Fast exchange balloon dilatation catheter and method of making balloon dilatation catheter

Abstract

This invention provides a quick-connect balloon dilation catheter and a method for preparing the balloon dilation catheter. The quick-connect balloon dilation catheter includes a catheter seat, an outer tube connected to the catheter seat, and a balloon connected to the distal end of the outer tube. The outer tube has a metal tube body extending from the proximal end to the distal end, the metal tube body having a non-cutting segment at the proximal end and a cutting segment connected to the distal end of the non-cutting segment. The outer tube also has a polymer inner liner covering the inside of the cutting segment and a polymer sheath covering the outside of the cutting segment, such that the outer tube is integrally formed as a composite tube segment with a metal tube segment at the proximal end and a composite tube segment connected to the distal end of the metal tube segment, the composite tube segment having a quick-connect port penetrating both the inside and outside. This design improves the catheter's delivery and positioning accuracy.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a quick-connect balloon dilation catheter and a method for preparing the balloon dilation catheter. Background Technology

[0002] Intracranial atherosclerotic stenosity (ICAS), also known as intracranial atherosclerotic disease, is a common cause of ischemic stroke. Stroke patients with ICAS experience more severe symptoms, longer hospital stays, and the recurrence rate of stroke increases with the degree of vascular stenosis, seriously endangering national health and hindering social and economic development.

[0003] Currently, the main methods for prevention and treatment of acute myocardial infarction (ICAS) include drug therapy and endovascular interventional therapy. However, studies have found that even with aggressive drug therapy, the one-year stroke recurrence rate for symptomatic ICAS patients remains as high as 20%. Therefore, endovascular interventional therapy, as an effective alternative treatment, plays a significant role in patients with severe stenosis, drug-resistant ICAS, and hemodynamic instability. Balloon catheters are currently a common interventional device, and they can be classified according to different product characteristics. Structurally, they can be divided into coaxial structures and quick-exchange (hereinafter referred to as "quick-exchange") structures. In the design of quick-exchange balloon dilation catheters, the inner and outer tubes are coaxially set only in the distal 25cm length. Both are currently generally set as single-layer polymer extrusion tubes, resulting in poor pushing performance and limited adjustment space at the design end, making it impossible to design specifically for particular indications.

[0004] Therefore, it is necessary to provide an improved quick-exchange balloon dilation catheter and its preparation method to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a quick-connect balloon dilation catheter and its preparation method to improve the catheter's delivery and positioning.

[0006] One embodiment of the present invention provides a quick-connect balloon dilation catheter, which includes a catheter seat, an outer tube connected to the catheter seat, and a balloon connected to the distal end of the outer tube. The outer tube has a metal tube body extending from the proximal end to the distal end. The metal tube body has a non-cutting segment located at the proximal end and a cutting segment connected to the distal end of the non-cutting segment. The outer tube also has a polymer inner liner covering the inner side of the cutting segment and a polymer sheath covering the outer side of the cutting segment, such that the outer tube is integrally formed as a composite tube segment with a metal tube segment located at the proximal end and a composite tube segment connected to the distal end of the metal tube segment. The composite tube segment is provided with a quick-connect port that runs through both the inner and outer sides.

[0007] In one embodiment of the present invention, the length of the metal pipe segment is twice the length of the composite pipe segment, the length of the metal pipe segment is 1000-1200mm, and the length of the composite pipe segment is 500-600mm.

[0008] In one embodiment of the present invention, the metal tube body is made of 340 stainless steel, or 316 stainless steel or nickel-titanium alloy, the inner lining is made of PTFE material, and the sleeve is made of nylon-like polymer material with heat shrink properties.

[0009] In one embodiment of the present invention, the cutting segment includes a transition segment, a first cutting segment, a second cutting segment and a third cutting segment arranged sequentially from the proximal end to the distal end, wherein the stiffness of the first cutting segment, the second cutting segment and the third cutting segment decreases sequentially.

[0010] As one embodiment of the present invention, the stiffness reduction slope of the first cutting section 231 is 0.8 to 1.0 gf / mm, the stiffness reduction slope of the second cutting section 232 is 2.0 to 2.2 gf / mm, and the stiffness reduction slope of the third cutting section 233 is 0.1 to 0.2 gf / mm.

[0011] In one embodiment of the present invention, the length of the first cutting section is 110-130mm, the length of the second cutting section is 150-170mm, the length of the third cutting section is 220-240mm, and the length of the transition section is 20-30mm.

[0012] In one embodiment of the present invention, the sleeve is provided with a first pipe section, a second pipe section and a third pipe section. The first pipe section covers the transition section and the first cutting section, the second pipe section covers the second cutting section, and the third pipe section covers the third cutting section. The first pipe section is made of Pebax 7033 material, the second pipe section is made of Pebax 6333 material, and the third pipe section is made of Pebax 5533 material.

[0013] In one embodiment of the present invention, the quick-intercept is located 240-280 mm from the distal end of the quick-intercept balloon dilation catheter.

[0014] The present invention also provides a method for preparing a balloon dilation catheter, comprising:

[0015] A metal tube body is provided, the metal tube body having a non-cut section located at a proximal end and a cut section connected to the distal end of the non-cut section;

[0016] An expandable mandrel that can be expanded by heating is provided, and a polymer inner liner is placed around the expandable mandrel;

[0017] An expansion mandrel with an inner lining is inserted into the metal tube body, so that the inner lining is located inside the cut section.

