A pulmonary artery thrombus aspiration catheter and its manufacturing method

Abstract

This invention discloses a pulmonary artery thrombosis aspiration catheter and its manufacturing method, belonging to the field of medical device technology. The pulmonary artery thrombosis aspiration catheter includes a catheter body, a catheter tip, and a skirt structure. The catheter tip is dome-shaped and located at the distal end of the catheter body. The catheter tip is flexible, and a pre-incision is provided at the top of the distal end. The skirt structure includes a self-expanding skeleton and a covering membrane located around the self-expanding skeleton. The self-expanding skeleton is elastic and can be radially constrained and contracted. After release from constraint, it automatically expands radially into a trumpet shape. The proximal end of the self-expanding skeleton is connected to the catheter body. When the distal end of the skirt structure is contracted, it is located inside the catheter tip, and the pre-incision is closed. When the distal end of the skirt structure expands, it can open the catheter tip, allowing the pre-incision to open and form at least two leaflets. The distal edge of the pre-incision does not extend beyond the distal edge of the skirt structure. There is a gap between adjacent leaflets and the skirt structure, which can reduce damage to the tricuspid valve and other parts.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a pulmonary artery thrombosis aspiration catheter and its manufacturing method. Background Technology

[0002] In current pulmonary thrombosis treatment, a guidewire is advanced to the location of the lesion. Then, an aspiration catheter is used in conjunction with an inner / intermediate catheter, guiding the aspiration catheter along the path from the tricuspid valve / right ventricle to the main pulmonary artery to the lesion. Once the aspiration catheter is in place, the auxiliary inner / intermediate catheter is withdrawn, and a negative pressure suction device is used to aspirate the thrombus.

[0003] In related technologies, aspiration catheters have the following problems: First, the distal end of the aspiration catheter has poor flexibility, easily scratching the heart valves and vascular endothelium when passing through areas such as the tricuspid valve / right ventricle, thus inducing vasospasm or minor bleeding, and even right ventricular stimulation inducing arrhythmias; Second, pulmonary thrombi are generally large thrombi, which easily adhere to the inlet of the aspiration catheter tip, forming a "mouthpiece," causing momentary blockage. At this time, the negative pressure will decrease due to the blockage, resulting in obstructed negative pressure conduction and inability to aspirate the thrombus; at the same time, the blockage will further cause insufficient aspiration flow, and the adhesion between the aspiration catheter and the thrombus will also cause difficulty in withdrawal. In clinical practice, to solve this problem, it is necessary to frequently pull / retract the aspiration catheter to clear the blockage, which leads to longer operation time and increased blood loss. Summary of the Invention

[0004] The purpose of this invention is to provide a pulmonary artery thrombosis aspiration catheter and its manufacturing method, which improves the flexibility of the distal end of the aspiration catheter, reduces damage to the tricuspid valve and other parts, solves the problem of inlet blockage, and improves aspiration efficiency.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] A pulmonary thrombus aspiration catheter, comprising:

[0007] Catheter body;

[0008] The catheter tip is dome-shaped and located at the distal end of the catheter body. The catheter tip is flexible and has a pre-cut at the top of the distal end.

[0009] The skirt structure includes a self-expanding skeleton and a covering film disposed around the self-expanding skeleton. The self-expanding skeleton is elastic and can be constrained and contracted in the radial direction. After the constraint is released, it automatically expands in the radial direction into a trumpet shape.

[0010] The proximal end of the self-expanding skeleton is connected to the inner hole of the catheter body. When the distal end of the skirt structure is closed, it is located inside the catheter tip, and the pre-incision is closed. When the distal end of the skirt structure is expanded, it can open the catheter tip, so that the pre-incision is opened and forms at least two leaflets. The distal edge of the pre-incision does not extend beyond the distal edge of the skirt structure, and there is a gap between adjacent leaflets and the skirt structure.

[0011] In some embodiments, the proximal end of the membrane is provided with at least one first pressure relief hole along the periphery of the skirt structure, the diameter of the first pressure relief hole being 0.2mm-0.4mm; or, the distal end of the catheter body is provided with at least one second pressure relief hole along the periphery of the catheter body, the diameter of the second pressure relief hole being 0.2mm-0.4mm.

[0012] In some embodiments, the catheter tip includes a spherical crown and a plurality of ribs supported on the spherical crown. One end of the plurality of ribs converges at the central apex of the spherical crown, and the other end is radially and evenly distributed along the inner surface of the spherical crown. The spherical crown is provided with the pre-cut.

[0013] In some embodiments, the ribs are honeycomb-shaped; the thickness of the ribs in the middle is less than the thickness of the two ends along their length.

