Thrombectomy catheter

Abstract

This invention discloses a thrombectomy catheter, relating to the field of medical device technology, comprising: an inner tube and an outer tube. The inner tube includes an inner body segment and an inner extension segment, with the outer tube sleeved outside the inner body segment. The inner extension segment is integrally formed at the distal end of the inner body segment and extends beyond the outer tube. The inner extension segment is made of a flexible polymer material. The inner extension segment is configured to open and conform to the blood vessel wall under the action of the thrombectomy stent when pushed distally from within the catheter, and to close under the action of the thrombectomy stent and / or thrombus when withdrawn, thereby sealing the distal opening of the thrombectomy catheter. Therefore, the integral formation of the inner extension segment at the distal end of the inner body segment and extending beyond the outer tube reduces the risk of dislodgement or breakage, resulting in high safety and reliability. Furthermore, the inner extension segment provides thrombus escape prevention protection during both the pushing and withdrawing phases, significantly reducing the risk of thrombus escape.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a thrombectomy catheter. Background Technology

[0002] In related technologies, thrombectomy catheters are commonly used in endovascular thrombectomy. Currently, some thrombectomy catheters have a rigid, straight distal end, or consist of additional structures such as axial ribs, metal support frames, and independent flared tips connected to the distal end for dilation. These catheters cannot reduce the risk of thrombus escape during the thrombectomy procedure, and the additional structures not only increase manufacturing processes and costs but also pose risks of detachment and breakage. Therefore, there is room for improvement in current thrombectomy catheters. Summary of the Invention

[0003] The present invention aims to at least solve one of the technical problems existing in the prior art. Therefore, one object of the present invention is to provide a thrombectomy catheter that is highly safe and reliable, and capable of providing thrombus escape prevention protection in both the pushing and retraction phases, significantly reducing the risk of thrombus escape.

[0004] The thrombectomy catheter according to the present invention includes: an inner tube and an outer tube, wherein the inner tube includes an inner body section and an inner extension section, and the outer tube is sleeved on the outside of the inner body section; The inner extension section is integrally formed at the distal end of the inner body section and extends beyond the outer tube. The inner extension section is made of a flexible polymer material. The inner extension section is configured to open and conform to the blood vessel wall under the action of the thrombectomy stent when the thrombectomy stent is pushed distally from the thrombectomy catheter, and is configured to close under the action of the thrombectomy stent and / or thrombus when the thrombectomy stent is withdrawn, so as to block the distal opening of the thrombectomy catheter.

[0005] According to the thrombectomy catheter of the present invention, the inner extension section is integrally formed at the distal end of the inner body section and extends beyond the outer tube, which can reduce the risk of dislodgement or breakage of the inner extension section, and has high safety and reliability. Moreover, the inner extension section can realize thrombus escape prevention protection in both the pushing and retraction stages, significantly reducing the risk of thrombus escape.

[0006] In some examples of the present invention, the inner diameter of the inner layer extension gradually increases from one end of the inner layer extension closer to the inner layer body segment to the end farther away from the inner layer body segment.

[0007] In some examples of the present invention, the inner extension section includes a plurality of extension segments, which are arranged circumferentially and connected sequentially, and at least two of the extension segments have different lengths along the extension direction of the thrombectomy catheter.

[0008] In some examples of the present invention, at least a portion of the inner layer extension is formed with a continuous corrugated structure along the axial direction.

[0009] In some examples of the present invention, the inner extension segment includes: a first sub-segment, a second sub-segment, and a connecting sub-segment. The first sub-segment is integrally formed on the distal end of the inner body segment, the second sub-segment is sleeved on the first sub-segment, and the connecting sub-segment connects the distal end of the second sub-segment and the distal end of the first sub-segment and has an outer surface structured as an arc surface.