[0018] The expansion mandrel is heated to expand it, thereby fixing the inner liner to the inside of the cut section;

[0019] The polymer sleeve is fitted onto the outside of the cutting section to cover the outer wall of the cutting section, so that the cutting section of the metal pipe body forms a composite pipe section.

[0020] Remove the expansion mandrel.

[0021] In one embodiment of the present invention, the length of the inner lining layer is greater than the length of the cut section. When the expansion mandrel is placed inside the metal tube body, both ends of the expansion mandrel extend out of the cut section, and the extension length of the expansion mandrel at the far end of the cut section is not less than 10cm.

[0022] In one embodiment of the present invention, the metal tube body is made of one of 340 stainless steel, 316 stainless steel or nickel-titanium alloy, the inner lining is made of PTFE material, the sleeve is made of nylon-like polymer material with heat shrink properties, and the expansion mandrel is made of PTFE or FEP material.

[0023] As one embodiment of the present invention, "heating the expansion mandrel" specifically includes:

[0024] First, the expansion mandrel is pre-expanded and heated so that after the expansion mandrel is pre-expanded, the inner lining layer contacts the inner wall of the cut section of the metal tube body, so as to achieve relative fixation of the expansion mandrel, the inner lining layer and the metal tube body;

[0025] Then, a laminating machine is used to heat and expand the inner lining layer so that it is firmly fixed inside the metal tube body.

[0026] In one embodiment of the present invention, the expansion mandrel is made of FEP material. During pre-expansion heating, a hot air blower is used, the heating temperature is 180-200°C, and the heating time is 1-2 minutes. When reheating using a laminating machine, the heating temperature is 180-200°C, and the moving speed is 3-5 mm / s.

[0027] In one embodiment of the present invention, the polymer sleeve is fitted onto the outside of the cut section of the metal tube body after "pre-expansion heating of the expansion mandrel" and before "heating expansion using a coating machine";

[0028] Alternatively, after the polymer sleeve is heated and expanded using a coating machine, it is fitted onto the outside of the cut section of the metal tube body. In this case, the preparation method further includes: heating again using a coating machine to heat-shrink and fix the polymer sleeve to the outside of the cut section.

[0029] In one embodiment of the present invention, the cutting segment includes a transition segment, a first cutting segment, a second cutting segment, and a third cutting segment arranged sequentially from the proximal end to the distal end, wherein the stiffness of the first cutting segment, the second cutting segment, and the third cutting segment decreases sequentially; the polymer sleeve is provided with a first tube segment, a second tube segment, and a third tube segment, wherein the first tube segment covers the transition segment and the first cutting segment, the second tube segment covers the second cutting segment, and the third tube segment covers the third cutting segment; the first tube segment is made of Pebax 7033 material, the second tube segment is made of Pebax 6333 material, and the third tube segment is made of Pebax 5533 material.

[0030] In one embodiment of the present invention, the length of the non-cutting segment is twice the length of the cutting segment, the length of the non-cutting segment is 1000-1200mm, the length of the cutting segment is 500-600mm; the length of the first cutting segment is 110-130mm, the length of the second cutting segment is 150-170mm, the length of the third cutting segment is 220-240mm, and the length of the transition segment is 10-30mm.

[0031] As one embodiment of the present invention, the preparation method further includes:

[0032] After the expansion mandrel is removed, a quick joint is formed in the composite pipe section;

[0033] After forming the quick-joint, an inner tube is installed inside the metal tube body through the quick-joint, and the two are welded together at the quick-joint position.

[0034] The quick-connect balloon dilation catheter provided by this invention has an outer tube with an integrally connected metal tube body, which ensures the overall delivery performance of the catheter. In addition, the proximal end of the metal tube body is set as a non-cutting segment and the distal end as a cutting segment, and a polymer inner and outer layer structure is set on the inner and outer sides of the distal end. This ensures the delivery performance while meeting the requirement of distal flexibility, allowing the catheter to move smoothly in complex and tortuous blood vessels. The overall catheter resistance, flexibility and tracking performance are improved, thereby improving the permeability and positioning accuracy. At the same time, the polymer inner and outer layer structure can also ensure the pressure resistance of the distal end of the catheter.

[0035] Furthermore, in the preparation method of the balloon dilation catheter of the present invention, by using an expansion mandrel for the installation and fixation of the inner liner, the design flexibility can be greatly increased, the adaptability of raw materials and design flexibility can be improved, and the outer diameter of the catheter can be reduced, thereby improving the catheter's permeability; at the same time, the process is simplified, the use of auxiliary consumables is reduced, and the production cost is lowered. Attached Figure Description

[0036] Figure 1This is a schematic diagram of a quick-exchange balloon dilation catheter according to an embodiment of the present invention;

[0037] Figure 2 for Figure 1 The diagram shows the structure of the outer tube of the balloon dilation catheter.

