Distal embolization protection device

Abstract

A distal embolization protection device, which is used for preventing distal vascular embolization. The distal embolization protection device comprises: a filter screen (2), the body of the filter screen (2) consisting of hollow tubes (21), which are distributed in cross and inner cavities of which are in communication with each other, and the filter screen (2) being configured to filter out thrombi; and a pushing rod (3), which has a cavity section (31), wherein the cavity section (31) has a fluid conveying channel (311), the fluid conveying channel (311) being in communication with the inner cavities of the hollow tubes (21) and being configured to convey a fluid to the inner cavities of the hollow tubes (21), so that the filter screen (2) is converted from a folded state into an unfolded state under the pressure of the fluid. In the distal embolization protection device, the filter screen can be opened by means of filling the hollow tubes with a fluid, and can fit onto a vascular lumen by means of controlling the magnitude of a fluid filling pressure, thereby helping to improve the plaque capturing efficiency and lowering the plaque escape risk.

Description

A distal embolic protection device Technical Field

[0001] The present invention belongs to the technical field of medical devices, and in particular relates to a distal embolism protection device. Background Art

[0002] Atherosclerotic stenosis of peripheral vessels, coronary arteries, and carotid arteries can be treated with balloon angioplasty and / or stent implantation to restore the original vessel lumen and blood flow. However, during this procedure, plaques at the stenotic site may be affected by the external forces of the balloon and / or stent, causing them to break or dislodge. If these plaques drift with the bloodstream to distal vessels, they may cause embolism. In particular, if plaques drift into cerebral vessels, they may cause ischemic stroke, posing a significant threat to the patient's life, health, and safety. Therefore, performing distal embolic protection during stenosis treatment surgery is becoming a common clinical practice and a routine procedure.

[0003] Existing distal embolic protection devices are categorized by their manufacturing process as either woven or membrane-coated. The filter consists of a metal frame covered with a polymer or other material membrane of a defined pore size. Whether the wire used in woven or membrane-coated devices is nickel-titanium, the frame is typically made of nickel-titanium. The mechanism for opening the filter is the superelasticity of the nickel-titanium alloy. However, these metal-woven or cut filters exhibit significant structural stress, leaving room for improvement in their adherence to blood vessels. Furthermore, the opening process can potentially cause vasospasm or damage the vessel wall, leading to the risk of dissection and bleeding.

[0004] According to the relative position of the filter and the push rod, existing distal embolic protection devices can be divided into eccentric and coaxial types. The advantage of the eccentric type protection device is that the filter opening is completely open without any obstruction, and the plaque capture rate is high. However, its disadvantage is that when placed in a tortuous blood vessel, the push rod cannot be coaxial with the blood vessel, resulting in the filter not being able to fit the blood vessel well, and there is a risk that the plaque will escape from the gap between the filter and the blood vessel. The coaxial type umbrella overcomes the disadvantages of the eccentric type umbrella, but in order to close the opening of the umbrella after use and to recycle the umbrella, it is usually necessary to set several connecting rods or connecting wires between the filter opening and the push rod, which reduces the plaque capture rate. Moreover, the plaque will collide with the connecting rod or connecting wire and break into smaller plaques, which may make it impossible to capture, increasing the risk of distal embolism.

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

[0006] Summary of the Invention

[0007] The object of the present invention is to provide a distal embolic protection device to solve or improve the problems of high risk of plaque escape or low efficiency of plaque capture by the filter during use of the existing distal embolic protection device.

[0008] In order to achieve the above-mentioned purpose, the present invention provides the following technical solutions: a distal embolic protection device, comprising: a filter screen, the main body of the filter screen is composed of hollow tubes with staggered distribution and interconnected inner cavities, and the filter screen is used to filter blood clots; a push rod, the push rod has a cavity section, and the push rod of the cavity section has a fluid delivery channel, which is connected to the inner cavity of the hollow tube and is used to deliver fluid to the inner cavity of the hollow tube so that the filter screen can be transformed from a folded state to an expanded state under the pressure of the fluid; at least in the radial direction, the size of the filter screen in the folded state is smaller than the size of the filter screen in the expanded state.

