Counterflow protection system and filter manufacturing method

Abstract

The application provides a reverse flow protection system and a manufacturing method of a filter. The inside of an artery sheath tube has an axial fluid passage. The artery sheath tube includes a sheath tube expansion section at the distal end section of the artery sheath tube. The sheath tube expansion section is provided with a flow guide structure. The flow guide structure includes a variable diameter tube section and a shape-changing balloon. In the distal-to-proximal direction of the artery sheath tube, the diameter of the variable diameter tube section gradually decreases, and the shape-changing balloon is wrapped around the outer periphery of the variable diameter tube section. The inflated shape-changing balloon plays a sealing role, fills the gap between the variable diameter tube section and the blood vessel wall, reduces the possibility of turbulent flow of blood in the gap between the two, and makes the blood flow more smoothly into the variable diameter tube section. Due to the effective sealing of the gap between the two, the possibility of some detached debris sinking into the turbulent flow is also effectively avoided, so that the debris can smoothly enter the established reverse blood flow, reduce or avoid the risk of stroke during carotid artery revascularization surgery, and improve the success rate and safety of the surgery.

Description

Technical Field

[0001] This application relates to the field of medical device technology, and in particular to a method for manufacturing a backflow protection system and a filter. Background Technology

[0002] Carotid artery stenosis caused by atherosclerosis is a significant cause of ischemic stroke. Surgical treatment for carotid artery stenosis mainly includes carotid endarterectomy and carotid artery stenting. Carotid endarterectomy is a traditional open surgery performed under general anesthesia, involving cutting open the carotid artery, peeling away the plaque at the narrowed site, clearing away diseased tissue, and thus relieving the stenosis. This procedure has high requirements for the patient's physical condition. Carotid artery stenting, on the other hand, is an interventional procedure that uses a stent to open the narrowed segment of the carotid artery, thereby improving blood flow. Both procedures carry the risk of plaque fragmentation and desquamation leading to distal intracranial artery embolism and stroke.

[0003] Carotid revascularization is a novel minimally invasive procedure for treating carotid artery stenosis and reducing the risk of stroke. Its basic principle is to establish an external shunt between the common carotid artery and the femoral vein, causing blood to flow backwards in the affected carotid artery during the procedure. An external filter traps plaque debris or thrombi that break off during the procedure, thus reducing the risk of emboli re-entering the bloodstream. Current carotid revascularization systems consist of a carotid sheath, a venous return sheath, and a flow control assembly with an integrated filter. The filter's pore size is approximately 200 μm. The effectiveness of the backflow is determined by the arteriovenous pressure gradient, cerebral circulation, and the total system resistance. High or low flow rates can be switched via the flow controller.

[0004] However, with existing carotid revascularization equipment, after establishing reverse blood flow, some of the detached debris may become trapped in the turbulent flow and be unable to enter the established reverse blood flow, making the carotid revascularization procedure still carry the risk of stroke. Summary of the Invention

[0005] Therefore, it is necessary to provide a method for manufacturing a backflow protection system and a filter to address the aforementioned technical problems.

[0006] This application provides a reverse current protection system, the reverse current protection system comprising:

[0007] An arterial access assembly includes an arterial sheath having an axially permeable fluid passage within its interior; the arterial sheath includes a sheath expansion section located in its distal segment, the sheath expansion section being provided with a flow guiding structure; the flow guiding structure includes a variable-diameter tube segment and a deformable balloon; wherein, from the distal end to the proximal end of the arterial sheath, the diameter of the variable-diameter tube segment gradually decreases; the deformable balloon has an inflated state and a contracted state, the deformable balloon surrounding the periphery of the variable-diameter tube segment;

[0008] A venous return assembly and a filter assembly, wherein the filter assembly is assembled between the arterial access assembly and the venous return assembly.

[0009] In one embodiment, the arterial sheath further has a filling passage that communicates with the lumen of the deformable balloon and is configured to inject filling fluid into the lumen of the deformable balloon.

[0010] In one embodiment, at least a portion of the sheath expansion section has pre-bending plasticity, and the pre-bending angle of the sheath expansion section is 0°-40°; and / or,

[0011] The arterial sheath also includes a limiting structure located in the proximal direction of the sheath dilation segment.

[0012] In one embodiment, the filtering assembly includes at least a filter, the filter including a housing and a filter element, the housing having a housing chamber and a housing inlet and a housing outlet communicating with the housing chamber;

[0013] The filter element is assembled into the housing chamber, and the housing chamber is at least divided into an upstream chamber and a downstream chamber by the filter element. The housing inlet is connected to the upstream chamber, and the housing outlet is connected to the downstream chamber.

[0014] The filter element has a cross-flow filtration zone, which has a plurality of oriented filter holes, and the axial direction of the oriented filter holes has an inclined angle relative to the surface of the cross-flow filtration zone.

[0015] In one embodiment, the axial angle between the orientation filter orifice and the surface of the cross-flow filter zone is 25°-85°; and / or,

[0016] The pore size of the oriented filter pores is 100μm-800μm; and / or,

[0017] The axial direction of the oriented filter hole forms an angle with the flow direction of the fluid entering the housing chamber from the housing inlet; and / or,

[0018] The filter element is configured as a membrane with a thickness of 100 μm-2 mm.

