CN108143464A - Thrombectomy Catheter and Thrombectomy for Thrombectomy Catheter - Google Patents

Abstract

The invention provides a thrombus removal catheter, which comprises: the blocking sheath comprises a sheath tube, the distal end of the sheath tube is provided with a balloon, the proximal end of the sheath tube is connected with a handle, at least two cavities are arranged in the sheath tube, the first cavity communicates the inner cavity of the balloon with a balloon filling joint on the handle, and the sheath tube on the balloon side is provided with a developing mark; the proximal end of the second cavity is communicated with a negative pressure suction device which is connected with the handle, and the handle is also provided with an opening part which is axially communicated with the second cavity; the dilator can extend into the second cavity of the sheath tube from the opening part of the handle; can follow the embolectomy ware that the opening of handle stretched into in the second cavity to including the outer tube and the inner tube of coaxial cover establishing to and the piece is got to dense netted, and dense netted one end of getting the piece is continuous with the distal end of inner tube, and the piece other end is got to dense netted and is linked to each other with the distal end of outer tube, and the pull inner tube can make the piece inflation or lax of getting the piece is got to dense netted. The thrombus removal catheter can effectively improve the thrombus removal rate and reduce the blood loss.

Description

Thrombectomy Catheter and Thrombectomy for Thrombectomy Catheter

technical field

The invention relates to the technical field of thrombectomy, in particular to a thrombus retrieval catheter and a thrombus retriever used for the thrombus retrieval catheter.

Background technique

Thromboembolic diseases include arterial embolism, arterial thrombosis, and venous thromboembolism. Existing treatments mainly include angiotomy, catheter-based thrombolysis, and percutaneous mechanical thrombectomy. Surgery requires anatomical separation and incision of blood vessels, such as femoral artery, femoral vein or brachial artery incision, etc. With the development of endovascular interventional technology and the innovation of materials, this open surgical method is gradually replaced by minimally invasive interventional endovascular treatment , that is, catheter-based thrombolysis and percutaneous mechanical embolectomy. Catheter-based thrombolysis has a high risk of thrombolytic drug bleeding, and the surgical indications are extremely strict. A large number of patients have contraindications for catheter-based thrombolysis. disease, so many patients do not benefit from it.

Stent-type thrombectomy is a newly emerged mechanical thrombectomy method. This method is to send a stent-type thrombectomy device to the vascular embolism through the catheter and release it with the assistance of medical imaging technology. The thrombus retriever expands by itself, and relies on its own expansion force to engage with the thrombus, and then retracts the thrombus retriever to take out the thrombus.

Chinese invention patent CN103417257B discloses a catheter for intracranial vascular thrombus removal. The distribution density of the spiral mesh ring units of the catheter is different. The distal end is denser, while the proximal end is relatively sparse, which can effectively prevent small thrombus from falling off. . Chinese invention patent CN103997976A discloses a thrombectomy cage with an elongated axis and a circumference, including elongated members jointly defining a plurality of open cells, and the thrombectomy cage can effectively remove emboli. Chinese invention patent CN105726088A discloses a thrombus removal device, which includes a net-shaped self-expanding stent and a core wire. The expanded state of the stent is cylindrical, with an opening at the proximal end and a closed distal end. Embedded in the axial mesh of the stent, the generated thrombus fragments enter the interior through the proximal opening of the stent and are collected by the closed distal end.

As mentioned above, the current stent-type thrombus retriever or thrombus retrieval catheter is limited by its structure. It simply uses sparse stent rods to capture the thrombus or negative pressure suction, and pulls the thrombus to take the thrombus out of the body. , The force of the stent-type thrombus retriever or thrombus retrieval catheter on the thrombus is not uniform, the thrombus is easy to fall off from the thrombus retriever, or thrombus fragments are generated to block the distal blood vessel, or enter other blood vessels, long-term negative pressure It can also cause excessive blood loss. In addition, the current stent-type thrombus retriever or thrombus retrieval catheter is not effective for old thrombus and large-scale embolism. Based on existing medical knowledge, deep vein thrombosis often has a large volume, and the thrombus in the acute phase is soft and fragile; arterial thrombosis often has a small volume, and the thrombus in the acute phase has a soft texture, and old thrombus often adheres to the vessel wall. At present, the stent-type embolectomy catheter with sparse structure is usually developed for arterial thrombosis, and the effect is often not ideal for large-volume venous thrombosis. Therefore, there is a need for a thrombectomy catheter that is easy to remove the thrombus.

