A hierarchically arranged embolic protection device

Abstract

This invention provides a graded embolization protection device, belonging to the field of vascular interventional medical device technology. The device includes a delivery guidewire, with multiple protection units fixedly arranged at intervals at the distal end of the guidewire. Each protection unit has a proximal open end and a distal closed end, and each protection unit has a flexible support frame for support at a target location. Multiple open areas are formed on the support frame, and a soft, elastic filter membrane is arranged on the edge of each open area or on the sidewall of the entire support frame to cover the open area. In use, the multiple protection units are axially deployed graded along the target location, with the flexible support frame of each protection unit fully conforming to the inner wall of the blood vessel, and the soft, elastic filter membrane intercepting emboli in the blood flow. This addresses at least the technical problems of existing embolization protection devices, such as poor flexibility due to the high coverage of the rigid support structure, difficulty in adapting to complex vascular morphologies, and poor fit with the vascular wall, leading to embolism escape.

Description

Technical Field

[0001] This invention belongs to the field of vascular interventional medical device technology, specifically relating to a graded embolization protection device. Background Technology

[0002] During interventional vascular procedures (such as balloon angioplasty and stent implantation), plaques or thrombi at the site of vascular stenosis are prone to breakage and detachment under external force. These detached emboli can travel with the bloodstream to distal vessels, potentially causing distal vascular embolism and leading to serious complications such as ischemic stroke and myocardial infarction, threatening the patient's life. Therefore, embolization protection devices (commonly known clinically as "protective umbrellas") are crucial auxiliary instruments in interventional vascular surgeries, and their performance directly affects the safety and effectiveness of the procedure. Distal embolization protection devices, due to their wide applicability, have become the mainstream type used in clinical practice.

[0003] Existing embolism protection devices, such as the Chinese invention patent with document number CN118512282A, disclose a distal embolism protection device that uses a single conical filter or mesh structure. The entire structure is a mesh made of metal wires, and the mesh openings are mainly formed by the gaps between the metal wires. This results in a high metal coverage of the protective umbrella (i.e., a rigid support structure), poor flexibility, and difficulty in adapting to blood vessels of different diameters and high degrees of tortuosity. Especially in areas with complex vascular morphology, the device cannot flexibly deform with the direction of the blood vessel, does not fit tightly against the blood vessel wall, and is prone to gaps, allowing emboli to escape from the gaps.

[0004] Furthermore, existing single-protection-umbrella structures suffer from the following problems: their filter meshes are typically designed with uniform pore sizes to intercept all emboli larger than a certain size. In practical applications, this design results in all intercepted emboli congregating within the same filter, easily causing filter blockage, significantly affecting blood flow velocity, and increasing the risk of distal vessel ischemia. Conversely, increasing the mesh pore size to maintain blood flow allows smaller emboli to escape, failing to achieve comprehensive protection. Therefore, existing embolism protection devices struggle to strike a balance between ensuring unobstructed blood flow and achieving comprehensive interception.

[0005] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Summary of the Invention

[0006] The purpose of this invention is to provide a graded embolization protection device to at least solve the technical problems of existing embolization protection devices, such as poor flexibility due to high coverage of rigid support structures, difficulty in adapting to complex vascular morphologies, and easy embolism escape due to poor adhesion to the vascular wall.

[0007] To achieve the above objectives, the graded embolism protection device of the present invention provides the following technical solution: A graded embolism protection device includes a delivery guide wire, wherein a plurality of protection units are fixedly arranged at intervals at the distal end of the delivery guide wire, each protection unit having a proximal open end and a distal closed end, and each protection unit having a flexible support frame for support at a target position, the support frame having a plurality of open areas, and a soft elastic filter membrane for covering the open area is arranged on the edge of each open area or on the sidewall of the support frame as a whole. In use, multiple protection units unfold axially along the target location, with the flexible support frame of each protection unit fully conforming to the inner wall of the blood vessel, and the soft elastic filter membrane used to intercept emboli in the blood flow.

[0008] As a further optimized technical solution, in any two adjacent protection units, the distal end of one protection unit extends into the proximal end of the adjacent protection unit by a set distance.

[0009] As a further optimized technical solution, the graded embolism protection device also includes a recovery auxiliary structure, which is used to assist in gradually reducing the protection unit during recovery.