[0038] Figure 3 for Figure 2 A schematic diagram of the structure of the metal tube body in the outer tube is shown. Detailed Implementation

[0039] The following detailed description incorporates the accompanying drawings, which form part of this specification. The illustrative embodiments mentioned in the specification and drawings are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art will understand, based on the teachings of this application, that many other embodiments can be employed and various changes can be made to the described embodiments without departing from the spirit and scope of the invention. It should be understood that the various aspects of this application illustrated herein can be arranged, substituted, combined, separated, and designed in many different configurations, all of which are within the scope of this application.

[0040] The terms used to describe position and direction in this invention are all based on the operator of the surgical instruments during the procedure, with the end closer to the operator being the proximal end and the end farther from the operator being the distal end.

[0041] Please see Figures 1 to 3 As shown, the present invention provides a quick-exchange balloon dilation catheter 100, which is mainly used in a catheter seat 1, an outer tube 2 connected to the catheter seat 1, and a balloon 3 connected to the distal end of the outer tube 2.

[0042] The outer tube 2 has a metal tube body 21 extending from the proximal end to the distal end. The metal tube body 21 has a non-cut section 22 located at the proximal end and a cut section 23 connected to the distal end of the non-cut section 22. The outer tube 2 also has a polymer inner liner 24 covering the inside of the cut section 23 and a polymer sleeve 25 covering the outside of the cut section 23; thus, the outer tube 2 can be integrally formed as a composite tube section having a metal tube section located at the proximal end and a composite tube section connected to the distal end of the metal tube section, the composite tube section having a quick-connect joint 20 that runs through both the inside and outside.

[0043] The aforementioned quick-connect balloon dilation catheter 100 of the present invention has its outer tube 2 configured as having an integrally connected metal tube body 21, thereby ensuring the overall pushing performance of the catheter through the metal tube body 21; in addition, the proximal end of the metal tube body 21 is configured as a non-cutting segment 22 and the distal end as a cutting segment 23, and a polymer inner and outer layer structure is provided on the inner and outer sides of the distal end, thereby ensuring the need for distal flexibility while ensuring pushing performance, allowing the catheter to move smoothly in complex and tortuous blood vessels, improving the overall resistance to bending, flexibility and tracking performance of the catheter, thereby improving the permeability and positioning accuracy; at the same time, the polymer inner and outer layer structure can also ensure the pressure resistance of the distal end.

[0044] In one embodiment of the present invention, the conduit seat 1 has a seat body 11 and a stress buffer tube 12 connected between the seat body 11 and the outer tube 2.

[0045] The seat 11 can be a conventional Luer connector, which has an internal inflation / deflation channel to fill the balloon 3 with a medium, so as to expand and dilate the narrowed part of the blood vessel, thus meeting the connection and sealing requirements of the device delivery channel and the inflation / deflation channel.

[0046] The stress buffer tube 12 is made of a thermoplastic polymer with good elasticity, such as TPU or Pebax. It is mainly used to realize the connection between the seat 11 and the outer tube 2 and the gradual change of stiffness to ensure good performance.

[0047] The proximal end of the outer tube 2 is connected to the stress buffer tube 12, and the distal end is connected to the proximal end of the balloon 3. In this invention, the metal tube body 21 mainly provides strength and support for the entire catheter, ensuring its pushing effect. Therefore, the metal tube body 21 is set throughout the entire outer tube 2 and is formed of one of the following: high-strength and moderately elastic 304 stainless steel, 316 stainless steel, or nickel-titanium alloy, with a thickness of 0.001 to 0.002 inches. Among them, 340 stainless steel or 316 stainless steel can ensure that the tube body has high strength, good toughness, and excellent corrosion resistance; while nickel-titanium alloy can obtain superelasticity and shape memory properties, thus making it easier to pass through complex and tortuous vascular paths and reducing bending fatigue. By using these materials to make the metal tube body 21, sufficient rigidity and stability are ensured during long-distance pushing, thereby achieving efficient pushing force transmission and control in larger vascular segments (such as the aortic arch and its branches).

[0048] In one embodiment of the present invention, the length of the metal tube segment is twice the length of the composite tube segment. That is, on the metal tube body 21, the non-cut segment 22 serves as the main pushing body of the entire conduit, and its length is twice the length of the cut segment 23. Specifically, the length of the metal tube segment or the non-cut segment 22 is 1000-1200 mm, and the length of the composite tube segment or the cut segment 23 is 500-600 mm.

[0049] This allows the proximal end of the balloon dilation catheter to maintain sufficient strength and linear transmission performance when entering complex pathways such as intracranial blood vessels. At the distal end, the length of the composite tube is designed to cover the more tortuous and stenotic distal blood vessel segments. In addition, because the composite tube is a multi-layered composite structure formed by a coating process on the cut section 23, it achieves good flexibility and passability based on the characteristics of the composite tube. This ensures that the balloon 3 can reach the target position more accurately and smoothly during operation, improving the controllability and clinical applicability of the catheter in complex vascular anatomy.

[0050] In this embodiment, the cutting segment 23 includes a transition segment 230, a first cutting segment 231, a second cutting segment 232, and a third cutting segment 233 arranged sequentially from the proximal end to the distal end. The stiffness of the first cutting segment 231, the second cutting segment 232, and the third cutting segment 233 decreases sequentially. The first cutting segment 231 can be considered as starting from the first cutting groove at the proximal end. Thus, the uncut transition segment 230 is provided at the proximal end of the cutting segment 23, mainly used to connect the uncut segment 22 and the first cutting segment 231, allowing the inner lining layer to simultaneously cover this portion and ensuring the overall coverage of the first cutting segment 231.

