A microcatheter and a method of manufacturing the same

Abstract

This application provides a microcatheter and its preparation method, relating to the field of medical device technology. The microcatheter includes a tube body, a first radiopaque ring, a second radiopaque ring, and a reinforcing tube. The tube body includes an inner layer assembly, a middle layer assembly, and an outer layer assembly arranged sequentially from the inside out. The middle layer assembly at the distal end of the tube body includes a coiled wire. Both the first and second radiopaque rings are disposed between the middle and outer layer assemblies at the distal end of the tube body, with the first radiopaque ring being closer to the distal end of the tube body than the second radiopaque ring. The reinforcing tube is disposed between the middle layer assembly and the second radiopaque ring. The distal end of the tube body is used to extend into the human body, and the proximal end is used to connect a therapeutic device or deliver diagnostic agents to the distal end of the tube body. By placing a reinforcing tube between the middle layer assembly and the second radiopaque ring, the microcatheter of this application can increase the tensile strength at the second radiopaque ring, thereby reducing the risk of the tube body breaking at the second radiopaque ring during use.

Description

Technical Field

[0001] This application relates to the field of medical device technology, and more specifically, to a microcatheter and its preparation method. Background Technology

[0002] Neurointerventional microcatheters are novel medical devices used for cardiovascular and cerebrovascular diseases that are otherwise inoperable due to high risks. It is explained that because the brain and spinal cord are the body's central nervous system, deep or complex lesions such as intracranial aneurysms, carotid sinus fistulas, and vascular malformations are often inoperable, or the surgery is difficult and carries serious sequelae. In recent years, the continuous development of neurointerventional radiology and the emergence of high-performance polymer catheters have ushered in a new era of endovascular treatment for intracranial aneurysms. Currently, in clinical practice, neurointerventional microcatheters are mainly used to infuse diagnostic agents—such as contrast agents—and therapeutic devices—such as coils—into neurovascular vessels.

[0003] The microcatheter mainly consists of a catheter seat, a tube body, and a radiopaque ring. The distal end of the tube body is provided with a first radiopaque ring and a second radiopaque ring. The proximal end of the tube body is fixedly connected to the catheter seat. The tube body often breaks at the second radiopaque ring during use. Summary of the Invention

[0004] This application provides a microcatheter and its preparation method, which can increase the tensile strength at the second imaging ring, thereby avoiding or improving the problem of tube body breakage at the second imaging ring.

[0005] In a first aspect, embodiments of this application provide a microcatheter, comprising: a tube body, a first radiopaque ring, a second radiopaque ring, and a reinforcing tube. The tube body includes an inner layer assembly, a middle layer assembly, and an outer layer assembly arranged sequentially from the inside to the outside. The tube body has a proximal end and a distal end. The middle layer assembly at the distal end of the tube body includes a coiled wire. The first radiopaque ring and the second radiopaque ring are both disposed between the middle layer assembly and the outer layer assembly at the distal end of the tube body, and the first radiopaque ring is closer to the distal end of the tube body than the second radiopaque ring. The reinforcing tube is disposed between the middle layer assembly and the second radiopaque ring.

[0006] In the above implementation process, the distal end of the microcatheter body is used to extend into the human body, and the proximal end of the body is used to connect a therapeutic device or deliver diagnostic agents to the distal end of the body. The microcatheter of this application can improve the tensile strength at the second imaging ring of the microcatheter by setting a reinforcing tube between the intermediate layer component and the second imaging ring, thereby reducing the risk of the microcatheter body breaking at the second imaging ring during use.

[0007] In one possible implementation, the reinforcing tube is connected to the outer component, and the second imaging ring is embedded between the reinforcing tube and the outer component.

[0008] In the above implementation process, the microcatheter of this application can further improve the tensile strength at the second imaging ring of the microcatheter by embedding the second imaging ring between the reinforcing tube and the outer layer component, thereby reducing the risk of the tube body breaking at the second imaging ring during use.

[0009] In one possible implementation, the distance between the two ends of the reinforcing tube and the corresponding ends of the second imaging ring is 0 to 1 cm.

[0010] In the above implementation process, by making the distances at both ends of the reinforcing tube beyond the corresponding ends of the second imaging ring within the above range, the tensile force at the second imaging ring of the microcatheter can be further increased, thereby reducing the risk of the microcatheter body breaking at the second imaging ring during use.

