Laminar flow resistant microcatheter

Abstract

The utility model provides an anti-laminar flow microcatheter which sequentially comprises a conveying section, a side opening section and a tail end section from the near end to the far end, and the length of the tail end section is 4 mm or above; the microcatheter is provided with an inner cavity, the outer diameter of the conveying section and the tail end section ranges from 1.5 F to 4 F, and the inner diameter of the conveying section and the tail end section ranges from 0.40 mm to 1.2 mm. The side opening section is provided with more than six side openings, the distance between every two adjacent side openings ranges from 2.0 mm to 2.4 mm, the included angle between every two adjacent side openings and the axis is larger than or equal to 45 degrees and smaller than or equal to 90 degrees, the area of each side opening is 0.01 mm2 to 0.1 mm2 independently, and the areas of the side openings are sequentially increased from the near end to the far end. When the micro catheter is used for local administration, the amount of medicine mixed in all directions of blood can be uniform, all blood vessel branches can obtain proper medicine supply, and therefore the comprehensive and uniform administration effect can be achieved.

Description

Technical Field

[0001] The utility model relates to the field of medical technology, in particular to an anti-laminar flow micro-catheter and a medical device containing the micro-catheter. Background Art

[0002] Local drug delivery to human coronary arteries, head, liver and other areas can improve treatment efficiency, solve the problem of drug damage in non-drug areas caused by conventional drug delivery, and avoid the adverse effects of excessive drug delivery. In the prior art, there is a microcatheter with an opening section that allows the drug solution to flow out from the side of the catheter to reach the target area to achieve local drug delivery, which can achieve local drug delivery to a certain extent. However, since the blood in the main branch artery of the human body reaches the target area after being shunted through multiple branch vessels, the local drug delivery device placed in the main branch vessel or branch vessel in the prior art still has the problem that the drug cannot be dispersed in the blood vessel and fully mixed with the blood, resulting in the drug being unable to fully enter the vascular network of the target drug delivery area, thereby greatly reducing the effect of local drug delivery. A major challenge encountered during arterial drug delivery is that due to the laminar flow characteristics of arterial blood flow, the drug cannot be fully mixed after delivery, and then flows away along the branch vessels, affecting the drug delivery effect. For example, when using a microcatheter for contrast agent push injection, the laminar flow characteristics of the blood flow can be clearly observed, and the contrast agent flows along the branch, showing super selectivity. This leads to a key question: how to achieve uniform drug delivery to the target area under conventional microcatheter drug delivery. Therefore, there is a need for a device that can deliver global drug to a local target administration area. Utility Model Content

[0003] The utility model provides a laminar flow-resistant microcatheter, which includes the following embodiments:

[0004] Embodiment 1: A laminar flow-resistant microcatheter, which comprises, from the proximal end to the distal end, a delivery section, a side opening section, and a terminal section, wherein the length of the terminal section is greater than 4 mm;

[0005] The microcatheter has an inner lumen, and the outer diameter of the delivery section and the terminal section is 1.5F to 4F, and the inner diameter is 0.40mm to 1.2mm;

[0006] The side opening section is provided with more than 6 side openings, wherein the distance between adjacent side openings is 1.8 to 3 mm, and the angle relative to the axis is greater than or equal to 45° and less than or equal to 90°, or greater than or equal to 60° and less than or equal to 80°, and the area of ​​each side opening is independently 0.01 mm 2 To 0.1mm 2 , and the area of ​​the side opening increases from the proximal end to the distal end.

[0007] Embodiment 2. The anti-laminar flow microcatheter according to Embodiment 1, wherein the length of the distal segment is 6 mm or more, 8 mm or more, 10 mm or more, 12 mm or more, or 20 mm or more.

[0008] Embodiment 3. The anti-laminar flow microcatheter according to Embodiment 1, wherein the side opening segment is directly connected to the distal segment.

[0009] Embodiment 4. The anti-laminar flow microcatheter according to Embodiment 1, wherein a radiopaque marker is provided at at least one of the following positions: 1-4 mm from the most distal end of the microcatheter, 1-4 mm from the distal end of the side opening segment, and 1-4 mm from the proximal end of the side opening segment.

