A flow-adaptive, fracture-resistant, thin-walled nerve interventional thrombolysis catheter and its fabrication method

Abstract

This invention relates to the field of neurointerventional thrombolysis catheter technology, specifically to a flow-adaptive, fracture-resistant thin-walled neurointerventional thrombolysis catheter and its manufacturing method. The catheter comprises a composite tube extending from proximal to distal. The composite tube includes inner and outer polymer coatings and a middle metal reinforcing layer. The metal reinforcing layer is a hyperelastic metal tube with a topological structure formed by laser-cut slits, providing fracture-resistant support. The laser-cut slits in the metal reinforcing layer employ a variable pitch design. This invention, by setting a continuous metal support structure around the side holes, ensures that the circumferential strength at the side holes is not lost. When the catheter is advanced in tortuous blood vessels, the axial tensile stress and radial compressive stress generated by bending are transmitted along the continuous metal skeleton, avoiding stress concentration caused by the weak structure at the side holes. This improves the lumen retention rate at the side holes, thereby reducing the risk of catheter bending in tortuous blood vessels.

Description

Technical Field

[0001] This invention relates to the field of neurointerventional thrombolysis catheter technology, specifically to a flow-adaptive, fracture-resistant thin-walled neurointerventional thrombolysis catheter and its manufacturing method. Background Technology

[0002] Acute ischemic stroke (AIS) is the leading cause of death and disability worldwide. Currently, there is an urgent clinical need for precision catheters capable of penetrating deep into the cerebral arterial and venous systems. Patent application CN202510450171.2 discloses a peripheral vascular perfusion catheter, comprising a catheter body, a tip occlusion unit, and a side-hole occlusion unit. The distal end of the catheter body is open, and the catheter body has multiple side holes. The tip occlusion unit includes an occlusion block, an abutment ring, and a spring connecting the occlusion block and the abutment ring. The side-hole occlusion unit includes a first ring, a second ring, a flexible connecting tube connecting the first and second rings, and multiple connecting rods connecting the first and second rings. The second ring is connected to a push rod via a connecting frame, and a pull rope connects the connecting frame and the occlusion block. The abutment ring, the first ring, and the second ring are all located within the catheter body. This peripheral vascular perfusion catheter exhibits excellent pushability and enables better thrombus dissolution.

[0003] Neurovascular vessels are much smaller than peripheral vessels, and neurointervention requires catheters to achieve a "thin-walled, large-lumen" design. This means maximizing the lumen within a limited vascular space to ensure adequate thrombolytic drug throughput, typically requiring a catheter wall thickness of less than 0.15 mm. However, thin walls mean lower strength, which is highly dependent on the overall structural integrity. CN202510450171.2 discloses a complex mechanical linkage structure. Multiple components must precisely coordinate and move within a catheter lumen with a diameter only on the order of millimeters or even sub-millimeters, placing extremely high demands on the machining and assembly precision of the parts. Multiple moving parts can affect the occlusion effect, increasing the risk of catheter failure during in vivo use. Furthermore, the complex internal structure encroaches on the effective drug delivery channel space of the catheter, further exacerbating the contradiction of a thin-walled, large-lumen design under the condition of a thin-walled, small-diameter catheter required for neurointervention. Summary of the Invention

[0004] In order to overcome the deficiencies in the prior art, the present invention aims to provide a flow-adaptive, fracture-resistant, thin-walled neuro-interventional thrombolysis catheter and its processing method, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, on the one hand, the present invention provides a flow-adaptive, fracture-resistant, thin-walled neuro-interventional thrombolysis catheter, comprising a composite tube extending from the proximal end to the distal end; the composite tube includes a metal reinforcing layer, which is a superelastic metal tube with a topological structure formed by laser cutting slits, used to provide fracture-resistant support; A polymer coating layer is applied to the inner and / or outer surfaces of the metal reinforcing layer. A multi-directional injection section, located in the middle and distal regions of the composite tube, includes several side holes with gradually varying diameters on the sidewall of the composite tube. These side holes are distributed with a gradually decreasing spacing along the axis of the composite tube towards the distal end, and their diameters are distributed in an increasing gradient to compensate for pressure loss along the fluid within the tube cavity. The metal reinforcing layer sidewall is provided with stress-strengthening supports corresponding to the circumferential regions of the side holes. A flow adaptive valve is fixed at the far end of the composite pipe body and is used to switch the fluid flow direction according to the pressure inside the pipe.

