Balloon micro catheter

Abstract

The utility model provides a balloon micro catheter, and relates to the technical field of medical instruments. A balloon micro catheter comprises a catheter, the catheter comprises an outer tube and an inner tube which are coaxially arranged, a first filling cavity is defined between the outer wall of the inner tube and the inner wall of the outer tube, and the inner tube is provided with a second filling cavity; the balloon is arranged at the far end of the catheter, and an inner cavity of the balloon is communicated with the first filling cavity; the balloon and the outer tube are integrally formed, and a far-end tube pin of the balloon is in close contact with the outer wall of the inner tube so that far-end plugging of the first filling cavity can be achieved. According to the balloon micro catheter, the outer tube and the balloon are integrally connected, the near end of the balloon does not need to be welded, the outer diameter increase of the connecting portion of the outer tube and the balloon is reduced through the integrated design, and therefore the balloon micro catheter can be more easily compatible with a small-specification angiographic catheter.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical devices, in particular to a balloon microcatheter. BACKGROUND

[0002] Hepatocellular carcinoma is one of the highest incidence of cancer, in addition to surgical resection, interventional therapy gradually become an important trend in the treatment of liver cancer. Traditional catheter arterial chemoembolization (TACE) is mainly through the microcatheter embolic agent directly into the tumor blood supply site, to block the blood supply of tumor, leading to tumor ischemia and hypoxia, inhibit its growth and promote tumor cell necrosis. However, the traditional TACE in the implementation process, there is a problem that embolic agent may reflux to normal liver tissue or flow into non-target organs, which limits its therapeutic effect.

[0003] Compared with traditional TACE, balloon occlusion TACE (B-TACE) uses balloon microcatheter in surgery, effectively avoids the reflux of embolic agent, and uses pressure gradient to achieve more dense iodine oil deposition, thereby improving the targeting and effectiveness of treatment. At present, the mainstream balloon microcatheter on the market is coaxial double lumen structure, which is divided into inner tube and outer tube. The inner tube is used as a microcatheter, responsible for passing through the guide wire and injecting embolic agent; the outer tube is connected with the balloon, and a filling cavity is designed on the catheter seat to fill the balloon by injecting contrast agent.

[0004] In the surgical process, the balloon microcatheter usually needs to be used in cooperation with the contrast catheter, so the requirements for the outer diameter and specifications of the tube body become more stringent. However, the connection mode of the outer tube and the balloon is mainly heat welding or laser welding, which usually adopts lap welding form, which inevitably leads to the increase of the outer diameter of the tube body, thereby affecting the compatibility of the balloon microcatheter and the contrast catheter, so that it cannot adapt to smaller size contrast catheters. At the same time, this welding method also limits the specification design of the inner tube, thereby affecting the overall pushability of the tube body and reducing the flexibility and efficiency of the surgery. UTILITY MODEL CONTENT

[0005] The purpose of the present application is to provide a balloon microcatheter which can effectively reduce the outer diameter of the tube body of the balloon microcatheter, thereby making it compatible with smaller size contrast catheters and improving the pushability of the tube body.

[0006] The present application provides a balloon microcatheter, which comprises a catheter, the catheter comprising an outer tube and an inner tube arranged coaxially, a first filling cavity being defined between the outer wall of the inner tube and the inner wall of the outer tube, the inner tube having a second filling cavity; a balloon arranged at the distal end of the catheter, the balloon lumen being in communication with the first filling cavity; the balloon is integrally formed with the outer tube, and the distal end pin of the balloon is in close contact with the outer wall of the inner tube to achieve the distal end blockage of the first filling cavity.

[0007] The balloon microcatheter comprises a catheter and a balloon, wherein the catheter adopts a coaxial design of an outer tube and an inner tube, and the balloon is made by an outer tube through a balloon forming machine, that is, the outer tube and the balloon are integrally formed, and the proximal end of the balloon does not need to be welded, so that the integrated design not only reduces the increase of the outer diameter of the connection part of the outer tube and the balloon, so that the balloon microcatheter can be more compatible with small-sized contrast catheters; the integrated design also optimizes the fluid flow path, reduces the flow resistance, and improves the fluid transmission efficiency when the balloon is inflated; in addition, the integrated connection of the outer tube and the balloon realizes the distal end sealing of the balloon inflation cavity, so that the fluid does not leak or seep during the inflation process, thereby enhancing the safety and reliability of the treatment.