[0019] In one embodiment, the filter element is configured as a sheet-like filter membrane that divides the housing chamber into two chambers, namely the upstream chamber and the downstream chamber; or,

[0020] The filter element is configured as a cylindrical filter membrane having a cavity and an opening. The opening communicates with the housing inlet of the housing chamber. The cavity serves as the upstream chamber, and the remaining space in the housing chamber not occupied by the cylindrical filter membrane serves as the downstream chamber; or...

[0021] The material of the filter element includes at least one of polysulfone, polyethersulfone, polyacrylonitrile, polymethyl methacrylate, cellulose acetate, polymethylpentene, polyurethane, and thermoplastic polyurethane.

[0022] In one embodiment, the filter is provided with at least one monitoring interface, and at least one of the upstream and downstream chambers of the housing chamber is in communication with the monitoring interface, which is configured to connect a monitoring device.

[0023] In one embodiment, the filter assembly further includes a first diversion tube communicating with the housing inlet of the housing chamber, and the first diversion tube being provided with at least one of the monitoring interfaces; and / or,

[0024] The filter assembly further includes a second diversion tube, which communicates with the housing outlet of the housing chamber, and the second diversion tube is provided with at least one of the monitoring interfaces; and / or,

[0025] The monitoring device includes at least one of a pressure guide wire, a pressure sensor, a differential pressure sensor, a flow velocity sensor, and a flow rate sensor.

[0026] In one embodiment, the first diversion pipe or the housing inlet of the housing chamber is provided with a one-way valve, the one-way valve being configured to allow fluid to flow only from the housing inlet to the housing chamber; and / or,

[0027] A return pipe is connected between the first diversion pipe and the upstream chamber of the shell chamber.

[0028] This application provides a method for manufacturing a filter, the method comprising the following steps:

[0029] Polymer materials are prepared into membranes;

[0030] The membrane is fixed on a tooling platform with a preset angle, and a laser beam is used to punch holes in the membrane at the preset angle to form a plurality of oriented filter holes with an inclined orientation on the membrane, thereby obtaining a filter element.

[0031] The obtained filter element is sealed and assembled into the housing to obtain a filter.

[0032] In the aforementioned method for manufacturing the backflow protection system and filter, the expanded deformable balloon also serves a sealing function, filling the gap between the variable-diameter tubing and the vessel wall. This reduces the likelihood of turbulence forming in the gap, allowing blood to flow more smoothly into the variable-diameter tubing. Simultaneously, the effective sealing of the gap also effectively prevents some detached debris from becoming trapped in turbulence, ensuring that all debris can smoothly enter the established reverse blood flow. This reduces or eliminates the risk of stroke associated with carotid artery revascularization surgery, improving the success rate and safety of the procedure. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the usage state of a backflow protection system provided in one embodiment of this application.

[0034] Figure 2 An exploded view of an arterial access component provided in one embodiment of this application.

[0035] Figure 3 An exploded view of a venous return assembly provided in one embodiment of this application.

[0036] Figure 4 This is a front view of an arterial sheath provided in one embodiment of this application.

[0037] Figure 5 For example Figure 4 The diagram shows a partially enlarged view of the arterial sheath.

[0038] Figure 6 For example Figure 5 The image shows an AA cross-sectional view of the arterial sheath.

[0039] Figure 7 This is a perspective view of a filtering component provided in one embodiment of this application.

[0040] Figure 8 This is a top view of a filtering component provided in one embodiment of this application.

[0041] Figure 9 For example Figure 8 The BB cross-sectional view of the filter component shown.

[0042] Figure 10 For example Figure 9A partially enlarged schematic diagram of the filter assembly shown.

[0043] Figure 11 A cross-sectional view of a filter provided in another embodiment of this application.

[0044] Figure 12 A perspective view of a filtering component provided in another embodiment of this application.

[0045] Figure 13 A top view of a filtering component provided in another embodiment of this application.

[0046] Figure 14 For example Figure 13 The BB cross-sectional view of the filter component shown.

[0047] Figure 15 For example Figure 14 A partially enlarged schematic diagram of the filter assembly shown.

[0048] Icon labels:

[0049] 1000, Arterial access assembly; 2000, Venous return assembly; 3000, Filtration assembly;

[0050] 1100. Arterial sheath; 1200. Arterial sheath dilator;

[0051] 1110. Sheath expansion section; 1120. Limiting structure;

[0052] 1111. Flow guiding structure; 1112. Variable diameter pipe section; 1113. Deformable balloon;

[0053] 2100. Intravenous sheath; 2200. Intravenous sheath dilator;

[0054] 3100, Filter; 3200, Monitoring Interface; 3300, Monitoring Device; 3400, First Transfer Tube; 3500, Second Transfer Tube; 3600, Check Valve; 3700, Return Tube;

[0055] 3110. Outer casing; 3120. Filter element;

[0056] 3111, Shell chamber; 3112, Shell inlet; 3113, Shell outlet; 3114, Upstream chamber; 3115, Downstream chamber;

[0057] 3121. Cross-flow filtration zone; 3122. Oriented filter holes. Detailed Implementation