[0011] In one possible implementation, the reinforcing tube is made of at least one of polyamide, nylon, and polyurethane.

[0012] In the above implementation process, the microcatheter of this application is made of the above-mentioned material to make the reinforcing tube, which is beneficial to improve the fusion effect between the reinforcing tube and the outer component, and enables the reinforcing tube and the outer component to be connected by fusion.

[0013] In one possible implementation, the reinforcing tube is made of the same material as the outer component.

[0014] In the above implementation process, the microcatheter of this application improves the fusion effect between the reinforcing tube and the outer component by making the material of the reinforcing tube the same as that of the outer component, and enables the reinforcing tube and the outer component to be connected by fusion.

[0015] In one possible implementation, the inner layer component is made of polytetrafluoroethylene (PTFE).

[0016] In one possible implementation, the intermediate layer assembly at the proximal end of the tube body includes braided filaments;

[0017] Optionally, the intermediate layer component may be made of metal.

[0018] Alternatively, the metallic material includes at least one of stainless steel, nickel-titanium and tungsten.

[0019] In one possible implementation, the hardness of the outer component at the distal end of the tube is less than the hardness of the outer component at the proximal end of the tube.

[0020] In one possible implementation, the tube body further includes a hydrophilic coating disposed on the outer surface of the outer component;

[0021] Optionally, the hydrophilic coating material includes polyvinylpyrrolidone and / or polyacrylamide.

[0022] Secondly, this application provides a method for preparing a microcatheter, comprising: winding a spring wire around the outer surface of an inner layer component to form an intermediate layer component; then fitting a heat-shrinkable tube over the intermediate layer component for rheoforming; removing the heat-shrinkable tube; welding a reinforcing tube to the second developing ring position of the intermediate layer component by heat fusion; then fixing the first developing ring and the second developing ring to the distal end of the outer surface of the intermediate layer component by pressing, so that the reinforcing tube is positioned between the intermediate layer component and the second developing ring; and finally fitting an outer layer component over the inner layer component.

[0023] In the above-mentioned process, the preparation method of this application is simple, the microcatheter structure is stable, and the tensile strength at the second imaging ring is improved. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of the microcatheter according to an embodiment of this application;

[0026] Figure 2 This is a perspective view of the tube body according to an embodiment of this application;

[0027] Figure 3 This is a schematic diagram of the three-layer structure of the tube body according to an embodiment of this application;

[0028] Figure 4 for Figure 1 Or a radial section view at position AA of 2;

[0029] Figure 5 for Figure 1 Or a radial section view of position BB at point 2.

[0030] Icons: 10-Microcatheter; 100-Cauliform body; 101-Proximal end; 102-Distal end; 110-Inner layer assembly; 111-Inner lumen; 120-Intermediate layer assembly; 121-Spring wire; 122-Braided wire; 130-Outer layer assembly; 140-Hydrophilic coating; 200-Catheter seat; 201-Main lumen; 300-Protective sheath; 310-First protective sheath; 320-Second protective sheath; 400-First radiopaque ring; 500-Second radiopaque ring; 600-Reinforcing tube. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0032] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0033] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0034] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. These terms are used only for the convenience of describing this application and for 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 application. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0035] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0036] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0037] Currently, the body of a microcatheter consists of an inner layer, a middle layer, and an outer layer arranged sequentially from the inside out. The middle layer at the distal end of the body has a spring-like structure, which allows the distal end of the body to have better compliance.

[0038] However, this application found that the poor stability of the coiled spring structure leads to insufficient tension at the second imaging ring of the tube, which in turn causes the tube to break at the second imaging ring during the use of the microcatheter.

[0039] Based on the above issues, please refer to Figure 1 This application provides a microcatheter 10, which includes: a tube body 100, a catheter seat 200, a protective sleeve 300, a first imaging ring 400, a second imaging ring 500, and a reinforcing tube 600.

[0040] The tube body 100 is connected to the conduit seat 200 via a protective sleeve 300, which is used to ensure a stable connection between the conduit seat 200 and the tube body 100.

[0041] Optionally, one end of the protective sleeve 300 is fitted onto the pipe body 100, and the other end of the protective sleeve 300 is connected to the conduit seat 200 by a snap-fit.

[0042] Optionally, the protective sleeve 300 includes a first protective sleeve 310 and a second protective sleeve 320, one end of the first protective sleeve 310 and one end of the second protective sleeve 320 are connected, the other end of the first protective sleeve 310 is connected to the end of the tube body 100, and the other end of the second protective sleeve 320 is connected to the conduit seat 200.

