes three repeating units 120, and the repeating unit 120 includes two closed grid units 121 arranged in sequence along the circumference of the mesh tube-like structure. In other embodiments, the number of the repeating unit 120 and the closed grid unit 121 can be single or multiple, which is not limited here and can be adjusted according to specific needs.

[0034] When clearing a thrombus, the first mesh 1211 and the plurality of second meshes 1212 are arranged adjacent to each other, and the area of ​​the first mesh 1211 is larger than that of the second mesh 1212. The larger-sized first mesh 1211 is conducive to the removal of the thrombus, and allows the removed thrombus fragments to enter the stent body 100 with a mesh tube structure through the first mesh 1211; the smaller-sized second mesh 1212 can effectively prevent thrombus fragments from escaping from the inside of the stent body 100. The first mesh 1211 and the plurality of second meshes 1212 cooperate with each other to better capture thrombus fragments.

[0035] The first mesh 1211 generates a weak radial support force when capturing a thrombus, which can reduce excessive stimulation to the blood vessel wall; at the same time, the second mesh 1212 generates a larger radial support force when capturing a thrombus, which can quickly embed into the thrombus, increase the stability of thrombus capture, and effectively prevent thrombus fragments from escaping from the inside of the stent body 100. It should be understood that the radial support force is the force generated by the stent body 100 on the blood vessel wall in the self-expanding state. When the first mesh 1211 with a larger size is subjected to the same force, it is easier to deform due to the smaller coverage rate per unit area, so the radial support force generated by the first mesh 1211 with a larger size when capturing a thrombus is weaker. When the second mesh 1212 with a smaller size is subjected to the same force, it is subjected to a smaller pressure due to the larger coverage rate per unit area, so the second mesh 1212 generates a larger radial support force when capturing a thrombus.

[0036] See also Figure 1 , Figure 2 and Figure 3 As shown, the proximal end is gathered at the end away from the distal end, and the distal end is gathered at the end away from the proximal end. That is to say, the proximal end and the distal end of the stent body 100 are both in a closed state, which can effectively prevent thrombus fragments from escaping from the proximal end and the distal end of the stent body, and is more conducive to capturing thrombus fragments.

[0037] The proximal portion 110 includes a plurality of closed meshes 131, and the plurality of closed meshes 131 are arranged in a preset manner so that the proximal portion is in a closed structure. The plurality of closed meshes 131 are interconnected and intersect at the nearest end so that the end of the proximal portion away from the distal portion is in a closed structure. The distal portion 130 includes a plurality of closed meshes 131, and the plurality of closed meshes 131 are arranged in a preset manner so that the end of the distal portion away from the proximal portion is in a closed structure. In other words, the distal portion 130 is a closed mesh 131 that is interconnected and intersects at the farthest end so that the farthest end is in a closed structure.

[0038] The area of ​​the closed mesh 131 is ≤ the area of ​​the second mesh 1212. When the stent body 100 is withdrawn, the distal end 130 formed by connecting the smaller closed meshes 131 can block the thrombus fragments that have fallen into the stent body 100. During the withdrawal process, the thrombus is not easy to fall off, which is more conducive to dragging the thrombus and preventing the escape of thrombus fragments.

[0039] The inventors found that the stent bodies currently on the market in China can only reach blood vessels with a diameter of more than 1.5 mm. For thinner distal blood vessels, it is impossible to remove thrombi from vascular embolism sites with smaller blood vessel diameters (blood vessel diameter < 1.5 mm). In order to solve the above problem, the applicant made the following settings:

[0040] See also Figure 1As shown, the material of the stent body 100 is a nickel-titanium alloy tubular material, and the diameter of the nickel-titanium alloy tubular material is ≤0.4mm. Specifically, the stent body 100 is made in one piece using a laser engraving or laser cutting process. It should be understood that nickel-titanium alloy has superelasticity and shape memory, and can remember the finalized shape after being heat-treated and finalized. Therefore, the stent body 100 made of nickel-titanium alloy has sufficient radial supporting force, superelasticity and shape memory, and can ensure good wall adhesion. What needs to be understood more is that the stent body 100 can maintain a compressed state under the action of the external circumferential restraint force. When the external circumferential restraint force is removed, the stent body 100 made of nickel-titanium alloy can return to its original shape.

[0041] For example, the diameter of the nickel-titanium alloy tubular material is 0.4 mm. It should be understood that when the diameter of the nickel-titanium alloy tubular material is 0.4 mm, the minimum compressed diameter of the stent body 100 in the compressed state is also the diameter of the nickel-titanium alloy tubular material, that is, 0.4 mm. The present invention can be delivered in blood vessels with smaller diameters, and can be delivered through blood vessels with a minimum diameter of 0.43 mm, and can reach more tortuous and small distal blood vessels in the brain.