[0006] As a further improvement to this technical solution, the cutting trajectory of the laser-cut slit in the metal reinforcing layer is deflected or interrupted when it approaches the side hole, so as to form a continuous stress-reinforced support around the side hole.

[0007] As a further improvement to this technical solution, the aperture distribution of the side holes satisfies the following relationship:

[0008] in, Let n be the diameter of the nth side hole. The diameter of the first hole near the end. It is a compensation coefficient with a value range of 0.005 to 0.02. Let n be the axial distance from the first hole to the nth side hole. This refers to the inner diameter of the tube.

[0009] As a further improvement to this technical solution, the side holes are arranged in an arithmetic spatial spiral on the side wall of the composite tube, and the rotation angle between two adjacent side holes in the circumferential direction is 60°, so as to avoid the formation of stress concentration lines on the same cross section of the composite tube.

[0010] As a further improvement to this technical solution, the side holes are arranged in a double helix arrangement, that is, two sets of helices are symmetrically arranged in the circumference of the composite tube, the circumferential angle between adjacent side holes in each set is 120°, and the two sets are staggered by 60°.

[0011] As a further improvement to this technical solution, the flow adaptive valve is a one-way self-closing valve made of a highly elastic biocompatible material; when the injection pressure inside the composite tube is less than the preset opening pressure P of the valve, the valve is in a closed state, and the drug is sprayed laterally through several side holes; when the injection pressure is greater than the preset pressure P, the valve opens, and the drug is sprayed forward from the distal end of the composite tube; wherein the preset opening pressure P ranges from 20psi to 80psi.

[0012] As a further improvement to this technical solution, the laser-cut slits of the metal reinforcement layer adopt a variable pitch design. From the proximal end to the distal end of the composite tube, the slit pitch gradually decreases to achieve a gradient transition between the extremely high throughput performance at the distal end of the conduit and the strong support performance at the proximal end.

[0013] As a further improvement to this technical solution, the total wall thickness of the composite tube is less than 0.15 mm, and the wall thickness of the metal reinforcing layer is 0.025 mm to 0.095 mm to form a thin-walled, large-cavity shape; the material of the metal reinforcing layer is selected from one of nickel-titanium alloy, stainless steel or cobalt-chromium alloy, wherein cobalt-chromium alloy is used to obtain a thinner wall thickness and higher radioactivity.

[0014] This invention provides a method for fabricating a flow-adaptive, fracture-resistant, thin-walled neuro-interventional thrombolysis catheter, comprising the following steps: S1. Based on the preset side hole coordinates and stress distribution model, use a laser to cut a discontinuous spiral slit on the metal tube, and reserve a stress-strengthening support part that will not be cut off around the side hole coordinates. S2. A polymer material layer is coated on the inner and outer surfaces of the cut metal tube, and an integrated thin-walled tube is formed by heat shrinking or precision extrusion process, thus forming a polymer coating layer. S3. A cold laser pulse is used to perform secondary processing at the side hole coordinates determined in step S1, penetrating the polymer coating layer and the metal tube wall in one go, ensuring that the side hole is opened in the middle of the stress-strengthened support.

[0015] As a further improvement to this technical solution, the cold laser used in step S3 is a picosecond laser or a femtosecond laser with a pulse width of less than 10 picoseconds to eliminate the heat-affected zone and ensure the consistency of the side hole edge.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This flow-adaptive, fracture-resistant thin-walled neuro-interventional thrombolysis catheter and its manufacturing method utilize a continuous metal support structure around the side holes to prevent loss of circumferential strength. When the catheter is advanced through tortuous blood vessels, both the axial tensile stress and radial compressive stress generated by bending are transmitted along the continuous metal skeleton, avoiding stress concentration caused by the weak structure at the side holes. In a simulated 180° siphon segment bending test, the lumen retention rate at the side holes of this invention is more than 40% higher than that of catheters manufactured using traditional perforation techniques, reducing the risk of catheter breakage in tortuous blood vessels.

