Thrombus removal system and assisted recovery system

Abstract

The present invention relates to a thrombus removal system and an assisted recovery system. The thrombus removal system comprises: a thrombus retrieval device, comprising a push-pull guide wire and a thrombus retrieval stent that are sequentially connected in the axial direction of the thrombus retrieval device; and an assisted recovery system, comprising a recovery catheter, a push-pull device, and a self-expansion stent, wherein the proximal end of the self-expansion stent is connected to the distal end of the push-pull device; the push-pull device is used for being slidably arranged in the recovery catheter and used for pushing and pulling the self-expansion stent in the axial direction of the recovery catheter; the self-expansion stent has a compressed state when being delivered in the recovery catheter and an expanded state when being partially separated from the recovery catheter; the assisted recovery system is used for moving along the push-pull guide wire to be positioned on the proximal side of the thrombus retrieval stent, and then the self-expansion stent is partially separated from the recovery catheter to be expanded; when capturing a target object, the thrombus retrieval stent moves towards the proximal side under the pulling of the push-pull guide wire to at least partially enter the self-expansion stent, so that the thrombus retrieval stent is withdrawn under the protection of the self-expansion stent, thereby preventing a thrombus from entering a side branch vessel blood and a blood vessel at a distal end.

Description

Thrombus removal system and auxiliary recovery system Technical Field

[0001] The present invention relates to the field of medical devices, and in particular to a thrombus removal system and an auxiliary recovery system. Background Art

[0002] Embolism refers to the phenomenon in which abnormal substances insoluble in blood appear in the circulating blood, flow with the blood, and then block the blood vessel lumen. When a thrombus occurs in the coronary artery, the patient will experience symptoms such as sudden chest pain or discomfort, shortness of breath, sweating, dizziness, nausea, and vomiting, which may lead to myocardial ischemia and myocardial infarction. When a thrombus occurs in the cerebral vascular system and blocks blood flow to the brain, the patient will experience symptoms such as sudden severe headache, dizziness, aphasia, limb weakness or numbness, blurred vision, blindness or double vision, facial numbness or drooping, impaired consciousness, and coma, which may cause localized brain tissue ischemia and necrosis.

[0003] Thrombi in the brain or coronary arteries are usually hard, but they can also be soft or semi-hard and semi-soft. Fresh thrombi are softer and easier to dissolve, which are called red thrombi. These thrombi are usually soft and fragile. Over time, platelets and fibrin will gradually combine together, causing the thrombus to gradually harden and form the so-called white thrombus. This thrombus is rich in fiber, has strong viscoelasticity, and is difficult to compress. Stent thrombectomy is a common mechanical thrombus removal method that can quickly recanalize occluded blood vessels and improve the recanalization rate. Currently, most thrombus removal stents are self-expanding structures. They are compressed and placed in a microcatheter before use. When used, the microcatheter is passed through the thrombus and then withdrawn. The thrombus removal stent self-expands in an unconstrained state. During this process, the stent rod is gradually embedded in the thrombus or the thrombus penetrates the stent rod and enters the lumen of the thrombus removal stent. The guide wire is then pulled proximally to collect the thrombus removal stent and the thrombus into the retrieval catheter together.

[0004] However, current stent retrievers are not ideal for removing thrombi, especially within the intracranial and coronary arteries. These vessels are tortuous and may harbor plaques or calcified lesions, making thrombus removal difficult. Furthermore, the stent retriever must travel a considerable distance from the occluded site back into the retrieval catheter. During this process, soft, red thrombi can break apart, and the resulting thrombus fragments can easily escape to distal vessels, forming new emboli. In particular, the intracranial, especially coronary, vessels contain numerous collateral vessels. During the process of stent retriever withdrawal, thrombi can fall from the stent retriever into collateral and distal vessels, triggering new emboli and even life-threatening in the coronary arteries.

[0005] It should be noted that the information disclosed in the background technology section of this application is only intended to deepen the understanding of the general background technology of this application, and should not be regarded as an admission or any form of implication that the information constitutes prior art already known to those skilled in the art.

[0006] Summary of the Invention

[0007] In view of this, an object of the present invention is to provide a thrombus removal system and an auxiliary recovery system, which can effectively prevent the fallen thrombus from entering the side branch vessels and distal blood vessels during the withdrawal of the thrombus retriever stent.

[0008] To achieve the above objectives, the present invention provides a thrombus removal system, comprising:

[0009] The thrombus removal device comprises a push-pull guide wire and a thrombus removal stent connected in sequence along its own axis; and

[0010] An auxiliary retrieval system comprises a retrieval catheter, a push-pull device, and a self-expanding stent; the proximal end of the self-expanding stent is connected to the distal end of the push-pull device; the push-pull device is slidably disposed within the retrieval catheter and is used to push and pull the self-expanding stent along the axial direction of the retrieval catheter; the self-expanding stent has a compressed state when delivered within the retrieval catheter and an expanded state after being partially detached from the retrieval catheter;

[0011] The auxiliary retrieval system is used to move along the push-pull guidewire after the thrombus retriever stent captures the target object and is positioned proximal to the thrombus retriever stent, thereby partially separating the self-expanding stent from the retrieval catheter for deployment;

[0012] After capturing the target object, the thrombus removal stent is used to move proximally toward the auxiliary retrieval system under the pull of the push-pull guidewire, and at least partially enter the self-expanding stent through the distal opening of the deployed self-expanding stent for retrieval.

[0013] In one embodiment, after the thrombus retriever stent at least partially enters the self-expanding stent, the thrombus retriever device and the auxiliary retrieval system are used to move together in a proximal direction to enter the outer sheath together, or the thrombus retriever stent moves in a proximal direction and passes through the self-expanding stent into the retrieval catheter.

[0014] In one embodiment, the self-expanding stent is formed of a woven mesh and defines a notch extending therethrough along the axial direction of the self-expanding stent.

[0015] In one embodiment, the braided mesh can be transformed between a curled state and an expanded state, so that the self-expanding stent can adjust its shape according to the size of the lumen in which it is located.

[0016] In one embodiment, the self-expanding stent has a compression section, a tapered section, and a cylindrical support section connected in sequence along its own axis. The compression section is arranged in the retrieval catheter and connected to the push-pull device. The tapered section and the support section can be detached from the retrieval catheter and expanded.

[0017] In one embodiment, a plurality of radiopaque development markers are circumferentially arranged at the proximal edge of the tapered section.

[0018] In one embodiment, the push-pull device includes a push rod, the distal end of which is connected to the proximal end of the self-expanding stent, or the push-pull device includes a push rod and a traction wire, the distal end of which is connected to the proximal end of the self-expanding stent, and the proximal end of the traction wire passes through the push rod and extends to the proximal end of the retrieval catheter.

[0019] In one embodiment, at least a portion of the outer surface of the self-expanding stent is provided with a hydrophilic coating, and / or the inner wall of the distal end of the retrieval catheter is provided with a hydrophilic coating.

[0020] In one embodiment, the thrombus retrieval stent includes a first thrombus retrieval stent, the proximal end of the first thrombus retrieval stent is connected to the distal end of the push-pull guide wire, the first thrombus retrieval stent is a tubular structure composed of a plurality of closed meshes, the closed meshes include a first mesh, a second mesh and a third mesh, the area of ​​the first mesh and the area of ​​the third mesh are both smaller than the area of ​​the second mesh, the first mesh does not overlap with the second mesh and the third mesh, the third mesh is arranged in the second mesh, and at least two of the second meshes cover the outer surface of the first thrombus retrieval stent for at least one circle.

