CN117814951B - Distal embolic protection device - Google Patents

Abstract

The present invention belongs to the technical field of medical devices, and specifically relates to a distal embolic protection device. The distal embolic protection device of the present invention is used to prevent distal vascular embolism, and includes: 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 thrombi; a push rod, the push rod has a cavity section, and the push rod of the cavity section has a fluid delivery channel, and 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. The distal embolic protection device of the present invention can open the filter screen by filling the hollow tube with fluid, and can achieve adhesion to the blood vessel cavity by controlling the size of the fluid filling pressure, which helps to improve the capture efficiency of plaques and reduce the risk of plaque escape.

Description

Distal embolic protection device

Technical Field

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

Background Art

Atherosclerotic stenosis of peripheral blood vessels, coronary arteries, and carotid arteries can be treated with balloon dilatation and/or stent implantation to restore the original lumen and blood flow. However, during this process, the plaques at the stenotic site may be broken or detached due to the external force of the balloon and/or stent. If they drift to the distal blood vessels with the blood, they may cause embolism. In particular, when the plaques drift to the cerebral blood vessels, they may cause ischemic stroke, posing a huge threat to the patient's life, health, and safety. Therefore, distal embolic protection during stenosis treatment surgery is gradually becoming a consensus and routine operation in clinical practice.

Existing distal embolic protection devices can be divided into woven and coated types according to their manufacturing process. The filter screens are all made of a polymer or other material membrane with a certain pore size covered on the surface of a metal frame. However, regardless of the wire used in the woven type protection device or the frame of the coated type protection device, the material is generally nickel-titanium, and the principle of opening the filter screen is to utilize the superelasticity of nickel-titanium alloy. However, the filter screen woven or cut by the metal material has a large structural stress, and there is room for further improvement in the degree of fit to the blood vessel. It may also cause vasospasm in the patient during the process of opening the filter screen, or damage the blood vessel wall, causing the risk of dissection and bleeding.

According to the relative position of the filter and the push rod, the existing distal embolic protection device can be divided into eccentric type and coaxial type. The eccentric protection device has the advantage 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, so that the plaque is at risk of escaping from the gap between the filter and the blood vessel; the coaxial umbrella overcomes the disadvantages of the eccentric 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, and the plaque collides with the connecting rod or connecting wire and breaks into smaller plaques, which may lead to failure to capture, increasing the risk of distal embolism.

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

Summary of the invention

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.

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, the push rod of the cavity section has a fluid delivery channel, and 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 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.

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.

Preferably, 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 is connected to the fluid delivery channel through the communication hole.

Preferably, 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.

Preferably, the filter screen has a connecting tube at one end close to the connecting hole, and the connecting tube is connected to the hollow tube; the connecting tube is arranged to pass through the connecting hole, extends 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 connecting hole.

Preferably, the connecting tube is sealed and connected to the communicating hole via a sealing sleeve; the sealing sleeve and the connecting tube are arranged in a one-to-one correspondence; or, a plurality of the connecting tubes are gathered in the same sealing sleeve; the connecting tube and the hollow tube are arranged integrally.

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

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.

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

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:

The main body of the filter of the distal embolic protection device of the present invention is composed of a hollow tube, and the push rod has a cavity section, and the fluid delivery channel of the cavity section is connected to the inner cavity of the hollow tube, so that the filter can be changed from a folded state to an unfolded state under fluid pressure by filling the inner cavity of the hollow tube, so that the filter can play a role in capturing plaques. In addition, the above-mentioned setting of the distal embolic protection device of the present invention makes it possible to adjust the softness of the filter by controlling the filling pressure of the fluid, and achieve better fit to the blood vessel cavity.

