CN221083730U

CN221083730U - Thrombus removal system and auxiliary recovery system

Info

Publication number: CN221083730U
Application number: CN202321987308.0U
Authority: CN
Inventors: 耿康康; 周奇; 武金田; 黄海勇
Original assignee: Shanghai Microport Medical Group Co Ltd
Current assignee: Shanghai Microport Medical Group Co Ltd
Priority date: 2023-07-26
Filing date: 2023-07-26
Publication date: 2024-06-07
Anticipated expiration: 2033-07-26

Abstract

The utility model relates to a thrombus removal system and an auxiliary recovery system. The thrombus removal system includes: the thrombus taking device comprises a push-pull guide wire and a thrombus taking bracket which are sequentially connected along the axial direction of the thrombus taking device; the auxiliary recovery system comprises a recovery catheter, a push-pull device and a self-expansion bracket; the proximal end of the self-expanding stent is connected with 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-expanding bracket along the axial direction of the recovery catheter; the self-expanding stent has a compressed state when delivered within the retrieval catheter and a deployed state after partially exiting the retrieval catheter; the auxiliary recovery system is used for moving along the push-pull guide wire to be positioned at the proximal side of the thrombus taking support, so that the self-expansion support is partially separated from the recovery catheter to be unfolded, the thrombus taking support is pulled by the push-pull guide wire to move proximally to at least partially enter the self-expansion support after capturing a target object, the thrombus taking support is retracted under the protection of the self-expansion support, and thrombus is prevented from entering side branches and blood vessels at the distal end.

Description

Thrombus removal system and auxiliary recovery system

Technical Field

The utility model relates to the field of medical instruments, in particular to a thrombus removal system and an auxiliary recovery system.

Background

Embolization refers to the phenomenon in which abnormal substances insoluble in blood appear in circulating blood and flow with the blood, thereby blocking the lumen of a blood vessel. When a thrombus occurs in a coronary artery, a patient may have symptoms such as sudden chest pain or discomfort, shortness of breath, sweating, dizziness, nausea, vomiting, etc., thereby causing myocardial ischemia and myocardial infarction. When a thrombus occurs in the cerebrovascular system to block cerebral blood flow, the patient can produce symptoms such as sudden severe headache, dizziness, aphasia, limb weakness or numbness, blurred vision, blindness or double vision, facial numbness or sagging, consciousness disturbance, coma and the like, thereby causing ischemic necrosis of local brain tissues.

Thrombus in the cranium or coronary is typically hard, but may also be soft or semi-hard and semi-soft. Fresh thrombi are softer and also easily dissolved, so-called red thrombi, which are generally soft and brittle. Over time, platelets and fibrin will gradually bind together, so that the thrombus becomes increasingly hard, forming a so-called white thrombus, which is rich in fibers, strong in viscoelasticity, and difficult to compress. The stent thrombus taking is a common mechanical thrombus taking mode, and the method can quickly recanalize the occluded blood vessel and improve the recanalization rate of the blood vessel. At present, most of thrombus taking brackets are of self-expanding structures, the thrombus taking brackets are compressed and placed in micro-catheters before being used, the micro-catheters penetrate through thrombus during use, then the micro-catheters are retracted, the thrombus taking brackets are self-expanded and unfolded in an unbound state, in the process, the bracket rods are gradually embedded into the thrombus or the thrombus penetrates through the bracket rods to enter the inner cavity of the thrombus taking brackets, then the guide wires are pulled towards the proximal end, and the thrombus taking brackets and the thrombus are taken in the recovery catheters.

However, the current thrombus removing stent is not ideal in terms of thrombus removal, and particularly has poor thrombus removing effect in intracranial and coronary vessels. Intracranial and coronary vessels are more tortuous and may have plaque or calcified lesions, the difficulty of thrombus removal is high, and the thrombus removal stent is withdrawn from the occlusion site into the recovery catheter, which requires a longer distance, during which the red soft thrombus is liable to break, and the formed thrombus fragments are liable to escape to the blood vessels at the far end to form new embolism. In particular, there are many side branch vessels in the cranium, in particular in the coronary vessels, from which thrombus may fall during withdrawal of the thrombus-taking stent into the side branch vessels and the distal vessels, thereby causing new embolism in the coronary, even endangering the life of the patient.

It should be noted that the information disclosed in the background section of the present application is only for enhancement of understanding of the general background of the present application and should not be taken as an admission or any form of suggestion that this information forms the prior art already known to those skilled in the art.

Disclosure of utility model

Accordingly, it is an object of the present utility model to provide a thrombi removal system and an auxiliary recovery system that can effectively prevent falling thrombi from entering side branch vessels and distal vessels during retraction of a thrombus removal stent.

To achieve the above object, the present utility model provides a thrombus removal system comprising:

The thrombus taking device comprises a push-pull guide wire and a thrombus taking bracket which are sequentially connected along the axial direction of the thrombus taking device; and

The auxiliary recovery system comprises a recovery catheter, a push-pull device and a self-expansion bracket; the proximal end of the self-expanding stent is connected with the distal end of the push-pull device; the push-pull device is slidably arranged in the recovery catheter and is used for pushing and pulling the self-expanding bracket along the axial direction of the recovery catheter; the self-expanding stent has a compressed state when delivered within the retrieval catheter and a deployed state after partially disengaging the retrieval catheter;

The auxiliary recovery system is used for moving along the push-pull guide wire after the target object is captured by the thrombus taking bracket and is positioned at the near side of the thrombus taking bracket, so that the self-expansion bracket is partially separated from the recovery catheter to be unfolded;

The thrombus-taking stent is used for moving towards the direction of the auxiliary recovery system under the pulling of the push-pull guide wire after capturing the target object, and at least partially enters the self-expansion stent for recovery through a distal opening of the self-expansion stent which is unfolded.

In one embodiment, after the embolic stent is at least partially advanced into the self-expanding stent, the embolic device and the auxiliary retrieval system are adapted to be moved together in a proximal direction to advance together into the outer sheath, or the embolic stent is moved in a proximal direction and advanced through the self-expanding stent into the retrieval catheter.

In one embodiment, the self-expanding stent is formed of a woven mesh and defines a notch extending therethrough in an axial direction of the self-expanding stent.

In one embodiment, the mesh is transformable between a crimped state and a deployed state such that the self-expanding stent is capable of adjusting morphology according to the size of the lumen in which it is positioned.

In one embodiment, the self-expanding stent is provided with a compression section, a conical section and a cylindrical supporting section which are sequentially connected along the axial direction of the self-expanding stent, wherein the compression section is arranged in the recovery catheter and is connected with the push-pull device, and the conical section and the supporting section can be separated from the recovery catheter to be unfolded.

In one embodiment, a plurality of radiopaque development markers are circumferentially disposed at the proximal edge of the tapered section.

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

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 distal wall of the recovery catheter is provided with a hydrophilic coating.

In one embodiment, the thrombus removing support comprises a first thrombus removing support, the proximal end of the first thrombus removing support is connected with the distal end of the push-pull guide wire, the first thrombus removing support is of a net tubular structure formed by a plurality of closed meshes, the closed meshes comprise a first mesh, a second mesh and a third mesh, the areas of the first mesh and the third mesh are smaller than those of the second mesh, the first mesh is non-overlapped relative to the second mesh and the third mesh, the third mesh is arranged in the second mesh, and at least two second meshes cover the outer surface of the first thrombus removing support at least one circle.

