A suction catheter

Abstract

The present invention discloses a suction catheter, which belongs to the technical field of medical devices. The suction catheter includes a catheter assembly and a shearing piece, the catheter assembly includes an outer tube, an intermediate tube and an inner tube, the outer tube is sleeved on the intermediate tube to form a first suction cavity between the two, the inner tube has a second suction cavity, the intermediate tube is sleeved on the inner tube to form a shearing cavity between the two, the proximal ends of the outer tube and the inner tube are connected to a vacuum source, so that the first suction cavity and the second suction cavity respectively form negative pressure for suctioning thrombus, and the pressure of the second suction cavity is not less than the pressure of the first suction cavity, and the shearing piece is arranged at the distal end of the catheter assembly; after the second suction cavity sucks the thrombus, the shearing piece can shear the thrombus located outside the second suction cavity, without withdrawing the suction catheter out of the body, reducing the surgical risk and preventing the thrombus from escaping and falling off.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a suction catheter. Background Art

[0002] At present, when aspirating thrombus, it is necessary to insert the aspiration catheter into the treatment blood vessel, and use the negative pressure of the self-priming pump or handheld syringe to extract the thrombus in the blood vessel. With the uninterrupted operation of the self-priming pump, the thrombus in the blood vessel can be continuously extracted to achieve the purpose of removing the thrombus.

[0003] When aspirating large hard thrombi and mixed thrombi, the distal end of the aspiration catheter is prone to blockage due to the difficulty in separating such thrombi. At this time, the aspiration catheter can only be withdrawn, unblocked, and pushed back to the original position to continue aspiration. However, withdrawing the aspiration catheter will prolong the operation time and increase the risk of surgery. On the other hand, there is a risk of thrombus detachment during the withdrawal of the aspiration catheter. Summary of the invention

[0004] The purpose of the present invention is to provide an aspiration catheter, which does not need to be withdrawn from the body, reduces the surgical risk, and prevents the thrombus from escaping and falling off.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] A suction catheter comprises a catheter assembly and a shearing piece, wherein the catheter assembly comprises an outer tube, an intermediate tube and an inner tube, the outer tube is sleeved on the intermediate tube to form a first suction cavity therebetween, the inner tube has a second suction cavity, the intermediate tube is sleeved on the inner tube to form a shearing cavity therebetween, the proximal ends of the outer tube and the inner tube are connected to a vacuum source so that the first suction cavity and the second suction cavity respectively form negative pressure for aspirating thrombus, and the pressure of the second suction cavity is not less than the pressure of the first suction cavity, and the shearing piece is arranged at the distal end of the catheter assembly; after the second suction cavity aspirates the thrombus, the shearing piece can shear the thrombus located outside the second suction cavity.

[0007] In some possible embodiments, the shearing piece includes at least two shearing parts, the shearing piece is connected to the middle tube, the inner tube can pass through the shearing piece and move back and forth; the shearing parts are elastic, when the inner tube passes through the shearing piece, the inner tube pushes the shearing parts to deform the shearing parts, and the shearing parts are located on the outer surface of the inner tube, when the inner tube retracts, the shearing parts are reset to the end of the inner tube, and two adjacent shearing parts are used to shear thrombus.

[0008] In some possible embodiments, the shearing piece is a first shearing piece, which is in the shape of a plate and is connected to the inner wall of the intermediate tube on all sides. A first incision and a second incision are respectively provided on two sides of the shearing piece, and the first incision and the second incision partially intersect. The first incision and the second incision are at the intersection and allow the inner tube to pass through on both sides of the shearing piece. The shearing parts are formed on both sides of the first incision and the second incision, respectively, and when the inner tube passes through the center position of the shearing piece, the shearing parts seal the outer surface of the inner tube; or, the shearing piece is a second shearing piece, which is in the shape of a plate and is connected to the inner wall of the intermediate tube on all sides. A third incision is provided on the shearing piece so that the inner tube can pass through on both sides of the shearing piece. The shearing parts are formed on both sides of the third incision, and when the inner tube passes through the third incision, a leakage port is formed between adjacent shearing parts and the outer surface of the inner tube.

[0009] In some possible embodiments, the proximal end of the intermediate tube is connected to a fluid supply device, and when the shearing piece is a first shearing piece, the fluid supply device is used to supply flushing fluid; when the shearing piece is a second shearing piece, the fluid supply device is used to supply thrombolytic drugs.

[0010] In some possible implementations, when the shearing member is the first shearing member, at t a -t b During the time period, the pressure of the second suction chamber is greater than the pressure of the first suction chamber, and at t a -T period, the liquid supply device supplies flushing liquid, at Tt b During the time period, the inner tube reciprocates to cause the shearing member to shear the thrombus, wherein t a <T<t b When the shearing member is the second shearing member, at t a -t b During the time period, the pressure of the second suction chamber is greater than the pressure of the first suction chamber, and the liquid supply device supplies thrombolytic drugs. b During the time period, the inner tube reciprocates to cause the shearing member to shear the thrombus, wherein t a <T<t b .

[0011] In some possible embodiments, when the shearing piece is a first shearing piece, when contrast fluid is injected into the inner tube, the proximal ends of the middle tube and the outer tube are closed; when the shearing piece is a second shearing piece, when contrast fluid is injected into the middle tube, the proximal ends of the inner tube and the outer tube are closed.

[0012] In some possible implementations, the inner tube aspirates thrombus intermittently or continuously; the outer tube aspirates thrombus intermittently or continuously.