The distal embolic protection device of the present invention can adopt a coaxial design, avoiding the shortcoming of the eccentric protection device that the filter screen is poorly attached to the wall due to the misalignment of the push rod and the blood vessel. In addition, the distal embolic protection device of the present invention is a coaxial design, but there is no connection between the filter screen opening and the push rod. Instead, the filter screen opening is closed by the shape memory property of the memory alloy wire in the hollow tube at the maximum diameter of the filter screen opening. The filter screen can be closed without a catheter, so that the distal embolic protection device of the present invention has the advantage of a high capture rate of the eccentric protection device, and avoids the disadvantage of the plaque colliding with the connecting rod or connecting wire of the coaxial protection device and breaking into smaller plaques, which is safer.

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 staggering the polymer tubes. The material is softer than metal material, which can effectively reduce the stimulation to the blood vessels and avoid damaging the blood vessel walls.

In the distal embolic protection device of the present invention, the fluid filled may be a contrast agent; that is, when the fluid filled in the distal embolic protection device of the present invention is a contrast agent, the filter can be opened by filling with the contrast agent (the filter is in an expanded state), so that the filter can be fully visualized under X-rays, which makes it easier for doctors to judge the position of the filter, the opening state and the fit with the blood vessel wall, and can effectively improve the safety of the operation.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. Among them:

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

FIG2 is a side view of a distal embolic protection device provided by an embodiment of the present invention (the filter screen is in an expanded state);

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

FIG4 is a schematic cross-sectional view of a push rod provided in an embodiment of the present invention;

FIG5 is a schematic diagram of the structure of a filter screen provided by an embodiment of the present invention;

FIG6 is a schematic diagram of the structure of a filter screen provided by another embodiment of the present invention;

FIG. 7 is a schematic structural diagram of the assembly of the connecting pipe ( FIG. 6 ) and the communicating hole provided by an embodiment of the present invention;

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

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);

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);

FIG. 11 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.

Reference numerals:

1-developing spring; 2-filter; 3-push rod; 4-Luer adapter;

21-hollow tube; 211-joint; 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

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 belong to the scope of protection of the present invention.

In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and 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, and therefore should not be understood as a limitation on the present invention.

In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more features.

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 connection between two elements, indirect connection, or an interactive relationship between two elements.

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

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

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 the existing distal embolic protection device.

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 with staggered distribution and interconnected 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.

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 “unfolded state” means that the filter screen 2 is expanded at least in the radial direction to have a larger outer diameter.

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

The filter 2 of the distal embolic protection device of the present invention is mainly composed of hollow tubes 21 with staggered distribution and interconnected inner cavities (the density between the hollow tubes 21 is preferably such that blood can pass smoothly and plaques can be prevented from escaping from the pores of the filter 2), and the inner cavity of the hollow tube 21 is connected to the fluid delivery channel 311 of the push rod 3; when the fluid in the fluid delivery channel 311 flows to the inner cavity of the hollow tube 21, the pressure of the fluid will cause the filter 2 in the folded state to gradually expand until it reaches the unfolded state, so that the filter 2 can fit the blood vessel wall. In addition, the filter 2 can effectively capture plaques and reduce or prevent plaque escape. Furthermore, the distal embolic protection device of the present invention realizes the transition of the filter 2 from the folded state to the unfolded state by delivering fluid into the hollow tube 21 of the filter 2. Compared with the coaxial distal embolic protection device, the connecting rod and connecting line between the opening of the filter 2 and the push rod 3 are omitted (the area of the opening of the filter 2 is larger), the capture efficiency of plaques is higher, and the distal embolism caused by the failure to capture plaques caused by the collision of plaques with the connecting rod or connecting line and breaking into smaller plaques can be effectively avoided or reduced. In addition, the present invention fills the hollow tube 21 of the filter 2 with fluid so that the filter 2 is transformed from the folded state to the unfolded state under the pressure of the fluid, so that the softness of the filter 2 can be adjusted by controlling the pressure of the fluid filling, and a better fit to the blood vessel cavity can be achieved.

