WO2023087980A1

WO2023087980A1 - Device for removing substance from blood vessel

Info

Publication number: WO2023087980A1
Application number: PCT/CN2022/124597
Authority: WO
Inventors: Yusheng Wu; Lixia GUO; YuanLi DONG
Original assignee: Orbusneich Medical (Shenzhen) Company Limited
Priority date: 2021-11-18
Filing date: 2022-10-11
Publication date: 2023-05-25

Abstract

A device (300) for removing a substance from a blood vessel, the device (300) including: a foldable frame (340) and a polymeric membrane (360) having holes. The frame (340) is provided with a proximal end and a distal end and includes edge members (620) arranged near the proximal end and the distal end of the frame respectively, and a mesh (640) extending between the edge members (620). When an action of an external force is removed, the frame (340) can expand into a cylinder shape under an action of elasticity of a material of the frame (340), and the frame (340) is provided with oblique openings (342, 346) at both the proximal end and the distal end. The polymeric membrane (360) is engaged with the distal end of the frame (340), and when the frame (340) expands into the cylinder shape, the polymeric membrane (360) spans the oblique opening (346) of the frame at the distal end.

Description

DEVICE FOR REMOVING SUBSTANCE FROM BLOOD VESSEL

Technical Field

The present disclosure relates to a medical instrument, and particularly to a device for removing a substance such as a blood clot from a blood vessel.

Background Art

Ischemic stroke is a nerve tissue damage caused by ischemic necrosis of local brain tissue as a result of occlusion of cerebral arteries. This occlusion will prevent blood from flowing to limbs or organs, thereby causing acute symptoms such as muscle weakness on one side of the body, paralysis, speech disorders, thought disorders and vision disorders, etc., and permanent complications such as in-vivo tissue cell death are likely to occur. Thus, ischemic stroke is a significant cause of long-term disability and is also a common cause of death.

Prior to the emergence of an interventional thrombectomy, systemic intravenous thrombolysis is the only evidence-based therapy for acute patients. However, high doses of thrombolytic agents may render complications such as intracranial or systemic hemorrhage. In recent years, removing an obstruction by a mechanical thrombectomy device has become a procedure widely accepted by patients with cerebral stroke. Using a catheter-based thrombectomy device, a catheter enters a blood vessel through an incision and is then pushed to an occlusion in the blood vessel, thereby feeding a thrombectomy device to the position of a thrombus. After capturing and wrapping blood clots, the thrombectomy device is withdrawn with the blood clots by means of the catheter. In this way, the blood clots associated with ischemic stroke are removed, so as to be prevented from forming permanent occlusion in the blood vessel.

When an existing thrombectomy device is withdrawn after capturing a thrombus, vascular occlusion may occur again because the captured thrombus is possible to fall off, or the captured large thrombus is possible to be split into small thrombi which will escape. Therefore, a desired thrombectomy device should be able to firmly trap blood clots, such that the blood clots are not likely to fall off and escape once trapped.

Accordingly, it is necessary to provide a device for removing a substance from a blood vessel, which has improved performance in treating vascular occlusion, and can overcome or partially overcome the above drawbacks and provide an alternative to existing products.

Summary of the Invention

The features and advantages of the present disclosure will be illustrated in the following description, part of which will be apparent according to the description, or may be learned by practicing the principles disclosed herein. The features and advantages of the present disclosure may be achieved and obtained by virtue of the means and combinations particularly mentioned in the description.

A first aspect of the present disclosure provides a device for removing a substance from a blood vessel. The device includes: a foldable frame, wherein the frame is provided with a proximal end and a distal end and includes edge members arranged near the proximal end and the distal end of the frame respectively, and a mesh extending between the edge members, when an action of an external force is removed, the frame is capable of expanding into a cylinder shape under an action of elasticity of a material of the frame, and the frame is provided with oblique openings at both the proximal end and the distal end; and a polymeric membrane with holes, wherein the polymeric membrane is engaged with the distal end of the frame, and when the frame expands into the cylinder shape, the polymeric membrane spans the oblique opening of the frame at the distal end.

In the device, the polymeric membrane may be engaged with the edge member without covering the mesh.

When the frame of the device expands, a middle region may be formed between the oblique openings at the proximal end and the distal end, and the middle region has a longitudinal size longer than a longitudinal length of the oblique openings.