Contents of the invention

In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a thrombus retrieval catheter and a thrombus retriever for the thrombus retrieval catheter, which are used to solve the problem of thrombus shedding, spillage and blood loss when the stent retriever is used in the prior art. Too many questions.

In order to achieve the above purpose and other related purposes, the present invention provides a thrombectomy catheter, which includes:

The blocking sheath includes a sheath tube, the distal end of the sheath tube is provided with a balloon, the proximal end of the sheath tube is connected with a handle, and at least two axially extending cavities are arranged in the sheath tube, the distal end of the first cavity is connected to the The inner cavity of the balloon communicates, the proximal end of the first cavity communicates with the balloon filling joint connected to the handle, and a developing mark is provided on the sheath on the side of the balloon; the proximal end of the second cavity The end communicates with the negative pressure suction device connected to the handle, and the handle is also provided with an opening in axial communication with the second cavity;

A dilator, the outer diameter of the dilator matches the inner diameter of the second cavity of the sheath, and can be inserted into the second cavity of the sheath from the opening of the handle, and the distal end of the dilator passes through the sheath passing through the second lumen of the tube and blocking the second lumen of the sheath;

A thrombus retriever, including an outer tube and an inner tube coaxially sleeved, and an expandable mesh-shaped thrombus remover, and both ends of the inner tube are exposed outside the two ends of the outer tube, and the inner tube can be opposite to the outer tube. The tubes can move axially and can also be fixed with each other. One end of the dense mesh plug-retrieving part is connected with the distal end of the inner tube, and the other end of the dense-net-shaped plug-removing part is connected with the distal end of the outer tube. Pulling the inner tube can make the tight The mesh thrombus remover expands or relaxes; the thrombus remover can extend into the second cavity from the opening of the handle, and the distal end of the outer tube passes through the second cavity, and the proximal end of the outer tube exposed outside the opening of the handle.

Preferably, a connection buckle is provided at the opening of the handle, a handle is provided at the proximal end of the dilator, and a connection part is provided on the handle to fit and fix with the connection buckle.

Preferably, the material of the balloon is thermoplastic elastomer such as natural latex, synthetic rubber, silica gel or polyurethane.

Preferably, the dense mesh-shaped bolt-removing member is braided by superelastic memory nickel-titanium alloy wire mixed with platinum-iridium alloy wire, gold wire or stainless steel wire, and the platinum-iridium alloy wire, gold wire or stainless steel wire are used under X-ray machines. development.

Preferably, a handpiece is connected to the proximal end of the outer tube, and the handpiece is provided with a positioning part for locking the inner tube.

Preferably, a pull handle is connected to the proximal end of the inner tube.

Preferably, the sheath tube, the inner tube and the outer tube are all made of polyamide thermoplastic elastomer.

Preferably, the dilator is made of thermoplastic elastomer, and the thermoplastic elastomer is filled with barium sulfate, bismuth oxide or bismuth oxychloride containing developer material.

Preferably, the distal ends of the sheath and the inner tube are tapered.

The present invention also provides a thrombus retriever for a thrombectomy catheter. The thrombus retriever includes an outer tube and an inner tube that are coaxially sleeved, and an expandable dense mesh thrombus remover, and the two ends of the inner tube Both ends are exposed outside the two ends of the outer tube, and the inner tube can move axially relative to the outer tube. One end of the dense mesh bolt-removing part is connected with the distal end of the inner pipe, and the other end of the dense mesh-shaped bolt-removing part is connected to the distal end of the outer pipe. The end is connected, and the inner tube can be pulled to expand or relax the dense mesh thrombus retrieval device.

Preferably, the dense mesh-shaped bolt-removing member is braided by mixing platinum-iridium alloy wire, gold wire or stainless steel wire in superelastic memory nickel-titanium alloy wire.

Preferably, a handpiece is connected to the proximal end of the outer tube, and the handpiece is provided with a positioning part for locking the inner tube.

Preferably, the distal end of the inner tube is tapered.

As mentioned above, the thrombus retrieval catheter and the thrombus retriever used for the thrombus retrieval catheter of the present invention have the following beneficial effects: the blood flow is blocked by filling the balloon at the distal end of the sheath tube, and the thrombus is surrounded in a dense mesh for retrieval. Between the thrombus and the balloon, it is easy to remove the thrombus. At the same time, the dense mesh thrombus removal member can allow blood to pass through the upper hole, which can effectively prevent the thrombus from overflowing to other parts of the blood vessel during the thrombus removal operation. The thrombus retrieval device with dense mesh and blocking balloon cooperates with negative pressure suction to minimize blood loss; the thrombus retriever has a thinner inner tube and a thinner outer tube, which can reach the thrombus Deeper position; suitable for thrombus removal of large and medium-sized blood vessels, including relatively old lesions, especially suitable for absorbing thrombus on limbs, such as thrombus with large capacity in veins; the thrombus removal catheter of the present invention is passive thrombus removal The device is low in cost and simple in operation, and can greatly reduce the cost of thrombectomy.