[0009] Preferably, the filter is umbrella-shaped in the expanded state, and the radial size of the filter gradually decreases from the proximal end to the distal end; a memory alloy wire is provided in the hollow tube at the proximal end of the filter, and the outer contour of the memory alloy wire is adapted to the proximal outer contour of the filter.

[0010] Preferably, a communicating hole is provided at the distal end of the fluid delivery channel, and the inner cavity of the hollow tube at the distal end of the filter is connected to the fluid delivery channel through the communicating hole.

[0011] Preferably, the far end of the filter screen has a connector, which is bell-shaped, one end of the connector is connected to the hollow tube, and the other end of the connector is connected to the connecting hole; at least part of the connector is located in the fluid delivery channel and is sealed and connected to the inner wall of the push rod corresponding to the connecting hole.

[0012] Preferably, the filter has a connecting tube at one end close to the communicating hole, and the connecting tube is connected to the hollow tube; the connecting tube is arranged to pass through the communicating hole, extend into the fluid delivery channel and has a liquid inlet, and the connecting tube and the hollow tube are configured to produce a capillary phenomenon; the outer wall of the connecting tube is sealed and connected to the communicating hole.

[0013] Preferably, the connecting pipe is sealed and connected to the communicating hole through a sealing sleeve; the sealing sleeve and the connecting pipe are arranged in a one-to-one correspondence; or, a plurality of the connecting pipes are gathered in the same sealing sleeve; the connecting pipe and the hollow pipe are arranged integrally.

[0014] Preferably, the hollow tube is a polymer hollow tube, and the filter screen is coaxially arranged with the push rod.

[0015] Preferably, the push rod further has a grinding section, which is arranged at the distal end of the cavity section, and the outer diameter of the grinding section gradually decreases from the proximal end to the distal end.

[0016] Preferably, a developing spring is provided on the grinding section; and a developing point is provided on the memory alloy wire.

[0017] Preferably, the fluid is a contrast agent; and one end of the cavity section away from the grinding section is connected to a fluid supply device via a connector. Beneficial effects:

[0018] The filter body of the distal embolic protection device of the present invention is composed of a hollow tube, and the push rod has a hollow section. The fluid delivery channel of the hollow section communicates with the inner lumen of the hollow tube. By filling the inner lumen of the hollow tube with fluid, the filter can be transformed from a folded state to an unfolded state under fluid pressure, enabling the filter to capture plaque. Furthermore, the aforementioned configuration of the distal embolic protection device of the present invention allows the filter's flexibility to be adjusted by controlling the fluid filling pressure, achieving a better fit within the vascular lumen.

[0019] The distal embolic protection device of the present invention can adopt a coaxial design, avoiding the shortcoming of eccentric protection devices, such as poor filter adhesion caused by the misalignment of the push rod and the blood vessel. Furthermore, the distal embolic protection device of the present invention is coaxial in design, but without any connection between the filter opening and the push rod. Instead, the filter opening is closed by the shape memory properties of a memory alloy wire within a hollow tube at the maximum diameter of the filter opening. This allows the filter to be closed without a catheter, thus giving the distal embolic protection device of the present invention the advantage of a high capture rate of eccentric protection devices while avoiding the disadvantage of plaques being broken into smaller pieces by collision with the connecting rod or wire of coaxial protection devices, resulting in greater safety.

[0020] The hollow tube in the distal embolic protection device of the present invention is a polymer tube. The filter screen is formed by connecting and interlacing polymer tubes. The material is softer than metal material, which can effectively reduce the stimulation to the blood vessels and avoid damage to the blood vessel walls.

