A retrievable arterial flow reduction device

Abstract

The application provides a recyclable arterial blood flow reduction device, relates to the technical field of interventional medical instruments, and comprises a stent part, a recycling part and a pushing assembly. The stent part comprises a stent body which is wide in the middle and narrow at both ends, and a proximal rod body connected to the proximal end of the stent body. The recycling part comprises a recycling hook connected to the proximal rod body, and a recess is arranged on the side wall of the recycling hook. The pushing assembly comprises a long sheath tube, a sleeve loop catheter slidingly arranged on the long sheath tube, and a clamping piece arranged on the sleeve loop catheter. After the sleeve loop catheter is sleeved on the recycling hook, the clamping piece is connected with the recess, and the sleeve loop catheter is pulled out to take out the blood flow reduction device. The metal elastic sheet is arranged, after the sleeve loop catheter is sleeved on the recycling hook, the recess and the clamping piece are connected together at least in the axial direction, the stent body is moved to the proximal end by pulling the sleeve loop catheter, and the problem that the stent body is difficult to be connected again and the blood flow reduction device is difficult to be taken out is conveniently solved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of interventional medical devices, and particularly relates to a retrievable arterial blood flow reducing device. BACKGROUND

[0002] Ischemic stroke caused by thrombus in the cerebral blood vessel is a refractory disease that seriously endangers human health and life safety, and the thrombus in the blood vessel can hinder the normal flow of blood in the brain, causing local brain tissue ischemia and hypoxia. If the ischemic time is too long, nerve cells will be damaged or even die due to lack of nutrients and oxygen. The number of people who die of stroke in China each year has exceeded that of tumor and cardiovascular disease, becoming the first cause of death. In order to solve the problem of ischemic stroke death caused by thrombus, the method of interventional surgery thrombectomy has become a development trend in recent years.

[0003] After the thrombus is removed by interventional surgery, blood flow will enter the originally blocked blood vessel, restoring the blood supply to the brain. It is found in clinical practice that the recovery effect of 2a grade is better than that of 3 grade after intracranial blood vessel recanalization, because after the blood vessel recanalization, the blood flow is reperfused, and the flow is larger than that before recanalization, which causes capillary damage and is easy to form cerebral hematoma infarction. Therefore, a flow reducing device is arranged at the thrombus, and the flow reducing device is left in the blood vessel after the surgery, so that the flow reducing device keeps the blood flow small in 2-3 weeks, and then the flow reducing device is withdrawn after the blood vessel fully recovers.

[0004] In the prior art, because the flow reducing device needs to be left in the blood vessel for a period of time, if the withdrawal device is left together with the flow reducing device, it will affect the patient's activities, and if the withdrawal device is separated from the flow reducing device, it will be difficult to connect with the flow reducing device again when the surgery is taken out, because the space in the blood vessel is narrow, making it difficult to take out the flow reducing device.

[0005] Therefore, it is necessary to provide an improved technical solution for the above-mentioned deficiencies in the prior art. SUMMARY

[0006] The purpose of the present application is to provide a retrievable arterial blood flow reducing device to solve the problem that it is difficult to connect with the flow reducing device again when the flow reducing device is taken out, and the flow reducing device is difficult to take out.

[0007] In order to achieve the above-mentioned purpose, the present application provides the following technical solution:

[0008] A retrievable arterial blood flow reducing device, comprising a stent part, a retrieval part and a pushing assembly;

[0009] The stent part comprises a stent body and a proximal rod body connected to the proximal end of the stent body;

[0010] The recovery part comprises a recovery hook connected to the proximal rod body, and a recess is arranged on the side wall of the recovery hook;

[0011] The pushing assembly comprises a long sheath tube, a sleeve ring catheter slidingly arranged on the long sheath tube, and a clamping piece arranged on the sleeve ring catheter.

[0012] Preferably, the recess is a clamping groove on the side wall of the proximal rod body, and the clamping piece comprises a metal fixing ring arranged on the inner wall of the sleeve ring catheter and a metal spring sheet arranged on the inner wall of the metal fixing ring.

[0013] Preferably, one end of the metal spring sheet is connected to the inner wall of the metal fixing ring, and the other end extends towards the proximal end and forms an angle with the inner wall of the sleeve ring catheter.

[0014] Preferably, the proximal rod body is provided with external threads, the recovery hook is provided with an internal thread groove, and the recovery hook is threadedly connected to the proximal rod body.