Description of drawings

Fig. 1 is a schematic view showing that the dilator of the present invention is inserted in a blocking sheath.

FIG. 2 shows a cross-sectional view along line AA in FIG. 1 .

Fig. 3 is a schematic diagram of the blocking sheath of the present invention.

Fig. 4 is a schematic view of the dilator of the present invention.

Fig. 5 is a schematic diagram of the thrombus retriever of the present invention.

FIG. 6 is a cross-sectional view along line BB in FIG. 5 .

Fig. 7 is a schematic diagram showing that the thrombus retriever of the present invention is worn in the blocking sheath and is in a relaxed state.

Fig. 8 is a schematic view showing that the thrombus retriever of the present invention is inserted in the blocking sheath and is in an expanded state.

Component designation description

1 dilator

2 Develop mark

3 balloons

4 Sheaths

5 Negative pressure suction device

6 handles

7 Balloon inflation connector

8 handle

9 two-way

10 connecting pipe

11 Connection buckle

12 Connecting part

121 notch

13 Dense Mesh Removal Parts

14 outer tube

15 Handpieces

16 inner tube

17 pull handle

Detailed ways

The implementation of the present invention will be illustrated by specific specific examples below, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

See Figures 1 through 8. It should be noted that the structures, proportions, sizes, etc. shown in the drawings attached to this specification are only used to match the content disclosed in the specification, for those who are familiar with this technology to understand and read, and are not used to limit the implementation of the present invention. Limiting conditions, so there is no technical substantive meaning, any modification of structure, change of proportional relationship or adjustment of size, without affecting the effect and purpose of the present invention, should still fall within the scope of the present invention. within the scope covered by the disclosed technical content. At the same time, terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description and are not used to limit this specification. The practicable scope of the invention and the change or adjustment of its relative relationship shall also be regarded as the practicable scope of the present invention without any substantial change in the technical content.

For the convenience of description, in this manual, along the length direction of the thrombectomy catheter, when in use, the end away from the operator is defined as the distal end, and the end held by the operator is defined as the proximal end.

As shown in Figures 1 to 8, the present invention provides a thrombectomy catheter, which includes:

The blocking sheath, as shown in Figure 3, includes a sheath tube 4, the distal end of the sheath tube 4 is provided with a balloon 3, the proximal end of the sheath tube 4 is connected with a handle 6, and the sheath tube 4 is provided with at least two axial Extended cavity, the distal end of the first cavity communicates with the inner cavity of the balloon 3, the proximal end of the first cavity communicates with the balloon filling joint 7 connected to the handle 6, and the two sides of the balloon 3 communicate with each other. The side sheath tube 4 is provided with a development mark 2; the proximal end of the second cavity communicates with the negative pressure suction device 5 connected to the handle 6, and the handle 6 is also provided with the second The opening part of the axial communication of the cavity;

The dilator 1, the outer diameter of the dilator 1 matches the inner diameter of the second cavity of the sheath tube 4, and can be inserted into the second cavity of the sheath tube 4 from the opening of the handle 6, the dilator 1 The distal end passes through the second cavity of the sheath tube 4 and blocks the second cavity of the sheath tube 4;

The thrombus remover, as shown in Figure 5, includes an outer tube 14 and an inner tube 16 coaxially sleeved, and an expandable dense mesh thrombus removal member 13, and both ends of the inner tube 16 are exposed to the outer tube 14. In addition to the two ends, and the inner tube 16 can move axially relative to the outer tube 14 and can also be fixed relative to each other, one end of the dense mesh bolt removal part 13 is connected to the far end of the inner pipe 16, and the dense mesh shape bolt removal part 13 is connected to the other end. One end is connected with the distal end of the outer tube 16, and pulling the inner tube 16 can expand or relax the mesh thrombus remover 13; the thrombus remover can be inserted into the second cavity from the opening of the handle 6, and the outer The distal end of the tube 14 passes through the second cavity, as shown in FIGS. 7 and 8 , and the proximal end of the outer tube 14 is exposed outside the opening of the handle 6 .