[0017] 2. This flow-adaptive, fracture-resistant, thin-walled neuro-interventional thrombolytic catheter and its manufacturing method employ a gradient orifice design with pressure compensation along the flow path. The orifice diameter increases from the proximal end to the distal end, effectively compensating for the pressure loss of thrombolytic agents within the micro-lumen. Within a working section of up to 150 mm, the flow deviation between the proximal and distal side orifices can be controlled within 10%, solving the clinical pain points of insufficient drug delivery at the distal end and incomplete thrombolysis of long thrombi in traditional thrombolytic catheters.

[0018] 3. The flow-adaptive, fracture-resistant, thin-walled neurointerventional thrombolytic catheter and its processing method: This invention uses laser cutting to form a discontinuous spiral slit and combines it with a support structure to achieve an extremely thin wall thickness while ensuring mechanical strength. This significantly increases the perfusion throughput of thrombolytic drugs, while maintaining the catheter's excellent flexibility and passage performance, meeting the clinical needs of thin-walled, large-lumen neurointerventions.

[0019] 4. The flow-adaptive anti-fracture thin-walled neuro-interventional thrombolysis catheter and its processing method. This invention integrates a pressure-adaptive valve that automatically switches the fluid flow direction according to the intraluminal pressure: under low pressure, the valve is closed and the drug solution is sprayed laterally through the side hole to achieve thrombolysis mode; under high pressure, the valve is open and the drug solution is sprayed forward through the distal end hole to achieve angiography or directional injection mode. Attached Figure Description

[0020] The accompanying drawings described herein are for illustrative purposes only. The shapes and proportions of the components in the drawings are merely schematic and intended to aid in understanding the invention. They are not intended to specifically limit the shapes and proportions of the components of the invention.

[0021] Figure 1 This is one of the cross-sectional plan views of the composite tube body of the present invention; Figure 2 This is a second sectional plan view of the composite tube body of the present invention; Figure 3 This is a schematic diagram of the composite tube body of the present invention in a state where no breakage occurs inside the blood vessel; Figure 4 A schematic diagram of the structure of the composite tube body of the present invention, which is narrowed at the head end and fitted with a variable-spacing side hole; Figure 5 A diagram showing the blood flow in the state of the composite tube body of the present invention with a narrowed head end and variable-spacing side holes; Figure 6 This is a cross-sectional plan view of the conduit for an existing product; Figure 7 This diagram illustrates the state of a catheter in an existing product breaking within a blood vessel. Figure 8 This is a schematic diagram of the blood flow in the catheter of an existing product; Figure 9 This is a schematic diagram of blood flow in the catheter of an existing product after the tip is sealed. The meanings of the labels in the diagram are as follows: 100. Composite tube body; 110. Metal reinforcing layer; 120. Polymer coating layer; 121. Injection hole; 130. Stress-reinforced support; 131. Perforation. Detailed Implementation

[0022] The specific embodiments described herein are for illustrative purposes only. Under the guidance of this invention, any possible variations of the invention by those skilled in the art should be considered within its scope. The directional terms used herein are based on the orientations shown in the accompanying drawings and are for ease of description and simplification; therefore, they should not be construed as limitations on the invention. Furthermore, in the description of this invention, "a number" means two or more, unless otherwise explicitly specified.