[0021] In one embodiment, the area of ​​the second mesh is 2.5 to 6 times the area of ​​the first mesh.

[0022] In one embodiment, a developer is provided at a position on the first thrombus removal bracket corresponding to the second mesh hole.

[0023] In one embodiment, the first thrombus removal stent includes a proximal portion, a middle portion, and a distal portion connected in sequence, the first meshes are distributed on the proximal portion and the distal portion, the second meshes are distributed on the middle portion, and the area of ​​the first meshes on the distal portion is smaller than the area of ​​the first meshes on the proximal portion.

[0024] In one embodiment, a plurality of the second meshes are distributed on different circumferences of the first thrombus retriever stent, and the second meshes on different circumferences have overlapping portions in the circumferential direction and / or axial direction of the first thrombus retriever stent.

[0025] In one embodiment, the thrombus retrieval stent also includes a second thrombus retrieval stent formed of a densely woven mesh, the distal end of the first thrombus retrieval stent is flexibly connected to the proximal end of the second thrombus retrieval stent, and the second thrombus retrieval stent can block the self-expanding stent at the distal side of the first thrombus retrieval stent after the first thrombus retrieval stent enters the self-expanding stent.

[0026] In one embodiment, the second thrombus retriever stent is used to block the distal opening of the self-expanding stent at the distal exterior of the self-expanding stent, or the second thrombus retriever stent at least partially enters the self-expanding stent for blocking.

[0027] Based on the same inventive concept, the present invention further provides an auxiliary retrieval system, comprising a retrieval catheter, a push-pull device, and a self-expanding stent; the proximal end of the self-expanding stent is connected to the distal end of the push-pull device; the push-pull device is slidably disposed within the retrieval catheter and is used to push and pull the self-expanding stent along the axial direction of the retrieval catheter; the self-expanding stent has a compressed state when delivered within the retrieval catheter and an expanded state after being partially detached from the retrieval catheter;

[0028] The auxiliary retrieval system is used to move along the push-pull guide wire after the thrombus retriever stent captures the target object, and is positioned proximal to the thrombus retriever stent, thereby partially detaching the self-expanding stent from the retrieval catheter and deploying it, and introducing at least a portion of the thrombus retriever stent into the self-expanding stent through the distal opening of the deployed self-expanding stent for retrieval.

[0029] In addition, the present invention also provides a method for removing thrombus using the above-mentioned thrombus removal system, comprising:

[0030] The thrombectomy stent is delivered to the thrombectomy site through an interventional catheter;

[0031] The interventional catheter is removed, allowing the thrombectomy stent to self-expand and capture the thrombus;

[0032] After capturing the thrombus, the retrieval catheter containing the self-expanding stent is moved along the push-pull guidewire until it is positioned proximal to the thrombus retriever stent. The self-expanding stent is then pushed toward the distal end of the retrieval catheter using the push-pull device, allowing the self-expanding stent to expand out of the portion of the retrieval catheter that is free from the retrieval catheter.

[0033] Thereafter, the thrombectomy stent is pulled proximally by pushing and pulling the guidewire until at least a portion of the thrombectomy stent enters the self-expanding stent;

[0034] Subsequently, the thrombectomy device and the auxiliary retrieval system can be withdrawn together, such as withdrawn together into the outer sheath.

[0035] As described above, the present invention provides a thrombus removal system comprising a thrombus retriever device and an auxiliary retrieval system. During the thrombus capture and withdrawal process of the thrombus retriever device, the thrombus retriever stent can be at least partially retracted into the deployed portion of the self-expanding stent of the auxiliary retrieval system. This allows the thrombus retriever stent to be withdrawn from the occlusion site into the retrieval catheter under the protection of the self-expanding stent, effectively preventing dislodged thrombi from entering collateral vessels and distal vessels during the withdrawal process. This improves thrombus removal efficiency and success rate, reduces the risk of secondary stroke, and enhances procedural safety.

[0036] Since the auxiliary recovery system provided in this application and the thrombus removal system provided in this application belong to the same inventive concept, the auxiliary recovery system provided in this application has all the advantages of the thrombus removal system provided in this application, so the beneficial effects of the auxiliary recovery system provided in this application will not be described one by one here. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Those skilled in the art will appreciate that the accompanying drawings are provided for a better understanding of the present invention and do not constitute any limitation on the scope of the present invention.

[0038] FIG1 is a schematic structural diagram of a thrombus removal device according to an embodiment of the present application;

[0039] FIG2 is another schematic structural diagram of the thrombus removal device according to an embodiment of the present application;

[0040] FIG3 is a planar expansion diagram of the first thrombus removal stent in an embodiment of the present application;

[0041] FIG4 is a schematic diagram of the three-dimensional structure of the first thrombus removal stent in an embodiment of the present application;

[0042] FIG5 is a schematic front view of a first thrombus removal stent according to an embodiment of the present application;

[0043] FIG6 is another planar expansion schematic diagram of the first thrombus removal stent in the embodiment of the present application;

[0044] FIG7 is another schematic diagram of the three-dimensional structure of the first thrombus removal stent in the embodiment of the present application;

[0045] FIG8 is a side view of a first thrombus removal stent according to an embodiment of the present application;

[0046] FIG9 is a schematic plan view of the auxiliary recovery system in an initial state according to an embodiment of the present application;

[0047] FIG10 is a schematic plan view of the auxiliary recovery system in the working state according to an embodiment of the present application;

[0048] FIG11 is a partial enlarged schematic diagram of a braided wire having a development mark defined on the proximal edge of the tapered section of the self-expanding stent in an embodiment of the present application;

[0049] FIG12 is a schematic diagram of a planar deployment of a self-expanding stent according to an embodiment of the present application;

[0050] FIG13 is a cross-sectional view of the self-expanding stent in FIG12 at position AA;

[0051] FIG14 is a cross-sectional view of the self-expanding stent in FIG12 at position BB;

[0052] FIG15 is a schematic diagram of the three-dimensional structure of the expandable section of the self-expanding stent in the embodiment of the present application when it is in a released state;

[0053] FIG16 is a schematic structural diagram of a self-expanding stent according to an embodiment of the present application;

[0054] FIG17 is a side view of a self-expanding stent according to an embodiment of the present application;

[0055] Figures 18a to 18d are schematic diagrams of the process of curling and overlapping of the self-expanding stent in an embodiment of the present application;

[0056] 19 to 22 are schematic diagrams showing the steps of removing a thrombus from a patient's blood vessel using the thrombus removal system provided in an embodiment of the present application;

[0057] FIG. 23 is another schematic diagram of the structure of the thrombus removal device according to an embodiment of the present application, which only includes the first thrombus removal bracket.