[0058] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0059] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0060] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0061] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0062] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0063] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0064] To more clearly describe the structure of the arterial access assembly 1000, the term "distal" is defined herein as the end furthest from the operator during surgical procedures, and "proximal" as the end closest to the operator during surgical procedures. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0065] See Figures 1 to 15As shown, this application provides a backflow protection system, which includes an arterial access component 1000, a venous return component 2000, and a filter component 3000. The filter component 3000 is assembled between the arterial access component 1000 and the venous return component 2000. The venous return component 2000 is used to return filtered blood to the venous system. The filter component 3000, assembled between the arterial access component 1000 and the venous return component 2000, is used to trap emboli such as plaque debris, thrombi, and lipid droplets in the blood. The venous return component 2000 may include a venous sheath 2100 and a venous sheath dilator 2200. The venous sheath dilator 2200 can be inserted into the venous sheath 2100, and the venous sheath 2100 can be guided into the blood vessel with the assistance of a guidewire. The venous sheath 2100 is used to establish venous access, allowing filtered clean blood to smoothly return to the patient's body, forming a complete arteriovenous external shunt circuit. One end of the filter assembly 3000 is connected to the fluid passage of the arterial inlet assembly 1000 via a bypass tube, and the other end is connected to the return passage of the venous return assembly 2000 via another bypass tube. The filter assembly 3000 plays a role in purifying blood in the external circuit.

[0066] See Figure 5 and Figure 6 As shown, the aforementioned arterial access assembly 1000 includes an arterial sheath 1100. The arterial sheath 1100 has an axially extending fluid passage that extends along the length (axial direction) of the arterial sheath 1100, penetrating its distal and proximal ends, providing a channel for blood flow and a path for surgical instruments. The arterial sheath 1100 includes a sheath expansion section 1110 located in its distal segment, and the sheath expansion section 1110 is provided with a flow guiding structure 1111. The flow guiding structure 1111 includes a variable-diameter tube section 1112 and a deformable balloon 1113.

[0067] In this design, the diameter of the reducing segment 1112 gradually decreases from the distal to the proximal end of the arterial sheath 1100. The distal opening of the reducing segment 1112 can be used to access the lumen of the artery, while the proximal end communicates with the fluid passage of the arterial sheath 1100. This gradually narrowing diameter design gives the reducing segment 1112 an overall funnel-shaped or flared structure. When blood flows from the artery into the arterial sheath 1100, the internal space of the reducing segment 1112 can form a blood collection cavity that gradually narrows towards the fluid passage of the arterial sheath 1100. This allows blood from the artery to flow more smoothly into the fluid passage of the arterial sheath 1100 and enter the external circuit, reducing local energy loss when blood enters the fluid passage of the arterial sheath 1100.

[0068] The deformable balloon 1113 has both an inflated and a deflated state, and surrounds the periphery of the variable-diameter segment 1112. In the deflated state, the deformable balloon 1113 can adhere to the outer surface of the variable-diameter segment 1112, facilitating the smooth puncture and entry of the arterial sheath 1100 into the blood vessel. In the inflated state, the deformable balloon 1113 can expand outward, and the degree of expansion can be adjusted to form an appropriate degree of seal with the inner wall of the blood vessel. Therefore, the inflated deformable balloon 1113 can stabilize the variable-diameter segment 1112 in the central position of the blood vessel, while ensuring that the opening of the variable-diameter segment 1112 faces the direction of blood flow.

[0069] Furthermore, the inflated deformable balloon 1113 also serves as a seal, filling the gap between the variable-diameter tube segment 1112 and the vessel wall. This reduces the likelihood of turbulence in the blood flow within this gap, allowing blood to enter the variable-diameter tube segment 1112 more smoothly. Simultaneously, the effective sealing of the gap also prevents some detached debris from becoming trapped in turbulent flow, ensuring that all debris can smoothly enter the established reverse blood flow. This reduces or eliminates the risk of stroke associated with carotid artery revascularization surgery, improving the success rate and safety of the procedure.

[0070] In the above technical solution, the diameter change of the variable diameter pipe section 1112 can be linear or nonlinear. In the case of linear change, the inner wall of the variable diameter pipe section 1112 can be a conical surface, with the diameter decreasing uniformly along the axial direction. In the case of nonlinear change, the inner wall of the variable diameter pipe section 1112 can be an arc surface, such as a concave arc surface or a convex arc surface, to further optimize the streamline morphology of blood flow and reduce flow separation and eddy current generation.

[0071] The deformable balloon 1113 can be made of compliant balloon materials, such as silicone rubber, polyurethane, or thermoplastic polyurethane, allowing the balloon to conform to the shape of the blood vessel wall in different patients during inflation, achieving better wall adhesion. The deformable balloon 1113 can also be made of non-compliant balloon materials, such as polyethylene terephthalate, allowing the balloon to have a predetermined shape and size after inflation, suitable for patients with relatively uniform anatomy. The inflation diameter of the deformable balloon 1113 can be selected according to the diameter of the target blood vessel; for example, for the common carotid artery, the outer diameter of the deformable balloon 1113 after inflation can be between 6 mm and 10 mm.

[0072] The variable diameter tubing segment 1112 and the deformable balloon 1113 can be integrally molded structures or separate structures connected by bonding, heat sealing, or ultrasonic welding. The variable diameter tubing segment 1112 can be made of medical-grade polymer materials, such as polyurethane, polyvinyl chloride, polyethylene, polypropylene, or nylon. The ratio of the distal opening diameter to the proximal diameter of the variable diameter tubing segment 1112 can be between 1.2:1 and 3:1, and more preferably between 1.5:1 and 2:1, to ensure smooth blood flow while maintaining sufficient structural strength.

