Restraint for wrapping a balloon and method of making same, balloon catheter

Abstract

The application relates to the technical field of balloons, and particularly discloses a restraint for wrapping a balloon, a preparation method of the restraint and a balloon catheter. The restraint comprises a plurality of axial restraint rods and a plurality of radial restraint rods, the plurality of axial restraint rods are arranged at intervals in a circumferential direction, at least one radial restraint rod comprises two root sections and an intermediate section arranged between the two root sections, the two root sections are fixedly connected with two adjacent axial restraint rods respectively, and the shapes of the cross sections of the root sections and the intermediate section are different. The root sections and the intermediate section of at least one radial restraint rod are arranged in different shapes to adapt to different characteristics of the root sections and the intermediate section, so that the distribution of stress and strain on the radial restraint rod is more uniform, the stress concentration is improved, and the risk of fracture of the radial restraint rod can be effectively reduced.

Description

Technical Field

[0001] This application relates to the field of balloon technology, and in particular to a restraint for wrapping a balloon and its preparation method, as well as a balloon catheter. Background Technology

[0002] Balloon angioplasty (angioplasty) is a common treatment method primarily used to widen and reconstruct narrowed areas of blood vessels or non-vascular passages. The balloon inflates at the narrowed site to apply radial pressure to the inner wall of the vessel, thereby widening the narrowed area and allowing for better blood flow.

[0003] To reduce damage to the blood vessel wall when the balloon is inflated, current technology allows for the attachment of a nickel-titanium mesh to the balloon surface as a restraint. When the balloon inflates, the nickel-titanium mesh forms a occipital region on the balloon surface, ensuring that the lesions in the blood vessel wall are subjected to uniform compressive force.

[0004] However, when the existing nickel-titanium mesh is compressed by the balloon expansion, the radial rod that is the main actuator is prone to stress concentration. After repeated expansion and contraction, it is prone to breakage, which in turn brings safety hazards. Summary of the Invention

[0005] Therefore, it is necessary to provide a constraint for wrapping a balloon and its preparation method, as well as a balloon catheter, to address the above problems.

[0006] According to a first aspect of the embodiments of this application, a constraint member for wrapping a balloon is provided, the constraint member comprising:

[0007] A plurality of axial constraint rods, wherein the plurality of axial constraint rods are spaced apart along the circumferential direction;

[0008] A plurality of radial constraint rods, at least one radial constraint rod comprising two root segments and an intermediate segment disposed between the two root segments, wherein the two root segments are respectively fixedly connected to two adjacent axial constraint rods, and the root segments and the intermediate segment have different cross-sectional shapes.

[0009] In one embodiment, the shape of the cross-section of the intermediate segment includes a generally circular shape, and / or the shape of the cross-section of the root segment includes a rectangle and has a first chamfer angle.

[0010] In one embodiment, the constraint further includes a transition section connecting the root section and the intermediate section, the shape of the cross-section of the transition section being different from at least one of the cross-sections of the root section and the intermediate section.

[0011] In one embodiment, the cross-sectional shape of the transition segment includes a rectangle and has a second chamfer angle, and the cross-sectional shape of the root segment includes a rectangle and has a first chamfer angle, wherein the second chamfer angle is greater than the first chamfer angle.

[0012] In one embodiment, the maximum cross-sectional width of the root segment gradually decreases from the transition segment to the middle segment.

[0013] In one embodiment, the transition section is bent between two adjacent axial constraint bars and is configured to be stretched under external force.

[0014] In one embodiment, the length of the intermediate segment is between 1.25 mm and 1.65 mm, and the length of the root segment is between 0.85 mm and 1.05 mm.

[0015] According to a second aspect of the present application, a balloon catheter is provided, including a balloon, a catheter assembly, and the aforementioned restraint member, wherein the restraint member covers the periphery of the balloon, and the catheter assembly is connected to one end of the balloon.

[0016] According to a second aspect of the embodiments of this application, a method for manufacturing a constraint member is provided, comprising:

[0017] The plurality of axial constraint rods and the plurality of radial constraint rods are obtained by cutting, wherein the cutting includes cutting the root segment and the middle segment into structures with rectangular cross-sectional shapes but different sizes;

[0018] The axial constraint rods and the radial constraint rods are polished. The polishing process includes applying a voltage to both ends of the constraint members so that current flows through the radial constraint rods. The current density is different for different cross-sectional portions of the radial constraint rods, so that the polishing amount is different for portions with different cross-sectional sizes.

