Composite micro guide wire

Abstract

The utility model belongs to the technical field of medical apparatus and instruments, especially relates to a composite micro guide wire. A composite micro guide wire, which comprises: an inner core, which is sequentially divided into a pushing section, a supporting section, a gradually changing section and a head end soft section along an axial direction from a proximal end to a distal end; a composite reinforcing layer, which comprises a braided mesh structure and a wire winding structure; the braided mesh structure is sleeved outside the supporting section and the gradually changing section of the inner core, and the wire winding structure is arranged in the head end soft section of the inner core; a polymer cladding layer, which is coated on the outer surface of the composite reinforcing layer. The composite micro guide wire can reduce radial pressure in a tortuous blood vessel, and has good pushing performance, supporting property and precise control ability while giving consideration to proximal control and distal flexibility, and is especially suitable for interventional operation of a complex blood vessel path.

Description

Technical Field

[0001] This utility model belongs to the field of medical device technology, and in particular relates to a composite microguidewire. Background Technology

[0002] As a key instrument for guiding catheters to the target position in interventional vascular surgery, microguidewires face multiple technical challenges in complex vascular pathway operations: for example, traditional single-coil guidewires have uneven torque transmission problems and are prone to tailing in tortuous blood vessels, making it difficult to achieve the expected torque control capability in clinical practice; although ordinary polymer sheathed guidewires have a smooth surface, they have insufficient pushing force and are prone to bending and deformation in tortuous blood vessels, making it impossible to effectively support catheter follow-up; although existing braided guidewires have high torque transmission efficiency, their excessive tip hardness leads to a low safety factor and is prone to vascular injury.

[0003] Based on this, the present invention provides a novel composite microwire to overcome the above-mentioned defects. Utility Model Content

[0004] The purpose of this invention is to provide a composite microguidewire that can reduce radial pressure in tortuous blood vessels, while taking into account both proximal maneuverability and distal flexibility. It has excellent pushing performance, support and precise control capabilities, and is especially suitable for interventional procedures in complex vascular pathways.

[0005] This utility model adopts the following technical solution: a composite microguidewire, comprising:

[0006] The inner core is divided into a pushing section, a supporting section, a gradient section and a soft head section along the axial direction from the proximal end to the distal end.

[0007] A composite reinforcement layer, comprising a woven mesh structure and a wound wire structure; the woven mesh structure is sleeved outside the support section and the gradient section of the inner core, and the wound wire structure is wound onto the soft section at the head end of the inner core.

[0008] A polymer coating layer is applied to the outer surface of the composite reinforcement layer.

[0009] Furthermore, the woven mesh structure is made of stainless steel or cobalt-chromium alloy.

[0010] Furthermore, the weaving density of the woven mesh structure is 30 to 120 cross points per inch.

[0011] Furthermore, the wire winding structure is made of platinum-tungsten or platinum-nickel alloy, and the pitch of the wire winding structure is 0.08 mm to 0.2 mm.

[0012] Furthermore, the proximal end of the composite microguidewire is coated with a hydrophobic coating, the thickness of which is 5–15 μm;

[0013] And / or, the distal end of the composite microguidewire is coated with a hydrophilic coating, the thickness of which is 2–10 μm.

[0014] Furthermore, the hydrophilic coating is loaded with heparin molecules.

[0015] Furthermore, the woven mesh structure is fitted over the support section and gradient section of the inner core through heat setting treatment, and the woven mesh structure includes a starting end and an ending end, both of which are fixedly connected to the inner core by laser welding or adhesive bonding.

[0016] Furthermore, the distal end of the wire winding structure is fixedly connected to the inner core by brazing, and the proximal end of the wire winding structure is fixedly connected to the inner core by brazing or adhesive bonding.

[0017] Furthermore, the proximal end of the winding structure extends to the distal end of the braided mesh structure, forming a braiding-winding transition zone; the length of the braiding-winding transition zone is 10cm to 15cm.

[0018] And / or, the braiding density of the braided mesh structure in the braiding-winding transition zone gradually decreases from the proximal end to the distal end, and the pitch of the winding structure in the braiding-winding transition zone gradually increases from the distal end to the proximal end.

[0019] Furthermore, the distal end of the braided mesh structure in the braiding-winding transition zone is tapered towards the winding structure.

[0020] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0021] The composite microguidewire provided by this invention adopts a multi-segment structure design, and optimizes mechanical properties through the synergistic effect of the inner core and the composite reinforcement layer. The inner core is divided into a support segment, a gradient segment, and a flexible tip segment. The support segment and the gradient segment are covered with a braided mesh structure, which enhances the resistance to torsional loads and provides axial support through the mesh weaving design. The flexible tip segment is covered with a spiral wound wire structure, which enhances bending flexibility through a helical winding method, making it easier to pass through tortuous blood vessels.