[0010] Embodiment 5. The anti-laminar flow microcatheter according to Embodiment 1, wherein the distance between adjacent side openings is 1.9 to 2.5 mm, such as 2.0 to 2.4 mm, such as 2.1 to 2.3 mm, and the angle with respect to the axis is greater than or equal to 65° and less than or equal to 78°, and the area of each side opening is independently 0.015 mm 2 to 0.08 mm 2 。

[0011] Embodiment 6. The anti-laminar flow microcatheter according to Embodiment 1, wherein the side opening segment is provided with 7 to 10 side openings.

[0012] Embodiment 7. The anti-laminar flow microcatheter according to Embodiment 1, wherein the outer surface of the microcatheter is provided with an anticoagulant coating, such as a heparin coating, a heparinoid coating, an MPC copolymer, etc., and optionally both the inner and outer surfaces of the microcatheter are provided with an anticoagulant coating.

[0013] Embodiment 8. The anti-laminar flow microcatheter according to Embodiment 1, wherein the length of the delivery segment is 0.4 to 1.5 m, 0.8 to 1.3 m, or 1.1 to 1.3 m.

[0014] Embodiment 9. The anti-laminar flow microcatheter according to Embodiment 1, wherein the microcatheter has an inner layer and an outer layer, wherein the inner layer is made of polytetrafluoroethylene (PTFE), and the outer layer is made of the following materials: polyether block polyamide (pebax), nylon, or a combination thereof, and optionally a braided layer is provided between the inner layer and the outer layer.

[0015] Embodiment 10. The anti-laminar flow microcatheter according to Embodiment 9, wherein the braided layer is provided in the delivery segment, so that the delivery segment is shapeable.

[0016] Embodiment 11. The anti-laminar flow microcatheter according to Embodiment 9, wherein the end segment and the side opening segment are not provided with a braided layer, so that the catheter is relatively soft.

[0017] Embodiment 12. The anti-laminar flow microcatheter according to Embodiment 1, wherein the inner cavity is through or non-through, the delivery segment is not provided with side openings, and the end segment is substantially straight.

[0018] When local drug administration is performed using the microcatheter described in the present application, the drug exits through the side openings, and the liquid output between the side holes in all directions is relatively close, so that the amount of drug mixed in the blood in the blood vessel in all directions is relatively uniform, and all blood vessel branches can obtain appropriate drug supply, and a comprehensive and uniform drug administration effect can be achieved. Even if there is wall attachment, offset, or bending in a certain direction in the side opening segment, the drug administration effect will not be affected. Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings described below only relate to some embodiments of the present disclosure and do not limit the present disclosure.

[0020] Figure 1 Schematic diagram of the anti-laminar flow microcatheter described in Embodiment 1;

[0021] Figure 2 Schematic diagram of the side opening segment described in Embodiment 1;

[0022] Figure 3 Schematic diagram of the drug liquid mixing state and distribution in each pipeline under the wall-attached state of the microcatheter described in the present application;

[0023] Figure 4 Schematic diagram of the drug liquid mixing state and distribution in each pipeline under the wall-attached state of the microcatheter of Control 1;

[0024] Figure 5 Schematic diagram of the angle between adjacent side openings relative to the axis.

[0025] Reference Signs:

[0026] 100 - side opening segment, 200 - end segment, 300 - delivery segment, 10 - inner cavity, 110 - side opening. Detailed Embodiments

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present disclosure. Apparently, the described embodiments are only a part rather than all of the embodiments of the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present disclosure without creative efforts shall fall within the scope of protection of the present disclosure.