[0051] By introducing a cutting section design with progressively decreasing stiffness from proximal to distal in the cutting section 23 of the metal tube body 21, a continuous and smooth stiffness gradient transition can be achieved within the distal composite tube segment of the outer tube 2. The first cutting section 231 retains high stiffness to ensure the stability of pushing in the proximal vascular segment, the second cutting section 232 has medium stiffness to ensure a smooth transition, and the third cutting section 233 has a softer characteristic, which is conducive to achieving good compliance and guidewire tracking in the narrower and more tortuous intracranial vascular segment at the distal end.

[0052] Specifically, such as Figure 3 As shown, in a preferred embodiment of the present invention, the stiffness requirements of each section in the cut segment 23 are achieved by the cutting method.

[0053] In the first cut section 231 near the proximal end, the stiffness reduction from the non-cut section 22 needs to be achieved at a relatively gentle slope, meaning it should have a high stiffness level and good flexural resistance. Therefore, the cutting method for this section is to select a spiral cutting pattern with connecting ribs, which includes a first main body portion 2311 extending spirally after cutting, a spiral groove 2312 formed axially between the first main body portions 2311, and multiple oblique connecting ribs 2313 passing through the spiral groove 2312 to connect adjacent first main body portions 2311. When the metal tube body 21 is unfolded on a plane, the oblique connecting ribs 2313 are arranged perpendicular to the first main body portion 2311. From the proximal end to the distal end, the width of the spiral groove 2312 gradually increases, meaning the stiffness of the first cut section 231 also gradually decreases. The aforementioned "relatively gentle slope" refers to the stiffness reduction slope of the first cut section 231 being 0.8 to 1.0 gf / mm.

[0054] The second cutting section 232 is an intermediate transition section, which needs to complete the reduction in stiffness towards the third cutting section 233 at a relatively fast slope, i.e., it has a medium stiffness level. Therefore, a pure helical cutting pattern is selected for this section. Thus, the second cutting section 232 has a helically extending second main body 2321 and a helical groove 2322 formed axially between two adjacent second main body parts 2321. The aforementioned "relatively fast slope" refers to the stiffness reduction slope of the second cutting section 232 being 2.0 to 2.2 gf / mm, which is greater than the stiffness reduction slope of the first cutting section 231.

[0055] The third cutting section 233 needs to transition towards a lower stiffness at a slower slope while maintaining a low stiffness level. Therefore, this section is designed with a grooved pattern. Specifically, this section has third main body parts 2331 spaced axially and extending in a ring shape in the circumferential direction, and a plurality of axial connecting ribs 2332 connecting adjacent third main body parts 2331. The aforementioned "slower slope" refers to the stiffness reduction slope of the third cutting section 233 being 0.1 to 0.2 gf / mm, which is less than the stiffness reduction slope of the first cutting section 231 and the second cutting section 232.

[0056] In one embodiment of the present invention, the first cutting segment 231 has a length of 110–130 mm, the second cutting segment 232 has a length of 150–170 mm, the third cutting segment 233 has a length of 220–240 mm, and the transition segment 230 has a length of 20–30 mm. By subdividing the cutting segment 23 into several segments with defined length ranges, the transition segment 230 is designed as a transition connection near the end of the cutting segment 23, with a shorter length and the same stiffness as the non-cutting segment 22.

[0057] For the other three cutting segments, the shorter and more robust first cutting segment 231 maintains high rigidity, ensuring effective transmission of the initial pushing force; the slightly longer second cutting segment 232 transitions with moderate rigidity, providing the catheter with appropriate compliance and stability when traversing moderately tortuous vascular segments; the longest and most flexible third cutting segment 233 at the distal end accommodates the deeper and more tortuous anatomy of intracranial vessels, further reducing the risk of catheter bending and coiling in the distal path. This improves the catheter's progressive adaptability to different vascular segments, allowing operators to more smoothly deliver the balloon 3 to the target site during clinical interventional treatment, ultimately enhancing catheter traceability and passageability.

[0058] The inner liner 24 is made of PTFE, which has low friction properties, helps improve the passage of internal instruments, and can increase the burst pressure of the tubing section, making the inflation and depressurization process of the balloon 3 smoother. The thickness of the inner liner 24 is 0.001 inches.

[0059] The sleeve 25 is made of nylon-like polymer material with heat shrink properties, so that it can fit tightly to the outside of the cut section 23 under heating conditions, while maintaining the overall small diameter of the outer tube 2 and giving it the required flexibility and high pushing performance.

[0060] In one embodiment of the present invention, the sleeve 25 is provided with a first pipe section, a second pipe section, and a third pipe section. The first pipe section covers the transition section 230 and the first cutting section 231, the second pipe section covers the second cutting section 232, and the third pipe section covers the third cutting section 233. The three pipe sections are matched with the characteristic of decreasing stiffness of the three cutting sections of the cutting section 23, and are also designed to gradually decrease in stiffness and gradually increase in flexibility. Specifically, the first pipe section is made of Pebax 7033 material, the second pipe section is made of Pebax 6333 material, and the third pipe section is made of Pebax 5533 material.