In a preferred embodiment of the present invention, the filter screen 2 is in an umbrella shape in the unfolded state, and the radial dimension of the filter screen 2 gradually decreases from the proximal end to the distal end; a memory alloy wire 22 is arranged in the hollow tube 21 at the proximal end of the filter screen 2, and the outer contour of the memory alloy wire 22 is adapted to the proximal outer contour of the filter screen 2. The memory alloy wire 22 is made of a memory alloy (for example, a nickel-titanium alloy, etc.). Among them, by making the filter screen 2 in an umbrella shape in the unfolded state and gradually reducing the radial dimension of the filter screen 2 from the proximal end to the distal end, it is helpful to ensure the effect of the filter screen 2 fitting the blood vessel wall, and reduce or avoid the escape of plaque from the gap between the filter screen 2 and the blood vessel wall; by arranging the memory alloy wire 22 in the hollow tube 21 at the proximal end of the filter screen 2, when the radial dimension of the memory alloy wire 22 changes, the memory alloy wire 22 can apply a force to the filter screen 2, causing the radial dimension of the filter screen 2 to change, thereby facilitating the switching between the folded state and the unfolded state of the filter screen 2. Furthermore, by using the memory alloy wire 22 made of a memory alloy material, the memory alloy wire 22 can be restored to its original state in the absence of fluid pressure.

Preferably, the memory alloy wire 22 is preconfigured to a folded state (for example, the memory alloy wire 22 can be preconfigured to a folded state by heat treating the memory alloy wire 22). When the fluid is transported into the hollow tube 21 of the filter 2, the memory alloy wire 22 is transformed into an unfolded state. After the fluid in the hollow tube 21 of the filter 2 flows out, the characteristics of the memory alloy will restore the filter 2 to a folded state. By preconfiguring the memory alloy wire 22 to a folded state, the filter 2 is also in a folded state in a natural state, which facilitates the distal embolic protection device of the present invention to be transported to a specific position of the target blood vessel through an interventional path. When the fluid in the filter 2 is drained, the pressure inside the filter 2 disappears, and the shape memory characteristics of the memory alloy wire 22 enable it to be restored to the initial state (folded state), and the opening of the filter 2 is closed (preferably, in the folded state, the proximal end of the filter 2 fits the push rod 3; that is, in the folded state, the proximal inner diameter of the filter 2 matches the outer diameter of the push rod 3), thereby preventing the captured plaque from escaping.

In addition, existing distal embolic protection devices all require the use of additional catheters to achieve the closure of the filter, and the catheter may damage the blood vessel wall, and there may be risks such as displacement of the filter and escape of captured plaques during the process. The distal embolic protection device of the present invention arranges a memory alloy wire 22 made of a memory alloy in the hollow tube 21 at the proximal end of the filter 2 (that is, the memory alloy wire 22 is located at the proximal opening of the filter 2), and the filter 2 can be closed by the memory alloy wire 22 (that is, the filter 2 is in a folded state), without the need for additional catheters, and can effectively avoid the risks of catheters piercing blood vessels and plaque escape during the process of catheter closing the filter.

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 makes it easy to connect the filter screen 2 and the push rod 3, and the filling or draining of the fluid in the hollow tube 21 of the filter screen 2 is achieved by controlling the flow of the fluid in the cavity section 31 of the push rod 3 at the proximal end, 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 or other methods (the filter screen 2 and the push rod 3 are sealed to avoid leakage of the fluid).

In a preferred embodiment of the present invention, the far end of the filter screen 2 has a joint 211, and the joint 211 is in a bell-mouth shape. One end of the joint 211 is connected to the hollow tube 21, and the other end of the joint 211 is connected to the connecting hole 312; at least part of the joint 211 is located in the fluid delivery channel 311, and is sealed and connected to the inner wall of the push rod 3 at the corresponding connecting hole 312. Preferably, the large mouth end of the joint 211 is located in the fluid delivery channel 311; by making the joint 211 in a bell-mouth shape, it is not only conducive to the fluid in the fluid delivery channel 311 entering the hollow tube 21, but also conducive to ensuring the sealing connection effect between the joint 211 and the inner wall of the push rod 3 at the corresponding connecting hole 312.