[0022] The composite reinforcement layer is coated with a polymer coating, which not only integrates the different structural sections but also buffers dynamic mechanical loads. This design creates an axial mechanical gradient in the composite microwire—the proximal support section uses a braided mesh structure to ensure torque transmission efficiency, while the distal winding structure enhances the flexibility of the tip, achieving a smooth transition in mechanical properties.

[0023] In summary, the composite microguidewire can reduce radial pressure in tortuous blood vessels while taking into account both proximal maneuverability and distal flexibility. It has excellent pushing performance, support and precise control capabilities, and is especially suitable for interventional procedures with complex vascular pathways. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the overall structure of the composite microguidewire in a specific embodiment of this utility model;

[0026] Figure 2 for Figure 1 Schematic diagram of the braiding-winding transition zone structure;

[0027] Figure 3 for Figure 1 Schematic diagram of the connection between the braided mesh structure and the inner core;

[0028] Among them: inner core 1, pushing section 10, supporting section 11, gradient section 12, head end soft section 13; composite reinforcement layer 2, woven mesh structure 20, winding structure 21, starting end 211, ending end 212, connection point 213; polymer coating layer 3; hydrophobic coating 4; hydrophilic coating 5. Detailed Implementation

[0029] The technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0030] The following is in conjunction with the appendix Figure 1 To be continued Figure 3 The present invention will be described in detail with reference to specific embodiments:

[0031] It should be noted that in the above and following descriptions, "proximal" usually refers to the end of the medical device that is close to the operator during normal operation, while "distal" usually refers to the end of the medical device that first enters the patient's body during normal operation.

[0032] like Figures 1 to 3As shown, this utility model provides a composite microguidewire, which is mainly used for vascular interventional therapy. It comprises:

[0033] The inner core 1 is divided into a pushing section 10, a supporting section 11, a gradient section 12 and a head-end soft section 13 along the axial direction from the proximal end to the distal end.

[0034] The composite reinforcement layer 2 includes a braided mesh structure 20 and a winding structure 21; the braided mesh structure 20 is sleeved on the support section 11 and the gradient section 12 of the inner core 1, and the winding structure 21 is wound on the soft section 13 at the head end of the inner core 1.

[0035] A polymer coating layer 3 is applied to the outer surface of the composite reinforcing layer 2. In this embodiment, the polymer coating layer 3 can be made of polyurethane, nylon, block polyether amide elastomer, polyurethane acrylate, thermoplastic polyolefin elastomer, silicone rubber, etc., preferably thermoplastic polyurethane polymer. Furthermore, the polymer coating layer 3 is bonded to the composite reinforcing layer 2 via a rheological process, resulting in good coating effect and high bonding strength.

[0036] The composite microguidewire provided by this utility model adopts a multi-segment structure design, and achieves optimized mechanical properties through the synergistic effect of the inner core 1 and the composite reinforcement layer 2. The inner core 1 is divided into a support segment 11, a gradient segment 12, and a flexible tip segment 13. The support segment 11 and the gradient segment 12 are covered with a braided mesh structure 20, which enhances the resistance to torsional loads and provides axial support through the mesh braiding design. The flexible tip segment 13 is wrapped with a wire winding structure 21, which enhances bending flexibility through a helical winding method, making it easier to pass through tortuous blood vessels.

[0037] The composite reinforcement layer 2 is covered with a polymer coating layer 3, which not only achieves the integrated structure of different sections, but also buffers dynamic mechanical loads. This design enables the composite microguidewire to form an axial mechanical gradient—the proximal support section 11 ensures torque transmission efficiency through the braided mesh structure 20, while the distal winding structure 21 improves the flexibility of the tip, achieving a smooth transition in mechanical properties.

[0038] In summary, the composite microguidewire can reduce radial pressure in tortuous blood vessels while taking into account both proximal maneuverability and distal flexibility. It has excellent pushing performance, support and precise control capabilities, and is especially suitable for interventional procedures with complex vascular pathways.

[0039] Furthermore, in some specific embodiments, the inner core 1 can be made of nickel-titanium alloy or stainless steel, with a diameter of 0.1mm to 0.5mm, and is manufactured through a grinding process to provide basic support for vascular interventional therapy. Simultaneously, the size of the inner core 1 gradually decreases from proximal to distal. When the inner core 1 is made of nickel-titanium alloy, the superelasticity of nickel-titanium causes a certain loss of torque in the inner core 1; when the inner core 1 is made of stainless steel, stainless steel can provide a more uniform torque transmission for the guidewire. The specific material selection can be made by those skilled in the art based on the actual situation.