[0061] The first segment, made of Pebax 7033, has relatively high rigidity and can be paired with a metal-cut pattern structure with even higher rigidity to achieve effective transmission and support of the pushing force. The second segment, made of Pebax 6333, has medium rigidity and flexibility, allowing for a smoother transition in the intermediate transition zone. The third segment, made of Pebax 5533, has better flexibility, enabling excellent tracking performance and compliance when passing through tortuous and narrow blood vessel segments. The selection of the above segment materials can achieve a tight fit between the outer layer of the polymer cannula, the inner liner 24, and the metal tube body 21 through a heat condensation process. This creates a layered distribution of mechanical properties in the finished catheter, from rigid to flexible, ensuring that the catheter maintains sufficient rigidity at the proximal end to transmit the pushing force while achieving a smooth transition at the distal end during actual interventional procedures. Ultimately, this improves the catheter's passability and maneuverability in complex intracranial vascular pathways.

[0062] In one embodiment of the present invention, the balloon 3 is a cylindrical balloon made of a semi-compliant or non-compliant material to dilate the target vascular stenosis upon application of contrast agent or saline pressure. Specifically, the balloon 3 may be made of one of the following materials: Pebax 7033, Pebax 6333, PA11, or PA12. Furthermore, the shape of the balloon 3 may also be configured as curved, ellipsoidal, or step-shaped, depending on the indication.

[0063] In addition, such as Figure 1 As shown, the quick-connect balloon dilation catheter 100 also includes a tip tube 4 connected to the distal end of the balloon 3, an inner tube 5 disposed inside the outer tube 2, and a contrast ring 6 disposed on the inner tube 4.

[0064] The head tube 4 is a single-layer polymer single-lumen tube made of Pebax 5533 material, which is the same material as the third section of the aforementioned sleeve 25, facilitating their connection. The distal end of the head tube 4 is shaped into a pointed tip using a thermoforming mold or hot air to improve the catheter's permeability.

[0065] The inner tube 5 extends from the quick-joint 20 of the outer tube 2 to the distal end of the tip tube 4. The inner tube 5 and the outer tube 2 are sealed together at the quick-joint 20 and at the distal end of the tip tube 4, so as to divide the lumen at the distal end of the balloon dilation catheter 100 into an filling lumen 101 formed between the outer tube 2 and the inner tube 5 and between the balloon 3 and the inner tube, and a guidewire lumen 102 located in the inner tube 5.

[0066] Specifically, in this embodiment, the inner tube 5 is a three-layer polymer single-lumen tube. The outer layer is made of PA11 material to provide the main mechanical properties of the inner tube 5; the inner layer is made of HDPE material to reduce friction and ensure instrument delivery within the guidewire lumen 102; and the middle layer is made of LLDPE material, primarily providing the connection between the inner and outer layers. The thickness ratio of the outer layer to the combined thickness of the middle and inner layers in the inner tube 5 is 75:25. The overall thickness is 0.002 inches.

[0067] The imaging ring 6 is a circular structure and is arranged in pairs at intervals on the outside of the inner tube 5, specifically at the position corresponding to the inner tube 5 and the balloon 3.

[0068] Specifically, the imaging ring 6 is made of a radiopaque metallic material, such as gold, platinum-iridium, tantalum, or other high-density metals. It is tightly fixed to the outside of the inner tube 5 using methods such as adhesive bonding, interference fit, laser welding, acoustic welding, melting, and pressing, so that it can accurately reach the designated lesion site under imaging technology. In this embodiment, the imaging ring 6 has a width of approximately 0.6 mm and a thickness of 0.001 inches.

[0069] The quick-connection port 20 is disposed inside and outside the composite tube section of the outer tube 4, and is located 240-280 mm away from the distal end of the quick-connection balloon dilation catheter 100.

[0070] By precisely spacing quick-connect joints 20 on the distal composite segment of the outer tube 2, the inner tube 5 is coaxial with the outer tube 2 only in this shorter section, thus achieving a rapid exchange structure. This distance is chosen considering both the complexity of the vascular pathway and instrument accessibility, while maintaining sufficient rigidity and support. This configuration also reduces the overall coaxial length of the catheter, allowing operators to quickly change or adjust instruments without using excessively long guidewires, simplifying the procedure. Furthermore, when the catheter is located in complex intracranial vessels, this specific distance helps maintain the stability and precision of the catheter during advancement and withdrawal, resulting in superior controllability and operational efficiency in clinical interventional therapy.

[0071] This invention also provides a method for preparing a balloon dilation catheter, which specifically includes the following steps:

[0072] A metal tube body is provided, the metal tube body having a non-cut section located at a proximal end and a cut section connected to the distal end of the non-cut section;

[0073] An expansion mandrel that can be expanded by heating is provided, and a polymer inner liner is fitted around the expansion mandrel;

[0074] An expansion mandrel with an inner lining is inserted into the metal tube body, so that the inner lining is located inside the cut section.

[0075] The expansion mandrel is heated to expand it, thereby fixing the inner liner to the inside of the cut section;

[0076] The polymer sleeve is fitted onto the outside of the cutting section to cover the outer wall of the cutting section, so that the cutting section of the metal pipe body forms a composite pipe section.