[0013] In some possible implementations, the suction frequency of the outer tube is the same as the reciprocating frequency of the inner tube, and the outer tube aspirates the thrombus when the inner tube is withdrawn through the shear member.

[0014] In some possible implementations, the distal end of the outer tube is an oblique end or a straight end, and / or the distal end of the inner tube is an oblique end or a straight end.

[0015] In some possible implementations, the outer tube, the middle tube, and the inner tube all include a lubricating layer, a reinforcing layer, and a polymer layer arranged from the inside to the outside.

[0016] In some possible embodiments, the inner diameter of the outer tube is at least 0.1 mm larger than the outer diameter of the intermediate tube, and / or the inner diameter of the intermediate tube is at least 0.1 mm larger than the outer diameter of the inner tube, and / or the wall thickness of the intermediate tube is not greater than 0.5 mm, and / or the ratio of the inner diameter of the intermediate tube to the inner diameter of the outer tube is not less than 50%.

[0017] Beneficial effects of the present invention:

[0018] The present invention provides a suction catheter, wherein the second suction chamber sucks thrombus, the shearing piece shears the thrombus outside the second suction chamber, and the first suction chamber sucks the sheared external thrombus. The shearing piece can effectively shear the thrombus, reduce the volume of the thrombus, avoid the inner tube from blocking the tube, and the outer tube sucks the sheared thrombus, thereby improving the suction efficiency and reliability. Therefore, there is no need to withdraw the suction catheter from the body, thereby reducing the surgical risk, and the outer tube cooperates to capture the broken thrombus, thereby reducing the escape and shedding of the broken thrombus, thereby improving the suction efficiency and reliability. The pressure of the suction catheter can be adjusted, the suction pressure of the second suction chamber is increased, the suction pressure of the first suction chamber is reduced, and the shearing chamber does not provide suction pressure. Compared with a general thrombus suction catheter, by setting an inner tube, an intermediate tube and an outer tube, the number of catheters is increased, the suction area is reduced, and the suction pressure is reduced, thereby reducing blood loss and improving safety and reliability. In the face of a complex blood coagulation environment, both hard thrombus clots and soft thrombus clots can be sucked, thereby increasing the scope of application of the thrombus suction catheter and reducing the surgical risk of the patient. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is an axial cross-sectional view of the suction catheter provided in the first embodiment of the present invention;

[0020] Figure 2 is a radial cross-sectional view of the suction catheter provided in the first embodiment of the present invention;

[0021] Figure 3 is a schematic diagram of a first shearing member provided in Embodiment 1 of the present invention;

[0022] Figure 4 yes Figure 3 AA section view;

[0023] Figure 5 yes Figure 3 BB cross-sectional view;

[0024] Figure 6 is a schematic diagram of a state in which the inner tube of the suction catheter provided by the first embodiment of the present invention passes through a shearing piece;

[0025] Figure 7 This is a schematic diagram of the state before thrombus aspiration provided by the first embodiment of the present invention;

[0026] Figure 8 This is a schematic diagram of a state where a thrombus contacts and blocks a tube, provided in Embodiment 1 of the present invention;

[0027] Fig. 9 is a schematic diagram of the thrombus aspiration state provided by the first embodiment of the present invention;

[0028] Fig.10 This is a schematic diagram of the state of capturing and aspirating thrombus provided by the first embodiment of the present invention;

[0029] Fig.11 This is a schematic diagram of the thrombus shearing and flushing state provided by the first embodiment of the present invention;

[0030] Fig.12 is a schematic diagram of a suction working condition provided by the first embodiment of the present invention;

[0031] Fig.13 This is a schematic diagram of the working condition of aspirating soft thrombus provided in the first embodiment of the present invention;

[0032] Fig.14 is a schematic diagram of an outer tube provided in Embodiment 1 of the present invention;

[0033] Fig.15 is a schematic diagram of another outer tube provided in the first embodiment of the present invention;

[0034] Fig.16 is a schematic diagram of a second shearing member provided in Embodiment 2 of the present invention;

[0035] Fig.17 yes Fig.16 CC section view;

[0036] Fig.18 yes Fig.16 DD cross-sectional view;

[0037] Fig.19 This is a schematic diagram of the thrombolytic drug provided in the second embodiment of the present invention in the state of eroding thrombus and aspirating;

[0038] Fig. 20 It is a schematic diagram of the working condition of thrombolytic drugs eroding thrombus provided in the second embodiment of the present invention.

[0039] In the figure:

[0040] 1. Catheter assembly; 11. Outer tube; 111. Lubricating layer; 112. Reinforcement layer; 1121. Spring layer; 1122. Braided layer; 113. Polymer layer; 114. Oblique opening; 115. Straight opening; 12. Intermediate tube; 13. Inner tube; 1M. First suction chamber; 1N. Second suction chamber; 1P. Shearing chamber;

[0041] 2. Shearing piece; 21. First incision; 22. Second incision; 23. Third incision; 24. Shearing portion;

[0042] 3. Luer head; 4. Seal; 5. Cam;

[0043] 100. Thrombosis;

[0044] D. Aspiration direction; E. Flushing fluid flow direction; F. Thrombolytic drug flow direction. DETAILED DESCRIPTION

[0045] In order 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 in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0046] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0048] Embodiment 1

