Thrombolysis catheter

Abstract

The utility model relates to a thrombolysis catheter which comprises an outer catheter provided with a main body tube, the far end side of the main body tube is provided with a perfusion section, and the perfusion section is provided with a plurality of perfusion holes arranged at intervals in the axial direction; the inner pushing pipe is provided with a pipe body, and the pipe body is arranged in the main body pipe in a sliding and penetrating mode so as to selectively cover at least part of the perfusion holes and further adjust the effective length of the perfusion section; the core rod is arranged in the inner push tube and the outer guide tube in a sliding and penetrating manner; the plugging device comprises a capturing part located on the far-end side and a plugging part located on the near-end side, the capturing part and the plugging part are connected with each other, and the far end of the core rod is fixedly connected with the near end of the plugging part. The thrombolysis catheter can capture thrombus falling from the blood vessel wall, and is simple to operate and high in thrombus removal efficiency.

Description

Technical Field

[0001] This utility model relates to the field of medical devices, and in particular to a thrombolytic catheter. Background Technology

[0002] Acute deep vein thrombosis (DVT) of the lower extremities is a common peripheral vascular disease in clinical practice. In the acute phase, thrombus detachment can cause severe pulmonary embolism, and in the later stages, it can lead to a series of post-thrombotic syndromes (PTS), including chronic limb swelling, varicose veins, and deep vein valve insufficiency. Catheter-directed thrombolysis (CDT) is a surgical procedure for lower extremity swelling or ischemic pain caused by venous or arterial thrombosis from various causes. It involves placing a catheter directly under or near the thrombus and injecting thrombolytic drugs, such as urokinase, through the catheter to dissolve the thrombus and open the blood vessel. CDT has significant advantages, including a significantly higher thrombus dissolution rate, a lower incidence of PTS, shorter treatment time, and fewer complications, making it the preferred thrombolysis method in clinical practice.

[0003] Current thrombolytic catheters infuse thrombolytic solution into the blood vessel to remove the thrombus. However, once the thrombus breaks off from the blood vessel wall, it may travel through the bloodstream to other parts of the body, causing related diseases. Utility Model Content

[0004] Based on this, it is necessary to provide a thrombolytic catheter with the function of capturing thrombi detached from the blood vessel wall to address the above-mentioned problems. This thrombolytic catheter includes: an external catheter having a main tube with a perfusion zone at its distal end, the perfusion zone having a plurality of perfusion holes spaced apart along the axial direction; an internal push tube having a tube body that slides through the main tube to selectively cover at least part of the perfusion holes, thereby adjusting the effective length of the perfusion zone; a core rod that slides through the internal push tube and the external catheter; and an occluder including a capture portion located at the distal end and an occlusion portion located at the proximal end, connected to each other, the distal end of the core rod being fixedly connected to the proximal end of the occlusion portion; when the occlusion portion retracts to the distal end of the lumen of the external catheter to block the distal opening of the external catheter, the capture portion can be located outside the external catheter and in a natural state.

[0005] Furthermore, the blocking part is provided with a first flow-blocking membrane, and / or the capturing part is provided with a second flow-blocking membrane.

[0006] Furthermore, in its natural state, the thickness of the blocking portion is greater than the thickness of the capturing portion, and / or the diameter of the blocking portion is smaller than the diameter of the capturing portion.

[0007] Furthermore, in its natural state, the outer periphery of the sealing portion has a groove, or the shape of the capturing portion is substantially the same as that of the sealing portion.

[0008] Furthermore, the sealing part includes a sealing disc woven from braided yarn, and a connecting nut that connects to the core rod is provided on the proximal side of the sealing disc.

[0009] Furthermore, the capturing part includes a capturing disc woven from braided filaments; or, the capturing part includes a filter composed of mesh wires, the filter including a distal end, a distal filter screen, a support section, a proximal filter screen, and a proximal end connected in sequence from the distal end to the proximal end, the distal filter screen and the proximal filter screen are both spatial conical structures composed of multiple mesh wires, and the proximal end is fixedly connected to the distal side of the sealing disc.

[0010] Furthermore, the density of the mesh structure of the distal filter is greater than the density of the mesh structure of the proximal filter.

[0011] Furthermore, a first developing ring is provided on the distal end of the main tube, and a second developing ring is provided on the distal end of the tube body.

[0012] Furthermore, a three-way hemostatic valve is provided at the proximal end of the inner push tube and communicates with it. The proximal end of the core rod can pass through the three-way hemostatic valve and extend into the inner push tube. The three-way hemostatic valve can be clearance-fitted or interference-fitted with the core rod.