When the frame of the device expands, a longitudinal axis of the cylinder shape extends from the proximal end to the distal end, and in each plane perpendicular to the longitudinal axis, there is no more than two junctions of elements of the mesh.

The mesh may include a plurality of parallelogram units, the parallelogram unit including four elongated elements connected at the junctions, wherein the parallelogram units may have different areas.

The device may include two edge members converging toward the proximal end of the frame, wherein there is at least one quadrilateral unit at an interface between the two edge members and the mesh.

Optionally, the device may include three edge members converging toward the proximal end of the frame, wherein there is at least one triangular unit at an interface between the three edge members and the mesh.

Optionally, the device may include three edge members converging toward the proximal end of the frame, wherein there is at least one quadrilateral unit at an interface between the three edge members and the mesh.

The device may further include a push wire, wherein the edge members arranged at the proximal end of the frame converge at one end of the push wire.

The push wire may include a positioning member configured to match a corresponding positioning structure in a push rod.

The device may further include a developing member positioned between the positioning member and the proximal end of the frame.

Optionally, the holes of the polymeric membrane are uniformly distributed on the polymeric membrane. The hole has an approximately round or ellipse shape having a diameter/major axis of 0.1 mm -2.5 mm, and a distance between the holes is 0.5 mm -5 mm.The polymeric membrane’s material may be selected from E-polytetrafluoroethylene, polyethylene or polyethylene terephthalate.

Optionally, the edge members of the device include a left edge member and a right edge member, wherein the left edge member and the right edge member are joined with each other at the middle region of the frame, so as to form a closed middle region of the frame.

Optionally, the edge members of the device include a left edge member and a right edge member, and the left edge member and the right edge member are separated from each other at the middle region of the frame, so as to form an open middle region of the frame.

The frame may have a diameter of 3 mm -7 mm and a length of 15 mm -70 mm in an expanding state. The frame is sized such that in a folded state, the frame can be accommodated within a catheter having an inner diameter of 0.0165 inch -0.027 inch. The parallelogram unit of the mesh of the frame has an area of 5 mm ² -30 mm ².

Brief Description of the Drawings

In order to describe the way in which the above and other advantages and features of the present disclosure can be obtained, a more specific description will be made by reference to specific embodiments illustrated in the accompanying drawings. It should be understood that these accompanying drawings only depict exemplary embodiments of the present disclosure and therefore are not to be considered limiting of the scope thereof, and the principle of the present disclosure is described and explained with specific examples and details by means of the accompanying drawings. In the accompanying drawings:

FIG. 1 is an exemplary perspective view of a system for removing an obstruction from a blood vessel.

FIG. 2 is an exemplary perspective view of a thrombectomy device according to an embodiment of the present disclosure.

FIG. 3a is an exemplary top view of a frame of a thrombectomy device according to an embodiment of the present disclosure.

FIG. 3b is an exemplary side view of a frame of a thrombectomy device according to an embodiment of the present disclosure.

FIG. 4a is a schematic diagram of a proximal-end portion of a thrombectomy device according to an embodiment of the present disclosure.

FIG. 4b is a schematic diagram of a proximal end of a thrombectomy device in FIG. 3a connected to a push rod.

FIG. 5 is a schematic diagram of a distal-end portion of a thrombectomy device according to an embodiment of the present disclosure.

FIGS. 6a-d are plane views of frames before assembly according to embodiments of the present disclosure.

FIG. 7a is an exemplary perspective view of a thrombectomy device having an open middle region according to an embodiment of the present disclosure.

FIG. 7b is an exemplary perspective view of a thrombectomy device having a closed middle region according to an embodiment of the present disclosure.

FIGS. 8a-h are an exemplary thrombectomy method implemented by means of a thrombectomy device in the present disclosure.

Detailed Description of Embodiments

A distal end of an existing thrombectomy device is provided with an opening in most cases, and in a withdrawing process after a thrombus is captured, the captured large thrombus may be split into small thrombi which leak out from the opening of the thrombectomy device at the distal end, and captured thrombus fragments may also escape and leak out from the opening at the distal end, thereby causing a risk of secondary occlusion of a blood vessel.

The present disclosure provides a device for removing a obstruction from a blood vessel. The device includes a thrombectomy stent and a polymeric membrane arranged at a distal end of the thrombectomy stent. The device can not only capture a thrombus, but also prevent the thrombus captured in a thrombectomy process from returning to a blood vessel, thereby reducing a probability of secondary occlusion, facilitating the procedure and improving safety of the procedure.