[0014] In some embodiments, the catheter tip forms multiple weakened tangents, which radiate outward from the central apex of the catheter tip, forming the pre-incision.

[0015] In some embodiments, the coating is an ePTFE membrane or a TPU membrane with a thickness of 0.05 mm to 0.10 mm, and the coating covers the self-expanding skeleton.

[0016] In some embodiments, the self-expanding skeleton is made of memory material, and the preset shape of the self-expanding skeleton is funnel-shaped. The outer diameter of the opening of the self-expanding skeleton in the unfolded state is 2 to 4 times the inner diameter of the conduit body.

[0017] In some embodiments, the device further includes a sheath spaced outside the catheter body, the distal end of the sheath extending to the periphery of the catheter tip to radially compress the skirt structure; the distal end of the sheath retracting to expose the catheter tip to the outside.

[0018] In some embodiments, the device further includes a constraint wire and a handle connected to the proximal end of the catheter body. The middle region of the constraint wire rotates around the distal end of the skirt structure to form a collar fitted onto the skirt structure. One end of the constraint wire is a fixed end, and the other end is a free end. The free end is placed on the handle. By tightening or loosening the free end, the skirt structure is disengaged from the collar, thereby unfolding the skirt structure.

[0019] A method for manufacturing a pulmonary thrombus aspiration catheter as described in any of the preceding claims, comprising:

[0020] A shape memory material is used to form a self-expanding skeleton, and a film is applied to the self-expanding skeleton by hot pressing to form a skirt structure; the self-expanding skeleton is connected to the main body of the conduit.

[0021] A spherical crown is formed by hot bulging using materials with a first preset hardness and materials with a second preset hardness. The material with the first preset hardness is placed near the edge, and the material with the second preset hardness is placed near the top. The first preset hardness is less than the second preset hardness. Multiple ribs are pressed into the spherical crown by hot pressing. One end of the multiple ribs converges at the central apex of the spherical crown, and the other end is evenly distributed radially along the inner surface of the spherical crown to form the head end of the conduit. Multiple weakened tangent lines are formed at the top of the spherical crown, radiating outward from the central apex. The head end of the conduit is connected to the conduit body.

[0022] The beneficial effects of this invention are:

[0023] This invention provides a pulmonary thrombus aspiration catheter and its manufacturing method. By designing the skirt structure as a retractable / expandable structure, in the delivery state, the skirt structure is constrained and retracted within the catheter tip, and the pre-cut opening is closed. Because the catheter tip is designed with a flexible dome-shaped structure, it can flexibly deform and slide over areas such as the tricuspid valve, rather than impacting them hard. This allows it to smoothly pass through the complex cardiac anatomy, reducing damage to the tricuspid and pulmonary valves and improving the safety of transvalvular aspiration. When the aspiration catheter reaches the target thrombus location, the constraint is released, causing the skirt structure to automatically expand radially and form a funnel-shaped structure. The skirt structure then opens the catheter tip, and the pre-cut opening is formed by the skirt structure, creating at least two leaflets. On one hand, the distal edge of the skirt structure forms a central inlet for thrombus aspiration, allowing the thrombus to pass through the skirt structure and enter the inner pore of the catheter body. On the other hand, gaps exist between adjacent leaflets and the skirt structure, ensuring that the distal edge of the pre-cut does not extend beyond the distal edge of the skirt structure, thus guaranteeing complete opening of the gaps without fluid obstruction. These gaps, located around the skirt structure, form auxiliary inlets for thrombus aspiration. The skirt structure forms bypass channels with the catheter body and catheter tip, respectively, and these bypass channels communicate with the auxiliary inlets. When the central inlet is blocked by thrombus adhesion, negative pressure can continue to act on the sides of the thrombus through the bypass channels and auxiliary inlets, "scraping" and aspirating it, breaking the "mouthpiece" effect and achieving continuous and efficient thrombus removal. The skirt structure provides an additional, surrounding aspiration path for the thrombus, effectively solving the inlet blockage problem and enabling multi-angle, high-efficiency aspiration of the thrombus. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the pulmonary artery thrombosis aspiration catheter in the delivery state provided by a specific embodiment of the present invention;

[0025] Figure 2 yes Figure 1 A magnified view of part A;

[0026] Figure 3 This is a front view of the catheter tip provided in a specific embodiment of the present invention;

[0027] Figure 4 This is a schematic diagram of the end face of the catheter tip provided in a specific embodiment of the present invention;

[0028] Figure 5 This is a schematic diagram of the reinforcing bars provided in a specific embodiment of the present invention;

