CN113018646A

CN113018646A - Flow choking catheter

Info

Publication number: CN113018646A
Application number: CN201911334449.0A
Authority: CN
Inventors: 寸雨曦; 刘云云; 林恒; 刘玉梅
Original assignee: Microport Neurotech Shanghai Co Ltd
Current assignee: Microport Neurotech Shanghai Co Ltd
Priority date: 2019-12-23
Filing date: 2019-12-23
Publication date: 2021-06-25

Abstract

The invention provides a flow-resisting catheter, which comprises an inner catheter, an outer catheter and a flow-resisting element, wherein one end of the flow-resisting element is connected with the periphery of the inner catheter, and the other end of the flow-resisting element is connected with the far end of the outer catheter; the flow-obstructing element expands as the outer catheter moves in a direction toward the distal end of the inner catheter; and the flow-impeding element contracts when the outer catheter is moved in a direction away from the distal end of the inner catheter. By the configuration, the expansion of the flow resisting element can be controlled by controlling the advance and retreat of the outer catheter or the inner catheter, the configuration conversion time is short, the positioning can be repeated in the operation process, and the operation is simple, convenient and time-saving; in addition, the flow resisting element blocks the blood flow through the expansion with controllable amplitude, so that the stimulation to the cerebral vessel wall is low, and the problem of easy rupture caused by the adoption of a balloon can be avoided; in addition, when the flow resisting element contracts, the thickness of the flow resisting element is thinner, so that the inner diameter of the flow resisting element can be increased on the premise of controlling the outer diameter of the flow resisting catheter, and the flow resisting catheter is suitable for larger thrombus or instruments.

Description

Flow choking catheter

Technical Field

The invention relates to the technical field of medical instruments, in particular to a flow blocking catheter.

Background

Cerebral apoplexy, mainly caused by thrombus in cerebral vessels, is a common disease seriously threatening human health, is the third leading cause of death in the world today, and is also the disease causing the first cause of long-term disability of adults. At present, in clinical practice, thrombus is usually removed by using a therapeutic method of directly sucking thrombus by using an aspiration catheter or taking thrombus by using a stent for assisting thrombus removal, so that the recanalization of blood vessels is realized. After the suction catheter reaches the thrombus position along the blood vessel, negative pressure is applied to the near end, the thrombus is sucked into the catheter or adsorbed in the catheter opening and slowly dragged into the catheter, so that the blood vessel can obtain the blood flow power again; the stent thrombus extractor needs to cross the thrombus position, catches the thrombus by the stent meshes, retracts into the support catheter to enable the blood vessel to be communicated, and retracts into the support catheter together with the stent and the captured thrombus to enter the guide catheter after the stent retracts into the support catheter. However, in the process of embolectomy, because of the impact of proximal blood flow, thrombus often falls off and flows to a distal blood vessel, or after emboli are successfully captured, in the process of operating an aspiration catheter or an embolectomy stent to input an interventional therapy apparatus (a guide catheter or a support catheter), the broken emboli flow to the distal end of the blood vessel to form secondary occlusion, so that operation failure is caused, and the life of a patient is threatened in severe cases. For example, the myocardial necrosis rate caused by PCI percutaneous coronary intervention is as high as 16% -39%, and most of the reasons are caused by the escape of emboli from distal blood vessels during the interventional operation. In order to solve the problem caused by thrombus rupture in interventional therapy, a balloon guide catheter is usually used in the prior art to temporarily block blood flow to assist thrombus removal operation.

Generally, in the operation process, after the balloon guide catheter assists the embolectomy instrument to reach a target position (a suction catheter or a support catheter reaches the target position through an inner cavity of the balloon guide catheter), contrast solution is injected to enable the balloon to be expanded, so that the balloon can be attached to a blood vessel wall, and blood flow is temporarily blocked; after the thrombus enters the inner cavity of the suction catheter or the support catheter, the balloon guide catheter is retracted through the contraction of the balloon, and the thrombus is taken out of the human body to achieve the effect of blood flow reconstruction.