In addition, according to the device provided in the present disclosure, through a specific mesh design, enough strength can be provided for a stent to support expansion of the stent in the blood vessel; and enough softness and flexibility are further provided such that the thrombectomy device can adapt to a natural shape of the blood vessel, deliverability of the thrombectomy device is improved and time of the procedure is shortened.

Various embodiments of the present disclosure will be discussed in detail below. While specific implementations are discussed, it should be understood that it is intended for illustrative purposes only. Those skilled in the relevant art will recognize that other assemblies and configurations may be used without departing from the spirit and scope of the present disclosure. In the embodiments, a system/device for removing an obstruction from a blood vessel is a thrombectomy system/device for removing a blood clot from a blood vessel, but it can be understood that the device may further be used for removing other substances/obstructions from the blood vessel.

In the following description, the same reference numerals denote the same components. “Proximal” refers to an orientation of a catheter close to an operator when in use, and “distal” refers to an orientation of the catheter away from the operator when in use.

As shown in FIG. 1, the system for removing an obstruction from a blood vessel (also referred to as a thrombectomy system) includes a push rod 100 and a thrombectomy device 300 connected to a distal end of the push rod 100. The thrombectomy system 100 further includes a protective sleeve 200 for storing, when the thrombectomy system 100 is not in use, the thrombectomy device 100 (what is shown in FIG. 1 is a state of the thrombectomy device 100 extending from the protective sleeve 200) , and assisting, when the thrombectomy system 100 is in use, the thrombectomy device 100 in a stored state to enter a microcatheter (not shown) . After the thrombectomy device 100 enters the microcatheter, the protective sleeve 200 is withdrawn, and the thrombectomy device 100 is pushed to a target position by means of the push rod 100.

FIG. 2 is an exemplary perspective view of a thrombectomy device 300 according to an embodiment of the present disclosure.

As shown in FIG. 2, the thrombectomy device 300 includes a frame 340. The frame 340 is provided with a proximal end and a distal end, the frame 340 longitudinally extends between the proximal end and the distal end, and is provided with oblique openings facing one side of a longitudinal axis at the two ends. The distal end of the frame 340 is engaged with a polymeric membrane 360, and the polymeric membrane 360 spans and covers the opening of the frame 340 at the distal end. The proximal end of the frame 340 is connected to a push wire 320 and then to a push rod 100.

The frame 340 is made of a material having elasticity, and is preformed into an approximately cylinder shape through a heat treatment or other processes, and the frame in the cylinder shape can be folded under the action of an external force such that the frame can be contracted and then stored in the protective sleeve/microcatheter. After the external force is removed, the frame may expand and return to the preformed shape under the action of elasticity of the material of the frame.

In an exemplary example, the frame has an outer diameter of 0.0165 inch -0.027 inch when in a folded state, or the frame may be sized such that it can be accommodated within a microcatheter having an inner diameter of 0.0165 inch -0.027 inch.

In an exemplary example, the frame may have a diameter of 3 mm -7 mm and a length of 15 mm -70 mm in an expanding state.

The distal end of the thrombectomy device 300 in the embodiment is covered by the polymeric membrane 360. Compared with a thrombectomy device with an opening at a distal end, the device has the effects that when fragments of a thrombus captured by the frame fall off, these fragments can be further netted by the polymeric membrane and will not flow back into the blood vessel to cause secondary occlusion. In addition, the polymeric membrane has a softness better than that of the material of the frame, and is therefore more easily stored and deployed. Therefore, the thrombectomy device, of which the opening of the frame at the distal end is covered by the polymeric membrane, has a better flexibility than a thrombectomy device, of which the distal end of the frame is closed.

FIGS. 3a and 3b show a top view and a side view of a frame in an expanding state. As shown in FIGS. 3a and 3b, the frame 340 longitudinally extends between the proximal end and the distal end, and is provided with openings at the two ends, and a middle region 344 positioned between the opening 342 at the proximal end and the opening 346 at the distal end is a mesh.

When the frame 340 expands, the middle region 344 is formed between the oblique openings at the proximal end and the distal end, and the middle region 344 has a longitudinal size L2 longer than a longitudinal length L1 of the oblique opening 342 at the proximal end or a longitudinal length L3 of the oblique opening 346 at the distal end. The middle region is a main working region of the thrombectomy device and is used for capturing a large thrombus during a procedure.

