Thrombectomy stent

Abstract

The invention provides a thrombectomy stent, and relates to the technical field of medical instruments, and the thrombectomy stent comprises an outer-layer stent which is used for being placed on a human body; an inner stent; the inner-layer bracket is arranged in the outer-layer bracket; a fixing structure; the fixing structure is arranged on the inner-layer bracket; the outer-layer stent and the inner-layer stent are both made of shape memory alloy, and the inner-layer stent and the outer-layer stent drive the fixing structure to fix thrombus after being expanded and unfolded. By arranging the outer-layer stent, the inner-layer stent and the fixing structure, after the inner-layer stent and the outer-layer stent are released, the fixing structure fixes thrombus falling into the stent, the thrombus and the fixing structure are stably combined, and the risk that the thrombus escapes to the far end and causes secondary embolism is reduced.

Description

Technical Field

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

[0002] A stent retriever is an effective treatment for acute ischemic stroke. The stent retriever is delivered to the embolic site via a catheter and pushwire. Upon release, the thrombus is fixed within the stent. By pulling back on the pushwire and using an aspiration catheter, the stent and thrombus can be removed from the body, restoring vascular canalization.

[0003] Traditional stent retrievers rely on friction between meshes to secure thrombi. However, for hard (such as calcified thrombi) or smooth thrombi, the meshes provide insufficient friction, easily causing the thrombi to slip during withdrawal. Furthermore, during withdrawal, thrombi can escape through the gaps within the stent retriever due to blood flow impact or changes in vascular morphology, potentially leading to secondary embolism.

[0004] Based on this, the present application provides a thrombus removal stent in order to solve at least one of the above problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a thrombus removal stent. By setting a fixing structure on the inner stent, the fixing structure fixes the thrombus after the inner stent and the outer stent are released, so as to solve the problem that the thrombus removal stent in the prior art has insufficient friction with thrombi that are hard in texture (such as calcified thrombi) or have smooth surfaces, which easily causes the thrombus to slip during the withdrawal process and cause secondary embolism.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A thrombectomy stent, comprising:

[0008] The outer stent is used to be placed in the human body;

[0009] Inner support; the inner support is arranged inside the outer support;

[0010] Fixed structure; the fixed structure is arranged on the inner support;

[0011] The outer stent and the inner stent are both made of shape memory alloy. After the inner stent and the outer stent expand and unfold, they drive the fixed structure to fix the thrombus.

[0012] In a preferred embodiment, the fixing structure comprises:

[0013] A supporting section, the supporting section being arranged on the inner support;

[0014] Barb, the barb is arranged on the supporting segment.

[0015] In a further preferred embodiment, the fixing structure further comprises:

[0016] The rotating block is arranged on a side of the supporting section away from the end of the barb; the barb is rotatably connected to the supporting section.

[0017] In one embodiment, the fixing structures may be provided in multiple groups, and the multiple groups of fixing structures are evenly arranged in a circular array on the inner support.

[0018] In a preferred embodiment, the fixing structure is arranged at the distal end of the inner layer stent, where the distal end is the end farther from the doctor during surgery.

[0019] In one embodiment, the projection of the barb relative to the support segment at any angle does not exceed the outer edge of the support segment.

[0020] In a preferred embodiment, the barb is anchor-shaped with a pointed end.

[0021] In a further preferred embodiment, the multiple barbs in the multiple groups of fixing structures have different lengths, and the multiple barbs are distributed in an alternating pattern of long and short.

[0022] In one embodiment, the inner stent is disposed at the distal end of the outer stent.

[0023] In a preferred embodiment, a plurality of developing points are provided on the outer support, the inner support and the fixed structure.

[0024] Beneficial effects:

[0025] The present invention provides an outer stent, an inner stent and a fixing structure. After the inner stent and the outer stent are released, the fixing structure fixes the thrombus that falls into the stent, allowing the thrombus to be stably combined with the fixing structure, reducing the risk of the thrombus escaping to the distal end and causing secondary embolism. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings and the accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. Among them:

[0027] Figure 1 This is a front view used to illustrate the overall structure of the thrombus removal stent in the embodiment of the present application;

[0028] Figure 2 This is a side view used to illustrate the inner support structure in the embodiment of the present application;

[0029] Figure 3 This is a structural diagram used to illustrate the connection relationship between the support section, the barb and the rotating block in the embodiment of the present application.