[0010] As a further optimized technical solution, the recovery auxiliary structure consists of pull wires arranged at intervals along the circumference of the protection unit. The distal end of each pull wire is fixedly connected to the proximal end of the protection unit, and the proximal end is used to receive pull, so that the proximal opening of the protection unit gradually closes during the recovery process, preventing the plug inside the protection unit from overflowing and escaping.

[0011] As a further optimized technical solution, the proximal end of the pull wire arranged on the near end of the protection unit is fixedly set on the conveying guide wire, and the proximal end of the pull wire on the remaining protection units is fixedly arranged on the adjacent protection unit located on the near side.

[0012] As a further optimized technical solution, among the multiple protection units, the pore size of the soft elastic filter membrane on the same protection unit is consistent, and among any two adjacent protection units, the pore size of the filter pore of the protection unit located near the end is larger than the pore size of the filter pore of the protection unit located far from the end.

[0013] As a further optimized technical solution, the support frame is integrally cut and formed using an elastic memory alloy.

[0014] As a further optimized technical solution, the soft elastic filter membrane is made of biocompatible polymer material, and the soft elastic filter membrane is fixed to the sidewall of the flexible support frame by hot pressing or adhesive bonding.

[0015] As a further optimized technical solution, in any two adjacent protection units, the distal end of one protection unit extends into the adjacent other protection unit to a depth of 1 / 5 to 1 / 3 of the total length of the protection unit into which it is extended.

[0016] As a further optimized technical solution, the flexible support frame has a perforation rate of 75%-90%. Beneficial effects: First, the present invention adopts a structure in which multiple protection units are arranged in a hierarchical manner. Each protection unit unfolds sequentially along the vascular axis to form multiple protective barriers. When the proximal protection unit has a small gap with the vascular wall due to the complex vascular morphology, causing some small emboli to escape, the distal protection unit can intercept the escaped emboli a second time, effectively preventing emboli from entering the distal vascular vessel and significantly improving the reliability of embolism protection.

[0017] Secondly, the protection unit of this invention employs a composite structure of a flexible support frame and a soft, elastic filter membrane. A large open area is formed on the support frame, covered by the soft, elastic filter membrane to achieve the filtration function. Compared to existing filter structures made entirely of metal wire mesh, the rigid support structure (flexible support frame) in this invention has a significantly reduced coverage area, resulting in a substantial improvement in the overall flexibility of the device. It can flexibly deform along the blood vessel's direction, closely conforming to the inner walls of various blood vessels, making it suitable for different blood vessel diameter ranges. This effectively avoids the technical problem of emboli escape due to inadequate fit.

[0018] Furthermore, the multiple protection units of the present invention are arranged in an axially stacked manner (the distal end extends into the proximal end of the adjacent protection unit), and the protection units can move relative to each other at the bend of the blood vessel, which further improves the passability and adaptability of the device in tortuous blood vessels, while ensuring continuous protection between the protection units.

[0019] Furthermore, by setting a pull wire as a recycling auxiliary structure, the present invention gradually closes the proximal opening of the protection unit during recycling by pulling, avoiding the risk of the plug being squeezed out or overflowing due to the instantaneous closure of the opening during recycling, thus achieving safe recycling.

[0020] Furthermore, this invention achieves a graded filtration effect by setting the mesh diameter of the proximal protection unit to be larger than that of the distal protection unit: the proximal protection unit intercepts large-sized emboli, while the distal protection unit intercepts small and medium-sized emboli. This ensures smooth blood flow and achieves comprehensive interception of emboli of all sizes. Compared with the existing single protective umbrella structure, this avoids the impact on blood flow velocity when all emboli are intercepted at the same time. Attached Figure Description

[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Wherein: Figure 1 This is a schematic diagram of the overall structure of an embodiment of the graded embolism protection device of the present invention; Figure 2 A schematic diagram of the flexible support frame structure of the protection unit of an embodiment of the graded embolism protection device of the present invention. Figure 3 This is a schematic diagram of the protection unit structure of an embodiment of the graded embolism protection device of the present invention; Figure 4 This is a schematic diagram illustrating the working state of an embodiment of the graded embolism protection device of the present invention.