[0028] On the one hand, the present application discloses a laminar flow-resistant microcatheter, which sequentially includes from proximal to distal: a delivery section, a side-opening section, and a terminal section, where the length of the terminal section is 4 mm or more; the microcatheter has a lumen, and the outer diameters of the delivery section and the terminal section are 1.5F to 4F, and the inner diameters are 0.40 mm to 1.2 mm; the side-opening section is provided with more than 6 side openings, where the distance between adjacent side openings is 1.8 to 3 mm, and the angle relative to the axis is greater than or equal to 45° and less than or equal to 90°, or greater than or equal to 60° and less than or equal to 80°, and the area of each side opening is independently 0.01 mm 2 to 0.1 mm 2 , and the areas of the side openings gradually increase from proximal to distal.

[0029] In the present application, the angle between adjacent side openings relative to the axis refers to the angle between the projection points of two adjacent side openings relative to the axis projection point in the projection plane along the axis direction of the microcatheter. Attached Figure 5 Briefly shows a schematic diagram of this angle. In the figure, a and b on the left are two adjacent side openings, the dotted line is the axis of the microcatheter, the circle on the right is the projection plane along the axis direction of the microcatheter. In this projection plane, point o is the axis projection point, that is, the center of the circle, and points a and b are the projection points of the two adjacent side openings in the projection plane along the axis direction of the microcatheter, and the angle ω between oa and ob is the angle between adjacent side openings relative to the axis.

[0030] The present application defines the angle between adjacent side openings relative to the axis to be greater than or equal to 45° and less than or equal to 90°, or greater than or equal to 60° and less than or equal to 80°, so as to ensure that the side openings are generally spirally distributed along the outer periphery of the microcatheter. For example, when the angle is set to 45°, setting 8 side openings can make the side openings rotate one week along the outer periphery of the microcatheter. When the angle is set to 90°, setting 4 side openings can make the side openings rotate one week along the outer periphery of the microcatheter, so that the microcatheter can discharge liquid along 360°.

[0031] When administering drugs through a microcatheter, the drugs flow out from the inner cavity of the microcatheter through the side openings into the blood and reach the target area with the blood flow. The present application stipulates that the area of ​​the side openings increases from the proximal end to the distal end, so that the amount of liquid outflow from the side openings is relatively close, so that the amount of drugs mixed in all directions of the blood in the blood vessels is relatively uniform, all blood vessel tributaries can obtain appropriate drug supply, and a comprehensive and uniform drug administration effect can be achieved. Even if the side opening section is attached to the wall, offset, or bent in a certain direction, it will not affect the drug administration effect.

[0032] When using a microcatheter for local drug delivery, it is very easy to produce uneven drug delivery at the branch blood vessel shunt, for example, most of the drug solution enters some branch blood vessels, or the drug solution is mainly transported along the main branch blood vessels, which significantly reduces the effect of local drug delivery. The applicant found that an important reason for this phenomenon is that the blood in the arterial blood vessels is in laminar flow as the main flow state, which makes the drug solution unable to fully mix with the blood in the blood vessels along all directions perpendicular to the blood flow. Even if the drug solution enters the blood in a certain direction perpendicular to the blood flow direction, it is very easy for the laminar flow of the blood to prevent the drug solution from fully mixing with the blood and affect the effect of local drug delivery. Therefore, how to locally inhibit the laminar flow of blood in the drug delivery area of ​​the artery so that the microcatheter can achieve the "anti-laminar flow" effect is the key to improving the uniform drug delivery in the local area. Since the side openings of the present application are distributed in all directions along the periphery of the microcatheter, when the liquid output of the side openings in each direction is relatively close, a good "anti-laminar flow" effect can be achieved, and the amount of mixed drugs in all directions is relatively uniform. The present application achieves an anti-laminar flow effect by setting side openings whose areas gradually increase from the proximal end to the distal end, improving the laminar flow effect of blood in local drug delivery, thereby achieving a local, comprehensive and uniform drug delivery effect, which helps to improve the effect of local treatment, especially for the treatment of local tumors or specific organs. The anti-laminar flow microcatheter of the present application can achieve 360° uniform liquid output, and can still achieve an anti-laminar flow effect even in the case of catheter deviation, wall adhesion, bending, etc.