[0073] In one embodiment, the arterial sheath 1100 further includes an inflation passage communicating with the lumen of the deformable balloon 1113 and configured to inject inflation fluid into the lumen of the deformable balloon 1113. For example, the inflation passage may extend along the interior wall of the arterial sheath 1100, or along the inner or outer surface of the arterial sheath 1100. One end of the inflation passage communicates with the lumen of the deformable balloon 1113, and the other end extends to the proximal end of the arterial sheath 1100 and is provided with an injection port. The inflation fluid may be saline, a mixture of contrast agent and saline, or other medical-grade injectable liquids. By injecting inflation fluid into the inflation passage, the deformable balloon 1113 can be switched from a contracted state to an inflated state. By withdrawing the inflation fluid from the inflation passage, the deformable balloon 1113 can be switched from an inflated state back to a contracted state.

[0074] At least a portion of the sheath dilation segment 1110 possesses pre-bending plasticity, and the pre-bending angle of the sheath dilation segment 1110 is 0°-40°. For example, 5°, 10°, 15°, 20°, 25°, 30°, 35°, and 40°. Pre-bending plasticity refers to the sheath dilation segment 1110 being pre-bent to a specific angle during manufacturing and maintaining this bent shape during use without self-rebound. This pre-bending design allows the sheath dilation segment 1110 to be inserted parallel to the vessel's course after insertion into the carotid artery, preventing the tip of the sheath dilation segment 1110 from pressing against the opposite vessel wall. The pre-bending angle can be selected within the range of 0 to 40 degrees based on the anatomical curvature of the human carotid artery. 0 degrees represents no pre-bending, i.e., a straight tube shape, suitable for patients with relatively straight vessel courses. 40 degrees represents a larger pre-bending angle, suitable for patients with greater carotid artery curvature. The pre-bending angle can also be further preferably 15 to 30 degrees to cover the anatomical needs of most patients.

[0075] See Figure 5 and Figure 6As shown, the arterial sheath 1100 also includes a limiting structure 1120, which is located proximally to the sheath expansion section 1110. For example, the limiting structure 1120 can be a protruding structure such as an annular boss, wing, or protrusion extending radially outward from the outside of the arterial sheath 1100. This protruding structure can be directly located on the outer surface of the arterial sheath 1100, or it can be separated from the arterial sheath 1100 by an outer sleeve, such as a silicone sleeve, with the protruding structure then positioned on the surface of the outer sleeve. Those skilled in the art can design this according to actual needs, and no limitations are imposed here.

[0076] The limiting structure 1120 is used to abut against the tissue or skin at the vascular puncture site to limit the depth of insertion of the arterial sheath 1100 into the blood vessel, preventing damage to the posterior wall of the blood vessel or intracranial vessels due to excessive insertion. The axial distance between the limiting structure 1120 and the sheath dilation section 1110 can be predetermined according to the puncture depth of the target blood vessel; for example, for common carotid artery puncture, this distance can be between 2 cm and 5 cm.

[0077] In addition, the arterial sheath 1100 may also include a vent valve. The vent valve is installed proximally or on the side wall of the arterial sheath 1100 and is selectively in communication with the fluid passage. The vent valve is used to expel gas or liquid from the fluid passage, such as venting air from the fluid passage at the start of surgery or venting blood from the fluid passage at the end of surgery. The arterial sheath 1100 may also include an instrument inlet. The instrument inlet is located proximally in the arterial sheath 1100 and is in communication with the fluid passage for introducing surgical instruments such as guidewires, balloon catheters, and stent delivery systems.

[0078] The aforementioned filling pathway, pre-bending plasticity, limiting structure 1120, venting valve, and device inlet, among other technical features, can be implemented in any combination and are not limited herein. The arterial access assembly 1000 also includes an arterial sheath dilator 1200, which can be inserted into the arterial sheath and can be guided through a guidewire to assist in the introduction of the arterial sheath 1100 into the blood vessel.

[0079] See Figures 7 to 15As shown, in one embodiment, the filter assembly 3000 includes at least a filter 3100. The filter 3100 includes a housing 3110 and a filter element 3120. The housing 3110 has a housing chamber 3111 and a housing inlet 3112 and a housing outlet 3113 communicating with the housing chamber 3111. The housing inlet 3112 is used to receive blood from the arterial inlet assembly 1000, and the housing outlet 3113 is used to deliver filtered blood to the venous return assembly 2000. The filter element 3120 is fitted into the housing chamber 3111, and the housing chamber 3111 is at least divided by the filter element 3120 into an upstream chamber 3114 and a downstream chamber 3115. The housing inlet 3112 communicates with the upstream chamber 3114, allowing unfiltered blood to enter the upstream chamber 3114 first. The housing outlet 3113 communicates with the downstream chamber 3115, allowing filtered blood to flow out of the downstream chamber 3115.

