Combined catheter for cerebral angiography and treatment by radial approach

Abstract

The utility model discloses a kind of cerebral angiography and treatment of radial artery approach combined catheter, belong to medical instrument technical field, the catheter includes outer sleeve and inner core pipe;The outer sleeve includes outer tube body, the inner core pipe is movably threaded in the lumen of outer sleeve, the inner core pipe includes connected proximal end tube body and distal end tube body, the distal end tube body is pre-shaped structure, the pre-shaped structure of the distal end tube body is formed by multiple arc transition sections connected head to tail, the multiple arc transition sections constitute hook shape and the head end of distal end tube body extends to the outside of hook, the length of the pre-shaped structure of the distal end tube body is 12.5-18.5cm.The utility model sets outer sleeve and inner core pipe as independent catheter, without nesting and unscrewing when operating, reduce blood vessel injury risk;Inner core pipe has stronger superselective ability, can be directly used for the superselective angiography of target blood vessel.

Description

Technical Field

[0001] This utility model relates to the field of medical device technology, and in particular to a combined catheter for cerebral angiography and treatment via the radial artery approach. Background Technology

[0002] Currently, cerebral angiography and interventional cerebrovascular treatments are still mostly performed via the femoral artery approach. Clinically, there is a lack of catheters specifically designed for cerebral angiography and treatment via the radial artery approach. In actual clinical practice, operators often use existing pre-shaped catheters for transradial target vessel selection, but the success rate is low, especially for atypical arch arteries such as type III arches and bovine arches, where transselection is extremely difficult and often fails.

[0003] In existing technologies, while conventional pre-shaped angiography catheters can easily hook onto the target vessel opening for angiography in cases of normal arch artery course, their pre-shaped tip reduces the catheter's delivery performance along the guidewire, resulting in insufficient ascending height, reduced angiographic accuracy, and the inability to directly perform treatment. A complex exchange technique is required to replace it with a therapeutic guiding catheter, increasing surgical time and the risk of complications. The exchange technique involves hooking the pre-shaped angiography catheter onto the target vessel opening, delivering the guidewire to the distal vessel, then withdrawing the pre-shaped angiography catheter and delivering a single-bend angiography catheter along the guidewire to the target location for angiography. This process requires switching between two types of catheters, significantly increasing surgical time and the risk of complications.

[0004] To address this issue, existing technologies (such as patent publication number CN215916162U) provide a nested catheter for the radial artery approach. This catheter consists of a pre-shaped inner core and an outer cannula at the tip. During use, the two must be nested together, and the connection must be unscrewed as the target vessel approaches. After removing the inner core and guidewire, the outer cannula is then manipulated to hook onto the target vessel. However, this approach has the following drawbacks: 1) The operation requires unscrewing the connection between the inner and outer tubes, which can easily cause damage to blood vessels; 2) The inner core tube and guide wire must be removed simultaneously before the outer tube can be used for superselection, which is a complicated procedure; 3) The outer tube serves as the working channel, and its performance and structure affect the operability of superselective vessels. Utility Model Content

[0005] This invention provides a combined catheter for cerebral angiography and treatment via the radial artery approach, which is simpler to operate, safer, and has stronger superselective capabilities.

[0006] To solve the above-mentioned technical problems, the technical solution proposed by this utility model is as follows: A combined catheter for cerebral angiography and treatment via the radial artery approach includes an outer cannula and an inner core tube. The outer cannula includes an outer tube body, and the inner core tube is movably inserted into the lumen of the outer cannula. The inner core tube includes a proximal tube body and a distal tube body connected together. The distal tube body has a pre-shaped structure, which is formed by multiple arc-shaped transition sections connected end to end. The multiple arc-shaped transition sections form a fishhook shape, and the tip of the distal tube body extends outward from the fishhook. The length of the pre-shaped structure of the distal tube body is 12.5-18.5 cm.

[0007] A further improvement to the above technical solution is as follows: Preferably, the distal end of the outer tube body is a pre-shaped structure, which includes a connecting bend and a horizontal part, and the included angle between the bend and the horizontal part is 120°-160°.

[0008] Preferably, the outer tube body has a three-layer tubular structure, including an inner polymer layer, a middle metal braided mesh layer, and an outer polymer layer.