[0049] like Figure 1-Figure 11 As shown, Figure 9-11 All of them are schematic diagrams of thrombus aspiration, with the aspiration direction being D and the flushing fluid flow direction being E. The present embodiment provides a suction catheter, including a catheter assembly 1 and a shearing piece 2. The catheter assembly 1 includes an outer tube 11, an intermediate tube 12 and an inner tube 13. The outer tube 11 is sleeved on the intermediate tube 12 to form a first suction chamber 1M therebetween. The inner tube 13 has a second suction chamber 1N. The intermediate tube 12 is sleeved on the inner tube 13 to form a shearing chamber 1P therebetween. The proximal end of the intermediate tube 12 is connected to a liquid supply device. The proximal ends of the outer tube 11 and the inner tube 13 are both connected to a vacuum source. The inner tube 13 and the outer tube 11 can independently control suction, so that the first suction chamber 1M and the second suction chamber 1N respectively form negative pressure for suctioning thrombus 100, and the pressure of the second suction chamber 1N is not less than the pressure of the first suction chamber 1M. The shearing piece 2 is arranged at the distal end of the catheter assembly 1. After the second suction chamber 1N sucks the thrombus 100, the shearing piece 2 can shear the thrombus 100 located outside the second suction chamber 1N.

[0050] The term "proximal end" or "distal end" refers to a relative position relative to an operator. The position closer to the operator is the proximal end, and the position farther from the operator is the distal end.

[0051] The pressure of the suction catheter can be adjusted to increase the suction pressure of the second suction chamber 1N, reduce the suction pressure of the first suction chamber 1M, and the shear chamber 1P does not provide suction pressure. Compared with a general thrombus suction catheter, the number of catheters is increased by providing the inner tube 13, the middle tube 12 and the outer tube 11. Since the wall thickness of the middle tube 12 and the inner tube 13 occupies a space volume, the blood loss during the suction of the thrombus 100 is reduced, the suction area is reduced, and the suction pressure is reduced. Furthermore, since the pressure of the inner tube 13 when aspirating the thrombus 100 is greater than or equal to the pressure of the outer tube 11 when aspirating the thrombus 100, the outer tube 11 and the inner tube 13 use a stepped suction method, that is, the pressure of the inner tube 13 is greater than the pressure of the outer tube 11. On the one hand, it can prevent the escape of broken thrombus particles while ensuring the removal of the thrombus 100. On the other hand, it can minimize the amount of blood loss, because the inner tube 13 only needs to capture the thrombus 100 with a large suction force and then the auxiliary shearing piece 2 can separate the thrombus 100, and the outer tube 11 only needs to collect the escaped broken thrombus. The two have a synergistic effect, which reduces the dependence of a single suction catheter on the suction pressure.

[0052] The vacuum pressure of the first suction chamber 1M and the second suction chamber 1N are both greater than or equal to 67Kpa. The suction pressure of the suction catheter is limited by the vacuum pressure, and the negative pressure will not exceed 98Kpa. The pressure of the second suction chamber 1N is greater than the pressure of the first suction chamber 1M and at least 20Kpa greater. Preferably, the pressure of the second suction chamber 1N is 95Kpa, the pressure of the second suction chamber 1N is greater than the pressure of the first suction chamber 1M and 20Kpa greater, and the pressure of the first suction chamber 1M is 75Kpa.

[0053] The second suction chamber 1N sucks the thrombus 100, the shearing piece 2 shears the thrombus 100 outside the second suction chamber 1N, and the first suction chamber 1M sucks the sheared external thrombus 100. The shearing piece 2 can effectively shear the thrombus 100, reduce the volume of the thrombus 100, and avoid the inner tube 13 from blocking the tube when sucking a large volume of thrombus 100. Therefore, there is no need to withdraw the suction catheter out of the body, which reduces the surgical risk, and the outer tube 11 sucks the sheared thrombus 100, improving the suction efficiency and reliability. In addition, the outer tube 11 cooperates to capture the broken thrombus, reduces the escape of the broken thrombus, and improves the suction efficiency and reliability. When facing the soft thrombus 100 environment, the inner tube 13 performs a feeding movement, so that the distal end of the inner tube 13 extends out of the shearing piece 2. At this time, the inner tube 13 and the outer tube 11 simultaneously suck the thrombus 100, and the thrombus 100 is discharged from the body through the first suction chamber 1M and the second suction chamber 1N. In addition, since the pressure of the inner tube 13 for aspirating the thrombus 100 is greater than or equal to the pressure of the outer tube 11 for aspirating the thrombus 100, and the space occupied by the supporting middle tube 12 is reduced, the blood loss during aspirating the thrombus 100 is reduced. Facing the complex blood coagulation environment, both hard thrombus 100 clots and soft thrombus 100 clots can be aspirated, which increases the application scope of the thrombus 100 aspiration catheter and reduces the surgical risk of patients.

[0054] The shearing piece 2 includes at least two shearing parts 24. The shearing piece 2 is connected to the middle tube 12. The inner tube 13 can pass through the shearing piece 2 and reciprocate. The shearing parts 24 are elastic. When the inner tube 13 passes through the shearing piece 2, the inner tube 13 pushes against the shearing parts 24 to deform the shearing parts 24, and the shearing parts 24 are located on the outer surface of the inner tube 13. After the inner tube 13 extends out of the shearing piece 2, the thrombus 100 is sucked out. The large volume of the thrombus 100 is located at the end of the inner tube 13. When the inner tube 13 retracts, the shearing parts 24 are reset and located at the end of the inner tube 13. The thrombus 100 moves simultaneously with the inner tube 13. The two adjacent shearing parts 24 are used to shear the thrombus 100 and cut the large volume of the thrombus 100 into pieces. By utilizing the elasticity of the shearing parts 24, the inner tube 13 can pass through when deformed, and can shear the thrombus 100 when reset.