[0033] In the present application, for the side opening section, the proximal end refers to the side of the side opening section close to the conveying section, and the distal end refers to the side of the side opening section close to the terminal section. The present application has no specific restrictions on the shape of the side opening, which can be circular, nearly circular, elliptical or other shapes, as long as its area meets the requirements.

[0034] In some embodiments, the outer diameter of the side opening section is 1.5F to 4F, and the diameter of the side opening located at the farthest end is less than half of the outer diameter of the side opening section.

[0035] In some embodiments, the length of the distal segment is 6 mm or more, 8 mm or more, 10 mm or more, 12 mm or more, or 20 mm or more. When the distal segment is relatively long, more drugs or even all of the drugs are mixed into the blood from the side openings, overcoming the uneven blood mixing caused by laminar flow. At the same time, the relatively long distal segment can fluctuate with the blood flow, further suppressing the blood laminar flow, thereby further achieving uniform and sufficient mixing of the liquid medicine.

[0036] In some embodiments, the side opening segment is directly connected to the distal segment.

[0037] In some embodiments, the anti-laminar flow microcatheter is provided with a radiopaque marker at at least one of the following positions, such as a radiopaque marker made of materials such as platinum-iridium, tungsten, barium sulfate, etc.: at a distance of 1-4 mm from the most distal end of the microcatheter, at a distance of 1-4 mm from the distal end of the side opening segment, and at a distance of 1-4 mm from the proximal end of the side opening segment. Preferably, the radiopaque marker is a radiopaque ring, such as a platinum ring.

[0038] In some embodiments, the distance between adjacent side openings is 1.9 to 2.5 mm, such as 2.0 to 2.4 mm, such as 2.1 to 2.3 mm. In some embodiments, the angle between adjacent side openings with respect to the axis is greater than or equal to 65° and less than or equal to 78°, and the area of each side opening is independently 0.015 mm 2 to 0.08 mm 2 . In some embodiments, the distance between adjacent side openings is 1.9 to 2.5 mm, and the angle with respect to the axis is greater than or equal to 65° and less than or equal to 78°, and the area of each side opening is independently 0.015 mm 2 to 0.08 mm 2 .

[0039] The applicant has found that if the opening distance is too small, the strength of the microcatheter cannot meet the requirements. An appropriate opening distance can not only meet the strength requirements but also achieve a good local anti-laminar flow effect.

[0040] In some embodiments, the side opening segment is provided with 7 to 10 side openings.

[0041] In some embodiments, the outer surface of the microcatheter is provided with an anticoagulant coating, and the anticoagulant coating is a heparin coating or a heparin-like coating or an MPC copolymer, etc. Optionally, both the inner and outer surfaces of the microcatheter are provided with anticoagulant coatings.

[0042] In some embodiments, the length of the delivery segment is 0.4 to 1.5 m, 0.8 to 1.3 m, or 1.1 to 1.3 m.

[0043] In some embodiments, the microcatheter has an inner layer and an outer layer, wherein the inner layer is made of polytetrafluoroethylene (PTFE), and the outer layer is made of polyether block polyamide (pebax) / nylon. Optionally, a braided layer is disposed between the inner layer and the outer layer. Preferably, the braided layer is only disposed in the delivery section.

[0044] In some embodiments, the microcatheter has an inner layer and an outer layer. The proximal end of the outer layer is made of nylon 12, and the distal end is made of polyether block polyamide (pebax).

[0045] In some embodiments, the braided layer is disposed in the delivery section, such that the delivery section is shapeable. Before treatment, the delivery section is set to an appropriate shape to facilitate forming a suitable fixing relationship with the blood vessel, indirectly fixing the side opening section, which is beneficial for fixing the side opening section at a designated position for drug delivery.

[0046] In some embodiments, the terminal section and the side opening section are not provided with a braided layer, such that the catheter is relatively soft. The soft terminal section and side opening section can float in the blood, increasing the turbulent flow situation and reducing the occurrence of laminar flow.

[0047] In some embodiments, the inner cavity is through or non-through, the delivery section is not provided with side openings, and the terminal section is substantially straight.