[0029] Figure 6 This is a schematic diagram of the skirt structure in a gathered state according to a specific embodiment of the present invention;

[0030] Figure 7This is a schematic diagram of the skirt structure in its unfolded state according to a specific embodiment of the present invention;

[0031] Figure 8 This is a schematic diagram of the skirt structure with a first pressure relief hole provided in a specific embodiment of the present invention;

[0032] Figure 9 This is a schematic diagram of a conduit body with a second pressure relief hole provided in a specific embodiment of the present invention;

[0033] Figure 10 This is a schematic diagram of the constraint wire used for gathering the skirt structure according to a specific embodiment of the present invention;

[0034] Figure 11 This is a schematic diagram of the pulmonary thrombosis aspiration catheter being withdrawn from its sheath during delivery, provided in a specific embodiment of the present invention;

[0035] Figure 12 This is a flowchart illustrating the method for manufacturing a pulmonary artery thrombosis aspiration catheter according to a specific embodiment of the present invention.

[0036] In the picture:

[0037] 1. Catheter body; 11. Inner bore; 12. Guidewire lumen; 13. Second pressure relief port;

[0038] 2. Catheter tip; 21. Pre-incision; 22. Crown; 23. Rib; 231. Thin area;

[0039] 3. Skirt structure; 31. Self-expanding skeleton; 32. Coating; 321. First pressure relief hole;

[0040] 4. Sheath;

[0041] 5. Constraint wire; 51. Collar; 52. Fixed end; 53. Free end;

[0042] 6. Handle; 7. Release tube; 8. Control block;

[0043] 10. Guidewire; 20. Gap; 30. Central entrance; 40. Vessel wall; 50. Tricuspid valve; 60. Pulmonary valve; 70. Aspiration catheter. Detailed Implementation

[0044] To make the technical problems solved by the present invention, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0046] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0047] like Figures 1-11 As shown, this embodiment provides a pulmonary artery thrombosis aspiration catheter 70, including a catheter body 1, a catheter tip 2, and a skirt structure 3. The catheter tip 2 is dome-shaped and located at the distal end of the catheter body 1. The catheter tip 2 is flexible, and a pre-cut 21 is provided at the top of the distal end. The skirt structure 3 includes a self-expanding skeleton 31 and a membrane 32 disposed around the self-expanding skeleton 31. The self-expanding skeleton 31 is elastic and can be constrained and retracted radially. After the constraint is released, it automatically expands radially into a trumpet shape. The proximal end of the self-expanding skeleton 31 is connected to the inner hole 11 of the catheter body 1. When the distal end of the skirt structure 3 is retracted, it is located inside the catheter tip 2, and the pre-cut 21 is closed. When the distal end of the skirt structure 3 is expanded, it can open the catheter tip 2, so that the pre-cut 21 is opened and forms at least two leaflets. The distal edge of the pre-cut 21 does not extend beyond the distal edge of the skirt structure 3, and there is a gap 20 between adjacent leaflets and the skirt structure 3.

[0048] It should be noted that "proximal" usually refers to the end of the medical device that is closest to the operator during normal operation, while "distal" usually refers to the end of the medical device that first enters the patient's body during normal operation.

[0049] By configuring the skirt structure 3 as a retractable / expandable structure, in the delivery state, the skirt structure 3 is constrained and retracted within the catheter tip 2, and the pre-incision 21 is closed. Because the catheter tip 2 is configured as a flexible dome-shaped structure, it can undergo flexible deformation and slide over areas such as the tricuspid valve 50, rather than impacting them hard. This allows it to smoothly pass through the complex cardiac anatomy, reducing damage to the tricuspid valve 50 and pulmonary valve 60 and improving the safety of transvalvular access. When the aspiration catheter 70 reaches the target thrombus location, the constraint is released, causing the skirt structure 3 to automatically expand radially and form a funnel-shaped structure. The skirt structure 3 then opens the catheter tip 2, and the pre-incision 21 is opened by the skirt structure 3 to form at least two leaflets. On the one hand, the distal edge of the skirt structure 3 forms a central inlet 30 for thrombus aspiration, allowing the thrombus to pass through the skirt structure 3 and enter the inner hole 11 of the catheter body 1. On the other hand, there is a gap 20 between the adjacent leaflets and the skirt structure 3, and the distal edge of the pre-cut 21 does not extend beyond the distal edge of the skirt structure 3, thus ensuring that the gap 20 is completely open and free of fluid obstruction. This gap 20 is located around the skirt structure 3, forming an auxiliary inlet for thrombus aspiration. The skirt structure 3 forms bypass channels with the catheter body 1 and the catheter tip 2, respectively, and the bypass channels are connected to the auxiliary inlets. When the central inlet 30 is blocked by thrombus adhesion, negative pressure can continue to act on the side of the thrombus through the bypass channels and auxiliary inlets, "scraping" and aspirating it, breaking the "mouthpiece" effect and achieving continuous and efficient thrombus removal. The skirt structure 3 provides an additional aspiration path surrounding the thrombus, effectively solving the inlet blockage problem and achieving multi-angle, high-efficiency aspiration of the thrombus.

