Mechanical thrombus removal device and method

Abstract

The present invention discloses a mechanical thrombus removal device and method, including a collection tank, a thrombus removal catheter, a thrombus cutting assembly and a guide wire. The interior of the collection tank is in a negative pressure state and is connected to the thrombus removal catheter, that is, the interior of the thrombus removal catheter is in a negative pressure state; the thrombus cutting assembly includes an inner blade, an outer blade, a flexible transmission shaft and a power assembly that drives the flexible transmission shaft to rotate, the outer blade is slidably installed on the head of the thrombus removal catheter, and the flexible transmission shaft drives the inner blade to rotate; the power assembly is provided with a pusher that can drive the inner blade and the outer blade to extend from the head of the thrombus removal catheter; the thrombus removal catheter is provided with a first cavity in the middle, and the outer wall is provided with a second cavity for accommodating the guide wire. The present invention adopts the cutting concept of negative pressure suction and mechanical cutting, which can improve the efficiency of thrombus removal, perform in situ excision of thrombi, and avoid distal embolism caused by thrombus fragments that fall off during the process of dragging the thrombus during negative pressure suction alone.

Description

Technical Field

[0001] The present invention relates to the field of medical devices, and in particular to a mechanical thrombus removal device and method. Background Art

[0002] Thrombosis is caused by coagulation in the blood circulation system of the human body, or by the analysis and coagulation of certain formed substances in the blood into solid masses. Unlike blood clots formed under natural conditions, thrombi are formed when blood is flowing, and will be carried downstream by the blood flow to block blood vessels in the brain, heart, lungs or limbs. These blockages are called emboli. After thrombus formation, it will block blood vessels, causing a decrease in blood flow or even blocking blood flow, resulting in increased pressure in blood vessels upstream of the blockage, causing stroke, heart attack, pulmonary embolism or deep vein thrombosis and other diseases. It will also cause insufficient blood supply downstream of the blockage, resulting in ischemia, leading to tissue and cell death, and even threatening the patient's life in severe cases.

[0003] At present, medical treatment and negative pressure aspiration are commonly used in clinical practice. Medical treatment usually uses anticoagulation, thrombolysis and other methods, but these methods have a long treatment cycle and there are problems such as limited treatment time window, and the efficacy is average. Single aspiration treatment has a certain effect on small fresh thrombi, but it is difficult to aspirate and remove large thrombi. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a mechanical thrombus removal device and method, which can effectively remove emboli in blood vessels and restore blood flow.

[0005] To this end, the technical solution of the present invention is: a mechanical thrombus removal device, comprising a collection tank, a thrombus removal catheter, a thrombus cutting assembly and a guide wire, wherein the interior of the collection tank is in a negative pressure state and is connected to the thrombus removal catheter, that is, the interior of the thrombus removal catheter is in a negative pressure state;

[0006] The thrombus cutting assembly comprises an inner blade, an outer blade, a flexible transmission shaft and a power assembly for driving the flexible transmission shaft to rotate. The outer blade is slidably mounted on the head of the thrombus removal catheter, and the flexible transmission shaft drives the inner blade to rotate inside the outer blade.

[0007] The power assembly is provided with a pusher, which can drive the inner blade and the outer blade to extend out from the head of the thrombus removal catheter;

[0008] The thrombus removal catheter has a first cavity in the middle for accommodating a flexible transmission shaft, and a second cavity on the outer wall for accommodating a guide wire.

[0009] On the basis of the above scheme and as a preferred scheme of the above scheme: the power assembly includes a housing, a motor bracket and a motor, the motor is installed on the motor bracket and connected to the flexible transmission shaft through a coupling; the motor bracket is slidably installed in the housing, and the pushing member is installed at the upper end of the motor bracket to push the motor bracket to move.

[0010] On the basis of the above scheme and as a preferred scheme of the above scheme: the outer blade is cylindrical, and a first cutting edge inclined inward is provided at the front end; the inner blade is a sheet-like structure, and is restricted in the outer blade by a retaining ring; a second cutting edge is provided on each side of the front end of the inner blade, and the rear end of the inner blade is fixedly connected to the flexible transmission shaft; during the rotation of the inner blade, the second cutting edge and the first cutting edge form a shear structure.