In an exemplary embodiment, the openings at the proximal end and the distal end of the frame 340 are oblique openings or approximately elliptical openings facing one side of a longitudinal axis such that a thrombus can be conveniently captured and the thrombectomy device can conveniently enter and exist from a catheter. In an exemplary embodiment, the opening regions of the frame 340 at the proximal end and the distal end are approximately symmetrical with respect to the middle region, and the opening at the distal end is engaged with the polymeric membrane having holes.

In an exemplary embodiment, the frame 340 is formed by cutting out a mesh from a material in the shape of a pipe or a sheet. For example, a surface of a pipe is irradiated by a focused high-power-density laser beam, so as to enable an irradiated material to be rapidly molten, vaporized, ablated or to reach an ignition point; meanwhile, a molten substance is blown away by a high-speed airflow coaxial with the beam, so as to remove materials in the mesh on the pipe; and then shaping is carried out through heat treatment. Alternatively, a surface of a sheet is irradiated by a focused high-power-density laser beam, so as to enable the irradiated sheet material to be rapidly molten, vaporized, ablated or to reach an ignition point; meanwhile, a molten substance is blown away by a high-speed airflow coaxial with the beam, so as to cut off materials in the mesh on the sheet; and then shaping is carried out through heat treatment after winding is carried out. Finally, the mesh shaped through heat treatment is polished by an acid fluid according to a galvanic cell principle to remove materials, so as to achieve a required size and satisfy surface requirements.

In an exemplary example, a material of the frame is a memory metal such as a nickel titanium alloy or the like. Before use, the frame is subjected to heat treatment to make same have a predetermined shape. During a procedure, after being released from a microcatheter, the frame returns to the predetermined shape when sensing the temperature of blood.

FIG. 4a shows a schematic diagram of a push wire 320 of a thrombectomy device. FIG. 4b shows a schematic diagram of a push wire 320 connected to a push rod 100.

As shown in FIGS. 4a and 4b, a distal-end section of a push rod 100 includes a fixing ring 120 provided with an opening 122 on one side, and a proximal end and a middle portion of the push wire 320 include positioning

members

322, 324 radially protruding outwardly, and a distance between the two positioning members is corresponding to a longitudinal length of the fixing ring 120. The push wire 320 may enter an interior of the fixing ring 120 through the opening 122 of the fixing ring 120 and match the fixing ring 120, and the

positioning members

322, 324 of the push wire 320 are retained at two ends of the fixing ring 120, such that the push wire 320 is positioned at a predetermined position of the push rod 100. By means of such a structure, the push wire may be accurately and firmly positioned.

In an exemplary embodiment, the fixing ring 120 may serve as an independent structure fixedly connected to the distal end of the push rod, or the fixing ring 120 may be integrally formed with the push rod 100. For example, the distal-end section of the push rod 100 is forged or pressed into a planar structure, and is then shaped into a cylinder-like structure 120 through crimping; two positioning members are cut on the push wire 320 through laser forming; after the cylinder-like structure 120 of the push rod 100 and the positioning structure of the push wire 320 are assembled, a matching position between the push rod and the push wire is pre-tightened through clamping or forging; and spot welding may be additionally used at the two ends separately for fixation such that the thrombectomy device can be rapidly and firmly mounted on the push rod.

In an exemplary embodiment, the push wire 320 may further include a developing member for displaying a position of the push wire 320 under X-ray irradiation during a procedure. For example, the developing member is a developing ring arranged between the positioning members and the proximal end of the frame.

FIG. 5 is a schematic diagram of a distal-end portion of a thrombectomy device according to an embodiment of the present disclosure. As shown in FIG. 5, the distal end of the frame 340 of the thrombectomy device is engaged with the polymeric membrane 360 having holes, and when the frame 340 expands into a cylinder shape, the polymeric membrane 360 spans the oblique opening of the frame at the distal end. A surface of the polymeric membrane 360 is provided with holes 362, blood may flow through the holes without being blocked. Moreover, the holes have proper sizes such that small pieces of thrombus or thrombus fragments are not likely to leak out. Through the design of the polymeric membrane 360, there is no large leakage port at the distal end of the thrombectomy device 300.