[0023] Please see Figures 1-5 As shown, the present invention provides a flow-adaptive, fracture-resistant, thin-walled neuro-interventional thrombolysis catheter, comprising a composite tube body 100 extending from the proximal end to the distal end; the composite tube body 100 includes an inner and outer polymer coating layer 120 and a middle metal reinforcing layer 110; the metal reinforcing layer 110 is a superelastic metal tube with a topological structure formed by laser-cut slits, used to provide fracture-resistant support; the laser-cut slits of the metal reinforcing layer 110 adopt a variable pitch design, with the slit pitch gradually decreasing from the proximal end to the distal end of the composite tube body 100, so as to achieve a gradient transition between the extremely high throughput performance at the distal end of the catheter and the strong support performance at the proximal end.

[0024] Specifically, the polymer coating layer 120 covers the inner and / or outer surfaces of the metal reinforcing layer 110; the inner layer of the composite tube 100 is preferably made of polytetrafluoroethylene (PTFE), and the outer layer is preferably made of polyether block polyamide (Pebax); the three-layer structure is integrally formed by extrusion or coating process, and the total wall thickness is controlled between 0.05 mm and 0.15 mm; the wall thickness of the metal reinforcing layer 110 is 0.025 mm to 0.095 mm to form a thin-walled, large-cavity shape; the material of the metal reinforcing layer 110 is selected from nickel-titanium alloy, stainless steel, or cobalt-chromium alloy, wherein the cobalt-chromium alloy is used to obtain a thinner wall thickness and higher radioactivity.

[0025] Specifically, the middle and distal regions of the composite tube 100 are provided with multi-directional injection sections, which include a number of side holes with gradually changing diameters on the sidewall of the composite tube 100. These side holes are distributed with gradually decreasing spacing along the axis of the composite tube 100 towards the distal end, and their diameters are distributed in an increasing gradient to compensate for pressure loss along the pipe cavity. Because the diameter of the side holes increases gradually from the proximal end to the distal end, the flow rate of the distal side holes is compensated by the increased diameter, thus achieving a uniform spray flow rate between the high-pressure, small-diameter proximal side holes and the low-pressure, large-diameter distal side holes. Figure 5 As shown, with the addition of narrowed tip and variable spacing side holes, blood flow through the side holes remains uniform and attenuated throughout the entire working section. Figures 6-9 As shown, the existing product's catheter is damaged in the blood vessel, the blood flow attenuation of the existing product's catheter, and the blood flow attenuation of the existing product's catheter after the tip is sealed.

[0026] The metal reinforcing layer 110 has stress-reinforced support portions 130 on its sidewalls and corresponding to the circumferential areas of several side holes. The cutting trajectory of the metal reinforcing layer 110 through the laser cutting slit is offset or interrupted near the side holes to form continuous stress-reinforced support portions 130 around the periphery of the side holes. The axial tensile stress (outer side of the bend) and radial compressive stress (inner side of the bend) generated by the tube body bending to conform to the blood vessel bypass the side holes and are transmitted along the continuous metal skeleton. This avoids stress concentration caused by the weak structure at the side holes of the tube body, reduces deformation at the side holes, greatly reduces the bending risk of the tube body, and ensures the passage and safety of the tube body under small bending radii.

[0027] The aperture distribution of the side holes satisfies the following relationship:

[0028] in, Let n be the diameter of the nth side hole. The diameter of the first hole near the end. It is a compensation coefficient with a value range of 0.005 to 0.02. Let n be the axial distance from the first hole to the nth side hole. The inner diameter of the catheter is denoted as k. The compensation coefficient k is preset based on parameters such as the inner diameter of the catheter, the length of the working section, and the viscosity of the thrombolytic drug. The larger the value of k, the faster the orifice increases along the flow path, and the more significant the distal flow compensation; the smaller the value of k, the smoother the orifice change. For typical applications of neurointerventional thrombolytic catheters, the preferred range of k is 0.01~0.015.

[0029] Furthermore, the side holes are arranged in an arithmetic spiral pattern on the sidewall of the composite tube 100, with the included angle of rotation between adjacent side holes in the circumferential direction being 60°, to avoid the formation of stress concentration lines on the same cross-section of the composite tube 100. This spiral arrangement also helps to distribute thrombolytic drugs more evenly within the blood vessel.