[0013] Furthermore, a sealing ring is provided on the outer periphery of the distal end of the tube, and the sealing ring slides and seals with the inner wall of the outer conduit.

[0014] Furthermore, the outer diameter of the tube is 85%-95% of the inner diameter of the main tube.

[0015] Furthermore, an indicator mark is provided on the proximal outer periphery of the inner push tube, the indicator mark being used to mark the relative position of the inner push tube relative to the outer catheter.

[0016] The technical solution of this utility model has the following beneficial effects: The occluder used in this utility model has a occlusion part and a capture part, which can capture the thrombus while occluding the end of the external catheter, preventing the thrombus from falling off the blood vessel wall and flowing with the blood to other parts of the human body. After the operation, the occluder can be withdrawn proximally into the external catheter and removed from the human body. The operation is simple and convenient, and has a high thrombus removal efficiency. Attached Figure Description

[0017] Figure 1 This is an overall structural diagram of the thrombolytic catheter in the first embodiment;

[0018] Figure 2 This is a partial cross-sectional view of the external catheter in the first embodiment;

[0019] Figure 3 for Figure 1 Enlarged view of point A in the image;

[0020] Figure 4 This is a partial cross-sectional view of the thrombolytic catheter in the first embodiment;

[0021] Figure 5 for Figure 4 Enlarged view of point B in the image;

[0022] Figure 6 This is an overall structural diagram of the plugging device in the first embodiment;

[0023] Figure 7 This is a schematic diagram of the thrombolysis process using the thrombolysis catheter in the first embodiment;

[0024] Figure 8 This is a structural diagram of another embodiment of the plugging device;

[0025] Figure 9 This is a schematic diagram of the structure for adjusting the effective length of the irrigation zone of the thrombolytic catheter in the first embodiment;

[0026] Figure 10 This is a structural diagram of the plugging device in the second embodiment; Detailed Implementation

[0027] To make the above-mentioned objectives, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0028] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intermediate element present. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intermediate element present. The terms "upper," "lower," "left," "right," and similar expressions used to indicate orientation are for illustrative purposes only and do not represent the only possible implementation.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0030] It should be noted that, for medical devices, the end of the medical device that is relatively closer to the operator is generally called the "proximal end," and the end that is relatively farther from the operator is called the "distal end." Based on this principle, the "proximal end" and "distal end" of any component of the delivery system are defined. "Proximal end" and "distal end" are only used to describe the orientation and do not refer to the end face of the proximal end or the end face of the distal end. "Axial axis" or "longitudinal axis" refers to the direction parallel to the line connecting the center of the distal end and the center of the proximal end of the medical device. "Radial axis" or "lateral axis" refers to the direction perpendicular to the axial direction.

[0031] First Embodiment

[0032] See Figure 1 As shown, this embodiment relates to a thrombolytic catheter 1, which has a central axis and includes an outer catheter 10 and an inner push tube 20 slidably inserted into the outer catheter 10. A three-way hemostatic valve 30 is connected to the proximal end of the inner push tube 20. The distal end of a core rod 40 can sequentially pass through the three-way hemostatic valve 30 and the inner push tube 20 to enter the outer catheter 10 and can exit from the outer guide rod 10. The proximal end of the core rod 40 is exposed outside the three-way hemostatic valve 30 for easy operation by the operator. An occluder 50 is connected to the distal end of the core rod 40. In this embodiment, the core rod 40 is connected to the proximal end of the occluder via a threaded connection. The core rod 40 needs to meet certain mechanical properties to enable pushing, pulling, and other operations on the occluder 50. It can be made of nickel-titanium steel cable or other polymer materials or alloy materials that meet mechanical properties.