In a preferred embodiment of the present invention, the filter screen 2 has a connecting tube 212 at one end close to the connecting hole 312, and the connecting tube 212 is connected to the hollow tube 21; the connecting tube 212 is arranged to pass through the connecting 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 filling of the filter screen 2 can be easily achieved, 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 connecting hole 312.

In a preferred embodiment of the present invention, the connecting tube 212 is sealed and connected to the connecting hole 312 via 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, a plurality of connecting tubes 212 are gathered in the same sealing sleeve; the connecting tube 212 is provided integrally with the hollow tube 21.

In a preferred embodiment of the present invention, the hollow tube 21 is a polymer hollow tube. The wire material used in the commonly used braided vascular embolic protection device or the frame of the film-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 by 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 damage 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 wall.

In a preferred embodiment of the present invention, the filter screen 2 is coaxially arranged with the push rod 3. The present invention can realize 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 piece between the proximal end of the filter screen 2 and the push rod 3), which can not only overcome the disadvantages of the eccentric protective umbrella (when the eccentric distal embolic protection device is released on a tortuous blood vessel, the push rod 3 cannot be coaxial with the blood vessel, which will cause the filter screen 2 to be poorly attached to the wall), so that the distal embolic protection device of the present invention has the advantage of high capture rate of the eccentric protection device, and avoids the disadvantages of plaque breaking into smaller plaques after collision with the connecting rod or connecting line between the filter screen opening and the push rod of the coaxial protection device in the prior art, which is easy to cause plaque escape and difficult to capture plaque, and is safer.

In a preferred embodiment of the present invention, the push rod 3 further has a grinding section 32, which is arranged at the distal end of the cavity section 31, and the outer diameter of the grinding section 32 gradually decreases from the proximal end to the distal end. The arrangement of the grinding section 32 makes the distal end of the push rod 3 more flexible, which helps to improve the in-place performance of the filter screen 2.

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

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

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 used in braided protection devices or the frame of coated protection devices are generally made of nickel-titanium) usually need to add development points on the filter to achieve better development effects, but the full-body development of the filter cannot be achieved, and surface protrusions at the development points are caused, 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. By using a contrast agent as a fluid, the present invention can not only realize the expansion of the filter 2 while filling the filter 2 with the contrast agent, but also realize full-body development under X-rays, which makes it easier for doctors to judge the position of the filter 2, the opening state, and the fit with the blood vessel wall, etc., and can effectively improve the safety of the operation.

In a further preferred embodiment of the present invention, one end of the cavity section 31 away from the grinding section 32 is connected to the fluid supply device through a connector. By connecting the cavity section 31 of the push rod 3 to the fluid supply device using a connector, the transfer of the fluid (preferably, the fluid is a contrast agent) in the push rod 3 (and the filter 2) can be easily achieved.

More preferably, the connecting piece is a Luer adapter 4 (as shown in FIG. 11 ); the fluid supply device may be a syringe, a balloon inflation pump, or the like.