[0009] Preferably, the pre-shaped structure of the distal end of the inner core tube includes a first bend, a second bend, a third bend, and a horizontal section connected in sequence. The first bend, the second bend, and the third bend are formed by one or more arc-shaped transition sections connected end to end, and the bends are connected by an arc transition. The horizontal section is connected to the proximal end of the tube.

[0010] Preferably, the axial length of the first bend is 3.6-5.5 cm, and the central angle of the arc transition portion formed by it is 0°-30°.

[0011] Preferably, the axial length of the second bend is 4.6-6.5 cm, and the central angle of the arc transition portion formed by it is 0°-45°.

[0012] Preferably, the axial length of the third bend is 4.3-6.5 cm, and the central angle of the arc transition portion formed by it is 0°-30°.

[0013] Preferably, the proximal end of the inner core tube has a three-layer tubular structure, including an inner polymer layer, a middle metal braided mesh layer, and an outer polymer layer; the distal end of the inner core tube has a single-layer polymer tubular structure.

[0014] Preferably, the hardness of the inner core tube varies from 25D to 85D from the distal end to the proximal end.

[0015] Preferably, the outer sleeve is provided with a first seat and a first strain relief sleeve, and the inner core tube includes a second seat and a second strain relief sleeve. The first seat is provided with a Luer inner cone hole at its proximal end and an anti-rotation slot for insertion and fixing with the first strain relief sleeve at its distal end. The second seat is provided with a Luer inner cone hole at its proximal end and a slot adapted to the outer diameter of the second strain relief sleeve at its distal end.

[0016] The combined catheter for cerebral angiography and treatment via the radial artery approach provided by this utility model has the following advantages compared with the prior art: (1) The combined catheter for cerebral angiography and treatment via radial artery approach of this utility model has an inner core tube as the core component for superselection. Its tip is equipped with a multi-bend pre-shaped structure optimized for radial artery approach, and the distal tube body is a single-layer structure without braided layer. It has good shape retention and can hook and superselect target blood vessels more accurately and stably, especially suitable for aberrant arch arteries.

[0017] (2) The combined catheter for cerebral angiography and treatment via the radial artery approach of this utility model has a gradual change in length and hardness of the inner and outer tubes and a unique curved design of the inner core tube. All of these fully take into account the longer path and more complex turns of the radial artery approach compared to the femoral artery approach, so that the catheter system can better adapt to the anatomical path of the radial artery-aortic arch.

[0018] (3) The combined catheter for cerebral angiography and treatment via the radial artery approach of this invention has an outer cannula primarily responsible for establishing the treatment pathway, and its large inner lumen design provides a smooth channel for the subsequent delivery of therapeutic devices such as balloons and stents; the inner core tube is primarily responsible for superselective angiography. During operation, the outer cannula provides support for the deeper insertion of the inner core tube, resulting in good system stability. If treatment is required, the outer cannula can be easily pushed to the target location along the inner core tube to establish the pathway. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the outer tube structure of this utility model.

[0020] Figure 2 This is a schematic diagram of the inner core tube structure of this utility model.

[0021] Figure 3 This is a radial sectional view of the outer casing of this utility model.

[0022] Figure 4 This is an axial sectional view of the outer sleeve of this utility model.

[0023] Figure 5 This is a radial sectional view of the inner core tube of this utility model.

[0024] Figure 6 This is an axial sectional view of the inner core tube of this utility model.

[0025] Figure 7 (a) is a schematic diagram of the superselection of the inner core tube of this utility model.

[0026] Figure 7 (b) is a schematic diagram of the outer tube of this utility model after it moves along the inner core tube.

[0027] Explanation of the labels in the diagram: 1. First seat; 2. First strain relief sleeve; 3. Outer tube body; 4. Second seat; 5. Second strain relief sleeve; 6. Proximal tube body; 7. Horizontal section; 8. Third bend section; 9. Second bend section; 10. First bend section. Detailed Implementation

[0028] The specific embodiments of this utility model are described in detail below. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of this utility model.

[0029] Figures 1 to 7 This invention illustrates one embodiment of the combined catheter for cerebral angiography and treatment via the radial artery approach, the catheter comprising a separate outer sheath and an inner core.