[0021] In the distal embolic protection device of the present invention, the fluid filled therein may be a contrast agent; that is, when the fluid filled therein is a contrast agent, the filter can be opened by filling it with the contrast agent (the filter is in an expanded state), so that the filter can be fully visualized under X-rays, making it easier for doctors to determine the position, opening state, and adhesion of the filter to the blood vessel wall, thereby effectively improving the safety of the operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which constitute part of this specification, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. Among them:

[0023] FIG1 is a schematic diagram of the front structure of a distal embolic protection device provided by an embodiment of the present invention (the filter is in an expanded state);

[0024] FIG2 is a side view of a distal embolic protection device according to an embodiment of the present invention (the filter is in an expanded state);

[0025] FIG3 is a schematic diagram of the overall structure of a push rod provided by an embodiment of the present invention;

[0026] FIG4 is a schematic cross-sectional view of a push rod according to an embodiment of the present invention;

[0027] FIG5 is a schematic structural diagram of a filter screen provided by an embodiment of the present invention;

[0028] FIG6 is a schematic structural diagram of a filter screen provided by another embodiment of the present invention;

[0029] FIG7 is a schematic structural diagram of the assembly of the connecting pipe ( FIG6 ) and the communicating hole according to an embodiment of the present invention;

[0030] FIG8 is a side view of the distal embolic protection device provided by an embodiment of the present invention (the filter is in a folded state);

[0031] FIG9 is a schematic diagram of a process in which a memory alloy wire provided by an embodiment of the present invention changes from a folded state to an unfolded state (from left to right in the figure: folded state, intermediate state, and unfolded state);

[0032] FIG10 is a schematic diagram of a process in which a memory alloy wire provided by an embodiment of the present invention changes from an unfolded state to a folded state (from left to right in the figure: unfolded state, intermediate state, and folded state);

[0033] FIG11 is a schematic structural diagram of a connector (Luer adapter) in a distal embolic protection device provided by an embodiment of the present invention at different viewing angles.

[0034] Reference numerals: 1-developing spring; 2-filter; 3-push rod; 4-Luer adapter; 21-hollow tube; 211-connector; 212-connecting tube; 22-memory alloy wire; 23-developing point; 31-cavity section; 311-fluid delivery channel; 312-connecting hole; 32-grinding section. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention are within the scope of protection of the present invention.

[0036] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0037] In the description of the present invention, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0038] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or to implicitly indicate the quantity of the technical features indicated. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more features.

[0039] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, it can be a fixed connection or a movable connection, a detachable connection or a non-detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be internal communication between two elements, indirect communication, or an interactive relationship between two elements.

[0040] The present invention will be described in detail below with reference to the embodiments. It should be noted that the embodiments and features of the embodiments of the present invention can be combined with each other without conflict.

[0041] During use of the distal embolic protection device of the present invention, the end close to the operator is referred to as the proximal end, and the end away from the operator is referred to as the distal end.

[0042] The present invention provides a distal embolic protection device to address the problems of high risk of plaque escape or low efficiency of plaque capture by a filter during use of existing distal embolic protection devices.

[0043] As shown in Figures 1-10, the distal embolic protection device of an embodiment of the present invention includes: a filter screen 2, the main body of the filter screen 2 is composed of hollow tubes 21 that are staggered and interconnected with their inner cavities, and the filter screen 2 is used to filter blood clots; a push rod 3, the push rod 3 has a cavity section 31, and the push rod 3 of the cavity section 31 has a fluid delivery channel 311, which is connected to the inner cavity of the hollow tube 21 and is used to deliver fluid to the inner cavity of the hollow tube 21 so that the filter screen 2 can be transformed from a folded state to an unfolded state under the pressure of the fluid; at least in the radial direction, the size of the filter screen 2 in the folded state is smaller than the size of the filter screen 2 in the unfolded state.

[0044] The “folded state” means that the filter screen 2 is folded at least in the radial direction to have a smaller outer diameter; and the “expanded state” means that the filter screen 2 is expanded at least in the radial direction to have a larger outer diameter.

[0045] Preferably, in the folded state, the filter 2 can move axially within the blood vessel; in the unfolded state, the filter 2 can conform to the inner wall of the blood vessel to prevent thrombus from escaping from the gap between the filter 2 and the blood vessel wall. Preferably, the filter 2 has a certain degree of flexibility so that it can be deformed.