[0019] In one embodiment, the step of cutting to obtain a plurality of radial constraint bars further includes cutting the transition segment connecting the root segment and the intermediate segment of the radial constraint bar into a structure with a rectangular cross-sectional shape and a size between that of the intermediate segment and the root segment.

[0020] In one embodiment, in the step of cutting to obtain the plurality of axial constraint rods and the plurality of radial constraint rods, a laser cutting machine is used for cutting, and the laser energy of the laser cutting machine is between 7W and 15W.

[0021] In one embodiment, in the step of cutting to obtain the plurality of axial constraint rods and the plurality of radial constraint rods, the root segment is cut into a first structure with a rectangular cross-section, the transition segment is cut into a second structure with a rectangular cross-section, and the middle segment is cut into a third structure with a square cross-section. The aspect ratio of the rectangle of the first structure is greater than that of the rectangle of the second structure.

[0022] The constraint member for enclosing a balloon provided in this application includes a plurality of axial constraint rods and a plurality of radial constraint rods. The axial constraint rods are spaced apart along the circumferential direction. At least one radial constraint rod includes two root segments and an intermediate segment disposed between the two root segments. The two root segments are fixedly connected to two adjacent axial constraint rods, respectively. The root segments and the intermediate segment have different cross-sectional shapes. That is, this application embodiment sets the root segments and intermediate segments of at least one radial constraint rod into different shapes to accommodate the different characteristics of the root segments and the intermediate segments. This results in a more uniform distribution of stress and strain on the radial constraint rod, improves stress concentration, and effectively reduces the risk of radial constraint rod breakage. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of a constraint element provided in an embodiment of this application;

[0024] Figure 2 This is a partial structural schematic diagram of a constraint element provided in one embodiment of this application;

[0025] Figure 3 A structural schematic diagram of the cross-sections corresponding to each region of the constraint component;

[0026] Figure 4 A schematic diagram of the structure when the uniformly constrained member is stretched open;

[0027] Figure 5 This is a schematic diagram of the structure when the gradient constraint is stretched open.

[0028] Figure 6 This is a schematic diagram of the structure of a balloon catheter provided in one embodiment of this application;

[0029] Figure 7 This is a flowchart illustrating a method for preparing a constraint element according to an embodiment of this application.

[0030] Explanation of reference numerals in the attached figures:

[0031] 100. Constraint; 110. Axial constraint bar; 120. Radial constraint bar; 121. Root section; 122. Transition section; 123. Intermediate section; 300. Conduit assembly. Detailed Implementation

[0032] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0033] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0034] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0036] Balloon angioplasty (angioplasty) is a common treatment method primarily used to widen and reconstruct narrowed areas of blood vessels or non-vascular passages. The balloon inflates at the narrowed site to apply radial pressure to the inner wall of the vessel, thereby widening the narrowed area and allowing for better blood flow.

[0037] Uneven balloon inflation is often caused by the uneven nature of lesions within blood vessels. Angioplasty balloons are typically non-flexible or semi-flexible, and when a semi-flexible balloon is inflated against an eccentric lesion, it inflates along the "path of least resistance," increasing its diameter most significantly in areas with less disease, thus increasing the risk of damage to those areas. To reduce damage to the vessel wall during balloon inflation, a nickel-titanium mesh can be attached to the balloon surface as a restraint. When the balloon inflates, the nickel-titanium mesh, clamped onto the balloon surface, forms a occipital region, distributing the compressive force evenly across the lesion tissue of the vessel wall.

[0038] However, existing nickel-titanium mesh is prone to breakage after repeated expansion and contraction when subjected to balloon expansion and compression, posing a safety hazard. The inventors of this application, through simulation analysis, discovered that nickel-titanium mesh breakage primarily occurs on the radial rods. During use, different locations on the radial rods experience varying stresses. This uneven stress distribution leads to various problems with the radial rods. For example, the middle section of the radial rod is susceptible to torsional forces leading to breakage; the root of the radial rod experiences greater bending forces, also increasing the risk of breakage; and the connection between the middle and root sections is prone to deformation and breakage under tensile force. In other words, the radial rods, which are the primary moving parts, are prone to stress concentration, making them susceptible to breakage after repeated expansion and contraction, thus creating a safety hazard.

[0039] To address the aforementioned issues, embodiments of this application provide a constraint for wrapping a balloon, a method for preparing the same, and a balloon catheter.

