A balloon catheter and its preparation method

Abstract

The present invention provides a balloon catheter and a preparation method thereof. The balloon catheter includes a distal tube, an inner lumen tube, a balloon body and an outer tube, wherein: the distal tube includes a distal end portion and a connecting portion connected axially, the distal end portion is located at the distal end of the connecting portion, the distal tube includes a housing and a support layer, the housing extends at least from the distal end portion to the connecting portion, the support layer is at least partially located at the connecting portion and the support layer is located inside the housing; the inner lumen tube penetrates through the balloon body and is connected to the proximal end of the distal tube; the distal end of the balloon body is fixed at the connection between the inner lumen tube and the distal tube, on the distal tube or on the inner lumen tube, and the proximal end of the balloon body is connected to the distal end of the outer tube. The distal outer diameter of the distal tube of the balloon catheter of the present invention is small, a support layer is added in the distal tube, and it is not easily deformed, which can improve the passing ability of the balloon catheter during the operation of treating intracranial vascular stenosis and the ability to enter the lesion location.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and particularly to a balloon catheter and a preparation method thereof. Background Art

[0002] Ischemic stroke is mainly caused by vascular stenosis or occlusion, hemodynamic or blood component changes, resulting in insufficient oxygen and nutrient carrying capacity of the blood or reduced ability to remove metabolic products, leading to the death of brain neurons, glial cells, and blood vessels. Ischemic stroke accounts for about 80% of cerebrovascular diseases. Among them, cerebrovascular stenosis is an important cause and risk factor for ischemic cerebrovascular diseases. Currently, the main treatment methods for cerebrovascular stenosis are: (i) drug treatment, combining drugs such as antiplatelet aggregation or lipid-lowering drugs to delay the progression of carotid stenosis and improve cerebrovascular reactivity; (ii) extracranial-intracranial bypass: for symptomatic intracranial stenosis patients with severe hemodynamic disorders, extracranial-intracranial bypass may improve cerebral tissue engineering or reduce the recurrence rate of stroke; (iii) endovascular treatment: for symptomatic intracranial stenosis greater than or equal to 70% that is ineffective with the best drugs or has poor cerebral collateral circulation compensation, balloon angioplasty or stent implantation is used to dilate the stenosed blood vessel to restore the vascular access. Generally, the intracranial stenosed blood vessels are relatively tortuous and complex, with small blood vessel diameters and thin blood vessel walls, and are prone to spasm and dissection during the operation. Moreover, the stenosed sites are located at the more distal parts of the blood vessels, such as C6 and C7 (ophthalmic segment and communicating segment), M1 and M2 (horizontal segment (posterior orbital segment) of the middle cerebral artery and gyral segment (insula segment) of the middle cerebral artery). Therefore, a balloon catheter with better imaging effect is needed to facilitate doctors to adjust the balloon catheter in a timely manner during the operation, reduce the damage of the balloon catheter to the blood vessel, shorten the operation time, and improve the treatment effect.

[0003] Among the currently marketed balloon catheters, the position of the balloon main body is mainly judged by the metal imaging ring on the inner cavity tube of the balloon, but the position of the distal end of the balloon catheter cannot be judged, which easily leads to the doctor being unable to adjust the distal end in a timely manner when encountering a bifurcation site or resistance during the operation, resulting in blood vessel damage and prolonged operation time. Moreover, the distal ends of most current balloon catheters are made of polymer materials, which are prone to deformation when encountering greater resistance, affecting the delivery, placement, and withdrawal capabilities of the balloon catheter. Summary of the Invention

[0004] Aiming at the problems in the prior art, the purpose of the present invention is to provide a balloon catheter and a preparation method thereof. The distal outer diameter of the distal end tube of the balloon catheter is small, and a support layer is added to the distal end tube, making it not easily deformable, and improving the delivery, placement, and withdrawal capabilities of the balloon catheter.