[0043] Optionally, the catheter hub 200 has a main lumen 201, which can be used to accommodate microwires, injectable drugs, and therapeutic devices such as coils.

[0044] Optionally, the conduit seat 200 may be made of nylon and / or polycarbonate.

[0045] Please see Figures 1-4 The tube body 100 has a proximal end 101 near the conduit seat 200 and a distal end 102 away from the conduit seat 200. The tube body 100 includes an inner layer assembly 110, an intermediate layer assembly 120 and an outer layer assembly 130 arranged sequentially from the inside to the outside. The inner layer assembly 110, the intermediate layer assembly 120 and the outer layer assembly 130 can be fused together by rheoforming.

[0046] Please see Figures 2-5 The inner layer component 110 is a tubular structure with an inner cavity 111 connected to the main cavity 201 of the catheter seat 200. The inner cavity 111 of the inner layer component 110 is formed as a delivery channel for delivering injectable drugs or instruments.

[0047] Optionally, the inner component 110 may be made of polytetrafluoroethylene.

[0048] The intermediate layer assembly 120 includes a coiled wire 121 and a braided wire 122, which are fixed to the outer surface of the inner layer assembly 110.

[0049] The intermediate layer assembly 120 near the proximal end 101 of the tube body 100 includes braided wire 122, and the intermediate layer assembly 120 near the distal end 102 of the tube body 100 includes coiled wire 121.

[0050] The braided wire 122 is formed by braiding metal wires, and the coiled wire 121 is formed by winding metal wires. The connection between the braided wire 122 and the coiled wire 121 is a transition section, and in the transition section, the braided wire 122 and the coiled wire 121 overlap. The intermediate layer assembly 120 includes the overlapping braided wire 122 and the coiled wire 121.

[0051] Optionally, the materials of the coiled wire 121 and the braided wire 122 may include metal materials.

[0052] Optionally, the material of the coiled wire 121 and the braided wire 122 includes at least one of stainless steel, nickel-titanium and tungsten.

[0053] It should be noted that the materials of the coiled wire 121 and the braided wire 122 can be the same or different. For example, the materials of the coiled wire 121 and the braided wire 122 can both be stainless steel, nickel-titanium alloy or tungsten metal; or the coiled wire 121 can be stainless steel and the braided wire 122 can be nickel-titanium alloy; or the coiled wire 121 can be tungsten metal and the braided wire 122 can be nickel-titanium alloy; or the coiled wire 121 can be nickel-titanium alloy and the braided wire 122 can be stainless steel.

[0054] The outer component 130 is a tubular structure. The outer component 130 is sleeved outside the inner component 110 and the outer component 130 and the inner component 110 are coaxially connected. The inner surface of the outer component 130 abuts against the intermediate component 120. A spiral channel for delivering contrast agent is formed between the inner component 110 and the outer component 130.

[0055] The hardness of the outer component 130 at the distal end 102 of the tube body 100 is less than the hardness of the outer component 130 at the proximal end 101 of the tube body 100.

[0056] Optionally, the outer layer assembly 130 of the tube body 100 includes a first segment, a second segment, a third segment, and a fourth segment extending sequentially from the proximal end 101 to the distal end 102, and the hardness of the first segment is greater than that of the second segment, which is greater than that of the third segment, which is greater than that of the fourth segment. The first segment, the second segment, the third segment, and the fourth segment of the outer layer assembly 130 of the tube body 100 can be welded together by hot melting, laser welding, or a combination thereof to form the entire outer layer assembly 130.

[0057] Optionally, the hardness of the first segment of the outer component 130 of the tube body 100 is 72D, the hardness of the second segment is 55D, the hardness of the third segment is 40D, and the hardness of the fourth segment is 35D.

[0058] The outer component 130 is made of at least one of polyamide, nylon and polyurethane.

[0059] The outer surface of the outer component 130 is provided with a hydrophilic coating 140, which can be formed on the outer surface of the outer component 130 by means of photocuring, thermocuring or other methods.

[0060] Optionally, the hydrophilic coating 140 may be made of polyvinylpyrrolidone and / or polyacrylamide.