[0015] Preferably, the middle part of the stent body is arranged in an equal-diameter structure.

[0016] Preferably, the stent part further comprises a distal rod body arranged at the distal end of the stent body, and the distal rod body is annular.

[0017] Preferably, the recovery hook is a component made of a developing material.

[0018] Preferably, the inner wall of the stent body is provided with a coating film, the coating film covers the distal end part of the inner wall of the stent body, and the coating film is combined with the inner wall of the stent body by means of melting, suturing or spraying.

[0019] Preferably, the coating film is a PTFE film or an ePTFE film.

[0020] Preferably, the coating film is provided with a phosphatidylcholine coating.

[0021] Beneficial effects:

[0022] (1) By arranging the recess and the clamping piece, after the sleeve ring catheter is sleeved on the recovery hook, the recess and the clamping piece are connected together at least in the axial direction, and the stent body can be moved towards the proximal end by pulling the sleeve ring catheter, thereby conveniently solving the problem that it is difficult to connect the stent body again and the problem that the flow reduction device is difficult to take out.

[0023] (2) The middle part of the stent body is provided with an equal-diameter structure, so that the width of the middle part of the stent body is constant, and the middle part of the stent body is parallel to the length direction of the blood vessel, and the equal-diameter structure is provided to increase the contact area between the middle part of the stent body and the inner wall of the blood vessel, thereby improving the stability of the stent body;

[0024] (3) The stent body is provided with a covering film at the distal end, which can block the blood flow, so that the blood flow flows out at the opening of the distal end of the stent, thereby limiting the blood flow. BRIEF DESCRIPTION OF DRAWINGS

[0025] The drawings accompanying the specification of this application form a part thereof, serve to provide further understanding of the application, and together with the description of the exemplary embodiments of the application, serve to explain the application, and do not constitute an improper limitation on the application. Among them:

[0026] Figure 1 It is a front view structural schematic diagram of the stent body in the embodiment of the application, which is a hollow stent and is in a covering film state;

[0027] Figure 2 It is a structural schematic diagram of the stent body in the embodiment of the application, which is a dense net stent and is in a covering film state;

[0028] Figure 3 It is a structural schematic diagram of the stent body in the embodiment of the application, which is a dense net stent;

[0029] Figure 4 It is a structural schematic diagram of the stent body in the embodiment of the application, which is a dense net stent;

[0030] Figure 5 It is a structural schematic diagram of the stent body in the embodiment of the application, which is a dense net stent;

[0031] Figure 6 It is a structural schematic diagram of the stent body in the embodiment of the application, which is a dense net stent;

[0032] Figure 7 It is a structural schematic diagram of the stent body in the embodiment of the application, which is a dense net stent;

[0033] Figure 8 It is a structural schematic diagram of the stent body in the embodiment of the application, which is a dense net stent;

[0034] Figure 9 It is a structural schematic diagram of the stent body in the embodiment of the application, which is a dense net stent;

[0035] In the figure: 1, support part; 11, support body; 12, proximal rod body; 121, external thread; 13, distal rod body; 2, recovery hook; 21, internal thread groove; 22, recess; 3, push assembly; 31, long sheath tube; 32, collar catheter; 33, clamping piece; 331, metal fixing ring; 332, metal elastic sheet; 4, film covering; 5, developing point. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be described below in a clear and complete manner. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments in the present application belong to the scope of protection of the present application.

[0037] In the description of the present application, it should be understood that the orientation description, such as the orientation or position relationship indicated by up, down, front, back, left, right, etc., is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as a limitation on the present application.

[0038] In the description of the present application, several meanings are one or more, and multiple meanings are two or more. Greater than, less than, more than, etc. are understood as not including the number itself. Above, below, etc. are understood as including the number itself. If it is described as first, second, etc., it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the sequence of indicated technical features.

[0039] In addition, the terms "first" and "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features limited by "first" and "second" can explicitly or implicitly include one or more features.

[0040] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the term "connection" should be understood broadly, for example, it can be a fixed connection or a movable connection, or a detachable connection or a non-detachable connection, or an integral connection; it can be a mechanical connection, or an electrical connection or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements, indirect communication or the interaction relationship between two elements.