[0011] On the basis of the above scheme and as a preferred scheme of the above scheme: a developing ring is fixed inside the head of the thrombus removal catheter, a boss is provided on the inner wall of the developing ring, a guide groove is provided on the outer wall of the outer blade, and the boss and the guide groove are slidably matched.

[0012] On the basis of the above scheme and as a preferred scheme of the above scheme: a metal braided structure is provided in the tube wall of the thrombus removal catheter, which is formed by a plurality of metal wires interlaced and woven together.

[0013] On the basis of the above scheme and as a preferred scheme of the above scheme: the length of the thrombus removal catheter is 1.5m-2.5m, the inner diameter of the first cavity is 1.5mm-2.8mm, and the inner diameter of the second cavity is 0.35-0.5mm.

[0014] On the basis of the above scheme and as a preferred scheme of the above scheme: the flexible transmission shaft is formed by winding a plurality of metal filaments, and the interior of the flexible transmission shaft is hollow or a metal wire can be inserted.

[0015] On the basis of the above scheme and as a preferred scheme of the above scheme: the tail of the thrombus removal catheter is connected to the power assembly and the collection tank through a three-way seal, the first port of the seal is connected to the collection tank through a suction catheter, the second port is connected to the tail of the thrombus removal catheter, and the third port is connected to the power assembly, and the caliber of the third port is consistent with the outer diameter of the flexible transmission shaft.

[0016] On the basis of the above scheme and as a preferred scheme of the above scheme: the first interface of the collection tank is connected to a negative pressure generator through a pipeline, and the second interface is connected to a sealing member through a suction catheter.

[0017] Another technical solution of the present invention is: a mechanical thrombus removal method, comprising the following steps:

[0018] 1) Insert the thrombus removal catheter into the blood vessel and guide it to the location of the thrombus under the guidance of the guide wire;

[0019] 2) Start the negative pressure generator, the collection tank and thrombus removal catheter are both in a negative pressure state, and the thrombus is adsorbed to the tube mouth;

[0020] 3) Start the motor, and the flexible transmission shaft drives the inner blade to rotate, which cooperates with the outer blade to form a shearing structure to cut the large thrombus into thrombus fragments;

[0021] 4) During the thrombus chopping process, the inner blade and the outer blade are pushed out of the thrombus removal catheter by the pusher, and the whole thrombus sucked into the inner cavity is chopped into smaller fragments;

[0022] 5) The negative pressure in the thrombus removal catheter is used to draw the thrombus debris into the collection tank to complete the removal of the thrombus.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The combined cutting concept of negative pressure aspiration and mechanical cutting can not only improve the efficiency of thrombus removal, but also remove the thrombus in situ, avoiding distal embolism caused by thrombus fragments that fall off during the dragging of the thrombus during negative pressure aspiration alone.

[0025] 2. A flexible transmission shaft is used to drive the inner blade to rotate at high speed, so that the cutting edges on the inner and outer blades cooperate with each other to form a special dynamic shearing structure, which can fully shear the thrombus into debris, especially for relatively hard old thrombus in clinical practice, with high thrombus breaking efficiency.

[0026] 3. During the thrombus removal process, the thrombus cutting component can be pushed forward slightly to break the thrombus more thoroughly. The external cutting component does not directly contact the blood vessel. The rest of the time, the thrombus cutting component is retracted into the catheter, which can avoid damage to the inner wall and valve of the blood vessel during the advancement and removal process.

[0027] 4. The thrombus removal catheter is a double-lumen braided tube. The thrombus cutting component and the guide wire are located in two independent cavities without interfering with each other, which makes it convenient for the thrombus cutting component to shear the thrombus and improve the removal efficiency. There is a metal braided layer inside the tube wall to improve the strength of the catheter and ensure that it will not be deformed due to negative pressure suction when the wall thickness is thin.