[0046] The filter 2 of the distal embolic protection device of the present invention is primarily composed of interlaced hollow tubes 21 with interconnected lumens (the density between the hollow tubes 21 is preferably such that blood can pass smoothly and plaque cannot escape from the pores of the filter 2). The lumens of the hollow tubes 21 are connected to the fluid delivery channel 311 of the push rod 3. When fluid in the fluid delivery channel 311 flows into the lumens of the hollow tubes 21, the pressure of the fluid causes the folded filter 2 to gradually expand until it reaches the expanded state, achieving adhesion between the filter 2 and the blood vessel wall. This effectively captures plaques, reducing or preventing plaque escape. Furthermore, the distal embolic protection device of the present invention achieves the transition of the filter 2 from a folded state to an expanded state by delivering fluid into the hollow tube 21 of the filter 2. Compared to coaxial distal embolic protection devices, the connecting rod and connecting wire between the filter 2 opening and the push rod 3 are omitted (the filter 2 opening has a larger area), resulting in higher efficiency in capturing plaques and effectively avoiding or reducing distal embolism caused by plaques colliding with the connecting rod or connecting wire and breaking into smaller plaques. In addition, the present invention fills the hollow tube 21 of the filter 2 with fluid to enable the filter 2 to transition from a folded state to an expanded state under the pressure of the fluid. This allows the softness of the filter 2 to be adjusted by controlling the pressure of the fluid filling, thereby achieving better fit to the vascular lumen.

[0047] In a preferred embodiment of the present invention, the filter screen 2 is umbrella-shaped in the expanded state, with the radial dimension of the filter screen 2 gradually decreasing from the proximal end to the distal end. A memory alloy wire 22 is disposed within a hollow tube 21 at the proximal end of the filter screen 2, the outer contour of the memory alloy wire 22 being compatible with the outer contour of the proximal end of the filter screen 2. The memory alloy wire 22 is made of a memory alloy (e.g., nickel-titanium alloy). The umbrella-shaped filter screen 2 in the expanded state and the gradually decreasing radial dimension of the filter screen 2 from the proximal end to the distal end help ensure that the filter screen 2 adheres to the blood vessel wall, reducing or preventing plaque from escaping through the gap between the filter screen 2 and the blood vessel wall. The memory alloy wire 22 is disposed within the hollow tube 21 at the proximal end of the filter screen 2, so that when the radial dimension of the memory alloy wire 22 changes, the memory alloy wire 22 applies a force to the filter screen 2, causing the radial dimension of the filter screen 2 to also change, thereby facilitating the switching of the filter screen 2 between the folded and expanded states. Furthermore, by using the memory alloy wire 22 made of a memory alloy material, the memory alloy wire 22 can return to its original state when there is no fluid pressure.

[0048] Preferably, the memory alloy wire 22 is preconfigured in a folded state (for example, by heat treating the memory alloy wire 22). When fluid is delivered into the hollow tube 21 of the filter 2, the memory alloy wire 22 transitions to an expanded state. After the fluid in the hollow tube 21 of the filter 2 flows out, the properties of the memory alloy cause the filter 2 to return to the folded state. By preconfiguring the memory alloy wire 22 in the folded state, the filter 2 naturally remains in the folded state, facilitating delivery of the distal embolic protection device of the present invention to a specific location in the target vessel via an interventional route. When the fluid in the filter 2 is drained, the pressure within the filter 2 dissipates, and the shape memory properties of the memory alloy wire 22 cause it to return to its initial state (folded state), closing the opening of the filter 2 (preferably, in the folded state, the proximal end of the filter 2 abuts against the push rod 3; i.e., in the folded state, the proximal inner diameter of the filter 2 matches the outer diameter of the push rod 3), thereby preventing the escape of captured plaque.