[0080] See Figure 11 As shown, the filter element 3120 has a cross-flow filtration zone 3121, with several oriented filter holes 3122 formed in the cross-flow filtration zone 3121. The axial direction of the oriented filter holes 3122 is inclined at an angle relative to the surface of the cross-flow filtration zone 3121. This inclined orientation design means that the oriented filter holes 3122 are no longer perpendicular to the surface of the cross-flow filtration zone 3121, but rather form a certain angle with it. The design concept of the cross-flow filtration zone 3121 is to change the flow mode of blood in the cross-flow filtration zone 3121. That is, after the blood enters the housing chamber 3111, it does not directly impact the surface of the cross-flow filtration zone 3121 of the filter element 3120, but flows parallel or substantially parallel to the cross-flow filtration zone 3121 of the filter element 3120. Under this flow mode, the mainstream direction of the blood is tangent or substantially tangent to the surface of the cross-flow filtration zone 3121 of the filter element 3120, rather than perpendicularly pointing towards the oriented filter holes 3122. Therefore, under the shear force of parallel flow, particulate matter in the blood is less likely to be directly embedded in the orientation filter pores 3122, but is more easily carried away by the liquid flow, thereby reducing the positive impact of particulate matter on the orientation filter pores 3122 and the concentration of local pressure difference.

[0081] The outer casing 3110 can be made of medical-grade transparent polymer material, such as polycarbonate, acrylonitrile-butadiene-styrene copolymer, or polymethyl methacrylate, to facilitate observation of blood flow and filter residue accumulation within the filter 3100 during surgery. The outer casing 3110 may also be equipped with an exhaust port to expel gas from the casing chamber 3111. The casing inlet 3112 and casing outlet 3113 can be located on the same side of the outer casing 3110 or on opposite sides. The axes of the casing inlet 3112 and casing outlet 3113 can be parallel, perpendicular, or at other angles to accommodate the layout requirements of external tubing.

[0082] In one embodiment, the axial angle between the orientation filter orifice 3122 and the surface of the cross-flow filter zone 3121 is 25°-85°. Examples include 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, and 85°. The tilt angle refers to the angle between the central axis of the orientation filter orifice 3122 and the surface of the cross-flow filter zone 3121. When the tilt angle is less than 90 degrees, the orientation filter orifice 3122 is an oblique orifice. The tilt angle range of 25° to 85° covers various situations from gentle to steep inclinations. Smaller tilt angles, such as 25° to 40°, allow the orientation filter orifice 3122 to be more elongated, making it more difficult for particles to enter directly. Larger tilt angles, such as 50° to 85°, allow the orientation filter orifice 3122 to be closer to vertical, resulting in lower fluid resistance. Therefore, those skilled in the art can make targeted structural designs based on various factors such as the size of the target filter particles and the blood flow rate, without making any limitations here.

[0083] The pore size of the oriented filter pore 3122 ranges from 100 μm to 800 μm. Examples include 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, 600 μm, 650 μm, 700 μm, 750 μm, and 800 μm. The pore size of the oriented filter pore 3122 refers to the cross-sectional dimension of the oriented filter pore 3122 in the direction perpendicular to its axial direction. For circular pores, the pore size is the diameter. For non-circular pores, the pore size can be understood as the equivalent diameter. The pore size range of 100 μm to 800 μm covers various cases from smaller to larger pore sizes. For example, smaller pore sizes of 100 μm to 300 μm can trap smaller particles, including tiny plaque debris and lipid droplets. Larger pore sizes, such as 300μm to 800μm, are beneficial for reducing fluid resistance.

[0084] The axial direction of the oriented filter orifice 3122 forms an angle with the flow direction of fluid entering the housing chamber 3111 from the housing inlet 3112. For example, this angle can be designed as an obtuse angle, so that the opening direction of the oriented filter orifice 3122 is opposite to the mainstream blood flow direction. When blood flows parallel to the cross-flow filtration zone 3121, the particles in the blood move with the mainstream. Since the tilt direction of the oriented filter orifice 3122 forms an obtuse angle with the mainstream flow direction, the particles need to change their direction of movement to enter the oriented filter orifice 3122. This increases the difficulty for particles to enter the oriented filter orifice 3122 and makes them easier to be washed away by the subsequent liquid flow, thereby reducing the risk of particles getting stuck.

[0085] See Figures 7 to 11 As shown, the filter element 3120 is configured as a membrane with a thickness of 100 μm to 2 mm. The membrane thickness affects the strength and filtration performance of the filter element 3120. The thickness range of 100 μm to 2 mm covers a variety of membrane types, from thinner to thicker. For example, thinner membranes (100 μm to 500 μm) have lower fluid resistance and higher filtration flux. Thicker membranes (500 μm to 2 mm) have higher mechanical strength and better dimensional stability. Those skilled in the art can select an appropriate thickness based on material properties and application requirements.

[0086] In one embodiment, the filter element 3120 can be configured as a sheet-like filter membrane that divides the housing chamber 3111 into two chambers, namely the upstream chamber 3114 and the downstream chamber 3115. The sheet-like filter membrane can be a flat or slightly curved sheet structure. The outer peripheral edge of the sheet-like filter membrane is sealed to the inner wall of the housing 3110, for example, by heat sealing, ultrasonic welding, or bonding. One side of the sheet-like filter membrane forms the upstream chamber 3114, and the other side forms the downstream chamber 3115. Based on the aforementioned structural design of the oriented filter hole 3122, after blood enters the upstream chamber 3114 from the housing inlet 3112, it can flow parallel or substantially parallel to the surface of the sheet-like filter membrane. Some blood enters the downstream chamber 3115 through the oriented filter hole 3122, while blood that does not pass through the oriented filter hole 3122 continues to flow and can be returned via the return pipe 3700. The sheet-like filter membrane has a simple structure and is easy to manufacture and assemble.