[0008] In a possible implementation, the inner tube has a three-layer structure, including an inner liner, a metal braid layer and an outer layer; the inner liner is a polytetrafluoroethylene layer; the metal braid layer is any one of a stainless steel layer, a nickel-titanium layer or a tungsten layer; and the outer layer is any one of a polyamide layer, a polyimide layer, a polyurethane layer or a nylon layer.

[0009] The three-layer structure (the inner liner, the metal braid layer and the outer layer) of the inner tube provides good mechanical properties, in which the polytetrafluoroethylene inner liner has excellent chemical stability; the metal braid layer enhances the compression strength and is beneficial to the delivery of embolization spring coils, and the wire material is not easy to leak out of the inner tube, so as not to cause damage to the blood vessel wall; and the polymer material of the outer layer improves the overall flexibility and wear resistance, thereby ensuring the reliability of the microcatheter in a complex environment.

[0010] In a possible implementation, the hardness of the outer layer gradually decreases from the proximal end to the distal end.

[0011] The gradual decrease of the hardness of the outer layer from the proximal end to the distal end can make the balloon microcatheter gradually soft from the proximal end to the distal end, so as to balance the supportability of the proximal end and the flexibility of the distal end of the balloon microcatheter, which is beneficial to the passage of the balloon microcatheter through the tortuous blood vessels, and reduces the possibility of damage to the blood vessel wall, so as to facilitate the balloon microcatheter to reach the target position smoothly.

[0012] In a possible implementation, the inner tube is provided with a first developing ring and a second developing ring, the first developing ring is located at the distal end of the balloon, and the second developing ring is located inside the balloon.

[0013] The arrangement of the first developing ring and the second developing ring enables the doctor to clearly identify the position and state of the balloon during operation, thereby enhancing the convenience and safety of the catheter.

[0014] In a possible implementation, the first developing ring and the second developing ring are arranged between the metal braid layer and the outer layer.

[0015] The developing ring is arranged between the metal braided layer and the outer layer, so that the developing ring is not easy to fall off during use, the stability and safety of the overall structure are improved, and the use reliability of the catheter is increased.

[0016] In a possible implementation, the outer wall of the outer tube is provided with a hydrophilic coating.

[0017] The hydrophilic coating arranged on the surface of the outer tube can effectively reduce the friction, enhance the compliance of the catheter in the blood vessel, improve the smoothness of operation, and reduce the operation difficulty and risk.

[0018] In a possible implementation, the catheter seat is further arranged, the catheter seat is arranged at the proximal end of the catheter, and the catheter seat is provided with a first outer extension tube and a second outer extension tube; the lumen of the first outer extension tube is in communication with the first filling cavity through the first channel in the catheter seat, and the lumen of the second outer extension tube is in communication with the second filling cavity through the second channel in the catheter seat.

[0019] The catheter seat is arranged at the proximal end of the catheter, so that the main cavity and the side cavity can be effectively communicated with the channel of the inner tube, the guide wire passing and the drug injection are facilitated, and a reliable channel is also provided for the filling balloon.

[0020] In a possible implementation, the proximal ends of the inner tube and the outer tube are adhesively and fixedly connected to the catheter seat.

[0021] The proximal ends of the inner tube and the outer tube are fixed to the catheter seat by adhesion, the stability of the structure is enhanced, the displacement risk during use is reduced, and the use safety of the catheter is improved.

[0022] In a possible implementation, the first outer extension tube is coaxially arranged with the catheter, and the included angle between the second outer extension tube and the proximal end of the catheter is an obtuse angle.

[0023] The first outer extension tube is coaxially arranged with the catheter and forms an obtuse angle with the second outer extension tube, which helps to provide better fluid dynamics during operation, reduce flow resistance, and improve the patency of the catheter.

[0024] In a possible implementation, the stress protection sleeve is further arranged, the stress protection sleeve is sleeved at the distal end of the catheter seat, and the stress protection sleeve is detachably connected to the catheter seat.