In a preferred embodiment of the present invention, as shown in FIG1 , the distal embolic protection device is mainly composed of three parts: a developing spring 1, a filter screen 2 and a push rod 3; wherein 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 in the blood vessel under X-ray, and the developing points 23 at the proximal and distal ends are used as welding points and fixed to the distal end of the push rod 3 by soldering. The filter screen 2 is a mesh structure composed of a polymer tube with a hollow inner cavity, into which a contrast agent can be passed 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 the shape is a hollow ring, which is passed on the memory alloy wire 22 made of nickel-titanium material 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 view of the overall structure of the distal embolic protection device of this embodiment in an open state; FIG3 is a schematic diagram of the structure 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 part of the push rod 3 other than the grinding section 32 is a cavity section 31; the connecting hole 312 is located at the distal end of the cavity section 31, and the filter screen 2 in FIG1 is sealedly connected to the push rod 3 through the connecting hole 312. As shown in FIG4, it is a cross-sectional view of the connection between the filter screen 2 and the push rod 3 in FIG1, the polymer hollow tube 21 of the filter screen 2 enters the push rod 3 through the connecting hole 312 shown in FIG3, the end (distal end) of the polymer hollow tube 21 is a trumpet-shaped opening, and is fixed to the push rod 3 (sealed and connected to the connecting hole 312) by hot melting, dispensing or other means, and the contrast agent can enter the inside of the polymer hollow tube 21 of the filter screen 2 through the cavity section 31, and the pressure of the contrast agent can make the filter screen 2 open, presenting an umbrella shape as shown in FIG1 and FIG2. As shown in FIG8 , it is a right view of the distal embolic protection device in the folded state of the filter 2; when the contrast agent is filled into the filter 2 through the cavity of the push rod 3, the filter 2 will, under the pressure of the contrast agent, stretch the memory alloy wire 22 into a circular ring shape and open it, presenting an umbrella shape as shown in FIG1 , and the shape change of the memory alloy wire 22 in this process is shown in FIG9 . The nickel-titanium alloy has shape memory properties, and its heat treatment qualitative process and the morphological changes in the process are shown in FIG10 . The memory alloy wire 22 is straightened and inserted into the polymer hollow tube 21 at the maximum diameter of the filter 2. In the natural state, the filter 2 of the distal embolic protection device is in the folded state shown in FIG8 , which is convenient for delivery to the specific position of the target blood vessel through the interventional path. After the contrast agent is discharged, the internal pressure of the filter 2 disappears, and the memory alloy wire 22 (made of nickel-titanium alloy) returns to its initial state due to the shape memory property of the material, and closes the opening of the filter 2, thereby preventing the captured plaque from escaping. The distal embolic protection device can be connected to a device such as a syringe or a balloon filling pump through a Luer adapter 4 or other connector as shown in FIG. 11 , and contrast agent can be filled into the filter 2 through the syringe or the balloon filling pump, thereby achieving the opening of the filter 2 .

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 failure of the push rod 3 and the blood vessel to be 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 breakage, 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, thereby avoiding the risk of the catheter piercing 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.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (9)

1. A distal embolism protection device for preventing distal embolism of a blood vessel, characterized by comprising: 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; The distal end of the fluid delivery channel is provided with a connecting hole, and the inner cavity of the hollow tube at the distal end of the filter screen is connected to the fluid delivery channel through the connecting hole; the filter screen has a connecting tube at one end close to the connecting hole, and the connecting tube is connected to the hollow tube; the connecting tube is arranged through the connecting 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 tube is sealed and connected to the connecting hole; 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 the filter is umbrella-shaped in the expanded state, 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 as described in claim 2 is characterized in that the distal end of the filter has a joint, the joint 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. 4. The distal embolic protection device according to claim 1, characterized in that the connecting tube is sealedly connected to the communicating hole through 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. 5. The distal embolic protection device according to any one of claims 1 to 4, characterized in that the hollow tube is a polymer hollow tube, and the filter is coaxially arranged with the push rod. 6. The distal embolic protection device according to claim 2, characterized in that the push rod further has a grinding section, the grinding section 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. 7. The distal embolic protection device according to claim 6, characterized in that a developing spring is provided on the grinding section; The memory alloy wire is provided with developing points. 8. The distal embolic protection device according to any one of claims 1 to 4 or 6 to 7, characterized in that the fluid is a contrast agent; One end of the cavity section away from the grinding section is connected to the fluid supply device through a connecting piece. 9. The distal embolic protection device according to claim 5, wherein the fluid is a contrast agent; One end of the cavity section away from the grinding section is connected to the fluid supply device through a connecting piece.