[0005] The present invention provides a balloon catheter, which comprises a distal tube, an inner lumen tube, a balloon body and an outer tube, wherein: the distal tube comprises a distal end portion and a connecting portion which are axially connected, the distal end portion is located at the distal end of the connecting portion, and the outer diameter of the distal end of the distal end portion is smaller than the outer diameter of the connecting portion. The distal tube comprises a housing and a support layer. The housing extends at least from the distal end portion to the connecting portion. The support layer is at least partially located at the connecting portion and is located inside the housing; the inner lumen tube penetrates through the balloon body and is connected to the proximal end of the distal tube; the distal end of the balloon body is fixed at the connection between the inner lumen tube and the distal tube, on the distal tube or on the inner lumen tube, and the proximal end of the balloon body is connected to the distal end of the outer tube.

[0006] In some embodiments, the housing located at the distal end portion has a tapered structure with an outer diameter gradually increasing from the distal end to the proximal end.

[0007] In some embodiments, the distal end portion of the distal tube is a single-layer structure only including the housing.

[0008] In some embodiments, the outer diameter of the distal end of the distal end portion of the distal tube is 0.0155 inches - 0.018 inches, the inner diameter of the distal end of the distal end portion of the distal tube is 0.0150 inches - 0.0157 inches, and the length of the distal end portion of the distal tube is 0.2 mm - 1.5 mm.

[0009] In some embodiments, the distal tube further comprises a proximal end portion located at the proximal end of the connecting portion. The housing extends from the distal end portion to the proximal end portion, and the distal end of the inner lumen tube extends into the inside of the housing at the proximal end portion of the distal tube.

[0010] In some embodiments, the support layer comprises a metal spring or a metal braided structure.

[0011] In some embodiments, the metal spring or the metal braided structure comprises metal wires, and the material of the metal wires comprises one or more of platinum, tungsten, tantalum, platinum-iridium alloy, platinum-nickel alloy, platinum-tungsten alloy, platinum-tantalum alloy or gold.

[0012] In some embodiments, the size of the metal wires is 0.00075 inches - 0.003 inches.

[0013] In some embodiments, the outer diameter of the distal end of the metal spring or the metal braided structure is smaller than or equal to the outer diameter of the proximal end of the metal spring or the metal braided structure.

[0014] The present invention provides a method for manufacturing the balloon catheter as described above, which comprises the following steps:

[0015] Provide an operating wire, and fabricate through the support layer around the operating wire;

[0016] Provide the inner lumen tube, pass the operating wire through the inner lumen tube, and abut the proximal end of the support layer against the distal end of the inner lumen tube;

[0017] Put a housing on the outer periphery of the distal ends of the support layer and the inner lumen tube, and make the housing at least extend to cover the support layer, so as to form a connection part of the terminal tube at a position corresponding to the support layer;

[0018] Provide one of the balloon bodies and one of the outer tubes, fix the distal end of the balloon body at the connection of the inner lumen tube and the terminal tube, on the terminal tube or on the inner lumen tube, and connect the proximal end of the balloon body to the distal end of the outer tube;

[0019] Connect the support layer, the inner lumen tube, the housing, the balloon body and the outer tube into one body by laser welding.

[0020] In some embodiments, the distal end of the operating wire has a tapered structure with an outer diameter gradually increasing from the distal end to the proximal end.

[0021] In some embodiments, making the housing extend to cover the support layer includes: making the housing extend out of the distal end of the support layer to form a distal end part of the terminal tube at a position corresponding to only the housing; and / or,

[0022] Making the distal end of the inner lumen tube extend into the proximal end of the inner side of the housing to form a proximal end part of the terminal tube at a position corresponding to the distal end of the inner lumen tube.

[0023] In some embodiments, making the support layer around the operating wire includes:

[0024] Provide at least one metal wire, helically wind the metal wire around the distal end of the operating wire to form a metal spring, or braid the metal wire at the distal end of the operating wire to form a metal braided structure.

[0025] In some embodiments, the metal wire is made of one or a combination of platinum, tungsten, tantalum, platinum-iridium alloy, platinum-nickel alloy, platinum-tungsten alloy, tungsten-platinum alloy or gold.