In one embodiment, the area of the second mesh is 2.5 to 6 times that of the first mesh.

In one embodiment, a developer is disposed on the first thrombus removing stand at a position corresponding to the second mesh.

In one embodiment, the first thrombus-taking scaffold comprises a proximal end portion, a middle portion and a distal end portion which are sequentially connected, wherein the first meshes are distributed on the proximal end portion and the distal end portion, the second meshes are distributed on the middle portion, and the area of the first meshes on the distal end portion is smaller than that of the first meshes on the proximal end portion.

In one embodiment, a plurality of the second mesh openings are distributed on different circumferences of the first thrombolytic stent, and the second mesh openings on different circumferences have overlapping portions in the circumferential direction and/or the axial direction of the first thrombolytic stent.

In one embodiment, the thrombus removing stent further comprises a second thrombus removing stent formed by a woven dense net, wherein the distal end of the first thrombus removing stent is flexibly connected with the proximal end of the second thrombus removing stent, and the second thrombus removing stent can seal the self-expanding stent on the distal side of the first thrombus removing stent after the first thrombus removing stent enters the self-expanding stent.

In one embodiment, the second thrombectomy stent is used to block a distal opening of the self-expanding stent distally outside the self-expanding stent, or the second thrombectomy stent is at least partially advanced into the self-expanding stent for occlusion.

Based on the same inventive concept, the utility model also provides an auxiliary recovery system, which comprises a recovery catheter, a push-pull device and a self-expansion bracket; the proximal end of the self-expanding stent is connected with 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-expanding bracket along the axial direction of the recovery catheter; the self-expanding stent has a compressed state when delivered within the retrieval catheter and a deployed state after partially disengaging the retrieval catheter;

The auxiliary recovery system is used for moving along a push-pull guide wire after a target object is captured by the thrombus taking support and is positioned at the near side of the thrombus taking support, so that the self-expansion support is partially separated from the recovery catheter to be unfolded, and at least part of the thrombus taking support is guided into the self-expansion support through a distal opening of the unfolded self-expansion support to be recovered.

As described above, in the present utility model, there is provided a thrombus removal system comprising a thrombus removal device and an auxiliary retrieval system, wherein the thrombus removal stent can be at least partially received into the deployed portion of the self-expanding stent of the auxiliary retrieval system during retraction of the thrombus captured by the thrombus removal device. So, make the thrombus of taking out support can be under the protection of self-expanding support follow the position of blocking and withdraw in retrieving the pipe to prevent effectively that the thrombus that drops in the withdrawal process from getting into side branch vessel and distal end blood vessel, and then improve and take out efficiency and thrombus success rate, and reduce secondary apoplexy risk, and increase operation security.

Because the auxiliary recovery system provided by the application and the thrombus removal system provided by the application belong to the same application conception, the auxiliary recovery system provided by the application has all the advantages of the thrombus removal system provided by the application, and the beneficial effects of the auxiliary recovery system provided by the application are not repeated one by one.

Drawings

Those of ordinary skill in the art will appreciate that the figures are provided for a better understanding of the present utility model and do not constitute any limitation on the scope of the present utility model. Wherein:

FIG. 1 is a schematic view of a thrombus removal device according to an embodiment of the present application;

FIG. 2 is a schematic view of another embodiment of a thrombus removal device according to the present application;

FIG. 3 is a schematic plan view of a first stent graft according to an embodiment of the present application;

FIG. 4 is a schematic perspective view of a first thrombolytic stent according to an embodiment of the present application;

FIG. 5 is a schematic front view of a first embolectomy bracket according to an embodiment of the present application;

FIG. 6 is another schematic plan view of a first stent graft according to an embodiment of the present application;

FIG. 7 is a schematic view showing another perspective structure of the first thrombolytic stent according to the embodiment of the present application;

FIG. 8 is a schematic side view of a first thrombolytic stent according to an embodiment of the present application;

FIG. 9 is a schematic plan view of an auxiliary recovery system in an initial state according to an embodiment of the present application;

FIG. 10 is a schematic plan view of an auxiliary recovery system in an operational state according to an embodiment of the present application;

FIG. 11 is an enlarged partial schematic view of the braided wires defining the development marks on the proximal edge of the tapered section of the self-expanding stent in an embodiment of the present application;

FIG. 12 is a schematic plan view of a self-expanding stent in accordance with an embodiment of the present application;

FIG. 13 is a cross-sectional view of the self-expanding stent of FIG. 12 at the A-A position;

FIG. 14 is a cross-sectional view of the self-expanding stent of FIG. 12 at the B-B position;

FIG. 15 is a schematic perspective view of an expandable segment of a self-expanding stent in a released state in accordance with an embodiment of the present application;

FIG. 16 is a schematic view of the structure of a self-expanding stent in accordance with an embodiment of the present application;

FIG. 17 is a schematic side view of a self-expanding stent in an embodiment of the present application;

FIGS. 18 a-18 d are schematic diagrams illustrating the crimping and overlapping process of a self-expanding stent in accordance with embodiments of the present application;

FIGS. 19-22 are schematic views of steps for removing a thrombus from a patient's blood vessel using a thrombus removal system provided in an embodiment of the present application;

fig. 23 is a schematic view of another structure of the thrombus removing device according to the embodiment of the present application, which includes only the first thrombus removing stand.

In the accompanying drawings:

10-a thrombus taking device; 11-push-pull guide wire; 12-connecting part; 13-a thrombus taking bracket; 13A-a bracket bar; 130A-a first bracket bar; 130B-a second bracket bar; 130C-the connection location of the first bracket bar and the second bracket bar; 130D-the connection site of the stent struts of the second mesh; 13B-straight bar; 13C-a tapered closed end; 131-a first thrombolytic stent; 131 a-first mesh; 131 b-a second mesh; 131 c-third mesh; 132-a second embolectomy stent; 14-a developing ring; 15-structural members; 16-open inlet; 17-overlapping portion; 18-free protruding portion; 30-an auxiliary recovery system; 31-a recovery conduit; 32-push-pull device; 321-push rod; 322-traction wire; 33-self-expanding stent; 33 a-distal opening; 33 b-notch; 331-a compression section; 332-conical section; 333-a support section; 334-developing the mark; 100-microcatheter; 101-thrombus; 102-vessel wall; 103-collateral blood vessel.

Detailed Description

Other advantages and effects of the present utility model will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present utility model with reference to specific examples. The utility model may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present utility model. It should be noted that, the illustrations provided in the present embodiment merely illustrate the basic concept of the present utility model by way of illustration, and only the components related to the present utility model are shown in the drawings and are not drawn according to the number, shape and size of the components in actual implementation, and the form, number and proportion of the components in actual implementation may be arbitrarily changed, and the layout of the components may be more complex.