[0055] The distal end of the inner tube 13 extends from the shearing member 2 to aspirate the thrombus 100. However, since a large thrombus 100 is usually formed over a long period of time, contains insoluble fibrin and deposited blood cells, and has a certain elasticity, it is difficult for the suction force to tear it apart. The inner tube 13 is accompanied by a certain frequency of reciprocating motion during aspiration. The reciprocating motion frequency of the inner tube 13 is 1 time / s-10 times / s. For example, it can be 1 time / s, 2 times / s, 3 times / s, 4 times / s, 5 times / s, 6 times / s, 7 times / s, 8 times / s, 9 times / s or 10 times / s, etc., without limitation. After the inner tube 13 extends from the shearing member 2, it is immediately withdrawn to the inside of the shearing member 2. In the process of passing through the shearing member 2, the thrombus 100 is cut off by the closing force of the shearing member 2 when it is closed. Compared with conventional aspiration using only pulling force, the resistance of thrombus 100 to radial shear force is one-fifth of that to axial shear force. Therefore, using aspiration pulling force plus shear force to assist in cutting off the elastic thrombus 100 is more conducive to gradually removing large-volume embolic materials without causing distal blockage of the aspiration catheter.

[0056] The inner tube 13 aspirates the thrombus 100 intermittently or continuously; the outer tube 11 aspirates the thrombus 100 intermittently or continuously. The inner tube 13 and the outer tube 11 can aspirate the thrombus 100 intermittently or continuously at the same time, or one aspirates the thrombus 100 intermittently and the other aspirates the thrombus 100 continuously, which can be set according to actual use conditions without limitation. The intermittent aspiration mode can reduce the amount of blood loss caused by aspiration.

[0057] When the inner tube 13 reciprocates, the outer tube 11 remains stationary, and the suction frequency of the outer tube 11 is the same as the reciprocating frequency of the inner tube 13. When the inner tube 13 retracts through the shearing member 2, the outer tube 11 suctions the thrombus 100. The suction frequency of the outer tube 11 is 1 time / s-10 times / s, and can be 1 time / s, 2 times / s, 3 times / s, 4 times / s, 5 times / s, 6 times / s, 7 times / s, 8 times / s, 9 times / s or 10 times / s, etc., without limitation. The suction frequency of the outer tube 11 is consistent with the movement frequency of the inner tube 13, so that suction is performed only when the head end of the inner tube 13 carries the thrombus 100 and retracts through the shearing piece 2. This is because it is difficult to avoid the generation of broken thrombus particles when the shearing piece 2 cuts off the thrombus 100, and the shearing piece 2 tending to close will cause adverse obstruction to the effective suction area of ​​the inner tube 13. Therefore, the outer tube 11 is required to provide intermittent suction pressure to collect the broken thrombus particles, thereby preventing the broken thrombus particles from escaping and causing distal embolism, thereby enhancing the efficiency of extracting the thrombus 100.

[0058] The inner tube 13 is connected to a feeding mechanism outside the body, such as a cam 5 or a push rod, so as to realize the regular reciprocating motion of the inner tube 13 .

[0059] The distance between the shearing piece 2 and the distal end of the outer tube 11 is 0.5 mm-20 mm, specifically 0.5 mm, 5 mm, 10 mm, 15 mm or 20 mm, etc., to avoid the outer tube 11 being difficult to suck out the broken plugs due to the distance being too far.

[0060] The shearing piece 2 is a first shearing piece, i.e., a leakproof type. The shearing piece 2 is in the shape of a plate. The four sides of the shearing piece 2 are connected to the inner wall of the middle tube 12. The middle positions of the two sides of the shearing piece 2 are respectively provided with a first incision 21 and a second incision 22. The first incision 21 and the second incision 22 are not completely crossed, i.e., partially crossed. The first incision 21 and the second incision 22 allow the inner tube 13 to pass through on both sides of the shearing piece 2 at the intersection, and do not allow the inner tube 13 to pass through at the uncrossed position, i.e., the first incision 21 and the second incision 22 are not cut through, and the depth of the incision is less than the thickness of the shearing piece 2. Exemplarily, there is an intersection between the two, and the intersection is at the center of the shearing piece 2. Shearing portions 24 are respectively formed on both sides of the first incision 21 and the second incision 22. When the inner tube 13 passes through the center of the shearing piece 2, the shearing portion 24 seals the outer surface of the inner tube 13. That is, the first incision 21 forms a first shearing portion 24, and the second incision 22 forms a second shearing portion 24. The first shearing portion 24 is located on one side of the second incision 22, and the second shearing portion 24 is located on one side of the first incision 21. Since the shearing piece 2 has separate incisions on both sides, when the inner tube 13 is inserted into the shearing piece 2, the shearing portions 24 at different phases on both sides can achieve sealing of the outer surface of the inner tube 13. The first shearing piece, i.e., the leak-proof shearing piece 2, can play the role of shearing the thrombus 100 and closing the shearing cavity 1P.

[0061] Exemplarily, the shearing piece 2 is adapted to the shape of the intermediate tube 12, such as a circular plate shape, and the first incision 21 and the second incision 22 can be straight-line, cross-shaped, etc., such as a straight line to form a two-petal shearing portion 24, a cross-shaped to form a four-petal shearing portion 24, or a trident-shaped to form a three-petal shearing portion 24. In other embodiments, the first incision 21 can also be any other shape to form a multi-petal shearing portion 24. The shapes of the first incision 21 and the second incision 22 can be the same or different. Exemplarily, the first incision 21 and the second incision 22 are both straight-line, and neither is cut through, but there is an intersection at the center position and the inner tube 13 is allowed to pass through on both sides of the shearing piece 2. Exemplarily, one of the first incision 21 and the second incision 22 is cross-shaped and the other is straight-line. Similarly, as long as the straight-line and cross-shaped do not completely intersect, but there is an intersection at the center position and the inner tube 13 is allowed to pass through on both sides of the shearing piece 2.