[0041] In the description of the present application, 'before use' refers to the state of the recoverable arterial blood flow reduction device before it is used, before it enters the human body, or before it is in contact with body fluids such as blood, interstitial fluid, etc. in the human body. 'During use' refers to the state of the recoverable arterial blood flow reduction device after it has entered the human body or has been in contact with body fluids such as blood, interstitial fluid, etc. in the human body.

[0042] In the description of the present application, 'gathered state' refers to the state in which the 'branch catheter' is in close contact with each other within a partial length range or within the entire length range.

[0043] In the description of the present application, 'proximal end' refers to the end closer to the operator during the operation, and 'distal end' refers to the end farther from the operator during the operation.

[0044] In the description of the present application, grade 0, grade 1, grade 2a, grade 2b and grade 3 are based on mTICI grading. mTICI refers to the modified cerebral infarction grading system, which is currently an index for evaluating the angiographic results after thrombectomy of patients with vascular occlusive ischemic stroke. It should be noted that grade 2a describes that there is partial blood perfusion (<50%) in the distal ischemic area, and grade 3 describes that the blood flow in the distal ischemic area is completely restored.

[0045] In the description of the present application, 'in vivo environment' refers to the environment below the epidermis of the skin, where body fluids exist, such as the dermis layer and subcutaneous tissue, or the inside of blood vessels and organs, etc.

[0046] The present application will be described in detail below with reference to the embodiments. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0047] The present application is directed to the problem in the prior art that because the flow reduction device needs to be left in the blood vessel for a period of time, if the withdrawal device is left together with the flow reduction device, it will affect the patient's activities, and if the withdrawal device is separated from the flow reduction device, it is difficult to reconnect the withdrawal device and the flow reduction device again during the removal operation due to the narrow space in the blood vessel.

[0048] The present application discloses a recoverable arterial blood flow reduction device, comprising a stent part 1, a recovery part and a pushing assembly 3.

[0049] Reference Figure 1 and Figure 2The stent part 1 comprises a stent body 11 with wide middle part and narrow two ends, and a proximal rod 12 connected to the proximal end of the stent body 11. The stent body 11 is preferably a nickel-titanium laser engraved stent, forming a skeleton structure with hollows. More preferably, the inner side wall of the stent body 11 is coated with a film 4, which can be in the form of hot melting, sewing or spraying. The nickel-titanium laser engraved stent is made of nickel-titanium alloy, which has shape memory function. After being released, the stent body 11 can automatically expand and abut against the inner wall of the blood vessel, realizing the fixation of the stent body 11 and resisting displacement under the flow of blood.

[0050] Referring to Figure 3 In another embodiment of the present application, the distal end of the stent body 11 is a dense mesh stent, which does not allow or only allows blood to seep out.

[0051] In a preferred embodiment, the middle part of the stent body 11 is designed as an equal-diameter structure, and the equal-diameter part has the maximum width, which can better fit the equal-diameter part with the inner wall of the blood vessel, thereby further enhancing the stability of the stent body 11.

[0052] Referring to Figures 1 to 3 The width of the stent body 11 gradually shrinks from the middle part to the two ends, the two ends of the stent body 11 are open, and the middle part is unobstructed, allowing blood flow to pass through. The blood flows into the proximal end of the stent body 11 and flows out of the distal end of the stent body 11. The proximal end of the stent body 11 is funnel-shaped, which is designed to reduce the contact area between the stent body 11 and the blood vessel, reduce endothelialization, and reduce the recovery resistance. It should be noted that the part of the film 4 on the stent body 11 does not allow blood to pass through, so that the blood flow is concentrated at the distal opening. The purpose of this design is to reduce the diameter of the blood flow channel, thereby reducing the blood flow in the blood vessel after initial recovery and protecting the blood vessel. The transition between the middle part and the two ends of the stent body 11 is smooth, avoiding scratching or tearing the blood vessel wall during recovery, reducing the recovery resistance, and facilitating recovery.

[0053] The proximal rod 12 can be integrally formed with the stent body 11, or can be connected by welding, hot melting or other connection methods. The proximal rod 12 is preferably made of stainless steel, which has good strength and toughness and can withstand a certain tensile force and bending. At the same time, the influence of stainless steel on the human body environment is also relatively small. In other embodiments of the present application, the proximal rod 12 is made of nickel-titanium alloy, which has shape memory function and can restore to the initial straight shape after passing through the tortuous intracranial blood vessel, facilitating the placement of the stent body 11, and the nickel-titanium alloy is relatively soft, causing less damage to the blood vessel wall.