[0026] The balloon catheter and its preparation method provided by the present invention have the following advantages: the distal outer diameter of the terminal tube of the balloon catheter is small, a support layer is added in the terminal tube, it is not easy to deform, and the passing performance of the balloon catheter during the treatment of intracranial vascular stenosis surgery and the ability to enter the lesion position can be improved, and the success rate of the surgery can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Other features, objects and advantages of the present invention will become more apparent by reading the detailed description of the non-limiting embodiments with reference to the following drawings.

[0028] Figure 1 is a schematic structural diagram of a balloon catheter according to an embodiment of the present invention;

[0029] Figure 2 is a schematic structural diagram of Example 1 of the balloon catheter of the present invention and an operating wire for preparing the same;

[0030] Figure 3 is a flow chart of a method for preparing a balloon catheter assembly according to an embodiment of the present invention;

[0031] Figure 4 is a schematic structural diagram of Example 2 of the balloon catheter of the present invention and an operating wire for preparing the same;

[0032] Figure 5 The present invention Figure 4 A schematic diagram of the structure of the middle support layer is enlarged;

[0033] Figure 6 Schematic diagram of the structure of Example 3 of the balloon catheter of the present invention and an operating wire for preparing the same.

[0034] Reference numerals:

[0035] 11 Balloon body 14 Outer tube

[0036] 12 Inner cavity tube 15 Diffusion stress tube

[0037] 122 distal end of inner lumen tube 16 base

[0038] 13 End tube 17 Operating wire

[0039] 131 distal end 18 hypotube

[0040] 132 Connection A Distal end of metal spring

[0041] 133 Proximal end B Proximal end of the metal spring

[0042] 13a Metal spring

[0043] 13b Housing DETAILED DESCRIPTION

[0044] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. Like reference numerals in the figures denote like or similar structures, and thus their repetitive description will be omitted. "Or" or "alternatively" in the specification may mean "and" or "or". In the present invention, the distal end and the proximal end are relative to the operator. The end closer to the operator is the proximal end, and the end farther from the operator is the distal end.

[0045] To solve the technical problems in the prior art, the present invention provides a balloon catheter, which includes a distal tube, an inner lumen tube, a balloon body, and an outer tube. The distal tube includes a distal portion and a connecting portion that are axially connected. The distal portion is located at the distal end of the connecting portion, and the outer diameter of the distal end of the distal portion is smaller than the outer diameter of the connecting portion, thereby ensuring the smallest outer diameter for introducing into the lesion position, and improving the passability, trackability, and the ability to penetrate into the lesion position of the balloon catheter. The distal tube includes a housing and a support layer. The housing extends at least from the distal portion to the connecting portion. The support layer is at least partially located in the connecting portion and is located inside the housing, which can provide support for the housing, prevent the deformation of the distal tube lumen, is more conducive to passing through tortuous diseased blood vessels, and at the same time improves the ability to maintain the distal end shape. Further, the distal tube further includes a proximal portion located at the proximal end of the connecting portion. The housing extends from the distal portion to the proximal portion. The distal end of the inner lumen tube extends into the inside of the housing at the proximal portion of the distal tube. The inner lumen tube penetrates through the balloon body and is connected to the proximal end of the distal tube. The distal end of the balloon body is fixed at the connection between the inner lumen tube and the distal tube, on the distal tube, or on the inner lumen tube. The proximal end of the balloon body is connected to the distal end of the outer tube. The present invention also provides a preparation method for preparing the balloon catheter including the balloon catheter.

[0046] The balloon catheter and the preparation method of the balloon catheter of the present invention will be specifically introduced below in conjunction with the accompanying drawings and each embodiment.

