Microcatheter assembly and method of making

Abstract

The application discloses a micro catheter assembly and a preparation method thereof, and comprises a tube body and a guide wire which can be inserted into the catheter, and the tube body is sequentially provided with a polytetrafluoroethylene lining tube, a metal braided layer, an outer polymer tube and a hydrophilic coating from inside to outside; wherein the tube body is provided with a first embedded ring and a second embedded ring at a position with a preset distance from the tail end; the first embedded ring and the second embedded ring are spliced together and arranged on the metal braided layer and between the polytetrafluoroethylene lining tube and the outer polymer tube. The micro catheter has a tear mark and an embedded ring, so that the operator can easily disconnect the micro catheter at the tear mark without using scissors or other tools, thereby simplifying the withdrawal process of the micro catheter and avoiding the complicated operation in the traditional method.

Description

Technical Field

[0001] This invention relates to the field of medical devices, and more particularly to a microcatheter assembly and its preparation method. Background Technology

[0002] In neurointerventional surgery, the application of guidewire technology is a key step in achieving precise interventional treatment. Currently, the guidewires widely used in clinical practice are generally of standard length (e.g., 200 cm), mainly used for navigation within blood vessels, passing through narrowed, occluded, or tortuous segments of blood vessels.

[0003] However, existing technologies have some obvious shortcomings.

[0004] On the one hand, when using a 200 cm standard guidewire in conjunction with a microcatheter to enter the blood vessel lumen through complex occlusive lesions, the insufficient length of the guidewire often makes it difficult to withdraw the microcatheter.

[0005] On the other hand, due to the limited length of the guidewire, surgeons often need to change the guidewire multiple times when dealing with complex vascular anatomy, or cut the microcatheter with scissors before withdrawing it along the guidewire. This not only increases the difficulty and time of the procedure, but may also lead to additional risks of vascular injury or hemorrhagic shock, thus affecting the overall safety of the surgery. Summary of the Invention

[0006] Purpose of the invention: The purpose of this invention is to solve the technical problems in the prior art and provide a microcatheter assembly and its preparation method.

[0007] Technical solution: This application proposes a microcatheter assembly, including a tube body and a guidewire, wherein the guidewire is insertable into the catheter, comprising: The tube body is composed of a polytetrafluoroethylene inner liner, a metal braided layer, an outer polymer tube, and a hydrophilic coating from the inside out. The tube body is provided with a first fitting ring and a second fitting ring at a predetermined distance from the end; The first and second interlocking rings are spliced ​​together and disposed in the metal braided layer, and are disposed between the polytetrafluoroethylene inner liner tube and the outer polymer tube; The tube body has a developing ring on the outer side of its end, and the tube body has tear marks at the positions of the first and second interlocking rings.

[0008] Preferably, both the first and second interlocking rings have interlocking protrusions.

[0009] Preferably, the guide wire can be extended by connecting with a stainless steel core wire, wherein a connecting sleeve is provided on the outer side of the connection position between the guide wire and the stainless steel core wire.

[0010] Preferably, the connecting sleeve is made of at least one of polytetrafluoroethylene, polyester, fluorinated ethylene propylene copolymer, and polyolefin.

[0011] Preferably, the guide wire and the stainless steel core wire do not overlap, and the gap between their endpoints inside the connecting sleeve is 0~0.5mm; The guidewire specifications range from 0.014 inches to 0.018 inches; The outer diameter of the connecting sleeve before heat shrinking is 0.4~1.0mm, the inner diameter after heat shrinking is 0.2~0.5mm, and the wall thickness after heat shrinking is 0.03~0.09mm. The length of the connecting sleeve is 4~8cm; The length of the stainless steel core wire fixed to the connecting sleeve is 2~4cm; The length of the guidewire and connecting sleeve is 2-4 cm. The guide wire and stainless steel core wire have a hydrophilic coating on their surfaces; The distal end of the stainless steel core wire has a non-hydrophilic coating and is 2-4 cm in length.