However, in the existing balloon guiding catheter products, the balloon is generally installed outside the outer catheter, and because the balloon has a certain thickness, in order to ensure that the catheter can be smoothly pushed in the blood vessel, the outer diameter of the catheter needs to be controlled to be not too large, so that the inner diameter of the catheter is too small to be adapted to a suction catheter or a support catheter with a larger lumen, and therefore, a larger thrombus cannot be treated. Meanwhile, for the balloon guide catheter, the balloon needs to be inflated with developing solution or other liquid to swell, so that the balloon can stick to the blood vessel wall to achieve the effect of blocking the blood flow, therefore, a certain time is needed for completely blocking the blood flow by using the balloon, and the contrast solution is pumped back to withdraw the balloon guide catheter, so that when the operation time is prolonged, tissue ischemia and even necrosis are caused due to overlong blood flow blocking time, and the risk that the blood vessel is damaged due to overlarge balloon filling or rupture can be brought. More importantly, in the operation process, if the balloon is inflated in an improper position, the balloon can be inflated again after the developing solution is completely discharged, a large amount of time is consumed, and the risk of balloon rupture is increased due to repeated inflation, so that secondary injury is caused to the blood vessel. In addition, the pressure caused by balloon filling is easy to stimulate the wall of cerebral vessels, thereby causing various complications in the operation process. The defects limit the auxiliary effect of the balloon in the embolectomy, and the difficulty of the embolectomy is improved, so that great risk is brought to the patient.

Disclosure of Invention

The invention aims to provide a flow-resisting catheter, which aims to solve the problems of slow flow resistance, low safety and reliability, poor repeatability, small catheter inner cavity and the like caused by adopting a saccule to resist flow in the existing guide catheter.

To solve the above technical problem, the present invention provides a flow-obstructing catheter, comprising:

an inner conduit;

the outer catheter is movably sleeved outside the inner catheter; and

one end of the flow resisting element is connected with the periphery of the inner catheter, and the other end of the flow resisting element is connected with the far end of the outer catheter; the flow-obstructing element is configured to expand when the outer catheter moves in a direction toward the distal end of the inner catheter; the flow-impeding element contracts when the outer catheter is moved in a direction away from the distal end of the inner catheter.

Optionally, in the flow blocking catheter, the flow blocking element includes a support frame, two ends of the support frame are respectively connected to the inner catheter and the outer catheter, and the support frame is configured to expand when subjected to an axial pressure and contract when subjected to an axial tension.

Optionally, in the flow-impeding conduit, the flow-impeding element further comprises a flow-impeding membrane, the flow-impeding membrane being attached to the scaffold.

Optionally, in the catheter, the distal end of the inner catheter includes an enlarged portion having a larger outer circumference than other portions of the inner catheter, and the obstructing element has one end connected to the enlarged portion and the other end connected to the distal end of the outer catheter.

Optionally, in the flow blocking catheter, the enlarged portion has a peripheral dimension that matches a peripheral dimension of the outer catheter.

Optionally, in the flow-blocking duct, the flow-blocking element comprises an equal-diameter section, the outer circumferential dimensions of which in the axial direction are the same when the flow-blocking element is expanded.

Optionally, in the flow-blocking conduit, the flow-blocking conduit further comprises a control valve to drive relative movement between the outer conduit and the outer conduit.

Optionally, in the flow blocking catheter, the control valve includes a control valve body and a control slider connected with each other, the control slider is configured to be slidable in the axial direction, the control valve body is connected with the proximal end of the inner catheter, and the control slider is connected with the proximal end of the outer catheter; or the control valve body is connected with the proximal end of the outer catheter, and the control slider is connected with the proximal end of the inner catheter.

Optionally, in the flow blocking duct, the inner duct and/or the outer duct is a single-layer tube made of a polymer material.

Optionally, in the flow blocking conduit, the inner conduit and/or the outer conduit comprises at least a two-layer structure, wherein the first and/or second layer from the inside to the outside is a polymer layer.

Optionally, in the catheter for blocking flow, the inner catheter and/or the outer catheter comprise at least two layers, and a second layer from inside to outside in the inner catheter and/or the outer catheter is one or a combination of more than two of a braided mesh structure, a coil and a cut metal tube.

Optionally, in the flow blocking conduit, the inner conduit and the outer conduit each comprise a three-layer structure.

Optionally, in the flow blocking catheter, the inner catheter comprises a first visualization ring located at a distal end of the inner catheter.

Optionally, in the flow blocking duct, the inner duct further includes a second developing ring, and the second developing ring is located on the inner duct at a position corresponding to a connection point of the flow blocking element and the inner duct.

Optionally, in the flow blocking duct, the outer duct further includes a third developing ring, and the third developing ring is located on the outer duct at a position corresponding to a connection point of the flow blocking element and the outer duct.

Optionally, in the flow-impeding catheter, the flow-impeding element comprises at least one of a mesh structure, an open loop structure, and a helical structure, the flow-impeding element being made by braiding, winding, or cutting.