[0062] The number of shearing portions 24 on both sides can be the same or different. Depending on the number of petals, there will be different numbers of cuts on the front and back sides. For example, the middle tube 12 and the shearing piece 2 can be integrally formed or made separately and then fixedly connected by bonding or welding. The first cut 21 and the second cut 22 are both cross-shaped, forming four-petal shearing portions 24 respectively. The center of the cross is located on the center line of the middle tube 12, and the inner tube 13 can pass through the center of the cross.

[0063] When contrast solution is injected into the inner tube 13, the proximal ends of the intermediate tube 12 and the outer tube 11 are closed. That is, when the leak-proof shearing part 24 is used, when the inner tube 13 passes through the shearing piece 2, the shearing piece 2 is completely sealed to prevent the contrast agent from being lost to the intermediate tube 12. At this time, the inner tube 13 can inject contrast solution into the target blood vessel position to deepen the clarity of the thrombus 100, thrombus and other tissues under X-ray. The vacuum source is a vacuum pump. The outer tube 11, the intermediate tube 12 and the inner tube 13 are all connected to the one-way valve through the Luer head 3, and then connected to the vacuum pump outside the body. At this time, the intermediate tube 12 and the outer tube 11 are closed through the distal Luer head, and no suction is performed at this moment, which further prevents the contrast solution from entering the intermediate tube 12 and the outer tube 11 and reduces the amount entering the body, affecting the use effect. Further, the outer tube 11, the intermediate tube 12 and the inner tube 13 are all sealed and connected to the Luer head 3 through a sealing member 4 such as a sealing ring to ensure sealing and prevent leakage.

[0064] During the suction process, the inner tube 13 will inevitably cause a loss of suction pressure due to the influx of a large amount of thrombus 100, even if only a small amount of thrombus 100 adheres to the wall of the second suction chamber 1N, i.e., the inner tube 13. The proximal end of the intermediate tube 12 is connected to a liquid supply device, which is used to supply flushing liquid. The inner tube 13 is withdrawn to the inside of the shearing piece 2, and the flushing liquid is continuously injected into the shearing chamber 1P, and is extracted from the body from the second suction chamber 1N through the shearing chamber 1P. There is a negative pressure in the second suction chamber 1N, and the positive pressure provided by the flushing force of the flushing liquid is superimposed, so that the suction pressure of the entire suction cycle can reach 130Kpa, or even higher. The thrombus 100 in the second suction chamber 1N and the thrombus 100 adhered to the tube wall can be effectively flushed and discharged, which significantly increases the efficiency of decomposing and extracting the thrombus 100 out of the body.

[0065] The pressure of the inner tube 13 is greater than the pressure of the outer tube 11 or the pressure of the inner tube 13 is equal to the pressure of the outer tube 11; whether the shear chamber 1P is supplied with flushing fluid; whether the inner tube 13 is injected with contrast fluid; the inner tube 13 intermittently aspirates the thrombus 100 or continuously aspirates the thrombus 100; the outer tube 11 intermittently aspirates the thrombus 100 or continuously aspirates the thrombus 100; whether the inner tube 13 performs a reciprocating motion extending out of the shear member 2. The above multiple options can be arbitrarily combined and used to form different working modes to adapt to different working conditions.

[0066] In one embodiment, when the shearing member 2 is the first shearing member, at t a -t b During the time period, the pressure of the second suction chamber 1N is greater than the pressure of the first suction chamber 1M, and at t a - During the T time period, the liquid supply equipment supplies flushing liquid. b During the time period, the inner tube 13 reciprocates to cause the shearing member 2 to shear the thrombus 100, wherein t a <T<t b .like Fig.12 As shown, it is a schematic diagram of the suction working condition when a large embolic object blocks the tip of the outer tube 11. The horizontal axis is time, and the vertical axes of the four coordinates are the fluid pressure in the first suction chamber 1M, the shear chamber 1P and the second suction chamber 1N, and the extension movement of the inner tube 13. In the first three coordinates, the positive direction of the vertical axis represents suction, and the reverse direction represents the injection of fluid. In the fourth coordinate, the positive direction of the vertical axis represents the extension movement of the inner tube 13. Specifically, the suction process and the flushing process are used in conjunction. t a is 0, T is t1, t bis t2. During 0-t2, the outer tube 11 and the inner tube 13 always maintain a certain pressure difference in suction, that is, the pressure of the inner tube 13 is greater than the pressure of the outer tube 11. During 0-t1, the intermediate tube 12 continuously injects flushing fluid from the proximal end to the distal end. During this process, the fluid is drawn out of the body from the first suction chamber 1M and the second suction chamber 1N through the shear chamber 1P, carrying the cut thrombus 100. During t1-t2, the fluid injection stops. At this time, the inner tube 13 extends out of the shear member 2, captures part of the thrombus 100 and then withdraws to the inside of the shear member 2. The shear member 2 is closed. In this process, the shear force of the shear member 2 cuts off the thrombus 100. At this time, the inner tube 13 is extended out of the shear member 2 for suction to capture the thrombus 100, and the outer tube 11 suctions the broken thrombus. Thereafter, the above suction-flushing-shearing cycle is repeated until the embolus is cleared.