[0042] See also Figure 2 and Figure 3 As shown, the proximal portion 110, the plurality of repeating units 120 and the distal portion 130 are spirally distributed along the axial direction. Specifically, the plurality of closed meshes 131 of the distal portion 130, the plurality of repeating units 120 and the plurality of closed meshes 131 of the proximal portion 110 are spirally distributed in sequence along the axial direction.

[0043] More specifically, two adjacent repeating units 120 are connected by rotating an angle α along the axial direction, that is, the second of the two adjacent repeating units 120 is rotated an angle α relative to the first in the circumferential direction. The angle range of α is 0°-90°. The preferred angle range of α is 45°. For example, the repeating unit 120 includes a first repeating unit, a second repeating unit and a third repeating unit, the second repeating unit is rotated an angle α relative to the first repeating unit, and the third repeating unit is rotated an angle α relative to the second repeating unit.

[0044] By connecting two adjacent repeating units 120 by rotating them at an angle of α in the axial direction, the first meshes 1211 of the two adjacent repeating units 120 are not on the same connecting line in the axial direction, so that the first meshes 1211 are distributed in a spiral in the axial direction. When clearing thrombus, the stent body 100 can rotate by itself, and by distributing the first meshes 1211 in a spiral in the axial direction, the first meshes 1211 with larger sizes are distributed in the axial and circumferential directions, which can more effectively remove thrombus.

[0045] In this embodiment, the first meshes 1211 of two adjacent repeating units 120 are arranged adjacent to each other. The two adjacent first meshes 1211 are connected by rotating an angle α along the axis, and the angle range of α is 0°-90°. The preferred angle range of α is 45°.

[0046] The inventors found that the poor radiopaque effect of the stent body can also lead to problems such as inaccurate positioning of the stent body, long thrombus removal time, and thrombus shedding. In order to solve the above problems, the applicant made the following settings:

[0047] See also Figure 1 and Figure 3 As shown, a plurality of developing units 200 are distributed on the proximal portion 110, the distal portion 130 and the plurality of repeating units 120. The connection method of the developing unit 200 with the proximal portion 110, the distal portion 130 and the plurality of repeating units 120 can be mechanical structure nesting, crimping, metal ring, laser welding, adhesive bonding, etc., which can be one of the connection methods or a combination of multiple connection methods, which is not limited here and can be adjusted according to specific needs.

[0048] Specifically, the developing units 200 on two adjacent repeating units 120 are distributed in a spiral along the axial direction, so that the developing units 200 on two adjacent repeating units 120 are not on the same straight line. Each repeating unit 120 includes two developing units 200, and the two developing units 200 in the same repeating unit 120 are symmetrically arranged along the axial direction. By distributing the developing units 200 on two adjacent repeating units 120 in a spiral along the axial direction, and arranging the two developing units 200 of each repeating unit 120 symmetrically along the axial direction, the spatial resolution and visibility of the developing units 200 can be increased, thereby improving the spatial resolution and visibility of the bracket body 100. More specifically, the developing units 200 on two adjacent repeating units 120 are arranged at an angle α, and the angle range of α is 0°-90°. The preferred angle range of α is 45°.

[0049] Several developing units 200 on the proximal portion 110 and the distal portion 130 are arranged at intervals. More specifically, the developing units 200 on the distal portion 130 form a plurality of groups of developing structures arranged at intervals along the circumference of the mesh tube-like structure, and two adjacent developing units 200 in the same group are arranged in parallel in the axial direction and are spaced apart in the circumferential direction of the mesh tube-like structure. In the present embodiment, there are two groups of developing structures, each group of developing structures includes two developing units 200, and two developing units 200 are arranged on the proximal portion 110. In other feasible embodiments, two adjacent developing units 200 are spaced apart in the axial direction and in the circumferential direction of the mesh tube-like structure. The number of groups of developing structures and the number of developing units 200 may also be multiple, which are not limited here and can be adjusted according to specific needs.

[0050] The developing unit 200 is made of a metal material that is not transparent to X-rays, and can be any one of gold, platinum, tungsten, tantalum or platinum-iridium alloy. The attending physician or medical interventional physician can view the position of the developing unit 200 through DSA (digital subtraction angiography), which can help the attending physician or medical interventional physician to better observe the state of the stent body 100, and further determine the capture of the thrombus by the stent body 100.