[0061] The first developing ring 400 and the second developing ring 500 are both disposed between the intermediate layer assembly 120 and the outer layer assembly 130 at the distal end 102 of the tube body 100, and the first developing ring 400 is closer to the distal end 102 of the tube body 100 than the second developing ring 500. The reinforcing tube 600 is disposed between the intermediate layer assembly 120 and the second developing ring 500.

[0062] Optionally, both the first developing ring 400 and the second developing ring 500 are made of platinum-iridium alloy.

[0063] Optionally, the outer component 130 abutted by the second developing ring 500 has a hardness of 35D.

[0064] The reinforcing tube 600 can be welded between the intermediate layer assembly 120 and the second developing ring 500 by heat fusion. During this welding process, the reinforcing tube 600 is fused with the outer layer assembly 130 by rheological means. This not only allows the tube body 100 to be interconnected and play a flow role during rheological processes, but also allows the second developing ring 500 to be embedded between the reinforcing tube 600 and the outer layer assembly 130. This can further increase the tensile strength at the second developing ring 500 of the microcatheter 10, thereby reducing the risk of the tube body 100 breaking at the second developing ring 500 during use.

[0065] Optionally, the two ends of the reinforcing tube 600 are aligned with or extend beyond the corresponding ends of the second developing ring 500.

[0066] The correspondence between the two ends of the reinforcing tube 600 and the corresponding ends of the second developing ring 500 is as follows:

[0067] The end of the reinforcing tube 600 that is far from the proximal end 101 of the tube body 100 (i.e., near the distal end 102 of the tube body 100) corresponds to the end of the second developing ring 500 that is far from the proximal end 101 of the tube body 100 (i.e., near the distal end 102 of the tube body 100), and the end of the reinforcing tube 600 that is near the proximal end 101 of the tube body 100 (i.e., far from the distal end 102 of the tube body 100) corresponds to the end of the second developing ring 500 that is near the proximal end 101 of the tube body 100 (i.e., far from the distal end 102 of the tube body 100).

[0068] Optionally, the distance between the two ends of the reinforcing tube 600 and the corresponding ends of the second developing ring 500 is 0-1 cm.

[0069] As an example, the distances at which the two ends of the reinforcing tube 600 extend beyond the corresponding ends of the second developing ring 500 can be 0, 0.1cm, 0.2cm, 0.3cm, 0.4cm, 0.5cm, 0.6cm, 0.7cm, 0.8cm, 0.9cm, or 1cm.

[0070] It should be noted that when the distance between the two ends of the reinforcing tube 600 and the corresponding ends of the second developing ring 500 is 0, the two ends of the reinforcing tube 600 are aligned with the corresponding ends of the second developing ring 500.

[0071] By ensuring that the distances at both ends of the reinforcing tube 600 beyond the corresponding ends of the second imaging ring 500 are within the aforementioned range, the tensile force at the second imaging ring 500 of the microcatheter 10 can be further increased, thereby reducing the risk of the tube body 100 breaking at the second imaging ring 500 during use.

[0072] Optionally, the reinforcing tube 600 may be made of at least one of polyamide, nylon, and polyurethane.

[0073] The microcatheter 10 of this application uses the above-mentioned material to make the reinforcing tube 600, which is beneficial to improving the fusion effect between the reinforcing tube 600 and the outer component 130, and enables the reinforcing tube 600 and the outer component 130 to be connected by fusion.

[0074] Optionally, the reinforcing tube 600 is made of the same material as the outer component 130.

[0075] For example, when the outer component 130 is made of polyamide, the reinforcing tube 600 is also made of polyamide; when the outer component 130 is made of nylon, the reinforcing tube 600 is also made of nylon; when the outer component 130 is made of polyurethane, the reinforcing tube 600 is also made of polyurethane; when the outer component 130 is made of a mixture of polyurethane and nylon, the reinforcing tube 600 is also made of a mixture of polyurethane and nylon; when the outer component 130 is made of a mixture of polyamide and nylon, the reinforcing tube 600 is also made of a mixture of polyamide and nylon.

[0076] The microcatheter 10 of this application improves the fusion effect between the reinforcing tube 600 and the outer component 130 by making the reinforcing tube 600 and the outer component 130 the same material, and enables the reinforcing tube 600 and the outer component 130 to be connected by fusion.

[0077] This application also provides a method for preparing a microcatheter, which includes the following steps:

[0078] S1, Molded inner layer component 110

[0079] A tubular inner layer component 110 is formed using polytetrafluoroethylene as the raw material.