[0049] In addition, existing distal embolic protection devices all require an additional catheter to close the filter, which can lead to risks such as catheter damage to the blood vessel wall, filter displacement, and escape of captured plaque. The distal embolic protection device of the present invention disposes a memory alloy wire 22 made of a memory alloy within a hollow tube 21 at the proximal end of the filter 2 (i.e., the memory alloy wire 22 is located at the proximal opening of the filter 2). The memory alloy wire 22 can be used to close the filter 2 (i.e., the filter 2 is folded), eliminating the need for an additional catheter. This effectively avoids risks such as catheter damage to the blood vessel and plaque escape during the process of catheter closure of the filter.

[0050] In a preferred embodiment of the present invention, a connecting hole 312 is provided at the distal end of the fluid delivery channel 311, and the inner cavity of the hollow tube 21 at the distal end of the filter screen 2 is connected to the fluid delivery channel 311 through the connecting hole 312. The above arrangement facilitates the connection between the filter screen 2 and the push rod 3, and by controlling the flow of fluid in the cavity section 31 of the push rod 3 at the proximal end, the filling or draining of fluid in the hollow tube 21 of the filter screen 2 is achieved, thereby adjusting the outer diameter of the filter screen 2. Specifically, the filter screen 2 and the push rod 3 can be connected by hot melting, dispensing glue, or other methods (the filter screen 2 and the push rod 3 are sealed to prevent fluid leakage).

[0051] In a preferred embodiment of the present invention, the distal end of the filter screen 2 has a connector 211 in a bell-mouth shape. One end of the connector 211 is connected to the hollow tube 21, and the other end of the connector 211 is connected to the communication hole 312. At least a portion of the connector 211 is located within the fluid delivery channel 311 and is sealed to the inner wall of the push rod 3 at the corresponding communication hole 312. Preferably, the wide end of the connector 211 is located within the fluid delivery channel 311. The bell-mouth shape of the connector 211 facilitates the entry of fluid within the fluid delivery channel 311 into the hollow tube 21 and also helps ensure a sealed connection between the connector 211 and the inner wall of the push rod 3 at the corresponding communication hole 312.

[0052] In a preferred embodiment of the present invention, the filter screen 2 has a connecting tube 212 at one end near the communicating hole 312, and the connecting tube 212 is connected to the hollow tube 21; the connecting tube 212 is arranged to pass through the communicating hole 312, extends into the fluid delivery channel 311 and has a liquid inlet, and the connecting tube 212 and the hollow tube 21 are configured to produce a capillary phenomenon (when there is liquid in the fluid delivery channel 311, under the capillary action of the connecting tube 212 and the hollow tube 21, the liquid can enter the connecting tube 212 and the hollow tube 21 under the action of the capillary force, and then the filter screen 2 can be easily filled, so that the memory alloy wire 22 is changed from a folded state to an unfolded state); the outer wall of the connecting tube 212 is sealed and connected to the communicating hole 312.

[0053] In a preferred embodiment of the present invention, the connecting tube 212 is sealed and connected to the communicating hole 312 through a sealing sleeve (not shown in the figure) (the provision of the sealing sleeve helps to ensure the effect of the sealed connection; for example, the sealing sleeve can be made of a flexible material, etc.); the sealing sleeve and the connecting tube 212 are provided in a one-to-one correspondence; or, multiple connecting tubes 212 are gathered in the same sealing sleeve; the connecting tube 212 is provided integrally with the hollow tube 21.

[0054] In a preferred embodiment of the present invention, the hollow tube 21 is a polymer hollow tube. The wire material used in the conventional braided vascular embolic protection device or the frame of the membrane-coated protection device in the prior art is generally made of nickel titanium, and the principle of opening the filter is to utilize the shape memory properties of nickel titanium alloy. However, the filter woven or cut from metal materials has a large structural stress, and there is room for further improvement in the degree of fit to the blood vessels. It may also cause vasospasm in the patient during the opening of the filter, or cause damage to the blood vessel wall, causing dissection and bleeding risks. The present invention adopts a filter 2 made of polymer material (that is, the hollow tube 21 is a polymer hollow tube). The polymer material is softer and more compliant than the metal material (for example, nickel titanium alloy) commonly used in the distal embolic protection device of the prior art, and can effectively reduce the stimulation to the blood vessels and avoid damage to the blood vessel walls.