[0077] Remove the expansion mandrel.

[0078] In this embodiment, the balloon dilation catheter is the aforementioned quick-connect balloon dilation catheter 100. Of course, this method is also applicable to other catheter applications with the aforementioned polymer inner liner, polymer sheath 25 and corresponding metal tube body 21.

[0079] Therefore, in this embodiment, the metal tube body is the metal tube body 21 of the outer tube 2 as described above, the polymer inner liner is the inner liner 24 covering the inner side of the cut section 23 of the metal tube body 21, and the polymer sleeve is the polymer sleeve 25 covering the outer side of the cut section 23 of the metal tube body 21. Its specific structure and material settings are the same as described above, and will not be repeated here.

[0080] In the above-mentioned preparation method of the present invention, the inner liner 24 is mainly installed and fixed by using an expansion mandrel, which can greatly increase the flexibility of the design, improve the adaptability of raw materials and design flexibility, reduce the outer diameter of the conduit, and improve the conduit's passability; at the same time, it simplifies the process, reduces the use of auxiliary consumables, and lowers production costs.

[0081] Specifically, in the above preparation method, the length of the inner liner 24 is cut to match the length of the cut segment 23 of the metal tube body 21. Since the proximal end of the cut segment 23 has an uncut transition section 230 with a length of 20-30 mm, this ensures that it can completely cover all the cut segments in the cut segment 23. A positioning ring is provided on the expansion mandrel to facilitate moving the inner liner 24 to the corresponding position of the cut segment 23.

[0082] The expansion mandrel in this invention is a solid shaft with the characteristic of thermal expansion. It can be made of PTFE or FEP material; in this embodiment, FEP material is used. By using this type of expansion mandrel, the outer diameter of the entire mandrel is controllable and insensitive to assembly gaps. Consequently, in the above-mentioned preparation method, the size of the outer tube 2 does not need to be adapted to the size of the mandrel, allowing its outer diameter to be set sufficiently small according to usage requirements. This increases design flexibility and achieves a comprehensive improvement in the design, manufacturing, performance, and adaptability of the conduit.

[0083] When placing the expansion mandrel inside the metal tube body 21, both ends of the expansion mandrel extend beyond the cut section 23 to ensure the covering and adhesion effect of the inner lining layer 24. Furthermore, the extension length of the expansion mandrel at the distal end of the cut section is not less than 10 cm, thereby facilitating clamping and core extraction of the expansion mandrel after preparation.

[0084] As one embodiment of the present invention, in the above preparation method, "heating the expansion mandrel" specifically includes:

[0085] First, the expansion mandrel is pre-expanded and heated so that after the expansion mandrel is pre-expanded, the inner lining 24 contacts the inner wall of the cut section 23 of the metal tube body 21, so as to achieve relative fixation of the expansion mandrel, the inner lining 24 and the metal tube body 21.

[0086] Then, a laminating machine is used to heat and expand the inner lining 24 so that it adheres to the inside of the metal tube body 21.

[0087] In practice, the expansion mandrel can be pre-expanded and heated using a hot air blower or a horizontally positioned laminating machine, causing it to expand slowly. This allows the inner lining layer 24, which is mounted on it, to adhere to the inner wall of the cut section 23, thus achieving initial adhesion and fixing of their relative positions in the radial direction. On one hand, the pre-expansion operation of the expansion mandrel eliminates internal stress, reduces deformation and twisting during use, and ensures that the material maintains better stability and precision during use, laying the foundation for subsequent reheating and expansion to achieve a better expansion effect. On the other hand, by pre-expanding to relative position the expansion mandrel, inner lining layer, and metal tube body 21, the secondary heating and expansion does not require consideration of the equipment environment used, avoiding relative displacement between the expansion mandrel, inner lining layer, and metal tube body.

[0088] In one embodiment of the present invention, the expansion mandrel is made of FEP material, the inner diameter of the metal tube body 21 is approximately 0.036 inches, and the wall thickness is approximately 0.0015 inches. In this case, the outer diameter of the expansion mandrel can be configured to be approximately 0.025 inches. Furthermore, since hot air blowers are less expensive than laminating machines, they are used for pre-expansion heating at a temperature of 180–200°C for 1–2 minutes.

[0089] During the secondary heating and expansion, a laminating machine is used, with a heating temperature of 180–200℃ and a moving speed of 3–5 mm / s. This ensures sufficient expansion of the expansion mandrel, allowing the inner lining layer 24 to adhere more tightly and evenly to the inside of the metal tube cut section 23, forming a highly coaxial and structurally stable base layer. This step-by-step approach of pre-expansion and laminating machine heating helps reduce the risk of uneven stress and poor deformation caused by rapid, one-time expansion during processing, and provides a more ideal underlying structure in the subsequent step of fitting the heat-shrinkable polymer sleeve.

[0090] In the above preparation method, the polymer sleeve 25 is a sleeve with heat shrinkability, which can be directly heat-shrink and fixed to the outside of the cut section 23 by heating, avoiding the use of heat shrink tubing and its removal step, reducing the use of auxiliary consumables and simplifying the process.