[0010] In some examples of the present invention, the wall thickness of the first sub-segment gradually decreases from one end of the first sub-segment near the inner body segment to the other end away from the inner body segment, and the wall thicknesses of the connecting sub-segment and the second sub-segment are not greater than the minimum wall thickness of the first sub-segment.

[0011] In some examples of the present invention, the wall thickness of the inner layer extension gradually decreases from one end of the inner layer extension closer to the inner layer body segment to the end farther away from the inner layer body segment.

[0012] In some examples of the present invention, the thrombectomy catheter further includes: a hydrophilic coating disposed on the surface of the inner extension; and / or, the thrombectomy catheter further includes: an antithrombotic coating disposed on the surface of the inner extension.

[0013] In some examples of the present invention, the flexible polymer material includes at least one of PTFE, FEP, PFA or PEBAX.

[0014] In some examples of the present invention, the outer tube includes: an outer body segment and a reinforcing layer, wherein the reinforcing layer is disposed between the outer body segment and the inner body segment.

[0015] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the thrombectomy catheter according to an embodiment of the present invention (when the thrombectomy stent is pushed). Figure 2 This is a cross-sectional view of the thrombectomy catheter according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the inner tube and the reinforcing layer according to an embodiment of the present invention; Figure 4This is a schematic diagram of the thrombectomy catheter according to an embodiment of the present invention (when the thrombectomy stent is retracted). Figure 5 This is a schematic diagram of the thrombectomy catheter according to an embodiment of the present invention (illustrating a corrugated structure). Figure 6 This is a schematic diagram of the thrombectomy catheter according to an embodiment of the present invention (showing the first segment, the second segment, and the connecting segment). Figure 7 yes Figure 6 Another perspective of the diagram; Figure 8 This is a cross-sectional view of the inner tube according to an embodiment of the present invention.

[0017] Figure label: 100 embolic retrieval catheters; Inner tube 10; Inner body section 11; Inner extension section 12; Corrugated structure 121; First sub-segment 122; Second sub-segment 123; Connecting sub-segment 124; Outer tube 20; outer body section 21; reinforcing layer 22. Detailed Implementation

[0018] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0019] The following is for reference. Figures 1-8 A thrombectomy catheter 100 according to an embodiment of the present invention is described.

[0020] like Figures 1-8 As shown, the thrombectomy catheter 100 according to an embodiment of the present invention includes: an inner tube 10 and an outer tube 20.

[0021] The inner tube 10 includes an inner body section 11 and an inner extension section 12, and the outer tube 20 is sleeved on the outside of the inner body section 11. The inner extension section 12 is integrally formed at the distal end of the inner body section 11 and extends beyond the outer tube 20.

[0022] In particular, along the extension direction of the thrombectomy catheter 100, a portion of the inner tube 10 extends beyond the outer tube 20 to form an inner extension section 12. The inner extension section 12 is integrally formed with the inner body section 11, which can significantly enhance the connection strength between the inner extension section 12 and the inner body section 11, greatly reducing the risk of the inner extension section 12 falling off or breaking, resulting in high safety and reliability.

[0023] The inner extension section 12 is made of flexible polymer material. The inner extension section 12 is configured to open and conform to the blood vessel wall under the action of the thrombectomy stent when it is pushed distally from inside the thrombectomy catheter 100, and is also configured to close under the action of the thrombectomy stent and / or thrombus when the thrombectomy stent is withdrawn, so as to block the distal opening of the thrombectomy catheter 100. As some embodiments of this application, in the process of producing the thrombectomy catheter 100, a co-extrusion or lamination process can be used to prepare a catheter including an inner tube 10 and an outer tube 20. Then, when cutting the catheter, the length of the inner tube 10 is made to exceed the length of the outer tube 20 to reserve the required inner extension section 12 (the length can be 3mm to 10mm). Then, the inner extension section 12 can be placed on a special mold, and mild heat and pressure (or only mechanical flaring combined with heat treatment) are applied to the inner extension section 12 to plastically deform it and form a preset flaring shape. After cooling, the flaring shape is fixed to complete the preparation of the thrombectomy catheter 100.