The thrombus retrieval catheter of the present invention has three components, which are the above-mentioned blocking sheath, the dilator 1 and the above-mentioned thrombus retriever, and the balloon 3 at the distal end of the sheath tube 4 is filled to serve as a blockage at the proximal end of the thrombus, so as to block the thrombus. The blood flow is cut off, and the thrombus can be surrounded between the dense mesh thrombus removal part 13 and the balloon 3, which is easy to remove the thrombus. 13 Due to its compactness, during the thrombus removal operation, the thrombus is easy to form a stopper film on the surface of the dense mesh thrombus removal member 13, which can effectively prevent the thrombus from crossing the dense mesh thrombus removal member 13 to other parts during the removal process. The extravasation of blood vessels, the dense mesh thrombus removal device and blocking balloon thrombus removal combined with negative pressure suction can reduce blood loss to a minimum, and are especially suitable for absorbing large-capacity thrombus in veins.

In this embodiment, the opening of the above-mentioned handle 6 is provided with a connecting buckle 11, and the dilator 1 is provided with a connecting portion 12 that is fixed with the connecting buckle 11, and is fixed by the connecting portion 12 and the connecting buckle 11. The dilator 1 and the blocking sheath are fixed to facilitate penetration into blood vessels. In this embodiment, a raised portion is provided on the connecting buckle 11, and a notch 121 is provided on the connecting portion 12. Engaging in the notch 121 realizes the positioning and connection of the dilator 1 and the blocking sheath. The cooperation between the protrusion and the notch 121 also facilitates the separation of the two, and the dilator 1 is easily pulled out from the blocking sheath.

The connection between the above-mentioned handle 6 and the dilator 1 is not limited to the cooperation between the above-mentioned connecting buckle 12 and the connecting part 11, it can also be realized by setting a rotatable positioning part, and the dilator can be locked after the positioning part is tightened. The above-mentioned handle 6 can also lock the thrombus retriever through the rotating positioning part.

In order to facilitate insertion of the dilator 1 , a handle 8 is provided at the proximal end of the dilator 1 . The operator can hold the handle 8 and insert the dilator 1 into the sheath 4 through the opening of the handle 6 . In order to facilitate medical imaging, the dilator 1 in this embodiment is made of thermoplastic elastomer such as polyethylene or polyurethane, and the thermoplastic elastomer is filled with barium sulfate, bismuth oxide or bismuth oxychloride containing developer materials.

In this embodiment, the sheath tube 4 in the blocking sheath is a double-lumen structure or a multi-lumen structure, one of which is the first cavity used as a passage for filling the balloon 3, and the other cavity is the second cavity As a working chamber, it is used to pass the above-mentioned dilator 1 or the above-mentioned thrombus retriever or other medical devices into and out of blood vessels, and the material of the sheath tube 4 is polyurethane or polyamide thermoplastic elastomer. In this embodiment, the material of the balloon 3 is a thermoplastic elastomer such as natural latex, synthetic rubber, silica gel or polyurethane, and a contrast agent is injected through the balloon filling cavity joint 7 on the handle 6 to fill and expand the compliant balloon to form a barrier. Cut off blood circulation. In order to facilitate the extraction of thrombus, the above-mentioned negative pressure suction device 5 is connected to the handle 6 through the connecting pipe 10 in this embodiment, and the negative pressure suction device 5 is also provided with a two-way 9, which is convenient to be connected with the electric negative pressure suction device, forming Suction the negative pressure so that the thrombus can flow from the blocking sheath into the collection device of the negative pressure suction device 5 more efficiently.

In the above-mentioned thrombus remover in this embodiment, the dense mesh-shaped thrombus remover 13 is woven by superelastic memory nickel-titanium alloy wire, and mixed with a certain amount of platinum-iridium alloy wire, gold wire or stainless steel wire for X-ray Under-machine imaging, which allows blood to flow through the dense mesh thrombus removal device during thrombectomy, can effectively prevent thrombus and embolus from overflowing to other parts of the blood vessel during the removal process; the dense mesh thrombus removal device At the same time as the thrombus is combined with negative pressure suction, it can effectively reduce blood loss and improve the effect of thrombus suction. The superelastic memory nickel-titanium alloy wire used in the dense mesh-like bolt-taking part in this embodiment is very thin, and the aperture of the woven mesh is about 0.3-1.0mm, that is to say, the dense mesh of the present embodiment The thrombus-removing part is a dense mesh part, which can not only allow blood to pass through, but also prevent thrombus from passing through. Both the outer tube 14 and the inner tube 16 are made of polyamide thermoplastic elastomer. The material of the entire thrombus retriever is soft, which reduces the damage to the vascular intima during the thrombectomy process.