[0030] Furthermore, the side holes are arranged in a double helix pattern, that is, two sets of helices are symmetrically arranged in the 100 circumferences of the composite tube, with the circumferential angle between adjacent side holes in each set being 120°, and the two sets being staggered by 60°.

[0031] In addition, a flow adaptive valve is fixed at the distal end of the composite tube 100 to switch the fluid flow direction according to the internal pressure of the tube. The flow adaptive valve is a one-way self-closing valve made of a highly elastic biocompatible material. When the injection pressure inside the composite tube 100 is less than the preset opening pressure P of the valve, the valve is closed, and the drug is sprayed laterally through several side holes. When the injection pressure is greater than the preset pressure P, the valve opens, and the drug is sprayed forward from the distal end of the composite tube 100. The preset opening pressure P ranges from 20 psi to 80 psi.

[0032] Depending on the clinical situation, when the operator needs to perform angiography or administer a large dose of medication to target a thrombus distal to the catheter, the operator can increase the injection pressure. At this point, the valve at the catheter tip opens after the injection pressure reaches the preset pressure P. The direction of the medication flow changes from lateral to axial, moving towards the distal end of the catheter. Simultaneously, the valve can open under pressure when guidewires or other instruments pass through. After the instruments are withdrawn, the valve returns to its original position and seals the distal end due to the elasticity of the material.

[0033] It is worth noting that the flow adaptive valve can be replaced with a ball-head guidewire mating structure. Forced side spraying is achieved by mechanically blocking the end orifice with a microsphere at the tip of the microguidewire. Alternatively, the flow adaptive valve can be replaced with a tip-diameter-reducing structure. By reducing the diameter of the distal portion of the catheter, its inner diameter is matched to the outer diameter of the microcatheter, achieving the effect of forced side spraying after the microguidewire is inserted and the end orifice is blocked.

[0034] The method for fabricating the flow-adaptive, fracture-resistant, thin-walled nerve interventional thrombolysis catheter of the present invention includes the following steps: (a) Preparation of metal reinforcing layer 110 A nickel-titanium alloy tube with an outer diameter of 0.070 inches (approximately 1.78 mm) and a wall thickness of 0.050 mm was selected. A picosecond laser cutting device was used to cut the tube along a preset helical trajectory. The cutting pattern was a discontinuous helical slit, with the helical pitch gradually decreasing from 0.8 mm to 0.3 mm from the proximal end to the distal end, to achieve strong support performance at the proximal end and excellent compliance performance at the distal end. At the periphery of the preset side hole coordinates, the laser cutting trajectory was interrupted, forming a continuous metal envelope surface with a width of 0.3 mm to 0.5 mm, which is the stress-reinforced support part 130.

[0035] The side holes are positioned according to a working section length of 150mm, with a total of 15 side holes. Adjacent side holes are arranged symmetrically in a double helix pattern with a 60° rotation angle in the circumferential direction (two sets of helices are symmetrically arranged, with each set of adjacent side holes having a 120° circumferential angle). The side holes are numbered from 1 to 15 from proximal to distal, with the first proximal hole having a diameter D1 of 0.15mm, a compensation coefficient k of 0.01, and a guide tube inner diameter D of 0.60mm. The diameter of each side hole is calculated using the formula Dn = 0.15 × (1 + 0.01 × Ln / 0.60).

[0036] After laser cutting, the metal reinforcing tube is pickled to remove burrs and oxide layers.

[0037] (II) Molding of multi-layer composite tube 100 The PTFE inner liner is fitted onto the mandrel. The cut metal reinforcing tube is fitted onto the outside of the PTFE inner liner. Multiple sections of Pebax tubing with varying hardness (hardness decreasing progressively from proximal to distal) are axially connected to form an organic outer sleeve, which is then fitted onto the outside of the metal reinforcing tube. A heat-shrink tubing is fitted onto the outermost layer, and the tube is placed in an oven for heat fusion treatment at 180℃~220℃ for 5~10 minutes. After cooling, the heat-shrink tubing and mandrel are removed, resulting in an integrated three-layer composite tube body 100. The total wall thickness of the composite tube body 100 is measured to be 0.12 mm, the outer diameter to be 0.084 inches (approximately 2.13 mm), and the inner diameter to be 0.062 inches (approximately 1.57 mm).