The utility model will be further described in detail with reference to the accompanying drawings, in order to make the objects, advantages and features of the utility model more apparent. It should be noted that the drawings are in a very simplified form and are all to a non-precise scale, merely for convenience and clarity in aiding in the description of embodiments of the utility model. The same or similar reference numbers in the drawings refer to the same or similar parts. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second", etc. may explicitly or implicitly include one or more such feature. In the description of the present utility model, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

It should be noted that, the term "proximal" or "proximal" as used in the present document is generally the end closer to the operator when the medical device is implanted in a human or animal, and the term "distal" or "distal" is the end farther from the operator. "axial" generally refers to the longitudinal direction of the medical device when delivered, "radial" refers to the direction of the medical device perpendicular to its "axial direction," circumferential "refers to the direction about the central axis of the medical device itself.

The application aims at providing a thrombus removing system and an auxiliary recovery system to at least solve the problem that thrombus falling off in a withdrawing process of a thrombus taking bracket in the prior art easily enters side branch vessels and distal vessels.

The following description refers to the accompanying drawings. In the following description, while a microcatheter delivery embolic device is illustrated, those skilled in the art will recognize that in practice, interventional catheters other than microcatheters may be used to deliver embolic devices, such as guide catheters, etc., and those skilled in the art will be able to modify the following description to replace microcatheters with other interventional catheters for delivery.

Referring to fig. 1-23, an embodiment of the present application provides a thrombi removal system including a thrombi removal device 10 and an auxiliary recovery system 30. The thrombus taking device 10 comprises a push-pull guide wire 11 and a thrombus taking bracket 13 which are sequentially connected along the axial direction of the thrombus taking device 10. The push-pull guide wire 11 has a structure with certain toughness and bending property, and can push the thrombus taking device 10 to separate the thrombus taking device 10 from the micro-catheter 100 for release, and can pull the thrombus taking device 10 when withdrawing the thrombus taking device 10 to store the thrombus taking device 10 in the auxiliary recovery system 30. In practice, the auxiliary retrieval system 30 is able to move along the push-pull guidewire 11 to either approach or depart from the thrombolytic stent 13.

Referring to fig. 1 and 2, in one embodiment, the thrombolytic stent 13 includes a first thrombolytic stent 131 and a second thrombolytic stent 132. In another embodiment, as shown in fig. 23, the thrombolytic stent 13 comprises only a first thrombolytic stent 131. An exemplary description of a thrombolytic device 10 including a first thrombolytic stent 131 and a second thrombolytic stent 132 follows.

As shown in fig. 1 and 2, the thrombus-taking stand 13 includes a first thrombus-taking stand 131 and a second thrombus-taking stand 132, the first thrombus-taking stand 131 is a net-like structure formed by connecting a plurality of closed net holes, and the second thrombus-taking stand 132 is formed by a woven net. The proximal end of the first embolectomy 131 is connected to the distal end of the push-pull guidewire 11, and the distal end of the first embolectomy 131 is connected to the proximal end of the second embolectomy 132. Preferably, the distal end of the first embolectomy bracket 131 is flexibly connected to the proximal end of the second embolectomy bracket 132. Benefits of flexible connections include: the distal end of the first thrombus removing bracket 131 and the proximal end of the second thrombus removing bracket 132 can swing at a larger bending angle, so that the device can adapt to a larger bent blood vessel section and reduce the damage to the blood vessel wall during transportation in a tortuous blood vessel. It will be appreciated that the flexible connection may reduce the interaction between the first and second stent grafts 131, 132, reducing the damage to the vessel as the device 10 travels within the tortuous vessel. In addition, the secondary embolic stent 132 is effective to intercept escaping thrombus and thrombus fragments, preventing thrombus from drifting to the side branch vessel 103 and distal vessels.

In addition, while removing the thrombus, the thrombus removal device 10 may be delivered through the microcatheter 100 to deliver the thrombus removal device 10 to the thrombus removal site. As such, the thrombolytic device 10 has a compressed state in which it is received within the microcatheter 100 and a fully deployed state in which it is pushed out from the distal end of the microcatheter 100. When the thrombolytic device 10 is compressed within the microcatheter 100, the overall volume is reduced so that it may be placed within the microcatheter 100. Microcatheter 100 is adapted to deliver the embolic device 10 in a compressed state to a site of embolic delivery. When the thrombolytic device 10 is detached from the microcatheter 100, the restraint of the microcatheter 100 is lost and the device self-expands.

Referring to fig. 9-10, 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 recovery catheter 31 has an inner lumen extending therethrough in the axial direction. The push-pull device 32 is configured to be slidably disposed within the lumen of the retrieval catheter 31, and the push-pull device 32 is capable of pushing or pulling the self-expanding stent 33 in the axial direction of the retrieval catheter 31, thereby partially disengaging the self-expanding stent 33 from the retrieval catheter 31 or re-entering the deployed portion of the self-expanding stent 33 into the retrieval catheter 31.

Thus, the self-expanding stent 33 has a compressed state (see fig. 9) when delivered within the retrieval catheter 31 and a deployed state (see fig. 10) after partially detached from the retrieval catheter 31. In contrast, during the retraction of the thrombus captured by the thrombus collecting device 10, at least a part of the thrombus collecting stent 13 can be stored and recovered by the self-expanding stent 33 being separated from the part of the recovery catheter 31 which is deployed. That is, the self-expanding stent 33 has a lumen through which the thrombus-harvesting stent 13 can pass, and the thrombus-harvesting stent 13 after capturing a thrombus can be received in the lumen of the self-expanding stent 33 or further passed through the lumen of the self-expanding stent 33 into the retrieval catheter 31.

In actual use, the first thrombolytic stent 131 may be integrally stored in the self-expandable stent 33, further, the second thrombolytic stent 132 may close the distal opening 33a of the self-expandable stent 33 without entering the self-expandable stent 33, or the second thrombolytic stent 132 may close the distal opening 33a of the self-expandable stent 33 when partially entering the self-expandable stent 33, or the second thrombolytic stent 132 may completely enter the self-expandable stent 33 and close the self-expandable stent 33, or the first thrombolytic stent 131 and the second thrombolytic stent 132 may be completely stored in the self-expandable stent 33 and further pass through the self-expandable stent 33 to enter the recovery catheter 31. In this way, the second stent graft 132 can intercept thrombus distally during the process of capturing and withdrawing the thrombus by the first stent graft 131, and can also block the self-expanding stent 33 distally of the first stent graft 131 after the first stent graft 131 has entered the self-expanding stent 33, thereby further preventing the thrombus from escaping. Thus, the second embolectomy stent 132 may occlude the distal opening 33a of the self-expanding stent 33 distally outside of the self-expanding stent 33 without accessing the self-expanding stent 33, or the second embolectomy stent 132 may partially or fully access the self-expanding stent 33, thereby occluding the self-expanding stent 33.

Regardless of whether the embolic stent 13 is one or more, the auxiliary retrieval system 30 is configured to move along the push-pull guidewire 11 after removal of the microcatheter 100 delivering the embolic stent 13 and capture of a thrombus by the embolic stent 13, and positioned proximal to the embolic stent 13, and to control deployment of the self-expanding stent 33 partially out of the retrieval catheter 31, whereby the embolic stent 13 capturing a thrombus is moved proximally toward the auxiliary retrieval system 30 under the pull of the push-pull guidewire 11 and at least partially into the self-expanding stent 33 for retrieval via the distal opening 33a of the deployed self-expanding stent 33.