[0040] In one embodiment, a constraint is provided for enclosing the balloon.

[0041] Reference Figure 1 and Figure 2 The constraint member 100 provided in this embodiment includes a plurality of axial constraint rods 110 and a plurality of radial constraint rods 120. The plurality of axial constraint rods 110 are arranged at intervals along the circumferential direction; at least one radial constraint rod 120 includes two root segments 121 and an intermediate segment 123 disposed between the two root segments 121, wherein the two root segments 121 are fixedly connected to two adjacent axial constraint rods 110 respectively, and the cross-sectional shapes of the root segments 121 and the intermediate segment 123 are different.

[0042] In this embodiment, the root segment 121 and the middle segment 123 of at least one radial constraint rod 120 are set with different shapes to adapt to the different characteristics of the root segment 121 and the middle segment 123, so that the stress and strain are more evenly distributed on the radial constraint rod 120, improving the stress concentration situation and effectively reducing the risk of radial constraint rod 120 fracture.

[0043] In this embodiment, each axial constraint rod 110 extends axially and is spaced apart along the circumferential direction. Each radial constraint rod 120 is connected between two adjacent axial constraint rods 110. The radial constraint rods 120 and the axial constraint rods 110 cooperate to form a mesh-like constraint member 100. When the constraint member 100 is wrapped around the balloon, the constraint member 100 can expand or contract with the state of the balloon, thereby limiting the size and shape of the balloon's expansion. That is, the constraint member 100 can expand axially and radially in coordination with the balloon's expansion process, and can hold the balloon in the desired position during the balloon's expansion.

[0044] Among them, reference Figure 2 At least one radial constraint rod 120 includes two root segments 121 and an intermediate segment 123 disposed between the two root segments 121. The two root segments 121 are fixedly connected to two adjacent axial constraint rods 110 in the circumferential direction, and the cross-sectional shapes of the root segments 121 and the intermediate segment 123 are different. Specifically, the cross-sectional shapes of the root segments 121 and the intermediate segment 123 on some radial constraint rods 120 may be different, or the cross-sectional shapes of the root segments 121 and the intermediate segment 123 on all radial constraint rods 120 may be different, depending on actual needs.

[0045] Because the root segment 121 and the intermediate segment 123 are located at different positions, the risk types corresponding to the root segment 121 and the intermediate segment 123 are also different during the repeated extension and contraction of the radial constraint rod 120. For example, the intermediate segment 123 is more prone to deformation, while the stress in the root segment 121 is more concentrated, making it more susceptible to torsion and fracture. Therefore, the structural design requirements for the root segment 121 and the intermediate segment 123 are also different. For example, the root segment 121 needs higher mechanical strength and torsional resistance, while the intermediate segment 123 needs good deformation performance and the ability to withstand the impact of multiple deformations. Based on the above considerations, in this embodiment, according to the different functional requirements of the root segment 121 and the intermediate segment 123, the root segment 121 and the intermediate segment 123 are set with different shapes, that is, the cross-sectional shapes of the root segment 121 and the intermediate segment 123 are different. This satisfies the different requirements of the root segment 121 and the intermediate segment 123, thereby reducing the risk of fracture of the radial constraint rod 120.

[0046] In one embodiment, reference Figure 3The cross-sectional shape of the intermediate section 123 can be approximately circular. "Approximately circular" means it is circular overall, but slight deviations are permissible; it does not have to be an absolutely perfect circle. The width of the intermediate section 123 can be between 0.06mm and 0.12mm, meaning the diameter of the circular cross-section can be between 0.06mm and 0.12mm, specifically 0.06mm, 0.08mm, 0.1mm, or 0.12mm, etc., depending on actual requirements.

[0047] Setting the shape of the middle section 123 to be circular can, to a certain extent, ensure that the middle section 123 can maintain good deformation performance even when subjected to shear force, and can withstand more deformation impacts without breaking.

[0048] In one embodiment, reference Figure 3 The cross-sectional shape of the root segment 121 may be rectangular and have a first chamfer angle. Unlike the intermediate segment 123 with a circular cross-sectional shape, the cross-sectional shape of the root segment 121 is rectangular and has a chamfer. The chamfer makes it less likely for the root segment 121 to wear or damage the balloon after contacting it. In this application, the degree of its chamfer is defined as the first chamfer angle.