[0024] It is understood that this application creates an inner extension section 12 with entirely new functions simply by extending and shaping the inner tube 10 of the thrombectomy catheter 100. The proximal end of the inner extension section 12 is seamlessly connected to the inner body section 11 without any additional structures or extra connection interfaces, fundamentally eliminating the risk of additional structures falling off. It has high safety and reliability, and the manufacturing process is extremely simple with almost no increase in cost, which helps to simplify the manufacturing process and reduce costs.

[0025] The inner extension section 12 is made of flexible polymer material, which can reduce the risk of snagging and jamming during the pushing and retraction of the thrombectomy stent and significantly improve the smoothness of operation.

[0026] The inner extension 12 is configured to open and conform to the vessel wall under the action of the thrombectomy stent when it is pushed distally from inside the thrombectomy catheter 100, and is also configured to close under the action of the thrombectomy stent and / or thrombus when the thrombectomy stent is withdrawn, so as to block the distal opening of the thrombectomy catheter 100.

[0027] When the thrombectomy stent (not shown in the figure) is pushed distally from the thrombectomy catheter 100, the tip of the thrombectomy stent will contact and push against the inner extension section 12. Since the inner extension section 12 is made of flexible polymer material, the inner extension section 12 will be smoothly pushed open by the thrombectomy stent, opening from a closed or naturally flared state to form a smooth transition channel. This opened inner extension section 12 can play two roles in the blood vessel. First, it serves as a guide to ensure that the thrombectomy stent is pushed out completely without obstruction. Second, the inner extension section 12 can adhere to the blood vessel wall. Specifically, the soft, thin film-like edge of the inner extension section 12 can adhere to the blood vessel wall to form a temporary distal occlusion surface, effectively preventing tiny thrombus fragments that may detach during the operation from escaping to more distal parts of the blood vessel with the blood flow.

[0028] When the thrombectomy stent completes thrombus capture and retracts, the stent and the thrombus it carries move towards the inner extension segment 12. At this time, the stent and / or thrombus will contact the inner wall of the inner extension segment 12. With the application of the retraction force, the inner extension segment 12 will be pulled inward and proximally contracted (or folded). Due to the retraction action and the flexibility (or elasticity) of the inner extension segment 12, this contraction action will partially or completely close the opening at the distal end of the thrombectomy catheter 100 (i.e., block the distal opening of the thrombectomy catheter 100), acting as a temporary "one-way valve" or "gate". When the thrombectomy stent is fully inserted into the thrombectomy catheter 100, the contracted (or folded) inner extension segment 12 will adhere tightly to the inner wall of the thrombectomy stent and / or the thrombectomy catheter 100, effectively blocking the opening of the thrombectomy catheter 100 and effectively preventing the thrombus from escaping back into the blood vessel from the opening of the thrombectomy catheter 100 during the retraction process.

[0029] Moreover, it is understandable that throughout the entire process of pushing and retracting the thrombectomy catheter 100 distally, all movements of the inner extension segment 12 are passively triggered by the thrombectomy catheter 100, requiring no additional operation from the physician, effectively reducing the difficulty of the operation. In short, when the thrombectomy catheter 100 is pushed distally, the inner extension segment 12 opens and adheres to the vessel wall, forming a distal anti-escape barrier; when the thrombectomy catheter 100 is retracted, the inner extension segment 12 retracts inward to close the orifice of the thrombectomy catheter 100, forming a proximal anti-escape barrier. These two forms of the inner extension segment 12 passively and effectively block the risk of thrombus escape in both directions.