The method and steps of thrombus removal described in this embodiment will be further understood with reference to fig. 19 to 22.

As shown in fig. 19, the microcatheter 100 including 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 advanced distally such that the microcatheter 100 extends out of the distal end of the outer sheath and through the space between the thrombus 101 and the vessel wall 102, where the bulk thrombus 101 is substantially in place of the primary thrombus removal stent 131.

After the first stent 131 is positioned approximately at the thrombus 101 by the microcatheter 100, the microcatheter 100 is retracted proximally with the push-pull guidewire 11 intact as shown in fig. 20 until the microcatheter 100 is withdrawn from the body, during which the stent 10 gradually self-expands and comes into contact with the thrombus 101 during the retraction of the microcatheter 100, and the first stent 131 captures the thrombus 101.

After capturing the thrombus, as shown in fig. 21, the recovery catheter 31 including the self-expanding stent 33 is pushed to a position close to the first thrombus removing stent 131 along the push-pull guide wire 11 as much as possible, after the self-expanding stent 33 is pushed out towards the distal end direction of the recovery catheter 31 by the push-pull device 32 after the self-expanding stent 33 is released and attached to the vessel wall 102, the thrombus removing device 10 is pulled proximally by the push-pull guide wire 11 once a part of the structure of the self-expanding stent 33 is released and attached to the vessel wall 102, so that the thrombus removing device 10 moves proximally against the direction of the blood flow, at this time, part of thrombus fragments may fall off on the first thrombus removing stent 131, and the thrombus fragments move towards the second thrombus removing stent 132 along the direction of the blood flow, so that the second thrombus removing stent 132 can effectively intercept the fallen thrombus fragments because the second thrombus removing stent 132 is a woven mesh and attached to the vessel wall 102.

As shown in fig. 22, during retraction of the embolic device 10, the entire first embolic stent 131 may be moved into the lumen of the deployed portion of the self-expanding stent 33, at which time the second embolic stent 132 may be used to close the distal opening 33a of the self-expanding stent 33 without accessing the self-expanding stent 33. The self-expanding stent 33, the thrombectomy device 10, the retrieval catheter 31, etc. are then moved back in the proximal direction until fully retracted into the outer sheath.

In other cases, however, the thrombectomy stent 13 is moved in a proximal direction and passed through the self-expanding stent 33 directly into the retrieval catheter 31, e.g., the entirety of the thrombectomy device 10 capturing thrombus is withdrawn directly into the retrieval catheter 31 along the lumen of the self-expanding stent 33, at which point both the first and second thrombectomy stents 131, 132 are moved into the self-expanding stent 33, and the thrombectomy device 10 is pulled proximally until the thrombectomy device 10 is withdrawn into the retrieval catheter 31, and then the thrombectomy device 10 and the auxiliary retrieval system 30 together enter the outer sheath (also known as sheath) for withdrawal from the human body. In this case, the recovery duct 31 used for a slightly larger diameter is required, otherwise, there may be a case where the recovery duct 31 cannot be withdrawn. In this way, the thrombus-extracting stent 13 can be protected during the retraction of the thrombus-extracting device 10, and the captured thrombus is always kept in the self-expanding stent 33, so that the risk that the thrombus falls off into the side branch vessel 103 and the distal blood vessel due to tortuous vessels, plaque or calcification lesions possibly existing during the movement process is reduced.

Therefore, the thrombus taking support 13 of the embodiment can be retracted into the recovery catheter 31 from the occlusion position under the protection of the self-expanding support 33, so that thrombus falling in the retraction process can be effectively prevented from entering the side branch vessel 103 and the blood vessel at the far end, the thrombus taking efficiency and the thrombus taking success rate are improved, the risk of secondary stroke is reduced, and the operation safety is improved.

The self-expanding stent 33 is mainly composed of a woven mesh, but the present application does not exclude the self-expanding stent 33 being manufactured in a tube cutting manner. The self-expanding stent 33 may be a bare stent (i.e., not covered with a stent) or a stent covered with a stent. The self-expanding stent 33 is preferably woven from wire or polymer filaments having superelasticity and good shape memory. The self-expanding stent 33 prepared by the woven mesh can better protect the withdrawn thrombus taking stent 13 and better prevent thrombus from escaping in the withdrawing process.

Referring to fig. 12 to 14 and fig. 16 to 17, the self-expanding stent 33 is further defined with a notch 33b extending therethrough in the axial direction thereof, so that the self-expanding stent 33 is entirely formed of an open mesh. Further, the woven mesh from which the self-expanding stent 33 is made is capable of being transformed between a crimped state and a stretched state so that the self-expanding stent 33 can be shaped according to the size of the lumen in which it is positioned. In this way, the profile of the self-expanding stent 33 can accommodate lumens of different sizes, such as accommodating different sizes of retrieval catheters 31 and different sizes of blood vessels. Specifically, when the self-expanding stent 33 is placed in the lumen, the self-expanding stent 33 may be crimped accordingly to overlap partially or the crimped overlapping portion may be opened. Thus, the self-expanding stent 33 may vary as the diameter of the lumen being applied varies.

The crimping and shrinking process of the self-expanding stent 33 can be referred to in fig. 18a to 18d. It can be seen that the larger the diameter of the lumen used, the less or no overlap of the overlapping portions of the self-expanding stent 33, and if the diameter of the lumen is reduced, the self-expanding stent 33 can also be correspondingly crimped to create a partial overlap. So configured, the self-expanding stent 33 can be placed into a smaller diameter retrieval catheter 31 so that it can be used in smaller diameter vessels and delivered deeper into the vessel, and on the other hand, the self-expanding stent 33 will crimp and overlap when used in smaller lumen vessels and will open the "crimp and overlap" condition when used in larger lumen vessels so that it can be used in different diameter vessels, and on the other hand, the self-expanding stent 33 can also provide less radial support and less damage to the vessel inner wall when retracted. However, it should be understood that in other embodiments, the notch 33b may not be provided. After the notch 33b is eliminated, the self-expanding stent 33 has a circumferentially closed cylindrical structure and can still radially contract and expand.

Referring to fig. 10 and 12, in a specific embodiment, the self-expanding stent 33 comprises a compression section 331, a tapered section 332 and a cylindrical support section 333 connected in sequence along the axial direction thereof; the compression section 331 is always arranged in the recovery conduit 31 and is connected with the push-pull device 32; the tapered section 332 and the support section 333 can be deployed out of the recovery conduit 31. The tapered section 332 and the support section 333 constitute an expandable section that is superelastic in structure and has radial self-expanding properties. The outer diameter of the support section 333 is slightly larger than the vessel diameter applied so as to be able to closely fit the vessel inner wall. The tapered section 332 facilitates smooth sliding or stowing of the self-expanding stent 33 into the recovery catheter 31. A smooth transition connection between the tapered section 332 and the support section 333. The outer diameter of the support section 333 is equal to the outer diameter of the junction of the support section 333 and the tapered section 332, and the outer diameter of the junction of the support section 333 and the tapered section 332 is 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 junction of the tapered section 332 and the compression section 331, and the outer diameter of the junction of the tapered section 332 and the compression section 331 is the minimum outer diameter D1 of the tapered section 332. The compression section 331 is always kept free from the recovery conduit 31 under the constraint of the push-pull device 32.