The polymeric membrane 360 has a certain elasticity and softness, and when the frame 340 is stored in a protective sleeve/microcatheter, the polymeric membrane 360 will be curled into a corresponding shape along with contraction of the frame 340 and restriction of the catheter. When the catheter moves backward and no longer restricts the frame 340, the frame 340 may expand due to the elasticity thereof, so as to drive the polymeric membrane 360 to be opened together.

In an exemplary embodiment, the polymeric membrane covers the entire region of the opening of the frame at the distal end, and may be engaged with the distal end of the frame by about 1 mm -3 mm, so as to guarantee that the polymeric membrane can be tightly fixed to the frame. Since the thrombectomy device in the present disclosure relies on the mesh at the middle region of the frame to capture a thrombus, the polymeric membrane does not cover the middle region of the frame. Therefore, if the middle region is covered by a membrane, the thrombus may not be firmly captured.

In an exemplary embodiment, the polymeric membrane is made of a material having a softness better than that of the frame. For example, the polymeric membrane’s material may be selected from E-polytetrafluoroethylene (E-PTFE) , polyethylene or polyethylene terephthalate (PET) .

In an exemplary embodiment, the polymeric membrane may be engaged with the distal end of the frame through sewing, hot melting or adhesion.

In an exemplary embodiment, the holes are uniformly distributed on the polymeric membrane. The hole has an approximately round or ellipse shape having a diameter/major axis size of 0.1 mm -2.5 mm, and a distance between the holes is 0.5 mm -5 mm.

FIGS. 6a-d are expanded plane views of

frames

600a, 600b, 600c, 600d (or collectively referred to as frame 600) according to embodiments of the present disclosure, that is, schematic diagrams of frames in cylinder shapes shown in FIGS. 3a and 3b cut from top and then laid.

As shown in FIGS. 6a-d, the frames 600a-d each include edge members 620 and a mesh 640 formed by a plurality of parallelogram units. There are a plurality of edge members 620 positioned at the distal end and the proximal end of the frame respectively, and the mesh 640 extends between the edge members 620.

Each parallelogram unit in the mesh 640 includes four surrounding elongated elements, and the elements of different parallelogram units are connected at junctions. The edge members 620 at the proximal end converge at a junction 660 at the distal end of the push wire 320, and the edge members 620 at the distal end converge at a junction 680 at the distal end of the frame, such that the thrombectomy device formed in this way is provided with longitudinal openings tapering toward the junctions at the distal end and the proximal end of the frame respectively.

The strength of the proximal end and the distal end of the frame 600 is related to the number of edge members 620. The more the edge members, the higher the strength of the two ends of the frame, the lower softness, and the larger a profile formed after folding. Conversely, the less the edge members, the lower the strength of the proximal end of the frame, the higher softness, and the smaller a profile formed after folding. In addition, a geometry formed by the edge members at the two ends of the frame will also affect the strength of the two ends of the frame. For example, a triangle has a strength lower than that of a quadrangle.

The strength/softness of the middle region of the frame 600 is related to the distribution of the junctions of the elements in the mesh. The more junctions in each plane perpendicular to a longitudinal axis of the frame, the higher the strength of this portion of the frame, and the lower softness. Conversely, the less junctions in each plane perpendicular to a longitudinal axis of the frame, the lower the strength of this portion of the frame, and the higher softness.

The inventors of the present disclosure have taken into account the various factors described above, and different numbers of edge members, ends of a frame in different shapes, and different distributions of junctions of a mesh are used in the design of a frame, so as to achieve a different strength of the frame.

As shown in FIG. 6a, the frame 600a includes three edge members 620 arranged at each of the proximal end and the distal end of the frame, taking triangular mesh units as ends. As shown in FIG. 6b, the frame 600b includes two edge members 620 arranged at each of the proximal end and the distal end of the frame, taking quadrilateral mesh units as ends. As shown in FIG. 6c, the frame 600c includes three edge members 620 arranged at each of the proximal end and the distal end of the frame, taking quadrilateral mesh units as ends. As shown in FIG. 6d, the frame 600d includes three edge members 620 arranged at each of the proximal end and the distal end of the frame, taking quadrilateral mesh units as ends.