[0040] The woven mesh structure 20 is made of stainless steel or cobalt-chromium alloy, with a weaving density of 30-120 intersections / inch, enhancing its resistance to torsional loads. Furthermore, when the weaving density exceeds 80 intersections / inch, a micron-level mesh structure can be formed, further distributing the torsional load evenly along the axial direction of the inner core 1, significantly improving its resistance to torsional loads. In addition, the elastic modulus of the cobalt-chromium alloy material can reach 230 GPa, while the elastic modulus of the stainless steel material can reach 190 GPa, effectively resisting lateral compression deformation of the blood vessel wall.

[0041] The winding structure 21 is made of platinum-tungsten or platinum-nickel alloy, and its pitch is 0.08mm to 0.2mm, which significantly improves bending flexibility. Traditional spring coil guide wires typically have a pitch ≥0.3mm, while the winding structure 21 in this invention has a pitch of 0.08mm to 0.2mm, creating an ultra-fine pitch, increasing the number of coils per unit length, and significantly improving flexibility. Of course, the winding structure 21 may also contain a platinum marking ring to enhance its developing function.

[0042] Furthermore, in some specific embodiments, the proximal end of the composite microguidewire is coated with a hydrophobic coating 4, the thickness of which is 5–15 μm. The hydrophobic coating 4 may be a polytetrafluoroethylene (PTFE) coating to reduce sliding resistance between the catheter and the guidewire. In this embodiment, the hydrophobic coating 4 is only coated on the outer surface of the inner core 1 push section 10.

[0043] The distal end of the composite microguidewire is coated with a hydrophilic coating 5, the thickness of which is 2–10 μm. The hydrophilic coating 5 can be polyvinylpyrrolidone (PVP) or a PVP coating, reducing friction when passing through narrow blood vessels. In this embodiment, the hydrophilic coating 5 is coated on the outer surface of the polymer coating layer 3.

[0044] It should be noted that in this embodiment, the hydrophobic coating 4 and the hydrophilic coating 5 are respectively attached to the outer surface of the composite microwire by dip coating or spray coating processes.

[0045] Furthermore, in some specific embodiments, the hydrophilic coating 5 can be loaded with heparin molecules. By loading heparin molecules, the hydrophilic coating 5 can simultaneously achieve hydrophilic properties and anticoagulant function.

[0046] Furthermore, in some specific embodiments, the woven mesh structure 20 is heat-set and fitted over the support section 11 and transition section 12 of the inner core 1. In this invention, the woven mesh structure 20, after heat-setting, is fitted over the support section 11 and transition section 12 of the inner core 1. It can be precisely shaped according to the geometry of the inner core 1 (such as the rigid structure of the support section 11 and the curvature change of the transition section), ensuring that the woven mesh is tightly fitted to the surface of the inner core 1, avoiding structural failure caused by deformation and misalignment during use. This is especially suitable for scenarios that require conforming to complex anatomical structures. At the same time, the support section 11 and transition section 12 of the inner core 1 perform different functions (the support section 11 provides rigid support, and the transition section 12 achieves a flexible transition). The heat-set woven mesh can be specifically matched to the mechanical characteristics of each section: the woven mesh outside the support section 11 enhances the radial support force, and the woven mesh outside the transition section 12 adapts to changes in pipe diameter through the shaped flexible structure, improving the overall structural compatibility.

[0047] Specifically, the braided mesh structure 21 includes a starting end 211 and an ending end 212. Both the starting end 211 and the ending end 212 of the braided mesh structure 21 are fixedly connected to the inner core 1 by laser welding or adhesive bonding, improving the connection strength. Simultaneously, the fixed design of both ends of the braided mesh structure 21 to the inner core 1 forms an "integrated" structure. The mesh structure of the braided mesh can disperse local stress concentration, while the inner core 1 provides axial support for the braided mesh. The synergistic effect of both improves the device's resistance to compression and radial collapse, while reducing the risk of thrombosis or device displacement due to loose connections. It should be noted that the fixed connection of the starting end 211 and the ending end 212 to the inner core 1 generally refers to the connection point 213 between the starting end 211 and the ending end 212 and the inner core 1. Figure 3 As shown.

[0048] More specifically, the distal end of the wire-wound structure 21 is fixedly connected to the inner core 1 by brazing, and the proximal end of the wire-wound structure 21 is fixedly connected to the inner core 1 by brazing or adhesive. The simultaneous fixation of the distal and proximal ends of the wire-wound structure 21 forms a "two-point anchoring" mode, which can effectively resist axial tension, radial pressure, and torsional torque. For example, in vascular interventional devices, blood flow impact or pushing operations can easily cause wire displacement; double-end fixation ensures that it always fits snugly against the inner core, avoiding device malfunction caused by structural loosening.

[0049] Brazing forms a metallurgical bond between molten filler metal and the metal surface, achieving a connection strength close to that of the base material. It is particularly suitable for elastic materials such as platinum-nickel alloys, maintaining the fatigue resistance of the wire. Distal brazing fixation can withstand repeated bending of the device tip in complex vascular pathways, preventing wire breakage. Proximal brazing or adhesive bonding is available: brazing is suitable for rigid connections to the metal core, while adhesive bonding uses an elastic medium to buffer stress, preventing damage to the flexible wire (such as nickel-titanium alloys) from the rigid connection, adapting to different material combinations.