[0047] Example 1

[0048] Figure 1 is a schematic diagram of the balloon catheter of Example 1 and the operating wire for preparing it, Figure 2 is a schematic diagram of the balloon catheter assembly of Example 1. From Figure 1 and Figure 2It can be seen that the balloon catheter 10 includes a terminal tube 13, which includes a distal portion 131, a connecting portion 132 and a proximal portion 133 arranged in sequence from the distal end to the proximal end, and the outer diameter of the distal end of the distal portion 131 is smaller than the outer diameter of the connecting portion 132 to ensure that the smallest outer diameter is introduced into the lesion position. The terminal tube 13 includes a shell 13b and a support layer, the shell 13b extends from the distal end 131 of the terminal tube 13 to the proximal end 133, the support layer is located at the connecting portion 132 and the support layer is located on the inner side of the shell 13b to support the shell 13b; and an inner lumen tube 12 and a balloon body 11, the inner lumen tube 12 passes through the balloon body 11 and is connected to the proximal end of the terminal tube 13. The inner lumen tube 12 and the terminal tube 13 can be extruded as a whole or connected by laser, hot pressing, etc. Figure 1 The balloon catheter 10 further includes an outer tube 14, the distal end of the balloon body 11 is fixed to the connection between the inner tube 12 and the terminal tube 13, the terminal tube 13 or the inner tube 12, and the proximal end of the balloon body 11 is fixed to the distal end of the outer tube 14. In addition, Figure 1 As shown in the figure, the balloon catheter 10 further includes a diffusion stress tube 15 , a hypotube 18 between the outer tube 14 and the diffusion stress tube 15 , and a base 16 .

[0049] The terminal tube 13 may include a single layer or a multi-layer structure, or may include both a single layer and a multi-layer structure. In this embodiment, the distal end portion 131 is a single layer structure including only a shell. The shell 13b may be formed of a polymer material, for example. Figure 2 The distal end portion 131 is a single-layer polymer material, and the connecting portion 132 and the proximal end portion 133 may be a double-layer or multi-layer structure, preferably a double-layer structure. For example, the connecting portion 132 includes a shell 13b and the support layer, and the distal end 122 of the inner cavity tube 12 at least partially enters the inner side of the shell 13b at the proximal end portion 133 of the terminal tube 13, so that the proximal end portion 133 forms a double-layer structure. Figure 2It can be obtained that the housing 13b at the distal end has a tapered structure with an outer diameter gradually increasing from the distal end to the proximal end at the distal end portion 131, and the outer surface of the distal end portion 131 is a smooth surface. Through the design of the single-layer tapered structure at the farthest end of the balloon catheter, it ensures the smallest outer diameter for lesion introduction, a suitable inner diameter for good wire fitting, improves the passing ability, tracking ability of the balloon catheter and the ability to penetrate into the lesion location, and at the same time is less likely to damage blood vessels. Specifically, the outer diameter of the distal end of the distal end portion 131 of the terminal tube 13 is 0.0155 inches - 0.018 inches, preferably 0.0160 inches - 0.0170 inches, and the inner diameter of the distal end of the distal end portion 131 of the terminal tube 13 is 0.0150 inches - 0.0157 inches; the length of the distal end portion 131 of the terminal tube 13 is 0.2 mm - 1.5 mm, preferably 0.5 mm - 0.8 mm. The various dimensions given here are only examples. In other alternative embodiments, the various dimensions can be selected or adjusted as needed, and are not limited to those listed here.