[0028] 5. A developing ring is provided at the head of the thrombus removal catheter, and the position of the catheter can be grasped by spraying contrast agent during the operation; at the same time, a boss is provided on the developing ring to provide guidance for the movement of the outer blade. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of the present invention;

[0030] Figure 2 It is an exploded view of the parts of the power assembly of the present invention;

[0031] Figure 3 An exploded view of the parts of the thrombus cutting assembly of the present invention;

[0032] Figure 4 It is a schematic structural diagram of the sealing member of the present invention;

[0033] Figure 5 It is a structural cross-sectional view of the sealing member of the present invention;

[0034] Figure 6 It is a structural cross-sectional view of the thrombus removal catheter of the present invention;

[0035] Figure 7 It is a schematic diagram of the metal braided layer of the thrombus removal catheter of the present invention;

[0036] Figure 8 This is a structural cross-sectional view of the flexible transmission shaft (with stainless steel wire) of the present invention;

[0037] Fig. 9 It is a structural schematic diagram of the flexible transmission shaft of the present invention;

[0038] Fig.10 It is an exploded view of the parts of the developing ring, inner blade, outer blade and retaining ring of the present invention;

[0039] Fig.11 It is a schematic diagram of the assembly of the developing ring, the inner blade, the outer blade and the retaining ring of the present invention;

[0040] Fig.12 This is a schematic diagram of thrombus removal according to the present invention.

[0041] Marked in the figure are: negative pressure generator 1, first suction catheter 2, second suction catheter 3, collecting tank 4, power assembly 5, seal 6, first port 61, second port 62, third port 63, thrombus removal catheter 7, first cavity 71, second cavity 72, metal braided structure 73, accommodating groove 74, thrombus cutting assembly 8, guide wire 9, pusher 10, motor 11, coupling 12, motor bracket 13, housing 14, long slot hole 141, flexible transmission shaft 15, retaining ring 16, first blocking surface 161, second blocking surface 162, inner blade 17, second cutting edge 171, outer blade 18, guide groove 181, first cutting edge 182, stainless steel wire 19, developing ring 20, boss 201, thrombus 21, thrombus debris 22. DETAILED DESCRIPTION

[0042] In the description of the present invention, it should be noted that directional words, such as the terms "center", "lateral (X)", "longitudinal (Y)", "vertical (Z)", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions and positional relationships are based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of narrating the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and cannot be understood as limiting the specific scope of protection of the present invention.

[0043] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features. Therefore, the definition of "first" and "second" features can explicitly or implicitly include one or more of the features. In the description of the present invention, "several" and "a number" mean two or more, unless otherwise clearly and specifically defined.

[0044] See the attached drawings. The mechanical thrombus removal device described in this embodiment is used to remove thrombi in human blood vessels. The thrombus removal device enters a designated position of a blood vessel under the guidance of a guide wire to remove thrombi. The types of thrombi include but are not limited to deep vein thrombosis, pulmonary embolism, and the like.

[0045] like Figure 1 The thrombus removal device includes a negative pressure generator 1, a collection tank 4, a thrombus removal catheter 7, a thrombus cutting assembly 8 and a guide wire 9. The negative pressure generator 1 has a built-in negative pressure pump that can generate a stable negative pressure. The two ends of the first suction catheter 2 are respectively connected to the negative pressure generator and the collection tank 4, and the negative pressure generated by the negative pressure pump is transmitted to the collection tank 4, so that the collection tank 4 is in a negative pressure state. At the same time, the negative pressure in the collection tank 4 continues to be transmitted to the thrombus removal catheter 7 through the second suction catheter 3 and the seal 6.

[0046] For the convenience of description, the end of the thrombus removal catheter 7 extending into the blood vessel is defined as the distal end (head), and the end connected to the seal 6 is defined as the proximal end (tail). The negative pressure is transmitted and finally reaches the distal end of the thrombus removal catheter 7, sucking the thrombus into the distal end tube mouth.