[0030] Optionally, the material of the inner extension segment 12 may include at least one of PTFE (Polytetrafluoroethylene), FEP (Fluorinated Ethylene Propylene), PFA (Polyfluoroalkoxy), or PEBAX (Polyether block Polyamide). This results in a low coefficient of friction for the inner extension segment 12, significantly reducing the frictional resistance between the thrombectomy stent and the inner wall of the inner extension segment 12, lowering the risk of stent snagging or jamming, and improving the smoothness of the surgical procedure. Furthermore, it ensures excellent biocompatibility of the inner extension segment 12, reducing irritation to vascular tissue, minimizing intraoperative thrombus adhesion and inflammatory response, and improving surgical safety. In addition, these materials have good thermoplasticity, facilitating the formation of the inner extension segment 12 into a predetermined flared shape through heat setting processes, resulting in simple processing and stable molding.

[0031] Therefore, the inner extension segment 12 is integrally formed at the distal end of the inner body segment 11 and extends beyond the outer tube 20, which can reduce the risk of the inner extension segment 12 falling off or breaking, and has high safety and reliability. Moreover, the inner extension segment 12 can achieve thrombus escape prevention protection in both the pushing and retraction stages, significantly reducing the risk of thrombus escape.

[0032] In some embodiments of the present invention, such as Figures 1-3 As shown, the inner diameter of the inner layer extension 12 gradually increases from the end closest to the inner layer body section 11 to the end furthest from the inner layer body section 11. In other words, the flared area of ​​the inner layer extension 12 gradually increases from the end closest to the inner layer body section 11 to the end furthest from the inner layer body section 11.

[0033] This design allows the inner extension section 12 to open under the action of the stent when it is pushed distally from the stent retrieval catheter 100, forming a smooth and gradually flared guide structure. This facilitates the smooth ejection of the stent, reduces the resistance to stent delivery, and prevents the stent from getting caught or stuck. Furthermore, it allows the inner extension section 12 to open outward and conform to the vessel wall more easily when the stent is pushed, forming a complete distal occlusion surface and improving the thrombus fragment escape prevention effect. Moreover, the smooth and gradually changing inner diameter without steps or sharp edges can reduce the shearing and scraping of the thrombus, reducing the risk of thrombus fragmentation and escape.

[0034] In some embodiments of the present invention, the inner extension segment 12 includes multiple extension segments arranged circumferentially and connected sequentially, with at least two extension segments having different lengths along the extension direction of the thrombectomy catheter 100. That is, the inner extension segment 12 is composed of multiple circumferentially arranged extension segments, each of which is connected to an adjacent extension segment circumferentially, and at least one extension segment has a length greater than one of the other extension segments. This allows the inner extension segment 12 to form an asymmetrical flared shape, better adapting to specific anatomical structures or operational requirements, improving the seal with the vessel wall, and the asymmetrical structure reduces the force required for deformation of the inner extension segment 12, making opening and closing smoother, further reducing irritation and damage to the vessel wall.

[0035] In some embodiments of the present invention, such as Figure 5 As shown, at least a portion of the inner extension 12 is along the axial direction (i.e. Figure 1 A continuous corrugated structure 121 is formed in the X direction (as shown). In other words, at least a portion of the inner extension 12 is constructed as a bellows-like structure, which allows the inner extension 12 to be axially (i.e., Figure 1 It is easier to stretch and compress in the X direction (as shown), which makes the inner extension section 12 more sensitive to the entry and exit of the thrombectomy stent and more flexible in deformation.

[0036] In some embodiments of the present invention, such as Figures 6-7 As shown, the inner extension segment 12 includes: a first sub-segment 122, a second sub-segment 123, and a connecting sub-segment 124. The first sub-segment 122 is integrally formed on the far end of the inner body segment 11. The second sub-segment 123 is sleeved on the first sub-segment 122. The connecting sub-segment 124 connects the far end of the second sub-segment 123 and the far end of the first sub-segment 122, and its outer surface is curved.

[0037] The second sub-segment 123 is fitted outside the first sub-segment 122, and the second sub-segment 123 and the first sub-segment 122 can be spaced apart, that is, there is a gap between the second sub-segment 123 and the first sub-segment 122.