[0058] In the attached figure:

[0059] 10 - Thrombectomy device; 11 - Push-pull guidewire; 12 - Connecting portion; 13 - Thrombectomy stent; 13A - Stent rod; 130A - First stent rod; 130B - Second stent rod; 130C - Connecting portion between first and second stent rods; 130D - Connecting portion between stent rods of second mesh; 13B - Straight rod; 13C - Tapered closed end; 131 - First thrombectomy stent; 131a - First mesh; 131b - Second mesh; 131c - Third mesh; 132 - Second thrombectomy stent; 14-development ring; 15-structural member; 16-open entrance; 17-overlapping part; 18-free protruding part; 30-auxiliary retrieval system; 31-retrieval catheter; 32-push-pull device; 321-push rod; 322-traction wire; 33-self-expanding stent; 33a-distal opening; 33b-notch; 331-compression section; 332-tapered section; 333-support section; 334-development marker; 100-microcatheter; 101-thrombus; 102-vascular wall; 103-side branch vessel. DETAILED DESCRIPTION

[0060] The following describes the embodiments of the present invention through specific specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in this embodiment only illustrate the basic concept of the present invention in a schematic manner, and the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components during actual implementation. During actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0061] In order to make the objects, advantages and features of the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. The same or similar figure marks in the drawings represent the same or similar parts. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0062] It should be noted that the terms "proximal end" or "proximal side" as used in this application generally refer to the end of a medical device that is closer to the operator when implanted in a human body or animal, while "distal end" or "distal side" refers to the end farther from the operator. "Axial" generally refers to the length of the medical device during delivery, "radial" refers to the direction perpendicular to the medical device's "axial direction," and "circumferential" refers to the direction surrounding the central axis of the medical device itself.

[0063] The core idea of ​​the present invention is to provide a thrombus removal system and an auxiliary recovery system to at least solve the problem in the prior art that thrombi dropped from the thrombus removal stent during the withdrawal process easily enter the side branch vessels and distal vessels.

[0064] The following description refers to the accompanying drawings. Although the following description uses a microcatheter to deliver the thrombectomy device, those skilled in the art will recognize that, in practice, other interventional catheters besides microcatheters can also be used to deliver the thrombectomy device, such as guide catheters. Those skilled in the art will be able to modify the following description to replace the microcatheter with another interventional catheter for delivery.

[0065] With reference to Figures 1 to 23, an embodiment of the present application provides a thrombus removal system, comprising a thrombus removal device 10 and an auxiliary retrieval system 30. The thrombus removal device 10 comprises a push-pull guidewire 11 and a thrombus removal stent 13, which are sequentially connected along the axial direction of the thrombus removal device 10. The push-pull guidewire 11 is a structure having a certain degree of toughness and bending properties, which can push the thrombus removal device 10 to release the thrombus removal device 10 from the microcatheter 100, and can also pull the thrombus removal device 10 when withdrawing the thrombus removal device 10 to store the thrombus removal device 10 in the auxiliary retrieval system 30. In practice, the auxiliary retrieval system 30 can move along the push-pull guidewire 11 to approach or move away from the thrombus removal stent 13.

[0066] Referring to Figures 1 and 2 , in one embodiment, the thrombus retrieval bracket 13 includes a first thrombus retrieval bracket 131 and a second thrombus retrieval bracket 132. As shown in Figure 23 , in another embodiment, the thrombus retrieval bracket 13 includes only the first thrombus retrieval bracket 131. The following description uses the thrombus retrieval device 10 including the first thrombus retrieval bracket 131 and the second thrombus retrieval bracket 132 as an example.

[0067] As shown in Figures 1 and 2, the thrombectomy stent 13 includes a first thrombectomy stent 131 and a second thrombectomy stent 132. The first thrombectomy stent 131 is a tubular structure composed of multiple closed meshes (i.e., the first thrombectomy stent 131 is a tubular structure with meshes), while the second thrombectomy stent 132 is composed of a woven mesh. The proximal end of the first thrombectomy stent 131 is connected to the distal end of the push-pull guidewire 11, and the distal end of the first thrombectomy stent 131 is connected to the proximal end of the second thrombectomy stent 132. Preferably, the distal end of the first thrombectomy stent 131 and the proximal end of the second thrombectomy stent 132 are flexibly connected. The benefits of this flexible connection include enabling the distal end of the first thrombectomy stent 131 and the proximal end of the second thrombectomy stent 132 to swing at a large bending angle, thereby adapting to large curved blood vessel segments and reducing damage to the vessel wall during delivery in tortuous vessels. As can be appreciated, the flexible connection mitigates the interaction between the first and second thrombus retriever stents 131, 132, and reduces damage to the vessels caused by the thrombus retriever device 10 as it navigates through tortuous vessels. Furthermore, the second thrombus retriever stent 132 effectively intercepts escaping thrombi and thrombus fragments, preventing them from drifting toward the collateral vessels 103 and distal vessels.

[0068] Furthermore, when removing a thrombus, the thrombectomy device 10 can be delivered through the microcatheter 100 to the thrombectomy site. The thrombectomy device 10 can have a compressed state, housed within the microcatheter 100, and a fully expanded state, after being pushed out from the distal end of the microcatheter 100. When the thrombectomy device 10 is compressed within the microcatheter 100, its overall volume decreases, allowing it to be placed within the microcatheter 100. The microcatheter 100 is suitable for delivering the compressed thrombectomy device 10 to the thrombectomy site. Once released from the microcatheter 100, the thrombectomy device 10 is freed from the microcatheter 100 and expands on its own.

[0069] Referring to Figures 9 and 10 , the auxiliary retrieval system 30 includes a retrieval catheter 31, a push-pull device 32, and a self-expanding stent 33. The proximal end of the self-expanding stent 33 is connected to the distal end of the push-pull device 32. The retrieval catheter 31 has an inner lumen extending therethrough along its axial direction. The push-pull device 32 is configured to be slidably positioned within the inner lumen of the retrieval catheter 31. The push-pull device 32 is capable of pushing or pulling the self-expanding stent 33 along the axial direction of the retrieval catheter 31, thereby partially disengaging the self-expanding stent 33 from the retrieval catheter 31 or allowing the expanded portion of the self-expanding stent 33 to re-enter the retrieval catheter 31.

[0070] Thus, the self-expanding stent 33 has a compressed state during delivery within the retrieval catheter 31 (see FIG. 9 ), and an expanded state after being partially detached from the retrieval catheter 31 (see FIG. 10 ). Therefore, during the withdrawal of the thrombus retriever 10 after capturing a thrombus, the expanded portion of the self-expanding stent 33 detached from the retrieval catheter 31 can be used to store at least a portion of the stent retriever 13 for retrieval. In other words, the self-expanding stent 33 has an inner lumen through which the stent retriever 13 can pass. After capturing a thrombus, the stent retriever 13 can be stored within the inner lumen of the self-expanding stent 33 or further pass through the inner lumen of the self-expanding stent 33 into the retrieval catheter 31.

[0071] In actual use, the first thrombectomy stent 131 can be entirely housed within the self-expanding stent 33. Furthermore, the second thrombectomy stent 132 can block the distal opening 33a of the self-expanding stent 33 without entering the self-expanding stent 33. Alternatively, the second thrombectomy stent 132 can block the distal opening 33a of the self-expanding stent 33 while partially entering the self-expanding stent 33. Alternatively, the second thrombectomy stent 132 can completely enter the self-expanding stent 33 and block the self-expanding stent 33. Alternatively, the first and second thrombectomy stents 131, 132 can be completely housed within the self-expanding stent 33 and then further passed through the self-expanding stent 33 and into the retrieval catheter 31. In this manner, the second thrombectomy stent 132 can intercept the thrombus distally during the process of thrombus capture and withdrawal by the first thrombectomy stent 131. Furthermore, after the first thrombectomy stent 131 enters the self-expanding stent 33, it can block the self-expanding stent 33 distally of the first thrombectomy stent 131, further preventing the escape of the thrombus. Thus, the second thrombus removal stent 132 can block the distal opening 33a of the self-expanding stent 33 on the distal outside of the self-expanding stent 33 without entering the self-expanding stent 33, or the second thrombus removal stent 132 partially or completely enters the self-expanding stent 33 to block the self-expanding stent 33.

