CN115644990B - Aspiration catheter for interventional procedures - Google Patents

Abstract

The invention discloses a suction catheter for interventional operation, which comprises an outer sleeve and a reinforcing layer, wherein the outer sleeve extends along the axial direction, the outer sleeve is arranged on the outer layer of the reinforcing layer in the radial direction, the outer sleeve sequentially comprises a tail end, a far end section, a middle section and a near end section along the axial direction, and the material hardness of the far end section, the middle section and the near end section is sequentially improved; the material hardness of the middle section is sequentially increased along the axial direction from the distal section to the proximal section; the reinforcing layer in the distal section includes a spring structure, the reinforcing layer in the intermediate section includes a spring structure and a woven mesh tube structure, and the reinforcing layer in the proximal section includes a woven mesh tube structure. The suction catheter for interventional operation solves the problem that the inner diameter of the catheter cannot suck out emboli with larger volume; the problem of larger inner diameter catheters being difficult to traverse through tortuous vascular pathways; the catheter is easy to bend after passing through a smaller path; the catheter is easy to collapse under the condition of high suction negative pressure.

Description

Aspiration catheters for interventional procedures

Technical Field

The present invention relates to an intravascular treatment system for intravascular embolism or thrombosis of a human patient, and more particularly to an aspiration catheter for interventional surgery.

Background technique

The blood clot may be present in the deep veins, or it may flow into the pulmonary artery with the blood flow, causing blockage of blood flow in the pulmonary artery, thereby affecting the gas exchange of the blood.

Currently available technologies to restore blood flow through occluded vessels include:

1. Embolectomy, where a balloon is placed at the site of the occlusion and the embolus is removed by withdrawing the balloon;

2. Balloon angioplasty, in which a balloon-tipped catheter is introduced into the vessel (e.g., usually via an introducer catheter), then advanced to the site of the occlusion and inflated to dilate the stenosis. Balloon angioplasty is suitable for treating vascular stenosis but is generally ineffective for treating acute thromboembolism because none of the occlusion is removed and restenosis often occurs after dilation;

3. Another percutaneous technique involves placing a catheter near the clot and infusing streptokinase, urokinase, or other thrombolytic agents to dissolve the clot. Thrombolysis usually takes hours to days to be successful. In addition, thrombolytic agents may cause bleeding, and in many patients thrombolytic agents cannot be used at all;

4. The catheter is inserted through the blood vessel, and the distal end of the catheter is brought close to the embolus. Negative pressure is created through the syringe connected to the proximal end of the catheter to achieve the effect of aspirating the embolus.

The existing catheter has the following problems:

1. The inner diameter of catheter products is small and is not enough to suck out large emboli;

2. Larger inner diameter catheter products can effectively aspirate, but their larger size makes it difficult to pass through tortuous blood vessels;

3. The catheter is prone to bending after passing through a smaller path, so effective suction cannot be completed;

4. When the negative pressure of suction is large, the catheter (the softer part, such as the distal end) tends to collapse first, causing the inner diameter of this part of the catheter to become smaller, thus affecting the efficiency of suction.

Summary of the invention

In view of the problems existing in the prior art, such as the inner diameter being too small to suck out larger embolic objects, the larger sized catheter making it difficult to pass through a curved blood vessel path, the catheter being easily bent after passing through a smaller path, and the catheter being easily collapsed under a large suction negative pressure, the present invention provides an aspiration catheter for interventional surgery, which at least solves the problems that the inner diameter of the catheter cannot suck out larger embolic objects, the larger inner diameter catheter is difficult to pass through a curved blood vessel path, the catheter is easily bent after passing through a smaller path, and the catheter is easily collapsed under a large suction negative pressure.

To achieve the above object, the present invention adopts the following technical solution:

A suction catheter for interventional surgery comprises an outer sleeve and a reinforcement layer extending in the axial direction, wherein the outer sleeve is arranged on the outer layer of the reinforcement layer in the radial direction, and the outer sleeve comprises a terminal end, a distal section, a middle section, and a proximal section in the axial direction, wherein the material hardness of the distal section, the middle section, and the proximal section increases in sequence; the material hardness of the middle section increases in sequence from the distal section to the proximal section in the axial direction; the reinforcement layer in the distal section comprises a spring structure, the reinforcement layer in the middle section comprises a spring structure and a braided mesh tube structure, and the reinforcement layer in the proximal section comprises a braided mesh tube structure.