[0038] (III) Forming of side holes A femtosecond cold laser device is used for secondary processing at the side hole coordinates determined in step (I). The laser focus is aligned with the multi-layer tube wall, penetrating the PTFE inner liner, metal reinforcement layer 110, and Pebax coating layer in one pass. The side hole is the injection hole 121 on the side wall of the polymer coating layer 120, and the side hole is the perforation 131 on the side of the stress-reinforced support 130. Since the cold laser has no heat-affected zone, the edge of the side hole is smooth, the alignment accuracy of each layer is within ±5μm, and the relative positional accuracy between the metal support island and the side hole is controlled within 0.1mm.

[0039] (iv) Installation of distal pressure control valves A duckbill-type unidirectional valve was fabricated using Pebax 3533 material via injection molding. The valve features a cross-shaped structure and a preset opening pressure P of 50 psi. The valve is fixed to the distal end of the catheter and sealed to the composite tubing 100 via heat fusion or adhesive bonding. The valve remains in a closed, sealed state under normal conditions.

[0040] Experiment 1: Bending resistance test In a simulated blood vessel model (bending angle 180°, bending radius 5mm), the catheter was pushed through the bend at a speed of 2mm / s, and the rate of change of the lumen cross-sectional area at the side hole was measured; the lumen retention rate at the side hole was improved by more than 40%.

[0041] Experiment 2: Drug administration uniformity test A simulated thrombolytic solution (with a viscosity similar to water) was used, and the flow rate at each side orifice was measured at an injection pressure of 100 psi. The test location was from the first proximal orifice to the last distal orifice. In this embodiment of the invention, the flow rate deviation between the proximal and distal ends was 7.6% ± 1.8%, improving drug delivery uniformity.

[0042] The experimental results show that, under the outer diameter specifications required for neurointervention, the present invention achieves thin-walled, large-lumen performance far superior to peripheral vascular thrombolysis catheters, increasing perfusion flux by approximately 3.3 times.

[0043] The flow-adaptive, fracture-resistant, thin-walled neurointerventional thrombolytic catheter provided by this invention features a rational structural design, feasible manufacturing process, and excellent performance indicators, making it widely applicable in the clinical thrombolytic treatment of acute ischemic stroke. This catheter can safely pass through tortuous cerebral arteries and veins while maintaining lumen integrity, achieving intelligent switching between long-range uniform drug spraying and end-to-side spraying modes, significantly improving the efficacy of thrombolytic therapy and the convenience of surgical procedures. The manufacturing method of this invention employs mature laser cutting, thermal fusion composite, and cold laser drilling processes, suitable for industrial mass production and possessing promising industrial application prospects.

[0044] It should be noted that the above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A flow-adaptive, fracture-resistant, thin-walled nerve interventional thrombolysis catheter, characterized in that: It includes a composite tube (100) extending from the proximal end to the distal end; the composite tube (100) includes a metal reinforcing layer (110), which is a superelastic metal tube with a topological structure formed by laser cutting slits, used to provide flexural support; A polymer coating layer (120) is applied to the inner and / or outer surfaces of the metal reinforcing layer (110); The multi-directional injection section, located in the middle and distal regions of the composite tube (100), includes a plurality of side holes with gradient-changing diameters on the sidewall of the composite tube (100); the plurality of side holes are distributed with gradually decreasing spacing along the axis of the composite tube (100) toward the distal end, and their diameters are distributed in an increasing gradient to compensate for the pressure loss of the fluid along the pipe cavity; the sidewall of the metal reinforcing layer (110) and the circumferential region of the plurality of side holes are respectively provided with stress-strengthening support parts (130). A flow adaptive valve is fixed at the far end of the composite pipe (100) and is used to switch the fluid flow direction according to the pressure inside the pipe.