[0022] In the diagram: 100, guidewire; 200, protection unit; 201, constant diameter zone; 202, variable diameter zone; 203, toothed protrusion; 210, flexible support frame; 211, open area; 220, soft elastic filter membrane; 221, filter pore; 300, drawing wire; 400, blood vessel; 500, embolus. Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0024] In the description of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. The terms "connected" and "linked" used in this invention should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; they can refer to a direct connection or an indirect connection through intermediate components. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances. Furthermore, the term "proximal end" uniformly refers to the end closer to the operator, while "distal end" refers to the end farther from the operator.

[0025] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0026] The shapes and sizes of the components in the accompanying drawings do not reflect the actual proportions of the product; they are only intended to illustrate the content of the invention.

[0027] To address the technical problems of existing embolism protection devices, such as poor flexibility due to high coverage of rigid support structures, difficulty in adapting to complex vascular morphologies, poor adhesion to the vessel wall leading to embolism escape, and the difficulty of achieving a balance between ensuring blood flow and comprehensive interception in single-stage protective umbrella structures, this invention provides a graded embolism protection device. This device includes a guidewire 100, with multiple protection units 200 fixedly arranged at intervals at the distal end of the guidewire 100. Each protection unit has a proximal open end and a distal closed end, and each protection unit 200 has a flexible support frame 210 for support against the vessel wall. Multiple open areas 211 are formed on the flexible support frame 210, and a soft, elastic filter membrane 220 is also provided on the flexible support frame 210 to cover the open areas. The membrane can be applied individually to each open area 211, or it can be applied as a whole to the side wall of the flexible support frame 210. The purpose is to use the soft, elastic filter membrane 220 to intercept emboli 500. Multiple protection units 200 are deployed in stages along the vascular axis to form multiple protective barriers; the flexible support skeleton 210 has a high perforation rate, which, together with the soft elastic filter membrane 220, significantly improves the flexibility of the device and allows it to fit tightly to the complex shape of the vascular inner wall; adjacent protection units 200 are arranged in a stacked manner, which can move relative to each other at the bends of the blood vessel to ensure the continuity of protection; the filter holes 221 on the protection units 200 are arranged in stages to achieve staged interception; during retrieval, the opening of the protection units 200 is gradually closed by the pulling wire 300 to prevent the embolus 500 from escaping.

[0028] Example 1 like Figure 1 , Figure 2 As shown, the graded embolism protection device includes a delivery guide wire 100 and three protection units 200 arranged at the far end of the delivery guide wire 100. The three protection units 200 are fixedly arranged at intervals along the axial direction of the delivery guide wire 100.

[0029] Specifically, the guide wire 100 is a metal wire with good pushing and torsion control, and its distal end passes through the center of each protection unit 200 in sequence and is fixedly connected to at least the distal end of each protection unit 200.

[0030] Each protection unit 200, in its operational state, is an approximately conical or cup-shaped structure with an open proximal end and a constricted distal end, forming a receiving cavity for intercepting emboli 500 in the bloodstream. In this embodiment, as... Figure 3As shown, each protection unit 200 has an integrally connected equal diameter region 201 and a variable diameter region 202. The equal diameter region 201 is located in the near end of the protection unit 200 and has a cylindrical or near-cylindrical structure with basically the same diameter in each cross section along the axial direction. The variable diameter region 202 is located in the far end of the protection unit 200 and has a conical or trumpet shape with a cross section diameter that gradually decreases from the near end to the far end. Traditional single-conical protective umbrellas have a gradually widening flared opening at the proximal end. After unfolding within the vessel 400, the contact between the protective umbrella and the vessel wall is linear or point-like, resulting in a small contact area. When the vessel 400 is irregular or curved, gaps can easily form at the edge of the opening, allowing the embolus 500 to escape. This solution, however, by arranging an equal-diameter zone 201, ensures that the proximal end of the protective unit 200 has a constant diameter. After unfolding within the vessel 400, its outer wall forms a surface contact with the inner wall of the vessel 400, rather than a line contact, significantly increasing the contact area and effectively preventing the embolus 500 from escaping. Furthermore, the axial length of the equal-diameter zone 201 provides sufficient contact depth, ensuring good adhesion even with slight bends or changes in the vessel 400. Additionally, the equal-diameter zone 201 provides stable support even at bifurcation or bends in the vessel 400, preventing tilting or displacement of the device due to uneven stress.