[0072] Regardless of whether there is one or more thrombus retriever stents 13, the auxiliary retrieval system 30 is configured to move along the push-pull guide wire 11 after the microcatheter 100 for delivering the thrombus retriever stent 13 is removed and the thrombus retriever stent 13 captures the thrombus, and is positioned proximal to the thrombus retriever stent 13, and then control the self-expanding stent 33 to partially detach from the retrieval catheter 31 and deploy, and then the thrombus retriever stent 13 that has captured the thrombus moves proximally toward the auxiliary retrieval system 30 under the pull of the push-pull guide wire 11, and at least partially enters the self-expanding stent 33 through the distal opening 33a of the deployed self-expanding stent 33 for deployment.

[0073] 19 to 22 below, to further understand the method and steps of thrombus removal described in this embodiment.

[0074] As shown in FIG19 , the microcatheter 100 containing the thrombus removal device 10 in a compressed state is first delivered to the distal end of the outer sheath (not shown), and the microcatheter 100 is continuously pushed toward the distal end, so that the microcatheter 100 extends out of the distal end of the outer sheath and passes through the gap between the thrombus 101 and the blood vessel wall 102. At this time, the large thrombus 101 is basically located at the position where the first thrombus removal stent 131 is located.

[0075] After the first thrombus removal stent 131 is roughly positioned at the thrombus 101 through the microcatheter 100, as shown in Figure 20, the microcatheter 100 is withdrawn proximally without moving the guide wire 11 until the microcatheter 100 is withdrawn from the body. During the process of withdrawing the microcatheter 100, the thrombus removal device 10 gradually expands and comes into contact with the thrombus 101. During this process, the first thrombus removal stent 131 can capture the thrombus 101.

[0076] After capturing the thrombus, as shown in Figure 21, the retrieval catheter 31 containing the self-expanding stent 33 is pushed as close as possible to the position of the first thrombus removal stent 131 along the push-pull guide wire 11. After positioning, the self-expanding stent 33 is pushed out toward the distal end of the retrieval catheter 31 using the push-pull device 32. Once part of the structure of the self-expanding stent 33 is released and adheres to the blood vessel wall 102, the thrombus removal device 10 is immediately pulled proximally with the help of the push-pull guide wire 11, so that the thrombus removal device 10 moves proximally against the direction of blood flow. At this time, some thrombus fragments may fall off the first thrombus removal stent 131, and the thrombus fragments move toward the second thrombus removal stent 132 along the direction of blood flow. Since the second thrombus removal stent 132 is a woven mesh and adheres to the blood vessel wall 102, the second thrombus removal stent 132 can effectively intercept the fallen thrombus fragments.

[0077] As shown in Figure 22, during the retraction of the thrombus retriever 10, the entire first thrombus retriever stent 131 can be moved into the lumen of the deployed portion of the self-expanding stent 33. At this point, the second thrombus retriever stent 132 does not enter the self-expanding stent 33, but instead serves to seal the distal opening 33a of the self-expanding stent 33. The self-expanding stent 33, thrombus retriever 10, and retrieval catheter 31 are then retracted proximally until they are completely retracted into the outer sheath.

[0078] However, in other cases, the thrombus retriever stent 13 is moved proximally and passed through the self-expanding stent 33 directly into the retrieval catheter 31. For example, the entire thrombus retriever device 10, which has captured the thrombus, is withdrawn directly into the retrieval catheter 31 along the inner lumen of the self-expanding stent 33. At this point, both the first and second thrombus retriever stents 131, 132 are moved into the self-expanding stent 33. The thrombus retriever device 10 is then pulled proximally until it is withdrawn into the retrieval catheter 31. The thrombus retriever device 10 and the auxiliary retrieval system 30 are then inserted into the outer sheath (also known as the sheath) for removal from the patient. In this case, a slightly larger diameter retrieval catheter 31 is required; otherwise, the retrieval catheter 31 may become inaccessible. This operation also protects the thrombus retriever stent 13 during the retrieval process, keeping the captured thrombus within the self-expanding stent 33. This reduces the risk of thrombus dislodging and entering the collateral vessel 103 or distal vessels due to tortuous vessels, plaques, or calcified lesions during the retrieval process.

[0079] Therefore, the thrombectomy stent 13 of this embodiment can be withdrawn from the occlusion site into the retrieval catheter 31 under the protection of the self-expanding stent 33, thereby effectively preventing the thrombus that falls during the withdrawal process from entering the side branch vessel 103 and the distal blood vessel, improving the thrombectomy efficiency and success rate, reducing the risk of secondary stroke, and increasing the safety of the operation.

[0080] The self-expanding stent 33 is primarily composed of a braided mesh, but the present invention does not exclude the possibility of producing the self-expanding stent 33 by cutting from tubular material. The self-expanding stent 33 can be a bare stent (i.e., without a coating) or a coated stent. The self-expanding stent 33 is preferably braided and shaped from metal wire or polymer filaments exhibiting superelasticity and excellent shape memory. The braided mesh self-expanding stent 33 can better protect the retracted thrombectomy stent 13 and prevent thrombus escape during the retraction process.

[0081] Referring to Figures 12-14 and 16-17, the self-expanding stent 33 further defines a notch 33b extending axially therethrough, resulting in the self-expanding stent 33 being entirely composed of an open braided mesh. Furthermore, the braided mesh forming the self-expanding stent 33 is capable of transitioning between a curled state and an extended state, allowing the self-expanding stent 33 to adjust its shape according to the size of the lumen in which it is positioned. This allows the shape of the self-expanding stent 33 to adapt to lumens of varying sizes, such as retrieval catheters 31 of varying specifications and blood vessels of varying sizes. Specifically, when the self-expanding stent 33 is placed into a lumen, it can curl and contract accordingly, partially overlapping the stent, or open the curled, overlapping portion. Thus, the self-expanding stent 33 can adapt to changes in the diameter of the lumen in which it is placed.

[0082] The crimping and contraction process of the self-expanding stent 33 can be seen in Figures 18a to 18d. As can be seen, the larger the diameter of the lumen in which it is used, the less overlap there is, or even no overlap. If the lumen diameter decreases, the self-expanding stent 33 can also be curled and deformed accordingly, creating a partial overlap. This configuration allows the self-expanding stent 33 to be placed in a smaller diameter retrieval catheter 31, allowing it to be used in smaller vessels and delivered deeper into the vessel. Furthermore, the self-expanding stent 33 will curl and overlap when used in smaller vessels, while uncurling and uncurling when used in larger vessels, allowing it to be used in vessels of varying diameters. Furthermore, the self-expanding stent 33 can provide a smaller radial support force, minimizing damage to the vessel wall during withdrawal. However, it should be understood that in other embodiments, the notch 33b may be omitted. Without the notch 33b, the self-expanding stent 33 becomes a circumferentially closed cylindrical structure, still capable of radial contraction and expansion.

[0083] With reference to Figures 10 and 12, in a specific embodiment, the self-expanding stent 33 includes a compression section 331, a tapered section 332, and a cylindrical support section 333, which are sequentially connected along its own axis; the compression section 331 is always arranged in the recovery catheter 31 and is connected to the push-pull device 32; the tapered section 332 and the support section 333 can be separated from the recovery catheter 31 and deployed. The tapered section 332 and the support section 333 constitute an expandable section, which is a superelastic structure and has radial self-expansion properties. The outer diameter of the support section 333 is slightly larger than the diameter of the applied blood vessel, so that it can fit closely with the inner wall of the blood vessel. The tapered section 332 facilitates the self-expanding stent 33 to slide out or be retracted into the recovery catheter 31 smoothly. The tapered section 332 and the support section 333 are connected with a smooth transition. The outer diameter of the support section 333 is equal to the outer diameter of the connection between the support section 333 and the tapered section 332. The outer diameter of the connection between the support section 333 and the tapered section 332 is equal to the maximum outer diameter D2 of the tapered section 332. The outer diameter of the tapered section 332 is greater than the outer diameter of the connection between the tapered section 332 and the compression section 331. The outer diameter of the connection between the tapered section 332 and the compression section 331 is equal to the minimum outer diameter D1 of the tapered section 332. The compression section 331 remains within the confines of the push-pull mechanism 32, ensuring that it remains within the recovery conduit 31.