[0080] S2, Form intermediate layer component 120

[0081] The inner layer component 110 is straightened, and metal wires are first woven in a mesh pattern on the outer surface of the near end 101 of the inner layer component 110 to form braided wires 122. Spot welding is performed during the weaving process to make the braided wires 122 stably and tightly attached to the outer surface of the inner layer component 110. After the braided wires 122 are woven, metal wires are spirally wound on the outer surface of the inner layer component 110 near the far end 102 of the inner layer component 110 to form coiled wires 121 until they reach the far end 102 of the inner layer component 110. In the transition section between the coiled wires 121 and the braided wires 122, the braided wires 122 and the coiled wires 121 overlap. After the winding is completed, a heat shrink tube is placed on the outer sleeve of the intermediate layer component 120 for rheoforming, so that some of the braided wires 122 and / or the coiled wires 121 are embedded into the inner layer component 110.

[0082] S3, Fix the first developing ring 400 and the second developing ring 500.

[0083] Remove the heat shrink tubing, determine the positions of the first developing ring 400 and the second developing ring 500, first weld the reinforcing tube 600 to the position of the second developing ring 500 of the intermediate layer assembly 120 by heat fusion, and then fix the first developing ring 400 and the second developing ring 500 to the far end 102 of the outer surface of the intermediate layer assembly 120 by pressing, with the first developing ring 400 being closer to the far end 102 of the outer layer assembly 130 than the second developing ring 500, and the distance between the two ends of the reinforcing tube 600 and the corresponding ends of the second developing ring 500 is 0-1 cm.

[0084] S4, Prepare 100 tubes

[0085] The outer layer component 130 is fitted over the inner layer component 110, and the tube body 100 is placed inside the heat shrink tubing in a rheometer for rheological melting. During this process, the reinforcing tube 600 is fused with the outer layer component 130 through rheological means. This not only allows the tube bodies 100 to be interconnected and facilitates flow during rheological processes, but also allows the second developing ring 500 to be embedded between the reinforcing tube 600 and the outer layer component 130, thus producing the tube body 100.

[0086] S5, Forming a hydrophilic coating 140

[0087] A hydrophilic coating 140 slurry is coated on the outer surface of the outer component 130, and then the hydrophilic coating 140 is formed on the outer surface of the outer component 130 by means of photocuring, thermocuring or other methods.

[0088] S6, Assembly

[0089] The catheter seat 200, the protective sleeve 300 and the prepared tube body 100 are sequentially connected and assembled to form the microcatheter 10.

[0090] This application provides a microcatheter 10, which includes a tube body 100, a catheter seat 200, a protective sleeve 300, a first radiopaque ring 400, a second radiopaque ring 500, and a reinforcing tube 600. The protective sleeve 300 includes a first protective sleeve 310 and a second protective sleeve 320. One end of the first protective sleeve 310 and one end of the second protective sleeve 320 are connected, and the other end of the first protective sleeve 310 is connected to the end of the tube body 100. The other end of the second protective sleeve 320 is connected to the catheter seat 200. The catheter seat 200 has a main lumen 201, which can be used to accommodate microguidewires, drug injection devices, and therapeutic devices such as coils. The catheter seat 200 is made of polycarbonate. The tube body 100 has a feature close to the catheter. The catheter seat 200 has a proximal end 101 and a distal end 102 away from the catheter seat 200. The tube body 100 includes an inner layer assembly 110, an intermediate layer assembly 120, and an outer layer assembly 130 arranged sequentially from the inside to the outside. The inner layer assembly 110 has a tubular structure and an inner lumen 111 that communicates with the main lumen 201 of the catheter seat 200. The inner lumen 111 of the inner layer assembly 110 forms a delivery channel for delivering injectable drugs or instruments. The inner layer assembly 110 is made of polytetrafluoroethylene. The intermediate layer assembly 120 includes braided wires 122 located at the proximal end 101 and coiled wires 121 located at the distal end 102. The connection between the braided wires 122 and the coiled wires 121 is a transition section. In the transition section, the braided wires... 122 overlaps with the coiled wire 121. Both the coiled wire 121 and the braided wire 122 are made of stainless steel. The outer component 130 is a tubular structure. The outer component 130 is sleeved outside the inner component 110, and the outer component 130 and the inner component 110 are coaxially connected. The inner surface of the outer component 130 abuts against the intermediate component 120. A spiral channel for delivering contrast agent is formed between the inner component 110 and the outer component 130. The outer component 130 of the tube body 100 includes a first segment, a second segment, a third segment, and a fourth segment extending sequentially from the proximal end 101 to the distal end 102. The hardness of the first segment is 72D, the hardness of the second segment is 55D, the hardness of the third segment is 40D, and the hardness of the fourth segment is 35D. The component 130 is made of nylon, and the outer surface of the outer component 130 is also provided with a hydrophilic coating 140 including polyvinylpyrrolidone. The first developing ring 400 and the second developing ring 500 are both disposed between the intermediate layer component 120 and the outer layer component 130 at the distal end 102 of the tube body 100, and the first developing ring 400 is closer to the distal end 102 of the tube body 100 than the second developing ring 500. The reinforcing tube 600 is disposed between the intermediate layer component 120 and the second developing ring 500. The first developing ring 400 and the second developing ring 500 are both made of platinum-iridium alloy. The two ends of the reinforcing tube 600 extend 0.5 cm beyond the corresponding ends of the second developing ring 500. The reinforcing tube 600 is made of nylon.