As an embodiment of the present invention, the axial length of the terminal end is 10 mm, the axial length of the distal end section is 400 mm, the axial length of the middle section is 120 mm, and the axial length of the proximal end section is 500 mm.

As an embodiment of the present invention, the material hardness of the end is greater than or equal to 35D, the material hardness of the distal segment is less than or equal to 35D, the material hardness of the middle segment is 42D-63D, and the material hardness of the proximal segment is greater than or equal to 63D.

As an embodiment of the present invention, the material hardness of the middle section increases from 42D to 63D along the axial direction from the distal section to the proximal section.

As an embodiment of the present invention, the braided mesh tube structure in the middle section includes a first metal flat wire, and the first metal flat wire has a thickness of 0.001-0.003 inches and a width of 0.003-0.005 inches.

As an embodiment of the present invention, the spring structure in the middle section includes a second metal flat wire, and the second metal flat wire has a thickness of 0.002-0.005 inches and a width of 0.007-0.015 inches.

As an embodiment of the present invention, the second flat metal wire of the spring structure in the distal section has a thickness greater than 0.004 inches and a width greater than 0.01 inches.

As an embodiment of the present invention, the outer diameter of the suction catheter ranges from 16Fr to 24Fr; when the outer diameter is 16Fr, the inner diameter of the suction catheter is not less than 4.2mm; when the outer diameter is 24Fr, the inner diameter of the suction catheter is not less than 7mm.

As an embodiment of the present invention, the inner diameter of the proximal section is greater than the inner diameter of the distal section.

As an embodiment of the present invention, when the outer diameter is 16 Fr, the inner diameter of the proximal section is greater than 5 mm; when the outer diameter is 24 Fr, the inner diameter of the proximal section is greater than 8 mm.

In the above technical solution, the catheter of the present invention has a larger inner diameter and can suck out larger emboli. In the case of a larger inner diameter, the catheter can also pass through a curved blood vessel path without causing bending and collapse problems.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the structure of a thrombus treatment device;

FIG2 is a schematic diagram of the external structure of the catheter of the present invention;

FIG3 is a schematic diagram of the internal structure of the catheter of the present invention;

Fig. 4 is a schematic diagram of an anti-collapse test;

Fig. 5a is a schematic cross-sectional view of a catheter without collapse;

FIG. 5 b is a schematic diagram of a collapsed catheter cross section.

In the figure:

100-suction catheter, 200-hemostasis valve, 300-pressure source, 400-switch valve, 500-quick disassembly mechanism, 11-outer sleeve, 12-reinforcement layer, 13-inner layer, 14-end, 15-distal section, 16-middle section, 17-proximal section, 21-spring structure, 22-woven mesh tube structure, 31-plastic sheet.

Detailed ways

The following is a further clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings and embodiments. Obviously, the described embodiments are used to explain the technical solutions of the present invention, and do not mean that all implementation methods of the present invention have been exhaustively listed.

Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

Regarding the terms "distal side/distal end" and "proximal side/proximal end" in this specification, the proximal side/proximal end refers to the end close to the operator, and the distal side/distal end refers to the end away from the operator or entering the human blood vessel. Each component may have a proximal end and a distal end, and the proximal end/distal end is a description of the relative direction/position, and does not directly represent the distance.

As shown in FIG1 , the suction catheter 100 of the present invention is applied to a thrombus treatment device. The thrombus treatment device mainly includes a suction catheter 100, a hemostatic valve 200, a pressure source 300, a switch valve 400 and a quick disassembly mechanism 500. The suction catheter 100 is a long tube, as shown in the circled part of FIG1 , having two ends, a proximal end and a distal end, and the entire interior between the proximal end and the distal end of the suction catheter 100 is hollow, forming a long hollow flexible tube. The distal end of the suction catheter 100 enters the human blood vessel, and the proximal end remains outside the human body and/or is connected to the hemostatic valve 200. The proximal end of the suction catheter 100 is connected to the hemostatic valve 200, the pressure source 300 is connected to the hemostatic valve 200 through the quick disassembly mechanism 500, and the switch valve 400 can be set between the quick disassembly mechanism 500 and the second bifurcation.