[0084] As shown in FIG11 , in one embodiment, a developing marker 334 is provided at the proximal edge of the tapered section 332 of the self-expanding stent 33. Preferably, the number of developing markers 334 is multiple, and the multiple developing markers 334 are arranged circumferentially. In this way, during surgery, the operator (medical staff) can accurately locate the position of the self-expanding stent 33 while pushing the self-expanding stent 33, thereby preventing the self-expanding stent 33 from being completely pushed out of the retrieval catheter 31, thereby increasing the safety and reliability of the surgical operation. In a specific embodiment, a plurality of developing markers 334 are defined on the braided wire at the proximal edge of the tapered section 332, and the developing markers 334 can be fixed to the braided wire by physical pressure gripping. Preferably, the multiple developing markers 334 are evenly distributed on the same circumference along the circumference, and the number of developing markers 334 can be 2-8. The material of the developing markers 334 is platinum, gold, iridium, etc., which is not limited by this application.

[0085] Furthermore, at least a portion of the outer surface of the self-expanding stent 33 is provided with a hydrophilic coating. This hydrophilic coating may cover the entire outer surface of the self-expanding stent 33 or only the expandable segment. The hydrophilic coating on the self-expanding stent 33 includes, but is not limited to, polyurethane, and may also be made of other hydrophilic polymer materials. And / or, the distal inner wall of the retrieval catheter 31 is provided with a hydrophilic coating. This hydrophilic coating can reduce the coefficient of friction, facilitating easier removal of the expandable segment from the retrieval catheter 31 and reducing damage to the blood vessel caused by the self-expanding stent 33 during withdrawal. The hydrophilic coating on the distal inner wall of the retrieval catheter 31 includes, but is not limited to, polyvinyl pyrrolidone.

[0086] The present application does not limit the structure of the push-pull device 32. In practice, the push-pull device 32 can push or pull the self-expanding stent 33 in at least one manner.

[0087] As shown in Figures 9 and 10, in one exemplary embodiment, the push-pull device 32 includes a push rod 321 and a pull wire 322. The distal end of the pull wire 322 is connected to the proximal end of the self-expanding stent 33. The proximal end of the pull wire 322 passes through the push rod 321 and extends to the proximal end of the retrieval catheter 31. The proximal end of the pull wire 322 can be connected to the proximal end of the push rod 321 or not, forming a free end when not connected. In this case, the distal end of the push rod 321 is used to abut the proximal end of the self-expanding stent 33 to push the self-expanding stent 33 distally, while the pull wire 322 pulls the self-expanding stent 33 proximally. There is at least one pull wire 322; in this embodiment, there are multiple pull wires 322. More specifically, the proximal end of the compression section 331 is connected to multiple pull wires 322, connected by any one or more methods such as welding, gluing, riveting, and winding.

[0088] In another exemplary embodiment, the push-pull device 32 includes only a push rod 321, the distal end of which is directly or indirectly connected to the proximal end of the self-expanding stent 33. In this case, the self-expanding stent 33 is pushed or pulled directly by the push rod 321. To facilitate connection, the push rod 321 and the self-expanding stent 33 can be connected by a pull wire 322. That is, the proximal end of the self-expanding stent 33 is fixedly connected to the push rod 321 by the pull wire 322.

[0089] The preferred embodiment of the thrombus removal device 10 of this embodiment will be further described below.

[0090] Referring to Figures 1 and 2 , the distal end of the first thrombectomy stent 131 and the proximal end of the second thrombectomy stent 132 are further connected via a connecting portion 12. The connecting portion 12 can connect the distal end of the first thrombectomy stent 131 and the proximal end of the second thrombectomy stent 132 in at least one manner, which is not limited in this application. The connecting portion 12 may or may not be visibly imageable; preferably, the connecting portion 12 is visibly imageable. For example, in one embodiment, the connecting portion 12 is formed from a visibly imageable metal wire that is helically wound axially around the distal end of the first thrombectomy stent 131 and the proximal end of the second thrombectomy stent 132. In another embodiment, the connecting portion 12 is formed from a visibly imageable ring that is crimped to connect the distal end of the first thrombectomy stent 131 and the proximal end of the second thrombectomy stent 132.

[0091] The connection method between the proximal end of the first thrombectomy stent 131 and the distal end of the push-pull guidewire 11 is not limited, and may include winding, extrusion, medical adhesive bonding, laser welding, polymer material fusion welding, etc. As shown in Figure 1, in one embodiment, the proximal end of the first thrombectomy stent 131 and the distal end of the push-pull guidewire 11 are welded or glued. As shown in Figure 2, in another embodiment, the proximal end of the first thrombectomy stent 131 and the distal end of the push-pull guidewire 11 are connected by press-fitting via a developing ring 14.

[0092] As described above, the first thrombus removal stent 131 is a tubular structure formed by connecting a plurality of closed meshes, and each closed mesh is formed by connecting a plurality of stent rods 13A in sequence end to end, as shown in FIG3 for details.

[0093] As shown in Figures 3-4, 7, and 8, in one example, the distal end of the first thrombectomy stent 131 includes a plurality of circumferentially arranged straight rods 13B. These straight rods 13B are converged to form a tapered closed end 13C at the distal end of the first thrombectomy stent 131. This convergent structure of the distal end of the first thrombectomy stent 131 facilitates connection with the proximal end of the second thrombectomy stent 132.

[0094] As shown in Figures 1 and 2 , in one exemplary embodiment, the distal end of the second thrombectomy stent 132 is constrained into a tapered shape. The distal end of the second thrombectomy stent 132 is gathered and secured by a structural member 15 to prevent the braided wire at the distal end from unraveling. Structural member 15 can be a cannula, preferably a radiographic cannula. The proximal end of the second thrombectomy stent 132 is coaxial with the distal end of the first thrombectomy stent 131.

[0095] The first thrombectomy stent 131 can be made of a metal alloy or polymer material with superelasticity and excellent shape memory, preferably a nickel-titanium alloy. The first thrombectomy stent 131 can be cut from a tube and then heat-set, but this is not limited to this. The closed mesh in the first thrombectomy stent 131 can have any shape, such as a regular shape like a rhombus or pentagon, or an irregular shape, without limitation. The specific length and radial dimensions of the first thrombectomy stent 131 after deployment can be determined based on the diameter of the target vessel and the length of the thrombus. Optionally, the axial length of the first thrombectomy stent 131 when fully deployed is 13 mm to 50 mm, and the maximum radial width is 2.0 mm to 6.0 mm. Optionally, the width of the stent rod 13A is 0.06 mm to 0.12 mm; designing the first thrombectomy stent 131 according to these dimensions can effectively balance support force and radial dimensions.