[0047] The proximal end of the thrombus removal catheter 7 is connected to the power assembly 5 and the collection tank 4 through a seal. The seal 6 is a three-way connector. The first port 61 of the seal 6 is connected to the collection tank through the second suction catheter 3, the second port 62 is connected to the proximal end of the thrombus removal catheter 7, and the third port 63 is connected to the power assembly 5. The inner cavity diameter of the third port 63 is consistent with the outer diameter of the flexible transmission shaft 15, and forms a sealing structure with the flexible transmission shaft 15 to reduce the airflow passing through the channel, thereby ensuring the overall airtightness of the device and ensuring that most of the negative pressure from the suction catheter 3 can be transmitted to the second port 62 through the first port 61.

[0048] like Figure 6 As shown, the thrombus removal catheter 7 is an integral double-lumen catheter. The larger first cavity 71 is used to accommodate the thrombus cutting assembly 8 and to aspirate thrombus debris. The smaller second cavity 72 is used to pass the guide wire 9 to facilitate guiding the thrombus removal catheter 7 in the blood vessel to reach the lesion. The proximal end of the thrombus removal catheter 7 is a trumpet-shaped opening to facilitate connection with the sealing member 6.

[0049] The length L of the thrombus removal catheter 7 is 1.5m to 2.5m, the larger inner diameter d1 of the first cavity 71 is 1.5mm to 2.8mm, and the smaller inner diameter d2 of the second cavity 72 is 0.35-0.5mm. Preferably, the outer diameter of the thrombus removal catheter 7 is 1.5m, the inner diameter of the first cavity 71 is 2.4mm, and the inner diameter of the second cavity 72 is 0.4mm.

[0050] like Figure 7 As shown, the difference between the thrombus removal catheter 7 and the ordinary catheter is that there is a special metal braided structure 73 in the tube wall, which can increase the strength of the catheter when the wall thickness is thin, and ensure that the thrombus removal catheter 7 is not deformed by negative pressure suction. At the same time, this structure can also ensure that the thrombus removal catheter 7 has a certain flexibility, conforms to the blood vessel, and helps to reach the location of the thrombus. As an embodiment, the metal braided structure 73 can be made of 12 strands of metal wires in the order of 6 left-handed and 6 right-handed, which are intertwined and woven with each other. The metal wire material can preferably be 316LVM stainless steel, and the cross-sectional diameter can preferably be 0.07mm. The number of metal wires, cross-sectional diameter, weaving method and material can be appropriately changed according to actual use requirements.

[0051] There is a receiving groove 74 at the mouth of the larger first cavity 71, which can accommodate a special developing ring 20. During the operation, the position of the catheter can be controlled by spraying contrast agent. The inner wall of the developing ring 20 is provided with an axially distributed boss 201, which is used to guide the movement of the outer blade 18.

[0052] like Figure 3As shown, the thrombus cutting assembly 8 includes a flexible transmission shaft 15, a retaining ring 16, an inner blade 17, an outer blade 18 and a power assembly 5 for driving the flexible transmission shaft 15 to rotate; the outer blade 18 is cylindrical, and an axially distributed guide groove 181 is provided on the outer wall of the outer blade 18, and the guide groove 181 is slidably matched with the boss 201 of the developing ring 20.

[0053] like Fig.10 As shown, the outer blade 18 is provided with an inwardly inclined first cutting edge 182 at the port facing the distal end. To ensure the cutting performance of thrombus, the front angle of the first cutting edge 182 is as small as possible to ensure the sharpness of the tool. The front angle can preferably be 30°.

[0054] The inner blade 17 is a sheet-like structure, and the two side surfaces of the inner blade 17 are curved surfaces, and the curvature radius thereof is the same as the curvature of the inner surface of the outer blade 18, which can play a guiding role when the inner blade 17 rotates at a high speed. A second cutting edge 171 is provided on both sides of the front end of the inner blade 17, and the second cutting edges 171 on both sides must be arranged symmetrically to avoid vibration caused by dynamic imbalance when it rotates at a high speed, which affects safety. The rear end of the inner blade 17 is fixedly connected to the flexible transmission shaft 15, which can be welded or connected in other ways.