[0087] See Figures 12 to 15As shown, the filter element 3120 can also be configured as a cylindrical filter membrane. The cylindrical filter membrane has a cavity and an opening, with the opening facing the housing inlet 3112 and communicating with the housing inlet 3112 of the housing chamber 3111. The cavity serves as the upstream chamber 3114, and the remaining space in the housing chamber 3111 not occupied by the cylindrical filter membrane serves as the downstream chamber 3115. Specifically, the annular space between the outer wall of the cylindrical filter membrane and the inner wall of the outer casing 3110 forms the downstream chamber 3115. The cylindrical filter membrane can be cylindrical, conical, or other shapes of revolution. After blood enters the cavity from the housing inlet 3112, it flows axially or spirally along the inner wall surface of the cylindrical filter membrane. Some blood enters the downstream chamber 3115 through the orientation filter holes 3122, while blood that does not pass through the filter holes continues to flow towards the bottom of the cylinder and can return via the return pipe 3700. The cylindrical filter membrane has a larger filtration area, enabling it to provide a higher filtration flux within a limited space.

[0088] The filter element 3120 is made of at least one of polysulfone (PSU), polyethersulfone (PES), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), cellulose acetate (CTA), polymethylpentene (PMP), polyurethane, and thermoplastic polyurethane. All of the aforementioned materials exhibit good blood compatibility. Polysulfone and polyethersulfone possess excellent mechanical strength and chemical stability. Polyacrylonitrile exhibits good hydrophilicity and resistance to protein adsorption. Polymethyl methacrylate offers high transparency for easy observation. Cellulose acetate exhibits good biocompatibility. Polymethylpentene has a low protein binding rate. Polyurethane and thermoplastic polyurethane possess good flexibility and elasticity. The above materials can be used alone, or blended or copolymerized in combination to leverage their respective advantages; no limitation is made herein.

[0089] In one embodiment, the filter 3100 is provided with at least one monitoring interface 3200, and at least one of the upstream chamber 3114 and the downstream chamber 3115 of the housing chamber 3111 is in communication with the monitoring interface 3200. The monitoring interface 3200 is configured for connecting a monitoring device 3300. The monitoring interface 3200 may be disposed on the wall of the housing 3110 and directly communicate with the upstream chamber 3114 or the downstream chamber 3115. The monitoring interface 3200 may be designed as a tubular structure, and its end may be provided with a Luer connector or a hemostatic valve to facilitate quick connection to the monitoring device 3300. There may be one, two, or more monitoring interfaces 3200.

[0090] When monitoring interface 3200 is only connected to upstream chamber 3114, data such as pressure, flow rate, or flow rate upstream of filter 3100 can be measured through monitoring device 3300. When monitoring interface 3200 is only connected to downstream chamber 3115, data such as pressure, flow rate, or flow rate downstream of filter 3100 can be measured. When monitoring interfaces 3200 are set up simultaneously upstream and downstream, data such as pressure difference between upstream and downstream can be calculated. For example, changes in pressure difference can reflect the degree of clogging of filter element 3120 or changes in system resistance, thereby assisting in determining whether filter assembly 3000 needs to be replaced or the backflow state needs to be adjusted.

[0091] Before surgery, the operator can measure the baseline differential pressure via monitoring interface 3200 as a reference value. As the surgery progresses, detached plaque debris is gradually trapped on filter element 3120, causing the fluid resistance of filter element 3120 to gradually increase, the upstream pressure to rise and the downstream pressure to fall, resulting in a larger differential pressure. When the differential pressure exceeds a preset threshold, it indicates that filter element 3120 may be partially blocked. The operator can then decide to replace filter 3100 or adjust the surgical strategy, thereby greatly improving the controllability and safety of the surgery.

[0092] See Figures 7 to 15 As shown, in one embodiment, the filter assembly 3000 further includes a first diversion tube 3400, which communicates with the housing inlet 3112 of the housing chamber 3111, and the first diversion tube 3400 is provided with at least one monitoring interface 3200. The first diversion tube 3400 is a conduit connecting the arterial access assembly 1000 and the housing inlet 3112 of the filter 3100. The monitoring interface 3200 on the first diversion tube 3400 can monitor the state of the blood before it enters the filter 3100. The monitoring interface 3200 on the first diversion tube 3400 can be a three-way valve, a side branch tube, or a puncture-type interface. The monitoring device 3300 can be connected to the inside of the conduit through this interface.

[0093] The filter assembly 3000 also includes a second diversion tube 3500, which communicates with the housing outlet 3113 of the housing chamber 3111, and is provided with at least one monitoring interface 3200. The second diversion tube 3500 is a conduit connecting the housing outlet 3113 of the filter 3100 to the venous return assembly 2000. The monitoring interface 3200 on the second diversion tube 3500 allows monitoring of the blood state after it leaves the filter 3100. By comparing the monitoring data on the first diversion tube 3400 and the second diversion tube 3500, parameters such as the pressure difference and flow rate difference before and after the filter 3100 can be obtained.