[0054] The recovery part comprises a recovery hook 2 connected to the proximal rod 12, and the side wall of the recovery hook 2 is provided with a recess 22.

[0055] Referring to Figures 1 to 4, the push assembly 3 comprises a long sheath tube 31, a sleeve loop catheter 32 slidingly arranged on the long sheath tube 31, and a clamping piece 33 arranged on the sleeve loop catheter 32. After the sleeve loop catheter 32 is sleeved on the recovery hook 2, the clamping piece 33 is hooked with the recovery hook 2, and the sleeve loop catheter 32 is pulled out to take out the flow reducer. The recessed portion 22 is recessed to the inside of the side wall of the recovery hook 2 close to the proximal end. In a specific embodiment, the recessed portion 22 is an annular groove arranged circumferentially along the recovery hook 2. The distal end of the recovery hook 2 is provided with a connecting structure matched with the proximal rod body 12. Specifically, the connecting manner of the recovery hook 2 and the proximal rod body 12 can be screw connection, buckle connection, snare connection, adhesion or welding. It should be noted that, in order to avoid damage to the inner wall of the blood vessel caused by the recovery hook 2, a smooth chamfer is arranged at each corner of the recovery hook 2, and the surface of the recovery hook 2 is smooth to avoid the existence of sharp parts.

[0056] With reference to Figures 1 to 5 , the long sheath tube 31 is made of medical-grade high-molecular materials such as polytetrafluoroethylene (PTFE) and polyurethane (PU). Polytetrafluoroethylene has excellent chemical stability, low friction coefficient and good biocompatibility. When the long sheath tube 31 contacts blood and human tissues, it will not cause obvious chemical reaction and is not easily recognized as a foreign body by the human immune system, and can smoothly flow in the blood vessel. The sleeve loop catheter 32 is arranged in the channel of the long sheath tube 31 in a sliding connection manner. The opening of the sleeve loop catheter 32 can be a circular ring or an elliptical ring. The opening shape is not limited, and only needs to be slightly larger than the proximal end of the recovery hook 2 so that the proximal end of the recovery hook 2 can be inserted.

[0057] With reference to Figure 6 and Figure 7 , the proximal end of the recovery hook 2 is contracted to the middle part to form a bevel surface. After the sleeve loop catheter 32 contacts the bevel surface, the bevel surface guides the sleeve loop catheter 32 to move along the bevel surface, thereby conveniently guiding the recovery hook 2 into the sleeve loop catheter 32. The clamping piece 33 is a component with elasticity, which is preferably a spring piece or an elastic rubber block. After being extruded by the recovery hook 2, the clamping piece 33 deforms. When the clamping piece 33 passes through the recessed portion 22 of the recovery hook 2, the clamping piece 33 restores to allow the clamping piece 33 to be clamped in the recessed portion 22. At this time, the sleeve loop catheter 32 is pulled, the clamping piece 33 abuts against the side wall of the recessed portion 22, the force is transmitted to the recovery hook 2, and then transmitted to the proximal rod body 12 and the stent body 11 in turn, thereby realizing pulling the stent body 11.

[0058] With reference to Figures 1 to 6, use process: when the blood vessel recovers the pressure resistance, only need to carry on the blood vessel puncture, push the long sheath tube 31 to the stent body 11 proximal end position, the sleeve ring catheter 32 first contact with the recovery hook 2, along the recovery hook 2 movement, the front end of the recovery hook 2 extrusion clamping piece 33 let the clamping piece 33 deformation, continue to move let the clamping piece 33 into the recess 22, at least at this time, in the axial direction of the blood vessel, the clamping piece 33 and the recess 22 fixed connection, pull the sleeve ring catheter 32 can pull the stent body 11. Pull the sleeve ring catheter 32, the stent body 11 is pressed into the long sheath tube 31, after all recovery, conveniently solve the problem of difficult to connect the stent body 11 again, leading to the difficulty of removing the flow reducing device.