[0031] Specifically, each protection unit 200 has a flexible support frame 210 for support at the target location. The flexible support frame 210 is integrally cut from an elastic shape memory alloy (such as nickel-titanium alloy), possessing shape memory function and super elasticity. In its naturally unfolded state, the flexible support frame 210 has a frame structure with multiple open areas 211 formed on its sidewalls. These open areas 211 are large-sized hollow structures, not used for directly filtering emboli 500. The hollowness of the flexible support frame 210 is 75% to 90%, meaning that the solid area of ​​the rigid support structure accounts for only 10% to 25% of the outline area of ​​the protection unit 200. This gives the protection unit 200 good overall flexibility, allowing it to flexibly deform according to the curvature of the blood vessel 400. To achieve the function of filtering emboli 500, each open area 211 is individually covered with a soft elastic filter membrane 220, or the soft elastic filter membrane 220 can be covered on the entire sidewall of the flexible support frame 210. The purpose is to use the soft elastic filter membrane 220 to intercept emboli 500.

[0032] Furthermore, the flexible filter membrane 220 is made of a biocompatible polymer material (such as polyurethane, silicone rubber, or expanded polytetrafluoroethylene), possessing excellent flexibility and elasticity. The edges of the flexible filter membrane 220 are fixedly connected to the flexible support frame 210 by heat pressing or medical-grade adhesive. Simultaneously, multiple filter pores 221 are evenly distributed on the flexible filter membrane 220. The pore size of the filter pores 221 on the same protection unit 200 is consistent, but the pore size of the filter pores 221 on the three protection units 200 is different. Specifically, in any two adjacent protection units 200, the filter aperture 221 of the proximal protection unit 200 is larger than that of the distal protection unit 200. Thus, during embolism protection, blood carrying emboli 500 flows into the proximal protection unit 200. Larger emboli 500 are intercepted by the filter aperture 221 of the proximal protection unit 200, while smaller emboli 500 are carried by the blood flow through the proximal protection unit 200 into the distal protection unit 200. Because the filter aperture 221 of the proximal protection unit 200 is larger than that of the distal protection unit 200 (e.g., the proximal filter aperture 221 is 200 μm, and the distal filter aperture 221 is 100 μm), the distal protection unit 200 can further intercept small and medium-sized emboli 500 that the proximal protection unit 200 failed to capture, achieving graded filtration. This ensures both smooth blood flow and comprehensive interception of emboli 500 of various sizes.

[0033] Furthermore, in any two adjacent protective units 200, the distal end of one protective unit 200 extends into the proximal end of the other protective unit 200 to a depth of 1 / 5 to 1 / 3 of the axial length of the inserted protective unit 200. Thus, when the overlap depth is less than 1 / 5 of the axial length of the protective unit 200, adjacent protective units 200 are prone to separation in the tortuous state of the blood vessel 400, creating a protective gap; when the overlap depth is greater than 1 / 3 of the axial length of the protective unit 200, the relative movement between adjacent protective units 200 is restricted, affecting the device's passage through the tortuous blood vessel 400. Controlling the overlap depth within the range of 1 / 5 to 1 / 3 ensures both continuity of protection and good flexibility and passageability of the device.

[0034] Furthermore, the graded embolism protection device also includes a retrieval auxiliary structure to assist in the gradual reduction of the protection unit 200 during retrieval. In this embodiment, the retrieval auxiliary structure consists of pull wires 300 spaced circumferentially along the protection unit 200 to ensure balanced force during retrieval. Each protection unit 200 has four pull wires, and the distal end of each pull wire 300 is fixedly connected to the toothed protrusion 203 at the proximal end of the protection unit 200. The proximal end is used to receive pull, so that the proximal open position of the protection unit 200 gradually closes during retrieval, preventing the embolus 500 inside the protection unit 200 from escaping. Specifically, the pull wires 300 are made of biocompatible metal wires (such as nickel-titanium alloy wires or stainless steel wires) or polymer fiber filaments (such as polyester fibers), possessing sufficient tensile strength and flexibility.