[0055] One end of the flexible transmission shaft 15 is connected to the motor output shaft through the coupling 12, and the other end is connected to the inner blade 17, so as to transmit the rotation speed and torque generated by the motor 11 to the inner blade 17, and drive the inner blade 17 to rotate at a high speed. During the rotation of the inner blade 17, the second cutting edge 171 of the inner blade 17 and the first cutting edge 182 of the outer blade 18 are kept in contact, forming a shearing structure similar to scissors to cut off the thrombus. The second cutting edge 171 of the inner blade 17 is driven by the power source to rotate at a speed of 5000-10000rpm, and the inner blade 17 can complete two shears for each rotation.

[0056] The retaining ring 16 is a convex structure, and the first blocking surface 161 at the front end fits with the rear end surface of the inner blade 17, and the second blocking surface 162 at the rear end of the retaining ring fits with the rear end surface of the outer blade 18 and is fixedly connected to prevent the inner blade 17 from moving backward, ensuring the accurate fit of the cutting edges of the inner and outer blades and improving the cutting efficiency.

[0057] like Fig. 9 As shown, the flexible transmission shaft 15 must have strong flexibility to conform to the curved blood vessels of the human body, and also have a certain strength to ensure that the torque of the power source is transmitted to the inner blade 17. As an embodiment, the flexible transmission shaft 15 can be wound by three stainless steel filaments, and the material can be preferably 304V alloy steel wire, and the diameter of the filament can be preferably 0.5mm. The three strands of stainless steel wire are wound into a vacuum state according to a right-handed structure using a winding machine.

[0058] There is a suitable gap between the flexible transmission shaft 15 and the inner cavity of the thrombus removal catheter 7 to ensure that the broken thrombus fragments can be sucked through smoothly by negative pressure. As an embodiment, the gap between the flexible transmission shaft 15 and the inner cavity of the thrombus removal catheter 7 is 1 to 1.5 mm. The flexible transmission shaft 15 can also pass through a stainless steel wire 19 to increase its strength and ensure that it is not easily deformed when transmitting torque (such as Figure 8 shown).

[0059] The power assembly 5 includes a housing 14, a motor bracket 13 and a motor 11. The motor 11 is mounted on the motor bracket 13 and connected to the flexible transmission shaft 15 through a coupling 12. A slide rail is provided on the inner bottom surface of the housing 14, and the motor bracket 13 is slidably mounted in the housing 14. A long slot hole 141 is provided on the upper end surface of the housing 14. The pusher 10 passes through the long slot hole 141 and is fixedly connected to the upper end of the motor bracket 13. The thrombus cutting assembly 8 can be driven to move by the pusher 10. The total pushing stroke of the thrombus cutting assembly 8 pushed forward and backward by the pusher 10 is 3 mm.

[0060] The thrombus cutting assembly 8 can be pushed forward under the action of the pusher 10 on the power assembly 5, so that the inner blade and the outer blade extend out 1mm from the distal end of the thrombus removal catheter 7, and the whole thrombus sucked into the distal inner cavity of the thrombus removal catheter 7 is cut and broken into smaller fragments, and then the thrombus fragments are sucked into the collection tank 4 by the negative pressure in the thrombus removal catheter 7 to complete the removal of the thrombus. When not working, the thrombus cutting assembly 8 is located in the thrombus removal catheter 7 to ensure safety; when working, it is pushed forward by the pusher 10, extending 1mm from the thrombus removal catheter 7, cutting the thrombus to ensure effectiveness.

[0061] When using:

[0062] 1) Insert the thrombus removal catheter 7 into the blood vessel and, under the guidance of the guide wire 9, reach the lesion site where the thrombus 21 is located;

[0063] 2) Start the negative pressure generator 1, the negative pressure pump generates a stable negative pressure, the negative pressure is transmitted to the collection tank 4 through the first suction catheter 2, and the collection tank 4 transmits the negative pressure to the thrombus removal catheter 7 through the second suction catheter 3;

[0064] 3) The motor 11 in the power assembly 5 is started. The motor 11 transmits the rotational force to the flexible transmission shaft 15 through the coupling 12. The flexible transmission shaft 15 transmits the power to the distal end, driving the inner blade to rotate at a high speed, and cooperates with the outer blade to form a special dynamic shearing structure, which can cut the large thrombus 21 into thrombus fragments 22;

[0065] 4) During the thrombus chopping process, the pusher 10 is pushed forward, and the pusher pushes the thrombus cutting assembly 8 forward as a whole by 1 mm, and the inner blade 17 and the outer blade 18 are pushed out of the distal end port of the thrombus removal catheter 7, and the whole thrombus 21 close to the thrombus is chopped into smaller fragments;

[0066] 5) The negative pressure in the thrombus removal catheter 7 is used to draw the thrombus debris 22 into the collection tank 4, thereby completing the removal of the thrombus.