[0050] Figure 2The support layer shown in [Figure] is a metal spring 13a formed by helically winding metal wires. In another alternative embodiment, the metal spring 13a can also be a metal braided structure formed by braiding metal wires. The support layer can include one layer of metal spring or multiple layers of metal springs, or the support layer can include one layer of metal braided structure or multiple layers of metal braided structures, or the support layer can also include a combination of at least one layer of metal spring or at least one layer of metal braided structure. In this embodiment, by using a metal spring or a metal braided structure as the support layer at the connecting portion 132, while ensuring the end flexibility, it can provide support for the polymer outer layer, preventing the end tube 13 from deforming when encountering resistance or passing through tortuous blood vessels, thereby reducing the deliverability, positioning ability, and withdrawal performance of the balloon catheter. In this embodiment, the support layer is taken as the metal spring 13a for illustration. The metal spring 13a is a cylindrical spring, that is, the outer diameter of the distal end of the metal spring 13a is equal to the outer diameter of the proximal end of the metal spring 13a. And the outer diameter of the metal spring 13a is equal to the inner diameter of the housing 13b at the connecting portion 132 of the end tube 13. The metal spring 13a includes metal wires, and the metal wire material is preferably a radiopaque material with a high X-ray attenuation coefficient. For example, the metal wire material is preferably one or more of platinum, tungsten, tantalum, platinum-iridium alloy, platinum-nickel alloy, platinum-tungsten alloy, tungsten-tantalum alloy, tungsten-tantalum alloy, and gold. The metal wire with a high X-ray attenuation coefficient can be flat wire, round wire, or special-shaped wire. The material selected for the metal spring is a metal wire material with a high X-ray attenuation coefficient, which can increase the radiography function of the end of the balloon catheter, facilitate the doctor to adjust the position of the end in time according to needs, and reduce the surgical operation time. The radial dimension of the metal wire is 0.00075 inches - 0.003 inches, preferably 0.001 inches - 0.00175 inches. In other alternative embodiments, when the support layer is a metal braided structure, the material and size of the metal wires used in the metal braided structure can be the same as those of the metal wires of the metal spring 13a above. The housing 13b is made of a polymer, and the polymer can be polyamide or thermoplastic elastomeric polyurethane, or a radiopaque material such as bismuth oxide, barium sulfate, or tungsten powder is added to the polymer. As described above, the proximal end portion 133 is also a double-layer structure. The inner layer is the distal end 122 of the inner lumen tube 12, and the outer layer is an extension section of the outer layer 13b of the connecting portion 132 of the end tube 13, that is, the distal end portion 131, the housing 13b, and the extension of 13b are integrated and made of the same pipe material.

[0051] According to Figure 2 , the preparation method of the balloon catheter can also be obtained, and the method is as Figure 3 shown. From Figure 2It can also be obtained that an operating wire 17 is threaded through the inner cavity tube 12 and the end tube 13. The outer diameter of the distal end of the operating wire 17 is equal to the outer diameter of the proximal end of the operating wire 17, and the outer diameter of the distal end of the metal spring 13a in the balloon catheter 10 is equal to the inner diameter of the housing 13b at the connection portion 132.

[0052] Figure 3 The preparation method of the balloon catheter described therein includes the following steps:

[0053] S100: Provide an operating wire 17 and fabricate the support layer around the operating wire 17;

[0054] Specifically, fabricating the support layer around the operating wire 17 includes: providing at least one metal wire and helically winding the metal wire around the distal end of the operating wire to form a metal spring or a metal braided structure.

[0055] S200: Provide the inner cavity tube 12, thread the operating wire 17 through the inner cavity tube 12, and make the proximal end of the support layer abut against the distal end of the inner cavity tube 12;

[0056] S300: Sheath the housing 13b on the outer periphery of the support layer and the distal end of the inner cavity tube 12, and make the housing 13b at least extend to cover the support layer so as to at least form the connection portion 132 of the end tube 13 at the position corresponding to the support layer 13a;

[0057] Specifically, making the housing 13b extend to cover the support layer includes: even making the housing 13b extend beyond the distal end of the support layer to form the distal end portion of the end tube at the position corresponding to only the housing; and / or making the distal end of the inner cavity tube extend into the proximal end of the inner side of the housing to form the proximal end portion of the end tube at the position corresponding to the distal end of the inner cavity tube.

[0058] Specifically, the support layer, the inner cavity tube 12, and the housing 13b can be combined together by laser, or by hot pressing or bonding, etc. In this embodiment, the laser processing method is adopted.

[0059] S400: Provide the balloon body 11 and an outer tube, fix the distal end of the balloon body 11 at the connection of the inner cavity tube 12 and the end tube 13, on the end tube 13, or on the inner cavity tube 12, and connect the proximal end of the balloon body 11 to the distal end of the outer tube 13;

[0060] Specifically, a laser processing method can be adopted. Finally, the distal end of the balloon body 11 is fixed at the connection part between the connection part 132 and the proximal end part 133 of the end tube 13, or fixed at the proximal end of the proximal end part 133 of the end tube 13, that is, the distal end of the balloon body 11 is flush with the end tube 13.