[0049] Setting the cross-sectional shape of the root segment 121 to be rectangular can, on the one hand, give the root segment 121 higher mechanical strength, and on the other hand, ensure that it is not easily twisted and broken. Furthermore, stress can be distributed on the root segment 121, improving the stress concentration problem at the connection between the root segment 121 and the axial constraint rod 110.

[0050] In one embodiment, reference Figure 2 and Figure 3 The constraint member 100 also includes a transition section 122, which connects the root section 121 and the intermediate section 123. The shape of the cross-section of the transition section 122 is different from at least one of the cross-sections of the root section 121 and the intermediate section 123. That is, the shape of the cross-section of the transition section 122 may be different from the cross-section shape of the root section 121 and the same as the cross-section shape of the intermediate section 123; it may also be different from the cross-section shape of the intermediate section 123 and the same as the cross-section shape of the root section 121; or it may be different from the cross-section shapes of both the root section 121 and the intermediate section 123.

[0051] In practical applications, the transition section 122 can be bent between two adjacent axial constraint bars 110 and is configured to be stretched under external force. That is, when the constraint member 100 is in the retracted state, the distance between the two adjacent axial constraint bars 110 is shortened, and the transition section 122 is bent between the two adjacent axial constraint bars 110; when the constraint member 100 is in the extended state, the distance between the two adjacent axial constraint bars 110 is increased, and the transition section 122 can be stretched open.

[0052] In one embodiment, reference Figure 3 The cross-sectional shape of the transition segment 122 may be rectangular and have a second chamfer angle, which is greater than the first chamfer angle. That is, in practical applications, the cross-section of the root segment 121 is a rectangle with chamfers, while the cross-section of the transition segment 122 is a rectangle with a larger chamfer. Setting the cross-section of the transition segment 122 as a rectangle with chamfers can, on the one hand, give the transition segment 122 anti-torsion performance, and on the other hand, the chamfer design can enhance the elasticity of the transition segment 122 and make it less likely to wear or damage the balloon when in contact with it.

[0053] In one embodiment, the maximum cross-sectional width gradually decreases from the root segment 121 to the transition segment 122 and the intermediate segment 123. That is, the maximum cross-sectional width of the root segment 121 is the largest, the maximum cross-sectional width of the transition segment 122 is the second largest, and the maximum cross-sectional width of the intermediate segment 123 is the smallest. This can simultaneously meet the mechanical strength requirements of the root segment 121 and the requirements for torsional resistance and deformation resistance of the intermediate segment 123 and the transition segment 122.

[0054] In one embodiment, the length of the intermediate segment 123 is between 1.25 mm and 1.65 mm, and the length of the root segment 121 is between 0.85 mm and 1.05 mm. Specifically, the intermediate segment 123 can be 1.25 mm, 1.4 mm, or 1.65 mm, etc., and the root segment 121 can be 0.85 mm, 0.96 mm, or 1.05 mm, etc. The specific length of each segment can be set according to actual needs and is not specifically limited here.

[0055] In addition, the width of the axial constraint rod 110 is between 0.1mm and 0.15mm, specifically 0.1mm, 0.12mm, 0.14mm, or 0.15mm, etc.

[0056] In this embodiment, the material of the constraint member 100 may include nickel-titanium alloy, copper-nickel alloy, etc.

[0057] In a specific example, the cross-section of the radial constraint rod 120 in the constraint member, from the middle section 123 to the root section 121, has a gradient design. That is, the cross-section gradually changes from a circle in the middle section 123 to a chamfered rectangle in the root section 121, and the cross-section of the transition section 122 between the middle section 123 and the root section 121 is a rectangle with a larger chamfer. In contrast, in the constraint member 100 of the conventional technology, the cross-sectional shape of the radial constraint rod 120 is the same at all points.

[0058] The constraint member 100 (gradual constraint member 100) in the above specific example and the constraint rod (uniform constraint member 100) in the conventional technology were respectively wrapped around the periphery of the balloon and tested.

[0059] Depend on Figure 4 It can be seen that during the balloon inflation process, the uniform constraint rods are gradually expanded. During this process, the arc-shaped radial constraint rod 120 maintains its arc shape, even after being fully expanded. This results in an excessively large opening angle (>180°) for the radial constraint rod 120, leading to stress concentration at the connection between the radial constraint rod 120 and the axial constraint rod 110. Figure 4 The left-middle image shows the state when the uniformly constrained rod is stretched by 1 / 2. Figure 4 The middle right figure shows the state when the uniform constraint rod is fully stretched.