[0050] In one embodiment, the catheter body 1 is a polymer tubing with sufficient length, pushability, and flexural strength, with an outer diameter ranging from 2.7mm to 8.0mm, an inner diameter ranging from 2.3mm to 7.2mm, and an effective length ranging from 700mm to 1300mm. The proximal portion of the catheter body 1 uses a harder material, such as PEBAX (polyether block amide elastomer) with a hardness of 72D, to provide pushability, while the distal portion uses a softer material, such as PEBAX with a hardness of 35D, to enhance flexibility and achieve a gradual change in hardness. The catheter body 1 includes spaced-apart inner holes 11 and guidewire lumens 12. The guidewire lumens 12 are formed in the wall of the catheter body 1 and extend along the length of the catheter body 1. The distal inlet and proximal outlet of the guidewire lumens 12 are both located on the wall and are used to pass through the guidewire 10. The catheter body 1 is manufactured using a dual-lumen co-extrusion process, which is existing technology and will not be described in detail here. Specifically, there is only one guidewire lumen 12. The guidewire lumen 12 is used to pass through the 0.035-inch guidewire 10. After the guidewire 10 reaches the lesion site, the catheter body 1 is pushed along the guidewire 10 to reach the lesion site.

[0051] The inner hole 11 of the catheter body 1 forms the main working chamber. The distal end of the catheter body 1 is used to accommodate the compressed skirt structure 3 and connect to the catheter tip 2. The proximal end is connected to the suction pump interface, thereby forming a thrombus aspiration channel.

[0052] The catheter tip 2 includes a spherical crown 22 and multiple ribs 23 supported on the spherical crown 22. One end of the multiple ribs 23 converges at the central apex of the spherical crown 22, and the other end is evenly distributed radially along the inner surface of the spherical crown 22. The spherical crown 22 is provided with a pre-cut 21.

[0053] In one embodiment, the length of the catheter tip 2 ranges from 5mm to 10mm, increasing with the outer diameter of the catheter body 1, and the wall thickness is 0.15mm to 0.3mm. The ribs 23 have a honeycomb structure; along their length, the thickness x1 in the middle of the ribs 23 is less than the thickness x2 at both ends. For example, the middle area is a thinner region 231, which facilitates the formation of reversible wrinkles under pressure, allowing them to bend under resistance and return to their original shape with their own elasticity after the resistance disappears, thus improving flexibility; the ends maintain sufficient thickness to ensure support. Optionally, the width of the ribs 23 ranges from 0.15mm to 0.25mm, and the height ranges from 0.05mm to 0.10mm.

[0054] Multiple weakened tangent lines are formed at the catheter tip 2, radiating outward from the central apex of the catheter tip 2, forming a pre-incision 21. By setting the weakened tangent lines at preset positions, it is convenient to control the skirt structure 3 to open the pre-incision 21 with a preset force at a preset time and position. Specifically, the expansion force of the self-expanding skeleton 31 is greater than the cutting force of the pre-incision 21. Before opening the pre-incision 21, the catheter tip 2 maintains an intact structure, without affecting its flexibility. Optionally, the length of the pre-incision 21, starting from the central apex of the catheter tip 2, ranges from 3mm to 8mm, and the length can be set proportionally to the diameter of the catheter tip 2. Taking a number of pre-incisions 21 of 4 as an example, after the pre-incisions 21 are opened, four leaflets are formed, creating four slits 20 surrounding the skirt structure 3. By increasing the number of pre-incisions 21, the number of slits 20 is increased, thereby improving the effect of the auxiliary inlet on thrombus aspiration. In other embodiments, two, three, five or more weakened tangents may be provided to create a more uniform leaflet opening effect.