[0055] In a preferred embodiment of the present invention, the filter screen 2 is coaxially arranged with the push rod 3. By coaxially arranging the filter screen 2 with the push rod 3, the present invention can achieve the state switching of the filter screen 2 between the folded state and the unfolded state by filling the hollow tube 21 of the filter screen 2 with fluid or draining the fluid (there is no connecting member between the proximal end of the filter screen 2 and the push rod 3). This not only overcomes the disadvantages of the eccentric protective umbrella (when the eccentric distal embolic protection device is released into a tortuous blood vessel, the push rod 3 cannot be coaxial with the blood vessel, resulting in poor adhesion of the filter screen 2 to the wall), but also enables the distal embolic protection device of the present invention to have the advantage of a high capture rate of the eccentric protection device, and avoids the disadvantages of the coaxial protection device in the prior art, such as the plaque being broken into smaller plaques after colliding with the connecting rod or connecting line between the filter screen opening and the push rod, which easily causes the plaque to escape and the plaque capture is difficult, thus being safer.

[0056] In a preferred embodiment of the present invention, push rod 3 further includes a grinding section 32, which is disposed at the distal end of cavity section 31. The outer diameter of grinding section 32 gradually decreases from the proximal end to the distal end. The provision of grinding section 32 provides greater flexibility at the distal end of push rod 3, thereby improving the placement of filter screen 2.

[0057] Preferably, the grinding section 32 is solid and can be formed by multi-stage grinding, and the material can be nickel-titanium alloy or stainless steel.

[0058] In a preferred embodiment of the present invention, a developing spring 1 is provided on the grinding section 32; and developing points 23 are provided on the memory alloy wire 22. Specifically, the developing spring 1 can be wound from platinum-iridium alloy wire, gold wire, or other metal wire with good developing effects, and is used to indicate the position of the distal end of the distal embolic protection device of the present invention within the blood vessel under X-rays; further, the developing spring 1 can be sleeved on the outer wall of the grinding section 32, and then fixed to the distal end of the push rod 3 (i.e., the grinding section 32) by soldering at the proximal and distal end points of the developing spring 1. The developing points 23 on the memory alloy wire 22 can be made of platinum-iridium alloy, gold, or other metal materials with good effects, and the number can be 3, 4, 6, 8, etc. The developing points 23 can be in the shape of a hollow ring; after the developing points 23 are passed through the memory alloy wire 22, they can be further fixed to the surface of the memory alloy wire 22 by pressing and gripping.

[0059] The inventors found in their research that due to the general development effect of nickel-titanium materials, existing distal embolic protection devices (for example, the wire materials used in braided protection devices or the materials of the frames of membrane-coated protection devices are generally nickel-titanium) usually need to add development points on the filter to achieve better development effects. However, the filter cannot be fully developed, and the surface at the development points is raised, which poses a risk of irritation and scratching of blood vessels. In order to solve the above technical problems, in a preferred embodiment of the present invention, the fluid is a contrast agent. In the present invention, by using a contrast agent as a fluid, the filter 2 is filled with the contrast agent, which not only realizes the expansion of the filter 2, but also realizes full-body development under X-rays, making it easier for doctors to judge the position of the filter 2, the opening state, and the fit of the filter 2 with the blood vessel wall, etc., and can effectively improve the safety of the operation.

[0060] In a further preferred embodiment of the present invention, the end of the cavity section 31 remote from the grinding section 32 is connected to a fluid supply device via a connector. By connecting the cavity section 31 of the push rod 3 to the fluid supply device using the connector, the fluid (preferably, a contrast agent) in the push rod 3 (and the filter 2) can be conveniently transferred.

[0061] More preferably, the connecting piece is a Luer adapter 4 (as shown in FIG11 ); the fluid supply device may be a syringe, a balloon inflation pump, or the like.