[0050] Furthermore, in some specific embodiments, the proximal end of the winding structure 21 extends to the distal end of the braided mesh structure 20, forming a braiding-winding transition zone; the length of the braiding-winding transition zone is 10cm to 15cm, such as... Figure 2 As shown.

[0051] And / or, the braiding density of the braided mesh structure 20 in the braiding-winding transition zone gradually decreases from the proximal end to the distal end, and the pitch of the winding structure 21 in the braiding-winding transition zone gradually increases from the distal end to the proximal end.

[0052] In the braided-winding transition zone, the braided mesh structure 20 decreases in braid density from near to far (e.g., from tightly braided to loosely braided), resulting in a gradual decrease in radial support and bending stiffness. Conversely, the pitch of the winding structure 21 increases from far to near (i.e., the helical spacing increases), significantly improving flexibility. These two elements form a "gradually changing stiffness" braided-winding transition zone (10-15 cm in length), which avoids stress concentration caused by abrupt changes in stiffness in different sections.

[0053] More specifically, the distal end of the braided mesh structure 20 in the braiding-winding transition zone is tapered towards the winding structure 21. This tapering (i.e., gradually decreasing diameter) distal end of the braided mesh structure 20 geometrically matches the helical shape of the winding structure 21, avoiding stress concentration at the junction of the two structures due to abrupt changes in cross-section. Simultaneously, the tapered shape facilitates pressing it under the winding structure 21, reducing the risk of the braided mesh structure unraveling and improving feasibility in actual production.

[0054] In this invention, the composite microguidewire, during the pushing phase, utilizes the braided mesh structure 20 to efficiently transmit rotational torque, while the polymer coating layer 3 buffers longitudinal stress. During the bending phase, the winding structure 21 allows a bending radius ≤1mm, and the hydrophilic coating 5 expands upon contact with water, reducing the coefficient of friction to 0.02–0.05.

[0055] The present invention has been further described above with reference to specific embodiments. However, it should be understood that the specific description herein should not be construed as limiting the substance and scope of the present invention. Various modifications made by those skilled in the art to the above embodiments after reading this specification are all within the scope of protection of the present invention.

Claims

1. A composite microguidewire, characterized in that: It includes: The inner core is divided into a pushing section, a supporting section, a gradient section and a soft head section along the axial direction from the proximal end to the distal end. A composite reinforcement layer, comprising a woven mesh structure and a wound wire structure; the woven mesh structure is sleeved outside the support section and the gradient section of the inner core, and the wound wire structure is wound onto the soft section at the head end of the inner core. A polymer coating layer is applied to the outer surface of the composite reinforcement layer.

2. The composite microwire according to claim 1, characterized in that: The woven mesh structure is made of stainless steel or cobalt-chromium alloy.

3. The composite microwire according to claim 2, characterized in that: The weaving density of the woven mesh structure is 30 to 120 cross points per inch.

4. The composite microwire according to claim 1, characterized in that: The wire winding structure is made of platinum-tungsten or platinum-nickel alloy, and the pitch of the wire winding structure is 0.08 mm to 0.2 mm.

5. The composite microwire according to claim 1, characterized in that: The proximal end of the composite microguidewire is coated with a hydrophobic coating, the thickness of which is 5–15 μm. And / or, the distal end of the composite microguidewire is coated with a hydrophilic coating, the thickness of which is 2–10 μm.

6. The composite microwire according to claim 5, characterized in that: The hydrophilic coating is loaded with heparin molecules.

7. The composite microwire according to claim 1, characterized in that: The woven mesh structure is fitted over the support section and gradient section of the inner core through heat setting treatment, and the woven mesh structure includes a starting end and an ending end, both of which are fixedly connected to the inner core by laser welding or adhesive bonding.

8. The composite microwire according to claim 1, characterized in that: The distal end of the wire winding structure is fixedly connected to the inner core by brazing, and the proximal end of the wire winding structure is fixedly connected to the inner core by brazing or adhesive bonding.

9. The composite microwire according to claim 1, characterized in that: The near end of the winding structure extends to the far end of the braided mesh structure, forming a braiding-winding transition zone; the length of the braiding-winding transition zone is 10cm to 15cm. And / or, the braiding density of the braided mesh structure in the braiding-winding transition zone gradually decreases from the proximal end to the distal end, and the pitch of the winding structure in the braiding-winding transition zone gradually increases from the distal end to the proximal end.

10. The composite microwire according to claim 9, characterized in that: The distal end of the woven mesh structure in the braiding-winding transition zone is tapered towards the winding structure.

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