[0033] See Figure 1-2As shown, the external catheter 10 is a hollow tubular structure, including a main tube 11 and a tube seat 12 connected to the proximal end of the main tube 11. The tube seat 12 is used to connect to the push tube 20, which is inserted into the main tube 11 through the tube seat 12. The distal end of the main tube 11 has a catheter tip 111, which is a tapered tube with a decreasing outer diameter from the proximal end to the distal end to facilitate entry into the human body or movement in blood vessels. The distal end of the main tube 11 has an infusion zone with multiple infusion holes 113 spaced apart along the axial direction; that is, the area of ​​the main tube 11 with multiple infusion holes 113 constitutes the infusion zone. The infusion holes 113 are evenly distributed axially or the spacing between adjacent infusion holes 113 gradually increases from the proximal end to the distal end. Furthermore, the irrigation holes 113 can be arranged in a straight line (i.e., the trajectory of the line connecting all the irrigation holes is a straight line) or a spiral (i.e., the trajectory of the line connecting all the irrigation holes is a spiral) in the axial direction. There can be only one irrigation hole 113 or multiple irrigation holes spaced apart in the circumferential direction. The irrigation hole 112 is a through hole provided on the wall of the main tube 11, and its cross-sectional shape can be circular, elliptical, square, strip-shaped, polygonal, or other shapes. There is no specific limitation on the shape of the irrigation hole 112, as long as the thrombolytic fluid can be sprayed out of the main tube 11 through the irrigation hole 112. In addition, a first imaging ring 112 is also provided on the main tube 11. The first imaging ring 112 can be sleeved on the outer circumference of the main tube 11 or embedded in the wall of the main tube 11. The first imaging ring 112 is used to display the specific position of the main tube 11 in the human body during surgery.

[0034] See Figure 3 As shown, exemplarily, the tubular hole 112 in this embodiment is a long and narrow strip-shaped hole.

[0035] See Figure 1 , 4As shown in Figure -5, the thrombolytic catheter 1 will continue to be described. The push tube 20 includes a tube body 21 and a connector 22 connected to the proximal side of the tube body 21. The tube body 21 is movably inserted into the outer catheter 10, and the length of the tube body 21 inserted into the outer catheter 10 can be changed by pushing the connector 22. To facilitate sliding, the outer diameter of the tube body 21 is smaller than the inner diameter of the main tube 11, i.e., they are clearance-fitted. To prevent liquid from flowing out along the annular gap between them, a sealing ring 212 is also provided on the outer periphery of the distal side of the tube body 21. This sealing ring 212 is elastic and has an interference fit with the tube body 11. When the tube body 21 slides in the main tube 11, the distal opening of the annular gap between them is sealed by the sealing ring 212, thereby preventing the thrombolytic fluid from flowing out from the proximal side of the outer catheter 10 through the annular gap. In addition, a second imaging ring 212 is provided at the far end of the outer periphery of the tube body 21. The second imaging ring 212 can be used to display the position of the tube body 21 in the human body, and can cooperate with the second imaging ring 112 to indicate the relative position between the tube body 21 and the main tube 11.

[0036] When the tube body 21 slides within the main tube 11 and partially covers the infusion hole 112, the covered infusion hole 112 is closed due to the obstruction of the tube body 21, preventing the thrombolytic fluid from flowing out of that portion of the infusion hole 112. This allows the effective length of the infusion zone of the thrombolytic catheter to be changed by sliding the inner push tube 10. Furthermore, to facilitate viewing the length of the tube body 21 inserted into the main tube 11 and to allow the operator to better adjust the effective length of the infusion zone, an indicator mark 213 is provided on the outer periphery of the inner push tube 20. This indicator mark can be a scale line, a marker symbol with specific intervals, or other symbols that can measure and mark the distance the inner push tube 20 moves relative to the outer catheter 10.

[0037] In other embodiments, a sealing ring may be omitted, allowing the outer diameter of the tube body 21 to be close to the inner diameter of the main tube 11 while being smaller than the inner diameter of the main tube 11, thus forming a small annular gap between them. Because this annular gap is small, only a small amount of thrombolytic fluid flows out from it, having no substantial impact on the overall tubular shape of the thrombolytic catheter. Specifically, the outer diameter of the inner tube body 21 can be set to 85%-95% of the inner diameter of the main tube 11.

[0038] The tube body 21 is connected to a three-way hemostatic valve 30 via a pipe connector 22. The three-way hemostatic valve 30 includes a valve body 32 and a side branch 31, both of which are connected to the inner push tube 20. The side branch 31 is used to connect to a syringe or delivery pump to deliver expelled fluid (such as saline) or thrombolytic fluid into the inner push tube 10. A knob 33 is fitted around the proximal periphery of the valve body 32. A sealing plate (not shown in the figure) is provided inside the valve body 32, and a through hole is provided on the sealing plate for the core rod 40 to pass through. This through hole can be a circular hole or a long strip cut, etc. When the core rod 40 passes through the through hole and reaches the predetermined position, tightening the knob 33 reduces the size of the through hole to wrap around the core rod 40, thereby sealing the core rod 40 and preventing liquid from flowing out of the valve body 32 through the core rod 40. When it is necessary to move the core rod 40, the knob 33 is loosened to reduce the friction between them.