[0055] The spherical crown 22 is made of an ultra-soft, high-resilience material, such as low-hardness TPU (thermoplastic polyurethane) or silicone, with a Shore hardness transitioning from 25A-30A to 35A-40A from the edge to the top. Optionally, the catheter tip 2 is formed into a spherical crown 22 (spherical crown mold) by heat bulging, followed by a secondary heat pressing to insert 6-8 ribs 23, thereby setting the shape of the catheter tip 2 into a collapsible dome. Subsequently, four fine pre-cut notches 21 are formed by laser cutting or molding, radiating outward from the center point, with adjacent angles of approximately 90 degrees. Due to the relatively complex structure of the catheter tip 2, the distal end of the catheter body 1 is seamlessly connected to the catheter tip 2 by bonding or heat fusion, which facilitates the fabrication of the catheter tip 2 and the catheter body 1. In other embodiments, the two can also be an integral structure.

[0056] The coating 32 is an ePTFE (Expanded Polytetrafluoroethylene) film or a TPU film with a thickness of 0.05mm-0.10mm. The coating 32 is applied to the self-expanding skeleton 31 through industrial processes such as thermal lamination. The ePTFE and TPU materials have good biocompatibility.

[0057] The self-expanding skeleton 31 is made of shape memory material. Its preset shape is a funnel shape. In the delivery state, the skirt structure 3 is constrained and closed, tightly adhering to the inner wall of the catheter body 1. When the aspiration catheter 70 reaches the target thrombus location and the constraint is released, the skirt structure 3 expands radially under the shape memory effect, forming a funnel-shaped structure. The outer diameter of the opening of the self-expanding skeleton 31 in the expanded state is 2 to 4 times the inner diameter of the catheter body 1. The thickness of the self-expanding skeleton 31 ranges from 0.15 mm to 0.25 mm, and its expansion force is the power source for opening the pre-cut incision 21. Optionally, the shape memory material, such as a superelastic nickel-titanium alloy, is made by laser-cutting a nickel-titanium alloy tube, preset to a funnel shape, and can recover after compression; or it is made of a shape memory polymer material, whose glass transition temperature (Tg) can be set slightly lower than the human body temperature so that expansion is achieved through heat absorption within the body.

[0058] The proximal end of the self-expanding skeleton 31 is fixed to the distal inner wall of the inner hole 11 of the catheter body 1 by injection molding. Most of its "expandable section" is compressed and accommodated in the internal cavity of the catheter tip 2 during delivery. The length of the skirt structure 3 ranges from 3mm to 8mm. In the unexpanded state, the difference between the longitudinal length of the skirt structure 3 and the longitudinal length of the catheter tip 2 is less than 2mm. In the retracted state, the catheter tip 2 can completely encapsulate the compressed skirt structure 3. In the expanded state, the pre-cut 21 is opened to form multiple leaflets, the ends of which are configured not to exceed the distal edge of the skirt structure 3. Optionally, the catheter tip 2 is connected to the end of the catheter body 1, and the skirt structure 3 is connected to the inner wall of the catheter body 1.

[0059] like Figure 7 As shown, in one embodiment, there is no connection between the diaphragm 32 and the inner wall of the catheter body 1. The diaphragm 32 forms an aspiration surface, and at least one first pressure relief hole 321 is provided at the proximal end of the diaphragm 32 along the periphery of the skirt structure 3. The diameter of the first pressure relief hole 321 is 0.2mm-0.4mm. When both the central inlet 30 and the auxiliary inlet are rarely completely blocked by thrombi, the fluid (blood) between the aspiration catheter 70 and the vessel wall 40 can still enter between the skirt structure 3 and the leaflets, and then enter the catheter body 1 through the first pressure relief hole 321. This maintains a low but crucial fluid permeability, enabling rapid pressure relief, thereby breaking the formation of a vacuum, preventing system vacuum lock-up, ensuring the balance of internal system pressure, and allowing the aspiration catheter 70 to always be safely moved and adjusted, improving the controllability and safety of the surgery. Exemplarily, the diaphragm 32 has eight first pressure relief holes 321 evenly spaced along the periphery of the skirt structure 3, with a diameter of 0.3mm.

[0060] like Figure 8 As shown, in one embodiment, at least one second pressure relief hole 13 is provided at the distal end of the catheter body 1 along its circumference, and the diameter of the second pressure relief hole 13 is 0.2mm-0.4mm; exemplaryly, 10 second pressure relief holes 13 with a diameter of 0.2mm are evenly spaced along the circumference of the catheter body 1. When both the central inlet 30 and the auxiliary inlet are rarely completely blocked by thrombus, the fluid (blood) between the catheter body 1 and the vessel wall 40 directly enters the catheter body 1 through the second pressure relief hole 13, maintaining a low but crucial fluid permeability, enabling rapid pressure relief, thereby breaking the formation of a vacuum, avoiding system vacuum lock-up, ensuring the balance of internal system pressure, and allowing the aspiration catheter 70 to always be safely moved and adjusted, improving the controllability and safety of the surgery.