Optionally, in the flow-obstructing catheter, the mesh structure is woven by 1 to 64 wires, the wires are selected from at least one of a plain wire, a developing wire and a composite wire, the plain wire is selected from at least one of a nickel-titanium alloy, a cobalt-chromium alloy, stainless steel and a polymer, the developing wire is selected from at least one of a developing metal, an alloy of a developing metal and a polymer material added with a developer, and the composite wire is formed by compounding a developing core wire and a plain wire.

In summary, the flow-blocking catheter provided by the present invention comprises an inner catheter, an outer catheter and a flow-blocking element, wherein one end of the flow-blocking element is connected to the outer circumference of the inner catheter, and the other end is connected to the distal end of the outer catheter; the flow-obstructing element expands as the outer catheter moves in a direction toward the distal end of the inner catheter; and the flow-impeding element contracts when the outer catheter is moved in a direction away from the distal end of the inner catheter. By the configuration, the expansion of the flow resisting element can be controlled by controlling the advance and retreat of the outer catheter or the inner catheter, the configuration conversion time is short, the positioning can be repeated in the operation process, and the operation is simple, convenient and time-saving; in addition, the flow resisting element blocks the blood flow through the expansion with controllable amplitude, so that the stimulation to the cerebral vessel wall is low, and the problem of easy rupture caused by the adoption of a balloon can be avoided; in addition, when the flow resisting element contracts, the thickness of the flow resisting element is thinner, so that the inner diameter of the flow resisting element can be increased on the premise of controlling the outer diameter of the flow resisting catheter, and the flow resisting catheter is suitable for larger thrombus or instruments.

Drawings

It will be appreciated by those skilled in the art that the drawings are provided for a better understanding of the invention and do not constitute any limitation to the scope of the invention. Wherein:

FIG. 1 is a schematic view of a flow blocking conduit provided in accordance with a preferred embodiment of the present invention;

FIG. 2 is a schematic illustration of a flow-blocking element provided in accordance with a preferred embodiment of the present invention in a contracted state;

FIG. 3 is a schematic illustration of a flow-impeding element provided in a preferred embodiment of the present invention in an expanded state;

FIG. 4 is a schematic illustration of a control valve provided in accordance with a preferred embodiment of the present invention;

FIG. 5 is a schematic illustration in cross-section of an inner catheter provided in accordance with a preferred embodiment of the present invention;

FIG. 6 is a schematic illustration of a cross-section of a flow blocking conduit provided in accordance with a preferred embodiment of the present invention;

FIG. 7 is a schematic view of an anti-flow catheter provided with an enlarged portion according to a preferred embodiment of the present invention;

FIG. 8 is a schematic view of a flow blocking conduit having a constant diameter section provided in accordance with a preferred embodiment of the present invention;

FIG. 9 is a schematic illustration of a braided structure of a flow-impeding element provided by a preferred embodiment of the present invention;

fig. 10a to 10g are schematic views of meshes of a support frame according to a preferred embodiment of the present invention.

In the drawings:

100-an inner catheter; 101-a first layer; 102-a second layer; 103-a third layer; 104-a binder; 110-an enlarged portion; 120-a first developer ring;

200-an outer catheter; 210-outer catheter distal end; 220-diffusion stress tube;

300-a flow-impeding element; 310-a first end; 320-a second end; 330-developing wire; 340-mesh; 350-equal diameter section;

400-a control valve; 410-a control valve body; 420-control the slide block; 430-a sliding groove; 440-a catheter hub; 500-fixing the membrane.

Detailed Description

To further clarify the objects, advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. It is to be noted that the drawings are in greatly simplified form and are not to scale, but are merely intended to facilitate and clarify the explanation of the embodiments of the present invention. Further, the structures illustrated in the drawings are often part of actual structures. In particular, the drawings may have different emphasis points and may sometimes be scaled differently.

As used in this specification, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise, the term "proximal" generally being the end near the operator and the term "distal" generally being the end near the lesion in the patient. As used in this specification, "one end" and "the other end" and "proximal end" and "distal end" generally refer to the corresponding two parts, which include not only the end points.