[0039] See Figure 6 The structure of the plugger 50 is described below. The plugger 50 includes a capturing part 52 and a plugging part 51 connected to each other by a waist part 57, with the capturing part 52 located at the distal end of the plugging part. A connecting nut 53 is provided on the side of the plugging part 51 away from the capturing part 52, i.e., at the proximal end of the plugging part 51. This connecting nut has internal threads for threaded connection with the end of the core rod 40. In this embodiment, both the plugging part 51 and the capturing part 52 are disc-shaped structures with a woven mesh, constructed from nickel-titanium wire. The plugging part 51 includes a plugging disc woven from the woven wires, and the capturing part 52 includes a capturing disc woven from the woven wires. A cap 56 is provided at the distal end of the capturing disc to gather and fix the ends of the woven wires. The plugging disc has a first flow-blocking membrane 54, and the capturing disc has a second flow-blocking membrane 52. Of course, in other embodiments, the flow-blocking membrane may not be provided in the capturing disc or the plugging disc.

[0040] In its natural state, the thickness of the occlusion portion 51 is greater than the thickness of the capture portion 52. Increasing the thickness of the occlusion portion 51 to be greater than that of the capture portion 52 increases its contact length with the inner wall of the external catheter 10 after compression, improving the stability of its connection with the external catheter 10 and preventing the occlusion disc 51 from detaching from the external catheter 10 due to liquid pressure or impact. Furthermore, to enhance the friction between the occlusion portion 51 and the inner wall of the external catheter 10 and further strengthen their connection, a groove 57 is provided on the outer periphery of the occlusion portion 51. In its natural state, the outer diameter of the capture portion 52 can be set to be greater than the outer diameter of the occlusion portion 51. The size and model of the capture portion 52 can be matched and selected according to the size of the blood vessel, making it close to (smaller than) or 30%-50% larger than the inner diameter of the blood vessel. The closer the capture portion 52 is to the inner diameter of the blood vessel, the less likely the free thrombus 70A is to escape from the gap between the capture portion 52 and the blood vessel. When the capture section 52 is fitted with a blood vessel through an interference fit, a flow-blocking membrane may not be provided in the capture section 52 to ensure smooth blood flow. The outer diameter of the capture section 52 is larger than the outer diameter of the blocking section 51, which allows for a reduction in the outer diameter of the blocking section 51 while meeting the size requirements of the capture section 52, thereby reducing the overall size of the occluder 50.

[0041] See Figure 7As shown, when thrombolysis of the thrombus 70 within the blood vessel 60 is required, the external catheter 10 is delivered to a predetermined position within the blood vessel 70, allowing the thrombolytic solution through the infusion port 113 to be sprayed onto the thrombus 70. Before injecting the thrombolytic solution, the position of the mandrel 40 is adjusted so that the occlusion part 51 is located at the distal end of the lumen of the external catheter 10, and the capture part 52 is located outside the lumen of the external catheter 10. For example, the mandrel 40 can be extended from the distal end of the external catheter 10, and then the mandrel 40 can be connected to the occlusion disc 51 and pulled proximally, causing the occlusion disc 51 to retract into the external catheter 10 while the capture part 52 is located outside the external catheter. Since the outer diameter of the occlusion part 51 is larger than the inner diameter of the external catheter 10 in its natural state, the occlusion part 51, after retracting into the distal lumen of the external catheter 10, can effectively seal the distal opening of the external catheter 10. The first flow-blocking membrane 54 further enhances the sealing effect of the sealing part 51, preventing liquid from flowing out through the sealing part 51. The capturing part 52 is located outside the outer conduit 10 and is in its natural state. In this invention, the natural state refers to the elastic component being in its naturally unfolded state when not compressed. When the thrombus 70 detaches and becomes a free thrombus 70A due to the dissolution and impact of the thrombolytic solution, as shown by the arrow in the figure, the free thrombus 70A will flow with the blood to the capturing part 52 and be captured. Specifically, when the free thrombus 70A flows to the capturing part 52, it will adhere to the outside or inside of the capturing part 52. When a second flow-blocking membrane 52 is provided inside the capturing part 52, small free thrombi 52 will pass through the woven mesh of the capturing part 52 and enter the interior, where they will be blocked by the second flow-blocking membrane 52, thus allowing even small free thrombi to be captured.