[0067] In one embodiment, Fig.13 As shown, a schematic diagram of the suction working condition of a soft thrombus 100 is shown, where the horizontal axis is time, and the vertical axes of the four coordinates are the fluid pressure in the first suction chamber 1M, the shear chamber 1P, and the second suction chamber 1N, and the extension movement of the inner tube 13. In the first three coordinates, the positive direction of the vertical axis represents suction, and the reverse direction represents the injection of fluid. In the fourth coordinate, the positive direction of the vertical axis represents the extension movement of the inner tube 13. Specifically, during the period 0-t1, the outer tube 11 of the suction catheter and the inner tube 13 of the suction catheter always maintain a certain pressure difference for suction, that is, the pressure of the inner tube 13 is greater than the pressure of the outer tube 11, and the inner tube 13 of the suction catheter extends out of the shearing part 2, without the action of withdrawing to the inside of the shearing part 24, and there is no need for the intermediate tube 12 to inject flushing fluid to the distal end.

[0068] like Fig.14 and Fig.15 As shown, the outer tube 11, the middle tube 12 and the inner tube 13 all include a lubricating layer 111, a reinforcing layer 112 and a polymer layer 113 arranged from the inside to the outside. Taking the outer tube 11 as an example for exemplary description, the outer tube 11 includes a lubricating layer 111 arranged on the inner layer, one or two reinforcing layers 112 and a polymer layer 113 arranged on the outer layer from the inside to the outside. The lubricating layer 111 can be made of materials such as PTFE, FEP, TPE, TPU, PEBAX, PEEK, etc., which not only takes into account the support of the outer tube 11 but also reduces the wall thickness of the outer tube 11, so that the inner surface of the outer tube 11 has a smaller friction. The reinforcing layer 112 includes a spring layer 1121 and a braided layer 1122, which can be one of them or a combination of two of them. Preferably, a structure combining the spring layer 1121 and the braided layer 1122 is adopted, and the material can be one or more of NiTi, stainless steel, and high-strength polymer wire; the polymer layer 113 can be made of TPU, TPE, polyamide, polyimide, elastic polyurethane, nylon, polyethylene terephthalate (PET), polytetrafluoroethylene, perfluoroethylene propylene copolymer and / or polyetheretherketone.

[0069] The structure of the middle tube 12 and the inner tube 13 refers to the structure of the outer tube 11. In particular, in order to ensure the overall support and flexibility of the suction catheter, that is, to ensure that the pushing force applied to the handle can be transmitted to the head end of the suction catheter, and the suction catheter can smoothly pass through the tortuous blood vessels, in this embodiment, the outer tube 11 adopts a two-layer reinforcement layer 112 structure of a braided layer 1122 plus a braided layer 1122 to maintain a certain support performance of the outer tube 11 during the suction process. The middle tube 12 is only subjected to the injection pressure and does not need to resist the negative pressure generated by the suction. Therefore, only the braided layer 1122 can be used or the thickness of the polymer layer 113 can be reduced to reduce the overall wall thickness of the suction catheter. The inner tube 13 needs to be supported inside and resist the negative pressure of suction, so a two-layer reinforcement layer 112 structure of a braided layer 1122 plus a braided layer 1122 is used.

[0070] The distal end of the outer tube 11, i.e., the distal opening, is an oblique opening 114 or a straight opening 115, and / or the distal end of the inner tube 13, i.e., the distal opening, is an oblique opening 114 or a straight opening 115. The outer tube 11 and the inner tube 13 can both be oblique openings 114 or straight openings 115, or one can be a straight opening 115 and the other oblique opening 114. Compared with the straight opening 115, the oblique opening 114 increases the contact area with the thrombus 100, i.e., the suction area, and thus increases the suction volume, because under the same suction pressure, the suction flow rate is proportional to the suction area.

[0071] The inner diameter of the outer tube 11 is D1, the wall thickness is W1, and the outer diameter is D2. The inner diameter of the intermediate tube 12 is D3, the wall thickness is W2, and the outer diameter is D4. The inner diameter of the inner tube 13 is D5, the wall thickness is W3, and the outer diameter is D6. The inner diameter D1 of the outer tube 11 is generally related to the inner diameter of the suction segment blood vessel. The inner diameter D1 of the outer tube 11 is at least 0.1 mm larger than the outer diameter D4 of the intermediate tube 12. The length can be selected from 0.1, 0.2, 0.3, 0.4, 0.5 mm, etc. The larger the difference between the two, the larger the volume of the first suction cavity 1M, but the larger the outer diameter of the suction catheter as a whole. The inner diameter D3 of the intermediate tube 12 is at least 0.1 mm larger than the outer diameter D5 of the inner tube 13. The length can be selected from 0.1, 0.2, 0.3, 0.4, 0.5 mm, etc. The larger the difference between the two, the larger the volume of the shear cavity 1P, but the larger the outer diameter of the suction catheter as a whole. The wall thickness W2 of the intermediate tube 12 is not greater than 0.5 mm, preferably 0.1 mm or even less, to reduce the overall outer diameter of the suction catheter. The ratio of the inner diameter D3 of the intermediate tube 12 to the inner diameter D1 of the outer tube 11 is not less than 50%, preferably greater than or equal to 75%. Exemplarily, the outer diameter D2 of the outer tube 11 is 2.7 mm, and the inner diameter D1 is 2.45 mm, the outer diameter D4 of the intermediate tube 12 is 2.35 mm, and the inner diameter D3 is 2.2 mm, and the outer diameter D6 of the inner tube 13 is 2.1 mm, and the inner diameter D5 is 1.85 mm.