The core idea of the invention is to provide a flow-resisting catheter, which solves the problems of slow flow resistance, low safety and reliability, poor repeatability, small catheter inner cavity and the like caused by adopting a balloon to resist flow in the existing guide catheter. The flow-blocking catheter includes: an inner conduit, an outer conduit, and a flow-impeding element; the outer catheter is movably sleeved outside the inner catheter; one end of the flow resisting element is connected with the periphery of the inner catheter, and the other end of the flow resisting element is connected with the far end of the outer catheter; the flow-obstructing element is configured to expand when the outer catheter moves in a direction toward the distal end of the inner catheter; the flow-impeding element contracts when the outer catheter is moved in a direction away from the distal end of the inner catheter. By the configuration, the expansion of the flow resisting element can be controlled by controlling the advance and retreat of the outer catheter or the inner catheter, the configuration conversion time is short, the blood circulation of tissues is hardly influenced, the positioning can be repeated in the operation process, and the operation is simple, convenient and time-saving; in addition, the flow resisting element blocks the blood flow through the expansion with controllable amplitude, so that the stimulation to the cerebral vessel wall is low, and the problem of easy rupture caused by the adoption of a balloon can be avoided; in addition, when the flow resisting element contracts, the thickness of the flow resisting element is thinner, so that the inner diameter of the flow resisting element can be increased on the premise of controlling the outer diameter of the flow resisting catheter, and the flow resisting catheter is suitable for larger thrombus or instruments.

The following description refers to the accompanying drawings.

Referring to fig. 1 to 10g, fig. 1 is a schematic view of a flow-blocking catheter according to a preferred embodiment of the present invention, fig. 2 is a schematic view of a contracted state of a flow-blocking element according to a preferred embodiment of the present invention, fig. 3 is a schematic view of an expanded state of a flow-blocking element according to a preferred embodiment of the present invention, fig. 4 is a schematic view of a control valve according to a preferred embodiment of the present invention, fig. 5 is a schematic view of a cross section of an inner catheter according to a preferred embodiment of the present invention, fig. 6 is a schematic view of a cross section of a flow-blocking catheter according to a preferred embodiment of the present invention, fig. 7 is a schematic view of a flow-blocking catheter provided with an enlarged portion according to a preferred embodiment of the present invention, fig. 8 is a schematic view of a flow-blocking catheter provided with an equal-diameter portion according to a preferred embodiment of the present invention, fig. 9 is a schematic view of a braided structure of, fig. 10a to 10g are schematic views of meshes of a support frame according to a preferred embodiment of the present invention.

As shown in fig. 1 to 3, an embodiment of the present invention provides a flow blocking catheter, which includes: an inner catheter 100, an outer catheter 200, and a flow-impeding element 300; the outer catheter 200 is movably sleeved outside the inner catheter 100, one end (the first end 310) of the flow blocking element 300 is connected to the outer periphery of the inner catheter 100 (for example, by gluing, welding or using a fixing film), and the other end (the second end 320) is connected to the distal end (the distal end 210 of the outer catheter 200) (for example, by gluing, welding or using a fixing film); the flow-obstructing element 300 is configured such that, when the outer catheter 200 is moved in the distal direction of the inner catheter 100, the flow-obstructing element 300 expands (meaning bulges radially); when the outer catheter 200 is moved away from the distal direction of the inner catheter 100 (i.e., toward the proximal direction of the inner catheter 100), the flow-impeding element 300 contracts (i.e., radially contracts and recovers). In other embodiments, the expansion and contraction of the flow-impeding element 300 may also be controlled by movement of the inner catheter 100 relative to the outer catheter 200. In this embodiment, the first end 310 of the flow-obstructing element 300 is disposed near the distal end of the inner catheter 100 to bring the flow-obstructing location closer to the location of the embolectomy or other instrument operation, reducing the effect on the proximal vascular blood flow, and in other embodiments, the first end 310 of the flow-obstructing element 300 may be disposed in the middle or near the proximal end of the inner catheter 100.