[0042] In other embodiments, such as Figure 8 The occluder 150 includes a capturing part 152 and an occluding part 151 connected to each other via a waist portion 157. The two parts are substantially identical in shape. "Substantially identical in shape" in this invention means that the two components have the same shape and size, including differences due to manufacturing tolerances, manufacturing errors, etc. A cap 156 is provided at the distal end of the capturing part 152, and a connecting nut 153 is provided at the proximal end of the occluding part 151. A first flow-blocking membrane 155 is provided in the capturing part 152, and a second flow-blocking membrane 154 is provided in the occluding part 151. When thrombolysis is required, the occluding part 151 is positioned on the distal end of the lumen of the external catheter 10 to achieve occlusion, and the capturing part 152 is positioned on the outer side of the lumen of the external catheter 10 to capture the free thrombus 70A. Setting the capturing part 152 and the occluding part 151 to have the same shape simplifies the mold-making process and facilitates the manufacture of the occluder 150.

[0043] See Figure 9As shown, for the external catheter 10, the length of its main body is L1, and the area with multiple perfusion holes 113 on its distal side constitutes the perfusion zone. The length L2 of the perfusion zone is the maximum length of thrombolytic solution that the external catheter 10 can perfuse, which is the axial length between the distal and proximal perfusion holes. When the push tube 20 moves distally along the lumen of the external catheter 10 and covers part of the perfusion holes, the effective length of the perfusion zone decreases from L2 to L3. Therefore, by adjusting the relative position of the push tube 20 to the external catheter 10, the effective length of the perfusion zone can be adjusted according to the actual thrombus size, thereby perfusing the thrombus-containing area of ​​the vessel wall with thrombus, improving thrombolytic efficiency and reducing the amount of thrombolytic solution used.

[0044] Second Embodiment

[0045] The thrombolytic catheter in this embodiment has a similar structure to the thrombolytic catheter in Embodiment 1. The difference is that the occluder in this embodiment is different from that in the first embodiment.

[0046] See Figure 10 As shown, the occluder 50a includes an occlusion part 80 and a capture part 100 connected to each other. The occlusion part 80 is the same as the occlusion part in Embodiment 1, which is also made of nickel-titanium wire woven into a disc shape, and has a cap 82 at its distal end. Unlike the first embodiment, the capture part 100 in this embodiment is not made of nickel-titanium wire woven into a disc, but is a filter made of mesh. Specifically, the filter has a distal end 91 and a proximal end 92 arranged opposite to each other, including a distal filter screen 931 near the distal end 91, a proximal filter screen 933 near the proximal end 92, and a support section 932 connecting the distal filter screen 931 and the proximal filter screen 933. The support section 932 is provided with a plurality of axially extending support rods 932a spaced apart in the circumferential direction. When the filter is outside the external catheter 10 and in its natural state, the distal filter screen 931 and the proximal filter screen 933 are used to capture thrombi. The distal filter 931 is formed by multiple mesh lines converging at the distal end 91 to form a spatial cone structure, while the proximal filter 933 is formed by multiple mesh lines converging at the proximal end 92 to form a spatial cone structure. The proximal end 92 is fixedly connected to the plug head 82, thereby fixing the capture part 100 of the filter to the distal side of the sealing part 80.

[0047] The distal filter 931 includes multiple interconnected first Y-shaped units 931a. Each first Y-shaped unit 931a includes a first mesh line 9311 and two second mesh lines 9312 formed by branching off one end of the first mesh line 9311. The multiple first mesh lines 9311 of the multiple first Y-shaped units 931a converge at the distal end 91, thereby giving the distal filter 931 a spatial conical structure after the capture part 100 is naturally released. The ends of the second mesh lines 9312 of each first Y-shaped unit 931a that are away from the distal end 91 are connected to the support section 932.

[0048] The near-end filter 933 includes multiple interconnected second Y-shaped units 933a. Each second Y-shaped unit 933a includes a third mesh line 9331 and two fourth mesh lines 9332 formed by branching off one end of the third mesh line. The multiple third mesh lines 9331 of the multiple second Y-shaped units 933a converge at the near end 92. Thus, when the capturing part 100 is naturally released, the near-end filter 933 has a spatial conical structure. The ends of the fourth mesh lines 9332 of each second Y-shaped unit 933a that are away from the near end 92 are connected to the support section 932.