[0038] Connecting segment 124 connects the distal end of the second segment 123 to the distal end of the first segment 122. In some embodiments of this application, one end of connecting segment 124 connects to the distal end of the second segment 123, and the other end connects to the distal end of the first segment 122. In some embodiments of this application, the first segment 122, the second segment 123, the connecting segment 124, and the inner body segment 11 are integrally formed. The second segment 123 and the connecting segment 124 can be formed by folding the inner extension segment 12 outwards and proximally. The outer surface of the connecting segment 124 can be constructed as a circular arc surface or an elliptical arc surface. This configuration ensures that the distal end of the inner extension segment 12 has no sharp edges, steps, or rigid cuts, forming a rounded, washer-like head end, which is less likely to scratch the blood vessel wall during pushing, significantly improving vascular safety.

[0039] In some embodiments of the present invention, the wall thickness of the first sub-segment 122 gradually decreases from the end of the first sub-segment 122 near the inner body segment 11 to the end away from the inner body segment 11. That is, the first sub-segment 122 gradually becomes thinner from the end of the first sub-segment 122 near the inner body segment 11 to the end away from the inner body segment 11. The wall thicknesses of the connecting sub-segment 124 and the second sub-segment 123 are not greater than the minimum wall thickness of the first sub-segment 122. For example, the wall thicknesses of the connecting sub-segment 124 and the second sub-segment 123 are both less than the minimum wall thickness of the first sub-segment 122, or the wall thicknesses of the connecting sub-segment 124 and the second sub-segment 123 are both equal to the minimum wall thickness of the first sub-segment 122.

[0040] This configuration allows the first segment 122 to have high proximal stiffness and good distal flexibility, ensuring structural support while allowing the inner extension segment 12 to gently conform to the vessel wall. The wall thickness of the connecting segment 124 and the second segment 123 is no greater than the minimum wall thickness of the first segment 122, which further enhances the distal deformation flexibility of the inner extension segment 12, making it easier for the inner extension segment 12 to open and close under the action of the thrombectomy stent, resulting in tight occlusion and sensitive response.

[0041] As some embodiments of this application, at least a portion of the first sub-segment 122 and at least a portion of the second sub-segment 123 are formed with a continuous corrugated structure 121 along the axial direction. In other words, at least a portion of the first sub-segment 122 and at least a portion of the second sub-segment 123 are constructed as a corrugated pipe-like structure. This arrangement makes it easier for the inner extension segment 12 to be stretched and compressed in the axial direction, and makes the inner extension segment 12 more sensitive to the entry and exit of the thrombectomy bracket and more flexible in deformation.

[0042] In some embodiments of the present invention, such as Figure 8 As shown, the wall thickness of the inner layer extension 12 gradually decreases from the end near the inner layer body segment 11 to the end away from the inner layer body segment 11. In other words, the inner layer extension 12 gradually becomes thinner from the end near the inner layer body segment 11 to the end away from the inner layer body segment 11.

[0043] This design allows the root of the inner extension segment 12 (i.e., the part where the inner extension segment 12 connects to the inner body segment 11) to be slightly thicker, acting as a hinge to facilitate the orderly folding of the inner extension segment 12. Furthermore, it allows the edge of the inner extension segment 12 (i.e., the distal end of the inner extension segment 12) to be thinner, making it easier for the inner extension segment 12 to open and conform to the vessel wall during stent delivery and easier to close and seal during retraction. This improves the reliability of preventing thrombus escape. This design also provides sufficient support at the proximal end of the inner extension segment 12 while allowing for greater flexibility at the distal end, balancing deformability reliability with vascular compliance.

[0044] In some embodiments of the present invention, the thrombectomy catheter 100 further includes: a hydrophilic coating disposed on the surface of the inner extension 12; and / or, the thrombectomy catheter 100 further includes: an antithrombotic coating disposed on the surface of the inner extension 12.