[0012] This application proposes a method for fabricating a microcatheter assembly, comprising the following steps: Step 101: Secure the polytetrafluoroethylene (PTFE) liner tube inside the pre-prepared mandrel. Step 102: Thread the developing ring onto the polytetrafluoroethylene inner liner tube; Step 103: Assemble the first and second interlocking rings and place them on the outside of the polytetrafluoroethylene inner liner tube according to the preset position between them and the developing ring; Step 104: Place the polytetrafluoroethylene inner liner tube on a braiding machine to braid the metal braid layer; Step 105: Use a laser welding machine to weld the metal braided layer to the connection between the first and second interlocking rings, and use laser cutting to remove the overlapping area between the metal braided layer and the first and second interlocking rings; Step 106: Insert the outer polymer tube onto the outside of the metal braided layer, heat it through a high-temperature heat shrinking process, and remove the tube from the mandrel. Step 107: Injection mold a microcatheter seat into the proximal end of the outer polymer tube, and then generate a hydrophilic coating through a hydrophilic coating process; Step 108: Use a circumferential cutting tool to cut a tear mark on the surface of the hydrophilic coating. Then use a hot air gun to heat melt the cut to remove the burrs and make the surface of the tear mark smooth. The distance between the tear mark and the end of the microcatheter is a preset distance.

[0013] Preferably, the high-temperature heating temperature is 300°C to 400°C.

[0014] Preferably, the preset distance is 60cm-90cm.

[0015] Preferably, the method for extending the guidewire is as follows: Step 101: Turn on the hot air gun and heat it to the temperature at which the connecting sleeve can retract; Step 102: Cut the connecting sleeve to an appropriate length; Step 103: Thread one end of the connecting sleeve onto the far end of the stainless steel core wire, inserting it to a depth of 2-4 cm; Step 104: Then place it at the nozzle of the hot air gun to heat the part of the connecting sleeve that is inserted into the sleeve. Do not heat the part that is not inserted into the sleeve. Let it cool to room temperature. The guide wire extension is now complete. Step 105: Insert the proximal end of the guide wire into the distal end of the guide wire extension and align it with the end of the stainless steel core wire. The gap between the two ends inside the connecting sleeve should be 0~0.5mm. Step 106: Then place it on the nozzle of the hot air gun to heat the sleeve part of the connecting tube, cool it at room temperature, and the connection between the guide wire and the stainless steel core wire is completed.

[0016] Preferably, the heating temperature of the hot air gun is set to 120°C~350°C. Beneficial effects

[0017] By using heat-shrink tubing to wrap the guidewire and stainless steel core wire, this invention effectively extends the guidewire length, avoiding the cumbersome procedures of repeatedly replacing the guidewire or cutting the microcatheter due to insufficient guidewire length in traditional techniques. This method of extending the guidewire not only simplifies the operation steps but also improves surgical efficiency and reduces surgical time.

[0018] The guidewire extension method used in this invention is simple, convenient, and quick, enabling guidewire extension without the need for additional tools. Doctors can rapidly adjust the guidewire length, avoiding the complex steps of traditional methods such as guidewire replacement or cutting of the microcatheter with scissors, thus significantly reducing the difficulty of the procedure.

[0019] By extending the effective working length of the guidewire, multiple guidewire replacements or microcatheter cutting can be avoided, thereby reducing surgical risks such as vascular injury and hemorrhagic shock, and improving the overall safety of the surgery.

[0020] The microcatheter design in this invention features a tear mark and a locking ring, allowing the operator to easily disconnect the microcatheter at the tear mark without the need for scissors or other tools. This simplifies the microcatheter removal process and avoids the complex operations of traditional methods.

[0021] The materials and manufacturing processes used in this invention are simple and inexpensive, making them suitable for rapid on-site fabrication. This gives the invention greater economic efficiency and versatility in practical applications.