As shown in fig. 11, in one embodiment, the proximal edge of the tapered section 332 of the self-expanding stent 33 is provided with a plurality of development marks 334, preferably a plurality of development marks 334, the plurality of development marks 334 being disposed circumferentially. In this way, during the operation, the operator (medical staff) can accurately position the self-expanding stent 33 during the pushing of the self-expanding stent 33, thereby preventing the self-expanding stent 33 from being completely pushed out of the recovery catheter 31, and increasing the safety and reliability of the operation. In a particular embodiment, the braided wire at the proximal edge of tapered segment 332 defines a plurality of development marks 334 thereon, and development marks 334 may be physically crimped onto the braided wire. Preferably, the plurality of developing marks 334 are uniformly distributed on the same circumference along the circumferential direction, the number of the developing marks 334 can be 2-8, and the developing marks 334 are made of platinum, gold, iridium and the like, which is not limited by the application.

Further, at least a portion of the outer surface of the self-expanding stent 33 is provided with a hydrophilic coating that may cover the entire outer surface of the self-expanding stent 33 or only the expandable section. The hydrophilic coating on the self-expanding stent 33 includes, but is not limited to, polyurethane, and other hydrophilic polymer materials may be used. And/or the distal inner wall of the retrieval catheter 31 is provided with a hydrophilic coating that reduces the coefficient of friction, facilitates easier pushing of the expandable segment out of the retrieval catheter 31, and also reduces trauma to the vessel by the self-expanding stent 33 during retraction. Hydrophilic coatings on the distal inner wall of the recovery catheter 31 include, but are not limited to, polyvinylpyrrolidone.

The present application is not limited to the structure of the push-pull device 32, and in practice, the push-pull device 32 may push or pull the self-expanding stent 33 in at least one manner. The following is an exemplary illustration.

As shown in fig. 9 and 10, in an exemplary embodiment, the push-pull device 32 includes a push rod 321 and a pull wire 322, wherein 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 extends through the push rod 321 to the proximal end of the recovery catheter 31, and the proximal end of the pull wire 322 may or may not be connected to the proximal end of the push rod 321, and forms a free end when disconnected. At this time, the distal end of the push rod 321 is used to abut against the proximal end of the self-expanding stent 33 to push the self-expanding stent 33 distally, and the traction wire 322 pulls the self-expanding stent 33 proximally. At least one traction wire 322 is provided, and in this embodiment, the traction wires 322 are multiple. In more detail, the proximal end of the compression section 331 is connected with a plurality of traction wires 322 by any one or more of welding, gluing, riveting, winding, etc.

In another example, the push-pull device 32 includes only a push rod 321, with the distal end of the push rod 321 being directly or indirectly connected to the proximal end of the self-expanding stent 33. At this time, the self-expanding stent 33 is pushed or pulled directly by the push rod 321. For ease of connection, the push rod 321 and the self-expanding stent 33 may be connected by a traction wire 322, i.e., the proximal end of the self-expanding stent 33 and the push rod 321 may be fixedly connected by the traction wire 322.

The preferred embodiment of the thrombolytic device 10 of the present embodiment is further described below.

Referring to fig. 1 and 2, further, the distal end of the first embolectomy 131 is connected to the proximal end of the second embolectomy 132 by a connector 12. The connecting portion 12 may connect the distal end of the first embolectomy 131 and the proximal end of the second embolectomy 132 in at least one manner, which is not limited in this regard. The connection 12 may be developable or undeveloped, preferably the connection 12 is developable. For example, in one illustrative example, the connecting portion 12 is formed of a developing wire that is helically wound in an axial direction around the distal end of the first embolectomy bracket 131 and the proximal end of the second embolectomy bracket 132. In another example, the connecting portion 12 is formed of a developable ring by which the distal end of the first embolectomy bracket 131 and the proximal end of the second embolectomy bracket 132 are crimped.

The manner of connection between the proximal end of the first embolectomy 131 and the distal end of the push-pull guidewire 11 is not limited, such as: winding, extrusion, medical gluing, laser welding, high polymer material fusion welding and other modes. In one embodiment, as shown in FIG. 1, a weld or glue bond is provided between the proximal end of the first embolectomy 131 and the distal end of the push-pull guidewire 11. In another embodiment, as shown in fig. 2, the proximal end of the first embolectomy 131 is coupled to the distal end of the push-pull guidewire 11 by a compression fit through the visualization ring 14.

As described above, the first embolectomy bracket 131 is a net tubular structure formed by connecting a plurality of closed meshes, and each closed mesh is formed by connecting a plurality of bracket rods 13A end to end in sequence, see fig. 3 in particular.

As shown in fig. 3 to 4, and fig. 7 and 8, in an exemplary embodiment, the distal end of the first thrombolytic bracket 131 includes a plurality of circumferentially arranged straight rods 13B, and the straight rods 13B are bundled to form a tapered closed end 13C at the distal end of the first thrombolytic bracket 131. This constriction at the distal end of the first embolectomy 131 facilitates connection with the proximal end of the second embolectomy 132.

As shown in fig. 1 and 2, in one example, the distal end of the secondary embolic stent 132 is constrained to be tapered. The distal ends of the secondary embolic brackets 132 are gathered and bound by the structural members 15 to prevent unraveling of the braided filaments at the distal ends. The structure 15 may be a sleeve, preferably a developing sleeve. The proximal end of the second embolectomy bracket 132 is coaxial with the distal end of the first embolectomy bracket 131.

The first embolectomy bracket 131 may be made of a metal alloy or a polymeric material, preferably nitinol, having superelasticity and good shape memory. The first embolectomy 131 may be formed by heat setting a cut tube, but is not limited thereto. The closed mesh in the first embolectomy 131 may be any shape, such as regular shapes like diamond, pentagon, etc., or irregular shapes, without limitation. The specific length and radial dimensions of the first stent 131 after deployment may be set depending on the diameter of the target vessel and the length of the thrombus. Optionally, the first thrombolytic stent 131 has an axial length of 13mm-50mm and a maximum radial width of 2.0mm-6.0mm when fully deployed. Alternatively, the width of the bracket bar 13A is 0.06mm-0.12mm; the first thrombus taking-out bracket 131 is designed according to the size, so that the supporting force and the radial size can be well combined.

Further, the closed mesh of the first embolectomy 131 is improved. Specifically, as shown in fig. 3, the closed cells in the first embolectomy 131 include a first cell 131a, a second cell 131b, and a third cell 131c, and the areas of the first cell 131a and the third cell 131c are smaller than the area of the second cell 131 b. The first mesh 131a is not overlapped with respect to the second mesh 131b and the third mesh 131c, and the third mesh 131c is disposed in the second mesh 131 b. At least two second mesh holes 131b cover at least one turn of the outer surface of the first thrombolytic stent 131. So, the first thrombus-taking bracket 131 adopts the structural design of multi-mesh mixing, and the structure ensures that the first thrombus-taking bracket 131 can effectively remove soft thrombus and hard thrombus, thereby further improving thrombus-taking efficiency and thrombus-taking success rate. Specifically, the area of the first mesh 131a is smaller, so that the thrombus can be conveniently embedded into soft thrombus, the second mesh 131b forms an open inlet 16 with a larger area, so that hard thrombus and soft thrombus can be embedded or embedded into the cavity of the first thrombus taking support 131 through the open inlets 16, and meanwhile, the third mesh 131c can form a space warping structure in the second mesh 131b, so that the third mesh 131c can inhibit the thrombus in the second mesh 131b from falling off or escaping, and the risk of falling off or escaping of thrombus can be further reduced.