[0091] The assembly and fixing steps of the polymer sleeve can be implemented using the following two methods:

[0092] Option 1 involves fitting the polymer sleeve 25 onto the outside of the cut section of the metal tube body after "pre-expansion heating of the expansion mandrel" and before "heating and expansion using a coating machine".

[0093] This design allows the polymer sleeve 25 to be fitted into the inner liner 24 and the metal tube body 21 after they have been initially fixed. Then, during the subsequent heating process of the laminating machine, the sleeve 25 is heated and bonded together, reducing the number of process steps and maintaining overall coaxiality and wall thickness uniformity.

[0094] Option 2: After the polymer sleeve 25 is heated and expanded using a coating machine, it is fitted onto the outside of the cut section 23 of the metal tube body 21. In this case, the preparation method further includes: heating again using a coating machine to heat shrink and fix the polymer sleeve to the outside of the cut section 23.

[0095] In other words, Option 2 involves an additional heating process compared to Option 1. However, Option 2 allows for independent fine-tuning of the outer layer structure without affecting the previously established stable inner diameter control and adhesion, adapting to the characteristics of different materials or batches of raw materials, thereby improving process flexibility. Furthermore, this option eliminates the need to consider the matching requirements of the heating temperature of the expansion mandrel and the polymer sleeve 25, allowing for optimal configuration based on their materials.

[0096] Furthermore, as mentioned earlier, when the polymer sleeve 25 adopts a three-segment progressive design (from the proximal end to the distal end, the first segment uses Pebax 7033 material, the second segment uses Pebax 6333 material, and the third segment uses Pebax 5533 material), during the heating process of the laminating machine in Scheme 1 or the re-laminating heating process in Scheme 2, the moving speed is set differently according to different segments. Specifically, for example, the moving speed of the third segment using Pebax 5533 material can be set to 3.5 mm / s, the moving speed of the second segment using Pebax 6333 material can be set to 3 mm / s, and the moving speed of the first segment using Pebax 7033 material can be set to 2.5 mm / s.

[0097] In this embodiment, the expansion mandrel is extracted by using a guide tube stretching machine to fix the clamp on the expansion mandrel and extract the mandrel at a speed of 3-6 mm / s.

[0098] In addition to the above-described preparation method, the preparation method of the balloon dilation catheter also includes:

[0099] After the expansion mandrel is removed, a quick joint is formed in the composite pipe section;

[0100] After forming the quick-joint, an inner tube is installed inside the metal tube body through the quick-joint, and the two are welded together at the quick-joint position.

[0101] Specifically, after the expansion mandrel is extracted, precision grinding or drilling is performed on the distal composite pipe section to form a quick-connection 20 with a predetermined position and size.

[0102] Then, the pre-prepared inner tube 5 is inserted into the inner side of the metal tube body 21 along the quick-connect joint 20, and the inner tube 5 is fixedly connected to the outer tube 2 at the quick-connect joint 20 by appropriate laser welding or thermal welding. This connection method ensures that the inner tube 5 achieves stable axial positioning and pressure sealing in the quick-connect section, while also enabling the catheter to have rapid exchange characteristics. The operator can use a shorter guidewire to advance or withdraw the catheter individually, significantly simplifying the operation and shortening the operation time.

[0103] Through the above preparation steps, a balloon dilation catheter with zoned gradual stiffness, low outer diameter, high coaxiality and rapid exchange characteristics is finally obtained, which greatly improves the passability, maneuverability and ease of operation in complex clinical scenarios such as tortuous and narrow intracranial blood vessels.

[0104] It should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0105] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A quick-connect balloon dilation catheter, comprising a catheter seat, an outer tube connected to the catheter seat, and a balloon connected to the distal end of the outer tube, characterized in that: The outer tube has a metal tube body extending from the proximal end to the distal end. The metal tube body has a non-cut section at the proximal end and a cut section connected to the distal end of the non-cut section. The outer tube also has a polymer inner liner covering the inside of the cut section and a polymer sleeve covering the outside of the cut section, so that the outer tube is formed as a whole into a composite tube section having a metal tube section at the proximal end and a composite tube section connected to the distal end of the metal tube section. The composite tube section is provided with a quick-connect joint that runs through both the inside and outside.

2. The quick-connect balloon dilation catheter as described in claim 1, characterized in that, The length of the metal pipe section is twice the length of the composite pipe section, the length of the metal pipe section is 1000-1200mm, and the length of the composite pipe section is 500-570mm.

3. The quick-connect balloon dilation catheter as described in claim 1, characterized in that, The main body of the metal tube is made of one of 340 stainless steel, 316 stainless steel or nickel-titanium alloy, the inner lining is made of PTFE material, and the sleeve is made of nylon-like polymer material with heat shrink properties.

4. The quick-connect balloon dilation catheter as described in claim 3, characterized in that, The cutting segment includes a transition segment, a first cutting segment, a second cutting segment, and a third cutting segment arranged sequentially from the proximal end to the distal end, with the stiffness of the first cutting segment, the second cutting segment, and the third cutting segment decreasing sequentially.