In the mesh in the middle region of the

frame

600a, 600b and 600d, there is at most two junctions in a plane perpendicular to the longitudinal axis of the frame. For example, the junctions 690 shown in the figures are positioned in the same radial plane perpendicular to the longitudinal axis. However, for the mesh in the middle region of the frame 600c, there is at most one junction in each radial plane perpendicular to the longitudinal axis of the frame. That is, each mesh junction is positioned in a different plane perpendicular to the longitudinal axis. As shown in FIG. 6c, junctions 650 are designed in a staggered manner. Through this design, overlapping of junctions in each circumferential direction of the frame can be reduced, thereby improving the overall softness of the frame, and the frame can be conveniently withdrawn into the catheter.

In addition, in FIG. 6c, the middle region of the frame 600c includes two types of parallelogram units having different areas, with the parallelogram unit of the upper edge portion having a larger area. This design may reduce a metal portion of the frame, so as to further improve the softness of the frame. Moreover, through this design, a process for machining the frame may be easy. The reason is that in a process of cutting a cylindrical material into a mesh, the mesh on one side of a circumference of the frame is designed to have a larger area, such that excessive concentration of heat in a laser cutting process can be avoided, and a pipe can be fully utilized.

In an exemplary embodiment, the parallelogram unit of the frame has an area of 5 mm ² -30 mm ².

FIG. 7a is an exemplary perspective view of a thrombectomy device having an open middle region according to an embodiment of the present disclosure. For a frame 700a of the thrombectomy device shown in FIG. 7a, the left edge member 720 and the right edge member 760 are separated from each other to form an open frame structure with a longitudinal opening in the middle region 740.

FIG. 7b is an exemplary perspective view of a thrombectomy device having a closed middle region according to an embodiment of the present disclosure. For a frame 700b of the thrombectomy device shown in FIG. 7b, the left edge member 720 is engaged with the right edge member 760 in the middle region of and frame 700b to form a closed middle region 740.

Compared with the closed frame 700b shown in FIG. 7b, the open frame 700a shown in FIG. 7a has a better softness and has a smaller size after being contracted. Compared with the open frame, the closed frame is more easily preformed into a size having a larger expanding diameter.

The reason is that in a common process for machining a frame, a core shaft having a diameter larger than the inner diameter of an original pipe may be used in the tube for support, so as to shape the frame into a size having a large diameter. However, in a process for machining the open frame, if a core shaft having a larger diameter is used, only the longitudinal opening in the middle region of the frame may be larger, and the mesh may not be deformed, such that the frame may not be shaped into a size having a large diameter. For the closed frame, a core shaft having a larger diameter may be placed in a material in the shape of a pipe, and a mesh of the frame is deformed to adapt to the diameter of the core shaft, such that the frame can be preformed into a size having a large diameter.

As shown in FIG. 8a, a thrombus 820 is found in an intracranial blood vessel 810. As shown in FIG. 8b, a guide wire 830 guides a microcatheter 840 to approach the thrombus 820 through a percutaneous procedure. For example, X-ray and other imaging techniques are used to position the thrombus and direct the guide wire and the microcatheter to move to a target position in the blood vessel. As shown in FIG. 8c, the guide wire 830 guides the microcatheter 840 to advance through the thrombus 820 until a distal end of the microcatheter 840 exceeds the thrombus 820. As shown in FIG. 8d, after the microcatheter 840 passes through the thrombus 820, the guide wire 830 is withdrawn from the body, and the microcatheter 840 remains in place. As shown in FIG. 8e, the thrombectomy device 850 is conveyed to the distal end of the microcatheter 840 through a channel of the microcatheter 840. As shown in FIG. 8f, the microcatheter 840 is withdrawn but the thrombectomy device 850 remains in place, such that the thrombectomy device is released from the microcatheter. As shown in FIG. 8g, the microcatheter 840 is withdrawn, the thrombectomy device 850 is completely released and expands in all directions under the action of elasticity thereof, and a frame of the thrombectomy device captures the thrombus positioned around the frame. For example, the thrombus is captured by the middle region of the mesh. Finally, as shown in FIG. 8h, the thrombectomy device and the captured thrombus are withdrawn from the body, for example, withdrawn by a suction catheter.

In an exemplary embodiment, the microcatheter 840 may have an inner diameter of 0.0165 inch, 0.021 inch or 0.027 inch.