[0072] Embodiment 2

[0073] This embodiment provides a suction catheter, which has a structure that is substantially the same as that of the first embodiment, and the similarities are not repeated here. Figure 16-Figure 19 As shown, Fig.19 It is a schematic diagram of the state of thrombus aspiration, and the flow direction of the thrombolytic drug is F. The shearing piece 2 is a second shearing piece, i.e., a non-leak-proof type. The shearing piece 2 is in the shape of a plate. The shearing piece 2 is connected to the inner wall of the intermediate tube 12 on all sides. The shearing piece 2 is provided with a third incision 23 to allow the inner tube 13 to pass through on both sides of the shearing piece 2, i.e., the incision depth is the thickness of the shearing piece 2. Shearing portions 24 are formed on both sides of the third incision 23. When the inner tube 13 passes through the third incision 23, a leakage port is formed between adjacent shearing portions 24 and the outer surface of the inner tube 13. The shearing piece 2 may include two-petal, three-petal or multi-petal shearing portions 24. The shearing piece 2 is made of silicone material. According to the number of petals, different numbers and shapes of incisions are set. In this embodiment, the third incision 23 is cross-shaped to form a four-petal shearing portion 24. Since the third cut 23 cuts through, when the inner tube 13 is inserted into the shearing piece 2, the third cut 23 is deformed, that is, a leakage hole is formed between the adjacent shearing portion 24 and the outer surface of the inner tube 13, and liquid will leak from the leakage hole. At this time, the outer surface of the inner tube 13 is not completely sealed.

[0074] When contrast fluid is injected into the middle tube 12, the inner tube 13 and the proximal end of the outer tube 11 are closed. Since the shearing piece 2 is not completely sealed, the middle tube 12 can inject contrast fluid into the target blood vessel at low pressure at this time, deepening the clarity of the thrombus 100, thrombus and other tissues under X-ray. At this time, the inner tube 13 and the outer tube 11 are closed by the distal Luer head, and no suction is done at this moment, so as to avoid the contrast fluid being sucked out of the body through the inner tube 13 and the outer tube 11 and affecting the use effect.

[0075] The proximal end of the intermediate tube 12 is connected with a liquid supply device, which is used to supply thrombolytic drugs. Since the shearing piece 2 is not completely sealed, a fluid containing thrombolytic drugs is injected to the distal end through the intermediate tube 12 to erode and soften the embolus. When the thrombolytic drugs are in full contact with the thrombus 100, the waste liquid is sucked out of the body through the first suction chamber 1M and the second suction chamber 1N to prevent the problem of suction catheter blockage. The thrombolytic drugs are one or more of urokinase, lumbrokinase, streptokinase, nattokinase, and tissue plasminogen activator.

[0076] The inner tube 13 and the outer tube 11 both intermittently aspirate the thrombus 100, and the aspiration frequency is 1 time / s-10 times / s, and specifically can be 1 time / s, 2 times / s, 3 times / s, 4 times / s, 5 times / s, 6 times / s, 7 times / s, 8 times / s, 9 times / s or 10 times / s, etc., without limitation. When the thrombolytic drug is in full contact with the thrombus 100, the injection of the thrombolytic drug can be stopped, thereby controlling the concentration of the thrombolytic drug at the distal end.

[0077] In one embodiment, when the shearing member 2 is the second shearing member, at t a-t b During the time period, the pressure of the second suction chamber 1N is greater than the pressure of the first suction chamber 1M, and the liquid supply device supplies thrombolytic drugs. b During the time period, the inner tube 13 reciprocates to cause the shearing member 2 to shear the thrombus 100, wherein t a <T<t b .like Fig. 20 As shown, it is a schematic diagram of the working condition of thrombolytic drug eroding thrombus 100, the horizontal axis is time, and the vertical axes of the four coordinates are the fluid pressure in the first suction chamber 1M, the shear chamber 1P and the second suction chamber 1N, and the extension movement of the inner tube 13. In the first three figures, the positive direction of the vertical axis represents suction, and the reverse direction represents injection of fluid. In the fourth coordinate, the positive direction of the vertical axis represents the extension movement of the inner tube 13. a is 0, T is t1, t b Specifically, during the period of 0-t2, the outer tube 11 and the inner tube 13 always maintain a certain pressure difference for suction, and the intermediate tube 12 continuously injects the fluid containing the thrombolytic drug from the proximal end to the distal end, the fluid flows to the embolism through the shearing member 2, and softens by contacting with the embolism such as thrombus 100, and the inner tube 13 and the outer tube 11 suck the mixed fluid of the drug fluid and the softened thrombus 100. During the period of t1-t2, the inner tube 13 extends out of the shearing member 2, and the inner tube 13 and the outer tube 11 suck the mixed fluid of the drug fluid and the softened thrombus 100, and the inner tube 13 captures the softened thrombus 100 and then withdraws to the inside of the shearing member 2, and the mixed fluid of the thrombus 100 further separated by the shearing member 2 is sucked out.