[0067] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A mechanical thrombus removal device, characterized in that: It includes a collecting tank, a thrombus removal catheter, a thrombus cutting assembly and a guide wire. The interior of the collecting tank is in a negative pressure state and is connected to the thrombus removal catheter, that is, the interior of the thrombus removal catheter is in a negative pressure state; The thrombus cutting assembly comprises an inner blade, an outer blade, a flexible transmission shaft and a power assembly for driving the flexible transmission shaft to rotate. The outer blade is slidably mounted on the head of the thrombus removal catheter, and the flexible transmission shaft drives the inner blade to rotate inside the outer blade. The outer blade is cylindrical, and a first cutting edge inclined inward is provided at the front end; the inner blade is a sheet-like structure, and is restricted in the outer blade by a retaining ring; a second cutting edge is provided on both sides of the front end of the inner blade, and the rear end of the inner blade is fixedly connected to the flexible transmission shaft; during the rotation of the inner blade, the second cutting edge and the first cutting edge form a shearing structure; The retaining ring is a convex-shaped structure, the first retaining surface at the front end is in contact with the rear end surface of the inner blade, and the second retaining surface at the rear end of the retaining ring is in contact with and fixedly connected to the rear end surface of the outer blade to prevent the inner blade from moving backwards; The power assembly is provided with a pusher, which can drive the inner blade and the outer blade to extend out from the head of the thrombus removal catheter; The thrombus removal catheter has a first cavity in the middle for accommodating a flexible transmission shaft, and a second cavity on the outer wall for accommodating a guide wire; the first cavity is used to accommodate the thrombus removal component and to aspirate thrombus debris, and the second cavity is used to pass the guide wire; The power assembly includes a housing, a motor bracket and a motor. The motor is mounted on the motor bracket and connected to a flexible transmission shaft through a coupling. The motor bracket is slidably mounted in the housing, and a pusher is mounted on the upper end of the motor bracket to push the motor bracket to move.

2. A mechanical thrombus removal device according to claim 1, characterized in that: A developing ring is fixed on the inner side of the head of the thrombus removal catheter, a boss is arranged on the inner wall of the developing ring, a guide groove is arranged on the outer wall of the outer blade, and the boss is slidably matched with the guide groove.

3. A mechanical thrombus removal device according to claim 1, characterized in that: A metal braided structure is arranged inside the tube wall of the thrombus removal catheter, and is formed by interlacing and braiding a plurality of metal wires.

4. A mechanical thrombus removal device as claimed in claim 3, characterized in that: The length of the thrombus removal catheter is 1.5m~2.5m, the inner diameter of the first cavity is 1.5mm~2.8mm, and the inner diameter of the second cavity is 0.35~0.5mm.

5. The mechanical thrombus removal device according to claim 1, characterized in that: The flexible transmission shaft is formed by winding a plurality of metal filaments, and the interior of the flexible transmission shaft is hollow or a metal wire can be inserted therein.

6. The mechanical thrombus removal device according to claim 1, characterized in that: The tail of the thrombus removal catheter is connected to the power assembly and the collection tank through a three-way seal, the first port of the seal is connected to the collection tank through a suction catheter, the second port is connected to the tail of the thrombus removal catheter, and the third port is connected to the power assembly, and the caliber of the third port is consistent with the outer diameter of the flexible transmission shaft.

7. A mechanical thrombus removal device according to claim 6, characterized in that: The first interface of the collection tank is connected to a negative pressure generator through a pipeline, and the second interface is connected to the sealing member through the suction conduit.

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