[0059] In the preferred embodiment of the application, the recess 22 is a clamping groove opened on the side wall of the proximal rod body 12, the clamping piece 33 includes a metal fixing ring 331 provided on the inner wall of the sleeve ring catheter 32, a metal spring 332 provided on the inner wall of the metal fixing ring 331, one end of the metal spring 332 connected to the inner wall of the metal fixing ring 331, the other end extending towards the proximal end and having an angle with the inner wall of the sleeve ring catheter 32; the clamping groove covers the circumference of the side wall of the proximal rod body 12, and is annular. The metal fixing ring 331 is fixed on the inner wall of the sleeve ring catheter 32 by hot melting connection or welding. The shape of the metal fixing ring 331 is matched with the inner wall of the sleeve ring catheter 32, and the metal fixing ring 331 and the metal spring 332 are preferably made of stainless steel, which has strength and toughness, can bear a certain tension and bending, and has less impact on the human body environment. The metal spring 332 deforms when extruded, restores after entering the clamping groove, and abuts against the side wall of the clamping groove to realize fixation in the axial direction of the blood vessel. Preferably, the angle between the metal spring 332 and the inner wall of the sleeve ring catheter 32 is ≤30°, and the purpose of setting the angle is to allow the recovery hook 2 to have a buffer with the metal spring 332, reduce the damage of extrusion to the metal spring 332, and prolong the service life of the metal spring 332.

[0060] Referring to Figure 8 , the metal spring 332 has at least three, and the three metal springs 332 are annularly and equidistantly arranged. The three metal springs 332 are clamped in the recess 22 to realize fixation in the axial direction of the blood vessel.

[0061] Referring to Figure 7 , in another preferred embodiment, the metal spring 332 is a whole piece and annular, which is designed to make the connection between the metal spring 332 and the recess 22 more stable.

[0062] In another embodiment of the present application, the clamping piece 33 can be an elastic rubber block, which is connected to the metal fixing ring 331 by bonding, and a guide inclined surface is arranged on the elastic rubber block, which is consistent with the angle of the beveled surface of the recovery hook 2, for guiding the recovery hook 2, facilitating the extrusion of the elastic rubber block, and restoring the original state when the elastic rubber block is located in the recessed portion 22, and the elastic rubber block is clamped with the recessed portion 22.

[0063] The proximal rod body 12 is provided with an external thread 121, and the recovery hook 2 is provided with a through internal thread groove 21, and the recovery hook 2 is threadedly connected with the proximal rod body 12. The material of the external thread 121 is consistent with the proximal rod body 12, and the external thread 121 is integrally formed with the proximal rod body 12. The internal thread groove 21 of the recovery hook 2 is slightly larger in diameter than the proximal rod body 12, and the internal thread groove 21 penetrates the recovery hook 2. The internal thread is arranged on the side wall of the internal thread groove 21, and when the proximal rod body 12 and the recovery hook 2 are installed, the internal thread groove 21 is aligned with the proximal rod body 12, and the recovery hook 2 is threadedly connected with the proximal rod body 12 by rotating. The stability of the threaded connection is strong, and it is also convenient to disassemble and clean.

[0064] Regarding the disengagement operation after the stent body 11 is in place: before the stent body 11 is installed, the stent body 11 is threadedly connected with the front end of a sheath tube, specifically, the front end of the sheath tube is inserted into the internal thread groove 21 and is threadedly connected with the internal thread groove 21. After the stent body 11 is installed, the sheath tube is rotated to disengage the front end of the sheath tube from the internal thread groove 21, and the disengagement operation is completed.

[0065] More preferably, the middle part of the stent body 11 is designed as an equal-diameter structure. It can be understood that the equal-diameter structure means that the middle part of the stent body 11 is in a parallel state between the nickel-titanium wires, so that the width of the middle part of the stent body 11 is constant, and the middle part of the stent body 11 is parallel to the length direction of the blood vessel. The purpose of the equal-diameter structure is to increase the contact area between the middle part of the stent body 11 and the inner wall of the blood vessel, thereby improving the stability of the stent body 11. In another embodiment of the present application, the middle part of the stent body 11 is designed as an inclined elliptical surface structure, which increases the contact area between the stent body 11 and the inner wall of the blood vessel and improves the stability.

[0066] In the preferred embodiment of the present application, the stent part 1 further comprises a distal rod body 13 arranged at the distal end of the stent body 11, and the distal rod body 13 is annular in itself. The distal rod body 13 is connected at the head and tail to form a ring, and the distal rod body 13 is sutured together with the distal end of the stent body 11, so that the distal end of the stent body 11 has a stable opening, thereby not blocking the blood flow. The diameter of the ring formed by the distal rod body 13 is smaller than the diameter of the middle part of the stent body 11, so that the blood flow is reduced.