[0091] In summary, the distal end 102 of the tube body 100 of the microcatheter 10 is used to extend into the human body, and the proximal end 101 of the tube body 100 is used to connect a therapeutic device or deliver diagnostic agents to the distal end 102 of the tube body 100. The microcatheter 10 of this application can improve the tensile strength at the second imaging ring 500 of the microcatheter 10 by providing a reinforcing tube 600 between the intermediate layer assembly 120 and the second imaging ring 500, thereby reducing the risk of the tube body 100 breaking at the second imaging ring 500 during use.

[0092] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A microcatheter, characterized in that, The microcatheter includes a tube body, a first radiopaque ring, a second radiopaque ring, and a reinforcing tube. The tube body includes an inner layer assembly, a middle layer assembly, and an outer layer assembly arranged sequentially from the inside to the outside. The tube body has a proximal end and a distal end. The middle layer assembly at the distal end of the tube body includes a coiled wire. The first radiopaque ring and the second radiopaque ring are both disposed between the middle layer assembly and the outer layer assembly at the distal end of the tube body, and the first radiopaque ring is closer to the distal end of the tube body than the second radiopaque ring. The reinforcing tube is disposed between the middle layer assembly and the second radiopaque ring and is connected to the outer layer assembly. The second radiopaque ring is embedded between the reinforcing tube and the outer layer assembly.

2. The microcatheter according to claim 1, characterized in that, The distance between the two ends of the reinforcing tube and the corresponding ends of the second developing ring is 0~1cm.

3. The microcatheter according to claim 1, characterized in that, The reinforcing tube is made of at least one of polyamide, nylon, and polyurethane.

4. The microcatheter according to claim 1, characterized in that, The reinforcing tube is made of the same material as the outer component.

5. The microcatheter according to any one of claims 1 to 4, characterized in that, The inner layer component is made of polytetrafluoroethylene.

6. The microcatheter according to any one of claims 1 to 4, characterized in that, The intermediate layer assembly at the proximal end of the tube body includes braided filaments.

7. The microcatheter according to claim 6, characterized in that, The intermediate layer component is made of metal.

8. The microcatheter according to claim 7, characterized in that, The metallic material includes at least one of stainless steel, nickel-titanium and tungsten.

9. The microcatheter according to any one of claims 1 to 4, characterized in that, The hardness of the outer layer assembly at the distal end of the tube is less than the hardness of the outer layer assembly at the proximal end of the tube.

10. The microcatheter according to any one of claims 1 to 4, characterized in that, The tube body also includes a hydrophilic coating, which is disposed on the outer surface of the outer component.

11. The microcatheter according to claim 10, characterized in that, The hydrophilic coating is made of materials including polyvinylpyrrolidone and / or polyacrylamide.

12. A method for preparing a microcatheter according to any one of claims 1 to 11, characterized in that, The method for preparing the microcatheter includes: winding the spring wire around the outer surface of the inner layer component to form the intermediate layer component; then, rheoforming a heat-shrinkable tube over the intermediate layer component; removing the heat-shrinkable tube; welding the reinforcing tube to the second imaging ring position of the intermediate layer component by heat fusion; then, fixing the first imaging ring and the second imaging ring to the distal end of the outer surface of the intermediate layer component by pressing, so that the reinforcing tube is positioned between the intermediate layer component and the second imaging ring; and finally, covering the inner layer component with the outer layer component.

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