[0094] The monitoring device 3300 includes at least one of a pressure guidewire, a pressure sensor, a differential pressure sensor, a flow velocity sensor, and a flow rate sensor. The pressure guidewire is a pressure measuring device that can be inserted into the tubing to directly measure pressure in the blood flow. The pressure sensor can be mounted on the monitoring interface 3200 and measures pressure through liquid conduction or diaphragm sensing. The differential pressure sensor can directly output the pressure difference between two measuring points. The flow velocity sensor can measure the instantaneous flow velocity of blood. The flow rate sensor can measure the volume of blood flowing per unit time. The monitoring device 3300 can be used individually or in combination as needed clinically. In addition, the monitoring interface 3200 can also be connected to a miniature ultrasonic flow detection device, which can be clamped or attached to the outer wall of the tubing to measure the flow velocity and flow rate of blood within the tubing through the ultrasonic Doppler effect, achieving non-invasive monitoring.

[0095] See Figure 10 As shown, in one embodiment, a one-way valve 3600 is provided at the housing inlet 3112 of the first diversion tube 3400 or housing chamber 3111. The one-way valve 3600 is configured to allow fluid to flow only from the housing inlet 3112 to the housing chamber 3111. The one-way valve 3600 can be in various forms, such as a valve valve or a ball valve. The function of the one-way valve 3600 is to prevent blood from flowing back from the filter 3100 to the arterial inlet assembly 1000. In the extracorporeal circuit, blood backflow may occur if the pressure at the venous end is higher than that at the arterial end, or if the extracorporeal pump stops operating. The one-way valve 3600 effectively prevents backflow, maintains the correct flow direction of blood in the circuit, and prevents particles trapped on the filter 3120 from being flushed back into the arterial inlet.

[0096] See Figure 15 As shown, a return pipe 3700 connects the first diversion pipe 3400 and the upstream chamber 3114 of the housing chamber 3111. For example, one end of the return pipe 3700 can be connected between the one-way valve 3600 and the upstream chamber 3114, and the other end can be connected above the upstream chamber 3114, thereby ensuring that the embolus in the return pipe 3700 will not flow back into the carotid artery. The return pipe 3700 can be used to realize the circulation function of filtration. In filtration mode, the blood entering the upstream chamber 3114 may not all pass through the oriented filter element 3120 into the downstream chamber 3115, thus forming a circulation. This circulation flow can continuously flush the surface of the filter element 3120, carrying away the particles accumulated on the membrane surface and preventing particles from depositing and clogging the oriented filter pores 3122. A flow regulating valve or a drive pump can be installed on the return pipe 3700 to adjust the circulation flow rate and optimize the filtration effect.

[0097] This application provides a method for manufacturing a filter 3100, the method comprising the following steps:

[0098] Polymer materials are prepared into films. For example, the polymer material can be selected from polysulfone, polyethersulfone, polyacrylonitrile, polymethyl methacrylate, cellulose acetate, polymethylpentene, polyurethane, thermoplastic polyurethane, and blends or copolymers of the aforementioned materials. The film can be prepared by solution casting, hot pressing, or extrusion. Solution casting involves dissolving the polymer in a suitable solvent, casting it onto a flat substrate, and allowing the solvent to evaporate to form a film. Hot pressing involves heating polymer particles or powder to a molten state and pressing it into shape in a mold. Extrusion involves extruding molten polymer through a slit die, and cooling it to form a film.

[0099] A diaphragm is fixed to a fixture platform with a preset angle. A laser beam is used to drill holes in the diaphragm at the preset angle, forming several oriented filter holes 3122 with an inclined orientation on the diaphragm, resulting in a filter element 3120. For example, the fixture platform can be a tiltable worktable, and its tilt angle can be adjusted arbitrarily between 0 and 90 degrees. The preset angle is the desired tilt angle of the oriented filter holes 3122, which can be designed to be between 25 and 85 degrees. Laser drilling can use an ultraviolet laser, a femtosecond laser, or a picosecond laser to obtain high-precision, heat-free hole wall quality. During drilling, the laser beam is incident perpendicularly to the surface of the fixture platform. Since the diaphragm is tilted relative to the laser beam, an angle is formed between the laser beam and the normal of the diaphragm, thus forming inclined channels on the diaphragm. By controlling the laser pulse energy, pulse width, repetition frequency, and scanning path, the hole diameter, hole spacing, and porosity can be precisely controlled. After drilling is completed, the morphology and size of the channels can be observed under a microscope.

[0100] The resulting filter element 3120 is sealed and assembled into the housing 3110 to obtain the filter 3100. For example, the sealing assembly can be achieved by bonding, heat sealing, ultrasonic welding, or laser welding. During assembly, it must be ensured that the filter element 3120 reliably divides the housing chamber 3111 into an upstream chamber 3114 and a downstream chamber 3115. If the filter element 3120 uses a sheet-like filter membrane, the sheet-like filter membrane can divide the housing chamber 3111 into the upstream chamber 3114 and the downstream chamber 3115 located on both sides, with no other connecting path between them except for the oriented filter holes 3122. After assembly, a sealing test and a pressure test can be performed to ensure that the filter 3100 will not leak during use. Blood compatibility tests and filtration efficiency tests can also be performed to verify the performance of the filter 3100.