[0060] And by Figure 5 It can be seen that during the opening process of the gradual constraint rod, the radial constraint rod 120 is gradually straightened, and after full opening, the arc shape on the radial constraint rod 120 is completely straightened. The opening angle of the radial constraint rod 120 is less than 180°. During the opening process, the stress on the radial constraint rod 120 is gradually released, alleviating the stress concentration problem at the connection between the radial constraint rod 120 and the axial constraint rod 110. Figure 5 The left-middle image shows the state when the gradient constraint rod is stretched to 1 / 2. Figure 5 The middle right figure shows the state when the gradient constraint rod is fully extended.

[0061] Experiments show that the fatigue life of a traditional uniform constraint bar is 8-10 cycles, while the fatigue life of the gradient constraint 100 provided in this embodiment is 15-18 cycles. Therefore, it can be seen that the gradient constraint 100 provided in this embodiment has a longer fatigue life compared to a traditional uniform constraint bar.

[0062] In one embodiment, refer to Figure 6A balloon catheter is provided, comprising a balloon, a catheter assembly 300, and the aforementioned restraint member 100. The restraint member 100 covers the periphery of the balloon, and the catheter assembly 300 is connected to one end of the balloon. The catheter assembly 300 allows control of the balloon's entry into or exit from the human body. When the balloon is inflated, the restraint member 100 expands accordingly, thus restraining the balloon.

[0063] The radial constraint rod 120, as part of the constraint member 100, is typically small. Conventional manufacturing methods make it difficult to design various shapes on the radial constraint rod 120, and complex processing techniques can lead to reduced yield and decreased reliability. Therefore, this application also provides a method for manufacturing the constraint member 100. This method can produce the constraint member 100 provided in the aforementioned embodiments without complex processes and with a high yield.

[0064] The method for preparing the constraint member 100 provided in this embodiment includes the following steps:

[0065] Step S200: Cutting to obtain several axial constraint rods 110 and several radial constraint rods 120. The cutting includes cutting the root section 121 and the middle section 123 into structures with rectangular cross-sectional shapes and different sizes.

[0066] Specifically, a femtosecond laser cutting machine can be used to cut the nickel-titanium tubing to obtain several axial constraint rods 110 spaced apart along the circumference and several radial constraint rods 120 connecting two adjacent axial constraint rods 110. During the cutting process, the root section 121 and the middle section 123 of the radial constraint rods 120 can be cut into structures with rectangular cross-sectional shapes but different dimensions.

[0067] In this case, the cross-sectional dimension of the root segment 121 obtained by cutting can be larger than the cross-sectional dimension of the middle segment 123.

[0068] In one embodiment, during the process of cutting to obtain a plurality of radial constraint rods 120, the transition segment 122 connecting the root segment 121 and the intermediate segment 123 can also be cut into a structure with a rectangular cross-sectional shape and a size between that of the intermediate segment 123 and the root segment 121. That is, the cross-sectional size of the root segment 121 is larger than that of the transition segment 122, and the cross-sectional size of the transition segment 122 is larger than that of the intermediate segment 123.

[0069] The root segment 121 can be cut into a first structure with a rectangular cross-section, the transition segment 122 can be cut into a second structure with a rectangular cross-section, and the middle segment 123 can be cut into a third structure with a square cross-section. The aspect ratio of the rectangle in the first structure is greater than that of the rectangle in the second structure.

[0070] Specifically, the first structure and the second structure can have the same height, and the width of the first structure can be greater than the width of the second structure.

[0071] Furthermore, the heights of the first, second, and third structures can all be the same, while the widths of the first, second, and third structures gradually decrease.

[0072] In step S200, the laser energy of the laser cutting machine can be between 7W and 15W. The laser frequency can be 600KHz.

[0073] Step S400: Polish each axial constraint rod 110 and each radial constraint rod 120. The polishing process includes applying voltage to both ends of the constraint member 100 so that current passes through the radial constraint rod 120. The current density of different cross-sectional parts of the radial constraint rod 120 is different so that the polishing amount of different cross-sectional parts is different.

[0074] Specifically, in the electrochemical polishing process, the current density is lower in areas with larger cross-sectional dimensions and higher in areas with smaller cross-sectional dimensions. Therefore, areas with smaller cross-sectional dimensions can achieve a larger polishing amount, while areas with larger cross-sectional dimensions can achieve a smaller polishing amount.