[0025] The stress protection sleeve provides additional protection for the catheter seat, ensures that the catheter seat is not easy to be damaged during use, and is detachably connected to the catheter seat, so that the catheter is convenient to maintain and replace, and the use convenience of the catheter is improved. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be regarded as a limitation on the scope. Other related drawings can also be obtained by those of ordinary skill in the art without creative labor on the basis of these drawings.

[0027] Figure 1 The overall structure schematic diagram of the balloon microcatheter provided by the embodiments of the present application is shown in the figure.

[0028] Figure 2 The overall structure schematic diagram of the balloon microcatheter provided by the embodiments of the present application is shown in the figure. Figure 1 The cross-sectional view of A-A in the figure.

[0029] Figure 3 The local structure schematic diagram of the distal end of the balloon microcatheter provided by the embodiments of the present application is shown in the figure.

[0030] Figure 4 The local structure schematic diagram of the proximal end of the balloon microcatheter provided by the embodiments of the present application is shown in the figure.

[0031] Figure 5 The cross-sectional view of the outer tube and the balloon before forming provided by the embodiments of the present application is shown in the figure.

[0032] Figure 6 The cross-sectional view of the outer tube and the balloon after forming provided by the embodiments of the present application is shown in the figure.

[0033] Figure 7 The local structure schematic diagram of the proximal end of the balloon provided by the embodiments of the present application is shown in the figure.

[0034] Figure 8 The local structure schematic diagram of the proximal end of the balloon provided by the embodiments of the present application is shown in the figure. Figure 7 The enlarged view of B in the figure.

[0035] Figure 9 The local structure schematic diagram of the proximal end of the balloon provided by the embodiments of the present application is shown in the figure.

[0036] Figure 10 The local structure schematic diagram of the proximal end of the balloon provided by the embodiments of the present application is shown in the figure. Figure 9 The enlarged view of C in the figure.

[0037] Figure: 101-inner tube; 1011-inner liner; 1012-metal braid layer; 1013-outer layer; 102-outer tube; 1021-hydrophilic coating; 103-stress protection sleeve; 200-catheter seat; 201-first outer extension tube; 2011-first channel; 202-second outer extension tube; 2021-second channel; 300-balloon; 301-first filling cavity; 302-second filling cavity; 401-first developing ring; 402-second developing ring. DETAILED DESCRIPTION

[0038] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will be combined with the accompanying drawings for the embodiments of the present application to make a clear and complete description of the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. The components of the embodiments of the present application described and shown in the accompanying drawings can be arranged and designed in various different configurations.

[0039] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0040] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0041] In the description of the present application, it should be noted that the terms "proximal end" and "distal end" are medical field terms, specifically, the "proximal end" refers to the end closer to the operator of the microcatheter, and the "distal end" refers to the end farther away from the operator of the microcatheter.

[0042] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly placed when the product of the present application is used, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" and the like are only used for differentiation in description and cannot be understood as indicating or implying relative importance.

[0043] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components must be absolutely horizontal or overhanging, but can be slightly inclined. For example, "horizontal" only means that its direction is relatively more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0044] 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 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.

[0045] Example

[0046] Figure 1 This is a schematic diagram of the overall structure of the balloon 300 microcatheter provided in an embodiment of this application; Figure 2 for Figure 1 Sectional view at point AA; Figure 3 A partial structural diagram of the distal end of the balloon 300 microcatheter provided in an embodiment of this application; Figure 4 A schematic diagram of a partial structure of the proximal end of the balloon 300 microcatheter provided in an embodiment of this application; Figure 5 This is a cross-sectional view of the outer tube 102 and the balloon 300 before molding, as provided in the embodiments of this application. Figure 6 This is a cross-sectional view of the outer tube 102 and the balloon 300 after molding, as provided in an embodiment of this application. Figure 7 A partial structural diagram of the proximal end of the balloon 300 provided in an embodiment of this application; Figure 8 for Figure 7 Enlarged view of point B in the middle; Figure 9 A partial structural diagram of the proximal end of the balloon 300 when the balloon 300 and the outer tube 102 are fixed by welding according to an embodiment of this application; Figure 10 for Figure 9 A magnified view of point C; please refer to... Figures 1-10 .