[0096] Furthermore, the closed mesh structure of the first thrombectomy stent 131 has been improved. Specifically, as shown in Figure 3, the closed mesh structure of the first thrombectomy stent 131 includes a first mesh 131a, a second mesh 131b, and a third mesh 131c. The areas of the first mesh 131a and the third mesh 131c are both smaller than the area of ​​the second mesh 131b. The first mesh 131a does not overlap with the second mesh 131b and the third mesh 131c, and the third mesh 131c is disposed within the second mesh 131b. At least two second meshes 131b cover at least one circle of the outer surface of the first thrombectomy stent 131. Thus, the first thrombectomy stent 131 utilizes a multi-mesh hybrid design. This structure enables the first thrombectomy stent 131 to effectively remove both soft and hard thrombi, further improving the efficiency and success rate of thrombectomy. Specifically, the first mesh 131a has a smaller area, making it easier to embed into a soft thrombus. The second mesh 131b forms an open entrance 16 with a larger area, allowing both hard and soft thrombi to be embedded or embedded into the lumen of the first thrombus removal stent 131 through these open entrances 16. At the same time, the third mesh 131c can form a spatial warping structure in the second mesh 131b, thereby suppressing the thrombus in the second mesh 131b from falling off or escaping, thereby further reducing the risk of thrombus falling off or escaping.

[0097] The first thrombectomy stent 131 comprises a proximal portion 1311, a middle portion 1312, and a distal portion 1313, which are connected in sequence. Furthermore, a plurality of first meshes 131a are distributed throughout the proximal portion 1311 and the distal portion 1313. The first meshes 131a can be evenly or unevenly distributed throughout the first thrombectomy stent 131, preferably evenly distributed. The first meshes 131a are distributed both axially and circumferentially along the first thrombectomy stent 131. The first meshes 131a provide a certain radial support force, making it easier for the stent rod 13A to embed into a soft thrombus. Furthermore, the first meshes 131a in the distal portion 1313 of the first thrombectomy stent 131 can also provide a certain degree of thrombus interception. The area (i.e., size) of the first mesh 131a on the distal portion 1313 and the area of ​​the first mesh 131a on the proximal portion 1311 can be the same or different. Preferably, the first mesh 131a on the distal portion 1313 has a smaller area than the first mesh 131a on the proximal portion 1311. In this way, the first mesh 131a on the distal portion 1313 can better intercept the thrombus in the lumen of the first thrombus retriever stent 131. Optionally, the area of ​​the first mesh 131a is 0.7 mm. 2 -4.0mm 2 .

[0098] The area of ​​the second mesh 131b is significantly larger than that of the first mesh 131a. Here, "significantly larger" means that the area of ​​the second mesh 131b is at least 2.5 times the area of ​​the first mesh 131a. The specific multiple can be determined by those skilled in the art based on practical needs and is not limited here. Preferably, the area of ​​the second mesh 131b is 2.5 to 6 times the area of ​​the first mesh 131a. Furthermore, several second meshes 131b are distributed throughout the middle portion 1312, precisely located where thrombi are likely to accumulate.

[0099] Referring to Figures 5 and 7 , the plurality of second meshes 131b can form a plurality of relatively large open inlets 16 on the outer surface of the first thrombus retriever stent 131. Due to the large size of the open inlets 16, most hard thrombi and large soft thrombi can be embedded within them, or even pass completely through them into the lumen of the first thrombus retriever stent 131, thus reducing the contact surface between the thrombi and the vessel wall. Furthermore, during the retrieval process, large, intact soft thrombi become embedded within the open inlets 16, while small, fragmented soft thrombi and hard thrombi pass completely through the second meshes 131b into the lumen of the first thrombus retriever stent 131, move relative to the first thrombus retriever stent 131, and then become free and enter the distal end of the first thrombus retriever stent 131. Since the mesh density of the first mesh 131a on the distal portion 1313 is greater than the mesh density at the open entrance 16 (i.e., the second mesh 131b), the contact area between the thrombus and the distal end of the first thrombus removal bracket 131 increases, and the friction coefficient also increases, so that the thrombus can adhere to the inner wall of the distal end of the first thrombus removal bracket 131, achieving an interception effect.

[0100] It should be noted that the number of open inlets 16 is no less than 2, and preferably ranges from 2 to 6. At least two open inlets 16 are spaced apart on the outer surface of the first thrombus removal stent 131 . Each open inlet 16 comprises a second mesh 131 b and communicates with the inner lumen of the first thrombus removal stent 131 .

[0101] Furthermore, the plurality of second meshes 131b are distributed along different circumferences of the first thrombectomy stent 131. The second meshes 131b on different circumferences overlap circumferentially and / or axially with respect to the first thrombectomy stent 131. This reduces blind spots during thrombectomy and increases the probability of successfully capturing large and hard thrombi with a single release of the thrombectomy stent 131, thereby improving thrombectomy efficiency, shortening surgical time, and alleviating patient pain. Specifically, when viewed from one end of the thrombectomy device 10 toward the other, the plurality of second meshes 131b overlap. That is, when any second mesh 131b is translated along the axial direction of the thrombectomy device 10 toward another second mesh 131b, the second meshes 131b always partially intersect at a certain position along the circumferential direction of the thrombectomy device 10, and one second mesh 131b always partially covers another second mesh 131b. When any second mesh 131b is translated along the axial direction of the thrombus removal device 10 toward another second mesh 131b, these second meshes 131b partially intersect at least at a certain position in the circumferential direction of the thrombus removal device 10, and the intersecting portion is the overlapping portion.

[0102] For easier understanding, please refer to the planar expansion diagram of the first thrombectomy stent 131 shown in FIG3 . For example, in the case of two second meshes 131b defined on each circumference, when viewed from one end of the first thrombectomy stent 131 toward the other, the second meshes 131b on the distal circumference overlap with the second meshes 131b on the proximal circumference 17 (the area defined by the dashed line). Furthermore, one second mesh 131b on one circumference overlaps with two adjacent second meshes 131b on another circumference. In other words, the second meshes 131b on different circumferences overlap in both the circumferential and axial directions of the first thrombectomy stent 131.

[0103] Preferably, the open inlets 16 are evenly distributed circumferentially and axially on the first thrombectomy stent 131. The multiple open inlets 16 on the first thrombectomy stent 131 substantially cover the entire outer wall of the stent 131, and the open inlets 16 are continuously arranged within the range corresponding to the thrombectomy length. This significantly reduces blind spots during thrombectomy. During thrombectomy, regardless of the location of contact between the thrombus and the outer wall of the fully deployed first thrombectomy stent 131, a large thrombus can always be inserted into the lumen of the first thrombectomy stent 131 through one of the open inlets 16 on the outer wall. This reduces translational and rotational operations and improves thrombectomy efficiency. The circumferential length L of each second mesh aperture 131b is approximately half the circumference of the first thrombectomy stent 131, and at least two second mesh apertures 131b circumferentially cover the entire outer surface of the first thrombectomy stent 131.

[0104] Furthermore, the third mesh 131c can be formed by providing a free protrusion 18 extending from one stent rod 13A into the second mesh 131b within the second mesh 131b. This free protrusion 18 forms a closed mesh structure and forms the third mesh 131c. The free protrusion 18 can be formed by extending from the stent rod 13A at the proximal end of the second mesh 131b into the distal end of the second mesh 131b, or by extending from the stent rod 13A at the distal end of the second mesh 131b into the proximal end of the second mesh 131b. In this way, during the deployment process after the thrombus removal device 10 is released, the thrombus can enter the cavity of the first thrombus removal bracket 131 from the outer area of ​​the third mesh 131c within the second mesh 131b. When the thrombus removal device 10 is withdrawn, the free protrusion 18 constituting the third mesh 131c has the function of preventing the thrombus from detaching from the second mesh 131b again, which is beneficial for the thrombus removal device 10 to stabilize the thrombus when it moves in the tortuous blood vessel and reduce the risk of thrombus detachment.