[0035] Furthermore, the proximal end of the pull wire 300 arranged on the proximal protection unit 200 is fixedly mounted on the conveying guide wire 100. A fixing ring or crimping sleeve can be installed at a corresponding position on the conveying guide wire 100 to fix the proximal end of the pull wire 300 thereon. When the operator pulls the conveying guide wire 100 proximally, this set of pull wires 300 is tightened accordingly. The proximal ends of the pull wires 300 on the remaining protection units 200 are fixedly arranged on adjacent protection units 200 located proximal to each other. Specifically, as shown... Figure 1As shown, the proximal end of the pull wire 300 on the intermediate protection unit 200 is fixedly connected to the distal end or proximal edge of the flexible support frame 210 of the nearest protection unit 200; the proximal end of the pull wire 300 on the farthest protection unit 200 is fixedly connected to the flexible support frame 210 of the intermediate protection unit 200, thus forming a series linkage structure. In this way, when the protection unit 200 needs to be retrieved, the operator slowly pulls the guide wire 100 towards the proximal end, causing the protection unit 200 to gradually move towards the distal end of the retrieval device (usually a retrieval sheath). At this time, since the distal end of the pull wire 300 is fixed to the proximal edge of the nearest protection unit 200, the pulling force acts through the pull wire 300 on the proximal open edge of the protection unit 200, causing it to gradually enter the retrieval device and be subject to the radially centripetal constraint force of the retrieval device. During the traction process, the diameter of the proximal opening of the nearest protection unit 200 gradually decreases, from a fully expanded state (diameter equivalent to the inner diameter of the blood vessel 400) to a smaller diameter state. Because the closing process is gradual, the embolus 500 within the protection unit 200 is always encased by the soft elastic filter membrane 220 and will not escape from the opening edge. As the guidewire 100 continues to move proximally, the nearest protection unit 200 is pulled into the retrieval device. During this process, the traction wire 300 on the nearest protection unit 200 (the distal end of which is connected to the proximal end of the intermediate protection unit 200) is also gradually closed into the retrieval device. At this time, the proximal opening of the intermediate protection unit 200 also gradually closes under the radial constraint of the retrieval device. Thus, from proximal to distal, the opening ends of each protection unit 200 close sequentially. Once all the protection units 200 are retracted, the entire device becomes a long, thin strip and is stored in the recycling equipment, completing the recycling process.

[0036] The specific usage process of this device is as follows: First, the embolization protection device is inserted into the matching delivery sheath. The surgeon inserts the delivery sheath containing the device into the patient's peripheral blood vessel 400 (such as the femoral artery or radial artery) and slowly pushes it along the blood vessel 400 pathway. Under the real-time guidance of imaging equipment (such as DSA), the distal end of the delivery guidewire 100 and the retracted protection unit 200 are pushed to the distal position of the target treatment blood vessel 400, ensuring that all protection units 200 are located downstream of the target treatment area, providing comprehensive interception and protection for emboli 500 that may dislodge during subsequent surgery.

[0037] Then, after confirming that the device has reached the preset position, the delivery sheath is slowly retracted, releasing the constraint on the protection unit 200. The flexible support frame 210, utilizing the self-expansion properties of the nickel-titanium shape memory alloy, drives the protection unit 200 to unfold step by step. Multiple protection units 200 extend sequentially along the axial direction of the blood vessel 400, with adjacent protection units 200 unfolding sequentially. During the unfolding process, the flexible support frame 210 adaptively conforms to the inner wall of the blood vessel 400, and the soft elastic filter membrane 220 unfolds accordingly. At this time, the soft elastic filter membranes 220 of each protection unit 200 form multiple filtration barriers distributed along the axial direction of the blood vessel 400, completing the deployment of the device. The unfolded state is as follows: Figure 4 As shown.

[0038] Subsequently, after the device is deployed, follow-up vascular interventional treatments (such as balloon angioplasty, stent implantation, etc.) are carried out. During the treatment, plaques or thrombi at the stenotic site of vessel 400 are broken and detached by external forces, forming emboli 500 that flow distally with the blood flow. When the emboli 500 flows through the proximal protection unit 200, larger emboli 500 are intercepted by the filter pores 221 of the soft elastic filter membrane 220 of this unit; if a small number of medium-sized emboli escape from the tiny gaps or filter pores of the proximal protection unit 200, they will be further intercepted by the filter membrane with smaller pore size when they flow through the distal protection unit 200, achieving graded protection. At the same time, the graded pore size design avoids filter blockage caused by the concentrated interception of all emboli 500, ensuring normal blood perfusion and reducing the risk of ischemia in the distal vessel 400.