[0030] like Figure 1 As shown, the outer sleeve includes a first seat 1, a first strain relief sleeve 2, and an outer tube body 3. The first seat 1 is a standard Luer connector used to connect instruments such as Y valves. The first strain relief sleeve 2 is a single-lumen tubular structure, fitted at the connection between the first seat 1 and the outer tube body 3, used to release stress. The head end of the outer tube body 3 has a pre-shaped structure. In this embodiment, the axial length of the outer tube body 3 is 95cm, the inner diameter is 2.03mm, and the outer diameter is 2.36mm.

[0031] like Figure 3 , 4 As shown, in this embodiment, the outer tube body 3 is a three-layer composite tubular structure, including an inner polymer layer, a middle metal braided mesh layer, and an outer polymer layer. Figure 1 As shown, the pre-shaped structure at its head end includes a bent portion and a horizontal portion connected thereto, with an included angle A between the bent portion and the horizontal portion being 120°-160°.

[0032] The outer cannula provides support for the delivery of the inner core tube and is used to deliver other therapeutic devices during the establishment of therapeutic vascular access. The pre-molded bend at the tip of the inner core tube facilitates the overselection of irregularly shaped vessels.

[0033] like Figure 2As shown, the inner core tube includes a second connector 4, a second strain relief sleeve 5, a proximal tube body 6, and a distal tube body. The second connector 4 is a standard Luer connector used to connect syringes, etc. The second strain relief sleeve 5 is a single-lumen tubular structure made of a high-molecular polymer, used to release stress at the connection between the second connector and the tube body. The overall axial length of the inner core tube is 130 cm, the inner diameter is 1.27 mm, and the outer diameter is 1.70 mm.

[0034] In this embodiment, both the first connector 1 and the second connector 4 are injection molded from medical-grade polycarbonate (PC) material, possessing high transparency and good mechanical properties. The first connector 1 is a standard Luer connector structure, with a 6% Luer inner cone hole at its proximal end. The small end diameter of the cone hole is 2.8 mm, the large end diameter is 4.2 mm, and the taper is 1:20, used to form a sealed connection with the Luer outer cone of instruments such as Y-valve and syringe. The distal end of the first connector 1 has a cylindrical slot for insertion and fixation with the first strain release sleeve 2. The inner wall of the slot has annular protrusions and axial anti-rotation ribs, which are interference-fitted with the annular groove and positioning groove on the outer wall of the first strain release sleeve 2 to prevent relative rotation and detachment. The outer wall of the first connector 1 is integrally molded with symmetrically distributed wing-shaped handles. The surface of the wing blades has anti-slip textures to facilitate rotation and push-pull operation by the operator. The middle section of the first connector 1 has a transition channel with a gradually changing diameter. The inner wall of the channel is smooth without sharp edges to reduce the risk of blood flow turbulence and thrombosis.

[0035] The structure of the second seat 4 is basically the same as that of the first seat 1, the difference being that the proximal Luer conical bore of the second seat 4 is of standard size, but the inner diameter of its distal slot is adapted to the outer diameter of the second strain release sleeve 5. In addition, the proximal outer wall of the second seat 4 is equipped with a rotatable locking nut, the inner wall of which has a standard Luer external thread for forming a threaded locking connection with the syringe or high-pressure contrast device, preventing it from falling off during high-pressure injection. The distal outer side of the second seat 4 is equipped with an integrally formed arc-shaped finger rest with a frosted surface, facilitating stable one-handed gripping and pushing of the inner core tube by the operator. The inner cavities of both seats are smoothly transitioned to ensure that the guidewire and other instruments pass through without jamming or damage.

[0036] like Figure 5 , 6 As shown, in this embodiment, the proximal end of the inner core tube 6 has a three-layer tubular structure, including an inner polymer layer, a middle metal braided mesh layer, and an outer polymer layer. The distal end of the inner core tube has a single-layer polymer tubular structure without a braided layer. The hardness of the entire inner core tube smoothly changes from 25D to 85D from the distal end to the proximal end.

[0037] In this embodiment, the distal end of the inner core tube has a pre-shaped structure, comprising a first bend 10, a second bend 9, a third bend 8, and a horizontal section 7 connected in sequence. The first bend 10, the second bend 9, and the third bend 8 are all formed by multiple arc-shaped transition sections connected end-to-end, with smooth arc transitions between each bend. The horizontal section 7 is connected to the proximal end of the tube 6.