[0022] The guidewire extension design makes the connection between the guidewire and the stainless steel core wire more secure, enhancing the connection performance and safety of both, and ensuring the stability and effectiveness of the guidewire throughout the entire surgical procedure. Attached Figure Description

[0023] Figure 1 A schematic diagram of the tube structure is provided for this invention; Figure 2 For the present invention Figure 1 Schematic diagram of the cross-sectional structure at position A in the middle; Figure 3 A schematic diagram of the three-dimensional structure of the first interlocking ring is provided for this invention; Figure 4 A schematic diagram of the connecting sleeve structure is provided for this invention; Figure 5 This invention provides a schematic diagram of the guide wire and stainless steel core wire structure; Figure 6 A schematic diagram of the hot air gun structure is provided for this invention; Figure 7 A schematic diagram of the first interlocking ring structure is provided for the present invention.

[0024] Reference numerals: 1. Tube body; 2. Seat; 3. Outer polymer tube; 4. Metal braided layer; 51. First interlocking ring; 52. Second interlocking ring; 6. Polytetrafluoroethylene inner liner; 10. Guide wire; 11. Stainless steel core wire; 12. Connecting sleeve; 13. Hot air gun. Detailed Implementation

[0025] To make the technical solution of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Example

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art. The terms "comprising" and similar expressions used herein mean that the element or object preceding the word covers the element or object listed following the word and its equivalents, but do not exclude other elements or objects.

[0027] In response to the problems existing in the current technology, such as Figures 1-7 As shown, a microcatheter assembly is proposed, including a tube body 1 and a guidewire 10, wherein the guidewire 10 is insertable into the catheter, comprising: The tube body 1 is configured from the inside out as follows: a polytetrafluoroethylene inner liner 6, a metal braided layer 4, an outer polymer tube 3, and a hydrophilic coating. PTFE inner liner 6: This inner liner provides good lubrication and a low coefficient of friction, ensuring that the guide wire can pass smoothly.

[0028] Metal braided layer 4: This metal braided layer enhances the bending resistance and support performance of the tube, providing the necessary structural strength.

[0029] Outer polymer tube 3: Covered by a metal braided layer and a polytetrafluoroethylene inner liner, ensuring a smooth external structure of the tube and preventing increased friction within the blood vessel.

[0030] Hydrophilic coating: The hydrophilic coating helps reduce resistance during microcatheter insertion into blood vessels, improving the smoothness of the procedure.

[0031] The tube body 1 is provided with a first fitting ring 51 and a second fitting ring 52 at a predetermined distance from the end; At a predetermined distance from the end of the tube body 1, a first interlocking ring 51 and a second interlocking ring 52 are provided. These two rings are spliced ​​together and disposed within the metal braided layer 4, located between the polytetrafluoroethylene inner liner tube 6 and the outer polymer tube 3. The functions of these two interlocking rings include: To prevent the ends of the braided layer from loosening and to enhance the radial support of the tube body.

[0032] Provides reference locations for microcatheter disassembly when needed, facilitating operation. The first interlocking ring 51 and the second interlocking ring 52 are spliced ​​together and disposed in the metal braided layer 4, and are disposed between the polytetrafluoroethylene inner liner tube 6 and the outer polymer tube 3. The tube body 1 has a developing ring 102 on the outer side of its end, and the tube body 1 has a tear 101 at the position of the first fitting ring 51 and the second fitting ring 52.

[0033] The outer end of the tube 1 is provided with a radiopaque ring 102, which serves as an X-ray imaging marker to help doctors accurately locate the microcatheter and assist in surgical procedures. The tube 1 has tear marks 101 at the positions of the first interlocking ring 51 and the second interlocking ring 52. The tear marks allow surgeons to easily and manually cut the microcatheter along these marks when necessary, without the need for scissors or other tools, thus simplifying the procedure and reducing secondary injury to the patient and surgical time.

[0034] In some specific embodiments, both the first fitting ring 51 and the second fitting ring 52 are provided with interlocking protrusions. The stability between the first fitting ring 51 and the second fitting ring 52 is stronger.

[0035] In some specific embodiments, the guide wire 10 can be extended by connecting with the stainless steel core wire 11, wherein a connecting sleeve 12 is sleeved on the outside of the connection position between the guide wire 10 and the stainless steel core wire 11.