[0051] See also Figure 1 , Figure 2 and Figure 3 As shown, the intravascular thrombus removal device 10 also includes a first developing spring 300 and a second developing spring 400. The proximal end is gathered at an end away from the distal end to form a proximal tubular structure 700, and the first developing spring 300 is connected to the proximal tubular structure 700. The distal end is gathered at an end away from the proximal end to form a distal tubular structure. The second developing spring 400 is connected to the distal tubular structure 800. The connection method of the first developing spring 300 and the proximal tubular structure 700 and the second developing spring 400 and the distal tubular structure 800 can be mechanical structure nesting, crimping, metal ring, laser welding, adhesive bonding, etc., which can be one of the connection methods or a combination of multiple connection methods. It is not limited here and can be adjusted according to specific needs.

[0052] The first developing spring 300 and the second developing spring 400 are made of metal materials that are not transparent to X-rays, and can be any one of gold wire, platinum wire or platinum-tungsten alloy wire. The attending physician or medical interventional physician can view the positions of the first developing spring 300 and the second developing spring 400 that are not transparent to X-rays through DSA (digital subtraction angiography), which can help the attending physician or medical interventional physician to better observe the positions of the proximal and distal ends of the stent body 100.

[0053] The inventor found that the connection between the majority of stent bodies and the push rods and developing springs on the market is mostly connected by simple welding. Due to the process defects of welding itself, it is easy to cause the welding points to fall off or break, causing the stent body to be damaged and fall off in the human blood vessels, leading to serious clinical accidents. In order to solve the above problems, the applicant made the following settings:

[0054] See also Figure 1 , Figure 3 and Figure 4As shown, the intravascular thrombus removal device 10 further includes a push rod 500, and a connection clamp 600 is formed at one end of the push rod 500 near the proximal end. The first developing spring 300 includes a proximal connection portion 310 and a distal connection portion 320, and the proximal connection portion 310 is connected to the proximal tubular structure 700. One end of the push rod 500 near the proximal end is inserted through the proximal connection portion 310 and the proximal tubular structure 700, and the distal connection portion 320 is disposed between the connection clamp 600 and the proximal tubular structure 700, and the connection clamp 600 can abut against the distal connection portion 320.

[0055] Specifically, the inner diameter of the proximal tubular structure 700 is larger than the diameter of the connecting clamp 600, and the inner diameter of the proximal connecting portion 310 is larger than the diameter of the connecting clamp 600. During assembly, the connecting clamp 600 and the push rod 500 can pass through the proximal connecting portion 310 and the proximal tubular structure 700. The inner diameter of the distal connecting portion 320 is smaller than the diameter of the connecting clamp 600 and larger than the inner diameter of the proximal tubular structure 700. By arranging the distal connecting portion 320 between the connecting clamp 600 and the proximal tubular structure 700, the connecting clamp 600 can be effectively prevented from falling off from the proximal end of the stent body 100, effectively solving the problem of the stent body 100 being damaged and falling off in the human blood vessel.

[0056] The connection method of the proximal tubular structure 700 with the first developing spring 300 and the push rod 500 can adopt the above-mentioned nesting method, and then be connected by welding, adhesive bonding, etc., which is a combination of multiple connection methods, which is not limited here and can be adjusted according to specific needs. For example, the proximal connecting part 310 is welded to the proximal tubular structure 700, and the connecting clamp 600 is welded to the proximal tubular structure 700 through the distal connecting part 320.

[0057] The intravascular thrombus removal device 10 of the present invention is used in conjunction with a microcatheter. When in use, the position of the thrombus in the blood vessel is first determined by DSA (digital subtraction angiography), and then the microcatheter is transported to the thrombus position and passes through the thrombus.

[0058] The stent body 100 is pushed to the thrombus position by the push and pull action of the push rod 500, and the second developing spring 400 is checked by DSA (digital subtraction angiography) to determine the position of the farthest end of the stent body 100. After the farthest end of the stent body 100 is adjusted to a suitable position, the microcatheter is withdrawn. As the microcatheter is withdrawn, the stent body 100 will self-expand and unfold at the thrombus position, and the repeating unit 120 in the middle part of the stent body 100 will be embedded in the thrombus. At the same time, the multiple closed meshes 131 of the distal end 130 of the stent body 100 will also self-expand and unfold.

[0059] Among them, the first mesh 1211 and the plurality of second meshes 1212 of the repeating unit 120 are arranged adjacent to each other, and the area of ​​the first mesh 1211 is larger than that of the second mesh 1212. The larger-sized first mesh 1211 can be beneficial to the removal of thrombus, and can allow the removed thrombus fragments to enter the stent body 100 with a mesh tube structure through the first mesh 1211; the smaller-sized second mesh 1212 can effectively prevent thrombus fragments from escaping from the inside of the stent body 100. The first mesh 1211 and the plurality of second meshes 1212 cooperate with each other to better capture thrombus fragments.