[0030] In the figure: 1. Outer support; 2. Inner support; 3. Fixing structure;

[0031] 31. Support section; 32. Barb; 33. Rotating block. DETAILED DESCRIPTION

[0032] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described 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 are within the scope of protection of the present invention.

[0033] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0034] In the description of the present invention, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or to implicitly indicate the quantity of the technical features indicated. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more features.

[0036] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, it can be a fixed connection or a movable connection, a detachable connection or a non-detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be internal communication between two elements, indirect communication, or an interactive relationship between two elements.

[0037] In the description of the present invention, the "distal end" refers to the end farther from the doctor during surgery, and the "proximal end" refers to the end closer to the doctor during surgery.

[0038] In the description of the present invention, "before use" refers to the state in which the thrombectomy stent has not been used, has not entered the human body, or has not come into contact with body fluids such as blood, tissue fluid, etc. in the human body; and "during use" refers to the state in which the thrombectomy stent has entered the human body or has come into contact with body fluids such as blood, tissue fluid, etc. in the human body.

[0039] In the description of the present invention, the "gathered state" refers to a state in which the "outer layer support" and the "inner layer support" are attached to each other within a partial length range or the entire length range.

[0040] In the description of the present invention, the "in vivo environment" refers to the environment below the epidermis of the skin where body fluids exist, such as the dermis and subcutaneous tissue, or the inside of blood vessels and organs.

[0041] The present invention will be described in detail below with reference to the embodiments. It should be noted that the embodiments and features of the embodiments of the present invention can be combined with each other without conflict.

[0042] The present invention addresses the problem that the existing thrombus removal stent has insufficient friction with hard (such as calcified thrombus) or smooth thrombus, which easily causes the thrombus to slip during the withdrawal process and trigger secondary embolism.

[0043] Example 1:

[0044] Reference Figures 1 to 3 As shown, the present invention provides a thrombus removal stent, comprising: an outer layer stent 1, which is used to be placed in the human body; an inner layer stent 2; the inner layer stent 2 is arranged in the outer layer stent 1; a fixing structure 3; the fixing structure 3 is arranged on the inner layer stent 2; the outer layer stent 1 and the inner layer stent 2 are both made of shape memory alloy, and after the inner layer stent 2 and the outer layer stent 1 are expanded and unfolded, they drive the fixing structure 3 to fix the thrombus.

[0045] In this embodiment, it should be noted that the outer stent 1 and the inner stent 2 are both made of shape memory alloy, such as nickel-titanium alloy, which can be compressed and gripped in the microcatheter before being placed in the patient's blood vessel, and released after reaching the lesion location through the microcatheter. Under the action of body temperature, it automatically expands and combines with the thrombus; the fixing structure 3 can be a mesh structure arranged on the inner stent 2, which is expanded as the inner stent 2 expands, and the mesh holes are smaller than the outer stent 1 and the inner stent 2, so that the thrombus falling into the stent is captured and fixed during the withdrawal of the stent; it can also be a plurality of support plates and / or support rods arranged inside the inner stent 2, which are also made of shape memory alloy. During the process of the stent expanding and capturing the thrombus, the thrombus falling into the inner stent 2 is clamped from all directions for fixation; an outer stent 1 and an inner stent 2 are provided, and the outer stent 1 is mostly used to cut part of the thrombus in the blood vessel, so that it falls off from the blood vessel wall and then falls into the stent. The inner stent 2 is often a stent mesh hole slightly smaller than the outer stent 1, so that the smaller thrombus after cutting can be captured, thereby improving the capture efficiency.

[0046] In a preferred embodiment, the fixing structure 3 includes: a support segment 31 , which is provided on the inner support 2 ; and a barb 32 , which is provided on the support segment 31 .

[0047] In this embodiment, it should be noted that the ends of the barbs 32 are sharp, allowing them to better penetrate the thrombus. During use, the outer stent 1 and the inner stent 2 expand and bind to the thrombus. During this process, the barbs 32 penetrate the thrombus and form a fixed connection with the thrombus. Together with the mesh of the outer stent 1 and the inner stent 2, they clamp and secure the thrombus, preventing it from escaping distally.

[0048] In a further preferred embodiment, the fixing structure 3 further includes a rotating block 33 , which is disposed on a side of the supporting section 31 away from the end of the barb 32 ; the barb 32 is rotatably connected to the supporting section 31 .