5. The quick-connect balloon dilation catheter as described in claim 4, characterized in that, The stiffness decrease slope of the first cutting section 231 is 0.8 to 1.0 gf / mm, the stiffness decrease slope of the second cutting section 232 is 2.0 to 2.2 gf / mm, and the stiffness decrease slope of the third cutting section 233 is 0.1 to 0.2 gf / mm.

6. The quick-connect balloon dilation catheter as described in claim 4, characterized in that: The length of the first cutting section is 110-130mm, the length of the second cutting section is 150-170mm, the length of the third cutting section is 220-240mm, and the length of the transition section is 20-30mm.

7. The quick-connect balloon dilation catheter as described in claim 4, characterized in that: The sleeve is provided with a first pipe section, a second pipe section and a third pipe section. The first pipe section covers the transition section and the first cutting section, the second pipe section covers the second cutting section and the third pipe section covers the third cutting section. The first pipe section is made of Pebax 7033 material, the second pipe section is made of Pebax 6333 material and the third pipe section is made of Pebax 5533 material.

8. The quick-connect balloon dilation catheter as described in claim 1, characterized in that: The quick-connection port is located 240–280 mm from the distal end of the quick-connect balloon dilation catheter.

9. A method for preparing a balloon dilation catheter, characterized in that, The preparation method includes: A metal tube body is provided, the metal tube body having a non-cut section located at a proximal end and a cut section connected to the distal end of the non-cut section; An expandable mandrel that can be expanded by heating is provided, and a polymer inner liner is placed around the expandable mandrel; An expansion mandrel with an inner lining is inserted into the metal tube body, so that the inner lining is located inside the cut section. The expansion mandrel is heated to expand it, thereby fixing the inner liner to the inside of the cut section; The polymer sleeve is fitted onto the outside of the cutting section to cover the outer wall of the cutting section, so that the cutting section of the metal pipe body forms a composite pipe section. Remove the expansion mandrel.

10. The method for preparing the balloon dilation catheter as described in claim 9, characterized in that: The length of the inner lining layer is greater than the length of the cut section. When the expansion mandrel is placed inside the metal tube body, both ends of the expansion mandrel extend out of the cut section, and the extension length of the expansion mandrel at the far end of the cut section is not less than 10cm.

11. The method for preparing the quick-connect balloon dilation catheter as described in claim 10, characterized in that: The metal tube body is made of one of 340 stainless steel, 316 stainless steel or nickel-titanium alloy, the inner lining is made of PTFE, the sleeve is made of nylon-like polymer material with heat shrink properties, and the expansion mandrel is made of PTFE or FEP material.

12. The method for preparing the balloon dilation catheter as described in claim 9, characterized in that: "Heating the expansion mandrel" specifically includes: First, the expansion mandrel is pre-expanded and heated so that after the expansion mandrel is pre-expanded, the inner lining layer contacts the inner wall of the cut section of the metal tube body, so as to achieve relative fixation of the expansion mandrel, the inner lining layer and the metal tube body; Then, a coating machine is used to heat and expand the inner lining so that it adheres to the inside of the metal tube body.

13. The method for preparing the balloon dilation catheter as described in claim 12, characterized in that: The expansion mandrel is made of FEP material. During pre-expansion heating, a hot air blower is used, the heating temperature is 180-200℃, and the heating time is 1-2 minutes. When reheating using a laminating machine, the heating temperature is 180-200℃, and the moving speed is 3-5 mm / s.

14. The method for preparing the balloon dilation catheter as described in any one of claims 12 or 13, characterized in that: The polymer sleeve is fitted onto the outside of the cut section of the metal tube body after "pre-expansion heating of the expansion mandrel" and before "heating and expansion using a coating machine"; Alternatively, after the polymer sleeve is heated and expanded using a coating machine, it is fitted onto the outside of the cut section of the metal tube body. In this case, the preparation method further includes: heating again using a coating machine to heat-shrink and fix the polymer sleeve to the outside of the cut section.

15. The method for preparing the balloon dilation catheter as described in claim 14, characterized in that: The cutting segment includes a transition segment, a first cutting segment, a second cutting segment, and a third cutting segment arranged sequentially from the proximal end to the distal end, with the stiffness of the first cutting segment, the second cutting segment, and the third cutting segment decreasing sequentially; the polymer sleeve is provided with a first tube segment, a second tube segment, and a third tube segment, with the first tube segment covering the transition segment and the first cutting segment, the second tube segment covering the second cutting segment, and the third tube segment covering the third cutting segment; the first tube segment is made of Pebax 7033 material, the second tube segment is made of Pebax 6333 material, and the third tube segment is made of Pebax 5533 material.

16. The method for preparing the balloon dilation catheter as described in claim 14, characterized in that: The length of the non-cutting segment is twice the length of the cutting segment. The length of the non-cutting segment is 1000-1200mm, and the length of the cutting segment is 500-570mm. The length of the first cutting segment is 110-130mm, the length of the second cutting segment is 150-170mm, the length of the third cutting segment is 220-240mm, and the length of the transition segment is 20-30mm.

17. The method for preparing the balloon dilation catheter as described in claim 9, characterized in that: The preparation method further includes: After the expansion mandrel is removed, a quick joint is formed in the composite pipe section; After forming the quick-joint, an inner tube is installed inside the metal tube body through the quick-joint, and the two are welded together at the quick-joint position.

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