[0101] In another embodiment, if the filter element 3120 is a cylindrical filter membrane, the assembly of the cylindrical filter membrane can also divide the interior of the housing chamber 3111 into an upstream chamber 3114 and a downstream chamber 3115. The upstream chamber 3114 is formed by the cylindrical cavity of the cylindrical filter membrane, while the downstream chamber 3115 is formed by other spaces in the housing chamber 3111 not occupied by the cylindrical filter membrane and its cavity. The cylindrical filter membrane has an opening that faces and communicates with the housing inlet 3112 of the housing chamber 3111, allowing arterial blood to directly enter the cylindrical cavity.

[0102] The shell outlet 3113 of the shell chamber 3111 communicates with the downstream chamber 3115, allowing filtered blood to flow out. During assembly, a sealed connection is ensured between the opening of the cylindrical filter membrane and the shell inlet 3112. Sealing methods include bonding, heat sealing, ultrasonic welding, or laser welding. For example, if the cylindrical filter membrane has a mesh structure, both ends can be sealed with a polymer material. Simultaneously, the space between the outer wall of the cylindrical filter membrane and the inner wall of the outer shell 3110 forms the downstream chamber 3115.

[0103] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0104] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A backflow protection system, characterized in that, The backflow protection system includes: An arterial access assembly includes an arterial sheath having an axially permeable fluid passage within its interior; the arterial sheath includes a sheath expansion section located in its distal segment, the sheath expansion section being provided with a flow guiding structure; the flow guiding structure includes a variable-diameter tube segment and a deformable balloon; wherein, from the distal end to the proximal end of the arterial sheath, the diameter of the variable-diameter tube segment gradually decreases; the deformable balloon has an inflated state and a contracted state, the deformable balloon surrounding the periphery of the variable-diameter tube segment; A venous return assembly and a filter assembly, wherein the filter assembly is assembled between the arterial access assembly and the venous return assembly.

2. The backflow protection system according to claim 1, characterized in that, The arterial sheath also has a filling passage that communicates with the lumen of the deformable balloon and is configured to inject filling fluid into the lumen of the deformable balloon.

3. The backflow protection system according to claim 1, characterized in that, At least a portion of the expanded section of the sheath tube has pre-bending plasticity, and the pre-bending angle of the expanded section of the sheath tube is 0°-40°. And / or, the arterial sheath further includes a limiting structure located in the proximal direction of the sheath dilation segment.

4. The backflow protection system according to claim 1, characterized in that, The filtration assembly includes at least a filter, the filter including a housing and a filter element, the housing having a housing chamber and a housing inlet and a housing outlet communicating with the housing chamber; The filter element is assembled into the housing chamber, and the housing chamber is at least divided into an upstream chamber and a downstream chamber by the filter element. The housing inlet is connected to the upstream chamber, and the housing outlet is connected to the downstream chamber. The filter element has a cross-flow filtration zone, which has a plurality of oriented filter holes, and the axial direction of the oriented filter holes has an inclined angle relative to the surface of the cross-flow filtration zone.

5. The backflow protection system according to claim 4, characterized in that, The axial angle between the orientation filter holes and the surface of the cross-flow filter zone is 25°-85°; and / or, The pore size of the oriented filter pores is 100μm-800μm; and / or, The axial direction of the oriented filter hole forms an angle with the flow direction of the fluid entering the housing chamber from the housing inlet; and / or, The filter element is configured as a membrane with a thickness of 100 μm-2 mm.

6. The backflow protection system according to claim 4, characterized in that, The filter element is configured as a sheet-like filter membrane that divides the housing chamber into two chambers, namely the upstream chamber and the downstream chamber; or... The filter element is configured as a cylindrical filter membrane having a cavity and an opening. The opening communicates with the housing inlet of the housing chamber. The cavity serves as the upstream chamber, and the remaining space in the housing chamber not occupied by the cylindrical filter membrane serves as the downstream chamber; or... The material of the filter element includes at least one of polysulfone, polyethersulfone, polyacrylonitrile, polymethyl methacrylate, cellulose acetate, polymethylpentene, polyurethane, and thermoplastic polyurethane.

7. The backflow protection system according to claim 4, characterized in that, The filter is provided with at least one monitoring interface, and at least one of the upstream and downstream chambers of the housing chamber is connected to the monitoring interface, which is configured to connect a monitoring device.

8. The backflow protection system according to claim 7, characterized in that, The filter assembly further includes a first diversion tube, which communicates with the housing inlet of the housing chamber, and the first diversion tube is provided with at least one of the monitoring interfaces; and / or, The filter assembly further includes a second diversion tube, which communicates with the housing outlet of the housing chamber, and the second diversion tube is provided with at least one of the monitoring interfaces; and / or, The monitoring device includes at least one of a pressure guide wire, a pressure sensor, a differential pressure sensor, a flow velocity sensor, and a flow rate sensor.

9. The backflow protection system according to claim 8, characterized in that, The first diversion pipe or the housing inlet of the housing chamber is provided with a one-way valve, the one-way valve being configured to allow fluid to flow only from the housing inlet to the housing chamber; and / or, A return pipe is connected between the first diversion pipe and the upstream chamber of the shell chamber.

10. A method for manufacturing a filter as described in any one of claims 4-9, characterized in that, The manufacturing method includes the following steps: Polymer materials are prepared into membranes; The membrane is fixed on a tooling platform with a preset angle, and a laser beam is used to punch holes in the membrane at the preset angle to form a plurality of oriented filter holes with an inclined orientation on the membrane, thereby obtaining a filter element. The obtained filter element is sealed and assembled into the housing to obtain a filter.

Images