[0062] In a preferred embodiment of the present invention, as shown in FIG1 , the distal embolic protection device mainly consists of three parts: a developing spring 1, a filter screen 2, and a push rod 3. The developing spring 1 is wound with platinum-iridium alloy wire, gold wire, or other metal wire with good developing effect, and is used to indicate the position of the distal end of the embolic protection device within the blood vessel under X-rays. The developing points 23 at the proximal and distal ends of the developing spring 1 serve as welding points and are fixed to the distal end of the push rod 3 by soldering. The filter screen 2 is a mesh structure made of a polymer tube with a hollow inner cavity. A contrast agent can be passed into the interior and the filter screen 2 is opened under the pressure of the contrast agent, so that the filter screen 2 is umbrella-shaped with a large diameter at the proximal end and a small diameter at the distal end; the developing points 23 are made of platinum-iridium alloy, gold or other metal materials with good developing effects, and the number can be 3, 4, 6, 8, etc., and their shape is hollow ring, which is passed through the memory alloy wire 22 made of nickel-titanium and fixed to the surface of the memory alloy wire 22 by pressing or other means; the developing points 23 and the memory alloy wire 22 are both located inside the polymer hollow tube 21 at the maximum opening diameter of the filter screen 2. FIG2 is a right side view of the overall structure of the distal embolic protection device of this embodiment in the open state; FIG3 is a schematic structural diagram of the push rod 3, wherein the grinding section 32 at the distal end thereof is a solid structure formed by multi-stage grinding and made of nickel-titanium alloy or stainless steel; the portion of the push rod 3 other than the grinding section 32 is a hollow section 31; a connecting hole 312 is located at the distal end of the hollow section 31, and the filter screen 2 in FIG1 is sealedly connected to the push rod 3 through the connecting hole 312. FIG4 is a cross-sectional view of the connection between the filter screen 2 and the push rod 3 in FIG1, wherein the polymer hollow tube 21 of the filter screen 2 enters the push rod 3 through the connecting hole 312 shown in FIG3. The distal end (distal end) of the polymer hollow tube 21 is a trumpet-shaped opening and is fixed to the push rod 3 (sealed with the connecting hole 312) by hot melt, adhesive dispensing, or other means. Contrast agent can enter the interior of the polymer hollow tube 21 of the filter screen 2 through the hollow section 31, and the pressure of the contrast agent can cause the filter screen 2 to open, forming the umbrella shape shown in FIG1 and FIG2. Figure 8 shows a right-side view of the distal embolic protection device with the filter 2 in its folded state. When contrast agent is introduced into the filter 2 through the cavity of the push rod 3, the pressure from the contrast agent causes the memory alloy wire 22 to expand into a circular ring, forming the umbrella shape shown in Figure 1. The shape change of the memory alloy wire 22 during this process is shown in Figure 9. Nickel-titanium alloy exhibits shape memory properties. Its heat treatment characterization process and the resulting morphological changes are shown in Figure 10. The memory alloy wire 22 is straightened and inserted into the polymer hollow tube 21 at the largest diameter of the filter 2. In its natural state, the filter 2 of the distal embolic protection device assumes the folded state shown in Figure 8, facilitating delivery to a specific location in the target vessel via an interventional approach. After the contrast agent is removed, the internal pressure of the filter 2 dissipates, and the memory alloy wire 22 (made of nickel-titanium alloy) returns to its initial state due to the material's shape memory properties, closing the filter 2 opening and preventing the escape of captured plaque.The distal embolic protection device can be connected to a device such as a syringe or a balloon inflation pump through a Luer adapter 4 or other connector as shown in FIG11 , and contrast agent can be filled into the filter 2 through the syringe or balloon inflation pump to open the filter 2 .