In order to facilitate the expansion and relaxation of the dense mesh bolt removing part, a handpiece 15 is connected to the proximal end of the above-mentioned outer tube 14 in this embodiment. As shown in FIG. positioning department. In this embodiment, the handpiece 15 can be used as a handle, which is convenient for the operator to take the thrombus remover. The positioning part in the hand piece 15 can position the inner tube 16 and the outer tube 14, and keep the mesh thrombus removing part 13 in an expanded state, so as to facilitate pulling the thrombus into the blocking sheath. The positioning part can be a rotary or switch-type locking piece, and the inner tube and the outer tube can be locked by rotating or switching.

As shown in Figures 5 and 6, in this embodiment, the inner tube 16 is installed in the outer tube 14, and the length of the inner tube 16 is longer than the length of the outer tube 14, and both ends of the inner tube 16 are located outside the outer tube 14. One end of the dense mesh thrombus removing part 13 is connected to the distal end of the inner tube 16, the other end of the dense mesh thrombus removing part 13 is connected to the distal end of the outer tube 14, and the distal end of the inner tube 16 is changed by pulling the inner tube 16 The relative distance from the distal end of the outer tube is used to expand and relax the dense mesh thrombus removing part 13. If the inner tube is pulled in the direction of the arrow in Fig. 5, the dense mesh thrombus removing part expands, otherwise it relaxes.

In order to facilitate the drawing of the inner tube, as shown in FIG. 5 , the proximal end of the inner tube 16 in this embodiment is connected with a drawing handle 17 . In order to facilitate the thrombus retriever to pass through the thrombus and run to the distal end of the thrombus, the distal end of the inner tube 16 in this embodiment is rounded and has a certain taper, that is, its end is tapered.

The specific process of using the above-mentioned thrombus removal catheter to extract thrombus in the blood vessel is as follows:

Puncture and intubate the blood vessel, and after knowing the position of the thrombus and the surrounding blood vessels through arterial or venography, firstly, the above-mentioned dilator 1 is inserted in the second cavity of the sheath tube 4, as shown in Figure 1 and Figure 2. The device 1 is placed in the blocking sheath, and then under the guidance of the guide wire, guide the above-mentioned sheath tube 4 to the proximal end of the thrombus; use physiological saline or other suitable medicinal liquid to connect the balloon lumen joint 7 to fill the balloon 3 to the The inner diameter of the blood vessel is such that the balloon blocks the blood vessel proximal to the thrombus and blocks the blood flow; withdraw the dilator 1 from the blocking sheath, and place the thrombus retriever along the guide wire, as shown in Figure 7, the thrombus retriever The dense mesh thrombus removal part 13 passes through the thrombus and is placed on the distal end of the thrombus; the inner tube 16 of the thrombus remover is pulled outward, as shown in Figure 8, the dense mesh thrombus removal part 13 expands, and the inner tube 16 Locking with the outer tube 14, keeping the dense mesh thrombus removing part 13 in an expanded state; pulling the outer tube 14 outward to draw the thrombus into the sheath tube 4 of the blocking sheath, and simultaneously, the thrombus is discharged into the negative through negative pressure suction. In the suction device 5, and when the thrombus is pulled, the blood can pass through the dense mesh thrombus removal part 13 to reduce the blood loss, but the massive thrombus will be sucked out with the suction; The balloon on the blocking sheath is moved to the next thrombus for thrombus removal. The thinner tip and tube body of the thrombus retriever in this embodiment can reach the deeper position of the thrombus.

In summary, the thrombus retrieval catheter and the thrombus retriever used for the thrombus retrieval catheter of the present invention block the blood flow by filling the balloon at the distal end of the blocking sheath. During the thrombectomy process, the soft thrombus retriever, Reduce the damage of the intima of the blood vessel; the dense mesh thrombus removal piece can allow blood to pass through the holes on it, and can effectively prevent the thrombus from overflowing to other parts of the blood vessel during the thrombus removal operation. The dense mesh thrombus removal piece Thrombectomy is combined with negative pressure suction, which facilitates thrombus removal and minimizes blood loss; the inner tube of the thrombus retriever has a thinner tip and tube body, which can reach a deeper position in the thrombus; it is suitable for the removal of large and medium-sized blood vessels Thrombus, including relatively old lesions; the present invention is a passive thrombus removal device with low cost and simple operation, which can greatly reduce the cost of thrombus removal surgery; it can remove large-capacity thrombus with high efficiency, reduce valve damage, and use less thrombolytic drugs. Less blood loss, less trauma, faster recovery period. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial application value.