As shown in Figures 2 and 3, the suction catheter 100 is a long tube that is hollow in the middle. The suction catheter 100 includes an outer sleeve 11 extending in the axial direction, a reinforcement layer 12 and an inner layer 13. The outer sleeve 11 is arranged on the outer layer of the reinforcement layer 12 in the radial direction, and the inner layer 13 is arranged inside the reinforcement layer 12, thereby forming a three-layer tube structure. The outer sleeve 11, the reinforcement layer 12 and the inner layer 13 are the structural layers of the suction catheter 100 in the radial direction. As an embodiment of the present invention, the material of the inner layer 13 is polytetrafluoroethylene, and the material of the reinforcement layer 12 is selected as metal to constitute a metal reinforcement layer. The outer sleeve 11 of the present invention adopts a variable material structure to form a change in material in the axial direction, thereby forming a change in the hardness of the outer sleeve 11 in the axial direction.

Continuing to refer to FIG. 2 and FIG. 3, the outer sleeve 11 includes a terminal 14, a distal section 15, an intermediate section 16, and a proximal section 17 in the axial direction. The terminal 14, the distal section 15, the intermediate section 16, and the proximal section 17 are the structural divisions of the outer sleeve 11 of the suction catheter 100 in the axial direction. Among them, the terminal 14 is the end closest to the human organ, and the proximal section 17 is the end closest to the operator. As an embodiment of the present invention, the outer sleeve 11 is a 1030mm cylindrical catheter, the terminal 14 has an axial length of 10mm, the distal section 15 has an axial length of 400mm, the intermediate section 16 has an axial length of 120mm, and the proximal section 17 has an axial length of 500mm. It can be understood by those skilled in the art that the above-mentioned length selection is only one of many embodiments of the present invention, and is not a limitation of the present invention. In other embodiments of the present invention, the terminal 14, the distal section 15, the intermediate section 16, and the proximal section 17 can have other length selections in the axial direction, which can all achieve the technical purpose of the present invention and achieve the technical effect of the present invention.

2 and 3, the suction catheter 100 of the present invention is a large-caliber catheter, so the selection of its outer diameter (circumference) and inner diameter has specific constraints. In the present invention, the outer diameter of the suction catheter 100 ranges from 16Fr to 24Fr, where Fr is the abbreviation of the unit of length French.

When the outer diameter of the suction catheter 100 is 16Fr, its overall inner diameter is not less than 4.2mm, and when the outer diameter of the suction catheter 100 is 24Fr, its overall inner diameter is not less than 7mm. In addition, since the suction catheter 100 is divided into the terminal end 14, the distal section 15, the middle section 16 and the proximal section 17 in the axial direction, its inner diameter may also vary in each section. For example, the inner diameter of the proximal section 17 may be larger than the inner diameter of the distal section 15. When the outer diameter is 16Fr, the inner diameter of the proximal section 17 is greater than 5mm, and when the outer diameter is 24Fr, the inner diameter of the proximal section 17 is greater than 8mm. At this time, the outer diameter of the distal section 15 is correspondingly smaller than the outer diameter of the proximal section 17.

According to the Hagen–Poiseuille Law, the radius of the inner diameter (inner layer 13) of the suction catheter 100 and the flow rate are in direct proportion to the fourth power. The present invention selects to make the suction catheter 100 with a large diameter, so that the suction efficiency (suction flow rate) of the suction catheter 100 can be significantly improved. The specific formula is as follows:

,

Where Q = suction efficiency of the catheter, π = pi, r = inner radius, ΔP = pressure difference, ŋ = liquid viscosity, and L = catheter length.

The outer diameter range of 16Fr-24Fr and the inner diameter range mentioned above make the inner diameter and outer diameter of the suction catheter 100 of the present invention larger than those of ordinary interventional treatment catheters. However, as the inner diameter and outer diameter of the suction catheter 100 increase, its anti-bending performance and anti-collapse performance will be challenged. Ordinary interventional suction catheters cannot achieve the inner diameter and outer diameter of this size, because large-sized catheters will have serious bending and collapse problems during use.

As shown in FIG. 2 and FIG. 3 , in order to match the above-mentioned large-caliber suction catheter 100, so that the suction catheter 100 can meet the anti-bending performance and anti-collapse performance while maintaining the large caliber, the material hardness of the distal segment 15, the middle segment 16 and the proximal segment 17 is increased in sequence in material selection, and the material hardness of the middle segment 16 is increased in sequence along the axial direction from the distal segment 15 to the proximal segment 17, but the material hardness of the terminal 14 is independent, and the material hardness of the terminal 14 generally needs to be greater than (at least equal to) the material hardness of the distal segment 15. As an embodiment of the present invention, the material of the distal segment 15 is a combination of NEUSoft862 (thermoplastic polyurethane) and/or Pebax25D (polyether block amide).