[0048] Since the side openings of the present application are distributed in all directions along the outer periphery of the microcatheter, when the liquid output of the side openings in each direction is relatively close, a good "anti-laminar flow" effect can be achieved, and the amount of the drug mixed in each direction is relatively uniform. By providing side openings with areas gradually increasing from the proximal end to the distal end, the present application achieves the anti-laminar flow effect, improves the laminar flow effect of blood in local drug delivery, thereby realizing the local overall uniform drug delivery effect, which helps to improve the effect of local treatment, especially for the treatment of local tumors or specific organs. The anti-laminar flow microcatheter of the present application can achieve 360° uniform liquid output, and can still achieve the anti-laminar flow effect even in the cases of catheter offset, wall attachment, bending, etc.

[0049] Examples

[0050] Example 1

[0051] This example discloses an anti-laminar flow microcatheter, as Figure 1 shown. It sequentially includes from the proximal end to the distal end: a delivery section 300, a side opening section 100, and a terminal section 200. The length of the terminal section is 12 mm, the length of the side opening section is 22 mm, and the length of the delivery section is 1 m. The microcatheter has an inner cavity 10. The outer diameter of the delivery section and the terminal section is 2.2F, and the inner diameter is 0.43 mm. The side opening section is directly connected to the terminal section. The side opening section is provided with 8 side openings 110.Figure 2 Schematic diagram of the side opening section 100, showing the distribution and dimensions of 8 side openings in the figure. The side openings shown by the dashed lines in the figure are the side openings located on the back of the microcatheter. The distance between adjacent side openings is 2.1 mm (this distance is the horizontal distance along the axis of the microcatheter), and the angle relative to the axis is 60°. The shape of the side openings is nearly circular side openings. The diameters of the side openings from the proximal end to the distal end are 0.15 mm, 0.17 mm, 0.19 mm, 0.21 mm, 0.23 mm, 0.25 mm, 0.27 mm, 0.29 mm in sequence. The opening areas of the side openings are 0.018 mm 2 , 0.023 mm 2 , 0.028 mm 2 , 0.035 mm 2 , 0.042 mm 2 , 0.049 mm 2 , 0.057 mm 2 , 0.066 mm 2 , that is, the area of the side openings gradually increases from the proximal end to the distal end.

[0052] In this embodiment, the side openings are generally spirally distributed along the outer periphery of the microcatheter, and the angle between adjacent side openings relative to the axis is 60°. Therefore, 6 side openings can rotate around the outer periphery of the microcatheter for one week, so that the microcatheter can discharge liquid along 360°.

[0053] When using the microcatheter described in the present application for local drug delivery, the drug passes through the inner cavity of the microcatheter and discharges liquid through the side openings. The liquid discharge amounts between the side openings in all directions are relatively close, making the drug amounts mixed in the blood in all directions in the blood vessel relatively uniform. All blood vessel branches can obtain appropriate drug supply, and a comprehensive and uniform drug delivery effect can be achieved. Even if there is wall attachment, offset or bending in a certain direction in the side opening section, it will not affect the drug delivery effect.

[0054] Example 2

[0055] This embodiment discloses an anti-laminar flow microcatheter, which is basically the same as Example 1, except that the length of the end section is 4 mm.

[0056] Example 3

[0057] This embodiment discloses an anti-laminar flow microcatheter, which is basically the same as Example 1, except that the length of the end section is 4 mm, and the side opening section is provided with 10 side openings.

[0058] Example 4

[0059] This embodiment discloses a laminar flow-resistant microcatheter, which is basically the same as Embodiment 1, except that the length of the end segment is 20 mm, the side opening segment is provided with 4 side openings, and the angle between adjacent side openings with respect to the axis is 90°.

[0060] Control experiment

[0061] The following microcatheters for local drug delivery are set in this application as controls:

[0062] Control 1: A microcatheter without side openings, and the liquid medicine flows out through the distal opening, and its dimensions are the same as those in Embodiment 1;

[0063] Control 2: Side holes are provided, and the dimensions and the number and size of the side holes of the microcatheter are the same as those in Embodiment 1, but the side holes are distributed on one side of the microcatheter and are all distributed on the same straight line;

[0064] Control 3: Side holes are provided, and the dimensions, the number and the distribution of the side holes of the microcatheter are the same as those in Embodiment 1, but the sizes of the side holes are the same, and the diameter is 0.22 mm.