[0067] In the preferred embodiment of the present application, the stent body 11, the recovery hook 2 and the sleeve guide tube 32 are all provided with a developing point 5. The developing point 5 is formed by tightly winding a platinum-iridium wire, and the developing point 5 is attached by adhesion. By providing the developing point 5, the positions of the stent body 11, the recovery hook 2 and the sleeve guide tube 32 can be positioned under DSA during the operation, and the operator can make real-time adjustments, thereby reducing the difficulty of the operation.

[0068] In the preferred embodiment of the present application, the inner wall of the stent body 11 is provided with a coating film 4, the coating film 4 covers the distal end portion of the inner wall of the stent body 11, and the coating film 4 is combined with the inner wall of the stent body 11 by melting, sewing or spraying. The advantage of this design is that the coating film 4 can block the blood flow, so that the blood flow flows out at the opening at the distal end of the stent, thereby limiting the blood flow.

[0069] In the present application, the coating film 4 is a PTFE film or an ePTFE film. Both the PTFE film and the ePTFE film have excellent chemical stability and can block the blood flow, and in cooperation with the stent body 11, the blood flow can be limited. In the embodiments of the present application, the coating film 4 can cover only the distal end of the stent body 11, or can cover one-third of the distal end of the stent body 11, or can cover the entire distal end of the stent body 11.

[0070] In the preferred embodiment of the present application, when the ePTFE film is used, the coating film 4 is provided with a microporous structure, the coating film 4 is provided with a phosphocholine coating layer, and the phosphocholine coating layer covers the microporous structure. The microporous structure is a pore on the coating film 4 that does not penetrate the coating film 4. The microporous structure on the coating film 4 makes the coating film 4 more easily combined with the phosphocholine coating layer, and the phosphocholine coating layer makes the present flow-reducing device have the characteristics of biocompatibility, blood compatibility and anti-protein adsorption, thereby facilitating the subsequent removal of the device.

[0071] The present application provides a recoverable arterial blood flow-reducing device.

[0072] Embodiment 1

[0073] The present application provides a recoverable arterial blood flow-reducing device, as shown in the figure, which comprises a stent part 1, a recovery part and a pushing assembly 3.

[0074] The stent part 1 comprises a stent body 11 which is wide in the middle and gradually narrows at both ends, and the stent body 11 is formed by laser engraving from a nickel-titanium alloy material. The distal end of the stent body 11 preferably adopts a dense mesh stent, and the dense mesh requires that blood flow is not allowed to pass through. A distal end rod 13 is sewn at the distal end of the stent body 11, and the distal end rod 13 is in the form of a ring connected in a tail-to-tail manner, which is to stabilize the opening structure of the distal end of the stent body 11, and also to avoid completely blocking the blood flow.

[0075] The middle part of the stent body 11 is designed as an equal-diameter structure, and the equal-diameter part has the maximum width of the stent body 11. In the equal-diameter structure, the nickel-titanium wires in the part are parallel to each other, and the width of the part is constant. The purpose of the design is to increase the contact area between the stent body 11 and the inner wall of the blood vessel, thereby increasing the stability of the stent body 11 and enabling the stent body 11 to withstand the flow of blood without displacement.

[0076] The proximal end of the stent body 11 is provided with at least four nickel-titanium wires that are gathered to the middle part and have a funnel shape. The proximal end of the stent body 11 has a large mesh opening, which allows blood flow and has a small influence on the blood flow. The funnel-shaped proximal end design can reduce the contact area between the stent body 11 and the blood vessel, reduce endothelialization, and reduce the recovery resistance.

[0077] The middle part of the stent body 11 is designed as an equal-diameter structure, and the equal-diameter part has the maximum width of the stent body 11. In the equal-diameter structure, the nickel-titanium wires in the part are parallel to each other, and the width of the part is constant. The purpose of the design is to increase the contact area between the stent body 11 and the inner wall of the blood vessel, thereby increasing the stability of the stent body 11 and enabling the stent body 11 to withstand the flow of blood without displacement.

[0078] In the embodiment, the proximal end of the stent body 11 is welded with a proximal rod body 12. The proximal rod body 12 is preferably made of stainless steel, which has good strength and toughness and can withstand a certain tensile force and bending. In addition, the stainless steel material has certain corrosion resistance and has little influence on the human body environment.