In an exemplary embodiment, the inner catheter 100 and the outer catheter 200 are preferably circular tubes, the outer catheter 200 is sleeved outside the inner catheter 100, the difference between the inner diameter of the outer catheter 200 and the outer diameter of the inner catheter 100 can be 0.0001-0.1 inches, and the outer catheter 200 is preferably a single-layer tube made of one or more materials selected from the group consisting of polyether polyamide block copolymer (PEBA or Pebax), Polyamide (PA), and Polytetrafluoroethylene (PTFE). The inner catheter 100 comprises at least one single polymer layer of a polymer material selected from one or more of Polytetrafluoroethylene (PTFE), High Density Polyethylene (HDPE), Pebax mixed with a coefficient of friction reducing additive, and polyolefin elastomer (POE). The inner catheter 100 preferably comprises a three-layer structure, as shown in fig. 6, of a first layer 101, a second layer 102, and a third layer 103, respectively, from the inside out. Wherein, the material of the third layer 103 may be one or more of nylon elastomer (such as Pebax), nylon and Polyurethane (PU); the material of the first layer 101 may be one or more of Polytetrafluoroethylene (PTFE), High Density Polyethylene (HDPE), Pebax mixed with a friction coefficient reducing additive, and polyolefin elastomer (POE); the second layer 102 is one or a combination of two or more of a braided structure, a coil and a cut hypotube (hypotube generally refers to a medical metal tube), and the material of the second layer 102 may be stainless steel, nickel-titanium alloy, cobalt-chromium alloy or polymer filament. To improve the mechanical transmission properties and the anti-ovality and anti-buckling capabilities of the inner catheter 100 and to reduce the force required for the resistive element 300 recovery. It should be understood that the materials of the various layers of the inner catheter 100 are not limited to the above materials, and those skilled in the art can select other materials with similar properties according to the prior art. In an alternative embodiment, as shown in fig. 5, the inner catheter 100 comprises only two layers, from inside to outside, a first layer 101 and a second layer 102, wherein the first layer 101 is mainly a polymer layer and is made of one or more of Polytetrafluoroethylene (PTFE), High Density Polyethylene (HDPE), Pebax mixed with a friction-reducing additive, and polyolefin elastomer (POE), the second layer 102 is mainly a metal layer, such as one or more of a woven structure, a coil, and a cut hypotube, and the second layer 102 is made of stainless steel, nitinol, or cobalt-chromium alloy. Preferably, a layer of adhesive 104 is disposed outside the polymer layer, and the adhesive 104 penetrates the metal layer (i.e., part of the adhesive 104 penetrates the meshes of the metal layer and is adhered to the outside of the metal layer), so that the metal layer and the polymer layer are firmly embedded to improve the conductive performance and the anti-elliptical capability. Of course, in other embodiments, the outer conduit 200 is not limited to a single-layer tube, and the outer conduit 200 may also include a two-layer structure, a three-layer structure, or a more-layer structure, and the specific structural configuration thereof may refer to the inner conduit 100.

Preferably, the inner catheter 100 includes a first visualization ring 120, the first visualization ring 120 being located at the distal end of the inner catheter 100. Specifically, the first visualization ring 120 may be disposed at the distal end of the second layer 102 of the inner catheter 100. More preferably, the inner catheter 100 further comprises a second visualization ring (not shown) located at a position of the inner catheter 100 corresponding to a connection point of the flow blocking element 300 and the inner catheter 100. Further, the outer catheter 200 further includes a third developing ring (not shown) located on the outer catheter 200 at a position corresponding to a connection point of the flow blocking element 300 and the outer catheter 200. Alternatively, the first developing ring 120, the second developing ring and the third developing ring may be made of, but not limited to, platinum, iridium, tantalum, noble metal alloy, etc., or may be made of a polymer material containing a developer. The three visualization rings are provided to facilitate the operator positioning the catheter 100 during the procedure. It should be understood that the first visualization ring 120 is located at the distal end of the inner catheter 100, and the first visualization ring 120 is not limited to being located at the distal end of the inner catheter 100, but may be located in an area near the distal end of the inner catheter 100. Further, the above examples merely exemplify the arrangement positions of the developing rings, and do not limit that the three developing rings are necessarily arranged at the same time, and any one or any two of the developing rings may be selectively arranged by those skilled in the art according to the actual situation.

Preferably, the flow blocking element 300 includes a support frame attached to both ends of the support frame connected to the inner catheter 100 and the outer catheter 200, respectively, and a flow blocking film configured to expand (i.e., expand in a radial direction) when subjected to an axial pressure and contract (i.e., contract in a radial direction) when subjected to an axial tension. In one example, the scaffold is a tubular body that is capable of being switched between a retracted state and an expanded state, it being understood that the scaffold is not limited to being switched between the retracted state and the expanded state, and in some cases, may be in an intermediate state between the retracted state and the expanded state (i.e., a semi-expanded state or a partially expanded state). The material of the support frame can be nickel-titanium alloy, 304 stainless steel, platinum-tungsten alloy, platinum-iridium alloy, cobalt-chromium alloy or developed metal, and the structure of the support frame can be obtained by winding, cutting or weaving. In this embodiment, the supporting frame comprises a plurality of mesh holes 340, and as shown in fig. 10a to 10g, the mesh holes 340 may be diamond-shaped (fig. 10a), square-shaped (fig. 10b), rectangular-shaped (fig. 10c), parallelogram-shaped (fig. 10d), polygonal-shaped (not shown), circular-shaped (fig. 10e), oval-shaped (fig. 10f), irregular-shaped (fig. 10g), and the like, and preferably diamond-shaped (fig. 10 a). The flow-blocking film can be attached to the inner surface or the outer surface of the support frame, and is preferably a polymer film, and the material of the flow-blocking film can be Polyurethane (PU), Polyethylene (PE), Expanded Polytetrafluoroethylene (EPTFE) or the like. It is to be understood that the material of the supporting frame and the flow-resisting film is not limited to the above materials, and those skilled in the art can select other materials with similar performance according to the prior art. As shown in fig. 9, in some embodiments, the supporting frame may be a mesh structure formed by weaving 1 to 64 wires, the wires include common wires and/or developing wires, and the common wires may be selected from one or more of nickel-titanium alloy, cobalt-nickel alloy, platinum-iridium alloy, platinum, gold, tungsten, and the like; the developing wire can be made of developing metals such as platinum, iridium, gold, tungsten and the like or alloys thereof, or polymer wires with developer added can be selected. The developing wire 330 improves the developing performance of the flow blocking element 300 and improves the trackability of the flow blocking element 300 in use. In other embodiments, the scaffold may also be an open-loop structure or a helical structure, or the scaffold may be composed of several of a lattice structure, an open-loop structure and a helical structure.