[0061] The pulmonary thrombosis aspiration catheter 70 also includes a sheath 4, which is spaced outside the catheter body 1. The distal end of the sheath 4 can extend to the periphery of the catheter tip 2, radially compressing the skirt structure 3. The distal end of the sheath 4 can retract to expose the catheter tip 2 to the outside. In the delivery state of the aspiration catheter 70, the distal end of the sheath 4 extends to the catheter tip 2, providing protection. Additionally, the mechanical compression of the skirt structure 3 from the periphery provides primary compression constraint, preventing premature expansion and thus preventing premature rupture of the pre-incision 21. In one embodiment, the sheath 4 is a thin-walled polymer tube with an inner diameter 0.5mm-1.0mm larger than the outer diameter of the catheter body 1, and a wall thickness ranging from 0.15mm to 0.25mm. Optionally, the proximal end of the catheter body 1 is provided with a locking mechanism or graduation markings to precisely control the retraction and forward movement of the sheath 4 and ensure its stability during delivery. Specific details are available in existing technology and will not be elaborated further.

[0062] The pulmonary thrombosis aspiration catheter 70 also includes a restraining wire 5 and a handle 6 connected to the proximal end of the catheter body 1. The middle region of the restraining wire 5 rotates around the distal end of the skirt structure 3 to form a collar 51 fitted onto the skirt structure 3. One end of the restraining wire 5 is a fixed end 52, and the other end is a free end 53, which is placed on the handle 6. By tightening or loosening the free end 53, the skirt structure 3 is disengaged from the collar 51, thereby unfolding the skirt structure 3. The restraining wire 5 is used to directly restrain the skirt structure 3; it is very thin but extremely strong, and its material includes, but is not limited to, polypropylene sutures or super-elastic nickel-titanium wire. The constraint wire 5 is folded back to form a collar 51 at the distal end and a fixed end 52 and a free end 53 at the proximal end, forming a constraint loop. The constraint wire 5 passes through a release tube 7 fixed to the distal end of the catheter body 1, and its distal end is bound to the compressed skirt structure 3 by the collar 51. The fixed end 52 at the proximal end is connected to the handle 6 at the proximal end of the catheter body 1. A control block 8 is provided in the handle 6, and the free end 53 is connected to the control block 8. In one embodiment, by rotating the control block 8 counterclockwise, the free end 53 is tightened, that is, the constraint loop is tightened, and the skirt structure 3 is kept in a compressed state. By rotating the control block 8 clockwise, the free end 53 is released, that is, the constraint loop is released, the constraint force of the collar 51 from the proximal end disappears, and the skirt structure 3 is released from constraint. In another embodiment, since the self-expanding skeleton 31 has an expansion tendency, it has an expansion force. The greater the expansion force, the greater the initial tension of the constraint wire 5, and the smaller the additional tensile force required to achieve breakage. By rotating the control block 8 counterclockwise to tighten the free end 53, i.e., pulling the collar 51, the collar 51 breaks when the tensile stress inside exceeds the material's strength limit, thereby releasing the constraint of the skirt structure 3. The control block 8 is rotatably connected to the handle 6; the specific connection structure can be referred to in the prior art and will not be described in detail here.

[0063] This embodiment also provides a method for using the above-mentioned pulmonary artery thrombosis aspiration catheter 70, including the following steps:

[0064] Delivery Phase: The aspiration catheter 70 is in its assembled delivery state. The skirt structure 3 is bound and compressed to the distal end of the catheter body 1 by the restraint wire 5, and is externally covered and protected by the sheath 4. Intravenous access is established, and a standard guidewire 10 is inserted into the target pulmonary artery. The proximal end of the guidewire 10 is inserted through the distal inlet of the guidewire lumen 12 and exits through its proximal outlet. The aspiration catheter 70 is advanced along the guidewire 10 to the right atrium, about to pass through the tricuspid valve 50.

[0065] Safe transvalvular crossing phase: Secure the catheter body 1, retract the sheath 4 posteriorly to expose the catheter tip 2. At this time, the restraint wire 5 is still in operation, the skirt structure 3 is restrained and retracted without unfolding, and the pre-incision 21 closes due to elasticity. Then, use the exposed catheter tip 2 to safely pass through the tricuspid valve 50 and the pulmonary valve 60.