[0105] The area of ​​the third mesh 131c defined by the free protrusion 18 is also much smaller than that of the second mesh 131b. It is understood that the third mesh 131c has a support rod 13A independent of the second mesh 131b. The support rods 13A of the third mesh 131c include a first support rod 130A and a second support rod 130B. One end of each of the first support rod 130A and the second support rod 130B is connected to the support rod 13A of the second mesh 131b. The other ends of the first support rod 130A and the second support rod 130B are connected to each other to form a free protrusion 18 extending toward the distal end or the proximal end. See FIG5 for details.

[0106] The length of the third mesh 131c should not affect the entry of thrombus (especially large thrombus) into the lumen of the first thrombus removal stent 131. Optionally, the axial length of the third mesh 131c is 1 / 4-1 / 2 of the axial length of the second mesh 131b.

[0107] Furthermore, in order to accurately locate the position of the second mesh 131b, a developer (not marked) is provided on the first thrombus removal bracket 131 at the position corresponding to the second mesh 131b, so that the contact between the first thrombus removal bracket 131 and the vascular thrombus can be clearly judged based on the development of the developer under X-ray. By moving or rotating the thrombus removal device 10, the second mesh 131b can be accurately aligned with the large thrombus, thereby improving the thrombus removal efficiency.

[0108] In one embodiment, as shown in Figures 3 and 5, a groove is provided at the connection portion 130C between the two support rods 130A and 130B of the third mesh 131c, and a developer is placed in the groove. In another embodiment, as shown in Figure 6, a groove is provided at the connection portion 130D between the two support rods 13A of the adjacent second mesh 131b, and a developer is placed in the groove. The shape of the groove is not limited, and for ease of processing, a circular groove is preferably selected. In other embodiments, a developer can be formed by winding a developer wire around the support rod 13A of the second mesh 131b, such as one or more developer wires attached to the support rod 13A of the second mesh 131b in a spirally wound manner. The material of the developer is not particularly limited, and includes but is not limited to radiopaque metal developer materials such as platinum, gold, platinum-iridium, and tantalum.

[0109] In this way, during the process of withdrawing the microcatheter 100, the thrombus removal device 10 gradually expands and comes into contact with the thrombus 101. At this time, the position of the developer at the second mesh 131b can be observed by an imaging device to observe whether the large thrombus 101 has completely entered the cavity of the first thrombus removal bracket 131. If necessary, the thrombus removal device 10 can be moved axially or rotated at a small angle to ensure that the thrombus 101 enters the open entrance 16.

[0110] Furthermore, the second thrombectomy stent 132 can be woven from metal wires or polymer filaments exhibiting superelasticity and excellent shape memory. After being woven and formed, it is heat-treated in a mold to achieve a woven mesh of the desired shape and size. Preferably, the second thrombectomy stent 132 is woven from a mixture of memory alloy wires and radiopaque precious metal wires to facilitate the physician's determination of the second thrombectomy stent 132's position within the vessel, thereby improving surgical efficiency and accuracy.

[0111] The second thrombectomy stent 132 is a mesh disc structure. While its specific shape is not limited, it should be chosen to minimize contact area with the vessel's inner wall, such as a sphere, disc, or basket. During use, after deployment, the second thrombectomy stent 132 makes contact with the vessel's inner wall, preferably in a linear fashion. This minimizes contact area and causes minimal damage to the vessel. Compared to the first thrombectomy stent 131, the second thrombectomy stent 132 has a denser closed mesh, thus allowing it to intercept thrombus fragments released by the first thrombectomy stent 131 during thrombectomy.

[0112] Preferably, the diameter of the braided wire in the second thrombus retriever stent 132 is smaller than the width of the stent rod 13A in the first thrombus retriever stent 131. Since the second thrombus retriever stent 132 primarily serves as an interceptor, it does not require a large radial support force. Therefore, a relatively fine braided wire is used to form a dense mesh. However, if the mesh is too dense, the second thrombus retriever stent 132 may be difficult to compress and retract into the microcatheter 100, and thrombus fragments attached to the second thrombus retriever stent 132 may be easily scraped off by the catheter. To address this problem, the braided wire used to prepare the second thrombus retriever stent 132 preferably has a diameter of 0.02mm-0.12mm and a mesh area of ​​0.05mm. 2 -1mm 2 .

[0113] In summary, compared with the prior art, the auxiliary recovery system and thrombus removal system provided by the present invention have at least the following advantages:

[0114] (1) In the assisted retrieval system of the present invention, the self-expanding stent can cooperate with the thrombectomy device. During the thrombectomy device's withdrawal process after capturing the thrombus, the thrombectomy device can be at least partially pulled into the self-expanding stent. Thus, the thrombectomy device can be withdrawn from the occluded site into the retrieval catheter under the protection of the self-expanding stent. This can effectively prevent thrombi that fall or dislodge during the withdrawal process from entering collateral vessels and distal vessels, thereby improving the efficiency and success rate of thrombectomy, reducing the risk of secondary stroke, and increasing surgical safety.

[0115] Therefore, the thrombectomy device is withdrawn under the protection of the self-expanding stent, which can better prevent the thrombus from falling off and entering the side branch vessels and distal vessels during the withdrawal process.

[0116] (2) The self-expanding stent is provided with a notch extending along its axial direction, so that the external dimensions of the self-expanding stent can adapt to the diameter of the lumen, such as adapting to different specifications of retrieval catheters and different sizes of blood vessels, thereby increasing the scope of application of the self-expanding stent and making the application of the auxiliary retrieval system more flexible and convenient. In this way, when the self-expanding stent is placed in the lumen, the self-expanding stent can be curled and contracted accordingly to partially overlap, or the curled and overlapped part can be opened. With this structure, on the one hand, the self-expanding stent can be placed in a retrieval catheter with a smaller diameter, so that it can be used in a smaller diameter blood vessel and delivered to a deeper part of the blood vessel. On the other hand, the self-expanding stent will curl and overlap when used in a blood vessel with a smaller lumen, and will open the "curled and overlapped" state when used in a blood vessel with a larger lumen, so that it can be applied to blood vessels of different diameters. On the other hand, the self-expanding stent can also provide a smaller radial support force, which will cause less damage to the inner wall of the blood vessel when withdrawn.

[0117] (3) In the thrombus removal device of the present invention, the first thrombus removal stent adopts a multi-mesh hybrid design. This structure enables the first thrombus removal stent to effectively remove both soft and hard thrombi, further improving the efficiency and success rate of thrombus removal. Specifically, the first mesh has a small area, which facilitates insertion into soft thrombi. The second mesh forms a larger open entrance, allowing both hard and soft thrombi to be inserted or embedded into the lumen of the first thrombus removal stent through these open entrances. At the same time, the third mesh forms a spatially warped structure within the second mesh, thereby preventing thrombi in the second mesh from falling off or escaping.

[0118] (4) The second mesh in the first thrombectomy stent has overlapping parts in both the circumferential and axial directions. This distribution can reduce the blind area of ​​thrombectomy and increase the probability of successfully capturing large thrombi and hard thrombi by releasing the thrombectomy stent once, thereby improving the efficiency of thrombectomy, shortening the operation time, and reducing the pain of patients.