[0061] S500: Finally, the support layer, the inner cavity tube 12, the housing 13b, the balloon body 11 and the outer tube 14 are connected into one body by laser welding.

[0062] S600: By adjusting the laser process parameters of the distal end part 131 of the housing 13b, the distal end part 131 of the housing 13b is formed into a conical shape with an outer diameter gradually increasing from the distal end to the proximal end. The conical design on the housing is more conducive to passing through narrow lesions and can also improve the fitting degree between the end and the guide wire inserted into the inner cavity, improving the tracking performance of the balloon catheter.

[0063] Embodiment 2

[0064] Figure 4 It is a schematic structural diagram of Embodiment 2 of the balloon catheter assembly and with an operating wire for preparing it. Compared with Figure 2 in, the difference is that the support layer on the inner layer of the connection part 132 of the end tube 13 is a developable metal spring with a taper, that is, the distal end A of the metal spring 13a has a conical structure with an outer diameter gradually increasing towards the proximal end B, the outer diameter of the distal end A of the metal spring is smaller than the outer diameter of the proximal end B of the metal spring, and the enlarged view of the metal spring 13a is as shown in Figure 5 shown. The developable metal spring 13a with a taper can help to form the taper of the distal end part 131 of the end tube 13. The conical design on the housing 13b is more conducive to passing through narrow lesions and can also improve the fitting degree between the end and the guide wire, improving the tracking performance of the balloon catheter.

[0065] When preparing the balloon catheter 10 of this embodiment, the preparation method steps of the balloon catheter shown in Figure 3 can also be adopted for obtaining. Different from Figure 2 in, according to the operating wire 17, a support layer with a conical structure from the distal end to the proximal end is wound. The formation of the support layer with a taper is conducive to better forming a conical structure at the distal end part 131 of the end tube 13, reducing the process difficulty of forming the distal end part 131.

[0066] Embodiment 3

[0067] Figure 6 It is a schematic structural diagram of another embodiment of the balloon catheter and with an operating wire for preparing it. Compared with Figure 4Different from the balloon catheter shown, the outer diameter of the distal end to the proximal end of the operating wire 17 also has a gradually increasing structure. The tapered design of the operating wire 17 is beneficial to form the taper of the distal end 131 of the terminal tube 13 and the support layer, and is also convenient for processing the balloon catheter 10.

[0068] The balloon catheter of this Embodiment 3 can also be obtained by Figure 3 the steps of the preparation method of the balloon catheter shown in, and at the same time, the tapered operating wire can reduce the process difficulty of making the tapered support layer, thereby reducing the processing difficulty of making the balloon catheter.

[0069] In summary, the balloon catheter and the preparation method of the balloon catheter provided by this embodiment have the following advantages: Through the single-layer tapered structure design at the farthest end of the balloon catheter, the passability, trackability and the ability to penetrate into the lesion position of the balloon catheter are improved, and at the same time, the blood vessels are less likely to be damaged; the material selected for the metal spring is a metal wire with a high X-ray attenuation coefficient, which can increase the imaging function of the end of the balloon catheter, facilitate the doctor to adjust the position of the end in time according to needs, reduce the surgical operation time, and at the same time ensure the flexibility of the end while providing support for the polymer outer layer to prevent the terminal tube from deforming when encountering resistance or overly tortuous blood vessels, thereby reducing the deliverability, positioning ability and withdrawal performance of the balloon catheter.