In order to meet the above-mentioned material selection conditions and satisfy the bending resistance and collapse resistance of the suction catheter 100, the material hardness of the terminal 14 is greater than or equal to 35D (where D is the Shore hardness unit), the material hardness of the distal segment 15 is less than or equal to 35D, and the material hardness of the middle segment 16 is 42D-63D. The material hardness of the middle segment 16 increases from 42D to 55D along the axial direction from the distal segment 15 to the proximal segment 17, and finally increases to 63D. The material hardness of the proximal segment 17 is greater than or equal to 63D.

As a first specific option of the above embodiment, the material hardness of the end 14 is 35D, the material hardness of the distal segment 15 is 35D, the material hardness of the middle segment 16 changes continuously from 42D to 55D along the axial direction from the distal segment 15 to the proximal segment 17, and then continuously changes to 63D, and the material hardness of the proximal segment 17 is 63D.

As a second specific option of the above embodiment, the material hardness of the end 14 is 35D, the material hardness of the distal segment 15 is 25D, the material hardness of the middle segment 16 changes continuously from 42D to 55D along the axial direction from the distal segment 15 to the proximal segment 17, and then continuously changes to 63D, and the material hardness of the proximal segment 17 is 70D.

The change in the hardness of the outer sleeve 11 material helps to achieve the anti-bending and anti-collapse performance of the suction catheter 100. In addition to the change in the hardness of the outer sleeve 11 material, the material and structure selection of the inner reinforcement layer 12 of the outer sleeve 11 also affect the anti-bending and anti-collapse performance of the suction catheter 100.

Continuing to refer to FIG. 2 and FIG. 3, in order to match the material selection of the end 14, the distal segment 15, the middle segment 16, and the proximal segment 17 of the outer sleeve 11, the reinforcement layer 12 also changes in structure, and the change corresponds to the segmentation of the outer sleeve 11. As shown in FIG. 2 and FIG. 3, the reinforcement layer 12 includes a spring structure 21 and a braided mesh structure 22, and the two have corresponding distribution areas in the axial direction. The portion of the reinforcement layer 12 corresponding to the distal segment 15 includes the spring structure 21, the portion of the reinforcement layer 12 corresponding to the middle segment 16 includes the spring structure 21 and the braided mesh structure 22, and the portion of the reinforcement layer 12 corresponding to the proximal segment 17 includes the braided mesh structure 22.

As an embodiment of the present invention, the thickness of the second metal flat wire of the spring structure 21 corresponding to the distal section 15 is greater than 0.004 inches and the width is greater than 0.01 inches. The braided mesh tube structure 22 corresponding to the middle section 16 includes a first metal flat wire, the thickness of the first metal flat wire is 0.001-0.003 inches, and the width is 0.003-0.005 inches; the spring structure 21 in the middle section 16 includes a second metal flat wire, the width of the second metal flat wire is 0.007-0.015 inches, and the thickness is 0.002-0.005 inches.

In order to verify that the suction catheter 100 can be pushed to the pulmonary artery trunk through the femoral artery with the dilator, and does not bend when passing through the left and right pulmonary arteries, the present invention conducted the following experiment: the suction catheter 100 was wrapped 180 degrees on a cylinder with different outer diameters, and after wrapping, the suction catheter 100 was observed to see if it was bent. The present invention conducted experiments on different combinations of the reinforcement layer 12 and the outer sleeve 11 in the three-layer structure of the suction catheter 100, and the anti-bending test results are as follows:

When the metal reinforcement layer adopts a spring structure, that is, the thickness of the second metal flat wire is 0.002 inches, the width is 0.008 inches, and the hardness of the outer sleeve 11 corresponding to this part is 35D, the minimum bending diameter is 60 mm.

When the metal reinforcement layer adopts a spring structure, that is, the thickness of the second metal flat wire is 0.003 inches, the width is 0.009 inches, and the hardness of the outer sleeve 11 corresponding to this part is 35D, the minimum bending diameter is 46 mm.

When the metal reinforcement layer adopts a spring structure, that is, the thickness of the second metal flat wire is 0.003 inches, the width is 0.009 inches, and the hardness of the outer sleeve 11 corresponding to this part is 63D, the minimum bending diameter is 72 mm.