[0063] The distal embolic protection device of the above embodiment has the following advantages over the prior art: (1) The coaxial design of the filter 2 and the push rod 3 can effectively avoid the poor adhesion of the filter 2 to the wall caused by the push rod 3 and the blood vessel not being coaxial when the eccentric distal embolic protection device is released into a tortuous blood vessel; (2) The distal embolic protection device of this embodiment opens the filter 2 by filling it with contrast agent, and no connection is required between the opening of the filter 2 and the push rod 3, which can effectively improve the capture efficiency, prevent plaque fragmentation, and reduce the risk of distal embolism; (3) The filter 2 is composed of a polymer hollow tube 21, which is softer and more compliant than metal materials such as nickel titanium, can reduce the stimulation to the blood vessel, and can achieve full adhesion of the filter 2 to the target blood vessel by adjusting the pressure of the contrast agent; (4) The filter 2 is closed by the nickel titanium wire (i.e., the memory alloy wire 22) at the opening, without the need for an additional catheter, avoiding the risk of the catheter puncturing the blood vessel and the risk of plaque escape during the process of the catheter closing the filter 2. (5) The filter 2 is opened by contrast agent, and the entire filter 2 is visible under X-ray, which is convenient for doctors to judge and operate.

[0064] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A distal embolism protection device for preventing distal vascular embolism, characterized in that: include: A filter screen, wherein the main body of the filter screen is composed of hollow tubes which are staggered and have interconnected inner cavities, and the filter screen is used to filter blood clots; A push rod, wherein the push rod has a cavity section, and the push rod of the cavity section has a fluid delivery channel, wherein the fluid delivery channel is connected to the inner cavity of the hollow tube and is used to deliver fluid to the inner cavity of the hollow tube so that the filter screen is transformed from a folded state to an unfolded state under the pressure of the fluid; At least in the radial direction, the size of the filter in the folded state is smaller than the size of the filter in the unfolded state.

2. The distal embolic protection device according to claim 1, characterized in that: In the unfolded state, the filter is in an umbrella shape, and the radial dimension of the filter gradually decreases from the proximal end to the distal end; A memory alloy wire is arranged in the hollow tube at the proximal end of the filter screen, and the outer contour of the memory alloy wire is matched with the outer contour of the proximal end of the filter screen.

3. The distal embolic protection device according to claim 2, characterized in that: A communication hole is provided at the distal end of the fluid delivery channel, and the inner cavity of the hollow tube at the distal end of the filter screen is connected with the fluid delivery channel through the communication hole.

4. The distal embolic protection device according to claim 3, characterized in that: The far end of the filter screen has a joint, which is in a bell-mouth shape. One end of the joint is connected to the hollow tube, and the other end of the joint is connected to the connecting hole; at least part of the joint is located in the fluid delivery channel and is sealed and connected to the inner wall of the push rod corresponding to the connecting hole.

5. The distal embolic protection device according to claim 3, characterized in that: The filter screen has a connecting pipe at one end close to the communicating hole, and the connecting pipe is connected to the hollow tube; The connecting tube is arranged through the communicating hole, extends into the fluid delivery channel and has a liquid inlet, and the connecting tube and the hollow tube are configured to generate a capillary phenomenon; The outer wall of the connecting pipe is sealed and connected to the communicating hole.

6. The distal embolic protection device according to claim 5, characterized in that: The connecting pipe is sealed and connected to the communicating hole via a sealing sleeve; The sealing sleeves are arranged one by one with the connecting pipes; or, a plurality of connecting pipes are gathered in the same sealing sleeve; The connecting pipe is integrally arranged with the hollow pipe.

7. The distal embolic protection device according to any one of claims 1 to 6, characterized in that: The hollow tube is a polymer hollow tube, and the filter screen is coaxially arranged with the push rod.

8. The distal embolic protection device according to claim 2, characterized in that: The push rod also has a grinding section, which is arranged at the distal end of the cavity section, and the outer diameter of the grinding section gradually decreases from the proximal end to the distal end.

9. The distal embolic protection device according to claim 8, characterized in that: The grinding section is provided with a developing spring; The memory alloy wire is provided with developing points.

10. The distal embolic protection device according to any one of claims 1 to 9, characterized in that: The fluid is a contrast medium; One end of the cavity section away from the grinding section is connected to the fluid supply device through a connecting piece.

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