Referring to fig. 2 and 3, the outer catheter 200 may control the expansion of the flow-blocking element 300 when moving along the axial direction of the inner catheter 100 (the expansion of the flow-blocking element 300 may be understood to be the same as the expansion of the scaffold). Specifically, as shown in fig. 2, for convenience of description, a connection point of the first end 310 of the flow blocking element 300 and the inner catheter 100 is referred to as a first connection point, a connection point of the second end 320 of the flow blocking element 300 and the outer catheter 200 is referred to as a second connection point, and in an initial default state of the flow blocking catheter, a distance between the first connection point and the second connection point along the axial direction of the inner catheter 100 is the largest, and at this time, the flow blocking element 300 is in a fully retracted state, and the largest outer diameter of the flow blocking element is equivalent to the outer diameter of the outer catheter. On the basis of fig. 2, the outer catheter 200 is pushed distally such that the axial distance between the first connection point and the second connection point is reduced, and the flow-obstructing element 300 expands radially outwards, as shown in fig. 3, which illustrates the flow-obstructing element 300 in a fully expanded state. When the flow-obstructing element 300 expands outward to fit the inner diameter of the vessel wall, the flow-obstructing element 300 is attached to the vessel wall, and the blood flow is blocked because a flow-obstructing membrane is attached to the support frame of the flow-obstructing element 300. It is to be understood that the expansion of the obstructing element 300 is now adapted to the vessel wall and not necessarily in a fully expanded state (i.e. possibly in a semi-expanded state or in a partially expanded state), the obstructing element 300 preferably has a compliance which is adapted to the shape of the vessel wall in the expanded state (including the fully expanded state, the semi-expanded state or the partially expanded state). So configured, some relatively weak vessel walls may be accommodated, which may reduce the pressure on the vessel wall caused by the expansion of the resistive element 300. Therefore, the flow blocking element 300 can reduce the stimulation to the cerebral vessel wall, reduce the occurrence of various complications such as vasospasm and the like in the operation process, and simultaneously thoroughly avoid the risk of secondary damage to the vessel caused by the rupture of the balloon or the balloon bonding section.

Further, after the blood flow is blocked, suction or thrombus retraction can be directly performed through the lumen of the inner catheter 100 (the lumen of the inner catheter 100 of the flow blocking catheter can also be passed through a suction catheter or a support catheter, suction of thrombus can be performed through the suction catheter, or thrombus removal can be performed through a thrombus removal stent in the support catheter). As shown in fig. 2, since the thickness of the flow blocking element 300 is smaller when in the retracted state, the ratio of the inner cavity of the inner catheter 100 in the cross section of the whole flow blocking catheter is much larger than that of the existing balloon flow blocking catheter, so that the flow blocking catheter with the same outer diameter can be adapted to medical devices such as a suction catheter, a support catheter or a stent with a larger lumen, and is suitable for treating larger thrombus, and simultaneously, the outer diameter of the whole flow blocking catheter is limited to smoothly enter a tortuous distal end blood vessel and form a smaller wound for a patient.

Further, when it is desired to change the flow blocking position to reposition or remove the flow blocking catheter, the outer catheter 200 is operable to move proximally relative to the inner catheter 100 (i.e., to withdraw the outer catheter 200) to a maximum distance between the first and second connection points along the axial direction of the inner catheter 100. On the basis of fig. 3, when the outer catheter 200 is withdrawn proximally, the state of the flow-blocking element 300 is reversible, i.e. the flow-blocking element 300 can be retracted until the state shown in fig. 2 is reached. The repeatable contractibility of the flow-impeding element 300 facilitates the re-delivery positioning of the flow-impeding conduit. Therefore, the flow blocking catheter provided by the embodiment can conveniently realize repeated operation and accurate positioning, and can also conveniently withdraw the blood vessel after thrombus removal.