The first thrombolytic stent 131 includes a proximal portion 1311, a middle portion 1312, and a distal portion 1313 connected in sequence. Further, a plurality of first mesh openings 131a are distributed over the proximal end portion 1311 and the distal end portion 1313, and the first mesh openings 131a may be uniformly or non-uniformly distributed, preferably uniformly distributed, over the first thrombolytic stent 131. The first mesh holes 131a are distributed along the axial direction and the circumferential direction of the first embolectomy 131. The first mesh 131a can provide a certain radial supporting force, so that the stent rod 13A is easier to embed into soft thrombus, and the first mesh 131a of the distal end portion 1313 of the first thrombus-taking stent 131 can also play a certain role in intercepting thrombus. The area (i.e., size) of the first mesh 131a on the distal end portion 1313 and the area of the first mesh 131a on the proximal end portion 1311 may be the same or different, and preferably the first mesh 131a on the distal end portion 1313 has a smaller area relative to the first mesh 131a on the proximal end portion 1311, so that the first mesh 131a on the distal end portion 1313 may provide better interception of thrombus within the lumen of the first thrombus-taking stent 131. Alternatively, the area of the first mesh 131a is 0.7mm ²-4.0mm².

The area of the second mesh 131b is much larger than that of the first mesh 131a. Here, "much larger" means that the area of the second mesh 131b is at least 2.5 times that of the first mesh 131a, and a specific multiple may be set by those skilled in the art according to actual needs, which is not limited herein. Preferably, the area of the second mesh 131b is 2.5 to 6 times that of the first mesh 131a. Further, a plurality of second mesh holes 131b are distributed on the middle portion 1312 at the position where thrombus is gathered.

Referring to fig. 5 and 7, a plurality of second mesh holes 131b may form a plurality of larger open inlets 16 at the outer surface of the first embolectomy 131. Because the open inlet 16 is relatively large, most of the hard and large soft thrombi can be embedded in the open inlet 16, and even pass completely through the open inlet 16 and into the lumen of the first embolectomy 131, reducing the contact surface of the thrombus with the vessel wall. And during retrieval, large and intact soft thrombi are embedded at the open inlet 16, small and broken soft and hard thrombi pass completely through the second mesh 131b into the lumen of the first embolectomy 131 and move relative to the first embolectomy 131 and thus free into the distal end of the first embolectomy 131. Since the mesh density of the first mesh 131a on the distal end portion 1313 is greater than that of the open inlet 16 (i.e., the second mesh 131 b), the contact area of the thrombus with the distal end of the first embolectomy 131 is increased, and the friction coefficient is also increased, so that the thrombus can be attached to the inner wall of the distal end of the first embolectomy 131 to achieve an interception effect.

The number of open inlets 16 is not less than 2, preferably 2 to 6. At least two open inlets 16 are arranged on the outer surface of the first thrombus removing bracket 131 at intervals, each open inlet 16 is formed by a second mesh 131b, and each open inlet 16 is communicated with the inner cavity of the first thrombus removing bracket 131.

Further, the plurality of second mesh holes 131b are distributed on different circumferences of the first embolectomy 131, and the second mesh holes 131b on different circumferences have overlapping portions in the circumferential direction and/or the axial direction of the first embolectomy 131. Thus, the existence of the thrombus removing dead zone can be reduced, the probability that the thrombus removing bracket 13 can be released once is increased, and the large thrombus and the hard thrombus can be successfully captured, so that the thrombus removing efficiency is improved, the operation time is shortened, and the pain of a patient is reduced. Specifically, the plurality of second mesh holes 131b have overlapping portions when seen from one end of the thrombus removing device 10 toward the other end, that is, when any one of the second mesh holes 131b is translated toward the other second mesh hole 131b in the axial direction of the thrombus removing device 10, the second mesh holes 131b always intersect at a certain position in the circumferential direction of the thrombus removing device 10, and there is always a case where one of the second mesh holes 131b partially covers the other second mesh hole 131 b. When any one of the second mesh holes 131b is translated toward the other second mesh hole 131b in the axial direction of the thrombectomy device 10, the second mesh holes 131b partially intersect at least at a certain position in the circumferential direction of the thrombectomy device 10, and the intersecting portions are overlapping portions.

For ease of understanding, please refer to the plan expanded view of the first stent 131 shown in fig. 3, taking two second meshes 131b defined on each circumference as an example, the overlapping portion 17 (the area defined by the broken line) of the second meshes 131b on the distal circumference and the second meshes 131b on the proximal circumference when seen from one end of the first stent 131 toward the other end, and the overlapping portion 17 exists between one second mesh 131b on one circumference and two adjacent second meshes 131b on the other circumference. That is, the second mesh holes 131b on different circumferences overlap in both the circumferential direction and the axial direction of the first embolectomy bracket 131.

Preferably, the open inlets 16 are evenly distributed in the circumferential and axial directions of the first thrombolytic bracket 131. The plurality of open inlets 16 can cover substantially the entire circumference of the outer wall of the first embolectomy 131 on the first embolectomy 131, and the open inlets 16 are continuously provided within a range corresponding to the length of the embolectomy. So, can reduce the thrombus blind area by a wide margin for when taking the thrombus, no matter the thrombus with the position of the outer wall contact of the first thrombus taking support 131 after the complete expansion, can always make the big thrombus imbed into the intracavity of first thrombus taking support 131 through a certain open entry 16 on the outer wall of first thrombus taking support 131, like this, can reduce translation operation and rotation operation, improve the thrombus efficiency. The circumferential length L of each second mesh 131b is about one-half of the circumference of the first embolectomy 131, and at least two second meshes 131b are capable of covering the outer surface of the first embolectomy 131 for one complete revolution in the circumferential direction.

Further, the third mesh 131c may be formed by: the second mesh 131b is provided therein with a free protruding portion 18 extending from the bracket bar 13A on one side into the second mesh 131b, the free protruding portion 18 having a closed mesh structure and forming a third mesh 131c. The free protruding portion 18 may be formed to extend distally from the support bar 13A at the proximal end of the second mesh 131b into the second mesh 131b, or the free protruding portion 18 may be formed to extend proximally from the support bar 13A at the distal end of the second mesh 131b into the second mesh 131 b. In this way, during deployment after the thrombus removal device 10 is released, thrombus can enter the cavity of the first thrombus removal holder 131 from the outer area of the third mesh 131c in the second mesh 131b, and when the thrombus removal device 10 is retracted, the free protruding portion 18 forming the third mesh 131c has the function of blocking the thrombus from being separated again from the second mesh 131b, which is beneficial for stabilizing the thrombus when the thrombus removal device 10 travels in a tortuous vessel and reducing the risk of thrombus separation.