[0038] In this embodiment, the axial length of the first bend 10 is 3.9 cm, and the central angle of the arc transition formed by it is between 10° and 25°; the axial length of the second bend 9 is 4.9 cm, and the central angle of the arc transition formed by it is between 15° and 40°; the axial length of the third bend 8 is 4.6 cm, and the central angle of the arc transition formed by it is between 5° and 25°. The length of a single arc transition is approximately 1.5 cm. This specific size and angle design allows the inner core tube tip to flexibly adapt to the need for a reverse bend after reaching the aortic arch from the radial artery approach to select different vessels such as the left common carotid artery and the left subclavian artery. The distal end of the inner core tube is U-shaped, and the distal end of the first bend 10 is hook-shaped. The distal end of the tube ensures good compliance of the catheter during intravascular advancement, while the pre-shaped bend facilitates the selection of target vessels.

[0039] In this embodiment, the catheter starts from the opening of blood vessels such as the aortic arch, and then is pulled back or pushed so that it naturally forms a stable ring structure within a relatively spacious blood vessel such as the ascending aorta, forming a loop, in order to facilitate the selection of blood vessels with tricky angles above the aortic arch (such as the carotid artery and subclavian artery).

[0040] In this invention, the outer cannula and the inner core are two independent catheters. They can be delivered to the specific target blood vessel location for angiography using only standard procedures (no nesting or unscrewing required), making the operation simple. Both the outer and inner core have specially curved tips, allowing for direct superselection of the target blood vessel through the inner core. The pre-shaped portion of the inner core has a thicker wall than the outer cannula, resulting in stronger superselection capability; the larger inner lumen of the outer cannula facilitates smoother delivery of subsequent instruments.

[0041] This application achieves adaptive support for complex anatomical structures through the following design: (1) Inner core tube: Made of a soft and highly malleable polymer material, the hardness of which gradually increases from the distal end (25D) to the proximal end (85D) (25D is a very soft Shore hardness, similar to soft silicone; 85D is a medium hardness, similar to a relatively hard plastic tube). The distal end is extremely soft and can conform to every bend of the blood vessel; the proximal end is slightly harder, which facilitates the transmission of pushing force.

[0042] (2) The U-shaped structure at the distal end of the inner core tube: formed by a pre-shaping process, including multiple bends (first bend, second bend, and third bend). The central angle and length of these bends are optimized so that the U-shaped structure can stably fit the opening and proximal course of the target branch blood vessel (such as the common carotid artery and vertebral artery).

[0043] (3) Outer tube: The hardness is greater than that of the inner core tube, but its far end has only a simple bend (first included angle 120°~160°), and it is not required to be independently anchored. It is only used to improve the passability when following along the inner core tube.

[0044] like Figure 7 As shown, the combined catheter for cerebral angiography and treatment via the radial artery approach of this utility model is used in the following steps: S1. First, a radial artery access is established using percutaneous puncture technique, and a 0.035-inch guidewire is inserted.

[0045] S2, along the guidewire, first insert the outer cannula into the blood vessel. Push, pull, and rotate the tip of the outer cannula (3) to the vicinity of the aortic arch (at this point, the inner cannula is not yet in use). At this stage, the distal end of the outer cannula has not yet entered the target vessel. The bend in the outer cannula helps it pass through the radial-subclavian artery junction, reducing vascular injury.

[0046] Connect the first port 1 of the outer cannula to the Y valve. Insert the guidewire again through the Y valve, and then guide the inner core tube through the Y valve and the lumen of the outer cannula into the blood vessel along the guidewire. After the inner core tube is inserted through the outer cannula and its distal end protrudes from the outer cannula, proceed towards the target branch vessel (such as the left common carotid artery) under the guidance of the guidewire.

[0047] Because the inner core tube is made of a flexible material with a pre-shaped U-shape, it naturally springs open and conforms to the direction of the blood vessel when it approaches the branch vessel opening. Supported by the outer tube, precise manipulations such as pushing, pulling, and rotating allow the distal end of the inner core tube to enter the branch vessel and be pushed to the ideal depth (usually the straight section of the vessel, about 2-3 cm). At this point, the pre-shaped bends (first, second, and third bends) of the distal end of the inner core tube precisely hook and selectively enter the target vessel, while the tube itself conforms to the vessel wall along the way, forming a stable anchor.

[0048] When using it, rotate it slightly (usually 10-15° each time) according to the opening position shown on the angiography, and gently push or pull back the inner core tube to make the opening at the tip of the inner core tube accurately aligned with the opening of the vessel to be selected, so that the inner core tube can be smoothly inserted into the vessel to be selected.