[0070] The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions or substitutions can still be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. A balloon catheter, characterized in that, it comprises a distal tube, an inner lumen tube, a balloon body and an outer tube, wherein: The distal tube comprises a distal end portion and a connecting portion which are axially connected. The distal end portion is located at the distal end of the connecting portion, and the outer diameter of the distal end of the distal end portion is smaller than the outer diameter of the connecting portion. The distal tube comprises a housing and a support layer. The housing extends at least from the distal end portion to the connecting portion. The support layer is at least partially located at the connecting portion and is located inside the housing; the distal end portion of the distal tube is a single-layer structure only comprising the housing; the housing at the distal end portion has a tapered structure with an outer diameter gradually increasing from the distal end to the proximal end at the distal end portion; The inner lumen tube penetrates through the balloon body and is connected to the proximal end of the distal tube; The distal end of the balloon body is fixed at the connection between the inner lumen tube and the distal tube, on the distal tube or on the inner lumen tube, and the proximal end of the balloon body is connected to the distal end of the outer tube.

2. The balloon catheter according to claim 1, characterized in that, the outer diameter of the distal end of the distal end portion of the distal tube is 0.0155 inches - 0.018 inches, the inner diameter of the distal end of the distal end portion of the distal tube is 0.0150 inches - 0.0157 inches, and the length of the distal end portion of the distal tube is 0.2 mm - 1.5 mm.

3. The balloon catheter according to claim 1, characterized in that, the distal tube further comprises a proximal end portion located at the proximal end of the connecting portion. The housing extends from the distal end portion of the distal tube to the proximal end portion, and the distal end of the inner lumen tube extends into the inside of the housing at the proximal end portion of the distal tube.

4. The balloon catheter according to claim 1, characterized in that, the support layer comprises a metal spring or a metal braided structure.

5. The balloon catheter according to claim 4, characterized in that, the metal spring or the metal braided structure comprises metal wires, and the material of the metal wires comprises one or more of platinum, tungsten, tantalum, platinum-iridium alloy, platinum-nickel alloy, platinum-tungsten alloy, platinum-tantalum alloy or gold.

6. The balloon catheter according to claim 5, characterized in that, the size of the metal wires is 0.00075 inches - 0.003 inches.

7. The balloon catheter according to claim 4, characterized in that, the outer diameter of the distal end of the metal spring or the metal braided structure is smaller than or equal to the outer diameter of the proximal end of the metal spring or the metal braided structure.

8. A method for manufacturing a balloon catheter according to any one of claims 1 - 7, characterized in that, it comprises the following steps: providing an operating wire and manufacturing the support layer around the operating wire; providing the inner lumen tube, passing the operating wire through the support layer and the inner lumen tube, and making the proximal end of the support layer abut against the distal end of the inner lumen tube; slipping a housing over the outer periphery of the distal end of the support layer and the inner lumen tube, and making the housing at least extend to cover the support layer, including making the housing extend beyond the distal end of the support layer, so as to at least form the connecting portion of the distal tube at the position corresponding to the support layer, and forming the distal end portion of the distal tube at the position corresponding to only the housing; Provide the balloon body and the outer tube, fix the distal end of the balloon body at the connection of the inner cavity tube and the end tube, on the end tube or on the inner cavity tube, and connect the proximal end of the balloon body to the distal end of the outer tube; Connect the support layer, the inner cavity tube, the housing, the balloon body and the outer tube into one body by laser welding.

9. The method for preparing a balloon catheter according to claim 8, characterized in that, The distal end of the operating wire has a tapered structure with an outer diameter gradually increasing from the distal end to the proximal end.

10. The method for preparing a balloon catheter according to claim 8, characterized in that, The making the housing extend to cover the support layer includes: Extend the distal end of the inner cavity tube into the proximal end of the inside of the housing to form the proximal end portion of the end tube corresponding to the distal end of the inner cavity tube.

11. The method for preparing a balloon catheter according to claim 8, characterized in that, The making the support layer around the operating wire includes: Provide at least one metal wire, helically wind the metal wire around the distal end of the operating wire to form a metal spring; or Weave the metal wire at the distal end of the operating wire to form a metal braided structure.

12. The method for preparing a balloon catheter according to claim 11, characterized in that, The metal wire includes one or more of platinum, tungsten, tantalum, platinum-iridium alloy, platinum-nickel alloy, platinum-tungsten alloy, tungsten-tantalum alloy or gold.

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