The area of the third mesh 131c defined by the free protruding portion 18 is also much smaller than the area of the second mesh 131 b. It will be appreciated that the third mesh 131c has a support bar 13A independent of the second mesh 131B, the support bar 13A of the third mesh 131c including a first support bar 130A and a second support bar 130B, one end of each of the first support bar 130A and the second support bar 130B being connected to the support bar 13A of the second mesh 131B, the other ends of the first support bar 130A and the second support bar 130B being connected to each other to form a free protruding portion 18 extending toward the distal end or the proximal end, see fig. 5 in particular.

The length of the third mesh 131c should not affect the entry of thrombus, particularly large thrombi, into the lumen of the first embolectomy 131, alternatively the axial length of the third mesh 131c is 1/4-1/2 of the axial length of the second mesh 131 b.

Further, in order to accurately position the second mesh 131b, a developing object (not labeled) is disposed at the position of the first thrombus removing bracket 131 corresponding to the second mesh 131b, so that the contact condition of the first thrombus removing bracket 131 and the vascular thrombus can be clearly judged according to the development of the developing object under the X-ray, and the thrombus removing device 10 is moved or rotated, so that the second mesh 131b is accurately aligned with the massive thrombus, and the thrombus removing efficiency is improved.

In one embodiment, as shown in fig. 3 and 5, a groove is provided at the connection portion 130C of 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 fig. 6, a groove is provided at the connection portion 130D of the two bracket bars 13A adjacent to the second mesh 131b, and a developing substance is placed in the groove. The shape of the groove is not limited, and a circular groove is preferably selected for easy processing. In other embodiments, the support rod 13A of the second mesh 131b may be wound with a developing wire to form a developing object, such as one or more developing wires attached to the support rod 13A of the second mesh 131b in a spiral wound manner. The material of the developer is not particularly limited, and includes, but is not limited to, radiopaque metal developer such as platinum, gold, platinum iridium, tantalum, etc.

Thus, during the process of withdrawing the microcatheter 100, the thrombus removing device 10 is gradually self-expanding and brought into contact with the thrombus 101, at which time the position of the visualization object at the second mesh 131b can be observed by the imaging device, thereby observing whether the large thrombus 101 completely enters the lumen of the first thrombus removing stent 131, and if necessary, the thrombus 101 can be ensured to enter the open inlet 16 by the axial movement or the small-angle rotation of the thrombus removing device 10.

Further, the second embolectomy bracket 132 can be formed by weaving metal wires or polymer wires with super elasticity and good shape memory effect, and after weaving and shaping, the woven mesh with the required shape and size can be obtained by performing heat treatment and shaping through a mould. Preferably, the second embolectomy bracket 132 is formed by mixed braiding of a memory alloy wire and a radio-opaque noble metal wire, so that a doctor can conveniently judge the position of the second embolectomy bracket 132 in a blood vessel, and the efficiency and the accuracy of the operation are improved.

The second embolectomy bracket 132 is a mesh-disk structure, and the specific shape is not limited, and the shape with small contact area with the inner wall of the blood vessel should be selected as much as possible, such as: spherical, disk-like, basket-like, etc. In use, the second embolectomy stent 132 is deployed and then contacted with the inner wall of the blood vessel, preferably in line contact, with a small contact area and with little damage to the blood vessel. The second stent 132 has a denser closed mesh than the first stent 131 and is therefore available to intercept thrombus fragments that the first stent 131 falls during the thrombus removal process.

Preferably, the wire diameter of the braided wire in the second embolectomy 132 is smaller than the width of the stent rod 13A in the first embolectomy 131. Because the second embolectomy 132 mainly plays a role of interception, a large radial supporting force is not needed, and a fine woven wire is adopted as much as possible to form a woven dense net, but when the mesh is too dense, the second embolectomy 132 can be difficult to compress and collect into the microcatheter 100, thrombus fragments attached to the second embolectomy 132 are also easy to scrape off by the catheter, and for this problem, the wire diameter of the woven wire for preparing the second embolectomy 132 is preferably 0.02mm-0.12mm, and the area of the woven mesh is preferably 0.05mm ²-1mm².

In addition, the embodiment of the application also provides a method for removing thrombus by adopting the thrombus removing system, which comprises the following steps:

Delivering the thrombus taking support 13 through an interventional catheter, and conveying the thrombus taking support 13 to a thrombus taking position;

Withdrawing the interventional catheter to self-expand the thrombus taking support 13 and capture thrombus;

After capturing the thrombus, moving the recovery catheter 31 containing the self-expanding stent 33 along the push-pull guide wire 11 until the self-expanding stent 33 is positioned at the proximal side of the thrombus taking stent 13, and pushing out the self-expanding stent 33 towards the distal end direction of the recovery catheter 31 by the push-pull device 32 so as to enable the self-expanding stent 33 to be separated from the recovery catheter 31 to be partially unfolded;

Thereafter, pulling the thrombolytic stent 13 in a proximal direction by pushing and pulling the guidewire 11 until at least a portion of the thrombolytic stent 13 enters the self-expanding stent 33;

The embolic device 10 and the auxiliary retrieval system 30 may then be retracted together, such as to the outer sheath.

In summary, compared with the prior art, the auxiliary recovery system and the thrombus removal system provided by the application have at least the following advantages:

(1) In the auxiliary recovery system, the self-expanding stent can be mutually matched with the thrombus taking device, and the thrombus taking device can be at least partially pulled into the self-expanding stent in the process of withdrawing the thrombus captured by the thrombus taking device. So, the thrombus taking device can be retracted into the recovery catheter from the occlusion part under the protection of the self-expansion bracket, and thrombus falling off or falling off in the process of the self-expansion bracket can be effectively prevented from entering into the side branch blood vessel and the far-end blood vessel, so that the thrombus taking efficiency and the thrombus taking success rate are improved, the risk of secondary stroke is reduced, and the operation safety is increased.

Therefore, the thrombus taking device is retracted under the protection of the self-expanding stent, and can better avoid the thrombus from falling off into the side branch blood vessel and the blood vessel at the far end in the retraction process.

(2) The self-expansion bracket is provided with the notch extending along the axial direction of the self-expansion bracket, so that the external dimension of the self-expansion bracket can adapt to the diameter of a pipe cavity, such as a recovery catheter with different specifications and blood vessels with different sizes, the application range of the self-expansion bracket is enlarged, and the application of an auxiliary recovery system is more flexible and convenient. As such, upon placement of the self-expanding stent into the lumen, the self-expanding stent may be correspondingly crimped to partially overlap or the crimped overlap may be partially opened. This structure, on the one hand, the self-expanding stent can be put into a recovery catheter with smaller diameter so that it can be applied to a vessel with smaller diameter and sent to a deeper part of the vessel, on the other hand, the self-expanding stent can be curled and overlapped when being used for a vessel with smaller lumen and can be opened in a state of curling and overlapping when being used for a vessel with larger lumen so that it can be applied to vessels with different diameters, on the other hand, the self-expanding stent can also provide smaller radial supporting force and less damage to the inner wall of the vessel when being withdrawn.