The above-mentioned embodiments only illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed in the present invention shall still be covered by the claims of the present invention.

Claims (13)

1. A thrombectomy catheter, characterized in that, comprising: The blocking sheath includes a sheath tube, the distal end of the sheath tube is provided with a balloon, the proximal end of the sheath tube is connected with a handle, and at least two axially extending cavities are arranged in the sheath tube, and the first cavity connects the ball The inner cavity of the balloon communicates with the balloon filling joint connected to the handle, and a developing mark is set on the sheath tube on the side of the balloon; the proximal end of the second cavity is connected to the negative pressure pump connected to the handle. The suction device is connected, and the handle is also provided with an opening in axial communication with the second cavity; A dilator, the outer diameter of the dilator matches the inner diameter of the second cavity of the sheath, and can be inserted into the second cavity of the sheath from the opening of the handle, and the distal end of the dilator passes through the sheath passing through the second lumen of the tube and blocking the second lumen of the sheath; A thrombus retriever, including an outer tube and an inner tube coaxially sleeved, and an expandable mesh-shaped thrombus remover, both ends of the inner tube are exposed outside the two ends of the outer tube, and the inner tube can be opposite to the outer tube Moving along the axial direction can also be fixed with each other. One end of the dense mesh bolt removal part is connected to the distal end of the inner tube, and the other end of the dense mesh bolt removal part is connected to the distal end of the outer pipe. Pulling the inner pipe can make the dense mesh The thrombus remover expands or relaxes; the thrombus remover can extend into the second cavity from the opening of the handle, and the distal end of the outer tube passes through the second cavity, and the proximal end of the outer tube is exposed on the outside of the opening of the handle. 2. The thrombectomy catheter according to claim 1, characterized in that: the handle is provided with a connection buckle, and the proximal end of the dilator is connected with a handle, and the handle is provided with the connection clip. Snap-fit secure connection. 3. The thrombectomy catheter according to claim 1, wherein the material of the balloon is thermoplastic elastomer such as natural latex, synthetic rubber, silica gel or polyurethane. 4 . The thrombectomy catheter according to claim 1 , characterized in that: the dense mesh thrombus removal member is braided by superelastic memory nickel-titanium alloy wire mixed with platinum-iridium alloy wire, gold wire or stainless steel wire. 5 . The thrombectomy catheter according to claim 1 , wherein a hand piece is connected to the proximal end of the outer tube, and the hand piece is provided with a positioning portion for locking the inner tube. 6. The thrombectomy catheter according to claim 5, wherein a pull handle is connected to the proximal end of the inner tube. 7. The thrombectomy catheter according to claim 1, wherein the sheath tube, the inner tube and the outer tube are all made of polyurethane or polyamide thermoplastic elastomer. 8 . The thrombectomy catheter according to claim 1 , wherein the dilator is made of thermoplastic elastomer, and the thermoplastic elastomer is filled with barium sulfate, bismuth oxide or bismuth oxychloride, which contains contrasting agent. 9. The thrombectomy catheter according to claim 1, wherein the distal ends of the sheath tube and the inner tube are tapered. 10. A thrombus retriever for a thrombectomy catheter, characterized in that: the thrombus retriever includes an outer tube and an inner tube coaxially sleeved, and an expandable dense mesh thrombus remover, and the inner tube Both ends are exposed outside the two ends of the outer tube, and the inner tube can move axially relative to the outer tube. One end of the dense mesh bolt removal part is connected to the distal end of the inner pipe, and the other end of the dense mesh bolt removal part is connected to the outer tube. The distal end is connected, and the inner tube can be pulled to expand or relax the dense mesh thrombus retrieval device. 11. The thrombus retriever for thrombus retrieval catheter according to claim 10, characterized in that: the dense mesh thrombus retrieval member is made of superelastic memory nickel-titanium alloy wire mixed with platinum-iridium alloy wire, gold wire or stainless steel Woven from silk. 12. The thrombus retriever for thrombus retrieval catheter according to claim 10, characterized in that: the proximal end of the outer tube is connected with a handpiece, and the handpiece is provided with a lock for locking the inner tube. positioning department. 13. The thrombus retriever for a thrombus retrieval catheter according to claim 10, characterized in that: the distal end of the inner tube is tapered.