[0079] The proximal rod body 12 is provided with a recovery hook 2. The recovery hook 2 is recessed inward on the side wall near the proximal end to form a recessed part 22. The recovery hook 2 is completely recessed in the circumferential direction, so that the recessed part 22 is an entire annular clamping groove. The recovery hook 2 and the proximal rod body 12 are connected by one of the following connection methods: threaded connection, buckle connection, snare connection, adhesion, and welding.

[0080] In a preferred embodiment of the present application, the outer circular surface of the proximal rod body 12 is provided with external threads 121, and the recovery hook 2 is provided with an internal thread groove 21 penetrating the length direction of the recovery hook 2. The proximal rod body 12 and the recovery hook 2 are connected by threaded connection.

[0081] The pushing assembly 3 includes a long sheath tube 31, which is a tube with a through channel in the middle part. The long sheath tube 31 is slidably provided with a collar catheter 32 in the middle part. The collar catheter 32 is provided with a clamping piece 33 on the inner side wall of the distal end. After the collar catheter 32 is sleeved on the recovery hook 2, the clamping piece 33 is hooked with the recovery hook 2. The collar catheter 32 is pulled out to take out the flow reducing device.

[0082] The long sheath tube 31 is made of medical grade polymer material, preferably polytetrafluoroethylene (PTFE), which has excellent chemical stability, low friction coefficient and good biocompatibility, reducing the impact on the intravascular environment. The sleeve catheter 32 is a tube with a lumen in the middle. The opening shape of the sleeve catheter 32 is not limited, as long as it is slightly larger than the proximal end of the retrieval hook 2, so that the proximal end of the retrieval hook 2 can be inserted.

[0083] Specifically, referring to Figure 6 and Figure 7 , the clamping piece 33 includes a metal fixing ring 331 connected to the inner wall of the sleeve catheter 32 by heat melting or welding. The metal fixing ring 331 is preferably made of stainless steel material to meet the strength and toughness requirements. The inner wall of the metal fixing ring 331 is welded with a metal spring 332, which extends towards the proximal end and has a 30° angle with the inner wall of the sleeve catheter 32. In other embodiments of the present application, the angle between the metal spring 332 and the inner wall of the sleeve catheter 32 is 25°, 20° or 10°. The metal spring 332 is annular and equally spaced on the metal fixing ring 331, and there are three of them.

[0084] Referring to Figure 7 , in a preferred embodiment, the metal spring 332 is a whole piece and annular.

[0085] Referring to Figure 4 , Figure 5 and Figure 6 , the release operation is as follows: before the stent body 11 is installed, a sheath tube with external threads 121 at the distal end is used, the front end of the sheath tube is inserted into the internal thread groove 21, and the sheath tube is connected with the retrieval hook 2. After the stent body 11 is installed, rotate the sheath tube to disconnect the front end of the sheath tube from the internal thread groove 21, and complete the release operation.

[0086] When the blood vessel recovers the pressure, only blood vessel puncture is needed, the long sheath tube 31 is pushed to the proximal end position of the stent body 11, the sleeve catheter 32 first contacts the retrieval hook 2, the retrieval hook 2 is inserted into the sleeve catheter 32, the metal spring 332 is deformed when extruded, enters the clamping groove, restores and abuts against the side wall of the clamping groove, and is fixed along the axial direction of the blood vessel. Then pull the sleeve catheter 32, the stent body 11 is pressed into the long sheath tube 31, and then all are recovered.

[0087] In a preferred embodiment of the present application, the stent body 11, the retrieval hook 2 and the sleeve catheter 32 are all bonded with a developing point 5, which is formed by tightly winding platinum-iridium wire. Platinum-iridium alloy has strong blocking and absorbing ability to X-ray due to its high density characteristics, which can clearly show the positions of the stent body 11, the retrieval hook 2 and the sleeve catheter 32 under DSA.

[0088] Embodiment 2

[0089] The embodiment is further illustrated the stent body 11 based on the embodiment 1.

[0090] Referring to Figure 1 and Figure 2 In the embodiment, the stent body 11 can be a non-mesh stent, and the distal end portion of the stent body 11 is provided with a film 4. Specifically, the connection mode of the film 4 is one of melting, sewing or spraying.

[0091] The film 4 is a PTFE film. The PTFE film has excellent chemical stability and can hinder blood flow, and cooperates with the stent body 11 to limit the flow of blood flow.