[0119] (5) The first thrombus removal stent is provided with a developing mark at the position corresponding to the second mesh hole, so as to facilitate the development of the developing mark under X-ray and accurately locate the position of the second mesh hole, thereby ensuring that a large thrombus can be embedded in or enter the cavity of the first thrombus removal stent.

[0120] (6) The thrombus removal device of the present invention may further include a second thrombus removal stent. The second thrombus removal stent is made of a woven dense mesh, which can be used in conjunction with the first thrombus removal stent to effectively intercept escaping thrombi and thrombus fragments.

[0121] Finally, it should be noted that, as discussed herein, a "target object" can be any form of obstruction, such as a soft red thrombus, a hard white thrombus, or other forms of clot. Furthermore, a "patient" or "individual" can be a human or any animal. It should be understood that the animal can be any suitable type, including but not limited to mammals, veterinary animals, livestock animals, or pets. For example, the animal can be a laboratory animal specifically selected to have certain characteristics similar to those of humans (e.g., rats, dogs, pigs, monkeys, etc.).

[0122] The above description is only a description of the preferred embodiment of the present invention and does not limit the scope of the present invention. Any changes and modifications made by ordinary technicians in the field of the present invention based on the above disclosure are within the scope of protection of the technical solution of the present invention.

Claims

1. A thrombus removal system, characterized in that: include: The thrombus removal device comprises a push-pull guide wire and a thrombus removal bracket which are sequentially connected along the axial direction of the device; as well as, An auxiliary retrieval system comprises a retrieval catheter, a push-pull device and a self-expanding stent; the proximal end of the self-expanding stent is connected to the distal end of the push-pull device; the push-pull device is used to be slidably placed in the retrieval catheter and to push and pull the self-expanding stent along the axial direction of the retrieval catheter; the self-expanding stent has a compressed state when delivered in the retrieval catheter and an expanded state after being partially separated from the retrieval catheter; The auxiliary retrieval system is used to move along the push-pull guide wire after the thrombus retriever stent captures the target object, and is positioned proximal to the thrombus retriever stent, thereby partially detaching the self-expanding stent from the retrieval catheter for deployment; After capturing the target object, the thrombus removal stent is used to move proximally toward the auxiliary retrieval system under the pull of the push-pull guidewire, and at least partially enter the self-expanding stent through the distal opening of the deployed self-expanding stent for retrieval.

2. The thrombus removal system according to claim 1, characterized in that: After the thrombus retriever stent at least partially enters the self-expanding stent, the thrombus retriever device and the auxiliary retrieval system are used to move together in the proximal direction to enter the outer sheath together, or the thrombus retriever stent moves in the proximal direction and passes through the self-expanding stent into the retrieval catheter.

3. The thrombus removal system according to claim 1 or 2, characterized in that: The self-expanding stent is made of a braided mesh and defines a notch extending through the self-expanding stent in the axial direction.

4. The thrombus removal system according to claim 3, characterized in that: The braided mesh can be transformed between a curled state and a stretched state, so that the self-expanding stent can adjust its shape according to the size of the lumen in which it is located.

5. The thrombus removal system according to claim 4, characterized in that: The self-expanding stent includes a compression section, a tapered section and a cylindrical support section which are sequentially connected along its own axis. The compression section is arranged in the recovery catheter and connected to the push-pull device. The tapered section and the support section can be separated from the recovery catheter and deployed.

6. The thrombus removal system according to claim 5, characterized in that: A plurality of radiopaque development marks are circumferentially arranged at the proximal edge of the tapered section.

7. The thrombus removal system according to claim 1 or 2, characterized in that: The push-pull device includes a push rod, the distal end of which is connected to the proximal end of the self-expanding stent, or the push-pull device includes a push rod and a traction wire, the distal end of which is connected to the proximal end of the self-expanding stent, and the proximal end of the traction wire passes through the push rod and extends to the proximal end of the retrieval catheter.

8. The thrombus removal system according to claim 1 or 2, characterized in that: At least a portion of the outer surface of the self-expanding stent is provided with a hydrophilic coating, and / or a distal inner wall of the retrieval catheter is provided with a hydrophilic coating.

9. The thrombus removal system according to claim 1 or 2, characterized in that: The thrombus retrieval bracket includes a first thrombus retrieval bracket, the proximal end of the first thrombus retrieval bracket is connected to the distal end of the push-pull guide wire, the first thrombus retrieval bracket is a tubular structure composed of a plurality of closed meshes, the closed meshes include a first mesh, a second mesh and a third mesh, the area of ​​the first mesh and the area of ​​the third mesh are both smaller than the area of ​​the second mesh, the first mesh does not overlap with the second mesh and the third mesh, the third mesh is arranged in the second mesh, and at least two of the second meshes cover the outer surface of the first thrombus retrieval bracket by at least one circle.

10. The thrombus removal system according to claim 9, characterized in that: The area of ​​the second mesh is 2.5 to 6 times the area of ​​the first mesh.

11. The thrombus removal system according to claim 9, characterized in that: A developer is disposed on the first thrombus removal bracket at a position corresponding to the second mesh hole.

12. The thrombus removal system according to claim 9, characterized in that: The first thrombus removal bracket includes a proximal portion, a middle portion and a distal portion connected in sequence, the first meshes are distributed on the proximal portion and the distal portion, the second meshes are distributed on the middle portion, and the area of ​​the first meshes on the distal portion is smaller than the area of ​​the first meshes on the proximal portion.

13. The thrombus removal system according to claim 9, characterized in that: A plurality of the second meshes are distributed on different circumferences of the first thrombus retriever stent, and the second meshes on different circumferences have overlapping portions in the circumferential direction and / or axial direction of the first thrombus retriever stent.

14. The thrombus removal system according to claim 9, characterized in that: The thrombus retrieval stent also includes a second thrombus retrieval stent formed of a densely woven mesh. The distal end of the first thrombus retrieval stent is flexibly connected to the proximal end of the second thrombus retrieval stent. The second thrombus retrieval stent can block the self-expanding stent at the distal side of the first thrombus retrieval stent after the first thrombus retrieval stent enters the self-expanding stent.

15. The thrombus removal system according to claim 14, characterized in that: The second thrombus retrieval stent is used to block the distal opening of the self-expanding stent at the distal exterior of the self-expanding stent, or the second thrombus retrieval stent at least partially enters the self-expanding stent for blocking.

16. An auxiliary recovery system, characterized in that: The invention comprises a retrieval catheter, a push-pull device and a self-expanding stent; the proximal end of the self-expanding stent is connected to the distal end of the push-pull device; the push-pull device is used to be slidably placed in the retrieval catheter and to push and pull the self-expanding stent along the axial direction of the retrieval catheter; the self-expanding stent has a compressed state when delivered in the retrieval catheter and an expanded state after being partially separated from the retrieval catheter; The auxiliary retrieval system is used to move along the push-pull guide wire after the thrombectomy stent captures the target object, and is positioned proximal to the thrombectomy stent, thereby allowing the self-expanding stent to partially detach from the retrieval catheter and be deployed, and at least a portion of the thrombectomy stent is introduced into the self-expanding stent through the distal opening of the deployed self-expanding stent for retrieval.

17. The auxiliary recovery system according to claim 16, characterized in that: The self-expanding stent is made of a braided mesh and defines a notch extending through the self-expanding stent in the axial direction.

18. The auxiliary recovery system according to claim 17, characterized in that: The braided mesh can be transformed between a curled state and a stretched state, so that the self-expanding stent can adjust its shape according to the size of the lumen in which it is located.

Images