[0049] The filter has an overall asymmetrical structure. For the distal filter 931, the two adjacent second mesh lines 9312 of its adjacent first Y-shaped unit 931a converge at the ends to form a single mesh line and are connected to the same support rod 932a. For the proximal filter 933, the two adjacent fourth mesh lines 9332 of its adjacent second Y-shaped unit 933a do not converge at the ends, but are connected to different support rods 932a respectively. Therefore, the number of first Y-shaped units 931a in the distal filter 931 is twice the number of second Y-shaped units 933a in the proximal filter 933, meaning the mesh structure density of the distal filter 931 is greater than that of the proximal filter 933.

[0050] When the thrombolytic catheter 1 needs to infuse thrombolytic solution into a thrombus-containing area of ​​the blood vessel, the occlusion section 80 retracts into the lumen of the external catheter 10 to achieve occlusion, while the capture section 100 is located outside the external catheter 10 and is in a naturally extended state. When the thrombus detaches from the blood vessel wall and becomes a free thrombus due to the dissolution and impact of the thrombolytic solution, it will move with the blood towards the capture section 100. Because the distal filter 931 and the proximal filter 933 adopt an asymmetrical structure, by setting appropriately sized mesh openings, they are selective for pre-filtered thrombi, ensuring both thrombus capture and vascular patency.

[0051] The embodiments described above are merely examples of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. The protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A thrombolytic catheter, characterized in that, include: An external catheter has a main tube, and the distal end of the main tube has an infusion section, the infusion section having a plurality of infusion holes spaced apart along the axial direction; An inner tube has a tube body that slides through the main tube to selectively cover at least part of the injection hole, thereby adjusting the effective length of the injection interval. The core rod is slidably inserted into the inner push tube and the outer guide tube; The occluder includes a capture part located on the distal side and an occlusion part located on the proximal side, which are connected to each other. The distal end of the core rod is fixedly connected to the proximal end of the occlusion part. When the occlusion part retracts to the distal end of the lumen of the external catheter to block the distal opening of the external catheter, the capture part can be located outside the external catheter and is in a natural state.

2. The thrombolytic catheter according to claim 1, characterized in that, The blocking part is provided with a first flow-blocking membrane, and / or the capturing part is provided with a second flow-blocking membrane.

3. The thrombolytic catheter according to claim 1, characterized in that, In its natural state, the thickness of the blocking part is greater than the thickness of the capturing part, and / or the diameter of the blocking part is smaller than the diameter of the capturing part.

4. The thrombolytic catheter according to claim 1, characterized in that, In its natural state, the outer periphery of the sealing part has a groove, or the shape of the capturing part is substantially the same as that of the sealing part.

5. The thrombolytic catheter according to any one of claims 1-4, characterized in that, The sealing part includes a sealing disc woven from braided yarn, and a connecting nut that connects to the core rod is provided on the proximal side of the sealing disc.

6. The thrombolytic catheter according to claim 5, characterized in that, The capturing part includes a capturing disc woven from braided filaments; or, the capturing part includes a filter composed of mesh wires, the filter including a distal end, a distal filter screen, a support section, a proximal filter screen and a proximal end connected in sequence from the distal end to the proximal end, the distal filter screen and the proximal filter screen are both spatial conical structures composed of multiple mesh wires, and the proximal end is fixedly connected to the distal side of the sealing disc.

7. The thrombolytic catheter according to claim 6, characterized in that, The density of the mesh structure of the distal filter is greater than the density of the mesh structure of the proximal filter.

8. The thrombolytic catheter according to claim 1, characterized in that, A first developing ring is provided on the distal end of the main tube, and a second developing ring is provided on the distal end of the tube body.

9. The thrombolytic catheter according to claim 1, characterized in that, The proximal end of the inner push tube is provided with a three-way hemostatic valve communicating with it. The proximal end of the core rod can pass through the three-way hemostatic valve and extend into the inner push tube. The three-way hemostatic valve can be clearance-fitted or interference-fitted with the core rod.

10. The thrombolytic catheter according to claim 1, characterized in that, A sealing ring is also provided on the outer periphery of the distal end of the tube, and the sealing ring slides and seals with the inner wall of the outer conduit.

11. The thrombolytic catheter according to claim 1, characterized in that, The outer diameter of the tube is 85%-95% of the inner diameter of the main tube.

12. The thrombolytic catheter according to claim 1, characterized in that, An indicator mark is provided on the proximal outer periphery of the inner push tube, the indicator mark being used to mark the relative position of the inner push tube relative to the outer catheter.

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