[0047] This embodiment provides a balloon 300 microcatheter, comprising: a catheter, the catheter including an outer tube 102 and an inner tube 101 coaxially arranged, a first filling cavity 301 defined between the outer wall of the inner tube 101 and the inner wall of the outer tube 102, and the inner tube 101 having a second filling cavity 302; a balloon 300 disposed at the distal end of the catheter, the inner lumen of the balloon 300 communicating with the first filling cavity 301; the balloon 300 is integrally formed with the outer tube 102, and the distal end of the balloon 300 is in close contact with the outer wall of the inner tube 101 to achieve distal occlusion of the first filling cavity 301.

[0048] like Figure 1 and Figure 2As shown, the catheter employs a coaxial design with an outer tube 102 and an inner tube 101. A first filling cavity 301 is formed between the outer wall of the inner tube 101 and the inner wall of the outer tube 102. This structure enhances the overall stability and fluid delivery efficiency of the catheter. The filling cavity design allows for effective pressure transmission during balloon 300 inflation, enabling rapid inflation and accurate positioning of the balloon 300, thereby improving the success rate of interventional treatment. The balloon 300 is positioned at the distal end of the catheter, with its inner lumen communicating with the first filling cavity 301. Furthermore, the outer tube 102 and the balloon 300 are integrally formed, eliminating the need for welding at the proximal end of the balloon 300. This integrated design not only reduces the increase in outer diameter at the connection point between the outer tube 102 and the balloon 300, making the balloon 300 microcatheter more compatible with smaller angiography catheters, but also optimizes the fluid flow path, reduces flow resistance, and improves the fluid transmission efficiency during balloon 300 inflation. The distal end of the outer tube 102 is in close contact with the outer wall of the inner tube 101, achieving distal sealing of the first filling lumen 301 and effectively preventing fluid leakage. This design not only reduces potential risks during operation but also improves the precision of treatment. Furthermore, the inner tube 101 features a second filling lumen 302, providing the catheter with greater functional flexibility, enabling various operations during treatment, such as simultaneous drug injection or contrast agent delivery. This dual-lumen design makes the catheter more adaptable in practical applications and can meet diverse clinical needs.

[0049] like Figure 2 As shown, the inner tube 101 of the catheter has a three-layer structure, consisting of an inner liner 1011, a metal braided layer 1012, and an outer layer 1013. The inner liner 1011 is a polytetrafluoroethylene (PTFE) layer; the metal braided layer 1012 is any one of a stainless steel layer, a nickel-titanium layer, or a tungsten layer; and the outer layer 1013 is any one of a polyamide layer, a polyimide layer, a polyurethane layer, or a nylon layer. This three-layer structure (inner liner 1011, metal braided layer 1012, and outer layer 1013) provides it with excellent mechanical properties. The PTFE inner liner 1011 possesses excellent chemical stability, ensuring reliability in complex environments; the metal braided layer 1012 enhances the catheter's compressive strength, effectively supporting the delivery of the embolization coil and preventing damage to the vessel wall; while the outer layer 1013 material (such as polyamide or polyurethane) improves overall flexibility and abrasion resistance, making the catheter easier to push.

[0050] The outer layer 1013 is divided into five segments with different hardness and length from distal to proximal end, namely 35D, 40D, 55D, 63D, and L25. The outer tube 102 is fabricated into a balloon 300 in the 63D segment using a balloon 300 forming machine. The balloon 300 is a compliant balloon 300, and the balloon 300 and the outer tube 102 are an integral structure (see reference). Figure 5 and Figure 6), the distal end of the outer tube 102 is fixedly connected to the 35D section on the outer layer 1013 of the inner tube 101, and the connection mode can be heat welding, laser welding, bonding, etc. D: usually refers to the durometer (Shore durometer), which is a standard for measuring the hardness of materials such as plastics and rubbers. The larger the number, the harder the material. That is, the hardness of the outer layer 1013 gradually decreases from the proximal end to the distal end, so that the balloon 300 microcatheter maintains supportability at the proximal end while the distal end has better flexibility. This design helps the catheter to smoothly pass through the tortuous blood vessels, reduces the possibility of damage to the blood vessel wall, and effectively improves the pushing performance of the catheter.