According to the thrombectomy device in the present disclosure, if thrombus fragments are generated in the process of withdrawing the captured thrombus, theses fragments will be further netted by the polymeric membrane and will not flow back into the blood vessel. Moreover, the holes on the polymeric membrane can guarantee smooth blood flowing without affecting a normal blood flowing speed. Therefore, the thrombectomy device in the present disclosure can reduce a risk of secondary occlusion of a blood vessel during a thrombectomy procedure.

The above embodiments are described herein by way of examples only. Many variations are possible without departing from the scope of the present disclosure as defined in the claims. Although various examples and other information are used to explain various aspects within the scope of the appended claims, specific functions or configurations in such examples should not be used as limitations to the claims, as those of ordinary skill in the art will be able to use the examples of these claims to derive various implementations.

Furthermore, although some subject matter may be described herein in exemplary languages of specific structural features and/or method steps, it should be understood that the subject matter defined in the claims is not necessarily limited to the described features or actions. For example, such functions may be differently distributed or executed in assemblies other than those marked herein. The described features and steps are disclosed only as examples of assemblies of the system and method within the scope of the appended claims.

Claims

A device for removing a substance from a blood vessel, the device comprising:

a foldable frame, wherein the frame is provided with a proximal end and a distal end and comprises edge members arranged near the proximal end and the distal end of the frame respectively, and a mesh extending between the edge members, when an action of an external force is removed, the frame is capable of expanding into a cylinder shape under an action of elasticity of a material of the frame, and the frame is provided with oblique openings at both the proximal end and the distal end; and

a polymeric membrane having holes, wherein the polymeric membrane is engaged with the distal end of the frame, and when the frame expands into the cylinder shape, the polymeric membrane spans the oblique opening of the frame at the distal end.
The device according to claim 1, wherein the polymeric membrane is engaged with the edge member without covering the mesh.
The device according to claim 1, wherein when the frame expands, a middle region is formed between the oblique openings at the proximal end and the distal end, and the middle region has a longitudinal size longer than a longitudinal length of the oblique openings.
The device according to claim 1, wherein when the frame expands, a longitudinal axis of the cylinder shape extends from the proximal end to the distal end, and in each plane perpendicular to the longitudinal axis, there is no more than two junctions of elements of the mesh.
The device according to claim 1, wherein the mesh comprises a plurality of parallelogram units, the parallelogram unit comprising four elongated elements connected at the junctions.
The device according to claim 5, wherein the parallelogram units have different areas.
The device according to claim 1, comprising two edge members converging toward the proximal end of the frame, wherein there is at least one quadrilateral unit at an interface between the two edge members and the mesh.
The device according to claim 1, comprising three edge members converging toward the proximal end of the frame, wherein there is at least one triangular unit at an interface between the three edge members and the mesh.
The device according to claim 1, comprising three edge members converging toward the proximal end of the frame, wherein there is at least one quadrilateral unit at an interface between the three edge members and the mesh.
The device according to claim 1, further comprising a push wire, wherein the edge members arranged at the proximal end of the frame converge at one end of the push wire.
The device according to claim 10, wherein the push wire comprises a positioning member configured to match a corresponding positioning structure in a push rod.
The device according to claim 11, further comprising a developing member positioned between the positioning member and the proximal end of the frame.
The device according to claim 1, wherein the holes are uniformly distributed on the polymeric membrane.
The device according to claim 1, wherein the polymeric membrane’s material is selected from E-polytetrafluoroethylene, polyethylene or polyethylene terephthalate.
The device according to claim 3, wherein the edge members comprise a left edge member and a right edge member, wherein the left edge member and the right edge member are joined with each other at the middle region of the frame, so as to form a closed middle region of the frame.
The device according to claim 3, wherein the edge members comprise a left edge member and a right edge member, and the left edge member and the right edge member are separated from each other at the middle region of the frame, so as to form an open middle region of the frame.
The device according to claim 1, wherein the hole has an approximately round or ellipse shape having a diameter/major axis of 0.1 mm -2.5 mm, and a distance between the holes is 0.5 mm -5 mm.
The device according to claim 1, wherein the frame has a diameter of 3 mm -7 mm and a length of 15 mm -70 mm in an expanding state.
The device according to claim 1, wherein the frame is sized such that in a folded state, the frame is accommodatable within a catheter having an inner diameter of 0.0165 inch -0.027 inch.
The device according to claim 5, wherein the parallelogram unit has an area of 5 mm ² -30 mm ².