[0066] Deployment Phase: Upon reaching the vicinity of the pulmonary thrombus, the restraint wire 5 is released and withdrawn, causing the skirt structure 3 to lose its final restraint. The self-expanding skeleton 31 immediately restores its preset trumpet-shaped memory shape and expands radially outward. The self-expanding skeleton 31 and its covering membrane 32 push outward to open the leaflets of the pre-incision 21, changing it from a closed state to an open state, forming a central entrance 30 and multiple auxiliary entrances.

[0067] Aspiration stage: Withdraw the guidewire 10, connect the proximal end of the catheter body 1 to the negative pressure aspiration device (such as a syringe or vacuum pump), then start the negative pressure, and the suction force is transmitted to the distal end through the inner hole 11 of the aspiration catheter 70.

[0068] In the first case, thrombus material can be aspirated through the central inlet 30.

[0069] In the second scenario, the central inlet 30 is blocked by thrombus material, but the negative pressure within the inner orifice 11 does not disappear. In this case, the fluid (blood) flows along the path of least resistance. Because the auxiliary inlet, formed by the unfolded skirt structure 3 and the catheter tip 2, surrounds the side of the thrombus, it immediately becomes a new, lower-resistance fluid path. The suction negative pressure is instantly redistributed, and the main load shifts to the auxiliary inlet. Like using a very gentle "ring scraper," the thrombus is scraped and peeled off layer by layer from the periphery to the center. The scraped-off thrombus fragments are immediately drawn into the annular side gap formed by the skirt structure 3 and the catheter tip 2, entering the inner orifice 11. As long as the auxiliary inlet remains unobstructed, this process continues, constantly "digesting" the thrombus body blocking the central inlet 30, thus effectively avoiding the "mouthpiece" effect and significantly improving suction efficiency.

[0070] In the third scenario, both the central inlet 30 and the auxiliary inlet are completely blocked. Blood can enter the inner hole 11 through the first pressure relief hole 321 and / or the second pressure relief hole 13 opened in the skirt structure 3, maintaining a basic fluid flow rate and preventing the catheter body 1 from being "welded" to the blood vessel wall 40 by absolute vacuum. Furthermore, the operator or physician can safely and slightly push or rotate the catheter forward to change its contact surface with the thrombus, break the complete blockage, and restore the ring scraping and suction mechanism to work.

[0071] Retrieval Phase: After thrombus aspiration is complete, negative pressure is stopped. The operator pushes the sheath 4 distally, gradually covering and compressing the unfolded skirt structure 3. This causes it to retract, and the leaflets at the catheter tip 2 close accordingly. The entire aspiration catheter 70 can then be safely withdrawn from the body without damaging the valves during withdrawal. Through these steps, efficient and safe thrombus aspiration is achieved.

[0072] like Figure 12As shown, this embodiment also provides a method for manufacturing the pulmonary thrombus aspiration catheter 70 as described above, including:

[0073] A self-expanding skeleton 31 is formed using shape memory material, and a coating 32 is applied to the self-expanding skeleton 31 by hot pressing to form a skirt structure 3; the self-expanding skeleton 31 is connected to the conduit body 1 by means of bonding, etc.

[0074] A spherical crown 22 is formed by heat-blowing using materials with a first preset hardness and materials with a second preset hardness. The material with the first preset hardness is positioned near the edge, and the material with the second preset hardness is positioned near the top. The first preset hardness is less than the second preset hardness. Multiple ribs 23 are pressed into the spherical crown 22 by heat pressing. One end of the multiple ribs 23 converges at the central apex of the spherical crown 22, and the other end is evenly distributed radially along the inner surface of the spherical crown 22 to form the conduit head 2. Multiple weakened tangent lines radiating outward from the central apex are formed at the top of the spherical crown 22. The conduit head 2 is connected to the conduit body 1 by means of bonding or other methods. For example, the spherical crown 22 is made of ultra-soft, high-resilience, low-hardness TPU (thermoplastic polyurethane) or silicone materials, and its Shore hardness transitions from 25A-30A to 35A-40A from the edge to the top.

[0075] The skirt structure 3 is first connected inside the catheter body 1, and then the catheter tip 2 is connected to the catheter body 1 for easy operation.

[0076] Optionally, the skirt structure 3 and the catheter tip 2 are fabricated first, and then connected to the catheter body 1 in sequence. Alternatively, the skirt structure 3 is fabricated first and connected to the catheter body 1, and then the catheter tip 2 is fabricated and connected to the catheter body 1. The specific process is not limited.