As shown in fig. 4, the flow blocking conduit further comprises a control valve 400, the control valve 400 being configured to drive the outer conduit 200 to move relative to the inner conduit 100. In one embodiment, the control valve 400 includes a control valve body 410 and a control slider 420, wherein the control valve body 410 is provided with a sliding groove 430 along an axial direction, and the control slider 420 is matched with the sliding groove 430 and can slide along the direction of the sliding groove 430. Further, one end of the control valve body 410 has a catheter insertion opening 440, and the proximal end of the inner catheter 100 is inserted into the control valve 400 through the catheter insertion opening 440 and fixedly connected to the control valve body 410, while the proximal end of the outer catheter 200 is connected to the control slider 420, for example, by gluing or snapping. With such a configuration, the sliding of the slider 420 is controlled to control the movement (e.g., withdrawing or pushing) of the outer catheter 200 relative to the inner catheter 100, and the control valve 400 controls the expansion or retraction state of the flow blocking element 300, so as to simplify the operation, save the operation time, and conveniently realize the repetitive operation. Optionally, the proximal end of the outer catheter 200 includes a diffusion stressed tube 220, and the diffusion stressed tube 220 may be flared towards the proximal end, i.e. the distal end of the diffusion stressed tube 220 has the same diameter as the outer catheter 200, while the proximal end of the diffusion stressed tube 220 has a larger diameter than the outer catheter 200. With this configuration, the diameter of the portion of the outer guide pipe 200 for connection with the control slider 420 is increased, and the flared diffusive stress pipe 220 disperses the driving force of the control slider 420 to the outer guide pipe 200, thereby improving the reliability of control of the outer guide pipe 200 by the control slider 420. In other embodiments, the outer conduit may be connected to the control valve body 410, the inner conduit 100 may be connected to the control slider 420, or other direct or indirect connection methods may be used, and the present invention is not particularly limited.

Referring to fig. 7, in a preferred embodiment, the outer circumference of the distal end of the inner catheter 100 includes an enlarged portion 110, the outer circumference of the enlarged portion 110 is larger than the outer circumference of the other portion of the inner catheter 100, one end (a first end 310) of the obstructing member 300 is connected to the enlarged portion 110, and the other end (a second end 320) is connected to the distal end 210 of the outer catheter. Here, the "outer circumferential dimension" refers to a circumference of a cross section of the inner catheter 100 or the outer catheter 200, for example, when the inner catheter 100 and the outer catheter 200 are circular tubes, the "outer circumferential dimension" is an outer diameter of the inner catheter 100 or the outer catheter 200. Preferably, the enlarged portion 110 matches the outer circumference of the outer catheter 200, the enlarged portion 110 is located distally of the distal end of the outer catheter 200, and in an exemplary embodiment, the main body portion of the inner catheter 100 has an outer diameter of between 0.070-0.113 inches and a length of between 70-100 mm; and the enlarged portion 110 has an outer diameter of between 0.079 and 0.122 inches and a length of between 1 and 50 mm. Preferably, the inner diameter of the outer catheter 200 is slightly larger than the outer diameter of the main body portion of the inner catheter 100, the outer catheter 200 is mainly sleeved outside the main body portion of the inner catheter 100, and the outer diameter of the outer catheter 200 may be the same as the outer diameter of the enlarged portion 110. Preferably, the axial distance between the distal end 210 of the outer catheter and the enlarged portion 110 is between 5-50mm, and the first connection point between the first end 310 of the flow-obstructing element 300 and the enlarged portion 110 is close to the connection point of the enlarged portion 110 and the main body portion of the inner catheter 100; a second connection point between the second end 320 of the flow-impeding element 300 and the outer catheter 200 is near the outer catheter distal end 210. The enlarged portion 110 of the inner catheter 100 may be configured to maintain a consistent outer diameter of the entire catheter, preventing the obstructing member 300 from being damaged when the catheter passes through a tortuous blood vessel during transport of the catheter in the blood vessel. Furthermore, the radial distances of the first connection point and the second connection point with respect to the axial direction of the inner catheter 100 are substantially equal, which facilitates the retention of concentricity of the flow blocking element 300 without eccentricity when expanding, increases the uniformity of adherence of the flow blocking element 300, and thus reduces the risk of leakage.