[0049] S3. After the inner core tube is in place, a contrast agent is injected through the inner core tube to perform highly selective angiography.

[0050] Keeping the inner cannula stationary, push the outer cannula along it. As the outer cannula advances, its bends help it navigate bends such as the aortic arch. Simultaneously, the inner cannula acts as a positioning support under the hooking and clamping forces of the vessel. The outer cannula moves along the inner cannula, which acts as a guide, accurately leading the outer cannula into the branch vessel. When the distal end of the outer cannula reaches near the opening of the target vessel, stop pushing, establishing a treatment pathway. At this point, the inner cannula remains in place, providing continuous support.

[0051] S4, withdraw the inner core tube and guidewire, leaving the outer cannula inside the target blood vessel as a delivery channel for subsequent treatment devices (such as stents, balloons, coils, etc.).

[0052] Throughout the process, the inner core tube remained stable, and the outer tube followed smoothly, eliminating the risk of the inner core tube slipping out. This procedure has been fully disclosed in the specification of this application and can be performed by those skilled in the art based on common sense and conventional interventional techniques.

[0053] The present invention relates to a combined catheter for cerebral angiography and treatment via the radial artery approach. The principle by which the inner core tube establishes stable support within the blood vessel is based on the following three levels: (1) Remote anchoring effect When the U-shaped structure at the distal end of the inner tube is pushed to the target branch vessel (e.g., the common carotid artery), the branch vessel's diameter is typically smaller than the inner tube's outer diameter (1.60-1.80 mm, while the common carotid artery's diameter is approximately 6-8 mm, though the branch vessel's initiation is often narrower), and the U-shaped structure is curved within the vessel, its outer side tightly adheres to the inner side of the vessel wall. The first bend 10 at the distal end of the inner tube forms a hook, making this adhesion particularly pronounced at the vessel bifurcation point, where the inner tube is secured at the branch vessel's initiation, forming a stable anchor point. Even though the inner tube is made of a soft material, its large contact area with the vessel wall (the U-shaped structure provides multiple contact points) provides sufficient friction to resist axial displacement.

[0054] The structure of the distal tube is rigorously designed. In order to provide support for the inner core tube, the dimensions and angles of each bend are designed and verified to ensure that the inner core tube can provide support for the movement of the outer tube.

[0055] (2) Fitting support along the way Throughout its path from the puncture point (radial artery) to the target vessel, the inner core of the cannula, due to its soft material, passively conforms to the natural shape of the vessel (such as the curvature of the radial artery, the bend of the subclavian artery, and the arc of the aortic arch). Therefore, the inner core is not suspended in the center of the vessel, but rather naturally rests against one side of the vessel wall (usually the lateral side), forming continuous "line contact" or even "surface contact." The total frictional force generated by this conformation along the route is far greater than the force of a single-point support, effectively preventing the inner core from slipping out entirely.

[0056] (3) Elastic constraint of blood vessel wall Human blood vessels are elastic biological tissues. When the inner tube is inserted, the vessel wall slightly expands, generating a radial elastic recoil force. This force acts perpendicularly on the surface of the inner tube, transforming into normal pressure between the inner tube and the vessel wall. According to the law of friction, friction force = coefficient of friction × normal pressure. Therefore, the elastic contraction of the vessel wall provides a natural clamping force for the inner tube. The softer the inner tube, the better it conforms to the shape of the vessel wall, the tighter the contact, the more uniform the distribution of normal pressure, and the higher the stability.

[0057] In clinical practice, the outer cannula needs to be advanced along the inner core cannula to the target vessel. During this process, the inner core cannula will not slip off due to the outer cannula, for the following reasons: (1) Direction of force: When the outer tube is pushed forward along the inner tube, the frictional force generated on the inner tube is forward (i.e., the same as the pushing direction). This force will not pull the inner tube backward, but will help to press the inner tube more tightly against the blood vessel wall (similar to pushing a soft tube forward on an object that has been inserted into a gap; the object will only become tighter and will not move backward).

[0058] (2) Radial compression is unrelated to axial slippage: At the bend of the blood vessel, the outer tube may compress the inner tube, but this compression is radial (perpendicular to the vessel wall) and does not generate axial tension. If the inner tube is to slip, it needs to overcome axial friction, while radial compression increases the positive pressure, thereby increasing friction and making the inner tube more stable.