[0049] In this embodiment, it should be noted that the rotating block 33 is made of shape memory metal material. Generally, before a stent thrombectomy operation is performed on a patient, the size, shape and position of the thrombus in the blood vessel are obtained through human angiography. Based on this, the rotating block 33 can be pre-processed into a structure that rotates a certain angle relative to the support section 31, so as to rotate and lift the barb 32, and adjust the barb 32 to a suitable angle for inserting into the thrombus; when the stent is transported, the rotating block 33 and the barb 32 are folded inside the stent and the sheath. After reaching the target position, the stent and the rotating block 33 automatically unfold due to the properties of their shape memory alloy. The rotating block 33 unfolds and pushes the barb 32, so that the barb 32 rotates to a suitable angle, and then can penetrate into the thrombus for fixation, thereby improving the fixation effect of the device on thrombi of different shapes.

[0050] Example 2:

[0051] Reference Figures 1 to 3 As shown, the present invention provides a thrombus removal stent, including all the contents of embodiment 1 and its preferred embodiments. In addition, the fixing structure 3 can be set to multiple groups, and the multiple groups of fixing structures 3 are evenly arranged in a circular array on the inner layer stent 2.

[0052] In this embodiment, it should be noted that the fixing structures 3 are arranged in multiple groups and evenly arranged in a circular array on the inner stent 2 so as to fix the thrombus in the stent from multiple angles and directions, thereby improving the fixing effect of the device.

[0053] In a preferred embodiment, the fixing structure 3 is disposed at the distal end of the inner layer support 2 .

[0054] In this embodiment, it should be noted that, generally, after the thrombus is captured by the thrombus removal stent, the thrombus needs to be removed from the body by retracting the stent. At this time, due to inertia, the thrombus in the stent is affected by the distal structure of the stent. By setting the fixed structure 3 at the distal end of the inner layer stent 2, the risk of the thrombus escaping from the stent during the retraction process can be reduced.

[0055] Example 3:

[0056] Reference Figures 1 to 3 As shown, the present invention provides a thrombus removal stent, including all the contents of Examples 1 to 2 and their preferred embodiments. In addition, the projection of the barb 32 relative to the support segment 31 at any angle does not exceed the outer edge of the support segment 31.

[0057] In this embodiment, it should be noted that the projection of the hook 32 relative to the support segment 31 at any angle does not exceed the outer edge of the support segment 31, that is, no matter which direction the hook 32 is tilted, it cannot pass through the side of the support segment 31 of the inner layer stent 2, thereby avoiding accidental damage to the blood vessel by the hook 32.

[0058] In a preferred embodiment, the barb 32 is anchor-shaped with a pointed end.

[0059] In this embodiment, it should be noted that the barb 32 is anchor-shaped, that is, the end of the barb 32 is provided with a gripping protrusion, which is a convex structure similar to a barb, which can prevent the thrombus from falling off after the barb 32 penetrates the thrombus. The end of the barb 32 is provided with a pointed portion, which enables it to be inserted into a thrombus with a hard texture (such as a calcified thrombus) or a smooth surface to fix it.

[0060] In a further preferred embodiment, the multiple barbs 32 in the multiple groups of fixing structures 3 have different lengths, and the multiple barbs 32 are distributed in a staggered manner with long and short lengths.

[0061] In this embodiment, it should be noted that due to the different shapes and sizes of the thrombus, the shapes of the side surfaces after falling into the stent are very likely to be asymmetric. Therefore, in order for the barbs 32 to accurately penetrate the interior of the thrombus and fix it, it is necessary to set the corresponding angles and lengths according to the shape of the thrombus, the distances from the side surfaces of the thrombus to the inner stent 2 and the barbs 32. By arranging the barbs 32 into multiple groups of a circular array and distributing them in a staggered manner of length, the device can further adapt to thrombi of different sizes and shapes, thereby improving the fixation effect of the device on thrombi.

[0062] Example 4:

[0063] Reference Figures 1 to 3 As shown, the present invention provides a thrombus removal stent, including all the contents of Examples 1 to 3 and their preferred embodiments. In addition, the inner layer stent 2 is arranged at the distal end of the outer layer stent 1.