[0060] When the microcatheter is withdrawn until the distal outlet of the microcatheter is aligned with the first developing spring 300, the stent body 100 is completely released from the microcatheter. Wait for 3 to 5 minutes to allow the stent body 100 to fully fit with the thrombus. Then, the microcatheter, the stent body 100 and the push rod 500 are synchronously withdrawn until the stent body 100 and the thrombus are pulled out of the body, completing the thrombus removal operation.

[0061] Among them, the distal end 130 is connected to each other by smaller closed meshes 131, and intersects at the farthest end to make the farthest end a closed structure. When the stent body 100 is retracted, the distal end 130 formed by connecting the smaller closed meshes 131 can block the thrombus fragments that have fallen into the stent body 100. During the retraction process, the thrombus is not easy to fall off, which is more conducive to dragging the thrombus and can prevent the escape of thrombus fragments.

[0062] 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.

[0063] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An intravascular thrombus removal device, characterized in that: It includes a stent body with a mesh tube-like structure along the axial direction, and the stent body has a self-expanding state and a compressed state after being stressed; The stent body comprises a proximal portion, a middle portion and a distal portion arranged along the axial direction, the middle portion comprises a plurality of repeating units, and the plurality of repeating units are arranged in sequence along the axial direction; The proximal portion, the plurality of repeating units and the distal portion are distributed in an axial spiral; The proximal portion is gathered at an end away from the distal portion to form a proximal tubular structure; the distal portion is gathered at an end away from the proximal portion to form a distal tubular structure; the nearest end of the proximal portion and the farthest end of the distal portion are both joined by a closed mesh structure to form a closed structure; And, the plurality of repeating units in the middle part are spirally symmetrical about the stent body: the second of the two adjacent repeating units is rotated relative to the first in the circumferential direction by an angle α; the repeating unit comprises a plurality of closed mesh units sequentially arranged along the circumference of the mesh tube-like structure; each closed mesh unit comprises a first mesh and a plurality of second meshes arranged adjacent to the first mesh, and the area of ​​the first mesh is larger than the area of ​​the second mesh; A first developing spring, the first developing spring comprising a proximal connecting portion and a distal connecting portion, the proximal connecting portion being connected to the proximal tubular structure; A push rod, wherein a connecting clamp is formed at one end of the push rod close to the proximal end; the end of the push rod close to the proximal end is passed through the proximal connecting portion and the proximal tubular structure, the distal connecting portion is arranged between the connecting clamp and the proximal tubular structure, and the connecting clamp is abutted against the proximal tubular structure through the distal connecting portion.

2. The intravascular thrombus removal device according to claim 1, characterized in that: Two adjacent repeating units are connected by rotating upward along the axis at an angle of α.

3. The intravascular thrombus removal device according to claim 1, characterized in that: A plurality of developing units are distributed on the proximal end portion, the distal end portion and a plurality of the repeating units; the plurality of developing units on the proximal end portion and the distal end portion are arranged at intervals; and the developing units on two adjacent repeating units are distributed in a spiral along the axial direction.

4. The intravascular thrombus removal device according to claim 3, characterized in that: The developing units on the distal end portion form a plurality of developing structures spaced apart along the circumferential direction of the net-tube-like structure, and two adjacent developing units in the same group are arranged in parallel in the axial direction and spaced apart in the circumferential direction of the net-tube-like structure.

5. The intravascular thrombus removal device according to claim 3, characterized in that: Each of the repeating units includes two developing units, and the two developing units in the same repeating unit are symmetrically arranged along the axial direction.

6. The intravascular thrombus removal device according to claim 1, characterized in that: Also included is a second developing spring connected to the distal tubular structure.

7. The intravascular thrombus removal device according to claim 1, characterized in that: The first mesh holes are distributed in a spiral manner along the axial direction of the stent body, so as to facilitate the self-rotation of the stent body to cut off the thrombus.

8. The intravascular thrombus removal device according to claim 1, characterized in that: The area of ​​the first mesh is 1.5-2.5 times the area of ​​the second mesh.

9. The intravascular thrombus removal device according to claim 1, characterized in that: The distal end portion includes a plurality of closed meshes, and the plurality of closed meshes are arranged in a preset manner so that the end of the distal end portion away from the proximal end portion presents a closed structure, the area of ​​the closed meshes is ≤ the area of ​​the second meshes, and the closed meshes are used to block the thrombus falling into the stent body.

10. The intravascular thrombus removal device according to claim 1, characterized in that: The material of the stent body is a nickel-titanium alloy tubular material, and the diameter of the nickel-titanium alloy tubular material is ≤0.4 mm.

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