[0051] As an example, the five sections of the outer layer 1013 with different hardnesses can be welded by hot melting, laser welding, or a combination thereof; the three-layer structure of the inner tube 101 can be fused by rheology.

[0052] The outer tube 102 is a single-layer structure, and the material of the outer tube 102 includes but is not limited to polyamide (Pebax), nylon (PA), polyurethane (TPU), and other polymer materials. The outer tube 102 is composed of the balloon 300 at the distal end and the outer tube 102 body. The balloon 300 is made by balloon 300 forming of the outer tube 102, so the outer tube 102 and the balloon 300 are integrally formed.

[0053] The outer wall of the outer tube 102 is provided with a hydrophilic coating 1021, which can effectively reduce the friction of the catheter in the blood vessel, enhance the compliance of the catheter, and thus improve the smoothness and comfort of the operation, so that the balloon 300 microcatheter is more efficient in the process of puncture and introduction, and the operation difficulty and risk are reduced.

[0054] As an example, the material of the hydrophilic coating 1021 includes but is not limited to polyvinylpyrrolidone (PVP), polyacrylamide (PAM), and other polymer materials. The hydrophilic coating 1021 can be coated on the outer wall of the outer tube 102 by light curing, thermal curing, etc.

[0055] As shown in Figure 3 , the inner tube 101 is provided with a first developing ring 401 and a second developing ring 402. The first developing ring 401 is located at the distal end of the balloon 300, and the second developing ring 402 is located inside the balloon 300. This design enables the doctor to clearly identify the position and state of the balloon 300 during operation, increasing the convenience and safety of the catheter. At the same time, the setting position of the developing ring ensures that it is not easy to fall off during use, further improving the overall structural stability of the catheter.

[0056] The material of the first developing ring 401 and the second developing ring 402 includes, but is not limited to, gold, platinum-iridium alloy, platinum-tungsten alloy or a combination thereof. The first developing ring 401 and the second developing ring 402 can be arranged between the metal braided layer 1012 and the outer layer 1013 by pressing or forging.

[0057] As shown in Figure 4 , the balloon 300 catheter further includes a catheter seat 200 arranged at the proximal end of the catheter. The catheter seat 200 is provided with a first outer extension tube 201 and a second outer extension tube 202. The lumen of the first outer extension tube 201 communicates with the first inflation cavity 301 through the first channel 2011 in the catheter seat 200, and the lumen of the second outer extension tube 202 communicates with the second inflation cavity 302 through the second channel 2021 in the catheter seat 200. The design of the catheter seat 200 is connected with the proximal end of the catheter, so that the first outer extension tube 201 can communicate with the inner cavity of the balloon 300 (the first inflation cavity 301), which is convenient for inflating the balloon 300 by filling gas or liquid; the second outer extension tube 202 can communicate with the channel of the inner tube 101 (the second inflation cavity 302), which is convenient for the passage of the guide wire and the injection of drugs.

[0058] In the embodiment of the present application, the proximal end of the inner tube 101 and the outer tube 102 is fixed on the catheter seat 200 by adhesive bonding, which enhances the stability of the structure, reduces the risk of displacement during use, and improves the safety of the catheter.

[0059] In the embodiment of the present application, the first outer extension tube 201 is coaxially arranged with the catheter, and the included angle between the second outer extension tube 202 and the proximal end of the catheter is obtuse. The coaxial arrangement of the first outer extension tube 201 and the catheter makes the axis of the first outer extension tube 201 coincide with the axis of the catheter, so that the fluid can flow uniformly in the same direction, reducing the formation of turbulent flow and vortex flow, thereby reducing the flow resistance. The coaxial design can also reduce the sharp turns and sudden changes in fluid flow, which can improve the flow efficiency of the fluid and reduce energy loss. When the included angle between the second outer extension tube 202 and the catheter is obtuse, the fluid flowing through this connection point will not encounter a sharp turn, but will flow at a gradually changing angle. This design can make the fluid flow path smoother, reducing the impact and disturbance on the fluid. The obtuse angle design can also reduce the resistance of fluid flow, because the velocity and pressure change of the fluid at the corner is small, and the flow is more stable, thereby reducing the overall flow resistance.