[0092] The film 4 is provided with a phosphocholine coating, and the setting method is one of dip coating, spraying, spin coating and chemical vapor deposition.

[0093] In another embodiment of the application, the film 4 is an ePTFE film, and the ePTFE film has a microporous structure, which is more easily combined with the phosphocholine coating, so that the device has the characteristics of biocompatibility, blood compatibility and anti-protein adsorption, facilitating the subsequent removal of the device.

[0094] Embodiment 3

[0095] The difference between the embodiment and the embodiment 1 is the clamping piece 33.

[0096] Referring to Figure 4 , Figure 5 , Figure 6 and Figure 9 The proximal end of the recovery hook 2 is retracted to the middle to form a beveled surface, and after the sleeve catheter 32 contacts the beveled surface, the beveled surface guides the sleeve catheter 32 to move along the beveled surface, thereby conveniently guiding the recovery hook 2 into the sleeve catheter 32.

[0097] The clamping piece 33 is an elastic rubber block, which is connected with the metal fixing ring 331 by adhesion, and the elastic rubber block is provided with a guide bevel, which is consistent with the angle of the beveled surface of the recovery hook 2, for guiding the recovery hook 2, facilitating the extrusion of the elastic rubber block, and restoring the original state when the elastic rubber block is located in the recessed portion 22, and the elastic rubber block is clamped with the recessed portion 22.

[0098] The above only describes the preferred embodiments of the application, and is not used to limit the application. For those skilled in the art, the application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. A recoverable arterial flow reduction device, characterized in that, The device comprises a stent part (1), a recovery part and a pushing assembly (3); The stent part (1) comprises a stent body (11) and a proximal rod (12) connected to the proximal end of the stent body (11); The recovery part comprises a recovery hook (2) connected to the proximal rod (12), and a recess (22) is arranged on the side wall of the recovery hook (2); The pushing assembly (3) comprises a long sheath tube (31) and a sleeve loop catheter (32) slidingly arranged in the long sheath tube (31), and a clamping piece (33) arranged on the sleeve loop catheter (32). After the sleeve loop catheter (32) is sleeved on the recovery hook (2), the clamping piece (33) is connected with the recess (22), and the sleeve loop catheter (32) is pulled out to take out the flow reducing device. The recess (22) is a clamping groove on the outer side wall of the proximal rod (12), which covers the circumferential direction of the side wall of the proximal rod (12) and is annular. The clamping piece (33) comprises a metal fixing ring (331) arranged on the inner wall of the sleeve loop catheter (32) and a metal spring piece (332) arranged on the inner wall of the metal fixing ring (331). One end of the metal spring piece (332) is connected to the inner wall of the metal fixing ring (331), and the other end extends towards the proximal end and forms an angle with the inner wall of the sleeve loop catheter (32). The angle between the metal spring piece (332) and the inner wall of the sleeve loop catheter (32) is ≤30°. When the metal spring piece (332) is extruded, it deforms, restores after entering the clamping groove, and abuts against the side wall of the clamping groove to realize axial fixation along the blood vessel.

2. The retrievable arterial flow-reduction device of claim 1, wherein, An outer thread (121) is arranged on the proximal rod (12), and an inner thread groove (21) is arranged on the recovery hook (2). The recovery hook (2) is threadedly connected with the proximal rod (12).

3. The retrievable arterial flow-reduction device of claim 1, wherein, The middle part of the stent body (11) is designed as an equal-diameter structure.

4. The retrievable arterial flow-reduction device of claim 3, wherein, The stent part (1) further comprises a distal rod (13) arranged at the distal end of the stent body (11), and the distal rod (13) itself forms a ring.

5. The retrievable arterial flow-reduction device of claim 1, wherein, Developing points (5) are arranged on the stent body (11), the recovery hook (2) and the sleeve loop catheter (32).

6. A recoverable arterial flow reducing device according to any one of claims 1 to 5, wherein, An inner wall of the stent body (11) is provided with a coating film (4) covering the distal end part of the inner wall of the stent body (11). The coating film (4) is combined with the inner wall of the stent body (11) by means of melting, suturing or spraying.

7. A recoverable arterial flow-reduction device according to claim 6, wherein, The coating film (4) is a PTFE film or an ePTFE film.

8. The retrievable arterial flow-reduction device of claim 7, wherein, A phosphocholine coating layer is arranged on the coating film (4).

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