2. The flow-adaptive, fracture-resistant, thin-walled neuro-interventional thrombolysis catheter according to claim 1, characterized in that, The metal reinforcing layer (110) is deflected or interrupted near the side hole by the cutting trajectory of the laser-cut slit, so as to form a continuous stress-reinforced support (130) around the side hole.

3. The flow-adaptive, fracture-resistant, thin-walled neuro-interventional thrombolysis catheter according to claim 2, characterized in that, The aperture distribution of the side holes satisfies the following relationship: in, Let n be the diameter of the nth side hole. The diameter of the first hole near the end. It is a compensation coefficient with a value range of 0.005 to 0.

02. Let n be the axial distance from the first hole to the nth side hole. This refers to the inner diameter of the tube.

4. The flow-adaptive, fracture-resistant, thin-walled neuro-interventional thrombolysis catheter according to claim 3, characterized in that, The side holes are arranged in an arithmetic spiral pattern on the side wall of the composite tube (100), and the rotation angle between two adjacent side holes in the circumferential direction is 60° to avoid the formation of stress concentration lines.

5. The flow-adaptive, fracture-resistant, thin-walled nerve interventional thrombolysis catheter according to claim 4, characterized in that, The side holes are arranged in a double helix pattern, that is, two sets of helices are symmetrically arranged around the composite tube (100) in the circumferential direction, with the circumferential angle between each set of adjacent side holes being 120° and the two sets being staggered by 60°.

6. The flow-adaptive, fracture-resistant, thin-walled neuro-interventional thrombolysis catheter according to claim 5, characterized in that, The flow adaptive valve is a one-way self-closing valve made of highly elastic biocompatible material; when the injection pressure inside the composite tube (100) is less than the preset opening pressure P of the valve, the valve is in a closed state and the drug is sprayed laterally through several side holes; when the injection pressure is greater than the preset pressure P, the valve opens and the drug is sprayed forward from the distal port of the composite tube (100). The preset opening pressure P ranges from 20 psi to 80 psi.

7. The flow-adaptive, fracture-resistant, thin-walled neuro-interventional thrombolysis catheter according to claim 6, characterized in that, The laser-cut slits of the metal reinforcing layer (110) are designed with variable pitch, and the slit pitch gradually decreases from the near end to the far end of the composite tube (100).

8. The flow-adaptive, fracture-resistant, thin-walled neuro-interventional thrombolysis catheter according to claim 7, characterized in that, The total wall thickness of the composite tube (100) is less than 0.15 mm, wherein the wall thickness of the metal reinforcing layer (110) is 0.025 mm to 0.095 mm to form a thin-walled, large-cavity shape; the material of the metal reinforcing layer (110) is selected from one of nickel-titanium alloy, stainless steel or cobalt-chromium alloy.

9. A method for manufacturing a flow-adaptive, fracture-resistant, thin-walled neuro-interventional thrombolysis catheter, comprising the flow-adaptive, fracture-resistant, thin-walled neuro-interventional thrombolysis catheter as described in claim 8, characterized in that... Includes the following steps: S1. Based on the preset side hole coordinates and stress distribution model, use a laser to cut a discontinuous spiral slit on the metal tube, and reserve a stress-strengthening support part (130) that will not be cut off around the side hole coordinates. S2. A polymer material layer is coated on the inner and outer surfaces of the cut metal tube, and an integrated thin-walled tube is formed by heat shrinking or precision extrusion process to form a polymer coating layer (120). S3. A cold laser pulse is used to perform secondary processing at the side hole coordinates determined in step S1, penetrating the polymer coating layer (120) and the metal tube wall in one go, ensuring that the side hole is opened in the middle of the stress-strengthened support part (130).

10. The method for fabricating the flow-adaptive, fracture-resistant, thin-walled neuro-interventional thrombolysis catheter according to claim 9, characterized in that: The cold laser used in step S3 is a picosecond laser or a femtosecond laser with a pulse width of less than 10 picoseconds to eliminate the heat-affected zone and ensure the consistency of the side hole edge.

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