[0060] In the embodiment of the present application, the distal end of the catheter seat 200 is provided with a stress protection sleeve 103, and the stress protection sleeve 103 is detachably connected with the catheter seat 200. As an example, the catheter seat 200 is provided with a boss, and the stress protection sleeve 103 is provided with a groove, and the boss and the groove are matched.

[0061] Continuing to refer to Figures 7-10 , Figure 7 andFigure 8 It can be seen that when the balloon 300 is welded with the outer tube 102, the maximum outer diameter of the balloon 300 microcatheter is equal to the outer diameter H' of the balloon 300 proximal welding point position, and H' is greater than the outer diameter H of the outer tube 102; therefore, in the balloon 300 microcatheter provided by the application, the balloon 300 proximal end does not need to be welded, which can effectively reduce the outer diameter of the tube body, and further make the product compatible with smaller size contrast catheters. Figure 9 and Figure 10 It can be seen that when the balloon 300 is welded with the outer tube 102, the maximum outer diameter of the balloon 300 microcatheter is equal to the outer diameter H' of the balloon 300 proximal welding point position, and H' is greater than the outer diameter H of the outer tube 102; therefore, in the balloon 300 microcatheter provided by the application, the balloon 300 proximal end does not need to be welded, which can effectively reduce the outer diameter of the tube body, and further make the product compatible with smaller size contrast catheters.

[0062] In summary, the balloon 300 microcatheter provided by the application has coaxial structure, filling cavity design and integrated connection, which not only improves the stability and use efficiency of the catheter, but also enhances the precision and flexibility of the treatment, and significantly improves the overall effect of the interventional treatment.

[0063] The above only describes the preferred embodiments of the application and is not intended to limit the application. Those skilled in the art can make various modifications and changes to the application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. A balloon microcatheter, characterized by, The catheter comprises an outer tube and an inner tube arranged coaxially, a first inflation cavity is defined between the outer wall of the inner tube and the inner wall of the outer tube, and the inner tube has a second inflation cavity. A balloon is arranged at the distal end of the catheter, and a balloon lumen is in communication with the first inflation cavity; the balloon is integrally formed with the outer tube, and the distal tube foot of the balloon is in close contact with the outer wall of the inner tube to achieve distal sealing of the first inflation cavity. The inner tube has a three-layer structure, including an inner liner, a metal braid layer, and an outer layer; the inner liner is a polytetrafluoroethylene layer; the metal braid layer is any one of a stainless steel layer, a nickel-titanium layer, or a tungsten layer; and the outer layer is any one of a polyamide layer, a polyimide layer, a polyurethane layer, or a nylon layer.

2. The balloon microcatheter of claim 1, wherein, The hardness of the outer layer gradually decreases from the proximal end to the distal end.

3. The balloon microcatheter of claim 2, wherein, The inner tube is provided with a first developing ring and a second developing ring, the first developing ring is located at the distal end of the balloon, and the second developing ring is located inside the balloon.

4. The balloon microcatheter of claim 2, wherein, The first developing ring and the second developing ring are arranged between the metal braid layer and the outer layer.

5. The balloon microcatheter of claim 4, wherein, The outer wall of the outer tube is provided with a hydrophilic coating.

6. The balloon microcatheter of any of claims 1-5, wherein, The catheter seat is arranged at the proximal end of the catheter, and the catheter seat is provided with a first outer extension tube and a second outer extension tube; the lumen of the first outer extension tube is in communication with the first inflation cavity through a first channel in the catheter seat, and the lumen of the second outer extension tube is in communication with the second inflation cavity through a second channel in the catheter seat.

7. The balloon microcatheter of any of claims 1-5, wherein, The proximal ends of the inner tube and the outer tube are adhesively and fixedly connected to the catheter seat.

8. The balloon microcatheter of claim 7, wherein, The first outer extension tube is coaxially arranged with the catheter, and the included angle between the second outer extension tube and the proximal end of the catheter is obtuse.

9. The balloon microcatheter of claim 7, wherein, The stress protection sleeve is detachably connected to the catheter seat.

10. The balloon microcatheter of claim 9, wherein, ​

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