[0065] Observation of liquid outflow state

[0066] Place the microcatheter in a water tank, and conduct a simulation test with red ink (density 0.989 g / ml) close to the density of the chemotherapeutic drug (0.8 - 1.2 g / ml). The measured viscosity is 1 mPa·s. Input the red ink into the microcatheter at the infusion rates of 0.870 ml / min and 1.740 ml / min respectively, observe the liquid outflow situation of the ink in the microcatheter flowing out through the side openings and / or the distal opening into the water, and record the amount of liquid flowing out from the distal end and the side holes respectively.

[0067] Observe the liquid outflow situation of the microcatheters described in Embodiment 1 and Embodiment 2 at the infusion rate of 1.740 ml / min. The observation results are shown in the following table:

[0068] Table 1 Observation of liquid outflow state

[0069]

[0070]

[0071] Observation of laminar flow resistance effect

[0072] Place the microcatheter in the flow channel of the simulated blood vessel. The flow channel has two branch pipelines and a colorless fluid flowing in a state simulating blood flow. Place the side opening segment of the microcatheter in the main pipeline upstream of the branch pipeline.

[0073] Red ink (density 0.989 g / ml, measured viscosity 1 mPa·s) with a density close to that of chemotherapeutic drugs (0.8 - 1.2 g / ml) was used to simulate the liquid medicine for simulation tests. The red ink was input into the microcatheter at infusion rates of 0.870 ml / min and 1.740 ml / min respectively. By observing the outflow distribution state of the ink in the flow channel, the streamline, and the color of the liquid flowing out of each outlet, the anti-laminar flow effect of the microcatheter was judged. And by comparing the colors of the liquid flowing out of 1 main branch pipeline outlet and 2 branch pipeline outlets, the mixing uniformity of the simulated liquid medicine was judged.

[0074] Figure 3 and Figure 4 are respectively schematic diagrams of the liquid medicine mixing state and its distribution in each pipeline when the microcatheter is in the wall-attached state in the examples and Control 1. The dotted arrows in the figure represent red ink or red fluid uniformly mixed with red ink, and the solid arrows represent colorless fluid.

[0075] The observation results are as follows:

[0076] The microcatheters of Examples 1 to 4 can locally change the laminar flow state, have good anti-laminar flow effect, and the color uniformity of the liquid flowing out of the 3 outlets is high, indicating that the liquid medicine is evenly mixed and can achieve uniform drug delivery effect in each branch pipeline in all directions. The microcatheter is not easy to adhere to the wall, and even if it adheres locally or is offset, it still has the anti-laminar flow effect and can achieve uniform drug delivery.

[0077] After inputting the simulated liquid medicine in Control 1, the fluid flow state is laminar flow. The microcatheter is easy to adhere to the wall, and most of the liquid medicine can only enter one pipeline. The mixing uniformity of the liquid medicine is poor, resulting in the inability of the drug to be fully mixed after drug delivery, and then the phenomenon of flowing away along the branch blood vessels occurs, affecting the local drug delivery effect.

[0078] The microcatheter of Control 2 can locally change the laminar flow state, but the anti-laminar flow effect is unstable. The microcatheter is easy to adhere to the wall, and the anti-laminar flow effect becomes worse after adhesion. Most of the liquid medicine can only enter one pipeline, and the mixing uniformity of the liquid medicine is poor.

[0079] The microcatheter of Control 3 can locally change the laminar flow state, but the anti-laminar flow effect is unstable. The microcatheter is easy to adhere to the wall, and the anti-laminar flow effect becomes worse after adhesion. The color uniformity of the liquid flowing out of the 3 outlets is poor, and the mixing uniformity of the liquid medicine is poor.