When the metal reinforcement layer adopts a spring structure, that is, the thickness of the second metal flat wire is 0.004 inches, the width is 0.016 inches, and the hardness of the outer sleeve 11 corresponding to this part is 35D, the minimum bending diameter is 15 mm.

When the metal reinforcement layer adopts a spring structure, that is, the thickness of the second metal flat wire is 0.004 inches, the width is 0.016 inches, and the hardness of the outer sleeve 11 corresponding to this part is 55D, the minimum bending diameter is 42 mm.

When the metal reinforcement layer adopts a spring structure, that is, the thickness of the second metal flat wire is 0.004 inches, the width is 0.016 inches, and the hardness of the outer sleeve 11 corresponding to this part is 63D, the minimum bending diameter is 46 mm.

When the metal reinforcement layer adopts a spring structure, that is, the thickness of the second metal flat wire is 0.005 inches, the width is 0.015 inches, and the hardness of the outer sleeve 11 corresponding to this part is 25D, the minimum bending diameter is 15 mm.

When the metal reinforcement layer adopts a spring structure, that is, the thickness of the second metal flat wire is 0.005 inches, the width is 0.015 inches, and the hardness of the outer sleeve 11 corresponding to this part is 35D, the minimum bending diameter is 6 mm.

When the metal reinforcement layer adopts a braided mesh tube structure, that is, the thickness of the first metal flat wire is 0.002 inches, the width is 0.008 inches, and the hardness of the outer sleeve 11 corresponding to this part is 35D, the minimum bending diameter is 15 mm.

When the metal reinforcement layer adopts a braided mesh tube structure, that is, the thickness of the first metal flat wire is 0.002 inches, the width is 0.008 inches, and the hardness of the outer sleeve 11 corresponding to this part is 63D, the minimum bending diameter is 64mm.

When the metal reinforcement layer adopts a braided mesh tube structure, that is, the thickness of the first metal flat wire is 0.003 inches, the width is 0.007 inches, and the hardness of the outer sleeve 11 corresponding to this part is 42A+25D (where A and D are both Shore hardness units), the minimum bending diameter is 15mm.

When the metal reinforcement layer is made of round wire with a thickness of 0.002 inches and the hardness of the outer sleeve 11 corresponding to this portion is 35D, the minimum bending diameter is 60 mm.

The specific experimental data are shown in the following table:

,

It can be seen from the above table that when the thickness of the metal flat wire is 0.002-0.005 inches and the width is within 0.007-0.015 inches, it is combined with a material with a hardness of 42A-35D to resist bending of 15mm diameter, which is beneficial to the bending resistance.

In addition to the anti-bending performance, the material selection of the present invention is also reflected in the anti-collapse performance of the end 14 of the suction catheter 100. Referring to Figure 4, as an embodiment of the present invention, the length of the end 14 of the suction catheter 100 is about 10 mm, and the material hardness is greater than or equal to 35D, so that the end 14 will not collapse under the negative pressure suction of 97kpa.

As shown in FIG4 , in order to verify the effectiveness of catheter aspiration, the present invention conducted the following experiments:

A negative pressure of atmospheric pressure is applied to the proximal section 17 of the suction catheter 100, and the end 14 is blocked with a transparent plastic sheet 31 to observe whether the suction catheter 100 as a whole collapses. The present invention tests the end 14 of the 24Fr suction catheter 100 of different hardnesses, and the test results are as follows:

When the hardness of the tip 14 is 42A, the suction catheter 100 collapses and collapses severely, as shown in FIG. 5 b .

When the hardness of the tip 14 is 62A, the suction catheter 100 collapses and collapses severely, as shown in FIG. 5 b .

When the hardness of the tip 14 is 35D, the aspiration catheter 100 collapses, but only slightly, as shown in FIG. 5b.

When the hardness of the tip 14 is 45D, the aspiration catheter 100 does not collapse, as shown in FIG. 5 a .

When the hardness of the tip 14 is 63D, the aspiration catheter 100 does not collapse, as shown in FIG. 5 a .

The specific experimental data are shown in the following table:

,

It can be seen from the above table that when the material hardness of the end 14 is greater than or equal to 35D, the effectiveness of catheter suction can be guaranteed.