[0077] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A pulmonary artery thrombus aspiration catheter, characterized in that, include: Catheter body (1); The catheter tip (2) is dome-shaped and located at the distal end of the catheter body (1). The catheter tip (2) is flexible and has a pre-cut (21) at the top of the distal end. The skirt structure (3) includes a self-expanding skeleton (31) and a covering film (32) disposed on the periphery of the self-expanding skeleton (31). The self-expanding skeleton (31) is elastic and can be constrained and folded in the radial direction. After the constraint is released, it automatically unfolds in the radial direction into a trumpet shape. The proximal end of the self-expanding skeleton (31) is connected to the inner hole (11) of the catheter body (1). When the distal end of the skirt structure (3) is closed, it is located inside the catheter tip (2), and the pre-incision (21) is closed. When the distal end of the skirt structure (3) is expanded, it can open the catheter tip (2), so that the pre-incision (21) is opened and forms at least two leaflets. The distal edge of the pre-incision (21) does not extend beyond the distal edge of the skirt structure (3), and there is a gap (20) between the adjacent leaflets and the skirt structure (3).

2. The pulmonary thrombus aspiration catheter according to claim 1, characterized in that, The proximal end of the membrane (32) is provided with at least one first pressure relief hole (321) along the periphery of the skirt structure (3), and the diameter of the first pressure relief hole (321) is 0.2mm-0.4mm; or, the distal end of the catheter body (1) is provided with at least one second pressure relief hole (13) along the periphery of the catheter body (1), and the diameter of the second pressure relief hole (13) is 0.2mm-0.4mm.

3. The pulmonary thrombus aspiration catheter according to claim 1, characterized in that, The catheter tip (2) includes a spherical crown (22) and a plurality of ribs (23) supported on the spherical crown (22). One end of the plurality of ribs (23) converges at the central apex of the spherical crown (22), and the other end is radially and evenly distributed along the inner surface of the spherical crown (22). The spherical crown (22) is provided with the pre-cut (21).

4. The pulmonary thrombus aspiration catheter according to claim 3, characterized in that, The ribs (23) are honeycomb-shaped; the thickness of the ribs (23) in the middle is less than the thickness of the two ends along the length direction.

5. The pulmonary thrombus aspiration catheter according to claim 1, characterized in that, The catheter tip (2) forms multiple weakened tangents, which radiate outward from the central apex of the catheter tip (2) and form the pre-cut (21).

6. The pulmonary thrombus aspiration catheter according to claim 1, characterized in that, The coating (32) is an ePTFE film or a TPU film with a thickness of 0.05mm-0.10mm, and the coating (32) covers the self-expanding skeleton (31).

7. The pulmonary thrombus aspiration catheter according to claim 1, characterized in that, The self-expanding skeleton (31) is made of memory material. The preset shape of the self-expanding skeleton (31) is a trumpet shape. The outer diameter of the opening of the self-expanding skeleton (31) in the unfolded state is 2 to 4 times the inner diameter of the conduit body (1).

8. The pulmonary thrombus aspiration catheter according to claim 1, characterized in that, It also includes a sheath (4), which is spaced outside the catheter body (1). The distal end of the sheath (4) can extend to the periphery of the catheter tip (2) and radially compress the skirt structure (3). The distal end of the sheath (4) can be retracted to expose the catheter tip (2) to the outside.

9. The pulmonary thrombus aspiration catheter according to claim 1, characterized in that, It also includes a constraint wire (5) and a handle (6) connected to the proximal end of the catheter body (1). The middle region of the constraint wire (5) rotates around the distal end of the skirt structure (3) to form a collar (51) fitted onto the skirt structure (3). One end of the constraint wire (5) is a fixed end (52), and the other end is a free end (53). The free end (53) is placed on the handle (6). By tightening or loosening the free end (53), the skirt structure (3) is disengaged from the collar (51), thereby unfolding the skirt structure (3).

10. A method for manufacturing a pulmonary artery thrombus aspiration catheter as described in any one of claims 1-9, characterized in that, include: A self-expanding skeleton (31) is formed using shape memory material, and a coating (32) is applied to the self-expanding skeleton (31) by hot pressing to form a skirt structure (3); the self-expanding skeleton (31) is connected to the conduit body (1); A spherical crown (22) is formed by hot bulging using materials with a first preset hardness and materials with a second preset hardness. The material with the first preset hardness is placed near the edge, and the material with the second preset hardness is placed near the top. The first preset hardness is less than the second preset hardness. Multiple ribs (23) are pressed into the spherical crown (22) by hot pressing. One end of the multiple ribs (23) converges at the central apex of the spherical crown (22), and the other end is evenly distributed radially along the inner surface of the spherical crown (22) to form a guide tube head (2). Multiple weakened tangent lines are formed at the top of the spherical crown (22) radiating outward from the central apex. The guide tube head (2) is connected to the guide tube body (1).

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