[0064] In this embodiment, it should be noted that, generally, after the thrombus is captured by the thrombus removal stent, the thrombus needs to be removed from the body by retracting the stent. At this time, due to inertia, the thrombus in the stent is affected by the distal structure of the stent. The inner layer stent 2 is arranged at the distal end of the outer layer stent 1, which can reduce the risk of the thrombus escaping from the stent from the distal end during the retraction process.

[0065] In a preferred embodiment, a plurality of developing points are provided on the outer support 1 , the inner support 2 and the fixing structure 3 .

[0066] In this embodiment, it should be noted that the developing point can be a structure made of high-density material, which is used to form an image different from other positions of the bracket under X-ray, or a structure with a cavity inside, which is used to form an image different from other positions under ultrasound, thereby assisting doctors in determining the positions of the outer layer bracket 1, the inner layer bracket 2 and the fixed structure 3, and improving the convenience and safety of using the device.

[0067] In summary, the technical solution of this application has the following beneficial effects:

[0068] 1. The present invention provides an outer stent, an inner stent, and a fixing structure. After the inner stent and the outer stent are released, the fixing structure fixes the thrombus that falls into the stent, thereby solving the problem that the existing thrombus removal stent is difficult to stably fix thrombi with a hard texture (such as calcified thrombi) or a smooth surface. The thrombus is stably combined with the fixing structure, reducing the risk of the thrombus escaping to the distal end and causing secondary embolism.

[0069] 2. The present invention sets a fixed structure as a support section and a barb, and sets a rotating block, which is made of shape memory alloy, so that when the stent is transported, the rotating block and the barb are folded inside the stent and the sheath. After reaching the target position, the stent and the rotating block automatically unfold due to the properties of the shape memory alloy. The rotating block 33 unfolds and pushes the barb, so that the barb rotates to a suitable angle, and then can penetrate into the thrombus for fixation, thereby improving the fixation effect of the device on thrombi of different shapes.

[0070] 3. The present invention provides multiple sets of fixing structures and multiple sets of barbs, and arranges the barbs in a staggered distribution of shapes and lengths, so that the present invention can further adapt to thrombi of different sizes and shapes, thereby improving the fixation effect of the device on thrombi.

[0071] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A thrombus removal stent, characterized in that: include: An outer layer support (1), the outer layer support (1) being used for placement in a human body; An inner layer support (2); the inner layer support (2) is arranged inside the outer layer support (1); A fixing structure (3); the fixing structure (3) is arranged on the inner layer support (2); The outer layer stent (1) and the inner layer stent (2) are both made of shape memory alloy, and after the inner layer stent (2) and the outer layer stent (1) are expanded and deployed, they drive the fixing structure (3) to fix the thrombus.

2. The thrombus removal stent according to claim 1, characterized in that: The fixing structure (3) comprises: A support section (31), the support section (31) being arranged on the inner layer support (2); A barb (32), wherein the barb (32) is arranged on the supporting section (31).

3. The thrombus removal stent according to claim 2, characterized in that: The fixed structure (3) further comprises: a rotating block (33), the rotating block (33) being arranged on a side of the supporting section (31) away from the end of the barb (32); The barb (32) is rotatably connected to the supporting section (31).

4. The thrombus removal stent according to claim 1, characterized in that: The fixing structures (3) can be arranged in multiple groups, and the multiple groups of fixing structures (3) are evenly arranged in a circular array on the inner layer support (2).

5. The thrombus removal stent according to claim 1, characterized in that: The fixing structure (3) is arranged at the distal end of the inner layer support (2), and the distal end is the end farther away from the doctor during surgery.

6. The thrombus removal stent according to claim 2, characterized in that: The projection of the barb (32) relative to the support section (31) at any angle does not exceed the outer edge of the support section (31).

7. The thrombus removal stent according to claim 2, characterized in that: The barb (32) is in the shape of an anchor, with a tip at the end.

8. The thrombus removal stent according to claim 4, characterized in that: The lengths of the plurality of barbs (32) in the plurality of groups of the fixing structures (3) are different, and the plurality of barbs (32) are staggered in length.

9. The thrombus removal stent according to any one of claims 1 to 8, characterized in that: The inner layer support (2) is arranged at the distal end of the outer layer support (1).

10. The thrombus removal stent according to any one of claims 1 to 8, characterized in that: A plurality of developing points are provided on the outer layer support (1), the inner layer support (2) and the fixed structure (3).

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