It can be seen from the above series of tests that in order to manufacture a large-caliber (16Fr-24Fr) catheter, the present invention simultaneously improves the structure/material of the outer sleeve 11 and the reinforcement layer 12 of the suction catheter 100. On the one hand, the hardness of the outer sleeve 11 changes in the axial direction, so that the hardness of the outer sleeve 11 gradually increases from the distal section 15 to the proximal section 17, and the farthest end (i.e., the end 14) of the suction catheter 100 is made of a material with a higher hardness, so as to maintain the anti-bending performance and anti-collapse performance under large caliber.

On the other hand, the material and hardness of the reinforcement layer 12 in the axial direction also change with the outer sleeve 11, using metal flat wire instead of traditional round wire, and the weaving method of the metal flat wire gradually changes from a spring structure to a woven mesh structure, and the thickness and width of the metal flat wire can also be changed accordingly.

It can be seen from the above embodiments that the present invention has tested various choices of materials for the outer sleeve 11 and the reinforcement layer 12, and finally determined the material/structure value range of the outer sleeve 11 and the reinforcement layer 12 suitable for the large-caliber suction catheter 100. Through the coordination and improvement of the outer sleeve 11 and the reinforcement layer 12, the suction catheter for interventional surgery of the present invention has at least the following beneficial effects:

1. The inner diameter of the catheter is large enough to aspirate larger emboli;

2. Catheters with larger inner diameters can pass through tortuous blood vessels;

3. The catheter will not bend after passing through a smaller path, so it will not affect effective suction;

4. The catheter will not collapse when the negative pressure of suction is large, so it will not affect the efficiency of suction.

As shown in this specification and claims, the words "a", "an", "an" and/or "the" do not specifically refer to the singular, but may include the plural, unless the context clearly implies an exception. In general, the terms "comprises" and "including" only mean that the steps and elements specifically identified are included, which do not constitute an exclusive list, and the method or apparatus may include other steps or elements.

Those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims (6)

1. A suction catheter for interventional surgery, comprising an outer sleeve extending axially and a reinforcement layer, wherein the outer sleeve is arranged radially outside the reinforcement layer, characterized in that: The outer sleeve comprises a terminal end, a distal end section, a middle section, and a proximal end section in sequence along the axial direction, wherein the material hardness of the distal end section, the middle section, and the proximal end section increases in sequence; The material hardness of the terminal end is greater than or equal to 35D, and the material hardness of the proximal end section is greater than or equal to 63D; The material hardness of the middle section increases in sequence from the distal section to the proximal section along the axial direction; The reinforcement layer includes a spring structure and a braided mesh tube structure, and the two have corresponding distribution areas in the axial direction, wherein the reinforcement layer in the distal segment is a spring structure, the reinforcement layer in the middle segment is a spring structure and a braided mesh tube structure, and the reinforcement layer in the proximal segment is a braided mesh tube structure; The material hardness of the middle section is 42D-63D; the braided mesh tube structure in the middle section includes a first metal flat wire, the thickness of the first metal flat wire is 0.001-0.003 inches, and the width is 0.003-0.005 inches; the spring structure in the middle section includes a second metal flat wire, the thickness of the second metal flat wire is 0.002-0.005 inches, and the width is 0.007-0.015 inches; The material hardness of the distal segment is less than or equal to 35D; the thickness of the second metal flat wire of the spring structure in the distal segment is greater than 0.004 inches and the width is greater than 0.01 inches; The outer diameter of the suction catheter ranges from 16Fr to 24Fr. 2. The aspiration catheter for interventional surgery according to claim 1, characterized in that: The axial length of the terminal end is 10 mm, the axial length of the distal end section is 400 mm, the axial length of the middle section is 120 mm, and the axial length of the proximal end section is 500 mm. 3. The aspiration catheter for interventional surgery according to claim 1, characterized in that: The material hardness of the middle section increases from 42D to 63D along the axial direction from the distal section to the proximal section. 4. The aspiration catheter for interventional surgery according to any one of claims 1 to 3, characterized in that: When the outer diameter is 16Fr, the inner diameter of the suction catheter is not less than 4.2mm; When the outer diameter is 24 Fr, the inner diameter of the suction catheter is not less than 7 mm. 5. The aspiration catheter for interventional surgery according to claim 4, characterized in that: The inner diameter of the proximal section is greater than the inner diameter of the distal section. 6. The aspiration catheter for interventional surgery according to claim 5, characterized in that: When the outer diameter is 16Fr, the inner diameter of the proximal section is greater than 5mm; When the outer diameter is 24 Fr, the inner diameter of the proximal section is greater than 8 mm.