[0039] Finally, after the interventional treatment is completed, the device is retrieved. The surgeon slowly pulls the proximal end of the delivery guidewire 100, while simultaneously pulling each pull wire 300. Since the proximal end of the pull wire 300 is fixedly connected to the delivery guidewire 100 or the adjacent end protection unit 200, during the pulling process, the proximal openings of each protection unit 200 will gradually and slowly close into the retrieval device, first closing the nearest protection unit 200, and then closing the distal protection units 200 in sequence.

[0040] In summary, the tiered embolization protection device provided by this invention, by employing a tiered arrangement of multiple protection units and a composite structure of a flexible support frame and a soft elastic filter membrane, effectively solves the technical problems of poor flexibility, inadequate fit, and easy embolization escape in existing embolization protection devices, and significantly improves the safety and reliability of vascular interventional surgery.

[0041] It is understood that the above description is merely exemplary and the embodiments of this application do not limit the scope of the application.

[0042] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are within the protection scope of the present invention.

Claims

1. A hierarchically arranged embolic protection device comprising a delivery guidewire (100), characterized in that, The distal end of the delivery guide wire (100) is fixedly arranged with multiple protection units (200). Each protection unit (200) is open at the proximal end and closed at the distal end. Each protection unit (200) has a flexible support frame (210) for support at the target position. Multiple open areas (211) are formed on the support frame (210). A soft elastic filter membrane (220) for covering the open area (211) is arranged on the edge of each open area (211) or on the side wall of the support frame (210) as a whole. When in use, multiple protection units (200) are deployed in stages along the target position axially. The flexible support skeleton (210) of each protection unit (200) fully fits the inner wall of the blood vessel (400), and the soft elastic filter membrane (220) is used to intercept emboli (500) in the blood flow.

2. Embolization protection device of hierarchical arrangement according to claim 1, characterized in that, In any two adjacent protection units (200), the distal end of one protection unit (200) extends into the proximal end of the adjacent protection unit (200) by a set distance.

3. The graded embolism protection device according to claim 1, characterized in that, The graded embolism protection device also includes a recovery auxiliary structure for assisting in the progressive reduction of the protection unit (200) during recovery.

4. The graded embolism protection device according to claim 3, characterized in that, The recovery auxiliary structure consists of pull wires (300) arranged circumferentially along the protection unit (200). The distal end of each pull wire (300) is fixedly connected to the proximal end of the protection unit (200). The proximal end is used to receive pull, so that the proximal opening of the protection unit (200) gradually closes during the recovery process, preventing the plug (500) inside the protection unit (200) from overflowing and escaping.

5. The graded embolism protection device according to claim 4, characterized in that, The proximal end of the pull wire (300) arranged on the proximal end of the protection unit (200) is fixedly disposed on the conveying guide wire (100), and the proximal end of the pull wire (300) on the remaining protection unit (200) is fixedly disposed on the adjacent protection unit (200) located on the proximal side.

6. The graded embolism protection device according to any one of claims 1-5, characterized in that, In the plurality of protection units (200), the filter holes (221) of the soft elastic filter membrane (220) on the same protection unit (200) have the same pore size, and in any two adjacent protection units (200), the filter hole (221) of the protection unit (200) located at the near end has a larger pore size than the filter hole (221) of the protection unit (200) located at the far end.

7. The graded embolism protection device according to any one of claims 1-5, characterized in that, The support frame (210) is integrally cut and formed using an elastic memory alloy.

8. The graded embolism protection device according to any one of claims 1-5, characterized in that, The soft elastic filter membrane (220) is made of biocompatible polymer material, and the soft elastic filter membrane (220) is fixed to the sidewall of the flexible support frame (210) by hot pressing or adhesive bonding.

9. The graded embolism protection device according to claim 2, characterized in that, In any two adjacent protection units (200), the distal end of one protection unit (200) extends into the adjacent other protection unit (200) to a depth of 1 / 5 to 1 / 3 of the total length of the protection unit (200) into which it is extended.

10. The graded embolism protection device according to any one of claims 1-5, characterized in that, The hollowing rate of the flexible support frame (210) is 75%-90%.

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