Referring to fig. 8, in a preferred embodiment, the flow blocking element 300 includes a constant diameter section 350, and when the flow blocking element 300 is expanded, the constant diameter section 350 has the same outer circumferential dimension in the axial direction (i.e., is cylindrical). Optionally, the constant diameter section 350 of the flow blocking element 300 is shaped into a constant diameter tubular state in an expansion state during thermoforming, and thus, when the flow blocking element 300 expands due to axial pressure, the constant diameter section 350 expands synchronously along the axial direction, and the shape can better fit the blood vessel wall and has a better blood flow blocking effect. It should be appreciated that in some embodiments, when the flow blocking element 300 expands, the constant diameter section 350 is not limited to synchronous expansion, but both ends expand one after another, and the outer surface of the constant diameter section 350 is a slope (i.e., the overall shape is conical), and the constant diameter section 350 does not reach the same shape (i.e., cylindrical) of the outer circumference dimension along the axial direction until the flow blocking element 300 is in the fully expanded state or the state of being adapted to the inner diameter of the blood vessel wall, which is not limited by the present invention.

The above description is only for the purpose of describing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention, and any variations and modifications made by those skilled in the art based on the above disclosure are within the scope of the appended claims.

Claims

1. A flow-blocking catheter, comprising:

an inner conduit;

the outer catheter is movably sleeved outside the inner catheter; and

2. The catheter of claim 1, wherein the flow-blocking element includes a cage coupled at opposite ends to the inner catheter and the outer catheter, respectively, the cage configured to expand when subjected to axial compression forces and contract when subjected to axial tension forces.

3. The choke catheter of claim 2, wherein the choke element further includes a choke membrane, the choke membrane being attached to the support scaffold.

4. The catheter of claim 1, wherein the distal end of the inner catheter includes an enlarged portion having a larger outer circumferential dimension than other portions of the inner catheter, the obstructing member having one end connected to the enlarged portion and another end connected to the distal end of the outer catheter.

5. The catheter of claim 4, wherein the enlarged portion has a peripheral dimension that matches a peripheral dimension of the outer catheter.

6. The choke catheter of claim 1, wherein the choke element includes an equal diameter section that has the same outer circumferential dimension in an axial direction when the choke element is expanded.

7. The flow-blocking conduit of claim 1, further comprising a control valve to drive relative movement between the outer conduit and the outer conduit.

8. The catheter of claim 7, wherein the control valve includes a control valve body and a control slider connected, the control slider configured to be axially slidable, the control valve body connected to the proximal end of the inner catheter, the control slider connected to the proximal end of the outer catheter; or the control valve body is connected with the proximal end of the outer catheter, and the control slider is connected with the proximal end of the inner catheter.

9. The flow-impeding conduit of claim 1, wherein the inner conduit and/or the outer conduit is a single-layer tube made of a polymeric material.

10. The flow-impeding conduit of claim 1, wherein the inner conduit and/or the outer conduit comprises at least a two-layer structure, wherein a first layer and/or a second layer from inside to outside is a polymer layer.

11. The catheter of claim 1, wherein the inner catheter and/or the outer catheter comprise at least two layers, and wherein a second layer from the inside out of the inner catheter and/or the outer catheter is one or a combination of more than two of a braided mesh structure, a coil, and a cut metal tube.

12. The flow-impeding conduit of claim 10 or 11, wherein the inner conduit and the outer conduit each comprise a three-layer structure.

13. The flow-impeding catheter of claim 1, wherein the inner catheter comprises a first visualization ring located at a distal end of the inner catheter.

14. The choke conduit of claim 13, further comprising a second developer ring positioned on the inner conduit at a location corresponding to a connection point of the choke element to the inner conduit.

15. The flow-impeding conduit of claim 13 or 14, wherein the outer conduit further comprises a third visualization ring located on the outer conduit at a position corresponding to a connection point of the flow-impeding element with the outer conduit.

16. The choke catheter of claim 1, wherein the choke element includes at least one of a mesh structure, an open loop structure, and a helical structure, the choke element being fabricated by braiding, winding, or cutting.

17. The catheter of claim 16, wherein the lattice structure is woven from 1-64 filaments, the filaments are selected from at least one of plain filaments, developing filaments, and composite filaments, the plain filaments are selected from at least one of nitinol, cobalt-chromium alloy, stainless steel, and polymer, the developing filaments are selected from at least one of developing metal, alloy of developing metal, and polymer material with developer added, and the composite filaments are formed by compounding developing core filaments and plain filaments.