[0078] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A suction catheter, characterized in that: The invention comprises a catheter assembly (1) and a shearing piece (2), wherein the catheter assembly (1) comprises an outer tube (11), an intermediate tube (12) and an inner tube (13), wherein the outer tube (11) is sleeved on the intermediate tube (12) to form a first suction chamber (1M) therebetween, and the inner tube (13) has a second suction chamber (1N), and the intermediate tube (12) is sleeved on the inner tube (13) to form a shearing chamber (1P) therebetween, and the proximal ends of the outer tube (11) and the inner tube (13) are both connected to a vacuum source so that the first suction chamber (1M) is formed in the inner tube (13). The first chamber (1M) and the second suction chamber (1N) respectively form negative pressure for aspirating the thrombus (100), and the pressure of the second suction chamber (1N) is not less than the pressure of the first suction chamber (1M), so that the outer tube (11) and the inner tube (13) form a step-by-step aspiration mode; the shearing member (2) is arranged at the distal end of the catheter assembly (1); after the second suction chamber (1N) aspirates the thrombus (100), the shearing member (2) can shear the thrombus (100) located outside the second suction chamber (1N); The shearing piece (2) comprises at least two shearing portions (24). The shearing piece (2) is connected to the intermediate tube (12). The inner tube (13) can pass through the shearing piece (2) and reciprocate. The shearing portions (24) are elastic. When the inner tube (13) passes through the shearing piece (2), the inner tube (13) pushes against the shearing portions (24) to deform the shearing portions (24). The shearing portions (24) are located on the outer surface of the inner tube (13). When the inner tube (13) retracts, the shearing portions (24) are reset to the end of the inner tube (13). Two adjacent shearing portions (24) are used to shear the thrombus (100).

2. The suction catheter according to claim 1, characterized in that The shearing piece (2) is a first shearing piece, and the shearing piece (2) is in the shape of a plate. The four sides of the shearing piece (2) are connected to the inner wall of the intermediate tube (12). The two sides of the shearing piece (2) are respectively provided with a first cutout (21) and a second cutout (22). The first cutout (21) and the second cutout (22) partially intersect. The first cutout (21) and the second cutout (22) allow the inner tube (13) to pass through the two sides of the shearing piece (2) at the intersection. The two sides of the first cutout (21) and the two sides of the second cutout (22) respectively form the shearing portions (24). When the inner tube (13) passes through the center position of the shearing piece (2), the shearing portions (24) seal the outer surface of the inner tube (13); or, The shearing piece (2) is a second shearing piece. The shearing piece (2) is in the shape of a plate. The four sides of the shearing piece (2) are connected to the inner wall of the intermediate tube (12). The shearing piece (2) is provided with a third cutout (23) so that the inner tube (13) can pass through the two sides of the shearing piece (2). The shearing portions (24) are formed on both sides of the third cutout (23). When the inner tube (13) passes through the third cutout (23), a leakage port is formed between the adjacent shearing portions (24) and the outer surface of the inner tube (13).

3. The suction catheter according to claim 2, characterized in that The proximal end of the intermediate tube (12) is connected to a liquid supply device. When the shearing member (2) is a first shearing member, the liquid supply device is used to supply flushing liquid; When the shearing piece (2) is the second shearing piece, the liquid supply device is used to supply thrombolytic drugs.

4. The suction catheter according to claim 3, characterized in that When the shearing member (2) is the first shearing member, at t a -t b During the time period, the pressure of the second suction chamber (1N) is greater than the pressure of the first suction chamber (1M), and at t a -T period, the liquid supply device supplies flushing liquid, at Tt b During the time period, the inner tube (13) moves back and forth, causing the shearing member (2) to shear the thrombus (100), wherein t a <T<t b ; When the shearing member (2) is the second shearing member, at t a -t b During the time period, the pressure of the second suction chamber (1N) is greater than the pressure of the first suction chamber (1M), and the liquid supply device supplies thrombolytic drugs. b During the time period, the inner tube (13) moves back and forth, causing the shearing member (2) to shear the thrombus (100), wherein t a <T<t b .

5. The suction catheter according to claim 2, characterized in that: When the shearing piece (2) is a first shearing piece, when contrast solution is injected into the inner tube (13), the proximal ends of the intermediate tube (12) and the outer tube (11) are closed; When the shearing piece (2) is the second shearing piece, when contrast fluid is injected into the intermediate tube (12), the proximal ends of the inner tube (13) and the outer tube (11) are closed.

6. The suction catheter according to claim 1, characterized in that The inner tube (13) intermittently aspirates the thrombus (100) or continuously aspirates the thrombus (100); the outer tube (11) intermittently aspirates the thrombus (100) or continuously aspirates the thrombus (100).

7. The suction catheter according to claim 1, characterized in that: The suction frequency of the outer tube (11) is the same as the reciprocating frequency of the inner tube (13), and when the inner tube (13) is withdrawn through the shearing member (2), the outer tube (11) suctions the thrombus (100).

8. The suction catheter according to claim 1, characterized in that The distal end of the outer tube (11) is an oblique opening (114) or a straight opening (115), and / or the distal end of the inner tube (13) is an oblique opening (114) or a straight opening (115).

9. The suction catheter according to claim 1, characterized in that: The outer tube (11), the middle tube (12) and the inner tube (13) all include a lubricating layer (111), a reinforcing layer (112) and a polymer layer (113) arranged from the inside to the outside.

10. The suction catheter according to any one of claims 1 to 9, characterized in that: The inner diameter of the outer tube (11) is at least 0.1 mm larger than the outer diameter of the intermediate tube (12), and / or the inner diameter of the intermediate tube (12) is at least 0.1 mm larger than the outer diameter of the inner tube (13), and / or the wall thickness of the intermediate tube (12) is not greater than 0.5 mm, and / or the ratio of the inner diameter of the intermediate tube (12) to the inner diameter of the outer tube (11) is not less than 50%.

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