[0036] The guidewire 10, connected to the stainless steel core wire 11, can effectively extend the working length of the guidewire to meet the needs in complex vascular anatomy situations. The connecting sleeve 12 is a tubular heat-shrinkable sleeve. The outer diameter of the sleeve can be reduced after heating, tightly covering the connection between the guidewire 10 and the stainless steel core wire 11 to ensure a stable connection between the two.

[0037] In some specific embodiments, a seat 2 and a sheath tube are also included, wherein the seat 2 is connected to the tube body 1 through the sheath tube 201.

[0038] In some specific embodiments, the connecting sleeve 12 is made of at least one of polytetrafluoroethylene (PTFE), polyester, fluorinated ethylene propylene copolymer, and polyolefin. The heat-shrinkable sleeve material can be selected from PTFE, polyester (PET), fluorinated ethylene propylene copolymer (FEP), polyolefin (PO), etc., as these materials have excellent corrosion resistance and thermal stability, making them suitable for use in medical environments.

[0039] In some specific embodiments, the guide wire 10 and the stainless steel core wire do not overlap, and the gap between their endpoints inside the connecting sleeve 12 is 0~0.5mm; the guide wire 10 and the stainless steel core wire 11 do not overlap, and the gap between their endpoints inside the connecting sleeve 12 is 0~0.5mm. This design ensures a stable connection between the guide wire and the stainless steel core wire, while avoiding friction and interference between them.

[0040] Guidewire 10 is available in sizes from 0.014 inches to 0.018 inches; guidewire 10 is available in sizes from 0.014 inches to 0.018 inches (approximately 0.36 mm to 0.46 mm), and is compatible with most catheters and microcatheters used in neurointerventional procedures.

[0041] The outer diameter of the connecting sleeve before heat shrinking is 0.4~1.0mm, the inner diameter after heat shrinking is 0.2~0.5mm, and the wall thickness after heat shrinking is 0.03~0.09mm. The length of the connecting sleeve is 4-8 cm; the outer diameter of the connecting sleeve 12 is 0.4 mm to 1.0 mm before heat shrinking, the inner diameter is 0.2 mm to 0.5 mm after heat shrinking, and the wall thickness is 0.03 mm to 0.09 mm after heat shrinking. These dimensions ensure that the connecting sleeve can tightly wrap the guide wire and stainless steel core wire after heating, and has a small wall thickness to avoid increasing unnecessary volume and friction.

[0042] The length of the connecting sleeve is 4cm to 8cm to ensure sufficient length for a secure connection.

[0043] The length of the stainless steel core wire 11 fixed to the connecting sleeve 12 is 2~4cm; The length of the guide wire 10 and the connecting sleeve 12 is 2~4cm; The guide wire 10 and the stainless steel core wire 11 have a hydrophilic coating on their surfaces; The fixed length of the stainless steel core wire 11 and the connecting sleeve 12 is 2cm to 4cm to ensure a stable connection and prevent slippage. The fixed length of the guide wire 10 and the connecting sleeve 12 is 2cm to 4cm to ensure a firm connection of the guide wire extension and prevent loosening during operation.

[0044] The distal end of the stainless steel core wire 11 has a non-hydrophilic coating and a length of 2-4 cm.

[0045] Both the guidewire 10 and the stainless steel core wire 11 are coated with a hydrophilic coating to reduce friction during blood vessel insertion and improve the smoothness of the procedure. The distal end of the stainless steel core wire 11 is coated with a non-hydrophilic coating, with a length of 2 cm to 4 cm. This coating is designed to improve the guidewire's operative performance at specific sites and reduce its adhesion to the blood vessel wall.

[0046] This application proposes a method for fabricating a microcatheter assembly, comprising the following steps: Step 101: Secure the PTFE inner liner tube 6 inside the pre-prepared mandrel; this step ensures the stability of the inner liner tube during subsequent weaving and heating processes.