[0080] The above results show that by setting the gradually changing side holes in a spiral distribution, the present application can achieve a stable and good anti-laminar flow effect, realizing 360° uniform liquid outlet. Even in the cases of catheter offset, wall attachment, bending, etc., the anti-laminar flow effect can still be achieved, so as to uniformly mix the liquid medicine in all directions of the blood, enabling all blood vessel branches to obtain appropriate drug supply and realizing a comprehensive and uniform local drug delivery effect. However, for the side hole design with liquid outlet in the same direction or side holes of the same size, the liquid outlet volume decreases from the proximal end to the distal end, and the uniform liquid outlet in all directions cannot be achieved, resulting in a poor anti-laminar flow effect. Especially after the micro-catheter adheres to the wall, the blood in some directions cannot mix enough drugs, and some blood vessel branches cannot obtain enough drugs, thus failing to achieve the comprehensive drug delivery effect.

[0081] The above description is only an exemplary embodiment of the present disclosure and is not intended to limit the protection scope of the present disclosure. The protection scope of the present disclosure is determined by the appended claims.

Claims

1. A laminar flow resistant microcatheter, characterized in that: It includes, from the proximal end to the distal end, a delivery section, a side opening section, and a terminal section. The length of the terminal section is greater than 4 mm; The microcatheter has an inner lumen, and the outer diameter of the delivery section and the terminal section is 1.5F to 4F, and the inner diameter is 0.40mm to 1.2mm; The side opening section is provided with more than 6 side openings, wherein the distance between adjacent side openings is 2.0 to 2.4 mm, and the angle relative to the axis is greater than or equal to 45° and less than or equal to 90°, or greater than or equal to 60° and less than or equal to 80°, and the area of ​​each side opening is independently 0.01 mm 2 To 0.1mm 2 , and the area of ​​the side opening increases from the proximal end to the distal end. 2 . The laminar flow-resistant microcatheter according to claim 1 , wherein the length of the terminal segment is greater than 6 mm, greater than 8 mm, greater than 10 mm, greater than 12 mm, or greater than 20 mm. The laminar flow resistant microcatheter according to claim 1 , wherein the side opening section is directly connected to the terminal section.

4. The laminar flow-resistant microcatheter according to claim 1, wherein a visualization mark is provided at at least one of the following positions: 1-4 mm from the most distal end of the microcatheter, 1-4 mm from the distal end of the side opening section, and 1-4 mm from the proximal end of the side opening section.

5. The laminar flow-resistant microcatheter according to claim 1, wherein the distance between adjacent side openings is 2.1 to 2.3 mm, and the angle relative to the axis is greater than or equal to 65° and less than or equal to 78°, and the area of ​​each side opening is independently 0.015 mm 2 Up to 0.08mm 2 .

6. The anti-laminar flow microcatheter according to claim 1, characterized in that: The side opening section is provided with 7 to 10 side openings, and the side openings are circular or elliptical in shape.

7. The laminar flow resistant microcatheter according to claim 1, wherein the outer surface of the microcatheter is provided with an anti-coagulation coating.

8. The laminar flow resistant microcatheter of claim 1, wherein the length of the delivery section is 0.4 to 1.5 m, 0.8 to 1.3 m, or 1.1 to 1.3 m.

9. The laminar flow-resistant microcatheter according to claim 1, wherein the microcatheter has an inner layer and an outer layer, wherein the inner layer is made of polytetrafluoroethylene (PTFE), and the outer layer is made of any one of the following materials: polyether block polyamide (pebax), nylon, and a braided layer is optionally provided between the inner layer and the outer layer.

10. The laminar flow resistant microcatheter of claim 9, wherein the braided layer is disposed on the delivery section such that the delivery section is shapeable.

11. The laminar flow resistant microcatheter according to claim 9, wherein the end section and the side opening section are not provided with a braided layer, thereby making the catheter relatively flexible. 12 . The laminar flow-resistant microcatheter according to claim 1 , wherein the inner cavity is through-hole or non-through-hole, the delivery section is not provided with side openings, and the terminal section is straight.

Images