(3) In the thrombus taking device, the first thrombus taking support adopts a multi-mesh mixed design, so that the first thrombus taking support can effectively remove soft thrombus and hard thrombus, and the thrombus taking efficiency and the thrombus taking success rate are further improved. Specifically, the first mesh openings have smaller area and are convenient to embed into soft thrombus, the second mesh openings form larger-area open inlets, so that hard thrombus and soft thrombus can be embedded or embedded into the cavity of the first thrombus taking support through the open inlets, and meanwhile, the third mesh openings form space warping structures in the second mesh openings, and therefore the third mesh openings inhibit thrombus in the second mesh openings from falling off or escaping.

(4) The second mesh in the first thrombus taking support has overlapping parts in the circumferential direction and the axial direction, so that the thrombus taking blind area can be reduced by the distribution mode, the probability that the thrombus taking support can successfully capture massive thrombus and hard thrombus by one-time release is increased, the thrombus taking efficiency is improved, the operation time is shortened, and the pain of patients is reduced.

(5) The first thrombus taking support is provided with a developing mark at the position corresponding to the second mesh, so that the developing of the developing mark under X-rays is facilitated, the position of the second mesh is accurately positioned, and therefore the large thrombus can be ensured to be embedded into or enter the cavity of the first thrombus taking support.

(6) The thrombus taking device can further comprise a second thrombus taking support, wherein the second thrombus taking support adopts a woven dense net, and can effectively intercept escaping thrombus and thrombus fragments when being matched with the first thrombus taking support.

Finally, it should be noted that as discussed herein, the "target" may be any form of obstruction, such as a red soft thrombus, a white hard thrombus, or other form of clot, and further, the "patient" or "individual" may be a human or any animal. It should be understood that the animal may be of any suitable type including, but not limited to, a mammal, a veterinary animal, a livestock animal or a companion animal, and the like. For example, the animal may be a laboratory animal (e.g., rat, dog, pig, monkey, etc.) specifically selected to have certain characteristics similar to humans.

The foregoing description is only illustrative of the preferred embodiments of the present utility model, and is not intended to limit the scope of the present utility model in any way, and any changes and modifications made by those skilled in the art in light of the foregoing disclosure will be deemed to fall within the scope and spirit of the present utility model.

Claims

1. A thrombus removal system, comprising:

The auxiliary recovery system comprises a recovery catheter, a push-pull device and a self-expansion bracket; the proximal end of the self-expanding stent is connected with 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-expanding bracket along the axial direction of the recovery catheter; the self-expanding stent has a compressed state when delivered within the retrieval catheter and a deployed state after partially disengaging the retrieval catheter;

The auxiliary recovery system is used for moving along the push-pull guide wire after the target object is captured by the thrombus taking support and is positioned at the near side of the thrombus taking support, so that the self-expansion support is partially separated from the recovery catheter to be unfolded;

2. The thrombectomy system of claim 1, wherein after the thrombectomy stent has been at least partially advanced into the self-expanding stent, the thrombectomy device and the auxiliary retrieval system are adapted to be moved together in a proximal direction to advance together into an outer sheath or the thrombectomy stent is moved in a proximal direction and advanced through the self-expanding stent into the retrieval catheter.

3. The thrombi removal system of claim 1 or 2, wherein said self-expanding stent is comprised of a woven mesh and defines a notch extending therethrough in an axial direction of said self-expanding stent.

4. A thrombus removal system as in claim 3 wherein the mesh is transformable between a crimped state and a deployed state to enable the self-expanding stent to adjust morphology depending on the size of the lumen in which it is located.

5. The thrombi removal system of claim 4, wherein said self-expanding stent comprises a compression section, a tapered section and a cylindrical support section connected in sequence along the axial direction of the self-expanding stent, said compression section being disposed within said recovery catheter and connected to said push-pull device, said tapered section and said support section being capable of being deployed out of said recovery catheter.

6. The thrombectomy system of claim 5, wherein the proximal edge of the tapered section is circumferentially provided with a plurality of radiopaque imaging markers.

7. The thrombectomy system of claim 1 or 2, wherein the push-pull device comprises a push rod having a distal end coupled to a proximal end of the self-expanding stent, or wherein the push-pull device comprises a push rod and a pull wire having a distal end coupled to a proximal end of the self-expanding stent, the proximal end of the pull wire passing through the push rod and extending to the proximal end of the retrieval catheter.

8. The thrombectomy system of claim 1 or 2, wherein at least a portion of an outer surface of the self-expanding stent is provided with a hydrophilic coating and/or wherein a distal inner wall of the recovery catheter is provided with a hydrophilic coating.

9. The thrombi removal system of claim 1 or 2, wherein said thrombi removal stent comprises a first thrombi removal stent, a proximal end of said first thrombi removal stent is connected with a distal end of said push-pull guidewire, said first thrombi removal stent is a mesh-like structure formed by a plurality of closed mesh connections, said closed mesh comprises a first mesh, a second mesh and a third mesh, both the area of said first mesh and the area of said third mesh are smaller than the area of said second mesh, said first mesh does not overlap with respect to said second mesh and said third mesh, said third mesh is disposed in said second mesh, and at least two of said second meshes cover at least one turn of the outer surface of said first thrombi removal stent.

10. The thrombi removal system of claim 9, wherein said second mesh has an area between 2.5 and 6 times the area of said first mesh.

11. The thrombectomy system of claim 9, wherein the first stent has visualization means disposed thereon at a location corresponding to the second mesh.

12. The thrombectomy system of claim 9, wherein the first thrombectomy stent comprises a proximal portion, a middle portion, and a distal portion connected in sequence, the first mesh being disposed on the proximal portion and the distal portion, the second mesh being disposed on the middle portion, the first mesh being smaller in area on the distal portion than the first mesh on the proximal portion.

13. The thrombectomy system of claim 9, wherein a plurality of the second mesh openings are distributed about different circumferences of the first thrombectomy stent, the second mesh openings having overlapping portions in the circumferential and/or axial directions of the first thrombectomy stent.

14. The thrombectomy system of claim 9, wherein the thrombectomy stent further comprises a second thrombectomy stent constructed of a braided mesh, the distal end of the first thrombectomy stent being flexibly connected to the proximal end of the second thrombectomy stent, the second thrombectomy stent being capable of occluding the self-expanding stent distally of the first thrombectomy stent after the first thrombectomy stent has entered the self-expanding stent.

15. The thrombectomy system of claim 14, wherein the second thrombectomy stent is configured to block a distal opening of the self-expanding stent distally externally of the self-expanding stent or at least partially into the self-expanding stent for occlusion.

16. An auxiliary recovery system is characterized by comprising a recovery catheter, a push-pull device and a self-expansion bracket; the proximal end of the self-expanding stent is connected with 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-expanding bracket along the axial direction of the recovery catheter; the self-expanding stent has a compressed state when delivered within the retrieval catheter and a deployed state after partially disengaging the retrieval catheter;

17. The auxiliary recovery system according to claim 16, wherein the self-expanding stent is formed of a woven mesh and defines a notch extending therethrough in an axial direction of the self-expanding stent.

18. The auxiliary retrieval system of claim 17, wherein the mesh is transformable between a crimped state and a deployed state such that the self-expanding stent is configured to adjust in shape according to the size of the lumen in which it is positioned.