[0047] Step 102: Attach the imaging ring 102 to the polytetrafluoroethylene inner liner tube 6; the imaging ring 102 is used as an imaging marker for X-rays to help doctors accurately locate the microcatheter. Step 103: Assemble the first interlocking ring 51 and the second interlocking ring 52 and place them on the outside of the polytetrafluoroethylene inner liner tube 6 according to the preset position between them and the developing ring 102; ensure that the position of each part is accurate; Step 104: Place the polytetrafluoroethylene inner liner 6 on a braiding machine to braid the metal braid layer 4; the metal braid layer 4 enhances the microcatheter's resistance to bending and its support performance. Step 105: Use a laser welding machine to weld the metal braided layer 4 to the connection between the first interlocking ring 51 and the second interlocking ring 52, and use laser cutting to remove the overlapping area between the metal braided layer 4 and the first interlocking ring 51 and the second interlocking ring 52; ensure the strength and precision of the weld. Step 106: Insert the outer polymer tube 3 onto the outside of the metal braided layer 4, and heat it through a high-temperature heat shrinking process to remove the tube 1 from the mandrel; thus completing the formation of the tube structure. Step 107: Injection mold the microcatheter seat 2 into the proximal end of the outer polymer tube 3, and then generate a hydrophilic coating through a hydrophilic coating process. The hydrophilic coating reduces friction during blood vessel insertion. Step 108: Use a circumferential cutting tool to cut a tear mark 101 on the surface of the hydrophilic coating. Use a hot air gun to heat melt the cut to remove the burrs and make the surface of the tear mark 101 smooth. The distance between the tear mark 101 and the end of the microcatheter is a preset distance.

[0048] In some specific embodiments, the high-temperature heating temperature is 300°C to 400°C. This ensures that the tube 1 detaches smoothly from the mandrel and achieves stable shape. In some specific embodiments, the preset distance is 60cm-90cm.

[0049] In some specific embodiments, the guidewire 10 is extended using the following method: Step 101: Turn on the hot air gun 13 and heat it to the temperature at which the connecting sleeve 12 can shrink, usually between 120°C and 350°C, so that it can shrink after heating and firmly wrap the guide wire and stainless steel core wire. Step 102: Cut the connecting sleeve 12 to an appropriate length. According to the required extension of the guide wire, cut the connecting sleeve 12 to an appropriate length to ensure that its length is appropriate and can effectively cover the connection part of the guide wire and the stainless steel core wire. Step 103: Thread one end of the connecting sleeve onto the far end of the stainless steel core wire 11, inserting it to a depth of 2-4cm to ensure the firmness of the connection. Step 104: Then place it in the hot air gun nozzle to heat the through part of the connecting sleeve 12. Do not heat the non-through part. Let it cool to room temperature. The guide wire 10 extension is completed. After heating in the hot air gun nozzle, let it cool naturally to complete the production of the guide wire extension. Step 105: Insert the proximal end of the guide wire 10 into the distal end of the guide wire 10 extension and mate it with the end of the stainless steel core wire 11. The gap between the two ends in the connecting sleeve 12 is 0~0.5mm to ensure the tightness and stability of the connection. Step 106: Then place the part of the connecting sleeve 12 through the hot air gun nozzle to heat it, and let it cool to room temperature. The connection between the guide wire 10 and the stainless steel core wire 11 is now complete.

[0050] In some specific embodiments, the heating temperature of the hot air gun is set to 120°C~350°C.

[0051] The above description is merely a specific implementation of the embodiments of the present invention, but the protection scope of the embodiments of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the embodiments of the present invention should be covered within the protection scope of the embodiments of the present invention. Therefore, the protection scope of the embodiments of the present invention should be determined by the protection scope of the claims.

Claims

1. A microcatheter assembly comprising a body and a guidewire, the guidewire being insertable into the catheter, characterized in that, include: The tube body is composed of a polytetrafluoroethylene inner liner, a metal braided layer, an outer polymer tube, and a hydrophilic coating from the inside out. The tube body is provided with a first fitting ring and a second fitting ring at a predetermined distance from the end; The first and second interlocking rings are spliced ​​together and disposed in the metal braided layer, and are disposed between the polytetrafluoroethylene inner liner tube and the outer polymer tube; The tube body has a developing ring on the outer side of its end, and the tube body has tear marks at the positions of the first and second interlocking rings.

2. A microcatheter assembly according to claim 1, characterized in that, Both the first and second interlocking rings have interlocking protrusions.