[0075] In this embodiment, the cross-sectional dimension of the root segment 121 is larger than that of the transition segment 122, and the cross-sectional dimension of the transition segment 122 is larger than that of the middle segment 123. Therefore, the polishing amount of the middle segment 123 is the largest, the polishing amount of the transition segment 122 is the second largest, and the polishing amount of the root segment 121 is the smallest. After polishing, the cross-section of the middle segment 123 can be made into a generally circular shape, the cross-section of the root segment 121 can be made into a rectangle with chamfers, and the cross-section of the transition segment 122 can be made into a rectangle with larger chamfers, approximately elliptical.

[0076] In step S400, the electrochemical polishing solution used can be an acid-alcohol system, the polishing voltage can be 40V, the current can be 2.5A, and the polishing can last for 50s.

[0077] Furthermore, after polishing, the constraint 100 can be placed in an air-circulating box furnace for heat setting. In a specific example, the temperature of the air-circulating box furnace can be set to 480℃, the heat setting time can be set to 5 minutes, and the resulting mesh phase transition temperature Af can be 26±5℃. After the heat setting is completed, the constraint 100 can be connected to the balloon.

[0078] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0079] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A restraint for enclosing a balloon, characterized in that, The constraint includes: A plurality of axial constraint rods, wherein the plurality of axial constraint rods are spaced apart along the circumferential direction; A plurality of radial constraint rods, at least one radial constraint rod comprising two root segments and an intermediate segment disposed between the two root segments, wherein the two root segments are respectively fixedly connected to two adjacent axial constraint rods; The cross-sectional shape of the intermediate segment is generally circular, the cross-sectional shape of the root segment is rectangular, and the maximum cross-sectional width of the root segment gradually decreases from the intermediate segment.

2. The constraint member according to claim 1, characterized in that, The cross-section of the root segment has a first reciprocal angle.

3. The constraint member according to claim 1, characterized in that, The constraint further includes a transition section connecting the root section and the intermediate section, the shape of the cross-section of the transition section being different from at least one of the cross-sections of the root section and the intermediate section.

4. The constraint member according to claim 3, characterized in that, The cross-section of the transition section has a rectangular shape and a second chamfer angle, and the cross-section of the root section has a first chamfer angle, wherein the second chamfer angle is greater than the first chamfer angle.

5. The constraint member according to claim 3, characterized in that, The maximum cross-sectional width gradually decreases from the root segment to the transition segment and the middle segment.

6. The constraint member according to claim 3, characterized in that, The transition section bends between two adjacent axial constraint bars and is configured to be stretched under external force.

7. The constraint member according to claim 1, characterized in that, The length of the middle section is between 1.25 mm and 1.65 mm, and the length of the root section is between 0.85 mm and 1.05 mm.

8. A balloon catheter, characterized in that, The device includes a balloon, a catheter assembly, and a restraint as described in any one of claims 1-7, the restraint covering the periphery of the balloon, and the catheter assembly connected to one end of the balloon.

9. A method for manufacturing a constraint member as described in any one of claims 1-7, characterized in that, The preparation method includes: The plurality of axial constraint rods and the plurality of radial constraint rods are obtained by cutting, wherein the cutting includes cutting the root segment and the middle segment into structures with rectangular cross-sectional shapes but different sizes; The axial constraint rods and the radial constraint rods are polished. The polishing process includes applying a voltage to both ends of the constraint members so that current flows through the radial constraint rods. The current density is different for different cross-sectional portions of the radial constraint rods, so that the polishing amount is different for portions with different cross-sectional sizes.

10. The preparation method according to claim 9, characterized in that, The step of cutting to obtain a plurality of radial constraint rods further includes cutting the transition segment connecting the root segment and the intermediate segment of the radial constraint rod into a structure with a rectangular cross-sectional shape and a size between that of the intermediate segment and the root segment.

11. The preparation method according to any one of claims 9-10, characterized in that, In the step of cutting to obtain the plurality of axial constraint rods and the plurality of radial constraint rods, a laser cutting machine is used for cutting, and the laser energy of the laser cutting machine is between 7W and 15W.

12. The preparation method according to claim 10, characterized in that, In the step of cutting to obtain the plurality of axial constraint rods and the plurality of radial constraint rods, the root segment is cut into a first structure with a rectangular cross-section, the transition segment is cut into a second structure with a rectangular cross-section, and the middle segment is cut into a third structure with a square cross-section. The aspect ratio of the rectangle of the first structure is greater than that of the rectangle of the second structure.

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