[0045] As some embodiments of this application, the thrombectomy catheter 100 further includes a hydrophilic coating disposed on the surface of the inner extension 12. As some embodiments of this application, the thrombectomy catheter 100 further includes an antithrombotic coating disposed on the surface of the inner extension 12. As some embodiments of this application, the thrombectomy catheter 100 further includes a hydrophilic coating and an antithrombotic coating, the hydrophilic coating and the antithrombotic coating being disposed on the surface of the inner extension 12. Wherein, when the thrombectomy catheter 100 includes a hydrophilic coating and an antithrombotic coating, the hydrophilic coating and the antithrombotic coating can be mixed and disposed on the surface of the inner extension 12, or the hydrophilic coating and the antithrombotic coating can be disposed in layers, for example, the hydrophilic coating is disposed outside the antithrombotic coating, or the antithrombotic coating is disposed outside the hydrophilic coating.

[0046] The hydrophilic coating can be selected from at least one of polyvinylpyrrolidone, polyethylene glycol, polyacrylic acid, polyurethane-based hydrophilic coating, or silicone-based hydrophilic coating. It is understood that the surface friction coefficient is significantly reduced after the hydrophilic coating comes into contact with blood. By applying a hydrophilic coating to the surface of the inner extension 12, the thrombectomy stent can be pushed and retracted more smoothly, making it less prone to snagging or jamming, and reducing friction and irritation to the blood vessel wall, thus improving surgical safety and biocompatibility.

[0047] The antithrombotic coating can be selected from at least one of heparin coating, phosphorylcholine coating, aspirin-loaded coating, nitric oxide-releasing coating, or polyisoprene-based antithrombotic coating. The antithrombotic coating can effectively inhibit the adhesion and aggregation of thrombi at the distal end of the thrombectomy catheter 100, reducing intraoperative secondary thrombus formation and lowering the risk of re-embolism.

[0048] By combining the antithrombotic coating with the hydrophilic coating, the thrombectomy stent can be pushed and withdrawn more smoothly, and the adhesion and aggregation of thrombi at the distal end of the thrombectomy catheter can be inhibited, significantly improving the safety and success rate of the procedure.

[0049] In some embodiments of the present invention, the flexible polymer material includes at least one of PTFE (Polytetrafluoroethylene), FEP (Fluorinated Ethylene Propylene), PFA (Polyfluoroalkoxy), or PEBAX (Polyether block Polyamide). This results in a low coefficient of friction for the inner extension 12, significantly reducing frictional resistance between the thrombectomy stent and the inner wall of the inner extension 12, lowering the risk of stent snagging or jamming, and improving surgical smoothness. Furthermore, it ensures excellent biocompatibility of the inner extension 12, reducing irritation to vascular tissue, minimizing intraoperative thrombus adhesion and inflammatory response, and improving surgical safety. In addition, these materials have good thermoplasticity, facilitating the formation of the inner extension 12 into a predetermined flared shape through heat setting processes, resulting in simple processing and stable molding.

[0050] In some embodiments of the present invention, such as Figures 1-8 As shown, the outer tube 20 includes an outer body section 21 and a reinforcing layer 22, with the reinforcing layer 22 disposed between the outer body section 21 and the inner body section 11.

[0051] For example, the outer body segment 21, the reinforcing layer 22, and the inner body segment 11 are sequentially nested and connected from the outside to the inside. The reinforcing layer 22 can be constructed as at least one of a braided mesh structure, a spiral winding structure, or a laser-engraved tube structure. The material of the reinforcing layer 22 can be at least one of 304 stainless steel, nickel-titanium alloy, or polymer fiber. The reinforcing layer 22 provides support and resistance to negative pressure collapse, improving the success rate of thrombectomy. The reinforcement layer 22 effectively prevents the thrombectomy catheter 100 from kinking or twisting within the blood vessel, ensuring smooth passage of the thrombectomy stent.