3. A microcatheter assembly according to claim 1, characterized in that, The guide wire can be extended by connecting with a stainless steel core wire, wherein a connecting sleeve is provided on the outside of the connection position between the guide wire and the stainless steel core wire.

4. A microcatheter assembly according to claim 3, characterized in that, The connecting sleeve is made of at least one of polytetrafluoroethylene, polyester, fluorinated ethylene propylene copolymer, and polyolefin.

5. A microcatheter assembly according to claim 4, characterized in that, The guide wire and the stainless steel core wire do not overlap, and the gap between their endpoints inside the connecting sleeve is 0~0.5mm; The guidewire specifications range from 0.014 inches to 0.018 inches; The outer diameter of the connecting sleeve before heat shrinking is 0.4~1.0mm, the inner diameter after heat shrinking is 0.2~0.5mm, and the wall thickness after heat shrinking is 0.03~0.09mm. The length of the connecting sleeve is 4~8cm; The length of the stainless steel core wire fixed to the connecting sleeve is 2~4cm; The length of the guidewire and connecting sleeve is 2-4 cm. The guide wire and stainless steel core wire have a hydrophilic coating on their surfaces; The distal end of the stainless steel core wire has a non-hydrophilic coating and is 2-4 cm in length.

6. A method for fabricating a microcatheter assembly, characterized in that, Includes the following steps: Step 101: Secure the polytetrafluoroethylene (PTFE) liner tube inside the pre-prepared mandrel. Step 102: Thread the developing ring onto the polytetrafluoroethylene inner liner tube; Step 103: Assemble the first and second interlocking rings and place them on the outside of the polytetrafluoroethylene inner liner tube according to the preset position between them and the developing ring; Step 104: Place the polytetrafluoroethylene inner liner tube on a braiding machine to braid the metal braid layer; Step 105: Use a laser welding machine to weld the metal braided layer to the connection between the first and second interlocking rings, and use laser cutting to remove the overlapping area between the metal braided layer and the first and second interlocking rings; Step 106: Insert the outer polymer tube onto the outside of the metal braided layer, heat it through a high-temperature heat shrinking process, and remove the tube from the mandrel. Step 107: Injection mold a microcatheter seat into the proximal end of the outer polymer tube, and then generate a hydrophilic coating through a hydrophilic coating process; Step 108: Use a circumferential cutting tool to cut a tear mark on the surface of the hydrophilic coating. Then use a hot air gun to heat melt the cut to remove the burrs and make the surface of the tear mark smooth. The distance between the tear mark and the end of the microcatheter is a preset distance.

7. A method for preparing a microcatheter assembly according to claim 6, characterized in that, The high-temperature heating temperature is 300°C~400°C.

8. A method for preparing a microcatheter assembly according to claim 6, characterized in that, The preset distance is 60cm-90cm.

9. A method for preparing a microcatheter assembly according to claim 6, characterized in that, The microcatheter assembly also includes a guidewire that can be extended by connection with a stainless steel core wire, the extension of which is performed as follows: Step 101: Turn on the hot air gun and heat it to the temperature at which the connecting sleeve can retract; Step 102: Cut the connecting sleeve to an appropriate length; Step 103: Thread one end of the connecting sleeve onto the far end of the stainless steel core wire, inserting it to a depth of 2-4 cm; Step 104: Then place it at the nozzle of the hot air gun to heat the part of the connecting sleeve that is inserted into the sleeve. Do not heat the part that is not inserted into the sleeve. Let it cool to room temperature. The guide wire extension is now complete. Step 105: Insert the proximal end of the guide wire into the distal end of the guide wire extension and align it with the end of the stainless steel core wire. The gap between the two ends inside the connecting sleeve should be 0~0.5mm. Step 106: Then place it on the nozzle of the hot air gun to heat the sleeve part of the connecting tube, cool it at room temperature, and the connection between the guide wire and the stainless steel core wire is completed.

10. A method for preparing a microcatheter assembly according to claim 6, characterized in that, The heating temperature of the hot air gun is set to 120°C~350°C.

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