[0059] (3) Size matching between the outer tube and the inner tube: The inner diameter of the outer tube (1.93~2.13mm) is slightly larger than the outer diameter of the inner tube (1.60~1.80mm), and there is a gap between them. This means that when the outer tube is pushed, its tip may directly contact the vessel wall (especially at bends) rather than being completely pressed against the inner tube. Therefore, the radial force that the inner tube can withstand is limited.

[0060] (4) Guidewire-assisted stabilization: During the operation, the guidewire always runs through the inner core tube, increasing the overall rigidity of the inner core tube. At the same time, the presence of the guidewire also prevents the inner core tube from bending or twisting excessively. When further stabilization of the inner core tube is required, the guidewire can be gently pushed to allow the distal end of the inner core tube to penetrate deeper into the branch vessel, thereby enhancing anchoring.

[0061] The above embodiments are merely preferred embodiments of this utility model and are not intended to limit the utility model in any way. Although this utility model has been disclosed above with reference to preferred embodiments, it is not intended to limit the utility model. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this utility model without departing from the scope of the utility model's technical solution should fall within the protection scope of this utility model's technical solution.

Claims

1. A combined catheter for cerebral angiography and treatment via the radial artery approach, characterized in that, It includes an outer tube and an inner core tube; the outer tube includes an outer tube body, and the inner core tube is movably inserted into the lumen of the outer tube. The inner core tube includes a connected proximal tube body and a distal tube body. The distal tube body is a pre-shaped structure, which is formed by multiple arc-shaped transition sections connected end to end. The multiple arc-shaped transition sections form a fishhook shape, and the head end of the distal tube body extends outward from the fishhook. The length of the pre-shaped structure of the distal tube body is 12.5-18.5 cm.

2. The combined catheter for cerebral angiography and treatment via the radial artery approach according to claim 1, characterized in that, The pre-shaped structure of the outer tube body includes a connected bent portion and a horizontal portion, and the included angle between the bent portion and the horizontal portion is 120°-160°.

3. The combined catheter for cerebral angiography and treatment via the radial artery approach according to claim 1, characterized in that, The outer tube body has a three-layer tubular structure, including an inner polymer layer, a middle metal braided mesh layer, and an outer polymer layer.

4. The combined catheter for cerebral angiography and treatment via the radial artery approach according to claim 1, characterized in that, The pre-shaped structure of the distal end of the inner core tube includes a first bend, a second bend, a third bend, and a horizontal section connected in sequence. The first bend, the second bend, and the third bend are formed by one or more arc-shaped transition sections connected end to end, and the bends are connected by a circular arc transition. The horizontal section is connected to the proximal end of the tube.

5. The combined catheter for cerebral angiography and treatment via the radial artery approach according to claim 4, characterized in that, The axial length of the first bend is 3.6-5.5cm, and the central angle of the arc transition portion formed by it is 0°-30°.

6. The combined catheter for cerebral angiography and treatment via the radial artery approach according to claim 4, characterized in that, The axial length of the second bend is 4.6-6.5cm, and the central angle of the arc transition section formed by it is 0°-45°.

7. The combined catheter for cerebral angiography and treatment via the radial artery approach according to claim 4, characterized in that, The axial length of the third bend is 4.3-6.5cm, and the central angle of the arc transition section formed by it is 0°-30°.

8. The combined catheter for cerebral angiography and treatment via the radial artery approach according to claim 4, characterized in that, The proximal end of the inner core tube has a three-layer tubular structure, including an inner polymer layer, a middle metal braided mesh layer, and an outer polymer layer; the distal end of the inner core tube has a single-layer polymer tubular structure.

9. The combined catheter for cerebral angiography and treatment via the radial artery approach according to claim 4, characterized in that, The hardness of the inner core tube varies from 25D to 85D from the distal end to the proximal end.

10. The combined catheter for cerebral angiography and treatment via the radial artery approach according to claim 4, characterized in that, The outer sleeve is provided with a first seat and a first strain relief sleeve, and the inner core tube includes a second seat and a second strain relief sleeve. The first seat has a Luer inner cone hole at its proximal end and an anti-rotation slot at its distal end for insertion and fixation with the first strain relief sleeve. The second seat has a Luer inner cone hole at its proximal end and a slot at its distal end that is adapted to the outer diameter of the second strain relief sleeve.

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