[0052] The outer body segment 21 can be made of polymeric materials with good toughness and biocompatibility, such as PE (Polyethylene), PEBAX (Polyether block Polyamide), PA (Polyamide), and PU (Polyurethane). The outer body segment 21 can wrap around and protect the inner reinforcing layer 22 and the inner body segment 11, making the overall structure of the thrombectomy catheter 100 intact and the surface smooth, reducing friction and damage to the blood vessel during the advancement process. Moreover, the use of a polymeric material with good toughness and biocompatibility in the outer body segment 21 can adjust the overall hardness and flexibility of the thrombectomy catheter 100, and work with the reinforcing layer 22 to achieve good support and passage.

[0053] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0054] In the description of this invention, "first feature" and "second feature" may include one or more of the features.

[0055] In the description of this invention, "a plurality of" means two or more.

[0056] In the description of this invention, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or it may include the first and second features not being in direct contact but being in contact through another feature between them.

[0057] In the description of this invention, the terms "above," "over," and "on top" for the first feature and the second feature include the first feature being directly above or diagonally above the second feature, or simply indicating that the first feature is at a higher horizontal level than the second feature.

[0058] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0059] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A thrombectomy catheter, characterized in that, include: The inner tube and the outer tube, wherein the inner tube includes an inner body section and an inner extension section, and the outer tube is sleeved on the outside of the inner body section; The inner extension section is integrally formed at the distal end of the inner body section and extends beyond the outer tube. The inner extension section is made of a flexible polymer material. The inner extension section is configured to open and conform to the blood vessel wall under the action of the thrombectomy stent when the thrombectomy stent is pushed distally from the thrombectomy catheter, and is configured to close under the action of the thrombectomy stent and / or thrombus when the thrombectomy stent is withdrawn, so as to block the distal opening of the thrombectomy catheter.

2. The thrombectomy catheter according to claim 1, characterized in that, The inner diameter of the inner layer extension gradually increases from the end closest to the inner layer body section to the end furthest from the inner layer body section.

3. The thrombectomy catheter according to claim 2, characterized in that, The inner extension section includes multiple extension segments, which are arranged circumferentially and connected sequentially, and at least two of the extension segments have different lengths along the extension direction of the thrombectomy catheter.

4. The thrombectomy catheter according to claim 1, characterized in that, At least a portion of the inner layer extension section forms a continuous corrugated structure along the axial direction.

5. The thrombectomy catheter according to claim 1, characterized in that, The inner extension segment includes: a first sub-segment, a second sub-segment, and a connecting sub-segment. The first sub-segment is integrally formed on the far end of the inner body segment. The second sub-segment is sleeved on the first sub-segment. The connecting sub-segment connects the far end of the second sub-segment and the far end of the first sub-segment, and its outer surface is curved.

6. The thrombectomy catheter according to claim 5, characterized in that, From the end of the first sub-segment closest to the inner body segment to the end furthest from the inner body segment, the wall thickness of the first sub-segment gradually decreases, and the wall thickness of the connecting sub-segment and the second sub-segment is not greater than the minimum wall thickness of the first sub-segment.

7. The thrombectomy catheter according to any one of claims 1-4, characterized in that, The wall thickness of the inner layer extension gradually decreases from one end near the inner layer body section to the other end away from the inner layer body section.

8. The thrombectomy catheter according to any one of claims 1-5, characterized in that, Also includes: A hydrophilic coating is provided on the surface of the inner layer extension; And / or, further comprising: an antithrombotic coating, said antithrombotic coating being disposed on the surface of the inner layer extension.

9. The thrombectomy catheter according to any one of claims 1-5, characterized in that, The flexible polymer material includes at least one of PTFE, FEP, PFA, or PEBAX.

10. The thrombectomy catheter according to any one of claims 1-5, characterized in that, The outer tube includes an outer body section and a reinforcing layer, wherein the reinforcing layer is disposed between the outer body section and the inner body section.

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